Process method to fabricate cmos circuits with dual stress contact etch-stop liner layers

Abstract

Exemplary embodiments provide IC CMOS devices having dual stress layers and methods for their manufacture using a buffer layer stack between the two types of the stress layers. The buffer layer stack can include multiple buffer layers formed between a first type stress layer (e.g., a tensile stress layer) and a second type stress layer (e.g., a compressive stress layer) during the CMOS fabrication. Specifically, the buffer layer stack can be formed after the etching process of the first type stress layer but prior to the etching process of the second type stress layer, and thus to protect the etched first type stress layer during the subsequent etching process of the overlaid second type stress layer. In addition, a portion of the buffer layer stack can be formed between, for example, the compressive stress layer and the underlying PMOS device to enhance their adhesion.

Dependencies are inferred from the claim text.