Abstract: A dense cordierite based sintered body contains 93% by mass or more of cordierite among crystal components contained in the sintered body, and an average particle diameter of the particle which constitute the sintered body is 2 ?m or less. A method of manufacturing a dense cordierite based sintered body, includes the steps of: using cordierite powder having an average particle diameter of 2 ?m or less as a raw material; and sintering the raw material at a temperature of 1350 to 1450° C. The dense cordierite based sintered body satisfactorily exhibits original characteristics of cordierite, and a sufficient strength.

Abstract: An object of the present invention is to provide a ceramic chuck for mounting a wafer so that the number of particles adhered onto the wafer after chucking can be reduced while maintaining a desired Young's Modulus of the chuck. A ceramic chuck 1 has a surface layer 2 contacting a wafer “W” and a substrate portion 6. The surface layer 2 and substrate portion 6 are produced by co-sintering and the surface layer 2 has a porosity of 1% or higher and 10% or lower and larger than that of the substrate portion 6.

Abstract: A fuel cell system is disclosed as having a water storage device 2 whose inside is provided with two partition walls 9, 10 to divide the same into three regions R1, R2, R3, and among these, a middle region R2 is provided with a water guide pipe 11 and a water return pipe 12 through which water is taken out or returned to the region R2. The partition walls 9, 10 have communicating bores 13a1, 13a2 through which water flow is admitted.

Abstract: A fuel cell system is disclosed as having a water storage device 2 whose inside is provided with two partition walls 9, 10 to divide the same into three regions R1, R2, R3, and among these, a middle region R2 is provided with a water guide pipe 11 and a water return pipe 12 by which water is taken out of or returns to the region R2. Provided on the partition walls 9, 10 are communicating mechanisms 13 through which adjacent regions are brought into fluid communication. The communicating mechanisms 13 have structures that are operative to permit water to be taken out of or to be returned to the region R2 while blocking outflow of water from the region R2 to the other regions R1, R3.

Abstract: An aluminum nitride sintered body includes a polycrystalline structure in which grain boundary fracture toughness KICgb is 1.6 MPa·m1/2 or more. The grain boundary fracture toughness KICgb can be determined by the following equation: KICgb=KCIC·cos2(?·PIF/200) where KIC is fracture toughness (MPa·m1/2), and PIF is a percentage of the intergranular fracture (%).

Abstract: An aluminum nitride sintered body containing carbon fibers is provided. This aluminum nitride sintered body is obtained by mixing carbon fibers and aluminum nitride together to form mixed powder, molding the mixed powder to form a compact, and heating and sintering the compact in any of a vacuum atmosphere, an inert atmosphere and a reductive atmosphere. By using electric conductivity and shapes with high aspect ratios of the carbon fibers, continuous electrically conductive paths are formed with a small content of the carbon fibers. In this way, a value of resistance of the aluminum nitride sintered body is reduced.

Abstract: An object of the present invention is to provide a novel aluminum nitride material of aluminum nitride base and having a low volume resistivity at room temperature. An aluminum nitride material has aluminum nitride as a main component and europium in a content of 0.03 mole percent or more calculated as the oxide, and the material has aluminum nitride and an europium-aluminum composite oxide phases. Alternatively, an aluminum nitride material has aluminum nitride as a main component and europium and samarium in a total content of 0.09 mole percent or more calculated as the oxides, and the material has aluminum nitride phase and a composite oxide phase containing at least europium and aluminum.

Abstract: An electrostatic chuck includes a substrate having a wafer-installing face and an opposed back face. An electrostatic chucking electrode is buried in the substrate, and an insulating layer is provided on the back face of the substrate. The substrate also includes a dielectric layer including at least the wafer-installing face and surrounding the electrostatic chucking electrode, and the insulating layer includes an insulating material having a larger volume resistivity than that of the dielectric layer.

Abstract: A wafer attracting apparatus includes a substrate made of a ceramic material and adapted to attract and hold a wafer onto an attracting surface thereof, wherein the attracting surface is constituted by a ductile worked surface, the ductile worked surface has concave portions, a diameter of each of the concave portions is 0.1 &mgr;m or less, and when the wafer is attracted onto the attracting surface of the substrate and released therefrom, the number of particles attaching to that wafer is 9.3 or less per 1 cm2.

Abstract: A gas feed ceramic structure for feeding a gas into a semiconductor-producing apparatus, includes a planar substrate having a gas-feeding surface and a rear surface. The planar substrate has depressions formed from the rear surface toward the gas-feeding surface to define thin portions between the depressions and the gas-feed surface. Each of the thin portions includes a plurality of gas feed holes for feeding the gas to a side of the gas-feeding surface of the substrate, and one open end of the gas feed holes is provided at the gas-feeding surface of the substrate, and the other open end faces the depressions.

Abstract: In a plasma processing apparatus, a temperature control of a substrate to be processed is improved. A ceramic made support member having a substantially cylindrical shape is provided in a process chamber. An upper end of the support member is airtightly connected to a back surface of a placement table by solid state bonding. A lower end of the support member is airtightly connected to a bottom of the process chamber via a lower cooling jacket and O-rings. A cooling jacket made of a disc-like aluminum block is provided in an atmosphere chamber formed inside the support member. The cooling jacket is mounted to the back surface of the placement table via a heat conductive sheet member.

Abstract: An electrostatic chuck includes a substrate having a wafer-installing face and a back face on an opposite side of the wafer-installing face, an electrostatically chucking electrode buried in the substrate, and an insulating layer provided at the back face of the substrate, the substrate including a dielectric layer facing at least the wafer-installing face and surrounding the electrostatically chucking electrode, and said insulating layer including an insulating material having a volume resistivity larger than that of the dielectric layer.

Abstract: A semiconductor wafer-holder having a member for holding the semiconductor wafer with a basic member made of a ceramic nitride, a cooling equipment made of a metal, and an intervened layer between the semiconductor wafer-holding member and the cooling equipment, the intervened layer being composed of a metallic foil or a carbon sheet having a thickness of not more than 500 &mgr;m.

Abstract: An aluminum nitride sintered body has characteristics such that an amount of total metal elements other than aluminum is smaller than 100 ppm, and a volume resistivity at room temperature is greater than 1.0×109 &OHgr;·cm and is smaller than 1.0×1013 &OHgr;·cm. A metal including member has such a construction that a metal member is embedded in the aluminum nitride sintered body mentioned above. An electrostatic chuck is made by the metal including member mentioned above. In the metal including member mentioned above in which the metal member is embedded in the aluminum nitride sintered body mentioned above, a volume resistivity thereof can be controlled without adding a low resistance material in aluminum nitride.

Abstract: A wafer attracting apparatus includes a substrate made of a ceramic material and adapted to attract and hold a wafer onto an attracting surface thereof, wherein the attracting surface is constituted by a ductile worked surface, the ductile worked surface has concave portions, a diameter of each of the concave portions is 0.1 .mu.m or less, and when the wafer is attracted onto the attracting surface of the substrate and released therefrom, the number of particles attaching to that wafer is 9.3 or less per 1 cm.sup.2.

Abstract: An electrostatic chuck for attracting an object for treatment. The electrostatic chuck includes a substrate, an insulating dielectric layer and at least one electrode located between the substrate and the insulating dielectric layer. The object is attracted onto the electrode via the insulating dielectric layer. The insulating dielectric layer is between 0.5 mm and 5.0 mm thick, and utilizes a gas-introducing hole to form a gas-diffusing depression on the side of an attractive surface, allowing for more uniform heat conduction. The gas-diffusing depression is between 100 um and 5.0 mm deep. The distance between the bottom surface of the gas-diffusing depression and an electrode may range from 500 .mu.m to 5 mm.

Abstract: An aluminum nitride sintered body has characteristics such that an amount of total metal elements other than aluminum is smaller than 100 ppm, and a volume resistivity at room temperature is greater than 1.0.times.10.sup.9 .OMEGA..multidot.cm and is smaller than 1.0.times.10.sup.13 .OMEGA..multidot.cm. A metal including member has such a construction that a metal member is embedded in the aluminum nitride sintered body mentioned above. An electrostatic chuck is made by the metal including member mentioned above. In the metal including member mentioned above in which the metal member is embedded in the aluminum nitride sintered body mentioned above, a volume resistivity thereof can be controlled without adding a low resistance material in aluminum nitride.

Abstract: An electrostatic chuck for attracting an object to be treated, includes a substrate, an insulating dielectric layer and at least one electrode provided between the substrate and the insulating dielectric layer, wherein the above object is to be attracted onto the electrode via the insulating dielectric layer and an average thickness of the insulating dielectric layer is not less than 0.5 mm and not more than 5.0 mm.

Abstract: A joined metal-ceramic assembly formed from a ceramic member and a metallic member which are butted and joined together with an intermediate layer interposed therebetween, wherein a joining surface of the ceramic member at which the ceramic member is joined with the intermediate layer includes a rounded peripheral portion which has a substantially arcuate cross sectional shape and the method of producing the metal-ceramic assembly.