Patent ID: 7737048

Claim:
A method for designing a thickness distribution of an oxide film formed by using a combination of a first oxidation process forming a first portion of the oxide film and a subsequent second oxidation process for forming a second portion of the oxide film which is disposed on the first portion of the oxide film, wherein the first oxidation process and the second oxidation process have different process conditions thereby achieving different in-plane thickness distributions, said method comprising the steps of: determining a time length of the second oxidation process to compensate for a variation of in-plane thickness of the first portion of the oxide film to be formed by the first oxidation process; calculating a thickness of the first portion of the oxide film based on a predetermined final film thickness of the oxide film, the time length for forming the second portion of the oxide film determined by said determining step, and an oxidation rate of the second oxidation process; and obtaining a time length of the first oxidation process needed for forming the first portion of the oxide film having the thickness calculated by said calculating step based on an oxidation rate of the first oxidation process.