GAS DISTRIBUTION APPARATUS FOR SEMICONDUCTOR PROCESSING

摘要

A gas distribution system for uniformly or non-uniformly distributing gas across the surface of a semiconductor substrate. The gas distribution system includes a support plate (20) and a showerhead (22) which are secured together to define a gas distribution chamber (24) therebetween. A baffle assembly (26) including one or more baffle plates is located within the gas distribution chamber. The baffle arrangement includes a first gas supply (40) supplying process gas to a central portion (42) of the baffle chamber and a second gas supply (44) supplying a second process gas to a peripheral region (46) of the baffle chamber. Because the pressure of the gas is greater at locations closer to the outlets of the first and second gas supplies, the gas pressure at the backside of the showerhead can be made more uniform than in the case with a single gas supply.