WO2013118648A1 - Method for producing glass product and method for producing magnetic disk - Google Patents

Method for producing glass product and method for producing magnetic disk Download PDF

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Publication number
WO2013118648A1
WO2013118648A1 PCT/JP2013/052337 JP2013052337W WO2013118648A1 WO 2013118648 A1 WO2013118648 A1 WO 2013118648A1 JP 2013052337 W JP2013052337 W JP 2013052337W WO 2013118648 A1 WO2013118648 A1 WO 2013118648A1
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Prior art keywords
glass
cerium
producing
based abrasive
glass product
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PCT/JP2013/052337
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French (fr)
Japanese (ja)
Inventor
宮谷　克明
昌彦 田村
ティップパヤン パリチャット
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旭硝子株式会社
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Application filed by 旭硝子株式会社 filed Critical 旭硝子株式会社
Priority to CN201380008201.XA priority Critical patent/CN104093524A/en
Publication of WO2013118648A1 publication Critical patent/WO2013118648A1/en

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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
    • B24B37/00—Lapping machines or devices; Accessories
    • 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
    • B24B37/044—Lapping machines or devices; Accessories designed for working plane surfaces operating processes therefor characterised by the composition of the lapping agent
    • 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
    • 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 product.
  • a cerium-based abrasive abrasive based on a rare earth metal oxide containing cerium oxide
  • a cerium-based abrasive that is suitably used for glass polishing because of a high polishing rate is a foreign matter. It is known that it tends to remain as.
  • the photomask substrate as a polishing step, after polishing with a slurry containing a cerium-based abrasive, it is often polished using colloidal silica to further planarize the main surface.
  • colloidal silica When the cerium-based abrasive is adhered to the end face, there is a possibility of re-adhering to the surface.
  • a photomask substrate a high transmittance with respect to ultraviolet rays having a short wavelength is required, and scattering due to foreign matters adhering to the surface often becomes a problem.
  • cerium-based abrasive is completely removed at the stage where all the polishing using the cerium-based abrasive is completed.
  • the present invention has been made in view of the above problems, and has undergone a polishing process for polishing glass using a cerium-based abrasive, and a cleaning process for cleaning glass with a cleaning liquid containing heated sulfuric acid and hydrogen peroxide.
  • An object of the present invention is to provide a method for producing a glass product, which can prevent the surface roughness of the glass.
  • the present inventor first polished the glass using a cerium-based abrasive containing no LaOF crystal in the glass polishing step, and then washed the glass with a cleaning solution containing heated sulfuric acid and hydrogen peroxide solution.
  • the inventors have found that the surface roughness of the glass as described above can be suppressed, and have completed the present invention.
  • a method for producing a glass product comprising: a polishing step of polishing a glass using a cerium-based abrasive; and a cleaning step of cleaning the glass using a cleaning liquid containing heated sulfuric acid and hydrogen peroxide.
  • a method for producing a glass product wherein the cerium-based abrasive is a cerium-based abrasive that does not contain LaOF crystals.
  • the method for producing a glass product of the present invention after polishing glass with a cerium-based abrasive not containing LaOF crystals, the glass is washed with a detergent containing heated sulfuric acid and hydrogen peroxide. Further, the adhesion of the cerium-based abrasive to the glass can be effectively suppressed, and the glass surface can be prevented from being rough and a glass product excellent in flatness can be obtained.
  • the conventional glass product manufacturing method after removing the cerium-based abrasive from the glass by a pre-cleaning step using pure water after the step of polishing the glass using the cerium-based abrasive, heated sulfuric acid and peroxide The glass is cleaned using a cleaning agent containing hydrogen water.
  • the method for producing a glass product of the present invention after the polishing step of polishing the glass using a cerium-based abrasive, heating is performed following the polishing step without passing through a preliminary cleaning step with pure water or the like. Even when the glass is cleaned using a cleaning agent containing sulfuric acid and hydrogen peroxide solution, the glass can be prevented from roughing and flatness can be obtained, which is also excellent from the viewpoint of production efficiency.
  • FIG. 1 shows a crystal phase of a cerium-based abrasive analyzed by an X-ray diffraction method.
  • FIG. 2 (a) shows that after polishing the glass with a cerium-based abrasive containing LaOF crystals, the glass is cleaned with a cleaning agent containing heated sulfuric acid and hydrogen peroxide solution. It is a figure explaining the mechanism which arises.
  • FIG. 2B shows that the glass is roughened by polishing the glass with a cerium-based abrasive containing no LaOF crystal and then washing the glass with a detergent containing heated sulfuric acid and hydrogen peroxide. It is a figure explaining that does not arise.
  • FIG. 2 (a) shows that after polishing the glass with a cerium-based abrasive containing LaOF crystals, the glass is cleaned with a cleaning agent containing heated sulfuric acid and hydrogen peroxide solution. It is a figure explaining the mechanism which arises.
  • FIG. 2B shows that the glass is roughened
  • FIG. 3 shows the crystal phase of the cerium-based abrasive used in Example 1 analyzed by the X-ray diffraction method.
  • FIG. 4 shows the crystal phase of the cerium-based abrasive used in Example 2, analyzed by the X-ray diffraction method.
  • FIG. 5 shows the crystal phase of the cerium-based abrasive used in Example 3, analyzed by X-ray diffraction.
  • FIG. 6 shows the crystal phase of the cerium-based abrasive used in Comparative Example 1 analyzed by the X-ray diffraction method.
  • FIG. 7 shows the crystal phase of the cerium-based abrasive used in Comparative Example 2 analyzed by the X-ray diffraction method.
  • FIG. 4 shows the crystal phase of the cerium-based abrasive used in Example 2, analyzed by the X-ray diffraction method.
  • FIG. 5 shows the crystal phase of the cerium-based abrasive used in Example 3, analyzed
  • FIG. 8 shows the crystal phase of the cerium-based abrasive used in Comparative Example 3, analyzed by X-ray diffraction.
  • FIG. 3 is a diagram showing surface roughness of a glass substrate observed by a white interference method (Examples 1 to 3, Comparative Examples 1 to 3).
  • the present inventors investigated the phenomenon that a large surface roughness occurs in the glass when a cleaning solution containing heated sulfuric acid and hydrogen peroxide water is used for cleaning after the final polishing step of the glass. It has been found that when this cleaning is performed when an agent is attached, partial surface roughness occurs on the glass surface.
  • cleaning using a cleaning solution containing heated sulfuric acid and hydrogen peroxide water refers to cleaning with a cleaning solution containing sulfuric acid and hydrogen peroxide solution heated to 45 ° C. or higher, and the temperature is typically 60 ° C. or higher. Is 70 ° C. or higher.
  • the surface deposits were washed with a cleaning solution containing heated sulfuric acid and hydrogen peroxide.
  • the dent defect in the glass was observed by an optical measurement method using Optiflat manufactured by ADE.
  • the crystal phase of the cerium-based abrasive in which the dent defect is generated was examined by an X-ray diffraction method, as shown in FIG. 1, the cerium-based abrasive in which the dent defect was observed had a fluorite structure crystal (Ce x La 1).
  • the LaOF crystal contained in the ceria-based polishing agent is a cause of the dent. From this result, by using a ceria-based abrasive that does not contain LaOF crystals for polishing glass, the occurrence of dent defects is suppressed even if the glass is subsequently cleaned with a cleaning solution containing sulfuric acid and hydrogen peroxide. As a result, the present invention has been achieved. That is, if a ceria-based abrasive not containing La or F is used, a dent defect does not occur.
  • the lanthanum oxyfluoride (LaOF) contained in the cerium-based abrasive is considered to cause the surface roughness of the glass by the following mechanism.
  • LaOF is dissolved in the cleaning solution containing heated sulfuric acid and hydrogen peroxide solution, and fluorine ions (F ⁇ ) contained in LaOF are mixed with H + or H 2 O in the cleaning solution. It reacts to function as hydrogen fluoride (HF), and the glass is etched as shown in the following formula (1) to produce H 2 SiF 6 .
  • H 2 SiF 6 is soluble in water, the amount of water in the cleaning solution containing heated sulfuric acid and hydrogen peroxide water is small, so that it reacts with a small amount of H 2 O according to the following formula (2) to form H 2 SiO 3. It becomes. Since H 2 SiO 3 is insoluble in the acidic cleaning solution, it becomes a gel-like deposit on the glass surface, and the glass is polished by subsequent scrub cleaning or finish polishing, so that the H 2 SiO 3 attached to the glass is removed. As the glass is removed, the glass is dented, and the glass becomes rough. H 2 SiF 6 + H 2 O ⁇ H 2 SiO 3 + 6HF (2)
  • the glass product in the present invention is not particularly limited, but is typically a glass substrate such as a magnetic disk glass substrate or a photomask substrate.
  • a glass substrate for a magnetic disk will be described as an example, but the present invention is not limited to this example.
  • SiO 2 is 55 to 75%
  • Al 2 O 3 is 5 to 17%
  • Li 2 O + Na 2 O + K 2 O is 4 to 27%
  • MgO + CaO + SrO + BaO is cut out from a glass plate made of glass containing 0 to 20% and the total content of these components being 90% or more.
  • SiO 2 is a component that forms a glass skeleton and is essential.
  • the content of SiO 2 is preferably 60% or more, more preferably 61% or more, particularly preferably 62% or more, most preferably 63% or more, and typically 64% or more.
  • the Young's modulus is prevented from being lowered, the specific elastic modulus is improved, the thermal expansion coefficient is prevented from being reduced, or the viscosity is not excessively increased. Glass can be easily melted.
  • the content of SiO 2 is preferably 71% or less, more preferably 70% or less, and most preferably 68% or less. Incidentally, the acid resistance is hardly lowered by setting the content of SiO 2 63 mol% or more.
  • Al 2 O 3 is a component that forms a glass skeleton and increases Young's modulus, specific elastic modulus, and fracture toughness, and is essential. By setting the content of Al 2 O 3 to 5% or more, the Young's modulus, specific elastic modulus, or fracture toughness can be prevented from being lowered.
  • the content of Al 2 O 3 is preferably 6% or more, more preferably 7% or more, and typically 8% or more. Further, by making the content of Al 2 O 3 17% or less, it is possible to prevent the coefficient of thermal expansion from becoming small, to facilitate the melting of the glass without excessively increasing the viscosity, or to reduce the acid resistance. prevent.
  • the content of Al 2 O 3 is preferably 15% or less, more preferably 14% or less. The acid resistance is less likely to be lowered by setting the content of Al 2 O 3 to 12.5% or less.
  • the glass having a large amount of SiO 2 and a small amount of Al 2 O 3 is unlikely to deteriorate in acid resistance. For this reason, when (SiO 2 —Al 2 O 3 ) increases, the acid resistance of the glass improves.
  • the mechanical properties such as Young's modulus, specific elastic modulus, or fracture toughness, it is effective that there is a large amount of Al 2 O 3 , and glass excellent in mechanical properties tends to have low acid resistance.
  • (SiO 2 —Al 2 O 3 ) is typically 48 to 62%.
  • Li 2 O, Na 2 O and K 2 O are components that improve the solubility of the glass and increase the thermal expansion coefficient, and must contain at least one component. This effect is enhanced by setting the total R 2 O content of these three components to 4% or more.
  • the total R 2 O content of the three components is preferably 13% or more, more preferably 15% or more, particularly preferably 16% or more, most preferably 17% or more, and typically 18% or more. Further, it is preferable that the total R 2 O content of the three components is 27% or less because Young's modulus, specific elastic modulus, or fracture toughness is improved, or alkali is hardly eluted by reaction with moisture.
  • the total R 2 O content of the three components is preferably 25% or less, more preferably 24% or less, and particularly preferably 22% or less. R 2 O is typically 16-24%.
  • Li 2 O is preferably contained in an amount of 5% or more because it has a high effect of increasing Young's modulus, specific elastic modulus, and fracture toughness. More preferably, it is 7% or more, and most preferably 8% or more.
  • MgO, CaO, SrO and BaO are not essential, but are components that improve the solubility of the glass and increase the thermal expansion coefficient, and the total R′O content of these four components is in the range of up to 20%. You may contain. When the total R′O of the contents of the four components is 20% or less, the specific gravity is prevented from increasing or the glass is hardly damaged.
  • the total R′O content of the four components is preferably 10% or less, more preferably 8% or less, most preferably 6% or less, and typically 4% or less.
  • SiO 2 + Al 2 O 3 + R 2 O + R′O is preferably 90% or more. This effect is enhanced by setting SiO 2 + Al 2 O 3 + R 2 O + R′O to 90% or more.
  • SiO 2 + Al 2 O 3 + R 2 O + R′O is preferably 93% or more, more preferably 95% or more, and most preferably 97% or more.
  • This exemplary glass consists essentially of the above components, but may contain other components as long as the object of the present invention is not impaired.
  • TiO 2 , ZrO 2 , Y 2 O 3 , Nb 2 O 5 , Ta 2 O 5 and La 2 O 3 have an effect of increasing Young's modulus, specific elastic modulus, or fracture toughness.
  • the total content is preferably 7% or less. By making it 7% or less, the specific gravity is prevented from becoming large, or the glass is hardly damaged.
  • the total content of these components is more preferably less than 5%, particularly preferably less than 4%, most preferably less than 3%.
  • B 2 O 3 has the effects of improving the solubility of the glass, reducing the specific gravity, and making the glass difficult to damage. When it contains this, 3% or less is preferable. By setting it to 3% or less, the Young's modulus or specific elastic modulus can be prevented from being lowered, or the glass quality can be prevented from being deteriorated by volatilization.
  • the content of B 2 O 3 is more preferably 2% or less, particularly preferably 1% or less, and most preferably 0.5% or less.
  • SO 3 , Cl, As 2 O 3 , Sb 2 O 3 , SnO 2 and CeO 2 have the effect of clarifying the glass.
  • the total content is preferably 2% or less.
  • Synthetic quartz glass is a glass made of substantially only silicon oxide obtained by, for example, growing a porous body made of silicon oxide called soot by reacting a silicon source and an oxygen source in a gas phase and sintering.
  • soot a porous body made of silicon oxide called soot by reacting a silicon source and an oxygen source in a gas phase and sintering.
  • the specific gravity of the glass plate is preferably 2.60 or less. By setting the specific gravity of the glass plate to 2.60 or less, it is possible to prevent the motor load from being applied during the rotation of the magnetic disk drive and to reduce the power consumption, or to stabilize the drive rotation.
  • the specific gravity of the glass is preferably 2.55 or less, more preferably 2.53 or less, and most preferably 2.52 or less.
  • the thermal expansion coefficient (average linear expansion coefficient) in the range of ⁇ 50 to + 70 ° C. of the glass plate is preferably 60 ⁇ 10 ⁇ 7 / ° C. or more.
  • the thermal expansion coefficient (average linear expansion coefficient) in the range of ⁇ 50 to + 70 ° C. of the glass plate is preferably 62 ⁇ 10 ⁇ 7 / ° C. or more, more preferably 65 ⁇ 10 ⁇ 7 / ° C. or more, and most preferably 70 ⁇ . 10 ⁇ 7 / ° C. or higher.
  • the Young's modulus of the glass plate is 80 GPa or more and the specific elastic modulus is 32 MNm / kg or more. If the Young's modulus is 80 GPa or more or the specific elastic modulus is 32 MNm / kg or more, warping or deflection is unlikely to occur during drive rotation, and an information recording medium having a high recording density can be easily obtained.
  • the Young's modulus of the glass plate is more preferably 81 GPa or more and the specific modulus is 32.5 MNm / kg or more.
  • the glass plate made of the above exemplary glass tends to be excellent in various properties such as Young's modulus, specific elastic modulus, specific gravity, thermal expansion coefficient, scratch resistance or fracture toughness.
  • the manufacturing method of a glass plate is not specifically limited, Various methods can be applied.
  • the raw materials of each component normally used are prepared so as to have a target composition, and this is heated and melted in a glass melting kiln. Homogenize the glass by bubbling, stirring or adding a clarifying agent, etc., and forming it into a sheet glass of a predetermined thickness by a method such as the well-known float method, press method, fusion method or downdraw method, and after slow cooling, as necessary After processing such as grinding and polishing, a glass substrate having a predetermined size and shape is obtained.
  • a float method suitable for mass production is particularly preferable.
  • continuous molding methods other than the float method for example, a fusion method or a downdraw method are also preferable.
  • the main surface lapping step may be divided into a rough lapping step and a fine lapping step, and a shape processing step (drilling at the center of the circular glass plate, chamfering, end polishing) may be provided between them.
  • End mirror mirror polishing may be performed by laminating glass discs and brushing the inner peripheral end surface using a cerium-based abrasive and performing etching, or by etching instead of brushing the inner peripheral end surface.
  • a polysilazane compound-containing liquid may be applied to the treated inner peripheral end face by a spray method or the like, and baked to form a coating (protective coating) on the inner peripheral end face.
  • the main surface lapping is usually performed using aluminum oxide abrasive grains having an average particle diameter of 6 to 8 ⁇ m or abrasive grains made of aluminum oxide.
  • the lapped main surface is usually preferably polished by 30 to 40 ⁇ m.
  • the manufacturing method of the glass product of this invention includes the grinding
  • the cerium-based abrasive is an abrasive that does not contain LaOF crystals. Further, the cerium-based abrasive may be an abrasive that does not contain a crystal obtained by substituting part of La of LaOF crystal with Ce.
  • the cerium-based abrasive used in the production method of the present invention preferably contains Ce x La 1-x O y F 2-y having a fluorite structure when it contains La.
  • x is 0.5 or more and less than 1
  • y is 1.7 to 2.
  • y is less than 2.
  • a cerium-based abrasive used in glass polishing particularly a cerium-based abrasive used in the manufacture of a glass substrate for a magnetic disk or a glass substrate for a photomask, has a fluorite-type structure Ce x La 1-x from the viewpoint of cost reduction. In general, it contains O y F 2-y (x is 0.5 or more and less than 1, y is 1.7 to 2) and LaOF crystals.
  • LaOF dissolves in the cleaning solution containing heated sulfuric acid and hydrogen peroxide solution, and fluorine contained in the LaOF crystal functions as hydrofluoric acid. As a result, the glass is etched and surface roughness occurs. For this reason, in the present invention, a cerium-based abrasive that does not contain LaOF crystals is used.
  • the cerium-based abrasive used in the present invention may be dispersed in a dispersion medium such as water and used as a slurry. 1 mass% or more and 20 mass% or less are preferable, and, as for content of the cerium type abrasive
  • the content of the cerium-based abrasive in the slurry By setting the content of the cerium-based abrasive in the slurry to 1% by mass or more, a sufficient polishing rate can be obtained. Moreover, by setting it as 20 mass% or less, it can suppress that a slurry viscosity raises by the influence of the glass component mixed in a slurry during grinding
  • Examples of the dispersion medium that can be used for the slurry include water.
  • the slurry may contain a surfactant as a dispersant or a lubricant.
  • a surfactant as the dispersant include an anionic surfactant, a cationic surfactant, a nonionic surfactant, a zwitterionic surfactant, and the like, or a combination thereof.
  • phosphate salts such as sodium diphosphate and sodium phosphonate
  • carboxylate salts such as sodium citrate
  • monomer salts such as sulfonate salts such as sodium lignin sulfonate and sodium naphthalene sulfonate, or These combinations can be mentioned.
  • the content of the dispersant in the cerium-based abrasive is preferably 0.5 to 2% by mass with respect to the abrasive grains.
  • the surfactant as the lubricant include non-foaming surfactants such as alkylene diol.
  • the content of the surfactant in the cerium-based abrasive is preferably 0.01 to 1% by mass.
  • the average particle size of the cerium-based abrasive is preferably 0.1 ⁇ m or more and 0.5 ⁇ m or less considering that the glass cleaning time in the glass product manufacturing process is usually 5 to 20 minutes.
  • the average particle size of the cerium-based abrasive is measured using laser scattering. In the case of this measurement, it is preferable to measure by mixing about 1% by mass of any of the above dispersants with respect to the abrasive so that measurement can be performed in a sufficiently dispersed slurry.
  • a sufficient polishing rate can be obtained by setting the average particle diameter of the cerium-based abrasive to 0.1 ⁇ m or more. Also, by setting the average particle size of the cerium-based abrasive to 0.5 ⁇ m or less, the area in contact with the glass is small, and the surface layer is only slightly melted so that it can be easily peeled off from the glass. The amount of elution is sufficient, and the washability can be improved.
  • the cerium-based abrasive used in the present invention contains fluorine, it does not contain LaOF crystals. Therefore, when cleaning is performed using a cleaning solution containing heated sulfuric acid and hydrogen peroxide, fluorine contained in LaOF crystals is hydrofluoric acid. It is possible to prevent the glass from being etched and causing surface roughness.
  • the cerium-based abrasive used in the present invention contains fluorine, its content is preferably 4% by mass or less, more preferably 3% by mass or less, and 0.1% by mass or less. It is particularly preferred. From the viewpoint of the following effects, the fluorine content is preferably more than 1% by mass. Fluorine is considered to have an effect of lowering the valence of cerium, that is, an effect of improving chemical polishing power, when substituted with oxygen on the surface of the CeO 2 crystal. However, since such an effect can be obtained only by substituting part of oxygen on the surface of the CeO 2 crystal, the content of fluorine in the cerium-based abrasive is preferably 4% by mass or less.
  • the cerium valence on the surface of the abrasive grains can be easily taken to be trivalent, and the Si—O bond on the glass surface is weakened and polished. It becomes easy to be done.
  • cerium-based abrasive used in the present invention examples include cerium-based abrasives containing lanthanum.
  • the lanthanum contained in the cerium-based abrasive is preferably Ce X La 1-X O y F 2-Y (x is 0.5 or more and less than 1, y is 1.7 to 2).
  • the cerium-based abrasive preferably contains 20 to 40% by mass, more preferably 30 to 40% by mass of lanthanum as La 2 O 3 . By setting the content of La 2 O 3 in the cerium-based abrasive within this range, a high polishing rate can be obtained.
  • the polishing method in the present invention is not particularly limited.
  • the glass and the polishing cloth are brought into contact with each other, and the polishing cloth and the glass are relatively moved while supplying the cerium-based abrasive, so that the glass is mirror-like. It is preferable to polish.
  • the polishing cloth for example, a urethane polishing pad can be used.
  • polishing step for example, a waviness (Wa) measured using a three-dimensional surface structure analyzer [for example, ADE Opti-flat (trade name)] under a condition where the wavelength region is ⁇ ⁇ 5 mm. It is preferable to polish so that it may become 1 nm or less. Further, the reduction amount of the plate thickness due to polishing (polishing amount) is typically preferably 5 to 15 ⁇ m.
  • the polishing step may be performed once, or may be performed twice or more using a cerium-based abrasive having different average particle diameters.
  • polishing agent may contain a well-known LaOF crystal
  • the polishing step in the present invention includes a cerium oxide main surface polishing step for removing scratches generated in the lapping step, but is not limited to this, and includes end surface mirror polishing with cerium oxide after the lapping step.
  • Preliminary cleaning You may perform preliminary washing
  • immersion cleaning with pure water or rinsing with pure water ultrasonic cleaning may be used in combination, or running water or shower water may be used.
  • the glass disc that has been polished is cleaned with a cleaning solution containing heated sulfuric acid and hydrogen peroxide without pre-cleaning.
  • a cleaning solution containing heated sulfuric acid and hydrogen peroxide without pre-cleaning.
  • the polished glass disc may be dried. Drying is performed, for example, by spin drying.
  • the method for producing a glass product of the present invention includes a step of cleaning the cerium-based abrasive adhering to the glass using a cleaning liquid containing heated sulfuric acid and hydrogen peroxide (hereinafter, this cleaning is referred to as cleaning in the present invention, this The cleaning liquid is also referred to as a cleaning liquid used in the present invention).
  • the content of sulfuric acid in the cleaning liquid used in the present invention is preferably 55 to 80% by mass, more preferably 60% by mass or more, and still more preferably 65% by mass or more.
  • content of sulfuric acid 55 mass% or more, it can prevent that the cerium type abrasive
  • sulfuric acid content 80% by mass or less surface roughness due to leaching can be prevented, the intended flatness can be easily obtained, and resin jigs that are generally used in cleaning devices are oxidized and decomposed. Can be prevented.
  • the content of hydrogen peroxide in the cleaning liquid used in the present invention is preferably 1 to 10% by mass, more preferably 2% by mass or more, and further preferably 4% by mass or more.
  • the content of hydrogen peroxide is preferably 1 to 10% by mass, more preferably 2% by mass or more, and further preferably 4% by mass or more.
  • the temperature of the cleaning liquid used in the present invention is preferably 70 to 100 ° C. Further, it is more preferably 75 ° C. to 90 ° C. By setting the temperature of the cleaning liquid to 70 ° C. or higher, the cerium-based abrasive is less likely to remain on the glass. In addition, by setting the temperature of the cleaning liquid to 100 ° C. or lower, it is possible to suppress the decomposition of hydrogen peroxide and prevent the cleaning liquid composition from changing.
  • the other component in the cleaning liquid used in the present invention is usually preferably water. That is, it is preferable that the cleaning liquid used in the present invention is usually an aqueous solution, and even in that case, it may contain components other than water as long as the object of the present invention is not impaired. Examples of water include deionized water, ultrapure water, charged ion water, hydrogen water, and ozone water.
  • the time for the washing step is typically 5 minutes or longer, and usually the washing purpose can be achieved in 30 minutes or less.
  • the cleaning liquid used in the present invention may contain a surfactant for the purpose of reducing the surface tension of the liquid.
  • the surfactant include carboxylates such as polyacrylates, polymaleates and polyitaconates, and sulfonic acids such as alkyl sulfonates.
  • the content of the surfactant in the cleaning liquid is not particularly limited, but is preferably 1% by mass or less.
  • the cleaning step it is preferable to perform cleaning by bringing the cleaning liquid into direct contact with glass.
  • the method of bringing the cleaning liquid into direct contact with the glass include, for example, dip-type cleaning in which the cleaning liquid is filled in a cleaning tank, and glass is placed therein, a method of spraying the cleaning liquid from the nozzle onto the glass, and scrub cleaning using a sponge made of polyvinyl alcohol Etc.
  • the cleaning liquid used in the present invention can be applied to any of these methods, but dip-type cleaning is preferred because more efficient cleaning can be performed.
  • the time for immersing the glass in the cleaning liquid is 2 minutes or more.
  • ultrasonic cleaning together during the contact it is more preferable to use ultrasonic cleaning together during the contact.
  • the final polishing is usually performed using a slurry containing colloidal silica abrasive grains.
  • polishing is usually performed using a slurry containing colloidal silica abrasive grains having an average particle diameter of 10 to 50 nm, but before that, a slurry containing colloidal silica abrasive grains having an average particle diameter of more than 50 nm and 100 nm or less is used. It may be used for prepolishing. Further, chemical strengthening may be performed before or after polishing with a slurry containing colloidal silica abrasive grains.
  • colloidal silica using water glass as a raw material generally tends to undergo gelation in a neutral region, and therefore it is preferable to carry out at a pH of 1 to 6 or 2 to 6. .
  • an inorganic acid or an organic acid is used as long as it is an acid.
  • inorganic acids include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, polyphosphoric acid, amidosulfuric acid, and the like.
  • organic acid carboxylic acid, organic phosphoric acid, an amino acid etc. are mentioned, for example.
  • carboxylic acid include monovalent carboxylic acids such as acetic acid, glycolic acid and ascorbic acid, divalent carboxylic acids such as succinic acid and tartaric acid, and trivalent carboxylic acids such as citric acid.
  • the pH is preferably 1 to 3, in which case it is preferable to use an inorganic acid.
  • the pH is higher than 3, it is preferable to use carboxylic acid because gelation of colloidal silica abrasive grains can be suppressed.
  • an anionic or nonionic surfactant may be added to the slurry.
  • the polishing tool is preferably a suede pad.
  • This suede pad has a foamed resin layer, preferably has a Shore A hardness of 20 ° to 60 °, and a density of 0.2 to 0.8 g / cm 3 .
  • the glass disk is preferably polished by the final polishing step so that the root mean square roughness (Rms) of the main surface is preferably 0.15 nm or less, more preferably 0.13 nm or less.
  • a reduction amount (polishing amount) of the plate thickness in this polishing is typically 0.5 to 2 ⁇ m.
  • cleaning is performed to remove the colloidal silica abrasive grains.
  • this cleaning step it is preferable to perform cleaning with an alkaline cleaning agent having a pH of 10 or more at least once.
  • an alkaline cleaning agent having a pH of 10 or more at least once.
  • ultrasonic vibration may be applied by immersing a glass disk, or scrub cleaning may be used. Moreover, you may combine both.
  • the glass disk is dried after the final rinsing step.
  • a drying method for example, a drying method using isopropyl alcohol vapor, spin drying or vacuum drying is used.
  • the glass product manufactured by the manufacturing method of the present invention has 0 or 1 surface or less concave defects having a size of 1 mm ⁇ 1 mm or more.
  • the observation of the dent defect is performed by the method described later in the examples.
  • glass products produced by the production method of the present invention include glass substrates for magnetic disks, glass substrates such as photomask substrates and display substrates, and blue filter glass and cover glass for CCDs.
  • a magnetic disk can be manufactured by forming a magnetic recording layer on the main surface of a glass substrate for a magnetic disk manufactured by the manufacturing method of the present invention. According to the magnetic disk in which the magnetic recording layer is formed on the main surface of the highly flattened glass substrate obtained by the manufacturing method of the present invention, high density recording is possible.
  • chamfering was performed on the inner and outer end faces by providing a chamfered portion having a width of 0.15 mm and an angle of 45 °.
  • the end surfaces of the inner and outer periphery were mirror-finished by brush polishing using a slurry containing a cerium-based abrasive as an abrasive and using a brush as an abrasive.
  • the removal amount in the radial direction was 30 ⁇ m.
  • the upper and lower main surfaces were polished by a double-side polishing apparatus using a slurry containing a cerium-based abrasive shown in Table 1 or 2 as an abrasive and a urethane pad as a polishing tool.
  • the amount of polishing was 5 ⁇ m in total in the thickness direction of the upper and lower main surfaces.
  • Example 2 a product obtained by purifying a normal product as a cerium-based abrasive was used.
  • the structure obtained from X-ray diffraction is “single phase” and verified based on powder diffraction data provided by International Center for Diffraction Data (registered trademark) [ICDD (registered trademark)].
  • ICDD International Center for Diffraction Data
  • the peak position of the fluorite-type cerium oxide particles coincides with the peak position, or all peaks are within the range of ⁇ 0.5 °, and “two or more phases” means “International Center”.
  • the peak coincides with the peak position of cerium oxide particles having a fluorite structure within ⁇ 5 ° This indicates that there is a peak other than.
  • the main surface of the glass disk is polished, dried for 2 hours, heated at 70 ° C. for 1 hour, and then heated to 80 ° C. containing 74% by mass sulfuric acid and 11.4% by mass hydrogen peroxide. And soaked for 5 minutes.
  • the surface shape of the glass disk thus obtained was measured by Optiflat manufactured by ADE before and after cleaning with a cleaning liquid containing heated sulfuric acid and hydrogen peroxide. The result is shown in FIG. In FIG. 9, the A surface indicates one surface of the glass disk, and the B surface indicates the other surface.
  • the glass was polished by using Examples 1 to 3 in which a slurry containing a cerium-based abrasive having a single-phase crystal structure and containing no LaOF crystals was used.
  • the glass plate was not roughened by cleaning with a cleaning solution containing heated sulfuric acid and hydrogen peroxide.
  • cerium-based abrasives contain the cause of surface roughness caused by polishing glass with a cerium-based abrasive and then cleaning the glass with a cleaning solution containing heated sulfuric acid and hydrogen peroxide.
  • a cerium-based abrasive that does not contain LaOF crystals the glass is polished, and then the glass is washed with a cleaning solution containing heated sulfuric acid and hydrogen peroxide, thereby preventing the formation of dent defects. It was found that a glass having excellent flatness can be obtained by effectively suppressing surface roughness.
  • the manufacturing method of the present invention even when the glass is washed with a cleaning solution containing sulfuric acid and hydrogen peroxide water heated without undergoing a preliminary cleaning step after the polishing step, the occurrence of surface roughness can be suppressed. I understood.

Abstract

The present invention provides a method for producing a glass product, which produces a glass product through a polishing step wherein glass is polished using a cerium-based polishing agent and a cleaning step wherein the glass is cleaned with use of a heated cleaning liquid that contains sulfuric acid and hydrogen peroxide water, and which is capable of preventing surface roughening of the glass. The present invention relates to a method for producing a glass product, which comprises a polishing step wherein glass is polished using a cerium-based polishing agent and a cleaning step wherein the glass is cleaned with use of a heated cleaning liquid that contains sulfuric acid and hydrogen peroxide water after the polishing step, and wherein the cerium-based polishing agent does not contain LaOF crystals.

Description

ガラス製品の製造方法および磁気ディスクの製造方法Manufacturing method of glass product and manufacturing method of magnetic disk
　本発明はガラス製品の製造方法に関する。 The present invention relates to a method for manufacturing a glass product.
　磁気ディスク用ガラス基板またはフォトマスク基板などの高精度な平坦性を要求されるガラス製品の製造方法においては、ガラス製品に残留する異物の除去が大きな技術課題となっている。ガラス製品に残留する異物としては、研磨レートが高いことなどの理由からガラス研磨に好適に用いられているセリウム系研磨剤（酸化セリウムを含む希土類金属酸化物を主成分とする研磨剤）が異物として残りやすいことが知られている。 In a glass product manufacturing method that requires high-precision flatness such as a magnetic disk glass substrate or a photomask substrate, removal of foreign matters remaining on the glass product is a major technical issue. As the foreign matter remaining in the glass product, a cerium-based abrasive (abrasive based on a rare earth metal oxide containing cerium oxide) that is suitably used for glass polishing because of a high polishing rate is a foreign matter. It is known that it tends to remain as.
　例えば、磁気ディスク用ガラス基板の製造工程では、ガラス板から切り出したガラス円板の主表面および端面を、セリウム系研磨剤を含むスラリーを用いて研磨した後、主表面をさらに平坦化するためにコロイダルシリカ砥粒を含むスラリーによる仕上げ研磨（最終研磨）を行う。このとき、主表面にセリウム系研磨剤が残留していても仕上げ研磨により除去される。しかし、端面に付着しているセリウム系研磨剤は除去されずに残留し、仕上げ研磨後の洗浄工程において主表面に再付着し磁気ディスク用ガラス基板に異物として残留すると考えられる。 For example, in the manufacturing process of a glass substrate for a magnetic disk, in order to further planarize the main surface after polishing the main surface and end surface of a glass disk cut out from the glass plate with a slurry containing a cerium-based abrasive. Final polishing (final polishing) is performed with a slurry containing colloidal silica abrasive grains. At this time, even if the cerium-based abrasive remains on the main surface, it is removed by finish polishing. However, it is considered that the cerium-based abrasive adhering to the end face remains without being removed, reattaches to the main surface in the cleaning step after finish polishing, and remains as a foreign substance on the magnetic disk glass substrate.
　また、フォトマスク基板においても磁気ディスク用ガラス基板と同様の課題が存在する。フォトマスク基板に関しても、研磨工程としてはセリウム系研磨剤を含むスラリーで研磨した後、主表面をさらに平坦化する為にコロイダルシリカを用いて研磨される場合が多い。セリウム系研磨剤が端面に付着している場合には、表面に再付着する可能性がある。フォトマスク基板の場合、短波長の紫外線に対する高い透過率が要求されており、表面に付着した異物による散乱が問題になる場合が多い。 Also, the same problem as the glass substrate for magnetic disks exists in the photomask substrate. Also for the photomask substrate, as a polishing step, after polishing with a slurry containing a cerium-based abrasive, it is often polished using colloidal silica to further planarize the main surface. When the cerium-based abrasive is adhered to the end face, there is a possibility of re-adhering to the surface. In the case of a photomask substrate, a high transmittance with respect to ultraviolet rays having a short wavelength is required, and scattering due to foreign matters adhering to the surface often becomes a problem.
　このような背景から、セリウム系研磨剤を用いる研磨がすべて終了した段階ではセリウム系研磨剤が完全に除去されていることが望まれている。 From such a background, it is desired that the cerium-based abrasive is completely removed at the stage where all the polishing using the cerium-based abrasive is completed.
　このような要望に応えるべく、無機酸とアスコルビン酸を含有する洗浄液が提案されている（例えば、特許文献１および２参照）。この洗浄液では、無機酸とアスコルビン酸の作用によって、セリウム系研磨剤を溶かして除去している。 In order to meet such a demand, a cleaning liquid containing an inorganic acid and ascorbic acid has been proposed (see, for example, Patent Documents 1 and 2). In this cleaning solution, the cerium-based abrasive is dissolved and removed by the action of inorganic acid and ascorbic acid.
　また、加熱した硫酸および過酸化水素水を含む洗浄液を最終工程の洗浄にて使用することも提案されている（例えば、特許文献３参照）。 It has also been proposed to use a cleaning solution containing heated sulfuric acid and hydrogen peroxide water in the final cleaning process (see, for example, Patent Document 3).
日本国特開２００６－９９８４７号公報（特許請求の範囲）Japanese Unexamined Patent Publication No. 2006-99847 (Claims) 日本国特開２００４－５９４１９号公報（特許請求の範囲）Japanese Unexamined Patent Publication No. 2004-59419 (Claims) 日本国特開２００８－９０８９８号公報（特許請求の範囲）Japanese Unexamined Patent Publication No. 2008-90898 (Claims)
　しかしながら、本発明者らが上記の洗浄技術について検証したところ、アスコルビン酸および無機酸を含む洗浄液による洗浄では、ガラス円板の端部に残留するセリウム系研磨剤を少なくすることは可能であるものの、完全には除去できない場合があることを確認した。また、この洗浄液はｐＨが１～２と低いため、アルカリアルミノシリケートガラスからなるガラス円板に適用すると大きな面荒れを引き起こす場合があることも確認した。 However, when the present inventors have verified the above-described cleaning technique, it is possible to reduce the amount of cerium-based abrasive remaining on the end of the glass disk by cleaning with a cleaning liquid containing ascorbic acid and inorganic acid. , Confirmed that it may not be completely removed. Further, since this cleaning liquid has a low pH of 1 to 2, it has been confirmed that it may cause a large surface roughness when applied to a glass disk made of alkali aluminosilicate glass.
　一方、加熱した硫酸および過酸化水素水を含む洗浄液を最終研磨工程後の洗浄に使用する場合においては、ガラス基板の端部に残留するセリウム系研磨剤をほぼ完全に除去できるが、ガラス表面にガラスのくずが付着し、該付着物を取り除くと、ガラス表面に凹みが発生して大きな面荒れが起こる場合があることを確認した。 On the other hand, in the case where a cleaning solution containing heated sulfuric acid and hydrogen peroxide is used for cleaning after the final polishing step, the cerium-based abrasive remaining on the edge of the glass substrate can be almost completely removed. It was confirmed that when glass scraps adhered and the deposits were removed, dents were generated on the glass surface, resulting in large surface roughness.
　本発明は上記問題に鑑みてなされたものであり、セリウム系研磨剤を用いてガラスを研磨する研磨工程、および加熱した硫酸と過酸化水素水とを含む洗浄液によりガラスを洗浄する洗浄工程を経てガラス製品を製造する方法であって、ガラスの面荒れを防ぐことができるガラス製品の製造方法の提供を目的とする。 The present invention has been made in view of the above problems, and has undergone a polishing process for polishing glass using a cerium-based abrasive, and a cleaning process for cleaning glass with a cleaning liquid containing heated sulfuric acid and hydrogen peroxide. An object of the present invention is to provide a method for producing a glass product, which can prevent the surface roughness of the glass.
　本発明者は、ガラスの研磨工程において、ＬａＯＦ結晶を含まないセリウム系研磨剤を用いてガラスを研磨し、その後加熱した硫酸および過酸化水素水を含む洗浄液によりガラスを洗浄することにより、先に述べたようなガラスの面荒れを抑制できることを見出し、本発明を完成させた。 The present inventor first polished the glass using a cerium-based abrasive containing no LaOF crystal in the glass polishing step, and then washed the glass with a cleaning solution containing heated sulfuric acid and hydrogen peroxide solution. The inventors have found that the surface roughness of the glass as described above can be suppressed, and have completed the present invention.
　すなわち、本発明は以下の通りである。
１．セリウム系研磨剤を用いてガラスを研磨する研磨工程と、その後に、加熱した硫酸と過酸化水素水とを含む洗浄液を用いてガラスを洗浄する洗浄工程とを含むガラス製品の製造方法であって、該セリウム系研磨剤がＬａＯＦ結晶を含まないセリウム系研磨剤であるガラス製品の製造方法。
２．前記セリウム研磨剤がランタンを含む前項１に記載のガラス製品の製造方法。
３．前記セリウム系研磨剤がランタンをＬａ２Ｏ３として２０～４０質量％含有する前項２に記載のガラス製品の製造方法。
４．前記セリウム系研磨剤がフッ素を含む前項１～３のいずれか１に記載のガラス製品の製造方法。
５．前記セリウム系研磨剤におけるフッ素の含有量が１質量％超である前項４に記載のガラス製品の製造方法。
６．前記セリウム系研磨剤がホタル石型構造のＣｅｘＬａ１－ｘＯｙＦ２－ｙ（ｘは０．５以上１未満、ｙは１．７～２）を含む、前項１～５のいずれか１に記載のガラス製品の製造方法。
７．前記セリウム系研磨剤の平均粒子径が０．５μｍ以下である前項１～６のいずれか１に記載のガラス製品の製造方法。
８．前記洗浄液中の硫酸の含有量が５５～８０質量％、過酸化水素の含有量が１～１０質量％であり、前記洗浄液の温度が７０～１００℃である前項１～７のいずれか１に記載のガラス製品の製造方法。
９．前記洗浄工程の後に、コロイダルシリカ砥粒を含むスラリーを用いてガラスを研磨する仕上げ研磨工程を含む前項１～８のいずれか１に記載のガラス製品の製造方法。
１０．コロイダルシリカ砥粒の平均粒径が１０～５０ｎｍである前項９に記載のガラス製品の製造方法。
１１．前記コロイダルシリカ砥粒を含むスラリーのｐＨが１～６である前項９または１０に記載のガラス製品の製造方法。
１２．ガラス製品がガラス基板である前項１～１１のいずれか１に記載のガラス製品の製造方法。
１３．ガラス基板が情報記録媒体用ガラス基板である前項１２に記載のガラス製品の製造方法。
１４．前項１～１３のいずれか１に記載のガラス製品の製造方法によって磁気ディスク用ガラス基板を製造し、当該磁気ディスク用ガラス基板の主表面に磁気記録層を形成することを特徴とする磁気ディスクの製造方法。 That is, the present invention is as follows.
1. A method for producing a glass product, comprising: a polishing step of polishing a glass using a cerium-based abrasive; and a cleaning step of cleaning the glass using a cleaning liquid containing heated sulfuric acid and hydrogen peroxide. A method for producing a glass product, wherein the cerium-based abrasive is a cerium-based abrasive that does not contain LaOF crystals.
2. 2. The method for producing a glass product according to 1 above, wherein the cerium abrasive contains lanthanum.
3. 3. The method for producing a glass product according to item 2, wherein the cerium-based abrasive contains 20 to 40% by mass of lanthanum as La 2 O 3 .
4). 4. The method for producing a glass product according to any one of items 1 to 3, wherein the cerium-based abrasive contains fluorine.
5. 5. The method for producing a glass product according to 4 above, wherein the fluorine content in the cerium-based abrasive is more than 1% by mass.
6). Any of the preceding items 1 to 5, wherein the cerium-based abrasive contains Ce x La 1-x O y F 2-y having a fluorite structure (x is 0.5 or more and less than 1, y is 1.7 to 2) The manufacturing method of the glass product of Claim 1.
7). 7. The method for producing a glass product according to any one of items 1 to 6, wherein the cerium-based abrasive has an average particle size of 0.5 μm or less.
8). Any one of the preceding items 1 to 7 wherein the sulfuric acid content in the cleaning liquid is 55 to 80% by mass, the hydrogen peroxide content is 1 to 10% by mass, and the temperature of the cleaning liquid is 70 to 100 ° C. The manufacturing method of the glass product of description.
9. 9. The method for producing a glass product according to any one of items 1 to 8, further comprising a finish polishing step of polishing the glass with a slurry containing colloidal silica abrasive grains after the cleaning step.
10. 10. The method for producing a glass product according to 9 above, wherein the colloidal silica abrasive has an average particle size of 10 to 50 nm.
11. 11. The method for producing a glass product according to 9 or 10 above, wherein the slurry containing the colloidal silica abrasive has a pH of 1 to 6.
12 12. The method for producing a glass product according to any one of 1 to 11 above, wherein the glass product is a glass substrate.
13. 13. The method for producing a glass product according to 12 above, wherein the glass substrate is a glass substrate for an information recording medium.
14 A magnetic disk glass substrate is manufactured by the glass product manufacturing method according to any one of items 1 to 13, and a magnetic recording layer is formed on a main surface of the magnetic disk glass substrate. Production method.
　本発明のガラス製品の製造方法によれば、ＬａＯＦ結晶を含まないセリウム系研磨剤でガラスを研磨した後、加熱した硫酸と過酸化水素水とを含む洗浄剤を用いてガラスを洗浄することにより、ガラスへのセリウム系研磨剤の付着を効果的に抑制することができるとともにガラスの面荒れを防ぎ、平坦性に優れたガラス製品を得ることができる。 According to the method for producing a glass product of the present invention, after polishing glass with a cerium-based abrasive not containing LaOF crystals, the glass is washed with a detergent containing heated sulfuric acid and hydrogen peroxide. Further, the adhesion of the cerium-based abrasive to the glass can be effectively suppressed, and the glass surface can be prevented from being rough and a glass product excellent in flatness can be obtained.
　また、従来のガラス製品の製造方法では、セリウム系研磨剤を用いてガラスを研磨する工程の後に純水等による予備洗浄工程によりセリウム系研磨剤をガラスから除去した後に、加熱した硫酸と過酸化水素水とを含む洗浄剤を用いてガラスを洗浄する。 In addition, in the conventional glass product manufacturing method, after removing the cerium-based abrasive from the glass by a pre-cleaning step using pure water after the step of polishing the glass using the cerium-based abrasive, heated sulfuric acid and peroxide The glass is cleaned using a cleaning agent containing hydrogen water.
　ここで、本発明のガラス製品の製造方法によれば、セリウム系研磨剤を用いてガラスを研磨する研磨工程の後に、純水等による予備洗浄工程を経ることなく、該研磨工程に引き続いて加熱した硫酸と過酸化水素水とを含む洗浄剤を用いてガラスを洗浄した場合にも、ガラスの面荒れを防いで平坦性を得ることができるため、生産効率の観点からも優れている。 Here, according to the method for producing a glass product of the present invention, after the polishing step of polishing the glass using a cerium-based abrasive, heating is performed following the polishing step without passing through a preliminary cleaning step with pure water or the like. Even when the glass is cleaned using a cleaning agent containing sulfuric acid and hydrogen peroxide solution, the glass can be prevented from roughing and flatness can be obtained, which is also excellent from the viewpoint of production efficiency.
　また、本発明のガラス製品の製造方法によれば、酸によるダメージに起因する主表面の面荒れがないかほとんどなく、平坦性も良好であり、今後求められる高記録容量化にも十分に対応可能な磁気ディスク用ガラス基板が得られる。 In addition, according to the method for producing a glass product of the present invention, there is little or no surface roughness of the main surface due to acid damage, the flatness is good, and the high recording capacity required in the future is adequate. A possible magnetic disk glass substrate is obtained.
図１は、Ｘ線回折法により解析したセリウム系研磨剤の結晶相を示す。FIG. 1 shows a crystal phase of a cerium-based abrasive analyzed by an X-ray diffraction method. 図２（ａ）は、ＬａＯＦ結晶を含むセリウム系研磨剤を用いてガラスを研磨した後に、加熱した硫酸と過酸化水素水とを含む洗浄剤によりガラスを洗浄することにより、ガラスに面荒れが生じる機構を説明する図である。図２（ｂ）は、ＬａＯＦ結晶を含まないセリウム系研磨剤を用いてガラスを研磨した後に、加熱した硫酸と過酸化水素水とを含む洗浄剤によりガラスを洗浄することにより、ガラスに面荒れが生じないことを説明する図である。FIG. 2 (a) shows that after polishing the glass with a cerium-based abrasive containing LaOF crystals, the glass is cleaned with a cleaning agent containing heated sulfuric acid and hydrogen peroxide solution. It is a figure explaining the mechanism which arises. FIG. 2B shows that the glass is roughened by polishing the glass with a cerium-based abrasive containing no LaOF crystal and then washing the glass with a detergent containing heated sulfuric acid and hydrogen peroxide. It is a figure explaining that does not arise. 図３は、Ｘ線回折法により解析した、実施例１で用いたセリウム系研磨剤の結晶相を示す。FIG. 3 shows the crystal phase of the cerium-based abrasive used in Example 1 analyzed by the X-ray diffraction method. 図４は、Ｘ線回折法により解析した、実施例２で用いたセリウム系研磨剤の結晶相を示す。FIG. 4 shows the crystal phase of the cerium-based abrasive used in Example 2, analyzed by the X-ray diffraction method. 図５は、Ｘ線回折法により解析した、実施例３で用いたセリウム系研磨剤の結晶相を示す。FIG. 5 shows the crystal phase of the cerium-based abrasive used in Example 3, analyzed by X-ray diffraction. 図６は、Ｘ線回折法により解析した、比較例１で用いたセリウム系研磨剤の結晶相を示す。FIG. 6 shows the crystal phase of the cerium-based abrasive used in Comparative Example 1 analyzed by the X-ray diffraction method. 図７は、Ｘ線回折法により解析した、比較例２で用いたセリウム系研磨剤の結晶相を示す。FIG. 7 shows the crystal phase of the cerium-based abrasive used in Comparative Example 2 analyzed by the X-ray diffraction method. 図８は、Ｘ線回折法により解析した、比較例３で用いたセリウム系研磨剤の結晶相を示す。FIG. 8 shows the crystal phase of the cerium-based abrasive used in Comparative Example 3, analyzed by X-ray diffraction. 白色干渉法で観察した、ガラス基板の面荒れを示す図である（実施例１～３、比較例１～３）。FIG. 3 is a diagram showing surface roughness of a glass substrate observed by a white interference method (Examples 1 to 3, Comparative Examples 1 to 3).
　本発明者らは、加熱した硫酸および過酸化水素水を含む洗浄液をガラスの最終研磨工程後の洗浄に使用したときにガラスに大きな面荒れが起こる現象を調べたところ、ガラス面にセリウム系研磨剤が付着した場合にこの洗浄を行うと、その結果ガラス面に部分的な面荒れが発生することを見出した。ここで、加熱した硫酸および過酸化水素水を含む洗浄液を用いる洗浄とは、４５℃以上に加熱した硫酸および過酸化水素水を含む洗浄液による洗浄をいい、その温度は通常６０℃以上、典型的には７０℃以上である。 The present inventors investigated the phenomenon that a large surface roughness occurs in the glass when a cleaning solution containing heated sulfuric acid and hydrogen peroxide water is used for cleaning after the final polishing step of the glass. It has been found that when this cleaning is performed when an agent is attached, partial surface roughness occurs on the glass surface. Here, cleaning using a cleaning solution containing heated sulfuric acid and hydrogen peroxide water refers to cleaning with a cleaning solution containing sulfuric acid and hydrogen peroxide solution heated to 45 ° C. or higher, and the temperature is typically 60 ° C. or higher. Is 70 ° C. or higher.
　前記面荒れの原因を検討するため、種々のセリウム系研磨剤にガラスを浸漬後、乾燥させて水洗せずに、表面の付着物を加熱した硫酸および過酸化水素水を含む洗浄液により洗浄した後、ＡＤＥ社製Ｏｐｔｉｆｌａｔを用いて光学的測定方法によりガラスにおける凹み欠点を観察した。凹み欠点が生じるセリウム系研磨剤についてＸ線回折法で結晶相を調べたところ、図１に示すように、凹み欠点が観察されたセリウム系研磨剤では、ホタル石型構造結晶（ＣｅｘＬａ１－ｘＯｙＦ２－ｙ）（ｘは０．５以上１未満、ｙは１．７～２）の結晶ピークとランタンのオキシフッ化物（ＬａＯＦ）の結晶ピークとが認められたのに対し、凹み欠点が観察されなかったセリウム系研磨剤においてはオキシフッ化物の結晶ピークは認められずホタル石型構造結晶の結晶ピークのみが認められた。 In order to investigate the cause of the surface roughness, after immersing the glass in various cerium-based abrasives, without drying and washing with water, the surface deposits were washed with a cleaning solution containing heated sulfuric acid and hydrogen peroxide. The dent defect in the glass was observed by an optical measurement method using Optiflat manufactured by ADE. When the crystal phase of the cerium-based abrasive in which the dent defect is generated was examined by an X-ray diffraction method, as shown in FIG. 1, the cerium-based abrasive in which the dent defect was observed had a fluorite structure crystal (Ce x La 1). -X O y F 2-y ) (x is 0.5 or more and less than 1, y is 1.7 to 2) and a lanthanum oxyfluoride (LaOF) crystal peak, In the cerium-based abrasive in which no dent defect was observed, no crystal peak of oxyfluoride was observed, and only a crystal peak of fluorite-type structural crystal was observed.
　このことから、セリア系研磨剤に含まれるＬａＯＦ結晶が凹み欠点の原因になっている事が明らかとなった。この結果から、ガラスの研磨にＬａＯＦ結晶を含まないセリア系研磨剤を使用する事で、その後に加熱した硫酸および過酸化水素水を含む洗浄液によりガラスを洗浄したとしても、凹み欠点の発生が抑制されることに想到し本発明に至った。すなわち、ＬａまたはＦを含有しないセリア系研磨剤を使用すれば凹み欠点は発生せず、またセリア研磨剤にＬａまたはＦが含まれていたとしても、例えば、ＣｅＯ２のＣｅの一部をＬａで置換されたセリア系研磨剤、ＣｅＯ２のＯの一部をＦで置換されたセリア研磨剤、または、ＬａとＦとがそれぞれＣｅとＯの一部と置換されたセリア系研磨剤であれば、凹み欠点は発生しないというアイデアを考えつくに至った。 From this, it became clear that the LaOF crystal contained in the ceria-based polishing agent is a cause of the dent. From this result, by using a ceria-based abrasive that does not contain LaOF crystals for polishing glass, the occurrence of dent defects is suppressed even if the glass is subsequently cleaned with a cleaning solution containing sulfuric acid and hydrogen peroxide. As a result, the present invention has been achieved. That is, if a ceria-based abrasive not containing La or F is used, a dent defect does not occur. Even if La or F is contained in the ceria abrasive, for example, a part of Ce in CeO 2 is La A ceria-based abrasive in which part of O in CeO 2 is replaced by F, or a ceria-based abrasive in which La and F are replaced by part of Ce and O, respectively. In the meantime, I came up with the idea that no dent defect would occur.
　セリウム系研磨剤に含まれるランタンのオキシフッ化物（ＬａＯＦ）は、次のような機構で、ガラスに面荒れが発生する原因となっていると考えられる。図２（ａ）に示すように、加熱した硫酸および過酸化水素水を含む洗浄液中にＬａＯＦが溶け、ＬａＯＦに含まれているフッ素イオン（Ｆ－）が洗浄液中のＨ＋またはＨ２Ｏと反応してフッ化水素（ＨＦ）として機能し、下記式（１）に示すようにガラスがエッチングされて、Ｈ２ＳｉＦ６が生じる。
　ＳｉＯ２＋６ＨＦ→Ｈ２ＳｉＦ６　（１） The lanthanum oxyfluoride (LaOF) contained in the cerium-based abrasive is considered to cause the surface roughness of the glass by the following mechanism. As shown in FIG. 2 (a), LaOF is dissolved in the cleaning solution containing heated sulfuric acid and hydrogen peroxide solution, and fluorine ions (F − ) contained in LaOF are mixed with H + or H 2 O in the cleaning solution. It reacts to function as hydrogen fluoride (HF), and the glass is etched as shown in the following formula (1) to produce H 2 SiF 6 .
SiO 2 + 6HF → H 2 SiF 6 (1)
　Ｈ２ＳｉＦ６は水に可溶性であるが、加熱した硫酸および過酸化水素水を含む洗浄液中は水分量が少ないため、下記式（２）により少量のＨ２Ｏと反応してＨ２ＳｉＯ３となる。Ｈ２ＳｉＯ３は酸性の洗浄液中では不溶性であるため、ガラス表面上にゲル状の付着物となり、その後のスクラブ洗浄または仕上げ研磨等によりガラスを研磨することにより、ガラスに付着したＨ２ＳｉＯ３が除去されることに伴いガラスに凹みが生じ、ガラスの面荒れが生じる。
　Ｈ２ＳｉＦ６＋Ｈ２Ｏ→Ｈ２ＳｉＯ３＋６ＨＦ　（２） Although H 2 SiF 6 is soluble in water, the amount of water in the cleaning solution containing heated sulfuric acid and hydrogen peroxide water is small, so that it reacts with a small amount of H 2 O according to the following formula (2) to form H 2 SiO 3. It becomes. Since H 2 SiO 3 is insoluble in the acidic cleaning solution, it becomes a gel-like deposit on the glass surface, and the glass is polished by subsequent scrub cleaning or finish polishing, so that the H 2 SiO 3 attached to the glass is removed. As the glass is removed, the glass is dented, and the glass becomes rough.
H 2 SiF 6 + H 2 O → H 2 SiO 3 + 6HF (2)
　一方、図２（ｂ）に示すように、セリウム系研磨剤がＬａＯＦを含まない場合、フッ素イオンが生じないため、セリウム系研磨剤を用いてガラスを研磨した後に加熱した硫酸および過酸化水素水を含む洗浄液でガラスを洗浄した場合にも、ガラスがエッチングされることがなく、ガラスの面荒れが生じにくい。 On the other hand, as shown in FIG. 2 (b), when the cerium-based abrasive does not contain LaOF, fluorine ions are not generated. Therefore, sulfuric acid and hydrogen peroxide solution heated after polishing the glass with the cerium-based abrasive Even when the glass is washed with a cleaning solution containing, the glass is not etched, and the surface of the glass is not easily roughened.
（ガラス）
　本発明におけるガラス製品は特に限定されないが、典型的には磁気ディスク用ガラス基板またはフォトマスク基板などのガラス基板である。以下では磁気ディスク用ガラス基板を例にして説明するが、本発明はこの例に限定されない。 (Glass)
The glass product in the present invention is not particularly limited, but is typically a glass substrate such as a magnetic disk glass substrate or a photomask substrate. Hereinafter, a glass substrate for a magnetic disk will be described as an example, but the present invention is not limited to this example.
　磁気ディスク用ガラス基板を製造する場合、例えば、モル％表示で、ＳｉＯ２を５５～７５％、Ａｌ２Ｏ３を５～１７％、Ｌｉ２Ｏ＋Ｎａ２Ｏ＋Ｋ２Ｏを４～２７％、ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯを０～２０％含有し、これら成分の含有量の合計が９０％以上であるガラスからなるガラス板からガラス円板を切り出す。 When manufacturing a glass substrate for a magnetic disk, for example, in mol%, SiO 2 is 55 to 75%, Al 2 O 3 is 5 to 17%, Li 2 O + Na 2 O + K 2 O is 4 to 27%, MgO + CaO + SrO + BaO. A glass disk is cut out from a glass plate made of glass containing 0 to 20% and the total content of these components being 90% or more.
　前記ガラスにおいて、ＳｉＯ２はガラスの骨格を形成する成分であり、必須である。ＳｉＯ２の含有量を５５％以上とすることにより、比重が大きくなるのを防ぎ、ガラスにキズが付きにくくなる、失透温度が上昇するのを防ぎガラスが安定になる、または耐酸性が向上する。ＳｉＯ２の含有量は、好ましくは６０％以上、より好ましくは６１％以上、特に好ましくは６２％以上、最も好ましくは６３％以上、典型的には６４％以上である。また、ＳｉＯ２の含有量を７５％以下とすることにより、ヤング率が低くなるのを防ぎ、比弾性率が向上し、熱膨張係数が小さくなるのを防ぎ、または粘性が高くなりすぎることなくガラスの溶解が容易となる。ＳｉＯ２の含有量は、好ましくは７１％以下、より好ましくは７０％以下、最も好ましくは６８％以下である。なお、ＳｉＯ２の含有量を６３モル％以上とすることにより耐酸性が低下しにくくなる。 In the glass, SiO 2 is a component that forms a glass skeleton and is essential. By making the content of SiO 2 55% or more, the specific gravity is prevented from increasing, the glass is hardly scratched, the devitrification temperature is prevented from rising, the glass is stabilized, or the acid resistance is improved. To do. The content of SiO 2 is preferably 60% or more, more preferably 61% or more, particularly preferably 62% or more, most preferably 63% or more, and typically 64% or more. In addition, by making the content of SiO 2 75% or less, the Young's modulus is prevented from being lowered, the specific elastic modulus is improved, the thermal expansion coefficient is prevented from being reduced, or the viscosity is not excessively increased. Glass can be easily melted. The content of SiO 2 is preferably 71% or less, more preferably 70% or less, and most preferably 68% or less. Incidentally, the acid resistance is hardly lowered by setting the content of SiO 2 63 mol% or more.
　Ａｌ２Ｏ３はガラスの骨格を形成し、ヤング率や比弾性率、破壊靭性を高くする成分であり、必須である。Ａｌ２Ｏ３の含有量を５％以上とすることにより、ヤング率、比弾性率、または破壊靭性が低くなるのを防ぐことができる。Ａｌ２Ｏ３の含有量は、好ましくは６％以上、より好ましくは７％以上、典型的には８％以上である。また、Ａｌ２Ｏ３の含有量を１７％以下とすることにより、熱膨張係数が小さくなるのを防ぎ、粘性が高くなりすぎることなくガラスの溶解が容易となり、または耐酸性が低下するのを防ぐ。Ａｌ２Ｏ３の含有量は、好ましくは１５％以下、より好ましくは１４％以下である。耐酸性はＡｌ２Ｏ３の含有量を、１２．５％以下とすることにより耐酸性が低下しにくくなる。 Al 2 O 3 is a component that forms a glass skeleton and increases Young's modulus, specific elastic modulus, and fracture toughness, and is essential. By setting the content of Al 2 O 3 to 5% or more, the Young's modulus, specific elastic modulus, or fracture toughness can be prevented from being lowered. The content of Al 2 O 3 is preferably 6% or more, more preferably 7% or more, and typically 8% or more. Further, by making the content of Al 2 O 3 17% or less, it is possible to prevent the coefficient of thermal expansion from becoming small, to facilitate the melting of the glass without excessively increasing the viscosity, or to reduce the acid resistance. prevent. The content of Al 2 O 3 is preferably 15% or less, more preferably 14% or less. The acid resistance is less likely to be lowered by setting the content of Al 2 O 3 to 12.5% or less.
　上記の通り、ＳｉＯ２が多くＡｌ２Ｏ３が少ないガラスは耐酸性が低下しにくい。このため、（ＳｉＯ２－Ａｌ２Ｏ３）が大きくなるとガラスの耐酸性が向上する。一方、ヤング率、比弾性率または破壊靭性などの機械特性を向上させるにはＡｌ２Ｏ３が多いことが有効であり、機械特性に優れたガラスは耐酸性が低い傾向がある。（ＳｉＯ２－Ａｌ２Ｏ３）は典型的には４８～６２％である。 As described above, the glass having a large amount of SiO 2 and a small amount of Al 2 O 3 is unlikely to deteriorate in acid resistance. For this reason, when (SiO 2 —Al 2 O 3 ) increases, the acid resistance of the glass improves. On the other hand, in order to improve mechanical properties such as Young's modulus, specific elastic modulus, or fracture toughness, it is effective that there is a large amount of Al 2 O 3 , and glass excellent in mechanical properties tends to have low acid resistance. (SiO 2 —Al 2 O 3 ) is typically 48 to 62%.
　Ｌｉ２Ｏ、Ｎａ２ＯおよびＫ２Ｏはガラスの溶解性を改善し、熱膨張係数を高くする成分であり、いずれか１成分以上を含有しなければならない。これら３成分の含有量の合計Ｒ２Ｏを４％以上とすることによりこの効果が大きくなる。３成分の含有量の合計Ｒ２Ｏは、好ましくは１３％以上、より好ましくは１５％以上、特に好ましくは１６％以上、最も好ましくは１７％以上、典型的には１８％以上である。また、３成分の含有量の合計Ｒ２Ｏを２７％以下とすることによりヤング率、比弾性率または破壊靭性が向上する、または水分との反応でアルカリが溶出しにくくなるため、好ましい。３成分の含有量の合計Ｒ２Ｏは好ましくは２５％以下、より好ましくは２４％以下、特に好ましくは２２％以下である。Ｒ２Ｏは典型的には１６～２４％である。 Li 2 O, Na 2 O and K 2 O are components that improve the solubility of the glass and increase the thermal expansion coefficient, and must contain at least one component. This effect is enhanced by setting the total R 2 O content of these three components to 4% or more. The total R 2 O content of the three components is preferably 13% or more, more preferably 15% or more, particularly preferably 16% or more, most preferably 17% or more, and typically 18% or more. Further, it is preferable that the total R 2 O content of the three components is 27% or less because Young's modulus, specific elastic modulus, or fracture toughness is improved, or alkali is hardly eluted by reaction with moisture. The total R 2 O content of the three components is preferably 25% or less, more preferably 24% or less, and particularly preferably 22% or less. R 2 O is typically 16-24%.
　また、上記アルカリ金属酸化物の中でもＬｉ２Ｏはヤング率や比弾性率、破壊靭性を高くする効果が高いため、５％以上含有させることが好ましい。より好ましくは７％以上、最も好ましくは８％以上である。 Among the above alkali metal oxides, Li 2 O is preferably contained in an amount of 5% or more because it has a high effect of increasing Young's modulus, specific elastic modulus, and fracture toughness. More preferably, it is 7% or more, and most preferably 8% or more.
　ＭｇＯ、ＣａＯ、ＳｒＯおよびＢａＯはいずれも必須ではないが、ガラスの溶解性を改善し、熱膨張係数を高くする成分であり、これら４成分の含有量の合計Ｒ’Ｏが２０％までの範囲で含有してもよい。該４成分の含有量の合計Ｒ’Ｏを２０％以下とすることにより比重が大きくなるのを防ぐ、またはガラスが傷つきにくくなる。該４成分の含有量の合計Ｒ’Ｏは、好ましくは１０％以下、より好ましくは８％以下、最も好ましくは６％以下、典型的には４％以下である。 MgO, CaO, SrO and BaO are not essential, but are components that improve the solubility of the glass and increase the thermal expansion coefficient, and the total R′O content of these four components is in the range of up to 20%. You may contain. When the total R′O of the contents of the four components is 20% or less, the specific gravity is prevented from increasing or the glass is hardly damaged. The total R′O content of the four components is preferably 10% or less, more preferably 8% or less, most preferably 6% or less, and typically 4% or less.
　また、ヤング率、比弾性率、比重、熱膨張係数、傷つきにくさや破壊靭性といった機械特性を高めるためには、ＳｉＯ２＋Ａｌ２Ｏ３＋Ｒ２Ｏ＋Ｒ’Ｏを９０％以上とすることが好ましい。ＳｉＯ２＋Ａｌ２Ｏ３＋Ｒ２Ｏ＋Ｒ’Ｏを９０％以上とすることによりこの効果が大きくなる。ＳｉＯ２＋Ａｌ２Ｏ３＋Ｒ２Ｏ＋Ｒ’Ｏは、好ましくは９３％以上、より好ましくは９５％以上、最も好ましくは９７％以上である。 In order to improve mechanical properties such as Young's modulus, specific elastic modulus, specific gravity, thermal expansion coefficient, scratch resistance and fracture toughness, SiO 2 + Al 2 O 3 + R 2 O + R′O is preferably 90% or more. This effect is enhanced by setting SiO 2 + Al 2 O 3 + R 2 O + R′O to 90% or more. SiO 2 + Al 2 O 3 + R 2 O + R′O is preferably 93% or more, more preferably 95% or more, and most preferably 97% or more.
　この例示ガラスは本質的に上記成分からなるが、本発明の目的を損なわない範囲でその他の成分を含有してもよい。 This exemplary glass consists essentially of the above components, but may contain other components as long as the object of the present invention is not impaired.
　その他の成分としては、例えば、ＴｉＯ２、ＺｒＯ２、Ｙ２Ｏ３、Ｎｂ２Ｏ５、Ｔａ２Ｏ５およびＬａ２Ｏ３はヤング率、比弾性率または破壊靭性を高くする効果がある。これらのいずれか１以上を含有する場合、合計の含有量が７％以下であることが好ましい。７％以下とすることにより、比重が大きくなるのを防ぎ、またはガラスが傷つきにくくなる。これらの成分の合計の含有量は、より好ましくは５％未満、特に好ましくは４％未満、最も好ましくは３％未満である。 As other components, for example, TiO 2 , ZrO 2 , Y 2 O 3 , Nb 2 O 5 , Ta 2 O 5 and La 2 O 3 have an effect of increasing Young's modulus, specific elastic modulus, or fracture toughness. When any one or more of these are contained, the total content is preferably 7% or less. By making it 7% or less, the specific gravity is prevented from becoming large, or the glass is hardly damaged. The total content of these components is more preferably less than 5%, particularly preferably less than 4%, most preferably less than 3%.
　Ｂ２Ｏ３はガラスの溶解性を改善し、比重を小さくし、またガラスを傷つきにくくする効果がある。これを含有する場合３％以下が好ましい。３％以下とすることによりヤング率または比弾性率が低くなるのを防ぎ、または揮散によりガラスの品質を低下させるのを防ぐことができる。Ｂ２Ｏ３の含有量は、より好ましくは２％以下、特に好ましくは１％以下、最も好ましくは０．５％以下である。 B 2 O 3 has the effects of improving the solubility of the glass, reducing the specific gravity, and making the glass difficult to damage. When it contains this, 3% or less is preferable. By setting it to 3% or less, the Young's modulus or specific elastic modulus can be prevented from being lowered, or the glass quality can be prevented from being deteriorated by volatilization. The content of B 2 O 3 is more preferably 2% or less, particularly preferably 1% or less, and most preferably 0.5% or less.
　ＳＯ３、Ｃｌ、Ａｓ２Ｏ３、Ｓｂ２Ｏ３、ＳｎＯ２およびＣｅＯ２はガラスを清澄する効果がある。これらのいずれかを含有する場合、合計で２％以下が好ましい。 SO 3 , Cl, As 2 O 3 , Sb 2 O 3 , SnO 2 and CeO 2 have the effect of clarifying the glass. When any of these is contained, the total content is preferably 2% or less.
　なお、フォトマスク基板を製造する場合、典型的には合成石英ガラスを用いる。合成石英ガラスは、例えば珪素源と酸素源とを気相で反応させてスートと呼ばれる酸化珪素からなる多孔質体を成長させ、燒結して得られる実質的に酸化珪素のみからなるガラスである。以下、再び磁気ディスク用ガラス基板を例にして説明する。 In the case of manufacturing a photomask substrate, synthetic quartz glass is typically used. Synthetic quartz glass is a glass made of substantially only silicon oxide obtained by, for example, growing a porous body made of silicon oxide called soot by reacting a silicon source and an oxygen source in a gas phase and sintering. Hereinafter, the description will be made again by taking the glass substrate for magnetic disk as an example.
　ガラス板の比重は２．６０以下であることが好ましい。ガラス板の比重を２．６０以下とすることにより、磁気ディスクドライブ回転時にモーター負荷がかかるのを防ぎ消費電力を抑えることができる、またはドライブ回転が安定化する。ガラスの比重は、好ましくは２．５５以下、より好ましくは２．５３以下、最も好ましくは２．５２以下である。 The specific gravity of the glass plate is preferably 2.60 or less. By setting the specific gravity of the glass plate to 2.60 or less, it is possible to prevent the motor load from being applied during the rotation of the magnetic disk drive and to reduce the power consumption, or to stabilize the drive rotation. The specific gravity of the glass is preferably 2.55 or less, more preferably 2.53 or less, and most preferably 2.52 or less.
　また、ガラス板の－５０～＋７０℃の範囲における熱膨張係数（平均線膨張係数）は６０×１０－７／℃以上であることが好ましい。６０×１０－７／℃以上とすることにより、金属製のドライブなど他の部材の熱膨張係数との差が小さくなり、温度変動時の応力発生による基板の割れなどが起こりにくくなる。ガラス板の－５０～＋７０℃の範囲における熱膨張係数（平均線膨張係数）は、好ましくは６２×１０－７／℃以上、より好ましくは６５×１０－７／℃以上、最も好ましくは７０×１０－７／℃以上である。 Further, the thermal expansion coefficient (average linear expansion coefficient) in the range of −50 to + 70 ° C. of the glass plate is preferably 60 × 10 −7 / ° C. or more. By setting the temperature to 60 × 10 −7 / ° C. or more, the difference from the thermal expansion coefficient of other members such as a metal drive is reduced, and cracking of the substrate due to generation of stress at the time of temperature fluctuation is less likely to occur. The thermal expansion coefficient (average linear expansion coefficient) in the range of −50 to + 70 ° C. of the glass plate is preferably 62 × 10 −7 / ° C. or more, more preferably 65 × 10 −7 / ° C. or more, and most preferably 70 ×. 10 −7 / ° C. or higher.
　さらに、ガラス板のヤング率は８０ＧＰａ以上、比弾性率は３２ＭＮｍ／ｋｇ以上であることが好ましい。ヤング率が８０ＧＰａ以上であるか比弾性率が３２ＭＮｍ／ｋｇ以上であるとドライブ回転中に反りまたはたわみが発生しにくく、高記録密度の情報記録媒体を得易い。ガラス板のヤング率は８１ＧＰａ以上かつ比弾性率が３２．５ＭＮｍ／ｋｇ以上であることがより好ましい。 Furthermore, it is preferable that the Young's modulus of the glass plate is 80 GPa or more and the specific elastic modulus is 32 MNm / kg or more. If the Young's modulus is 80 GPa or more or the specific elastic modulus is 32 MNm / kg or more, warping or deflection is unlikely to occur during drive rotation, and an information recording medium having a high recording density can be easily obtained. The Young's modulus of the glass plate is more preferably 81 GPa or more and the specific modulus is 32.5 MNm / kg or more.
　前記例示ガラスからなるガラス板は、ヤング率、比弾性率、比重、熱膨張係数、傷つきにくさまたは破壊靭性等の諸特性が優れたものとなりやすい。 The glass plate made of the above exemplary glass tends to be excellent in various properties such as Young's modulus, specific elastic modulus, specific gravity, thermal expansion coefficient, scratch resistance or fracture toughness.
　なお、ガラス板の製造方法は特に限定されず、各種方法を適用できる。例えば、通常使用される各成分の原料を目標組成となるように調合し、これをガラス溶融窯で加熱溶融する。バブリング、撹拌または清澄剤の添加等によりガラスを均質化し、周知のフロート法、プレス法、フュージョン法またはダウンドロー法などの方法により所定の厚さの板ガラスに成形し、徐冷後必要に応じて研削、研磨などの加工を行った後、所定の寸法・形状のガラス基板とする。成形法としては、特に、大量生産に適したフロート法が好ましい。また、フロート法以外の連続成形法、例えば、フュージョン法またはダウンドロー法も好ましい。 In addition, the manufacturing method of a glass plate is not specifically limited, Various methods can be applied. For example, the raw materials of each component normally used are prepared so as to have a target composition, and this is heated and melted in a glass melting kiln. Homogenize the glass by bubbling, stirring or adding a clarifying agent, etc., and forming it into a sheet glass of a predetermined thickness by a method such as the well-known float method, press method, fusion method or downdraw method, and after slow cooling, as necessary After processing such as grinding and polishing, a glass substrate having a predetermined size and shape is obtained. As the molding method, a float method suitable for mass production is particularly preferable. Further, continuous molding methods other than the float method, for example, a fusion method or a downdraw method are also preferable.
　次いで、ガラス円板の中央に円孔を開け、面取り、主表面ラッピングおよび端面鏡面研磨を順次行う。なお、主表面ラッピング工程を粗ラッピング工程と精ラッピング工程とに分け、それらの間に形状加工工程（円形ガラス板中央の孔開け、面取り、端面研磨）を設けてもよい。 Next, a circular hole is made in the center of the glass disc, and chamfering, main surface lapping and end face mirror polishing are sequentially performed. The main surface lapping step may be divided into a rough lapping step and a fine lapping step, and a shape processing step (drilling at the center of the circular glass plate, chamfering, end polishing) may be provided between them.
　また、端面鏡面研磨は、ガラス円板を積層して内周端面をセリウム系研磨剤を用いたブラシ研磨を行い、エッチング処理をしてもよいし、内周端面のブラシ研磨の代わりにそのエッチング処理された内周端面に、例えば、ポリシラザン化合物含有液をスプレー法等によって塗布し、焼成して内周端面に被膜（保護被膜）を形成してもよい。主表面ラッピングは通常、平均粒径が６～８μｍである酸化アルミニウム砥粒または酸化アルミニウム質の砥粒を用いて行う。ラッピングされた主表面は通常、３０～４０μｍ研磨されることが好ましい。 End mirror mirror polishing may be performed by laminating glass discs and brushing the inner peripheral end surface using a cerium-based abrasive and performing etching, or by etching instead of brushing the inner peripheral end surface. For example, a polysilazane compound-containing liquid may be applied to the treated inner peripheral end face by a spray method or the like, and baked to form a coating (protective coating) on the inner peripheral end face. The main surface lapping is usually performed using aluminum oxide abrasive grains having an average particle diameter of 6 to 8 μm or abrasive grains made of aluminum oxide. The lapped main surface is usually preferably polished by 30 to 40 μm.
　これらの加工において、中央に円孔を有さないガラス基板を製造する場合には当然、ガラス円板中央の孔開けおよび内周端面の鏡面研磨は不要である。 In these processes, when manufacturing a glass substrate having no circular hole in the center, naturally, it is not necessary to make a hole in the center of the glass disk and mirror polishing of the inner peripheral end face.
（研磨工程）
　本発明のガラス製品の製造方法は、セリウム系研磨剤を用いてガラス円板の主表面を研磨する研磨工程を含む。該セリウム系研磨剤はＬａＯＦ結晶を含まない研磨剤である。また、該セリウム系研磨剤はＬａＯＦ結晶のＬａの一部をＣｅで置換した結晶を含まない研磨剤であってもよい。 (Polishing process)
The manufacturing method of the glass product of this invention includes the grinding | polishing process of grind | polishing the main surface of a glass disc using a cerium type abrasive | polishing agent. The cerium-based abrasive is an abrasive that does not contain LaOF crystals. Further, the cerium-based abrasive may be an abrasive that does not contain a crystal obtained by substituting part of La of LaOF crystal with Ce.
　本発明の製造方法に用いるセリウム系研磨剤は、それがＬａを含む場合にはホタル石型構造のＣｅｘＬａ１－ｘＯｙＦ２－ｙを含むものであることが好ましい。ここで、典型的にはｘは０．５以上１未満であり、ｙは１．７～２である。なお、セリウム系研磨剤がフッ素を含む場合は、ｙは２未満である。 The cerium-based abrasive used in the production method of the present invention preferably contains Ce x La 1-x O y F 2-y having a fluorite structure when it contains La. Here, typically, x is 0.5 or more and less than 1, and y is 1.7 to 2. When the cerium-based abrasive contains fluorine, y is less than 2.
　ＬａとＦとをオキシフッ化物（ＬａＯＦ結晶）としてではなくホタル石型構造結晶として含有するセリウム系研磨剤を用いてガラスを研磨した後に、加熱した硫酸および過酸化水素水を含む洗浄液を用いて、ガラスを十分に洗浄することができる。 After polishing the glass with a cerium-based abrasive containing La and F not as oxyfluoride (LaOF crystal) but as a fluorite structure crystal, using a cleaning solution containing heated sulfuric acid and hydrogen peroxide water, Glass can be thoroughly washed.
　ガラス研磨で用いられるセリウム系研磨剤、特に磁気ディスク用ガラス基板やフォトマスク用ガラス基板の製造で用いられるセリウム系研磨剤はコスト低減の観点などから、ホタル石型構造のＣｅｘＬａ１－ｘＯｙＦ２－ｙ（ｘは０．５以上１未満、ｙは１．７～２）とＬａＯＦ結晶とを含むものが一般的である。しかしながら、加熱した硫酸および過酸化水素水を含む洗浄液を用いる製造方法においては、ＬａＯＦは加熱した硫酸および過酸化水素水を含む洗浄液に溶解して、ＬａＯＦ結晶に含まれるフッ素がフッ酸として機能してガラスがエッチングされて面荒れが発生する。この為、本発明ではＬａＯＦ結晶を含まないセリウム系研磨剤を用いる。 A cerium-based abrasive used in glass polishing, particularly a cerium-based abrasive used in the manufacture of a glass substrate for a magnetic disk or a glass substrate for a photomask, has a fluorite-type structure Ce x La 1-x from the viewpoint of cost reduction. In general, it contains O y F 2-y (x is 0.5 or more and less than 1, y is 1.7 to 2) and LaOF crystals. However, in the production method using a cleaning solution containing heated sulfuric acid and hydrogen peroxide solution, LaOF dissolves in the cleaning solution containing heated sulfuric acid and hydrogen peroxide solution, and fluorine contained in the LaOF crystal functions as hydrofluoric acid. As a result, the glass is etched and surface roughness occurs. For this reason, in the present invention, a cerium-based abrasive that does not contain LaOF crystals is used.
　本発明に用いるセリウム系研磨剤は、水等の分散媒に分散させてスラリーとして用いてもよい。スラリーにおけるセリウム系研磨剤の含有量は、１質量％以上２０質量％以下が好ましく、３質量％以上１５質量％以下がより好ましい。 The cerium-based abrasive used in the present invention may be dispersed in a dispersion medium such as water and used as a slurry. 1 mass% or more and 20 mass% or less are preferable, and, as for content of the cerium type abrasive | polishing agent in a slurry, 3 mass% or more and 15 mass% or less are more preferable.
　スラリーにおけるセリウム系研磨剤の含有量を１質量％以上とすることにより、充分な研磨レートが得られる。また、２０質量％以下とすることで、研磨中にスラリーに混入するガラス成分の影響でスラリー粘度が上昇するのを抑え、研磨レートを向上することができる。 By setting the content of the cerium-based abrasive in the slurry to 1% by mass or more, a sufficient polishing rate can be obtained. Moreover, by setting it as 20 mass% or less, it can suppress that a slurry viscosity raises by the influence of the glass component mixed in a slurry during grinding | polishing, and can improve a polishing rate.
　スラリーのために用いることができる分散媒としては、例えば、水を挙げることができる。 Examples of the dispersion medium that can be used for the slurry include water.
　スラリーには分散剤または潤滑剤としてとして界面活性剤を含有してもよい。分散剤としての界面活性剤としては、例えば、アニオン系界面活性剤、カチオン系界面活性剤、非イオン系界面活性剤および両性イオン界面活性剤等、又はそれらの組み合わせを挙げることができる。 The slurry may contain a surfactant as a dispersant or a lubricant. Examples of the surfactant as the dispersant include an anionic surfactant, a cationic surfactant, a nonionic surfactant, a zwitterionic surfactant, and the like, or a combination thereof.
　また、例えば、２リン酸ナトリウムおよびホスホン酸ナトリウムなどのリン酸系の塩、クエン酸ナトリウムなどのカルボン酸塩、並びにリグニンスルフォン酸ナトリウムおよびナフタレンスルフォン酸ナトリウムなどのスルフォン酸塩などのモノマーの塩又はこれらの組み合わせを挙げることができる。 Also, for example, phosphate salts such as sodium diphosphate and sodium phosphonate, carboxylate salts such as sodium citrate, and monomer salts such as sulfonate salts such as sodium lignin sulfonate and sodium naphthalene sulfonate, or These combinations can be mentioned.
　セリウム系研磨剤における分散剤の含有量は砥粒に対して０．５～２質量％であることが好ましい。また、潤滑剤としての界面活性剤としては、例えば、アルキレンジオールをはじめとする非泡性の界面活性剤が挙げられる。セリウム系研磨剤における界面活性剤の含有量は０．０１～１質量％であることが好ましい。 The content of the dispersant in the cerium-based abrasive is preferably 0.5 to 2% by mass with respect to the abrasive grains. Examples of the surfactant as the lubricant include non-foaming surfactants such as alkylene diol. The content of the surfactant in the cerium-based abrasive is preferably 0.01 to 1% by mass.
　セリウム系研磨剤の平均粒子径は、ガラス製品の製造工程におけるガラスの洗浄時間が通常５～２０分であることを考慮すると、０．１μｍ以上０．５μｍ以下であることが好ましい。セリウム系研磨剤の平均粒子径はレーザー散乱を用いて測定する。この測定の場合、充分に分散したスラリーでの状態で測定できるように、上記分散剤のいずれかを研磨剤に対して１質量％程度混ぜて測定することが好ましい。 The average particle size of the cerium-based abrasive is preferably 0.1 μm or more and 0.5 μm or less considering that the glass cleaning time in the glass product manufacturing process is usually 5 to 20 minutes. The average particle size of the cerium-based abrasive is measured using laser scattering. In the case of this measurement, it is preferable to measure by mixing about 1% by mass of any of the above dispersants with respect to the abrasive so that measurement can be performed in a sufficiently dispersed slurry.
　セリウム系研磨剤の平均粒子径を０．１μｍ以上とすることにより充分な研磨レートを得ることできる。また、セリウム系研磨剤の平均粒子径を０．５μｍ以下とすることにより、ガラスと接触している面積が小さく、表層が少し溶けるだけでガラスからはがれやすくなるため、洗浄液へのセリウム系研磨剤の溶出量が十分となり、洗浄性を向上することができる。 A sufficient polishing rate can be obtained by setting the average particle diameter of the cerium-based abrasive to 0.1 μm or more. Also, by setting the average particle size of the cerium-based abrasive to 0.5 μm or less, the area in contact with the glass is small, and the surface layer is only slightly melted so that it can be easily peeled off from the glass. The amount of elution is sufficient, and the washability can be improved.
　本発明に用いるセリウム系研磨剤はフッ素を含有したとしても、ＬａＯＦ結晶を含まないため、加熱した硫酸および過酸化水素水を含む洗浄液を用いて洗浄する際にＬａＯＦ結晶に含まれるフッ素がフッ酸として機能することがなく、ガラスがエッチングされて面荒れが発生するのを防ぐことができる。 Even if the cerium-based abrasive used in the present invention contains fluorine, it does not contain LaOF crystals. Therefore, when cleaning is performed using a cleaning solution containing heated sulfuric acid and hydrogen peroxide, fluorine contained in LaOF crystals is hydrofluoric acid. It is possible to prevent the glass from being etched and causing surface roughness.
　本発明に用いるセリウム系研磨剤はフッ素を含む場合であってもその含有量は４質量％以下であることが好ましく、３質量％以下であることがより好ましく、０．１質量％以下であることが特に好ましい。また、下記効果の観点からはフッ素含有量は１質量％超であることが好ましい。フッ素はＣｅＯ２結晶の表面の酸素と置換した場合、セリウムの価数を下げる効果、すなわち、化学研磨力を向上させる効果があると考えられている。しかしＣｅＯ２結晶の表面の一部の酸素を置換するだけでそのような効果が得られるので、セリウム系研磨剤におけるフッ素の含有量は４質量％以下であることが好ましい。また、セリウム系研磨剤におけるフッ素の含有量を１質量％超とすることにより、砥粒表面のセリウムの価数が３価の状態を取りやすくなり、ガラス表面のＳｉ－Ｏ結合が弱められ研磨されやすくなる。 Even if the cerium-based abrasive used in the present invention contains fluorine, its content is preferably 4% by mass or less, more preferably 3% by mass or less, and 0.1% by mass or less. It is particularly preferred. From the viewpoint of the following effects, the fluorine content is preferably more than 1% by mass. Fluorine is considered to have an effect of lowering the valence of cerium, that is, an effect of improving chemical polishing power, when substituted with oxygen on the surface of the CeO 2 crystal. However, since such an effect can be obtained only by substituting part of oxygen on the surface of the CeO 2 crystal, the content of fluorine in the cerium-based abrasive is preferably 4% by mass or less. Also, by setting the fluorine content in the cerium-based abrasive to more than 1% by mass, the cerium valence on the surface of the abrasive grains can be easily taken to be trivalent, and the Si—O bond on the glass surface is weakened and polished. It becomes easy to be done.
　本発明に用いるセリウム系研磨剤としては、ランタンを含むセリウム系研磨剤が挙げられる。セリウム系研磨剤に含まれるランタンは、ＣｅＸＬａ１－ＸＯｙＦ２－Ｙ（ｘは０．５以上１未満、ｙは１．７～２）であることが好ましい。セリウム系研磨剤はＬａ２Ｏ３としてランタンを２０～４０質量％含有することが好ましく、３０～４０質量％含有することがより好ましい。セリウム系研磨剤におけるＬａ２Ｏ３の含有量をこの範囲とすることで、高い研磨レートが得られる。 Examples of the cerium-based abrasive used in the present invention include cerium-based abrasives containing lanthanum. The lanthanum contained in the cerium-based abrasive is preferably Ce X La 1-X O y F 2-Y (x is 0.5 or more and less than 1, y is 1.7 to 2). The cerium-based abrasive preferably contains 20 to 40% by mass, more preferably 30 to 40% by mass of lanthanum as La 2 O 3 . By setting the content of La 2 O 3 in the cerium-based abrasive within this range, a high polishing rate can be obtained.
　本発明における研磨の方法は特に限定されないが、例えば、ガラスと研磨布とを接触させ、セリウム系研磨剤を供給しながら、研磨布とガラスとを相対的に移動させて、ガラスを鏡面状に研磨することが好ましい。研磨布としては、例えば、ウレタン製研磨パッドを用いることができる。 The polishing method in the present invention is not particularly limited. For example, the glass and the polishing cloth are brought into contact with each other, and the polishing cloth and the glass are relatively moved while supplying the cerium-based abrasive, so that the glass is mirror-like. It is preferable to polish. As the polishing cloth, for example, a urethane polishing pad can be used.
　研磨工程は、具体的には、例えば、三次元表面構造解析装置［例えばＡＤＥ社製Ｏｐｔｉ－ｆｌａｔ（商品名）］を用いて波長領域がλ≦５ｍｍの条件で測定されたうねり（Ｗａ）が１ｎｍ以下となるように研磨することが好ましい。また、研磨による板厚の減少量（研磨量）は、典型的には５～１５μｍであることが好ましい。 Specifically, in the polishing step, for example, a waviness (Wa) measured using a three-dimensional surface structure analyzer [for example, ADE Opti-flat (trade name)] under a condition where the wavelength region is λ ≦ 5 mm. It is preferable to polish so that it may become 1 nm or less. Further, the reduction amount of the plate thickness due to polishing (polishing amount) is typically preferably 5 to 15 μm.
　研磨工程は、１回の研磨で行ってもよいし、平均粒子径の異なるセリウム系研磨剤を用いて２回以上実施してもよい。なお、２回以上行う場合は、最終のセリウム研磨以外は、セリウム系研磨剤は公知のＬａＯＦ結晶を含むものでもよい。 The polishing step may be performed once, or may be performed twice or more using a cerium-based abrasive having different average particle diameters. In addition, when performing twice or more, a cerium type abrasive | polishing agent may contain a well-known LaOF crystal | crystallization other than final cerium grinding | polishing.
　また、本発明における研磨工程はラッピング工程で発生したキズ除去を目的とする酸化セリウム主表面研磨工程を含むが、それに限らず、ラッピング工程後に酸化セリウムによる端面鏡面研磨が行われればそれも含む。 In addition, the polishing step in the present invention includes a cerium oxide main surface polishing step for removing scratches generated in the lapping step, but is not limited to this, and includes end surface mirror polishing with cerium oxide after the lapping step.
（予備洗浄）
　研磨が行われたガラス円板について予備洗浄を行ってもよい。予備洗浄は、例えば、純水での浸漬洗浄、アルカリ洗浄剤での超音波洗浄、純水でのリンスをこの順序で行う。純水での浸漬洗浄または純水でのリンスにおいては、超音波洗浄を併用したり、流水またはシャワー水を用いてもよい。 (Preliminary cleaning)
You may perform preliminary washing | cleaning about the glass disc in which grinding | polishing was performed. In the preliminary cleaning, for example, immersion cleaning with pure water, ultrasonic cleaning with an alkaline cleaning agent, and rinsing with pure water are performed in this order. In immersion cleaning with pure water or rinsing with pure water, ultrasonic cleaning may be used in combination, or running water or shower water may be used.
　なお、本発明によれば、ＬａＯＦ結晶を含まないセリウム系研磨剤を用いることにより、研磨が行われたガラス円板を予備洗浄することなく、加熱した硫酸および過酸化水素水を含む洗浄液により洗浄した場合にも凹み欠点が生じるのを抑え、面荒れを低減させたガラス製品を得ることができる。 According to the present invention, by using a cerium-based abrasive that does not contain LaOF crystals, the glass disc that has been polished is cleaned with a cleaning solution containing heated sulfuric acid and hydrogen peroxide without pre-cleaning. In such a case, it is possible to obtain a glass product that suppresses the occurrence of a dent defect and reduces surface roughness.
（乾燥工程）
　研磨が行われたガラス円板を乾燥させてもよい。乾燥は、例えば、スピン乾燥することにより、行う。 (Drying process)
The polished glass disc may be dried. Drying is performed, for example, by spin drying.
（洗浄工程）
　本発明のガラス製品の製造方法は、加熱した硫酸および過酸化水素水を含む洗浄液を用いてガラスに付着したセリウム系研磨剤を洗浄する工程を含む（以下、この洗浄を本発明における洗浄、この洗浄液を本発明に用いる洗浄液ともいう。）。 (Washing process)
The method for producing a glass product of the present invention includes a step of cleaning the cerium-based abrasive adhering to the glass using a cleaning liquid containing heated sulfuric acid and hydrogen peroxide (hereinafter, this cleaning is referred to as cleaning in the present invention, this The cleaning liquid is also referred to as a cleaning liquid used in the present invention).
　本発明に用いる洗浄液における硫酸の含有量は５５～８０質量％であることが好ましく、より好ましくは６０質量％以上、更に好ましくは６５質量％以上である。硫酸の含有量を５５質量％以上とすることにより、ガラス円板に付着したセリウム系研磨剤が溶解されずに残留するのを防ぐことができる。また、硫酸の含有量を８０質量％以下とすることにより、リーチングによる面荒れを防ぎ、目的とする平坦性を得易く、洗浄装置に汎用的に使用される樹脂製冶具が酸化・分解するのを防ぐことができる。 The content of sulfuric acid in the cleaning liquid used in the present invention is preferably 55 to 80% by mass, more preferably 60% by mass or more, and still more preferably 65% by mass or more. By making content of sulfuric acid 55 mass% or more, it can prevent that the cerium type abrasive | polishing agent adhering to the glass disc remains without melt | dissolving. In addition, by making the sulfuric acid content 80% by mass or less, surface roughness due to leaching can be prevented, the intended flatness can be easily obtained, and resin jigs that are generally used in cleaning devices are oxidized and decomposed. Can be prevented.
　本発明に用いる洗浄液における過酸化水素の含有量は１～１０質量％であることが好ましく、より好ましくは２質量％以上、更に好ましくは４質量％以上である。過酸化水素の含有量を１質量％以上とすることにより、ガラス円板に付着したセリウム系研磨剤が溶解されずに残留するのを防ぐことができる。また、過酸化水素の含有量を１０質量％以下とすることにより、リーチングによる面荒れを防ぎ、目的とする平坦性を得易く、洗浄装置に汎用的に使用される樹脂製冶具が酸化・分解するのを防ぐことができる。 The content of hydrogen peroxide in the cleaning liquid used in the present invention is preferably 1 to 10% by mass, more preferably 2% by mass or more, and further preferably 4% by mass or more. By setting the content of hydrogen peroxide to 1% by mass or more, it is possible to prevent the cerium-based abrasive adhered to the glass disk from remaining undissolved. In addition, by setting the hydrogen peroxide content to 10% by mass or less, surface roughness due to leaching can be prevented, and the desired flatness can be easily obtained. Can be prevented.
　本発明に用いる洗浄液は、温度が７０～１００℃であることが好ましい。また、７５℃～９０℃であることがより好ましい。洗浄液の温度を７０℃以上とすることにより、セリウム系研磨剤がガラスに残りにくくなる。また、洗浄液の温度を１００℃以下とすることにより、過酸化水素の分解を抑え、洗浄液組成が変化するのを防ぐことができる。 The temperature of the cleaning liquid used in the present invention is preferably 70 to 100 ° C. Further, it is more preferably 75 ° C. to 90 ° C. By setting the temperature of the cleaning liquid to 70 ° C. or higher, the cerium-based abrasive is less likely to remain on the glass. In addition, by setting the temperature of the cleaning liquid to 100 ° C. or lower, it is possible to suppress the decomposition of hydrogen peroxide and prevent the cleaning liquid composition from changing.
　本発明に用いる洗浄液におけるその他の成分は通常は水であることが好ましい。すなわち本発明に用いる洗浄液は通常水溶液であることが好ましく、その場合でも本発明の目的を損なわない範囲で水以外の成分を含んでもよい。水としては、例えば、脱イオン水、超純水、電荷イオン水、水素水およびオゾン水などが挙げられる。 The other component in the cleaning liquid used in the present invention is usually preferably water. That is, it is preferable that the cleaning liquid used in the present invention is usually an aqueous solution, and even in that case, it may contain components other than water as long as the object of the present invention is not impaired. Examples of water include deionized water, ultrapure water, charged ion water, hydrogen water, and ozone water.
　また、本発明において洗浄工程の時間は典型的には５分間またはそれ以上であることが好ましく、通常は３０分間以下で洗浄目的を達することができる。 In the present invention, it is preferable that the time for the washing step is typically 5 minutes or longer, and usually the washing purpose can be achieved in 30 minutes or less.
　本発明に用いる洗浄液には、液の表面張力を下げる目的で、界面活性剤を含んでもよい。界面活性剤としては、例えば、ポリアクリル酸塩、ポリマレイン酸塩およびポリイタコン酸塩などのカルボン酸塩、並びにアルキルスルフォン酸塩などのスルフォン酸などが挙げられる。洗浄液における界面活性剤の含有量は、特に限定されないが、１質量％以下とすることが好ましい。 The cleaning liquid used in the present invention may contain a surfactant for the purpose of reducing the surface tension of the liquid. Examples of the surfactant include carboxylates such as polyacrylates, polymaleates and polyitaconates, and sulfonic acids such as alkyl sulfonates. The content of the surfactant in the cleaning liquid is not particularly limited, but is preferably 1% by mass or less.
　洗浄工程では、前記洗浄液をガラスに直接接触させて洗浄することが好ましい。洗浄液をガラスに直接接触させる方法としては、例えば、洗浄液を洗浄槽に満たしてその中にガラスを入れるディップ式洗浄、ノズルからガラスに洗浄液を噴射する方法、およびポリビニルアルコール製のスポンジを用いるスクラブ洗浄などが挙げられる。 In the cleaning step, it is preferable to perform cleaning by bringing the cleaning liquid into direct contact with glass. Examples of the method of bringing the cleaning liquid into direct contact with the glass include, for example, dip-type cleaning in which the cleaning liquid is filled in a cleaning tank, and glass is placed therein, a method of spraying the cleaning liquid from the nozzle onto the glass, and scrub cleaning using a sponge made of polyvinyl alcohol Etc.
　本発明に用いる洗浄液は、これらのいずれの方法にも適応できるが、より効率的な洗浄ができることから、ディップ式洗浄が好ましい。ディップ式の場合、洗浄液にガラスを浸漬させる時間を２分以上とすることが好ましい。また、接触中に超音波洗浄を併用することがより好ましい。 The cleaning liquid used in the present invention can be applied to any of these methods, but dip-type cleaning is preferred because more efficient cleaning can be performed. In the case of the dip type, it is preferable that the time for immersing the glass in the cleaning liquid is 2 minutes or more. Moreover, it is more preferable to use ultrasonic cleaning together during the contact.
（仕上げ研磨工程）
　仕上げ研磨工程では、通常、コロイダルシリカ砥粒を含むスラリーを用いて最終研磨を行う。仕上げ研磨工程では、通常、平均粒径が１０～５０ｎｍのコロイダルシリカ砥粒を含むスラリーを用いて研磨されるが、その前に平均粒径が５０ｎｍ超１００ｎｍ以下のコロイダルシリカ砥粒を含むスラリーを用いて前研磨してもよい。また、コロイダルシリカ砥粒を含むスラリーでの研磨の前または後に化学強化を行ってもよい。 (Finishing polishing process)
In the final polishing step, the final polishing is usually performed using a slurry containing colloidal silica abrasive grains. In the final polishing step, polishing is usually performed using a slurry containing colloidal silica abrasive grains having an average particle diameter of 10 to 50 nm, but before that, a slurry containing colloidal silica abrasive grains having an average particle diameter of more than 50 nm and 100 nm or less is used. It may be used for prepolishing. Further, chemical strengthening may be performed before or after polishing with a slurry containing colloidal silica abrasive grains.
　コロイダルシリカ砥粒を含むスラリーによる研磨では、水ガラスを原料とするコロイダルシリカでは、一般的に中性領域においてゲル化が進行しやすいため、ｐＨが１～６もしくは２～６で行うことが好ましい。 In polishing with a slurry containing colloidal silica abrasive grains, colloidal silica using water glass as a raw material generally tends to undergo gelation in a neutral region, and therefore it is preferable to carry out at a pH of 1 to 6 or 2 to 6. .
　ｐＨ調整剤としては、酸であれば無機酸または有機酸が用いられる。無機酸としては、例えば、塩酸、硝酸、硫酸、燐酸、ポリ燐酸およびアミド硫酸等が挙げられる。また、有機酸としては、例えば、カルボン酸、有機燐酸、アミノ酸等が挙げられる。カルボン酸としては、例えば、酢酸、グリコール酸およびアスコルビン酸等の一価カルボン酸、蓚酸および酒石酸等の二価カルボン酸、並びにクエン酸等の三価カルボン酸が挙げられる。 As the pH adjuster, an inorganic acid or an organic acid is used as long as it is an acid. Examples of inorganic acids include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, polyphosphoric acid, amidosulfuric acid, and the like. Moreover, as an organic acid, carboxylic acid, organic phosphoric acid, an amino acid etc. are mentioned, for example. Examples of the carboxylic acid include monovalent carboxylic acids such as acetic acid, glycolic acid and ascorbic acid, divalent carboxylic acids such as succinic acid and tartaric acid, and trivalent carboxylic acids such as citric acid.
　特にｐＨを１～３とすることが好ましく、その場合は無機酸を用いることが好ましい。また、ｐＨ３超においては、カルボン酸を用いるとコロイダルシリカ砥粒のゲル化を抑制できるため好ましい。さらに、スラリーにアニオンもしくはノニオン界面活性剤を添加してもよい。 In particular, the pH is preferably 1 to 3, in which case it is preferable to use an inorganic acid. In addition, when the pH is higher than 3, it is preferable to use carboxylic acid because gelation of colloidal silica abrasive grains can be suppressed. Further, an anionic or nonionic surfactant may be added to the slurry.
　研磨具はスエードパッドであることが好ましい。このスエードパッドは発泡樹脂層を有し、そのショアＡ硬度が２０°以上６０°以下であり、密度が０．２～０．８ｇ／ｃｍ３であることが好ましい。 The polishing tool is preferably a suede pad. This suede pad has a foamed resin layer, preferably has a Shore A hardness of 20 ° to 60 °, and a density of 0.2 to 0.8 g / cm 3 .
　仕上げ研磨工程によりガラス円板は、主表面の二乗平均粗さ（Ｒｍｓ）が好ましくは０．１５ｎｍ以下、より好ましくは０．１３ｎｍ以下の平坦性を有するように研磨されることが好ましい。この研磨における板厚の減少量（研磨量）は、典型的には０．５～２μｍである。 The glass disk is preferably polished by the final polishing step so that the root mean square roughness (Rms) of the main surface is preferably 0.15 nm or less, more preferably 0.13 nm or less. A reduction amount (polishing amount) of the plate thickness in this polishing is typically 0.5 to 2 μm.
　仕上げ研磨工程の後、コロダルシリカ砥粒を除去するために洗浄を行う。この洗浄工程では、少なくとも１回はｐＨ１０以上のアルカリ性洗浄剤による洗浄を行うことが好ましい。洗浄方法は、ガラス円板を浸漬して超音波振動を加えてもよいし、スクラブ洗浄を用いてもよい。また、両方を組み合わせてもよい。さらに、洗浄の前後に、純水による浸漬工程やリンス工程を行うことが好ましい。 After the finish polishing process, cleaning is performed to remove the colloidal silica abrasive grains. In this cleaning step, it is preferable to perform cleaning with an alkaline cleaning agent having a pH of 10 or more at least once. As a cleaning method, ultrasonic vibration may be applied by immersing a glass disk, or scrub cleaning may be used. Moreover, you may combine both. Furthermore, it is preferable to perform an immersion step and a rinse step with pure water before and after cleaning.
　最終のリンス工程後にガラス円板を乾燥するが、乾燥方法としては、例えば、イソプロピルアルコール蒸気を用いる乾燥方法、スピン乾燥または真空乾燥などが用いられる。 The glass disk is dried after the final rinsing step. As a drying method, for example, a drying method using isopropyl alcohol vapor, spin drying or vacuum drying is used.
　上記一連の工程により、主表面に残留セリウム系研磨剤がなく、あるいは残留セリウム系研磨剤による問題が生じず、高度に平坦化されたガラス製品が得られる。 Through the above series of steps, there is no residual cerium-based abrasive on the main surface, or there is no problem with the residual cerium-based abrasive, and a highly flattened glass product can be obtained.
　本発明の製造方法により製造されるガラス製品は、１ｍｍ×１ｍｍ以上の大きさの凹み欠点が０個／１面以下であることが好ましい。凹み欠点の観察は実施例で後述する方法により行う。 It is preferable that the glass product manufactured by the manufacturing method of the present invention has 0 or 1 surface or less concave defects having a size of 1 mm × 1 mm or more. The observation of the dent defect is performed by the method described later in the examples.
　本発明の製造方法により製造されるガラス製品としては、例えば、磁気ディスク用ガラス基板、フォトマスク基板およびディスプレイ基板などのガラス基板、並びにその他にＣＣＤ向けブルーフィルタガラスおよびカバーガラスなどが挙げられる。本発明の製造方法により製造される磁気ディスク用ガラス基板の主表面に磁気記録層を形成することにより磁気ディスクを製造することができる。本発明の製造方法により得られる高度に平坦化されたガラス基板の主表面に磁気記録層を形成した磁気ディスクによれば、高密度記録が可能になる。 Examples of glass products produced by the production method of the present invention include glass substrates for magnetic disks, glass substrates such as photomask substrates and display substrates, and blue filter glass and cover glass for CCDs. A magnetic disk can be manufactured by forming a magnetic recording layer on the main surface of a glass substrate for a magnetic disk manufactured by the manufacturing method of the present invention. According to the magnetic disk in which the magnetic recording layer is formed on the main surface of the highly flattened glass substrate obtained by the manufacturing method of the present invention, high density recording is possible.
　以下に本発明の実施例について具体的に説明するが、本発明はこれらに限定されない。 Examples of the present invention will be specifically described below, but the present invention is not limited to these.
　モル％表示組成が概略、ＳｉＯ２：６２％、Ａｌ２Ｏ３：１３％、ＭｇＯ：３％、ＴｉＯ２：１％、ＺｒＯ２：１％、Ｌｉ２Ｏ：１１％、Ｎａ２Ｏ：７％、Ｋ２Ｏ：３％、であるガラス板から外径６５ｍｍ、内径２０ｍｍ、板厚０．６３５ｍｍのドーナツ状ガラス円板５０枚を切り出し、内周面および外周面をダイヤモンド砥石を用いて研削加工し、上下主表面を酸化アルミニウム砥粒を用いてラッピングした。 Mol% composition schematic, SiO 2: 62%, Al 2 O 3: 13%, MgO: 3%, TiO 2: 1%, ZrO 2: 1%, Li 2 O: 11%, Na 2 O: 7 %, K 2 O: 3%, 50 donut-shaped glass discs having an outer diameter of 65 mm, an inner diameter of 20 mm, and a thickness of 0.635 mm are cut out and the inner and outer peripheral surfaces are ground using a diamond grindstone. The upper and lower main surfaces were lapped using aluminum oxide abrasive grains.
　次に、内外周の端面について幅０．１５ｍｍ、角度４５°の面取り部を設ける面取り加工を行った。面取り加工後、内外周の端面について、研磨材としてセリウム系研磨剤を含むスラリーを用い、研磨具としてブラシを用いて、ブラシ研磨により鏡面加工を行った。研磨量は、半径方向の除去量で３０μｍであった。 Next, chamfering was performed on the inner and outer end faces by providing a chamfered portion having a width of 0.15 mm and an angle of 45 °. After the chamfering, the end surfaces of the inner and outer periphery were mirror-finished by brush polishing using a slurry containing a cerium-based abrasive as an abrasive and using a brush as an abrasive. The removal amount in the radial direction was 30 μm.
　鏡面加工後、研磨材として表１または表２に示されるセリウム系研磨剤を含むスラリーを用い、研磨具としてウレタンパッドを用いて、両面研磨装置により上下主表面の研磨加工を行った。研磨量は、上下主表面の厚さ方向で計５μｍであった。なお、実施例２においては、セリウム系研磨剤として通常製品を精製したものを用いた。 After mirror finishing, the upper and lower main surfaces were polished by a double-side polishing apparatus using a slurry containing a cerium-based abrasive shown in Table 1 or 2 as an abrasive and a urethane pad as a polishing tool. The amount of polishing was 5 μm in total in the thickness direction of the upper and lower main surfaces. In Example 2, a product obtained by purifying a normal product as a cerium-based abrasive was used.
　なお、使用したセリウム系研磨剤のＸ線構造を理学電気社製ＲＩＮＴ２５００により観察した結果を図３～８に示す。また、表１および表２において、研磨砥粒の粒径は、日機装製ＭＴ３３００ＥＸＩＩにより測定した。 The results of observing the X-ray structure of the used cerium-based abrasive with RINT 2500 manufactured by Rigaku Corporation are shown in FIGS. In Tables 1 and 2, the particle size of the abrasive grains was measured by Nikkiso MT3300EXII.
　表１および表２において、Ｘ線回折から得られる構造が「単相」とはＩｎｔｅｒｎａｔｉｏｎａｌ　Ｃｅｎｔｒｅ　ｆｏｒ　Ｄｉｆｆｒａｃｔｉｏｎ　Ｄａｔａ（登録商標）［ＩＣＤＤ（登録商標）］が提供している粉末回折データをもとに検証した場合、蛍石型構造の酸化セリウム粒子のピーク位置と一致するか、すべてのピークが±０．５°の範囲に入っているものであることを示し、「２相以上」とはＩｎｔｅｒｎａｔｉｏｎａｌ　Ｃｅｎｔｒｅ　ｆｏｒ　Ｄｉｆｆｒａｃｔｉｏｎ　Ｄａｔａ（登録商標）［ＩＣＤＤ（登録商標）］が提供している粉末回折データをもとに検証した場合、蛍石型構造の酸化セリウム粒子のピーク位置と±５°以内で一致するピーク以外にピークがある場合であることを示す。 In Tables 1 and 2, the structure obtained from X-ray diffraction is “single phase” and verified based on powder diffraction data provided by International Center for Diffraction Data (registered trademark) [ICDD (registered trademark)]. In this case, the peak position of the fluorite-type cerium oxide particles coincides with the peak position, or all peaks are within the range of ± 0.5 °, and “two or more phases” means “International Center”. When verified based on powder diffraction data provided by for Diffraction Data (registered trademark) [ICDD (registered trademark)], the peak coincides with the peak position of cerium oxide particles having a fluorite structure within ± 5 ° This indicates that there is a peak other than.
　ガラス円板の主表面を研磨後、２時間乾燥させて、１時間７０℃で加熱した後に、７４質量％の硫酸、および１１．４質量％の過酸化水素水を含み８０℃に加熱した洗浄液で５分間浸漬させて洗浄した。 The main surface of the glass disk is polished, dried for 2 hours, heated at 70 ° C. for 1 hour, and then heated to 80 ° C. containing 74% by mass sulfuric acid and 11.4% by mass hydrogen peroxide. And soaked for 5 minutes.
　このようにして得られたガラス円板について、加熱した硫酸および過酸化水素水を含む洗浄液による洗浄前と後とでＡＤＥ社製Ｏｐｔｉｆｌａｔにより表面形状を測定した。その結果を図９に示す。図９において、Ａ面とは、ガラス円板の一方の面を示し、Ｂ面とはもう一方の面を示す。 The surface shape of the glass disk thus obtained was measured by Optiflat manufactured by ADE before and after cleaning with a cleaning liquid containing heated sulfuric acid and hydrogen peroxide. The result is shown in FIG. In FIG. 9, the A surface indicates one surface of the glass disk, and the B surface indicates the other surface.
　また、ＡＤＥ社製Ｏｐｔｉ－ｆｌａｔを用いて白色干渉法によりガラス円板両面の表面形状を観察し、１ｍｍ×１ｍｍ以上の大きさの凹みがあるものを面荒れが発生したガラス板とした。その結果を表２に示す。 Also, the surface shape of both sides of the glass disk was observed by white interference method using Opti-flat manufactured by ADE, and a glass plate with rough surface was defined as having a dent of 1 mm × 1 mm or more. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１、並びに図３～５および９に示すように、ＬａＯＦ結晶を含まない、単相の結晶構造であるセリウム系研磨剤を含むスラリーを用いてガラスを研磨した実施例１～３により得られたガラス板においては、加熱した硫酸および過酸化水素水を含む洗浄液による洗浄により面荒れが発生しなかった。 As shown in Table 1 and FIGS. 3 to 5 and 9, the glass was polished by using Examples 1 to 3 in which a slurry containing a cerium-based abrasive having a single-phase crystal structure and containing no LaOF crystals was used. The glass plate was not roughened by cleaning with a cleaning solution containing heated sulfuric acid and hydrogen peroxide.
　一方、表１、並びに図３～５および９に示すように、ＬａＯＦ結晶を含む、２相以上の結晶構造であるセリウム系研磨剤を含むスラリーを用いてガラスを研磨した比較例１～３により得られたガラス板においては、加熱した硫酸および過酸化水素水を含む洗浄液による洗浄により面荒れが発生した。 On the other hand, as shown in Table 1 and FIGS. 3 to 5 and 9, according to Comparative Examples 1 to 3 in which glass was polished using a slurry containing a cerium-based abrasive having a crystal structure of two or more phases including LaOF crystals. The obtained glass plate was roughened by cleaning with a cleaning solution containing heated sulfuric acid and hydrogen peroxide.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２に示すように、ＬａＯＦ結晶を含まない、単相の結晶構造であるセリウム系研磨剤を含むスラリーを用いてガラスを研磨した実施例４～６により得られたガラス板においては、加熱した硫酸および過酸化水素水を含む洗浄液による洗浄により凹み欠点が発生しなかった。 As shown in Table 2, the glass plates obtained in Examples 4 to 6 in which the glass was polished using a slurry containing a cerium-based abrasive having a single-phase crystal structure and containing no LaOF crystals were heated. No dent defect was generated by cleaning with a cleaning solution containing sulfuric acid and hydrogen peroxide.
　一方、表２に示すように、ＬａＯＦ結晶を含む、２相以上の結晶構造であるセリウム系研磨剤を含むスラリーを用いてガラスを研磨した比較例４～６により得られたガラス板においては、加熱した硫酸および過酸化水素水を含む洗浄液による洗浄により、凹み欠点が発生した。 On the other hand, as shown in Table 2, in the glass plates obtained by Comparative Examples 4 to 6 in which the glass was polished using a slurry containing a cerium-based abrasive having a crystal structure of two or more phases containing LaOF crystals, A dent defect was generated by cleaning with a cleaning solution containing heated sulfuric acid and hydrogen peroxide.
　これらの結果から、セリウム系研磨剤によりガラスを研磨することにより、その後に加熱した硫酸および過酸化水素水を含む洗浄液でガラスを洗浄することによる面荒れの発生の原因がセリウム系研磨剤に含まれるＬａＯＦ結晶であり、ＬａＯＦ結晶を含まないセリウム系研磨剤を用いてガラスを研磨し、その後に加熱した硫酸および過酸化水素水を含む洗浄液でガラスを洗浄することにより、凹み欠点の発生を防ぎ、面荒れを効果的に抑制し、平坦性に優れたガラスが得られることがわかった。 From these results, cerium-based abrasives contain the cause of surface roughness caused by polishing glass with a cerium-based abrasive and then cleaning the glass with a cleaning solution containing heated sulfuric acid and hydrogen peroxide. By using a cerium-based abrasive that does not contain LaOF crystals, the glass is polished, and then the glass is washed with a cleaning solution containing heated sulfuric acid and hydrogen peroxide, thereby preventing the formation of dent defects. It was found that a glass having excellent flatness can be obtained by effectively suppressing surface roughness.
　さらに、本発明の製造方法によれば、研磨工程の後に、予備洗浄工程を経ずにそのまま加熱した硫酸および過酸化水素水を含む洗浄液でガラスを洗浄したとしても、面荒れの発生を抑制できることがわかった。 Furthermore, according to the manufacturing method of the present invention, even when the glass is washed with a cleaning solution containing sulfuric acid and hydrogen peroxide water heated without undergoing a preliminary cleaning step after the polishing step, the occurrence of surface roughness can be suppressed. I understood.
　本発明を特定の態様を用いて詳細に説明したが、本発明の意図と範囲を離れることなく様々な変更および変形が可能であることは、当業者にとって明らかである。なお本出願は、２０１２年２月６日付で出願された日本特許出願（特願２０１２－０２２７５１）に基づいており、その全体が引用により援用される。 Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention. This application is based on a Japanese patent application filed on February 6, 2012 (Japanese Patent Application No. 2012-022751), which is incorporated by reference in its entirety.

Claims (14)

  1. 　セリウム系研磨剤を用いてガラスを研磨する研磨工程と、その後に、加熱した硫酸と過酸化水素水とを含む洗浄液を用いてガラスを洗浄する洗浄工程とを含むガラス製品の製造方法であって、該セリウム系研磨剤がＬａＯＦ結晶を含まないセリウム系研磨剤であるガラス製品の製造方法。 A method for producing a glass product, comprising: a polishing step of polishing a glass using a cerium-based abrasive; and a cleaning step of cleaning the glass using a cleaning liquid containing heated sulfuric acid and hydrogen peroxide. A method for producing a glass product, wherein the cerium-based abrasive is a cerium-based abrasive that does not contain LaOF crystals.
  2. 　前記セリウム系研磨剤がランタンを含む請求項１に記載のガラス製品の製造方法。 The method for producing a glass product according to claim 1, wherein the cerium-based abrasive contains lanthanum.
  3. 　前記セリウム系研磨剤がランタンをＬａ２Ｏ３として２０～４０質量％含有する請求項２に記載のガラス製品の製造方法。 The method for producing a glass product according to claim 2, wherein the cerium-based abrasive contains 20 to 40% by mass of lanthanum as La 2 O 3 .
  4. 　前記セリウム系研磨剤がフッ素を含む請求項１～３のいずれか１項に記載のガラス製品の製造方法。 The method for producing a glass product according to any one of claims 1 to 3, wherein the cerium-based abrasive contains fluorine.
  5. 　前記セリウム系研磨剤におけるフッ素の含有量が１質量％超である請求項４に記載のガラス製品の製造方法。 The method for producing a glass product according to claim 4, wherein the content of fluorine in the cerium-based abrasive is more than 1% by mass.
  6. 　前記セリウム系研磨剤がホタル石型構造のＣｅｘＬａ１－ｘＯｙＦ２－ｙ（ｘは０．５以上１未満、ｙは１．７～２）を含む、請求項１～５のいずれか１項に記載のガラス製品の製造方法。 6. The cerium-based abrasive according to claim 1 , wherein Ce x La 1-x O y F 2-y having a fluorite-type structure (x is 0.5 or more and less than 1, y is 1.7 to 2). The manufacturing method of the glass product of any one.
  7. 　前記セリウム系研磨剤の平均粒子径が０．５μｍ以下である請求項１～６のいずれか１項に記載のガラス製品の製造方法。 The method for producing a glass product according to any one of claims 1 to 6, wherein the cerium-based abrasive has an average particle size of 0.5 µm or less.
  8. 　前記洗浄液中の硫酸の含有量が５５～８０質量％、過酸化水素の含有量が１～１０質量％であり、前記洗浄液の温度が７０～１００℃である請求項１～７のいずれか１項に記載のガラス製品の製造方法。 The sulfuric acid content in the cleaning liquid is 55 to 80% by mass, the hydrogen peroxide content is 1 to 10% by mass, and the temperature of the cleaning liquid is 70 to 100 ° C. The manufacturing method of the glass product of description.
  9. 　前記洗浄工程の後に、コロイダルシリカ砥粒を含むスラリーを用いてガラスを研磨する仕上げ研磨工程を含む請求項１～８のいずれか１項に記載のガラス製品の製造方法。 The method for producing a glass product according to any one of claims 1 to 8, further comprising a finish polishing step of polishing the glass with a slurry containing colloidal silica abrasive grains after the cleaning step.
  10. 　コロイダルシリカ砥粒の平均粒径が１０～５０ｎｍである請求項９に記載のガラス製品の製造方法。 The method for producing a glass product according to claim 9, wherein the colloidal silica abrasive has an average particle size of 10 to 50 nm.
  11. 　前記コロイダルシリカ砥粒を含むスラリーのｐＨが１～６である請求項９または１０に記載のガラス製品の製造方法。 The method for producing a glass product according to claim 9 or 10, wherein the slurry containing the colloidal silica abrasive has a pH of 1 to 6.
  12. 　ガラス製品がガラス基板である請求項１～１１のいずれか１項に記載のガラス製品の製造方法。 The method for producing a glass product according to any one of claims 1 to 11, wherein the glass product is a glass substrate.
  13. 　ガラス基板が情報記録媒体用ガラス基板である請求項１２に記載のガラス製品の製造方法。 The method for producing a glass product according to claim 12, wherein the glass substrate is a glass substrate for an information recording medium.
  14. 　請求項１～１３のいずれか１項に記載のガラス製品の製造方法によって磁気ディスク用ガラス基板を製造し、当該磁気ディスク用ガラス基板の主表面に磁気記録層を形成することを特徴とする磁気ディスクの製造方法。 A magnetic disk glass substrate is manufactured by the glass product manufacturing method according to any one of claims 1 to 13, and a magnetic recording layer is formed on a main surface of the magnetic disk glass substrate. Disc manufacturing method.
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