Patent ID: 8343308
Filing Date: 2013-01-01
Classification: C23C,H01J,H01L,H05H,Y10T

Abstract:
1. A ceiling plate that is provided at a ceiling portion of a process chamber that may be evacuated to a vacuum, wherein the ceiling plate allows microwaves emitted from a plurality of slots of a planar antenna member provided along with the ceiling plate to pass through the ceiling plate into the process chamber, the ceiling plate comprising: plural concave portions arranged along a circle in a surface of the ceiling plate so as to form plural radially disposed virtual convex portions in a plane between the concave portions, the surface facing toward an inside of the process chamber, wherein the plural concave portions have a circular top view shape, wherein a thickness of places where the concave portions are formed in the ceiling plate and another thickness of other places where the concave potions are not formed in the ceiling plate are determined so that the number of propagation modes of microwaves is different in the places where the concave portions are formed from the number of propagation modes in the other places where the concave portions are not formed, and wherein a plurality of pairs of the slots are concentrically arranged in the planar antenna member, and the number of the virtual convex portions of the ceiling plate is equal to the number of the pairs of the slots arranged along an inner circle among the plurality of pairs of the slots arranged concentrically.