WO2015083713A1 - ガラス基板の仕上げ研磨方法、および、該方法で仕上げ研磨された無アルカリガラス基板 - Google Patents
ガラス基板の仕上げ研磨方法、および、該方法で仕上げ研磨された無アルカリガラス基板 Download PDFInfo
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Images
Classifications
-
- 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
- C03C3/00—Glass compositions
- C03C3/04—Glass compositions containing silica
- C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
- C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
- C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
-
- 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
- C03C3/00—Glass compositions
- C03C3/04—Glass compositions containing silica
- C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
- C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
- C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
- C03C3/093—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium containing zinc or zirconium
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B18/00—Shaping glass in contact with the surface of a liquid
- C03B18/02—Forming sheets
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02002—Preparing wafers
- H01L21/02005—Preparing bulk and homogeneous wafers
- H01L21/02008—Multistep processes
- H01L21/0201—Specific process step
- H01L21/02024—Mirror polishing
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
- H01L21/30625—With simultaneous mechanical treatment, e.g. mechanico-chemical polishing
Definitions
- the present invention relates to a method for finish polishing an alkali-free glass substrate substantially free of alkali metal oxides for use as various display glass substrates and photomask glass substrates, and a non-polishing finish polished by the method.
- the present invention relates to an alkali glass substrate.
- the following characteristics have been required for various display glass substrates, particularly those in which a metal or oxide thin film is formed on the surface.
- alkali metal oxide When an alkali metal oxide is contained, alkali metal ions diffuse into the thin film and deteriorate the film characteristics, so that the alkali metal ions are not substantially contained.
- the strain point When exposed to a high temperature in the thin film forming process, the strain point is high so that the deformation (thermal shrinkage) associated with glass deformation and glass structural stabilization can be minimized.
- BHF buffered hydrofluoric acid
- ITO various acids used for etching metal electrodes
- ITO various acids used for etching metal electrodes
- resistant to alkali of resist stripping solution Resistant to alkali of resist stripping solution.
- a-Si amorphous silicon
- p-Si polycrystalline silicon
- a glass having a small average thermal expansion coefficient is required to increase productivity and thermal shock resistance by increasing the temperature raising / lowering rate of the heat treatment for producing a liquid crystal display.
- Patent Document 1 discloses a glass containing 0 to 5 mol% of B 2 O 3 , but the average coefficient of thermal expansion at 50 to 350 ° C. exceeds 50 ⁇ 10 ⁇ 7 / ° C.
- the alkali-free glass described in Patent Document 2 has a high strain point and can be molded by a float process, and is said to be suitable for applications such as a display substrate and a photomask substrate.
- glass powder or glass removed by polishing can reduce the cost required for finish polishing by removing minute unevenness and waviness existing on the substrate surface with a smaller polishing amount. This is preferable for reasons such as less mixing of scrap into the polishing slurry and reduction in the frequency of replacement of the polishing slurry.
- a glass substrate formed by the float process has minute irregularities and undulations (a undulation with a maximum height of about 0.3 ⁇ m at a pitch of 3 to 30 mm) on its surface.
- Such minute irregularities and undulations are not a problem when a glass substrate molded by the float method is used as a glass plate for automobiles, buildings, etc., but is produced when used as a glass substrate for various displays. This may cause distortion and color unevenness in the display image. For this reason, it is necessary to remove minute irregularities and waviness by finish polishing.
- polishing using a polishing slurry containing cerium oxide as polishing abrasive grains is preferably used.
- An object of the present invention is to solve the above-mentioned drawbacks, a high strain point, low viscosity, when the temperature T 4 is polished low alkali glass substrate, especially a glass viscosity of 10 4 dPa ⁇ s, less polishing amount
- a glass substrate finish polishing method capable of removing minute irregularities and undulations existing on the substrate surface, and a non-alkali glass substrate finish polished by the method.
- the present invention is a glass substrate finish polishing method for polishing a main surface of a glass substrate using a polishing slurry containing cerium oxide as polishing abrasive grains,
- the composition of the glass substrate is the following alkali-free glass,
- X ⁇ m
- the temperature T 4 at which T 2 is 1710 ° C. or less and the glass viscosity is 10 4 dPa ⁇ s is 1330 ° C.
- MgO + CaO + SrO + BaO 2 is 15.5-21
- the undulation height converted to 20 mm pitch undulation of the main surface of the glass substrate before final polishing is 0.2 ⁇ m or less.
- finish polishing method of the glass substrate of the present invention it is preferable to finish polish the main surface of the glass substrate formed by the float process.
- the present invention also provides an alkali-free glass substrate that has been finish-polished using a glass substrate finish-polishing method.
- the undulation height converted to 20 mm pitch undulation of the main surface of the glass substrate after finish polishing is 0.07 ⁇ m or less.
- the surface roughness of 5 ⁇ m square of the main surface of the glass substrate after finish polishing is preferably 0.30 nm or less.
- the glass substrate of the present invention preferably has a length of at least one side of 900 mm or more.
- the method of the present invention when a non-alkali glass substrate formed by using the float method is finish-polished, minute irregularities and undulations existing on the substrate surface can be removed with a small amount of polishing, and as a display substrate. High flatness suitable for use can be achieved.
- the alkali-free glass substrate finish-polished by the method of the present invention is particularly suitable for a display substrate, a photomask substrate, a magnetic disk glass substrate and the like for high strain point applications.
- FIG. 1 is a schematic diagram showing the relationship between pitch and waviness.
- FIG. 2 is a perspective view showing the overall structure of a polishing apparatus to which the glass substrate finish polishing method of the embodiment is applied.
- FIG. 3 is a side view of the polishing apparatus 10 shown in FIG.
- FIG. 4 is a schematic view showing a sharpening method of a polishing tool using a truing grindstone of the embodiment.
- FIG. 5 is a plan view of the polishing tool sharpened by the sharpening method shown in FIG.
- FIG. 6 is a side view showing a method of repairing the polishing tool using the water nozzle for dressing.
- an alkali-free glass substrate using a glass raw material prepared so as to have the following glass composition is used.
- SiO 2 63 to 74 in terms of mol% based on oxide, Al 2 O 3 11.5-16, B 2 O 3 greater than 1.5 and less than 5, MgO 5.5-13, CaO 1.5-12, SrO 1.5-9, BaO 0 ⁇ 1, ZrO 2 0-2, MgO + CaO + SrO + BaO 2 is 15.5-21,
- the composition range of each component will be described. If the SiO 2 content is less than 63% (mol%, the same unless otherwise specified), the strain point is not sufficiently increased, the thermal expansion coefficient is increased, and the density is increased. In addition, the chemical durability, particularly acid resistance, of the glass is lowered, the convexity selectivity at the time of polishing is difficult to be obtained, and smoothness is difficult to obtain. It is preferably 64% or more, more preferably 65% or more, further preferably 66% or more, and particularly preferably 66.5% or more.
- the solubility decreases, the temperature T 4 which is a temperature T 2 and 10 4 dPa ⁇ s glass viscosity becomes 10 2 dPa ⁇ s is increased, the liquidus temperature rises. 70% or less is preferable, 69% or less is more preferable, and 68% or less is more preferable.
- Al 2 O 3 increases the Young's modulus and suppresses deformation during glass polishing, suppresses phase separation of the glass, lowers the thermal expansion coefficient, increases the strain point, improves hardness, and selects convex portions during polishing. However, if it is less than 11.5%, this effect does not appear, and other components that increase the expansion are increased, resulting in an increase in thermal expansion. It is preferably 12% or more, 12.5% or more, and more preferably 13% or more. If it exceeds 16%, the solubility of the glass may be deteriorated, or the devitrification temperature may be increased. It is preferably 15% or less, more preferably 14% or less, and further preferably 13.5% or less.
- B 2 O 3 improves the melting reactivity of the glass, lowers the devitrification temperature, and improves the BHF resistance, but this effect is not sufficiently exhibited at 1.5% or less, and the strain point is low. It tends to become excessively high or become a haze problem after treatment with BHF. 2% or more is preferable, and 3% or more is more preferable. However, if the amount is too large, the photoelastic constant increases, and problems such as color unevenness are likely to occur when stress is applied. Further, B 2 O 3 is less likely to appear smoothness by too large, the Young's modulus deformation during polishing decreases, and the surface roughness after polishing becomes large. In addition, the strain point also decreases. Therefore, it is 5% or less, preferably 4.5% or less, more preferably 4% or less.
- MgO has the feature of increasing the Young's modulus while keeping the density low while keeping the density low in alkaline earths, and improves the solubility. However, if it is less than 5.5%, this effect appears sufficiently.
- the density increases because the ratio of other alkaline earths increases. 6% or more, more preferably 7% or more, 7.5% or more, 8% or more, more preferably more than 8%, more preferably 8.1% or more, more preferably 8.3% or more, and particularly preferably 8.5% or more preferable. If it exceeds 13%, the devitrification temperature rises. It is preferably 12% or less, more preferably 11% or less, and particularly preferably 10% or less.
- CaO has the characteristics of increasing the Young's modulus while maintaining the low density without increasing the expansion in alkaline earth following MgO, and also improves the solubility. If it is less than 1.5%, the above-described effect due to the addition of CaO is not sufficiently exhibited. It is preferably 2% or more, more preferably 3% or more, further preferably 3.5% or more, and particularly preferably 4% or more. However, if it exceeds 12%, the devitrification temperature may increase, or a large amount of phosphorus, which is an impurity in limestone (CaCO 3 ), which is a CaO raw material, may be mixed. It is preferably 10% or less, more preferably 9% or less, further preferably 8% or less, and particularly preferably 7% or less.
- SrO improves the solubility without increasing the devitrification temperature of the glass, but if it is less than 1.5%, this effect does not appear sufficiently. 2% or more is preferable, 2.5% or more is more preferable, and 3% or more is more preferable. However, if it exceeds 9%, the expansion coefficient may increase. It is preferably 7% or less, more preferably 6% or less and 5% or less.
- BaO is not essential, but can be contained to improve solubility. However, if the amount is too large, the glass becomes brittle and easily damaged, and the expansion and density are excessively increased. 0.5% or less is preferable, 0.3% or less is more preferable, 0.1% or less is further preferable, and it is particularly preferable that it is not substantially contained. “Substantially not contained” means not containing any inevitable impurities (hereinafter the same).
- ZrO 2 may be incorporated up to 2% in order to increase the Young's modulus, to lower the glass melting temperature, or to promote crystal precipitation during firing. If it exceeds 2%, the glass becomes unstable or the relative dielectric constant ⁇ of the glass increases. Preferably it is 1.5% or less, More preferably, it is 1.0% or less, More preferably, it is 0.5% or less, and it is especially preferable not to contain substantially.
- the Young's modulus is low, it is difficult to suppress deformation during polishing, and the hardness is low, so that it is difficult to obtain the convexity selectivity during polishing.
- the photoelastic constant increases and the solubility further decreases. 16% or more is preferable, and 17% or more is more preferable. If it exceeds 21%, there is a risk that the thermal expansion coefficient cannot be reduced. It is preferably 20% or less, 19% or less, and more preferably 18% or less.
- MgO / (MgO + CaO + SrO + BaO) is 0.35 or more, preferably 0.37 or more, and more preferably 0.4 or more.
- CaO / (MgO + CaO + SrO + BaO) is 0.50 or less, preferably 0.48 or less, and more preferably 0.45 or less.
- SrO / (MgO + CaO + SrO + BaO) is 0.50 or less, preferably 0.40 or less, more preferably 0.30 or less, more preferably 0.27 or less, and further preferably 0.25 or less.
- Al 2 O 3 ⁇ (MgO / (MgO + CaO + SrO + BaO)) is 4.1 or more because the Young's modulus is increased and deformation during polishing is easily suppressed.
- it is 4.3 or more, More preferably, it is 4.5 or more, More preferably, it is 4.7 or more, Most preferably, it is 5.0 or more.
- the glass raw material preferably does not substantially contain P 2 O 5 . Furthermore, in order to facilitate recycling of the glass, it is preferable that the glass raw material does not substantially contain PbO, As 2 O 3 , or Sb 2 O 3 .
- the glass contains ZnO, Fe 2 O 3 , SO 3 , F, Cl, SnO 2 at 1% or less, preferably 0.5% or less, more preferably It can be contained in an amount of 0.3% or less, more preferably 0.15% or less, and particularly preferably 0.1% or less. It is preferable that ZnO is not substantially contained.
- the production of the alkali-free glass substrate of the present invention is performed, for example, according to the following procedure.
- the raw materials of each component are prepared so as to become target components, which are continuously charged into a melting furnace, heated to 1500-1800 ° C. and melted.
- the molten glass is formed into a plate-like glass ribbon having a predetermined plate thickness by a forming apparatus, and the glass ribbon is gradually cooled and then cut to obtain an alkali-free glass substrate.
- FIG. 2 is a perspective view showing the overall configuration of the polishing apparatus 10 to which the glass substrate finish polishing method of the embodiment is applied.
- FIG. 3 is a side view of the polishing apparatus 10 shown in FIG.
- the polishing apparatus 10 shown in these figures is a glass plate G manufactured by a float process, for example, a glass having a thickness of 0.7 mm or less, a side length of 900 mm or more, and a Young's modulus of 65 GPa or more.
- This is a polishing apparatus that polishes the main surface (polishing surface) of the plate G to a flatness necessary for the glass substrate for FPD using a polishing tool. That is, the polishing apparatus 10 polishes the polished surface of the glass plate G on which undulations with a undulation of 0.2 ⁇ m or less converted into undulations with a pitch of 20 mm are obtained, and the undulation height converted into undulations with a pitch of 20 mm.
- the thickness By reducing the thickness to 0.07 ⁇ m or less, it is an apparatus for producing an optimum glass plate as a glass substrate for FPD which does not give distortion or color unevenness to an image. Further, in the present invention, by setting the Young's modulus of the glass plate G to 78 GPa or more, for example, a thin plate having a thickness of 0.5 mm or less or a large plate having a side length of 1000 mm or more can be used. The main surface (polishing surface) of the plate G can be polished to a flatness necessary for the glass substrate for FPD using a polishing tool.
- the measuring method of the said waviness is a method as described in JIS B0031: '82 and JIS B0601: '82.
- the pitch and waviness can be defined as shown in FIG.
- the undulation height converted to the undulation of the 20 mm pitch can be obtained. It is more preferable that the undulation height converted to the undulation of 20 mm pitch on the main surface of the glass substrate before finish polishing is 0.17 ⁇ m or less. Moreover, it is more preferable that the height of the undulation converted to the undulation of the 20 mm pitch of the main surface of the glass substrate after finish polishing is 0.05 ⁇ m or less.
- the polishing apparatus 10 includes a polishing head 12 and a surface plate 14.
- the polishing head 12 is provided with a glass holding member 16 that holds the non-polished surface of the glass plate G, a glass holding surface plate 20 to which the glass holding member 16 is attached via a sealing material 18, and a glass holding surface plate 20.
- a canvas 22 is provided.
- a rotating shaft 24 is fixed to the canvas 22, and the rotating shaft 24 is rotated about its axis P1, whereby the polishing head 12 is rotated and the rotating shaft 24 is revolved about the revolution axis P2. As a result, the polishing head 12 is revolved.
- compressed air is supplied to the air chamber 23 of the canvas 22 through a hollow rotating shaft 24, and the pressure of the compressed air is reduced to glass through the glass holding surface plate 20, the sealing material 18, and the glass holding member 16. Is transmitted to the plate G.
- the surface plate 14 includes a polishing tool 26 and a polishing tool holding surface plate 30 to which the polishing tool 26 is attached via a sealing material 28.
- the sealing material 28 is a resin-made sealing material (for example, made of polyurethane) that is soft and improves adsorption retention.
- the polishing apparatus 10 polishes the polishing surface of the glass plate G by pressing the polishing surface of the glass plate G against the polishing tool 26 by the pressure of the compressed air and rotating and revolving the polishing head 12. To do.
- the polishing tool 26 has an A hardness (according to ISO 7619) of 20 or more, a D hardness (according to ISO 7619) of 99 or less, a thickness of 1.0 to 2.5 mm, and a thickness distribution within ⁇ 0.3 mm. It is preferable that it is within ⁇ 0.05 mm.
- the A hardness of the polishing tool 26 is less than 20, the undulation of the glass plate G cannot be reduced, and when the D hardness exceeds 99, the glass plate G is easily broken. Further, if the thickness of the polishing tool 26 is less than 1 mm, the polishing tool 26 cannot be grooved. In particular, if the polishing tool 26 having a large area cannot perform the groove processing, the abrasive grain distribution becomes non-uniform and a problem occurs in the processing of the glass plate G. On the other hand, when the thickness of the polishing tool 26 exceeds 2.5 mm, the deformation allowance of the polishing tool 26 is increased, and the processing quality of the glass plate G is deteriorated.
- the thickness distribution of the polishing tool 26 is the maximum thickness-minimum thickness in the region excluding the groove processed portion. When this thickness distribution exceeds ⁇ 0.3 mm, the pressure distribution becomes large and the processing quality of the glass plate is lowered.
- the thickness distribution is preferably within ⁇ 0.2 mm, more preferably within ⁇ 0.1 mm, and even more preferably within ⁇ 0.05 mm.
- the glass plate G manufactured by the float process can be polished to a glass plate that is more optimal as a glass substrate for FPD. it can.
- the inventor of the present application has not been sufficient to manage the A hardness of the polishing tool 26 in order to make the undulation height converted to the undulation of 20 mm pitch 0.07 ⁇ m or less. It is preferable to manage the compression rate, compression elastic modulus, A hardness, thickness, and thickness distribution.
- the glass holding member 16 absorbs the undulation existing on the non-polished surface of the glass plate G, and therefore exists on the polished surface of the glass plate G.
- the waviness can be satisfactorily polished by the polishing tool 26.
- the polishing surface of the glass plate G is removed by the polishing tool 26 in a state where the undulation existing on the non-polished surface of the glass plate G cannot be absorbed by the glass holding member 16.
- the glass plate G Since polishing is performed, when the glass plate G is detached from the glass holding member 16, the glass plate G causes a spring back, and as a result, the polished surface of the glass plate G has a swell height converted to a swell of 20 mm pitch. There is a risk that undulation exceeding 0.07 ⁇ m may remain.
- the cushioning property of the glass holding member 16 may be uneven within the surface of the glass plate G, and there may be a problem that the swell does not disappear uniformly.
- Compressive modulus represents the cushioning property that follows the initial glass plate G, and the compressive elastic modulus is a parameter necessary to represent the degree of restoration when repeatedly used.
- the glass holding member 16 is made of polyurethane foam.
- the glass holding member 16 has a compression rate (according to JIS L1021-6: '07 Annex 1) of 10 to 70%, and a compression elastic modulus (JIS L1021-6: '07 Annex 1).
- the initial load is 100 gf / cm 2
- the final load is 1120 gf / cm 2
- the A hardness is 2 to 20
- the thickness is 0.3 to 2.0 mm
- the thickness distribution is ⁇ 0. It is preferably within 0.05 mm.
- the management of the glass holding member 16 needs to narrow the management range particularly when the glass plate G becomes thin.
- the glass holding member 16 in the case of a glass plate G having a thickness of 0.5 mm or less has a compression rate of 10 to 70%, a compression elastic modulus of 70 to 98, an A hardness of 2 to 20, and a thickness of 0.5. It is preferable that the thickness distribution is within. ⁇ .0.05 mm and .about.1.5 mm.
- the glass holding member 16 in the case of the glass plate G having a thickness of 0.3 mm or less has a compression rate of 10 to 70%, a compression elastic modulus of 70 to 98, an A hardness of 2 to 20, and a thickness of 0.7. It is preferable that the thickness distribution is within ⁇ 0.05 mm.
- the glass plate G manufactured by the float process is further optimized as a glass substrate for FPD. Can be polished to a plate.
- the maximum sectional height of the undulation curve when the evaluation length is 30 mm is 20 ⁇ m or less.
- the glass holding member 16 Even if the glass holding member 16 is managed, if the maximum cross-sectional height of the waviness curve of the glass holding surface plate 20 is too high, the glass holding member 16 absorbs the waviness present on the non-polished surface of the glass plate G. However, it becomes difficult to polish the waviness of the polished surface of the glass plate G to 0.07 ⁇ m or less in terms of the waviness height converted to a waviness of 20 mm pitch.
- the undulation existing on the non-polished surface of the glass plate G can be satisfactorily absorbed by the glass holding member 16.
- the glass plate can be polished to a glass plate more optimal as a glass substrate for FPD.
- the maximum sectional height of the sectional curve when the evaluation length is 30 mm is 100 ⁇ m or less.
- a glass plate manufactured by the float process is used as an FPD. It can grind
- the maximum cross-sectional height of the undulation curve is described in JIS B0601: '01.
- the variation in the load for pressing the polishing surface of the glass plate G against the polishing tool 26 is 10% or less of the average load.
- the glass plate G manufactured by the float process can be polished to a glass plate more optimal as a glass substrate for FPD.
- “BIG-MAT” or “HUGE-MAT” of a large area pressure distribution measuring system manufactured by Nitta Corporation can be used.
- the glass plate G manufactured by the float process has a thickness of 0.7 mm or less, a side length of 900 mm or more, and a Young's modulus.
- the glass plate G of 65 GPa or more is the object to be polished, the non-polished surface of the glass plate G is held by the glass holding member 16, and the waviness height converted to 20 mm pitch waviness on the polished surface of the glass plate G is 0.2 ⁇ m.
- the swell height converted to a 20 mm pitch swell is reduced to 0.07 ⁇ m or less to produce a glass substrate for flat panel display.
- the optimal glass plate G as a glass substrate for FPD which does not give distortion and uneven color to an image can be manufactured.
- polishing when the amount of polishing of the glass substrate when the undulation height converted to 20 mm pitch undulation changes from 0.14 ⁇ m to 0.10 ⁇ m is X ( ⁇ m), 0 Polishing is performed under the condition that 0.04 / X is 0.12 or more. As a result, the cost required for finish polishing is reduced, and the glass powder or glass waste removed by polishing is less mixed into the polishing slurry and the frequency of replacement of the polishing slurry can be reduced. It is more preferable to perform the polishing under the condition that 0.04 / X is 0.13 or more, further preferably 0.14 or more, and particularly preferable to perform the polishing under the condition of 0.15 or more. .
- the polishing conditions are as follows: The above condition is not limited to 0.04 / X being 0.12 or more. However, it is preferable to carry out under the condition that 0.04 / X is 0.12 or more.
- the polishing condition when the waviness height converted to waviness with a pitch of 20 mm is made smaller than 0.10 ⁇ m is 0.04 / X, which is 0.04 / X described above. It is not limited to the conditions which become 12 or more, You may implement on the conditions from which 0.04 / X mentioned above becomes smaller than 0.12.
- the undulation height converted to the 20 mm pitch undulation of the main surface of the glass substrate before finish polishing is 0.2 ⁇ m or less. Thereby, the polishing time required for finishing can be reduced, and excellent flatness can be easily obtained.
- the waviness height converted to a 20 mm pitch waviness is more preferably 0.17 ⁇ m or less, and still more preferably 0.15 ⁇ m or less.
- the undulation height converted to the 20 mm pitch undulation of the main surface of the glass substrate after finish polishing is 0.07 ⁇ m or less.
- the undulation height converted to 20 mm pitch undulation is more preferably 0.05 ⁇ m or less, and even more preferably 0.03 ⁇ m or less.
- the surface roughness Ra of 5 ⁇ m square by AFM on the main surface of the glass substrate after finish polishing is preferably 0.30 nm or less. This makes it easier to obtain stable driving characteristics in a display using this substrate.
- polishing specifications An example of polishing specifications is shown below.
- Polishing pressure 2 kPa to 25 kPa
- Polishing slurry cerium oxide aqueous solution is supplied from the slurry supply hole of the polishing tool holding surface plate.
- Polishing tool Suede made of soft urethane with grooves that allow slurry to flow on the surface (groove pitch 4.5 mm, groove width 1.5 mm, groove depth) 1 ⁇ 1.5mm)
- Glass plate thickness 0.2 mm to 0.7 mm
- Shape of glass plate rectangular glass plate having a side of 900 mm or more
- Non-polished surface of glass plate held tightly by a glass holding member The above is an example of polishing specifications.
- the surface of the polishing tool 26 is periodically ground with a truing grindstone containing diamond abrasive grains, and sharpening is performed. Yes.
- a rectangular frame 42 having no diamond abrasive grains and having no grinding ability surrounds a truing grindstone 40 as shown in a plan view of FIG.
- the glass holding member 16 is attached. Then, the truing grindstone 40 and the frame 42 are pressed against the polishing tool 26 by the air pressure of the compressed air supplied to the air chamber 23 of the canvas 22, and the surface of the polishing tool 26 is ground by the truing grindstone 40.
- the air pressure is concentrated on the frame 42 located on the outer periphery of the truing grindstone 40.
- the frame 42 does not have a grinding ability, a part of the surface of the polishing tool 26 that contacts the frame 42 is not ground. . That is, the surface of the polishing tool 26 is ground only by the truing grindstone 40 to which the air pressure is uniformly applied. Thereby, since the whole surface of the grinding
- the frame 42 it is preferable to use the frame 42 not only when the polishing tool 26 is truing but also when the glass plate G is polished. Thereby, it is possible to prevent the air pressure from being concentrated on the edge of the glass plate G when the glass plate G is polished, so that excessive grinding of the edge of the glass plate G can be prevented.
- the material of the frame 42 include materials having no polishing ability, such as stainless steel, iron, aluminum, polyethylene, and polyurethane.
- the surface of the polishing tool 26 is periodically washed with water, so that the polishing liquid adhering to the surface of the polishing tool 26 is removed.
- the dressing water nozzle 44 is inclined, and the spray angle ⁇ of the cleaning water 48 sprayed from the spray holes 46 is set to an acute angle. And the residue adhering to the surface of the polishing tool 26 is removed by reciprocating the water nozzle 44 and the polishing tool 26 in the horizontal direction.
- the injection angle ⁇ of the cleaning water 48 is preferably 10 to 45 degrees, more preferably 30 degrees, from the viewpoints of residue digging efficiency and residue washing efficiency.
- the striking force when the cleaning water 48 collides with the polishing tool 26 is preferably 5 to 50 kPa because the removal efficiency of the residue decreases if it is weak and the polishing tool 26 may be damaged if it is high.
- the relative speed of the polishing tool 26 and the water nozzle 44 is preferably 3 to 20 m / min since the dressing efficiency of the polishing tool 26 decreases if it is slow, and the removal efficiency of the residue decreases if it is fast.
- the alkali-free glass substrate of the present invention has a strain point of 680 ° C. or higher and 735 ° C. or lower. Since the alkali-free glass of the present invention has a strain point of 680 ° C. or higher, thermal shrinkage during panel production can be suppressed. Further, a laser annealing method can be applied as a method for manufacturing the p-Si TFT. 685 degreeC or more is more preferable, and 690 degreeC or more is further more preferable. Since the alkali-free glass of the present invention has a strain point of 680 ° C.
- a high strain point for example, a display substrate having a thickness of 0.7 mm or less, preferably 0.5 mm or less, more preferably 0.3 mm or less.
- an illumination substrate or a thin display substrate or illumination substrate having a thickness of 0.3 mm or less, preferably 0.1 mm or less.
- the strain point is 735 ° C. or lower, it is not necessary to raise the temperature of the float bath and the exit of the float bath so much that it affects the life of the metal member located in the float bath and on the downstream side of the float bath. Few. 725 ° C or lower is more preferable, 715 ° C or lower is further preferable, and 710 ° C or lower is particularly preferable. Further, in order to improve the plane strain of the glass, it is necessary to increase the temperature at the part entering the annealing furnace from the float bath outlet, but it is not necessary to increase the temperature at this time. For this reason, a load is not applied to the heater used for heating, and the life of the heater is hardly affected.
- the alkali-free glass substrate of the present invention has a glass transition point of preferably 730 ° C. or higher, more preferably 740 ° C. or higher, and further preferably 750 ° C. or higher. Moreover, 780 degrees C or less is preferable, 775 degrees C or less is more preferable, and 770 degrees C or less is especially preferable.
- the alkali-free glass substrate of the present invention has an average coefficient of thermal expansion at 50 to 350 ° C. of 30 ⁇ 10 ⁇ 7 to 43 ⁇ 10 ⁇ 7 / ° C., and has high thermal shock resistance. Productivity when manufacturing the used display can be increased.
- the average thermal expansion coefficient at 50 to 350 ° C. is preferably 35 ⁇ 10 ⁇ 7 to 40 ⁇ 10 ⁇ 7 / ° C.
- the average thermal expansion coefficient at 50 to 350 ° C. is preferably 42 ⁇ 10 ⁇ 7 / ° C. or less, more preferably 41 ⁇ 10 ⁇ 7 / ° C. or less, and further preferably 40 ⁇ 10 ⁇ 7 / ° C. or less.
- the non-alkali glass substrate of the present invention preferably has a specific gravity of 2.62 or less, more preferably 2.60 or less, and even more preferably 2.58 or less.
- the alkali-free glass substrate of the present invention preferably has a specific elastic modulus of 31 MNm / kg or more. If it is less than 31 MNm / kg, it becomes difficult to obtain the convexity selectivity at the time of polishing due to its own weight deflection. More preferably, it is 32 MNm / kg or more.
- the alkali-free glass substrate of the present invention preferably has a Young's modulus of 78 GPa or more. If it is less than 78 GPa, the glass substrate is deformed at the time of polishing, and it is difficult to obtain smoothness, and the deformation makes it difficult to obtain the convexity selectivity at the time of polishing. More preferably, it is 80 GPa or more, More preferably, 81 GPa or more, Most preferably, 82 GPa or more is preferable.
- the alkali-free glass substrate of the present invention preferably has a photoelastic constant of 30 nm / MPa / cm or less. Due to the birefringence of the glass substrate due to stress generated during the manufacturing process of the liquid crystal display panel and the liquid crystal display device, a phenomenon in which the black display becomes gray and the contrast of the liquid crystal display decreases may be observed. By setting the photoelastic constant to 30 nm / MPa / cm or less, this phenomenon can be suppressed small. Preferably it is 29 nm / MPa / cm or less, More preferably, it is 28.5 nm / MPa / cm or less, More preferably, it is 28 nm / MPa / cm or less.
- the alkali-free glass substrate of the present invention has a photoelastic constant of preferably 23 nm / MPa / cm or more, more preferably 25 nm / MPa / cm or more, considering the ease of securing other physical properties.
- the photoelastic constant can be measured by a disk compression method at a measurement wavelength of 546 nm.
- the alkali-free glass substrate of the present invention preferably has a relative dielectric constant of 5.6 or more.
- the sensing sensitivity of the touch sensor is improved, the driving voltage is reduced, From the viewpoint of power saving, it is better that the glass substrate has a higher relative dielectric constant.
- the relative dielectric constant can be measured by the method described in JIS C-2141.
- the temperature T 2 at which the viscosity ⁇ becomes 10 2 poise is 1710 ° C. or less, preferably less than 1710 ° C., more preferably 1700 ° C. or less, more preferably Since it is 1690 ° C. or less, particularly preferably 1660 ° C. or less, dissolution is relatively easy.
- the alkali-free glass substrate of the present invention has a temperature T 4 at which the viscosity ⁇ becomes 10 4 poise, 1330 ° C. or less, preferably 1320 ° C. or less, more preferably 1315 ° C. or less, further preferably 1310 ° C. or less, particularly preferably. It is 1300 ° C. or lower and is suitable for float forming.
- the alkali-free glass substrate of the present invention preferably has a devitrification temperature of 1350 ° C. or less because molding by the float method becomes easy.
- a devitrification temperature is obtained by putting crushed glass particles in a platinum dish and performing heat treatment for 17 hours in an electric furnace controlled at a constant temperature. It is an average value of the maximum temperature at which crystals are deposited inside and the minimum temperature at which crystals are not deposited.
- Example 1 Comparative Example 1
- the raw material of each component was prepared so that it might become the target composition shown in Table 1, and it melt
- a cerium oxide aqueous solution is polished on a pad having grooves with a groove pitch of 4.5 mm, a groove width of 1.5 mm, and a groove depth of 1 to 1.5 mm. Polishing was performed while supplying from the slurry supply hole of the holding surface plate.
- the glass is extracted, the amount of polishing and the undulation height of the main surface of the glass substrate are measured repeatedly, and the polishing is repeated, and the relationship between the polishing amount and the undulation height converted to 20 mm pitch undulation is obtained. It was. From the result, the polishing amount X ( ⁇ m) of the glass substrate when the waviness height converted to 20 mm pitch waviness on the main surface of the glass substrate changes from 0.14 ⁇ m to 0.10 ⁇ m is obtained. The value of / X was determined. In addition, the 20 mm pitch waviness height of the main surface of the glass substrate before and after final polishing and the surface roughness Ra of 5 ⁇ m square of the main surface of the glass substrate after final polishing were also measured.
- the surface roughness Ra was obtained by using NanoScope IIIa manufactured by Digital Instruments, with a scan rate of 1 Hz, and a surface roughness of 5 ⁇ m square at 256 points / scan. The results are shown in Table 2 below. In addition, about the alkali free glass substrate obtained by said procedure, the strain point, the Young's modulus, the specific elastic modulus, and the photoelastic constant were also measured. The results are shown in Table 2. Parentheses indicate calculated values.
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Abstract
Description
(1)アルカリ金属酸化物を含有していると、アルカリ金属イオンが薄膜中に拡散して膜特性を劣化させるため、実質的にアルカリ金属イオンを含まないこと。
(2)薄膜形成工程で高温にさらされる際に、ガラスの変形およびガラスの構造安定化に伴う収縮(熱収縮)を最小限に抑えうるように、歪点が高いこと。
(4)内部および表面に欠点(泡、脈理、インクルージョン、ピット、キズ等)がないこと。
(5)ディスプレイの軽量化が要求され、ガラス自身も密度の小さいガラスが望まれる。
(6)ディスプレイの軽量化が要求され、ガラス基板の薄板化が望まれる。
(8)液晶ディスプレイ作製熱処理の昇降温速度を速くして、生産性を上げたり耐熱衝撃性を上げるために、ガラスの平均熱膨張係数の小さいガラスが求められる。
一方、フロート法で成形されたガラス基板は、その表面に微小な凹凸やうねり(3~30mmのピッチで、最大高さが0.3μm程度のうねり)が存在する。このような微小な凹凸やうねりは、フロート法で成形されたガラス基板を、自動車用、建築等の板ガラスとして使用する場合は問題とならないが、各種ディスプレイ用ガラス基板として使用する場合は、製造されるディスプレイの画像に歪みや色むらを与える原因となる。このため、仕上げ研磨により、微小な凹凸やうねりを除去することが必要となる。
このような目的で実施する仕上げ研磨には、研磨砥粒として酸化セリウムを含む研磨スラリを用いた研磨が好ましく用いられる。
また、ガラス製造プロセス、特に溶解、成形における要請から、ガラスの粘性、特にガラス粘度が104dPa・sとなる温度T4を低くすることが求められている。
前記ガラス基板の組成が、下記の無アルカリガラスであり、
前記ガラス基板の主面の20mmピッチのうねりに換算したうねりの高さが0.14μmから0.10μmまで変化する際の前記ガラス基板の研磨量をX(μm)とするとき、0.04/Xが0.12以上となる条件で研磨する段階を含む、ガラス基板の仕上げ研磨方法を提供する。
歪点が680~735℃であって、50~350℃での平均熱膨張係数が30×10-7~43×10-7/℃であって、ガラス粘度が102dPa・sとなる温度T2が1710℃以下であって、ガラス粘度が104dPa・sとなる温度T4が1330℃以下であって、酸化物基準のモル%表示で
SiO2 63~74、
Al2O3 11.5~16、
B2O3 1.5超5以下、
MgO 5.5~13、
CaO 1.5~12、
SrO 1.5~9、
BaO 0~1、
ZrO2 0~2を含有し
MgO+CaO+SrO+BaO が15.5~21であり、
MgO/(MgO+CaO+SrO+BaO)が0.35以上であり、CaO/(MgO+CaO+SrO+BaO)が0.50以下であり、SrO/(MgO+CaO+SrO+BaO)が0.50以下である無アルカリガラス。
本発明の方法により仕上げ研磨された無アルカリガラス基板は、特に高歪点用途のディスプレイ用基板、フォトマスク用基板、また磁気ディスク用ガラス基板等に好適である。
本発明のガラス基板の仕上げ研磨方法では、下記ガラス組成となるように調合したガラス原料を用いた無アルカリガラス基板を使用する。
酸化物基準のモル%表示で
SiO2 63~74、
Al2O3 11.5~16、
B2O3 1.5超5以下、
MgO 5.5~13、
CaO 1.5~12、
SrO 1.5~9、
BaO 0~1、
ZrO2 0~2を含有し
MgO+CaO+SrO+BaO が15.5~21であり、
MgO/(MgO+CaO+SrO+BaO)が0.35以上であり、CaO/(MgO+CaO+SrO+BaO)が0.50以下であり、SrO/(MgO+CaO+SrO+BaO)が0.50以下である無アルカリガラス。
MgO/(MgO+CaO+SrO+BaO)が0.35以上であり、0.37以上が好ましく、0.4以上がより好ましい。
CaO/(MgO+CaO+SrO+BaO)が0.50以下であり、0.48以下が好ましく、0.45以下がより好ましい。
SrO/(MgO+CaO+SrO+BaO)が0.50以下であり、0.40以下が好ましく、0.30以下がより好ましく、0.27以下がより好ましく、0.25以下がさらに好ましい。
各成分の原料を目標成分になるように調合し、これを溶解炉に連続的に投入し、1500~1800℃に加熱して溶融する。この溶融ガラスを成形装置にて、所定の板厚の板状のガラスリボンに成形し、このガラスリボンを徐冷後切断することによって、無アルカリガラス基板を得ることができる。
本発明では、フロート法にて板状のガラスリボンに成形することが好ましい。
また、本発明では、ガラス板Gのヤング率を78GPa以上とすることで、例えば、厚さが0.5mm以下の薄板や、1辺の長さが1000mm以上の大板であっても、ガラス板Gの主面(研磨面)を、研磨具を用いてFPD用ガラス基板に必要な平坦度に研磨することができる。
仕上げ研磨前のガラス基板の主面の20mmピッチのうねりに換算したうねりの高さは0.17μm以下であることがより好ましい。また、仕上げ研磨後のガラス基板の主面の20mmピッチのうねりに換算したうねりの高さは0.05μm以下であることがより好ましい。
うねり曲線の最大断面高さは、測定長30mm、λC=0.8mmの測定条件で株式会社東京精密製サーフコム「1400-D64」にて測定する。
また、本発明の仕上げ研磨方法において、20mmピッチのうねりに換算したうねりの高さを0.10μmよりも小さくする際の研磨についても、その研磨条件は、上述した0.04/Xが0.12以上となる条件には限定されず、上述した0.04/Xが0.12よりも小さくなる条件で実施してもよい。
本発明のガラス基板の仕上げ研磨方法は、仕上げ研磨後のガラス基板の主面の20mmピッチのうねりに換算したうねりの高さが0.07μm以下であることが好ましい。これにより、この基板を用いたディスプレイにおいて画像に歪みや色むらが生じにくくなる。20mmピッチのうねりに換算したうねりの高さはより好ましくは0.05μm以下、さらに好ましくは0.03μm以下である。
本発明のガラス基板の仕上げ研磨方法は、仕上げ研磨後のガラス基板の主面のAFMによる5μm四方の表面粗さRaが0.30nm以下であることが好ましい。これにより、この基板を用いたディスプレイにおいて安定した駆動特性が得られやすくなる。
研磨スラリ:酸化セリウム水溶液を研磨具保持定盤のスラリ供給孔から供給
研磨具:軟質ウレタン製スエード状で表面にスラリを流す溝有り(溝ピッチ4.5mm、溝幅1.5mm、溝深さ1~1.5mm)
ガラス板の厚み:0.2mm~0.7mm
ガラス板の形状:1辺が900mm以上の矩形状ガラス板
ガラス板の非研磨面:ガラス保持部材にて密着保持
以上が研磨仕様の一例である。
実施の形態の研磨装置10では、図4に示すように、ダイヤモンド砥粒を有さず研削能力のない矩形状のフレーム42を、図5の平面図に示すようにツルーイング砥石40を包囲するようにガラス保持部材16に取り付けている。そして、キャンバス22の空気室23に供給された圧縮エアのエア圧によってツルーイング砥石40、及びフレーム42を研磨具26に押し付けて、研磨具26の面をツルーイング砥石40によって研削する。
本発明の無アルカリガラスは、歪点が680℃以上であるため、パネル製造時の熱収縮を抑えられる。また、p-Si TFTの製造方法としてレーザーアニールによる方法を適用することができる。685℃以上がより好ましく、690℃以上がさらに好ましい。
本発明の無アルカリガラスは、歪点が680℃以上であるため、高歪点用途(例えば、板厚0.7mm以下、好ましくは0.5mm以下、より好ましくは0.3mm以下のディスプレイ用基板または照明用基板、あるいは板厚0.3mm以下、好ましくは0.1mm以下の薄板のディスプレイ用基板または照明用基板)に適している。
板厚0.7mm以下、さらには0.5mm以下、さらには0.3mm以下、さらには0.1mm以下の板ガラスの成形では、成形時の引き出し速度が速くなる傾向があるため、ガラスの仮想温度が上昇し、ガラスのコンパクションが増大しやすい。この場合、高歪点ガラスであると、コンパクションを抑制することができる。
一方、歪点が735℃以下であるため、フロートバス内及びフロートバス出口の温度をあまり高くする必要が無く、フロートバス内及びフロートバス下流側に位置する金属部材の寿命に影響を及ぼすことが少ない。725℃以下がより好ましく、715℃以下がさらに好ましく、710℃以下が特に好ましい。また、ガラスの平面歪を改善するため、フロートバス出口から徐冷炉に入る部分で温度を高くする必要があるが、この際の温度をあまり高くする必要がない。このため、加熱に使用するヒータに負荷がかかることがなく、ヒータの寿命に影響を及ぼすことが少ない。
液晶ディスプレイパネル製造工程や液晶ディスプレイ装置使用時に発生した応力によってガラス基板が複屈折性を有することにより、黒の表示がグレーになり、液晶ディスプレイのコントラストが低下する現象が認められることがある。光弾性定数を30nm/MPa/cm以下とすることにより、この現象を小さく抑えることができる。好ましくは29nm/MPa/cm以下、より好ましくは28.5nm/MPa/cm以下、さらに好ましくは28nm/MPa/cm以下である。
また、本発明の無アルカリガラス基板は、他の物性確保の容易性を考慮すると、光弾性定数が好ましくは23nm/MPa/cm以上、より好ましくは25nm/MPa/cm以上である。
なお、光弾性定数は円盤圧縮法により測定波長546nmにて測定できる。
日本国特開2011-70092号公報に記載されているような、インセル型のタッチパネル(液晶ディスプレイパネル内にタッチセンサを内蔵したもの)の場合、タッチセンサのセンシング感度の向上、駆動電圧の低下、省電力化の観点から、ガラス基板の比誘電率が高いほうがよい。比誘電率を5.6以上とすることにより、タッチセンサのセンシング感度が向上する。好ましくは5.8以上、より好ましくは5.9以上、さらに好ましくは6.0以上である。
なお、比誘電率はJIS C-2141に記載の方法で測定できる。
本明細書における失透温度は、白金製の皿に粉砕されたガラス粒子を入れ、一定温度に制御された電気炉中で17時間熱処理を行い、熱処理後の光学顕微鏡観察によって、ガラスの表面及び内部に結晶が析出する最高温度と結晶が析出しない最低温度との平均値である。
各成分の原料を、表1に示す目標組成になるように調合し、連続溶融窯にて溶解を行い、フロート法にて板成形を行い、無アルカリガラス基板を得た。
得られたガラス基板(920mm×730mm、厚さ0.5mm)を、溝ピッチ4.5mm、溝幅1.5mm、溝深さ1~1.5mmの溝を有するパッドに酸化セリウム水溶液を研磨具保持定盤のスラリ供給孔から供給しながら研磨を行った。途中、ガラスを抜き出し、研磨量とガラス基板の主面のうねりの高さを測定して再度研磨することを繰り返し実施し、研磨量と20mmピッチのうねりに換算したうねりの高さとの関係を求めた。
その結果から、ガラス基板の主面の20mmピッチのうねりに換算したうねりの高さが0.14μmから0.10μmまで変化する際の前記ガラス基板の研磨量X(μm)を求め、0.04/Xの値を求めた。また、仕上げ研磨前後のガラス基板の主面の20mmピッチのうねり高さ、仕上げ研磨後のガラス基板の主面の5μm四方の表面粗さRaの測定も行った。表面粗さRaは、Digital Instruments社製NanoScope IIIaにて、スキャンレートを1Hzとし、256点/1スキャンで5μm四方の表面粗さを求めた。
結果を下記表2に示す。
なお、上記の手順で得られた無アルカリガラス基板については、歪点、ヤング率、比弾性率、光弾性定数も測定した。結果を表2に示す。かっこは計算値を示す。
本出願は、2013年12月4日出願の日本特許出願2013-251021に基づくものであり、その内容はここに参照として取り込まれる。
10 研磨装置
12 研磨ヘッド
14 定盤
16 ガラス保持部材
18 シール材
20 ガラス保持定盤
22 キャンバス
23 空気室
24 回転軸
26 研磨具
28 シール材
30 研磨具保持定盤
40 ツルーイング砥石
42 フレーム
44 水ノズル
46 噴射孔
48 洗浄水
Claims (7)
- 研磨砥粒として酸化セリウムを含む研磨スラリを用いて、ガラス基板の主面を研磨する、ガラス基板の仕上げ研磨方法であって、
前記ガラス基板の組成が、下記の無アルカリガラスであり、
前記ガラス基板の主面の20mmピッチのうねりに換算したうねりの高さが0.14μmから0.10μmまで変化する際の前記ガラス基板の研磨量をX(μm)とするとき、0.04/Xが0.12以上となる条件で研磨する段階を含む、ガラス基板の仕上げ研磨方法。
歪点が680~735℃であって、50~350℃での平均熱膨張係数が30×10-7~43×10-7/℃であって、ガラス粘度が102dPa・sとなる温度T2が1710℃以下であって、ガラス粘度が104dPa・sとなる温度T4が1330℃以下であって、酸化物基準のモル%表示で
SiO2 63~74、
Al2O3 11.5~16、
B2O3 1.5超5以下、
MgO 5.5~13、
CaO 1.5~12、
SrO 1.5~9、
BaO 0~1、
ZrO2 0~2を含有し
MgO+CaO+SrO+BaO が15.5~21であり、
MgO/(MgO+CaO+SrO+BaO)が0.35以上であり、CaO/(MgO+CaO+SrO+BaO)が0.50以下であり、SrO/(MgO+CaO+SrO+BaO)が0.50以下である無アルカリガラス。 - 仕上げ研磨前のガラス基板の主面の20mmピッチのうねりに換算したうねりの高さが0.2μm以下である、請求項1に記載のガラス基板の仕上げ研磨方法。
- フロート法により成形されたガラス基板の主面を仕上げ研磨する、請求項1または2に記載のガラス基板の仕上げ研磨方法。
- 請求項1~3のいずれか一項に記載のガラス基板の仕上げ研磨方法を用いて仕上げ研磨された無アルカリガラス基板。
- 仕上げ研磨後のガラス基板の主面の20mmピッチのうねりに換算したうねりの高さが0.07μm以下である、請求項4に記載の無アルカリガラス基板。
- 仕上げ研磨後のガラス基板の主面の5μm四方の表面粗さが0.30nm以下である、請求項4または5に記載の無アルカリガラス基板。
- 少なくとも1辺の長さが900mm以上である、請求項4~6のいずれか一項に記載の無アルカリガラス基板。
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WO2016199746A1 (ja) * | 2015-06-09 | 2016-12-15 | 旭硝子株式会社 | ガラス板及びガラス板の製造方法 |
JP2017145172A (ja) * | 2016-02-17 | 2017-08-24 | 旭硝子株式会社 | ガラス板、及びガラス板の製造方法 |
US10640416B2 (en) * | 2017-03-31 | 2020-05-05 | AGC Inc. | Alkali-free glass substrate |
EP3647283A1 (en) * | 2018-10-31 | 2020-05-06 | Agc Inc. | Optical material for light guide plates and light guide plate |
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CN105992749B (zh) * | 2013-11-28 | 2020-11-03 | Agc株式会社 | 无碱玻璃基板及无碱玻璃基板的减薄方法 |
JPWO2020162604A1 (ja) * | 2019-02-07 | 2021-12-09 | Agc株式会社 | 無アルカリガラス |
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EP3647283A1 (en) * | 2018-10-31 | 2020-05-06 | Agc Inc. | Optical material for light guide plates and light guide plate |
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