Method and structure for semiconductor mid-end-of-line (meol) process

Abstract

A method of forming a semiconductor device provides a precursor that includes a substrate having first and second regions, wherein the first region includes an insulator and the second region includes source, drain, and channel regions of a transistor. The precursor further includes gate stacks over the insulator, and gate stacks over the channel regions. The precursor further includes a first dielectric layer over the gate stacks. The method further includes partially recessing the first dielectric layer; forming a second dielectric layer over the recessed first dielectric layer; and forming a contact etch stop (CES) layer over the second dielectric layer. In an embodiment, the method further includes forming gate via holes over the gate stacks, forming source and drain (S/D) via holes over the S/D regions, and forming vias in the gate via holes and S/D via holes.