Granted Patent
Utility
US 5,578,421 · App. 08/418,402
Photomask and pattern forming method employing the same
Inventors:
Norio Hasegawa, Fumio Murai, Katsuya Hayano
Patented Case
View Patent ↗
Granted: Nov 26, 1996
Filed: Apr 7, 1995
Inventors
Norio Hasegawa
Fumio Murai
Katsuya Hayano
Assignee (at issue)
HITACHI, LTD.
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.