Glass and Method for Measuring Dielectric Properties Using the Same

Abstract

A glass according to the present invention is characterized by having: a measurement frequency of 2.45 GHz after performing a constant temperature and humidity test under a temperature of 85 °C and a relative humidity of 85% for 1000 hours; and a rate of change of dielectric loss tangent at a measurement temperature of 25 °C of at most 30%.

Description

[Technical Field]

[0001] The present invention relates to glass and a method for measuring dielectric properties using the same, and more specifically to glass used as a measurement standard material (dielectric constant standard material) when measuring dielectric properties at frequencies in the band used in fifth-generation mobile communication systems (5G), and a method for measuring dielectric properties using the same. [Background technology]

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

[0003] The frequencies expected to be used in fifth-generation mobile communication systems (5G) include 3.7GHz, 4.5GHz, 28GHz, and 39GHz. Generally, the higher the frequency, the greater the dielectric loss of the electrical signal propagating through the system. On the other hand, it is possible to reduce the dielectric loss of the electrical signal by lowering the relative permittivity and dielectric loss tangent of the surrounding constituent materials through which the electrical signal propagates (see Non-Patent Literature 1). Therefore, it is desirable to reduce the dielectric properties of the constituent materials.

[0004] Incidentally, methods for measuring dielectric properties include, for example, the cavity resonator method and the balanced disk resonator method (see Non-Patent Documents 2 and 3). Furthermore, readily available materials such as Teflon and alumina are commonly used as measurement standards when measuring dielectric properties.

[0005] Non-patent documents 4 and 5 describe a supply plan for dielectric constant standards used when measuring the dielectric properties of constituent materials in the high-frequency range. Non-patent document 4 specifies that quartz glass and alkali-free glass will be used as candidate measurement standard materials. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Journal of the Institute of Electronics Engineers of Japan, Vol. 22, No. 2 (2019), P. 172, Line Loss, Arisan Tokui [Non-Patent Document 2] Metal, Vol. 89, No. 2 (2019), P. 42 (144), Evaluation of Dielectric Characteristics and Radio Wave Absorption Characteristics, Daisuke Ikimi [Non-Patent Document 3] Homepage of Sumitomo Research Corporation, 1630560467110_0.htm, Search Date: December 3, 2019 [Non-Patent Document 4] Seminar Text of the Technical Information Association, Low Dielectric Constant, Low Dissipation Factor of High-Frequency Compatible Substrate Materials and Reduction of Transmission Loss, Date of Lecture: October 22, 2018, Dielectric Constant Measurement Technology of High-Frequency Substrate Materials and Its Applications, Mr. Yuto Kato, Presentation Materials, P. 16 [Non-Patent Document 5] Measurement Standard Preparation Plan (Physical Standard), 1630560467110_1.pdf, Search Date: December 3, 2019 [Disclosure of the Invention] [Problems to be Solved by the Invention]

[0007] As described above, Teflon and alumina are used as measurement standard substances, but they have hygroscopicity. Also, it is known that the dielectric characteristics in the high-frequency range change depending on moisture. Therefore, when Teflon or alumina is used as a measurement standard substance, the reliability of the measured values of dielectric characteristics deteriorates.

[0008] In addition, since the supply amount of quartz glass is small compared to other glasses and it is expensive, it is presumed to be difficult to use as a measurement standard substance. Alkali-free glass generally does not have the low dielectric characteristics required for the fifth-generation mobile communication system (5G) and is unsuitable as a measurement standard substance for dielectric characteristics.

[0009] Furthermore, glasses with low dielectric characteristics generally have a high content of B2O3 in their composition, so they tend to have low moisture resistance.

[0010] This invention has been made in view of the above circumstances, and its technical objective is to provide a glass that has low dielectric properties while also having high moisture resistance, and a method for measuring dielectric properties using the same. [Means for solving the problem]

[0011] The inventors, after conducting various experiments, have discovered a glass whose dielectric properties do not easily change in tests such as temperature and humidity steady-state tests and high-temperature, high-humidity steady-state tests (unsaturated pressurized water vapor), and propose this as the present invention. Specifically, the glass of the present invention is characterized in that the rate of change of the dielectric loss tangent at a measurement frequency of 2.45 GHz and a measurement temperature of 25°C after a temperature and humidity steady-state test of 1000 hours at a temperature of 85°C, relative humidity of 85%, is 30% or less. Here, "glass" as used in the present invention includes not only amorphous glass but also crystallized glass. Furthermore, the dielectric loss tangent at a measurement frequency of 2.45 GHz and a measurement temperature of 25°C can be measured, for example, by the well-known cavity resonator method. The rate of change of the dielectric loss tangent refers to the value calculated as [(dielectric loss tangent after test - dielectric loss tangent before test) / (dielectric loss tangent after test)] × 100.

[0012] Furthermore, it is preferable that the glass of the present invention exhibits a change rate of 30% or less in the dielectric loss tangent at a measurement frequency of 2.45 GHz and a measurement temperature of 25°C after undergoing a high-temperature, high-humidity steady-state test (JIS-C0096-2001) at a temperature of 120°C, a relative humidity of 85%, and for 12 hours. For the above high-temperature, high-humidity steady-state test, for example, an unsaturated high-speed life tester PC-242HSR2 manufactured by Hirayama Seisakusho Co., Ltd. can be used as the test apparatus.

[0013] Furthermore, it is preferable that the glass of the present invention, after undergoing a high-temperature, high-humidity steady-state test (JIS-C0096-2001) at a temperature of 120°C, relative humidity of 85%, for 48 hours, has a boron X-ray intensity that decreases by 50% at a depth of 5 μm or less, based on a depth of 15 μm. The "depth at which boron decreases" is determined by point analysis of the characteristic X-ray intensity value (unit: Count) of the boron element's Kα rays when elemental analysis is performed on a fractured glass surface as an analytical sample, moving from the outermost surface of the glass towards the depth. For the outermost surface, i.e., depth 0 μm, if the fracture surface is measured, the beam diameter of the irradiated X-rays does not irradiate the fracture surface; therefore, the measurement value of the outermost surface of the glass side was used as the boron X-ray intensity at a depth of 0 μm. The boron X-ray intensity can be analyzed using, for example, an EPMA (Electron Probe Micro Analyzer, EPMA-1720, Shimadzu Corporation).

[0014] Furthermore, it is preferable that the glass of the present invention has a product of the content of B2O3-Al2O3 (mol%) and the content of B2O3-(MgO+CaO+SrO+BaO) (mol%) of 260 or less. This significantly improves moisture resistance. Note that "B2O3-Al2O3" is obtained by subtracting the content of Al2O3 from the content of B2O3. "B2O3-(MgO+CaO+SrO+BaO)" is obtained by subtracting the combined amounts of MgO, CaO, SrO, and BaO from the content of B2O3. By increasing the amount of Al2O3 from B2O3 and increasing the amount of alkaline earth elements from B2O3, phase separation of the glass, i.e., separation into a phase with a lot of B2O3 and a phase with a little B2O3, can be suppressed. As a result, the decrease in B2O3 due to weathering tests can be suppressed.

[0015] Furthermore, the glass of the present invention is preferably crystallized glass. This enhances its moisture resistance.

[0016] Furthermore, the glass of the present invention preferably contains, in molar percentages, SiO2 60-75%, Al2O 30-15%, B2O 38-28%, Li2O+Na2O+K2O 0-3%, and MgO+CaO+SrO+BaO 0-14%, and has a relative permittivity of 6 or less at 25°C and a frequency of 2.45 GHz. In this way, a glass with low dielectric properties and high moisture resistance can be obtained.

[0017] Furthermore, the glass of the present invention preferably contains, in molar percentage, SiO2 75-85%, Al2O 30-5%, B2O3 10-20%, Li2O 0-5%, Na2O 1-10%, K2O 0-5%, and Li2O+Na2O+K2O 3-10%, and has a relative permittivity of 6 or less at 25°C and a frequency of 2.45 GHz. In this way, a glass with low dielectric properties and high moisture resistance can be obtained.

[0018] Furthermore, the glass of the present invention preferably contains, in molar percentages, SiO2 55-75%, Al2O3 10-20%, Li2O 2% or more, TiO2 0.5-3%, TiO2 + ZrO2 2-5%, and SnO2 0.1-0.5%, and has a relative permittivity of 7 or less at 25°C and a frequency of 2.45 GHz. In this way, a glass with low dielectric properties and high moisture resistance can be obtained.

[0019] Furthermore, the glass of the present invention is preferably used as a measurement standard material when measuring dielectric properties.

[0020] The present invention provides a method for measuring dielectric properties using a measurement standard material, characterized in that the measurement standard material is the glass described above. In this way, dielectric properties can be measured stably over a long period of time. Furthermore, in the dielectric properties measurement method of the present invention, it is preferable to heat-treat the measurement standard material to a temperature above the annealing point of glass before measuring the dielectric properties. This allows the dielectric properties of the measurement standard material to be restored to their initial state if they have changed. [Brief explanation of the drawing]

[0021] [Figure 1] This graph shows the results of the boron composition analysis of glass cross-sections for samples No. 7 and 25 in the section for Example 3. [Figure 2] This graph shows the effect of changes in the composition of the glass surface on the dielectric loss tangent for samples No. 7, 25, and 26 in the section for Example 3. [Figure 3] The reflectance spectra of samples No. 7, 25, and 26 in the section for Example 3 are shown below. (a) is the reflectance spectrum of sample No. 7, (b) is the reflectance spectrum of sample No. 25, and (c) is the reflectance spectrum of sample No. 26. [Figure 4] The transmittance spectra for samples No. 7, 25, and 26 in the section for Example 3 are shown below: (a) is the transmittance spectrum of sample No. 7, (b) is the transmittance spectrum of sample No. 25, and (c) is the transmittance spectrum of sample No. 26. [Figure 5] This graph shows the changes in β-OH values ​​for samples No. 7, 25, and 26 in the section for Example 3. [Figure 6] The graphs in the section for Example 3 show the relationship between the dielectric loss tangent and the β-OH value at 25°C and a frequency of 2.45GHz for samples No. 7, 25, and 26. (a) shows the relationship between the dielectric loss tangent and the β-OH value at 25°C and a frequency of 2.45GHz for sample No. 7, (b) shows the relationship between the dielectric loss tangent and the β-OH value at 25°C and a frequency of 2.45GHz for sample No. 25, and (c) shows the relationship between the dielectric loss tangent and the β-OH value at 25°C and a frequency of 2.45GHz for sample No. 26. [Modes for carrying out the invention]

[0022] In the glass of the present invention, the rate of change of the dielectric loss tangent at a measurement frequency of 2.45 GHz and a measurement temperature of 25°C, after a steady-state temperature and humidity test at a temperature of 85°C, relative humidity of 85%, for 1000 hours, is preferably 30% or less, 29% or less, 28% or less, 27% or less, 26% or less, 25% or less, 24% or less, 23% or less, 22% or less, 21% or less, 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, and especially 1% or less. If the rate of change of the dielectric loss tangent is too high, the moisture resistance of the glass tends to decrease, making it difficult to apply to high-frequency devices and the like.

[0023] In the glass of the present invention, the rate of change of the dielectric loss tangent at a measurement frequency of 2.45 GHz and a measurement temperature of 25°C after a high-temperature, high-humidity steady-state test (JIS-C0096-2001) at a temperature of 120°C, relative humidity of 85%, for 12 hours is preferably 30% or less, 29% or less, 28% or less, 27% or less, 26% or less, 25% or less, 24% or less, 23% or less, 22% or less, 21% or less, 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, and especially 1% or less. If the rate of change of the dielectric loss tangent is too high, the moisture resistance of the glass tends to decrease, making it difficult to apply to high-frequency devices and the like.

[0024] In the glass of the present invention, the rate of change of the dielectric loss tangent at a measurement frequency of 2.45 GHz and a measurement temperature of 25°C after a high-temperature, high-humidity steady-state test (JIS-C0096-2001) at a temperature of 120°C, relative humidity of 85%, and for 48 hours is preferably 30% or less, 29% or less, 28% or less, 27% or less, 26% or less, 25% or less, 24% or less, 23% or less, 22% or less, 21% or less, 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, and especially 1% or less. If the rate of change of the dielectric loss tangent is too high, the moisture resistance of the glass tends to decrease, making it difficult to apply to high-frequency devices and the like.

[0025] In the glass of the present invention, after performing a high-temperature, high-humidity steady-state test (JIS-C0096-2001) at a temperature of 120°C, relative humidity of 85%, for 48 hours, the X-ray intensity of boron analyzed in the depth direction from the outermost surface decreases by 50% at a depth of 15 μm, preferably at depths of 5.0 μm or less, 4.9 μm or less, 4.8 μm or less, 4.7 μm or less, 4.6 μm or less, 4.5 μm or less, 4.4 μm or less, 4.3 μm or less, 4.2 μm or less, 4.1 μm or less, 4.0 μm or less, 3.9 μm or less, 3.8 μm or less, 3.7 μm or less, 3.6 μm or less, 3.5 μm or less, 3.4 μm or less, 3.3 μm or less, 3. The sizes are 2 μm or less, 3.1 μm or less, 3.0 μm or less, 2.9 μm or less, 2.8 μm or less, 2.7 μm or less, 2.6 μm or less, 2.5 μm or less, 2.4 μm or less, 2.3 μm or less, 2.2 μm or less, 2.1 μm or less, 2.0 μm or less, 1.9 μm or less, 1.8 μm or less, 1.7 μm or less, 1.6 μm or less, 1.5 μm or less, 1.4 μm or less, 1.3 μm or less, 1.2 μm or less, 1.1 μm or less, 1.0 μm or less, 0.9 μm or less, 0.8 μm or less, 0.7 μm or less, 0.6 μm or less, 0.5 μm or less, 0.4 μm or less, 0.3 μm or less, 0.2 μm or less, 0.1 μm or less, and 0.0 μm or less. If the boron reduction depth at this time is too great, the moisture resistance of the glass tends to decrease, making it difficult to apply to high-frequency devices and the like.

[0026] In the glass of the present invention, after performing a high-temperature, high-humidity steady-state test (JIS-C0096-2001) at a temperature of 120°C, relative humidity of 85%, for 48 hours, the glass was held at a temperature of +30°C above its annealing point for 3 hours, and then cooled to room temperature at -3°C / min. The X-ray intensity of boron, analyzed in the depth direction from the outermost surface, decreased by 50% at a depth of 15 μm, is preferably 10.0 μm or less, 9.0 μm or less, 8.0 μm or less, 7.0 μm or less, 6.0 μm or less, 5.0 μm or less, 4.9 μm or less, 4.8 μm or less, 4.7 μm or less, 4.6 μm or less, 4.5 μm or less, 4.4 μm or less, 4.3 μm or less, 4.2 μm or less, 4.1 μm or less, 4.0 μm or less, 3.9 μm or less, 3.8 μm or less, and 3. .7μm or less, 3.6μm or less, 3.5μm or less, 3.4μm or less, 3.3μm or less, 3.2μm or less, 3.1μm or less, 3.0μm or less, 2.9μm or less, 2.8μm Below, 2.7μm or less, 2.6μm or less, 2.5μm or less, 2.4μm or less, 2.3μm or less, 2.2μm or less, 2.1μm or less, 2.0μm or less, 1.9μm or less, 1. The possible depths are 8 μm or less, 1.7 μm or less, 1.6 μm or less, 1.5 μm or less, 1.4 μm or less, 1.3 μm or less, 1.2 μm or less, 1.1 μm or less, 1.0 μm or less, 0.9 μm or less, 0.8 μm or less, 0.7 μm or less, 0.6 μm or less, 0.5 μm or less, 0.4 μm or less, 0.3 μm or less, 0.2 μm or less, 0.1 μm or less, and 0.0 μm or less. If the boron reduction depth at this time is too large, the moisture resistance of the glass tends to decrease, making it difficult to apply to high-frequency devices, etc.

[0027] The glass of the present invention can have various compositions, but among them, it is preferable to have the compositions described below (Glass A to C). The glass of the present invention (Glass A) preferably contains, in mol% terms, SiO2 60-75%, Al2O 30-15%, B2O 38-28%, Li2O+Na2O+K2O 0-3%, and MgO+CaO+SrO+BaO 0-14%. The reasons for limiting the content of each component as described above are shown below. Note that the following % indications refer to mol% unless otherwise specified.

[0028] The SiO2 content is preferably 60-75%, 61-74%, 62-72%, 63-71%, 64-70%, 64-69.5%, 64-69%, and particularly 65-67%. If the SiO2 content is too low, the dielectric constant, dielectric loss tangent, and density tend to be high. Also, the moisture resistance tends to decrease. On the other hand, if the SiO2 content is too high, the high-temperature viscosity increases, reducing meltability, and devitrified crystals such as cristobalite tend to precipitate during molding.

[0029] Al2O3 is a component that increases Young's modulus and suppresses phase separation. Furthermore, it is a component that significantly improves moisture resistance. Therefore, the lower limit range of Al2O3 is preferably 0% or more, 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 especially 6% or more. On the other hand, if the Al2O3 content is too high, the liquidus temperature will rise, and the devitrification resistance will tend to decrease. Also, the relative permittivity and dielectric loss tangent tend to increase. Therefore, the upper limit range for Al2O3 is preferably 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 especially 7.0% or less.

[0030] B2O3 is a component that reduces the dielectric constant and dielectric loss tangent, but it also reduces Young's modulus and density. It is also a component that reduces moisture resistance. However, if the B2O3 content is too low, it becomes difficult to ensure low dielectric properties, and its function as a flux becomes insufficient, leading to high-temperature viscosity and a decrease in foam quality. Furthermore, it becomes difficult to achieve low density. Therefore, the lower limit range for B2O3 is preferably 8% or more, 9% or more, 10% or more, 15% or more, 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%, and especially 22% or more. On the other hand, if the B2O3 content is too high, heat resistance and chemical durability tend to decrease, and moisture resistance tends to decrease due to phase separation. Therefore, the upper limit range for B2O3 is preferably 28% or less, 27% or less, 26% or less, 25% or less, 24% or less, and especially 23% 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 especially 10% or more. If the B2O3-Al2O3 content is too low, it becomes difficult to ensure low dielectric properties.

[0032] Alkali metal oxides are components that enhance melting and moldability, but if their content is too high, the density increases, moisture resistance decreases, the coefficient of thermal expansion becomes unreasonably high, thermal shock resistance decreases, and it becomes difficult to match the coefficient of thermal expansion of surrounding materials. Therefore, the content of Li2O + Na2O + K2O (total amount of Li2O, Na2O, and K2O) is preferably 0-3%, 0-2%, 0-1%, 0-0.5%, 0-0.2%, 0-0.1%, and especially less than 0.001-0.05%. The individual contents of Li2O, Na2O, and K2O are preferably 0-3%, 0-2%, 0-1%, 0-0.5%, 0-0.2%, 0-0.1%, and especially less than 0.001-0.01%.

[0033] Alkaline earth metal oxides are components that lower the liquidus temperature, making it difficult for devitrified crystals to form in the glass, and also enhance meltability and moldability. The content of MgO+CaO+SrO+BaO (total amount of MgO, CaO, SrO, and BaO) is preferably 0-14%, 0-12%, 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, the devitrification resistance tends to decrease, and it cannot fully exert its function as a flux, leading to a decrease in meltability. On the other hand, if the content of MgO+CaO+SrO+BaO is too high, the density increases, making it difficult to lighten the glass, and the coefficient of thermal expansion becomes unduly high, leading to a decrease in thermal shock resistance.

[0034] MgO is a component that lowers high-temperature viscosity and improves meltability without reducing the strain point, and is also the component that is least likely to increase density among alkaline earth metal oxides. Furthermore, among alkaline earth metals, it is a component that particularly improves moisture resistance. The MgO content is preferably 0-12%, 0-10%, 0.01-8%, 0.1-6%, 0.2-5%, 0.3-4%, 0.5-3%, and especially 0.8-2%. However, if the MgO content is too high, the liquidus temperature rises, and the devitrification resistance tends to decrease. Also, the glass tends to split into phases, and the transparency tends to decrease.

[0035] CaO is a component that significantly increases meltability by lowering high-temperature viscosity without reducing the strain point, and is also a component that greatly enhances devitrification resistance in the composition system of glass A. It is also a component that enhances moisture resistance among alkaline earth metals. Therefore, the suitable lower limit range for 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 especially 2% or more. On the other hand, if the CaO content is too high, the coefficient of thermal expansion and density may increase unduly, or the balance of components in the composition may be disrupted, which can actually decrease devitrification resistance. Therefore, the suitable upper limit range for 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 especially 3% or less.

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

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

[0038] If the molar ratio (MgO+CaO+SrO+BaO) / (SiO2+Al2O3+B2O3) is too high, moisture resistance tends to decrease, and when forming through-holes by etching, the etching rate becomes faster, and the shape of the through-holes tends to become distorted. Furthermore, when forming through-holes by laser irradiation, the accuracy of hole drilling tends to decrease. On the other hand, if the molar ratio (MgO+CaO+SrO+BaO) / (SiO2+Al2O3+B2O3) is too low, the high-temperature viscosity increases, and the melting temperature rises, which tends to increase the manufacturing cost of glass plates. Therefore, the molar ratio (MgO+CaO+SrO+BaO) / (SiO2+Al2O3+B2O3) is preferably 0.001~0.4, 0.005~0.35, 0.010~0.30, 0.020~0.25, 0.030~0.20, 0.035~0.15, 0.040~0.14, 0.045~0.13, and particularly 0.050~0.10. Note that "(molar 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 molar ratio (MgO+CaO+SrO+BaO) / Al2O3 is too small, the resistance to devitrification decreases, making it difficult to form into a plate shape using the overflow down-draw method. On the other hand, if the molar ratio (MgO+CaO+SrO+BaO) / Al2O3 is too large, there is a risk that the density and thermal expansion coefficient will increase unduly. Therefore, the molar ratio (MgO+CaO+SrO+BaO) / Al2O3 is preferably 0.1~2.0, 0.1~1.5, 0.1~1.2, 0.2~1.2, 0.3~1.2, 0.4~1.1, and especially 0.5~1.0. 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 molar ratio (SrO+BaO) / B2O3 is preferably 1.0 or less, 0.5 or less, 0.2 or less, 0.1 or less, 0.05 or less, 0.03 or less, and particularly 0.02 or less. If the molar ratio (SrO+BaO) / B2O3 is too high, it becomes difficult to ensure low dielectric properties and difficult to increase the liquid phase viscosity. Note that "SrO+BaO" is the total amount of SrO and BaO. Also, "(SrO+BaO) / B2O3" refers to the value obtained by dividing the SrO+BaO content by the B2O3 content.

[0041] The B2O3-(MgO+CaO+SrO+BaO) content is preferably -5% or more, 0% or more, 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, 10% or more, 11% or more, and especially 12% or more. If the B2O3-(MgO+CaO+SrO+BaO) content is too low, it becomes difficult to ensure low dielectric properties, the density tends to increase, and the Young's modulus tends to decrease.

[0042] The molar ratio (SrO+BaO) / (MgO+CaO) is preferably 400 or less, 300 or less, 100 or less, 50 or less, 10 or less, 5 or less, 2 or less, 1 or less, 0.8 or less, 0.5 or less, and particularly 0.3 or less. If the molar ratio (SrO+BaO) / (MgO+CaO) is too large, it becomes difficult to ensure low dielectric properties and the density tends to increase.

[0043] The product of the content of B2O3-Al2O3 (mol%) and the content of B2O3-(MgO+CaO+SrO+BaO) (mol%) is preferably 600 or less, 550 or less, 500 or less, 450 or less, 400 or less, 350 or less, 340 or less, 330 or less, 320 or less, 310 or less, 300 or less, 290 or less, 280 or less, 270 or less, and especially 260 or less. If the product of the content of B2O3-Al2O3 and the content of B2O3-(MgO+CaO+SrO+BaO) is too large, it becomes difficult to ensure moisture resistance and the Young's modulus tends to decrease. Furthermore, the product of the B2O3-Al2O3 content and the B2O3-(MgO+CaO+SrO+BaO) content is preferably 1 or more, 5 or more, 10 or more, 20 or more, 30 or more, 40 or more, 50 or more, 60 or more, 70 or more, 80 or more, 90 or more, and especially 100 or more. If the product of the B2O3-Al2O3 content and the B2O3-(MgO+CaO+SrO+BaO) content is too small, it becomes difficult to ensure low dielectric properties and the coefficient of thermal expansion tends to decrease.

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

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

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

[0047] TiO2 is a component that lowers high-temperature viscosity and increases meltability, as well as suppressing solarization. However, if it is included in large quantities in the composition, the glass tends to become discolored and its transmittance decreases. Therefore, the TiO2 content is preferably 0-5%, 0-3%, 0-1%, 0-0.1%, and particularly 0-0.02%.

[0048] P2O5 is a component that enhances resistance to devitrification, but if it is included in large quantities in the composition, the glass may undergo phase separation and become prone to milky whitening, and the moisture resistance may be significantly reduced. Therefore, the P2O5 content is preferably 0-5%, 0-1%, 0-0.5%, and particularly 0-0.1%.

[0049] SnO2 is a component that exhibits good clarification properties in the high-temperature range, as well as a component that reduces high-temperature viscosity. The SnO2 content is preferably 0-1%, 0.01-0.5%, 0.05-0.3%, and particularly 0.07-0.2%. If the SnO2 content is too high, devitrified SnO2 crystals tend to precipitate in the glass.

[0050] Fe2O3 is a component that can be introduced as an impurity component or a clarifying agent component. However, if the Fe2O3 content is too high, the ultraviolet transmittance may decrease. 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 this invention includes divalent iron oxide and trivalent iron oxide, and divalent iron oxide shall be treated as equivalent to Fe2O3. Other polyvalent oxides shall also be treated in the same manner, based on the oxide indicated.

[0051] As a clarifying agent, the addition of SnO2 is preferable, but as long as the glass properties are not impaired, CeO2, SO3, C, and metal powders (e.g., Al, Si, etc.) may be added in amounts up to 1%.

[0052] As2O3, Sb2O3, F, and Cl also act effectively as clarifying agents, and the present invention does not exclude the inclusion of these components. However, from an environmental standpoint, 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 (glass B) of the present invention preferably contains, in molar percentage, SiO2 75-85%, Al2O 30-5%, B2O 310-20%, Li2O 0-5%, Na2O 1-10%, K2O 0-5%, and Li2O+Na2O+K2O 3-10%. The reasons for limiting the content of each component as described above are shown below. Note that the following percentages refer to molar percentages unless otherwise specified.

[0054] SiO2 is the main component that forms the glass skeleton structure. The SiO2 content is preferably 75-85%, 77-84%, 78-83%, 77-82%, and particularly 77-81%. If the SiO2 content is too low, the dielectric constant, dielectric loss tangent, and density tend to be high. Also, the moisture resistance tends to decrease. On the other hand, if the SiO2 content is too high, the high-temperature viscosity increases, reducing meltability, and devitrified crystals such as cristobalite tend to precipitate during molding.

[0055] Al2O3 is a component that enhances chemical durability, mechanical strength, and devitrification resistance. The Al2O3 content is preferably 0-5%, 1-4%, 1.1-3%, and particularly 2-3%. If the Al2O3 content is too high, the high-temperature viscosity increases, and meltability and moldability tend to decrease.

[0056] B2O3 is a component that forms a glass skeletal structure and reduces high-temperature viscosity. The B2O3 content is preferably 10-20%, 10-18%, 11-15%, and particularly 12-15%. If the B2O3 content is too high, the glass is more prone to phase separation, and once phase separation occurs, the thermal expansion coefficient and dielectric properties become non-uniform, and chemical durability tends to decrease. In addition, the amount of component evaporation from the molten glass increases, making it easier for a heterogeneous layer to form on the surface of the molten glass, and thus reducing the homogeneity of the glass. On the other hand, if the B2O3 content is too low, the viscosity of the glass becomes too high, and it becomes difficult to maintain low dielectric properties.

[0057] Alkali metal oxides are components that reduce the viscosity of glass and increase its meltability, while simultaneously increasing its thermal expansion coefficient and dielectric properties. The content of Li2O+Na2O+K2O is preferably 3-10%, 3.5-8%, and particularly 4-5%. If the content of Li2O+Na2O+K2O is too low, the viscosity of the glass will increase, and its meltability will tend to decrease. On the other hand, if the content of Li2O+Na2O+K2O is too high, the thermal expansion coefficient and dielectric properties will increase, and its thermal shock resistance will tend to decrease.

[0058] Li2O is a component that reduces high-temperature viscosity and increases melting properties. The Li2O content is preferably 0-5%, 0-3%, and particularly 0-1%. If the Li2O content is too high, the coefficient of thermal expansion becomes too high, which tends to reduce thermal shock resistance. Also, the dielectric properties become too high.

[0059] Na2O is a component that reduces high-temperature viscosity and increases meltable properties. The Na2O content is preferably 1-10%, 2-7%, 3-6.5%, and particularly 4-6%. If the Na2O content is too low, the high-temperature viscosity will increase, and meltable properties will tend to decrease. On the other hand, if the Na2O content is too high, the thermal expansion coefficient and dielectric properties will become too high.

[0060] K2O is a component that reduces high-temperature viscosity and increases melting properties. The K2O content is preferably 0-5%, 0-3%, and particularly 0-1%. If the K2O content is too high, the coefficient of thermal expansion becomes too high, which tends to reduce thermal shock resistance. Also, the dielectric properties become too high.

[0061] In addition to the components listed above, other components may also be included. For example, MgO, CaO, SrO, BaO, ZnO, TiO2, ZrO2, SnO2, P2O5, Cr2O3, Sb2O3, SO2, Cl2, PbO, La2O3, WO3, Co3O4, Nb2O5, Y2O3, CeO2, etc. may be included to improve the coefficient of thermal expansion, dielectric properties, high-temperature viscosity, etc. It is preferable that the total content of these components be 3% or less.

[0062] Furthermore, trace components such as H2, CO2, CO, He, Ne, Ar, and N2 may be included in a total amount of up to 0.1%. In addition, noble metal elements such as Pt and Rh may be included in the glass in a total amount of up to 500 ppm, as long as they do not adversely affect the dielectric properties.

[0063] The glass (glass C) of the present invention is a crystallized glass, and preferably contains, in molar percentages, SiO2 55-75%, Al2O3 10-20%, Li2O 2% or more, TiO2 0.5-3%, TiO2 + ZrO2 2-5%, and SnO2 0.1-0.5%. The reasons for limiting the content of each component as described above are shown below. Note that the following percentages refer to molar percentages unless otherwise specified.

[0064] SiO2 forms the framework of glass and is a component of the Li2O-Al2O3-SiO2 crystal system. It is also a component that reduces dielectric properties. The SiO2 content is preferably 55-75%, 58-74%, 60-74%, and especially 65-73%. If the SiO2 content is too low, the coefficient of thermal expansion tends to increase, making it difficult to obtain glass containing crystals with excellent thermal shock resistance. It also tends to reduce chemical durability and moisture resistance. On the other hand, if the SiO2 content is too high, the meltability decreases, the viscosity of the glass increases, making it difficult to clarify and difficult to mold the glass.

[0065] Al2O3 forms the framework of the glass and is a component of the Li2O-Al2O3-SiO2 crystal system. Furthermore, its presence in the residual glass phase of crystallized glass can reduce the intensification of coloration of TiO2 and Fe2O3 due to SnO2. The Al2O3 content is preferably 10-20%, 11-18%, and particularly 12-17%. If the Al2O3 content is too low, the coefficient of thermal expansion tends to increase, making it difficult to obtain glass with excellent thermal shock resistance. Chemical durability and moisture resistance also tend to decrease. Moreover, the effect of reducing the intensification of coloration of TiO2 and Fe2O3 due to SnO2 becomes less pronounced. On the other hand, if the Al2O3 content is too high, meltability decreases, the viscosity of the glass increases, making clarification difficult and glass molding difficult. Additionally, mullite crystals tend to precipitate, causing devitrification of the glass and making it more prone to breakage.

[0066] Li2O is a component that makes up the Li2O-Al2O3-SiO2 system crystal, and it greatly affects the crystallinity of the glass, as well as reducing the viscosity of the glass and improving its meltability and moldability. The Li2O content is preferably 2% or more, 2.5% or more, 3% or more, 4% or more, 5% or more, and especially 6% or more. If the Li2O content is too low, mullite crystals tend to precipitate, causing the glass to devitrify. Also, when crystallizing the glass, it becomes difficult for the Li2O-Al2O3-SiO2 system crystals to precipitate, making it difficult to obtain glass with excellent thermal shock resistance. Furthermore, meltability tends to decrease, the viscosity of the glass increases, making it difficult to clarify and difficult to mold the glass. On the other hand, if the Li2O content is too high, the crystallinity becomes too strong, causing the glass to devitrify and making it more prone to breakage. It also becomes less hygroscopic. Therefore, the Li2O content is preferably 10% or less, 9.5% or less, and especially 9% or less.

[0067] TiO2 is a component that acts as a nucleating agent for crystal precipitation. The TiO2 content is preferably 0.5-3%, 0.8-2.3%, 1-2%, 1.1-1.9%, 1.2-1.8%, 1.3-1.7%, 1.5-1.7%, and especially preferably 1.6-1.7%. If the TiO2 content is too high, the color tends to become stronger. Also, the glass tends to devitrify and become more prone to breakage. On the other hand, if the TiO2 content is too low, crystal nuclei will not be sufficiently formed, and there is a risk that coarse crystals will precipitate, causing clouding or breakage.

[0068] In addition to the ingredients listed above, other ingredients such as those listed below can also be introduced.

[0069] MgO is a component that dissolves in Li2O-Al2O3-SiO2 crystals and has the effect of increasing the thermal expansion coefficient of the Li2O-Al2O3-SiO2 crystals. The MgO content is preferably 0-2%, 0.1-1.5%, 0.3-1.3%, and especially 0.5-1.2%. If the MgO content is too high, the crystallinity becomes too strong, making the glass more prone to breakage.

[0070] ZnO, like MgO, is a component that dissolves in Li2O-Al2O3-SiO2 crystal systems. The ZnO content is preferably 0-2%, 0-1.5%, and particularly preferably 0.1-1.2%. If the ZnO content is too high, the crystallinity becomes too strong, and the glass tends to devitrify when molded while cooling slowly. As a result, the glass becomes more fragile, making molding, for example, difficult using the float method.

[0071] The content of each component, SrO and CaO, is not particularly limited as long as it meets the above ranges, but for example, it is preferable to limit SrO to 0.5% or less, particularly 0.3% or less, and CaO to 0.2% or less, particularly 0.1% or less.

[0072] SnO2 acts as a clarifying agent. The preferred SnO2 content is 0.1-0.5%, 0.1-0.4%, and particularly 0.1-0.3%. If the SnO2 content is less than 0.1%, the clarifying effect becomes less pronounced. On the other hand, if the SnO2 content is too high, the coloration of TiO2 and Fe2O3 becomes too strong, causing the glass to easily take on a yellowish tint. It also becomes more prone to devitrification.

[0073] Fe2O3 is an impurity component that can be present. The Fe2O3 content is preferably 300 ppm or less, 250 ppm or less, and especially 200 ppm or less. A lower Fe2O3 content is preferable because it reduces discoloration; however, achieving a level below 60 ppm, for example, requires the use of high-purity raw materials, which tends to significantly increase glass manufacturing costs.

[0074] ZrO2, like TiO2, is a nucleating component for crystal precipitation during the crystallization process. The ZrO2 content is preferably 0-3%, 0.1-2.5%, and particularly preferably 0.5-2.3%. If the ZrO2 content is too high, the glass tends to devitrify during melting, making glass molding difficult.

[0075] The TiO2+ZrO2 content (total amount of TiO2 and ZrO2) is preferably 2-5%, 2.2-4.5%, and particularly preferably 2.3-3.8%. If the TiO2+ZrO2 content is within the above range, it is possible to obtain glass with the desired color tone and high transparency.

[0076] B2O3 is a component that promotes the dissolution of SiO2 raw materials in the melting process. The B2O3 content is preferably 0-2%, and particularly preferably less than 0-1%. Too much B2O3 tends to impair heat resistance and also reduces moisture resistance.

[0077] P2O5 is a component that promotes phase separation and aids in the formation of crystal nuclei. The P2O5 content is preferably 0-3%, 0.1-2%, and especially 0.2-1%. If the P2O5 content is too high, the glass is more likely to separate during the melting process, making it difficult to obtain glass with the desired composition, and the glass tends to become opaque.

[0078] Furthermore, to reduce the viscosity of the glass and improve its meltability and moldability, it is possible to add 0-2% of Na2O, K2O, and BaO in total, especially 0.1-2%, of the total amount. If the total amount of these components is too high, the glass will be prone to devitrification.

[0079] The glass of the present invention preferably has the following properties.

[0080] The relative permittivity at 25°C and a frequency of 10GHz is preferably 7.0 or less, 6.9 or less, 6.8 or less, 6.7 or less, 6.6 or less, 6.5 or less, 6.4 or less, 6.3 or less, 6.2 or less, 6.1 or less, 6.0 or less, 5.9 or less, 5.8 or less, 5.7 or less, 5.6 or less, 5.5 or less, 5.4 or less, 5.3 or less, 5.2 or less, 5.1 or less, 5.0 or less, 4.9 or less, 4.8 or less, 4.7 or less, 4.6 or less, and especially 4.5 or less. If the relative permittivity is too high, the transmission loss when an electrical signal is transmitted to a high-frequency device tends to increase.

[0081] At 25°C and a frequency of 10GHz, the dielectric loss tangent 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, and particularly 0.003 or less. If the dielectric loss tangent is too high, the transmission loss when an electrical signal is transmitted to a high-frequency device tends to increase.

[0082] The relative permittivity at 25°C and a frequency of 2.45 GHz is preferably 7.0 or less, 6.9 or less, 6.8 or less, 6.7 or less, 6.6 or less, 6.5 or less, 6.4 or less, 6.3 or less, 6.2 or less, 6.1 or less, 6.0 or less, 5.9 or less, 5.8 or less, 5.7 or less, 5.6 or less, 5.5 or less, 5.4 or less, 5.3 or less, 5.2 or less, 5.1 or less, 5.0 or less, 4.9 or less, 4.8 or less, 4.7 or less, 4.6 or less, particularly 4.5 or less. If the relative permittivity is too high, the transmission loss when an electrical signal is transmitted to a high-frequency device tends to increase.

[0083] 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 0.003 or less. If the dielectric loss tangent is too high, the transmission loss when an electrical signal is transmitted to a high-frequency device tends to increase.

[0084] The thermal expansion coefficient in the temperature range of 30 to 380°C is preferably 0×10 -7 ~60×10 -7 / °C, 10×10 -7 ~55×10 -7 / °C, 20×10 -7 ~50×10 -7 / °C, 22×10 -7 ~48×10 -7 / °C, 23×10 -7 ~47×10 -7 / °C, 25×10 -7 ~46×10 -7 / °C, 28×10 -7 ~45×10 -7 / °C, 30×10 -7 ~43×10 -7 / °C, 32×10 -7 ~41×10 -7 / °C, particularly 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 match the thermal expansion coefficients of various peripheral members.

[0085] The Young's modulus is preferably 40 GPa or higher, 41 GPa or higher, 43 GPa or higher, 45 GPa or higher, 47 GPa or higher, 50 GPa or higher, 51 GPa or higher, 52 GPa or higher, 53 GPa or higher, 54 GPa or higher, and especially 55 GPa or higher. If the Young's modulus is too low, the glass will bend easily, which can easily lead to wiring defects during the fabrication of high-frequency devices.

[0086] The refractive index nd (measurement wavelength 587.6 nm) is preferably 1.55 or less, 1.54 or less, 1.53 or less, 1.52 or less, 1.51 or less, 1.50 or less, 1.495 or less, 1.490 or less, 1.488 or less, 1.487 or less, 1.486 or less, 1.485 or less, 1.484 or less, 1.483 or less, 1.482 or less, 1.481 or less, 1.480 or less, and particularly 1.479 or less. If the refractive index is too high, the reflectance at the air-glass interface increases, resulting in a low intensity of transmitted light to the back surface of the glass, which makes wiring defects more likely to occur when fabricating high-frequency devices. Here, "refractive index" is the value measured with a commercially available refractometer, for example, the KPR-2000 manufactured by Shimadzu Corporation.

[0087] The strain point is preferably 530°C or higher, 540°C or higher, 550°C or higher, 560°C or higher, 570°C or higher, 580°C or higher, and particularly 590°C or higher. If the strain point is too low, when the organic resin layer covering the wiring for protection needs to be heated and solidified during the fabrication of the high-frequency device, the glass is prone to thermal shrinkage, which makes wiring defects more likely to occur during the fabrication of the high-frequency device.

[0088] The liquid phase viscosity is preferably 10 3.4 dPa·s or higher, 10 3.6 dPa·s or higher, 10 3.8 dPa·s or higher, 10 4.0 dPa·s or higher, 10 4.2 dPa·s or higher, 10 4.6 dPa·s or higher, 10 4.8 dPa·s or higher, 10 5.0 dPa·s or higher, especially 10 5.2 The viscosity should be dPa·s or higher. If the liquid-phase viscosity is too low, the glass is more likely to devitrify during molding.

[0089] 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 The following, especially 0.1mm -1 The following applies: If the β-OH value is too large, it becomes difficult to ensure low dielectric properties. The "β-OH value" is calculated using a commercially available Fourier transform infrared spectrophotometer (FT-IR) with the following formula.

[0090] β-OH value = (1 / X)log(T1 / T2) X: Plate thickness (mm) T1: Reference wavelength 3846cm -1 Transmittance (%) T2: Hydroxyl group absorption wavelength 3600 cm -1 Minimum transmittance in the vicinity (%)

[0091] When the temperature is raised at a rate of 5°C / min, held at 500°C for 1 hour, and then cooled at a rate of 5°C / min, the thermal shrinkage rate is preferably 30 ppm or less, 25 ppm or less, 20 ppm or less, and particularly 18 ppm or less. If this thermal shrinkage rate is too high, when the organic resin layer covering the high-frequency device for wiring protection needs to be solidified by heating, the glass is more prone to thermal shrinkage, which can easily lead to wiring defects during the fabrication of the high-frequency device.

[0092] In the glass of the present invention, the thickness (plate thickness in the case of a plate) is preferably 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, and particularly 0.3 mm or less. If the thickness is too large, it becomes difficult to lighten and miniaturize high-frequency devices.

[0093] The arithmetic mean roughness Ra of the surface 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. The smoother the surface quality, the smaller the arithmetic mean roughness Ra of the metal wiring formed on the glass surface, which reduces the resistance loss that occurs when current is passed through the metal wiring of a high-frequency device. It also makes the glass less likely to break. On the other hand, the arithmetic mean roughness Ra of the surface is preferably 0.1 nm or more, 0.2 nm or more, and particularly 0.5 nm or more. The coarser the arithmetic mean roughness Ra of the surface, the less likely the metal wiring and functional film formed on the glass surface are to peel off. The "arithmetic mean roughness Ra" can be measured by a stylus-type surface roughness meter or an atomic force microscope (AFM).

[0094] The glass of the present invention is preferably formed by the overflow down-draw method. This method allows for the efficient production of glass plates with good surface quality without polishing. In addition to the overflow down-draw method, various other forming methods can be employed. For example, the slot-down method, float method, roll-out method, etc., can be used.

[0095] The present invention provides a method for measuring dielectric properties using a measurement standard material, characterized in that the measurement standard material is the glass described above. By using the glass of the present invention as the measurement standard material, dielectric properties can be measured stably over a long period of time.

[0096] In the dielectric properties measurement method of the present invention, the frequency of the dielectric properties to be measured is preferably 1 GHz or higher, 2 GHz or higher, 3 GHz or higher, 4 GHz or higher, 5 GHz or higher, 6 GHz or higher, 7 GHz or higher, 8 GHz or higher, 9 GHz or higher, and particularly 10 GHz or higher, and preferably 200 GHz or lower, 150 GHz or lower, 120 GHz or lower, and particularly 100 GHz or lower. If the measurement frequency falls outside the above range, it becomes difficult to evaluate the dielectric properties of the constituent materials of high-frequency devices used in 5G and the like.

[0097] In the dielectric properties measurement method of the present invention, the measurement temperature is preferably -40 to 150°C, -30 to 130°C, -20 to 120°C, -10 to 110°C, 0 to 100°C, 10 to 90°C, 20 to 80°C, and particularly 25 to 70°C. If the measurement temperature is outside the above range, it becomes difficult to evaluate the dielectric properties of the constituent materials of high-frequency devices used in 5G and the like.

[0098] In the dielectric properties measurement method of the present invention, it is preferable to heat-treat the glass used as the measurement standard material before measurement. The heating temperature is preferably above the annealing point of the glass, above 1°C above the annealing point, above 2°C above the annealing point, above 3°C above the annealing point, above 5°C above the annealing point, above 10°C above the annealing point, above 15°C above the annealing point, above 20°C above the annealing point, above 25°C above the annealing point, and particularly preferably above 29°C above the annealing point. The higher the heating temperature, the lower the moisture content in the glass, but if the heating temperature is too high, there is a risk that the glass will soften and deform. Therefore, the heating temperature is preferably below the softening point, below the softening point - 100°C, below the softening point - 200°C, below the softening point - 250°C, below the softening point - 280°C, below the softening point - 300°C, below the softening point - 320°C, below the softening point - 330°C, below the softening point - 340°C, and especially below the softening point - 350°C. The heating time is preferably 10 minutes or more, 20 minutes or more, 30 minutes or more, 40 minutes or more, 50 minutes or more, 60 minutes or more, 70 minutes or more, 80 minutes or more, 90 minutes or more, 100 minutes or more, 110 minutes or more, 120 minutes or more, 130 minutes or more, 140 minutes or more, 150 minutes or more, 160 minutes or more, 170 minutes or more, and especially 180 minutes or more. The longer the heating time, the lower the moisture content in the glass, but if the heating time is too long, the measurement efficiency will decrease. Therefore, the heating time is preferably 1000 minutes or less, 900 minutes or less, 800 minutes or less, 700 minutes or less, 600 minutes or less, 500 minutes or less, 400 minutes or less, and especially 300 minutes or less. [Examples]

[0099] The present invention will be described in detail below based on the following examples. Note that the following examples are merely illustrative. The present invention is not limited in any way to the following examples.

[0100] Tables 1-6 show examples of the present invention (samples No. 1-16, 21, 26, 27, 28) and comparative examples (samples No. 17-20, 22-25).

[0101] [Table 1]

[0102] [Table 2]

[0103] [Table 3]

[0104] [Table 4]

[0105] [Table 5]

[0106] [Table 6]

[0107] Samples No. 1 to 28 were prepared as follows. First, glass raw materials, prepared to match the compositions shown in the table, were placed in a platinum crucible and melted at 1650°C for 24 hours. After melting, the mixture was poured onto a carbon plate and formed into a flat plate. For the glass of sample No. 28, a crystal nucleation treatment was performed by heating at 770°C for 3 hours, followed by a crystal growth treatment by heating at 880°C for 1 hour to crystallize the glass. Next, each obtained sample was held at the annealing point +30°C for 30 minutes, cooled to room temperature at -3°C / min, and then measured for density, strain point Ps, annealing point Ta, softening point Ts, and 10°C. 4.0 Temperature in dPa·s, 10 3.0 Temperature in dPa·s, 10 2.5Temperature, liquidus temperature TL, liquidus viscosity logηTL, β-OH value, thermal expansion coefficient α, Young's modulus, shear modulus, Poisson's ratio, relative permittivity at 25°C and 2.45GHz, dielectric loss tangent at 25°C and 2.45GHz, and the relative permittivity and dielectric loss tangent at 25°C and 2.45GHz after steady-state temperature and humidity tests and high-temperature and high-humidity steady-state tests under various test conditions were evaluated.

[0108] The density was measured using the well-known Archimedes method.

[0109] The strain point Ps, slow cooling point Ta, and softening point Ts were measured according to the ASTM C336 and C338 methods.

[0110] 10 4.0 Temperature in dPa·s, 10 3.0 Temperature and 10 in dPa·s 2.5 The temperature in dPa·s was measured using the platinum ball pulling method.

[0111] The liquidus temperature TL is the value measured when glass powder that passed through a standard 30-mesh (500 μm) sieve and remained in a 50-mesh (300 μm) sieve was placed in a platinum boat and held in a temperature gradient furnace for 24 hours, and the temperature at which crystals precipitated was measured.

[0112] Liquid-phase viscosity logηTL is the viscosity of glass at liquid-phase temperature TL, measured using the platinum ball pulling method.

[0113] The β-OH value is the value measured by the method described above.

[0114] The thermal expansion coefficient α is a value measured with a dilatometer and is the average value within the stated temperature range.

[0115] Young's modulus and shear modulus were measured using the resonance method, and Poisson's ratio was calculated from these values.

[0116] The refractive index (nd, nC, nF, ne, ng, nh, ni, nF', LD785, LD1310, LD1550) is a value measured using the well-known V-block method, and can be measured using, for example, a commercially available refractometer KPR-2000 (manufactured by Shimadzu Corporation). The Abbe number νd is a value expressed by the formula (nd-1) / (nF-nC).

[0117] The relative permittivity and dielectric loss tangent at 25°C and a frequency of 2.45 GHz refer to values ​​measured using the well-known cavity resonator method. Note that 2.45 GHz is the resonant frequency of the air in the cavity resonator.

[0118] The temperature and humidity steady-state test was conducted using a commercially available high-temperature, high-humidity steady-state test machine under the conditions of a temperature of 85°C, a relative humidity of 85%, and a test duration of 1000 hours. The rate of change of the dielectric loss tangent (tanδ rate of change) was calculated as [(dielectric loss tangent after the test - dielectric loss tangent before the test) / (dielectric loss tangent after the test)] × 100.

[0119] The high-temperature, high-humidity steady-state test was conducted using a commercially available high-temperature, high-humidity steady-state test machine under conditions of 120°C, 85% relative humidity, and a test duration of 12 or 48 hours, referencing the conditions described in JIS-C0096-2001. The rate of change of dielectric loss tangent (tanδ rate of change) was calculated as [(dielectric loss tangent after test - dielectric loss tangent before test) / (dielectric loss tangent after test)] × 100.

[0120] For samples No. 1-16, 21, 26, 27, and 28, the dielectric loss tangent at a measurement frequency of 2.45 GHz and a measurement temperature of 25°C did not change significantly after steady-state temperature and humidity tests and high-temperature and high-humidity steady-state tests. However, for samples No. 17-20 and 22-25, the dielectric loss tangent at a measurement frequency of 2.45 GHz and a measurement temperature of 25°C changed significantly. [Examples]

[0121] Each sample after the temperature and humidity steady-state test and the high-temperature, high-humidity steady-state test was subjected to various heat treatments. The results are shown in Tables 7-9.

[0122] [Table 7]

[0123] [Table 8]

[0124] [Table 9]

[0125] First, the material was dried at 100°C for 24 hours, and then the dielectric loss tangent was measured at a measurement frequency of 2.45 GHz and a measurement temperature of 25°C. However, the dielectric loss tangent showed almost no change.

[0126] Next, for each sample after the temperature and humidity steady-state test and the high-temperature and high-humidity steady-state test, the sample was held at a temperature of +30°C, its slow-cooling point, for 30 minutes or 3 hours, then cooled to room temperature at -3°C / min, and the dielectric loss tangent was measured at a measurement frequency of 2.45 GHz and a measurement temperature of 25°C.

[0127] As can be seen from Tables 4-6, for samples No. 1-28, the longer the heating time, the closer the values ​​tended to be to those before the temperature and humidity steady-state test and the high-temperature and high-humidity steady-state test. From this, it can be seen that when the dielectric properties of a measurement standard material change due to dielectric property measurement, the predetermined heat treatment will return it to its initial dielectric properties. [Examples]

[0128] To investigate the mechanism by which the dielectric loss tangent changes, the following experiments were conducted on samples No. 7, 25, and 26.

[0129] First, for samples No. 7 and 25, the X-ray intensity of boron in the glass cross-section was analyzed before and after a high-temperature, high-humidity steady-state test under the conditions of 120°C, 85% relative humidity, and a test duration of 48 hours. Furthermore, for sample No. 25, the X-ray intensity of boron in the glass cross-section was analyzed after holding it at a temperature of +30°C (slow cooling point) for 3 hours and then cooling it to room temperature at -3°C / min.

[0130] Here, the X-ray intensity of boron distributed in the depth direction of the cross-section was analyzed using an EPMA (Electron Probe Microanalyzer, Shimadzu Corporation EPMA-1720). Glass fracture surfaces before and after heat treatment were used as analytical samples, and the characteristic X-ray intensity values ​​(unit: Count) of the boron element's Kα rays at positions (depths) of 0 μm, 1.5 μm, 2.5 μm, 5 μm, 10 μm, and 15 μm from the outermost surface of the glass were calculated by point analysis to confirm the distribution of boron X-ray intensity in the depth direction of the glass. Here, for a depth of 0 μm, if the fracture surface is measured, the beam diameter of the irradiated X-rays does not irradiate the fracture surface, so the measurement value at the outermost surface of the side of the glass was used as the boron X-ray intensity at a depth of 0 μm. The measurement conditions were as follows: acceleration voltage: 15kV, beam current: 20nA, beam diameter: minimum, measurement time: 10 sec. / point, and element measured: B (BKα: Wavelength (Å): 68.486). The results are shown in Figure 1.

[0131] Compositional analysis revealed that in sample No. 25, after high-temperature, high-humidity steady-state testing, the X-ray intensity of boron decreased from the outermost surface to a depth of 1.5 μm compared to before testing. Furthermore, after heat treatment, the X-ray intensity of boron decreased to a depth of 2.5 μm compared to before testing. On the other hand, in sample No. 7, after high-temperature, high-humidity steady-state testing, the X-ray intensity of boron did not change in the depth direction compared to before testing. Although sample No. 26 has not been measured, it is presumed that a similar phenomenon occurred to that in sample No. 25 based on the behavior of the change in dielectric properties and its similar glass composition.

[0132] Next, to investigate the effect of changes in the composition of the glass surface on the dielectric loss tangent of samples No. 7, 25, and 26, a high-temperature, high-humidity steady-state test was conducted under the conditions of 120°C, 85% relative humidity, and 48 hours of testing. After that, the glass surface was polished with sandpaper without applying moisture. Based on the compositional analysis results, the amount of boron in the samples after the high-temperature, high-humidity steady-state test had decreased to a depth of approximately 1 μm from the glass surface, so a thickness of 3 μm was polished from the glass surface. After polishing, the relative permittivity and dielectric loss tangent were measured using the cavity resonator method at 25°C and a frequency of 2.45 GHz. The results are shown in Figure 2.

[0133] As can be seen in Figure 2, the dielectric loss tangent of samples No. 25 and 26 after polishing was the same as before the high-temperature, high-humidity steady-state test. On the other hand, the dielectric loss tangent of sample No. 7 was the same before and after the high-temperature, high-humidity steady-state test, and remained the same after polishing. The relative permittivity of samples No. 7, 25, and 26 did not change significantly before and after polishing.

[0134] Finally, for samples No. 7, 25, and 26, the reflectance and transmittance spectra in the infrared wavelength range were measured using the aforementioned Fourier transform infrared spectrophotometer (FT-IR) under the conditions of a temperature of 120°C, a relative humidity of 85%, and a test duration of 48 hours. This measurement was performed before and after the high-temperature, high-humidity steady-state test, and after holding the samples at a temperature of +30°C (slow cooling point) for 3 hours, followed by cooling to room temperature at -3°C / min. In addition, the β-OH values ​​for each sample were calculated from the transmittance spectra. The reflectance spectra of sample No. 7, sample No. 25, and sample No. 26 are shown in Figure 3(a), Figure 3(b), and Figure 3(c), respectively. The transmittance spectra of sample No. 7, sample No. 25, and sample No. 26 are shown in Figure 4(a), Figure 4(b), and Figure 4(c), respectively. The changes in the β-OH values ​​for samples No. 7, No. 25, and No. 26 are shown in Figure 5.

[0135] As can be seen from Figures 3 and 4, changes were observed in the reflectance and transmittance spectra of samples No. 25 and 26 before and after the high-temperature, high-humidity steady-state test and after heat treatment. This indicates that the bonding state and amount of silicon atoms (Si) and oxygen atoms (O) and boron atoms (B) and O in the glass, as well as the amount of water, have changed, suggesting that the structure of the glass has changed. Note that in the reflectance spectrum of Figure 3, at 900 cm⁻¹ -1 , 1300~1500cm -1 The peaks in the vicinity represent the stretching vibrations of BO3 and BO4, at 1100cm. -1 The peaks in the vicinity represent the stretching vibrations of the Si-O bond. In the transmittance spectrum of Figure 4, at 3600 cm⁻¹ -1 The peaks in the vicinity represent hydroxyl groups that form hydrogen bonds with non-crosslinked oxygen in the glass.

[0136] For samples No. 7, 25, and 26, the β-OH values ​​were calculated from the transmittance spectra. For samples No. 25 and 26, the β-OH values ​​increased after the high-temperature, high-humidity steady-state test compared to before the test. Furthermore, after heat treatment following the high-temperature, high-humidity steady-state test, the β-OH values ​​decreased to those below the level before the test. On the other hand, for sample No. 7, the β-OH value did not change in any of the measurements.

[0137] Figure 6(a) shows the relationship between the dielectric loss tangent and the β-OH value for sample No. 7 at 25°C and a frequency of 2.45 GHz. Figure 6(b) shows the relationship between the dielectric loss tangent and the β-OH value for sample No. 25 at 25°C and a frequency of 2.45 GHz. Figure 6(c) shows the relationship between the dielectric loss tangent and the β-OH value for sample No. 26 at 25°C and a frequency of 2.45 GHz.

[0138] The following is an estimate of the mechanism by which the dielectric loss tangent changed.

[0139] Based on the measurement results of the relative permittivity and dielectric loss tangent after polishing the surface by 3 μm as shown in Figure 2, it is presumed that the change in dielectric loss tangent in this case was caused by a change in the glass surface.

[0140] No foreign matter precipitation was observed in samples No. 25 and 26 after the high-temperature, high-humidity steady-state test. Based on the compositional analysis results in Figure 1, it is presumed that boron on the glass surface sublimated as H3BO3 during the high-temperature, high-humidity steady-state test. Furthermore, it is presumed that H2O entered the spaces where H3BO3 had detached from the glass surface during the high-temperature, high-humidity steady-state test, and some of it bonded as hydroxyl groups (-OH), thus increasing the β-OH value, which is an indicator of the moisture content in the glass after the high-temperature, high-humidity steady-state test. Additionally, it is inferred that when heat treatment was performed after the high-temperature, high-humidity steady-state test, hydroxyl groups on the glass surface were removed as H2O, reducing the number of hydroxyl groups, which led to a decrease in the β-OH value after heat treatment and brought the dielectric loss tangent closer to the value before the test (see Figure 6).

[0141] The reason why the dielectric loss tangent changes with changes in the β-OH value, i.e., changes in the amount of water, is thought to be partly due to the influence of polarization of hydroxyl groups (-OH) and water molecules, which are presumed to be present in the voids of the glass network. Generally, hydroxyl groups tend to polarize due to the difference in electronegativity of their constituent elements (O and H), and when an electromagnetic field is applied from the outside, the polarized hydroxyl groups attempt to orient themselves in accordance with the electromagnetic field. The dielectric loss tangent indicates the delay in the orientation of polarized molecules when an electromagnetic field is applied, and the dielectric loss tangent also changes depending on the amount of hydroxyl groups. For the same glass composition, it is thought that the more hydroxyl groups there are, the higher the dielectric loss tangent (see Figure 6).

[0142] Based on the results of this investigation, it is presumed that sample No. 7 did not experience a change in dielectric loss tangent compared to samples No. 25 and 26, for example, because it had less boron in its composition and lower reactivity with water (see Figure 6). Therefore, this phenomenon indicates that the change in dielectric loss tangent can be effectively suppressed by setting the glass composition within a suitable range, particularly by setting the product of the content of B2O3-Al2O3 (mol%) and the content of B2O3-(MgO+CaO+SrO+BaO) (mol%) to 600 or less, and especially to 260 or less. [Industrial applicability]

[0143] The glass of the present invention is suitable as a standard sample for measuring dielectric properties in the high-frequency range, but it is also suitable as a substrate for printed circuit boards, glass antennas, micro-LEDs, glass interposers, and as a backgrind substrate for dissimilar materials such as metals and ceramics, where low dielectric properties are required.

Claims

1. As components, in mol%, SiO ２ 81.67 to 85%, Al ２ O ３ 0 to 5%, B ２ O ３ 12.55 to 20%, Li ２ O 0 to 5%, Na ２ O 1 to 10%, K ２ O 0 to 5%, Li ２ O + Na ２ O + K ２ O 3 to 10%, and the change rate of the dielectric tangent at a measurement frequency of 2.45 GHz and a measurement temperature of 25°C after performing a temperature and humidity steady state test at a temperature of 85°C, a relative humidity of 85%, and for 1000 hours is 30% or less. A glass characterized by this.

2. It is a crystallized glass, and its composition is SiO₂ in mol%. ２ 55-75%, Al ２ O ３ 10-20%, Li ２ O 2% or more, TiO ２ 0.5-3%, TiO ２ +ZrO ２ 2-5%, SnO ２ A glass characterized by containing 0.1 to 0.5% of a certain substance, and having a rate of change in the dielectric loss tangent of 30% or less at a measurement frequency of 2.45 GHz and a measurement temperature of 25°C after a steady-state temperature and humidity test at a temperature of 85°C, relative humidity of 85%, and for 1000 hours.

3. The glass according to claim 1 or 2, characterized in that the rate of change in dielectric loss tangent at a measurement frequency of 2.45 GHz and a measurement temperature of 25°C after performing a high-temperature, high-humidity steady-state test (JIS-C0096-2001) at a temperature of 120°C, relative humidity of 85%, for 12 hours is 30% or less.

4. The glass according to any one of claims 1 to 3, characterized in that, after performing a high-temperature, high-humidity steady-state test (JIS-C0096-2001) at a temperature of 120°C, relative humidity of 85%, for 48 hours, the depth at which the X-ray intensity of boron analyzed from the outermost surface in the depth direction decreases by 50% relative to a depth of 15 μm is 5 μm or less.

5. B in composition ２ O ３ - Al ２ O ３ The content (mol%) and B ２ O ３ The glass according to any one of claims 1 to 4, characterized in that the product of the content (mol%) of -(MgO + CaO + SrO + BaO) is 260 or less.

6. The glass according to any one of claims 1 to 5, characterized in that it is used as a measurement standard material when measuring dielectric properties.

7. A method for measuring dielectric properties using a measurement standard material, A method for measuring dielectric properties, characterized in that the glass described in any one of claims 1 to 6 is used as the measurement standard material.

8. The method for measuring dielectric properties according to claim 7, characterized in that, before measuring the dielectric properties, the measurement standard material is heat-treated at a temperature above the annealing point of glass.

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