Granted Patent
Utility
US 6,551,750 · App. 09/810,823
Self-aligned fabrication technique for tri-tone attenuated phase-shifting masks
Inventor:
Christophe Pierrat
Patented Case
View Patent ↗
Granted: Apr 22, 2003
Filed: Mar 16, 2001
Inventor
Christophe Pierrat
Assignee (at issue)
Numerical Technologies, Inc.
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.