Dry etching process for bulk finFET manufacturing
This paper describes a method to manufacture bulk fins for finFET. The bulk fins consist of two parts: the straight top of 125nm height which is used as a fin and a sloped bottom of 200nm one that facilitates the trench filling. The method is based on a conventional shallow trench isolation (STI) process flow with an additional ?-C hard mask of 90nm (with antireflective SiOC coating of 35nm) on top of the STI stack (70nm nitride on top of 8nm oxide). The nitride layer and the top straight part of the fin is patterned using CH2F2/SF6/N2 chemistry and ?-C as a mask, while the bottom sloped part is patterned using Cl2/O2/N2 chemistry and the nitride layer as a mask. After the etching, the STI process flow remains almost unchanged.
dry etching bulk finfet