A member for a plasma etching device, which comprises a device substrate comprising quartz glass, aluminum, alumite or a combination thereof and, formed on the surface thereof, a coating film of yttrium oxide or YAG having a film thickness of 10 .mu.m or more and a variation in the thickness of 10% or less, and preferably a surface roughness (Ra) of 1 .mu.m or less; and a method for manufacturing the member for a plasma etching device, which comprises a step of plasma-spraying yttrium oxide or YAG to the surface of said device substrate or a step of fusing yttrium oxide or YAG with an oxyhydrogen flame, followed by coating the surface with the fused product, or a step of applying a solution containing yttrium, a yttrium compound or YAG on the above surface, followed by heating to fuse the resultant coating, or a combination of the above steps, thereby forming a coating film of yttrium oxide or YAG having a film thickness 10 .mu.m or more and a variation in the thickness of 10% or less, and preferably a surface roughness (Ra) of 1 .mu.m or less. The member for a plasma etching device is capable of retaining high plasma resistance for a long period of time, is free from the occurrence of the abnormal etching owing to partial change of electric characteristics, and thus can be used for a long time, in particular, even in the treatment of a large semiconductor device of a 12 inch silicon wafer.

Claims data not available