REMOVAL OF NITRIDE BUMP IN OPENING REPLACEMENT GATE STRUCTURE

摘要

Methods for opening polysilicon NFET and PFET gates for a replacement gate process are disclosed. Embodiments include providing a polysilicon gate with a nitride cap; defining PFET and NFET regions of the polysilicon gate, creating a nitride bump on the nitride cap; covering the nitride cap to a top of the nitride bump with a PMD; performing a 1:1 dry etch of the PMD and the nitride bump; and performing a second dry etch, selective to the nitride cap, down to the top surface of the polysilicon gate. Other embodiments include, after creating a nitride bump on the nitride cap, recessing the PMD to expose the nitride cap; covering the nitride cap and the nitride bump with a nitride fill, forming a planar nitride surface; and removing the nitride fill, nitride bump, and nitride cap down to the polysilicon gate.

主权项

1. A method comprising:
providing a polysilicon gate with a nitride cap on a top surface thereof; defining PFET and NFET regions of the polysilicon gate, creating a nitride bump on a top surface of the nitride cap; covering the nitride cap to a top of the nitride bump with a pre-metal dielectric (PMD); performing a first dry etch comprising a 1:1 dry etch of the PMD and the nitride bump; and performing a second dry etch, selective to the nitride cap, down to the top surface of the polysilicon gate.