A method for fabricating semiconductor device first includes providing a substrate and a shallow trench isolation (STI) in the substrate, in which the substrate includes a first metal gate and a second metal gate thereon, a first hard mask on the first metal gate and a second hard mask on the second metal gate, and a first interlayer dielectric (ILD) layer around the first metal gate and the second metal gate. Next, the first hard mask and the second hard mask as mask are utilized to remove part of the first ILD layer for forming a recess, and a patterned metal layer is formed in the recess and on the STI.