US 11,892,777 B2
Systems and methods for contact immersion lithography
Hongqin Shi, San Jose, CA (US); Yeh-Jiun Tung, Sunnyvale, CA (US); James Dunphy, San Jose, CA (US); and Cesar Gensoli, Belmont, CA (US)
Assigned to Waymo LLC, Mountain View, CA (US)
Filed by Waymo LLC, Mountain View, CA (US)
Filed on Oct. 13, 2022, as Appl. No. 18/046,403.
Application 17/166,743 is a division of application No. 16/724,925, filed on Dec. 23, 2019, granted, now 10,948,830.
Application 18/046,403 is a continuation of application No. 17/166,743, filed on Feb. 3, 2021, granted, now 11,500,295.
Prior Publication US 2023/0055675 A1, Feb. 23, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. G03F 7/20 (2006.01); G03F 7/00 (2006.01)
CPC G03F 7/70341 (2013.01) [G03F 7/70925 (2013.01)] 17 Claims
OG exemplary drawing
 
1. An exposure unit comprising:
a photomask;
at least one wiper device, wherein the at least one wiper is configured to clean at least one surface of the photomask;
a particle- or bubble-detection device;
a fluid feeding and cleaning unit configured to provide a fluid, wherein the fluid feeding and cleaning unit comprises one or more filters, wherein the one or more filters comprise: a 0.2 micron filter, a 0.1 micron filter, and a 0.04 micron filter; and
a controller having at least one processor and a memory, wherein the at least one processor executes program instructions stored in the memory so as to carry out operations, the operations comprising:
receiving, from the particle- or bubble-detection device, information indicative of particles or bubbles present on the photomask; and
in response to receiving the information indicative of particles or bubbles present on the photomask, controlling the at least one wiper device to clean at least one surface of the photomask.