Abstract: A cordierite sintered body and a member for semiconductor manufacturing apparatus are disclosed. The cordierite sintered body includes a crystal phase and an amorphous phase. The crystal phase includes a main crystal phase that essentially consists of cordierite crystal grains; and a sub crystal phase that includes sub crystal grains containing alumina, mullite or sapphirine. The amorphous phase contains calcium and is located at grain boundaries of the cordierite crystal grains and the sub crystal grains. A crystal phase proportion of the main crystal phase to the crystal phase (or total of the main crystal phase and the sub crystal phase) is 95% to 97.5% by mass or less. A crystal phase proportion of the sub crystal phase to the crystal phase is 2.5% to 5% by mass or less. The sintered body contains calcium by 0.4% to 0.6% by mass or less in terms of CaO.

Abstract: An alumina sintered article comprising 99.3 mass % or more Al in terms of Al2O3, strontium and silicon is disclosed. The alumina sintered article also comprises alumina crystal grains and an oxide crystal comprising aluminum, silicon, strontium located at a triple pocket surrounded by three or more alumina crystal grains. The alumina sintered article improves dielectric loss in the megahertz to gigahertz bands while maintaining corrosion resistance, mechanical properties of alumina.

Abstract: An alumina sintered article comprising 99.3 mass % or more Al in terms of Al2O3, strontium and silicon is disclosed. The alumina sintered article also comprises alumina crystal grains and an oxide crystal comprising aluminum, silicon, strontium located at a triple pocket surrounded by three or more alumina crystal grains. The alumina sintered article improves dielectric loss in the megahertz to gigahertz bands while maintaining corrosion resistance, mechanical properties of alumina.

Abstract: There is provided a dimensionally accurate insulating substrate in which plane direction-wise shrinkage is practically zero and shrinkage variations are small. The insulating substrate includes a laminated body composed of at least two kinds of insulating layers made of crystallizable glass ceramics. The crystallization temperature of crystallizable glass contained in the first insulating layer is lower than the softening point of crystallizable glass contained in the second insulating layer. The difference in thermal expansion coefficient between the first and second insulating layers is preferably 2×10?6/° C. or below.

Abstract: A laminate includes a first green sheet and a second green sheet. The first green sheet includes a first glass including Al and M which is at least one of Sr and Ba. A relationship between Al content and M content is so defined that a position represented by percent by mass of Al in terms of Al2O3 and percent by mass of M in terms of MO on a coordinate system are on or in a range defined by straight lines connecting point A (1, 21), point B (1, 35), point C (9, 45), point D (20, 45), point E (20, 35), and point F (9, 21) on the coordinate system. The second green sheet includes a second glass including Si and B. The first green sheet is integrally laminated with the second green sheet.

Abstract: An optical glass consisting essentially of B2O3 in an amount of 10-40 wt %, SiO2 in an amount less than or equal to 5 wt %, ZnO in an amount less than or equal to 15 wt %, SrO in an amount less than or equal to 9 wt %, ZrO2 in an amount less than or equal to 9 wt %, La2O3 in an amount of 15 to 45 wt %, BaF2 in an amount of 1 to 10 wt %, BaO in an amount less than or equal to 5 wt %, HfO2 in an amount of 0.1 to 7.5 wt %, Gd2O3 in an amount less than or equal to 16 wt %, CaO in an amount less than or equal to 7 wt %, ZrF4 in an amount less than or equal to 5 wt %, Na2O in an amount less than or equal to 2 wt % and Y2O3 in an amount less than or equal to 16 wt %. The optical glass has a glass transition temperature in a range of 500-670° C. and a refractive index (nd) in a range of 1.60 to 2.00.

Abstract: An optical glass consisting essentially of B2O3 in an amount of 10-40 wt %, SiO2 in an amount less than or equal to 5 wt %, ZnO in an amount less than or equal to 15 wt %, SrO in an amount less than or equal to 9 wt %, ZrO2 in an amount less than or equal to 9 wt %, La2O3 in an amount of 15 to 45 wt %, BaF2 in an amount of 1 to 10 wt %, BaO in an amount less than or equal to 5 wt %, HfO2 in an amount of 0.1 to 7.5 wt %, Gd2O3 in an amount less than or equal to 16 wt %, CaO in an amount less than or equal to 7 wt %, ZrF4 in an amount less than or equal to 5 wt %, Na2O in an amount less than or equal to 2 wt % and Y2O3 in an amount less than or equal to 16 wt %. The optical glass has a glass transition temperature in a range of 500-670° C. and a refractive index (nd) in a range of 1.60 to 2.00.

Abstract: There is provided a dimensionally accurate insulating substrate in which plane direction-wise shrinkage is practically zero and shrinkage variations are small. The insulating substrate includes a laminated body composed of at least two kinds of insulating layers made of crystallizable glass ceramics. The crystallization temperature of crystallizable glass contained in the first insulating layer is lower than the softening point of crystallizable glass contained in the second insulating layer. The difference in thermal expansion coefficient between the first and second insulating layers is preferably 2×10?6/° C. or below.

Abstract: A laminate includes a first green sheet and a second green sheet. The first green sheet includes a first glass including Al and M which is at least one of Sr and Ba. A relationship between Al content and M content is so defined that a position represented by percent by mass of Al in terms of Al2O3 and percent by mass of M in terms of MO on a coordinate system are on or in a range defined by straight lines connecting point A (1, 21), point B (1, 35), point C (9, 45), point D (20, 45), point E (20, 35), and point F (9, 21) on the coordinate system. The second green sheet includes a second glass including Si and B. The first green sheet is integrally laminated with the second green sheet.

Abstract: There is provided a dimensionally accurate insulating substrate in which plane direction-wise shrinkage is practically zero and shrinkage variations are small. The insulating substrate includes a laminated body composed of at least two kinds of insulating layers made of crystallizable glass ceramics. The crystallization temperature of crystallizable glass contained in the first insulating layer is lower than the softening point of crystallizable glass contained in the second insulating layer. The difference in thermal expansion coefficient between the first and second insulating layers is preferably 2×10?6/° C. or below.

Abstract: The present invention provides a dielectric ceramic composition comprising: 30 to 90% by weight of a crystallized glass powder capable of depositing a diopside crystal, 1 to 40% by weight of a calcium titanate powder, a strontium titanate powder or a mixed powder thereof, and 0 to 60% by weight of at least one kind of a powder selected from the group consisting of Al2O3, TiO2, ZrO2, MgTiO3, BaTi4O9, La2Ti2O7, Nd2Ti2O7, Ca2Nb2O7, SrZrO3 and CaZrO3, and a dielectric ceramics obtained by firing the same.

Abstract: The present invention provides a dielectric ceramic composition comprising: 30 to 90% by weight of a crystallized glass powder capable of depositing a diopside crystal, 1 to 40% by weight of a calcium titanate powder, a strontium titanate powder or a mixed powder thereof, and 0 to 60% by weight of at least one kind of a powder selected from the group consisting of Al2O3, TiO2, ZrO2, MgTiO3, BaTi4O9, La2Ti2O7, Nd2Ti2O7, Ca2Nb2O7, SrZrO3 and CaZrO3, and a dielectric ceramics obtained by firing the same.

Abstract: A circuit substrate in which the conductor portions constituting the functional devices formed in the insulating board have interfacial electric conductivities &sgr; of not larger than 2.90×107 &OHgr;−1·m−1 to greatly lower the insertion losses.

Abstract: A dielectric ceramic composition being characterized in that the composition contains at least Ba and Ti as metal elements, and when the formula of the composition in accordance with the mole ratios of these elements is represented by BaO.xTiO.sub.2, the composition contains the main ingredient determined by x satisfying the relationship of 3.9.ltoreq.x.ltoreq.4.1, and 0.01 to 7 weight parts of Cu in terms of CuO, and, if necessary, 20 or less weight parts of Zn in terms of ZnO with respect to 100 weight parts of the main ingredient, whereby the dielectric coefficient can have a value in the range of 30 to 42, and Qf can have a value of 40000 GHz or more, the temperature coefficient .pi..sub.f of the resonance frequency can have a value in the range of -15 to +15 ppm/.degree.C., and the temperature drift .DELTA..pi..sub.f of the temperature coefficient .pi..sub.f of the resonance frequency can have a value in the range of -2 to +2 ppm/.degree.C.