Patent ID: 9679809
Date: 2017-06-13
CPC Classifications: H01L

Claim:
1. A method comprising: providing a structure having a first lithographic stack, a mandrel layer and a pattern layer disposed over a dielectric stack; patterning the structure to form mandrels in the mandrel layer; disposing a spacer layer over the mandrels; etching the spacer layer to form spacers disposed on sidewalls of the mandrels, the spacers and mandrels defining beta and gamma regions extending normally through the dielectric stack; etching a beta pillar mask over a beta region, the beta pillar mask not extending over any adjacent beta regions, the beta pillar mask extending over and defining a beta block mask portion of the pattern layer disposed within the beta region; disposing a second lithographic stack of layers over the structure, the second lithographic stack including a resist layer as a top layer and a spin-on hardmask (SOH) layer as a bottom layer; patterning a gamma pillar mask into the resist layer, the gamma pillar mask being disposed over a gamma region, the gamma pillar mask not extending over any adjacent gamma regions, the gamma pillar mask extending over and defining a gamma block mask portion of the pattern layer disposed within the gamma region; anisotropically etching the lithographic stack through the SOH layer to form the gamma pillar mask into the SOH layer and to expose portions of the pattern layer in gamma regions not covered by the gamma pillar mask; etching the structure to form a pattern in the pattern layer, the pattern including the gamma and beta block mask portions formed from the gamma and beta pillar masks; and selectively etching the exposed portions of pattern layer to form gamma interconnect line locations of the pattern.