Granted Patent
Utility
US 5,938,897 · App. 08/876,906
Method of manufacturing phase-shifting photomask blank
Inventors:
Akihiko Isao, Susumu Kawada, Yoshihiro Saito, Tsuneo Yamamoto, Atsushi Hayashi, Nobuyuki Yoshioka, Akira Chiba, Junji Miyazaki
Patented Case
View Patent ↗
Granted: Aug 17, 1999
Filed: Jun 16, 1997
Inventors
Akihiko Isao
Susumu Kawada
Yoshihiro Saito
Tsuneo Yamamoto
Atsushi Hayashi
Nobuyuki Yoshioka
Akira Chiba
Junji Miyazaki
Assignees (at issue)
Ulcoat (Ulvac Coating Corporation)
MITSUBISHI ELECTRIC CORPORATION
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.