Patent ID: 7641761

Claim:
A showerhead configured to be provided in a plasma CVD apparatus, comprising: a cylindrical body having a hollow structure with an annular peripheral-edge surface; and a shower plate having a number of fine pores, wherein the shower plate is detachably integrated with the body at a contact area of the peripheral-edge surface of the body, wherein the contact area is in contact with a peripheral surface of the shower plate, wherein both the body and the shower plate are constituted by substantially the same aluminum alloy, wherein the contact area of the peripheral-edge surface of the body, rather than all other surfaces of the body, contacts the peripheral surface of the shower plate and is covered with an anodic oxide coating formed predominantly on the peripheral-edge surface relative to all other surfaces of the body, said coating being such that the coating does not prevent the passage of electric current or propagation of radio-frequency waves.