WO2012043314A1 - Procédé de production d'un substrat en verre à utiliser dans un support d'enregistrement d'informations et support d'enregistrement d'informations - Google Patents

Procédé de production d'un substrat en verre à utiliser dans un support d'enregistrement d'informations et support d'enregistrement d'informations Download PDF

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Publication number
WO2012043314A1
WO2012043314A1 PCT/JP2011/071421 JP2011071421W WO2012043314A1 WO 2012043314 A1 WO2012043314 A1 WO 2012043314A1 JP 2011071421 W JP2011071421 W JP 2011071421W WO 2012043314 A1 WO2012043314 A1 WO 2012043314A1
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WIPO (PCT)
Prior art keywords
glass substrate
main surface
information recording
cleaning process
recording medium
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PCT/JP2011/071421
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English (en)
Japanese (ja)
Inventor
直之 福本
登史晴 森
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コニカミノルタオプト株式会社
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Publication of WO2012043314A1 publication Critical patent/WO2012043314A1/fr

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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 manufacturing a glass substrate for information recording medium and an information recording medium, and more particularly, to a method for manufacturing a glass substrate for information recording medium used for manufacturing an information recording medium for a hard disk drive (HDD), and the information recording thereof.
  • the present invention relates to an information recording medium provided with a glass substrate for medium.
  • An information recording medium such as a magnetic disk is mounted on a hard disk drive mounted on a computer or the like.
  • Such an information recording medium is manufactured by providing a magnetic thin film layer for magnetic recording on the main surface of an aluminum or glass substrate.
  • glass substrates have been widely used because high strength and high hardness are required.
  • Such a glass substrate is referred to as an information recording medium glass substrate (hereinafter also simply referred to as a glass substrate).
  • a chemical strengthening treatment is performed on the main surface of the glass substrate in order to further increase the strength (International Publication No. 2008/062657 (Patent Document 1). )reference).
  • the main surface of the glass substrate is strengthened by the chemical strengthening treatment.
  • an information recording medium for a hard disk drive information is recorded by magnetizing a recording layer by a magnetic head, and information is reproduced by reading the recorded magnetic information.
  • a gap also referred to as a flying height
  • DFH Dynamic Flying Height
  • This is a technology that uses a special metal at the location where the recording head is mounted to protrude the head at a fine distance.
  • the flying height due to various external factors (pressure fluctuation, temperature fluctuation, etc.) in the hard disk drive. By correcting the fluctuation by DFH, the flying height can be kept constant, and in principle, the flying height can be set to several nm or less.
  • the chemical strengthening treatment is performed with many deposits remaining on the main surface of the glass substrate, the deposits are firmly fixed on the main surface of the glass substrate by the heat treatment during the chemical strengthening.
  • the adhered deposits make the ion exchange layer non-uniform due to chemical strengthening, resulting in defects on the main surface of the glass substrate.
  • the present invention has been made in view of the above-described circumstances, and manufacture of a glass substrate for an information recording medium capable of suppressing contact between an information recording medium such as a magnetic disk and a data reading head. It is an object of the present invention to provide a method and an information recording medium provided with the glass substrate for the information recording medium.
  • the manufacturing method of the glass substrate for information recording media based on this invention the process of preparing a glass blank material, the process of forming a substantially circular glass substrate using the said glass blank material, and a wrap with respect to the said glass substrate
  • a step of polishing, a step of polishing the glass substrate, and a cleaning of the main surface of the glass substrate remove a plurality of deposits attached to the main surface of the glass substrate.
  • a step of performing a chemical strengthening treatment on the main surface of the glass substrate is
  • the main surface of the glass substrate out of the deposits is irradiated with two wavelengths of laser light in different directions and detected based on the reflected light.
  • the main surface of the glass substrate is cleaned so that the number of deposits having a size of 0.1 ⁇ m or less is 10 or less per 2.5 inch disk.
  • a machining allowance is 0.1 ⁇ m or more and 0.5 ⁇ m or less with respect to the main surface of the glass substrate subjected to chemical strengthening treatment.
  • the method further includes a step of performing a polishing process.
  • An information recording medium based on the present invention comprises a glass substrate obtained by the above-described method for producing a glass substrate for information recording medium based on the present invention, and a magnetic thin film layer formed on the main surface of the glass substrate. .
  • the manufacturing method of the glass substrate for information recording media which can suppress contact with information recording media, such as a magnetic disc, and a data reading head, and information recording provided with the glass substrate for the information recording media A medium can be obtained.
  • FIG. 6 is a flowchart showing a glass substrate cleaning process in Example 2.
  • FIG. 10 is a flowchart showing a glass substrate cleaning process in Example 3.
  • FIG. 10 is a flowchart showing a glass substrate cleaning process in Comparative Example 1.
  • FIG. It is a flowchart figure which shows the washing
  • FIG. 1 is a perspective view showing a glass substrate 1 used for a magnetic disk 10 (see FIG. 2).
  • FIG. 2 is a perspective view showing a magnetic disk 10 provided with a glass substrate 1 as an information recording medium.
  • a glass substrate 1 (glass substrate for information recording medium) used for a magnetic disk 10 has an annular disk shape with a hole 1H formed in the center.
  • the glass substrate 1 has a front main surface 1A, a back main surface 1B, an inner peripheral end surface 1C, and an outer peripheral end surface 1D.
  • the size of the glass substrate 1 is, for example, 0.8 inch, 1.0 inch, 1.8 inch, 2.5 inch, or 3.5 inch.
  • the thickness of the glass substrate is, for example, 0.30 mm to 2.2 mm from the viewpoint of preventing breakage.
  • the glass substrate has an outer diameter of about 64 mm, an inner diameter of about 20 mm, and a thickness of about 0.8 mm.
  • the thickness of the glass substrate is a value calculated by averaging the values measured at a plurality of arbitrary points to be pointed on the glass substrate.
  • the magnetic disk 10 is configured by forming a magnetic thin film layer 2 on the front main surface 1A of the glass substrate 1 described above.
  • the magnetic thin film layer 2 is formed only on the front main surface 1A, but the magnetic thin film layer 2 may also be formed on the back main surface 1B.
  • the magnetic thin film layer 2 is formed by spin-coating a thermosetting resin in which magnetic particles are dispersed on the front main surface 1A of the glass substrate 1 (spin coating method).
  • the magnetic thin film layer 2 may be formed by a sputtering method, an electroless plating method, or the like performed on the front main surface 1A of the glass substrate 1.
  • the film thickness of the magnetic thin film layer 2 formed on the front main surface 1A of the glass substrate 1 is about 0.3 ⁇ m to 1.2 ⁇ m in the case of the spin coating method, about 0.04 ⁇ m to 0.08 ⁇ m in the case of the sputtering method, In the case of the electroless plating method, the thickness is about 0.05 ⁇ m to 0.1 ⁇ m. From the viewpoint of thinning and high density, the magnetic thin film layer 2 is preferably formed by sputtering or electroless plating.
  • the magnetic material used for the magnetic thin film layer 2 is not particularly limited, and a conventionally known material can be used. However, in order to obtain a high coercive force, Co having high crystal anisotropy is basically used for the purpose of adjusting the residual magnetic flux density. A Co-based alloy to which Ni or Cr is added is suitable. Further, as a magnetic layer material suitable for heat-assisted recording, an FePt-based material may be used.
  • a lubricant may be thinly coated on the surface of the magnetic thin film layer 2 in order to improve the sliding of the magnetic recording head.
  • the lubricant include those obtained by diluting perfluoropolyether (PFPE), which is a liquid lubricant, with a solvent such as Freon.
  • an underlayer or a protective layer may be provided.
  • the underlayer in the magnetic disk 10 is selected according to the magnetic film.
  • 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 underlayer is not limited to a single layer, and may have a multi-layer structure in which the same or different layers are stacked.
  • a multilayer underlayer such as Cr / Cr, Cr / CrMo, Cr / CrV, NiAl / Cr, NiAl / CrMo, or NiAl / CrV may be used.
  • Examples of the protective layer for preventing wear and corrosion of the magnetic thin film layer 2 include a Cr layer, a Cr alloy layer, a carbon layer, a hydrogenated carbon layer, a zirconia layer, or a silica layer. These protective layers can be formed continuously with an in-line type sputtering apparatus together with the underlayer and the magnetic film. In addition, these protective layers may be a single layer, or may have a multilayer structure including the same or different layers.
  • Another protective layer may be formed on the protective layer or instead of the protective layer.
  • tetraalkoxylane is diluted with an alcohol-based solvent on a Cr layer, and then colloidal silica fine particles are dispersed and applied, followed by baking to form a silicon oxide (SiO 2 ) layer. It may be formed.
  • Glass substrate manufacturing method Next, the manufacturing method of the glass substrate (glass substrate for information recording media) in this Embodiment is demonstrated using the flowchart figure shown in FIG.
  • the manufacturing method of the glass substrate in this Embodiment is a glass blank material preparation process (step S10), a glass substrate formation process (step S20), a grinding
  • the magnetic thin film forming step (step S60) may be performed on the glass substrate (corresponding to the glass substrate 1 in FIG. 1) obtained through the chemical strengthening treatment step (step S50).
  • the magnetic disk 10 is obtained by the magnetic thin film forming step (step S60).
  • the glass material constituting the glass substrate is melted (step S11).
  • the glass material is, for example, aluminosilicate glass.
  • the molten glass material is poured onto the lower mold and then press-molded with the upper mold and the lower mold (step S12).
  • a disk-shaped glass blank (glass base material) is formed by press molding.
  • the glass blank material may be formed by cutting out a sheet glass (sheet glass) formed by a downdraw method or a float method with a grinding wheel.
  • a lapping process is performed on both main surfaces of the press-molded glass blank (step S21).
  • Both main surfaces of a glass blank material are the main surfaces used as the front main surface 1A and the main surface used as the back main surface 1B in FIG. 1 through each process mentioned later (henceforth, both main surfaces) Also called).
  • the lapping polishing process is performed by pressing a lapping platen such as a double-sided lapping device using a planetary gear mechanism against both main surfaces.
  • the approximate parallelism, flatness, thickness, and the like of the glass substrate are preliminarily adjusted by the lapping process.
  • a coring (inner peripheral cut) process is performed on the center portion of the glass blank using a cylindrical diamond drill or the like (step S22).
  • a coring process is performed on the center portion of the glass blank using a cylindrical diamond drill or the like.
  • a predetermined chamfering process may be performed on the hole in the center.
  • step S30 Similar to step S21 described above, lap polishing is performed on both main surfaces of the glass substrate (step S31).
  • the coring step (step S22) fine scratches and protrusions formed on both main surfaces of the glass substrate are removed.
  • the outer peripheral end surface of the glass substrate is polished into a mirror surface by a brush (step S32).
  • the abrasive grains a slurry containing cerium oxide abrasive grains is used.
  • step S31 the warp of the glass substrate is corrected while removing scratches remaining on both main surfaces of the glass substrate in the lapping process.
  • step S32 a double-side polishing device using a planetary gear mechanism is used.
  • the glass substrate is subjected to polishing again, and micro defects remaining on both main surfaces of the glass substrate are eliminated (step S34). Both main surfaces of the glass substrate are finished to have a mirror-like surface to form a desired flatness, and the warp of the glass substrate is eliminated.
  • a double-side polishing device using a planetary gear mechanism is used. Colloidal silica is used as the abrasive.
  • the glass substrate is cleaned (step S40).
  • the deposits attached to the two main surfaces of the glass substrate are removed.
  • the glass substrate is cleaned until the number of deposits having a size of 0.1 ⁇ m or less is 10 or less per 2.5 inch disk (4 or less per 1 inch disk) on both main surfaces.
  • the glass substrate when the size of the glass substrate as a magnetic disk is a 2.5 inch disk, the glass substrate has a size of 0.1 ⁇ m or less attached on the main surface which is the front main surface 1A in FIG. Washing is performed until the number of deposits having 10 or less and the number of deposits having a size of 0.1 ⁇ m or less attached on the main surface which is the back main surface 1B in FIG. 1 is also 10 or less.
  • size of 0.1 micrometer or less here means the deposit
  • the number of deposits in the present embodiment is calculated as follows, for example.
  • an optical defect inspection apparatus including laser oscillators 3 and 4 and light receivers 5 and 6 that irradiate laser beams 3L and 4L having two wavelengths from different directions is prepared.
  • As an optical defect inspection apparatus that performs OSA (Optical Surface Analyzer) counting for example, OSA7120 manufactured by KLA-Tencor (also possible with OSA7100) can be used.
  • OSA Optical Surface Analyzer
  • KLA-Tencor also possible with OSA7100
  • Laser light 3L having directivity is irradiated from the laser oscillator 3 to the front main surface 1A of the glass substrate 1 (the main surface forming the front main surface 1A through a process described later).
  • the laser beam 3L has a wavelength of 660 nm, a spot size on the front main surface 1A of 6 ⁇ m ⁇ 5 ⁇ m, and an incident angle of about 15 ° (substantially vertical).
  • the laser oscillator 4 irradiates the front main surface 1A of the glass substrate 1 with laser light 4L having directivity from a direction different from the laser light 3L.
  • the laser light 4L has a wavelength of 405 nm, a spot size on the front main surface 1A of 6 ⁇ m ⁇ 5 ⁇ m, and an incident angle of about 70 ° (oblique incidence).
  • the light receivers 5 and 6 receive the reflected light (scattered light) of the laser beams 3L and 4L reflected on the front main surface 1A of the glass substrate 1.
  • the optical defect inspection apparatus performs a predetermined calculation based on the light energy of the laser beams 3L and 4L received by the light receivers 5 and 6. By this calculation, the optical defect inspection apparatus calculates the number of deposits having a size of 0.1 ⁇ m or less attached on the front main surface 1A of the glass substrate 1. Similarly to the front main surface 1A of the glass substrate 1, the number of deposits is calculated for the back main surface 1B of the glass substrate 1 by an optical defect inspection apparatus.
  • the reflected light (scattered light) having a wavelength of 405 nm is received by a light receiver 7 different from the light receiver 5 and is calculated, thereby calculating the front main surface 1A (or the back surface) with higher accuracy. It is possible to calculate the number of deposits having a size of 0.1 ⁇ m or less adhering to the surface 1B).
  • calculation of the number of deposits is not included in the essential process.
  • the calculation of the number of deposits may be performed only at an initial stage where the setting conditions of each manufacturing facility (component device) used for manufacturing the glass substrate are determined.
  • the number of deposits may be calculated every time a predetermined number of glass substrates are manufactured, and the result may be reflected in the setting of each manufacturing facility (component device).
  • step S50 Chemical strengthening process
  • a mixed solution of potassium nitrate (content 70%) and sodium nitrate (content 30%) is used.
  • the alkali metal ions such as lithium ions and sodium ions contained in the glass substrate are replaced with alkali metal ions such as potassium ions having a larger ion radius than these ions (ion exchange method). Compressive stress is generated in the ion-exchanged region due to the strain caused by the difference in ion radius, and both main surfaces of the glass substrate are strengthened. As described above, a glass substrate corresponding to the glass substrate 1 shown in FIG. 1 is obtained.
  • the glass substrate 1 may be further subjected to a polishing polishing process in which the machining allowance on both main surfaces is 0.1 ⁇ m or more and 0.5 ⁇ m or less.
  • a polishing polishing process in which the machining allowance on both main surfaces is 0.1 ⁇ m or more and 0.5 ⁇ m or less.
  • Magnetic thin film layers are formed on both main surfaces (or any one of the main surfaces) of the glass substrate (corresponding to the glass substrate 1 shown in FIG. 1) on which the chemical strengthening treatment has been completed.
  • the magnetic thin film layer includes an adhesion layer made of a Cr alloy, a soft magnetic layer made of a CoFeZr alloy, an orientation control underlayer made of Ru, a perpendicular magnetic recording layer made of a CoCrPt alloy, a protective layer made of a C system, and a lubrication made of an F system. It is formed by sequentially depositing layers. By forming the magnetic thin film layer, a perpendicular magnetic recording disk corresponding to the magnetic disk 10 shown in FIG. 2 can be obtained.
  • the magnetic disk in the present embodiment is an example of a perpendicular magnetic disk composed of a magnetic thin film layer.
  • the magnetic disk may be composed of a magnetic layer or the like as a so-called in-plane magnetic disk.
  • the glass substrate is used until the number of deposits having a size of 0.1 ⁇ m or less detected by the above detection method is 10 or less per 2.5 inch disk on both main surfaces. Washed.
  • the method for manufacturing glass substrate 1 (glass substrate for information recording medium) in the present embodiment the occurrence of defects due to the fact that deposits are firmly fixed on the main surface of the glass substrate is suppressed. Since the remaining number of deposits on the main surface of the glass substrate is 10 or less per 2.5 inch disk, the chemical strengthening treatment can be performed uniformly on the main surface of the glass substrate. The occurrence of defects on the main surface is also suppressed.
  • the glass substrate is improved in impact resistance and vibration resistance by the chemical strengthening treatment on the glass substrate. It is also possible to prevent the substrate from being damaged.
  • the magnetic disk 10 provided with the glass substrate 1 obtained by the method for manufacturing the glass substrate 1 (glass substrate for information recording medium) in the present embodiment is prevented from coming into contact with the data reading head, and data reading errors are caused.
  • production etc. can also be suppressed.
  • the information recording medium provided with the glass substrate 1 is used as a hard disk, it is possible to ensure operational stability.
  • the number of deposits is 10 or less per 2.5 inch disk with respect to both main surfaces (corresponding to the front main surface 1A and the back main surface 1B) of the glass substrate. It demonstrated based on the aspect that a glass substrate was wash
  • the number of deposits is 10 or less per 2.5 inch disk only on the main surface on which the magnetic thin film layer 2 (see FIG. 2) is formed (the main surface facing the data reading head). The glass substrate may be cleaned so as to be.
  • Examples and Comparative Examples Hereinafter, examples (Examples 1 to 3) and comparative examples (Comparative Examples 1 and 2) performed on the basis of the above-described embodiment will be described with reference to FIGS.
  • a cleaning process (details will be described later) corresponding to the cleaning process (Step S40) in the above-described embodiment is performed on one main surface of the glass substrate.
  • the number of deposits on the surface was calculated as the number of OSA (Optical Surface Analyzer) encounters.
  • FIG. 5 is a flowchart showing each process of the cleaning process (step S40A) in the first embodiment.
  • FIG. 6 is a flowchart illustrating each process of the cleaning process (step S40B) in the second embodiment.
  • FIG. 7 is a flowchart showing each process of the cleaning process (step S40C) in the third embodiment.
  • FIG. 8 is a flowchart showing each process of the cleaning process (step S40Y) in the first comparative example.
  • FIG. 9 is a flowchart illustrating each process of the cleaning process (step S40Z) in the second comparative example.
  • FIG. 10 is a diagram showing the number of deposits on the main surface of the glass substrate after the respective cleaning steps in Examples 1 to 3 and Comparative Examples 1 and 2 as the number of OSA (Optical Surface Analyzer) encounters. is there.
  • the number of deposits shown in FIG. 10 is a value obtained by the same calculation method as in the above-described embodiment using an optical defect inspection apparatus.
  • Example 1 Referring to FIG. 5, in Example 1, the following cleaning process (Step S40A) is performed on the main surface of the glass substrate as the cleaning process (Step S40) in the above-described embodiment (see FIG. 3). did.
  • step S40A the detergent cleaning process 1 (step S41A), the detergent cleaning process 2 (step S42A), the ozone water cleaning process (step S43A), the pure water cleaning process 1 (step S44A), The pure water cleaning process 2 (step S45A), the IPA cleaning process (step S46A), the IPA vapor drying process (step S47A), and the UV ozone cleaning process (step S48A) were sequentially performed.
  • step S41A the detergent cleaning process 1
  • step S42A the detergent cleaning process 2
  • step S43A the ozone water cleaning process
  • step S43A the pure water cleaning process 1
  • step S44A The pure water cleaning process 2 (step S45A), the IPA cleaning process (step S46A), the IPA vapor drying process (step S47A), and the UV ozone cleaning process (step S48A) were sequentially performed.
  • step S45A the IPA cleaning process
  • step S47A the IPA vapor drying process
  • step S48A UV ozone cleaning process
  • step S41A cleaning was performed by irradiating an ultrasonic wave of 80 kHz for 5 minutes in a state where the glass substrate was immersed in a cleaning tank storing an alkaline detergent having a concentration of 3% and pH 11 as a detergent.
  • step S42A the glass substrate is immersed in a cleaning tank in which an alkaline detergent having a concentration of 3% and a pH of 11 (a detergent similar to the detergent cleaning process 1) is stored as a detergent for 5 minutes at 950 kHz. Cleaning was performed by irradiating with ultrasonic waves.
  • step S43A cleaning was performed by irradiating 950 kHz ultrasonic waves for 5 minutes in a state where the glass substrate was immersed in a cleaning tank storing ozone water.
  • step S44A cleaning was performed by irradiating a 950 kHz ultrasonic wave for 5 minutes in a state where the glass substrate was immersed in a cleaning tank storing pure water.
  • step S45A cleaning was performed by irradiating an ultrasonic wave of 80 kHz for 5 minutes in a state where the glass substrate was immersed in a cleaning tank storing pure water.
  • step S46A cleaning was performed by immersing the glass substrate in a cleaning tank storing IPA (isopropyl alcohol).
  • step S47A steam drying by IPA was performed.
  • step S48A cleaning was performed by irradiating both main surfaces of the glass substrate 1 with ultraviolet rays using a low-pressure mercury lamp.
  • step S40A When the number of deposits having a size of 0.1 ⁇ m or less on the main surface of the glass substrate that had undergone these cleaning steps (step S40A) in Example 1 was detected, it was 10 per 2.5 inch disk (FIG. 10). reference).
  • a magnetic disk was manufactured using the glass substrate obtained through the cleaning process (step S40A) in Example 1, and this magnetic disk was mounted on a load / unload type hard disk device to perform a durability test.
  • a magnetic head using a GMR (Giant Magneto Resistance) element was used, and the flying height of the magnetic head was 10 nm, and load / unload operations were repeated.
  • the magnetic disk can operate normally without failure even with a load / unload operation of 1 million times. Was confirmed.
  • Example 2 Referring to FIG. 6, in Example 2, the following cleaning process (Step S40B) is performed on the main surface of the glass substrate as the cleaning process (Step S40) in the above-described embodiment (see FIG. 3). did.
  • step S40B the detergent cleaning process 1 (step S41B), the detergent cleaning process 2 (step S42B), the ozone water cleaning process (step S43B), the pure water cleaning process 1 (step S44B), The pure water cleaning process 2 (step S45B), the IPA cleaning process (step S46B), the IPA vapor drying process (step S47B), and the plasma cleaning process (step S48B) were sequentially performed.
  • step S48B In the plasma cleaning step (step S48B), first, the glass substrate was placed in a vacuum chamber, and then the pressure in the vacuum chamber was set to 1 ⁇ 10 ⁇ 3 Pa or less. Next, oxygen at a flow rate of 10 sccm and argon at a flow rate of 3 sccm were introduced into the vacuum chamber, and the pressure in the vacuum chamber was set to 1.0 Pa. Plasma was generated by applying a DC 300 W power, and the main surface of the glass substrate was cleaned for 3 minutes.
  • step S40B When the number of deposits having a size of 0.1 ⁇ m or less on the main surface of the glass substrate that had undergone these cleaning steps (step S40B) in Example 2 was detected, it was 8 per 2.5 inch disk (FIG. 10). reference).
  • a magnetic disk is manufactured using the glass substrate obtained through the cleaning process (step S40B) in the second embodiment, and this magnetic disk is mounted on a load / unload type hard disk device, and the same durability as in the first embodiment.
  • a test was conducted. According to the magnetic disk manufactured by using the glass substrate obtained through the cleaning process (step S40B) in the second embodiment, as in the first embodiment, the load / unload operation fails for 1 million times. It was confirmed that it works normally without any problems.
  • Example 3 Referring to FIG. 7, in the cleaning process of Example 3 (Step S40C), first, a cleaning process having the same contents as the cleaning process (Step S40A) of Example 1 described above (see FIG. 5) was performed ( Step S41C). Next, after performing the chemical strengthening process (step S50) similar to the above-described embodiment on the glass substrate that has been cleaned, the following polishing process (step S42C) is performed on the main surface of the glass substrate. Carried out.
  • step S42C a double-side polishing apparatus having a planetary gear mechanism was used. Polishing treatment was performed on the main surface of the glass substrate so that the machining allowance on the main surface was 0.1 ⁇ m or more and 0.5 ⁇ m or less. Colloidal silica was used as the abrasive.
  • step S40C When the number of deposits having a size of 0.1 ⁇ m or less on the main surface of the glass substrate that had undergone these cleaning steps (step S40C) in Example 3 was detected, it was 3 per 2.5 inch disk (FIG. 10). reference).
  • a magnetic disk is manufactured using the glass substrate obtained through the cleaning process (step S40C) in Example 3, and this magnetic disk is mounted on a load / unload type hard disk device, and the same durability as in Example 1 is obtained. A test was conducted. According to the magnetic disk manufactured using the glass substrate obtained through the cleaning process (step S40C) in Example 3, it can operate normally without failure with respect to the load / unload operations of 3 million times. confirmed.
  • Comparative Example 1 Referring to FIG. 8, in Comparative Example 1, the following cleaning process (step S40Y) is performed on the main surface of the glass substrate as the cleaning process (step S40) in the above-described embodiment (see FIG. 3). did.
  • step S40Y In the cleaning process (step S40Y) in Comparative Example 1, the detergent cleaning process 1 (step S41Y), the detergent cleaning process 2 (step S42Y), the pure water cleaning process 1 (step S43Y), and the pure water cleaning process 2 (step S44Y).
  • the IPA cleaning step (step S45Y) and the IPA vapor drying step (step S46Y) were sequentially performed. Hereinafter, details of each process will be described in order.
  • step S41Y In the detergent cleaning process 1 (step S41Y), the same cleaning as the detergent cleaning process 1 (step S41A) in Example 1 (see FIG. 5) described above was performed.
  • step S42Y In the detergent cleaning process 2 (step S42Y), the cleaning is performed in the same manner as the detergent cleaning process 2 (step S42A) in the above-described embodiment 1 (see FIG. 5) except that an ultrasonic wave of 80 kHz is irradiated. I did it.
  • step S43Y cleaning was performed in the same manner as in the detergent cleaning process 3 (step S44A) in Example 1 (see FIG. 5) described above.
  • the pure water cleaning process 2 (step S44Y) has the same contents as the pure water cleaning process 2 (step S45A) in the first embodiment (see FIG. 5) except that 80 kHz ultrasonic waves are irradiated. Washing was performed.
  • the IPA cleaning step (step S45Y) and the IPA vapor drying step (step S46Y) are the same as the IPA cleaning step (step S46A) and the IPA vapor drying step (step S47A) in Example 1 (see FIG. 5), respectively.
  • the contents were washed and dried.
  • step S40Y The number of deposits having a size of 0.1 ⁇ m or less on the main surface of the glass substrate that had undergone these cleaning steps (step S40Y) in Comparative Example 1 was 30 per 2.5 inch disk (FIG. 10). reference).
  • a magnetic disk is manufactured using the glass substrate obtained through the cleaning process (step S40Y) in Comparative Example 1, and this magnetic disk is mounted on a load / unload type hard disk device, and the same durability as in Example 1 is obtained.
  • a test was conducted.
  • an operation failure such as a head crash occurred in the load / unload operation of 500,000 times.
  • this cause it is considered that the deposit remained on the main surface of the glass substrate even after the glass substrate was formed as a magnetic disk, and this malfunction caused the deposit.
  • Comparative Example 2 Referring to FIG. 9, in Comparative Example 2, the following cleaning process (step S40Z) is performed on the main surface of the glass substrate as the cleaning process (step S40) in the above-described embodiment (see FIG. 3). did.
  • step S40Z In the cleaning process (step S40Z) in Comparative Example 2, the detergent cleaning process 1 (step S41Z), the detergent cleaning process 2 (step S42Z), the pure water cleaning process 1 (step S43Z), and the pure water cleaning process 2 (step S44Z).
  • the IPA cleaning process (step S45Z) and the IPA vapor drying process (step S46Z) were sequentially performed. Hereinafter, details of each process will be described in order.
  • step S41Z the cleaning is performed in the same manner as the detergent cleaning process 1 (step S41Y) in the comparative example 1 described above (see FIG. 8) except that the ultrasonic wave is irradiated for 10 minutes. I did it.
  • step S42Z the cleaning is performed in the same manner as the detergent cleaning process 2 (step S42Y) in the above-described comparative example 1 (see FIG. 8) except that ultrasonic waves are irradiated for 10 minutes. I did it.
  • the cleaning process has the same contents as the detergent cleaning process 3 (step S43Y) in the above-described comparative example 1 (see FIG. 8) except that the ultrasonic wave is irradiated for 10 minutes.
  • the pure water cleaning process 2 (step S44Z) has the same contents as the pure water cleaning process 2 (step S44Y) in the above-described comparative example 1 (see FIG. 8) except that the ultrasonic wave is irradiated for 10 minutes. Washing was performed.
  • step S45Z In the IPA cleaning process (step S45Z) and the IPA vapor drying process (step S46Z), the IPA cleaning process (step S45Y) and the IPA vapor drying process (step S46Y) in Comparative Example 1 (see FIG. 8) described above have the same contents, respectively. Was washed and dried.
  • step S40Z The number of deposits having a size of 0.1 ⁇ m or less on the main surface of the glass substrate that had undergone these cleaning steps (step S40Z) in the comparative example was 11 per 2.5 inch disk (see FIG. 10). ).
  • a magnetic disk is manufactured using the glass substrate obtained through the cleaning process (step S40Y) in the comparative example, and this magnetic disk is mounted on a load / unload type hard disk device, and the durability test is the same as in Example 1.
  • a malfunction such as a head crash occurred after 1 million load / unload operations. Regarding this cause, it is considered that the deposit remained on the main surface of the glass substrate even after the glass substrate was formed as a magnetic disk, and this malfunction caused the deposit.
  • both main surfaces of the glass substrate is preferably cleaned so that the number of deposits having a size of 0.1 ⁇ m or less is 10 or less per 2.5 inch disk.
  • the ozone water cleaning process (step S43A), the UV ozone cleaning process (step S48A) including the cleaning process (step S40A), the ozone water cleaning process (step S43B), and plasma are preferably employed.
  • 1 glass substrate 1A front main surface, 1B back main surface, 1C inner peripheral end surface, 1D outer peripheral end surface, 1H hole, 2 magnetic thin film layer, 3, 4 laser oscillator, 3L, 4L laser light, 5, 6, 7 light receiver 10 Magnetic disk.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacturing Of Magnetic Record Carriers (AREA)

Abstract

Un procédé de production d'un substrat en verre destiné à être utilisé dans un support d'enregistrement d'informations consiste à préparer un verre blanc (S10), former un substrat en verre pratiquement circulaire à l'aide du verre blanc (S20), exécuter un traitement de rodage sur le substrat en verre (S31), exécuter des traitements de polissage sur le substrat en verre (S33, S34), supprimer de multiples dépôts qui ont adhéré à la surface principale du substrat en verre en nettoyant la surface principale du substrat en verre (S40), et exécuter un traitement de renforcement chimique sur la surface principale du substrat en verre (S50). La surface principale du substrat en verre est lavée de sorte que le nombre de dépôts ayant une taille inférieure à 0,1 μm soit inférieur à 10 par disque de 2,5 pouces, les dépôts étant détectés sur la base des rayons respectifs qu'ils réfléchissent lors de l'irradiation de la surface principale du substrat en verre selon différentes directions avec une lumière laser de deux longueurs d'onde.
PCT/JP2011/071421 2010-09-30 2011-09-21 Procédé de production d'un substrat en verre à utiliser dans un support d'enregistrement d'informations et support d'enregistrement d'informations WO2012043314A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04170715A (ja) * 1990-11-02 1992-06-18 Tdk Corp 磁気ディスク用ガラス基板
JP2004335081A (ja) * 2003-04-18 2004-11-25 Hoya Corp 磁気ディスク用ガラス基板の洗浄方法及び磁気ディスク用ガラス基板の製造方法並びに磁気ディスクの製造方法
JP2006268904A (ja) * 2005-03-22 2006-10-05 Konica Minolta Opto Inc 磁気記録媒体用ガラス基板の製造方法
JP2009238294A (ja) * 2008-03-26 2009-10-15 Hoya Glass Disk Thailand Ltd 磁気ディスク用ガラス基板の製造方法、磁気ディスク用ガラス基板および磁気ディスク
JP2009245516A (ja) * 2008-03-31 2009-10-22 Hoya Corp 磁気ディスクの製造方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04170715A (ja) * 1990-11-02 1992-06-18 Tdk Corp 磁気ディスク用ガラス基板
JP2004335081A (ja) * 2003-04-18 2004-11-25 Hoya Corp 磁気ディスク用ガラス基板の洗浄方法及び磁気ディスク用ガラス基板の製造方法並びに磁気ディスクの製造方法
JP2006268904A (ja) * 2005-03-22 2006-10-05 Konica Minolta Opto Inc 磁気記録媒体用ガラス基板の製造方法
JP2009238294A (ja) * 2008-03-26 2009-10-15 Hoya Glass Disk Thailand Ltd 磁気ディスク用ガラス基板の製造方法、磁気ディスク用ガラス基板および磁気ディスク
JP2009245516A (ja) * 2008-03-31 2009-10-22 Hoya Corp 磁気ディスクの製造方法

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