COATING FILM EXCELLENT IN CORROSION RESISTANCES TO HALOGEN GAS AND HALOGEN PLASMA, AND LAMINATED STRUCTURE FORMED WITH THE COATING FILM

摘要

PROBLEM TO BE SOLVED: To enable the composition of a coating film showing excellent corrosion resistances to halogen gases and plasma by regulating the content of Si base substance as impurities to specified one or below. SOLUTION: This coating film is composed of an Al oxide thin film. The content of Si base substance contained as impurities in the thin film layer is regulated to <=5wt.%, preferably to <=1wt.% expressed in terms of Si. The size of the Si base substance is regulated to <=0.5μm, preferably to <=0.1μm. The area ratio of the ununiformed part observed in the region of 30×50 (μm) in the nonetched zone appeared on the surface by etching is regulated to <=10%, preferably to <=5%. The thickness of the film is preferably regulated to 1 to 20μm. The why-reason originates from that which an Al2 O3 film excellent in corrosion resistance to halogen plasma is dense and amorphous, and the uniformity of amorphousness is the important key factor for its corrosion resistance. Thus, the coating film showing excellent corrosion resistance to halogen plasma can be provided.