To reduce abnormal discharge under a ceiling plate by forming a uniform distribution of a gas spouted to a face of a substrate, reduce a load on the ceiling plate, and make it easy to form the ceiling plate.
A substrate 9 is treated while a gas is fed with a uniform distribution from a gas spouting hole 11 in a first ceiling plate 10 after the gas is passed through a gas flowing path 2 made up of one or a plurality of linear grooves passing a point in the first ceiling plate 10 and formed in the first ceiling plate 10 and an arcuate groove with a center of a cross point that crosses the linear groove. In this way, there is no gap for storing the gas between the first and second ceiling plates 10 and 12 to eliminate a fear of abnormal discharge. At the same time, gas pressure on the second ceiling plate 12 is limited, and the gas spouting hole 11 is aligned in position with an arcuate groove of the second gas path 2, so a tolerance of dimensions in an angle direction at manufacturing can be enlarged.
HARAGUCHI HIDEO
MATSUDA IZURU
OKUMURA TOMOHIRO
MIHASHI AKIO
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