Patent ID: 9275840
Filing Date: 2016-03-01
CPC Classification: B05D,C23C,H01J,Y10T

Claim Text:
1. A method for providing uniform distribution of plasma density in a CCP plasma processing apparatus, the method comprising the steps of: providing a showerhead-cooler system of a semiconductor-processing chamber of the CCP plasma processing apparatus for plasma processing of objects, the system comprising a showerhead having a plurality of through gas holes and a gas-feeding cooler plate that is connected to an RF power supply, has an electric contact with the showerhead and forms with the showerhead a gas accumulation reservoir, one ends of the gas holes being connected to the gas accumulation reservoir, and the other ends of the gas holes being connected to semiconductor-processing chamber, the gas-feeding cooler plate being connected to a source of a working gas and has a plurality of through gas feeding passages that communicate with the gas accumulating reservoir, the shower head having a central area and a peripheral portion; forming on said one ends of at least some of the through gas holes conical nozzles with a cone angle θ that decreases in the direction from the peripheral portion to the central area of the showerhead in the range from 120° to 0°; and coating the surfaces of the conical nozzles and at least a part of the walls of the gas holes in the area adjacent to the conical nozzles with a protective coating resistant to electrical breakdown and chemical corrosion.