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:
Jan. 28, 1986
Filed:
Mar. 16, 1984
Edward C Fredericks, Haymarket, VA (US);
Herbert L Greenhaus, Reston, VA (US);
Madan M Nanda, Reston, VA (US);
Giorgio G Via, McLean, VA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A photoresist photolithographic process is disclosed which provides for a single development step to develop a dual layer photoresist for lift-off, reactive ion etching, or ion implantation processes requiring a precise aperture size at the top of the photoresist layer. The process involves the deposition of two compositionally similar layers, with the first layer having the characteristic of being soluble in a developer after exposure to light and baking, and the second layer having the characteristic of being insoluble in the same developer after having been exposed to light and baked. With these two distinct characteristics for the two layers of photoresist, the effective aperture for windows in the composite photoresist can be tightly controlled in its cross-sectional dimension in the face of large variations in the developer concentration and development time.