| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device of a twin-well structure, of which reliability is improved by shalllowly forming wells under a gate electrode structure. SOLUTION: A thick-film resist pattern 7a and a thin-film resist pattern are formed through the same exposure process, using a reticle having a semi- transmitting area 6a, comprising a plurality of light-proof areas (lines) and light-transmitting areas (spaces) with dimensions smaller than the critical resolving power of the exposure system. To form wells, impurity ions are implanted by transmission of light through a thin film resist pattern 7b. Consequently, a shallow p-well is formed in the thin-film resist pattern 7b, and impurity ion implantation to the lower layer of the thick-film resist pattern 7a is prevented. |
