Alkali-free glass

Abstract

To provide alkali-free glass with low dielectric loss tangent in the high-frequency range, low surface devitrification temperature, and excellent acid resistance and phase separation characteristics. [Solution] Alkali-free glass containing SiO2 50-78%, Al2O3 2-6%, B2O3 18-35%, MgO 1-6%, CaO 0-6%, SrO 0-6%, and BaO 0-3% in molar percentage based on oxides, where formula (A) is [MgO]+[CaO]+[SrO]+[BaO], and the value of formula (A) is 2% or more and 6% or less, and formula (B) is [Al2O3]-([MgO]+[CaO]+[SrO]+[BaO]), and the value of formula (B) is -3% or more and 2% or less.

Description

Technical Field

[0001] The present invention relates to an alkali-free glass. The present invention also relates to a glass plate containing such an alkali-free glass, a glass substrate for high-frequency devices, a panel antenna, window glass, vehicle window glass, and a cover glass for touch panels.

Background Art

[0002] There are electronic devices such as mobile phones, smartphones, portable information terminals, communication devices such as Wi-Fi devices, surface acoustic wave (SAW) devices, radar components, and antenna components. In such electronic devices, in order to increase the communication capacity and speed, the signal frequency is being increased. Insulating substrates such as resin substrates, ceramic substrates, and glass substrates are generally used for circuit boards used in high-frequency applications. For insulating substrates used in high-frequency devices, it is required to reduce transmission losses based on dielectric loss and conductor loss in order to ensure characteristics such as the quality and strength of high-frequency signals.

[0003] Among these insulating substrates, resin substrates have low rigidity due to their characteristics. Therefore, when rigidity (strength) is required for semiconductor package products, it is difficult to apply resin substrates. Ceramic substrates have the drawback that it is difficult to improve the surface smoothness, which tends to increase the conductor loss caused by the conductor formed on the substrate surface. On the other hand, glass substrates have high rigidity, making it easy to reduce the size and thickness of packages, excellent surface smoothness, and easy to increase the size of the substrate itself.

[0004] Patent Document 1 discloses a glass substrate for high-frequency devices with a dielectric tangent of 0.007 or less at 35 GHz.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, in addition to reducing the dielectric loss tangent in the high-frequency region, the glass substrate for the above applications is required to have excellent acid resistance. In the manufacturing process of circuit boards such as liquid crystal antennas and high-frequency devices, chemical cleaning is performed as a pretreatment before forming a wiring layer on the glass substrate. If the chemical resistance of the glass is low, for example, during acid cleaning, the surface of the substrate may dissolve and the smoothness of the substrate surface may be impaired, which may reduce the adhesion of the film formed on the substrate surface. In addition, there is also a risk that the eluate may adhere to the substrate surface. As a result, the conductor loss caused by the conductor formed on the substrate surface may increase.

[0007] In addition, the glass substrate for the above applications is required to have a low surface devitrification temperature in order to improve the glass quality and the productivity of the glass plate.

[0008] In addition, the glass substrate for the above applications is required to have excellent phase separation characteristics. If the glass has excellent phase separation characteristics, for example, when the glass substrate is acid-cleaned, it is possible to preferably prevent local unevenness from occurring on the substrate surface. As a result, the transmission loss of high-frequency signals can be reduced.

[0009] An object of the present invention is to provide an alkali-free glass having a low dielectric loss tangent in the high-frequency region, a low surface devitrification temperature, excellent acid resistance and phase separation characteristics.

Means for Solving the Problems

[0010] As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by the following configuration. [1] In terms of mol% based on oxides SiO2 50 to 80%, Al2O3 2 to 6%, B2O3 18 to 35%, MgO 1 to 6%, CaO 0-6%, SrO 0-6%, It contains BaO 0-3%, Equation (A) is [MgO]+[CaO]+[SrO]+[BaO], and the value of the above equation (A) is between 2% and 6%. Equation (B) is [Al2O3]-([MgO]+[CaO]+[SrO]+[BaO]), and the value of the above equation (B) is between -3% and 2%, making it alkali-free glass. [2] The alkali-free glass described in [1], wherein formula (C) is [SiO2] + [B2O3] and the value of formula (C) is 88% or more and 100% or less. [3] The alkali-free glass described in [1] or [2], wherein formula (C) is [SiO2] + [B2O3] and the value of formula (C) is 89.4% or more and 93% or less. [4] The alkali-free glass described in any of [1] to [3], wherein formula (D) is [Al2O3] / [B2O3] and the value of formula (D) is 0.1 or greater and 0.3 or less. [5] The alkali-free glass described in any of [1] to [4], wherein formula (E) is [MgO] / ([MgO]+[CaO]+[SrO]+[BaO]) and the value of the above formula (E) is 0.5 or greater. [6] The alkali-free glass described in any of [1] to [5], wherein formula (F) is ([MgO]+[CaO]+[SrO]+[BaO]) / [Al2O3] and the value of formula (F) is 0.5 or greater and 1.2 or less. [7] Alkali-free glass as described in any of [1] to [6], containing 0 to 0.5 mol% of Fe on an Fe2O3 basis. [8] The β-OH value of the glass is 0.05 mm -1 Above, 1.0 mm -1 Alkali-free glass as described in any of the following [1] to [7]. [9] An alkali-free glass according to any one of [1] to [8], containing a total of 0 to 0.4% of at least one selected from the group consisting of Li2O, Na2O, and K2O, expressed in mole percent on an oxide basis.

[10] The alkali-free glass described in [9], wherein formula (G) is [Li2O] / ([Li2O]+[Na2O]+[K2O]) and the value of formula (G) is 0.5 or greater.

[11] Alkali-free glass as described in any of [1] to

[10] , containing 0 to 0.5% SnO2 in mol% based on oxides.

[12] An alkali-free glass according to any one of [1] to

[11] , containing in total 0 to 1% in mole percent based on oxides at least one selected from the group consisting of Sc2O3, TiO2, ZnO, Ga2O3, GeO2, Y2O3, ZrO2, Nb2O5, In2O3, TeO2, HfO2, Ta2O5, WO3, Bi2O3, La2O3, Gd2O3, Yb2O3, and Lu2O3.

[13] Alkali-free glass according to any of [1] to

[12] , containing 0 to 1.5 mol% of F.

[14] Alkali-free glass as described in any of [1] to

[13] , wherein the dielectric loss tangent at 35 GHz is 0.005 or less.

[15] Density is 2.58 g / cm³ 3 The average thermal expansion coefficient at 50-350°C is 20 × 10⁻⁶. -7 / ℃~50×10 -7 Alkali-free glass as described in any of [1] to

[14] , with a temperature of / ℃.

[16] Glass viscosity is 10 2 The temperature T2 at which the viscosity is dPa·s is 1500-1900°C, and the glass viscosity is 10 4 Alkali-free glass as described in any of [1] to

[15] , wherein the temperature T4 at which dPa·s is obtained is 1290°C or less.

[17] Alkali-free glass according to any of [1] to

[16] , wherein the glass transition temperature is 700°C or less.

[18] Alkali-free glass as described in any of [1] to

[17] , wherein the surface devitrification temperature is 1400°C or less.

[19] A glass plate containing alkali-free glass as described in any of [1] to

[18] , having a main surface and an end surface, wherein at least one of the main surfaces has an arithmetic mean roughness Ra of 1.5 nm or less.

[20] A glass plate containing alkali-free glass as described in any of [1] to

[18] , having a main surface and an end surface, with at least one side measuring 1000 mm or more and a thickness of 0.7 mm or less.

[21] A glass plate as described in

[19] or

[20] , manufactured by the float or fusion method.

[22] A glass substrate for high-frequency devices containing alkali-free glass as described in any of [1] to

[18] .

[23] A panel antenna containing alkali-free glass as described in any of [1] to

[18] .

[24] Window glass containing alkali-free glass as described in any of [1] to

[18] .

[25] Vehicle window glass containing alkali-free glass as described in any of [1] to

[18] .

[26] A touch panel cover glass containing alkali-free glass as described in any of [1] to

[18] .

[27] expressed in mole percent based on oxides SiO2 50-78%, Al2O3 2-6%, B2O318~35%, MgO 1-6%, CaO 0-6%, SrO 0-6%, It contains BaO 0-3%, Equation (A) is [MgO]+[CaO]+[SrO]+[BaO], and the value of equation (A) is 2% or more and 6% or less. Equation (B) is [Al2O3]-([MgO]+[CaO]+[SrO]+[BaO]), and the value of equation (B) is between -3% and 2%, and is an alkali-free glass.

[28] The alkali-free glass described in

[27] , wherein formula (C) is [SiO2] + [B2O3] and the value of formula (C) is 88% or more and 96% or less. [Effects of the Invention]

[0011] The alkali-free glass of the present invention has a low dielectric loss tangent in the high-frequency range. Therefore, it can reduce dielectric loss of high-frequency signals and is suitable for glass substrates for high-frequency devices. Circuit boards using such glass substrates can reduce transmission loss of high-frequency signals and provide practical high-frequency devices such as electronic devices. The alkali-free glass of the present invention exhibits excellent acid resistance. Therefore, when glass substrates are acid-cleaned during the manufacturing process of circuit boards such as liquid crystal antennas and high-frequency devices, there is no risk of the substrate surface dissolving, deteriorating the smoothness of the substrate surface, or of leached substances adhering to the substrate surface. This prevents a decrease in the adhesion of films formed on the substrate surface. Furthermore, it prevents an increase in conductor loss. The alkali-free glass of the present invention can reduce the transmission loss of radio waves in the high frequency band. Therefore, it is suitable for glass products that transmit and receive radio waves in the high frequency band. The alkali-free glass of this invention has a low surface devitrification temperature. Therefore, it offers excellent glass quality and glass sheet productivity. The alkali-free glass of the present invention exhibits excellent phase separation characteristics. Therefore, for example, it can effectively prevent localized irregularities from forming on the substrate surface when a glass substrate is acid-cleaned. This reduces the transmission loss of high-frequency signals. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of the configuration of a circuit board for high-frequency devices. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described below. In the following description, numerical ranges indicated using "~" represent ranges that include the numerical values ​​before and after "~" as the minimum and maximum values, respectively. Unless otherwise specified, the content of each component in alkali-free glass and glass plates is given as mole percentage (mol%) based on oxides. In addition, the notation [metal oxide] in formulas (A) to (G) represents the mole percentage of the metal oxide component. For example, [MgO] represents the mole percentage of magnesium oxide. In this specification, "high frequency" means 10 GHz or higher, preferably greater than 30 GHz, more preferably 35 GHz or higher. It also means 3 THz or lower, preferably 1 THz or lower, more preferably 300 GHz or lower, and even more preferably 100 GHz or lower.

[0014] The alkali-free glass of the present invention (hereinafter sometimes simply referred to as "glass") will be described below.

[0015] If the SiO2 content as a network-forming material is 50 mol% (hereinafter simply referred to as %) or more, the dielectric loss tangent in the high-frequency range can be reduced, the glass-forming ability and acid resistance can be improved, and the rise in surface devitrification temperature can be suppressed. The SiO2 content is preferably 55% or more, more preferably 58% or more, even more preferably 60% or more, even more preferably 60.5% or more, and especially preferably 61% or more. Furthermore, if the SiO2 content is 80% or less, the solubility of the glass can be improved. The SiO2 content is preferably 78% or less, preferably 75% or less, more preferably 73% or less, even more preferably 71% or less, even more preferably 69% or less, especially preferably 67% or less, even more preferably 65% ​​or less, even more preferably 64% or less, even more preferably 63% or less, even more preferably 62.5% or less, and especially even more preferably 62% or less.

[0016] Al2O3 is a component that exhibits effects such as improving acid resistance, improving Young's modulus, improving the phase separation characteristics of glass, and lowering the coefficient of thermal expansion. If the Al2O3 content is 2% or more, the acid resistance and phase separation characteristics of glass are improved. The Al2O3 content is preferably 2.5% or more, more preferably 3% or more, even more preferably 3.5% or more, even more preferably 3.7% or more, and especially preferably 4% or more. Furthermore, if the Al2O3 content is 6% or less, the dielectric loss tangent in the high-frequency range can be lowered. The Al2O3 content is preferably 5.5% or less, more preferably 5% or less, and even more preferably 4.5% or less.

[0017] If the B2O3 content is 18% or more, solubility improves. Also, the dielectric loss tangent in the high-frequency range can be lowered. The B2O3 content is preferably 19% or more, more preferably 20% or more, even more preferably 21% or more, even more preferably 22% or more, especially preferably 23% or more, even more preferably 24% or more, even more preferably 25% or more, even more preferably 26% or more, even more preferably 27% or more, even more preferably 28% or more, even more preferably 28.5% or more, especially even more preferably 29% or more, especially preferably 29.5% or more, and most preferably 30% or more. In addition, if the B2O3 content is 35% or less, acid resistance can be improved. The B2O3 content is preferably 34% or less, more preferably 33% or less, even more preferably 32% or less, even more preferably 31.5% or less, especially preferably 31% or less, and even more preferably 30.5% or less.

[0018] MgO is a component that increases Young's modulus without increasing specific gravity. In other words, MgO is a component that increases the specific modulus of elasticity, thereby reducing the problem of deflection, improving fracture toughness, and increasing glass strength. MgO is also a component that improves solubility. If the MgO content is 1% or more, the effect of including MgO is obtained without lowering the coefficient of thermal expansion too much. In addition, the acid resistance of the glass is improved. The MgO content is preferably 2% or more, more preferably 2.5% or more, and even more preferably 3% or more. Furthermore, if the MgO content is 6% or less, the rise in surface devitrification temperature can be suppressed. The MgO content is preferably 5.4% or less, more preferably 5% or less, and even more preferably 4% or less.

[0019] CaO is a component that, among alkaline earth metals, has the second highest specific modulus after MgO, and does not excessively lower the strain point, and like MgO, it also improves solubility. Furthermore, it is a component that does not easily raise the surface devitrification temperature compared to MgO. Therefore, glass may contain CaO. If the CaO content is 6% or less, the average coefficient of thermal expansion will not become too high, and the rise in the surface devitrification temperature can be suppressed. The CaO content is preferably 5% or less, more preferably 4% or less, even more preferably 3% or less, even more preferably 2% or less, especially preferably 1% or less, even more preferably 0.8% or less, even more preferably 0.6% or less, and even more preferably 0.4% or less. If CaO is included, its content is preferably 0.1% or more, and more preferably 0.2% or more.

[0020] SrO is a component that improves solubility without increasing the surface devitrification temperature of glass. Therefore, glass may contain SrO. The SrO content is preferably 0.1% or more, more preferably 0.3% or more, and even more preferably 0.5% or more. If the SrO content is 6% or less, it is possible to suppress the average thermal expansion coefficient from becoming too high without increasing the specific gravity too much. The SrO content is preferably 5% or less, more preferably 4% or less, even more preferably 3% or less, even more preferably 2% or less, and especially preferably 1% or less.

[0021] BaO is a component that improves solubility without raising the surface devitrification temperature of glass. Therefore, glass may contain BaO. The BaO content is preferably 0.1% or more, and more preferably 0.2% or more. If the BaO content is high, the specific gravity increases, the Young's modulus decreases, and the average coefficient of thermal expansion tends to become too high. In addition, the acid resistance of the glass decreases. For this reason, the BaO content is preferably 3% or less, more preferably 2% or less, even more preferably 1% or less, even more preferably 0.8% or less, especially preferably 0.6% or less, and still most preferably 0.4% or less.

[0022] The alkali-free glass of the present invention has a total content of formula (A) that is 2% or more and 6% or less, where formula (A) is represented by [MgO] + [CaO] + [SrO] + [BaO]. If the value of equation (A) is 2% or higher, the rise in surface devitrification temperature can be suppressed. This improves the quality of the glass and increases productivity when manufacturing glass sheets. The value of formula (A) is preferably 2.5% or more, more preferably 3% or more, even more preferably 3.5% or more, and even more preferably 4% or more. If the value of equation (A) is 6% or less, the dielectric loss tangent in the high-frequency range can be reduced, improving the acid resistance and phase separation characteristics of the glass. The value of formula (A) is preferably 5.5% or less, more preferably 5% or less, and even more preferably 4.5% or less.

[0023] In the glass of the present invention, when formula (B) is an amount represented by [Al2O3]-([MgO]+[CaO]+[SrO]+[BaO]), the value of formula (B) is between -3% and 2%. If the value of equation (B) is -3% or greater, the acid resistance and phase separation properties of the glass will improve. The value of formula (B) is preferably -2.5% or more, more preferably -2% or more, even more preferably -1.5% or more, even more preferably -1% or more, and especially preferably -0.5% or more. If the value of equation (B) is 2% or less, the rise in surface devitrification temperature can be suppressed. This improves the quality of the glass and increases productivity when manufacturing glass sheets. The value of formula (B) is preferably 1.5% or less, more preferably 1% or less, even more preferably 0.5% or less, and even more preferably 0.2% or less.

[0024] On the other hand, if we want to further reduce the dielectric loss tangent in the high-frequency range of the glass of the present invention, specifically if we want the dielectric loss tangent (tanδ) of the glass of the present invention at 35 GHz to be 0.002 or less, the value of formula (B) is preferably 0% or less, more preferably -0.1% or less, even more preferably -0.2% or less, even more preferably -0.3% or less, especially preferably -0.4% or less, even more preferably -0.5% or less, even more preferably -0.6% or less, even more preferably -0.8% or less, and even more preferably -1% or less.

[0025] In the glass of the present invention, when the total content of formula (C) is represented by [SiO2] + [B2O3], the value of formula (C) is preferably 88% or more and 100% or less, preferably 96% or less, and more preferably 89.4% or more and 93% or less. If the value of formula (C) is 88% or more, the relative permittivity and dielectric loss tangent in the high-frequency range will be low. The value of formula (C) is more preferably 89.5% or higher, even more preferably 90% or higher, even more preferably 90.5% or higher, especially preferably 91% or higher, and even more preferably 91.5% or higher. If the value of formula (C) is 93% or less, the glass viscosity is 10 2 The temperature T2 at which the pressure becomes dPa·s (hereinafter referred to as temperature T2) decreases. The value of formula (C) is preferably 92.5% or less, and more preferably 92% or less.

[0026] In the glass of the present invention, when formula (D) is the ratio of content represented by [Al2O3] / [B2O3], the value of formula (D) is preferably 0.1 or more and 0.3 or less. If the value of formula (D) is within the above range, the acid resistance of the glass is improved. The value of formula (D) is preferably 0.12 or higher, and more preferably 0.13 or higher. The value of formula (D) is preferably 0.28 or less, more preferably 0.26 or less, even more preferably 0.25 or less, even more preferably 0.23 or less, and especially preferably 0.2 or less.

[0027] In the glass of the present invention, when formula (E) is the ratio of content represented by [MgO] / ([MgO]+[CaO]+[SrO]+[BaO]), the value of formula (E) is preferably 0.5 or higher. If the value of formula (E) is within the above range, the phase separation characteristics and acid resistance of the glass are improved. The value of formula (E) is preferably 0.55 or higher, more preferably 0.6 or higher, even more preferably 0.65 or higher, even more preferably 0.7 or higher, especially preferably 0.75 or higher, and still more preferably 0.85 or higher. The upper limit of the value of formula (E) is not particularly limited, but a value of 0.95 or less is preferable because it can suppress the rise in surface devitrification temperature, and a value of 0.9 or less is more preferable.

[0028] In the glass of the present invention, when formula (F) is the ratio of content represented by ([MgO]+[CaO]+[SrO]+[BaO]) / [Al2O3], it is preferable that the value of formula (F) is 0.5 or more and 1.2 or less. If the value of formula (F) is 0.5 or more, the rise in surface devitrification temperature can be suppressed. This improves the quality of the glass and increases productivity when manufacturing glass sheets. The value of formula (F) is preferably 0.55 or higher, more preferably 0.6 or higher, even more preferably 0.65 or higher, even more preferably 0.7 or higher, especially preferably 0.75 or higher, even more preferably 0.8 or higher, even more preferably 0.85 or higher, even more preferably 0.9 or higher, even more preferably 0.95 or higher, even more preferably 1 or higher, and even more preferably 1.05 or higher. If the value of equation (F) is 1.2 or less, the acid resistance and phase separation properties of the glass will improve. The value of equation (F) is more preferably 1.1 or less.

[0029] In the glass of the present invention, when formula (H) is the ratio of content represented by [BaO] / [MgO], the value of formula (H) is preferably 0.01 or more and 3 or less. If the value of formula (H) is 0.01 or greater, the phase separation characteristics of the glass are improved. A value of 0.02 or greater is more preferable, 0.03 or greater is even more preferable, 0.04 or greater is even more preferable, 0.05 or greater is particularly preferable, and 0.06 or greater is even more preferable. If the value of formula (H) is 3 or less, the deterioration of the glass's acid resistance can be suppressed. The value of formula (H) is more preferably 2.5 or less, even more preferably 2 or less, even more preferably 1 or less, especially preferably 0.5 or less, even more preferably 0.3 or less, even more preferably 0.2 or less, even more preferably 0.15 or less, and even more preferably 0.1 or less.

[0030] In the glass of the present invention, when formula (I) is an amount represented by [SiO2]-[B2O3], the value of formula (I) is preferably 20% or more and 40% or less. If the value of formula (I) is 20% or more, the acid resistance of the glass is improved. A value of formula (I) of 22% or more is more preferable, 24% or more is even more preferable, 25% or more is even more preferable, 26% or more is particularly preferable, 27% or more is even more preferable, 28% or more is even more preferable, 29% or more is even more preferable, and 30% or more is even more preferable. If the value of equation (I) is 40% or less, the dielectric loss tangent in the high-frequency region can be reduced. By lowering the dependence of the dielectric loss tangent on cooling, the deterioration of the dielectric loss tangent due to rapid cooling can be suppressed, resulting in superior productivity. The value of formula (I) is more preferably 38% or less, even more preferably 36% or less, even more preferably 35% or less, especially preferably 34% or less, even more preferably 33% or less, and even more preferably 32% or less.

[0031] In the glass of the present invention, when formula (J) is the ratio of content represented by ([SrO]+[BaO]) / ([MgO]+[CaO]), the value of formula (J) is preferably 0.05 or more and 2 or less. If the value of formula (J) is 0.05 or more, while maintaining the phase separation characteristics of the glass, the dielectric tangent in the high-frequency region can be lowered. The value of formula (J) is more preferably 0.1 or more, further preferably 0.15 or more, even more preferably 0.2 or more, still more preferably 0.25 or more, and yet more preferably 0.3 or more. If the value of formula (J) is 2 or less, deterioration of the acid resistance of the glass can be suppressed. The value of formula (J) is more preferably 1.5 or less, further preferably 1 or less, even more preferably 0.8 or less, still more preferably 0.6 or less, yet more preferably 0.5 or less, even more preferably 0.45 or less, still more preferably 0.4 or less, and further more preferably 0.35 or less.

[0032] The glass of the present invention may contain Fe in order to improve the solubility of the glass. However, from the viewpoints of coloring of the glass, reduction of the transmittance in the visible region, relative permittivity in the high-frequency region, and lowering of the dielectric tangent, the content of Fe is preferably 0.5 mol% or less in terms of Fe2O3, more preferably 0.2 mol% or less, and further preferably 0.1 mol% or less. The content of Fe is preferably 0.15% or less, more preferably 0.1% or less, further preferably 0.05% or less, and even more preferably 0.03% or less in terms of mass percentage based on the oxide standard of Fe2O3.

[0033] The glass of the present invention has a β-OH value (mm -1 ) of 0.05 mm -1 or more and 1.0 mm -1 or less is preferable. The β-OH value is an index of the water content in the glass. For a glass sample, the absorbance with respect to light having a wavelength of 2.75 to 2.95 μm is measured, and the maximum value β max of the absorbance is divided by the thickness (mm) of the sample to obtain it. If the β-OH value is 0.05 mm -1 or more, the resistance value at the temperature T2 at which the glass viscosity becomes 10 2 dPa·s becomes low, which is suitable for melting the glass by electric heating, and there are few bubble defects in the glass. Specifically, when the β-OH value is 0.05 mm -1 or more, the solubility is improved. When the β-OH value is 1.0 mm-1 The following conditions can suppress bubble defects in the glass. The β-OH value is 0.8 mm. -1 The following is more preferable: 0.7 mm -1 The following is even more preferable: 0.6 mm -1 The following is even more preferable: The β-OH value is 0.1 mm -1 The above is more preferable, 0.2 mm -1 The above is even more preferable, 0.25 mm -1 The above is even more preferable, 0.3 mm -1 The above is particularly preferable, 0.35 mm -1 The above are particularly preferable.

[0034] The glass of the present invention preferably contains substantially no alkali metal oxides such as Li2O, Na2O, and K2O. In the present invention, "substantially free of alkali metal oxides" means that they are not present except for unavoidable impurities introduced from the raw materials, etc., that is, they are intentionally omitted. However, it is preferable that the glass of the present invention does not contain alkali metal oxides to achieve specific effects, namely, to lower the strain point, lower the glass transition temperature (Tg), lower the annealing point, lower the temperature T2, or lower the glass viscosity to 10 4 Alkali metal oxides may be included in a predetermined amount to obtain effects such as lowering the temperature T4 at which dPa·s occurs (hereinafter referred to as temperature T4). The total alkali metal oxide content is preferably 1% or less, more preferably 0.7% or less, even more preferably 0.6% or less, even more preferably 0.5% or less, especially preferably 0.45% or less, even more preferably 0.4% or less, and even more preferably 0.35% or less. Furthermore, at least one alkali metal oxide selected from the group consisting of Li2O, Na2O, and K2O may be included in a total content of 0.4% or less, expressed as [Li2O]+[Na2O]+[K2O]. If the total content expressed as [Li2O]+[Na2O]+[K2O] is 0.4% or less, the dielectric loss tangent in the high-frequency range will be low, and it will be suitable for use as a substrate for thin-film transistors (TFTs). The amount of [Li2O]+[Na2O]+[K2O] is more preferably 0.35% or less, even more preferably 0.3% or less, even more preferably 0.25% or less, especially preferably 0.2% or less, even more preferably 0.15% or less, even more preferably 0.10% or less, and even more preferably 0.05% or less. The total content of Li2O, Na2O, and K2O is preferably 0.4% or less, more preferably 0.35% or less, even more preferably 0.3% or less, even more preferably 0.25% or less, especially preferably 0.2% or less, even more preferably 0.15% or less, even more preferably 0.10% or less, and even more preferably 0.05% or less, expressed as a mass percentage based on oxides.

[0035] In the glass of the present invention, when formula (G) is the ratio of content represented by [Li2O] / ([Li2O]+[Na2O]+[K2O]), the value of formula (G) is preferably 0.5 or higher. If the value of formula (G) is within the above range, the relative permittivity and dielectric loss tangent in the high-frequency region can be lowered, while the strain point, Tg, annealing point, temperature T2, temperature T4, or the resistance value of the glass can be lowered, thereby improving the productivity of the glass. The value of formula (G) is more preferably 0.55 or higher, even more preferably 0.6 or higher, even more preferably 0.65 or higher, and especially preferably 0.7 or higher. The value of formula (G) is preferably 0.95 or lower.

[0036] To improve the clarity of the glass, the glass of the present invention may contain at least one selected from the group consisting of SnO2, Cl, and SO3 in a total content of 0.5% or less. The total content of these is preferably 0.4% or less, more preferably 0.3% or less, even more preferably 0.2% or less, and still more preferably 0.1% or less. The total content of SnO2, Cl, and SO3 is preferably 0.5% or less, more preferably 0.3% or less, and even more preferably 0.1% or less, expressed as a mass percentage based on oxides. The SnO2 content is preferably 0.5% or less, more preferably 0.4% or less, and even more preferably 0.3% or less. The SnO2 content is preferably 0.3% or less, more preferably 0.2% or less, and even more preferably 0.1% or less, expressed as a mass percentage based on oxides.

[0037] To improve the acid resistance of the glass, the glass of the present invention may contain, as a trace component, at least one selected from the group consisting of Sc2O3, TiO2, ZnO, Ga2O3, GeO2, Y2O3, ZrO2, Nb2O5, In2O3, TeO2, HfO2, Ta2O5, WO3, Bi2O3, La2O3, Gd2O3, Yb2O3, and Lu2O3. However, if the content of trace components is too high, the phase separation properties of the glass tend to deteriorate, so the total content of trace components is preferably 1% or less, more preferably 0.25% or less, even more preferably 0.2% or less, even more preferably 0.1% or less, and especially preferably 0.05% or less. The glass of the present invention may contain only one of the above-mentioned trace components, or it may contain two or more of them.

[0038] To improve the solubility of the glass, the glass of the present invention may contain P2O5. The P2O5 content is preferably 2% or less, more preferably 1% or less, even more preferably 0.5% or less, even more preferably 0.3% or less, and especially preferably 0.1% or less. On the other hand, since P2O5 may volatilize and re-agglomerate in the glass molding equipment and fall onto the glass plate, potentially causing foreign matter defects, it is even more preferably 0.05% or less, even more preferably 0.01% or less, even more preferably 0.005% or less, and most preferably substantially absent. In the present invention, substantially absent P2O5 means that it is not contained except as an unavoidable impurity introduced from the raw materials, that is, it is intentionally omitted.

[0039] For purposes such as improving the solubility of the glass, lowering the strain point of the glass, lowering the Tg, lowering the annealing point, and lowering the dielectric loss tangent, the glass of the present invention may contain fluorine (F). The F content is preferably 0.1 mol% or more, more preferably 0.2 mol% or more, and even more preferably 0.4 mol% or more. However, from the viewpoint of suppressing the deterioration of glass quality due to the volatilization of F, the F content is preferably 1.5 mol% or less, more preferably 1 mol% or less, even more preferably 0.5 mol% or less, and even more preferably 0.1 mol% or less. The F content is preferably 0.01% or more by mass percentage, more preferably 0.03% or more. The upper limit is preferably 0.2% or less, more preferably 0.1% or less, and even more preferably 0.05% or less.

[0040] To improve the solubility, clarity, and moldability of the glass, to obtain absorption at specific wavelengths, and to improve density, hardness, bending rigidity, and durability, the glass of the present invention may contain at least one selected from the group consisting of Se2O3, TeO2, Ga2O3, In2O3, GeO2, CdO, BeO, and Bi2O3. The total content of these is preferably 2% or less, more preferably 1% or less, even more preferably 0.5% or less, even more preferably 0.3% or less, especially preferably 0.1% or less, even more preferably 0.05% or less, and even more preferably 0.01% or less.

[0041] In order to improve the solubility, clarity, and moldability of the glass, and also to improve the hardness of the glass, such as Young's modulus, the glass of the present invention may contain rare earth oxides and transition metal oxides.

[0042] The glass of the present invention may contain at least one rare earth oxide selected from the group consisting of Sc2O3, Y2O3, La2O3, Ce2O3, Pr2O3, Nd2O3, Pm2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3, and Lu2O3. The total content of these is preferably 2% or less, more preferably 1% or less, even more preferably 0.5% or less, even more preferably 0.3% or less, especially preferably 0.1% or less, even more preferably 0.05% or less, and even more preferably 0.01% or less.

[0043] The glass of the present invention may contain at least one transition metal oxide selected from the group consisting of V2O5, Ta2O3, Nb2O5, WO3, MoO3, and HfO2. The total content of these is preferably 2% or less, more preferably 1% or less, even more preferably 0.5% or less, even more preferably 0.3% or less, especially preferably 0.1% or less, even more preferably 0.05% or less, and even more preferably 0.01% or less.

[0044] To improve the solubility of the glass, the glass of the present invention may contain ThO2, an actinide oxide. The ThO2 content is preferably 2% or less, more preferably 1% or less, even more preferably 0.5% or less, even more preferably 0.3% or less, especially preferably 0.1% or less, even more preferably 0.05% or less, even more preferably 0.01% or less, and even more preferably 0.005% or less.

[0045] The dielectric loss tangent (tanδ) of the glass of the present invention at 35 GHz is preferably 0.005 or less. If the dielectric loss tangent at 35 GHz is 0.005 or less, dielectric loss in the high-frequency region exceeding 30 GHz can be reduced. The dielectric loss tangent at 35 GHz is more preferably 0.004 or less, even more preferably 0.003 or less, even more preferably 0.002 or less, and especially preferably 0.0015 or less. There is no particular lower limit, but for example, 0.0005 or more is preferred. Furthermore, the dielectric loss tangent at 10 GHz is preferably 0.003 or less, more preferably 0.0025 or less, even more preferably 0.002 or less, and even more preferably 0.0015 or less. The lower limit is not particularly limited, but for example, 0.0005 or more is preferred.

[0046] The relative permittivity of the glass of the present invention at 35 GHz is preferably 5 or less. If the relative permittivity at 35 GHz is 5 or less, dielectric loss in the high-frequency range can be reduced. The relative permittivity at 35 GHz is more preferably 4.8 or less, even more preferably 4.6 or less, even more preferably 4.5 or less, and especially preferably 4.3 or less. The lower limit is not particularly limited, but for example, 3 or more is preferred. Furthermore, the relative permittivity at 10 GHz is preferably 5 or less, more preferably 4.8 or less, even more preferably 4.6 or less, even more preferably 4.4 or less, and especially preferably 4.3 or less. The lower limit is not particularly limited, but for example, 3 or more is preferred.

[0047] In the present invention, when the glass transition temperature is Tg°C, and the glass is heated to (Tg+50)°C and then cooled to (Tg-150)°C at a rate of 10°C / min, the dielectric loss tangent at 10 GHz is tanδ10, and similarly the glass is heated to (Tg+50)°C and then cooled to (Tg-150)°C at a rate of 100°C / min, the dielectric loss tangent at 10 GHz is tanδ100, it is preferable that -0.0003 ≤ (tanδ100 - tanδ10) ≤ 0.0003. Satisfying this relationship makes it possible to suppress the deterioration of the dielectric loss tangent tanδ even when rapidly cooling is performed during glass manufacturing.

[0048] For glass compositions where tanδ100-tanδ10 satisfies the above range, it is preferable that the value of formula (C), which is the total content represented by [SiO2]+[B2O3] as described above, is 88% or more and 96% or less. When the value of formula (C) is 88% or more, deterioration of the dielectric loss tangent tanδ can be suppressed even if the cooling rate is fast during glass production. The value of formula (C) is more preferably 89% or more, even more preferably 89.5% or more, even more preferably 90% or more, especially preferably 90.5% or more, even more preferably 91% or more, and even more preferably 91.5% or more. Furthermore, when the value of formula (C) exceeds 96%, the influence of the dielectric loss tangent tanδ on the cooling rate is small, but the glass melting temperature becomes high, which may lead to the need to produce glass using methods such as vapor phase synthesis, potentially resulting in lower glass productivity. Furthermore, since there is no room to include oxides that improve phase separation characteristics and acid resistance, such as alkaline earth metals and Al2O3, the value of formula (C) is more preferably 95% or less, even more preferably 94.5% or less, even more preferably 94% or less, especially preferably 93.5% or less, even more preferably 93% or less, and even more preferably 92.5% or less.

[0049] Furthermore, for glass compositions where tanδ100-tanδ10 satisfies the above range, a B2O3 content of 18% or more and 35% or less is preferred. A B2O3 content of 18% or more is preferred because it reduces the influence of the dielectric loss tangent tanδ on the cooling rate, resulting in glass with a lower dielectric loss tangent tanδ. A B2O3 content of 19% or more is more preferred, 20% or more is even more preferred, 21% or more is even more preferred, 22% or more is particularly preferred, 23% or more is even more preferred, 24% or more is even more preferred, 25% or more is even more preferred, 26% or more is even more preferred, 27% or more is even more preferred, 28% or more is particularly even more preferred, 28.5% or more is even more preferred, 29% or more is especially preferred, and 29.5% or more is most preferred. Moreover, if the B2O3 content exceeds 35%, phase separation becomes more likely, making it difficult to obtain uniform and transparent glass. In addition, acid resistance and alkali resistance may deteriorate. The B2O3 content is more preferably 34% or less, even more preferably 33% or less, even more preferably 32% or less, especially preferably 31.5% or less, even more preferably 31% or less, and particularly preferably 30.5% or less.

[0050] Furthermore, it is preferable that the glass of the present invention satisfies -0.0003 ≤ (tanδ100 - tanδA) ≤ 0.0003 when the glass is heated to (Tg + 50)°C and then cooled to (Tg - 150)°C at a rate of 100°C / min, with the dielectric loss tangent at 10 GHz being tanδA and the glass transition temperature being Tg°C, and the dielectric loss tangent at 10 GHz being tanδ100.

[0051] For tanδ100-tanδA to satisfy the above range, the glass composition must satisfy the above range for tanδ100-tanδ10, and the cooling rate and time must be adjusted when the glass is cooled from (Tg+50)°C to (Tg-150)°C. During this time, any temperature history is possible, but it is preferable that the equivalent cooling rate A based on the glass's tanδ, as described later, is between 0.01°C / min and 1000°C / min. If the equivalent cooling rate A based on tanδ is lower than 0.01°C / min, the glass will take an enormous amount of time to produce, resulting in poor productivity. The equivalent cooling rate A based on tanδ is more preferably 0.1°C / min or more, even more preferably 1°C / min or more, even more preferably 2°C / min or more, especially preferably 5°C / min or more, even more preferably 10°C / min or more, even more preferably 20°C / min or more, even more preferably 30°C / min or more, even more preferably 40°C / min or more, even more preferably 50°C / min or more, especially even more preferably 60°C / min or more, even more preferably 70°C / min or more, particularly preferably 80°C / min or more, and most preferably 90°C / min or more. Furthermore, if the equivalent cooling rate A based on tanδ is greater than 1000°C / min, tanδ100-tanδA becomes too small, i.e., the dielectric loss tangent tanδA deteriorates, which is undesirable. The equivalent cooling rate A based on tanδ is more preferably 900°C / min or less, even more preferably 800°C / min or less, even more preferably 700°C / min or less, especially preferably 600°C / min or less, even more preferably 500°C / min or less, even more preferably 400°C / min or less, even more preferably 350°C / min or less, even more preferably 300°C / min or less, especially more preferably 250°C / min or less, and particularly preferably 200°C / min or less.

[0052] Equivalent cooling rate A based on tanδ: Multiple glass samples are prepared by heating a glass plate to (Tg+50)°C and then cooling it to (Tg-150)°C at a constant cooling rate of X°C / min. The dielectric loss tangent tanδ at 10 GHz is measured. Linear regression is performed so that Log(tanδ) = a × Log(X) + b (where a and b are constants). As an example of a cooling rate of X°C / min, three levels may be used: 1°C / min, 40°C / min, and 200°C / min. For glass produced under any given cooling history, the equivalent cooling rate A is calculated inversely from tanδ using the above regression equation.

[0053] The density of the glass of this invention is 2.58 g / cm³. 3 The following is preferable. This reduces self-weight deflection, making it easier to handle large substrates. It also allows for weight reduction of devices using glass. The density is 2.57 g / cm³. 3 The following is more preferable: 2.56 g / cm³ 3 The following is even more preferable. The lower limit is not particularly limited, but for example, 2 g / cm³ 3 The above is preferable. A large circuit board is, for example, a circuit board with at least one side measuring 1000 mm or more.

[0054] The alkali-free glass of the present invention preferably has a temperature T2 of 1900°C or lower. When T2 is 1900°C or lower, the glass melting properties are excellent, and the burden on manufacturing equipment can be reduced. For example, the lifespan of equipment such as glass melting furnaces can be extended, and productivity can be improved. Furthermore, defects originating from the furnace, such as pitting and Zr defects, can be reduced. T2 is more preferably 1850°C or lower, even more preferably 1800°C or lower, even more preferably 1755°C or lower, especially preferably 1750°C or lower, and still most preferably 1745°C or lower. The lower limit of the temperature T2 is not particularly limited, but for example, 1500°C or higher is preferred.

[0055] The glass temperature T4 of the present invention is preferably 1290°C or lower. When the temperature T4 is 1290°C or lower, the glass exhibits excellent formability. Furthermore, for example, by lowering the temperature during glass molding, volatile substances in the atmosphere surrounding the glass can be reduced, thereby reducing defects in the glass. Since glass can be molded at a lower temperature, the burden on manufacturing equipment can be reduced. For example, the lifespan of equipment such as the float bath used for glass molding can be extended, and productivity can be improved. A temperature T4 of 1280°C or lower is more preferable. The lower limit of temperature T4 is not particularly limited, but for example, 1050°C or higher is preferred.

[0056] Temperatures T2 and T4 were determined by measuring the viscosity using a rotational viscometer according to the method specified in ASTM C 965-96 (2017), and 10 2 dPa·s or 10 4 The temperature at which the temperature becomes dPa·s can be determined. In the embodiments described later, NBS710 and NIST717a were used as reference samples for instrument calibration.

[0057] The Tg of the glass of the present invention is preferably 700°C or lower. If the Tg is 700°C or lower, it is not necessary to raise the temperature of the annealing device, and the reduction in the lifespan of the annealing device can be suppressed. A Tg of 680°C or lower is more preferable, and 670°C or lower is even more preferable. The lower limit of the temperature Tg is not particularly limited, but for example, 450°C or higher is preferred.

[0058] The annealing point of the glass of the present invention is preferably 700°C or lower. If the annealing point is 700°C or lower, it is not necessary to raise the temperature of the annealing device, and the reduction in the lifespan of the annealing device can be suppressed. The annealing point is more preferably 680°C or lower, and even more preferably 670°C or lower. The lower limit of the slow cooling point is not particularly limited, but for example, 450°C or higher is preferred.

[0059] The surface devitrification temperature of the glass of the present invention is preferably 1400°C or lower. A surface devitrification temperature of 1400°C or lower results in excellent formability of the glass. It also suppresses the formation of crystals inside the glass during molding, which can reduce transmittance. Furthermore, it reduces the burden on manufacturing equipment. For example, it can extend the lifespan of equipment such as the float bath used to mold the glass, thereby improving productivity. The surface devitrification temperature is more preferably 1280°C or lower, even more preferably 1260°C or lower, even more preferably 1255°C or lower, especially preferably 1250°C or lower, even more preferably 1245°C or lower, and even more preferably 1240°C or lower. The lower limit of the surface devitrification temperature is not particularly limited, but for example, 900°C or higher is preferred. The surface devitrification temperature in this invention can be determined as follows: Crushed glass particles are placed in a platinum dish and heat-treated for 17 hours in an electric furnace controlled to a constant temperature. After the heat treatment, the highest temperature at which crystals precipitate on the glass surface and the lowest temperature at which crystals do not precipitate are observed using an optical microscope, and the average value of these is defined as the surface devitrification temperature.

[0060] The average thermal expansion coefficient of the glass of the present invention at 50 to 350°C is 20 × 10 -7 A temperature of 20 × 10⁻⁶ or higher is preferred. The average coefficient of thermal expansion at 50 to 350°C is 20 × 10⁻⁶. -7 If the temperature is above / ℃, it is possible to suppress cracking caused by excessively large differences in expansion rates between the glass substrate and the metal film formed on the glass substrate. The average coefficient of thermal expansion at 50-350°C is 25 × 10⁻⁶ -7 A temperature of / ℃ or higher is more preferable. On the other hand, the average coefficient of thermal expansion at 50-350°C is 50 × 10 -7 A temperature of 50 × 10⁻⁶ or less is preferred. The average coefficient of thermal expansion at 50 to 350°C is 50 × 10⁻⁶. -7 If the temperature is below / ℃, it is possible to suppress glass breakage during the manufacturing process of products such as high-frequency devices. The average coefficient of thermal expansion at 50-350°C is 40 × 10⁻⁶ -7 / ℃ or lower is more preferable, 35 × 10 -7 More preferably below / ℃, 32 × 10 -7A temperature of / ℃ or lower is even more preferable.

[0061] The Young's modulus of the glass of the present invention is preferably 40 GPa or higher. If the Young's modulus is within the above range, it is possible to suppress problems such as warping, bending, or cracking of the glass substrate after the deposition of a metal film, such as a Cu film, which is carried out in the manufacturing process of high-frequency devices. A Young's modulus of 43 GPa or higher is more preferable, 45 GPa or higher is even more preferable, and 47 GPa or higher is even more preferable. There is no particular upper limit to the Young's modulus, but for example, 70 GPa or less is preferred.

[0062] The specific modulus of the glass of this invention is 20 GPa·cm. 3 A value of 21 GPa·cm is preferable. If the specific modulus is within the above range, the amount of glass deflection can be suppressed. The specific modulus is 21 GPa·cm. 3 More preferably 22 GPa·cm² or more. 3 A value of 1 / g or more is even more preferable. There is no particular upper limit to the specific modulus, but for example, 35 GPa·cm 3 Preferably less than / g

[0063] The glass of the present invention exhibits a glass component elution rate of 0.02 mg / cm² per unit surface area when immersed for 170 seconds in an aqueous solution at 45°C containing 6% by mass of HNO3 and 5% by mass of H2SO4. 2 The following is preferable. If the amount of glass component elution is within the above range, acid resistance is good. The amount of glass component elution is 0.015 mg / cm³. 2 The following are preferable. There is no particular lower limit to the amount of glass components leached out, but for example, 0.0001 mg / cm³ 2 The above is preferable.

[0064] When the glass of the present invention is used as a glass plate with a thickness of 1 mmt, the haze value of the glass plate is preferably 0.5% or less. If the haze value is within the above range, the phase separation characteristics of the glass are excellent, and for example, when the glass substrate is acid-cleaned, localized irregularities on the substrate surface can be effectively prevented. This reduces the transmission loss of high-frequency signals. A haze value of 0.4% or less is more preferable, 0.3% or less is even more preferable, 0.2% or less is even more preferable, and 0.1% or less is particularly preferable. The lower limit of the haze value is not particularly limited, but for example, 0.01% or higher is preferred.

[0065] The glass plate containing the glass of the present invention (hereinafter referred to as "the glass plate of the present invention") is suitable for applications such as glass substrates for high-frequency devices, panel antennas, window glass, vehicle window glass, and touch panel cover glass, due to the above-mentioned features.

[0066] Figure 1 is a cross-sectional view showing an example of the configuration of a circuit board for high-frequency devices. The circuit board 1 shown in Figure 1 comprises an insulating glass substrate 2, a first wiring layer 3 formed on the first main surface 2a of the glass substrate 2, and a second wiring layer 4 formed on the second main surface 2b of the glass substrate 2. The first and second wiring layers 3 and 4 form a microstrip line as an example of a transmission line. The first wiring layer 3 constitutes a signal line, and the second wiring layer 4 constitutes a ground line. However, the structure of the first and second wiring layers 3 and 4 is not limited to this. Furthermore, the wiring layers may be formed on only one of the main surfaces of the glass substrate 2.

[0067] The first and second wiring layers 3 and 4 are layers formed of a conductor, and their thickness is typically around 0.1 to 50 μm. The conductors forming the first and second wiring layers 3 and 4 are not particularly limited, and for example, metals such as copper, gold, silver, aluminum, titanium, chromium, molybdenum, tungsten, platinum, and nickel, or alloys and metal compounds containing at least one of these metals can be used. The structure of the first and second wiring layers 3 and 4 is not limited to a single-layer structure, but may have a multi-layer structure, such as a laminated structure of a titanium layer and a copper layer. The method for forming the first and second wiring layers 3 and 4 is not particularly limited, and for example, various known formation methods such as printing using a conductor paste, dipping, plating, vapor deposition, and sputtering can be applied.

[0068] When the glass plate of the present invention is used as the glass substrate 2, it is preferable that the dielectric loss tangent (tanδ) of the glass substrate 2 at 35 GHz is 0.005 or less. If the dielectric loss tangent of the glass substrate 2 at 35 GHz is 0.005 or less, dielectric loss in the high-frequency region exceeding 30 GHz can be reduced. The dielectric loss tangent of the glass substrate 2 at 35 GHz is more preferably 0.004 or less, even more preferably 0.003 or less, even more preferably 0.0025 or less, especially preferably 0.002 or less, and still more preferably 0.0015 or less. A relative permittivity of 5 or less at 35 GHz is preferable because it reduces dielectric loss in the high-frequency range. A relative permittivity of 4.8 or less at 35 GHz is more preferable, 4.7 or less is even more preferable, 4.6 or less is even more preferable, 4.5 or less is particularly preferable, 4.3 or less is even more preferable, 4.1 or less is even more preferable, 4 or less is even more preferable, and 3.8 or less is even more preferable.

[0069] Furthermore, the glass substrate 2 has main surfaces 2a and 2b and an end face. At least one of the main surfaces 2a and 2b on which the first and second wiring layers 3 and 4 are formed on the glass substrate 2 preferably has an arithmetic mean roughness Ra of 1.5 nm or less, and more preferably both main surfaces have an arithmetic mean roughness Ra of 1.5 nm or less. If the arithmetic mean roughness Ra of the main surfaces is within the above range, even if the skin effect occurs on the first and second wiring layers 3 and 4 in a high-frequency region exceeding 30 GHz, the skin resistance of the first and second wiring layers 3 and 4 can be reduced, thereby reducing conductor loss. The arithmetic mean roughness Ra of the main surfaces 2a and 2b of the glass substrate 2 is more preferably 1 nm or less, and even more preferably 0.5 nm or less. The main surface of the glass substrate 2 refers to the surface on which the wiring layer is formed. If the wiring layer is formed on one of the main surfaces, it is sufficient that the arithmetic mean roughness Ra of that one main surface satisfies the condition of 1.5 nm or less. In this specification, the arithmetic mean roughness Ra refers to the value in accordance with JIS B0601 (2001).

[0070] The surface roughness of the main surfaces 2a and 2b of the glass substrate 2 can be achieved as needed by polishing the surface of the glass substrate 2. For polishing the surface of the glass substrate 2, for example, polishing using an abrasive mainly composed of cerium oxide or colloidal silica and a polishing pad; polishing using a polishing slurry containing an abrasive and an acidic or alkaline dispersion medium and a polishing pad; or polishing using an acidic or alkaline etching solution. These polishing treatments are applied according to the surface roughness of the raw material of the glass substrate 2, and for example, pre-polishing and finish polishing may be applied in combination. In addition, it is preferable to chamfer the edges of the glass substrate 2 to prevent cracking, chipping, or breakage of the glass substrate 2 caused by the edges during process flow. The chamfering can be any of the following: C-chamfering, R-chamfering, thread chamfering, etc.

[0071] The use of such a glass substrate 2 can reduce the transmission loss of the circuit board 1 at 35 GHz. For example, it can be reduced to 1 dB / cm or less. Therefore, the characteristics such as quality and intensity of high-frequency signals, especially high-frequency signals exceeding 30 GHz, and even higher high-frequency signals exceeding 35 GHz, are maintained, making it possible to provide a glass substrate 2 and circuit board 1 suitable for high-frequency devices that handle such high-frequency signals. In other words, the characteristics and quality of high-frequency devices that handle such high-frequency signals can be improved. The transmission loss of the circuit board 1 at 35 GHz is preferably 0.5 dB / cm or less.

[0072] The shape of the glass plate of the present invention is not particularly limited, but a thickness of 0.7 mm or less is preferred. When the glass plate thickness is 0.7 mm or less, it can be used as a glass substrate for high-frequency devices to make high-frequency devices thinner, smaller, and improve production efficiency. In addition, the ultraviolet transmittance is improved, and manufacturability can be enhanced by using ultraviolet curing materials in the device manufacturing process. The thickness of the glass plate is more preferably 0.6 mm or less, even more preferably 0.5 mm or less, even more preferably 0.4 mm or less, especially preferably 0.3 mm or less, still even more preferably 0.2 mm or less, and most preferably 0.1 mm or less. The lower limit is about 0.01 mm.

[0073] When the glass plate is used as a large substrate, it is preferable that at least one side is 1000 mm or longer, more preferably 1500 mm or longer, and even more preferably 1800 mm or longer. There is no particular upper limit, but the size of one side is usually 4000 mm or less. The glass plate is also preferably rectangular.

[0074] Next, the method for manufacturing a glass plate according to the present invention will be described. When manufacturing a glass plate, the process involves a melting step in which glass raw materials are heated to obtain molten glass, a clarification step in which bubbles are removed from the molten glass, a molding step in which the molten glass is formed into a plate shape to obtain a glass ribbon, and a slow cooling step in which the glass ribbon is slowly cooled to room temperature. Alternatively, a method may be used in which the molten glass is formed into a block shape, slowly cooled, and then cut and polished to produce a glass plate.

[0075] The melting process involves preparing the raw materials to achieve the target glass composition, continuously feeding the raw materials into a melting furnace, and heating them to a temperature of preferably 1450 to 1750°C to obtain molten glass. In this embodiment, the alkali-free glass has a low resistance value in the temperature range where the glass raw materials melt, for example, around 1500°C. Therefore, it is preferable to use an electric melting furnace and melt the glass by electric heating. However, electric heating and heating with a burner may be used in combination.

[0076] The raw materials can also include halides such as oxides, carbonates, nitrates, hydroxides, and chlorides. In processes where molten glass comes into contact with platinum during dissolution or clarification, minute platinum particles may dissolve into the molten glass and become foreign matter in the resulting glass plate. However, using nitrate raw materials is effective in preventing the formation of platinum foreign matter.

[0077] As nitrates, strontium nitrate, barium nitrate, magnesium nitrate, calcium nitrate, etc. can be used. The use of strontium nitrate is more preferable. The particle size of the raw materials can be used as appropriate, from large particles of several hundred μm that do not leave any undissolved residue, to small particles of several μm that do not scatter during raw material transport and do not aggregate as secondary particles. Granulated materials can also be used. The water content of the raw materials can be adjusted as appropriate to prevent scattering of the raw materials. β-OH value, redox degree of Fe (redox [Fe 2+ / ( Fe 2+ +Fe 3+ The dissolution conditions for )) can also be adjusted as appropriate.

[0078] The next clarification step is to remove bubbles from the molten glass obtained in the dissolution step described above. For the clarification step, a defoaming method by reduced pressure may be applied, or defoaming may be performed by raising the temperature above the dissolution temperature of the raw materials. SO3 or SnO2 can also be used as a clarifying agent. As an SO3 source, sulfates of at least one element selected from Al, Na, K, Mg, Ca, Sr, and Ba are preferred, and sulfates of alkaline earth metals are more preferred, with CaSO4·2H2O, SrSO4, and BaSO4 being particularly preferred because they have a significant effect in increasing the size of bubbles.

[0079] In the defoaming method by reduced pressure, the use of halogens such as Cl or F is preferred as a clarifying agent. As a Cl source, chlorides of at least one element selected from Al, Mg, Ca, Sr, and Ba are preferred, alkaline earth metal chlorides are more preferred, and among these, SrCl2·6H2O and BaCl2·2H2O are even more preferred because they significantly increase foam volume and have low deliquescence. As a F source, fluorides of at least one element selected from Al, Na, K, Mg, Ca, Sr, and Ba are preferred, alkaline earth metal fluorides are more preferred, and among these, CaF2 is even more preferred because it significantly increases the solubility of the glass raw material.

[0080] Tin compounds, such as SnO2, generate O2 gas in molten glass. In molten glass, at temperatures of 1450°C or higher, SnO2 is reduced to SnO, generating O2 gas and promoting the growth of large bubbles. During the manufacture of glass plates, the glass raw materials are heated to approximately 1450-1750°C to melt, which allows the bubbles in the molten glass to grow more effectively. When using SnO2 as a clarifying agent, it is preferable to prepare the raw materials so that they contain 0.01% or more of the tin compound in terms of SnO2, relative to 100% of the total amount of the base composition. A SnO2 content of 0.01% or more is preferable because it provides a clarifying effect during the melting of the glass raw materials. A SnO2 content of 0.05% or more is more preferable, and 0.1% or more is even more preferable. A SnO2 content of 0.3% or less is preferable because it suppresses the occurrence of glass discoloration and devitrification. The tin compound content in the glass is more preferably 0.25% or less, even more preferably 0.2% or less, and even more preferably 0.15% or less, based on SnO2 equivalent relative to 100% of the total amount of the glass matrix composition.

[0081] The next molding step is to form the molten glass, from which bubbles have been removed in the clarification step described above, into a plate shape to obtain a glass ribbon. As for the molding step, known methods for forming glass into a plate shape can be applied, such as the float method, in which molten glass is poured onto a molten metal such as tin to form a plate shape and obtain a glass ribbon; the overflow downdraw method (fusion method), in which molten glass is poured downwards from a trough-shaped member; and the slit downdraw method, in which molten glass is poured down through a slit. Among these, the float method or the fusion method are preferred from the viewpoint of no polishing or light polishing.

[0082] Next, the annealing process involves cooling the glass ribbon obtained in the molding process down to room temperature under controlled cooling conditions. The annealing process involves cooling the glass ribbon to form a glass ribbon, and then further annealing it down to room temperature under predetermined conditions. After cutting the annealed glass ribbon, a glass plate is obtained.

[0083] If the cooling rate R in the slow cooling process is too high, distortion is likely to remain in the glass after cooling. Also, the equivalent cooling rate, which is a parameter that reflects the virtual temperature, becomes too high, and as a result, glass shrinkage cannot be reduced. For this reason, it is preferable to set R so that the equivalent cooling rate is 800°C / min or less. More preferably, the equivalent cooling rate is 400°C / min or less, even more preferably 100°C / min or less, and even more preferably 50°C / min or less. On the other hand, if the cooling rate is too low, the process time becomes too long, resulting in low productivity. For this reason, it is preferable to set it to 0.1°C / min or more, more preferably 0.5°C / min or more, and even more preferably 1°C / min or more. The equivalent cooling rate, which is a parameter that reflects the virtual temperature, is preferably based on the refractive index for ease of evaluation, but the equivalent cooling rate based on tanδ may also be used as an indicator.

[0084] Here, the definition and evaluation method of the equivalent cooling rate based on the refractive index are as follows: A glass sample is prepared by processing a glass of the target composition into a rectangular parallelepiped measuring 10 mm × 10 mm × 0.3 to 2.0 mm. The glass sample is heated in an infrared electric furnace and held at the strain point + 170°C for 5 minutes, after which the glass sample is cooled to room temperature (25°C). At this time, multiple glass samples are prepared by changing the cooling rate in the range of 1°C / min to 1000°C / min.

[0085] Using a precision refractive index measuring device (e.g., Shimadzu Devices KPR2000), the d-line (wavelength 587.6 nm) refractive index n of multiple glass samples is measured. d Measure the n. The V-block method or the minimum angle method may be used for measurement. d By plotting n against the logarithm of the cooling rate, we can see the relationship between the above cooling rate and n d Obtain a calibration curve.

[0086] Next, n of glass of the same composition that was actually manufactured through processes such as melting, molding, and cooling. d The obtained n is measured by the measurement method described above. d The corresponding cooling rate (referred to as the equivalent cooling rate in this embodiment) is determined from the calibration curve described above.

[0087] The method for manufacturing the glass plate of the present invention is not limited to the above. For example, when manufacturing the glass plate of the present invention, the glass may be formed into a plate by a press molding method in which molten glass is directly formed into a plate.

[0088] Furthermore, when manufacturing the glass plate of the present invention, in addition to the manufacturing method using a melting tank made of refractory material, a crucible made of platinum or an alloy mainly composed of platinum (hereinafter referred to as a platinum crucible) may be used in the melting tank or clarification tank. When a platinum crucible is used, the melting process involves preparing the raw materials to achieve the composition of the glass plate to be obtained, heating the platinum crucible containing the raw materials in an electric furnace, preferably to about 1450 to 1700°C, inserting a platinum stirrer, and stirring for 1 to 3 hours to obtain molten glass.

[0089] In the molding process of manufacturing glass plates using a platinum crucible, molten glass is poured onto, for example, a carbon plate or into a mold to form a plate or block. The annealing process typically involves holding the glass at a temperature of approximately Tg + 50°C, then cooling it at a rate of approximately 1-10°C / min to near the strain point, and then cooling it to room temperature at a rate that does not leave any residual strain. After cutting and polishing to the desired shape, a glass plate is obtained. Alternatively, the cut glass plate may be heated to, for example, approximately Tg + 50°C, and then slowly cooled to room temperature at a predetermined cooling rate. In this way, the equivalent cooling rate of the glass can be adjusted.

[0090] The circuit board 1 using the glass plate of the present invention as the glass substrate 2 is suitable for high-frequency devices that handle high-frequency signals, particularly high-frequency signals exceeding 30 GHz, and even high-frequency signals exceeding 35 GHz, and can reduce the transmission loss of such high-frequency signals and improve characteristics such as the quality and strength of the high-frequency signals. The circuit board 1 using the glass plate of the present invention as the glass substrate 2 is suitable for high-frequency devices (electronic devices) such as semiconductor devices used in communication equipment such as mobile phones, smartphones, personal digital assistants, and Wi-Fi devices, as well as surface acoustic wave (SAW) devices, radar components such as radar transceivers, and antenna components such as liquid crystal antennas and panel antennas. In other words, the present invention relates not only to a glass substrate for high-frequency devices containing the glass of the present invention, but also to a panel-type antenna containing the glass of the present invention.

[0091] Furthermore, the glass of the present invention can be suitably applied to other products for the purpose of reducing transmission loss of high-frequency signals. In other words, the present invention also relates to window glass, vehicle window glass, and touch panel cover glass, which include the glass of the present invention. The glass plate containing the glass of the present invention can stably transmit and receive radio waves in the high frequency band and is resistant to damage and breakage, making it suitable for window glass, vehicle windows, and touch panel cover glass. For vehicle windows, for example, windows for autonomous vehicles are more preferable. [Examples]

[0092] Examples will be described below, but the present invention is not limited to these examples. In the following, Examples 1-14, 16, 29-37, 39-46, and 50-64 are examples, and Examples 17-28 and 47-49 are comparative examples.

[0093] Glass plates were prepared with the compositions shown in Tables 1-11 (expressed in molar percentages based on oxides), a thickness of 1.0 mm, a shape of 50 × 50 mm, and an arithmetic mean surface roughness Ra of 1.0 nm. The glass plates were prepared by a melting method using a platinum crucible. Raw materials such as silica sand were mixed to obtain glass with the compositions shown in Tables 1-11, and 1 kg batches were prepared. The raw materials were placed in a platinum crucible and heated in an electric furnace at a temperature of 1650°C for 3 hours to melt the glass. During melting, a platinum stirrer was inserted into the platinum crucible and stirred for 1 hour to homogenize the glass. The molten glass was poured onto a carbon plate and formed into a plate shape. The plate-shaped glass was then placed in an electric furnace at a temperature of approximately Tg + 50°C and held for 1 hour. The electric furnace was cooled to Tg - 100°C at a cooling rate of 1°C / min, and then the glass was allowed to cool to room temperature. Subsequently, the glass was cut and polished to form a plate, thereby obtaining a glass sheet.

[0094] Tables 1-6 and 9-11 show the average thermal expansion coefficient, density, Tg, Young's modulus, specific modulus, temperature T2, temperature T4, relative permittivity at 10 GHz or 35 GHz, dielectric loss tangent at 10 GHz or 35 GHz, tanδ100-tanδ10, surface devitrification temperature, and, as an evaluation of acid resistance, the amount of glass components eluted per unit surface area (6%HNO3+5%H2SO4@45℃×170sec) when immersed for 170 seconds in a 45℃ aqueous solution containing 6% by mass of HNO3 and 5% by mass of H2SO4, haze evaluation, and β-OH values ​​for the glass plates of Examples 1-14, 16-37, 39-40, and 50-64. The haze evaluation is an indicator of the phase separation characteristics of the glass. Values ​​in parentheses in the tables are calculated or estimated values, and blank spaces indicate that the values ​​were not measured. For the glass plates of Examples 41-49, the β-OH value, equivalent cooling rate based on tanδ, tanδA, and tanδ100-tanδA are shown in Tables 7 and 8.

[0095] The measurement methods for each physical property are shown below.

[0096] (Average thermal expansion coefficient) Measurements were taken using a differential thermal expander in accordance with the method specified in JIS R3102 (1995). The measurement temperature range was 50 to 350°C, and the unit was ×10⁻⁶. -7 It was expressed as / ℃.

[0097] (density) The density of a 20g glass mass, free of bubbles, was measured using the Archimedes method.

[0098] (Tg) The measurement was performed using the thermal expansion method in accordance with the method specified in JIS R3103-3 (2001).

[0099] (Young's modulus) Measurements were taken using the ultrasonic pulse method on glass with a thickness of 0.5 to 10 mm, in accordance with the method specified in JIS Z2280 (1993). The unit is expressed as GPa.

[0100] (Specific modulus of elasticity) The specific modulus (GPa·cm²) obtained by dividing the Young's modulus measured by the method described above by the density also measured by the same method is obtained by dividing the Young's modulus by the density. 3 The value per gram ( / g) was calculated.

[0101] (Temperature T2) The viscosity was measured using a rotational viscometer according to the method specified in ASTM C 965-96, and 10 2 The temperature T2 (°C) at which the pressure was dPa·s was measured.

[0102] (Temperature T4) The viscosity was measured using a rotational viscometer according to the method specified in ASTM C 965-96, and 10 4 The temperature T4 (°C) at which the pressure was dPa·s was measured.

[0103] (Relative permittivity, dielectric loss tangent) Measurements were performed using a cavity resonator and a vector network analyzer, in accordance with the method specified in JIS R1641 (2007). The measurement frequency was 10 GHz or 35 GHz, which are the resonant frequencies of the air in the cavity resonator.

[0104] (tanδ100-tanδ10) The glass plate is placed in an electric furnace and heated to (Tg+50)°C, held for 1 hour, then cooled to (Tg-150)°C at a cooling rate of 10°C / min. The dielectric loss tangent at 10 GHz is then measured and defined as tanδ10. Furthermore, the glass plate is placed in an electric furnace and heated to (Tg+50)°C, held for 1 hour, then cooled to (Tg-150)°C at a cooling rate of 100°C / min. The dielectric loss tangent at 10 GHz is then measured and defined as tanδ100. The difference between the two is calculated as tanδ100 - tanδ10.

[0105] (Surface devitrification temperature) The glass was crushed and classified using a test sieve to obtain particles in the range of 2-4 mm. The resulting glass cullet was ultrasonically cleaned in isopropyl alcohol for 5 minutes, washed with deionized water, dried, placed in a platinum dish, and heat-treated in an electric furnace controlled to a constant temperature for 17 hours. The heat treatment temperature was set in 10°C increments. After heat treatment, the glass was removed from the platinum dish, and the highest temperature at which crystals precipitated on the glass surface and the lowest temperature at which crystals did not precipitate were observed using an optical microscope. The highest temperature at which crystals precipitate on the glass surface and the lowest temperature at which crystals do not precipitate were each measured once. In cases where it is difficult to determine crystal precipitation, measurements may be taken twice. The average value was calculated using the highest temperature at which crystals precipitated on the glass surface and the lowest temperature at which crystals did not precipitate, and this value was defined as the surface devitrification temperature.

[0106] (Acid resistance, 6%HNO3+5%H2SO4@45℃×170sec) The glass sample was immersed in an acidic aqueous solution (6% by mass HNO3 + 5% by mass H2SO4, 45°C) for 170 seconds, and the amount of glass components eluted per unit surface area (mg / cm³) was measured. 2 The following was evaluated: The amount of glass components eluted was 0.02 mg / cm³. 2 The following conditions indicate good acid resistance.

[0107] (Hayes's rating) The haze value of glass was measured using a haze meter (manufacturer: Suga Test Instruments Co., Ltd., model: HZ-V3 Hazemeter). The haze value was measured on a glass plate with a thickness of 1 mm and both sides polished to a mirror finish. The measured values ​​were evaluated according to the following criteria. A: 0.5% or less (transparent is fine) B: More than 0.5% and less than 1% (slightly phase separated (slightly cloudy)) C: Over 1% (clearly shows phase separation (cloudiness))

[0108] (β-OH value) The absorbance of the glass sample was measured for light with wavelengths of 2.75 to 2.95 μm, and the maximum absorbance value β was determined. max The β-OH value was determined by dividing the value by the thickness (mm) of the sample.

[0109] [Table 1]

[0110] In the table, equations (A) to (J) mean the following, respectively. Formula (A): [MgO]+[CaO]+[SrO]+[BaO] Formula (B): [Al2O3]-([MgO]+[CaO]+[SrO]+[BaO]) Formula (C):[SiO2]+[B2O3] Formula (D): [Al2O3] / [B2O3] Formula (E): [MgO] / ([MgO]+[CaO]+[SrO]+[BaO]) Formula (F):([MgO]+[CaO]+[SrO]+[BaO]) / [Al2O3] Formula (G):[Li2O] / ([Li2O]+[Na2O]+[K2O]) Formula (H):[BaO] / [MgO] Formula (I): [SiO2]-[B2O3] Formula (J): ([SrO]+[BaO]) / ([MgO]+[CaO])

[0111] Table 2

[0112] Table 3

[0113] Table 4

[0114] Table 5

[0115] Table 6

[0116] Table 7

[0117] Table 8

[0118] Table 9

[0119] Table 10

[0120] [Table 11]

[0121] Examples 1-14, 16, 29-37, 39-40, and 50-64, where the value of formula (A) is between 2% and 6%, have a dielectric loss tangent of 0.005 or less at 35 GHz, a surface devitrification temperature of 1400°C or less, and an elution amount of glass components in the acid resistance evaluation of 0.02 mg / cm³. 2 The following conditions were met, and the haze evaluation was A. For Examples 41 to 46, where the value of equation (A) was 2% or more and 6% or less, the dielectric loss tangent at 35 GHz was 0.005 or less, the surface devitrification temperature was 1400°C or less, and the amount of glass component eluted in the acid resistance evaluation was 0.02 mg / cm³. 2 The following is an estimate of Hayes' rating, which is likely to be A. Examples 24 and 28, where the value of equation (A) was greater than 6%, had a Hays evaluation of B or C. Example 21, in which the B2O3 content exceeds 35%, the MgO content is less than 1%, and the value of formula (A) is less than 2%, has a surface devitrification temperature of over 1400°C and the amount of glass component eluted in the acid resistance evaluation is 0.02 mg / cm³. 2 It was incredible. Examples 1-16, 29-37, 39-40, and 50-63, where the value of formula (B) is between -3% and 2%, have a surface devitrification temperature of 1400°C or less, and the amount of glass component eluted in the acid resistance evaluation is 0.02 mg / cm³. 2 The following was the result, and Hayes' evaluation was A. In Example 27, where the Al2O3 content is less than 2%, the B2O3 content is more than 35%, and the value of formula (B) is less than -3%, the amount of glass component eluted in the acid resistance evaluation was 0.02 mg / cm³. 2 It was excellent, and Hayes' rating was C. Example 23, in which the MgO content is less than 1%, the value of formula (A) is less than 2%, and the value of formula (B) is greater than 2%, has a surface devitrification temperature of over 1400°C and a glass component elution rate of 0.02 mg / cm³ in the acid resistance evaluation. 2 It was excellent, and Hayes' rating was C. Example 22, in which the MgO content is less than 1%, the value of formula (A) is less than 2%, and the value of formula (B) is greater than 2%, has a surface devitrification temperature of over 1400°C and the amount of glass component eluted in the acid resistance evaluation is 0.02 mg / cm³. 2 It was excellent, and Hayes' rating was C. In Example 20, where the Al2O3 content was greater than 6%, the B2O3 content was less than 18%, the value of formula (A) was greater than 6%, and the value of formula (B) was less than -3%, the dielectric loss tangent at 35 GHz was greater than 0.005. In Example 25, where the value of formula (A) was greater than 6% and the value of formula (B) was less than -3%, the amount of glass component eluted in the acid resistance evaluation was 0.02 mg / cm³. 2 It was excellent, and Hayes' rating was C. In Example 26, where the Al2O3 content is less than 2%, the value of formula (A) is greater than 6%, and the value of formula (B) is less than -3%, the amount of glass component eluted in the acid resistance evaluation was 0.02 mg / cm³. 2 It was excellent, and Hayes' rating was C. Examples 17 and 18, where the MgO content is less than 1%, and Example 19, where the MgO content is less than 1% and the BaO content is more than 3%, showed an elution amount of glass components of 0.02 mg / cm³ during the acid resistance evaluation. 2 It was incredible. Examples 47 to 49, where the Al2O3 content is greater than 6%, the B2O3 content is less than 18%, the value of formula (A) is greater than 6%, and the value of formula (B) is less than -3%, are estimated to have a dielectric loss tangent greater than 0.005 at 35 GHz. Examples 1-14, 16, 29-37, 39-40, and 50-64, where the value of equation (C) is between 88% and 93%, tend to show lower dielectric loss tangent, relative permittivity, and temperature T2 at 35 GHz and 10 GHz. Similarly, for Examples 41-46, where the value of equation (C) is between 88% and 93%, it is estimated that there will also be a tendency for lower dielectric loss tangent, relative permittivity, and temperature T2 at 35 GHz and 10 GHz. Examples 1-14, 16, 29-37, 39-40, and 50-64, where the value of formula (D) is between 0.1 and 0.3, tend to show a lower amount of glass component leaching during acid resistance evaluation. Examples 41-46, where the value of formula (D) is between 0.10 and 0.3, are also presumed to show a lower amount of glass component leaching during acid resistance evaluation. Examples 1-10, 12, 16, 30-35, and 50-64, where the value of formula (E) is 0.5 or higher, tend to show a lower amount of glass component leaching in the acid resistance evaluation and a better haze evaluation. It is also estimated that Examples 41-43, where the value of formula (E) is 0.5 or higher, tend to show a lower amount of glass component leaching in the acid resistance evaluation and a better haze evaluation. Examples 1-11, 14, 16, 29-33, 35, 40, 55-58, 63, and 64, where the value of formula (F) is between 0.5 and 1.2, tend to show a lower surface devitrification temperature, lower elution of glass components in acid resistance evaluation, and a better haze evaluation. It is also estimated that examples 41-46, where the value of formula (F) is between 0.5 and 1.2, tend to show a lower surface devitrification temperature, lower elution of glass components in acid resistance evaluation, and a better haze evaluation. Examples 6-8, 10, 14, 16, 29-37, 39-40, 50-52, and 57-64, where the value of equation (G) is 0.5 or greater, tend to show lower dielectric loss tangent, relative permittivity, Tg, temperature T2, and temperature T4 at 35 GHz and 10 GHz. It is also estimated that examples 41-46, where the value of equation (G) is 0.5 or greater, tend to show lower dielectric loss tangent, relative permittivity, Tg, temperature T2, and temperature T4 at 35 GHz and 10 GHz. Examples 1-9, 14, 16, 29-35, 37, 40, 50-53, and 57-60, where the value of formula (H) is between 0.01 and 5, tend to show a lower amount of glass component leaching in the acid resistance evaluation and a better haze evaluation. It is also estimated that examples 41-46, where the value of formula (H) is between 0.01 and 5, tend to show a lower amount of glass component leaching in the acid resistance evaluation and a better haze evaluation. Examples 5-12, 14, 16, 29-37, 39, 40, and 50-64, where the value of formula (I) is between 20% and 40%, tend to show lower dielectric loss tangent, relative permittivity, and elution of glass components in acid resistance evaluations at 35 GHz and 10 GHz. For Examples 41 to 46, where the value of equation (I) is between 20% and 40%, it is estimated that the dielectric loss tangent, relative permittivity, and the amount of glass component leached in the acid resistance evaluation tend to be lower at 35 GHz and 10 GHz. Examples 1-9, 11-14, 16, 29-35, 39, 40, and 50-64, where the value of formula (J) is between 0.05 and 2, tend to show lower dielectric loss tangent, relative permittivity, and the amount of glass component leached in the acid resistance evaluation at 35 GHz and 10 GHz. It is also estimated that Examples 41-46, where the value of formula (J) is between 0.05 and 2, tend to show lower dielectric loss tangent, relative permittivity, and the amount of glass component leached in the acid resistance evaluation at 35 GHz and 10 GHz. Examples 1 to 14, 16, 29 to 37, 39, 40, and 50 to 64, which satisfy -0.0003 ≤ (tanδ100 - tanδ10) ≤ 0.0003, demonstrate that the deterioration of the dielectric loss tangent tanδ can be suppressed even when rapidly cooled during glass fabrication. Examples 41 to 46, which satisfy -0.0003 ≤ (tanδ100 - tanδA) ≤ 0.0003, suggest that the deterioration of the dielectric loss tangent tanδ can be suppressed even when rapidly cooled during glass fabrication.

[0122] Although the present invention has been described in detail and 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 invention. This application is based on Japanese Patent Application No. 2020-143080 filed on 27 August 2020 and Japanese Patent Application No. 2021-009791 filed on 25 January 2021, the contents of which are incorporated herein by reference. [Industrial applicability]

[0123] The glass of the present invention has a low surface devitrification temperature, excellent acid resistance and phase separation characteristics, and can reduce dielectric loss of high-frequency signals. Glass plates containing such alkali-free glass are useful in a wide range of high-frequency electronic devices that handle high-frequency signals exceeding 10 GHz, especially those exceeding 30 GHz, and even those exceeding 35 GHz, such as glass substrates for communication equipment, frequency filter components such as SAW devices and FBARs, bandpass filters such as waveguides and SIW (Substrate Integrated Waveform) components, radar components, antenna components (especially liquid crystal antennas which are considered ideal for satellite communications), window glass, and vehicle window glass. [Explanation of Symbols]

[0124] 1: Circuit board 2: Glass substrate 2a, 2b: Main surface 3,4: Wiring layer

Claims

[Claim 1] In mole percent based on oxides Yes ２ 50-80%, Al ２ O ３ 2~6%、 B ２ O ３ 18~35%、 MgO 1-6%, CaO 0-6%, SrO 0-6%, It contains 0-3% BaO, Equation (A) is [MgO] + [CaO] + [SrO] + [BaO], and the value of equation (A) is 2% or more and 6% or less. Equation (B) is [Al ２ O ３ Alkali-free glass having the formula ]-([MgO] + [CaO] + [SrO] + [BaO]) and the value of formula (B) being -3% or more and 2% or less.

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