SELF-ALIGNED TRENCH OVER FIN

摘要

A stack of a first hard mask portion and a second hard mask portion is formed over a semiconductor material layer by anisotropically etching a stack, from bottom to top, of a first hard mask layer and a second hard mask layer. The first hard mask portion is laterally recessed by an isotropic etch. A dielectric material layer is conformally deposited and planarized. The dielectric material layer is etched employing an anisotropic etch that is selective to the first hard mask portion to form a dielectric material portion that laterally surrounds the first hard mask portion. After removal of the second and first hard mask portions, the semiconductor material layer is etched employing the dielectric material portion as an etch mask. Optionally, portions of the semiconductor material layer underneath the first and second hard mask portions can be undercut at a periphery.

主权项

1. A method of forming a semiconductor structure comprising:
forming a vertical stack, from bottom to top, of a first hard mask portion laterally surrounded by a dielectric material portion and a second hard mask portion over a semiconductor material layer, wherein outer sidewalls of said dielectric material portion are vertically coincident with sidewalls of said second hard mask portion; removing said second hard mask portion and said first hard mask portion selective to said dielectric material portion; and patterning said semiconductor material layer into a semiconductor fin by anisotropically etching said semiconductor material layer employing said dielectric material portion as an etch mask.