Patent ID: 7897009

Claim:
A plasma processing apparatus comprising: a process chamber configured to perform a plasma process on a target substrate, the process chamber including a chamber casing that defines a surrounding sidewall and a microwave transmission plate consisting of a dielectric body and airtightly closing a ceiling portion of the chamber casing; a substrate worktable disposed inside the chamber casing and configured to place the target substrate thereon; a gas supply system configured to supply a process gas into the process chamber; an exhaust system configured to decrease pressure inside the process chamber; a planar antenna disposed outside the microwave transmission plate in parallel with the microwave transmission plate and having a plurality of slots, from which microwaves are supplied into the process chamber through the microwave transmission plate to generate plasma; and a wave guide tube connected to a center of an upper side of the planar antenna from above and configured to guide the microwaves generated in a microwave generation unit to the planar antenna, wherein the chamber casing includes an annular support portion formed integrally with the surrounding sidewall and extending inward from the surrounding sidewall, such that the annular support portion is defined by a lower face inclined inward and upward from the surrounding sidewall, a rising face extending upward from an inner end of the lower face, and a supporting upper face equipped with a plurality of step portions and inclined outward and upward as a whole from an upper end of the rising face, the microwave transmission plate includes an engaging face formed on a peripheral side and equipped with a plurality of step portions having complementary shapes relative to the plurality of step portions of the supporting upper face of the annular support portion, such that the microwave transmission plate is supported by the chamber casing through the engaging face fitted on the supporting upper face, and the microwave transmission plate further includes a covering portion formed integrally therewith and extending downward from a position on an inner side of the engaging face, such that the covering portion protrudes down to the inner end of the lower face of the annular support portion and covers the rising face of the annular support portion; wherein the rising face of the annular support portion is within an area defined between the microwave transmission plate and a position 22-mm distant therefrom.