Glass

Abstract

An object of the present invention is to provide a glass capable of suppressing deformation such as warpage of a glass substrate, having excellent formability, imposing a low burden on production equipment, and facilitating production of a large and thin glass substrate.SOLUTION: The glass of the present invention has a density, a Young's modulus, a strain point, a temperature T4 at which the glass viscosity becomes 104 dPa·s, a glass surface devitrification temperature (Tc), and a thermal expansion coefficient within predetermined ranges, and the contents of at least one alkali metal oxide selected from the group consisting of SiO2, Al2O3, Li2O, Na2O, and K2O, and P2O5 are within predetermined ranges.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a glass suitable for use as a glass substrate for various displays, photomasks, electronic device supports, information recording media, planar antennas, and the like. [Background technology]

[0002] Glass plates (glass substrates) for various displays, photomasks, electronic device supports, information recording media, and flat antennas, particularly glass used for glass plates on whose surfaces thin films of metals, oxides, etc. are formed, are required to have the following properties (1) to (4): (1) When the glass contains an alkali metal oxide, the alkali metal ions diffuse into the thin film and deteriorate the film properties of the thin film, so the glass must be substantially free of alkali metal ions. (2) The strain point must be high enough to minimize deformation of the glass sheet and shrinkage (thermal shrinkage) associated with structural stabilization of the glass when the glass sheet is exposed to high temperatures during the thin film formation process.

[0003] (3) Sufficient chemical resistance to the various chemicals used in semiconductor formation. x and SiN x It must be resistant to buffered hydrofluoric acid (BHF: a mixture of hydrofluoric acid and ammonium fluoride) used in etching, chemical solutions containing hydrochloric acid used in ITO etching, various acids (nitric acid, sulfuric acid, etc.) used in etching metal electrodes, and alkalis used in resist stripping solutions. (4) There are no internal or surface defects (bubbles, striae, inclusions, pits, scratches, etc.).

[0004] In addition to the above requirements, the following requirements (5) to (9) have also been made in recent years. (5) Lightweight displays are required, so glass with a low specific gravity is desirable. (6) Lighter displays are required, so thinner glass plates are desired. (7) In addition to the conventional amorphous silicon (a-Si) type LCD displays, polycrystalline silicon (p-Si) type LCD displays, which require high heat treatment temperatures, are now being manufactured (a-Si heat treatment temperature: approximately 350°C, p-Si heat treatment temperature: 350-550°C), so heat resistance is required.

[0005] (8) Glass with a small average thermal expansion coefficient is required to increase productivity by increasing the temperature rise and fall rate during heat treatment in the production of liquid crystal displays, and to improve thermal shock resistance. However, if the average thermal expansion coefficient of glass is too small, the number of film formation processes, such as those for gate metal films and gate insulating films, during the production of liquid crystal displays increases, resulting in problems such as cracks and scratches during transportation of the liquid crystal displays and significant deviations in the exposure pattern. (9) Furthermore, as glass substrates become larger and thinner, there is a demand for glass with a high specific modulus of elasticity (Young's modulus / density).

[0006] In order to satisfy the above-mentioned requirements, various glass compositions have been proposed for glass for liquid crystal display panels (see Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent No. 5702888 [Patent Document 2] International Publication No. 2013 / 183626 [Patent Document 3] Japanese Patent No. 5849965 [Patent Document 4] Japanese Patent No. 5712922 Summary of the Invention [Problem to be solved by the invention]

[0008] In recent years, electronic displays have become increasingly high-resolution, and as the definition of large-screen televisions increases, the thickness of Cu wiring, for example, increases, which makes it easier for substrates to warp due to the various film formation processes.Therefore, there is a growing need for substrates with less warpage, and to meet this need, it is necessary to increase the Young's modulus of glass. However, the known glasses with high Young's modulus as described in Patent Documents 3 and 4 have high strain points and viscosities of 10 4 The devitrification temperature tends to be higher than the temperature T4 at which the glass becomes dPa·s. As a result, it becomes difficult to mold the glass, which places a heavy load on the manufacturing equipment, raising concerns about increased production costs.

[0009] An object of the present invention is to provide glass that can suppress deformation such as warping of a glass substrate, has excellent formability, places a low burden on manufacturing equipment, and facilitates the manufacture of large, thin glass substrates. [Means for solving the problem]

[0010] The glass of the present invention that achieves the above object has a density of 2.60 g / cm 3 Below, Young's modulus is 88 GPa or more, strain point is 650 to 720 ° C, glass viscosity is 10 4 The temperature T4 at which the glass surface becomes dPa·s is 1320°C or lower, and the glass surface devitrification temperature (T c ) is T4+20℃ or less, and the average thermal expansion coefficient at 50 to 350℃ is 30×10 -7 ~43×10 -7 / °C, and contains, in mole % on an oxide basis, 50 to 80% SiO2, 8 to 20% Al2O3, 0 to 0.5% in total of at least one alkali metal oxide selected from the group consisting of Li2O, Na2O and K2O, and 0 to 1% P2O5.

[0011] In one embodiment of the alkali-free glass of the present invention, the specific modulus of elasticity may be 34 MN·m / kg or more.

[0012] In one embodiment of the alkali-free glass of the present invention, the glass surface devitrification viscosity (η c ) is 10 3.8It may be dPa·s or more.

[0013] In one embodiment of the alkali-free glass of the present invention, the viscosity is 10 2 The temperature T2 at which the viscosity becomes dPa·s may be 1680°C or lower.

[0014] In one embodiment of the alkali-free glass of the present invention, the glass transition point may be 730 to 790°C.

[0015] One embodiment of the alkali-free glass of the present invention is a glass in which, expressed in mole percent based on oxides, SiO2 50-80%, Al2O3 8-20%, B2O3 0-5% MgO 0-15% CaO 0-12%, SrO 0-10% BaO 0-10%, Na2O 0.005-0.2%, F 0.001 to 0.5%, P2O5 0-1%, Contains 0 to 0.5% in total of at least one alkali metal oxide selected from the group consisting of Li2O, Na2O, and K2O, The content of MgO+CaO+SrO+BaO may be 18 to 22%.

[0016] One embodiment of the alkali-free glass of the present invention may contain, in mole percent on an oxide basis, 0.1 to 15% MgO and 1 to 12% CaO, with an MgO / CaO ratio of 0.7 to 1.33.

[0017] In one embodiment of the alkali-free glass of the present invention, the β-OH value is 0.1 to 0.6 mm -1 may be.

[0018] In one embodiment of the alkali-free glass of the present invention, the value represented by the following formula (I) may be 4.10 or more. (7.87[Al2O3]-8.5[B2O3]+11.35[MgO]+7.09[CaO]+5.52[SrO]-1.45[BaO]) / [SiO2]···Equation (I)

[0019] In one embodiment of the alkali-free glass of the present invention, the value represented by the following formula (II) may be 0.95 or more. {-1.02[Al2O3]+10.79[B2O3]+2.84[MgO]+4.12[CaO]+5.19[SrO]+3.16[BaO] +11.07×([Li2O]+[Na2O]+[K2O])+3.954[F]+5.677[β-OH]} / [SiO2]...Formula (II)

[0020] In one embodiment of the alkali-free glass of the present invention, the value represented by the following formula (III) may be 5.5 or less. (8.9[Al2O3]+4.26[B2O3]+11.3[MgO]+4.54[CaO]+0.1[SrO]-9.98[BaO])×{1+([MgO] / [CaO]-1) 2} / [SiO2]...Formula (III)

[0021] In one embodiment of the alkali-free glass of the present invention, SnO2 may be contained in an amount of 0.5% or less, expressed in mole percent on an oxide basis.

[0022] In one embodiment of the alkali-free glass of the present invention, the compaction may be 100 ppm or less.

[0023] In one embodiment of the alkali-free glass of the present invention, the equivalent cooling rate may be 5 to 500° C. / min.

[0024] One embodiment of the alkali-free glass of the present invention may be a glass plate having at least one side measuring 1800 mm or more and a thickness of 0.7 mm or less.

[0025] An embodiment of the alkali-free glass of the present invention may be produced by a float process or a fusion process.

[0026] The display panel of the present invention comprises the glass of the present invention.

[0027] The semiconductor device of the present invention also comprises the glass of the present invention.

[0028] The information recording medium of the present invention comprises the glass of the present invention.

[0029] The planar antenna of the present invention comprises the glass of the present invention. [Effects of the Invention]

[0030] According to the present invention, it is possible to provide glass that can suppress deformation such as warping of the glass substrate, has excellent formability, places a low burden on manufacturing equipment, and facilitates the manufacturing of large, thin glass substrates. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the embodiments described below. In the following, the composition range of each component of the glass is expressed in mole percent based on the oxide. In the following, the numerical range indicated as "numerical value A to numerical value B" indicates a range that includes numerical value A and numerical value B as the minimum and maximum values, respectively, and means numerical value A or more and numerical value B or less.

[0032] First, the composition of the glass of this embodiment will be described. If the SiO2 content is less than 50 mol% (hereinafter simply referred to as %), the strain point does not rise sufficiently, and the average thermal expansion coefficient increases, tending to increase the specific gravity. Therefore, the SiO2 content is 50% or more, preferably 62% or more, more preferably 62.5% or more, even more preferably 63% or more, particularly preferably 63.5% or more, and most preferably 64% or more. If the SiO2 content exceeds 80%, the melting property of the glass tends to decrease, the Young's modulus tends to decrease, and the devitrification temperature tends to increase. Therefore, the SiO2 content is 80% or less, preferably 70% or less, more preferably 68% or less, even more preferably 67% or less, particularly preferably 66% or less, and most preferably 65.7% or less.

[0033] Al2O3 increases Young's modulus, suppressing deflection, suppressing phase separation of glass, lowering the average thermal expansion coefficient, raising the strain point, and improving fracture toughness, thereby increasing glass strength. If the Al2O3 content is less than 8%, these effects are less likely to be achieved, and the other components that increase the average thermal expansion coefficient tend to increase relatively, resulting in a higher average thermal expansion coefficient. Therefore, the Al2O3 content is 8% or more, preferably 10% or more, more preferably 12% or more, even more preferably 12.5% ​​or more, particularly preferably 12.8% or more, and most preferably 13% or more. If the Al2O3 content exceeds 20%, the melting property of the glass may deteriorate and the devitrification temperature may increase, so the Al2O3 content is 20% or less, preferably 16.5% or less, more preferably 16% or less, even more preferably 15% or less, particularly preferably 14.5% or less, and most preferably 14% or less.

[0034] Although B2O3 is not an essential component, it improves BHF resistance, enhances the melting reactivity of glass, and lowers the devitrification temperature, so it may be contained in an amount of 6% or less. The B2O3 content is 6% or less, preferably 5% or less, and more preferably 3% or less. Since B2O3 reduces the Young's modulus, the B2O3 content is more preferably 2.5% or less, more preferably 2.2% or less, even more preferably 2% or less, particularly preferably 1.7% or less, and most preferably 1.5% or less.

[0035] Although MgO is not an essential component, it can be added to increase the Young's modulus without increasing the specific gravity, thereby increasing the specific elastic modulus and suppressing deflection, and also to improve the fracture toughness and increase the glass strength. MgO also improves solubility. If the MgO content is less than 1%, these effects are not readily apparent, and the thermal expansion coefficient may become too low. Therefore, the MgO content is preferably 1% or more, more preferably 7% or more, even more preferably 8% or more, particularly preferably 8.2% or more, and most preferably 8.5% or more. However, if the MgO content is too high, the devitrification temperature tends to increase, so the MgO content is preferably 15% or less, more preferably 13% or less, even more preferably 10% or less, and particularly preferably 9.7% or less.

[0036] Although CaO is not an essential component, it can be added because, among alkaline earth metals, it has the characteristic of increasing the specific elastic modulus second only to MgO without excessively lowering the strain point, and like MgO, it also improves solubility. Furthermore, CaO is less likely to increase the devitrification temperature than MgO. If the CaO content is less than 1%, these effects are less likely to be achieved. Therefore, the CaO content is preferably 1% or more, more preferably 6% or more, even more preferably 7% or more, particularly preferably 8% or more, and most preferably 8.5% or more. If the CaO content exceeds 12%, the average thermal expansion coefficient becomes too high and the devitrification temperature becomes too high, making the glass more susceptible to devitrification during production. Therefore, the CaO content is preferably 12% or less, more preferably 10.5% or less, and even more preferably 10% or less.

[0037] Although SrO is not an essential component, it can be added because it improves the melting point of the glass without increasing the devitrification temperature. However, if the SrO content is less than 0.5%, these effects are unlikely to be achieved. Therefore, the SrO content is preferably 0.5% or more, more preferably 1% or more, even more preferably 1.2% or more, and particularly preferably 1.5% or more. Since SrO has a lower effect than BaO, and an excessively high SrO content would result in an increase in specific gravity and an excessively high average thermal expansion coefficient, the SrO content is preferably 10% or less, more preferably 4% or less, even more preferably 3% or less, and particularly preferably 2% or less.

[0038] Although BaO is not an essential component, it may be contained in the glass of this embodiment because it improves the melting point without increasing the devitrification temperature of the glass. However, an excessive BaO content tends to increase the specific gravity, decrease the Young's modulus, and make the average thermal expansion coefficient too large. Therefore, the BaO content is preferably 10% or less, more preferably 0.5% or less. It is even more preferable that the glass of this embodiment does not substantially contain BaO. In this specification, "substantially not containing" means that no impurities other than those unavoidable from raw materials, etc. are contained, that is, BaO is not intentionally contained. In this embodiment, when BaO is substantially not contained, the BaO content is, for example, 0.3% or less, and preferably 0.2% or less.

[0039] If the total amount of alkaline earth metal oxides, i.e., MgO + CaO + SrO + BaO (hereinafter also referred to as "RO"), is small, the devitrification temperature becomes high, that is, the devitrification viscosity becomes low, and formability deteriorates. Therefore, RO is set to 18% or more. If the RO content is too high, the average thermal expansion coefficient may become large and the acid resistance may become poor, so the RO content is 22% or less, preferably 20.7% or less, and more preferably 20.5% or less.

[0040] Furthermore, when the MgO content is 1% or more and the CaO content is 1% or more, if the ratio of the MgO content to the CaO content, i.e., MgO / CaO, is small, CaO-Al2O3-SiO2 crystals are likely to precipitate, resulting in poor formability. Specifically, the devitrification temperature becomes high, i.e., the devitrification viscosity becomes low. Therefore, the MgO / CaO ratio is 0.7 or more, preferably 0.8 or more, more preferably 0.85 or more, even more preferably 0.9 or more, and particularly preferably 0.92 or more. However, if the MgO / CaO ratio is too large, MgO-Al2O3-SiO2 crystals are likely to precipitate, resulting in a high devitrification temperature, i.e., a low devitrification viscosity. Therefore, the MgO / CaO ratio is 1.33 or less, preferably 1.3 or less, more preferably 1.25 or less, even more preferably 1.2% or less, particularly preferably 1.1% or less, and most preferably 1.05% or less.

[0041] In the glass of the present embodiment, alkali metal oxides are inevitably contained due to raw material impurities, and the inclusion of a very small amount of alkali metal oxides is permitted for the purpose of improving solubility. However, when the glass of this embodiment is used as the TFT-side substrate of a flat panel display, if the content of alkali metal oxide is too high, the migration of alkali ions into the TFT element becomes significant, causing the transistor characteristics to become unstable and reliability to be lost, and therefore the content must be kept within an appropriate range. Furthermore, when the glass of this embodiment is used as a semiconductor support substrate, if the content of alkali metal oxide is too high, there is a risk that alkali ions will diffuse into the silicon-containing substrate in the heat treatment step of bonding the silicon-containing substrate and the glass substrate together. Therefore, the total amount of alkali metal oxides, i.e., Li2O + Na2O + K2O (hereinafter also referred to as "R'2O"), is 0.5% or less, preferably 0.2% or less, more preferably 0.1% or less, more preferably 0.08% or less, even more preferably 0.05% or less, and most preferably 0.03% or less.

[0042] However, because Na2O has the effect of lowering the strain point of the glass, it can be contained within a range that does not cause the above-mentioned problems. In order to obtain the effect of lowering the strain point of the glass, the Na2O content is preferably 0.005% or more, more preferably 0.01% or more, particularly preferably 0.015% or more, and most preferably 0.02% or more. However, if the Na2O content is too high, the above-mentioned problems may occur, so the Na2O content is preferably 0.5% or less, more preferably 0.2% or less, even more preferably 0.1% or less, still more preferably 0.08% or less, particularly preferably 0.05% or less, and most preferably 0.03% or less.

[0043] Although F is not an essential component, it can be added because it has the effect of lowering the strain point of the glass. To obtain the effect of lowering the strain point of the glass, the F content is preferably 0.001% or more, more preferably 0.01% or more. There is no particular upper limit for the F content, but it is preferably 1.5% or less (0.43% or less by mass), and more preferably 0.7% or less.

[0044] If glass contains a large amount of P2O5, it may have poor water resistance, be prone to striae, and have poor uniformity. Also, if the glass is used as a display, a large amount of P in the glass may cause problems such as leakage current in the TFT. Therefore, the P2O5 content of the glass of this embodiment is 1% or less. The glass of this embodiment preferably does not substantially contain P2O5. In this embodiment, when the glass does not substantially contain P2O5, the P2O5 content is, for example, 0.01% or less, and preferably 0.005% or less.

[0045] Furthermore, to facilitate recycling of the glass, it is preferable that the glass of this embodiment be substantially free of PbO, As2O3, and Sb2O3. In this embodiment, when the glass is substantially free of PbO, As2O3, and Sb2O3, the contents of PbO, As2O3, and Sb2O3 are each, for example, 0.01% or less, and preferably 0.005% or less.

[0046] For the purpose of improving the meltability, clarity, formability, etc. of the glass, the glass of this embodiment may contain one or more of ZrO2, ZnO, Fe2O3, SO3, Cl, and SnO2 in a total amount of 2% or less, preferably 1% or less, and more preferably 0.5% or less. Of these, when SnO2 is added for the purpose of improving the meltability and clarity of the glass, the SnO2 content is preferably 0.5% or less (1.1% by mass or less).

[0047] The water content in glass lowers the strain point of the glass. The β-OH value of glass is used as an indicator of the water content in the glass. When the β-OH value of glass is 0.1 to 0.6 mm, -1 It is preferable to lower the strain point of the glass. -1 If the thickness is greater than 0.15mm, the generation of platinum interface bubbles cannot be suppressed. Platinum interface bubbles are generated when H2 passing through the wall of the molten glass channel made of platinum material reacts with the moisture in the molten glass to produce O2. The β-OH value of glass is 0.15 to 0.6mm. -1 More preferably, 0.2 to 0.45 mm -1 More preferably, 0.22 to 0.35 mm -1 is more preferable, and 0.25 to 0.3 mm -1 is more preferable. The β-OH value of the glass can be adjusted by various conditions during melting of the glass raw materials, such as the water content in the glass raw materials, the water vapor concentration in the melting tank, and the residence time of the glass melt in the melting tank. One method for adjusting the water content in the glass raw materials is to use hydroxides instead of oxides as glass raw materials (for example, to use magnesium hydroxide (Mg(OH)2) instead of magnesium oxide (MgO) as a magnesium source). In addition, methods for adjusting the water vapor concentration in the dissolution tank include using oxygen instead of air to burn fuels such as city gas or heavy oil to heat the dissolution tank, or using a mixture of oxygen and air.

[0048] The glass of the present embodiment preferably has a value represented by the following formula (I) of 4.10 or more. (7.87[Al2O3]-8.5[B2O3]+11.35[MgO]+7.09[CaO]+5.52[SrO]-1.45[BaO]) / [SiO2]···Equation (I) The value represented by formula (I) is an index of Young's modulus, and if this value is less than 4.10, the Young's modulus will be low. In the glass of this embodiment, the value represented by formula (I) is more preferably 4.15 or more, even more preferably 4.20 or more, particularly preferably 4.25 or more, and most preferably 4.30 or more. In the above formula (I), [Al2O3], [B2O3], [MgO], [CaO], [SrO], [BaO], and [SiO2] respectively represent the contents of Al2O3, B2O3, MgO, CaO, SrO, BaO, and SiO2 in mole percent on an oxide basis. The same applies to the following formulas (II) and (III).

[0049] In the glass of the present embodiment, the value represented by the following formula (II) is preferably 0.95 or more. {-1.02[Al2O3]+10.79[B2O3]+2.84[MgO]+4.12[CaO]+5.19[SrO]+3.16[BaO] +11.07×([Li2O]+[Na2O]+[K2O])+3.954[F]+5.677[β-OH]} / [SiO2]...Formula (II) The value represented by formula (II) is an index of the strain point, and if this value is less than 0.95, the strain point will be high. In the glass of this embodiment, the value represented by formula (II) is more preferably 1.0 or more, further preferably 1.05 or more, and particularly preferably 1.10 or more. In the above formula (II), [Li2O], [Na2O], [K2O], and [F] respectively represent the contents of Li2O, Na2O, K2O, and F expressed in mole percent on an oxide basis. In the above formula (II), [β-OH] is mm -1 means the β-OH value in units.

[0050] In the glass of the present embodiment, the value represented by the following formula (III) is preferably 5.5 or less. (8.9[Al2O3]+4.26[B2O3]+11.3[MgO]+4.54[CaO]+0.1[SrO]-9.98[BaO])×{1+([MgO] / [CaO]-1) 2} / [SiO2]...Formula (III) The value represented by formula (III) is an index of devitrification viscosity, and if this value exceeds 5.5, the devitrification viscosity becomes low. In the glass of this embodiment, the value represented by formula (III) is more preferably 5.1 or less, even more preferably 4.8 or less, particularly preferably 4.5 or less, and most preferably 4.30 or less.

[0051] The Young's modulus of the glass of this embodiment is 88 GPa or more. This suppresses deformation of the substrate due to external stress. For example, in the manufacture of a TFT-side substrate for a flat panel display, warping of the substrate is suppressed when a gate metal film such as copper or a gate insulating film such as silicon nitride is formed on the surface of the substrate. Deflection of the substrate is also suppressed. The Young's modulus is preferably 88.5 GPa or more, more preferably 89 GPa or more, even more preferably 89.5 GPa or more, particularly preferably 90 GPa or more, and most preferably 90.5 GPa or more. The Young's modulus can be measured by an ultrasonic method.

[0052] The density of the glass in this embodiment is 2.60 g / cm 3 This reduces the deflection due to its own weight, making it easier to handle when used as a large substrate. In addition, the device using the glass of this embodiment can be made lighter. The density is 2.59 g / cm 3 Less than 2.58 g / cm is more preferable. 3 More preferably, 2.57 g / cm 3 The following is particularly preferred: 2.56 g / cm 3 The following is most preferred. Note that a large substrate is, for example, a substrate with at least one side of 1800 mm or more. At least one side of the large substrate may be, for example, 2000 mm or more, 2500 mm or more, 3000 mm or more, or 3500 mm or more.

[0053] The glass of this embodiment has a strain point of 650 to 720°C. If the strain point is lower than 650°C, deformation of the glass plate and shrinkage (thermal shrinkage) associated with structural stabilization of the glass are likely to occur when the glass plate is exposed to high temperatures during the thin film formation process for displays. The strain point is preferably 685°C or higher, more preferably 690°C or higher, even more preferably 693°C or higher, particularly preferably 695°C or higher, and most preferably 698°C or higher. On the other hand, if the strain point is too high, the temperature of the annealing apparatus must be increased accordingly, which tends to shorten the life of the annealing apparatus. In addition, forming the glass becomes difficult, and there is a risk of increased thickness variation and surface waviness. The strain point is preferably 718°C or lower, more preferably 716°C or lower, even more preferably 714°C or lower, particularly preferably 712°C or lower, and most preferably 710°C or lower.

[0054] The glass of this embodiment has a viscosity of 10 4 The temperature T4 at which the viscosity reaches dPa·s is 1320°C or lower. This provides the glass of this embodiment with excellent formability. This also reduces the burden on manufacturing equipment. For example, the life of a float bath used to form the glass can be extended, improving productivity. T4 is preferably 1300°C or lower, more preferably 1290°C or lower, even more preferably 1285°C or lower, and particularly preferably 1280°C or lower. T4 is measured using a rotational viscometer according to the method specified in ASTM C 965-96, and the viscosity is 10 4 It can be calculated as the temperature at which the viscosity becomes d·Pa·s. In the examples described later, NBS710 and NIST717a were used as reference samples for calibrating the instrument.

[0055] The glass of this embodiment has a glass surface devitrification temperature (T c) is T4+20°C or less. This provides the glass of this embodiment with excellent formability. This also makes it possible to suppress the formation of crystals inside the glass during forming, which would otherwise cause a decrease in transmittance. This also makes it possible to reduce the burden on manufacturing equipment. For example, it is possible to extend the life of float baths used to form glass, thereby improving productivity. Glass surface devitrification temperature (T c ) is preferably T4+10°C or lower, more preferably T4+5°C or lower, even more preferably T4°C or lower, particularly preferably T4-1°C or lower, and most preferably T4-5°C or lower. Glass surface devitrification temperature (T c ) and glass internal devitrification temperature (T d The glass surface devitrification temperature (T) can be calculated as follows: crushed glass particles are placed in a platinum dish and heat-treated for 17 hours in an electric furnace controlled at a constant temperature. After the heat treatment, an optical microscope is used to measure the maximum temperature at which crystals precipitate on the glass surface and the minimum temperature at which crystals do not precipitate. The average of these values ​​is taken as the glass surface devitrification temperature (T). c Similarly, the maximum temperature at which crystals precipitate inside the glass and the minimum temperature at which crystals do not precipitate are measured, and the average value is taken as the glass internal devitrification temperature (T d ) The glass surface devitrification temperature (T c ) and glass internal devitrification temperature (T d The viscosity at each devitrification temperature is obtained by measuring the viscosity of the glass at each devitrification temperature.

[0056] The average thermal expansion coefficient of the glass of this embodiment at 50 to 350°C is 30 × 10 -7 / °C or more. For example, in the manufacture of a TFT-side substrate for a flat panel display, a gate metal film such as copper and a gate insulating film such as silicon nitride may be laminated in this order on glass. In this case, the average thermal expansion coefficient at 50 to 350°C is 30 × 10 -7 If the temperature is less than 100° C. / ° C., the difference in thermal expansion between the substrate and the gate metal film made of copper or the like formed on the substrate surface will be large, which may cause problems such as substrate warping and film peeling. The average thermal expansion coefficient between 50 and 350°C is 33 x 10 -7 / ℃ or more is preferable, 35 × 10 -7 / ℃ or more is more preferable, and 36×10 -7 / °C or more is more preferable, and 37 × 10 -7 / °C or more is particularly preferable, and 38 × 10 -7 / °C or more is most preferable. On the other hand, the average thermal expansion coefficient between 50 and 350°C is 43×10 -7 If the temperature exceeds 50°C / °F, the glass may break during the manufacturing process of products such as displays. Therefore, the average thermal expansion coefficient between 50 and 350°C is 43×10 -7 / ℃ or less. The average thermal expansion coefficient between 50 and 350°C is 42 x 10 -7 / ℃ or less is preferable, and 41.5 × 10 -7 / ℃ or less is more preferable, and 41×10 -7 / °C or less is more preferable, and 40.5 × 10 -7 / °C or less is particularly preferable, and 40.3 × 10 -7 / °C or less is most preferable.

[0057] The specific elastic modulus of the glass of this embodiment (Young's modulus (GPa) / density (g / cm 3 ) is preferably 34 MN·m / kg or more. This reduces the self-weight deflection and makes it easier to handle when made into a large substrate. The specific elastic modulus is more preferably 34.5 MN·m / kg or more, even more preferably 34.8 MN·m / kg or more, particularly preferably 35 MN·m / kg or more, and most preferably 35.2 MN·m / kg or more.

[0058] The glass surface devitrification temperature (T c The glass surface devitrification viscosity (η c ) is 10 3.8 dPa·s or more is preferable. This results in excellent formability of the glass substrate. This also makes it possible to suppress the formation of crystals inside the glass during forming, which would otherwise cause a decrease in transmittance. This also reduces the burden on manufacturing equipment. For example, it is possible to extend the life of float baths used to form glass substrates, thereby improving productivity. Glass surface devitrification viscosity (η c ) is preferably 10 3.85 dPa·s or more, more preferably 10 3.9dPa·s or more, particularly preferably 10 4 dPa·s or more, most preferably 10 4.05 It is dPa·s or more.

[0059] The viscosity of the glass of this embodiment is 10 2 The temperature T2 at which dPa·s is reached is preferably 1680°C or lower. This results in excellent glass melting properties. This also reduces the burden on manufacturing equipment. For example, the life of a furnace used to melt glass can be extended, improving productivity. This also reduces furnace-related defects (e.g., lumpy defects, Zr defects, etc.). T2 is more preferably 1670°C or lower, and even more preferably 1660°C or lower.

[0060] The glass transition point of the glass of this embodiment is preferably 730 to 790°C. A glass transition point of 730°C or higher results in excellent glass formability. For example, thickness deviation and surface waviness can be reduced. Furthermore, a glass transition point of 790°C or lower can reduce the burden on manufacturing equipment. For example, the surface temperature of the rolls used in glass forming can be lowered, thereby extending the life of the equipment and improving productivity. The glass transition point is more preferably 740°C or higher, even more preferably 745°C or higher, particularly preferably 750°C or higher, and most preferably 755°C or higher. On the other hand, the glass transition point is more preferably 785°C or lower, even more preferably 783°C or lower, particularly preferably 780°C or lower, and most preferably 775°C or lower.

[0061] The compaction of the glass of this embodiment is preferably 100 ppm or less, more preferably 90 ppm or less, even more preferably 80 ppm or less, even more preferably 75 ppm or less, particularly preferably 70 ppm or less, and most preferably 65 ppm or less. Compaction is the thermal shrinkage rate of glass that occurs due to relaxation of the glass structure during heat treatment. If the compaction is 100 ppm or less, it is possible to minimize dimensional changes associated with glass deformation and glass structural stabilization when exposed to high temperatures during thin film formation processes carried out in the manufacture of various displays. In this embodiment, compaction refers to compaction measured in the following procedure. A glass plate sample (100 mm long x 10 mm wide x 1 mm thick, mirror-polished with cerium oxide) obtained by processing the glass of this embodiment is held at a temperature of glass transition point + 120°C for 5 minutes, and then cooled to room temperature at 40°C per minute. Once the glass plate sample has cooled to room temperature, the total length (longitudinal direction) L1 of the sample is measured. The glass plate sample is then heated to 600°C at 100°C per hour, held at 600°C for 80 minutes, and cooled to room temperature at 100°C per hour. Once the glass plate sample has cooled to room temperature, the total length L2 of the sample is measured again. The ratio (L1-L2) / L1 of the difference in total length before and after heat treatment at 600°C to the total length L1 of the sample before heat treatment at 600°C is taken as the compaction value.

[0062] For the purpose of reducing compaction, the glass of this embodiment preferably has an equivalent cooling rate of, for example, 500°C / min or less. From the viewpoint of the balance between compaction and productivity, the equivalent cooling rate is preferably 5°C / min or more and 500°C / min or less. From the viewpoint of productivity, the equivalent cooling rate is more preferably 10°C / min or more, even more preferably 15°C / min or more, particularly preferably 20°C / min or more, and most preferably 25°C / min or more. From the viewpoint of compaction, the equivalent cooling rate is more preferably 300°C / min or less, even more preferably 200°C / min or less, particularly preferably 150°C / min or less, and most preferably 100°C / min or less. The equivalent cooling rate in this embodiment means an equivalent cooling rate measured by the following procedure. A number of rectangular parallelepiped samples for creating a calibration curve, each measuring 10 mm x 10 mm x 1 mm, were prepared by processing the glass of this embodiment, and these were held at the glass transition point +120°C for 5 minutes using an infrared heating electric furnace. Then, each sample was cooled to 25°C at different cooling rates ranging from 1°C / min to 1000°C / min. Next, the refractive index n of the d line (wavelength 587.6 nm) of each sample was measured using a precision refractometer KPR-2000 manufactured by Shimadzu Devices Corporation. d is measured by the V-block method.d By plotting against the logarithm of the cooling rate, the relationship between the cooling rate and n d Obtain a calibration curve. Next, the glass of this embodiment was processed into a rectangular parallelepiped shape of 10 mm x 10 mm x 1 mm, and n d is measured by the V-block method using a precision refractometer KPR-2000 manufactured by Shimadzu Devices Co., Ltd. d The cooling rate corresponding to the above is determined from the calibration curve and is used as the equivalent cooling rate.

[0063] The glass of this embodiment has a high Young's modulus of 88 GPa or more, which suppresses deformation of the substrate due to external stress, making it suitable for use as a glass plate used as a large substrate. A large substrate is, for example, a glass plate with at least one side of 1800 mm or more, and a specific example is a glass plate with a long side of 1800 mm or more and a short side of 1500 mm or more. The glass of the present embodiment is more preferably a glass plate having at least one side of 2400 mm or more, for example, a glass plate having a long side of 2400 mm or more and a short side of 2100 mm or more, more preferably a glass plate having at least one side of 3000 mm or more, for example, a glass plate having a long side of 3000 mm or more and a short side of 2800 mm or more, particularly preferably a glass plate having at least one side of 3200 mm or more, for example, a glass plate having a long side of 3200 mm or more and a short side of 2900 mm or more, and most preferably a glass plate having at least one side of 3300 mm or more, for example, a glass plate having a long side of 3300 mm or more and a short side of 2950 mm or more. The glass of this embodiment preferably has a thickness of 0.7 mm or less to achieve light weight. The thickness of the glass of this embodiment is more preferably 0.65 mm or less, even more preferably 0.55 mm or less, preferably 0.45 mm or less, and most preferably 0.4 mm or less. The thickness can be 0.1 mm or less, or even 0.05 mm or less, but from the viewpoint of preventing deflection under its own weight, the thickness is preferably 0.1 mm or more, more preferably 0.2 mm or more.

[0064] The glass of this embodiment can be produced, for example, by the following procedure. Glass raw materials are mixed to obtain a desired glass composition, charged into a melting furnace, and heated to 1500 to 1800°C to melt the mixture to obtain molten glass. The resulting molten glass is formed into a glass ribbon of a predetermined thickness in a forming device, and the glass ribbon is slowly cooled and then cut to obtain glass. In the production of the glass of this embodiment, in order to reduce compaction, it is preferable to cool the glass so that the equivalent cooling rate is 500° C. / min or less, for example.

[0065] In the production of the glass of this embodiment, it is preferable to form molten glass into a glass plate by a float process, a fusion process, etc. From the viewpoint of stably producing large plate glass (e.g., one side of 1800 mm or more) having a high Young's modulus, the float process is preferable.

[0066] Next, the display panel of this embodiment will be described. The display panel of this embodiment has the glass of this embodiment described above as a glass substrate. The display panel is not particularly limited as long as it has the glass of this embodiment, and may be any of various display panels such as a liquid crystal display panel or an organic EL display panel. Taking the example of a thin-film transistor liquid crystal display (TFT-LCD), it has a display surface electrode substrate (array substrate) on whose surface gate electrode lines and a gate insulating oxide layer are formed, and further, pixel electrodes are formed on the surface of the oxide layer, and a color filter substrate on whose surface RGB color filters and counter electrodes are formed, and a cell is formed by sandwiching a liquid crystal material between the paired array substrate and color filter substrate. In addition to such a cell, a liquid crystal display panel also includes other elements such as peripheral circuits. The liquid crystal display panel of this embodiment uses the glass of this embodiment for at least one of the pair of substrates that make up the cell.

[0067] The glass of this embodiment can be used, for example, as a glass plate for supporting an electronic device. When the glass of this embodiment is used as a glass plate for supporting an electronic device, a device-forming substrate such as a glass substrate, a silicon substrate, or a resin substrate is supported by being bonded directly or using an adhesive to the glass of this embodiment (glass plate for supporting an electronic device). Examples of the glass plate for supporting an electronic device include a supporting glass plate in the manufacturing process of a flexible display (e.g., an organic EL display) using a resin such as polyimide as a substrate, and a supporting glass plate for a resin-silicon chip composite wafer in the manufacturing process of a semiconductor package.

[0068] Next, the semiconductor device of this embodiment will be described. The semiconductor device of this embodiment has the glass of this embodiment described above as a glass substrate. Specifically, the semiconductor device of this embodiment has the glass of this embodiment as a glass substrate for image sensors such as MEMS, CMOS, and CIS. The semiconductor device of this embodiment also has the glass of this embodiment as a cover glass for a display device used for projection, for example, a cover glass for LCOS (Liquid Crystal on Silicon).

[0069] Next, the information recording medium of this embodiment will be described. The information recording medium of this embodiment has the glass of this embodiment described above as a glass substrate. Specific examples of the information recording medium include magnetic recording media and optical disks. Examples of the magnetic recording medium include energy-assisted magnetic recording media and perpendicular magnetic recording magnetic recording media.

[0070] Next, the planar antenna of this embodiment will be described. The planar antenna of this embodiment has the glass of this embodiment described above as a glass substrate. Specific examples of the planar antenna of this embodiment include planar liquid crystal antennas having a planar shape, such as liquid crystal antennas and microstrip antennas (patch antennas), which have good directivity and reception sensitivity. Liquid crystal antennas are disclosed, for example, in International Publication No. 2018 / 016398. Patch antennas are disclosed, for example, in Japanese Patent Application Laid-Open No. 2017-509266 and Japanese Patent Application Laid-Open No. 2017-063255. [Example]

[0071] Examples will be described below, but the present invention is not limited to these Examples. In the following, Examples 1 to 22 and Examples 29 to 49 are Examples, and Examples 23 to 28 are Comparative Examples. The raw materials for each component were mixed so that the glass composition would be the composition shown in Tables 1 to 7 (unit: mol %), and melted in a platinum crucible at 1600°C for 1 hour. After melting, the molten liquid was poured onto a carbon plate and held at a temperature of the glass transition point + 30°C for 60 minutes, after which it was cooled at 1°C per minute to room temperature (25°C) to obtain a plate-shaped glass. This was mirror-polished to obtain a glass plate, and various physical properties were measured. The results are shown in Tables 1 to 7. In Tables 1 to 7, the values ​​shown in parentheses are calculated values, and blanks indicate unmeasured values.

[0072] The methods for measuring each physical property are shown below. (β-OH value of glass) The absorbance of the glass sample for light with wavelengths of 2.75 to 2.95 μm was measured, and the maximum value β max The β-OH value of the glass is calculated by dividing the value by the thickness (mm) of the sample.

[0073] (average thermal expansion coefficient) Measurements were made using a differential thermal dilatometer (TMA) according to the method specified in JIS R3102 (1995). The measurement temperature range was from room temperature to 400°C or higher, and the average thermal expansion coefficient in the range of 50 to 350°C was calculated in units of 10. -7 The temperature was expressed as / °C. (density) According to the method specified in JIS Z 8807, the density of about 20 g of glass mass containing no bubbles was measured by the Archimedes method.

[0074] (distortion point) The strain point was measured by the fiber stretching method according to the method specified in JIS R3103-2 (2001). (glass transition temperature Tg) The glass transition temperature Tg was measured by the thermal expansion method using a differential thermal dilatometer (TMA) according to the method specified in JIS R3103-3 (2001). (Young's modulus) In accordance with the method specified in JIS Z 2280, the Young's modulus was measured by the ultrasonic pulse method for glass having a thickness of 0.5 to 10 mm.

[0075] (T2) The viscosity was measured using a rotational viscometer according to the method specified in ASTM C 965-96. 2 The temperature T2 (°C) at which the viscosity reached d·Pa·s was measured. (T4) The viscosity was measured using a rotational viscometer according to the method specified in ASTM C 965-96. 4 The temperature T4 (°C) at which the viscosity reached d·Pa·s was measured. (devitrification temperature) The glass was crushed and classified using a test sieve so that the particle size was in the range of 2 to 4 mm. The obtained glass cullet was ultrasonically cleaned in isopropyl alcohol for 5 minutes, washed with ion-exchanged water, dried, placed in a platinum dish, and heat-treated for 17 hours in an electric furnace controlled at a constant temperature. The heat treatment temperature was set at 10°C intervals. After heat treatment, the glass was removed from the platinum dish, and using an optical microscope, the maximum temperature at which crystals precipitated on the surface and inside of the glass and the minimum temperature at which crystals did not precipitate were measured. The maximum temperature at which crystals precipitated on the surface and inside of the glass and the minimum temperature at which crystals did not precipitate were each measured once (two times when it was difficult to determine whether crystals precipitated). The average of the maximum temperature at which crystals precipitated on the glass surface and the minimum temperature at which crystals did not precipitate was calculated to determine the glass surface devitrification temperature (T c Similarly, the average value of the maximum temperature at which crystals precipitate inside the glass and the minimum temperature at which crystals do not precipitate was calculated to obtain the glass internal devitrification temperature (T d ) was decided.

[0076] (specific elastic modulus) The specific elastic modulus was calculated by dividing the Young's modulus obtained by the above-mentioned procedure by the density. (devitrification viscosity) The glass surface devitrification temperature (T c ) and the glass surface devitrification temperature (T c ) and measure the glass surface devitrification viscosity (η c Similarly, the internal devitrification temperature (T d ) and the glass internal devitrification temperature (T d ) and measure the glass internal devitrification viscosity (η d ) was decided.

[0077] [Table 1]

[0078] [Table 2]

[0079] [Table 3]

[0080] [Table 4]

[0081] [Table 5]

[0082] [Table 6]

[0083] [Table 7]

[0084] In Example 23, the Young's modulus was low, being less than 88 GPa. (T c ) was higher than T4+20°C. Examples 25, 27, and 28 had high strain points. Example 26, which had an RO of over 22, had a large average thermal expansion coefficient of 43×10 -7 / ℃.

[0085] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2018-46854) filed on March 14, 2018, the entirety of which is incorporated by reference. All references cited herein are incorporated in their entirety. [Industrial Applicability]

[0086] The glass of the present invention having the above-mentioned characteristics is suitable for applications such as display substrates, photomask substrates, electronic device support substrates, information recording medium substrates, and flat antenna substrates.

Claims

1. Density is 2.60 g / cm ３ The strain point is 650 to 720°C, the glass viscosity is 10 ４ Temperature T at which viscosity becomes dPa s ４ is 1320°C or less, and the glass surface devitrification temperature (T ｃ ) is T ４ Average thermal expansion coefficient below +20°C and between 50 and 350°C is 30 x 10 －７ ~43 x 10 －７ / °C, The specific elastic modulus is 34 MN m / kg or more, In mole percent based on oxides SiO ２ 50 to 80% of Al ２ O ３ を8~20%、 MgO 0.1 to 15%, CaO 1 to 12% B ２ O ３ 1.5 to 5%, Li ２ O, Na ２ O and K ２ O, 0 to 0.5% in total of at least one alkali metal oxide selected from the group consisting of P ２ O ５ Contains 0 to 1% of MgO / CaO is 1.08 or more, A glass having a value represented by the following formula (III) of 5.1 or less. (8.9[Al ２ O ３ ) + 4.26[B ２ O ３ ) + 11.3[MgO] + 4.54[CaO] + 0.1[SrO] - 9.98[BaO]) × {1 + ([MgO] / [CaO] - 1) ２} / [SiO ２ ··· Formula (III)

2. 2. The glass of claim 1, having a Young's modulus of 88 GPa or greater.

3. Glass surface devitrification viscosity (η ｃ ) is 10 ３．８ 3. The glass according to claim 1, wherein the viscosity is dPa·s or more.

4. Viscosity is 10 ２ Temperature T at which viscosity becomes dPa s ２ The glass according to any one of claims 1 to 3, wherein the melting point is 1680°C or less.

5. 5. The glass according to claim 1, having a glass transition point of 730 to 790°C.

6. In mole percent based on oxides SrO 0 to 10%, BaO 0 to 10%, 6. The glass of claim 1, wherein MgO+CaO+SrO+BaO is 18 to 22%.

7. Na ２ Oを0.005~0.2%、 The glass according to any one of claims 1 to 6, containing 0.001 to 0.5% F.

8. β-OH value: 0.1 to 0.6 mm －１ The glass according to any one of claims 1 to 7, wherein

9. The glass according to any one of claims 1 to 8, wherein the value represented by the following formula (I) is 4.10 or more: (7.87[All ２ Oh ３ ]-8.5[B ２ Oh ３ ]+11.35[MO]+7.09[1O]+5.52[SrO]-1.45[BaO]) / [SiO ２ ]・・・form (I)

10. The glass according to any one of claims 1 to 9, wherein the value represented by the following formula (II) is 0.95 or more: {-1.02[Al ２ O ３ +10.79[B ２ O ３ +2.84[MgO]+4.12[CaO]+5.19[SrO]+3.16[BaO]+11.07×([Li ２ O]+[Na ２ O]+[K ２ O])+3.954[F]+5.677[β-OH]} / [SiO ２ ...Formula (II)

11. In mole percent based on oxide, SnO ２ The glass according to any one of claims 1 to 10, containing 0.5% or less of

12. 12. The glass according to claim 1, having a compaction of 100 ppm or less.

13. The glass according to any one of claims 1 to 12, having an equivalent cooling rate of 5 to 500°C / min.

14. The glass according to any one of claims 1 to 13, which is a glass plate having at least one side of 1800 mm or more and a thickness of 0.7 mm or less.

15. A display panel comprising the glass according to any one of claims 1 to 14.

16. A semiconductor device comprising the glass according to any one of claims 1 to 14.

17. An information recording medium comprising the glass according to any one of claims 1 to 14.

18. A planar antenna comprising the glass according to any one of claims 1 to 14.

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