Patent ID: 8757090

Claim:
A gas shower plate for use with a plasma processing apparatus, for feeding out a plasma-generation gas supplied from a gas supply portion to a plasma processing space defined between an upper electrode and a lower electrode of the plasma processing apparatus, the shower plate comprising: a porous plate having gas permeability, which is formed of a sintered body of ceramic particles, the plate having a plurality of cutout portions which are formed in an outer edge portion of the plate so as to extend through the plate in a thicknesswise direction thereof and which serve for absorption of thermal expansion of the plate, wherein: the porous plate has a disc-like shape, the plate having a support region which is an annular region located in an outer edge portion of the disc-like shape and on which the plate is supported by the plasma processing apparatus, and a gas passage region which is a circular region located inside the outer edge portion of the disc-like shape and surrounded by the support region and in which the plasma-generation gas is allowed to pass therethrough, each of the cutout portions is formed in the support region so as to be in close proximity to a boundary with the gas passage region, and the cutout portions are formed only in the outer edge portion of the plate, and the support region being a region that is unexposed to plasma generated in the plasma processing space.