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WO2011021478A1 - Procédé de fabrication de substrat en verre, substrat en verre, procédé de fabrication de support d'enregistrement magnétique et support d'enregistrement magnétique - Google Patents

Procédé de fabrication de substrat en verre, substrat en verre, procédé de fabrication de support d'enregistrement magnétique et support d'enregistrement magnétique Download PDF

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Publication number
WO2011021478A1
WO2011021478A1 PCT/JP2010/062588 JP2010062588W WO2011021478A1 WO 2011021478 A1 WO2011021478 A1 WO 2011021478A1 JP 2010062588 W JP2010062588 W JP 2010062588W WO 2011021478 A1 WO2011021478 A1 WO 2011021478A1
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WIPO (PCT)
Prior art keywords
glass substrate
polishing
manufacturing
recording medium
magnetic recording
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Ceased
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PCT/JP2010/062588
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English (en)
Japanese (ja)
Inventor
慎一 佐伯
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Konica Minolta Opto Inc
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Konica Minolta Opto Inc
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Priority to JP2011527621A priority Critical patent/JPWO2011021478A1/ja
Publication of WO2011021478A1 publication Critical patent/WO2011021478A1/fr
Anticipated expiration legal-status Critical
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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
    • 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
    • B24B37/042—Lapping machines or devices; Accessories designed for working plane surfaces operating processes therefor
    • 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
    • C03C15/00—Surface treatment of glass, not in the form of fibres or filaments, by etching
    • C03C15/02—Surface treatment of glass, not in the form of fibres or filaments, by etching for making a smooth surface
    • 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
    • C03C19/00—Surface treatment of glass, not in the form of fibres or filaments, by mechanical means

Definitions

  • the present invention relates to a glass substrate manufacturing method, a glass substrate, a magnetic recording medium manufacturing method, and a magnetic recording medium.
  • Such a glass substrate such as a magnetic disk is manufactured by polishing the glass substrate called a blank material.
  • a glass substrate blade material
  • a method of manufacturing by press molding, a method of cutting and manufacturing a plate glass manufactured by a float method, and the like are known. If the glass substrate is cut into a certain shape, the surface has large irregularities, and it is necessary to polish the surface. Also, a technique for polishing with higher accuracy is required because of the demand for higher density.
  • the glass surface finishing process is performed in the order of a first polishing process and a second polishing process (see, for example, Patent Document 1 and Patent Document 2).
  • the first polishing process and the second polishing process are so-called polishing processes. After removing scratches and defects in the first polishing process to make the surface of the glass substrate have a predetermined surface roughness, Polish the surface more precisely.
  • a method of polishing using a polishing liquid containing an abrasive is used in both the first polishing step and the second polishing step.
  • the present invention has been made in view of the above problems, and a glass substrate manufacturing method capable of efficiently manufacturing a glass substrate having high smoothness, and a magnetic recording medium having high smoothness can be efficiently manufactured.
  • An object of the present invention is to provide a method for manufacturing a magnetic recording medium.
  • the present invention has the following features.
  • a method for producing a magnetic recording medium comprising a step of forming a magnetic film on a surface of a glass substrate produced using the method for producing a glass substrate according to 1 above.
  • the step of immersing in acid or alkali, the rinsing step, and the second polishing step are performed in this order, so that the substrate surface is hydrated before the second polishing step.
  • the processing stability of the entire surface of the substrate is improved.
  • the polishing liquid spreads uniformly over the entire surface of the glass substrate with improved processing stability polishing with high smoothness is possible in a short time.
  • FIG. 1 is a diagram showing an overall configuration of a glass substrate 1 according to the present invention.
  • the glass substrate 1 has a donut-shaped disk shape with a hole 5 formed in the center.
  • 10t is an outer peripheral end surface
  • 20t is an inner peripheral end surface
  • 7a is a front main surface
  • 7b is a back main surface.
  • FIG. 2 is a perspective view of a magnetic disk as an example of a magnetic recording medium according to the present invention.
  • the magnetic disk D has a magnetic film 2 directly formed on the surface of a circular glass substrate 1.
  • the magnetic film 2 can also be provided on the back main surface 7b.
  • FIG. 3 is a manufacturing process diagram of an example of a method for manufacturing a glass substrate according to the present invention.
  • the manufacturing process of the present embodiment is characterized in that after performing the first polishing process, before performing the second polishing process, an acid or alkali solution dipping process and a rinsing process are performed in this order.
  • the manufacturing process of the glass substrate of this embodiment is demonstrated in detail using FIG.
  • the glass substrate of the present invention is not limited to a magnetic recording medium, and can be used for a magneto-optical disk, an optical disk, and the like.
  • ⁇ Manufacturing process of glass substrate> There is no particular limitation on the size of the glass substrate. For example, there are glass substrates of various sizes such as an outer diameter of 2.5 inches, 1.8 inches, 1 inch, and 0.8 inches. Further, the thickness of the glass substrate is not limited, and there are glass substrates having various thicknesses such as 2 mm, 1 mm, and 0.63 mm.
  • Glass melting process First, the glass material is melted.
  • soda lime glass mainly composed of SiO 2 , Na 2 O, CaO
  • aluminosilicate glass and borosilicate glass are particularly preferable because they are excellent in impact resistance and vibration resistance.
  • the disc-shaped blank material may be manufactured by cutting a sheet glass formed by, for example, a downdraw method or a float method with a grinding stone, without using press molding.
  • the press-formed blank is drilled at the center with a core drill or the like having a diamond grindstone or the like at the cutter.
  • both surfaces of the glass substrate are lapped to preliminarily adjust the overall shape of the glass substrate, that is, the parallelism, flatness, and thickness of the glass substrate.
  • the inner and outer diameters are processed by grinding the outer peripheral end surface and the inner peripheral end surface of the glass substrate with a grinding wheel such as a drum-like diamond.
  • a grinding wheel such as a drum-like diamond.
  • the outer diameter and roundness of the glass substrate, the inner diameter of the hole, and the concentricity of the glass substrate and the hole are finely adjusted. For example, a 45 ° chamfer of about 0.1 mm to 0.2 mm is performed.
  • the order from the first lapping process after the coring process to the outer peripheral end face machining process is not limited to that shown in FIG. 3 and can be changed as appropriate according to the situation.
  • the lapping process may be performed first, and then the inner / outer diameter machining process, the inner circumference, and the outer circumference end face machining process may be performed.
  • a second lapping step, an inner circumference and an outer circumference end face machining step may be performed.
  • a polishing machine for lapping a glass substrate in the first and second lapping steps will be described.
  • the double-side polishing machine includes a disk-shaped upper surface plate and a lower surface plate that are arranged vertically so as to be parallel to each other, and rotate in opposite directions.
  • a plurality of diamond pellets for wrapping the main surface of the glass substrate are attached to the opposing surfaces of the upper and lower surface plates.
  • Between the upper and lower surface plates there are a plurality of carriers that rotate in combination with an internal gear provided in an annular shape on the outer periphery of the lower surface plate and a sun gear provided around the rotation axis of the lower surface plate.
  • the carrier is provided with a plurality of holes, and a glass substrate is fitted into the holes.
  • the upper and lower surface plates, the internal gear, and the sun gear can be operated by separate driving.
  • the lapping operation of the polishing machine is such that the upper and lower surface plates rotate in opposite directions, and the carrier sandwiched between the surface plates through the diamond pellets rotates with the surface plate holding a plurality of glass substrates. Revolves in the same direction as the lower surface plate relative to the center of rotation.
  • the glass substrate can be lapped by supplying the grinding liquid between the upper surface plate and the glass substrate, and the lower surface plate and the glass substrate.
  • the processing pressure of the surface plate applied to the glass substrate and the rotation speed of the surface plate are adjusted as appropriate according to the desired lapping state.
  • the processing pressure in the first and second lapping steps is preferably 5884 Pa to 11768 Pa.
  • the rotation speed of the surface plate is preferably about 5 to 30 rpm, and the rotation speed of the upper surface plate is preferably about 30 to 40% slower than the lower surface rotation speed. If the processing pressure by the surface plate is increased and the rotation speed of the surface plate is increased, the lapping amount increases. However, if the processing pressure is increased too much, the surface roughness will not be good, and if the rotation speed is too high, the flatness will be increased. Is not good. Further, when the processing pressure is small and the rotation speed of the surface plate is slow, the amount of lapping is small and the production efficiency is lowered.
  • the surface roughness of the main surface of the glass substrate is Rz (maximum height roughness) of 2 ⁇ m to 4 ⁇ m, Ra (arithmetic)
  • the average roughness is preferably about 0.2 ⁇ m to 0.4 ⁇ m.
  • the surface roughness at the time when the first lapping step is completed is preferably such that Rz is 4 ⁇ m to 8 ⁇ m and Ra is about 0.4 ⁇ m to 0.8 ⁇ m.
  • the inner and outer end faces of the glass substrate are polished by brushing in the inner and outer end face processing steps.
  • the brush is preferably made of nylon, polypropylene or the like having a diameter of about 0.2 to 0.3 mm.
  • the polishing liquid is preferably cerium oxide having a particle size of about several ⁇ m.
  • the surface roughness of the inner and outer end faces is preferably such that Rz is 0.2 ⁇ m to 0.4 ⁇ m and Ra is about 0.02 ⁇ m to 0.04 ⁇ m.
  • the shape of the end surface of the glass substrate that has undergone the inner and outer diameter processing steps and the inner and outer peripheral end surface processing steps is such that the corner formed by the main surface and the end surface is removed, and the position is about 0.2 mm to 0.5 mm from the outer peripheral end surface. From the main surface.
  • Ra absolute mean roughness
  • Rz maximum height roughness
  • the diamond pellet and the grinding liquid are used when polishing the glass substrate.
  • a polishing method by attaching a pad to the polishing surface of the upper and lower surface plates and supplying the polishing liquid.
  • the abrasive include cerium oxide, zirconium oxide, aluminum oxide, manganese oxide, colloidal silica, and diamond. These are dispersed in water and used as a slurry.
  • the pad is divided into a hard pad and a soft pad, but can be appropriately selected and used as necessary.
  • the hard pad include pads made of hard velor, urethane foam, pitch-containing suede, etc.
  • examples of the soft pad include pads made of suede, velor, etc.
  • the polishing method using a pad and an abrasive can correspond to rough polishing to precision polishing by changing the particle size of the abrasive and the type of pad. Therefore, in the first lapping step and the second lapping step, the abrasive, the particle size of the abrasive, and the pad are appropriately combined so that the above-mentioned surface roughness can be obtained by efficiently removing large undulations, chips, cracks, etc. Can respond.
  • polishing machines used in the first lapping process and the second lapping process have the same configuration, but it is preferable to perform polishing using different polishing machines prepared for each process. This is because the dedicated diamond pellets are pasted, so that the replacement is a large-scale operation, and complicated operations such as resetting the polishing conditions are required, resulting in a reduction in manufacturing efficiency.
  • the glass substrate is immersed in a chemical strengthening solution to form a chemically strengthened layer on the glass substrate.
  • a chemical strengthening solution By forming the chemical strengthening layer, impact resistance, vibration resistance, heat resistance and the like can be improved.
  • alkali metal ions such as lithium ions and sodium ions contained in the glass substrate are converted into alkali ions such as potassium ions having a larger ion radius. This is performed by the ion exchange method for substitution. Compressive stress is generated in the ion-exchanged region due to the distortion caused by the difference in ion radius, and the surface of the glass substrate is strengthened.
  • the chemical strengthening treatment liquid is not particularly limited, and a known chemical strengthening treatment liquid can be used. Usually, it is common to use a molten salt containing potassium ions or a molten salt containing potassium ions and sodium ions. Examples of the molten salt containing potassium ions and sodium ions include potassium and sodium nitrates, carbonates, sulfates, and mixed molten salts thereof. Among these, from the viewpoint that the melting point is low and deformation of the glass substrate can be prevented, it is preferable to use nitrate.
  • the chemical strengthening solution is heated to a temperature higher than the temperature at which the above components melt.
  • the heating temperature of the chemical strengthening treatment liquid is preferably lower than the glass transition point (Tg) of the glass substrate, more preferably lower than the glass transition point ⁇ 50 ° C.
  • the glass substrate is placed in a preheating tank prior to immersion in the chemical strengthening treatment liquid. You may have the preheating process heated to predetermined temperature.
  • the thickness of the chemically strengthened layer is preferably in the range of about 5 ⁇ m to 15 ⁇ m in view of improving the strength of the glass substrate and shortening the polishing process time.
  • the thickness of the reinforcing layer is within this range, a glass substrate having good impact resistance, which is flatness and mechanical strength, can be obtained.
  • the shape of the outer peripheral edge of the front main surface 7a after the chemical strengthening process is almost the same as that before the chemical strengthening process, and the above-mentioned chemical strengthening layer of about 5 ⁇ m to 15 ⁇ m is almost uniformly placed on the entire surface of the glass substrate. It becomes.
  • polishing process Next, the polishing process will be described.
  • the surface of the glass substrate is precisely finished, and the shape of the outer peripheral end of the main surface is polished to a desired shape.
  • polishing can be done.
  • the polishing method uses a polishing machine having the same configuration as the polishing machine used in the first and second lapping processes, except that a pad and a polishing liquid are used instead of the diamond pellets and the grinding liquid used in the lapping process. .
  • the pad is a hard pad having a hardness A of about 80 to 90, and it is preferable to use, for example, urethane foam.
  • the abrasive is preferably used in the form of a slurry by dispersing cerium oxide, colloidal silica, zirconium oxide, titanium oxide, manganese oxide or the like having a particle size of 0.6 ⁇ m to 2.5 ⁇ m in water.
  • the mixing ratio of water and abrasive is preferably about 1: 1 to 4: 1.
  • the processing pressure on the glass substrate by the surface plate is preferably 8826 Pa to 10787 Pa.
  • the processing pressure applied to the glass substrate by the surface plate greatly affects the shape of the outer peripheral edge. As the processing pressure is increased, the inner side of the outer peripheral end tends to decrease and increase toward the outer side. Further, when the processing pressure is reduced, the outer peripheral end portion tends to be close to a flat surface and the surface sagging increases. The processing pressure can be determined while observing such a tendency.
  • the rotation speed of the surface plate is changed from 20 rpm to 60 rpm so that the flatness obtained until the chemical strengthening process is maintained and the surface roughness is further improved, and the rotation speed of the upper surface plate is set from the lower surface plate rotation speed. It is preferable to slow by 30% to 40%.
  • the polishing amount is preferably 30 ⁇ m to 40 ⁇ m according to the above polishing conditions. If it is less than 30 ⁇ m, scratches and defects cannot be removed sufficiently. If it exceeds 40 ⁇ m, the surface roughness can be in the range of Rz from 0.2 nm to 30 nm and Ra from 0.5 nm to 2 nm. However, polishing is performed more than necessary, and the production efficiency decreases.
  • a modification treatment is performed in which the glass substrate is immersed in an acid or alkali solution to remove a hydrated layer or a work-affected layer on the surface of the glass substrate.
  • the entire surface of the glass substrate can be uniformly and stably polished in the second polishing step.
  • the acid or alkali used in this step is not particularly limited, and for example, an acid such as HF or H 2 SO 4 or an alkaline solution such as NaOH or KOH can be used.
  • the temperature of the acid or alkali solution is preferably 20 ° C. to 40 ° C., and the immersion time is preferably in the range of 60 sec to 300 sec.
  • the glass substrate is immersed in pure water or the like to remove the acid or alkali solution attached to the glass substrate.
  • the second polishing step is a step of polishing the surface of the glass substrate after the first polishing step more precisely.
  • the pad used in the second polishing step is a soft pad having a hardness of about 65 to 80 (Asker-C) that is softer than the pad used in the first polishing step.
  • Asker-C urethane foam or suede is preferably used.
  • As the abrasive cerium oxide, colloidal silica, zirconium oxide, titanium oxide, manganese oxide, and the like similar to those in the first polishing step can be used. However, in order to make the surface of the glass substrate smoother, the particle size is finer. It is preferable to use an abrasive with little variation.
  • An abrasive having an average particle size of 10 nm to 100 nm is dispersed in water to form a slurry and used as a polishing liquid.
  • the mixing ratio of water and abrasive is preferably about 3: 1 to 20: 1.
  • the glass substrate before the second polishing step, the glass substrate is immersed in an acid or alkali solution to remove the hydrated layer or the work-affected layer on the surface of the glass substrate. Compared to immediately after the first polishing step, it is greatly improved.
  • the polishing liquid spreads uniformly on the surface of the glass substrate, and uniform polishing characteristics are obtained over the entire surface of the glass substrate.
  • the processing pressure on the glass substrate by the surface plate is preferably 8826 Pa to 10787 Pa.
  • the processing pressure applied to the glass substrate by the surface plate greatly affects the shape of the outer peripheral edge as in the first polishing step, but the shape cannot be changed as efficiently as the first polishing step because the polishing rate is slow.
  • the change in the shape of the outer peripheral end due to the adjustment of the processing pressure is the same as in the first polishing step, and when the processing pressure is increased, the inner side of the outer peripheral end tends to decrease and increase toward the outside. Further, when the processing pressure is reduced, the outer peripheral end portion tends to be close to a flat surface and the surface sagging increases. In order to obtain the shape of the outer peripheral end, the processing pressure can be determined while observing such a tendency.
  • the rotation speed of the surface plate is preferably 5 to 50 rpm, and the rotation speed of the upper surface plate is preferably 30% to 40% slower than the rotation speed of the lower surface plate.
  • the polishing conditions in the second polishing step are adjusted to obtain a desired shape of the outer peripheral edge, and the surface roughness Ra can be 0.15 nm or less.
  • the polishing amount is preferably 2 ⁇ m to 5 ⁇ m. When the polishing amount is within this range, minute defects such as minute roughness and undulation generated on the surface and minute scratches generated in the process so far can be efficiently removed.
  • the manufacturing method of the glass substrate for information recording media you may have various processes other than the above. For example, an annealing process for relaxing internal strain of the glass substrate, a heat shock process for confirming the reliability of the strength of the glass substrate, various inspection / evaluation processes, and the like may be included.
  • the polishing machine used in the first polishing process it is preferable not to use the polishing machine used in the first polishing process as it is, but to polish using another polishing machine that has the same configuration but is prepared for each process. . This is because, if the polishing machine used in the first polishing step is used as it is, the polishing accuracy in the second polishing step decreases due to the abrasive remaining in the first polishing step, and the polishing conditions are reset. This is because work is required and the production efficiency is lowered.
  • a conventionally known method can be used as a method for forming the magnetic film 2.
  • a method in which a thermosetting resin in which magnetic particles are dispersed is spin-coated on a substrate, or a method in which sputtering or electroless plating is used. The method of doing is mentioned.
  • the film thickness by spin coating is about 0.3 ⁇ m to 1.2 ⁇ m
  • the film thickness by sputtering is about 0.04 ⁇ m to 0.08 ⁇ m
  • the film thickness by electroless plating is 0.05 ⁇ m to 0.1 ⁇ m. From the viewpoint of thinning and densification, film formation by sputtering and electroless plating is preferable.
  • the magnetic material used for the magnetic film is not particularly limited, and a conventionally known material can be used. However, in order to obtain a high coercive force, Ni having a high crystal anisotropy is basically used, and Ni or A Co-based alloy to which Cr is added is suitable. Specific examples include CoPt, CoCr, CoNi, CoNiCr, CoCrTa, CoPtCr, and CoNiPt containing Co as a main component, CoNiCrPt, CoNiCrTa, CoCrPtTa, CoCrPtB, and CoCrPtSiO.
  • the magnetic film may have a multilayer structure (for example, CoPtCr / CrMo / CoPtCr, CoCrPtTa / CrMo / CoCrPtTa) that is divided by a nonmagnetic film (for example, Cr, CrMo, CrV, etc.) to reduce noise.
  • a nonmagnetic film for example, Cr, CrMo, CrV, etc.
  • granular materials such as ferrite, iron-rare earth, and non-magnetic films made of SiO 2 , BN, etc. are dispersed with magnetic particles such as Fe, Co, FeCo, CoNiPt, etc. Also good.
  • the magnetic film may be of any recording type of inner surface type and vertical type.
  • a lubricant may be thinly coated on the surface of the magnetic film in order to improve the sliding of the magnetic head.
  • the 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.
  • the underlayer in the magnetic disk 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.
  • Cr alone or a Cr alloy is preferable from the viewpoint of improving magnetic characteristics.
  • 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 that prevents wear and corrosion of the magnetic film 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 formed continuously with an in-line type sputtering apparatus, such as an underlayer and a magnetic film.
  • these protective layers may be a single layer, or may have a multilayer structure including the same or different layers. Note that another protective layer may be formed on the protective layer or instead of the protective layer.
  • tetraalkoxysilane is diluted with an alcohol solvent on the Cr layer, and then colloidal silica fine particles are dispersed and applied, and then baked to form a silicon dioxide (SiO 2 ) layer. It may be formed.
  • Example 10 The glass substrates of Examples 1 to 12 were produced as follows.
  • Aluminosilicate glass (Tg: 500 ° C.) was used as a glass material, and 1200 pieces of blank materials were produced by press molding the molten glass.
  • Example 1 (Acid or alkaline solution dipping process)
  • glass substrates were immersed in 25 ° C. solutions of HF having different concentrations for 120 seconds.
  • the concentration of the HF solution was 0.1% by mass in Example 1, 0.3% by mass in Example 2, 0.5% by mass in Example 3, 1.0% by mass in Example 4, and Example 5 Then, it was 1.5 mass%.
  • each glass substrate was immersed in a solution of NaOH having a different concentration at 25 ° C. for 120 seconds.
  • the concentration of the NaOH solution was 0.1% by weight in Example 6, 0.3% by weight in Example 7, 0.5% by weight in Example 8, 1.0% by weight in Example 9, and Example 10 Was 2.0 mass%, Example 11 was 3.0 mass%, and Example 12 was 5.0 mass%.
  • polishing step A suede pad manufactured by FILWEL was used, and cerium oxide and colloidal silica were used as the abrasive.
  • the polishing conditions were pad hardness 80 (Asker-C), abrasive particle size 30 (nm), rotation speed 30 (rpm), and processing pressure 10787 (Pa).
  • the polishing rate was determined from the polishing amount when the glass substrates of Examples 1 to 12 were polished for a predetermined time. Next, polishing was performed by obtaining a processing time for the polishing amount to be a target of 2 ⁇ m from the polishing rates of Examples 1 to 12.
  • the target polishing amount of the comparative example is also 2 ⁇ m.
  • the processing time was set to 33.4 minutes from the polishing rate under the conditions of the comparative example obtained by conducting an experiment in advance.
  • the temperature conditions and the like in each step are the same as those in Example 1.
  • 100 glass substrates were produced.
  • the polishing rate was obtained from the polishing amount when the glass substrate was polished for a predetermined time in the second polishing step.
  • the surface roughness Ra was measured using an atomic force microscope (AFM) based on JIS B0601: 2001.
  • the number of surface defects was determined by irradiating the surface of the glass substrate with laser using OSA (Optical Surface Analyzer) and detecting the surface defects from scattering.
  • the detection sensitivity was set to 0.08 ⁇ m, and the number of defects having a size of 0.1 ⁇ m or more on the substrate surface was evaluated.
  • Waviness Wa was measured using a multi-function disk interferometer (Optiflat Phase Shift Technology Inc.), and the entire surface of the glass substrate was measured.
  • the measurement principle is a method of measuring a subtle shape change of the surface by irradiating the surface of the glass substrate with white light and measuring an intensity change of interference between the reference light and the measurement light having different phases.
  • the obtained measurement data was cut off with a period of 5 mm or more to obtain a waviness Wa.
  • Table 1 shows the average values of the measurement results obtained by measuring the polishing rate, surface roughness, waviness Wa and the number of surface defects on the surface of each of the 100 glass substrates prepared in Examples 1 to 12.
  • the polishing rate is described as a ratio with the polishing rate of the comparative example being 0.06 ⁇ m / min as 1.
  • Table 2 shows the average values of the measurement results obtained by measuring the polishing rate, surface roughness, waviness Wa and the number of surface defects on the surface of each of 100 glass substrates prepared in Comparative Examples.
  • the polishing rate of the comparative example is 0.06 ⁇ m / min.
  • polishing rates of Examples 1 to 12 are all higher than the polishing rate of the comparative example, and each example can shorten the processing time of the second polishing step compared to the comparative example.
  • Example 1 the number of surface defects was smaller than that of the comparative example. Further, in Examples 1 and 2, the waviness Wa and the surface roughness Ra are both smaller than the waviness Wa and the surface roughness Ra of the comparative example, and can be processed into a surface state having higher smoothness than the comparative example.
  • the waviness Wa is in the range of 0.32 nm to 0.38 nm
  • the surface roughness Ra is in the range of 0.12 nm to 0.14 nm
  • the waviness Wa of the comparative example is 0.36 nm.
  • the roughness Ra was approximately equivalent to 0.12 nm.
  • a glass substrate manufacturing method capable of efficiently manufacturing a glass substrate having high smoothness, and a magnetism capable of efficiently manufacturing a magnetic recording medium having high smoothness.
  • a method for manufacturing a recording medium can be provided.

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Abstract

L'invention porte sur un procédé de fabrication d'un substrat en verre, qui a une étape d'immersion de substrat en verre dans une solution acide ou alcaline, et une étape de rinçage dans laquelle le substrat en verre, qui a été soumis à l'étape d'immersion, est nettoyé. Dans le procédé, après réalisation d'une première étape de polissage, l'étape d'immersion, l'étape de rinçage, et une seconde étape de polissage sont réalisées dans cet ordre. Ainsi, le substrat en verre ayant un poli élevé peut être fabriqué de manière efficace.
PCT/JP2010/062588 2009-08-17 2010-07-27 Procédé de fabrication de substrat en verre, substrat en verre, procédé de fabrication de support d'enregistrement magnétique et support d'enregistrement magnétique Ceased WO2011021478A1 (fr)

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JP2012218995A (ja) * 2011-04-12 2012-11-12 Asahi Glass Co Ltd 強化ガラス板及びカバーガラスの製造方法並びにカバーガラス
WO2016129164A1 (fr) * 2015-02-13 2016-08-18 日本電気硝子株式会社 Article en verre et son procédé de fabrication
JP2019012183A (ja) * 2017-06-30 2019-01-24 クアーズテック株式会社 フォトマスク用基板及びその製造方法

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JP2000348338A (ja) * 1999-03-30 2000-12-15 Hoya Corp 情報記録媒体用ガラス基板の製造方法、及び情報記録媒体の製造方法
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JP2012218995A (ja) * 2011-04-12 2012-11-12 Asahi Glass Co Ltd 強化ガラス板及びカバーガラスの製造方法並びにカバーガラス
WO2016129164A1 (fr) * 2015-02-13 2016-08-18 日本電気硝子株式会社 Article en verre et son procédé de fabrication
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JP2019012183A (ja) * 2017-06-30 2019-01-24 クアーズテック株式会社 フォトマスク用基板及びその製造方法

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