A method for fabricating a semiconductor device is disclosed. The method includes providing a substrate; forming one or more gate structures over the substrate; forming a buffer layer over the substrate, including over the one or more gate structures; forming an etch stop layer over the buffer layer; forming a interlevel dielectric (ILD) layer over the etch stop layer; and removing a portion of the buffer layer, a portion of the etch stop layer, and a portion of the ILD layer over the one or more gate structures.