US 12,406,937 B2
Alignment method for backside photolithography process
Xinqi Ding, Guangdong (CN); Jiarui Ai, Guangdong (CN); Wang Jiao, Guangdong (CN); and Chao-chen Cheng, Guangdong (CN)
Assigned to SHENZHEN RUBEUST TECHNOLOGY LIMITED, Guangdong (CN)
Appl. No. 17/640,814
Filed by SHENZHEN RUBEUST TECHNOLOGY LIMITED, Guangdong (CN)
PCT Filed Nov. 20, 2020, PCT No. PCT/CN2020/130610
§ 371(c)(1), (2) Date Mar. 5, 2022,
PCT Pub. No. WO2021/098849, PCT Pub. Date May 27, 2021.
Claims priority of application No. 201911154536.8 (CN), filed on Nov. 22, 2019.
Prior Publication US 2022/0336368 A1, Oct. 20, 2022
Int. Cl. H01L 23/544 (2006.01); G03F 9/00 (2006.01); H01L 21/304 (2006.01)
CPC H01L 23/544 (2013.01) [G03F 9/7046 (2013.01); G03F 9/708 (2013.01); H01L 21/304 (2013.01); H01L 2223/54426 (2013.01)] 9 Claims
OG exemplary drawing
 
1. An alignment method for a wafer backside photolithography process, comprising:
cutting a wafer to form at least two edges serving as first alignment marks;
bonding a front side of the wafer with a pad, to form a composite wafer; and
aligning the first alignment marks on the composite wafer with second alignment marks on a photomask corresponding to the first alignment marks, respectively, to perform backside photolithography,
wherein said cutting the wafer to form at least two edges serving as the first alignment marks comprises:
providing a wafer; and
setting at least two preset cutting lines on a surface of the wafer on which a pattern is etched;
said setting at least two preset cutting lines on a surface of the wafer on which a pattern is etched comprises:
acquiring a plurality of distance reference values, wherein each of the plurality of distance reference values is one vertical distance of vertical distances from one first preset position of first preset positions of a pattern on the photomask to one second alignment mark of the second alignment marks; and
determining a plurality of cutting points on the wafer based on the plurality of distance reference values, the vertical distances, and second preset positions taken as starting points of the vertical distances; and then connecting the plurality of cutting points to form the at least two preset cutting lines; wherein the second preset position is a position of the pattern on the wafer corresponding to the first preset position.