Methods for forming a semiconductor device and a FinFET device are disclosed. A method comprises forming a dummy gate electrode layer over a substrate, the dummy gate electrode layer having a first height, forming a first etch stop layer on the dummy gate electrode layer, forming a first hard mask layer on the first etch stop layer, and patterning the first hard mask layer. The method further comprises patterning the first etch stop layer to align with the patterned first hard mask layer, and patterning the gate electrode layer to form a dummy gate electrode, the dummy gate electrode aligning with the patterned first etch stop layer, wherein after the patterning the gate electrode layer the first hard mask layer has a vertical sidewall of a second height, the second height being less than the first height, and the first hard mask layer having a rounded top surface.