A glass substrate for high-frequency devices includes, in terms of molar percentage based on oxides: one or more alkaline-earth metal oxides in a total amount of 0.1 to 13%; Al.sub.2O.sub.3 and B.sub.2O.sub.3 in a total amount of 1 to 40%, in which a molar ratio of the contents represented by Al.sub.2O.sub.3/(Al.sub.2,O.sub.3+B.sub.2O.sub.3) is 0 to 0.45; at least one oxide selected from the group consisting of Sc.sub.2O.sub.3, TiO.sub.2, ZnO, Ga.sub.2O.sub.3, GeO.sub.2, Y.sub.2O.sub.3, ZrO.sub.2, Nb.sub.2O.sub.5, In.sub.2O.sub.3, TeO.sub.2, HfO.sub.2, Ta.sub.2O.sub.5, WO.sub.3, Bi.sub.2O.sub.3, La.sub.2O.sub.3, Gd.sub.2O.sub.3, Yb.sub.2O.sub.3, and Lu.sub.2O.sub.3, in a total amount of 0.1 to 1.0%; and SiO.sub.2 as a main component. The glass substrate has a dielectric dissipation factor at 35 GHz of 0.007 or less.

A glass substrate for a high-frequency device, which contains, in terms of mole percent on the basis of oxides: 40 to 75% of SiO.sub.2; 0 to 15% of Al.sub.2O.sub.3; 13 to 23% of B.sub.2O.sub.3; 2.5 to 11% of MgO; and 0 to 13% of CaO, and having a total content of alkali metal oxides in the range of 0.001-5%, where at least one main surface of the glass substrate has a surface roughness of 1.5 um or less in terms of arithmetic average roughness Ra. and the glass substrate has a dielectric dissipation factor at 35 GHz of 0.007 or less.

A glass substrate for a high-frequency device, which contains, in terms of mole percent on the basis of oxides: 40 to 75% of SiO.sub.2; 0 to 15% of Al.sub.2O.sub.3; 13 to 23% of B.sub.2O.sub.3; 2.5 to 11% of MgO; and 0 to 13% of CaO, and having a total content of alkali metal oxides in the range of 0.001-5%, where at least one main surface of the glass substrate has a surface roughness of 1.5 um or less in terms of arithmetic average roughness Ra. and the glass substrate has a dielectric dissipation factor at 35 GHz of 0.007 or less.

The present invention relates to a glass substrate for a high-frequency device, which includes SiO.sub.2 as a main component, the glass substrate having a total content of alkali metal oxides in the range of 0.001-5% in terms of mole percent on the basis of oxides, the alkali metal oxides having a molar ratio represented by Na.sub.2O/(Na.sub.2O+K.sub.2O) in the range of 0.01-0.99, and the glass substrate having a total content of Al.sub.2O.sub.3 and B.sub.2O.sub.3 in the range of 1-40% in terms of mole percent on the basis of oxides and having a molar ratio represented by Al.sub.2O.sub.3/(Al.sub.2O.sub.3+B.sub.2O.sub.3) in the range of 0-0.45, in which at least one main surface of the glass substrate has a surface roughness of 1.5 nm or less in terms of arithmetic average roughness Ra, and the glass substrate has a dielectric dissipation factor at 35 GHz of 0.007 or less.

The present invention relates to a glass substrate for a high-frequency device, which includes SiO.sub.2 as a main component, the glass substrate having a total content of alkali metal oxides in the range of 0.001-5% in terms of mole percent on the basis of oxides, the alkali metal oxides having a molar ratio represented by Na.sub.2O/(Na.sub.2O+K.sub.2O) in the range of 0.01-0.99, and the glass substrate having a total content of Al.sub.2O.sub.3 and B.sub.2O.sub.3 in the range of 1-40% in terms of mole percent on the basis of oxides and having a molar ratio represented by Al.sub.2O.sub.3/(Al.sub.2O.sub.3+B.sub.2O.sub.3) in the range of 0-0.45, in which at least one main surface of the glass substrate has a surface roughness of 1.5 nm or less in terms of arithmetic average roughness Ra, and the glass substrate has a dielectric dissipation factor at 35 GHz of 0.007 or less.

A glass-ceramic includes SiO.sub.2 in a range of 40 mol. % to 80 mol. %; Al.sub.2O.sub.3 in a range of 5 mol. % to 20 mol. %; MgO in a range of 5 mol. % to 20 mol. %; and at least one of B.sub.2O.sub.3, ZnO, and TiO.sub.2, each in a range of 0 mol. % to 10 mol. %, such that the glass-ceramic further comprises a magnesium aluminosilicate crystalline phase at a concentration in a range of 5 wt. % to 80 wt. % of the glass-ceramic.

A glass-ceramic includes SiO.sub.2 in a range of 40 mol. % to 80 mol. %; Al.sub.2O.sub.3 in a range of 5 mol. % to 20 mol. %; MgO in a range of 5 mol. % to 20 mol. %; and at least one of B.sub.2O.sub.3, ZnO, and TiO.sub.2, each in a range of 0 mol. % to 10 mol. %, such that the glass-ceramic further comprises a magnesium aluminosilicate crystalline phase at a concentration in a range of 5 wt. % to 80 wt. % of the glass-ceramic.

A glass material with low viscosity and a low bubble content attributable to a low weight percentage of silicon dioxide includes boron trioxide (B.sub.2O.sub.3), magnesium oxide (MgO). aluminum oxide (Al.sub.2O.sub.3), and calcium oxide (CaO) in addition to silicon dioxide (SiO.sub.2); wherein Silicon dioxide (SiO.sub.2) constitutes 45%51% by weight of the glass material, boron trioxide (B.sub.2O.sub.3) 25%35%, magnesium oxide (MgO) 0.01%2%, aluminum oxide (Al.sub.2O.sub.3) 10%14.5%, and calcium oxide (CaO) 4%10%. As the silicon dioxide (SiO.sub.2) content is lower than in the prior art, the glass material has lower viscosity, and hence a lower bubble content, than in the prior art, and this allows products made of the glass material to have a higher yield than products made of the conventional glass.

Provided is a glass substrate with which it is possible to reduce dielectric loss in high-frequency signals, and which also has excellent thermal shock resistance. This invention satisfies the relation {Young's modulus (GPa)average thermal expansion coefficient (ppm/ C.) at 50-350 C}300 (GPa.Math.ppm/ C.), wherein the relative dielectric constant at 20 C. and 35 GHz does not exceed 10, and the dielectric dissipation factor at 20 C. and 35 GHz does not exceed 0.006.

A glass ceramic sintered body having a small dielectric loss in a high frequency band of 10 GHz or higher and stable characteristics against temperature variation and a wiring substrate using the same are provided. The glass ceramic sintered body contains crystallized glass, an alumina filler, silica, and strontium titanate. The content of the crystallized glass is 50 mass % to 80 mass %, the content of the alumina filler is 15.6 mass % to 31.2 mass % in terms of Al.sub.2O.sub.3, the content of silica is 0.4 mass % to 4.8 mass % in terms of SiO.sub.2, and the content of the strontium titanate is 4 mass % to 14 mass % in terms of SrTiO.sub.3.