METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

A method for manufacturing a semiconductor device is provided. The method includes etching a dummy gate to form a gate trench to expose a channel portion of a first fin and a first isolation structure; depositing a gate dielectric layer and first and second work function layers, wherein the second work function layer has a first portion directly over the channel portion of the first fin and a second portion directly over the first isolation structure; etching the second portion of the second work function layer, wherein the first portion of the second work function layer remains; depositing a third work function layer over and in contact with the first portion of the second work function layer and the first work function layer; and filling the gate trench with a gate metal.