Abstract: In an alumina-based sintered body containing alumina (Al2O3) as a main component and containing magnesia (MgO) whose content with respect to a content of the alumina is 0.00 mol %<MgO?0.20 mol %, a density is 3.96 g/cm3 or greater, and a standard deviation of grain sizes of alumina crystal grains is smaller than 4.0 ?m.

Abstract: A first ceramic member and a second ceramic member are joined together at a lower joining temperature while reducing the loss of bond strength. A method for producing a semiconductor production device component includes a step of providing a first ceramic member including an AlN-based material, a step of providing a second ceramic member including an AlN-based material, and a step of joining the first ceramic member and the second ceramic member to each other by thermally pressing the first ceramic member and the second ceramic member to each other via a joint agent including Eu2O3, Gd2O3 and Al2O3 disposed between the first ceramic member and the second ceramic member.

Abstract: A semiconductor production device component includes a first ceramic member including an AlN-based material, a second ceramic member including an AlN-based material, and a joint layer disposed between the first ceramic member and the second ceramic member so as to join the first ceramic member and the second ceramic member to each other. The joint layer includes a composite oxide containing Gd and Al, and Al2O3, and is free from AlN.

Abstract: The scattering of a rare earth hydroxide is suppressed, and the loss of bond strength between a first ceramic member and a second ceramic member is reduced. A semiconductor production device component includes a first ceramic member including an AlN-based material, a second ceramic member including an AlN-based material, and a joint layer disposed between the first ceramic member and the second ceramic member so as to join the first ceramic member and the second ceramic member to each other, wherein the joint layer includes a perovskite oxide represented by ABO3 (wherein A is a rare earth element, and B is Al) and includes no rare earth single oxide containing exclusively a rare earth element and oxygen.

Abstract: A first ceramic member and a second ceramic member are joined together at a lower joining temperature while reducing the loss of bond strength. A method for producing a semiconductor production device component includes a step of providing a first ceramic member including an AlN-based material, a step of providing a second ceramic member including an AlN-based material, and a step of joining the first ceramic member and the second ceramic member to each other by thermally pressing the first ceramic member and the second ceramic member to each other via a joint agent including Eu2O3, Gd2O3 and Al2O3 disposed between the first ceramic member and the second ceramic member.

Abstract: A semiconductor production device component includes a first ceramic member including an AlN-based material, a second ceramic member including an AlN-based material, and a joint layer disposed between the first ceramic member and the second ceramic member so as to join the first ceramic member and the second ceramic member to each other. The joint layer includes a composite oxide containing Gd and Al, and Al2O3, and is free from AlN.

Abstract: A dielectric structure including a metal foil, a dielectric layer and a conductor layer provided in this order, wherein the metal foil has a thickness of from 10 to 40 ?m, the dielectric layer has a thickness of from 0.3 to 5 ?m, and the conductor layer has a thickness of from 0.3 to 10 ?m. The dielectric structure has plural vias which are separated from each other, and which penetrate through both of the dielectric layer and the conductor layer. The vias of the dielectric layer have different diameters which are in a range of from 100 to 300 ?m, a diameter of each of the vias of the conductor layer is larger than a diameter of a corresponding via of the dielectric layer by 5 to 50 ?m, and a minimum via pitch is from 100 to 350 ?m.

Abstract: A dielectric structure including a metal foil, a dielectric layer and a conductor layer provided in this order, wherein the metal foil has a thickness of from 10 to 40 ?m, the dielectric layer has a thickness of from 0.3 to 5 ?m, and the conductor layer has a thickness of from 0.3 to 10 ?m. The dielectric structure has plural vias which are separated from each other, and which penetrate through both of the dielectric layer and the conductor layer. The vias of the dielectric layer have different diameters which are in a range of from 100 to 300 ?m, a diameter of each of the vias of the conductor layer is larger than a diameter of a corresponding via of the dielectric layer by 5 to 50 ?m, and a minimum via pitch is from 100 to 350 ?m.

Abstract: A dielectric structure including a metal foil, a dielectric layer and a conductor layer provided in this order, wherein the metal foil has a thickness of from 10 to 40 ?m, the dielectric layer has a thickness of from 0.3 to 5 ?m, and the conductor layer has a thickness of from 0.3 to 10 ?m. The dielectric structure has plural vias which are separated from each other, and which penetrate through both of the dielectric layer and the conductor layer. The vias of the dielectric layer have different diameters which are in a range of from 100 to 300 ?m, a diameter of each of the vias of the conductor layer is larger than a diameter of a corresponding via of the dielectric layer by 5 to 50 ?m, and a minimum via pitch is from 100 to 350 ?m.

Abstract: A dielectric structure comprising: a metal foil; a dielectric layer; and a conductor layer provided in this order, wherein the metal foil has a thickness of from 10 to 40 ?m, the dielectric layer has a thickness of from 0.3 to 5 ?m, and the conductor layer has a thickness of from 0.3 to 10 ?m, the dielectric structure has plural vias which are separated from each other, and which penetrate through both of the dielectric layer and the conductor layer, and the vias of the dielectric layer have different diameters which are in a range of from 100 to 300 ?m, a diameter of each of the vias of the conductor layer is larger than a diameter of a corresponding via of the dielectric layer by 5 to 50 ?m, and a minimum via pitch is from 100 to 350 ?m.