The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 18, 2003
Filed:
Dec. 07, 2000
Applicant:
Inventors:
Matteo Patelmo, Bernareggio, IT;
Giovanna Dalla Libera, Monza, IT;
Nadia Galbiati, Seregno, IT;
Bruno Vajana, Bergamo, IT;
Assignee:
STMicroelectronics S.r.l., Agrate Brianza, IT;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L 2/976 ; H01L 2/994 ; H01L 3/1113 ;
U.S. Cl.
CPC ...
H01L 2/976 ; H01L 2/994 ; H01L 3/1113 ;
Abstract
The invention relates to a method of producing a multi-level memory of the ROM type in a CMOS process of the dual gate type. Specifically, some of the transistors of the ROM cells have their polysilicon layers masked and the ROM cells are then implanted by a first dopant species in the active areas of the exposed transistors. Then the masks are removed from the polysilicon layer, and a second dopant species is implanted in said previously covered layer.