Method of manufacturing semiconductor device having plural transistors formed in well region and semiconductor device

摘要

A first transistor and a second transistor are formed in a first element formation region, and a third transistor is formed in a second element formation region. The three transistors are of the same conductive type, and the first transistor and the second transistor have the same threshold voltage. A first well is formed in the first element formation region by use of a first mask pattern, and a second well is formed in the second element formation region by use of a second mask pattern. A channel region of the first transistor and a channel region of the second transistor have a shape which is line-symmetrical with respect to a reference line. The first mask pattern has a shape which is line-symmetrical with respect to the reference line.