Polish to remove topography in sacrificial gate layer prior to gate patterning

Abstract

Techniques are disclosed for fabricating FinFET transistors (e.g., double-gate, trigate, etc). A sacrificial gate material (such as polysilicon or other suitable material) is deposited on fin structure, and polished to remove topography in the sacrificial gate material layer prior to gate patterning. A flat, topography-free surface (e.g., flatness of 50 nm or better, depending on size of minimum feature being formed) enables subsequent gate patterning and sacrificial gate material opening (via polishing) in a FinFET process flow. Use of the techniques described herein may manifest in structural ways. For instance, a top gate surface is relatively flat (e.g., flatness of 5 to 50 nm, depending on minimum gate height or other minimum feature size) as the gate travels over the fin. Also, a top down inspection of gate lines will generally show no or minimal line edge deviation or perturbation as the line runs over a fin.