Abstract: Crystal grains mainly composed of barium titanate have a mean grain size of not more than 0.2 ?m. The volume per unit cell V that is represented by a product of lattice constant (a, b, c) figured out from the X-ray diffraction pattern of the crystal grains is not more than 0.0643 nm3. Thereby, a dielectric ceramics having high relative dielectric constant can be obtained. A multilayer ceramic capacitor comprises a capacitor body and an external electrode that is formed at both ends of the capacitor body. The capacitor body comprises dielectric layers composed of the dielectric ceramics, and internal electrode layers. The dielectric layers and the internal electrode layers are alternately laminated.

Abstract: A multilayer electronic component is composed of a ceramic body obtained by laminating a plurality of ceramic layers via a conductor layer. The conductor layer is a plated film and extracted to one end face of the ceramic body, thereby contributing to the formation of capacity. A peripheral edge portion of the conductor layer composed of the plated film is thicker than its inner region. This avoids stripping on the peripheral edge portion of the conductor layer and avoids internal defects such as delamination. A dummy conductor layer may be formed at a distance on the end opposite the end face for extraction.

Abstract: Crystal grains mainly composed of barium titanate have a mean grain size of not more than 0.2 ?m. The volume per unit cell V that is represented by a product of lattice constant (a, b, c) figured out from the X-ray diffraction pattern of the crystal grains is not more than 0.0643 nm3. Thereby, a dielectric ceramics having high relative dielectric constant can be obtained. A multilayer ceramic capacitor comprises a capacitor body and an external electrode that is formed at both ends of the capacitor body. The capacitor body comprises dielectric layers composed of the dielectric ceramics, and internal electrode layers. The dielectric layers and the internal electrode layers are alternately laminated.

Abstract: A multilayer electronic component is composed of a ceramic body obtained by laminating a plurality of ceramic layers via a conductor layer. The conductor layer is a plated film and extracted to one end face of the ceramic body, thereby contributing to the formation of capacity. A peripheral edge portion of the conductor layer composed of the plated film is thicker than its inner region. This avoids stripping on the peripheral edge portion of the conductor layer and avoids internal defects such as delamination. A dummy conductor layer may be formed at a distance on the end opposite the end face for extraction.

Abstract: A member used within a plasma processing apparatus and exposed to a plasma of a halogen gas such as BCl3 or Cl2 is formed from a sintered body of metals of Group IIIa of Periodic Table such as Y, La, Ce, Nd and Dy, and Al and/or Si, for example, 3Y2O3.5Al2O3, 2Y2O3.Al2O3, Y2O3.Al2O3 or disilicate or monosilicate, and in particular, in this sintered body, the content of impurity metals of Group IIa of Periodic Table contained in the sintered body is controlled to be 0.15 wt % or more in total. Specifically, for this member, an yttrium-aluminum-garnet sintered body having a porosity of 3% or less and also having a surface roughness of 1 ?m or less in center line average roughness Ra is utilized.

Abstract: A member used within a plasma processing apparatus and exposed to a plasma of a halogen gas such as BCl3 or Cl2 is formed from a sintered body of metals of Group IIIa of Periodic Table such as Y, La, Ce, Nd and Dy, and Al and/or Si, for example, 3Y2O3.5Al2O3, 2Y2O3.Al2O3, Y2O3.Al2O3 or disilicate or monosilicate, and in particular, in this sintered body, the content of impurity metals of Group IIa of Periodic Table contained in the sintered body is controlled to be 0.15 wt % or more in total. Specifically, for this member, an yttrium-aluminum-garnet sintered body having a porosity of 3% or less and also having a surface roughness of 1 &mgr;m or less in center line average roughness Ra is utilized.

Abstract: A member used within a plasma processing apparatus and exposed to a plasma of a halogen gas such as BCl3 or Cl2 is formed from a sintered body of metals of Group IIIa of Periodic Table such as Y, La, Ce, Nd and Dy, and Al and/or Si, for example, 3Y2O3·5Al2O3, 2Y2O3·Al2O3, Y2O3·Al2O3 or disilicate or monosilicate, and in particular, in this sintered body, the content of impurity metals of Group IIa of Periodic Table contained in the sintered body is controlled to be 0.15 wt % or more in total. Specifically, for this member, an yttrium-aluminum-garnet sintered body having a porosity of 3% or less and also having a surface roughness of 1 &mgr;m or less in center line average roughness Ra is utilized.

Abstract: The present invention is to provide ceramic members for being used as members constituting a processing chamber for etching or cleaning semiconductor substrates or wafers by halogen plasma. A ceramic member includes at least 10% by volume of a compound of yttrium-aluminum-garnet (YAG) phase and not more than 90% by volume of at least an oxide phase selected from aluminum oxide, yttrium oxide and aluminum nitride. Particularly, the ceramic member contains yttrium within a range of 35 to 80 mole % in terms of yttrium oxide Y2O3 and aluminum within a range of 20 to 65 mole % in terms of aluminum oxide Al2O3 to form a mixture of YAG phase with yttria phase, producing ceramic material having high corrosion resistance to halogenous gas and its plasma. Such ceramic material may be well applicable to members to be exposed by the halogen plasma, for example, a chamber wall, a wafer stage, a clamp ring, a shower head, which are used in systems for etching and cleaning semiconductor wafers.

Abstract: This invention relates to a corrosion-resistant member used in a region in which a gas or a plasma of a halogen-containing compound is used, in a process for producing semiconductors, especially a member used as jigs such as a supporter for supporting a material to be treated, or as an inner wall member in an apparatus for producing semiconductors, which has a high corrosion resistance to a fluorine type or a chlorine type corrosive gas, or a fluorine type or a chlorine type plasma. According to this invention, there are provided a corrosion-resistant member to be used ina region in which a gas or plasma of a halogen compound is used in a process of producing a semiconductor, wherein at least surface exposed to the gas or plasma is formed of a boron carbide sintered body having a relative density of at least 96% and containing 300 ppm or below, in a total amount, of an alkali metal, an alkalin earth metal and a transition metal, and a process for producing the same.