US 12,134,824 B2
Undercut-free patterned aluminum nitride structure and methods for forming the same
Yuan-Chih Hsieh, Hsinchu (TW); Yi-Ren Wang, New Taipei (TW); and Hung-Hua Lin, Taipei (TW)
Assigned to Taiwan Semiconductor Manufacturing Company Limited, Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Company Limited, Hsinchu (TW)
Filed on Jun. 17, 2022, as Appl. No. 17/843,072.
Application 17/843,072 is a division of application No. 16/931,574, filed on Jul. 17, 2020, granted, now 11,371,133.
Prior Publication US 2022/0325396 A1, Oct. 13, 2022
Int. Cl. C23C 8/34 (2006.01); B81B 7/00 (2006.01); B81C 1/00 (2006.01); B81C 3/00 (2006.01)
CPC C23C 8/34 (2013.01) [B81B 7/0006 (2013.01); B81C 1/00095 (2013.01); B81C 1/00269 (2013.01); B81C 3/001 (2013.01); B81B 2207/094 (2013.01); B81C 2201/0154 (2013.01); B81C 2203/0118 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of patterning a microstructure, comprising:
forming at least one metal layer over a substrate;
forming an aluminum nitride layer on a top surface of the at least one metal layer;
converting a surface portion of the aluminum nitride layer into a continuous aluminum oxide-containing layer by oxidizing the surface portion;
forming a dielectric spacer layer over the continuous aluminum oxide-containing layer;
forming contact via cavities extending through the dielectric spacer layer, the continuous aluminum oxide-containing layer, and the aluminum nitride layer and down to a respective portion of the at least one metal layer using etch processes that contain a wet etch step that etches physically exposed portions of the aluminum nitride layer while suppressing formation of an undercut in the aluminum nitride layer; and
forming contact via structures in the contact via cavities.