glass plate

Abstract

A glass sheet according to the present invention is characterized by containing, as a glass composition, 50-72 mass% of SiO2, 0-22 mass% of Al2O3, 15-38 mass% of B2O3, 0-3 mass% of Li2O + Na2O + K2O, and 0-12 mass% of MgO + CaO + SrO +BaO, and having a relative permittivity of at most 5 at 25°C and a frequency of 10 GHz.

Description

[Technical Field]

[0001] The present invention relates to a glass plate, and more particularly to a glass plate suitable for use in high-frequency devices. [Background technology]

[0002] Currently, development is underway to support the fifth-generation mobile communication system (5G), and technical studies are being conducted to increase the system's speed, increase transmission capacity, and reduce latency.

[0003] For example, Patent Document 1 discloses forming through holes in a glass plate in the thickness direction to provide an electrical signal path. Specifically, it discloses irradiating a glass plate with a laser to form an etching path, and then using a hydroxide-based etching material to form a plurality of through holes extending from the main surface of the glass plate along the etching path. The glass plate described in Patent Document 1 can also be used in high-frequency devices for 5G communication. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2018-531205 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0005] 5G communications will use radio waves with frequencies of several GHz or higher, and materials used in high-frequency devices for 5G communications will need to have low dielectric properties to reduce loss in transmitted signals.

[0006] However, Patent Document 1 does not describe any glass having low dielectric constant properties, and therefore cannot meet the above needs.

[0007] The present invention has been made in view of the above circumstances, and its technical object is to provide a glass sheet having low dielectric constant characteristics. [Means for solving the problem]

[0008] The inventors have conducted various experiments and found that the above technical problems can be solved by restricting the glass composition to a predetermined range, and have proposed this finding as the present invention. Specifically, the glass plate of the present invention has a glass composition containing, by mass%, 50-72% SiO2, 0-22% Al2O, 15-38% BO3, 0-3% Li2O + Na2O + KO, and 0-12% MgO + CaO + SrO + BaO, and is characterized by having a dielectric constant of 5 or less at 25°C and a frequency of 10 GHz. Here, "Li2O + Na2O + KO" refers to the total amount of Li2O, Na2O, and KO. "MgO + CaO + SrO + BaO" refers to the total amount of MgO, CaO, SrO, and BaO. The "dielectric constant at 25°C and a frequency of 10 GHz" can be measured, for example, by a well-known cavity resonator method.

[0009] The glass plate of the present invention contains 15% by mass or more of B2O3 in the glass composition. This allows for a reduction in the relative dielectric constant and dielectric loss tangent. Furthermore, the glass of the present invention restricts the content of Li2O + Na2O + K2O in the glass composition to 3% by mass or less, and the content of MgO + CaO + SrO + BaO to 12% by mass or less. This facilitates a reduction in density, making it easier to reduce the weight of high-frequency devices.

[0010] The glass plate of the present invention is characterized by having a glass composition containing, in mass %, 50 to 72% SiO2, 0 to 22% Al2O3, 15 to 38% B2O3, 0 to 3% Li2O+Na2O+K2O, and 0 to 12% MgO+CaO+SrO+BaO, and having a relative dielectric constant at 25°C and a frequency of 2.45 GHz of 5 or less. Here, the "relative dielectric constant at 25°C and a frequency of 2.45 GHz" can be measured, for example, by a well-known cavity resonator method.

[0011] The glass plate of the present invention is characterized by having a glass composition containing, in mass %, 50 to 72% of SiO2, 0 to 22% of Al2O3, 15 to 38% of B2O3, 0 to 3% of Li2O+Na2O+K2O, and 0 to 12% of MgO+CaO+SrO+BaO.

[0012] Furthermore, the glass plate of the present invention has a relative dielectric constant of 5 or less at 25° C. and a frequency of 10 GHz, which makes it possible to reduce transmission loss when an electric signal is transmitted to a high-frequency device.

[0013] Furthermore, the glass plate of the present invention preferably has a mass ratio (MgO+CaO+SrO+BaO) / (SiO2+Al2O3+B2O3) of 0.001 to 0.4, which makes it possible to improve the dimensional accuracy of through holes when they are formed in the glass plate by etching, without unduly increasing the manufacturing cost of the glass plate.

[0014] The glass plate of the present invention preferably has a plurality of through holes formed in the plate thickness direction, which allows a wiring structure for establishing electrical continuity between both surfaces of the glass plate to be formed, making it easier to apply the glass plate to high-frequency devices.

[0015] Furthermore, the glass plate of the present invention preferably has through holes with an average inner diameter of 300 μm or less, which makes it easier to increase the density of a wiring structure for establishing electrical continuity between both surfaces of the glass plate.

[0016] In addition, in the glass plate of the present invention, the difference between the maximum and minimum inner diameters of the through holes is preferably 50 μm or less, which can prevent the wiring for establishing electrical continuity between the two surfaces of the glass plate from becoming unduly long, thereby reducing transmission loss.

[0017] Furthermore, the glass plate of the present invention preferably has a maximum length of cracks extending from the through holes in the surface direction of 100 μm or less. This makes it easier to avoid a situation in which the cracks extend and the glass plate breaks when tensile stress is applied around the through holes during the production of high-frequency devices. Here, the "maximum length of the cracks extending from the through holes in the surface direction" refers to a value measured along the shape of the crack when the through holes are observed with an optical microscope from the front and back sides of the glass plate, and is not a value measured by measuring the distance between the start and end points of the crack, nor is it a value measured by measuring the length of the crack in the thickness direction.

[0018] Furthermore, the glass plate of the present invention preferably has a dielectric loss tangent of 0.01 or less at 25°C and a frequency of 10 GHz. This reduces transmission loss when an electrical signal is transmitted to a high-frequency device. Here, the "dielectric loss tangent at 25°C and a frequency of 10 GHz" can be measured, for example, by the well-known cavity resonator method.

[0019] The glass plate of the present invention preferably has a Young's modulus of 40 GPa or more. This makes the glass plate less likely to bend, which makes it easier to reduce wiring defects when manufacturing high-frequency devices. Here, "Young's modulus" can be measured, for example, by a well-known resonance method.

[0020] Furthermore, the glass plate of the present invention preferably has a thermal shrinkage of 30 ppm or less when heated at a rate of 5°C / min, held at 500°C for 1 hour, and cooled at a rate of 5°C / min. This makes the glass plate less susceptible to thermal shrinkage during the heat treatment process used to fabricate high-frequency devices, thereby facilitating the reduction of wiring defects during the fabrication of high-frequency devices. The "thermal shrinkage when heated at a rate of 5°C / min, held at 500°C for 1 hour, and cooled at a rate of 5°C / min" refers to a value measured by the following method. First, a linear marking is made at a predetermined location on the measurement sample, and then the measurement sample is folded perpendicular to the marking to separate it into two glass pieces. Next, only one of the glass pieces is subjected to a predetermined heat treatment (heated from room temperature at a rate of 5°C / min, held at 500°C for 1 hour, and cooled at a rate of 5°C / min). The heat-treated glass piece and the unheat-treated glass piece are then lined up and fixed together with adhesive tape, and the misalignment of the markings is measured. When the deviation of the marking is ΔL and the length of the sample before heat treatment is L0, the thermal shrinkage rate is calculated using the formula ΔL / L0 (unit: ppm).

[0021] The glass plate of the present invention has a thermal expansion coefficient of 20×10 in the temperature range of 30 to 380°C. -7 ~50×10 -7 / °C. This makes it easier to bond a low-expansion material such as silicon to the glass plate, making it easier to apply to high-frequency devices. Here, the "coefficient of thermal expansion in the temperature range of 30 to 380°C" can be measured, for example, with a dilatometer.

[0022] In addition, the glass plate of the present invention has a difference between the thermal expansion coefficient in the temperature range of 20 to 300°C and the thermal expansion coefficient in the temperature range of 20 to 200°C (the value obtained by subtracting the thermal expansion coefficient in the temperature range of 20 to 200°C from the thermal expansion coefficient in the temperature range of 20 to 300°C) of 1.0 × 10 -7 / °C or less. This reduces the change in the thermal expansion coefficient of the glass plate even when the heat treatment temperature changes during the manufacturing process of the high-frequency device, thereby reducing warping of the high-frequency device due to the difference in the thermal expansion coefficient between the glass plate and a low-expansion material such as silicon attached to the glass plate. As a result, the yield of high-frequency devices can be increased. Here, the "thermal expansion coefficient" in each temperature range can be measured, for example, with a dilatometer.

[0023] The glass plate of the present invention preferably has an external transmittance of 80% or more at a wavelength of 355 nm and a thickness of 1.0 mm. Here, the "external transmittance at a wavelength of 355 nm and a thickness of 1.0 mm" can be measured using a measurement sample having both surfaces polished to optically polished surfaces (mirror surfaces) with a commercially available spectrophotometer (for example, V-670 manufactured by JASCO Corporation).

[0024] The glass plate of the present invention preferably has an external transmittance of 15% or more at a wavelength of 265 nm and a thickness of 1.0 mm. Here, the "external transmittance at a wavelength of 265 nm and a thickness of 1.0 mm" can be measured using a measurement sample having both surfaces optically polished (mirror-polished) with a commercially available spectrophotometer (for example, V-670 manufactured by JASCO Corporation).

[0025] The glass plate of the present invention has a liquidus viscosity of 10 4.0 A viscosity of dPa·s or higher is preferable. This makes the glass less susceptible to devitrification during molding, making it easier to reduce the manufacturing costs of glass sheets. Here, "liquidus viscosity" refers to the value of the viscosity of glass at the liquidus temperature, measured using the platinum ball pull-up method. "Liquidus temperature" refers to the value measured when glass powder that passes through a standard 30 mesh (500 μm) sieve and remains on a 50 mesh (300 μm) sieve is placed in a platinum boat and held in a temperature gradient furnace for 24 hours, at which point crystals precipitate.

[0026] The glass sheet of the present invention is preferably formed by an overflow downdraw method, which can improve the surface precision of the glass sheet and also facilitates reducing the manufacturing cost of the glass sheet. DETAILED DESCRIPTION OF THE INVENTION

[0027] The glass plate of the present invention is characterized by having a glass composition containing, in mass %, 50-72% SiO2, 0-22% Al2O3, 15-38% B2O3, 0-3% Li2O + Na2O + K2O, and 0-12% MgO + CaO + SrO + BaO. The reasons for limiting the content of each component as described above are as follows. Note that the following % indications refer to mass % unless otherwise specified.

[0028] The SiO2 content is 50 to 72%, preferably 53 to 71%, 55 to 70%, 57 to 69.5%, 58 to 69%, 59 to 70%, 60 to 69%, and particularly 62 to 67%. If the SiO2 content is too low, the density tends to be high. On the other hand, if the SiO2 content is too high, the high-temperature viscosity increases, which not only reduces the melting property but also makes it easy for devitrified crystals such as cristobalite to precipitate during molding.

[0029] Al2O3 is a component that increases Young's modulus and also suppresses phase separation to maintain weather resistance. Therefore, the lower limit of Al2O3 is 0% or more, preferably 0.1% or more, 0.2% or more, 0.3% or more, 0.4% or more, 0.5% or more, 1% or more, 2% or more, 3% or more, 4% or more, 5% or more, and particularly 6% or more. On the other hand, if the Al2O3 content is too high, the liquidus temperature becomes high and devitrification resistance tends to decrease. Therefore, the upper limit range of Al2O3 is 22% or less, and is preferably 20% or less, 19% or less, 18% or less, 17% or less, 15% or less, 13% or less, 12% or less, 11% or less, 10.9% or less, 10.8% or less, 10.7% or less, 10.6% or less, 10.5% or less, 10% or less, 9.9% or less, 9.8% or less, 9.7% or less, 9.6% or less, 9.5% or less, 9.4% or less, 9.3% or less, 9.2% or less, 9.1% or less, 9.0% or less, 8.9% or less, 8.7% or less, 8.5% or less, 8.3% or less, 8.1% or less, 8% or less, 7.9% or less, 7.8% or less, 7.7% or less, 7.6% or less, 7.5% or less, 7.3% or less, 7.1% or less, and particularly 7.0% or less.

[0030] B2O3 is a component that reduces the dielectric loss and dielectric dissipation factor, as well as the Young's modulus and density. However, if the B2O3 content is too low, it becomes difficult to maintain low dielectric properties. In addition, its function as a flux becomes insufficient, resulting in high-temperature viscosity and a tendency toward reduced foam quality. It also becomes difficult to achieve low density. Therefore, the lower limit of B2O3 is 15% or more, preferably 18% or more, 18.1% or more, 18.2% or more, 18.3% or more, 18.4% or more, 18.5% or more, 19% or more, 19.4% or more, 19.5% or more, 19.6% or more, 20% or more, more than 20%, 22% or more, 24% or more, 25% or more, 25.1% or more, 25.3% or more, 25.5% or more, and particularly 25.6% or more. On the other hand, if the B2O3 content is too high, the heat resistance and chemical durability tend to decrease, and weather resistance tends to decrease due to phase separation. Therefore, the upper limit of B2O3 is 38% or less, and preferably 35% or less, 33% or less, 32% or less, 31% or less, 30% or less, 28% or less, or 27% or less.

[0031] The B2O3-Al2O3 content is preferably -5% or more, -4% or more, -3% or more, -2% or more, -1% or more, 0% or more, 1% or more, 2% or more, 3% or more, 4% or more, 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, and particularly 10% or more. If the B2O3-Al2O3 content is too low, it becomes difficult to ensure low dielectric properties. Note that "B2O3-Al2O3" is the B2O3 content minus the Al2O3 content.

[0032] Alkali metal oxides are components that improve meltability and formability, but if their content is too high, the density increases, water resistance decreases, and the thermal expansion coefficient becomes unduly high, reducing thermal shock resistance and making it difficult to match the thermal expansion coefficient of surrounding materials. Therefore, the content of Li2O + Na2O + K2O is 0 to 3%, preferably 0 to 2%, 0 to 1%, 0 to 0.5%, 0 to 0.2%, or 0 to 0.1%, and particularly 0.001 to less than 0.05%. The respective contents of Li2O, Na2O, and K2O are preferably 0 to 3%, 0 to 2%, 0 to 1%, 0 to 0.5%, 0 to 0.2%, or 0 to 0.1%, and particularly 0.001 to less than 0.01%.

[0033] Alkaline earth metal oxides are components that lower the liquidus temperature, making it difficult for devitrification crystals to form in the glass, and also improve meltability and formability. The content of MgO+CaO+SrO+BaO is 0-12%, preferably 0-10%, 0-8%, 0-7%, 1-7%, 2-7%, 3-9%, and particularly 3-6%. If the content of MgO+CaO+SrO+BaO is too low, devitrification resistance tends to decrease, and the glass is unable to fully function as a flux, resulting in decreased meltability. On the other hand, if the content of MgO+CaO+SrO+BaO is too high, the density increases, making it difficult to reduce the weight of the glass. In addition, the thermal expansion coefficient becomes unduly high, resulting in decreased thermal shock resistance.

[0034] MgO is a component that reduces high-temperature viscosity and improves meltability without lowering the strain point, and is the component that is least likely to increase density among alkaline earth metal oxides. The MgO content is preferably 0 to 12%, 0 to 10%, 0.01 to 8%, 0.1 to 6%, 0.2 to 5%, 0.3 to 4%, or 0.5 to 3%, and particularly preferably 1 to 2%. However, if the MgO content is too high, the liquidus temperature rises, and devitrification resistance tends to decrease. Furthermore, the glass undergoes phase separation, which tends to decrease transparency.

[0035] CaO is a component that reduces high-temperature viscosity and significantly improves meltability without lowering the strain point, and is also a component that is highly effective in improving devitrification resistance in the glass composition of the present invention. Therefore, the preferred lower limit of CaO is 0% or more, 0.05% or more, 0.1% or more, 1% or more, 1.1% or more, 1.2% or more, 1.3% or more, 1.4% or more, 1.5% or more, and particularly 2% or more. On the other hand, if the CaO content is too high, the thermal expansion coefficient and density may increase unduly, and the component balance of the glass composition may be impaired, which may actually reduce devitrification resistance. Therefore, the preferred upper limit of CaO is 12% or less, 10% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4.6% or less, 4.5% or less, 4.4% or less, 4% or less, and particularly 3% or less.

[0036] SrO is a component that reduces high-temperature viscosity and improves meltability without lowering the strain point, but if the SrO content is too high, the liquidus viscosity tends to decrease. Therefore, the SrO content is preferably 0 to 10%, 0 to 8%, 0 to 7%, 0 to 6%, 0 to 5.1%, 0 to 5%, 0 to 4.9%, 0 to 4%, 0 to 3%, 0 to 2%, 0 to 1.5%, 0 to 1%, 0 to 0.5%, and particularly preferably 0 to 0.1%.

[0037] BaO is a component that reduces high-temperature viscosity and improves meltability without lowering the strain point, but if the BaO content is too high, the liquidus viscosity tends to decrease. Therefore, the BaO content is preferably 0 to 10%, 0 to 8%, 0 to 7%, 0 to 6%, 0 to 5%, 0 to 4%, 0 to 3%, 0 to 2%, 0 to 1.5%, 0 to 1%, 0 to 0.5%, and particularly preferably 0 to less than 0.1%.

[0038] If the mass ratio (MgO + CaO + SrO + BaO) / (SiO2 + Al2O3 + B2O3) is too large, not only will the weather resistance be reduced, but when forming through-holes by etching, the etching rate will be increased, and the shape of the through-holes will tend to be distorted. Furthermore, when forming through-holes by laser irradiation, the drilling accuracy will tend to be reduced. On the other hand, if the mass ratio (MgO + CaO + SrO + BaO) / (SiO2 + Al2O3 + B2O3) is too small, the high-temperature viscosity will increase, and the melting temperature will become higher, which will likely increase the manufacturing cost of the glass sheet. Therefore, the mass ratio (MgO+CaO+SrO+BaO) / (SiO2+Al2O3+B2O3) is preferably 0.001 to 0.4, 0.005 to 0.35, 0.010 to 0.30, 0.020 to 0.25, 0.030 to 0.20, 0.035 to 0.15, 0.040 to 0.14, 0.045 to 0.13, and particularly 0.050 to 0.10. Note that the "mass ratio (MgO+CaO+SrO+BaO) / (SiO2+Al2O3+B2O3)" refers to the value obtained by dividing the content of MgO+CaO+SrO+BaO by the content of SiO2+Al2O3+B2O3.

[0039] If the mass ratio (MgO + CaO + SrO + BaO) / Al2O3 is too small, the devitrification resistance decreases, making it difficult to form into a plate by the overflow downdraw method. On the other hand, if the mass ratio (MgO + CaO + SrO + BaO) / Al2O3 is too large, the density and thermal expansion coefficient may increase unduly. Therefore, the mass ratio (MgO + CaO + SrO + BaO) / Al2O3 is preferably 0.1 to 1.5, 0.1 to 1.2, 0.2 to 1.2, 0.3 to 1.2, 0.4 to 1.1, and particularly 0.5 to 1.0. Note that "(MgO + CaO + SrO + BaO) / Al2O3" refers to the value obtained by dividing the content of MgO + CaO + SrO + BaO by the content of Al2O3.

[0040] The mass ratio (SrO+BaO) / B2O3 is preferably 0.5 or less, 0.2 or less, 0.1 or less, 0.05 or less, 0.03 or less, and particularly preferably 0.02 or less. If the mass ratio (SrO+BaO) / B2O3 is too large, it becomes difficult to ensure low dielectric properties and to increase the liquidus viscosity. Note that "SrO+BaO" refers to the total amount of SrO and BaO. Furthermore, "(SrO+BaO) / B2O3" refers to the value obtained by dividing the content of SrO+BaO by the content of B2O3.

[0041] The mass ratio B2O3 / (SrO+BaO) is preferably 2 or more, 5 or more, 10 or more, 20 or more, 30 or more, 40 or more, and particularly 50 or more. If the mass ratio (SrO+BaO) / B2O3 is too small, it becomes difficult to ensure low dielectric properties and to increase the liquidus viscosity. Note that "B2O3 / (SrO+BaO)" refers to the value obtained by dividing the B2O3 content by the SrO+BaO content.

[0042] B2O3-(MgO+CaO+SrO+BaO) is preferably 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, 10% or more, 11% or more, particularly 12% or more. If the content of B2O3-(MgO+CaO+SrO+BaO) is too low, it becomes difficult to ensure low dielectric properties, the density tends to increase, and the Young's modulus tends to decrease.

[0043] The mass ratio (SrO+BaO) / (MgO+CaO) is preferably not more than 400, not more than 300, not more than 100, not more than 50, not more than 10, not more than 5, not more than 2, not more than 1, not more than 0.8, not more than 0.5, particularly not more than 0.3. If the mass ratio (SrO+BaO) / (MgO+CaO) is too large, it becomes difficult to ensure low dielectric properties and the density tends to increase.

[0044] In addition to the above components, the following components may be incorporated into the glass composition.

[0045] ZnO is a component that improves meltability, but if it is included in a large amount in the glass composition, the glass becomes more susceptible to devitrification and the density also tends to increase. Therefore, the ZnO content is preferably 0 to 5%, 0 to 3%, 0 to 0.5%, 0 to 0.3%, particularly preferably 0 to 0.1%.

[0046] ZrO2 is a component that increases Young's modulus. The ZrO2 content is preferably 0 to 5%, 0 to 3%, 0 to 0.5%, 0 to 0.2%, 0 to 0.16%, 0 to 0.1%, particularly preferably 0 to 0.02%. If the ZrO2 content is too high, the liquidus temperature rises, making it easier for devitrified zircon crystals to precipitate.

[0047] TiO2 is a component that reduces high-temperature viscosity, improves meltability, and suppresses solarization, but if it is included in a large amount in the glass composition, the glass becomes colored and transmittance tends to decrease. Therefore, the TiO2 content is preferably 0 to 5%, 0 to 3%, 0 to 1%, 0 to 0.1%, and particularly preferably 0 to 0.02%.

[0048] P2O5 is a component that improves devitrification resistance, but if it is included in a large amount in the glass composition, the glass may undergo phase separation, become opalescent, and have a risk of significantly reducing water resistance. Therefore, the P2O5 content is preferably 0 to 5%, 0 to 1%, 0 to 0.5%, and particularly preferably 0 to 0.1%.

[0049] SnO2 is a component that has an excellent fining effect in the high temperature range and also reduces high-temperature viscosity. The SnO2 content is preferably 0 to 1%, 0.01 to 0.5%, 0.05 to 0.3%, and particularly 0.1 to 0.3%. If the SnO2 content is too high, devitrified crystals of SnO2 are likely to precipitate in the glass.

[0050] Fe2O3 is a component that can be introduced as an impurity component or a fining agent component. However, if the Fe2O3 content is too high, there is a risk of a decrease in ultraviolet transmittance. Therefore, the Fe2O3 content is preferably 0.05% or less, 0.03% or less, and particularly 0.02% or less. Here, "Fe2O3" as used in the present invention includes divalent iron oxide and trivalent iron oxide, and divalent iron oxide is handled in terms of Fe2O3. Note that other oxides are also handled in the same manner, based on the oxide indicated.

[0051] As a fining agent, addition of SnO2 is preferred, but as long as the glass properties are not impaired, CeO2, SO3, C, and metal powder (such as Al, Si, etc.) may be added up to 1% as a fining agent.

[0052] As2O3, Sb2O3, F, and Cl also function effectively as fining agents, and the present invention does not exclude the inclusion of these components. However, from an environmental perspective, it is preferable that the content of each of these components be less than 0.1%, and particularly less than 0.05%.

[0053] The glass plate of the present invention preferably has the following properties.

[0054] The relative dielectric constant at 25°C and a frequency of 10 GHz is preferably 5.0 or less, 4.9 or less, 4.8 or less, 4.7 or less, 4.6 or less, particularly preferably 4.5 or less. If the relative dielectric constant at 25°C and a frequency of 10 GHz is too high, transmission loss when an electric signal is transmitted to a high-frequency device is likely to increase.

[0055] The dielectric loss tangent at 25°C and a frequency of 10 GHz is preferably 0.01 or less, 0.009 or less, 0.008 or less, 0.007 or less, 0.006 or less, 0.005 or less, 0.004 or less, particularly preferably 0.003 or less. If the dielectric loss tangent at 25°C and a frequency of 10 GHz is too high, transmission loss when an electrical signal is transmitted to a high-frequency device is likely to increase.

[0056] The relative dielectric constant at 25°C and a frequency of 2.45 GHz is preferably 5.0 or less, 4.9 or less, 4.8 or less, 4.7 or less, 4.6 or less, particularly preferably 4.5 or less. If the relative dielectric constant at 25°C and a frequency of 10 GHz is too high, transmission loss when an electric signal is transmitted to a high-frequency device is likely to increase.

[0057] The dielectric loss tangent at 25°C and a frequency of 2.45 GHz is preferably 0.01 or less, 0.009 or less, 0.008 or less, 0.007 or less, 0.006 or less, 0.005 or less, 0.004 or less, particularly preferably 0.003 or less. If the dielectric loss tangent at 25°C and a frequency of 10 GHz is too high, transmission loss when an electrical signal is transmitted to a high-frequency device is likely to increase.

[0058] The Young's modulus is preferably 40 GPa or more, 41 GPa or more, 43 GPa or more, 45 GPa or more, 47 GPa or more, 50 GPa or more, 51 GPa or more, 52 GPa or more, 53 GPa or more, 54 GPa or more, particularly 55 GPa or more. If the Young's modulus is too low, the glass plate will be easily bent, which will easily cause wiring defects during the production of high-frequency devices.

[0059] The thermal shrinkage when the temperature is increased at a rate of 5°C / min, held at 500°C for 1 hour, and cooled at a rate of 5°C / min is preferably 30 ppm or less, 25 ppm or less, 20 ppm or less, particularly 18 ppm or less. If the thermal shrinkage when the temperature is increased at a rate of 5°C / min, held at 500°C for 1 hour, and cooled at a rate of 5°C / min is too large, the glass plate is likely to undergo thermal shrinkage in the heat treatment step during the production of a high-frequency device, which makes wiring defects more likely to occur during the production of the high-frequency device.

[0060] The thermal expansion coefficient in the temperature range of 30 to 380°C is preferably 20 x 10 -7 ~50×10 -7 / ℃, 22×10 -7 ~48×10 -7 / ℃, 23×10 -7 ~47×10 -7 / ℃, 25×10 -7 ~46×10 -7 / ℃, 28×10 -7~45×10 -7 / ℃, 30×10 -7 ~43×10 -7 / ℃, 32×10 -7 ~41×10 -7 / ℃, especially 35×10 -7 ~39×10 -7 / ° C. If the thermal expansion coefficient in the temperature range of 30 to 380° C. is outside the above range, it becomes difficult to bond a low-expansion member such as silicon to the glass plate.

[0061] The thermal expansion coefficient in the temperature range of 20 to 200°C is preferably 21 x 10 -7 ~51×10 -7 / ℃, 22×10 -7 ~48×10 -7 / ℃, 23×10 -7 ~47×10 -7 / ℃, 25×10 -7 ~46×10 -7 / ℃, 28×10 -7 ~45×10 -7 / ℃, 30×10 -7 ~43×10 -7 / ℃, 32×10 -7 ~41×10 -7 / ℃, especially 35×10 -7 ~39×10 -7 / ° C. If the thermal expansion coefficient in the temperature range of 20 to 200° C. is outside the above range, it becomes difficult to bond a low-expansion member such as silicon to the glass plate.

[0062] The thermal expansion coefficient in the temperature range of 20 to 220°C is preferably 21 x 10 -7 ~51×10 -7 / ℃, 22×10 -7 ~48×10 -7 / ℃, 23×10 -7 ~47×10 -7 / ℃, 25×10 -7 ~46×10 -7 / ℃, 28×10 -7 ~45×10 -7 / ℃, 30×10 -7 ~43×10 -7 / ℃, 32×10 -7 ~41×10 -7 / ℃, especially 35×10 -7 ~39×10 -7 / ° C. If the thermal expansion coefficient in the temperature range of 20 to 220° C. is outside the above range, it becomes difficult to bond a low-expansion member such as silicon to the glass plate.

[0063] The thermal expansion coefficient in the temperature range of 20 to 260°C is preferably 21 x 10 -7 ~51×10 -7 / ℃, 22×10 -7 ~48×10 -7 / ℃, 23×10 -7 ~47×10 -7 / ℃, 25×10 -7 ~46×10 -7 / ℃, 28×10 -7 ~45×10 -7 / ℃, 30×10 -7 ~43×10 -7 / ℃, 32×10 -7 ~41×10 -7 / ℃, especially 35×10 -7 ~39×10 -7 / ° C. If the thermal expansion coefficient in the temperature range of 20 to 260° C. is outside the above range, it becomes difficult to bond a low-expansion member such as silicon to the glass plate.

[0064] The thermal expansion coefficient in the temperature range of 20 to 300°C is preferably 20 x 10 -7 ~50×10 -7 / ℃, 22×10 -7 ~48×10 -7 / ℃, 23×10 -7 ~47×10 -7 / ℃, 25×10 -7 ~46×10 -7 / ℃, 28×10 -7 ~45×10 -7 / ℃, 30×10 -7 ~43×10 -7 / ℃, 32×10 -7 ~41×10 -7 / ℃, especially 35×10 -7 ~39×10 -7 / ° C. If the thermal expansion coefficient in the temperature range of 20 to 300° C. is outside the above range, it becomes difficult to bond a low-expansion member such as silicon to the glass plate.

[0065] The difference between the thermal expansion coefficient in the temperature range of 20 to 300°C and the thermal expansion coefficient in the temperature range of 20 to 200°C is preferably 1.0 × 10 -7 / ℃ or less, more preferably -1.0×10 -7 / ℃ or more and 0.9×10 -7 / ℃ or less, preferably -0.8×10 -7 / ℃ or more and 0.7×10 -7 / ℃ or less, preferably -0.6×10 -7 / ℃ or more and 0.5×10 -7 / ℃ or less, preferably -0.4×10 -7 / ℃ or more and 0.3×10 -7 / °C or less, particularly preferably -0.3 × 10 -7 / ℃ or more and 0.2×10 -7 / °C or less. If there is a large difference between the thermal expansion coefficient in the temperature range of 20 to 300°C and the thermal expansion coefficient in the temperature range of 20 to 200°C, the change in the thermal expansion coefficient of the glass plate will be large when the heat treatment temperature changes during the manufacturing process of the high-frequency device, and the warping of the high-frequency device will increase due to the difference in the thermal expansion coefficient between the glass plate and a low-expansion member such as silicon attached to the glass plate.

[0066] The external transmittance at a wavelength of 1100 nm, converted into a thickness of 1.0 mm, is preferably 85% or more, 86% or more, 87% or more, 88% or more, 89% or more, 90% or more, particularly 91% or more. If the external transmittance at a wavelength of 1100 nm, converted into a thickness of 1.0 mm, is outside the above range, for example, when an infrared laser or the like is irradiated from the back side of the glass plate to peel and harden a resin layer or a high-frequency device adhered to the front surface of the glass plate, peeling and hardening do not go well, increasing the possibility of producing a defective product.

[0067] The external transmittance at a wavelength of 355 nm, converted into a thickness of 1.0 mm, is preferably 80% or more, 81% or more, 82% or more, 83% or more, 84% or more, 85% or more, particularly 86% or more. If the external transmittance at a wavelength of 355 nm, converted into a thickness of 1.0 mm, is outside the above range, for example, when an ultraviolet laser or the like is irradiated from the back side of the glass plate to peel off and harden a resin layer or a high-frequency device adhered to the surface of the glass plate, peeling and hardening do not go well, increasing the possibility of producing a defective product.

[0068] The external transmittance at a wavelength of 265 nm, converted into a thickness of 1.0 mm, is preferably 15% or more, 16% or more, 17% or more, 18% or more, 20% or more, 22% or more, particularly 23% or more. If the external transmittance at a wavelength of 265 nm, converted into a thickness of 1.0 mm, is outside the above range, for example, when a mercury lamp or the like is irradiated from the back side of the glass plate to peel off and harden a resin layer or a high-frequency device adhered to the surface of the glass plate, peeling and hardening do not go well, increasing the possibility of producing a defective product.

[0069] The liquidus viscosity is preferably 10 3.9 dPa·s or more, 10 4.0 dPa·s or more, 10 4.2 dPa·s or more, 10 4.6 dPa·s or more, 10 4.8 dPa·s or more, 10 5.0 dPa·s or more, especially 10 5.2 If the liquidus viscosity is too low, the glass is prone to devitrification during molding.

[0070] The strain point is preferably 480° C. or higher, 500° C. or higher, 520° C. or higher, 530° C. or higher, 540° C. or higher, 550° C. or higher, 560° C. or higher, 570° C. or higher, 580° C. or higher, particularly preferably 590° C. If the strain point is too low, the glass plate is likely to undergo thermal shrinkage in the heat treatment step during the production of a high-frequency device, which makes wiring defects more likely to occur during the production of the high-frequency device.

[0071] The β-OH value is preferably 1.1 mm -1 Below, 0.6mm -1 Below, 0.55mm-1 Below, 0.5mm -1 Below, 0.45mm -1 Below, 0.4mm -1 Below, 0.35mm -1 Below, 0.3mm -1 Below, 0.25mm -1 Below, 0.2mm -1 Below, 0.15mm -1 Below, especially 0.1 mm -1 If the β-OH value is too large, it becomes difficult to ensure low dielectric properties. The "β-OH value" is a value calculated using FT-IR according to the following formula:

[0072] β-OH value = (1 / X)log(T1 / T2) X: Plate thickness (mm) T1: Reference wavelength 3846cm -1 Transmittance (%) T2: Hydroxyl group absorption wavelength 3600cm -1 Minimum transmittance (%) in the vicinity

[0073] Fracture toughness K 1C is preferably 0.6 MPa m 0.5 More than 0.62MPa m 0.5 More than 0.65MPa m 0.5 More than 0.67MPa m 0.5 Over 0.69 MPa m 0.5 Above 0.7 MPa m 0.5 That's all. Fracture toughness K 1C If the fracture toughness K is too low, when a tensile stress is applied around the through-hole during the manufacture of a high frequency device, the cracks will extend and the glass plate will easily break. 1C " was measured using the Single-Edge-Precracked-Beam (SEPB) method based on JIS R1607 "Fracture Toughness Testing Method for Fine Ceramics." The SEPB method measures the maximum load until the specimen breaks in a three-point bending test of a precracked specimen, and calculates the plane strain fracture toughness K from the maximum load, precrack length, specimen dimensions, and distance between bending supports. 1CThis is a method to determine the fracture toughness K 1C The measured value is the average of five measurements.

[0074] The volume resistivity Logρ at 25°C is preferably 16 Ω·cm or more, 16.5 Ω·cm or more, 17 Ω·cm or more, and particularly 17.5 Ω·cm or more. If the volume resistivity Logρ at 25°C is too low, transmission signals tend to flow more easily to the glass plate side, which tends to increase transmission loss when electrical signals are transmitted to high-frequency devices. Note that "volume resistivity Logρ at 25°C" refers to a value measured in accordance with ASTM C657-78.

[0075] The thermal conductivity at 25°C is preferably 0.7 W / (m·K) or more, 0.75 W / (m·K) or more, 0.8 W / (m·K) or more, 0.85 W / (m·K) or more, and particularly 0.9 W / (m·K) or more. If the thermal conductivity at 25°C is too low, the heat dissipation ability of the glass plate will be reduced, and there is a risk that the temperature of the glass plate will rise excessively when the high-frequency device is in operation. Note that "thermal conductivity at 25°C" refers to a value measured in accordance with JIS R2616.

[0076] The water vapor permeability is preferably 1×10 -1 g / (m 2 ·24h) or less, 1×10 -2 g / (m 2 ·24h) or less, 1×10 -3 g / (m 2 ·24h) or less, 1×10 -4 g / (m 2 24h) or less, especially 1×10 -5 g / (m 2 If the water vapor permeability is too high, water vapor will be easily absorbed into the glass sheet, making it difficult to maintain low dielectric properties. The "water vapor permeability" can be measured using the known calcium method.

[0077] The glass plate of the present invention preferably has a through hole formed in the plate thickness direction, and more preferably has a plurality of through holes formed in the plate thickness direction. Furthermore, from the viewpoint of increasing the wiring density, the average inner diameter of the through holes is preferably 300 μm or less, 280 μm or less, 250 μm or less, 230 μm or less, 200 μm or less, 180 μm or less, 150 μm or less, 130 μm or less, 120 μm or less, 110 μm or less, 100 μm or less, and particularly 90 μm or less. However, if the average inner diameter of the through holes is too small, it becomes difficult to form a wiring structure for ensuring electrical continuity between both surfaces of the glass plate. Therefore, the average inner diameter of the through holes is preferably 10 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, and particularly 50 μm or more.

[0078] The difference between the maximum and minimum inner diameters of the through holes is preferably 50 μm or less, 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, particularly preferably 25 μm or less. If the difference between the maximum and minimum inner diameters of the through holes is too large, the length of the wiring for establishing electrical continuity between both surfaces of the glass plate becomes unnecessarily long, making it difficult to reduce transmission loss.

[0079] The maximum length of the crack extending from the through hole in the surface direction is preferably 100 μm or less, 50 μm or less, 30 μm or less, 10 μm or less, 5 μm or less, 3 μm or less, 1 μm or less, particularly 0.5 μm or less. If the maximum length of the crack extending from the through hole in the surface direction is too large, the crack will extend when tensile stress is applied around the through hole during production of a high-frequency device, making the glass plate more likely to break.

[0080] The amount of warping is preferably 100 μm or less, 90 μm or less, 80 μm or less, particularly preferably 70 μm or less. If the amount of warping is too large, wiring defects are likely to occur during the manufacture of high frequency devices.

[0081] The overall thickness deviation is preferably 5 μm or less, 4.8 μm or less, 4.5 μm or less, 4.3 μm or less, 4 μm or less, 3.5 μm or less, and particularly 3 μm or less. If the overall thickness deviation is too large, wiring defects are likely to occur during the manufacture of high-frequency devices. The "warpage amount" and "overall thickness deviation" are values ​​measured using a Bow / Warp measuring device SBW-331ML / d manufactured by Kobelco Research Institute Co., Ltd.

[0082] The shape of the glass plate is preferably rectangular or circular. This makes it easy to apply to the manufacturing processes of printed wiring boards and semiconductors. When the glass plate of the present invention is rectangular, the dimensions are preferably 300 × 400 mm or more, 305 × 405 mm or more, 310 × 410 mm or more, 315 × 415 mm or more, 320 × 420 mm or more, particularly 325 × 425 mm or more. If the dimensions of the glass plate are too small, it becomes difficult to obtain multiple panels in the manufacturing process of high-frequency devices, which tends to increase the manufacturing cost of high-frequency devices. When the glass plate is circular, the dimensions are φ500 mm or less, φ460 mm or less, φ400 mm or less, particularly φ310 mm or less. When the dimensions are too large in the case of a circular shape, it becomes difficult to apply to, for example, 6-inch semiconductor processes, 8-inch semiconductor processes, 12-inch semiconductor processes, 18-inch semiconductor processes, etc. in the manufacturing process of high-frequency devices.

[0083] The glass plate of the present invention is preferably provided with individual identification information. This makes it possible to identify the manufacturing history of each glass plate in the manufacturing process of a high-frequency device, facilitating investigation of the cause of product defects. Examples of methods for providing individual identification information to a glass plate include known laser ablation methods (evaporation of glass by irradiation with a pulsed laser), printing a barcode, and printing a QR code (registered trademark).

[0084] The glass plate of the present invention preferably has a thickness of 10 mm or less, 9 mm or less, 8 mm or less, 7 mm or less, 6 mm or less, 5 mm or less, 4 mm or less, 3 mm or less, 2 mm or less, 1 mm or less, 0.9 mm or less, 0.8 mm or less, 0.7 mm or less, 0.6 mm or less, 0.5 mm or less, 0.4 mm or less, particularly 0.3 mm or less. If the plate thickness is too large, it becomes difficult to reduce the weight and size of high-frequency devices.

[0085] The glass sheet of the present invention is preferably formed by an overflow downdraw method. In this way, an unpolished glass sheet having good surface quality can be efficiently obtained. In addition to the overflow downdraw method, various forming methods can be adopted. For example, forming methods such as a slot-down method, a float method, and a roll-out method can be adopted.

[0086] From the viewpoint of reducing the resistance loss of a high-frequency device, the arithmetic mean roughness Ra of the surface of the glass plate is preferably 100 nm or less, 50 nm or less, 20 nm or less, 10 nm or less, 5 nm or less, 2 nm or less, 1 nm or less, and particularly 0.5 nm or less. If the arithmetic mean roughness Ra of the surface of the glass plate is too large, the arithmetic mean roughness Ra of the metal wiring formed on the surface of the glass plate will be large, resulting in excessive resistance loss due to the so-called skin effect that occurs when current flows through the metal wiring of the high-frequency device. Furthermore, the strength of the glass plate will be reduced, making it more susceptible to breakage.

[0087] Furthermore, from the viewpoint of improving the manufacturing yield of high-frequency devices, the arithmetic mean roughness Ra of the surface of the glass plate is preferably 1 nm or more, 1.3 nm or more, 1.4 nm or more, 1.5 nm or more, 1.6 nm or more, 1.8 nm or more, 2 nm or more, 4 nm or more, 8 nm or more, 11 nm or more, 15 nm or more, 25 nm or more, 40 nm or more, 60 nm or more, 90 nm or more, 110 nm or more, 200 nm or more, 300 nm or more, and particularly 400 nm or more. If the arithmetic mean roughness Ra of the surface of the glass plate is too small, metal wiring formed on the surface of the glass plate and coating layers covering the surface of the glass plate are likely to peel off. As a result, the manufacturing yield of high-frequency devices is improved. The "arithmetic mean roughness Ra" can be measured using a stylus surface roughness meter or an atomic force microscope (AFM).

[0088] The glass plate of the present invention preferably does not have a surface compressive stress layer formed by ion exchange, which makes it easier to reduce the production cost of the glass plate.

[0089] The glass plate of the present invention is preferably used in a manufacturing process for a high-frequency device, more preferably in a semi-additive process, which allows the wiring width of the high-frequency device to be adjusted to the width required for the device.

[0090] The glass sheet of the present invention is preferably subjected to a process for forming passive components on the surface of the glass sheet, and the passive components preferably include at least one of a capacitor, a coil, and a resistor, such as an RF front-end module for a smartphone.

[0091] In the manufacturing process of a high-frequency device, the maximum processing temperature is preferably 350° C. or less, 345° C. or less, 340° C. or less, 335° C. or less, 330° C. or less, particularly preferably 325° C. If the maximum processing temperature is too high, the reliability of the high-frequency device is likely to decrease. [Example]

[0092] The present invention will be described in detail below based on examples. Note that the following examples are merely illustrative and the present invention is not limited to the following examples in any way.

[0093] Tables 1 to 13 show examples of the present invention (samples No. 1 to 104). In the tables, [Not yet] indicates that the measurement has not been performed.

[0094] [Table 1]

[0095] [Table 2]

[0096] [Table 3]

[0097] [Table 4]

[0098] [Table 5]

[0099] [Table 6]

[0100] [Table 7]

[0101] [Table 8]

[0102] [Table 9]

[0103] [Table 10]

[0104] [Table 11]

[0105] [Table 12]

[0106] [Table 13]

[0107] Samples Nos. 1 to 104 were prepared as follows. First, glass raw materials prepared to obtain the glass compositions shown in the table were placed in a platinum crucible, melted at 1600°C for 24 hours, and then poured onto a carbon plate to form a flat plate. Next, the density ρ, thermal expansion coefficient α, strain point Ps, annealing point Ta, softening point Ts, and 10 4.0 Temperature in dPa·s, 10 3.0 Temperature in dPa·s, 10 2.5 The temperature in dPa·s, Young's modulus E, liquidus temperature TL, liquidus viscosity logηTL, relative permittivity at 25°C and a frequency of 2.45 GHz, dielectric loss tangent at 25°C and a frequency of 2.45 GHz, relative permittivity at 25°C and a frequency of 10 GHz, dielectric loss tangent at 25°C and a frequency of 10 GHz, external transmittance converted to a thickness of 1.0 mm, and through-hole processing accuracy were evaluated. In this example, SnO2 was used as a fining agent, but fining agents other than SnO2 may also be used. Furthermore, if bubble removal is satisfactory through adjustment of the melting conditions and glass batch, the addition of a fining agent is not necessary.

[0108] The density ρ is a value measured by the well-known Archimedes method.

[0109] The thermal expansion coefficient α is a value measured with a dilatometer, and is an average value in the temperature ranges of 20 to 200°C, 20 to 220°C, 20 to 260°C, 20 to 300°C, and 30 to 380°C.

[0110] The strain point Ps, annealing point Ta and softening point Ts are values ​​measured based on the methods of ASTM C336 and C338.

[0111] 10 4.0 Temperature in dPa·s, 10 3.0 Temperature and 10 in dPa·s 2.5 The temperature at dPa·s was measured by the platinum sphere pulling method.

[0112] Young's modulus E is a value measured by the resonance method. The larger the Young's modulus, the larger the specific Young's modulus (Young's modulus / density) tends to be, and in the case of a flat plate, the deflection of the glass due to its own weight becomes smaller.

[0113] The liquidus temperature TL is the temperature at which crystals precipitate when glass powder that passes through a standard 30 mesh (500 μm) sieve and remains on a 50 mesh (300 μm) sieve is placed in a platinum boat and held in a temperature gradient furnace for 24 hours.

[0114] The liquidus viscosity logηTL is a value obtained by measuring the viscosity of the glass at the liquidus temperature TL by the platinum ball pull-up method.

[0115] The relative permittivity and dielectric loss tangent at 25°C and a frequency of 2.45 GHz and the relative permittivity and dielectric loss tangent at 25°C and a frequency of 10 GHz refer to values ​​measured by the well-known cavity resonator method.

[0116] The external transmittance at wavelengths of 265 nm, 305 nm, 355 nm, 365 nm, and 1100 nm, converted into a thickness of 1.0 mm, refers to the value measured using a sample that has been optically polished on both sides (mirror surface) using a commercially available spectrophotometer (for example, V-670 manufactured by JASCO Corporation).

[0117] The processing accuracy of the through holes was evaluated by setting the same processing conditions for each sample, and if the difference between the maximum and minimum inner diameters was less than 50 μm, it was marked as "○", and if the difference between the maximum and minimum inner diameters was 50 μm or more, it was marked as "×". [Example]

[0118] A glass batch having the glass composition of Sample No. 19 listed in Table 3 was melted in a test melting furnace to obtain molten glass, which was then formed into a glass plate having a thickness of 0.7 mm by the overflow downdraw method. During the formation of the glass plate, the thermal shrinkage, overall thickness deviation, and warpage of the glass plate were controlled by appropriately adjusting the speed of the tension roller, the speed of the cooling roller, the temperature distribution of the heating device, the temperature of the molten glass, the flow rate of the molten glass, the sheet drawing speed, the rotation speed of the stirring stirrer, and the like. The obtained glass plate was then cut into a circular glass plate having an outer diameter of 12 inches (304.8 mm). The amount of warpage of the circular glass plate was 100 μm or less, and the overall thickness deviation was 5 μm. The "amount of warpage" and "overall thickness deviation" were measured using a Bow / Warp measuring device SBW-331ML / d manufactured by Kobelco Research Institute, Inc. Next, the arithmetic mean roughness Ra of the surface of the obtained glass plate was measured with an atomic force microscope (AFM) and found to be 0.2 nm. [Example]

[0119] Glass batches having the glass compositions of Sample No. 19 listed in Table 3 and Sample No. 72 listed in Table 9 were melted in a test melting furnace to obtain molten glass, and then glass plates with a thickness of 0.3 mm were formed using the overflow downdraw method. The obtained glass plates were then cut to obtain rectangular glass plates measuring 300 mm x 400 mm. Next, multiple through holes were formed in the rectangular glass plates. The through holes were created by irradiating the surface of the glass plate with a commercially available picosecond laser to form a modified layer, and then removing the modified layer by etching. The inner diameters of the through holes of Sample No. 19 listed in Table 3 and Sample No. 91 listed in Table 12 were measured, and the maximum and minimum values ​​were 85 μm and 62 μm, respectively, with a difference between the maximum and minimum inner diameters being 23 μm. Furthermore, the maximum length of cracks extending from the through holes in the surface direction was 2 μm in both cases.

[0120] Next, high-frequency devices were fabricated using the glass plates according to Sample No. 19 in Table 3 and Sample No. 72 in Table 9. First, a conductor circuit layer was formed in the through-holes of the glass plate by a semi-additive method. Specifically, the conductor circuit layer was formed by sequentially fabricating a seed metal layer by sputtering, forming a metal layer by electroless plating, forming a resist pattern, and forming copper plating for wiring.

[0121] Next, capacitors, coils, etc. were provided on both surfaces of the glass plate, and then an insulating resin layer was formed to create via holes. This was followed by a desmearing process and electroless copper plating, followed by the formation of a dry film resist layer. A resist pattern was formed by photolithography, and then a conductor circuit layer was formed by electrolytic copper plating. The multilayer circuit formation process was then repeated to form a build-up multilayer circuit on both surfaces of the glass plate (glass core).

[0122] Furthermore, a solder resist layer was formed on the outermost layer of the multilayer circuit, and the external connection terminals were exposed by photolithography. After plating, solder balls were formed. The process of forming the solder balls involved the highest heat treatment temperature of the series of processes, at approximately 320°C. Finally, the glass plate with the solder balls formed was diced to obtain a high-frequency device. [Example]

[0123] Glass batches having the glass compositions of Sample No. 19 in Table 3 and Sample No. 72 in Table 9 were melted in a test melting furnace to obtain molten glass, which was then formed into glass plates with a thickness of 5.1 mm using the float process. The resulting glass plates were then cut to obtain rectangular glass plates measuring 350 mm x 450 mm. These glass plates were then polished to a thickness of 5.0 mm. The arithmetic mean roughness Ra of the polished glass was measured using a stylus surface roughness meter and found to be 500 nm. Next, multiple through holes were formed in the rectangular glass plate. The through holes were created by irradiating the surface of the glass plate with a commercially available picosecond laser to form a modified layer, which was then removed by etching.

[0124] Next, high-frequency devices were fabricated using the glass plates of Sample No. 19 in Table 3 and Sample No. 72 in Table 9. First, a conductor circuit layer was formed in the through holes of the glass plate by a semi-additive method. Specifically, the conductor circuit layer was formed by sequentially fabricating a seed metal layer by sputtering, forming a metal layer by electroless plating, forming a resist pattern, and forming copper plating for wiring.

[0125] Next, capacitors, coils, etc. were provided on both surfaces of the glass plate, and then an insulating resin layer was formed to create via holes. This was followed by a desmearing process and electroless copper plating, followed by the formation of a dry film resist layer. A resist pattern was formed by photolithography, and then a conductor circuit layer was formed by electrolytic copper plating. The multilayer circuit formation process was then repeated, resulting in a build-up multilayer circuit on both surfaces of the glass plate (glass core). No peeling of the circuit layer occurred during this process.

[0126] Furthermore, a solder resist layer was formed on the outermost layer of the multilayer circuit, and the external connection terminals were exposed by photolithography. After plating, solder balls were formed. The process of forming the solder balls involved the highest heat treatment temperature of the series of processes, at approximately 320°C. Finally, the glass plate with the solder balls formed was diced to obtain a high-frequency device. [Industrial Applicability]

[0127] The glass plate of the present invention is suitable for use in high-frequency devices, but is also suitable as a substrate for printed wiring boards, glass antennas, micro LEDs, and glass interposers, which require low dielectric properties.The glass plate of the present invention is also suitable as a component for constituting a resonator in a dielectric filter such as a duplexer.

Claims

1. The glass composition is, in mass%, SiO ２ 50-72%, Al ２ O ３ 0-22%, B ２ O ３ 22-38%, Li ２ O + Na ２ O+K ２ The mass ratio (SrO+BaO) / (MgO+CaO) is 0.3 or less, and B ２ O ３ -Al ２ O ３ The relative dielectric constant at 25°C and a frequency of 10 GHz is 4.9 or less, and the β-OH value is 1.1 mm －１ is as follows: The glass plate is characterized in that the β-OH value is a value calculated by the following formula. β-OH value = (1 / X) log (T １ / T ２ ) X: Plate thickness (mm) T １ :Reference wavelength 3846cm －１ Transmittance (%) at T ２ : Hydroxyl group absorption wavelength 3600 cm －１ Minimum transmittance (%) in the vicinity

2. The glass composition is, in mass%, SiO ２ 50-72%, Al ２ O ３ 0-22%, B ２ O ３ 22-38%, Li ２ O + Na ２ O+K ２ The mass ratio (SrO+BaO) / (MgO+CaO) is 0.3 or less, and B ２ O ３ -Al ２ O ３ The relative dielectric constant at 25°C and a frequency of 2.45 GHz is 4.9 or less, and the β-OH value is 1.1 mm －１ is as follows: The glass plate is characterized in that the β-OH value is a value calculated by the following formula. β-OH value = (1 / X) log (T １ / T ２ ) X: Plate thickness (mm) T １ :Reference wavelength 3846cm －１ Transmittance (%) at T ２ : Hydroxyl group absorption wavelength 3600 cm －１ Minimum transmittance (%) in the vicinity

3. The glass composition is, in mass%, SiO ２ 50-72%, Al ２ O ３ 0-22%, B ２ O ３ 22-38%, Li ２ O + Na ２ O+K ２ The mass ratio (SrO+BaO) / (MgO+CaO) is 0.3 or less, and B ２ O ３ -Al ２ O ３ is 4 mass% or more, and the β-OH value is 1.1 mm －１ is as follows: The glass plate is characterized in that the β-OH value is a value calculated by the following formula. β-OH value = (1 / X) log (T １ / T ２ ) X: Plate thickness (mm) T １ :Reference wavelength 3846cm －１ Transmittance (%) at T ２ : Hydroxyl group absorption wavelength 3600 cm －１ Minimum transmittance (%) in the vicinity

4. Mass ratio (MgO+CaO+SrO+BaO) / (SiO ２ +Al ２ O ３ +B ２ O ３ 4. The glass plate according to claim 1, wherein the value of (a) is 0.001 to 0.

4.

5. 5. The glass plate according to claim 1, wherein a plurality of through holes are formed in the plate thickness direction.

6. 6. The glass plate according to claim 5, wherein the through holes have an average inner diameter of 300 μm or less.

7. 7. The glass plate according to claim 5, wherein the difference between the maximum and minimum inner diameters of the through holes is 50 [mu]m or less.

8. 8. The glass plate according to claim 5, wherein the maximum length of cracks extending from the through holes in the surface direction is 100 μm or less.

9. 9. The glass plate according to claim 1, wherein the dielectric loss tangent at 25° C. and a frequency of 10 GHz is 0.01 or less.

10. 10. The glass plate according to claim 1, wherein the glass plate has a Young's modulus of 40 GPa or more.

11. 11. The glass plate according to claim 1, wherein the glass plate has a thermal shrinkage of 30 ppm or less when heated at a rate of 5°C / min, held at 500°C for 1 hour, and cooled at a rate of 5°C / min.

12. The thermal expansion coefficient in the temperature range of 30 to 380°C is 20 x 10 -７ ~50 x 10 -７ 12. The glass plate according to claim 1, wherein the glass plate has a viscosity of 1000 MPa or more.

13. The difference between the thermal expansion coefficient in the temperature range of 20 to 300°C and the thermal expansion coefficient in the temperature range of 20 to 200°C is 1.0 x 10 -７ 13. The glass plate according to claim 1, wherein the glass plate has a melting point of 1 / °C or less.

14. 14. The glass plate according to claim 1, wherein the external transmittance at a wavelength of 355 nm is 80% or more when measured at a thickness of 1.0 mm.

15. 15. The glass plate according to claim 1, wherein the external transmittance at a wavelength of 265 nm is 15% or more when the thickness is 1.0 mm.

16. Liquidus viscosity is 10 ４．０ The glass plate according to any one of claims 1 to 15, characterized in that it has a viscosity of dPa·s or more.

17. 17. The glass plate according to claim 1, which is formed by an overflow downdraw method.

18. Mass ratio (SrO+BaO) / B ２ O ３ 18. The glass plate according to claim 1, wherein the σ is 0.03 or less.

19. B ２ O ３ The glass plate according to any one of claims 1 to 18, characterized in that -(MgO+CaO+SrO+BaO) is 10 mass % or more.

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