Patent ID: 9564446
Date: 2017-02-07
CPC Classifications: H01L

Claim:
1. A process for forming a fin structure having a fin pitch of less than 40 nanometers, the process comprising: providing a multilayer structure overlaying a semiconductor substrate, wherein the multilayer structure comprises a planar cap layer, and alternating dielectric and hard mask layers stackedly arranged on the semiconductor substrate; lithographically patterning a photoresist disposed on the cap layer to form a first mandrel pattern consisting of first and second mandrel shapes; forming first sidewall spacers on the first mandrel pattern, wherein sidewall spacers between adjacent first and second mandrel shapes overlap or merge; removing the first mandrel pattern and etching the structure to form a second mandrel pattern consisting of a first mandrel shape and a second mandrel shape, wherein the second mandrel shape is at about two times a width of the first mandrel shape; forming second sidewall spacers on the second mandrel pattern; and etching the structure to form multiple fin pairs in the semiconductor substrate comprising fin pairs having a minimal spacing and fin pairs that are about two times the minimal spacing.