| 摘要 |
PURPOSE:To increase the density of a semiconductor device, and to reduce a photoetching process to one time by adjacently forming a P-type well region and an N-type well region. CONSTITUTION:An silicon oxide film 13 and an silicon nitride film 14 functioning as an oxidation-resistant mask are shaped onto a single crystal silicon substrate 12. A window for forming an N-type well region is bored through etching, using a resist 17 shaped by applying, exposing and etching a resist 16 as a mask, and ions 18 forming an N type are implanted, employing the silicon nitride film 16 and the resist 17 as masks to shape an N-type well region 19. when an silicon oxide film 20 is formed through selective oxidation, using the silicon nitride film 16 as a mask and the silicon nitride film is removed through etching, an silicon oxide film 21 in a selectively oxidized section is left. Ions 22 shaping a P type are implanted, employing the silicon oxide film 21 as a mask, and a P-type well region 23 is formed adjacently to the N-type well region 19. |
