| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor device by which an gate electrode can be formed without any damage to a semiconductor substrate, even if polysilicon layers having different etching rates are etched at the same time. SOLUTION: The first polysilicon layer 17a of the semiconductor device 11 doped with impurities and an undoped second polysilicon layer 20a are formed on a silicon substrate 12. Next, a mask 36 made of a silicon oxide film is formed on the first polysilicon layer 17a with the help of a difference in film thickness of an oxide film depending on the concentration of impurities in the first and second polysilicon layers 17a and 20a. Then, the mask 36 is used to etch the second polysilicon layer 20a. Thus, the second polysilicon layer 20a is etched at such film thickness that etching rates for the first and second polysilicon layers 17a and 20a may become the same mutually and substantially. COPYRIGHT: (C)2007,JPO&INPIT
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