WO2013099729A1 - 情報記録媒体用ガラス基板の製造方法 - Google Patents
情報記録媒体用ガラス基板の製造方法 Download PDFInfo
- Publication number
- WO2013099729A1 WO2013099729A1 PCT/JP2012/082897 JP2012082897W WO2013099729A1 WO 2013099729 A1 WO2013099729 A1 WO 2013099729A1 JP 2012082897 W JP2012082897 W JP 2012082897W WO 2013099729 A1 WO2013099729 A1 WO 2013099729A1
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- WO
- WIPO (PCT)
- Prior art keywords
- glass substrate
- cleaning
- tank
- information recording
- recording medium
- Prior art date
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
- B08B3/04—Cleaning involving contact with liquid
- B08B3/10—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
- B08B3/12—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration by sonic or ultrasonic vibrations
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/04—Lapping machines or devices; Accessories designed for working plane surfaces
- B24B37/07—Lapping machines or devices; Accessories designed for working plane surfaces characterised by the movement of the work or lapping tool
- B24B37/08—Lapping machines or devices; Accessories designed for working plane surfaces characterised by the movement of the work or lapping tool for double side lapping
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B9/00—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor
- B24B9/02—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground
- B24B9/06—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain
- B24B9/065—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of thin, brittle parts, e.g. semiconductors, wafers
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C23/00—Other surface treatment of glass not in the form of fibres or filaments
- C03C23/0075—Cleaning of glass
-
- 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 producing a glass substrate for an information recording medium.
- an aluminum substrate or a glass substrate is used as an information recording medium (magnetic disk recording medium) used in a computer or the like.
- a magnetic thin film layer is formed on these substrates, and information is recorded on the magnetic thin film layer by magnetizing the magnetic thin film layer with a magnetic head.
- hard disk drives have been developed that have a recording capacity of 500 GB (single-sided 250 GB), a surface recording density of 630 Gb / square inch or more, with one 2.5-inch recording medium. The distance (flying height) between the head and the information recording medium is further reduced.
- the size of defects on the substrate surface permitted as the information recording medium is also reduced in order to suppress defects (head crashes) when the information recording medium is used in a hard disk drive.
- the demands on the size and the number are increasing.
- a device has been devised to reduce defects in the information recording medium glass substrate by devising polishing and cleaning methods for the information recording medium glass substrate.
- DFH Dynamic Flying Height
- Patent Document 1 Japanese Patent Application Laid-Open No. 2007-268448 ( Patent Document 1)).
- the glass substrate for the information recording medium was cleaned using ultrasonic cleaning using a quartz tank, it was found that surface defects due to cleaning unevenness occurred.
- the quartz tank is very clean, it needs to be a relatively thick tank in order to obtain rigidity, and since it greatly affects the attenuation rate due to the incident angle of ultrasonic waves, there is a partial cleaning residue.
- a glass substrate for an information recording medium which is generated and requires strict accuracy, becomes a problem.
- the problem to be solved by the present invention is that there is an increasing demand for reducing defects in the glass substrate for information recording medium in the process of manufacturing the glass substrate for information recording medium.
- the high cleanability and high smoothness means high cleaning that does not cause any fluctuations in the surface state due to deposits originating from the polishing process that cause deterioration of the smoothness and impurities generated during cleaning. It means that sex is required.
- the present invention has been made in view of the above circumstances, and provides a method for manufacturing a glass substrate for an information recording medium capable of reducing defects that occur during the manufacturing process of the glass substrate for an information recording medium. Objective.
- the method for manufacturing a glass substrate for an information recording medium includes a step of polishing a glass substrate and a step of cleaning the glass substrate after polishing the glass substrate.
- the step of cleaning the glass substrate includes a step of cleaning the glass substrate in a plurality of first tanks whose inner surface is made of stainless steel or resin, and a second tank in which the inner surface of the tank is made of quartz. Cleaning the glass substrate.
- Each step of cleaning the glass substrate in the plurality of first tanks includes at least one ultrasonic cleaning.
- the step of cleaning the glass substrate in the second tank is performed after the steps of cleaning the glass substrate in the plurality of first tanks are completed.
- the step of cleaning the glass substrate is performed on the glass substrate before performing the step of cleaning the glass substrate in the second tank. Including a step of scrub cleaning.
- the step of cleaning the glass substrate in the second tank includes applying an ultrasonic wave having a frequency of 900 kHz or more to the glass substrate.
- the step of cleaning the glass substrate in each of the plurality of first tanks applies an ultrasonic wave having a frequency of 78 kHz to 500 kHz to the glass substrate. Including doing.
- the step of cleaning the glass substrate in the second tank includes applying an ultrasonic wave having a first frequency to the glass substrate.
- Each of the steps of cleaning the glass substrate in the first tank includes applying an ultrasonic wave having a second frequency lower than the first frequency to the glass substrate.
- the present invention it is possible to reduce defects that occur in the manufacturing process of the glass substrate for information recording media.
- FIG. 3 is a diagram schematically showing a cleaning apparatus for performing each cleaning process according to Examples 1 to 3 and Comparative Examples 1 to 3 of the present invention.
- FIG. 1 is a perspective view of an information recording medium glass substrate 1G
- FIG. 2 is a perspective view of the information recording medium.
- an information recording medium glass substrate 1G used for the information recording medium 1 (hereinafter referred to as “glass substrate 1G”) has an annular disk shape with a hole 11 formed in the center. ing.
- the glass substrate 1G has an outer peripheral end face 12, an inner peripheral end face 13, a front main surface 14, and a back main surface 15.
- amorphous glass or the like is used as the glass substrate 1G.
- the outer diameter is about 65 mm
- the inner diameter is about 20 mm
- the thickness is about 0.8 mm
- the surface roughness is about 2.0 mm or less.
- the inch size of the glass substrate 1G is not particularly limited, and various glass substrates 1G of 0.8 inch, 1.0 inch, 1.8 inch, 2.5 inch, and 3.5 inch are manufactured as disks for information recording media. May be.
- the thickness of the glass substrate 1G is preferably 0.30 mm to 2.2 mm because it is effective against cracking of the glass substrate 1G due to drop impact.
- the thickness of the glass substrate 1 ⁇ / b> G here means an average value of values measured at some arbitrary points to be pointed on the substrate.
- a magnetic thin film layer 23 is formed on the front main surface 14 of the glass substrate 1G.
- the magnetic thin film layer 23 is formed only on the front main surface 14, but it is also possible to provide the magnetic thin film layer 23 on the back main surface 15.
- a conventionally known method can be used as a method for forming the magnetic thin film layer 23 .
- a method of spin-coating a thermosetting resin in which magnetic particles are dispersed a method of forming by sputtering, a method of electroless The method of forming by plating is mentioned.
- the film thickness by spin coating is about 0.3 to 1.2 ⁇ m
- the film thickness by sputtering is about 0.04 to 0.08 ⁇ m
- the film thickness by electroless plating is 0.05 to 0.1 ⁇ m. From the viewpoint of thinning and high density, film formation by sputtering and electroless plating is preferable.
- the magnetic material used for the magnetic thin film layer 23 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. Co-based alloys to which Ni and Cr are added are suitable. In recent years, FePt-based materials have been used as magnetic layer materials suitable for heat-assisted recording.
- the surface of the magnetic thin film layer 23 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.
- the underlayer in the information recording medium 1 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 23 include a Cr layer, a Cr alloy layer, a carbon layer, a hydrogenated carbon layer, a zirconia layer, and a silica layer.
- the protective layer can be formed continuously with an in-line sputtering apparatus, such as an underlayer and a magnetic film.
- the protective layer may be a single layer, or may have a multilayer structure composed of 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.
- FIG. 3 is a flowchart showing a method for manufacturing the glass substrate 1G and the information recording medium 1.
- step 10 a “glass melting step” of step 10 (hereinafter abbreviated as “S10”, the same applies to step 11 and subsequent steps), the glass material constituting the glass substrate is melted.
- a glass substrate was produced by pressing the molten glass material using an upper mold and a lower mold.
- the glass composition used was a general aluminosilicate glass.
- the method for producing the glass substrate is not limited to molding, and may be cut out from plate glass, which is a known technique, and the glass composition is not limited thereto.
- both main surfaces of the glass substrate were lapped.
- This first lapping step was performed using a double-sided lapping device using a planetary gear mechanism. Specifically, the lapping platen was pressed on both surfaces of the glass substrate from above and below, the grinding liquid was supplied onto the main surface of the glass substrate, and these were moved relatively to perform lapping. By this lapping process, a glass substrate having a substantially flat main surface was obtained.
- a hole was formed in the center of the glass substrate using a cylindrical diamond drill to produce an annular glass substrate.
- the inner peripheral end surface and the outer peripheral end surface of the glass substrate were ground with a diamond grindstone, and a predetermined chamfering process was performed.
- the fine uneven shape formed on the main surface in the coring and end face processing in the previous step can be removed in advance. As a result, the polishing time of the main surface in the subsequent process can be shortened.
- the outer peripheral end surface of the glass substrate was subjected to mirror polishing by brush polishing.
- a slurry containing general cerium oxide abrasive grains was used as the abrasive grains.
- the main surface was polished.
- the first polishing step is mainly intended to correct scratches and warpage remaining on the main surface in the first and second lapping steps (S12, S14) described above.
- the main surface was polished by a double-side polishing apparatus having a planetary gear mechanism.
- the abrasive general cerium oxide abrasive grains were used.
- a surface reinforcing layer was formed on the main surface of the glass substrate 1G.
- chemical strengthening was performed by immersing the glass substrate 1G in a mixed solution of potassium nitrate (70%) and sodium nitrate (30%) heated to 300 ° C. for about 30 minutes.
- the lithium ion and sodium ion on the inner peripheral end surface and outer peripheral end surface of the glass substrate are respectively replaced with sodium ions and potassium ions in the chemical strengthening solution, and a compressive stress layer is formed, thereby forming the main surface of the glass substrate and The end face was strengthened.
- the main surface polishing step was performed in the “second polishing step” of S18.
- This second polishing step aims to eliminate the fine defects on the main surface that have been generated and remain in the above-described steps and finish it in a mirror shape, to eliminate warpage and finish it to a desired flatness.
- polishing was performed by a double-side polishing apparatus having a planetary gear mechanism.
- abrasive colloidal silica having an average particle diameter of about 20 nm was used to obtain a smooth surface.
- an adhesion layer made of a Cr alloy, a soft magnetic layer made of a CoFeZr alloy, Ru An information recording medium of a perpendicular magnetic recording system was manufactured by sequentially forming an orientation control underlayer made of, a perpendicular magnetic recording layer made of a CoCrPt alloy, a C-based protective layer, and an F-based lubricating layer.
- This configuration is an example of a configuration of a perpendicular magnetic recording system, and a magnetic layer or the like may be configured as an in-plane information recording medium.
- the “post-heat treatment step” of S21 is performed to complete the information recording medium.
- the final cleaning step (S19) includes a step of cleaning the glass substrate in a first tank whose inner surface (surface in contact with the cleaning liquid) is made of stainless steel or resin, and a second tank whose inner surface is made of quartz. And a step of cleaning the glass substrate.
- a plurality of first tanks are provided, and the glass substrate is cleaned in each of the plurality of first tanks.
- a plurality of second tanks may be provided or one tank may be provided.
- the cleaning tank whose inner surface is made of stainless steel, resin, and quartz may be referred to as a stainless steel tank, a resin tank, and a quartz tank, respectively.
- the first tank is a tank made entirely of stainless steel, or is a tank made by coating resin on the inner surface of a tank made entirely of stainless steel
- the second tank is a tank made entirely of quartz.
- a tank made entirely of resin may be used as the resin layer, or a double-layer structure in which a propagation liquid is placed in an outer tank made of stainless steel and an inner tank made of quartz is provided in the propagation liquid (outside An ultrasonic generator is attached to the outer surface of the tank, and a cleaning solution is put into the inner tank).
- Each step of cleaning the glass substrate in the first tank includes at least one ultrasonic cleaning.
- the step of cleaning the glass substrate in the second tank is performed after the steps of cleaning the glass substrate in the plurality of first tanks are completed.
- a step of scrub cleaning the glass substrate may be provided before the step of cleaning the glass substrate in the second tank.
- the resin constituting the first tank examples include polyvinyl chloride, polytetrafluoroethylene, polypropylene, and polycarbonate. Further, typically, the thickness of the first tank is, for example, about 0.03 ⁇ m or more and 0.6 ⁇ m or less, and the thickness of the second tank is typically larger than the thickness of the first tank, for example, 1 cm or more. It is about 3 cm or less.
- ultrasonic cleaning is performed at a relatively low frequency (for example, 78 kHz or more and 500 kHz or less) in order to remove a relatively large deposit.
- a relatively low frequency for example, 78 kHz or more and 500 kHz or less
- the attenuation rate of ultrasonic waves is relatively small, it is possible to effectively remove deposits attached to the glass substrate in the polishing step (S15, S16, S18).
- the quartz tank has a large variation in the thickness of the vibration plate in the ultrasonic cleaning. It has been found that this is likely to occur.
- the idea of first performing ultrasonic cleaning in a stainless steel tank or resin tank and then performing final cleaning in a quartz tank is employed.
- the quartz tank is subjected to ultrasonic cleaning at a frequency (for example, 900 kHz or more) higher than that of the stainless steel tank or the resin tank.
- the deposits derived from the polishing process are removed by cleaning in the first tank (stainless steel tank or resin tank).
- the deposits derived from the cleaning tank can be removed by cleaning in the second tank (quartz tank).
- the cleaning process is performed in a cleaning tank consisting of a total of 6 tanks.
- a cleaning tank consisting of a total of 6 tanks.
- cleaning was performed under the same conditions except for the material of the cleaning tank.
- the resin layer in Table 1 is obtained by coating the inner surface of a stainless steel tank with polyvinyl chloride (PVC), and the stainless steel tank and the quartz tank are made of stainless steel and quartz, respectively.
- PVC polyvinyl chloride
- the electromagnetic conversion characteristic inspection is similar to recording / reproduction of a normal hard disk drive, in which a predetermined signal is recorded on a magnetic recording medium with a magnetic head, and then the signal is reproduced. By detecting the recording failure of the recording medium, the quality of the magnetic recording medium, such as the electrical characteristics of the magnetic recording medium and the presence or absence of defects, is confirmed.
- Examples 1 ′ to 3 ′ and Comparative Examples 1 ′ to 3 ′ For each of the examples and comparative examples, 100 glass substrates were evaluated. The number of defects was measured by the same method as in Examples 1 to 3 and Comparative Examples 1 to 3. The results are shown in Table 4 below.
- the present invention is applicable to a method for manufacturing a glass substrate for an information recording medium.
- 1 information recording medium 1G glass substrate for information recording medium, 11 holes, 12 outer peripheral end face, 13 inner peripheral end face, 14 front main surface, 15 back main surface, 23 magnetic thin film layer.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Ceramic Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Manufacturing Of Magnetic Record Carriers (AREA)
- Cleaning In General (AREA)
- Cleaning By Liquid Or Steam (AREA)
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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JP2013551647A JP6105488B2 (ja) | 2011-12-28 | 2012-12-19 | 情報記録媒体用ガラス基板の製造方法 |
CN201280062443.2A CN104160444B (zh) | 2011-12-28 | 2012-12-19 | 信息记录介质用玻璃基板的制造方法 |
Applications Claiming Priority (2)
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JP2011-289079 | 2011-12-28 | ||
JP2011289079 | 2011-12-28 |
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WO2013099729A1 true WO2013099729A1 (ja) | 2013-07-04 |
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PCT/JP2012/082897 WO2013099729A1 (ja) | 2011-12-28 | 2012-12-19 | 情報記録媒体用ガラス基板の製造方法 |
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JP (1) | JP6105488B2 (zh) |
CN (1) | CN104160444B (zh) |
WO (1) | WO2013099729A1 (zh) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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CN106269692A (zh) * | 2016-08-19 | 2017-01-04 | 湖北仁齐科技有限公司 | 一种cnc玻璃盖板的清洗方法 |
Families Citing this family (2)
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CN104616672B (zh) * | 2015-01-22 | 2017-08-11 | 上海光和光学制造股份有限公司 | 一种玻璃母盘基片的制造工艺 |
CN107096782A (zh) * | 2017-05-20 | 2017-08-29 | 合肥市惠科精密模具有限公司 | 一种MicroLED玻璃基板超声波清洗方法 |
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JP2001098298A (ja) * | 1999-09-27 | 2001-04-10 | Hitachi Plant Eng & Constr Co Ltd | アルミノシリケートガラス基板又はセラミックガラス基板の洗浄液及び洗浄方法 |
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 |
JP2008043842A (ja) * | 2006-08-11 | 2008-02-28 | Kaijo Corp | 超音波洗浄装置 |
JP2008243342A (ja) * | 2007-03-29 | 2008-10-09 | Hoya Corp | 磁気ディスク用ガラス基板の超音波洗浄装置および超音波洗浄方法、磁気ディスク製造方法ならびに磁気ディスク |
Family Cites Families (3)
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JP2005108306A (ja) * | 2003-09-29 | 2005-04-21 | Hoya Corp | 磁気ディスク用ガラス基板の化学強化処理方法、磁気ディスク用化学強化ガラス基板の製造方法及び磁気ディスクの製造方法 |
CN101356134B (zh) * | 2006-03-24 | 2011-12-07 | Hoya株式会社 | 磁盘用玻璃衬底的制造方法以及磁盘的制造方法 |
CN102473423B (zh) * | 2010-03-31 | 2016-03-30 | Hoya株式会社 | 磁盘用玻璃基板的制造方法 |
-
2012
- 2012-12-19 WO PCT/JP2012/082897 patent/WO2013099729A1/ja active Application Filing
- 2012-12-19 JP JP2013551647A patent/JP6105488B2/ja active Active
- 2012-12-19 CN CN201280062443.2A patent/CN104160444B/zh active Active
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2001098298A (ja) * | 1999-09-27 | 2001-04-10 | Hitachi Plant Eng & Constr Co Ltd | アルミノシリケートガラス基板又はセラミックガラス基板の洗浄液及び洗浄方法 |
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 |
JP2008043842A (ja) * | 2006-08-11 | 2008-02-28 | Kaijo Corp | 超音波洗浄装置 |
JP2008243342A (ja) * | 2007-03-29 | 2008-10-09 | Hoya Corp | 磁気ディスク用ガラス基板の超音波洗浄装置および超音波洗浄方法、磁気ディスク製造方法ならびに磁気ディスク |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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CN106269692A (zh) * | 2016-08-19 | 2017-01-04 | 湖北仁齐科技有限公司 | 一种cnc玻璃盖板的清洗方法 |
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CN104160444B (zh) | 2017-03-15 |
CN104160444A (zh) | 2014-11-19 |
JPWO2013099729A1 (ja) | 2015-05-07 |
JP6105488B2 (ja) | 2017-03-29 |
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