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Solventless Development of Polymeric Films

IP.com Disclosure Number: IPCOM000077136D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Cortellino, CA: AUTHOR [+3]

Abstract

Photoresist materials, after exposure to radiation, have been developed in dissolving solutions to bring out the image areas. The solvent development swells the resist in the case of a negative resist and adhesion is lost at the edges of the image. In the case of a positive resist, the image is widened and adhesion is also lost at the resist edge. Both positive and negative resist also lose thickness which is a possible cause of pinholes.

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Solventless Development of Polymeric Films

Photoresist materials, after exposure to radiation, have been developed in dissolving solutions to bring out the image areas. The solvent development swells the resist in the case of a negative resist and adhesion is lost at the edges of the image. In the case of a positive resist, the image is widened and adhesion is also lost at the resist edge. Both positive and negative resist also lose thickness which is a possible cause of pinholes.

In the case of polymethylmethacrylate electron beam resists, such as ELVACITE* 2010 and t-butyl methacrylate, more thickness is lost during development than normal positive resist. If a film is cast at 7000 Angstroms, up to 3500 Angstroms is lost by solvent development of these particular photoresists. In addition the images are widened by the solvent attack on the edges.

After development, the resist required a postbake to (1) remove solvent and
(2) improve adhesion. The developing process also attacked nonimage areas.

It has been found that heating the photoresist to bring out the image rather than developing the photoresist in solvent produces improved results. In this manner, the developing step is eliminated, adhesion is improved, and greater fidelity is obtained in the image areas. Heating of the resist can be performed in a variety of ways, such as by hot plate, by Infrared (IR) heat or by microwaves. Using IR or microwaves permits automation of the system. It is also possible to...