| 摘要 |
PURPOSE:To form element isolation region with good accuracy in such a height as almost equal to the semiconductor substrate surface by selectively remaining semiconductor film within the recessed part where becoms the element isolation region without depending on a pattern width of recessed part. CONSTITUTION:An SiO2 film 11, PSG film 12, and an Si3N4 film 13 are formed on a P type Si substrate 10. A recessed part 15 is formed by etching, an SiO2 film 17 is formed by thermal oxidation method, the Si3N4 film 13 is removed by etching, and a poly-Si film 18 is formed and finally heat treatment is also conducted. The poly-Si film 18a, PSG film 12 and the SiO2 film 11 are removed by etching, an SiO2 film 19 is formed by the oxidation to the entire part. Thereby, an element isolating region having the surface of poly-Si film 18 which is almost equal in height to the surface of substrate 10 can be formed. Thereby, difference of etching rate between the poly-Si film 18a where phosphorus is diffused and the poly-Si film 18 where phosphorus is not diffused becomes large and the poly-Si film 18 can selectively be left in the recessed part 15. |
