| 摘要 |
PURPOSE:To enable to perform an element isolation at a smaller conversion difference of pattern than in a selective oxidation method by a method wherein a polycrystalline silicon film is utilized as a coated film, whose volume expands by performing an oxidation. CONSTITUTION:A polycrystalline silicon pattern 14' and a second Si3N4 pattern 15' are formed on an Si substrate 11 through an SiO2 film 12 and a first Si3N4 film 13, and after that, by performing an oxidation treatment on the polycrystalline silicon pattern 14' exposing from the aperture part 16 of the second Si3N4 pattern 15', a thermal oxide film 18 is formed. By this manner, the aperture diameter L2 of the aperture part 17 of the thermal oxide film 18 can be made narrower than the aperture diameter L1 of the aperture part 16 of the second Si3N4 pattern 15'. As a result, the Si3N4 film 13 can be removed by performing an etching using such the thermal oxide film 18 as a mask, thereby enabling to form an Si3N4 pattern 13', which is narrower than the resist pattern. |
