| 摘要 |
PURPOSE:To reduce excessive selective oxidation in the lateral direction by introducing N<+> or C<+> through ion implantation to the neighborhood of pattern edge of oxidation preventing film and thereby forming an oxidation preventing region in a semiconductor substrate. CONSTITUTION:An SiN 2 is patterned as the oxidation preventing film on the lower SiO2 1 with the resist 3 used as a mask. Next, the P-SiO2 5 is deposited at a low temperature and the P-SiO2 5 is partly etched with a fluoric acid system etchant. Since the etching rate is large only at the stepped portion, a part (aperture) 6 having no P-SiO2 5 is accurately formed by the self alignment method at the edge of SiN pattern. Thereafter, with the remaining P-SiO2 5 used as the mask, N<+> or C<+> ion is implanted from the aperture 6 and thereby the implanted layer 7 is formed as the oxidation preventing region. Next, the P-SiO2 5 used as the mask, resist 3 and lower oxide film 1 are removed and a field oxide film 8 is formed after the heat processing. |
