| 摘要 |
PURPOSE:To obtain an accurate active region as designed, by providing a protruding part at each outer corner part, using an exposure mask having an active region pattern, in which each inner corner part has a slant side, and patterning an oxidation mask layer. CONSTITUTION:On a semiconductor substrate 31, a pad SiO2 film 32 and an Si3N4 film 33 are laminated and formed. This part is patterned by photolithography using an exposure mask 41. Only an active region forming area is made to remain. The exposure mask 41 is formed so that protruding parts 43 are formed at the outer corner parts of an active-region forming pattern 42 and the inner corner parts become slant sides 44. Therefore, Si3N4 film patterns 33a are formed in an L shape or a T shape, which has the protruding parts 34 and slant sides 35. With the Si3N4 film patterns 33a as masks, the device is oxidized in a steam atmosphere. Thus a field oxide film 36, in which right angles are maintained at the corners of the Si3N4 film patterns 33a, is formed. |
