US 12,261,045 B2
Patterning method
Victor M. Blanco, Leefdaal (BE); and Frederic Lazzarino, Hamme-Mille (BE)
Assigned to IMEC VZW, Leuven (BE)
Filed by IMEC VZW, Leuven (BE)
Filed on Jan. 3, 2022, as Appl. No. 17/567,361.
Claims priority of application No. 21151578 (EP), filed on Jan. 14, 2021.
Prior Publication US 2022/0223415 A1, Jul. 14, 2022
Int. Cl. H01L 21/033 (2006.01); H01L 21/311 (2006.01); H01L 21/3213 (2006.01)
CPC H01L 21/0337 (2013.01) [H01L 21/31144 (2013.01); H01L 21/32139 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A patterning method comprising:
over a lower pattern memorization layer for memorizing a pattern of first and second lower trenches, forming a pattern of first upper blocks, then an upper pattern memorization layer and then a pattern of second upper blocks;
thereafter patterning upper trenches in the upper pattern memorization layer using lithography and etching, and forming spacer lines along sidewalls of the upper trenches to define spacer-provided upper trenches, at least a subset being interrupted by a respective first upper block;
patterning the first lower trenches in the lower pattern memorization layer by etching the spacer-provided upper trenches into the lower pattern memorization layer, at least a subset of the first lower trenches being interrupted by a respective lower pattern memorization layer portion preserved at a location defined by a respective one of the first upper blocks;
thereafter, forming an auxiliary trench mask stack and patterning auxiliary trenches therein using lithography and etching; and
thereafter, patterning the second lower trenches in the lower pattern memorization layer, the patterning comprising using the patterned auxiliary trench mask stack, the spacer lines and the second upper blocks as etch masks, at least a subset of the second lower trenches being interrupted by a respective lower pattern memorization layer portion preserved at a position defined by a respective one of the second upper blocks.