| 摘要 |
PROBLEM TO BE SOLVED: To form a high resistance protective film on an upper layer of high resistance parts of high resistance elements, without increasing the process of forming photoresist masks. SOLUTION: The method comprises step (A) for forming a resistance element polysilicon film 5, a silicon oxide film 7, a protective polysilicon film 9, a silicon oxide film 11 and a photoresist mask 13 on a semiconductor substrate 1, in this order, step (B) for forming a laminate pattern 15 composed of the silicon oxide film 7, the polysilicon film 9 and the silicon oxide film 11, using the mask 13, introducing an impurity in the polysilicon film 5 to form low resistance parts 5b, using the laminate pattern 15 as a mask, which results in high resistance parts 5a from the polysilicon film 5 beneath the laminate pattern 15, and step (C) for forming a silicon oxide film 17 on the low resistance parts 5b and the side of the polysilicon film 9 and (D-F) for patterning the high resistance parts 5a and the low resistance parts 5b, using a photoresist mask 19.
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