Patent ID: 9589958
Date: 2017-03-07
CPC Classifications: H01L

Claim:
1. A method of forming a plurality of fins, the method comprising: forming a series of mandrels on a hard mask layer, which vertically overlays a semiconductor layer in contact with the hard mask layer, wherein the semiconductor layer is in an x-y direction; applying a conformal coating to form a spacer layer to produce sacrificial fins on the hard mask layer and the mandrels, wherein the sacrificial fins extend in a z-direction; removing the conformal coating from horizontal surfaces while retaining them on the sidewall of mandrels; removing the mandrels; etching into the hard mask material using the spacer sacrificial fin as a mask; covering desired sacrificial fins with a mask; removing an undesired sacrificial fin; applying a conformal coating to build a total thickness of the sacrificial fin and conformal coating equal to critical dimension and etchback allowance, wherein the critical dimension and the etchback allowance are measured in the x-y direction; etching the conformal coating from horizontal surfaces while retaining them on the sidewall to leave the hard mask sacrificial fins and conformal side coating spacers; and etching semiconductor substrate to form fins of a desired dimension; applying a second conformal coating layer to build a final thickness of the sacrificial fin and the coatings substantially equal to an additional etchback allowance of a semiconductor material; and etching the second conformal coating to leave hard mask and first conformal side coating spacers in unmasked areas.