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:
Mar. 10, 1987
Filed:
Oct. 30, 1985
Seiki Ogura, Hopewell Junction, NY (US);
Jacob Riseman, Poughkeepsie, NY (US);
Nivo Rovedo, Poughquag, NY (US);
Ronald N Schulz, Salt Point, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
In the process of sidewall image transfer, a vertical step is etched in some material and then a conformal layer of some other material is deposited over the step. By reactive ion etching the conformal material can be anisotropically etched which results in a sidewall spacer of the second material on the vertical surfaces of the step material. By removing the step material, the free standing spacer can then be used as a mask. One area in which improvement is desired is in the selectivity of the etch of the spacer to the material immediately below it. Because of the limited number of materials and reactive ion etching gases it is difficult to avoid an etch in the underlying layer as the sidewall spacer is formed. A suitable etch stop is employed beneath the step material to avoid the problem. Because of the usual technology, the spacer material is plasma deposited silicon nitride and the step material is photoresist. Polysilicon, aluminum or similar metal is employed as an etch stop, since it is not by a CF.sub.4 based gas which is used to form the spacer.