Patent ID: 11881401
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 9:
10. A method of forming metal features, comprising:
providing a substrate having a device thereon and an interlayer over the device;
forming an etching stop layer over the interlayer;
forming a mask layer over the etching stop layer, wherein the mask layer has opening patterns therein, and each of the opening patterns has a width and a length greater than the width and extending along a longitudinal direction thereof;
performing a directional etching process to the opening patterns, so as to increase the length of each of the opening patterns and simultaneously push two opposite sidewalls of each of the opening patterns away from each other, wherein the length of each of the opening patterns after the directional etching process is at least two times the length of each of the plurality of opening patterns before the directional etching process;
after the directional etching process, transferring the opening patterns to the etching stop layer; and
forming metal features in the opening patterns,
wherein the directional etching process comprises:
performing a depositing step to form a protection layer conformally on the mask layer, wherein the protection layer covers sidewalls and bottoms of the opening patterns;
performing an etching step to completely remove the protection layer and simultaneously increase the length of each of the opening patterns along the longitudinal direction thereof; and
repeating the deposition step and the etching step alternately multiple times.