Replacement gate with TERA cap

摘要

A field effect transistor formed by a sacrificial gate process has a simplified process and improved yield by using a tunable resistant anti-reflective coating (TERA) as the cap layer over the sacrificial gate layer. The TERA layer serves as a tunable anti-reflection layer for photolithography patterning, a hardmask for etching the sacrificial gate, a polish stopping layer for planarization, and a blocking layer for preventing silicide formation over the sacrificial gate. The TERA is stripped by a two-step process that is highly selective to the nitride spacers, so that the spacers are not damaged in the process of stripping the sacrificial gate.