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:
Sep. 04, 2001
Filed:
Jun. 16, 1999
Angelo Pinto, Agusta, IT;
Sergio Palara, Aci Sant′ Antonio, IT;
STMicroelectronics S.r.l., Agrate Brianza, IT;
Abstract
The method comprises forming an implantation screening layer of predetermined thickness on the wafer, forming, in the screening layer, a first rectilinear, elongate opening having a first width, and at least a second rectilinear, elongate opening substantially parallel to the first opening and having a second width smaller than the first width is formed on the screening layer. The wafer is then subjected to ion implantation with two ion beams directed in directions substantially perpendicular to the longitudinal axes of the openings and inclined to the surface of the wafer at predetermined angles so as to strike the openings from two opposite sides. The thickness of the screening layer, the widths of the openings, and the angles of inclination of the ion beams being selected in a manner such that the beams strike the base of the first opening for substantially uniform doping of the underlying area of the wafer, but do not strike the base of the second opening. The novel method and apparatus enables selective doping by ion implantation to be performed without the use of a mask which is otherwise necessary for screening the second opening.