WO2014049947A1 - Method for inspecting glass substrate for information storage medium, and method for manufacturing glass substrate for information storage medium - Google Patents

Method for inspecting glass substrate for information storage medium, and method for manufacturing glass substrate for information storage medium Download PDF

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Publication number
WO2014049947A1
WO2014049947A1 PCT/JP2013/004957 JP2013004957W WO2014049947A1 WO 2014049947 A1 WO2014049947 A1 WO 2014049947A1 JP 2013004957 W JP2013004957 W JP 2013004957W WO 2014049947 A1 WO2014049947 A1 WO 2014049947A1
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WIPO (PCT)
Prior art keywords
glass substrate
inspection
cleaning
polishing
information recording
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PCT/JP2013/004957
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French (fr)
Japanese (ja)
Inventor
遠藤　毅
直之 福本
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Hoya株式会社
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Publication of WO2014049947A1 publication Critical patent/WO2014049947A1/en

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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
    • G11B5/8404—Processes or apparatus specially adapted for manufacturing record carriers manufacturing base layers

Definitions

  • the present invention relates to a method for inspecting a glass substrate for information recording medium and a method for manufacturing a glass substrate for information recording medium.
  • a typical example of such an information recording apparatus is a hard disk drive apparatus.
  • a hard disk drive device is a device that magnetically records (writes) information on a magnetic disk (hard disk) as an information recording medium having a recording layer formed on a substrate, and reproduces (reads) the recorded information. is there.
  • a so-called substrate a glass substrate is preferably used.
  • the hard disk drive device floats the magnetic head with respect to the magnetic disk without contacting the magnetic disk when information is recorded on or read from the magnetic disk. It is known that the recording density can be improved by reducing the flying height of the magnetic head. In recent years, the recording density of a magnetic disk by the perpendicular magnetic recording system has been increased, and the flying height of the magnetic head has been reduced to about several nanometers. For this reason, if the information recording medium has a defect based on a foreign substance defect on the glass substrate, the flying of the magnetic head becomes unstable and the magnetic head and the magnetic disk collide with each other, so-called a head crash phenomenon. May occur. Even when the head does not crash, it may affect the flying stability of the magnetic head.
  • the glass substrate for information recording medium has few defects. For this reason, defect inspection for inspecting the number and size of defects of the glass substrate for information recording media has become important.
  • Patent Document 1 As a method for inspecting defects such as foreign matter defects, for example, the method described in Patent Document 1 can be cited.
  • Patent Document 1 discloses a method of manufacturing a magnetic disk glass substrate including an inspection process for inspecting the manufactured magnetic disk glass substrate, wherein in the inspection process, the size of the defect on the magnetic disk glass substrate is determined.
  • a method for manufacturing a glass substrate for magnetic disk is described which determines pass / fail of a glass substrate for magnetic disk based on a plurality of determination criteria determined by the number. According to Patent Document 1, it is disclosed that it is possible to make a determination with higher accuracy than in the case where the pass / fail determination is performed only by the number of defects.
  • An object of the present invention is to provide a method for inspecting a glass substrate for an information recording medium capable of accurately detecting defects that are difficult to remove by cleaning. Moreover, this invention aims at providing the manufacturing method of the glass substrate for information recording media which used this test
  • One aspect of the present invention is to detect a defect present on the surface of the glass substrate and obtain positional information of the defect, and after the first inspection step, clean the surface of the glass substrate.
  • a glass substrate inspection method for an information recording medium comprising: a determination step of determining pass / fail of the glass substrate on the basis of the number of coincident positions of defect positions acquired in the second inspection step.
  • Another aspect of the present invention is a polishing step for polishing a plurality of glass substrates, a post-polishing cleaning step for cleaning the surfaces of the plurality of glass substrates after the polishing step, and the post-polishing cleaning.
  • FIG. 1 is a drawing for explaining an inspection method according to an embodiment of the present invention.
  • FIG. 2 is a schematic cross-sectional view showing an example of a polishing apparatus used in a polishing step in the method for manufacturing a glass substrate for information recording medium according to the embodiment of the present invention.
  • FIG. 3 is a top view showing a glass base plate used in the method for manufacturing a glass substrate for information recording medium according to the embodiment of the present invention.
  • FIG. 4 is a process diagram showing an example of a method for producing a glass substrate for information recording media according to an embodiment of the present invention.
  • FIG. 5 is a process diagram showing another example of the method for manufacturing the glass substrate for information recording medium according to the embodiment of the present invention.
  • FIG. 1 is a drawing for explaining an inspection method according to an embodiment of the present invention.
  • FIG. 2 is a schematic cross-sectional view showing an example of a polishing apparatus used in a polishing step in the method for manufacturing a glass substrate for information recording medium according to the embodiment of the
  • FIG. 6 is a process diagram showing an example of a method for producing a glass substrate for an information recording medium for comparison with an embodiment of the present invention.
  • FIG. 7 is a partial cross-sectional perspective view showing a magnetic disk as an example of a magnetic recording medium using the glass substrate for information recording medium manufactured by the method for manufacturing the glass substrate for information recording medium according to the present embodiment.
  • the determination based on the size and number of defects as in the method described in Patent Document 1 may not be sufficient as a defect determination. That is, in such a determination, if the determination criterion is low, defective products cannot be sufficiently excluded, and if the determination criterion is increased, what should be originally passed is determined as a defective product and eliminated. It was found that so-called overkill occurs.
  • the present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for inspecting a glass substrate for an information recording medium that can accurately detect defects that are difficult to remove by cleaning. Moreover, this invention aims at providing the manufacturing method of the glass substrate for information recording media which used this test
  • the inspection method of the glass substrate for information recording media concerning this embodiment detects the defect which exists in the surface of the glass substrate, and acquires the position information (first position information) of the defect, After the first inspection process, a cleaning process for cleaning the surface of the glass substrate, and after the cleaning process, a defect present on the surface of the glass substrate is detected, and position information (second position information) of the defect is obtained.
  • the pass / fail of the glass substrate is determined based on the number of the second position information and the first position information that is acquired in advance before cleaning in the cleaning step. It is a method to do. That is, the determination criterion in the determination step in the inspection method according to the present embodiment is the number of the first position information and the second position information that match. The number used for this determination is considered to be the number of defects that did not move in the cleaning step. This number is considered to be the number of defects that are difficult to remove by cleaning. From this, the inspection method according to the present embodiment can determine pass / fail of the glass substrate based on the number of defects that are difficult to remove by cleaning.
  • the defect detected in the second inspection process, and the defect in which the first position information and the second position information do not match is reattached in the cleaning process.
  • the defect is a defect that can be removed by cleaning again.
  • the inspection method makes a determination based on the number of coincidence of the first position information and the second position information, not the number of defects detected in the second inspection step. Therefore, regardless of the number of defects that can be easily removed by cleaning, the pass / fail of the glass substrate can be determined based on the number of defects that are difficult to remove by cleaning.
  • Defects that are difficult to remove by washing are removed even if the glass substrate is washed, for example, washed before forming a recording layer when manufacturing an information recording medium.
  • Defects that are difficult to remove such as non-removable defects (NRD). Specifically, it refers to a defect that does not move even after a cleaning process as described later. More specifically, a defect that cannot be removed, such as a foreign substance defect firmly attached to a glass substrate, can be mentioned.
  • NTD non-removable defects
  • the glass substrate that is the inspection object is not particularly limited as long as it is a glass substrate for an information recording medium.
  • the glass substrate for information recording media manufactured separately, the glass substrate of the last stage at the time of manufacturing the glass substrate for information recording media, etc. are mentioned. That is, this inspection method may inspect a separately manufactured glass substrate for information recording medium, or may be applied to a final stage process or the like when manufacturing a glass substrate for information recording medium.
  • the cleaning process is a final cleaning process in the manufacturing method of the glass substrate for information recording medium, which will be described in detail later. There may be a cleaning step that is performed separately for inspection after the final cleaning step.
  • the size of the glass substrate that is an inspection object is not particularly limited, and examples thereof include a glass substrate having a diameter of 65 mm and a thickness of 0.8 mm, a glass substrate having a diameter of 48 mm and a thickness of 0.5 mm, and the like.
  • the first inspection step is not particularly limited as long as it is a step capable of detecting a defect present on the surface of the glass substrate and acquiring positional information of the defect.
  • a method using an inspection apparatus capable of detecting a defect present on the surface of a glass substrate and acquiring position information thereof can be used.
  • a method using optical means can be used. Specifically, a method of irradiating a glass substrate with inspection light and detecting a defect based on reflected light and scattered light of the inspection light can be used. Such a method is preferable in that a defect can be detected by a simple method.
  • the inspection can be performed by using a laser scattering surface inspection device (a disk surface inspection device NS7300R manufactured by Hitachi High-Technologies Corporation). Note that such a surface inspection apparatus measures the presence / absence, position, and number of defects by observing scattered / reflected light by laser light irradiation, and discriminates defects by their size and signal characteristics. .
  • a laser scattering surface inspection device a disk surface inspection device NS7300R manufactured by Hitachi High-Technologies Corporation.
  • the cleaning step is not particularly limited as long as the surface of the glass substrate can be cleaned.
  • the final cleaning step in the method for producing a glass substrate for an information recording medium can be mentioned. That is, cleaning under the same conditions as in the final cleaning step can be mentioned. Specifically, cleaning with a detergent, ultrasonic cleaning in which a glass substrate is immersed in a cleaning solution, and high-frequency ultrasonic waves are applied can be used. In addition to these cleaning operations, scrub cleaning may be performed. The cleaning process does not need to remove defects that can be easily removed by cleaning, and may be moved more easily. Therefore, the cleaning process may be simpler than the final cleaning process.
  • the final cleaning step is usually a step in which 10 or more tanks for performing the above-described cleaning are provided and cleaned using them. In the cleaning process in the inspection method according to the present embodiment, about 5 tanks are used. It may be.
  • the second inspection step is not particularly limited as long as it is a step capable of detecting a defect present on the surface of the glass substrate and acquiring positional information of the defect.
  • the second position information which is the inspection result in the second inspection step, is compared with the first position information obtained in advance, and the presence / absence of defect movement is observed. Therefore, it is preferable that the second inspection step is the same as the first inspection step.
  • the determination step is not particularly limited as long as it is a step for determining pass / fail of the glass substrate based on the number of the first position information and the second position information that coincide with each other. That is, whether the glass substrate is acceptable or not is determined regardless of the number of defects detected in the first inspection step and the second inspection step.
  • the determination step can be performed by collating the first position information and the second position information stored in the inspection apparatus by the control unit of the inspection apparatus and outputting the number of coincidence. it can. And if the number is below a predetermined number, it will determine with a pass, and if it exceeds a predetermined number, it will determine with a failure.
  • the reference number varies depending on the quality required for the glass for the information recording medium. For example, when the reference number is 0, if the first position information and the second position information do not match at all, the pass is accepted.
  • the inspection method according to the present embodiment can determine pass / fail of the glass substrate based on the number of defects that are difficult to remove by cleaning, regardless of the number of defects that can be easily removed by cleaning, with the above configuration. .
  • the inspection method according to the present embodiment is specifically the following inspection method.
  • FIG. 1 is a drawing for explaining an inspection method according to the present embodiment.
  • the first inspection step as shown in FIG. 1A, five defects 2 existing on the surface of the glass substrate 1 are detected, and position information of the defects 2 is acquired. Thereafter, the surface of the glass substrate is cleaned in the cleaning step. After the cleaning, the second inspection process is performed. As a result, as shown in FIG. 1B, three defects 3 and 4 are detected on the surface of the glass substrate, and their positional information is acquired. Then, by comparing the position information in the determination step, the three defects detected in the second inspection step are two defects 3 having the same position information before and after the cleaning step. It can be seen that one defect 4 that does not match is included.
  • the pass / fail of the glass substrate 1 is determined based on the determination criterion of two, which is the number of the matching defects 3.
  • the same inspection as the first inspection step and the second inspection step is performed once on the glass substrate, and the pass / fail of the glass substrate is determined based on the number and size of the detected defects.
  • the pass / fail of the glass substrate was determined even if the above inspection is performed a plurality of times, it is not determined by the number of pieces in which the positional information is matched, but in each inspection, by the number and size of detected defects. The pass / fail of the glass substrate was determined. For this reason, in many cases, a case where there is a large defect such as scratch or scratch is rejected. For example, a small adhesion defect of 1 ⁇ m or less is not used as a criterion for judgment.
  • the size of 1 bit is several nm, and the flying height of the head is several nm. Even a defect sometimes caused a problem.
  • whether the glass substrate is acceptable or not can be determined based on the number of defects that are difficult to remove by cleaning, regardless of the number of defects that can be easily removed by cleaning. Therefore, the occurrence of such overkill can be suppressed.
  • the inspection method according to the present embodiment includes, in addition to each of the above steps, a step of attaching a label for identifying the glass substrate, a step of associating the determination result in the determination step with the label. It is preferable.
  • the step of attaching a label for identifying the glass substrate is not particularly limited.
  • any method may be used as long as a label for identifying the glass substrate is attached.
  • laser marking that irradiates the glass substrate with a laser beam to attach the label, or scratches on the glass substrate. Is mentioned. Of these, laser marking is preferred because it produces less chipping dust and debris.
  • the position where the mark is attached is outside the area which becomes the recording surface when the information recording medium is obtained.
  • a non-recording area that does not become a recording surface, such as an inner peripheral end face, an outer peripheral end face, and an inner peripheral portion, of the glass substrate is preferable.
  • the sign is not particularly limited as long as the glass substrate can be identified. Specifically, numbers, marks, bar codes, and the like can be given.
  • the step of associating the determination result in the determination step with the label is a step in which the determination result obtained in the determination step is a determination result of which glass substrate is the determination result.
  • the correspondence relationship may be stored by an inspection apparatus for performing the inspection method according to the present embodiment.
  • the glass substrate may be individually separated based on the determination result in the determination step, such as recording the position of the transfer cassette used in the process of performing the inspection each time.
  • the management of the above can more accurately manage the information of the defects existing on the surface of the glass substrate. That is, the information on the defect existing on the surface of the glass substrate can be managed more accurately by associating the determination result with the label attached in advance.
  • the surface of the glass substrate to be inspected may be one side or both sides.
  • the determination step determines that one surface is acceptable and the other surface is unacceptable, it may include a step of associating information as a single-sided acceptable product with the label.
  • Good Such a process should just associate the information as a single-sided pass product with the said label
  • it can be managed as a single-sided acceptable product.
  • information on which surface is acceptable can be managed accurately.
  • This single-sided acceptable product can be used to manufacture an information recording medium that uses only one side as a recording surface.
  • This single-sided acceptable product can be used for manufacturing an information recording medium that uses only one side as a recording surface.
  • the manufacturing method of the glass substrate for information recording media includes, for example, a disk processing step, a heat treatment step (annealing step), a grinding step (lapping step), an inner / outer polishing step, an end surface polishing step, a chemical strengthening step, a polishing step (polishing step), A method including a cleaning step (post-polishing cleaning step), an inspection step, and the like can be given. And each of the above steps may be performed in this order, all of these steps may not be performed, or a method including other steps may be used. For example, a method that does not perform the grinding step or a method that performs the chemical strengthening step after the polishing step may be used. Moreover, you may perform a chemical strengthening process in the middle of a grinding
  • the polishing process includes a rough polishing process, a first precision polishing process, and a second precision polishing process, and a chemical strengthening process is performed between the first precision polishing process and the second precision polishing process.
  • a chemical strengthening process is performed between the first precision polishing process and the second precision polishing process.
  • the manufacturing method includes a polishing step for polishing a plurality of glass substrates, a post-polishing cleaning step for cleaning the surfaces of the plurality of glass substrates after the polishing step, and a post-polishing cleaning step. Thereafter, a part of the plurality of glass substrates is extracted, and a sampling inspection step for inspecting the extracted glass substrate is provided, and the sampling inspection step is a manufacturing method of a glass substrate for an information recording medium according to the inspection method described above. Is the method. According to such a manufacturing method, as described above, a glass substrate for an information recording medium with few defects that is difficult to remove by cleaning can be manufactured.
  • the obtained glass substrate is removed by performing the polishing process or the post-polishing cleaning process under the same conditions as the glass substrate.
  • the polishing process or the post-polishing cleaning process under the same conditions as the glass substrate.
  • the polishing step is not particularly limited as long as it is a polishing step in the method for producing a glass substrate for information recording medium.
  • the polishing step may be a single polishing, but may be a step of performing a plurality of steps of a rough polishing step and a precision polishing step, for example.
  • the precision polishing step may be performed once but may be performed twice or more. Specifically, for example, the following polishing step can be mentioned.
  • the rough polishing step is a step of performing rough polishing on the surface of the glass base plate that is a raw material of the glass substrate. For example, it is a step of rough polishing the surface of a glass base plate that has been subjected to a lapping step, which will be described later, or a glass base plate obtained by molding. This rough polishing is intended to remove scratches and distortions, and is performed using a polishing apparatus described later.
  • the surface to be polished in the rough polishing step is a surface parallel to the surface direction of the glass base plate, that is, the main surface.
  • the polishing apparatus used in the rough polishing step is not particularly limited as long as it is a polishing apparatus used for manufacturing a glass substrate. Specifically, there is a polishing apparatus 11 as shown in FIG. FIG. 2 is a schematic cross-sectional view showing an example of a polishing apparatus used in a polishing step in the method for manufacturing a glass substrate for information recording medium according to the present embodiment.
  • a polishing apparatus 11 as shown in FIG. 2 is an apparatus capable of simultaneously polishing both surfaces of the main surface of a glass base plate.
  • the polishing apparatus 11 includes an apparatus main body 11a and a polishing liquid supply unit 11b that supplies a polishing liquid (polishing slurry) to the apparatus main body 11a.
  • the apparatus main body 11a includes two surface plates 12 and 13 arranged to face each other.
  • the positional relationship between the respective surface plates is not limited to the upper and lower sides.
  • the surface plate disposed on the upper side is the upper surface plate 12, and the surface plate disposed on the lower side is This is referred to as the lower surface plate 13.
  • the apparatus main body 11a includes a disk-shaped upper surface plate 12 and a disk-shaped lower surface plate 13, and they are arranged at an interval in the vertical direction so that they are parallel to each other. Then, the disk-shaped upper surface plate 12 and the disk-shaped lower surface plate 13 rotate in directions opposite to each other.
  • a polishing pad 15 for polishing both the front and back surfaces of the glass base plate 10 is attached to each surface of the disk-shaped upper surface plate 12 and the disk-shaped lower surface plate 13 facing each other.
  • a plurality of rotatable carriers 14 are provided between the disk-shaped upper surface plate 12 and the disk-shaped lower surface plate 13.
  • the carrier 14 is formed with a plurality of base plate holding holes 51, and the glass base plate 10 can be fitted into the base plate holding holes 51 and disposed.
  • 100 base plate holding holes 51 may be formed, and 100 glass base plates 10 may be fitted and arranged. If it does so, 100 glass base plates can be processed by one process (1 batch).
  • the carrier 14 sandwiched between the surface plates 12 and 13 through the polishing pad 15 is the same as the lower surface plate 13 with respect to the center of rotation of the surface plates 12 and 13 while rotating while holding the glass base plate 10. Revolve in the direction.
  • the disk-shaped upper surface plate 12 and the disk-shaped lower surface plate 13 can be operated by separate driving.
  • the polishing liquid 16 is supplied between the upper surface plate 12 and the glass base plate 10 and between the lower surface plate 13 and the glass base plate 10, respectively.
  • the glass base plate 10 can be polished.
  • the polishing liquid supply unit 11b includes a liquid storage unit 110 and a liquid recovery unit 120.
  • the liquid reservoir 110 includes a liquid reservoir main body 110a and a liquid supply pipe 110b having a discharge port 110e extending from the liquid reservoir main body 110a to the apparatus main body 11a.
  • the liquid recovery part 120 was extended from the liquid recovery part main body 120a, the liquid recovery pipe 120b extended from the liquid recovery part main body 120a to the apparatus main body 11a, and from the liquid recovery part main body 120a to the polishing liquid supply part 11b.
  • a liquid return pipe 120c was extended from the liquid recovery part main body 120a, the liquid recovery pipe 120b extended from the liquid recovery part main body 120a to the apparatus main body 11a, and from the liquid recovery part main body 120a to the polishing liquid supply part 11b.
  • a liquid return pipe 120c was extended from the liquid recovery part main body 120a, the liquid recovery pipe 120b extended from the liquid recovery part main body 120a to the apparatus main body 11a, and from the liquid recovery part main body 120a
  • the polishing liquid 16 put in the liquid storage unit main body 110a is supplied from the discharge port 110e of the liquid supply pipe 110b to the apparatus main body part 11a, and from the apparatus main body part 11a through the liquid recovery pipe 120b, the liquid recovery part main body 120a.
  • the recovered polishing liquid 16 is returned to the liquid storage part 110 via the liquid return pipe 120c, and can be supplied again to the apparatus main body part 11a.
  • the polishing pad used here is not particularly limited as long as it can be used in the rough polishing step. Specifically, a hard polishing pad or the like can be used.
  • the polishing liquid used here is a liquid in which an abrasive is dispersed in water, that is, a slurry liquid.
  • a polishing agent for example, a polishing agent containing CeO 2 and the like.
  • an inexpensive Zr-based abrasive can be used for the Ce-based abrasive. Specific examples include ZrO 2 and ZrSiO 4 . These Zr-based materials tend to generate scratches with respect to Ce-based abrasives, so there is a demerit that minute Pits with a size of 1 ⁇ m or less are likely to occur when the polishing amount in the precision polishing process is insufficient. Cheaper than abrasives.
  • the precision polishing step finishes a smooth mirror surface having a surface roughness (Rmax) of about 0.3 nm or less, for example, while maintaining the flat and smooth main surface obtained in the rough polishing step.
  • This precision polishing step is performed, for example, by using a polishing apparatus similar to that used in the rough polishing step and replacing the polishing pad from a hard polishing pad to a soft polishing pad.
  • the surface to be polished in the precision polishing step is the main surface, similar to the surface to be polished in the rough polishing step.
  • a soft polishing pad a suede pad etc. are mentioned, for example.
  • the suede pad is a suede type soft foamed resin pad whose surface (polishing layer) is made of a soft foamed resin such as soft foamed polyurethane.
  • the suede pad is a polishing pad in which bubbles are open to the surface (pad surface), and there are relatively many soft walls separating the bubbles.
  • abrasive used in the precision polishing process an abrasive that causes less scratching even if the polishing performance is lower than that used in the rough polishing process is used.
  • a polishing agent containing silica-based abrasive grains having a particle diameter lower than that of the polishing agent used in the rough polishing step.
  • the average particle diameter of the silica-based abrasive is preferably about 20 nm.
  • polishing agent containing this colloidal silica is used.
  • a polishing liquid (slurry liquid) containing the abrasive is supplied to the glass base plate, and the surface of the glass base plate is mirror-polished by sliding the polishing pad and the glass base plate relatively.
  • the slurry liquid may be circulated and used by the polishing liquid supply unit 11b of the polishing apparatus 11, for example.
  • the glass scrap generated by polishing is mixed with the recovered polishing liquid as in the rough polishing step, so a filter (not shown) is provided in the liquid recovery unit 120 to remove the glass scrap. It is preferable from the viewpoint of reducing scratches generated on the surface.
  • the polishing step is performed by appropriately changing the polishing conditions.
  • polishing process changes grinding
  • the polishing conditions are increased by increasing the polishing pressure or changing to a polishing liquid having high polishing performance.
  • the post-polishing cleaning step is a step of cleaning the glass base plate that has been subjected to the polishing step.
  • polished glass base plate are mentioned.
  • the cleaning process is not particularly limited. Specifically, for example, the following washing steps are mentioned.
  • the glass substrate is washed with an alkaline detergent having a pH of 13 or more, and the glass substrate is rinsed.
  • the glass substrate is washed with an acid detergent having a pH of 1 or less, and the glass substrate is rinsed.
  • the glass substrate is cleaned using a hydrofluoric acid (HF) solution.
  • HF hydrofluoric acid
  • cerium oxide it is most efficient to perform cleaning in the order of alkali cleaning, acid cleaning, and HF cleaning.
  • the abrasive is dispersed and removed with an alkaline detergent, then the abrasive is dissolved and removed with an acid detergent, and finally, the glass base plate is etched with HF, and an abrasive that is deeply stuck into the glass base plate is removed. It is removed.
  • the washing step is preferably performed in separate tanks for alkali washing, acid washing, and HF washing. This is because when these washings are performed in a single tank, efficient washing may not be possible. In particular, when the acid detergent and HF are put in the same tank, the etching rate of HF decreases at a place where there is a large amount of abrasive, and therefore there is a tendency that the inside of the substrate cannot be uniformly etched. Moreover, it is preferable to use a rinse tank after each washing. In some cases, a surfactant, a dispersing agent, a chelating agent, a reducing material, and the like may be added to these detergents. Moreover, it is preferable to apply an ultrasonic wave to each washing tank and to use deaerated water for each detergent.
  • the glass substrate is immersed in a cleaning solution containing 1% by mass of HF and 3% by mass of sulfuric acid. At that time, an ultrasonic vibration of 80 kHz is applied to the cleaning liquid. Thereafter, the glass substrate is taken out. And the taken-out glass substrate is immersed in a neutral detergent liquid. At that time, 120 kHz ultrasonic vibration is applied to the neutral detergent solution. Finally, the glass substrate is taken out, rinsed with pure water, and dried IPA.
  • scrub cleaning may be performed after the above cleaning.
  • Scrub cleaning is a wet physical cleaning method in which the scrub member and the glass substrate are relatively moved while the scrub member is pressed against the glass substrate while supplying a cleaning liquid to the surface of the glass substrate. . By doing so, dirt on the surface of the glass substrate can be scraped off.
  • the apparatus for scrub cleaning is not particularly limited as long as it is an apparatus capable of scrub cleaning an information recording medium glass substrate. Specifically, a roll scrub cleaning device in which the scrub member is a cylindrical roll scrub, a cup scrub cleaning device in which the scrub member is a cup type, and the like can be given.
  • the glass substrate is dried.
  • drying method include drying with IPA vapor, spin drying, and hot water drying.
  • the glass substrate in contact with the liquid in order to prevent foreign matter from adhering to the surface of the glass substrate before the cleaning process.
  • the post-polishing cleaning step is performed by appropriately changing the cleaning conditions.
  • the post-polishing cleaning process changes the cleaning conditions based on the result of the sampling inspection process.
  • the sampling inspection process when a defect that is difficult to remove by cleaning is detected, the cleaning condition is made stricter by changing to a cleaning liquid with high cleaning properties or increasing the cleaning time. .
  • the cleaning condition is made stricter by changing to a cleaning liquid with high cleaning properties or increasing the cleaning time. .
  • a final cleaning may be performed thereafter. That is, as described above, the inspection method may be applied after the information recording medium glass substrate is obtained. In this case, the inspection process performed between the first inspection process and the second inspection process may be simpler than the final cleaning, as described above. Further, final cleaning may be performed as an inspection process performed between the first inspection process and the second inspection process, which is cleaning for inspection.
  • the final cleaning is not particularly limited as long as it is the same cleaning as the final cleaning in the method for manufacturing the glass substrate for information recording medium. For example, cleaning with ultrasonic waves can be mentioned.
  • the disk processing step is a step of processing the raw glass into a disk-shaped glass base plate 10 in which a through hole 10a is formed at the center so that the inner periphery and the outer periphery are concentric circles as shown in FIG. is there.
  • a glass melting step in which raw glass is melted in a melting furnace to form molten glass
  • a forming step in which the molten glass is formed into a disc-shaped glass base plate, and the formed disc-shaped glass base plate
  • the coring process which forms the through-hole 10a in the center part of this, and processes to the disk shaped glass base plate 10 as shown in FIG. 3 is provided.
  • FIG. 3 is a top view showing the glass base plate used in the method for manufacturing the glass substrate for information recording medium according to the present embodiment.
  • the glass melting step is not particularly limited as long as raw glass can be melted in a melting furnace to obtain molten glass.
  • the starting glass is not particularly limited, for example, SiO 2, Na 2 O, and soda-lime glass composed mainly of CaO, SiO 2, Al 2 O 3, and R 1 in 2 O (wherein, R 1 is , K, Na, or Li)), aluminosilicate glass, borosilicate glass, Li 2 O—SiO 2 glass, Li 2 O—Al 2 O 3 —SiO 2 Glass, R 2 O—Al 2 O 3 —SiO 2 glass (wherein R 2 represents Mg, Ca, Sr, or Ba).
  • the glass composition is 55 to 75% by mass of SiO 2 , 5 to 18% by mass of Al 2 O 3 , 1 to 10% by mass of Li 2 O, and 3 to 15% by mass of Na 2 O. %, K 2 O is 0.1 to 5% by mass, MgO is 0.1 to 5% by mass, and CaO is 0.1 to 5% by mass.
  • aluminosilicate glass and borosilicate glass are preferable in that they are excellent in impact resistance and vibration resistance.
  • it does not specifically limit as a melting method of raw material glass, Usually, the method of fuse
  • the forming step is not particularly limited as long as the molten glass can be formed into a disk-shaped glass base plate.
  • the press process etc. which form a disk shaped glass base plate by press molding molten glass are mentioned.
  • the forming step is not limited to the pressing step, and may be a step of, for example, cutting a sheet glass formed by a downdraw method or a float method with a grinding stone to produce a disk-shaped glass base plate.
  • the float method is, for example, a method in which a molten liquid obtained by melting a glass material is poured onto molten tin and solidified as it is.
  • the smoothness is high, for example, the arithmetic average roughness Ra is 0.001 ⁇ m.
  • the following mirror surface is provided.
  • a thickness of a glass base plate a 0.95 mm thing is mentioned, for example.
  • the surface roughness of a glass base plate or a glass substrate for example, Ra or Rmax, can be measured using a general surface roughness measuring machine.
  • the coring process is a process of performing a coring process in which a through hole 10a is formed at the center of the disk-shaped glass base plate formed in the forming process.
  • the disk-shaped glass base plate 10 in which the through-hole 10a was formed in the center part as shown in FIG. 3 is obtained.
  • the coring process is not particularly limited as long as it is a drilling process that forms a through hole in the center of the glass base plate.
  • a method of forming a through-hole in the center of the glass base plate by grinding with a core drill having a diamond grindstone or the like in the cutter portion, a cylindrical diamond drill, or the like can be used. By doing so, a through hole is formed in the center of the glass base plate, and an annular glass base plate is obtained in plan view.
  • the outer diameter r1 is 2.5 inches (about 64 mm), 1.8 inches (about 46 mm), 1 inch (about 25 mm), 0.8 inches (about 20 mm), etc., and the thickness is Disc-shaped glass base plates of 2 mm, 1 mm, 0.63 mm, etc. are obtained. Further, when the outer diameter r1 is 2.5 inches (about 64 mm), for example, the inner diameter r2 is processed to 0.8 inches (about 20 mm).
  • the heat treatment step is a step for adjusting the shape of the glass base plate. Specifically, a step of heat-treating the glass base plate by storing the glass base plate in a heating furnace in a state where the glass base plate is placed on a setter for heat-treating the glass substrate is exemplified.
  • the grinding step is a step of processing the glass base plate to a predetermined plate thickness. Specifically, for example, a step of grinding (lapping) both surfaces of the glass base plate can be mentioned. By doing so, the parallelism, flatness and thickness of the glass base plate are adjusted. Further, this lapping step may be performed once or twice or more. For example, when it is performed twice, the parallelism, flatness and thickness of the glass base plate are preliminarily adjusted in the first lapping process (first lapping process), and glass is used in the second lapping process (second lapping process). Finely adjust the parallelism, flatness and thickness of the base plate. Moreover, when performing a grinding process twice, you may perform a 1st lapping process and a 2nd lapping process continuously, but perform the inside-and-outside grinding process mentioned later and an end surface grinding
  • the grinding apparatus used in the grinding process is not particularly limited as long as it can be used as a grinding apparatus used in the grinding process in the method of manufacturing the glass substrate for information recording medium. Specifically, it is the same as the polishing apparatus used in the polishing step, and includes a resin sheet (grinding sheet) using diamond as a fixed abrasive instead of the polishing pad.
  • examples of the first lapping step include a step in which the entire surface of the glass base plate has a substantially uniform surface roughness.
  • examples of the second lapping step include a step in which a glass base plate from which defects such as large undulations, chips and cracks are removed can be obtained.
  • the inner / outer grinding step is a step of grinding the outer peripheral end surface and the inner peripheral end surface of the glass base plate. Specifically, the process etc. which grind the outer peripheral end surface and inner peripheral end surface of a glass base plate with grinding wheels, such as a drum-shaped diamond grindstone, are mentioned.
  • the end surface polishing step is a step of polishing the outer peripheral end surface and the inner peripheral end surface of the glass base plate. Specifically, a plurality of glass base plates subjected to the inner and outer grinding steps, for example, about 100, are stacked and laminated, and in this state, the outer peripheral end surface and the inner peripheral end surface are polished using an end surface polishing machine. And the like.
  • the chemical strengthening step is not particularly limited, and specific examples include a step of immersing a glass base plate in a chemical strengthening solution (strengthening treatment solution) to form a chemical strengthening layer on the glass base plate.
  • a chemical strengthening layer can be formed in the surface of a glass base plate, for example, a 5 micrometer area
  • a chemical strengthening layer impact resistance, vibration resistance, heat resistance, etc. can be improved.
  • alkali metal ions such as lithium ions and sodium ions contained in the glass base plate are potassium having a larger ion radius. It is carried out by an ion exchange method for substituting alkali metal ions such as ions. Due to the strain caused by the difference in ion radius, compressive stress is generated in the ion-exchanged region, and the surface of the glass base plate is strengthened. That is, it is considered that the reinforcing layer is suitably formed on the glass base plate by this chemical strengthening step.
  • the chemical strengthening treatment solution is not particularly limited as long as it is a chemical strengthening treatment solution used in the chemical strengthening step in the method for producing a glass substrate for a magnetic information recording medium.
  • a melt containing potassium ions a melt containing potassium ions and sodium ions, and the like can be given.
  • melts obtained by melting potassium nitrate, sodium nitrate, potassium carbonate, sodium carbonate, and the like examples include melts obtained by melting potassium nitrate, sodium nitrate, potassium carbonate, sodium carbonate, and the like.
  • a melt obtained by melting potassium nitrate and a melt obtained by melting sodium nitrate are preferably mixed in approximately the same amount.
  • a cleaning step other than the above-described post-polishing cleaning step may be appropriately performed after each step.
  • FIG. 4 is a process diagram showing an example of a method for producing a glass substrate for an information recording medium according to an embodiment of the present invention.
  • a glass substrate (glass base plate) before polishing is prepared. That is, the glass substrate which performed the process before a grinding
  • the glass substrate is polished as described above. Thereafter, post-polishing cleaning is performed as a post-polishing cleaning step. At that time, scrub cleaning is also performed. Then, the first surface inspection is performed. This surface inspection corresponds to the first inspection step and is shown as surface inspection 1 in FIG. Thereafter, final cleaning is performed on the glass substrate subjected to the surface inspection. Thereafter, the surface inspection is performed again. This surface inspection corresponds to the second inspection step and is shown as surface inspection 2 in FIG. The result of the first surface inspection is compared with the result of the second surface inspection, and the pass / fail of the glass substrate is determined based on the number of defects whose positional information has not changed. And the glass substrate which passed is shipped.
  • Such a method for producing a glass substrate for an information recording medium can produce a glass substrate for an information recording medium with few defects that is difficult to remove by washing, as described above.
  • FIG. 5 is a process diagram showing another example of the method for manufacturing the glass substrate for information recording medium according to the embodiment of the present invention.
  • a glass substrate (glass base plate) before polishing is prepared. And as a grinding
  • the glass substrate subjected to the surface inspection is subjected to inspection cleaning for simpler inspection than the final cleaning. Thereafter, the surface inspection is performed again.
  • This surface inspection corresponds to the second inspection step and is shown as surface inspection 2 in FIG.
  • the result of the first surface inspection is compared with the result of the second surface inspection, and the pass / fail of the glass substrate is determined based on the number of defects whose positional information has not changed. And the glass substrate which passed is shipped.
  • Such a method for producing a glass substrate for an information recording medium can produce a glass substrate for an information recording medium with few defects that is difficult to remove by washing, as described above. Thus, it can test
  • FIG. 6 is a process diagram showing an example of a method for producing a glass substrate for an information recording medium for comparison with an embodiment of the present invention.
  • This manufacturing method is a conventional manufacturing method that does not apply the inspection method according to the present embodiment.
  • a glass substrate (glass base plate) before polishing is prepared.
  • polishing process the above grinding
  • post-polishing cleaning is performed as a post-polishing cleaning step.
  • scrub cleaning is also performed.
  • final cleaning is performed.
  • the glass substrate that has been subjected to the final cleaning that is, the finished product as the information recording medium glass substrate may be inspected.
  • surface inspection is performed on a glass substrate that has been subjected to final cleaning. The pass / fail of the glass substrate is determined based on the number and size of defects obtained by the surface inspection. And the glass substrate which passed is shipped.
  • the pass / fail of the glass substrate is determined including defects that can be easily removed by cleaning. For this reason, if the judgment criteria are loosened, defects in the obtained glass substrate increase. On the other hand, if the judgment criteria are strict, even those that are rejected may be in a state where there are few defects that are difficult to remove by cleaning.
  • FIG. 7 is a partial cross-sectional perspective view showing a magnetic disk as an example of a magnetic recording medium using the glass substrate for information recording medium manufactured by the method for manufacturing the glass substrate for information recording medium according to the present embodiment.
  • This magnetic disk D includes a magnetic film 102 formed on the main surface of a circular glass substrate 101 for an information recording medium. For the formation of the magnetic film 102, a known method is used.
  • a formation method for forming the magnetic film 102 by spin-coating a thermosetting resin in which magnetic particles are dispersed on the glass substrate 101 for information recording medium
  • examples thereof include a forming method for forming the magnetic film 102 by sputtering (sputtering method) and a forming method for forming the magnetic film 102 on the glass substrate 101 for information recording medium by electroless plating (electroless plating method).
  • the thickness of the magnetic film 102 is about 0.3 to 1.2 ⁇ m in the case of the spin coating method, and about 0.04 to 0.08 ⁇ m in the case of the sputtering method, and is based on the electroless plating method. In some cases, the thickness is about 0.05 to 0.1 ⁇ m. From the viewpoint of thinning and densification, film formation by sputtering is preferable, and film formation by electroless plating is preferable.
  • the magnetic material used for the magnetic film 102 can be any known material and is not particularly limited.
  • the magnetic material is preferably, for example, a Co-based alloy based on Co having high crystal anisotropy in order to obtain a high coercive force, and Ni or Cr added for the purpose of adjusting the residual magnetic flux density. More specifically, CoPt, CoCr, CoNi, CoNiCr, CoCrTa, CoPtCr, CoNiPt, CoNiCrPt, CoNiCrTa, CoCrPtB, CoCrPtSiO, and the like whose main component is Co can be given.
  • the magnetic film 102 has a multilayer structure (for example, CoPtCr / CrMo / CoPtCr, CoCrPtTa / CrMo / CoCrPtTa, etc.) divided by a nonmagnetic film (for example, Cr, CrMo, CrV, etc.) in order to reduce noise.
  • a multilayer structure for example, CoPtCr / CrMo / CoPtCr, CoCrPtTa / CrMo / CoCrPtTa, etc.
  • ferrite or iron - may be a rare earth, also, Fe in a non-magnetic film made of SiO 2, BN, etc., Co, FeCo, CoNiPt and the like
  • a granular material having a structure in which the magnetic particles are dispersed may be used.
  • either an inner surface type or a vertical type recording format may be used for recording on the magnetic film 102.
  • the surface of the magnetic film 102 may be thinly coated with a lubricant.
  • a lubricant include those obtained by diluting perfluoropolyether (PFPE), which is a liquid lubricant, with a freon-based solvent.
  • an underlayer or a protective layer may be provided on the magnetic film 102 as necessary.
  • the underlayer in the magnetic disk D is appropriately selected according to the magnetic film 102.
  • the material for the underlayer include at least one material selected from nonmagnetic metals such as Cr, Mo, Ta, Ti, W, V, B, Al, and Ni.
  • the material of the underlayer is preferably Cr alone or a Cr alloy from the viewpoint of improving magnetic characteristics.
  • the underlayer is not limited to a single layer, and may have a multilayer structure in which the same or different layers are stacked.
  • Examples of such an underlayer having a multilayer structure include multilayer underlayers such as Cr / Cr, Cr / CrMo, Cr / CrV, NiAl / Cr, NiAl / CrMo, and NiAl / CrV.
  • Examples of the protective layer that prevents wear and corrosion of the magnetic film 102 include a Cr layer, a Cr alloy layer, a carbon layer, a hydrogenated carbon layer, a zirconia layer, and a silica layer. These protective layers can be continuously formed with the underlayer and the magnetic film 102 by an in-line sputtering apparatus. These protective layers may be a single layer, or may be a multi-layer structure composed of the same or different layers.
  • a SiO 2 layer may be formed on the Cr layer.
  • Such a SiO 2 layer is formed by dispersing and applying colloidal silica fine particles in a tetraalkoxysilane diluted with an alcohol-based solvent on the Cr layer and further baking.
  • the information recording medium glass substrate 101 is formed with the above-described composition. Can be done by sex.
  • the glass substrate 101 for information recording media in this embodiment was used for a magnetic recording medium (magnetic disk) was demonstrated above, it is not limited to this, for information recording media in this embodiment
  • the glass substrate 101 can also be used for magneto-optical disks, optical disks, and the like.
  • One aspect of the present invention is to detect a defect present on the surface of the glass substrate and obtain positional information of the defect, and after the first inspection step, clean the surface of the glass substrate.
  • a glass substrate inspection method for an information recording medium comprising: a determination step of determining pass / fail of the glass substrate on the basis of the number of coincident positions of defect positions acquired in the second inspection step.
  • the position information of the defect acquired in the second inspection process matches the position information in the first inspection process acquired in advance before cleaning in the cleaning process.
  • the acceptance / rejection of the glass substrate is determined based on the number. This is considered to mean that the number used for the determination is the number of defects that did not move in the cleaning process.
  • the defects that have not moved in the cleaning process are considered to be the number of defects that are difficult to remove by cleaning.
  • the defect detected in the second inspection step and the defect position information acquired in the first inspection step and the defect position information acquired in the second inspection step do not coincide with each other. In the process, it is a defect such as a foreign matter defect that has been reattached and is considered to be a defect that can be removed by washing again.
  • the glass substrate is determined by determining whether the glass substrate is acceptable or not based on the above criteria. Pass / fail can be determined.
  • the first inspection step and the second inspection step irradiate the glass substrate with inspection light, and based on reflected light and scattered light of the inspection light, It is preferable to detect defects.
  • the defect can be detected by a simple method. Therefore, it is possible to accurately and easily perform defects that are difficult to remove by cleaning.
  • the method for inspecting the glass substrate for information recording medium it is preferable to include a step of attaching a label for identifying the glass substrate, a step of associating the determination result in the determination step with the label.
  • the method includes a step of associating the information with the label.
  • Another aspect of the present invention is a polishing step for polishing a plurality of glass substrates, a post-polishing cleaning step for cleaning the surfaces of the plurality of glass substrates after the polishing step, and the post-polishing cleaning.
  • a glass substrate for an information recording medium with few defects that is difficult to remove by cleaning can be manufactured. Specifically, when it is determined to be unacceptable in the sampling inspection process, the obtained glass substrate is removed by performing the polishing process or the post-polishing cleaning process under the same conditions as the glass substrate. Thus, a glass substrate for an information recording medium with few defects that cannot be easily removed by washing can be obtained.
  • the polishing step changes polishing conditions based on a result in the sampling inspection step.
  • the polishing conditions of the polishing step can be changed based on the determination result in the sampling inspection step, a glass substrate for an information recording medium with few defects that is difficult to remove by cleaning is obtained.
  • the frequency which can be manufactured can be raised.
  • the post-polishing cleaning step changes the cleaning conditions based on the result of the sampling inspection step.
  • the cleaning conditions of the post-polishing cleaning step can be changed based on the determination result in the sampling inspection step, the glass for information recording media with few defects that is difficult to remove by cleaning.
  • the frequency with which the substrate can be manufactured can be increased.
  • a method for inspecting a glass substrate for an information recording medium capable of accurately detecting defects that are difficult to remove by cleaning is provided.
  • inspection method is provided.

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Abstract

An aspect of the present invention is a method for inspecting a glass substrate for an information storage medium, the method being provided with: a first inspection step for detecting defects existing on the surface of the glass substrate, and acquiring position information for the defects; a cleaning step after the first inspection step, for cleaning the surface of the glass substrate; a second inspection step after the cleaning step, for detecting defects existing on the surface of the glass substrate and acquiring position information for the defects; an assessment step for assessing the passing status of the glass substrate on the basis of the number of instances where the position information for defects acquired in the first inspection step and the position information for defects acquired in the second inspection step are consistent.

Description

情報記録媒体用ガラス基板の検査方法、及び情報記録媒体用ガラス基板の製造方法Method for inspecting glass substrate for information recording medium, and method for manufacturing glass substrate for information recording medium
　本発明は、情報記録媒体用ガラス基板の検査方法、及び情報記録媒体用ガラス基板の製造方法に関する。 The present invention relates to a method for inspecting a glass substrate for information recording medium and a method for manufacturing a glass substrate for information recording medium.
　磁気、光及び光磁気等を利用することによって、情報を情報記録媒体に記録する情報記録装置が知られている。このような情報記録装置としては、代表的なものとして、例えば、ハードディスクドライブ装置等が挙げられる。ハードディスクドライブ装置は、基板上に記録層を形成した情報記録媒体としての磁気ディスク（ハードディスク）に、磁気ヘッドによって磁気的に情報を記録し（書き込み）、記録した情報を再生する（読み出す）装置である。このような情報記録媒体の基材、いわゆるサブストレートとしては、ガラス基板が好適に用いられている。 2. Description of the Related Art Information recording apparatuses that record information on an information recording medium by using magnetism, light, photomagnetism, or the like are known. A typical example of such an information recording apparatus is a hard disk drive apparatus. A hard disk drive device is a device that magnetically records (writes) information on a magnetic disk (hard disk) as an information recording medium having a recording layer formed on a substrate, and reproduces (reads) the recorded information. is there. As a base material of such an information recording medium, a so-called substrate, a glass substrate is preferably used.
　また、ハードディスクドライブ装置は、磁気ディスクに情報を記録したり、読み出したりする際、磁気ヘッドを磁気ディスクに接触することなく、磁気ディスクに対し浮上させておくものである。そして、磁気ヘッドの浮上量を低減させることによって、記録密度の向上が図れることが知られている。近年は、垂直磁気記録方式による磁気ディスクの記録密度の高密度化が図られ、磁気ヘッドの浮上量が数ｎｍ程度にまで減少している。このため、情報記録媒体にガラス基板の異物欠陥等に基づく欠陥があると、前記磁気ヘッドの浮上が不安定になり、磁気ヘッドと磁気ディスクとが衝突してしまう、いわゆるヘッドクラッシュとよばれる現象が発生することがある。また、ヘッドクラッシュを起こさない場合であっても、磁気ヘッドの浮上安定性に影響することがある。これらのことから、磁気ヘッドの浮上量をより低減させて、記録密度をより高めるためには、情報記録媒体用ガラス基板に欠陥が少ないこと等が求められる。このため、情報記録媒体用ガラス基板の、欠陥の数や大きさ等を検査する欠陥検査が、重要になってきている。 In addition, the hard disk drive device floats the magnetic head with respect to the magnetic disk without contacting the magnetic disk when information is recorded on or read from the magnetic disk. It is known that the recording density can be improved by reducing the flying height of the magnetic head. In recent years, the recording density of a magnetic disk by the perpendicular magnetic recording system has been increased, and the flying height of the magnetic head has been reduced to about several nanometers. For this reason, if the information recording medium has a defect based on a foreign substance defect on the glass substrate, the flying of the magnetic head becomes unstable and the magnetic head and the magnetic disk collide with each other, so-called a head crash phenomenon. May occur. Even when the head does not crash, it may affect the flying stability of the magnetic head. For these reasons, in order to further reduce the flying height of the magnetic head and increase the recording density, it is required that the glass substrate for information recording medium has few defects. For this reason, defect inspection for inspecting the number and size of defects of the glass substrate for information recording media has become important.
　そこで、異物欠陥等の欠陥を検査する方法としては、例えば、特許文献１に記載の方法等が挙げられる。 Therefore, as a method for inspecting defects such as foreign matter defects, for example, the method described in Patent Document 1 can be cited.
　特許文献１には、製造された磁気ディスク用ガラス基板を検査する検査工程を含む磁気ディスク用ガラス基板の製造方法であって、前記検査工程において、前記磁気ディスク用ガラス基板上の欠陥の大きさと数とで決められた複数の判定基準に基づいて磁気ディスク用ガラス基板の合否を判定する磁気ディスク用ガラス基板の製造方法が記載されている。特許文献１によれば、欠陥の個数のみで良否判定を行う場合よりも精度の良い判定が可能となることが開示されている。 Patent Document 1 discloses a method of manufacturing a magnetic disk glass substrate including an inspection process for inspecting the manufactured magnetic disk glass substrate, wherein in the inspection process, the size of the defect on the magnetic disk glass substrate is determined. A method for manufacturing a glass substrate for magnetic disk is described which determines pass / fail of a glass substrate for magnetic disk based on a plurality of determination criteria determined by the number. According to Patent Document 1, it is disclosed that it is possible to make a determination with higher accuracy than in the case where the pass / fail determination is performed only by the number of defects.
特開２０１０－７３２４３号公報JP 2010-73243 A
　本発明は、洗浄で除去が困難な欠陥を精度良く検出できる情報記録媒体用ガラス基板の検査方法を提供することを目的とする。また、本発明は、この検査方法を用いた情報記録媒体用ガラス基板の製造方法を提供することを目的とする。 An object of the present invention is to provide a method for inspecting a glass substrate for an information recording medium capable of accurately detecting defects that are difficult to remove by cleaning. Moreover, this invention aims at providing the manufacturing method of the glass substrate for information recording media which used this test | inspection method.
　本発明の一局面は、前記ガラス基板の表面に存在する欠陥を検出し、前記欠陥の位置情報を取得する第１検査工程と、前記第１検査工程の後に、前記ガラス基板の表面を洗浄する洗浄工程と、前記洗浄工程の後に、前記ガラス基板の表面に存在する欠陥を検出し、前記欠陥の位置情報を取得する第２検査工程と、前記第１検査工程で取得した欠陥の位置情報と、前記第２検査工程で取得した欠陥の位置情報とが一致している個数に基づいて、前記ガラス基板の合否を判定する判定工程とを備える情報記録媒体用ガラス基板の検査方法である。 One aspect of the present invention is to detect a defect present on the surface of the glass substrate and obtain positional information of the defect, and after the first inspection step, clean the surface of the glass substrate. A cleaning step, a second inspection step for detecting defects present on the surface of the glass substrate after the cleaning step, and acquiring positional information of the defects; and positional information of the defects acquired in the first inspection step; And a glass substrate inspection method for an information recording medium, comprising: a determination step of determining pass / fail of the glass substrate on the basis of the number of coincident positions of defect positions acquired in the second inspection step.
　また、本発明の他の一局面は、複数枚のガラス基板を研磨する研磨工程と、前記研磨工程の後に、前記複数枚のガラス基板の表面を洗浄する研磨後洗浄工程と、前記研磨後洗浄工程の後に、前記複数枚のガラス基板のうちの一部を抜き取り、抜き取ったガラス基板を検査する抜き取り検査工程とを備え、前記抜き取り検査工程が、前記検査方法である情報記録媒体用ガラス基板の製造方法である。 Another aspect of the present invention is a polishing step for polishing a plurality of glass substrates, a post-polishing cleaning step for cleaning the surfaces of the plurality of glass substrates after the polishing step, and the post-polishing cleaning. A step of extracting a part of the plurality of glass substrates after the step, and a sampling inspection step of inspecting the extracted glass substrate, wherein the sampling inspection step of the glass substrate for information recording medium is the inspection method; It is a manufacturing method.
　本発明の目的、特徴、局面、及び利点は、以下の詳細な記載と添付図面とによって、より明白となる。 The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.
図１は、本発明の実施形態に係る検査方法を説明するための図面である。FIG. 1 is a drawing for explaining an inspection method according to an embodiment of the present invention. 図２は、本発明の実施形態に係る情報記録媒体用ガラス基板の製造方法における研磨工程で用いる研磨装置の一例を示す概略断面図である。FIG. 2 is a schematic cross-sectional view showing an example of a polishing apparatus used in a polishing step in the method for manufacturing a glass substrate for information recording medium according to the embodiment of the present invention. 図３は、本発明の実施形態に係る情報記録媒体用ガラス基板の製造方法で用いられるガラス素板を示す上面図である。FIG. 3 is a top view showing a glass base plate used in the method for manufacturing a glass substrate for information recording medium according to the embodiment of the present invention. 図４は、本発明の実施形態に係る情報記録媒体用ガラス基板の製造方法の一例を示す工程図である。FIG. 4 is a process diagram showing an example of a method for producing a glass substrate for information recording media according to an embodiment of the present invention. 図５は、本発明の実施形態に係る情報記録媒体用ガラス基板の製造方法の他の一例を示す工程図である。FIG. 5 is a process diagram showing another example of the method for manufacturing the glass substrate for information recording medium according to the embodiment of the present invention. 図６は、本発明の実施形態と比較するための情報記録媒体用ガラス基板の製造方法の一例を示す工程図である。FIG. 6 is a process diagram showing an example of a method for producing a glass substrate for an information recording medium for comparison with an embodiment of the present invention. 図７は、本実施形態に係る情報記録媒体用ガラス基板の製造方法により製造された情報記録媒体用ガラス基板を用いた磁気記録媒体の一例である磁気ディスクを示す一部断面斜視図である。FIG. 7 is a partial cross-sectional perspective view showing a magnetic disk as an example of a magnetic recording medium using the glass substrate for information recording medium manufactured by the method for manufacturing the glass substrate for information recording medium according to the present embodiment.
　本発明者等の検討によれば、特許文献１に記載の方法のような、欠陥の大きさと数とに基づく判定では、欠陥の判定として不充分な場合があった。すなわち、このような判定では、判定基準が低いと、不良品を充分に排除することができず、また、判定基準を高めると、本来合格品にすべきものを不良品として判定して排除してしまう、いわゆる、オーバーキルが発生することがわかった。 According to the study by the present inventors, the determination based on the size and number of defects as in the method described in Patent Document 1 may not be sufficient as a defect determination. That is, in such a determination, if the determination criterion is low, defective products cannot be sufficiently excluded, and if the determination criterion is increased, what should be originally passed is determined as a defective product and eliminated. It was found that so-called overkill occurs.
　具体的には、ハードディスク等の情報記録媒体を製造するために、ガラス基板を用いる際には、スパッタリング等を行う前に、ガラス基板の表面を洗浄する。そして、ガラス基板の欠陥としては、この洗浄で除去が容易なものと、除去が困難なものとがある。上記の判定では、判定された欠陥が、除去可能な欠陥であっても、その欠陥が大きかったり、その数が多かったりすると、不良品と判定される。しかしながら、このような欠陥は、情報記録媒体の製造時の洗浄で除去できるので、不良品と判定したものの中には、本来合格品にすべきものである場合がある。 Specifically, when a glass substrate is used to manufacture an information recording medium such as a hard disk, the surface of the glass substrate is cleaned before performing sputtering or the like. And as a defect of a glass substrate, there exists a thing with easy removal by this washing | cleaning, and a thing with difficult removal. In the above determination, even if the determined defect is a removable defect, if the defect is large or the number thereof is large, it is determined as a defective product. However, since such a defect can be removed by washing at the time of manufacturing the information recording medium, some of the products determined to be defective may originally be acceptable products.
　本発明は、かかる事情から鑑みたものであって、洗浄で除去が困難な欠陥を精度良く検出できる情報記録媒体用ガラス基板の検査方法を提供することを目的とする。また、本発明は、この検査方法を用いた情報記録媒体用ガラス基板の製造方法を提供することを目的とする。 The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for inspecting a glass substrate for an information recording medium that can accurately detect defects that are difficult to remove by cleaning. Moreover, this invention aims at providing the manufacturing method of the glass substrate for information recording media which used this test | inspection method.
　そこで、本発明者等は、種々検討した結果、上記目的は、後述する方法により達成されることを見出し、本発明を完成するに到った。 Therefore, as a result of various studies, the present inventors have found that the above object can be achieved by a method described later, and have completed the present invention.
　以下、本発明に係る実施形態について説明するが、本発明は、これらに限定されるものではない。 Hereinafter, embodiments according to the present invention will be described, but the present invention is not limited thereto.
　［情報記録媒体用ガラス基板の検査方法］
　本実施形態に係る情報記録媒体用ガラス基板の検査方法は、前記ガラス基板の表面に存在する欠陥を検出し、前記欠陥の位置情報（第１位置情報）を取得する第１検査工程と、前記第１検査工程の後に、前記ガラス基板の表面を洗浄する洗浄工程と、前記洗浄工程の後に、前記ガラス基板の表面に存在する欠陥を検出し、前記欠陥の位置情報（第２位置情報）を取得する第２検査工程と、前記第１位置情報と、前記第２位置情報とが一致している個数に基づいて、前記ガラス基板の合否を判定する判定工程とを備える。 [Inspection method of glass substrate for information recording medium]
The inspection method of the glass substrate for information recording media concerning this embodiment detects the defect which exists in the surface of the glass substrate, and acquires the position information (first position information) of the defect, After the first inspection process, a cleaning process for cleaning the surface of the glass substrate, and after the cleaning process, a defect present on the surface of the glass substrate is detected, and position information (second position information) of the defect is obtained. A second inspection step to be acquired; and a determination step of determining pass / fail of the glass substrate based on the number of the first position information and the second position information that coincide with each other.
　上記検査方法は、前記第２位置情報と、前記洗浄工程での洗浄の前に予め取得しておいた、前記第１位置情報とが一致している個数に基づいて、ガラス基板の合否を判定する方法である。すなわち、本実施形態に係る検査方法における判定工程での判断基準は、前記第１位置情報と前記第２位置情報とが一致する個数である。この判定に用いた個数は、前記洗浄工程で移動しなかった欠陥の個数であると考えられる。そして、この個数は、洗浄で除去が困難な欠陥の個数であると考えられる。このことから、本実施形態に係る検査方法は、洗浄で除去が困難な欠陥の個数に基づいて、ガラス基板の合否を判定することができる。 In the inspection method, the pass / fail of the glass substrate is determined based on the number of the second position information and the first position information that is acquired in advance before cleaning in the cleaning step. It is a method to do. That is, the determination criterion in the determination step in the inspection method according to the present embodiment is the number of the first position information and the second position information that match. The number used for this determination is considered to be the number of defects that did not move in the cleaning step. This number is considered to be the number of defects that are difficult to remove by cleaning. From this, the inspection method according to the present embodiment can determine pass / fail of the glass substrate based on the number of defects that are difficult to remove by cleaning.
　一方、本実施形態に係る検査方法は、前記第２検査工程で検出された欠陥で、前記第１位置情報と前記第２位置情報とが一致しなかった欠陥は、前記洗浄工程において、再付着した異物欠陥等の欠陥であり、再度、洗浄することによって、除去可能な欠陥であるとしたものである。 On the other hand, in the inspection method according to the present embodiment, the defect detected in the second inspection process, and the defect in which the first position information and the second position information do not match is reattached in the cleaning process. The defect is a defect that can be removed by cleaning again.
　以上のことから、本実施形態に係る検査方法は、前記第２検査工程で検出された欠陥の個数ではなく、前記第１位置情報と前記第２位置情報とが一致する個数に基づいて判定するので、洗浄で除去が容易な欠陥の個数にかかわらず、洗浄で除去が困難な欠陥の個数に基づいて、ガラス基板の合否を判定することができる。 From the above, the inspection method according to the present embodiment makes a determination based on the number of coincidence of the first position information and the second position information, not the number of defects detected in the second inspection step. Therefore, regardless of the number of defects that can be easily removed by cleaning, the pass / fail of the glass substrate can be determined based on the number of defects that are difficult to remove by cleaning.
　なお、洗浄で除去が困難な欠陥とは、ガラス基板に対して、洗浄しても、例えば、情報記録媒体を製造する際の、記録層を形成する前に行う洗浄等を施しても、除去不能な欠陥（Ｎｏｎ　Ｒｅｍｏｖａｂｌｅ　Ｄｅｆｅｃｔ：ＮＲＤ）等の、除去が困難な欠陥である。具体的には、後述するような洗浄工程を施しても、移動しない欠陥を指す。より具体的には、ガラス基板に強固に付着した異物欠陥等の、除去不能な欠陥が挙げられる。 Defects that are difficult to remove by washing are removed even if the glass substrate is washed, for example, washed before forming a recording layer when manufacturing an information recording medium. Defects that are difficult to remove, such as non-removable defects (NRD). Specifically, it refers to a defect that does not move even after a cleaning process as described later. More specifically, a defect that cannot be removed, such as a foreign substance defect firmly attached to a glass substrate, can be mentioned.
　まず、本実施形態に係る情報記録媒体用ガラス基板の検査方法による検査対象物であるガラス基板について、説明する。 First, a glass substrate which is an inspection object by the method for inspecting a glass substrate for information recording medium according to the present embodiment will be described.
　検査対象物であるガラス基板は、情報記録媒体用ガラス基板であれば、特に限定されない。例えば、別途製造された情報記録媒体用ガラス基板や、情報記録媒体用ガラス基板を製造する際の最終段階のガラス基板等が挙げられる。すなわち、この検査方法は、別途製造された情報記録媒体用ガラス基板を検査してもよいし、情報記録媒体用ガラス基板を製造する際、最終段階の工程等に適用してもよい。この検査方法を、情報記録媒体用ガラス基板を製造する際の最終段階の工程に適用する場合、詳しくは後述するが、前記洗浄工程が、情報記録媒体用ガラス基板の製造方法における最終洗浄工程であってもよいし、最終洗浄工程後に、別途、検査のために行う洗浄工程であってもよい。また、検査対象物であるガラス基板は、大きさも、特に限定されず、例えば、直径６５ｍｍ、厚さ０．８ｍｍのガラス基板や、直径４８ｍｍ、厚さ０．５ｍｍのガラス基板等が挙げられる。 The glass substrate that is the inspection object is not particularly limited as long as it is a glass substrate for an information recording medium. For example, the glass substrate for information recording media manufactured separately, the glass substrate of the last stage at the time of manufacturing the glass substrate for information recording media, etc. are mentioned. That is, this inspection method may inspect a separately manufactured glass substrate for information recording medium, or may be applied to a final stage process or the like when manufacturing a glass substrate for information recording medium. When this inspection method is applied to the final stage process when manufacturing the glass substrate for information recording medium, the cleaning process is a final cleaning process in the manufacturing method of the glass substrate for information recording medium, which will be described in detail later. There may be a cleaning step that is performed separately for inspection after the final cleaning step. Further, the size of the glass substrate that is an inspection object is not particularly limited, and examples thereof include a glass substrate having a diameter of 65 mm and a thickness of 0.8 mm, a glass substrate having a diameter of 48 mm and a thickness of 0.5 mm, and the like.
　次に、本実施形態に係る情報記録媒体用ガラス基板の検査方法における第１検査工程について、説明する。 Next, the first inspection step in the method for inspecting the glass substrate for information recording medium according to the present embodiment will be described.
　前記第１検査工程は、前記ガラス基板の表面に存在する欠陥を検出し、前記欠陥の位置情報を取得することができる工程であれば、特に限定されない。例えば、ガラス基板の表面に存在する欠陥を検出し、その位置情報を取得することができる検査装置を用いる方法等が挙げられる。また、欠陥を検出する方法としては、特に限定されない。例えば、光学的手段を用いる方法等が挙げられる。具体的には、ガラス基板に検査光を照射し、前記検査光の反射光及び散乱光に基づいて、欠陥の検出を行う方法等が挙げられる。このような方法は、簡便な方法で、欠陥を検出することができる点で好ましい。すなわち、このような方法を、本実施形態に適用することによって、洗浄で除去が困難な欠陥を精度良く、且つ、簡便に行うことができる。また、より具体的には、レーザ散乱による面検査装置（株式会社日立ハイテクノロジーズ製のディスク表面検査装置　ＮＳ７３００Ｒ）を用いて、検査することができる。なお、このような面検査装置は、レーザ光の照射による散乱反射光を観測することで、欠陥の有無、位置、数を測定して、そのサイズや信号の特性によって欠陥を判別するものである。 The first inspection step is not particularly limited as long as it is a step capable of detecting a defect present on the surface of the glass substrate and acquiring positional information of the defect. For example, a method using an inspection apparatus capable of detecting a defect present on the surface of a glass substrate and acquiring position information thereof can be used. Moreover, it does not specifically limit as a method of detecting a defect. For example, a method using optical means can be used. Specifically, a method of irradiating a glass substrate with inspection light and detecting a defect based on reflected light and scattered light of the inspection light can be used. Such a method is preferable in that a defect can be detected by a simple method. That is, by applying such a method to this embodiment, it is possible to accurately and easily perform defects that are difficult to remove by cleaning. More specifically, the inspection can be performed by using a laser scattering surface inspection device (a disk surface inspection device NS7300R manufactured by Hitachi High-Technologies Corporation). Note that such a surface inspection apparatus measures the presence / absence, position, and number of defects by observing scattered / reflected light by laser light irradiation, and discriminates defects by their size and signal characteristics. .
　次に、本実施形態に係る情報記録媒体用ガラス基板の検査方法における洗浄工程について、説明する。 Next, the cleaning process in the method for inspecting the glass substrate for information recording medium according to the present embodiment will be described.
　前記洗浄工程は、ガラス基板の表面を洗浄することができれば、特に限定されない。例えば、上述したように、情報記録媒体用のガラス基板の製造方法における最終洗浄工程等が挙げられる。すなわち、最終洗浄工程と同条件の洗浄が挙げられる。具体的には、洗剤による洗浄や、ガラス基板を洗浄液に浸漬させ、高周波の超音波を印加する超音波洗浄等が挙げられる。これらの洗浄に、さらに、スクラブ洗浄を行ってもよい。前記洗浄工程は、洗浄で除去が容易な欠陥を除去する必要はなく、移動すればよいので、最終洗浄工程より簡易な洗浄であってもよい。具体的には、最終洗浄工程は、通常、上記の洗浄を行う槽を１０槽以上備え、それらを用いて洗浄する工程であるが、本実施形態に係る検査方法における洗浄工程では、５槽程度であってもよい。 The cleaning step is not particularly limited as long as the surface of the glass substrate can be cleaned. For example, as described above, the final cleaning step in the method for producing a glass substrate for an information recording medium can be mentioned. That is, cleaning under the same conditions as in the final cleaning step can be mentioned. Specifically, cleaning with a detergent, ultrasonic cleaning in which a glass substrate is immersed in a cleaning solution, and high-frequency ultrasonic waves are applied can be used. In addition to these cleaning operations, scrub cleaning may be performed. The cleaning process does not need to remove defects that can be easily removed by cleaning, and may be moved more easily. Therefore, the cleaning process may be simpler than the final cleaning process. Specifically, the final cleaning step is usually a step in which 10 or more tanks for performing the above-described cleaning are provided and cleaned using them. In the cleaning process in the inspection method according to the present embodiment, about 5 tanks are used. It may be.
　次に、本実施形態に係る情報記録媒体用ガラス基板の検査方法における第２検査工程について、説明する。 Next, the second inspection step in the method for inspecting the glass substrate for information recording medium according to the present embodiment will be described.
　前記第２検査工程は、前記ガラス基板の表面に存在する欠陥を検出し、前記欠陥の位置情報を取得することができる工程であれば、特に限定されない。本実施形態に係る検査方法では、この第２検査工程での検査結果である第２位置情報と、予め得ていた第１位置情報とを比較して、欠陥の移動の有無を観測しているので、前記第２検査工程は、前記第１検査工程と同様であることが好ましい。 The second inspection step is not particularly limited as long as it is a step capable of detecting a defect present on the surface of the glass substrate and acquiring positional information of the defect. In the inspection method according to the present embodiment, the second position information, which is the inspection result in the second inspection step, is compared with the first position information obtained in advance, and the presence / absence of defect movement is observed. Therefore, it is preferable that the second inspection step is the same as the first inspection step.
　次に、本実施形態に係る情報記録媒体用ガラス基板の検査方法における判定工程について、説明する。 Next, the determination process in the method for inspecting the glass substrate for information recording medium according to the present embodiment will be described.
　前記判定工程は、前記第１位置情報と第２位置情報とが一致している個数に基づいて、ガラス基板の合否を判定する工程であれば、特に限定されない。すなわち、前記第１検査工程及び前記第２検査工程で検出された欠陥の個数にかかわらず、ガラス基板の合否を判定する。前記判定工程は、具体的には、検査装置に記憶された、第１位置情報と第２位置情報とを、検査装置の制御部で照合し、一致した個数を出力すること等によって行うことができる。そして、その個数が、所定の個数以下であれば、合格と判定し、所定の個数を超えれば、不合格と判定する。この基準となる個数は、情報記録媒体用ガラスに求められる品質によっても異なる。例えば、この基準となる個数が、０個である場合、第１位置情報と第２位置情報とが、全く一致しなかった場合、合格とし、１つでも一致すれば、不合格とする。 The determination step is not particularly limited as long as it is a step for determining pass / fail of the glass substrate based on the number of the first position information and the second position information that coincide with each other. That is, whether the glass substrate is acceptable or not is determined regardless of the number of defects detected in the first inspection step and the second inspection step. Specifically, the determination step can be performed by collating the first position information and the second position information stored in the inspection apparatus by the control unit of the inspection apparatus and outputting the number of coincidence. it can. And if the number is below a predetermined number, it will determine with a pass, and if it exceeds a predetermined number, it will determine with a failure. The reference number varies depending on the quality required for the glass for the information recording medium. For example, when the reference number is 0, if the first position information and the second position information do not match at all, the pass is accepted.
　本実施形態に係る検査方法は、上記の構成によって、洗浄で除去が容易な欠陥の個数にかかわらず、洗浄で除去が困難な欠陥の個数に基づいて、ガラス基板の合否を判定することができる。 The inspection method according to the present embodiment can determine pass / fail of the glass substrate based on the number of defects that are difficult to remove by cleaning, regardless of the number of defects that can be easily removed by cleaning, with the above configuration. .
　また、本実施形態に係る検査方法は、具体的には、以下のような検査方法である。 Further, the inspection method according to the present embodiment is specifically the following inspection method.
　図１は、本実施形態に係る検査方法を説明するための図面である。 FIG. 1 is a drawing for explaining an inspection method according to the present embodiment.
　まず、前記第１検査工程では、図１（ａ）に示すように、ガラス基板１の表面に存在する欠陥２を５個検出し、その欠陥２の位置情報をそれぞれ取得する。その後、前記洗浄工程で、ガラス基板の表面を洗浄する。その洗浄後、前記第２検査工程を施す。その結果、図１（ｂ）に示すように、ガラス基板の表面に欠陥３，４が３個検出され、それらの位置情報をそれぞれ取得する。そして、前記判定工程で、位置情報を対比することによって、前記第２検査工程で検出された３個の欠陥は、洗浄工程の前後で、位置情報が一致している欠陥３が２個と、一致しない欠陥４が１個とが含まれることがわかる。本実施形態に係る検査方法では、この一致している欠陥３の個数である２個を判断基準として、ガラス基板１の合否を判定する。 First, in the first inspection step, as shown in FIG. 1A, five defects 2 existing on the surface of the glass substrate 1 are detected, and position information of the defects 2 is acquired. Thereafter, the surface of the glass substrate is cleaned in the cleaning step. After the cleaning, the second inspection process is performed. As a result, as shown in FIG. 1B, three defects 3 and 4 are detected on the surface of the glass substrate, and their positional information is acquired. Then, by comparing the position information in the determination step, the three defects detected in the second inspection step are two defects 3 having the same position information before and after the cleaning step. It can be seen that one defect 4 that does not match is included. In the inspection method according to the present embodiment, the pass / fail of the glass substrate 1 is determined based on the determination criterion of two, which is the number of the matching defects 3.
　また、従来の検査方法では、前記第１検査工程や前記第２検査工程と同様の検査を、ガラス基板に対して、一度行い、検出された欠陥の個数や大きさ等で、ガラス基板の合否を判定していた。また、従来の検査方法では、上記検査を複数回行ったとしても、それらの位置情報が一致した個数で判定するのではなく、それぞれの検査において、検出された欠陥の個数や大きさ等で、ガラス基板の合否を判定していた。このため、多くの場合、スクラッチやかけ等の大きな欠陥がある場合を不合格とし、例えば、１μｍ以下の小さな付着欠陥については、判断の基準にはしていなかった。 Further, in the conventional inspection method, the same inspection as the first inspection step and the second inspection step is performed once on the glass substrate, and the pass / fail of the glass substrate is determined based on the number and size of the detected defects. Was judged. Further, in the conventional inspection method, even if the above inspection is performed a plurality of times, it is not determined by the number of pieces in which the positional information is matched, but in each inspection, by the number and size of detected defects, The pass / fail of the glass substrate was determined. For this reason, in many cases, a case where there is a large defect such as scratch or scratch is rejected. For example, a small adhesion defect of 1 μm or less is not used as a criterion for judgment.
　一方、磁気記録媒体等の情報記録媒体での記録密度の向上を考慮すれば、１ビットのサイズは、数ｎｍであり、また、ヘッドの浮上量も数ｎｍであるため、１μｍ以下の小さな付着欠陥でも問題となる場合があった。 On the other hand, considering the improvement of the recording density in an information recording medium such as a magnetic recording medium, the size of 1 bit is several nm, and the flying height of the head is several nm. Even a defect sometimes caused a problem.
　また、従来の検査方法において、判断基準を高めて、１μｍ以下の小さな付着欠陥でも検出されると、不合格にした場合、空気中から付着する欠陥によって、不合格になってしまうものが増えてしまう。また、空気中から付着する欠陥は、情報記録媒体を製造する際に行う洗浄によって、容易に除去できるものであり、これらが付着されていることにより、不合格にすると、本来合格にすべきものまで、不合格にするという、いわゆるオーバーキルが発生してしまう。 In addition, in the conventional inspection method, if even a small adhesion defect of 1 μm or less is detected by increasing the judgment standard, if it is rejected, the number of defects that are rejected due to defects adhering from the air increases. End up. In addition, defects attached from the air can be easily removed by cleaning performed when manufacturing the information recording medium. So-called overkill, that is, failure, occurs.
　以上のことから、本実施形態に係る検査方法では、洗浄で除去が容易な欠陥の個数にかかわらず、洗浄で除去が困難な欠陥の個数に基づいて、ガラス基板の合否を判定することができるので、このようなオーバーキルの発生を抑制することができる。 From the above, in the inspection method according to the present embodiment, whether the glass substrate is acceptable or not can be determined based on the number of defects that are difficult to remove by cleaning, regardless of the number of defects that can be easily removed by cleaning. Therefore, the occurrence of such overkill can be suppressed.
　また、本実施形態に係る検査方法は、上記の各工程に加え、前記ガラス基板を識別するための標識を付す工程と、前記判定工程における判定結果と、前記標識とを対応づける工程とを備えることが好ましい。 Moreover, the inspection method according to the present embodiment includes, in addition to each of the above steps, a step of attaching a label for identifying the glass substrate, a step of associating the determination result in the determination step with the label. It is preferable.
　前記ガラス基板を識別するための標識を付す工程は、特に限定されない。その方法としては、ガラス基板の識別のための標識を付す方法であればよく、例えば、レーザ光をガラス基板に照射させて標識を付すレーザマーキングや、ガラス基板の上に傷をつけるけがき等が挙げられる。この中でも、チッピングのごみやかけ等の発生が少ないレーザマーキングが好ましい。 The step of attaching a label for identifying the glass substrate is not particularly limited. As the method, any method may be used as long as a label for identifying the glass substrate is attached. For example, laser marking that irradiates the glass substrate with a laser beam to attach the label, or scratches on the glass substrate. Is mentioned. Of these, laser marking is preferred because it produces less chipping dust and debris.
　また、標識を付す位置は、情報記録媒体になった際に記録面となる領域以外であることが好ましい。具体的には、ガラス基板の、内周端面、外周端面、及び内周部等の、記録面とならない非記録領域が好ましい。 Further, it is preferable that the position where the mark is attached is outside the area which becomes the recording surface when the information recording medium is obtained. Specifically, a non-recording area that does not become a recording surface, such as an inner peripheral end face, an outer peripheral end face, and an inner peripheral portion, of the glass substrate is preferable.
　また、前記標識は、ガラス基板を識別することができれば、特に限定されない。具体的には、数字、マーク、バーコード等が挙げられる。 Further, the sign is not particularly limited as long as the glass substrate can be identified. Specifically, numbers, marks, bar codes, and the like can be given.
　また、前記判定工程における判定結果と、前記標識とを対応づける工程は、前記判定工程によって得られた判定結果が、どのガラス基板の判定結果であるかが、前記標識によって判別できる工程であればよい。例えば、本実施形態に係る検査方法を実施するための検査装置等によって、その対応関係を記憶するようにしてもよい。 In addition, the step of associating the determination result in the determination step with the label is a step in which the determination result obtained in the determination step is a determination result of which glass substrate is the determination result. Good. For example, the correspondence relationship may be stored by an inspection apparatus for performing the inspection method according to the present embodiment.
　検査を行うプロセス中で使用する移送カセットの位置を、その都度記録しておく等、前記判定工程における判定結果に基づいて、前記ガラス基板を個別に分別してもよいが、上記のように、標識による管理を行うほうが、ガラス基板の表面に存在する欠陥の情報をより正確に管理することができる。すなわち、予め付された標識に、前記判定結果を対応づけたほうが、ガラス基板の表面に存在する欠陥の情報をより正確に管理することができる。 The glass substrate may be individually separated based on the determination result in the determination step, such as recording the position of the transfer cassette used in the process of performing the inspection each time. The management of the above can more accurately manage the information of the defects existing on the surface of the glass substrate. That is, the information on the defect existing on the surface of the glass substrate can be managed more accurately by associating the determination result with the label attached in advance.
　また、本実施形態に係る検査方法は、ガラス基板の検査対象である表面が、一方の面であっても、両面であってもよい。例えば、両面を検査し、前記判定工程で、一方の表面が合格で、他方の表面が不合格との判定の場合、片面合格品としての情報を、前記標識と対応づける工程を備えていてもよい。このような工程は、前記判定工程における判定結果と、前記標識とを対応づける工程と同様の方法で、片面合格品としての情報を、前記標識と対応づければよい。このような工程を備えることによって、片面合格品として管理することができる。また、前記標識と対応づけることによって、どちらの表面が合格であるかの情報も、正確に管理することができる。この片面合格品は、片面のみを記録面として利用する情報記録媒体を製造するために用いることができる。また、この片面合格品は、片面のみを記録面として利用する情報記録媒体を製造するために用いることができる。 Further, in the inspection method according to the present embodiment, the surface of the glass substrate to be inspected may be one side or both sides. For example, if both surfaces are inspected and the determination step determines that one surface is acceptable and the other surface is unacceptable, it may include a step of associating information as a single-sided acceptable product with the label. Good. Such a process should just associate the information as a single-sided pass product with the said label | marker by the method similar to the process of matching the determination result in the said determination process, and the said label | marker. By providing such a process, it can be managed as a single-sided acceptable product. In addition, by associating with the label, information on which surface is acceptable can be managed accurately. This single-sided acceptable product can be used to manufacture an information recording medium that uses only one side as a recording surface. This single-sided acceptable product can be used for manufacturing an information recording medium that uses only one side as a recording surface.
　［情報記録媒体用ガラス基板の製造方法］
　また、本実施形態に係る検査方法は、上述したように、情報記録媒体用ガラス基板の製造方法における検査工程に適用してもよい。 [Method for producing glass substrate for information recording medium]
Moreover, you may apply the inspection method which concerns on this embodiment to the inspection process in the manufacturing method of the glass substrate for information recording media, as mentioned above.
　情報記録媒体用ガラス基板の製造方法は、例えば、円盤加工工程、熱処理工程（アニール工程）、研削工程（ラッピング工程）、内外研磨工程、端面研磨工程、化学強化工程、研磨工程（ポリッシング工程）、洗浄工程（研磨後洗浄工程）、及び検査工程等を備える方法が挙げられる。そして、前記各工程を、この順番で行うものであってもよいし、これらの工程の全てを行わなくてもよいし、これら以外の工程を備える方法であってもよい。例えば、研削工程を行わない方法であってもよいし、研磨工程の後に化学強化工程を行う方法であってもよい。また、研磨工程の途中で、化学強化工程を行ってもよい。具体的には、研磨工程として、粗研磨工程、第１精密研磨工程、第２精密研磨工程を備え、第１精密研磨工程と第２精密研磨工程との間に、化学強化工程を行ってもよい。また、検査工程は、上述した検査方法を行うものであるが、全てのガラス基板に対して行ってもよいが、製造した複数のガラス基板の一部を抜き出して行ってもよい。全てのガラス基板に対して、上述した検査方法を行えば、製造された情報記録媒体用ガラス基板に、洗浄で除去が困難な欠陥が判定基準を超えるものが混入するおそれが非常に低くなる。また、製造した複数のガラス基板の一部を抜き出して行う抜き出し検査によるバッチ判定を行えば、効率的に、洗浄で除去が困難な欠陥が判定基準を超えるものの混入を抑制できる。また、バッチ処理で、不合格品が発生した場合、研磨条件や、研磨後に行う研磨後洗浄工程の洗浄条件等が同じバッチを除去することで、洗浄で除去が困難な欠陥が判定基準を超えるものの混入を効率的に抑制することができる。以下、このような抜き出し検査を行う場合について説明する。 The manufacturing method of the glass substrate for information recording media includes, for example, a disk processing step, a heat treatment step (annealing step), a grinding step (lapping step), an inner / outer polishing step, an end surface polishing step, a chemical strengthening step, a polishing step (polishing step), A method including a cleaning step (post-polishing cleaning step), an inspection step, and the like can be given. And each of the above steps may be performed in this order, all of these steps may not be performed, or a method including other steps may be used. For example, a method that does not perform the grinding step or a method that performs the chemical strengthening step after the polishing step may be used. Moreover, you may perform a chemical strengthening process in the middle of a grinding | polishing process. Specifically, the polishing process includes a rough polishing process, a first precision polishing process, and a second precision polishing process, and a chemical strengthening process is performed between the first precision polishing process and the second precision polishing process. Good. Moreover, although an inspection process performs the inspection method mentioned above, you may carry out with respect to all the glass substrates, but you may carry out by extracting a part of several manufactured glass substrate. If the above-described inspection method is performed on all the glass substrates, there is a very low possibility that defects that are difficult to remove by cleaning will exceed the criteria for determination. In addition, if batch determination is performed by extraction inspection performed by extracting a part of a plurality of manufactured glass substrates, it is possible to efficiently suppress the inclusion of defects that are difficult to remove by cleaning exceeding the determination standard. In addition, when rejected products are generated in batch processing, defects that are difficult to remove by cleaning exceed the criteria by removing batches with the same polishing conditions and cleaning conditions in the post-polishing cleaning process performed after polishing. Mixing of things can be efficiently suppressed. Hereinafter, the case where such extraction inspection is performed will be described.
　本実施形態に係る製造方法は、複数枚のガラス基板を研磨する研磨工程と、前記研磨工程の後に、前記複数枚のガラス基板の表面を洗浄する研磨後洗浄工程と、前記研磨後洗浄工程の後に、前記複数枚のガラス基板のうちの一部を抜き取り、抜き取ったガラス基板を検査する抜き取り検査工程とを備え、前記抜き取り検査工程が、上述した検査方法である情報記録媒体用ガラス基板の製造方法である。このような製造方法によれば、上述したように、洗浄で除去が困難な欠陥の少ない情報記録媒体用ガラス基板を製造することができる。具体的には、前記抜き取り検査工程で、不合格と判定された場合、そのガラス基板と同条件で、前記研磨工程や前記研磨後洗浄工程を行うことによって、得られたガラス基板を除去することで、洗浄で除去が困難な欠陥の少ない情報記録媒体用ガラス基板が得られる。 The manufacturing method according to the present embodiment includes a polishing step for polishing a plurality of glass substrates, a post-polishing cleaning step for cleaning the surfaces of the plurality of glass substrates after the polishing step, and a post-polishing cleaning step. Thereafter, a part of the plurality of glass substrates is extracted, and a sampling inspection step for inspecting the extracted glass substrate is provided, and the sampling inspection step is a manufacturing method of a glass substrate for an information recording medium according to the inspection method described above. Is the method. According to such a manufacturing method, as described above, a glass substrate for an information recording medium with few defects that is difficult to remove by cleaning can be manufactured. Specifically, when it is determined to be unacceptable in the sampling inspection process, the obtained glass substrate is removed by performing the polishing process or the post-polishing cleaning process under the same conditions as the glass substrate. Thus, a glass substrate for an information recording medium with few defects that cannot be easily removed by washing can be obtained.
　また、前記研磨工程は、情報記録媒体用ガラス基板の製造方法における研磨工程であれば、特に限定されない。また、前記研磨工程は、１回研磨であってもよいが、例えば、粗研磨工程と精密研磨工程との複数回の工程を行うものであってもよい。また、精密研磨工程も、１回であってもよいが、２回以上行ってもよい。具体的には、例えば、以下のような研磨工程が挙げられる。 Further, the polishing step is not particularly limited as long as it is a polishing step in the method for producing a glass substrate for information recording medium. Further, the polishing step may be a single polishing, but may be a step of performing a plurality of steps of a rough polishing step and a precision polishing step, for example. Further, the precision polishing step may be performed once but may be performed twice or more. Specifically, for example, the following polishing step can be mentioned.
　前記粗研磨工程（１次研磨工程）は、ガラス基板の原料であるガラス素板の表面に粗研磨を施す工程である。例えば、後述するラッピング工程が施されたガラス素板や、成形により得られたガラス素板の表面に粗研磨を施す工程である。この粗研磨は、傷や歪みの除去を目的とするもので、後述する研磨装置を用いて実施する。なお、前記粗研磨工程で研磨する表面は、ガラス素板の面方向に平行な面、すなわち主表面である。 The rough polishing step (primary polishing step) is a step of performing rough polishing on the surface of the glass base plate that is a raw material of the glass substrate. For example, it is a step of rough polishing the surface of a glass base plate that has been subjected to a lapping step, which will be described later, or a glass base plate obtained by molding. This rough polishing is intended to remove scratches and distortions, and is performed using a polishing apparatus described later. The surface to be polished in the rough polishing step is a surface parallel to the surface direction of the glass base plate, that is, the main surface.
　まず、粗研磨工程で用いる研磨装置は、ガラス基板の製造に用いる研磨装置であれば、特に限定されない。具体的には、図２に示すような研磨装置１１が挙げられる。なお、図２は、本実施形態に係る情報記録媒体用ガラス基板の製造方法における研磨工程で用いる研磨装置の一例を示す概略断面図である。 First, the polishing apparatus used in the rough polishing step is not particularly limited as long as it is a polishing apparatus used for manufacturing a glass substrate. Specifically, there is a polishing apparatus 11 as shown in FIG. FIG. 2 is a schematic cross-sectional view showing an example of a polishing apparatus used in a polishing step in the method for manufacturing a glass substrate for information recording medium according to the present embodiment.
　図２に示すような研磨装置１１は、ガラス素板の主表面の両面を、同時に研磨可能な装置である。また、この研磨装置１１は、装置本体部１１ａと、装置本体部１１ａに研磨液（研磨スラリー）を供給する研磨液供給部１１ｂとを備えている。 A polishing apparatus 11 as shown in FIG. 2 is an apparatus capable of simultaneously polishing both surfaces of the main surface of a glass base plate. The polishing apparatus 11 includes an apparatus main body 11a and a polishing liquid supply unit 11b that supplies a polishing liquid (polishing slurry) to the apparatus main body 11a.
　装置本体部１１ａは、互いに対向して配置される２枚の定盤１２，１３を備えている。それぞれの定盤の位置関係は、上下に限定されないが、例えば、２枚の定盤のうち、上側に配置される定盤を、上定盤１２とし、下側に配置される定盤を、下定盤１３と称する。すなわち、装置本体部１１ａは、円盤状の上定盤１２と円盤状の下定盤１３とを備えており、それらが互いに平行になるように上下に間隔を隔てて配置されている。そして、円盤状の上定盤１２と円盤状の下定盤１３とが、互いに逆方向に回転する。 The apparatus main body 11a includes two surface plates 12 and 13 arranged to face each other. The positional relationship between the respective surface plates is not limited to the upper and lower sides. For example, of the two surface plates, the surface plate disposed on the upper side is the upper surface plate 12, and the surface plate disposed on the lower side is This is referred to as the lower surface plate 13. That is, the apparatus main body 11a includes a disk-shaped upper surface plate 12 and a disk-shaped lower surface plate 13, and they are arranged at an interval in the vertical direction so that they are parallel to each other. Then, the disk-shaped upper surface plate 12 and the disk-shaped lower surface plate 13 rotate in directions opposite to each other.
　この円盤状の上定盤１２と円盤状の下定盤１３との対向するそれぞれの面に、ガラス素板１０の表裏の両面を研磨するための研磨パッド１５が貼り付けられている。 A polishing pad 15 for polishing both the front and back surfaces of the glass base plate 10 is attached to each surface of the disk-shaped upper surface plate 12 and the disk-shaped lower surface plate 13 facing each other.
　また、円盤状の上定盤１２と円盤状の下定盤１３との間には、回転可能な複数のキャリア１４が設けられている。このキャリア１４は、複数の素板保持用孔５１が形成されており、この素板保持用孔５１にガラス素板１０をはめ込んで配置することができる。キャリア１４としては、例えば、素板保持用孔５１が１００個形成されていて、１００枚のガラス素板１０をはめ込んで配置できるように構成されていてもよい。そうすると、１回の処理（１バッチ）で１００枚のガラス素板を処理できる。 Further, a plurality of rotatable carriers 14 are provided between the disk-shaped upper surface plate 12 and the disk-shaped lower surface plate 13. The carrier 14 is formed with a plurality of base plate holding holes 51, and the glass base plate 10 can be fitted into the base plate holding holes 51 and disposed. As the carrier 14, for example, 100 base plate holding holes 51 may be formed, and 100 glass base plates 10 may be fitted and arranged. If it does so, 100 glass base plates can be processed by one process (1 batch).
　研磨パッド１５を介して定盤１２，１３に挟まれているキャリア１４は、ガラス素板１０を保持した状態で、自転しながら、定盤１２，１３の回転中心に対して下定盤１３と同じ方向に公転する。なお、円盤状の上定盤１２と円盤状の下定盤１３とは、別駆動で動作することができる。このように動作している研磨装置１１において、研磨液１６を、上定盤１２とガラス素板１０との間、及び下定盤１３とガラス素板１０との間に、それぞれ供給することによって、ガラス素板１０の研磨を行うことができる。 The carrier 14 sandwiched between the surface plates 12 and 13 through the polishing pad 15 is the same as the lower surface plate 13 with respect to the center of rotation of the surface plates 12 and 13 while rotating while holding the glass base plate 10. Revolve in the direction. The disk-shaped upper surface plate 12 and the disk-shaped lower surface plate 13 can be operated by separate driving. In the polishing apparatus 11 operating in this way, the polishing liquid 16 is supplied between the upper surface plate 12 and the glass base plate 10 and between the lower surface plate 13 and the glass base plate 10, respectively. The glass base plate 10 can be polished.
　また、研磨液供給部１１ｂは、液貯留部１１０と液回収部１２０とを備えている。液貯留部１１０は、液貯留部本体１１０ａと、液貯留部本体１１０ａから装置本体部１１ａに延ばされた吐出口１１０ｅを有する液供給管１１０ｂとを備えている。液回収部１２０は、液回収部本体１２０ａと、液回収部本体１２０ａから装置本体部１１ａに延ばされた液回収管１２０ｂと、液回収部本体１２０ａから研磨液供給部１１ｂに延ばされた液戻し管１２０ｃとを備えている。 Moreover, the polishing liquid supply unit 11b includes a liquid storage unit 110 and a liquid recovery unit 120. The liquid reservoir 110 includes a liquid reservoir main body 110a and a liquid supply pipe 110b having a discharge port 110e extending from the liquid reservoir main body 110a to the apparatus main body 11a. The liquid recovery part 120 was extended from the liquid recovery part main body 120a, the liquid recovery pipe 120b extended from the liquid recovery part main body 120a to the apparatus main body 11a, and from the liquid recovery part main body 120a to the polishing liquid supply part 11b. And a liquid return pipe 120c.
　そして、液貯留部本体１１０ａに入れられた研磨液１６は、液供給管１１０ｂの吐出口１１０ｅから装置本体部１１ａに供給され、装置本体部１１ａから液回収管１２０ｂを介して液回収部本体１２０ａに回収される。また、回収された研磨液１６は、液戻し管１２０ｃを介して液貯留部１１０に戻され、再度、装置本体部１１ａに供給可能とされている。 Then, the polishing liquid 16 put in the liquid storage unit main body 110a is supplied from the discharge port 110e of the liquid supply pipe 110b to the apparatus main body part 11a, and from the apparatus main body part 11a through the liquid recovery pipe 120b, the liquid recovery part main body 120a. To be recovered. The recovered polishing liquid 16 is returned to the liquid storage part 110 via the liquid return pipe 120c, and can be supplied again to the apparatus main body part 11a.
　ここで用いる研磨パッドとしては、粗研磨工程に用いることができる研磨パッドであれば、特に限定されない。具体的には、硬質研磨パッド等が挙げられる。 The polishing pad used here is not particularly limited as long as it can be used in the rough polishing step. Specifically, a hard polishing pad or the like can be used.
　また、ここで用いる研磨液は、研磨剤を水に分散させた状態の液体、すなわち、スラリー液である。そして、この研磨剤としては、例えば、ＣｅＯ２を含有する研磨剤等が挙げられる。また、Ｃｅ系の研磨剤に対して安価なＺｒ系の研磨剤を用いることもできる。具体的にはＺｒＯ２やＺｒＳｉＯ４などが挙げられる。これらＺｒ系はＣｅ系の研磨材に対して研磨キズを発生しやすいため、精密研磨工程での研磨量が不足した際にサイズ１μｍ以下の微小Ｐｉｔが発生しやすいというデメリットがあるが、Ｃｅ系研磨材よりも安価である。 The polishing liquid used here is a liquid in which an abrasive is dispersed in water, that is, a slurry liquid. Then, as the polishing agent, for example, a polishing agent containing CeO 2 and the like. In addition, an inexpensive Zr-based abrasive can be used for the Ce-based abrasive. Specific examples include ZrO 2 and ZrSiO 4 . These Zr-based materials tend to generate scratches with respect to Ce-based abrasives, so there is a demerit that minute Pits with a size of 1 μm or less are likely to occur when the polishing amount in the precision polishing process is insufficient. Cheaper than abrasives.
　次に、精密研磨工程について説明する。 Next, the precision polishing process will be described.
　また、前記精密研磨工程は、前記粗研磨工程で得られた平坦平滑な主表面を維持しつつ、例えば、主表面の表面粗さ（Ｒｍａｘ）が０．３ｎｍ程度以下である平滑な鏡面に仕上げる鏡面研磨処理である。この精密研磨工程は、例えば、上記粗研磨工程で使用したものと同様の研磨装置を用い、研磨パッドを硬質研磨パッドから軟質研磨パッドに取り替えて行われる。なお、前記精密研磨工程で研磨する表面は、前記粗研磨工程で研磨する表面と同様、主表面である。なお、軟質研磨パッドとしては、例えば、スエードパッド等が挙げられる。スエードパッドとは、表面部（研磨層）が、軟質発泡ポリウレタン等の軟質発泡樹脂で構成されるスエードタイプの軟質発泡樹脂パッドである。また、スエードパッドは、気泡が表面（パッド面）に開放されており、気泡を仕切る壁が軟らかいものが相対的に多い研磨パッドである。 In addition, the precision polishing step finishes a smooth mirror surface having a surface roughness (Rmax) of about 0.3 nm or less, for example, while maintaining the flat and smooth main surface obtained in the rough polishing step. This is a mirror polishing process. This precision polishing step is performed, for example, by using a polishing apparatus similar to that used in the rough polishing step and replacing the polishing pad from a hard polishing pad to a soft polishing pad. The surface to be polished in the precision polishing step is the main surface, similar to the surface to be polished in the rough polishing step. In addition, as a soft polishing pad, a suede pad etc. are mentioned, for example. The suede pad is a suede type soft foamed resin pad whose surface (polishing layer) is made of a soft foamed resin such as soft foamed polyurethane. The suede pad is a polishing pad in which bubbles are open to the surface (pad surface), and there are relatively many soft walls separating the bubbles.
　また、精密研磨工程で用いる研磨剤としては、粗研磨工程で用いた研磨剤より、研磨性が低くても、傷の発生がより少なくなる研磨剤が用いられる。具体的には、例えば、粗研磨工程で用いた研磨剤より、粒子径が低いシリカ系の砥粒（コロイダルシリカ）を含む研磨剤等が挙げられる。このシリカ系の砥粒の平均粒子径としては、２０ｎｍ程度であることが好ましい。そして、本実施形態では、このコロイダルシリカを含む研磨剤が用いられる。 Further, as the abrasive used in the precision polishing process, an abrasive that causes less scratching even if the polishing performance is lower than that used in the rough polishing process is used. Specifically, for example, a polishing agent containing silica-based abrasive grains (colloidal silica) having a particle diameter lower than that of the polishing agent used in the rough polishing step. The average particle diameter of the silica-based abrasive is preferably about 20 nm. And in this embodiment, the abrasive | polishing agent containing this colloidal silica is used.
　そして、前記研磨剤を含む研磨液（スラリー液）をガラス素板に供給し、研磨パッドとガラス素板とを相対的に摺動させて、ガラス素板の表面を鏡面研磨する。なお、スラリー液は、例えば、上記研磨装置１１の研磨液供給部１１ｂによって循環使用してもよい。 Then, a polishing liquid (slurry liquid) containing the abrasive is supplied to the glass base plate, and the surface of the glass base plate is mirror-polished by sliding the polishing pad and the glass base plate relatively. The slurry liquid may be circulated and used by the polishing liquid supply unit 11b of the polishing apparatus 11, for example.
　スラリー液を循環使用する場合は、前記粗研磨工程と同様に、研磨によって発生するガラス屑が回収された研磨液に混入するため、図示しないフィルタを液回収部１２０に備えて前記ガラス屑を除去することが、表面に発生する傷を低減するという観点から好ましい。 When the slurry liquid is used in a circulating manner, the glass scrap generated by polishing is mixed with the recovered polishing liquid as in the rough polishing step, so a filter (not shown) is provided in the liquid recovery unit 120 to remove the glass scrap. It is preferable from the viewpoint of reducing scratches generated on the surface.
　また、前記研磨工程は、適宜、研磨条件を変えて行う。その際、前記研磨工程が、前記抜き取り検査工程での結果に基づいて、研磨条件を変更することが好ましい。具体的には、前記抜き取り検査工程で、洗浄で除去困難な欠陥を検出した場合、研磨圧力を高めたり、研磨性能の高い研磨液に変えたりして、研磨条件を厳しくする等が挙げられる。そうすることによって、前記抜き取り検査工程での判定結果に基づいて、前記研磨工程の研磨条件を変更することができるので、洗浄で除去が困難な欠陥の少ない情報記録媒体用ガラス基板を製造できる頻度を高めることができる。 Further, the polishing step is performed by appropriately changing the polishing conditions. In that case, it is preferable that the said grinding | polishing process changes grinding | polishing conditions based on the result in the said sampling inspection process. Specifically, when a defect that is difficult to remove by washing is detected in the sampling inspection process, the polishing conditions are increased by increasing the polishing pressure or changing to a polishing liquid having high polishing performance. By doing so, since the polishing conditions of the polishing step can be changed based on the determination result in the sampling inspection step, the frequency at which a glass substrate for an information recording medium with few defects that is difficult to remove by cleaning can be manufactured. Can be increased.
　また、前記研磨後洗浄工程は、前記研磨工程が施されたガラス素板を洗浄する工程である。例えば、研磨されたガラス素板の表面から研磨剤を除去するように洗浄する工程等が挙げられる。 Further, the post-polishing cleaning step is a step of cleaning the glass base plate that has been subjected to the polishing step. For example, the process etc. which wash | clean so that an abrasive | polishing agent may be removed from the surface of the grind | polished glass base plate are mentioned.
　前記洗浄工程としては、特に限定されない。具体的には、例えば、以下のような洗浄工程が挙げられる。 The cleaning process is not particularly limited. Specifically, for example, the following washing steps are mentioned.
　まず、ｐＨ１３以上のアルカリ洗剤を用いて、ガラス基板の洗浄を行い、ガラス基板にリンスを行う。次に、ｐＨ１以下の酸系洗剤を用いて、ガラス基板の洗浄を行い、ガラス基板にリンスを行う。最後に、フッ化水素酸（ＨＦ）溶液を用いて、ガラス基板の洗浄を行う。酸化セリウムに関しては、アルカリ洗浄、酸洗浄、ＨＦ洗浄の順で洗浄を行うことが最も効率的である。これは、まず、アルカリ洗剤で研磨材を分散除去し、次に酸洗剤で研磨材を溶解除去し、最後に、ＨＦによってガラス素板をエッチングし、ガラス素板に深く刺さっている研磨剤を除去するのである。 First, the glass substrate is washed with an alkaline detergent having a pH of 13 or more, and the glass substrate is rinsed. Next, the glass substrate is washed with an acid detergent having a pH of 1 or less, and the glass substrate is rinsed. Finally, the glass substrate is cleaned using a hydrofluoric acid (HF) solution. Regarding cerium oxide, it is most efficient to perform cleaning in the order of alkali cleaning, acid cleaning, and HF cleaning. First, the abrasive is dispersed and removed with an alkaline detergent, then the abrasive is dissolved and removed with an acid detergent, and finally, the glass base plate is etched with HF, and an abrasive that is deeply stuck into the glass base plate is removed. It is removed.
　前記洗浄工程は、アルカリ洗浄、酸洗浄、ＨＦ洗浄において、それぞれ別の槽で行うことが好ましい。これらの洗浄を単一の槽で行った場合には、効率的な洗浄ができない場合があるからである。特に、酸洗剤とＨＦを同一槽に入れた場合、ＨＦのエッチング速度は、研磨材の多い場所で低下するため、基板内を均一にエッチングできなくなる傾向があるからである。また、各洗浄の後にリンス槽を用いることが好ましい。これらの洗剤には、場合によって界面活性剤、分散材、キレート剤、還元材などを添加しても良い。また、各洗浄槽には、超音波を印加し、それぞれの洗剤には脱気水を使用することが好ましい。 The washing step is preferably performed in separate tanks for alkali washing, acid washing, and HF washing. This is because when these washings are performed in a single tank, efficient washing may not be possible. In particular, when the acid detergent and HF are put in the same tank, the etching rate of HF decreases at a place where there is a large amount of abrasive, and therefore there is a tendency that the inside of the substrate cannot be uniformly etched. Moreover, it is preferable to use a rinse tank after each washing. In some cases, a surfactant, a dispersing agent, a chelating agent, a reducing material, and the like may be added to these detergents. Moreover, it is preferable to apply an ultrasonic wave to each washing tank and to use deaerated water for each detergent.
　また、他の方法としては、まず、ＨＦが１質量％、硫酸が３質量％の洗浄液にガラス基板を浸漬させる。その際、その洗浄液に、８０ｋＨｚの超音波振動を印加させる。その後、ガラス基板を取り出す。そして、取り出したガラス基板を中性洗剤液に浸漬させる。その際、その中性洗剤液に、１２０ｋＨｚの超音波振動を印加させる。最後に、ガラス基板を取り出し、純水でリンスを行い、ＩＰＡ乾燥させる。 As another method, first, the glass substrate is immersed in a cleaning solution containing 1% by mass of HF and 3% by mass of sulfuric acid. At that time, an ultrasonic vibration of 80 kHz is applied to the cleaning liquid. Thereafter, the glass substrate is taken out. And the taken-out glass substrate is immersed in a neutral detergent liquid. At that time, 120 kHz ultrasonic vibration is applied to the neutral detergent solution. Finally, the glass substrate is taken out, rinsed with pure water, and dried IPA.
　また、上記のような洗浄を行った後に、スクラブ洗浄を行ってもよい。 Further, scrub cleaning may be performed after the above cleaning.
　スクラブ洗浄とは、湿式の物理洗浄方法であり、ガラス基板の表面に洗浄液を供給しながら、スクラブ部材をガラス基板に押圧した状態で、スクラブ部材とガラス基板とを相対的に移動させる方法である。そうすることで、ガラス基板の表面上の汚れをこすり取ることができる。また、このスクラブ洗浄を行う装置（スクラブ洗浄装置）としては、情報記録媒体用ガラス基板をスクラブ洗浄できる装置であれば、特に限定されない。具体的には、スクラブ部材が円筒形のロールスクラブであるロールスクラブ洗浄装置や、スクラブ部材がカップ型のカップスクラブ洗浄装置等が挙げられる。 Scrub cleaning is a wet physical cleaning method in which the scrub member and the glass substrate are relatively moved while the scrub member is pressed against the glass substrate while supplying a cleaning liquid to the surface of the glass substrate. . By doing so, dirt on the surface of the glass substrate can be scraped off. The apparatus for scrub cleaning (scrub cleaning apparatus) is not particularly limited as long as it is an apparatus capable of scrub cleaning an information recording medium glass substrate. Specifically, a roll scrub cleaning device in which the scrub member is a cylindrical roll scrub, a cup scrub cleaning device in which the scrub member is a cup type, and the like can be given.
　また、スクラブ洗浄をした後、超音波による洗浄を行うことが好ましい。 Moreover, it is preferable to perform ultrasonic cleaning after scrub cleaning.
　また、この洗浄後は、ガラス基板を乾燥させる。その乾燥方法としては、例えば、ＩＰＡ蒸気による乾燥、スピン乾燥、及び温水乾燥等が挙げられる。 Also, after this cleaning, the glass substrate is dried. Examples of the drying method include drying with IPA vapor, spin drying, and hot water drying.
　また、洗浄工程を施す前のガラス基板は、表面への異物が付着されることを防止するために、ガラス基板を液体と接触させておくことが好ましい。 In addition, it is preferable to keep the glass substrate in contact with the liquid in order to prevent foreign matter from adhering to the surface of the glass substrate before the cleaning process.
　また、前記研磨後洗浄工程は、適宜、洗浄条件を変えて行う。その際、前記研磨後洗浄工程が、前記抜き取り検査工程での結果に基づいて、洗浄条件を変更することが好ましい。具体的には、前記抜き取り検査工程で、洗浄で除去困難な欠陥を検出した場合、洗浄性の高い洗浄液に変えたり、洗浄時間を長時間化したりして、洗浄条件を厳しくする等が挙げられる。そうすることによって、前記抜き取り検査工程での判定結果に基づいて、前記研磨後洗浄工程の洗浄条件を変更することができるので、洗浄で除去が困難な欠陥の少ない情報記録媒体用ガラス基板を製造できる頻度を高めることができる。 In addition, the post-polishing cleaning step is performed by appropriately changing the cleaning conditions. At that time, it is preferable that the post-polishing cleaning process changes the cleaning conditions based on the result of the sampling inspection process. Specifically, in the sampling inspection process, when a defect that is difficult to remove by cleaning is detected, the cleaning condition is made stricter by changing to a cleaning liquid with high cleaning properties or increasing the cleaning time. . By doing so, it is possible to change the cleaning conditions in the post-polishing cleaning process based on the determination result in the sampling inspection process, and thus manufacturing a glass substrate for an information recording medium with few defects that is difficult to remove by cleaning. The frequency that can be increased.
　さらに、その後、最終洗浄を行ってもよい。すなわち、上述したように、情報記録媒体用ガラス基板が得られた後に、上記検査方法を適用してもよい。この場合、第１検査工程と第２検査工程との間に行う検査工程としては、上述したように、最終洗浄よりも簡便な洗浄であってもよい。また、検査のための洗浄である、第１検査工程と第２検査工程との間に行う検査工程として、最終洗浄を行ってもよい。また、最終洗浄は、情報記録媒体用ガラス基板の製造方法における最終洗浄と同様の洗浄であればよく、特に限定されない。例えば、超音波による洗浄等が挙げられる。 Further, a final cleaning may be performed thereafter. That is, as described above, the inspection method may be applied after the information recording medium glass substrate is obtained. In this case, the inspection process performed between the first inspection process and the second inspection process may be simpler than the final cleaning, as described above. Further, final cleaning may be performed as an inspection process performed between the first inspection process and the second inspection process, which is cleaning for inspection. The final cleaning is not particularly limited as long as it is the same cleaning as the final cleaning in the method for manufacturing the glass substrate for information recording medium. For example, cleaning with ultrasonic waves can be mentioned.
　次に、研磨工程、研磨後洗浄工程、及び検査工程以外の工程について説明する。 Next, processes other than the polishing process, the post-polishing cleaning process, and the inspection process will be described.
　前記円盤加工工程は、原料ガラスを、図３に示すような、内周及び外周が同心円となるように、中心部に貫通孔１０ａが形成された円盤状のガラス素板１０に加工する工程である。具体的には、原料ガラスを、溶融炉で溶融して、溶融ガラスとするガラス溶融工程と、溶融ガラスを円盤状のガラス素板に形成する成形工程と、形成された円盤状のガラス素板の中心部に貫通孔１０ａを形成するコアリング加工を施し、図３に示すような、円盤状のガラス素板１０に加工するコアリング加工工程等を備える。なお、図３は、本実施形態に係る情報記録媒体用ガラス基板の製造方法で用いられるガラス素板を示す上面図である。 The disk processing step is a step of processing the raw glass into a disk-shaped glass base plate 10 in which a through hole 10a is formed at the center so that the inner periphery and the outer periphery are concentric circles as shown in FIG. is there. Specifically, a glass melting step in which raw glass is melted in a melting furnace to form molten glass, a forming step in which the molten glass is formed into a disc-shaped glass base plate, and the formed disc-shaped glass base plate The coring process which forms the through-hole 10a in the center part of this, and processes to the disk shaped glass base plate 10 as shown in FIG. 3 is provided. FIG. 3 is a top view showing the glass base plate used in the method for manufacturing the glass substrate for information recording medium according to the present embodiment.
　前記ガラス溶融工程は、原料ガラスを、溶融炉で溶融して、溶融ガラスとすることができれば、特に限定されない。原料ガラスとしては、特に限定されず、例えば、ＳｉＯ２、Ｎａ２Ｏ、及びＣａＯを主成分とするソーダライムガラス、ＳｉＯ２、Ａｌ２Ｏ３、及びＲ１ ２Ｏ（式中、Ｒ１は、Ｋ、Ｎａ、又はＬｉを示す。）で表される酸化物を主成分とするアルミノシリケートガラス、ボロシリケートガラス、Ｌｉ２Ｏ－ＳｉＯ２系ガラス、Ｌｉ２Ｏ－Ａｌ２Ｏ３－ＳｉＯ２系ガラス、Ｒ２Ｏ－Ａｌ２Ｏ３－ＳｉＯ２系ガラス（式中、Ｒ２は、Ｍｇ、Ｃａ、Ｓｒ、又はＢａを示す。）等が挙げられる。より具体的には、例えば、ガラス組成が、ＳｉＯ２が５５～７５質量％、Ａｌ２Ｏ３が５～１８質量％、Ｌｉ２Ｏが１～１０質量％、Ｎａ２Ｏが３～１５質量％、Ｋ２Ｏが０．１～５質量％、ＭｇＯが０．１～５質量％、ＣａＯが０．１～５質量％であるもの等が挙げられる。これらの中でも、アルミノシリケートガラス、及びボロシリケートガラスが、耐衝撃性や耐振動性に優れる点で好ましい。また、原料ガラスの溶融方法としては、特に限定されず、通常は上記ガラス素材を公知の温度、時間にて高温で溶融する方法を採用することができる。 The glass melting step is not particularly limited as long as raw glass can be melted in a melting furnace to obtain molten glass. The starting glass is not particularly limited, for example, SiO 2, Na 2 O, and soda-lime glass composed mainly of CaO, SiO 2, Al 2 O 3, and R 1 in 2 O (wherein, R 1 is , K, Na, or Li)), aluminosilicate glass, borosilicate glass, Li 2 O—SiO 2 glass, Li 2 O—Al 2 O 3 —SiO 2 Glass, R 2 O—Al 2 O 3 —SiO 2 glass (wherein R 2 represents Mg, Ca, Sr, or Ba). More specifically, for example, the glass composition is 55 to 75% by mass of SiO 2 , 5 to 18% by mass of Al 2 O 3 , 1 to 10% by mass of Li 2 O, and 3 to 15% by mass of Na 2 O. %, K 2 O is 0.1 to 5% by mass, MgO is 0.1 to 5% by mass, and CaO is 0.1 to 5% by mass. Among these, aluminosilicate glass and borosilicate glass are preferable in that they are excellent in impact resistance and vibration resistance. Moreover, it does not specifically limit as a melting method of raw material glass, Usually, the method of fuse | melting the said glass raw material at high temperature by well-known temperature and time is employable.
　前記成形工程は、溶融ガラスを円盤状のガラス素板に形成することができれば、特に限定されない。具体的には、溶融ガラスをプレス成形により、円盤状のガラス素板を形成するプレス工程等が挙げられる。また、前記成形工程は、プレス工程に限らず、例えば、ダウンドロー法やフロート法等で形成したシートガラスを研削砥石で切り出して、円盤状のガラス素板を作製する工程であってもよい。なお、フロート法とは、例えば、ガラス素材を溶融させた溶融液を、溶融したスズの上に流し、そのまま固化させる方法である。得られたガラス素板は、一方の面がガラスの自由表面であり、他方の面が、ガラスとスズとの界面であるため、平滑性の高い、例えば、算術平均粗さＲａが０．００１μｍ以下の鏡面を備えたものとなる。また、ガラス素板の厚みとしては、例えば、０．９５ｍｍのものが挙げられる。なお、ガラス素板やガラス基板の表面粗さ、例えばＲａやＲｍａｘは、一般的な表面粗さ測定機を用いて測定することができる。 The forming step is not particularly limited as long as the molten glass can be formed into a disk-shaped glass base plate. Specifically, the press process etc. which form a disk shaped glass base plate by press molding molten glass are mentioned. The forming step is not limited to the pressing step, and may be a step of, for example, cutting a sheet glass formed by a downdraw method or a float method with a grinding stone to produce a disk-shaped glass base plate. The float method is, for example, a method in which a molten liquid obtained by melting a glass material is poured onto molten tin and solidified as it is. Since the obtained glass base plate is a free surface of glass and the other surface is an interface between glass and tin, the smoothness is high, for example, the arithmetic average roughness Ra is 0.001 μm. The following mirror surface is provided. Moreover, as a thickness of a glass base plate, a 0.95 mm thing is mentioned, for example. In addition, the surface roughness of a glass base plate or a glass substrate, for example, Ra or Rmax, can be measured using a general surface roughness measuring machine.
　また、前記コアリング加工工程は、前記成形工程で形成された円盤状のガラス素板の中心部に貫通孔１０ａを形成するコアリング加工を施す工程である。そうすることによって、図３に示すような、中心部に貫通孔１０ａが形成された円盤状のガラス素板１０が得られる。コアリング加工は、ガラス素板の中心部に貫通孔を形成する穴あけ加工であれば、特に限定されない。例えば、カッター部にダイヤモンド砥石等を備えたコアドリルや、円筒状のダイヤモンドドリル等で研削することで、ガラス素板の中心部に貫通孔を形成させる方法等が挙げられる。そうすることで、ガラス素板の中心部に貫通孔を形成され、平面視で円環状のガラス素板が得られる。 Further, the coring process is a process of performing a coring process in which a through hole 10a is formed at the center of the disk-shaped glass base plate formed in the forming process. By doing so, the disk-shaped glass base plate 10 in which the through-hole 10a was formed in the center part as shown in FIG. 3 is obtained. The coring process is not particularly limited as long as it is a drilling process that forms a through hole in the center of the glass base plate. For example, a method of forming a through-hole in the center of the glass base plate by grinding with a core drill having a diamond grindstone or the like in the cutter portion, a cylindrical diamond drill, or the like can be used. By doing so, a through hole is formed in the center of the glass base plate, and an annular glass base plate is obtained in plan view.
　前記円盤加工工程によって、例えば、外径ｒ１が２．５インチ（約６４ｍｍ）、１．８インチ（約４６ｍｍ）、１インチ（約２５ｍｍ）、０．８インチ（約２０ｍｍ）等で、厚みが２ｍｍ、１ｍｍ、０．６３ｍｍ等の円盤状のガラス素板が得られる。また、外径ｒ１が２．５インチ（約６４ｍｍ）のときは、例えば、内径ｒ２が０．８インチ（約２０ｍｍ）等に加工される。 By the disk processing step, for example, the outer diameter r1 is 2.5 inches (about 64 mm), 1.8 inches (about 46 mm), 1 inch (about 25 mm), 0.8 inches (about 20 mm), etc., and the thickness is Disc-shaped glass base plates of 2 mm, 1 mm, 0.63 mm, etc. are obtained. Further, when the outer diameter r1 is 2.5 inches (about 64 mm), for example, the inner diameter r2 is processed to 0.8 inches (about 20 mm).
　前記熱処理工程（アニール工程）は、前記ガラス素板の形状を整えるための工程である。具体的には、ガラス基板熱処理用セッタに、ガラス素板を載置した状態で、加熱炉に収納し、前記ガラス素板を熱処理する工程等が挙げられる。 The heat treatment step (annealing step) is a step for adjusting the shape of the glass base plate. Specifically, a step of heat-treating the glass base plate by storing the glass base plate in a heating furnace in a state where the glass base plate is placed on a setter for heat-treating the glass substrate is exemplified.
　前記研削工程（ラッピング工程）は、前記ガラス素板を所定の板厚に加工する工程である。具体的には、例えば、ガラス素板の両面を研削（ラッピング）加工する工程等が挙げられる。そうすることによって、ガラス素板の平行度、平坦度及び厚みを調整する。また、このラッピング工程は、１回であってもよいし、２回以上であってもよい。例えば、２回行う場合、１回目のラッピング工程（第１ラッピング工程）で、ガラス素板の平行度、平坦度及び厚みを予備調整し、２回目のラッピング工程（第２ラッピング工程）で、ガラス素板の平行度、平坦度及び厚みを微調整する。また、研削工程を２回行う場合、第１ラッピング工程と第２ラッピング工程とを連続で行ってもよいが、これらの工程の間に、後述する、内外研削工程、及び端面研磨工程を行ってもよい。 The grinding step (lapping step) is a step of processing the glass base plate to a predetermined plate thickness. Specifically, for example, a step of grinding (lapping) both surfaces of the glass base plate can be mentioned. By doing so, the parallelism, flatness and thickness of the glass base plate are adjusted. Further, this lapping step may be performed once or twice or more. For example, when it is performed twice, the parallelism, flatness and thickness of the glass base plate are preliminarily adjusted in the first lapping process (first lapping process), and glass is used in the second lapping process (second lapping process). Finely adjust the parallelism, flatness and thickness of the base plate. Moreover, when performing a grinding process twice, you may perform a 1st lapping process and a 2nd lapping process continuously, but perform the inside-and-outside grinding process mentioned later and an end surface grinding | polishing process between these processes. Also good.
　また、研削工程で用いる研削装置は、情報記録媒体用ガラス基板の製造方法における研削工程で用いる研削装置として用いることができるものであれば、特に限定されない。具体的には、前記研磨工程で用いる研磨装置と同様のものであって、研磨パッドの代わりに、固定砥粒としてダイヤモンドを使用した樹脂シート（研削シート）を用いたものが挙げられる。また、前記第１ラッピング工程としては、ガラス素板の表面全体が略均一の表面粗さとなるようにした工程等が挙げられる。 Further, the grinding apparatus used in the grinding process is not particularly limited as long as it can be used as a grinding apparatus used in the grinding process in the method of manufacturing the glass substrate for information recording medium. Specifically, it is the same as the polishing apparatus used in the polishing step, and includes a resin sheet (grinding sheet) using diamond as a fixed abrasive instead of the polishing pad. In addition, examples of the first lapping step include a step in which the entire surface of the glass base plate has a substantially uniform surface roughness.
　また、前記第２ラッピング工程としては、大きなうねり、欠け、ひび等の欠陥を除去したガラス素板が得られるようにした工程等が挙げられる。 Also, examples of the second lapping step include a step in which a glass base plate from which defects such as large undulations, chips and cracks are removed can be obtained.
　前記内外研削工程は、ガラス素板の外周端面及び内周端面を研削する工程である。具体的には、鼓状のダイヤモンド砥石等の研削砥石により、ガラス素板の外周端面および内周端面を研削する工程等が挙げられる。 The inner / outer grinding step is a step of grinding the outer peripheral end surface and the inner peripheral end surface of the glass base plate. Specifically, the process etc. which grind the outer peripheral end surface and inner peripheral end surface of a glass base plate with grinding wheels, such as a drum-shaped diamond grindstone, are mentioned.
　前記端面研磨工程は、ガラス素板の外周端面及び内周端面を研磨する工程である。具体的には、前記内外研削工程を施したガラス素板を複数枚、例えば、１００枚程度積み重ねて積層し、その状態で外周端面及び内周端面の研磨加工を、端面研磨機を用いて研磨する工程等が挙げられる。 The end surface polishing step is a step of polishing the outer peripheral end surface and the inner peripheral end surface of the glass base plate. Specifically, a plurality of glass base plates subjected to the inner and outer grinding steps, for example, about 100, are stacked and laminated, and in this state, the outer peripheral end surface and the inner peripheral end surface are polished using an end surface polishing machine. And the like.
　前記化学強化工程は、特に限定されず、具体的には、ガラス素板を化学強化液（強化処理液）に浸漬して、ガラス素板に化学強化層を形成する工程等が挙げられる。このような工程を施すことによって、ガラス素板の表面、例えば、ガラス素板表面から５μｍの領域に化学強化層を形成することができる。そして、化学強化層を形成することで耐衝撃性、耐振動性及び耐熱性等を向上させることができる。 The chemical strengthening step is not particularly limited, and specific examples include a step of immersing a glass base plate in a chemical strengthening solution (strengthening treatment solution) to form a chemical strengthening layer on the glass base plate. By performing such a process, a chemical strengthening layer can be formed in the surface of a glass base plate, for example, a 5 micrometer area | region from the glass base plate surface. And by forming a chemical strengthening layer, impact resistance, vibration resistance, heat resistance, etc. can be improved.
　より詳しくは、化学強化工程は、加熱された化学強化処理液にガラス素板を浸漬させることによって、ガラス素板に含まれるリチウムイオンやナトリウムイオン等のアルカリ金属イオンをそれよりイオン半径の大きなカリウムイオン等のアルカリ金属イオンに置換するイオン交換法によって行われる。イオン半径の違いによって生じる歪みにより、イオン交換された領域に圧縮応力が発生し、ガラス素板の表面が強化される。すなわち、この化学強化工程により、ガラス素板に強化層が好適に形成されると考えられる。 More specifically, in the chemical strengthening step, by immersing the glass base plate in a heated chemical strengthening treatment liquid, alkali metal ions such as lithium ions and sodium ions contained in the glass base plate are potassium having a larger ion radius. It is carried out by an ion exchange method for substituting alkali metal ions such as ions. Due to the strain caused by the difference in ion radius, compressive stress is generated in the ion-exchanged region, and the surface of the glass base plate is strengthened. That is, it is considered that the reinforcing layer is suitably formed on the glass base plate by this chemical strengthening step.
　化学強化処理液としては、磁気情報記録媒体用ガラス基板の製造方法における化学強化工程で用いられる化学強化処理液であれば、特に限定されない。具体的には、例えば、カリウムイオンを含む溶融液、及びカリウムイオンやナトリウムイオンを含む溶融液等が挙げられる。 The chemical strengthening treatment solution is not particularly limited as long as it is a chemical strengthening treatment solution used in the chemical strengthening step in the method for producing a glass substrate for a magnetic information recording medium. Specifically, for example, a melt containing potassium ions, a melt containing potassium ions and sodium ions, and the like can be given.
　これらの溶融液としては、例えば、硝酸カリウム、硝酸ナトリウム、炭酸カリウム、及び炭酸ナトリウム等を溶融させて得られた溶融液等が挙げられる。この中でも、硝酸カリウムを溶融させて得られた溶融液と硝酸ナトリウムを溶融させて得られた溶融液とを組み合わせて用いることが、融点が低く、ガラス素板の変形を防止する観点から好ましい。その際、硝酸カリウムを溶融させて得られた溶融液と硝酸ナトリウムを溶融させて得られた溶融液とを、ほぼ同量ずつの混合させた混合液であることが好ましい。 Examples of these melts include melts obtained by melting potassium nitrate, sodium nitrate, potassium carbonate, sodium carbonate, and the like. Among these, it is preferable to use a combination of a melt obtained by melting potassium nitrate and a melt obtained by melting sodium nitrate from the viewpoint of low melting point and preventing deformation of the glass base plate. At that time, a melt obtained by melting potassium nitrate and a melt obtained by melting sodium nitrate are preferably mixed in approximately the same amount.
　また、ガラス基板の製造方法においては、上述した研磨後洗浄工程以外の洗浄工程を、各工程の後に適宜行ってもよい。 Moreover, in the method for producing a glass substrate, a cleaning step other than the above-described post-polishing cleaning step may be appropriately performed after each step.
　次に、本実施形態に係る情報記録媒体用ガラス基板の製造方法のより具体的な態様について説明する。 Next, a more specific aspect of the method for manufacturing the glass substrate for information recording medium according to the present embodiment will be described.
　図４は、本発明の実施形態に係る情報記録媒体用ガラス基板の製造方法の一例を示す工程図である。 FIG. 4 is a process diagram showing an example of a method for producing a glass substrate for an information recording medium according to an embodiment of the present invention.
　図４に示す製造方法は、まず、研磨をする前のガラス基板（ガラス素板）を用意する。すなわち、研磨工程より前の工程を施したガラス基板を用意する。 In the manufacturing method shown in FIG. 4, first, a glass substrate (glass base plate) before polishing is prepared. That is, the glass substrate which performed the process before a grinding | polishing process is prepared.
　そして、研磨工程として、上記のような研磨を、ガラス基板に施す。その後、研磨後洗浄工程として、研磨後洗浄を行う。その際、スクラブ洗浄も行う。そして、１回目の表面検査を行う。この表面検査が、第１検査工程に相当し、図４では、表面検査１と示す。その後、この表面検査を行ったガラス基板に対して、最終洗浄を行う。その後、再度、表面検査を行う。この表面検査が、第２検査工程に相当し、図４では、表面検査２と示す。この１回目の表面検査の結果と２回目の表面検査の結果とを対比して、位置情報が変化していない欠陥の個数に基づいて、ガラス基板の合否を判定する。そして、合格したガラス基板を出荷する。 Then, as a polishing step, the glass substrate is polished as described above. Thereafter, post-polishing cleaning is performed as a post-polishing cleaning step. At that time, scrub cleaning is also performed. Then, the first surface inspection is performed. This surface inspection corresponds to the first inspection step and is shown as surface inspection 1 in FIG. Thereafter, final cleaning is performed on the glass substrate subjected to the surface inspection. Thereafter, the surface inspection is performed again. This surface inspection corresponds to the second inspection step and is shown as surface inspection 2 in FIG. The result of the first surface inspection is compared with the result of the second surface inspection, and the pass / fail of the glass substrate is determined based on the number of defects whose positional information has not changed. And the glass substrate which passed is shipped.
　このような情報記録媒体用ガラス基板の製造方法であれば、上述したように、洗浄で除去が困難な欠陥の少ない情報記録媒体用ガラス基板を製造することができる。 Such a method for producing a glass substrate for an information recording medium can produce a glass substrate for an information recording medium with few defects that is difficult to remove by washing, as described above.
　次に、図５は、本発明の実施形態に係る情報記録媒体用ガラス基板の製造方法の他の一例を示す工程図である。 Next, FIG. 5 is a process diagram showing another example of the method for manufacturing the glass substrate for information recording medium according to the embodiment of the present invention.
　図５に示す製造方法は、図４と同様、まず、研磨をする前のガラス基板（ガラス素板）を用意する。そして、研磨工程として、上記のような研磨を、ガラス基板に施す。その後、研磨後洗浄工程として、研磨後洗浄を行う。その際、スクラブ洗浄も行う。その後、最終洗浄を行う。このように、最終洗浄まで行ったガラス基板、すなわち、情報記録媒体用ガラス基板としての完成品に対して、検査を行う。具体的には、最終洗浄まで行ったガラス基板に対して、１回目の表面検査を行う。この表面検査が、第１検査工程に相当し、図５では、表面検査１と示す。その後、この表面検査を行ったガラス基板に対して、最終洗浄より簡易な検査のための検査洗浄を行う。その後、再度、表面検査を行う。この表面検査が、第２検査工程に相当し、図５では、表面検査２と示す。この１回目の表面検査の結果と２回目の表面検査の結果とを対比して、位置情報が変化していない欠陥の個数に基づいて、ガラス基板の合否を判定する。そして、合格したガラス基板を出荷する。 In the manufacturing method shown in FIG. 5, as in FIG. 4, first, a glass substrate (glass base plate) before polishing is prepared. And as a grinding | polishing process, the above grinding | polishing is given to a glass substrate. Thereafter, post-polishing cleaning is performed as a post-polishing cleaning step. At that time, scrub cleaning is also performed. Thereafter, final cleaning is performed. In this manner, the glass substrate that has been subjected to the final cleaning, that is, the finished product as the information recording medium glass substrate is inspected. Specifically, the first surface inspection is performed on the glass substrate that has been subjected to the final cleaning. This surface inspection corresponds to the first inspection step and is shown as surface inspection 1 in FIG. Thereafter, the glass substrate subjected to the surface inspection is subjected to inspection cleaning for simpler inspection than the final cleaning. Thereafter, the surface inspection is performed again. This surface inspection corresponds to the second inspection step and is shown as surface inspection 2 in FIG. The result of the first surface inspection is compared with the result of the second surface inspection, and the pass / fail of the glass substrate is determined based on the number of defects whose positional information has not changed. And the glass substrate which passed is shipped.
　このような情報記録媒体用ガラス基板の製造方法であれば、上述したように、洗浄で除去が困難な欠陥の少ない情報記録媒体用ガラス基板を製造することができる。このように最終洗浄まで行ったガラス基板に対して、検査を行い、その検査結果に基づいて、出荷するか否かを決定することができる。 Such a method for producing a glass substrate for an information recording medium can produce a glass substrate for an information recording medium with few defects that is difficult to remove by washing, as described above. Thus, it can test | inspect with respect to the glass substrate performed to the last washing | cleaning, and can determine whether it ships based on the test result.
　上記のような本実施形態と比較するための実施形態について説明する。 An embodiment for comparison with the present embodiment as described above will be described.
　図６は、本発明の実施形態と比較するための情報記録媒体用ガラス基板の製造方法の一例を示す工程図である。 FIG. 6 is a process diagram showing an example of a method for producing a glass substrate for an information recording medium for comparison with an embodiment of the present invention.
　この製造方法は、本実施形態に係る検査方法を適用しない、従来の製造方法である。図６に示す製造方法は、図４と同様、まず、研磨をする前のガラス基板（ガラス素板）を用意する。そして、研磨工程として、上記のような研磨を、ガラス基板に施す。その後、研磨後洗浄工程として、研磨後洗浄を行う。その際、スクラブ洗浄も行う。その後、最終洗浄を行う。このように、最終洗浄まで行ったガラス基板、すなわち、情報記録媒体用ガラス基板としての完成品に対して、検査を行ってもよい。具体的には、最終洗浄まで行ったガラス基板に対して、表面検査を行う。その表面検査により得られた、欠陥の数や大きさに基づいて、ガラス基板の合否を判定する。そして、合格したガラス基板を出荷する。 This manufacturing method is a conventional manufacturing method that does not apply the inspection method according to the present embodiment. In the manufacturing method shown in FIG. 6, as in FIG. 4, first, a glass substrate (glass base plate) before polishing is prepared. And as a grinding | polishing process, the above grinding | polishing is given to a glass substrate. Thereafter, post-polishing cleaning is performed as a post-polishing cleaning step. At that time, scrub cleaning is also performed. Thereafter, final cleaning is performed. In this manner, the glass substrate that has been subjected to the final cleaning, that is, the finished product as the information recording medium glass substrate may be inspected. Specifically, surface inspection is performed on a glass substrate that has been subjected to final cleaning. The pass / fail of the glass substrate is determined based on the number and size of defects obtained by the surface inspection. And the glass substrate which passed is shipped.
　このような情報記録媒体用ガラス基板の製造方法であれば、本実施形態に係る製造方法とは異なり、洗浄で除去が容易な欠陥も基準に含めて、ガラス基板の合否を判定している。このことにより、判定基準を緩くすると、得られたガラス基板の欠陥が多くなってしまう。一方、判定基準を厳しくすると、不合格となったものでも、洗浄で除去が困難な欠陥の少ないものも含まれる状態になってしまうことがある。 In such a method for manufacturing a glass substrate for an information recording medium, unlike the manufacturing method according to the present embodiment, the pass / fail of the glass substrate is determined including defects that can be easily removed by cleaning. For this reason, if the judgment criteria are loosened, defects in the obtained glass substrate increase. On the other hand, if the judgment criteria are strict, even those that are rejected may be in a state where there are few defects that are difficult to remove by cleaning.
　以上のことから、本実施形態によれば、洗浄で除去が困難な欠陥を精度良く検出できる。 From the above, according to this embodiment, it is possible to accurately detect defects that are difficult to remove by cleaning.
　次に、本実施形態に係る情報記録媒体用ガラス基板の製造方法により製造された情報記録媒体用ガラス基板を用いた磁気記録媒体について説明する。 Next, a magnetic recording medium using the glass substrate for information recording medium manufactured by the method for manufacturing the glass substrate for information recording medium according to the present embodiment will be described.
　図７は、本実施形態に係る情報記録媒体用ガラス基板の製造方法により製造された情報記録媒体用ガラス基板を用いた磁気記録媒体の一例である磁気ディスクを示す一部断面斜視図である。この磁気ディスクＤは、円形の情報記録媒体用ガラス基板１０１の主表面に形成された磁性膜１０２を備えている。磁性膜１０２の形成には、公知の常套手段による形成方法が用いられる。例えば、磁性粒子を分散させた熱硬化性樹脂を情報記録媒体用ガラス基板１０１上にスピンコートすることによって磁性膜１０２を形成する形成方法（スピンコート法）や、情報記録媒体用ガラス基板１０１上にスパッタリングによって磁性膜１０２を形成する形成方法（スパッタリング法）や、情報記録媒体用ガラス基板１０１上に無電解めっきによって磁性膜１０２を形成する形成方法（無電解めっき法）等が挙げられる。磁性膜１０２の膜厚は、スピンコート法による場合では、約０．３～１．２μｍ程度であり、スパッタリング法による場合では、約０．０４～０．０８μｍ程度であり、無電解めっき法による場合では、約０．０５～０．１μｍ程度である。薄膜化および高密度化の観点から、スパッタリング法による膜形成が好ましく、また、無電解めっき法による膜形成が好ましい。 FIG. 7 is a partial cross-sectional perspective view showing a magnetic disk as an example of a magnetic recording medium using the glass substrate for information recording medium manufactured by the method for manufacturing the glass substrate for information recording medium according to the present embodiment. This magnetic disk D includes a magnetic film 102 formed on the main surface of a circular glass substrate 101 for an information recording medium. For the formation of the magnetic film 102, a known method is used. For example, a formation method (spin coating method) for forming the magnetic film 102 by spin-coating a thermosetting resin in which magnetic particles are dispersed on the glass substrate 101 for information recording medium, Examples thereof include a forming method for forming the magnetic film 102 by sputtering (sputtering method) and a forming method for forming the magnetic film 102 on the glass substrate 101 for information recording medium by electroless plating (electroless plating method). The thickness of the magnetic film 102 is about 0.3 to 1.2 μm in the case of the spin coating method, and about 0.04 to 0.08 μm in the case of the sputtering method, and is based on the electroless plating method. In some cases, the thickness is about 0.05 to 0.1 μm. From the viewpoint of thinning and densification, film formation by sputtering is preferable, and film formation by electroless plating is preferable.
　磁性膜１０２に用いる磁性材料は、公知の任意の材料を用いることができ、特に限定されない。磁性材料は、例えば、高い保持力を得るために結晶異方性の高いＣｏを基本とし、残留磁束密度を調整する目的でＮｉやＣｒを加えたＣｏ系合金等が好ましい。より具体的には、Ｃｏを主成分とするＣｏＰｔ、ＣｏＣｒ、ＣｏＮｉ、ＣｏＮｉＣｒ、ＣｏＣｒＴａ、ＣｏＰｔＣｒ、ＣｏＮｉＰｔ、ＣｏＮｉＣｒＰｔ、ＣｏＮｉＣｒＴａ、ＣｏＣｒＰｔＴａ、ＣｏＣｒＰｔＢ、ＣｏＣｒＰｔＳｉＯ等が挙げられる。磁性膜１０２は、ノイズの低減を図るために、非磁性膜（例えば、Ｃｒ、ＣｒＭｏ、ＣｒＶ等）で分割された多層構成（例えば、ＣｏＰｔＣｒ／ＣｒＭｏ／ＣｏＰｔＣｒ、ＣｏＣｒＰｔＴａ／ＣｒＭｏ／ＣｏＣｒＰｔＴａ等）であってもよい。磁性膜１０２に用いる磁性材料は、上記磁性材料の他、フェライト系や鉄－希土類系であってもよく、また、ＳｉＯ２、ＢＮ等からなる非磁性膜中にＦｅ、Ｃｏ、ＦｅＣｏ、ＣｏＮｉＰｔ等の磁性粒子を分散した構造のグラニュラー等であってもよい。また、磁性膜１０２への記録には、内面型および垂直型のいずれかの記録形式が用いられてよい。 The magnetic material used for the magnetic film 102 can be any known material and is not particularly limited. The magnetic material is preferably, for example, a Co-based alloy based on Co having high crystal anisotropy in order to obtain a high coercive force, and Ni or Cr added for the purpose of adjusting the residual magnetic flux density. More specifically, CoPt, CoCr, CoNi, CoNiCr, CoCrTa, CoPtCr, CoNiPt, CoNiCrPt, CoNiCrTa, CoCrPtTa, CoCrPtB, CoCrPtSiO, and the like whose main component is Co can be given. The magnetic film 102 has a multilayer structure (for example, CoPtCr / CrMo / CoPtCr, CoCrPtTa / CrMo / CoCrPtTa, etc.) divided by a nonmagnetic film (for example, Cr, CrMo, CrV, etc.) in order to reduce noise. May be. Magnetic material used for the magnetic layer 102, in addition to the magnetic material, ferrite or iron - may be a rare earth, also, Fe in a non-magnetic film made of SiO 2, BN, etc., Co, FeCo, CoNiPt and the like A granular material having a structure in which the magnetic particles are dispersed may be used. In addition, for recording on the magnetic film 102, either an inner surface type or a vertical type recording format may be used.
　また、磁気ヘッドの滑りをよくするために、磁性膜１０２の表面には、潤滑剤が薄くコーティングされてもよい。潤滑剤として、例えば液体潤滑剤であるパーフロロポリエーテル（ＰＦＰＥ）をフレオン系などの溶媒で希釈したものが挙げられる。 Further, in order to improve the sliding of the magnetic head, the surface of the magnetic film 102 may be thinly coated with a lubricant. Examples of the lubricant include those obtained by diluting perfluoropolyether (PFPE), which is a liquid lubricant, with a freon-based solvent.
　さらに必要により磁性膜１０２に対し下地層や保護層が設けられてもよい。磁気ディスクＤにおける下地層は、磁性膜１０２に応じて適宜に選択される。下地層の材料として、例えば、Ｃｒ、Ｍｏ、Ｔａ、Ｔｉ、Ｗ、Ｖ、Ｂ、Ａｌ、Ｎｉ等の非磁性金属から選ばれる少なくとも一種以上の材料が挙げられる。例えば、Ｃｏを主成分とする磁性膜１０２の場合には、下地層の材料は、磁気特性向上等の観点からＣｒ単体やＣｒ合金であることが好ましい。また、下地層は、単層とは限らず、同一または異種の層を積層した複数層構造であってもよい。このような複数層構造の下地層は、例えば、Ｃｒ／Ｃｒ、Ｃｒ／ＣｒＭｏ、Ｃｒ／ＣｒＶ、ＮｉＡｌ／Ｃｒ、ＮｉＡｌ／ＣｒＭｏ、ＮｉＡｌ／ＣｒＶ等の多層下地層が挙げられる。磁性膜１０２の摩耗や腐食を防止する保護層として、例えば、Ｃｒ層、Ｃｒ合金層、カーボン層、水素化カーボン層、ジルコニア層、シリカ層等が挙げられる。これら保護層は、下地層および磁性膜１０２と共にインライン型スパッタ装置で連続して形成することができる。また、これら保護層は、単層としてもよく、あるいは、同一または異種の層からなる複数層構成であってもよい。なお、上記保護層上に、あるいは、上記保護層に代えて、他の保護層が形成されてもよい。例えば、上記保護層に代えて、Ｃｒ層の上にＳｉＯ２層が形成されてもよい。このようなＳｉＯ２層は、Ｃｒ層の上にテトラアルコキシシランをアルコール系の溶媒で希釈した中に、コロイダルシリカ微粒子を分散して塗布し、さらに焼成することによって形成される。 Furthermore, an underlayer or a protective layer may be provided on the magnetic film 102 as necessary. The underlayer in the magnetic disk D is appropriately selected according to the magnetic film 102. Examples of the material for the underlayer include at least one material selected from nonmagnetic metals such as Cr, Mo, Ta, Ti, W, V, B, Al, and Ni. For example, in the case of the magnetic film 102 containing Co as a main component, the material of the underlayer is preferably Cr alone or a Cr alloy from the viewpoint of improving magnetic characteristics. Further, the underlayer is not limited to a single layer, and may have a multilayer structure in which the same or different layers are stacked. Examples of such an underlayer having a multilayer structure include multilayer underlayers such as Cr / Cr, Cr / CrMo, Cr / CrV, NiAl / Cr, NiAl / CrMo, and NiAl / CrV. Examples of the protective layer that prevents wear and corrosion of the magnetic film 102 include a Cr layer, a Cr alloy layer, a carbon layer, a hydrogenated carbon layer, a zirconia layer, and a silica layer. These protective layers can be continuously formed with the underlayer and the magnetic film 102 by an in-line sputtering apparatus. These protective layers may be a single layer, or may be a multi-layer structure composed of the same or different layers. Note that another protective layer may be formed on the protective layer or instead of the protective layer. For example, instead of the protective layer, a SiO 2 layer may be formed on the Cr layer. Such a SiO 2 layer is formed by dispersing and applying colloidal silica fine particles in a tetraalkoxysilane diluted with an alcohol-based solvent on the Cr layer and further baking.
　このような本実施形態における情報記録媒体用ガラス基板１０１を基体とした磁気記録媒体は、情報記録媒体用ガラス基板１０１が上述した組成により形成されるので、情報の記録再生を長期に亘り高い信頼性で行うことができる。 In such a magnetic recording medium based on the information recording medium glass substrate 101 according to the present embodiment, the information recording medium glass substrate 101 is formed with the above-described composition. Can be done by sex.
　なお、上述では、本実施形態における情報記録媒体用ガラス基板１０１を磁気記録媒体（磁気ディスク）に用いた場合について説明したが、これに限定されるものではなく、本実施形態における情報記録媒体用ガラス基板１０１は、光磁気ディスクや光ディスク等にも用いることが可能である。 In addition, although the case where the glass substrate 101 for information recording media in this embodiment was used for a magnetic recording medium (magnetic disk) was demonstrated above, it is not limited to this, For information recording media in this embodiment The glass substrate 101 can also be used for magneto-optical disks, optical disks, and the like.
　本明細書は、上述したように、様々な態様の技術を開示しているが、そのうち主な技術を纏める。 This specification discloses various aspects of the technology as described above, but the main technologies are summarized.
　本発明の一局面は、前記ガラス基板の表面に存在する欠陥を検出し、前記欠陥の位置情報を取得する第１検査工程と、前記第１検査工程の後に、前記ガラス基板の表面を洗浄する洗浄工程と、前記洗浄工程の後に、前記ガラス基板の表面に存在する欠陥を検出し、前記欠陥の位置情報を取得する第２検査工程と、前記第１検査工程で取得した欠陥の位置情報と、前記第２検査工程で取得した欠陥の位置情報とが一致している個数に基づいて、前記ガラス基板の合否を判定する判定工程とを備える情報記録媒体用ガラス基板の検査方法である。 One aspect of the present invention is to detect a defect present on the surface of the glass substrate and obtain positional information of the defect, and after the first inspection step, clean the surface of the glass substrate. A cleaning step, a second inspection step for detecting defects present on the surface of the glass substrate after the cleaning step, and acquiring positional information of the defects; and positional information of the defects acquired in the first inspection step; And a glass substrate inspection method for an information recording medium, comprising: a determination step of determining pass / fail of the glass substrate on the basis of the number of coincident positions of defect positions acquired in the second inspection step.
　このような構成によれば、前記第２検査工程で取得した欠陥の位置情報と、前記洗浄工程での洗浄の前に予め取得しておいた、前記第１検査工程における位置情報とが一致している個数に基づいて、ガラス基板の合否を判定する。このことは、判定に用いた個数が、洗浄工程で移動しなかった欠陥の個数であることを意味すると考えられる。そして、洗浄工程で移動しなかった欠陥は、洗浄で除去が困難な欠陥の個数であると考えられる。また、前記第２検査工程で検出された欠陥で、前記第１検査工程で取得した欠陥の位置情報と前記第２検査工程で取得した欠陥の位置情報とが一致しなかった欠陥は、前記洗浄工程において、再付着した異物欠陥等の欠陥であり、再度、洗浄することによって、除去可能な欠陥であると考えられる。これらのことから、上記のような基準で、ガラス基板の合否を判定することによって、洗浄で除去が容易な欠陥の個数にかかわらず、洗浄で除去が困難な欠陥の個数に基づいて、ガラス基板の合否を判定することができる。 According to such a configuration, the position information of the defect acquired in the second inspection process matches the position information in the first inspection process acquired in advance before cleaning in the cleaning process. The acceptance / rejection of the glass substrate is determined based on the number. This is considered to mean that the number used for the determination is the number of defects that did not move in the cleaning process. The defects that have not moved in the cleaning process are considered to be the number of defects that are difficult to remove by cleaning. In addition, the defect detected in the second inspection step and the defect position information acquired in the first inspection step and the defect position information acquired in the second inspection step do not coincide with each other. In the process, it is a defect such as a foreign matter defect that has been reattached and is considered to be a defect that can be removed by washing again. Based on the above, based on the number of defects that are difficult to remove by cleaning, regardless of the number of defects that can be easily removed by cleaning, the glass substrate is determined by determining whether the glass substrate is acceptable or not based on the above criteria. Pass / fail can be determined.
　以上のことから、上記の構成によれば、洗浄で除去が困難な欠陥を精度良く検出できる情報記録媒体用ガラス基板の検査方法を提供することができる。 From the above, according to the above configuration, it is possible to provide a method for inspecting a glass substrate for an information recording medium capable of accurately detecting defects that are difficult to remove by cleaning.
　また、前記情報記録媒体用ガラス基板の検査方法において、前記第１検査工程及び前記第２検査工程が、前記ガラス基板に検査光を照射し、前記検査光の反射光及び散乱光に基づいて、欠陥の検出を行うことが好ましい。 In the inspection method of the glass substrate for information recording medium, the first inspection step and the second inspection step irradiate the glass substrate with inspection light, and based on reflected light and scattered light of the inspection light, It is preferable to detect defects.
　このような構成によれば、簡便な方法で、欠陥の検出ができる。よって、洗浄で除去が困難な欠陥を精度良く、且つ、簡便に行うことができる。 According to such a configuration, the defect can be detected by a simple method. Therefore, it is possible to accurately and easily perform defects that are difficult to remove by cleaning.
　また、前記情報記録媒体用ガラス基板の検査方法において、前記ガラス基板を識別するための標識を付す工程と、前記判定工程における判定結果と、前記標識とを対応づける工程とを備えることが好ましい。 Further, in the method for inspecting the glass substrate for information recording medium, it is preferable to include a step of attaching a label for identifying the glass substrate, a step of associating the determination result in the determination step with the label.
　このような構成によれば、前記判定工程における判定結果に基づいて、前記ガラス基板を個別に分別するよりも、予め付された標識に、前記判定結果を対応づけたほうが、ガラス基板の表面に存在する欠陥の情報をより正確に管理することができる。 According to such a configuration, it is better to associate the determination result with the label attached in advance to the surface of the glass substrate than to separate the glass substrates individually based on the determination result in the determination step. Information about existing defects can be managed more accurately.
　また、前記情報記録媒体用ガラス基板の検査方法において、前記表面が、両面であり、前記判定工程で、一方の表面が合格で、他方の表面が不合格との判定の場合、片面合格品としての情報を、前記標識と対応づける工程を備えることが好ましい。 Moreover, in the said inspection method of the glass substrate for information recording media, when the said surface is both surfaces, and the determination process WHEREIN: One surface is a pass and the other surface is a determination of disqualified, It is preferable that the method includes a step of associating the information with the label.
　このような構成によれば、前記ガラス基板の両面に、前記検査方法を行い、一方の表面が合格で、他方の表面が不合格との判定の場合、片面合格品としての情報を、前記標識と対応づけることによって、片面合格品として管理することができる。また、前記標識と対応づけることによって、どちらの表面が合格であるかの情報も、正確に管理することができる。この片面合格品は、片面のみを記録面として利用する情報記録媒体を製造するために用いることができる。 According to such a configuration, when the inspection method is performed on both surfaces of the glass substrate and one surface is acceptable and the other surface is unacceptable, information as a single-sided acceptable product is displayed on the label. Can be managed as a single-sided acceptable product. In addition, by associating with the label, information on which surface is acceptable can be managed accurately. This single-sided acceptable product can be used to manufacture an information recording medium that uses only one side as a recording surface.
　また、本発明の他の一局面は、複数枚のガラス基板を研磨する研磨工程と、前記研磨工程の後に、前記複数枚のガラス基板の表面を洗浄する研磨後洗浄工程と、前記研磨後洗浄工程の後に、前記複数枚のガラス基板のうちの一部を抜き取り、抜き取ったガラス基板を検査する抜き取り検査工程とを備え、前記抜き取り検査工程が、前記検査方法である情報記録媒体用ガラス基板の製造方法である。 Another aspect of the present invention is a polishing step for polishing a plurality of glass substrates, a post-polishing cleaning step for cleaning the surfaces of the plurality of glass substrates after the polishing step, and the post-polishing cleaning. A step of extracting a part of the plurality of glass substrates after the step, and a sampling inspection step of inspecting the extracted glass substrate, wherein the sampling inspection step of the glass substrate for information recording medium is the inspection method; It is a manufacturing method.
　このような構成によれば、洗浄で除去が困難な欠陥の少ない情報記録媒体用ガラス基板を製造することができる。具体的には、前記抜き取り検査工程で、不合格と判定された場合、そのガラス基板と同条件で、前記研磨工程や前記研磨後洗浄工程を行うことによって、得られたガラス基板を除去することで、洗浄で除去が困難な欠陥の少ない情報記録媒体用ガラス基板が得られる。 According to such a configuration, a glass substrate for an information recording medium with few defects that is difficult to remove by cleaning can be manufactured. Specifically, when it is determined to be unacceptable in the sampling inspection process, the obtained glass substrate is removed by performing the polishing process or the post-polishing cleaning process under the same conditions as the glass substrate. Thus, a glass substrate for an information recording medium with few defects that cannot be easily removed by washing can be obtained.
　また、前記情報記録媒体用ガラス基板の製造方法において、前記研磨工程が、前記抜き取り検査工程での結果に基づいて、研磨条件を変更することが好ましい。 Further, in the method for manufacturing the glass substrate for information recording medium, it is preferable that the polishing step changes polishing conditions based on a result in the sampling inspection step.
　このような構成によれば、前記抜き取り検査工程での判定結果に基づいて、前記研磨工程の研磨条件を変更することができるので、洗浄で除去が困難な欠陥の少ない情報記録媒体用ガラス基板を製造できる頻度を高めることができる。 According to such a configuration, since the polishing conditions of the polishing step can be changed based on the determination result in the sampling inspection step, a glass substrate for an information recording medium with few defects that is difficult to remove by cleaning is obtained. The frequency which can be manufactured can be raised.
　また、前記情報記録媒体用ガラス基板の製造方法において、前記研磨後洗浄工程が、前記抜き取り検査工程での結果に基づいて、洗浄条件を変更することが好ましい。 Moreover, in the method for manufacturing the glass substrate for information recording medium, it is preferable that the post-polishing cleaning step changes the cleaning conditions based on the result of the sampling inspection step.
　このような構成によれば、前記抜き取り検査工程での判定結果に基づいて、前記研磨後洗浄工程の洗浄条件を変更することができるので、洗浄で除去が困難な欠陥の少ない情報記録媒体用ガラス基板を製造できる頻度を高めることができる。 According to such a configuration, since the cleaning conditions of the post-polishing cleaning step can be changed based on the determination result in the sampling inspection step, the glass for information recording media with few defects that is difficult to remove by cleaning. The frequency with which the substrate can be manufactured can be increased.
　本発明によれば、洗浄で除去が困難な欠陥を精度良く検出できる情報記録媒体用ガラス基板の検査方法が提供される。また、本発明によれば、この検査方法を用いた情報記録媒体用ガラス基板の製造方法が提供される。 According to the present invention, a method for inspecting a glass substrate for an information recording medium capable of accurately detecting defects that are difficult to remove by cleaning is provided. Moreover, according to this invention, the manufacturing method of the glass substrate for information recording media using this test | inspection method is provided.

Claims (7)

  1. 　情報記録媒体用ガラス基板の検査方法であって、
    　前記ガラス基板の表面に存在する欠陥を検出し、前記欠陥の位置情報を取得する第１検査工程と、
    　前記第１検査工程の後に、前記ガラス基板の表面を洗浄する洗浄工程と、
    　前記洗浄工程の後に、前記ガラス基板の表面に存在する欠陥を検出し、前記欠陥の位置情報を取得する第２検査工程と、
    　前記第１検査工程で取得した欠陥の位置情報と、前記第２検査工程で取得した欠陥の位置情報とが一致している個数に基づいて、前記ガラス基板の合否を判定する判定工程とを備える情報記録媒体用ガラス基板の検査方法。     A method for inspecting a glass substrate for an information recording medium,
    Detecting a defect present on the surface of the glass substrate and obtaining positional information of the defect; and
    A cleaning step of cleaning the surface of the glass substrate after the first inspection step;
    A second inspection step of detecting defects present on the surface of the glass substrate after the cleaning step, and acquiring positional information of the defects;
    A determination step of determining pass / fail of the glass substrate on the basis of the number of the position information of the defect acquired in the first inspection step and the position information of the defect acquired in the second inspection step. Inspection method of glass substrate for information recording medium.
  2. 　前記第１検査工程及び前記第２検査工程が、前記ガラス基板に検査光を照射し、前記検査光の反射光及び散乱光に基づいて、欠陥の検出を行う請求項１に記載の情報記録媒体用ガラス基板の検査方法。 The information recording medium according to claim 1, wherein the first inspection step and the second inspection step irradiate the glass substrate with inspection light, and detect a defect based on reflected light and scattered light of the inspection light. Glass substrate inspection method.
  3. 　前記ガラス基板を識別するための標識を付す工程と、
    　前記判定工程における判定結果と、前記標識とを対応づける工程とを備える請求項１又は請求項２に記載の情報記録媒体用ガラス基板の検査方法。     Attaching a label for identifying the glass substrate;
    The inspection method of the glass substrate for information recording media of Claim 1 or Claim 2 provided with the process of matching the determination result in the said determination process, and the said label | marker.
  4. 　前記表面が、両面であり、
    　前記判定工程で、一方の表面が合格で、他方の表面が不合格との判定の場合、片面合格品としての情報を、前記標識と対応づける工程を備える請求項３に記載の情報記録媒体用ガラス基板の検査方法。     The surface is double-sided,
    The information recording medium according to claim 3, further comprising a step of associating information as a single-sided acceptable product with the mark when it is determined that one surface is acceptable and the other surface is unacceptable in the determination step. Inspection method for glass substrates.
  5. 　複数枚のガラス基板を研磨する研磨工程と、
    　前記研磨工程の後に、前記複数枚のガラス基板の表面を洗浄する研磨後洗浄工程と、
    　前記研磨後洗浄工程の後に、前記複数枚のガラス基板のうちの一部を抜き取り、抜き取ったガラス基板を検査する抜き取り検査工程とを備え、
    　前記抜き取り検査工程が、請求項１～４のいずれか１項に記載の検査方法である情報記録媒体用ガラス基板の製造方法。     A polishing step of polishing a plurality of glass substrates;
    After the polishing step, a post-polishing cleaning step for cleaning the surfaces of the plurality of glass substrates;
    After the post-polishing cleaning step, a part of the plurality of glass substrates is extracted, and a sampling inspection step for inspecting the extracted glass substrate,
    The method for manufacturing a glass substrate for an information recording medium, wherein the sampling inspection step is the inspection method according to any one of claims 1 to 4.
  6. 　前記研磨工程が、前記抜き取り検査工程での判定結果に基づいて、研磨条件を変更する請求項５に記載の情報記録媒体用ガラス基板の製造方法。 The method for manufacturing a glass substrate for an information recording medium according to claim 5, wherein the polishing step changes polishing conditions based on a determination result in the sampling inspection step.
  7. 　前記研磨後洗浄工程が、前記抜き取り検査工程での判定結果に基づいて、洗浄条件を変更する請求項５に記載の情報記録媒体用ガラス基板の製造方法。 The method for manufacturing a glass substrate for an information recording medium according to claim 5, wherein the post-polishing cleaning step changes cleaning conditions based on a determination result in the sampling inspection step.
PCT/JP2013/004957 2012-09-27 2013-08-22 Method for inspecting glass substrate for information storage medium, and method for manufacturing glass substrate for information storage medium WO2014049947A1 (en)

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