METHOD FOR MAKING METAL GATE STACK STRUCTURE IN GATE FIRST PROCESS

摘要

A method for making the metal gate stack structure in gate first process is provided. After forming the conventional Local Oxidation of Silicon (LOCOS) and Shallow Trench Isolation (STI), the method comprising the following steps: growing a ultra-thin interfacial oxide or a nitrogen oxide layer on a semiconductor substrate using rapid thermal oxidation or chemical method; depositing a high dielectric constant (K) gate dielectric on the ultra-thin interfacial oxide layer, rapid thermal annealing after the deposition of the high K gate dielectric; depositing a TiN metal gate; depositing a AlN or TaN barrier layer; depositing a polysilicon (1) film and a SiO2 hard mask (2), and then carrying out the lithography and the etching of the SiO2 hard mask (2); and after removing the glue, etching the polysilicon (1) film/metal gate/high K gate dielectric layer in turn to form the metal gate stack structure. The method is suitable for the need of the high K gate dielectric/metal gate integration in nano-CMOS devices, and facilitates the achievement of high K gate dielectric/metal gate integration.