WO2012132073A1 - Procédé de fabrication d'un substrat de verre pour support d'enregistrement d'informations et support d'enregistrement d'informations - Google Patents

Procédé de fabrication d'un substrat de verre pour support d'enregistrement d'informations et support d'enregistrement d'informations Download PDF

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Publication number
WO2012132073A1
WO2012132073A1 PCT/JP2011/072949 JP2011072949W WO2012132073A1 WO 2012132073 A1 WO2012132073 A1 WO 2012132073A1 JP 2011072949 W JP2011072949 W JP 2011072949W WO 2012132073 A1 WO2012132073 A1 WO 2012132073A1
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glass substrate
polishing
information recording
recording medium
processing
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PCT/JP2011/072949
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English (en)
Japanese (ja)
Inventor
隆史 小松
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コニカミノルタアドバンストレイヤー株式会社
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Priority to JP2013507042A priority Critical patent/JPWO2012132073A1/ja
Publication of WO2012132073A1 publication Critical patent/WO2012132073A1/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 in particular, includes a method for manufacturing a glass substrate for information recording medium used for manufacturing an information recording medium, and the glass substrate for information recording medium.
  • the present invention relates to an information recording medium.
  • An information recording medium such as a magnetic disk is mounted as a hard disk on a computer or the like.
  • An information recording medium is manufactured by forming a magnetic thin film layer including a recording layer using properties such as magnetism, light, or magnetomagnetism on the surface of a substrate. As the recording layer is magnetized by the magnetic head, predetermined information is recorded on the information recording medium.
  • the recording density of information recording media is improving year by year. Accordingly, high quality is required for the quality of substrates used for information recording media.
  • an aluminum substrate has been used as a substrate for an information recording medium.
  • the recording density is improved, it is gradually being replaced by a glass substrate that is superior in smoothness and strength of the substrate surface as compared with an aluminum substrate.
  • the method for producing a glass substrate for an information recording medium has a polishing step for ensuring high surface shape accuracy.
  • a polishing step for ensuring high surface shape accuracy.
  • two or more stages of polishing processes in which slurry and polishing pads having different processing capabilities are effectively combined are applied.
  • Conventional techniques for polishing a glass substrate have been proposed in, for example, Japanese Unexamined Patent Application Publication No. 2009-154232 (Patent Document 1) and Japanese Unexamined Patent Application Publication No. 2008-142851 (Patent Document 2).
  • Patent Document 1 In the technique described in Japanese Patent Application Laid-Open No. 2009-154232 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2008-142851 (Patent Document 2), impurities such as agglomerated slurry are washed by cleaning the surface of the polishing pad used in the polishing process. Can be removed periodically from the surface of the polishing pad to prevent accumulation of impurities on the surface of the polishing pad.
  • the present invention has been made in view of the above problems, and its main purpose is to suppress the accumulation of impurities on the end face of the processing tool, and to reduce the generation of scratches and deposits on the main surface of the glass substrate. It is to provide a method for producing a glass substrate for an information recording medium.
  • the method for producing a glass substrate for information recording medium is a method for producing a glass substrate for information recording medium in which a magnetic recording layer is formed on the main surface of the glass substrate, the step of forming the glass substrate, The processing surface of a processing tool having a flat processing surface for grinding or polishing the surface and an end surface forming the periphery of the processing surface is brought into contact with the main surface, and the processing tool is slid relative to the main surface. And processing the main surface.
  • the end face is inclined at an angle greater than 90 ° with respect to the work surface.
  • the end face may form an angle of 95 ° to 170 ° with respect to the processed surface.
  • a part of the main surface may protrude from the processing surface.
  • the processing step may be a final polishing step of the main surface.
  • the processing surface and end surface of the processing tool may be cleaned after processing the main surface of the glass substrate once or a plurality of times.
  • An information recording medium includes a glass substrate obtained by any one of the above-described methods for producing a glass substrate for an information recording medium, and a magnetic recording layer formed on the surface of the glass substrate.
  • impurities such as agglomerated slurry can be prevented from accumulating on the end surface of the processing tool, and the generation of scratches and deposits on the main surface of the glass substrate can be reduced. Therefore, the yield of the glass substrate can be improved.
  • 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 circular disk-shaped 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 not particularly limited, and is, for example, 0.8 inch, 1.0 inch, 1.8 inch, 2.5 inch, or 3.5 inch outer diameter.
  • the thickness of the glass substrate is, for example, 0.30 to 2.2 mm from the viewpoint of preventing breakage.
  • the glass substrate has an outer diameter of about 65 mm, an inner diameter of about 20 mm, and a thickness of about 0.8 mm.
  • the thickness of the glass substrate 1 is a value calculated by averaging the values measured at a plurality of arbitrary points that are point targets on the glass substrate 1.
  • the magnetic disk 10 is configured by forming a magnetic film on the front main surface 1A of the glass substrate 1 and forming a magnetic thin film layer 2 including a magnetic recording layer.
  • 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 on the front main surface 1A of the glass substrate 1 by a sputtering method, an electroless plating method, or the like.
  • 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, 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. 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.
  • a tetraalkoxysilane 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 1 in the embodiment.
  • the glass substrate manufacturing method in the present embodiment includes a glass blank material preparation step (step S10), a glass substrate formation step (step S20), a polishing step (step S30), a chemical strengthening step (step S40), and a cleaning step ( Step S50).
  • a 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 S40).
  • 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).
  • general aluminosilicate glass is used as the glass material.
  • the aluminosilicate glass is composed of 58 mass% to 75 mass% SiO 2 , 5 mass% to 23 mass% Al 2 O 3 , 3 mass% to 10 mass% Li 2 O, and 4 mass% to 13 mass. % Na 2 O as a main component.
  • 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 sheet glass (sheet glass) formed by a downdraw method or a float method with a grinding wheel. Further, the glass material is not limited to aluminosilicate glass, and may be any material.
  • step S20 a lapping process is performed on both main surfaces of the press-molded glass blank material for the purpose of improving dimensional accuracy and shape accuracy (step).
  • 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 process is performed using a double-sided lapping device using a planetary gear mechanism. Specifically, the lap surface plate is pressed from above and below both main surfaces of the glass blank material, the grinding liquid is supplied onto both main surfaces, the glass blank material and the lap surface plate are moved relative to each other, and the lap surface is moved. A polishing process is performed. By the lapping process, the approximate parallelism, flatness, thickness, and the like of the glass substrate are preliminarily adjusted, and a glass base material having an approximately flat main surface is obtained.
  • the surface accuracy of both surfaces of the glass substrate is 0 ⁇ m to 1 ⁇ m, You may finish to about 6 micrometers in surface roughness Rmax.
  • 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 polishing process (step S31) (step S33).
  • a double-side polishing device using a planetary gear mechanism is used.
  • polishing is performed using a polishing pad such as hard velor, urethane foam, or pitch-impregnated suede.
  • abrasive general cerium oxide abrasive grains are used.
  • the glass substrate is subjected to polishing again, and minute defects and the like 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. For example, polishing is performed using a polishing pad which is a soft polisher made of suede or velor.
  • the polishing agent general colloidal silica finer than the cerium oxide used in the first polishing step is used.
  • FIG. 4 is a partial perspective view of a double-side polishing apparatus 1000 used in the polishing process
  • FIG. 5 is a partial cross-sectional view of the polishing pads 310 and 410.
  • a double-side polishing apparatus 1000 includes an upper surface plate (upper whetstone holding surface plate) 300, a lower surface plate (lower whetstone holding surface plate) 400, and a lower surface plate 400 of the upper surface plate 300.
  • the polishing pads 310 and 410 are an example of a processing tool for polishing both main surfaces of the glass substrate 1.
  • the upper surface plate 300 and the lower surface plate 400 rotate in directions opposite to each other with respect to the revolution direction of the carrier 500.
  • Carrier 500 is arranged in a gap formed between upper surface plate 300 and lower surface plate 400.
  • the disk-shaped glass substrate 1 is held by this carrier 500.
  • FIG. 4 a lower surface plate 400 that is one surface plate among the upper surface plate 300 and the lower surface plate 400 that is a pair of surface plates that sandwich the plurality of glass substrates 1 held by the carrier 500 is illustrated.
  • the upper surface plate 300 is not shown.
  • FIG. 5 the carrier 500 and the glass substrate 1 held by the carrier 500 are not shown.
  • the polishing pad 310 has a processed surface 311 that contacts the front main surface 1 ⁇ / b> A of the glass substrate 1.
  • the processing surface 311 is one surface of the annular pad-shaped polishing pad 310.
  • the processing surface 311 extends in a planar manner, and the planar shape is formed in an annular shape. With the processed surface 311 in contact with the front main surface 1A of the glass substrate 1, the front main surface 1A is polished by sliding the polishing pad 310 relative to the front main surface 1A.
  • An end surface 312 is provided on the periphery of the processing surface 311.
  • the planar shape of the boundary 313 between the processed surface 311 and the end surface 312 is circular.
  • the end surface 312 is formed in a conical surface shape.
  • the end surface 312 is provided so as to be inclined with respect to the processing surface 311 so as to form an angle ⁇ with the processing surface 311.
  • the polishing pad 410 has a processed surface 411 that contacts the back main surface 1B of the glass substrate 1.
  • the processing surface 411 is one surface of an annular plate-shaped polishing pad 410.
  • the processing surface 411 extends in a planar manner, and the planar shape is formed in an annular shape. With the processed surface 411 in contact with the back main surface 1B of the glass substrate 1, the back main surface 1B is polished by sliding the polishing pad 410 relative to the back main surface 1B.
  • An end face 412 is provided on the periphery of the processing surface 411.
  • the planar shape of the boundary 413 between the processed surface 411 and the end surface 412 is circular.
  • the end surface 412 is formed in a conical surface shape.
  • the end surface 412 is provided to be inclined with respect to the processing surface 411 so as to form an angle ⁇ with the processing surface 411.
  • the upper surface plate 300, the lower surface plate 400, and the polishing pads 310, 410 along the line passing through the center of the circle of the upper surface plate 300, the lower surface plate 400, and the polishing pads 310, 410 having an annular plate shape.
  • the cross section of is shown.
  • the processed surface 311 and the end surface 312 form an angle ⁇ .
  • the processed surface 411 and the end surface 412 form an angle ⁇ .
  • the angle ⁇ and the angle ⁇ may be equal to each other, or may be different from each other.
  • the angle ⁇ between the processed surface 311 and the end surface 312 and the angle ⁇ between the processed surface 411 and the end surface 412 are larger than 90 °.
  • the end faces 312 and 412 are inclined at an angle larger than 90 ° with respect to the processed surfaces 311 and 411.
  • the angles ⁇ and ⁇ each have an angle of 95 ° to 170 °.
  • the end surface 312 of the polishing pad 310 forms an angle of 95 ° or more and 170 ° or less with respect to the processing surface 311.
  • the end surface 412 of the polishing pad 410 forms an angle of 95 ° or more and 170 ° or less with respect to the processing surface 411.
  • the range of the angle ⁇ is defined as an average value of the angle formed by the processed surface 311 and the end surface 312 in the radial cross section of the annular plate-shaped polishing pad 310 over the entire circumference of the circle.
  • the range of the angle ⁇ is defined as an average value of the angle formed by the processing surface 411 and the end surface 412 in the radial cross section of the annular pad-shaped polishing pad 410 over the entire circumference of the circle. That is, if the angles ⁇ and ⁇ are the average in one circle of the polishing pads 310 and 410 within the above range, the angles ⁇ and ⁇ are outside the above range in one cross section along the radial direction of the polishing pads 310 and 410. It doesn't matter.
  • the surfaces of the polishing pads 310 and 410 may be cleaned.
  • the surface of the polishing pads 310 and 410 is cleaned by a carrier brush having hairs extending in a direction substantially perpendicular to the processing surfaces 311 and 411 or a high pressure supplied in a direction substantially perpendicular to the processing surfaces 311 and 411. It may be performed using water.
  • a carrier brush having hairs extending in a direction substantially perpendicular to the processing surfaces 311 and 411 or a high pressure supplied in a direction substantially perpendicular to the processing surfaces 311 and 411. It may be performed using water.
  • processing waste, aggregated abrasive grains, etc. existing on the surfaces of the polishing pads 310 and 410 or in the polishing pads 310 and 410 in the vicinity of the surfaces, etc. Can be removed to some extent.
  • the high-pressure water may be supplied in a direction inclined with respect to the processing surfaces 311 and 411.
  • the cleaning of the surfaces of the polishing pads 310 and 410 may be performed in any step in the polishing step (step S30), may be performed in any step in the polishing step (step S30), or You may perform after completion
  • the surfaces of the polishing pads 310 and 410 may be cleaned in the double-side polishing apparatus 1000.
  • the surfaces of the polishing pads 310 and 410 (that is, the processing surfaces 311 and 411 and the end surfaces 312 and 412) may be periodically cleaned every time one or a plurality of polishings are performed, or may be cleaned irregularly. May be.
  • the chemical strengthening layer is formed on both main surfaces of the glass substrate by immersing the glass substrate in the chemical strengthening treatment liquid (step S40).
  • a chemical strengthening treatment solution such as a solution for mixing potassium nitrate (70%) and sodium nitrate (30%) heated to 300 ° C. for 30 minutes, Perform chemical strengthening.
  • 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.
  • a chemically strengthened layer may be formed in a range from the glass substrate surface to about 5 ⁇ m to improve the rigidity of the glass substrate. 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.
  • a chemical strengthening step may be performed between the first polishing step (rough polishing) and the second polishing step (precision polishing).
  • the glass substrate is cleaned (step S50).
  • the deposits attached to both main surfaces of the glass substrate are removed.
  • the number of deposits on the glass substrate surface is inspected using an optical defect inspection apparatus or the like.
  • the magnetic thin film layer 2 is formed by forming a magnetic film on both main surfaces (or one of the main surfaces) of the glass substrate (corresponding to the glass substrate 1 shown in FIG. 1) that has been subjected to the chemical strengthening treatment. Is done.
  • 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.
  • FIG. 6 to 9 are diagrams showing relative movement of the glass substrate 1 with respect to the polishing pads 310 and 410 when the glass substrate 1 is polished using the double-side polishing apparatus 1000.
  • FIG. When polishing the glass substrate 1, the upper surface plate 300 and the lower surface plate 400 rotate in opposite directions. For example, when viewed from above the double-side polishing apparatus 1000, the upper surface plate 300 rotates clockwise and the lower surface plate 400 rotates counterclockwise. At this time, the carrier 500 revolves while rotating. For example, the carrier 500 rotates around the circular center formed by the carrier 500 itself while revolving clockwise or counterclockwise around the rotation axis of the upper surface plate 300 and the lower surface plate 400.
  • the relative position of the glass substrate 1 held by the carrier 500 with respect to the polishing pads 310 and 410 changes. Specifically, the glass substrate 1 moves in the radial direction of the polishing pads 310 and 410 from the state in which the entire glass substrate 1 is sandwiched between the polishing pads 310 and 410 shown in FIG. Thus, as shown in FIG. 7, a part of the glass substrate 1 passes outside the polishing pads 310 and 410.
  • a part of the front main surface 1 ⁇ / b> A of the glass substrate 1 is disposed outside the processing surface 311 of the polishing pad 310, and a part of the back main surface 1 ⁇ / b> B of the glass substrate 1 is the polishing pad 410.
  • the front main surface 1A and the back main surface 1B of the glass substrate 1 pass outside the processed surfaces 311 and 411.
  • the glass substrate 1 is subjected to a so-called “overhang rotation” in which at least a part of the glass substrate 1 extends beyond the periphery of the upper surface plate 300 and the lower surface plate 400 to the outside and passes outside the upper surface plate 300 and the lower surface plate 400.
  • a part of the front main surface 1A of the glass substrate 1 protrudes from the processing surface 311 of the polishing pad 310, and a part of the back main surface 1B protrudes from the processing surface 411 of the polishing pad 410.
  • FIG. 10 is a plan view schematically showing a state in which a part of the glass substrate 1 protrudes from the processing surface 311 of the polishing pad 310.
  • FIG. 10 shows a state in which the glass substrate 1 protrudes most from the upper surface plate 300 and the lower surface plate 400 during the polishing of the glass substrate 1.
  • the distance H between the boundary 313 between the processing surface 311 and the end surface 312 of the polishing pad 310 and the outer peripheral portion of the glass substrate 1 is the maximum length that the glass substrate 1 protrudes from the surface plate during polishing processing. And is called the overhang length.
  • an abrasive is supplied to polish the glass substrate 1.
  • slurry 600 containing abrasive grains is used as the abrasive.
  • the slurry 600 supplied to the space between the polishing pads 310 and 410 becomes the end surface of the glass substrate 1 as shown in FIGS. Or it is pushed out of the space by the end face of the carrier 500 and then returned to the space again.
  • the slurry 600 contains impurities 601 such as agglomerated slurry.
  • impurities 601 such as agglomerated slurry.
  • the impurity 601 exists in the space between the polishing pads 310 and 410.
  • the glass substrate 1 moves in the radial direction of the polishing pads 310 and 410 as the carrier 500 rotates, the impurities 601 are also pushed out of the space by the end surface of the glass substrate 1 (FIG. 7).
  • the processing surface 311 and the end surface 312 have an angle greater than 90 °, more specifically, 95 ° to 170 °. Has an angle ⁇ . Therefore, the end surface 312 is inclined with respect to the processing surface 311.
  • the processed surface 411 and the end surface 412 have an angle greater than 90 °, more specifically, an angle ⁇ of 95 ° to 170 °. Therefore, the end surface 412 is inclined with respect to the processing surface 411. Therefore, the impurity 601 pushed out of the space between the polishing pads 310 and 410 as shown in FIG. 7 travels along the end surfaces 312 and 412 as shown in FIGS. You can return to the space between.
  • impurities 601 such as agglomerated slurry are polished when the glass substrate 1 is exposed to the outside of the surface plate and then reenters the surface plate. It is wiped by the end face of the pad and left on the end face. Therefore, impurities accumulate on the end surface of the polishing pad.
  • the accumulated impurities 601 are dried on the end face, the surface of the overhanging glass substrate 1 is scratched by the impurities 601 and causes the surface of the glass substrate 1 to be scratched.
  • the impurity 601 having a high viscosity due to a decrease in moisture adheres to the surface of the glass substrate 1, causing a protrusion to be formed on the surface of the glass substrate 1.
  • the glass substrate 1 is regarded as a defective product, and the final yield of the glass substrate 1 is reduced.
  • the end faces 312 and 412 of the polishing pads 310 and 410 are not perpendicular to the processing surfaces 311 and 411, and the end faces 312 and 412 are inclined.
  • the impurities 601 are again drawn into the space between the polishing pads 310 and 410.
  • the structure is easy. This suppresses the impurities 601 from being wiped by the end faces 312 and 412 when the glass substrate 1 rotates in an overhanging manner in the polishing process, and the impurities 601 remaining on the end faces 312 and 412. Therefore, accumulation of impurities 601 such as agglomerated slurry contained in the slurry 600 on the end surfaces 312 and 412 of the polishing pads 310 and 410 can be suppressed.
  • the angle ⁇ between the processing surface 311 and the end surface 312 of the polishing pad 310 and the angle ⁇ between the processing surface 411 and the end surface 412 of the polishing pad 410 are less than 95 °, impurities 601 such as agglomerated slurry are end surfaces. Since it is easy to accumulate in 312 and 412, the angle is preferably set to 95 ° or more. Further, if the angle ⁇ and the angle ⁇ are larger than 170 °, the area of the processing surfaces 311 and 411 used for polishing among the surfaces of the polishing pads 310 and 410 is reduced and the polishing efficiency is lowered. It is preferable to do this. More preferably, the angle ⁇ and the angle ⁇ are 110 ° or more and 150 ° or less as an average of one round of the polishing pads 310 and 410.
  • the polishing pads 310 and 410 formed in advance in a predetermined shape are attached to the upper surface plate 300 and the lower surface plate 400, respectively. May be formed.
  • the double-side polishing apparatus 1000 attaches a polishing pad material covering the entire surface of the upper surface plate 300 and the lower surface plate 400 to the upper surface plate 300 and the lower surface plate 400, respectively, and cuts the periphery of the polishing pad material into a predetermined shape. By doing so, it may be formed.
  • the impurities 601 are easily drawn into the polishing pads 310 and 410 from the end surfaces 312 and 412, and are not accumulated on the end surfaces 312 and 412. Accordingly, the above-described effect of improving the flatness of the substrate can be obtained, the accumulation of the impurities 601 on the end faces 312 and 412 can be suppressed, and the yield of the glass substrate 1 can be improved.
  • the surface of the polishing pads 310 and 410 may be cleaned using a carrier brush having resin bristles such as nylon or high-pressure water having a pressure of about 7 MPa in the polishing process of the glass substrate 1. Since the end surfaces 312 and 412 of the polishing pads 310 and 410 are inclined with respect to the processing surfaces 311 and 411, even if the impurities 601 remain on the end surfaces 312 and 412 during the polishing process, a carrier brush or high-pressure water is not washed. The impurities 601 are removed from the end faces 312 and 412 in contact with the end faces 312 and 412. Therefore, accumulation of the impurities 601 on the end faces 312 and 412 can be further suppressed.
  • a carrier brush having resin bristles such as nylon or high-pressure water having a pressure of about 7 MPa in the polishing process of the glass substrate 1. Since the end surfaces 312 and 412 of the polishing pads 310 and 410 are inclined with respect to the processing surfaces 311 and 411, even if the
  • the double-side polishing apparatus 1000 described above is used for polishing the glass substrate 1 in the second polishing polishing process (precision polishing) (step S34) which is the final polishing process among the polishing processes (step S30) shown in FIG. Is desirable.
  • the quality of the final glass substrate 1 can be ensured by reducing the deposits, so that the yield of the glass substrate 1 is surely obtained. Can be improved.
  • the polishing polishing process is further performed after the chemical strengthening process (step S40)
  • the polishing process after the chemical strengthening process (step S40) is not described in the second polishing process (step S34).
  • the glass substrate 1 may be polished using the double-side polishing apparatus 1000.
  • FIG. 11 is a diagram showing an evaluation result obtained by polishing the glass substrate 1 using the double-side polishing apparatus 1000 of the example and the comparative example.
  • an annular plate-shaped glass substrate 1 having an outer diameter of 65 mm, an inner diameter of 20 mm, and a thickness of 0.8 mm was prepared, and the yield rate when 100 glass substrates 1 were polished was evaluated.
  • step S33 shows the conditions of the polishing pads 310 and 410 used in the first polishing step (step S33) shown in FIG. 3, and the conditions of the polishing pads 310 and 410 used in the second polishing step (step S34). , Is described. Under any of the conditions, 100 separate glass substrates prepared by the processing up to the previous step were used, processing was performed 15 times for each experimental level, and the processing content of the 15th time was taken as an example or a comparative example.
  • the first polishing step general hard urethane polishing pads 310 and 410 were used, and the type of slurry was cerium oxide slurry having a particle size of about 1.0 ⁇ m.
  • the angle formed between the processed surfaces 311 and 411 of the polishing pads 310 and 410 and the end surfaces 312 and 412 is 90 °.
  • the polishing pads 310 and 410 in which the angle between the processing surfaces 311 and 411 and the end surfaces 312 and 412 is 135 ° and the end surfaces 312 and 412 are inclined with respect to the processing surfaces 311 and 411 are used.
  • the glass substrate 1 was processed so as not to overhang the glass substrate 1 during processing. For each polishing, the surfaces of the polishing pads 310 and 410 were cleaned with a carrier brush.
  • the second polish polishing step general suede polishing pads 310 and 410 were used, and the type of slurry was silica slurry having a particle size of about 20 nm.
  • the angle formed between the processed surfaces 311 and 411 of the polishing pads 310 and 410 and the end surfaces 312 and 412 is 90 °.
  • the angle formed between the processed surfaces 311 and 411 and the end surfaces 312 and 412 is 135 °.
  • the angle formed between the processed surfaces 311 and 411 and the end surfaces 312 and 412 is 100 °.
  • the polishing pads 310 and 410 whose end faces 312 and 412 are inclined with respect to the processing surfaces 311 and 411 are used.
  • the glass substrate 1 was overhanged during the polishing process. The overhang length at this time was 1 mm.
  • the surfaces of the polishing pads 310 and 410 were cleaned with a carrier brush.
  • the yield rate of the glass substrate 1 was evaluated by visual inspection of the surface of the glass substrate 1 using a surface inspection device SSI-640 manufactured by System Seiko Co., Ltd. using a He—Ne laser light source.
  • a surface inspection device SSI-640 manufactured by System Seiko Co., Ltd. using a He—Ne laser light source.
  • defects generated on the surface of the glass substrate 1 such as convex portions (bumps), concave portions (pits), dust (particles), and scratches (scratches) are detected.
  • a defective product was detected when the number of detected defects exceeded a predetermined threshold.
  • the end surfaces 312 and 412 of the polishing pads 310 and 410 are inclined to form the glass substrate 1.
  • a significant improvement in the yield rate was observed.
  • the glass substrate 1 is compared with Example 1. It was confirmed that the yield rate was further improved.
  • the end surfaces 312 and 412 of the polishing pads 310 and 410 form a part of a conical surface, and the processing surfaces 311 and 411 and the end surfaces 312 and 412 are between them.
  • the example in which the circular boundaries 313 and 413 are formed has been described.
  • the shape of the end faces 312 and 412 is not limited to this example.
  • the end surface may be a curved surface represented by a partial shape of a spherical surface, a partial shape of a paraboloid, or the like.
  • the tangent plane to the curved surface at the boundary between the curved surface and the machining surface forms an angle that is not perpendicular to the machining surface, and the tangent plane is an angle larger than 90 ° with respect to the machining surface, preferably 95 ° or more.
  • An angle of 170 ° or less may be formed and inclined.
  • the polishing process which is a process of smoothing both the main surfaces 1A and 1B of the glass substrate 1 using the polishing pads 310 and 410, has been described.
  • the present invention may be applied not only to the polishing process but also to a grinding process which is a machining process with an improvement in dimensional accuracy of both the main surfaces 1A and 1B of the glass substrate 1, for example.

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

Abstract

L'invention concerne un procédé de fabrication d'un substrat de verre pour support d'enregistrement d'informations grâce auquel on peut supprimer l'accumulation d'impuretés sur la surface terminale d'un outil d'usinage. Dans ce procédé de fabrication d'un substrat de verre pour support d'enregistrement d'informations, on forme une couche magnétique d'enregistrement sur la surface principale d'un substrat de verre, le procédé comprenant les étapes consistant à: constituer un substrat de verre; et amener la surface usinée (311) d'un tampon à polir (310) au contact de la surface principale, le tampon à polir comportant la surface usinée plate(311) pour polir la surface principale et une surface terminale (312) constituant le bord périphérique de la surface usinée (311), et faire glisser le tampon à polir (310) contre la surface principale pour usiner celle-ci. La surface terminale (312) est inclinée sous un angle supérieur à 90° par rapport à la surface usinée (311).
PCT/JP2011/072949 2011-03-29 2011-10-05 Procédé de fabrication d'un substrat de verre pour support d'enregistrement d'informations et support d'enregistrement d'informations WO2012132073A1 (fr)

Priority Applications (1)

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JP2013507042A JPWO2012132073A1 (ja) 2011-03-29 2011-10-05 情報記録媒体用ガラス基板の製造方法および情報記録媒体

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JP2011072504 2011-03-29
JP2011-072504 2011-03-29

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Cited By (1)

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WO2018012097A1 (fr) * 2016-07-13 2018-01-18 株式会社Sumco Dispositif pour polissage double face

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JP2002252191A (ja) * 2001-02-26 2002-09-06 Mitsubishi Materials Silicon Corp 半導体ウェーハの研磨装置
JP2006147731A (ja) * 2004-11-17 2006-06-08 Komatsu Electronic Metals Co Ltd 研磨クロス，ウェーハ研磨装置及びウェーハ製造方法
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Publication number Priority date Publication date Assignee Title
WO2018012097A1 (fr) * 2016-07-13 2018-01-18 株式会社Sumco Dispositif pour polissage double face
US11440157B2 (en) 2016-07-13 2022-09-13 Sumco Corporation Dual-surface polishing device and dual-surface polishing method

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