US 12,451,353 B2
Double hardmasks for self-aligned multi-patterning processes
Eric Chih-Fang Liu, Albany, NY (US); Christopher Cole, Albany, NY (US); Steven Grzeskowiak, Albany, NY (US); Katie Lutker-Lee, Albany, NY (US); Xinghua Sun, Albany, NY (US); and Daniel Santos Rivera, Albany, NY (US)
Assigned to Tokyo Electron Limited, Tokyo (JP)
Filed by Tokyo Electron Limited, Tokyo (JP)
Filed on Aug. 3, 2022, as Appl. No. 17/879,873.
Prior Publication US 2024/0047210 A1, Feb. 8, 2024
Int. Cl. H01L 21/033 (2006.01); H01L 21/02 (2006.01); H01L 21/308 (2006.01); H01L 21/311 (2006.01); H01L 21/3213 (2006.01)
CPC H01L 21/0332 (2013.01) [H01L 21/02164 (2013.01); H01L 21/0217 (2013.01); H01L 21/0337 (2013.01); H01L 21/0338 (2013.01); H01L 21/3081 (2013.01); H01L 21/3086 (2013.01); H01L 21/3088 (2013.01); H01L 21/31144 (2013.01); H01L 21/32139 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of processing a substrate, the method comprising:
forming recesses in a first mask layer over a mask stack comprising a lower hardmask, a middle mask, and an upper hardmask, the recesses defining an initial pattern comprising a plurality of spacer structures, each of the spacer structures having a first sidewall and an opposite second sidewall, the first sidewall having a different height from the opposite second sidewall, the lower hardmask and the upper hardmask comprising a metal-based mask material, and the middle mask comprising a silicon-based material;
etching the upper hardmask, selectively to the middle mask, to transfer the initial pattern to the upper hardmask;
etching the middle mask, selectively to the lower hardmask and the patterned upper hardmask, to transfer a pattern of the patterned upper hardmask to the middle mask; and
etching the lower hardmask, selectively to the patterned middle mask, to transfer a pattern of the patterned middle mask to the lower hardmask, wherein etching the lower hardmask consumes all of the patterned upper hardmask.