WO2019146379A1 - Glass substrate and method for manufacturing same - Google Patents

Glass substrate and method for manufacturing same Download PDF

Info

Publication number
WO2019146379A1
WO2019146379A1 PCT/JP2018/048458 JP2018048458W WO2019146379A1 WO 2019146379 A1 WO2019146379 A1 WO 2019146379A1 JP 2018048458 W JP2018048458 W JP 2018048458W WO 2019146379 A1 WO2019146379 A1 WO 2019146379A1
Authority
WO
WIPO (PCT)
Prior art keywords
glass substrate
glass
less
substrate according
content
Prior art date
Application number
PCT/JP2018/048458
Other languages
French (fr)
Japanese (ja)
Inventor
博通 梅村
Original Assignee
日本電気硝子株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日本電気硝子株式会社 filed Critical 日本電気硝子株式会社
Priority to KR1020207010355A priority Critical patent/KR102516142B1/en
Priority to CN201880087482.5A priority patent/CN111630010A/en
Priority to JP2019567947A priority patent/JP7256473B2/en
Publication of WO2019146379A1 publication Critical patent/WO2019146379A1/en

Links

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
    • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B25/00—Annealing glass products
    • C03B25/04—Annealing glass products in a continuous way
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B25/00—Annealing glass products
    • C03B25/04—Annealing glass products in a continuous way
    • C03B25/06—Annealing glass products in a continuous way with horizontal displacement of the glass products
    • C03B25/08—Annealing glass products in a continuous way with horizontal displacement of the glass products of glass sheets
    • 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
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C19/00—Surface treatment of glass, not in the form of fibres or filaments, by mechanical means
    • 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

Definitions

  • the present invention relates to a glass substrate suitable for a high definition display, and less likely to cause electrostatic charge even if peeled after contacting with other members, and a method of manufacturing the same.
  • glass is widely used as a substrate for flat panel displays such as liquid crystal displays, hard disks, filters, sensors and the like.
  • flat panel displays such as liquid crystal displays, hard disks, filters, sensors and the like.
  • high definition displays such as low temperature polysilicon TFTs and organic ELs have been actively developed, and some have already been put to practical use.
  • the following characteristics (1) to (5) are particularly required for the glass substrate used for the high definition display.
  • Low thermal shrinkage and excellent thermal stability That is, the glass substrate is heat-treated to several hundred degrees in steps such as film formation and annealing. During the heat treatment, when the glass substrate is thermally shrunk, pattern displacement or the like is likely to occur. For example, in the process of manufacturing a low temperature polysilicon TFT, a heat treatment process at 400 to 600 ° C. is present, and in this heat treatment process, the glass substrate is thermally shrunk to cause dimensional change.
  • Patent Document 1 proposes an alkali-free glass substrate suitable for a high definition display.
  • non-alkali glass substrate which does not contain an alkali metal oxide
  • electrostatic electrification may become a problem.
  • Glass which is originally an insulator, is very likely to be charged, but alkali-free glass is particularly likely to be charged, and static electricity once charged tends to be maintained without escape.
  • charging of the glass substrate is caused in various processes, but in the film forming process etc., the charging caused by peeling after contacting the glass substrate with the metal or insulator plate is peeling It is called electrification.
  • Peeling charging of a glass substrate occurs not only in atmospheric processes under normal pressure, but also in vacuum processes such as a process of etching a thin film on a substrate surface and a film forming process.
  • a discharge occurs.
  • the elements, the electrode lines on the surface of the glass substrate, or the glass substrate itself are destroyed by the discharge (dielectric breakdown or electrostatic breakdown), which causes a display defect.
  • dielectric breakdown or electrostatic breakdown causes a display defect.
  • liquid crystal displays particularly low temperature polysilicon TFT displays have minute semiconductor elements such as thin film transistors and electronic circuits formed on the surface of a glass substrate, but these elements and circuits are particularly problematic because they are very susceptible to electrostatic breakdown. It also attracts dust present in the charged environment and causes contamination of the substrate surface.
  • An object of the present invention is to provide a glass substrate which is suitable as a high definition display substrate due to its low thermal shrinkage and which is less likely to cause peeling charge.
  • the glass substrate of the present invention invented to solve the above-mentioned problems is, by mass percentage, SiO 2 50-70%, Al 2 O 3 10-25%, B 2 O 3 0% or more and less than 3%, MgO 0 ⁇ 10%, CaO 0 to 15%, SrO 0 to 10%, BaO 0 to 15%, Na 2 O 0.005 to 0.3%, ⁇ -OH value less than 0.18 / mm, strain It is characterized in that the point is 735 ° C. or higher.
  • the heat shrinkage rate decreases as the ⁇ -OH value decreases, but the alkali-free glass substrate is significantly easily charged when the ⁇ -OH value is less than 0.18 / mm. .
  • the glass substrate contains 0.005% by mass or more of Na 2 O, which has the effect of reducing the specific resistance of the glass. Can be suppressed.
  • the inclusion of Na 2 O and B 2 O 3 in a large amount of glass containing, B 2 O 3 in the glass during melting tends to volatilize as the sodium compound.
  • B 2 O 3 is regulated to less than 3% by mass, the volatilization of B 2 O 3 at the time of glass melting can be suppressed, and stabilization of the amount of Na 2 O in glass can be achieved. As a result, it is possible to stably obtain a glass substrate which has a low thermal shrinkage and is difficult to be charged.
  • Examples of the method for reducing the ⁇ -OH value of the glass substrate in the present invention include the following methods. (1) A glass batch with a low water content (a glass raw material with a low water content or a glass cullet obtained by finely grinding a glass body with a low water content) is selected. (2) Add components (Cl, SO 3, etc.) having the function of reducing the amount of water in the glass. (3) Decrease the amount of water in the furnace atmosphere. (4) N 2 bubbling is performed in the molten glass. (5) Adopt a small melting furnace. (6) Increase the flow rate of molten glass. (7) Adopt an electric melting furnace.
  • an electric melting furnace using a glass batch with a water content as low as possible from the viewpoint of lowering the ⁇ -OH value.
  • the electric melting furnace is preferably a complete electric melting furnace that does not use a burner, but may be an electric melting furnace equipped with a burner or a heater for performing additional radiant heating at the beginning of melting.
  • the thermal shrinkage of the glass substrate is preferably 20 ppm or less, 15 ppm or less, 12 ppm or less, 10 ppm or less, 9 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, particularly 5 ppm or less.
  • the thermal contraction rate of a glass substrate 0 ppm it is preferable to be 1 ppm or more, 2 ppm or more, particularly 3 ppm or more, because the productivity is significantly reduced.
  • the variation of the heat shrinkage rate of the glass substrate relative to the target value is preferably ⁇ 1.0 ppm or less, particularly preferably ⁇ 0.5 ppm or less.
  • the thermal contraction rate of the glass substrate is high, display defects of the low temperature polysilicon TFT and the display of the organic EL are easily generated, and when the variation of the thermal contraction rate of the glass substrate is large, the display substrate is stably produced.
  • the water content of the glass material may be adjusted or the cooling rate in the slow cooling process may be adjusted.
  • the method for forming a glass substrate according to the present invention is not particularly limited, but the float method is preferable from the viewpoint of prolonging the slow cooling process, and the surface quality of the glass substrate can be improved or its thickness is small.
  • the downdraw method in particular the overflow downdraw method, is preferred.
  • the overflow down draw method the surfaces to be the front and back surfaces of the glass substrate are not in contact with the molded body, and are molded in the state of free surface. For this reason, the center part of plate thickness direction is an overflow joint surface, and the glass substrate which both surfaces are fire-formed surfaces is obtained.
  • a glass substrate which is not polished and is excellent in surface quality (small surface roughness and waviness) can be manufactured at low cost.
  • the length (height difference) of the annealing furnace is preferably 3 m or more.
  • the slow cooling process is a process for removing the strain of the glass substrate.
  • the longer the slow cooling furnace the easier it is to adjust the cooling rate of the sheet glass and the smaller the thermal contraction rate of the glass substrate. Therefore, the length of the lehr is preferably 5 m or more, 6 m or more, 7 m or more, 8 m or more, 9 m or more, particularly 10 m or more.
  • the cooling rate of the sheet glass in the slow cooling step is 50 to 1000 ° C./min, 100 to 1000 ° C./min, 100 to 800 ° C. in the temperature range from the slow cooling point (slow cooling point -100 ° C.). It is preferable that the cooling rate per minute be 300 ° C./min to 800 ° C./min.
  • the thermal contraction rate of the glass substrate also fluctuates at the cooling rate when the plate glass is gradually cooled. That is, the glass substrate cooled rapidly has a high thermal contraction rate, and the glass substrate cooled slowly has a low thermal contraction rate.
  • the slowly cooled plate glass is subjected to a cutting process. That is, the formed plate-like glass (glass ribbon) is cut into a predetermined size. Thereafter, in order to prevent damage from the end face, end face grinding or end face polishing may be performed. It is preferable that the short side of the glass substrate thus obtained is 1500 mm or more and the long side is 1850 mm or more.
  • the short side is preferably 1950 mm or more, 2200 mm or more, 2800 mm or more, particularly 2950 mm or more
  • the long side is 2250 mm or more, 2500 mm or more, 3000 mm or more And particularly preferably 3400 mm or more.
  • the thickness of the glass substrate is preferably 0.7 mm or less, 0.6 mm or less, 0.5 mm or less, and particularly 0.4 mm or less.
  • the thickness is reduced, the weight of the glass substrate can be reduced, which is suitable for a mobile display substrate.
  • the thickness of the glass substrate is too small, it is likely to be damaged by peeling charge, and it is preferably 0.1 mm or more, more preferably 0.2 mm or more.
  • At least one surface is a fine uneven surface.
  • the surface roughness Ra may be 0.1 to 10 nm as the surface shape of the fine uneven surface.
  • a method for making the surface of the glass substrate a fine uneven surface physical etching using a polishing apparatus or chemical etching in which an etching solution is applied to the glass substrate or an etching gas is sprayed may be adopted. good. It is preferable to use the latter chemical etching because glass powder and the like are less likely to adhere to the glass substrate and the surface can be cleaned. Since the glass substrate of the present invention is originally unlikely to cause peeling charge, even when fine irregularities are formed on the surface, the processing time can be shortened and productivity can be improved.
  • the present invention it is possible to stably obtain a glass substrate which is suitable as a high definition display substrate due to its low thermal shrinkage and which is less likely to cause peeling charge.
  • a numerical range indicated using “to” means a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.
  • the glass substrate of the present invention is, by mass percentage, 50 to 70% SiO 2 , 10 to 25% Al 2 O 3 , 0 to 3% B 2 O 3 , 0 to 10% MgO, 0 to 15% CaO, It contains 0 to 10% of SrO, 0 to 15% of BaO, and 0.005 to 0.3% of Na 2 O.
  • the reason for restricting the content of each glass component as described above will be described below.
  • % indication of the following each component points to the mass% unless there is particular notice.
  • the chemical resistance in particular, the acid resistance tends to decrease, and the strain point tends to decrease.
  • the density is increased, which makes it difficult to reduce the weight of the glass substrate.
  • the density of the glass is preferably less than 2.70 g / cm 3 and even less than 2.65 g / cm 3 .
  • SiO 2 -based crystals in particular cristobalite, precipitate and the liquidus viscosity decreases, that is, the devitrification resistance tends to decrease.
  • SiO 2 is 50% or more, 55% or more, 58% or more, 60.5% or more, more preferably 61% or more, 70% or less, 65% or less, 64% or less, 63.5% or less, 63 % Or less, 62.5% or less, and more preferably 62% or less.
  • Al 2 O 3 is 10% or more, 13% or more, 15% or more, 16% or more, 17% or more, 17.5% or more, preferably 18% or more, and 25% or less, 23% or less, 21 % Or less, 20% or less, 19% or less, 19.7% or less, and further preferably 19.5% or less.
  • B 2 O 3 is a component that acts as a flux and reduces the viscosity to improve the meltability.
  • the content of B 2 O 3 increases, the molten glass is volatilized and the glass component tends to fluctuate. Further, as the content of B 2 O 3 increases, the strain point is lowered, and the heat resistance and the acid resistance are also easily lowered. Furthermore, the Young's modulus is lowered, and the deflection of the glass substrate tends to be large. Therefore, it is preferable that B 2 O 3 is not contained substantially less than 3%, 2% or less, 1.7% or less, 1.5% or less, 1.4% or less, 1% or less. However, B 2 O 3 is 0.1% or more, 0.2% or more, 0.3% or more, 0.4% or more from the viewpoint of improving the meltability and preventing the decrease in BHF resistance and crack resistance. Furthermore, 0.5% or more may be contained.
  • the ⁇ -OH value of the glass is susceptible to the moisture contained in the glass batch charged into the glass melting furnace, and in particular, the glass material serving as the boron source is hygroscopic and contains crystal water. Because there is also, it is easy to bring moisture into the glass. Therefore, as the content of B 2 O 3 in the glass decreases, the ⁇ -OH value of the glass tends to decrease. Further, as the ⁇ -OH value decreases, the strain point of the glass becomes higher, and it becomes easier to reduce the heat shrinkage of the glass substrate. From the above reasons, in the present invention, it is preferable to reduce B 2 O 3 as much as possible, and it is desirable not to substantially contain B 2 O 3 .
  • the substantially free of B 2 O 3, a means that does not contain B 2 O 3 as intentionally raw material, does not exclude the contamination from impurities. Specifically, it means that the content of B 2 O 3 is 0.1% or less.
  • MgO is a component that lowers the viscosity at high temperature to enhance the meltability, and among alkaline earth metal oxides is a component that significantly increases the Young's modulus, but when introduced in excess, SiO 2 -based crystals, especially cristobalite It precipitates and the liquidus viscosity tends to decrease. Furthermore, MgO is a component that easily reacts with BHF to form a product. When the content of MgO is reduced, it is difficult to receive the above effect, and when the content of MgO is increased, the devitrification resistance and the strain point are easily reduced.
  • the content of MgO is preferably 10% or less, 9% or less, 8% or less, 6% or less, 5% or less, 4% or less, 3.5% or less, particularly 3% or less. Further, it is preferably 1% or more and 1.5% or more, particularly 2% or more.
  • CaO is a component that lowers the high temperature viscosity and significantly enhances the meltability without reducing the strain point. Further, among the alkaline earth metal oxides, since the introduced material is relatively inexpensive, it is a component that reduces the cost of the material. When the content of CaO decreases, it becomes difficult to receive the above effects. On the other hand, when the content of CaO is too large, the glass is likely to be devitrified and the thermal expansion coefficient tends to be high. Therefore, the content of CaO is preferably 15% or less, 12% or less, 11% or less, 8% or less, particularly 6% or less. Further, it is preferably 1% or more, 2% or more, 3% or more, 4% or more, particularly 5% or more.
  • SrO is a component that suppresses the phase separation of glass and enhances the devitrification resistance. Furthermore, it is a component which suppresses the rise of liquidus temperature while lowering the high temperature viscosity and reducing the melting point without lowering the strain point.
  • the content of SrO decreases, it is difficult to receive the above effects.
  • the content of SrO is preferably 10% or less, 7% or less, 5% or less, 4% or less, particularly 3% or less. Further, 0.1% or more, 0.2% or more, 0.3% or more, 0.5% or more, 1.0% or more, particularly preferably 1.5% or more.
  • BaO is a component that significantly enhances the devitrification resistance.
  • the content of BaO decreases, it becomes difficult to receive the above effects.
  • the content of BaO increases, the density becomes too high and the meltability tends to be reduced.
  • devitrified crystals containing BaO are easily precipitated, and the liquidus temperature tends to rise. Therefore, the content of BaO is 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10.5% or less, 10% or less, 9.5% or less, particularly 9% or less Is preferred. Further, it is preferably 1% or more, 3% or more, 4% or more, 5% or more, 6% or more, particularly 7% or more.
  • Na 2 O is a component that reduces the specific resistance of glass. When the content of Na 2 O decreases, it is difficult to receive the above effects. On the other hand, when the content of Na 2 O is increased, alkali ions are diffused into the formed semiconductor substance at the time of heat treatment, resulting in deterioration of film properties. Therefore, Na 2 O is 0.005% or more, 0.008% or more, 0.01% or more, 0.02% or more, 0.025% or more, 0.03% or more, or 0.05% or more. Preferably, it is 0.3% or less, more preferably 0.2% or less.
  • K 2 O may be added as an alkali metal oxide other than Na 2 O.
  • K 2 O is also a component that reduces the specific resistance of glass. As the content of K 2 O decreases, it becomes difficult to receive the above effects. On the other hand, when the content of K 2 O is increased, alkali ions are diffused into the formed semiconductor substance during heat treatment, resulting in deterioration of film properties. Therefore, K 2 O is 0.001% or more, 0.002% or more, 0.005% or more, 0.01% or more, 0.02% or more, 0.025% or more, 0.035% or more, or more. 0.05% or more is preferable, 0.3% or less, further 0.2% or less is preferable. K 2 O can be contained more than Na 2 O.
  • the total amount of alkali metal oxides (Na 2 O, Li 2 The total amount of O and K 2 O) is preferably 0.4% or less.
  • the glass substrate of the present invention preferably contains 0.005 to 0.1% of Fe 2 O 3 .
  • Fe 2 O 3 is a component having the function of reducing the specific resistance of glass, and the effect of suppressing charging of the glass substrate is further enhanced by containing Fe 2 O 3 in a certain amount or more.
  • the Fe 2 O 3 content is preferably 0.005% or more, 0.008% or more, and particularly preferably 0.01% or more.
  • the content of Fe 2 O 3 is preferably 0.1% or less.
  • the glass substrate of the present invention preferably contains 0.001 to 0.5% of SnO 2 .
  • SnO 2 is a component that has a good fining action in the high temperature range, and increases the strain point and reduces the high temperature viscosity. In the case of an electric melting furnace using a molybdenum electrode, there is an advantage that the electrode is not corroded.
  • the content of SnO 2 increases, devitrified crystals of SnO 2 easily precipitate and it becomes easy to promote the precipitation of devitrified crystals of ZrO 2 . Therefore, the content of SnO 2 is 0.001 to 0.5%, 0.001 to 0.45%, 0.001 to 0.4%, 0.01 to 0.35%, 0.1 to 0. It is preferably 3%, particularly 0.15 to 0.3%.
  • ZnO is a component that enhances the meltability. However, when the content of ZnO is increased, the glass is likely to be devitrified and the strain point is easily reduced.
  • the content of ZnO is preferably 0 to 5%, 0 to 4%, 0 to 3%, particularly 0 to 2%.
  • ZrO 2 is a component that enhances chemical durability, but when the content of ZrO 2 is large, devitrification of ZrSiO 4 tends to occur.
  • the content of ZrO 2 is preferably 0 to 5%, 0 to 4%, 0 to 3%, particularly 0.01 to 2%.
  • TiO 2 is a component that lowers high-temperature viscosity to enhance meltability and suppresses coloring due to solarization, but if the content of TiO 2 is large, the glass becomes colored and the transmittance tends to be reduced.
  • the content of TiO 2 is preferably 0 to 5%, 0 to 4%, 0 to 3%, 0 to 2%, particularly 0 to 0.1%.
  • P 2 O 5 is a component that enhances the strain point and suppresses the precipitation of devitrified crystals of an alkaline earth aluminosilicate system such as anorthite. However, when a large amount of P 2 O 5 is contained, the phase separation of the glass is facilitated.
  • the content of P 2 O 5 is preferably 0 to less than 0.15%, 0 to 1%, or 0 to 0.1%, and in particular, does not substantially contain it in terms of facilitating glass recycling. Specifically, it is desirable to be less than 0.01%.
  • Metal powders such as Cl, F, SO 3 , C, CeO 2 or Al, Si can be contained up to 3% in total.
  • As 2 O 3 and Sb 2 O 3 are useful as a fining agent, but it is desirable not to contain substantially from the viewpoint of preventing the environment and erosion of the electrode.
  • “not substantially contained” means that the total amount of As 2 O 3 and Sb 2 O 3 is 0.1% or less.
  • the glass substrate of the present invention has a ⁇ -OH value of less than 0.18 / mm.
  • the ⁇ -OH value is preferably 0.01 / mm or more, 0.02 / mm or more, and particularly preferably 0.03 / mm or more.
  • the strain point of the glass substrate of the present invention is 735 ° C. or more.
  • the strain point is preferably 800 ° C. or less.
  • the glass substrate of the present invention preferably has an annealing point of 780 ° C. or more, 790 ° C. or more, 800 ° C. or more, 810 ° C. or more, particularly 820 ° C. or more, for the same reason as the strain point.
  • the annealing temperature is preferably 850 ° C. or less, more preferably 840 ° C. or less .
  • the glass substrate of the present invention preferably has a Young's modulus of 80 GPa or more.
  • the Young's modulus is preferably 81 GPa or more, 82 GPa or more, 83 GPa or more, 84 GPa or more, and more preferably 85 GPa or more.
  • the glass substrate of the present invention preferably has a temperature corresponding to 10 4.5 dPa ⁇ s of 1330 ° C. or less, 1320 ° C. or less, and particularly 1310 ° C. or less.
  • a temperature corresponding to 10 4.5 dPa ⁇ s becomes high, the temperature at the time of molding becomes too high, and the production yield tends to be lowered.
  • the glass substrate of the present invention preferably has a temperature corresponding to 10 2.5 dPa ⁇ s of 1670 ° C. or less, 1660 ° C. or less, particularly 1650 ° C. or less.
  • a temperature corresponding to 10 2.5 dPa ⁇ s becomes high, the glass becomes difficult to melt, defects such as bubbles increase, and the production yield tends to decrease.
  • the glass substrate of the present invention preferably has a liquidus temperature of less than 1250 ° C., less than 1240 ° C., less than 1230 ° C., and particularly less than 1220 ° C.
  • a liquidus temperature of less than 1250 ° C., less than 1240 ° C., less than 1230 ° C., and particularly less than 1220 ° C.
  • the glass substrate of the present invention has a viscosity at a liquidus temperature of 10 4.9 dPa ⁇ s or more, 10 5.0 dPa ⁇ s 10 5.1 dPa ⁇ s or more, 10 5.2 dPa ⁇ s or more, in particular 10 5. It is preferably 3 dPa ⁇ s or more. In this way, devitrification is less likely to occur at the time of glass forming, so it becomes easy to form in a plate shape by the overflow down draw method, and the surface quality of the glass substrate can be improved.
  • the viscosity at the liquidus temperature is an index of formability, and the formability improves as the viscosity at the liquidus temperature is higher.
  • Example 1 Tables 1 and 2 show example glasses of the present invention (samples No. 1 to 9) and conventional glasses (sample No. 10). The contents of the components other than Na 2 O, K 2 O, Fe 2 O 3 , and ZrO 2 in the table are rounded off to one decimal place.
  • the glass samples in Tables 1 and 2 were prepared as follows. First, a glass batch prepared by preparing glass raw materials to have the composition shown in the table was put into a platinum crucible and melted at 1600 to 1650 ° C. for 24 hours. In melting the glass batch, it was stirred using a platinum stirrer and homogenized. Next, the molten glass was poured out on a carbon plate and formed into a plate, and then annealed for 30 minutes at a temperature near the annealing point.
  • strain point For each sample thus obtained, strain point, annealing point, density, Young's modulus, temperature corresponding to 10 4.5 dPa ⁇ s, temperature corresponding to 10 2.5 dPa ⁇ s, liquidus temperature TL, liquid Log 10 ⁇ TL was measured for viscosity TL TL (dPa ⁇ s) at the phase temperature.
  • strain points and annealing points in Tables 1 and 2 were measured by the method of ASTM C336.
  • the density was measured by Archimedes method according to ASTM C693.
  • Young's modulus was measured by a bending resonance method according to JIS R1602.
  • the temperatures corresponding to 10 4.5 dPa ⁇ s and 10 2.5 dPa ⁇ s were measured by a platinum ball pulling method.
  • the liquidus temperature TL passes through a standard sieve of 30 mesh (500 ⁇ m), and the glass powder remaining on 50 mesh (300 ⁇ m) is charged into a platinum boat and held for 24 hours in a temperature gradient furnace set at 1100 ° C. to 1350 ° C. After that, the platinum boat was taken out, and the temperature at which devitrification (crystal foreign matter) was observed in the glass was measured.
  • the viscosity Log 10 ⁇ TL at the liquidus temperature was measured by measuring the viscosity ⁇ TL of the glass at the liquidus temperature by a platinum ball pulling method, and the Log 10 ⁇ TL was calculated.
  • ⁇ -OH value (1 / X) log (T1 / T2)
  • X Glass thickness (mm)
  • T1 transmittance at a reference wavelength 3846 cm -1 (%)
  • T2 Minimum transmittance in the vicinity of the hydroxyl group absorption wavelength 3600 cm -1 (%)
  • each of the samples No. 1 to No. 9 is a glass which tends to have a thermal shrinkage of 20 ppm or less because the strain point is 735 ° C. or more and the slow cooling point is 785 ° C. or more. Further, since the Young's modulus is 80.4 GPa or more, it is difficult to bend, and since the liquid phase temperature TL is 1246 ° C. or less and the viscosity TLTL at the liquid phase temperature is 10 4.9 dPa ⁇ s or more, devitrification hardly occurs during molding. . In particular, no. Each of the samples 1, 2 and 7 to 9 was suitable for the overflow down draw method because the viscosity ⁇ TL at the liquidus temperature was 10 5.2 dPa ⁇ s or more.
  • Example 2 Sample No. in Table 2 Glass batches were prepared to be 8 and 10 glasses. Next, the glass batch was put into an electric melting furnace, melted at 1600 to 1650 ° C., and then the molten glass was clarified and homogenized in a clarification tank and a homogenization tank, and then adjusted to a viscosity suitable for molding in a pot. . Next, the molten glass is formed into a plate shape by an overflow downdraw apparatus, and the average cooling rate in the temperature range from the annealing point to (annealing point -100 ° C) is set to 385 ° C / min in a 5-m long annealing furnace. Then it was slowly cooled. Thereafter, the plate-like glass was cut and edge-processed to prepare a glass substrate having dimensions of 1500 ⁇ 1850 ⁇ 0.7 mm.
  • the ⁇ -OH value and the thermal contraction rate of each glass substrate thus obtained were measured.
  • the ⁇ -OH value of the glass substrate of No. 8 was 0.1 / mm, and the thermal shrinkage was 10 ppm.
  • the ⁇ -OH value of the 10 glass substrates was 0.3 / mm, and the thermal shrinkage was 25 ppm.
  • the thermal contraction rate of the glass substrate was measured by the following method. First, as shown in FIG. 1A, a strip-shaped sample G of 160 mm ⁇ 30 mm was prepared as a sample of a glass substrate. A marking M was formed on each of both ends in the long side direction of the strip-like sample G using a water-resistant abrasive paper of # 1000 at a distance of 20 to 40 mm from the edge. Thereafter, as shown in FIG. 1B, the strip-like sample G on which the marking M was formed was broken into two along the direction orthogonal to the marking M to produce sample pieces Ga and Gb. Then, only one of the sample pieces Gb was heated from normal temperature (25 ° C.) to 500 ° C.
  • the support base 1 of the glass substrate G is provided with pads 2 made of Teflon (registered trademark) for supporting the four corners of the glass substrate G.
  • the support base 1 is provided with a table 3 made of metal aluminum which can be moved up and down, and after bringing the table 3 into contact with the glass substrate G by moving the table 3 up and down as shown in FIG. By peeling the glass substrate G, the glass substrate G can be charged.
  • the table 3 is grounded. Further, one or more holes (not shown) are formed in the table 3, and the holes are connected to a diamond-shaped vacuum pump (not shown). When the vacuum pump is driven, air is sucked from the holes of the table 3, whereby the glass substrate G can be vacuum adsorbed to the table 3.
  • a surface voltmeter 4 is installed at a position 10 mm above the glass substrate G, by which the amount of charge generated at the central portion of the glass substrate G is continuously measured.
  • an air gun 5 with an ionizer is installed above the glass substrate G, whereby the charging of the glass substrate G can be eliminated.
  • the peeling charge of the glass substrate was measured in the next step using this apparatus.
  • the experiment was conducted in a clean booth at a temperature of 25 ° C. and a humidity of 40%. Since the amount of charge changes greatly under the influence of the atmosphere, particularly the humidity in the atmosphere, it is particularly necessary to adjust the humidity.
  • the glass substrate G is placed on the support pad 2 of the support 1.
  • the glass substrate G is discharged by an air gun 5 with an ionizer.
  • the table 3 is raised and brought into contact with the glass substrate G, and vacuum suction is carried out to bring the table 3 and the glass substrate G into close contact for 20 seconds.
  • the table 3 is lowered to separate the glass substrate G from the table 3, and the amount of charge generated at the central portion of the glass substrate G is continuously measured by the surface voltmeter 4.
  • a total of five peel evaluations are continuously performed by repeating the steps (3) and (4). The maximum charge amount in each measurement is determined, and these are integrated to obtain a peeling charge amount.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Mechanical Engineering (AREA)
  • Glass Compositions (AREA)
  • Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)
  • Surface Treatment Of Glass (AREA)

Abstract

The present invention addresses the technical problem of providing: a glass substrate which, because of having a small heat shrinkage rate, is suitable for a high-definition display substrate and which is unlikely to induce charge detachment; and a method for manufacturing such a glass substrate. The glass substrate according to the present invention is characterized by comprising, by mass percentage, 50-70% of SiO2, 10-25% of Al2O3, at least 0% but less than 3% of B2O3, 0-10% of MgO, 0-15% of CaO, 0-10% of SrO, 0-15% of BaO, and 0.005-0.3% of Na2O, and having a β-OH value of less than 0.18/mm and a strain point of at least 735°C.

Description

ガラス基板及びその製造方法Glass substrate and method of manufacturing the same
　本発明は、高精細のディスプレイに好適であり、他の部材と接触させた後で剥離しても静電気の帯電を引き起こしにくいガラス基板及びその製造方法に関するものである。 The present invention relates to a glass substrate suitable for a high definition display, and less likely to cause electrostatic charge even if peeled after contacting with other members, and a method of manufacturing the same.
　従来から液晶ディスプレイ等のフラットパネルディスプレイ、ハードディスク、フィルター、センサー等の基板として、ガラスが広く使用されている。近年では、従来の液晶ディスプレイに加えて、低温ポリシリコンＴＦＴや有機ＥＬといった高精細のディスプレイが盛んに開発され、一部では既に実用化されている。 Conventionally, glass is widely used as a substrate for flat panel displays such as liquid crystal displays, hard disks, filters, sensors and the like. In recent years, in addition to conventional liquid crystal displays, high definition displays such as low temperature polysilicon TFTs and organic ELs have been actively developed, and some have already been put to practical use.
　高精細のディスプレイに用いられるガラス基板には、特に次の（１）～（５）の特性が要求される。 The following characteristics (1) to (5) are particularly required for the glass substrate used for the high definition display.
　（１）無アルカリガラスであること。すなわちガラス基板中のアルカリ金属酸化物の含有量が多いと、熱処理時にアルカリイオンが成膜された半導体物質中に拡散し、膜の特性の劣化を招く。
　（２）熱収縮率が低く、熱安定性に優れていること。すなわちガラス基板は、成膜、アニール等の工程で数百度に熱処理される。熱処理の際に、ガラス基板が熱収縮すると、パターンズレ等が発生しやすくなる。例えば低温ポリシリコンＴＦＴの製造工程では４００～６００℃の熱処理工程が存在し、この熱処理工程でガラス基板が熱収縮し、寸法変化が生じる。この寸法変化が大きいと、ＴＦＴの画素ピッチにズレが生じ、表示不良の原因となる。また有機ＥＬの場合、わずかな寸法変化でも表示不良となる虞れがあり、熱収縮率の極めて低いガラス基板が要求されている。
　（３）ガラス基板の撓みに起因する不具合を抑制するため、ヤング率や比ヤング率が高いこと。
　（４）ガラスの製造の観点から、溶融性や耐失透性に優れていること。
　（５）ディスプレイの製造工程で要求される耐薬品性やエッチング性能を有すること。 (1) It is non-alkali glass. That is, when the content of the alkali metal oxide in the glass substrate is large, alkali ions are diffused into the formed semiconductor substance during heat treatment, resulting in deterioration of film characteristics.
(2) Low thermal shrinkage and excellent thermal stability. That is, the glass substrate is heat-treated to several hundred degrees in steps such as film formation and annealing. During the heat treatment, when the glass substrate is thermally shrunk, pattern displacement or the like is likely to occur. For example, in the process of manufacturing a low temperature polysilicon TFT, a heat treatment process at 400 to 600 ° C. is present, and in this heat treatment process, the glass substrate is thermally shrunk to cause dimensional change. If this dimensional change is large, a shift occurs in the pixel pitch of the TFT, which causes a display defect. In the case of an organic EL, even a slight dimensional change may result in display failure, and a glass substrate having a very low thermal shrinkage is required.
(3) A high Young's modulus or a specific Young's modulus in order to suppress a defect due to the bending of the glass substrate.
(4) From the viewpoint of glass production, it is excellent in meltability and devitrification resistance.
(5) Having chemical resistance and etching performance required in the display manufacturing process.
　特許文献１には、高精細のディスプレイに適した無アルカリガラス基板が提案されている。 Patent Document 1 proposes an alkali-free glass substrate suitable for a high definition display.
特開２０１６－１８３０９１号公報JP, 2016-183091, A
　上記したようにディスプレイに用いられるガラス基板には、アルカリ金属酸化物を含有しない無アルカリガラス基板が使用されているが、静電気の帯電が問題になることがある。もともと絶縁体であるガラスは非常に帯電しやすいが、無アルカリガラスは、特に帯電しやすく、一旦帯電した静電気が逃げずに維持される傾向がある。液晶ディスプレイなどの製造工程において、ガラス基板の帯電は様々な工程で引き起こされるが、成膜工程などにおいてガラス基板を金属や絶縁体のプレートと接触させた後、剥離することで起こる帯電は、剥離帯電と呼ばれる。ガラス基板の剥離帯電は、常圧の大気中の工程はもちろんのこと、基板表面の薄膜のエッチングを行う工程や成膜工程など、真空の工程中でも発生する。帯電したガラス基板に導電性の物質が近づくと放電が起こる。そして帯電している静電気の電圧は数１０ｋＶにも達するため、放電によってガラス基板表面の素子や電極線、あるいはガラス基板そのものの破壊（絶縁破壊あるいは静電破壊）が起こり、表示不良の原因となる。液晶ディスプレイの中でも特に低温ポリシリコンＴＦＴディスプレイは、ガラス基板表面に薄膜トランジスタなどの微細な半導体素子や電子回路が形成されるが、この素子や回路は静電破壊に非常に弱いため特に問題となる。また帯電した環境中に存在するダストを引き寄せて基板表面の汚染の原因ともなる。 Although the non-alkali glass substrate which does not contain an alkali metal oxide is used for the glass substrate used for a display as mentioned above, electrostatic electrification may become a problem. Glass, which is originally an insulator, is very likely to be charged, but alkali-free glass is particularly likely to be charged, and static electricity once charged tends to be maintained without escape. In the manufacturing process of liquid crystal displays etc., charging of the glass substrate is caused in various processes, but in the film forming process etc., the charging caused by peeling after contacting the glass substrate with the metal or insulator plate is peeling It is called electrification. Peeling charging of a glass substrate occurs not only in atmospheric processes under normal pressure, but also in vacuum processes such as a process of etching a thin film on a substrate surface and a film forming process. When a conductive substance approaches the charged glass substrate, a discharge occurs. Then, since the voltage of electrostatic charge reaches several tens of kV, the elements, the electrode lines on the surface of the glass substrate, or the glass substrate itself are destroyed by the discharge (dielectric breakdown or electrostatic breakdown), which causes a display defect. . Among liquid crystal displays, particularly low temperature polysilicon TFT displays have minute semiconductor elements such as thin film transistors and electronic circuits formed on the surface of a glass substrate, but these elements and circuits are particularly problematic because they are very susceptible to electrostatic breakdown. It also attracts dust present in the charged environment and causes contamination of the substrate surface.
　ガラス基板の帯電防止策としてはイオナイザを用いて電荷を中和する、あるいは環境中の温度を上げ、蓄積した電荷を空中に放電させる方法などがよく知られている。しかし、これらの対策はコストアップの要因になる他、工程中に帯電を引き起こす場所が多岐にわたるため、効果的な対策を打つことが難しいという問題が残る。さらにプラズマプロセスのような真空プロセス中ではこれらの手段を用いることができない。従って液晶ディスプレイを初めとするフラットパネルディスプレイ用途には、帯電しにくいガラス基板が強く求められている。 As a charge prevention measure of a glass substrate, a method of neutralizing charges using an ionizer or raising the temperature in the environment and discharging accumulated charges into the air is well known. However, these measures cause cost increase, and there are various places causing electrification in the process, so there remains a problem that it is difficult to take effective measures. Furthermore, these means can not be used in vacuum processes such as plasma processes. Therefore, in flat panel display applications including liquid crystal displays, a glass substrate that is difficult to charge is strongly required.
　本発明は、熱収縮率が低いため、高精細のディスプレイ基板として好適であり、剥離帯電を引き起こしにくいガラス基板を提供することを技術的課題とする。 An object of the present invention is to provide a glass substrate which is suitable as a high definition display substrate due to its low thermal shrinkage and which is less likely to cause peeling charge.
　上記課題を解決するために創案された本発明のガラス基板は、質量百分率で、ＳｉＯ２　５０～７０％、Ａｌ２Ｏ３　１０～２５％、Ｂ２Ｏ３　０％以上３％未満、ＭｇＯ　０～１０％、ＣａＯ　０～１５％、ＳｒＯ　０～１０％、ＢａＯ　０～１５％、Ｎａ２Ｏ　０．００５～０．３％を含有し、β－ＯＨ値が０．１８／ｍｍ未満、歪点が７３５℃以上であることを特徴とする。 The glass substrate of the present invention invented to solve the above-mentioned problems is, by mass percentage, SiO 2 50-70%, Al 2 O 3 10-25%, B 2 O 3 0% or more and less than 3%, MgO 0 ～ 10%, CaO 0 to 15%, SrO 0 to 10%, BaO 0 to 15%, Na 2 O 0.005 to 0.3%, β-OH value less than 0.18 / mm, strain It is characterized in that the point is 735 ° C. or higher.
　また本発明のガラス基板の製造方法は、質量百分率で、ＳｉＯ２　５０～７０％、Ａｌ２Ｏ３　１０～２５％、Ｂ２Ｏ３　０％以上３％未満、ＭｇＯ　０～１０％、ＣａＯ　０～１５％、ＳｒＯ　０～１０％、ＢａＯ　０～１５％、Ｎａ２Ｏ　０．００５～０．３％を含有するガラスとなるように調製されたガラスバッチを準備する原料準備工程、ガラスバッチを電気溶融炉で溶融する溶融工程、溶融ガラスを板状に成形する成形工程、板状のガラスを徐冷炉で徐冷する徐冷工程、徐冷した板状ガラスを所定寸法に切断する加工工程を含み、β－ＯＨ値が０．１８／ｍｍ未満、歪点が７３５℃以上のガラス基板を得ることを特徴とする。 In the method for producing a glass substrate according to the present invention, SiO 2 50 to 70%, Al 2 O 3 10 to 25%, B 2 O 3 0% to 3%, MgO 0 to 10%, CaO 0 in mass percentage. A raw material preparation step of preparing a glass batch prepared to be a glass containing ̃15%, SrO 0 ̃10%, BaO 0 ̃15%, Na 2 O 0.005 ̃0.3%, Including a melting step of melting in an electric melting furnace, a forming step of forming molten glass into a plate shape, a slow cooling step of gradually cooling a plate-like glass in a slow cooling furnace, and a processing step of cutting the slowly cooled plate glass to predetermined dimensions It is characterized in that a glass substrate having a β-OH value of less than 0.18 / mm and a strain point of 735 ° C. or more is obtained.
　本発明者の知見によると、無アルカリガラス基板は、β－ＯＨ値が低下するほど熱収縮率は低下するが、β－ＯＨ値が０．１８／ｍｍ未満になると、顕著に帯電しやすくなる。本発明によれば、β－ＯＨ値が０．１８／ｍｍ未満であるにもかかわらず、ガラスの比抵抗を低下させる作用を有するＮａ２Ｏを０．００５質量％以上含有するため、ガラス基板の帯電を抑制することが可能である。一方、Ｂ２Ｏ３を多量に含有するガラスにＮａ２Ｏを含有させると、ガラス溶融時にＢ２Ｏ３がナトリウム化合物として揮発しやすくなる。そのため本発明では、Ｂ２Ｏ３を３質量％未満に規制しており、ガラス溶融時におけるＢ２Ｏ３の揮発を抑え、ガラス中のＮａ２Ｏ量の安定化を図ることができる。これによって熱収縮率が低く、帯電しにくいガラス基板を安定して得ることが可能となる。 According to the findings of the present inventor, the heat shrinkage rate decreases as the β-OH value decreases, but the alkali-free glass substrate is significantly easily charged when the β-OH value is less than 0.18 / mm. . According to the present invention, although the β-OH value is less than 0.18 / mm, the glass substrate contains 0.005% by mass or more of Na 2 O, which has the effect of reducing the specific resistance of the glass. Can be suppressed. On the other hand, the inclusion of Na 2 O and B 2 O 3 in a large amount of glass containing, B 2 O 3 in the glass during melting tends to volatilize as the sodium compound. Therefore, in the present invention, B 2 O 3 is regulated to less than 3% by mass, the volatilization of B 2 O 3 at the time of glass melting can be suppressed, and stabilization of the amount of Na 2 O in glass can be achieved. As a result, it is possible to stably obtain a glass substrate which has a low thermal shrinkage and is difficult to be charged.
　なお、「β－ＯＨ値」は、ＦＴ－ＩＲを用いてガラスの透過率を測定し、下記の式を用いて求めた値を指す。
　β－ＯＨ値　＝　（１／Ｘ）ｌｏｇ（Ｔ１／Ｔ２）
　Ｘ：ガラス肉厚（ｍｍ）
　Ｔ１：参照波長３８４６ｃｍ－１における透過率（％）
　Ｔ２：水酸基吸収波長３６００ｃｍ－１付近における最小透過率（％） The “β-OH value” refers to a value obtained by measuring the transmittance of glass using FT-IR and using the following equation.
β-OH value = (1 / X) log (T1 / T2)
X: Glass thickness (mm)
T1: transmittance at a reference wavelength 3846 cm -1 (%)
T2: Minimum transmittance in the vicinity of the hydroxyl group absorption wavelength 3600 cm -1 (%)
　本発明においてガラス基板のβ－ＯＨ値を低下させる方法としては、以下の方法が挙げられる。（１）含水量の低いガラスバッチ（含水量の少ないガラス原料や、含水量の少ないガラス体を細かく粉砕したガラスカレット）を選択する。（２）ガラス中の水分量を減少させる作用を有する成分（Ｃｌ、ＳＯ３など）を添加する。（３）炉内雰囲気中の水分量を低下させる。（４）溶融ガラス中でＮ２バブリングを行う。（５）小型溶融炉を採用する。（６）溶融ガラスの流量を大きくする。（７）電気溶融炉を採用する。 Examples of the method for reducing the β-OH value of the glass substrate in the present invention include the following methods. (1) A glass batch with a low water content (a glass raw material with a low water content or a glass cullet obtained by finely grinding a glass body with a low water content) is selected. (2) Add components (Cl, SO 3, etc.) having the function of reducing the amount of water in the glass. (3) Decrease the amount of water in the furnace atmosphere. (4) N 2 bubbling is performed in the molten glass. (5) Adopt a small melting furnace. (6) Increase the flow rate of molten glass. (7) Adopt an electric melting furnace.
　上記したように本発明のガラス基板を製造する場合、β－ＯＨ値を低下するという観点から、できるだけ含水量の低いガラスバッチを使用し、電気溶融炉を用いることが好ましい。電気溶融炉を用いてガラスバッチを溶融する場合、溶融炉内におけるガス燃焼等に起因する雰囲気の水分量の上昇が抑えられるため、ガス燃焼炉に比べて溶融ガラス中の水分量を低減しやすい。そのため電気溶融炉で製造したガラスは、β－ＯＨ値が低下する。またβ－ＯＨ値が低下するほど、ガラスの歪点が高くなり、熱収縮率の低いガラス基板が得られやすくなる。電気溶融炉は、バーナーを用いない完全電気溶融炉であることが望ましいが、溶融初期において補助的に輻射加熱を行うためのバーナーやヒーターを備えた電気溶融炉であっても良い。 As described above, when producing the glass substrate of the present invention, it is preferable to use an electric melting furnace using a glass batch with a water content as low as possible from the viewpoint of lowering the β-OH value. When melting a glass batch using an electric melting furnace, it is easy to reduce the water content in the molten glass compared to a gas combustion furnace because the increase in the water content of the atmosphere caused by gas combustion and the like in the melting furnace is suppressed. . Therefore, the glass produced by the electric melting furnace has a lowered β-OH value. Further, as the β-OH value decreases, the strain point of the glass becomes higher, and a glass substrate having a low thermal contraction rate can be easily obtained. The electric melting furnace is preferably a complete electric melting furnace that does not use a burner, but may be an electric melting furnace equipped with a burner or a heater for performing additional radiant heating at the beginning of melting.
　本発明において、ガラス基板の熱収縮率が２０ｐｐｍ以下、１５ｐｐｍ以下、１２ｐｐｍ以下、１０ｐｐｍ以下、９ｐｐｍ以下、８ｐｐｍ以下、７ｐｐｍ以下、６ｐｐｍ以下、特に５ｐｐｍ以下であることが好ましい。ただしガラス基板の熱収縮率を０ｐｐｍにするには、生産性の著しい低下を伴うため、１ｐｐｍ以上、２ｐｐｍ以上、特に３ｐｐｍ以上であることが好ましい。またガラス基板の熱収縮率の目標値に対するばらつきは±１．０ｐｐｍ以下、特に±０．５ｐｐｍ以下であることが好ましい。ガラス基板の熱収縮率が高いと、低温ポリシリコンＴＦＴや有機ＥＬのディスプレイの表示不良が発生しやすくなり、またガラス基板の熱収縮率のばらつきが大きいと、ディスプレイ基板を安定して生産することができなくなる。ガラス基板の熱収縮率のばらつきを小さくするためには、ガラス原料の水分量を調整したり、徐冷工程の冷却速度を調整すれば良い。 In the present invention, the thermal shrinkage of the glass substrate is preferably 20 ppm or less, 15 ppm or less, 12 ppm or less, 10 ppm or less, 9 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, particularly 5 ppm or less. However, in order to make the thermal contraction rate of a glass substrate 0 ppm, it is preferable to be 1 ppm or more, 2 ppm or more, particularly 3 ppm or more, because the productivity is significantly reduced. Further, the variation of the heat shrinkage rate of the glass substrate relative to the target value is preferably ± 1.0 ppm or less, particularly preferably ± 0.5 ppm or less. When the thermal contraction rate of the glass substrate is high, display defects of the low temperature polysilicon TFT and the display of the organic EL are easily generated, and when the variation of the thermal contraction rate of the glass substrate is large, the display substrate is stably produced. Can not In order to reduce the variation in the thermal contraction rate of the glass substrate, the water content of the glass material may be adjusted or the cooling rate in the slow cooling process may be adjusted.
　本発明のガラス基板の成形方法は、特に制限されるものではないが、徐冷工程を長くできるという観点からはフロート法が好ましく、またガラス基板の表面品位の向上を図ったり、その厚みを小さくするという観点からは、ダウンドロー法、特にオーバーフローダウンドロー法が好ましい。オーバーフローダウンドロー法では、ガラス基板の表裏面となるべき面が成形体に接触せず、自由表面の状態で成形される。このため板厚方向の中央部がオーバーフロー合流面であり、両表面が火造り面であるガラス基板が得られる。これにより未研磨で表面品位に優れた（表面粗さやうねりが小さい）ガラス基板を安価に製造することができる。 The method for forming a glass substrate according to the present invention is not particularly limited, but the float method is preferable from the viewpoint of prolonging the slow cooling process, and the surface quality of the glass substrate can be improved or its thickness is small. From the point of view, the downdraw method, in particular the overflow downdraw method, is preferred. In the overflow down draw method, the surfaces to be the front and back surfaces of the glass substrate are not in contact with the molded body, and are molded in the state of free surface. For this reason, the center part of plate thickness direction is an overflow joint surface, and the glass substrate which both surfaces are fire-formed surfaces is obtained. Thus, a glass substrate which is not polished and is excellent in surface quality (small surface roughness and waviness) can be manufactured at low cost.
　本発明において、ダウンドロー法を採用する場合、徐冷炉の長さ（高低差）は３ｍ以上であることが好ましい。徐冷工程は、ガラス基板の歪を除去するための工程であるが、徐冷炉が長いほど、板状ガラスの冷却速度を調整しやすく、ガラス基板の熱収縮率を小さくすることが容易となる。よって徐冷炉の長さは、５ｍ以上、６ｍ以上、７ｍ以上、８ｍ以上、９ｍ以上、特に１０ｍ以上であることが好ましい。 In the present invention, when the down draw method is employed, the length (height difference) of the annealing furnace is preferably 3 m or more. The slow cooling process is a process for removing the strain of the glass substrate. However, the longer the slow cooling furnace, the easier it is to adjust the cooling rate of the sheet glass and the smaller the thermal contraction rate of the glass substrate. Therefore, the length of the lehr is preferably 5 m or more, 6 m or more, 7 m or more, 8 m or more, 9 m or more, particularly 10 m or more.
　本発明において、徐冷工程における板状ガラスの冷却速度が、徐冷点から（徐冷点－１００℃）の温度範囲で５０～１０００℃／分、１００～１０００℃／分、１００～８００℃／分、３００℃／分～８００℃／分の平均冷却速度であることが好ましい。ガラス基板の熱収縮率は、板状ガラスを徐冷する時の冷却速度でも変動する。すなわち速く冷却されたガラス基板は、熱収縮率が高くなり、逆にゆっくり冷却されたガラス基板は、熱収縮率が低くなる。 In the present invention, the cooling rate of the sheet glass in the slow cooling step is 50 to 1000 ° C./min, 100 to 1000 ° C./min, 100 to 800 ° C. in the temperature range from the slow cooling point (slow cooling point -100 ° C.). It is preferable that the cooling rate per minute be 300 ° C./min to 800 ° C./min. The thermal contraction rate of the glass substrate also fluctuates at the cooling rate when the plate glass is gradually cooled. That is, the glass substrate cooled rapidly has a high thermal contraction rate, and the glass substrate cooled slowly has a low thermal contraction rate.
　本発明において、徐冷した板状ガラスには切断加工が施される。すなわち成形された板状のガラス（ガラスリボン）を所定寸法に切断する。その後、端面部からの破損を防止するため、端面研削加工や端面研磨加工を施してもよい。こうして得られるガラス基板の短辺は１５００ｍｍ以上、長辺は１８５０ｍｍ以上であることが好ましい。すなわちガラス基板の寸法が大きくなるほど、ガラス基板の生産効率が向上するため、その短辺は、１９５０ｍｍ以上、２２００ｍｍ以上、２８００ｍｍ以上、特に２９５０ｍｍ以上が好ましく、長辺は２２５０ｍｍ以上、２５００ｍｍ以上、３０００ｍｍ以上、特に３４００ｍｍ以上であることが好ましい。 In the present invention, the slowly cooled plate glass is subjected to a cutting process. That is, the formed plate-like glass (glass ribbon) is cut into a predetermined size. Thereafter, in order to prevent damage from the end face, end face grinding or end face polishing may be performed. It is preferable that the short side of the glass substrate thus obtained is 1500 mm or more and the long side is 1850 mm or more. That is, since the production efficiency of the glass substrate is improved as the size of the glass substrate is increased, the short side is preferably 1950 mm or more, 2200 mm or more, 2800 mm or more, particularly 2950 mm or more, and the long side is 2250 mm or more, 2500 mm or more, 3000 mm or more And particularly preferably 3400 mm or more.
　本発明において、ガラス基板の厚みは０．７ｍｍ以下、０．６ｍｍ以下、０．５ｍｍ以下、特に０．４ｍｍ以下であることが好ましい。厚みを小さくするほどガラス基板の軽量化を図ることができ、モバイル型ディスプレイ基板に好適となる。ただしガラス基板の厚みが小さくなりすぎると、剥離帯電により破損しやすくなるため、０．１ｍｍ以上、さらには０．２ｍｍ以上が好ましい。 In the present invention, the thickness of the glass substrate is preferably 0.7 mm or less, 0.6 mm or less, 0.5 mm or less, and particularly 0.4 mm or less. As the thickness is reduced, the weight of the glass substrate can be reduced, which is suitable for a mobile display substrate. However, if the thickness of the glass substrate is too small, it is likely to be damaged by peeling charge, and it is preferably 0.1 mm or more, more preferably 0.2 mm or more.
　本発明のガラス基板の剥離帯電をさらに抑えるためには、少なくとも一方の表面が微細凹凸面であることが望ましい。微細凹凸面の表面形状としては、表面粗さＲａが０．１～１０ｎｍとなるようにすればよい。ガラス基板表面を微細凹凸面にするための方法としては、研磨装置を用いた物理的研磨や、ガラス基板にエッチング液を塗布したり、エッチングガスを噴霧したりする化学エッチングによる方法を採用すれば良い。後者の化学エッチングを採用すると、ガラス基板にガラス粉などが付着しにくく、表面の清浄化が図れるため好ましい。本発明のガラス基板は、もともと剥離帯電を引き起こしにくいため、その表面に微細な凹凸を形成する場合でも、その加工時間を短縮し、生産性の向上を図ることが可能となる。 In order to further suppress peeling charge of the glass substrate of the present invention, it is desirable that at least one surface is a fine uneven surface. The surface roughness Ra may be 0.1 to 10 nm as the surface shape of the fine uneven surface. As a method for making the surface of the glass substrate a fine uneven surface, physical etching using a polishing apparatus or chemical etching in which an etching solution is applied to the glass substrate or an etching gas is sprayed may be adopted. good. It is preferable to use the latter chemical etching because glass powder and the like are less likely to adhere to the glass substrate and the surface can be cleaned. Since the glass substrate of the present invention is originally unlikely to cause peeling charge, even when fine irregularities are formed on the surface, the processing time can be shortened and productivity can be improved.
　本発明によれば、熱収縮率が低いため高精細のディスプレイ基板として好適であり、剥離帯電を引き起こしにくいガラス基板を安定して得ることが可能である。 According to the present invention, it is possible to stably obtain a glass substrate which is suitable as a high definition display substrate due to its low thermal shrinkage and which is less likely to cause peeling charge.
ガラス基板の熱収縮率を測定する方法を示す説明図である。It is explanatory drawing which shows the method to measure the thermal contraction rate of a glass substrate. ガラス基板の剥離帯電量の測定に用いる装置を示す説明図であり、（ａ）はガラス基板をテーブルから離間させた状態を示す説明図、（ｂ）はガラス基板をテーブルに載置した状態を示す説明図である。It is explanatory drawing which shows the apparatus used for the measurement of the peeling charge amount of a glass substrate, (a) is explanatory drawing which shows the state which made the glass substrate separate from the table, (b) shows the state which mounted the glass substrate on the table. FIG.
　本明細書において「～」を用いて示された数値範囲は、「～」の前後に記載の数値を最小値及び最大値としてそれぞれ含む範囲を意味する。 In the present specification, a numerical range indicated using “to” means a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.
　本発明のガラス基板は、質量百分率で、ＳｉＯ２　５０～７０％、Ａｌ２Ｏ３　１０～２５％、Ｂ２Ｏ３　０％以上３％未満、ＭｇＯ　０～１０％、ＣａＯ　０～１５％、ＳｒＯ　０～１０％、ＢａＯ　０～１５％、Ｎａ２Ｏ　０．００５～０．３％を含有する。上記のように各ガラス構成成分の含有量を規制した理由を以下に説明する。尚、以下の各成分の％表示は、特に断りのない限り、質量％を指す。 The glass substrate of the present invention is, by mass percentage, 50 to 70% SiO 2 , 10 to 25% Al 2 O 3 , 0 to 3% B 2 O 3 , 0 to 10% MgO, 0 to 15% CaO, It contains 0 to 10% of SrO, 0 to 15% of BaO, and 0.005 to 0.3% of Na 2 O. The reason for restricting the content of each glass component as described above will be described below. In addition,% indication of the following each component points to the mass% unless there is particular notice.
　ＳｉＯ２の含有量が少なくなると、耐薬品性、特に耐酸性が低下しやすくなると共に、歪点が低下しやすくなる。また密度が高くなり、ガラス基板の軽量化が図りにくくなる。ガラスの密度は、２．７０ｇ／ｃｍ３未満、さらには２．６５ｇ／ｃｍ３未満であることが好ましい。一方、ＳｉＯ２の含有量が多くなると、高温粘度が高くなって溶融性が低下しやすくなり、またエッチングする場合に時間がかかる。さらにＳｉＯ２系結晶、特にクリストバライトが析出して液相線粘度が低下、つまり耐失透性が低下しやすくなる。よってＳｉＯ２は、５０％以上、５５％以上、５８％以上、６０．５％以上、さらには６１％以上が好ましく、７０％以下、６５％以下、６４％以下、６３．５％以下、６３％以下、６２．５％以下、さらには６２％以下が好ましい。 When the content of SiO 2 decreases, the chemical resistance, in particular, the acid resistance tends to decrease, and the strain point tends to decrease. In addition, the density is increased, which makes it difficult to reduce the weight of the glass substrate. The density of the glass is preferably less than 2.70 g / cm 3 and even less than 2.65 g / cm 3 . On the other hand, when the content of SiO 2 increases, the high temperature viscosity becomes high and the meltability tends to be lowered, and it takes time in the case of etching. Furthermore, SiO 2 -based crystals, in particular cristobalite, precipitate and the liquidus viscosity decreases, that is, the devitrification resistance tends to decrease. Therefore, SiO 2 is 50% or more, 55% or more, 58% or more, 60.5% or more, more preferably 61% or more, 70% or less, 65% or less, 64% or less, 63.5% or less, 63 % Or less, 62.5% or less, and more preferably 62% or less.
　Ａｌ２Ｏ３の含有量が少なくなると、歪点が低下し、熱収縮率が大きくなると共に、ヤング率が低下してガラス基板がたわみやすくなる。一方、Ａｌ２Ｏ３の含有量が多くなると、耐ＢＨＦ（バッファードフッ酸）性が低下し、ガラス表面に白濁が生じやすくなると共に、耐クラック抵抗性が低下して破損しやすくなる。さらにガラス中にＳｉＯ２－Ａｌ２Ｏ３系結晶、特にムライトが析出して、液相線粘度が低下しやすくなる。よってＡｌ２Ｏ３は、１０％以上、１３％以上、１５％以上、１６％以上、１７％以上、１７．５％以上、さらには１８％以上が好ましく、２５％以下、２３％以下、２１％以下、２０％以下、１９％以下、１９．７％以下、さらには１９．５％以下が好ましい。 When the content of Al 2 O 3 is decreased, the strain point is lowered, the thermal contraction rate is increased, and the Young's modulus is decreased, and the glass substrate is easily bent. On the other hand, when the content of Al 2 O 3 is increased, the resistance to BHF (buffered hydrofluoric acid) is lowered and the glass surface is likely to be clouded, and the crack resistance is lowered to be easily broken. Furthermore, SiO 2 —Al 2 O 3 series crystals, particularly mullite, are precipitated in the glass, and the liquidus viscosity tends to be lowered. Therefore, Al 2 O 3 is 10% or more, 13% or more, 15% or more, 16% or more, 17% or more, 17.5% or more, preferably 18% or more, and 25% or less, 23% or less, 21 % Or less, 20% or less, 19% or less, 19.7% or less, and further preferably 19.5% or less.
　Ｂ２Ｏ３は、融剤として働き、粘性を低下して溶融性を改善する成分である。Ｂ２Ｏ３の含有量が多くなると、溶融ガラスが揮発してガラス成分が変動しやすい。またＢ２Ｏ３の含有量が多くなるほど、歪点が低下すると共に、耐熱性や耐酸性も低下しやすくなる。さらにヤング率が低下してガラス基板のたわみ量が大きくなりやすい。よってＢ２Ｏ３は、３％未満、２％以下、１．７％以下、１．５％以下、１．４％以下、１％以下、さらには実質的に含有しないことが好ましい。ただし溶融性を向上し、耐ＢＨＦ性や耐クラック性の低下を防ぐという観点から、Ｂ２Ｏ３は０．１％以上、０．２％以上、０．３％以上、０．４％以上、さらには０．５％以上含有させても良い。 B 2 O 3 is a component that acts as a flux and reduces the viscosity to improve the meltability. When the content of B 2 O 3 increases, the molten glass is volatilized and the glass component tends to fluctuate. Further, as the content of B 2 O 3 increases, the strain point is lowered, and the heat resistance and the acid resistance are also easily lowered. Furthermore, the Young's modulus is lowered, and the deflection of the glass substrate tends to be large. Therefore, it is preferable that B 2 O 3 is not contained substantially less than 3%, 2% or less, 1.7% or less, 1.5% or less, 1.4% or less, 1% or less. However, B 2 O 3 is 0.1% or more, 0.2% or more, 0.3% or more, 0.4% or more from the viewpoint of improving the meltability and preventing the decrease in BHF resistance and crack resistance. Furthermore, 0.5% or more may be contained.
　上記したようにガラスのβ－ＯＨ値は、ガラス溶融炉に投入されるガラスバッチに含まれる水分の影響を受けやすく、特にホウ素源となるガラス原料は吸湿性があり、また結晶水を含むものもあるため、ガラス中に水分を持ち込みやすい。そのためガラス中のＢ２Ｏ３の含有量を少なくするほど、ガラスのβ－ＯＨ値は低下しやすくなる。またβ－ＯＨ値が低下するほど、ガラスの歪点が高くなり、ガラス基板の熱収縮率の低下を図りやすくなる。以上の理由から、本発明においては、できるだけＢ２Ｏ３を少なくすることが好ましく、実質的にＢ２Ｏ３を含有しないことが望ましい。ここで実質的にＢ２Ｏ３を含有しないとは、意図的に原料としてＢ２Ｏ３を含有させないという意味であり、不純物からの混入を否定するものではない。具体的にはＢ２Ｏ３の含有量が０．１％以下であることを意味する。 As described above, the β-OH value of the glass is susceptible to the moisture contained in the glass batch charged into the glass melting furnace, and in particular, the glass material serving as the boron source is hygroscopic and contains crystal water. Because there is also, it is easy to bring moisture into the glass. Therefore, as the content of B 2 O 3 in the glass decreases, the β-OH value of the glass tends to decrease. Further, as the β-OH value decreases, the strain point of the glass becomes higher, and it becomes easier to reduce the heat shrinkage of the glass substrate. From the above reasons, in the present invention, it is preferable to reduce B 2 O 3 as much as possible, and it is desirable not to substantially contain B 2 O 3 . Here, the substantially free of B 2 O 3, a means that does not contain B 2 O 3 as intentionally raw material, does not exclude the contamination from impurities. Specifically, it means that the content of B 2 O 3 is 0.1% or less.
　ＭｇＯは、高温粘性を下げて溶融性を高める成分であり、アルカリ土類金属酸化物の中では、ヤング率を顕著に高める成分であるが、過剰に導入すると、ＳｉＯ２系結晶、特にクリストバライトが析出して液相線粘度が低下しやすくなる。さらにＭｇＯは、ＢＨＦと反応して生成物を形成しやすい成分である。ＭｇＯの含有量が少なくなると、上記効果を享受し難くなり、ＭｇＯが多くなると、耐失透性や歪点が低下しやすくなる。よってＭｇＯの含有量は、１０％以下、９％以下、８％以下、６％以下、５％以下、４％以下、３．５％以下、特に３％以下であることが好ましい。また１％以上、１．５％以上、特に２％以上であることが好ましい。 MgO is a component that lowers the viscosity at high temperature to enhance the meltability, and among alkaline earth metal oxides is a component that significantly increases the Young's modulus, but when introduced in excess, SiO 2 -based crystals, especially cristobalite It precipitates and the liquidus viscosity tends to decrease. Furthermore, MgO is a component that easily reacts with BHF to form a product. When the content of MgO is reduced, it is difficult to receive the above effect, and when the content of MgO is increased, the devitrification resistance and the strain point are easily reduced. Therefore, the content of MgO is preferably 10% or less, 9% or less, 8% or less, 6% or less, 5% or less, 4% or less, 3.5% or less, particularly 3% or less. Further, it is preferably 1% or more and 1.5% or more, particularly 2% or more.
　ＣａＯは、歪点を低下させずに、高温粘性を下げて溶融性を顕著に高める成分である。またアルカリ土類金属酸化物の中では、導入原料が比較的安価であるため、原料コストを低廉化する成分である。ＣａＯの含有量が少なくなると、上記効果を享受し難くなる。一方、ＣａＯの含有量が多くなりすぎると、ガラスが失透しやすくなると共に、熱膨張係数が高くなりやすい。よってＣａＯの含有量は、１５％以下、１２％以下、１１％以下、８％以下、特に６％以下であることが好ましい。また１％以上、２％以上、３％以上、４％以上、特に５％以上であることが好ましい。 CaO is a component that lowers the high temperature viscosity and significantly enhances the meltability without reducing the strain point. Further, among the alkaline earth metal oxides, since the introduced material is relatively inexpensive, it is a component that reduces the cost of the material. When the content of CaO decreases, it becomes difficult to receive the above effects. On the other hand, when the content of CaO is too large, the glass is likely to be devitrified and the thermal expansion coefficient tends to be high. Therefore, the content of CaO is preferably 15% or less, 12% or less, 11% or less, 8% or less, particularly 6% or less. Further, it is preferably 1% or more, 2% or more, 3% or more, 4% or more, particularly 5% or more.
　ＳｒＯは、ガラスの分相を抑制し、耐失透性を高める成分である。さらに歪点を低下させずに高温粘性を下げて溶融性を高めると共に、液相温度の上昇を抑制する成分である。ＳｒＯの含有量が少なくなると、上記効果を享受し難くなる。一方、ＳｒＯの含有量が多くなると、ストロンチウムシリケート系の失透結晶が析出しやすくなって耐失透性が低下しやすくなる。よってＳｒＯの含有量は、１０％以下、７％以下、５％以下、４％以下、特に３％以下であることが好ましい。また０．１％以上、０．２％以上、０．３％以上、０．５％以上、１．０％以上、特に１．５％以上であることが好ましい。 SrO is a component that suppresses the phase separation of glass and enhances the devitrification resistance. Furthermore, it is a component which suppresses the rise of liquidus temperature while lowering the high temperature viscosity and reducing the melting point without lowering the strain point. When the content of SrO decreases, it is difficult to receive the above effects. On the other hand, when the content of SrO is increased, devitrification crystals of the strontium silicate system are easily precipitated, and the devitrification resistance is easily reduced. Therefore, the content of SrO is preferably 10% or less, 7% or less, 5% or less, 4% or less, particularly 3% or less. Further, 0.1% or more, 0.2% or more, 0.3% or more, 0.5% or more, 1.0% or more, particularly preferably 1.5% or more.
　ＢａＯは、耐失透性を顕著に高める成分である。ＢａＯの含有量が少なくなると、上記効果を享受し難くなる。一方、ＢａＯの含有量が多くなると、密度が高くなりすぎると共に、溶融性が低下しやすくなる。またＢａＯを含む失透結晶が析出しやすくなって液相温度が上昇しやすくなる。よってＢａＯの含有量は、１５％以下、１４％以下、１３％以下、１２％以下、１１％以下、１０．５％以下、１０％以下、９．５％以下、特に９％以下であることが好ましい。また１％以上、３％以上、４％以上、５％以上、６％以上、特に７％以上であることが好ましい。 BaO is a component that significantly enhances the devitrification resistance. When the content of BaO decreases, it becomes difficult to receive the above effects. On the other hand, when the content of BaO increases, the density becomes too high and the meltability tends to be reduced. In addition, devitrified crystals containing BaO are easily precipitated, and the liquidus temperature tends to rise. Therefore, the content of BaO is 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10.5% or less, 10% or less, 9.5% or less, particularly 9% or less Is preferred. Further, it is preferably 1% or more, 3% or more, 4% or more, 5% or more, 6% or more, particularly 7% or more.
　Ｎａ２Ｏは、ガラスの比抵抗を低下する成分である。Ｎａ２Ｏの含有量が少なくなると、上記効果を享受し難くなる。一方、Ｎａ２Ｏの含有量が多くなると、熱処理時にアルカリイオンが成膜された半導体物質中に拡散し、膜の特性の劣化を招く。よってＮａ２Ｏは、０．００５％以上、０．００８％以上、０．０１％以上、０．０２％以上、０．０２５％以上、０．０３％以上、さらには０．０５％以上が好ましく、０．３％以下、さらには０．２％以下が好ましい。 Na 2 O is a component that reduces the specific resistance of glass. When the content of Na 2 O decreases, it is difficult to receive the above effects. On the other hand, when the content of Na 2 O is increased, alkali ions are diffused into the formed semiconductor substance at the time of heat treatment, resulting in deterioration of film properties. Therefore, Na 2 O is 0.005% or more, 0.008% or more, 0.01% or more, 0.02% or more, 0.025% or more, 0.03% or more, or 0.05% or more. Preferably, it is 0.3% or less, more preferably 0.2% or less.
　Ｎａ２Ｏ以外のアルカリ金属酸化物としてＫ２Ｏを添加してもよい。Ｋ２Ｏもガラスの比抵抗を低下する成分である。Ｋ２Ｏの含有量が少なくなると、上記効果を享受し難くなる。一方、Ｋ２Ｏの含有量が多くなると、熱処理時にアルカリイオンが成膜された半導体物質中に拡散し、膜の特性の劣化を招く。よってＫ２Ｏは、０．００１％以上、０．００２％以上、０．００５％以上、０．０１％以上、０．０２％以上、０．０２５％以上、０．０３％以上、さらには０．０５％以上が好ましく、０．３％以下、さらには０．２％以下が好ましい。Ｋ２Ｏは、Ｎａ２Ｏより多く含有させることが可能である。 K 2 O may be added as an alkali metal oxide other than Na 2 O. K 2 O is also a component that reduces the specific resistance of glass. As the content of K 2 O decreases, it becomes difficult to receive the above effects. On the other hand, when the content of K 2 O is increased, alkali ions are diffused into the formed semiconductor substance during heat treatment, resulting in deterioration of film properties. Therefore, K 2 O is 0.001% or more, 0.002% or more, 0.005% or more, 0.01% or more, 0.02% or more, 0.025% or more, 0.035% or more, or more. 0.05% or more is preferable, 0.3% or less, further 0.2% or less is preferable. K 2 O can be contained more than Na 2 O.
　さらに、Ｎａ２Ｏ、Ｋ２Ｏ以外のアルカリ金属酸化物であるＬｉ２Ｏも、適宜添加することが可能である。ただしアルカリ金属酸化物の含有量が多くなると、熱処理時にアルカリイオンが成膜された半導体物質中に拡散し、膜の特性の劣化を招くため、アルカリ金属酸化物の総量（Ｎａ２Ｏ、Ｌｉ２Ｏ及びＫ２Ｏの合量）は０．４％以下とすることが好ましい。 Furthermore, it is possible to appropriately add Li 2 O which is an alkali metal oxide other than Na 2 O and K 2 O. However, when the content of the alkali metal oxide increases, alkali ions diffuse into the formed semiconductor material during heat treatment, which causes deterioration of the film characteristics. Therefore, the total amount of alkali metal oxides (Na 2 O, Li 2 The total amount of O and K 2 O) is preferably 0.4% or less.
　本発明においては、ガラス基板に上記成分に加えて次の成分を含有させることが可能である。 In the present invention, it is possible to add the following components to the glass substrate in addition to the above components.
　本発明のガラス基板はＦｅ２Ｏ３を０．００５～０．１％含有することが好ましい。Ｆｅ２Ｏ３は、Ｎａ２Ｏと同様、ガラスの比抵抗を低下させる作用を有する成分であり、Ｆｅ２Ｏ３を一定量以上含有させることによって、ガラス基板の帯電を抑制する効果がより高まる。Ｆｅ２Ｏ３は、０．００５％以上、０．００８％以上、特に０．０１％以上含有することが好ましい。ただしＦｅ２Ｏ３を０．１％超含有すると、ガラスの透過率が低下するためディスプレイ基板として好ましくなくなるおそれがあるため、Ｆｅ２Ｏ３は０．１％以下が好ましい。 The glass substrate of the present invention preferably contains 0.005 to 0.1% of Fe 2 O 3 . Similar to Na 2 O, Fe 2 O 3 is a component having the function of reducing the specific resistance of glass, and the effect of suppressing charging of the glass substrate is further enhanced by containing Fe 2 O 3 in a certain amount or more. . The Fe 2 O 3 content is preferably 0.005% or more, 0.008% or more, and particularly preferably 0.01% or more. However, if the content of Fe 2 O 3 is more than 0.1%, the transmittance of the glass is lowered, and there is a possibility that the glass is not preferable as a display substrate. Therefore, the content of Fe 2 O 3 is preferably 0.1% or less.
　本発明のガラス基板はＳｎＯ２を０．００１～０．５％含有することが好ましい。ＳｎＯ２は、高温域で良好な清澄作用を有し、歪点を高めると共に高温粘性を低下させる成分である。またモリブデン電極を使用した電気溶融炉の場合、電極を浸食しないという利点がある。一方、ＳｎＯ２の含有量が多くなると、ＳｎＯ２の失透結晶が析出しやすくなり、またＺｒＯ２の失透結晶の析出を促進しやすくなる。よってＳｎＯ２の含有量は、０．００１～０．５％、０．００１～０．４５％、０．００１～０．４％、０．０１～０．３５％、０．１～０．３％、特に０．１５～０．３％であることが好ましい。 The glass substrate of the present invention preferably contains 0.001 to 0.5% of SnO 2 . SnO 2 is a component that has a good fining action in the high temperature range, and increases the strain point and reduces the high temperature viscosity. In the case of an electric melting furnace using a molybdenum electrode, there is an advantage that the electrode is not corroded. On the other hand, when the content of SnO 2 increases, devitrified crystals of SnO 2 easily precipitate and it becomes easy to promote the precipitation of devitrified crystals of ZrO 2 . Therefore, the content of SnO 2 is 0.001 to 0.5%, 0.001 to 0.45%, 0.001 to 0.4%, 0.01 to 0.35%, 0.1 to 0. It is preferably 3%, particularly 0.15 to 0.3%.
　さらに、本発明のガラス基板が含有してもよいその他の成分について説明する。 Further, other components which may be contained in the glass substrate of the present invention will be described.
　ＺｎＯは、溶融性を高める成分である。しかしＺｎＯの含有量が多くなると、ガラスが失透しやすくなると共に歪点が低下しやすくなる。ＺｎＯの含有量は０～５％、０～４％、０～３％、特に０～２％であることが好ましい。 ZnO is a component that enhances the meltability. However, when the content of ZnO is increased, the glass is likely to be devitrified and the strain point is easily reduced. The content of ZnO is preferably 0 to 5%, 0 to 4%, 0 to 3%, particularly 0 to 2%.
　ＺｒＯ２は、化学的耐久性を高める成分であるが、ＺｒＯ２の含有量が多くなると、ＺｒＳｉＯ４の失透ブツが発生しやすくなる。ＺｒＯ２の含有量は、０～５％、０～４％、０～３％、特に０．０１～２％であることが好ましい。 ZrO 2 is a component that enhances chemical durability, but when the content of ZrO 2 is large, devitrification of ZrSiO 4 tends to occur. The content of ZrO 2 is preferably 0 to 5%, 0 to 4%, 0 to 3%, particularly 0.01 to 2%.
　ＴｉＯ２は、高温粘性を下げて溶融性を高めると共に、ソラリゼーションによる着色を抑制する成分であるが、ＴｉＯ２の含有量が多くなると、ガラスが着色して透過率が低下しやすくなる。ＴｉＯ２の含有量は、０～５％、０～４％、０～３％、０～２％、特に０～０．１％であることが好ましい。 TiO 2 is a component that lowers high-temperature viscosity to enhance meltability and suppresses coloring due to solarization, but if the content of TiO 2 is large, the glass becomes colored and the transmittance tends to be reduced. The content of TiO 2 is preferably 0 to 5%, 0 to 4%, 0 to 3%, 0 to 2%, particularly 0 to 0.1%.
　Ｐ２Ｏ５は、歪点を高めると共に、アノーサイト等のアルカリ土類アルミノシリケート系の失透結晶の析出を抑制する成分である。ただしＰ２Ｏ５を多量に含有させると、ガラスが分相しやすくなる。Ｐ２Ｏ５の含有量は、好ましくは、０～０．１５％未満、０～１％、０～０．１％であり、特にガラスのリサイクルを容易にするという点から実質的に含有しないこと、具体的には０．０１％未満であることが望ましい。 P 2 O 5 is a component that enhances the strain point and suppresses the precipitation of devitrified crystals of an alkaline earth aluminosilicate system such as anorthite. However, when a large amount of P 2 O 5 is contained, the phase separation of the glass is facilitated. The content of P 2 O 5 is preferably 0 to less than 0.15%, 0 to 1%, or 0 to 0.1%, and in particular, does not substantially contain it in terms of facilitating glass recycling. Specifically, it is desirable to be less than 0.01%.
　Ｃｌ、Ｆ、ＳＯ３、Ｃ、ＣｅＯ２或いはＡｌ、Ｓｉ等の金属粉末は合量で３％まで含有させることができる。Ａｓ２Ｏ３やＳｂ２Ｏ３は、清澄剤として有用であるが、環境や電極の浸食防止の観点から実質的に含有しないことが望ましい。ここで実質的に含有しないとは、Ａｓ２Ｏ３とＳｂ２Ｏ３の合量が０．１％以下であることを意味する。 Metal powders such as Cl, F, SO 3 , C, CeO 2 or Al, Si can be contained up to 3% in total. As 2 O 3 and Sb 2 O 3 are useful as a fining agent, but it is desirable not to contain substantially from the viewpoint of preventing the environment and erosion of the electrode. Here, “not substantially contained” means that the total amount of As 2 O 3 and Sb 2 O 3 is 0.1% or less.
　本発明のガラス基板は、β－ＯＨ値が０．１８／ｍｍ未満である。ガラスのβ－ＯＨ値が低下するほど、ガラスの歪点が高くなり、熱収縮率が低くなるため、β－ＯＨ値は、０．１５／ｍｍ未満、０．１２／ｍｍ以下、０．１／ｍｍ以下、０．０７／ｍｍ以下、特に０．０５／ｍｍ以下であることが好ましい。ただしガラス基板の帯電を抑制するという観点から、β－ＯＨ値は０．０１／ｍｍ以上、０．０２／ｍｍ以上、特に０．０３／ｍｍ以上であることが好ましい。 The glass substrate of the present invention has a β-OH value of less than 0.18 / mm. The lower the β-OH value of the glass, the higher the strain point of the glass and the lower the thermal contraction rate. Therefore, the β-OH value is less than 0.15 / mm, 0.12 / mm or less, 0.1 / Mm or less, 0.07 / mm or less, particularly preferably 0.05 / mm or less. However, from the viewpoint of suppressing charging of the glass substrate, the β-OH value is preferably 0.01 / mm or more, 0.02 / mm or more, and particularly preferably 0.03 / mm or more.
　本発明のガラス基板は、歪点が７３５℃以上である。ガラス基板の熱収縮率を低下させるためには、歪点をできるだけ高くすることが望ましく、７４０℃以上、７４５℃以上、さらには７５０℃以上であることが好ましい。ただし歪点を高めようとするほど、ガラス溶融時や成形時の温度が高くなり、ガラス基板の製造コストが高騰するため、歪点は８００℃以下とすることが好ましい。 The strain point of the glass substrate of the present invention is 735 ° C. or more. In order to reduce the thermal contraction rate of the glass substrate, it is desirable to make the strain point as high as possible, preferably 740 ° C. or more, 745 ° C. or more, and more preferably 750 ° C. or more. However, as the strain point is to be increased, the temperature at the time of melting or molding of the glass becomes higher and the manufacturing cost of the glass substrate rises, so the strain point is preferably 800 ° C. or less.
　本発明のガラス基板は、歪点と同様の理由で、徐冷点が、７８０℃以上、７９０℃以上、８００℃以上、８１０℃以上、特に８２０℃以上であることが好ましい。ただし徐冷点を高めようとするほど、ガラス溶融時や成形時の温度が高くなり、ガラス基板の製造コストが高騰するため、徐冷点は８５０℃以下、さらに８４０℃以下とすることが好ましい。 The glass substrate of the present invention preferably has an annealing point of 780 ° C. or more, 790 ° C. or more, 800 ° C. or more, 810 ° C. or more, particularly 820 ° C. or more, for the same reason as the strain point. However, as the annealing temperature is increased, the temperature during melting and molding of the glass increases and the manufacturing cost of the glass substrate rises, so the annealing temperature is preferably 850 ° C. or less, more preferably 840 ° C. or less .
　本発明のガラス基板は、ヤング率が８０ＧＰａ以上であることが好ましい。ヤング率が高いほど、ガラス基板のたわみが小さくなり、搬送時や梱包時のハンドリングが容易となる。ヤング率は、８１ＧＰａ以上、８２ＧＰａ以上、８３ＧＰａ以上、８４ＧＰａ以上、さらには８５ＧＰａ以上が好ましい。 The glass substrate of the present invention preferably has a Young's modulus of 80 GPa or more. The higher the Young's modulus, the smaller the deflection of the glass substrate, and the easier handling during transportation or packing. The Young's modulus is preferably 81 GPa or more, 82 GPa or more, 83 GPa or more, 84 GPa or more, and more preferably 85 GPa or more.
　本発明のガラス基板は、１０４．５ｄＰａ・ｓに相当する温度が、１３３０℃以下、１３２０℃以下、特に１３１０℃以下であることが好ましい。１０４．５ｄＰａ・ｓに相当する温度が高くなると、成形時の温度が高くなりすぎて、製造歩留まりが低下しやすくなる。 The glass substrate of the present invention preferably has a temperature corresponding to 10 4.5 dPa · s of 1330 ° C. or less, 1320 ° C. or less, and particularly 1310 ° C. or less. When the temperature corresponding to 10 4.5 dPa · s becomes high, the temperature at the time of molding becomes too high, and the production yield tends to be lowered.
　本発明のガラス基板は、１０２．５ｄＰａ・ｓに相当する温度が１６７０℃以下、１６６０℃以下、特に１６５０℃以下であることが好ましい。１０２．５ｄＰａ・ｓに相当する温度が高くなると、ガラスが溶融し難くなり、泡等の欠陥が増加したり、製造歩留まりが低下しやすくなる。 The glass substrate of the present invention preferably has a temperature corresponding to 10 2.5 dPa · s of 1670 ° C. or less, 1660 ° C. or less, particularly 1650 ° C. or less. When the temperature corresponding to 10 2.5 dPa · s becomes high, the glass becomes difficult to melt, defects such as bubbles increase, and the production yield tends to decrease.
　本発明のガラス基板は、液相温度が１２５０℃未満、１２４０℃未満、１２３０℃未満、特に１２２０℃未満であることが好ましい。このようにすれば、ガラス製造時に失透結晶が発生し難くなるため、オーバーフローダウンドロー法で板状に成形しやすくなる。これにより、ガラス基板の表面品位を向上すると共に、製造歩留まりの低下を抑えることができる。ガラス基板の大型化やディスプレイの高精細化の観点から、ガラスの耐失透性を高め、表面欠陥となり得る失透物を極力抑える意義は非常に大きい。 The glass substrate of the present invention preferably has a liquidus temperature of less than 1250 ° C., less than 1240 ° C., less than 1230 ° C., and particularly less than 1220 ° C. In this way, devitrified crystals are less likely to occur during glass production, and therefore, it becomes easy to form into a plate by the overflow down draw method. Thereby, the surface quality of the glass substrate can be improved, and a decrease in manufacturing yield can be suppressed. From the viewpoint of increasing the size of the glass substrate and increasing the definition of the display, it is extremely important to enhance the devitrification resistance of the glass and to minimize devitrified substances that may become surface defects.
　本発明のガラス基板は、液相温度における粘度が１０４．９ｄＰａ・ｓ以上、１０５．０ｄＰａ・ｓ１０５．１ｄＰａ・ｓ以上、１０５．２ｄＰａ・ｓ以上、特に１０５．３ｄＰａ・ｓ以上であることが好ましい。このようにすれば、ガラス成形時に失透が生じ難くなるため、オーバーフローダウンドロー法で板状に成形しやすくなり、ガラス基板の表面品位を高めることができる。尚、液相温度における粘度は、成形性の指標であり、液相温度における粘度が高い程、成形性が向上する。 The glass substrate of the present invention has a viscosity at a liquidus temperature of 10 4.9 dPa · s or more, 10 5.0 dPa · s 10 5.1 dPa · s or more, 10 5.2 dPa · s or more, in particular 10 5. It is preferably 3 dPa · s or more. In this way, devitrification is less likely to occur at the time of glass forming, so it becomes easy to form in a plate shape by the overflow down draw method, and the surface quality of the glass substrate can be improved. The viscosity at the liquidus temperature is an index of formability, and the formability improves as the viscosity at the liquidus temperature is higher.
（実施例１）
　表１、２は、本発明の実施例ガラス（試料Ｎｏ.１～９）と従来ガラス（試料Ｎｏ．１０）を示すものである。尚、表中のＮａ２Ｏ、Ｋ２Ｏ、Ｆｅ２Ｏ３、ＺｒＯ２以外の成分の含有量は、小数第２位を四捨五入したものである。 Example 1
Tables 1 and 2 show example glasses of the present invention (samples No. 1 to 9) and conventional glasses (sample No. 10). The contents of the components other than Na 2 O, K 2 O, Fe 2 O 3 , and ZrO 2 in the table are rounded off to one decimal place.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１、２のガラス試料は、次にようにして作製した。まず表中の組成となるようにガラス原料を調合したガラスバッチを白金坩堝に入れた後、１６００～１６５０℃で２４時間溶融した。ガラスバッチの溶融にあたっては、白金スターラーを用いて撹拌し、均質化を行った。次いで、溶融ガラスをカーボン板上に流し出して板状に成形した後、徐冷点付近の温度で３０分間徐冷した。こうして得られた各試料について、歪点、徐冷点、密度、ヤング率、１０４．５ｄＰａ・ｓに相当する温度、１０２．５ｄＰａ・ｓに相当する温度、液相温度ＴＬ、液相温度における粘度ηＴＬ（ｄＰａ・ｓ）についてＬｏｇ１０ηＴＬを測定した。 The glass samples in Tables 1 and 2 were prepared as follows. First, a glass batch prepared by preparing glass raw materials to have the composition shown in the table was put into a platinum crucible and melted at 1600 to 1650 ° C. for 24 hours. In melting the glass batch, it was stirred using a platinum stirrer and homogenized. Next, the molten glass was poured out on a carbon plate and formed into a plate, and then annealed for 30 minutes at a temperature near the annealing point. For each sample thus obtained, strain point, annealing point, density, Young's modulus, temperature corresponding to 10 4.5 dPa · s, temperature corresponding to 10 2.5 dPa · s, liquidus temperature TL, liquid Log 10 η TL was measured for viscosity TL TL (dPa · s) at the phase temperature.
　尚、表１、２中の歪点、徐冷点は、ＡＳＴＭ　Ｃ３３６の方法で測定した。 The strain points and annealing points in Tables 1 and 2 were measured by the method of ASTM C336.
　密度は、ＡＳＴＭ　Ｃ６９３によるアルキメデス法で測定した。 The density was measured by Archimedes method according to ASTM C693.
　ヤング率は、ＪＩＳＲ１６０２による曲げ共振法により測定した。 Young's modulus was measured by a bending resonance method according to JIS R1602.
　１０４．５ｄＰａ・ｓ及び１０２．５ｄＰａ・ｓに相当する温度は、白金球引き上げ法で測定した。 The temperatures corresponding to 10 4.5 dPa · s and 10 2.5 dPa · s were measured by a platinum ball pulling method.
　液相温度ＴＬは、標準篩３０メッシュ（５００μｍ）を通過し、５０メッシュ（３００μｍ）に残るガラス粉末を白金ボートに投入し、１１００℃から１３５０℃に設定された温度勾配炉中に２４時間保持した後、白金ボートを取り出し、ガラス中に失透（結晶異物）が認められた温度を測定した。 The liquidus temperature TL passes through a standard sieve of 30 mesh (500 μm), and the glass powder remaining on 50 mesh (300 μm) is charged into a platinum boat and held for 24 hours in a temperature gradient furnace set at 1100 ° C. to 1350 ° C. After that, the platinum boat was taken out, and the temperature at which devitrification (crystal foreign matter) was observed in the glass was measured.
　液相温度における粘度Ｌｏｇ１０ηＴＬは、白金球引き上げ法で液相温度におけるガラスの粘度ηＴＬを測定し、Ｌｏｇ１０ηＴＬを算出した。 The viscosity Log 10 ηTL at the liquidus temperature was measured by measuring the viscosity ηTL of the glass at the liquidus temperature by a platinum ball pulling method, and the Log 10 ηTL was calculated.
　β－ＯＨ値は、ＦＴ－ＩＲを用いてガラスの透過率を測定し、下記の式を用いて求めた。
　　β－ＯＨ値　＝　（１／Ｘ）ｌｏｇ（Ｔ１／Ｔ２）
　Ｘ：ガラス肉厚（ｍｍ）
　Ｔ１：参照波長３８４６ｃｍ－１における透過率（％）
　Ｔ２：水酸基吸収波長３６００ｃｍ－１付近における最小透過率（％） The β-OH value was obtained by measuring the transmittance of glass using FT-IR and using the following equation.
β-OH value = (1 / X) log (T1 / T2)
X: Glass thickness (mm)
T1: transmittance at a reference wavelength 3846 cm -1 (%)
T2: Minimum transmittance in the vicinity of the hydroxyl group absorption wavelength 3600 cm -1 (%)
　表１および２から明らかなように、Ｎｏ.１～９の各試料は、歪点が７３５℃以上、徐冷点が７８５℃以上であるため、熱収縮率を２０ｐｐｍ以下にしやすいガラスである。またヤング率が８０．４ＧＰａ以上であるため、たわみにくく、液相温度ＴＬが１２４６℃以下、液相温度における粘度ηＴＬが１０４．９ｄＰａ・ｓ以上であるため、成形時に失透が生じ難い。特にＮｏ．１、２、７～９の各試料は、液相温度における粘度ηＴＬが１０５．２ｄＰａ・ｓ以上であるため、オーバーフローダウンドロー法に適したものであった。 As is apparent from Tables 1 and 2, each of the samples No. 1 to No. 9 is a glass which tends to have a thermal shrinkage of 20 ppm or less because the strain point is 735 ° C. or more and the slow cooling point is 785 ° C. or more. Further, since the Young's modulus is 80.4 GPa or more, it is difficult to bend, and since the liquid phase temperature TL is 1246 ° C. or less and the viscosity TLTL at the liquid phase temperature is 10 4.9 dPa · s or more, devitrification hardly occurs during molding. . In particular, no. Each of the samples 1, 2 and 7 to 9 was suitable for the overflow down draw method because the viscosity η TL at the liquidus temperature was 10 5.2 dPa · s or more.
（実施例２）
　表２の試料Ｎｏ．８及び１０のガラスとなるようにガラスバッチを調製した。次いで、このガラスバッチを電気溶融炉に投入し、１６００～１６５０℃で溶融した後、清澄槽、均質化槽内で溶融ガラスを清澄均質化した後、ポット内で成形に適した粘度に調整した。次いで溶融ガラスをオーバーフローダウンドロー装置により板状に成形した後、長さ５ｍの徐冷炉において、徐冷点から（徐冷点－１００℃）の温度範囲での平均冷却速度を３８５℃／分に設定して徐冷した。その後、板状ガラスを切断し、端面加工することにより、１５００×１８５０×０．７ｍｍの寸法を有するガラス基板を作製した。 (Example 2)
Sample No. in Table 2 Glass batches were prepared to be 8 and 10 glasses. Next, the glass batch was put into an electric melting furnace, melted at 1600 to 1650 ° C., and then the molten glass was clarified and homogenized in a clarification tank and a homogenization tank, and then adjusted to a viscosity suitable for molding in a pot. . Next, the molten glass is formed into a plate shape by an overflow downdraw apparatus, and the average cooling rate in the temperature range from the annealing point to (annealing point -100 ° C) is set to 385 ° C / min in a 5-m long annealing furnace. Then it was slowly cooled. Thereafter, the plate-like glass was cut and edge-processed to prepare a glass substrate having dimensions of 1500 × 1850 × 0.7 mm.
　こうして得られた各ガラス基板のβ－ＯＨ値及び熱収縮率を測定したところ、試料Ｎｏ．８のガラス基板のβ－ＯＨ値は０．１／ｍｍ、熱収縮率は１０ｐｐｍであった。一方、試料Ｎｏ．１０のガラス基板のβ－ＯＨ値は０．３／ｍｍ、熱収縮率は２５ｐｐｍであった。 The β-OH value and the thermal contraction rate of each glass substrate thus obtained were measured. The β-OH value of the glass substrate of No. 8 was 0.1 / mm, and the thermal shrinkage was 10 ppm. On the other hand, for sample no. The β-OH value of the 10 glass substrates was 0.3 / mm, and the thermal shrinkage was 25 ppm.
　ガラス基板の熱収縮率は、次の方法で測定した。まず図１（ａ）に示すように、ガラス基板の試料として１６０ｍｍ×３０ｍｍの短冊状試料Ｇを準備した。この短冊状試料Ｇの長辺方向の両端部のそれぞれに、＃１０００の耐水研磨紙を用いて、端縁から２０～４０ｍｍ離れた位置でマーキングＭを形成した。その後、図１（ｂ）に示すように、マーキングＭを形成した短冊状試料ＧをマーキングＭと直交方向に沿って２つに折り割って、試料片Ｇａ、Ｇｂを作製した。そして、一方の試料片Ｇｂのみを、常温（２５℃）から５００℃まで５℃／分で昇温させ、５００℃で１時間保持した後に、５℃／分で常温まで降温させる熱処理を行った。上記熱処理後、図１（ｃ）に示すように、熱処理を行っていない試料片Ｇａと、熱処理を行った試料片Ｇｂを並列に配列した状態で、２つの試料片Ｇａ、ＧｂのマーキングＭの位置すれ量（△Ｌ１、△Ｌ２）をレーザー顕微鏡によって読み取り、下記の式により熱収縮率を算出した。尚、式中のｌ０は、初期のマーキングＭ間の距離である。
　熱収縮率　＝　[｛△Ｌｌ（μｍ）+△Ｌ２（μｍ）｝×１０３]／ｌ０（ｍｍ）（ｐｐｍ） The thermal contraction rate of the glass substrate was measured by the following method. First, as shown in FIG. 1A, a strip-shaped sample G of 160 mm × 30 mm was prepared as a sample of a glass substrate. A marking M was formed on each of both ends in the long side direction of the strip-like sample G using a water-resistant abrasive paper of # 1000 at a distance of 20 to 40 mm from the edge. Thereafter, as shown in FIG. 1B, the strip-like sample G on which the marking M was formed was broken into two along the direction orthogonal to the marking M to produce sample pieces Ga and Gb. Then, only one of the sample pieces Gb was heated from normal temperature (25 ° C.) to 500 ° C. at 5 ° C./min, held at 500 ° C. for 1 hour, and subjected to heat treatment to cool to normal temperature at 5 ° C./min. . After the heat treatment, as shown in FIG. 1C, in a state in which the sample piece Ga not subjected to the heat treatment and the sample piece Gb subjected to the heat treatment are arranged in parallel, the marking M of the two sample pieces Ga and Gb The amount of positional deviation (.DELTA.L1, .DELTA.L2) was read by a laser microscope, and the heat shrinkage was calculated by the following equation. In the equation, 10 is the distance between the initial markings M.
Thermal contraction rate = [{ΔLl (μm) + ΔL2 (μm)} × 10 3 ] / l 0 (mm) (ppm)
　次に上記の試料Ｎｏ．８、１０の各ガラス基板につき、図２に示す装置を使用して剥離帯電の評価を行った。 Next, the sample No. For each of the 8 and 10 glass substrates, evaluation of peeling charge was performed using an apparatus shown in FIG.
　図２（ａ）に示すようにガラス基板Ｇの支持台１は、ガラス基板Ｇの四隅を支持するテフロン（登録商標）製のパッド２を備えている。支持台１には、昇降可能な金属アルミニウム製のテーブル３が設けられており、図２（ｂ）に示すようにテーブル３を上下させることによって、ガラス基板Ｇとテーブル３を接触させた後、ガラス基板Ｇを剥離させることにより、ガラス基板Ｇを帯電させることができる。尚、テーブル３は、アースされている。またテーブル３には単数または複数の孔（図示省略）が形成されており、この孔がダイヤフロム型の真空ポンプ（図示省略）に接続されている。真空ポンプを駆動させると、テーブル３の孔から空気が吸引され、これによってガラス基板Ｇをテーブル３に真空吸着させることができる。またガラス基板Ｇの上方１０ｍｍの位置には表面電位計４が設置され、これによってガラス基板Ｇの中央部に発生する帯電量を連続測定する。またガラス基板Ｇの上方にはイオナイザ付きエアーガン５が設置されており、これによってガラス基板Ｇの帯電を徐電することができる。 As shown in FIG. 2A, the support base 1 of the glass substrate G is provided with pads 2 made of Teflon (registered trademark) for supporting the four corners of the glass substrate G. The support base 1 is provided with a table 3 made of metal aluminum which can be moved up and down, and after bringing the table 3 into contact with the glass substrate G by moving the table 3 up and down as shown in FIG. By peeling the glass substrate G, the glass substrate G can be charged. The table 3 is grounded. Further, one or more holes (not shown) are formed in the table 3, and the holes are connected to a diamond-shaped vacuum pump (not shown). When the vacuum pump is driven, air is sucked from the holes of the table 3, whereby the glass substrate G can be vacuum adsorbed to the table 3. Further, a surface voltmeter 4 is installed at a position 10 mm above the glass substrate G, by which the amount of charge generated at the central portion of the glass substrate G is continuously measured. In addition, an air gun 5 with an ionizer is installed above the glass substrate G, whereby the charging of the glass substrate G can be eliminated.
　この装置を用いて次の工程で、ガラス基板の剥離帯電を測定した。尚、実験は温度２５℃、湿度４０％のクリーンブース内で行った。帯電量は、雰囲気、特に大気中の湿度に影響を受けて大きく変化するため特に湿度の調整には配慮が必要である。 The peeling charge of the glass substrate was measured in the next step using this apparatus. The experiment was conducted in a clean booth at a temperature of 25 ° C. and a humidity of 40%. Since the amount of charge changes greatly under the influence of the atmosphere, particularly the humidity in the atmosphere, it is particularly necessary to adjust the humidity.
　（１）ガラス基板Ｇを支持台１の支持パッド２上に載置する。
　（２）イオナイザ付きエアーガン５によりガラス基板Ｇを徐電する。
　（３）テーブル３を上昇させてガラス基板Ｇに接触させると共に、真空吸着させてテーブル３とガラス基板Ｇを２０秒間密着させる。
　（４）テーブル３を下降させることでガラス基板Ｇをテーブル３から剥離し、ガラス基板Ｇの中央部に発生する帯電量を表面電位計４で連続的に測定する。
　（５）上記（３）と（４）の工程を繰り返すことにより、計５回の剥離評価を連続して行う。
　各測定における最大帯電量を求め、これらを積算して剥離帯電量とする。 (1) The glass substrate G is placed on the support pad 2 of the support 1.
(2) The glass substrate G is discharged by an air gun 5 with an ionizer.
(3) The table 3 is raised and brought into contact with the glass substrate G, and vacuum suction is carried out to bring the table 3 and the glass substrate G into close contact for 20 seconds.
(4) The table 3 is lowered to separate the glass substrate G from the table 3, and the amount of charge generated at the central portion of the glass substrate G is continuously measured by the surface voltmeter 4.
(5) A total of five peel evaluations are continuously performed by repeating the steps (3) and (4).
The maximum charge amount in each measurement is determined, and these are integrated to obtain a peeling charge amount.
　その結果、試料Ｎｏ．８のガラス基板の剥離帯電量が１０００Ｖであったのに対し、試料Ｎｏ．１０の剥離帯電量は２０００Ｖと大きかった。また試料Ｎｏ．８のガラス基板の一方の面にエッチングガスを噴霧し、表面粗さＲａを１ｎｍにした後、剥離帯電量を測定したところ、８００Ｖであった。 As a result, sample no. While the peeling charge amount of the glass substrate of No. 8 was 1000 V, Sample No. The peeling charge amount of 10 was as large as 2000V. Moreover, sample No. After the etching gas was sprayed onto one surface of the glass substrate No. 8 to make the surface roughness Ra 1 nm, the peeling charge amount was measured, and it was 800V.
Ｇ　　　ガラス試料（ガラス基板）
Ｍ　　　マーキング
１　　　支持台
２　　　パッド
３　　　テーブル
４　　　表面電位体
５　　　イオナイザ付きエアーガン G glass sample (glass substrate)
M Marking 1 Support base 2 Pad 3 Table 4 Surface potential body 5 Air gun with ionizer

Claims (14)

  1. 質量百分率で、ＳｉＯ２　５０～７０％、Ａｌ２Ｏ３　１０～２５％、Ｂ２Ｏ３　０％以上３％未満、ＭｇＯ　０～１０％、ＣａＯ　０～１５％、ＳｒＯ　０～１０％、ＢａＯ　０～１５％、Ｎａ２Ｏ　０．００５～０．３％を含有し、β－ＯＨ値が０．１８／ｍｍ未満、歪点が７３５℃以上であることを特徴とするガラス基板。 50 to 70% of SiO 2 , 10 to 25% of Al 2 O 3 , 0 to 10% of B 2 O 3 , 0 to 10% of MgO, 0 to 15% of CaO, 0 to 10% of SrO, by mass percentage A glass substrate comprising 0 to 15% Na 2 O 0.005 to 0.3%, having a β-OH value of less than 0.18 / mm, and a strain point of 735 ° C. or higher.
  2. 質量百分率で、Ｆｅ２Ｏ３を０．００５～０．１％含有することを特徴とする請求項１に記載のガラス基板。 The glass substrate according to claim 1, wherein the content of Fe 2 O 3 is 0.005 to 0.1% by mass percentage.
  3. 質量百分率で、ＳｎＯ２を０．００１～０．５％含有することを特徴とする請求項1又は２に記載のガラス基板。 3. The glass substrate according to claim 1, which contains 0.001 to 0.5% of SnO 2 by mass percentage.
  4. ヤング率が８０ＧＰａ以上であることを特徴とする請求項１～３のいずれかに記載のガラス基板。 The glass substrate according to any one of claims 1 to 3, which has a Young's modulus of 80 GPa or more.
  5. 熱収縮率が２０ｐｐｍ以下であることを特徴とする請求項１～４のいずれかに記載のガラス基板。 The glass substrate according to any one of claims 1 to 4, which has a thermal contraction rate of 20 ppm or less.
  6. 短辺が１５００ｍｍ以上、長辺が１８５０ｍｍ以上の寸法を有することを特徴とする請求項１～５のいずれかに記載のガラス基板。 The glass substrate according to any one of claims 1 to 5, wherein the short side has a dimension of 1500 mm or more and the long side has a dimension of 1850 mm or more.
  7. 厚みが０．７ｍｍ以下であることを特徴とする請求項１～６のいずれかに記載のガラス基板。 The glass substrate according to any one of claims 1 to 6, which has a thickness of 0.7 mm or less.
  8. 少なくとも一方の表面が微細凹凸面であることを特徴とする請求項１～７のいずれかに記載のガラス基板。 The glass substrate according to any one of claims 1 to 7, wherein at least one surface is a fine uneven surface.
  9. 微細凹凸面の表面粗さＲａが０．１～１０ｎｍであることを特徴とする請求項８に記載のガラス基板。 9. The glass substrate according to claim 8, wherein the surface roughness Ra of the fine uneven surface is 0.1 to 10 nm.
  10. 質量百分率で、ＳｉＯ２　５０～７０％、Ａｌ２Ｏ３　１０～２５％、Ｂ２Ｏ３　０％以上３％未満、ＭｇＯ　０～１０％、ＣａＯ　０～１５％、ＳｒＯ　０～１０％、ＢａＯ　０～１５％、Ｎａ２Ｏ　０．００５～０．３％を含有するガラスとなるように調製されたガラスバッチを準備する原料準備工程、ガラスバッチを電気溶融炉で溶融する溶融工程、溶融ガラスを板状に成形する成形工程、板状のガラスを徐冷炉で徐冷する徐冷工程、徐冷した板状ガラスを所定寸法に切断する加工工程を含み、β－ＯＨ値が０．１８／ｍｍ未満、歪点が７３５℃以上のガラス基板を得ることを特徴とするガラス基板の製造方法。 50 to 70% of SiO 2 , 10 to 25% of Al 2 O 3 , 0 to 10% of B 2 O 3 , 0 to 10% of MgO, 0 to 15% of CaO, 0 to 10% of SrO, by mass percentage Raw material preparation step of preparing a glass batch prepared to be a glass containing 0 to 15% Na 2 O 0.005 to 0.3%, melting step of melting the glass batch in an electric melting furnace, molten glass And forming the plate-like glass in an annealing furnace, and a processing step of cutting the plate-like glass into a predetermined size, and having a β-OH value of 0.18 / mm. A method for producing a glass substrate, comprising obtaining a glass substrate having a strain point of 735 ° C. or less.
  11. 徐冷工程における板状ガラスの冷却速度が、徐冷点から（徐冷点－１００℃）の温度範囲で５０℃／分～１０００℃／分の平均冷却速度であることを特徴とする請求項１０に記載のガラス基板の製造方法。 The cooling rate of the sheet glass in the annealing step is an average cooling rate of 50 ° C./min to 1000 ° C./min within the temperature range from the annealing point to (annealing point −100 ° C.) The manufacturing method of the glass substrate as described in 10.
  12. 少なくとも一方の表面を化学エッチングすることを特徴とする請求項１０又は１１に記載のガラス基板の製造方法。 The method for producing a glass substrate according to claim 10, wherein at least one surface is chemically etched.
  13. 少なくとも一方の表面を物理的研磨することを特徴とする請求項１０又は１１に記載のガラス基板の製造方法。 The method for producing a glass substrate according to claim 10, wherein at least one surface is physically polished.
  14. 表面粗さＲａを０．１～１０ｎｍにすることを特徴とする請求項１２又は１３に記載のガラス基板の製造方法。
          14. The method for producing a glass substrate according to claim 12, wherein the surface roughness Ra is 0.1 to 10 nm.
PCT/JP2018/048458 2018-01-23 2018-12-28 Glass substrate and method for manufacturing same WO2019146379A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
KR1020207010355A KR102516142B1 (en) 2018-01-23 2018-12-28 Glass substrate and its manufacturing method
CN201880087482.5A CN111630010A (en) 2018-01-23 2018-12-28 Glass substrate and method for manufacturing same
JP2019567947A JP7256473B2 (en) 2018-01-23 2018-12-28 Glass substrate and manufacturing method thereof

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2018-008672 2018-01-23
JP2018008672 2018-01-23

Publications (1)

Publication Number Publication Date
WO2019146379A1 true WO2019146379A1 (en) 2019-08-01

Family

ID=67395915

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2018/048458 WO2019146379A1 (en) 2018-01-23 2018-12-28 Glass substrate and method for manufacturing same

Country Status (5)

Country Link
JP (1) JP7256473B2 (en)
KR (1) KR102516142B1 (en)
CN (1) CN111630010A (en)
TW (1) TWI758576B (en)
WO (1) WO2019146379A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021131668A1 (en) * 2019-12-23 2021-07-01 日本電気硝子株式会社 Glass substrate manufacturing method and glass substrate
CN114080369A (en) * 2019-08-14 2022-02-22 日本电气硝子株式会社 Glass substrate
WO2022038976A1 (en) * 2020-08-19 2022-02-24 日本電気硝子株式会社 Glass sheet manufacturing method
JP7392909B2 (en) 2019-11-25 2023-12-06 日本電気硝子株式会社 Glass substrate for magnetic recording media and magnetic recording device using the same

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005255478A (en) * 2004-03-12 2005-09-22 Nippon Electric Glass Co Ltd Glass substrate
JP2015013800A (en) * 2010-03-23 2015-01-22 日本電気硝子株式会社 Glass substrate
WO2016185976A1 (en) * 2015-05-18 2016-11-24 日本電気硝子株式会社 Non-alkali glass substrate
WO2016194693A1 (en) * 2015-06-02 2016-12-08 日本電気硝子株式会社 Glass
WO2017122576A1 (en) * 2016-01-12 2017-07-20 日本電気硝子株式会社 Glass

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101654753B1 (en) * 2011-12-28 2016-09-08 아반스트레이트 가부시키가이샤 Glass substrate for flat panel displays and method for manufacturing same
JP7004488B2 (en) 2015-03-10 2022-01-21 日本電気硝子株式会社 Glass substrate
KR102403524B1 (en) 2016-08-23 2022-05-31 에이지씨 가부시키가이샤 alkali free glass
JP6953944B2 (en) 2017-09-21 2021-10-27 Ａｇｃ株式会社 Borosilicate glass and its manufacturing method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005255478A (en) * 2004-03-12 2005-09-22 Nippon Electric Glass Co Ltd Glass substrate
JP2015013800A (en) * 2010-03-23 2015-01-22 日本電気硝子株式会社 Glass substrate
WO2016185976A1 (en) * 2015-05-18 2016-11-24 日本電気硝子株式会社 Non-alkali glass substrate
WO2016194693A1 (en) * 2015-06-02 2016-12-08 日本電気硝子株式会社 Glass
WO2017122576A1 (en) * 2016-01-12 2017-07-20 日本電気硝子株式会社 Glass

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114080369A (en) * 2019-08-14 2022-02-22 日本电气硝子株式会社 Glass substrate
CN114080369B (en) * 2019-08-14 2024-01-05 日本电气硝子株式会社 Glass substrate
JP7392909B2 (en) 2019-11-25 2023-12-06 日本電気硝子株式会社 Glass substrate for magnetic recording media and magnetic recording device using the same
WO2021131668A1 (en) * 2019-12-23 2021-07-01 日本電気硝子株式会社 Glass substrate manufacturing method and glass substrate
CN114845962A (en) * 2019-12-23 2022-08-02 日本电气硝子株式会社 Method for producing glass substrate and glass substrate
WO2022038976A1 (en) * 2020-08-19 2022-02-24 日本電気硝子株式会社 Glass sheet manufacturing method

Also Published As

Publication number Publication date
TWI758576B (en) 2022-03-21
KR20200110299A (en) 2020-09-23
TW201936533A (en) 2019-09-16
JP7256473B2 (en) 2023-04-12
JPWO2019146379A1 (en) 2020-11-19
KR102516142B1 (en) 2023-03-29
CN111630010A (en) 2020-09-04

Similar Documents

Publication Publication Date Title
WO2019146379A1 (en) Glass substrate and method for manufacturing same
JP5679513B2 (en) Glass substrate and manufacturing method thereof
JP5780487B2 (en) Manufacturing method of glass substrate
TWI391357B (en) Alkali free glass and alkali free glass substrate
EP2426094B1 (en) Glass plate for display panels, process for producing it, and process for producing TFT panel
US6313052B1 (en) Glass for a substrate
WO2015005235A1 (en) Glass
JP4378769B2 (en) Glass substrate
JP2004091244A (en) Alkali-free glass substrate and method for manufacturing the same
JP7107361B2 (en) Alkali-free glass
JP6977718B2 (en) Alkaline-free glass
JP7396413B2 (en) glass
JP2002029776A (en) Nonalkali glass excellent in crack resistance
TW202039390A (en) Alkali-free glass
TW202031613A (en) Alkali-free glass
JP2008013434A (en) Nonalkali glass excellent in crack resistance
TW202039388A (en) Alkali-free glass
KR20160023698A (en) Alkali-free glass
JPWO2015041246A1 (en) Alkali-free glass
WO2014208523A1 (en) Alkali-free glass
CN114080369B (en) Glass substrate
WO2024122539A1 (en) Alkali-free glass plate
WO2014208524A1 (en) Alkali-free glass
CN116075487A (en) Method for producing low alkali glass plate and low alkali glass plate
TW202325673A (en) Alkali-free glass

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 18902943

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2019567947

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 18902943

Country of ref document: EP

Kind code of ref document: A1