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:
Apr. 18, 1995
Filed:
Apr. 30, 1992
Ismail T Emesh, Cumberland, CA;
Northern Telecom Limited, Montreal, CA;
Abstract
A method is provided for low pressure chemical deposition of tungsten and tungsten metallization for defining interconnects for an integrated circuit. A surface layer of tungsten is provided which has a low film stress and a smooth surface characterized by a low diffuse reflectivity and high specular reflectivity, to facilitate photo-lithography. Tungsten is deposited by reduction of WF.sub.6 with H.sub.2 and SiH.sub.4 in nitrogen. Control of the gas flow rates, pressure, temperature and H.sub.2 /WF.sub.6 ratio in the reactive gas mixture provides for tailoring of the structure and characteristics of a deposited tungsten layer to provide high step coverage or a smooth surface for forming an overlying layer of tungsten which may be patterned photo-lithographically for defining interconnect. In order to provide metallization providing both good step coverage in via and contact holes and smooth surface for deposition of surface metallization, a two-stage tungsten deposition is provided.