Metal wet etch process development for dual metal gate CMOS

Abstract

Wet etch chemistries using standard chemicals and tools available in the industrial clean room have been studied to successfully integrate dual work function metal gate complementary metal oxide semiconductor (CMOS). Candidate gate materials included TiN, Ta, TaN, TaCN, TaSiN, and TiSiN deposited by atomic layer deposition (ALD), physical vapor deposition, and chemical vapor deposition. A plasma enhanced tetraethylorthosilicate hard mask and two gate dielectric films, ALD-based HfO2 and HfSixOy, were also studied for their etch selectivity to various chemical formulations. In addition, preliminary electrical results of capacitor devices processed using these wet etch processes are reported. © 2005 The Electrochemical Society. All rights reserved.