| 摘要 |
Provided are a semiconductor device that optimizes the operation characteristics such as of both an insulating gate type transistor for high voltage and an insulating gate type transistor for low voltage, and a method of manufacturing the same. Specifically, a patterned resist (25) is formed so as to cover a low voltage operation region (A2), a second LDD implantation process of implanting an impurity ion (14) by using the resist (25) as a mask, is performed over a silicon oxide film (6) thereby to form an impurity diffusion region (13) in the surface of a semiconductor substrate (1) in a high voltage operation region (A1). After this step, the silicon oxide film (6) in the high voltage operation region (A1) contains the impurity during the second LDD implantation process whereas the silicon oxide film (6) in a low voltage operation region (A2) contains no impurity. This leads to such a characteristic that in the following pre-treatment with a wet process, the silicon oxide film (6) containing the impurity in the high voltage operation region (A1) is reduced in thickness, and the silicon oxide film (6) containing no impurity in the low voltage operation region (A2) is not reduced in thickness.
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