Replacement metal gate transistors using bi-layer hardmask

摘要

Methods of fabricating replacement metal gate transistors using bi-layer a hardmask are disclosed. By utilizing a bi-layer hardmask comprised of a first layer of nitride, followed by a second layer of oxide, the topography issues caused by transition regions of gates are mitigated, which simplifies downstream processing steps and improves yield.

主权项

1. A method of fabricating a replacement metal gate transistor, comprising:
depositing a dummy gate,
wherein the dummy gate comprises
an N-type region,a P-type region, anda transition region; depositing a bi-layer
over the dummy gate,wherein the bi-layer comprises
a first sub-layer comprised of nitride, anda second sub-layer comprised of a first oxide layer; depositing a conformal nitride layer over the dummy gate; forming a first set of spacers
adjacent to the dummy gatein the N-type region; forming a second set of spacers
adjacent to the dummy gatein the P-type region; depositing a second oxide layer to cover the bi-layer, the first set of spacers, and the second set of spacers; planarizing the second oxide layer to leave a remaining portion with a height at the level of the top of the conformal nitride layer; and recessing the second oxide layer to the level of the first sub-layer of nitride.