US 12,248,252 B2
Bubble defect reduction
Akhil N. Singhal, Portland, OR (US); Bart Jan van Schravendijk, Palo Alto, CA (US); Girish A. Dixit, San Jose, CA (US); David C. Smith, Lake Oswego, OR (US); and Siva Krishnan Kanakasabapathy, Pleasanton, CA (US)
Assigned to Lam Research Corporation, Fremont, CA (US)
Appl. No. 17/293,000
Filed by Lam Research Corporation, Fremont, CA (US)
PCT Filed Nov. 15, 2019, PCT No. PCT/US2019/061891
§ 371(c)(1), (2) Date May 11, 2021,
PCT Pub. No. WO2020/102783, PCT Pub. Date May 22, 2020.
Claims priority of provisional application 62/768,641, filed on Nov. 16, 2018.
Prior Publication US 2022/0004103 A1, Jan. 6, 2022
Int. Cl. G03F 7/16 (2006.01); G03F 7/20 (2006.01); H01L 21/027 (2006.01)
CPC G03F 7/168 (2013.01) [G03F 7/2022 (2013.01); H01L 21/027 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A method of precuring a semiconductor substrate, the method comprising:
applying an un-patterned positive tone photoresist layer onto a surface of the semiconductor substrate;
precuring the semiconductor substrate by pre-exposing the photoresist layer uniformly to a plasma consisting of at least one of helium, argon, or nitrogen which generates before depositing a metal oxide layer onto the photoresist layer, wherein the photoresist layer remains un-patterned after the pre-exposing of the photoresist layer to the ultraviolet light;
creating patterned mandrels of the photoresist layer on the semiconductor substrate;
depositing a metal oxide layer onto the patterned mandrels, wherein the metal oxide layer comprises tin oxide, the tin oxide emitting electrons that soften the photoresist layer causing bubble defects, wherein the pre-exposing of the photoresist layer to the ultraviolet light reduces the softening of the photoresist layer caused by the electrons, thereby reducing the bubble defects; and
performing a spacer etch by etching the metal oxide layer to leave sidewall spacers of the metal oxide layer on the semiconductor substrate.