Method for manufacturing semiconductor device, and semiconductor device

A semiconductor device, comprising:

• a semiconductor substrate;
• a first MISFET having a channel of a first conduction type and formed on the semiconductor substrate;
• a second MISFET having a channel of a second conduction type that is opposite to the first conduction type and formed on the semiconductor substrate;
• an isolation region between the first MISFET and the second MISFET;
• a first film having a first strain, the first film covering a region where the second MISFET is disposed but not a region where the first MISFET is disposed;
• a second film having a second strain whose type is opposite to a type of the first strain, the second film covering the region where the first MISFET is disposed but not the region where the second MISFET is disposed;
• and
• an interlayer insulating film disposed on the first film and the second film;
• and
• a conductive plug extending through the interlayer insulating film over the isolation region;
• wherein the second film includes a first portion which has a first thickness, a second portion which is provided over the isolation region at a side closer to the second MISFET and has a second thickness being thinner than the first thickness, and a third portion which is provided over the first film and the isolation region,
• wherein the first film includes a fourth portion which has a third thickness being thicker than the second thickness.