Semiconductor device and manufacture thereof

Abstract

Abstract PURPOSE:To reduce occurrence of stress on oxidation by using diffusion from BSG and PSG and using the BSG and PSG used for diffusion as a field oxide film. CONSTITUTION:A P-well 2 and an N-well 3 are already formed on a substrate 1, a BSG 10 and a CVDSiO2(1)11 are continuously accumulated to form a field oxide film within the P-well 2 and is etched leaving an isolating region, and then a PSG 12 and a CVDSiO2(2)13 are continuously accumulated to form the field oxide film of the N-well 3 and is etched leaving a separation area. A CVDSiO2(3)14 is accumulated over the entire surface for performing entire- surface etching and a side wall 15 is formed to prevent the PSG and BSG from becoming a diffusion source at areas except those needed and entering and reduction of film on etching from occurring. Also, since a channel stopper 9 is naturally diffused by the succeeding heat treating, after heat treatment is not required in many cases, thus eliminating oxidation process for a long time and reducing occurrence of stress which becomes a problem in the selection oxidation method, etc.

Inventors

• 👤 Hitoshi Kudo
• 👤 均 工藤

Bibliographic Details