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:
Dec. 18, 1990
Filed:
Jan. 03, 1990
Valerie A Bach, Philomath, OR (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
Tapered via holes (10) of uniform diameter are formed in a dual-layer (SiO.sub.2 /SiNi) dielectric (18, 20) used for isolation of metallization layers in an integrated circuit. The method includes forming a photoresist layer (22) atop the nitride layer (20) and patterning the photoresist to define a via hole (24). The nitride and oxide layers are successively plasma etched through the photoresist-defined via holes (24) to form via holes (26, 28) through the dual-layer dielectric to an underlying metal line (16, 17). Etching of the nitride layer is selective to the oxide layer. Etching of the oxide layer is selective to the metal line. The photoresist and nitride layers are etched simultaneously in the presence of oxygen so as to taper the via hole in the nitride. The oxide is etched in the absence of oxygen, producing a tapered sidewall profile (32) extending continuously to the metal.