US 12,130,550 B2
Pellicle frame, pellicle, and method of producing pellicle frame
Yuichi Hamada, Takasaki (JP)
Assigned to Shin-Etsu Chemical Co., Ltd., Tokyo (JP)
Filed by Shin-Etsu Chemical Co., Ltd., Tokyo (JP)
Filed on Aug. 15, 2022, as Appl. No. 17/819,727.
Application 17/819,727 is a continuation of application No. 17/223,853, filed on Apr. 6, 2021, granted, now 11,474,427.
Application 17/223,853 is a continuation of application No. 16/371,478, filed on Apr. 1, 2019, granted, now 11,003,070, issued on May 11, 2021.
Claims priority of application No. 2018-071568 (JP), filed on Apr. 3, 2018.
Prior Publication US 2022/0390830 A1, Dec. 8, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. G03F 1/64 (2012.01)
CPC G03F 1/64 (2013.01) 20 Claims
OG exemplary drawing
 
1. A pellicle frame comprising a frame base having an anodized film on a surface thereof and covered with a transparent polymer film, wherein the pellicle frame has such a property that a sulfate ion is not detected upon an ion analysis of pure water as performed after immersing the pellicle frame in 100 mL of the pure water at 90° C. for 3 hours.