Method to form wrap-around contact for finFET

摘要

Embodiments of the present invention provide an improved contact formation process for a finFET. Epitaxial semiconductor regions are formed on the fins. A contact etch stop layer (CESL) is deposited on the epitaxial regions. A nitride-oxide conversion process converts a portion of the nitride CESL into oxide. The oxide-converted portions are removed using a selective etch process, and a fill metal is deposited which is in direct physical contact with the epitaxial regions. Damage, such as gouging, of the epitaxial regions is minimized during this process, resulting in an improved contact for finFETs.

主权项

1. A method of forming a semiconductor structure comprising:
forming a semiconductor fin on a semiconductor substrate; forming an epitaxial semiconductor region disposed on the semiconductor fin; forming a nitride contact etch stop layer on the semiconductor fin; depositing a blanket oxide layer on the semiconductor fin; performing a first anisotropic etch on the blanket oxide layer over the semiconductor fin to form a cavity; performing a first isotropic etch on the blanket oxide layer over the semiconductor fin; depositing a conformal oxide layer on the nitride contact etch stop layer; performing a second anisotropic etch on the blanket oxide layer over the semiconductor fin; performing a nitride-oxide conversion process; performing a second isotropic etch on the conformal oxide layer; and depositing a fill metal in the cavity.