Abstract: A method for manufacturing a corrosion resistant member that includes a substrate including a ceramic or a metal, and at least one layer of a corrosion resistant film formed on a surface of at least a region of the substrate to be exposed to plasma or a corrosive gas. The corrosion resistant film contains yttria as a main component and further contains at least one of tantalum and niobium in an amount of 0.02 mol % to 10 mol % in terms of pentoxide relative to the yttria, and a non-melted portion is not present in the corrosion resistant film. The method includes mixing a raw material powder of yttria with a raw material powder of at least one of a tantalum oxide and a niobium oxide, followed by granulating the raw material powders to obtain a granulated powder.

Abstract: The present invention relates to a corrosion resistant member including: a substrate composed of a ceramic or a metal, and at least one layer of a corrosion resistant film formed on a surface of at least a region of the substrate to be exposed to plasma or a corrosive gas, in which the corrosion resistant film contains yttria as a main component and further also contains at least one of tantalum and niobium in an amount of 0.02 to 10 mol % in terms of pentoxide relative to the yttria, and a non-melted portion is not present in the corrosion resistant film.

Abstract: The present invention provides ceramics for a plasma-treatment apparatus which are excellent in corrosion resistance against a halogen-type corrosive gas, plasma, etc., attain reduction in resistance, and inhibit impurity metal contamination caused by composition materials of these ceramics even in a halogen plasma process, and which can be used suitably for the component of the plasma-treatment apparatus for manufacturing a semiconductor, a liquid crystal, etc. The ceramics are used which are prepared in such a way that 3% by weight to 30% by weight of a cerium oxide relative to yttria and 3% by weight to 50% by weight of niobium pentoxide relative to yttria are added to yttria, which are fired in a reducing atmosphere to have an open porosity of 1.0% or less.

Abstract: The present invention aims to provide a sintered body and a component used in a plasma processing apparatus. The sintered body and the component are mainly composed of a cerium oxide, which is excellent in corrosion resistance to halogen-based gas or plasma, and can reduce resistance. The cerium oxide can also suppress contamination of metal due to impurity caused by the constituent material of the ceramic even in a halogen plasma process, so that it can preferably be used, as a substitute of an yttria, for a component in a plasma processing apparatus for manufacturing a semiconductor or liquid crystal. A sintered body is used, wherein at least the portion exposed to plasma is formed by adding an yttria with a purity of 99% or more in an amount of 3 parts by weight or more and 100 parts by weight or less to 100 parts by weight of a cerium oxide having purity of 99% or more. Alternatively, a component covered by a sprayed film having the composition same as described above is used.

Abstract: To provide an inexpensive gas dispersion plate having a high corrosion resistance to halogen-based corrosive gasses and a plasma thereof, and capable of preventing particle generation from the gas hole, thereby contributing to an improvement in the production yield of the semiconductor devices. The gas dispersion plate includes one or plural gas holes in a base material formed by a Y2O3 ceramic material having a relative density of 96% or more, in which an edge part of the gas hole is formed by a sand blasting process into a rounded shape with a radius of curvature of 0.2 mm or more.

Abstract: A method for casting Y2O3 has steps of adding an acid to a slurry comprising at least a ceramic material having a purity of an Y2O3 being 99 wt % or more with an average particle diameter of 2 &mgr;m or less, water, a binder and a dispersant so that a pH value can be adjusted ranging from 8.5 to 10.5 and injecting the slurry into a mold.

Abstract: A heating soft floor mat is described comprising a base sheet composed of a thermoplastic resin foamed article as a heat insulating layer having meanderingly formed thereon grooves for conduits, conduits for heating medium disposed in the grooves, and cover material having flexibility covering the surface side thereof, wherein the thermoplastic resin foamed article is a crosslinked polyethylene foamed article containing closed cells having a degree of expansion of from 10 to 40 and the conduits are composed of low density crosslinked polyethylene having a density of less than 0.910 g/cm.sup.3.