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Browse Prior Art Database

Photosensitive Epoxy Resist

IP.com Disclosure Number: IPCOM000093599D
Original Publication Date: 1967-Nov-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Abolafia, OR: AUTHOR

Abstract

An epoxy varnish catalyzed by a dicyandiamide-amine catelyst system is made photosensitive by the addition of a dichromate, for example, potassium dichromate. The sensitized epoxy varnish is used as an etch resist. The latter can be removed after an etching operation or it can be heated to form an insulating layer on a printed circuit board. The epoxy varnish is heated under reflux conditions to increase its molecular weight, care being taken not to cause cross-linking of the epoxy. Upon cooling of the varnish, it is dissolved in a solvent, e.g., dimethyl sulfoxide, having dissolved therein potassium dichromate. The resulting solution is coated on a substrate and exposed to actinic radiation under a predetermined pattern. The unexposed sensitized varnish is removed by a 2:1 methylene chloridemethyl ethyl ketone solution.

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Photosensitive Epoxy Resist

An epoxy varnish catalyzed by a dicyandiamide-amine catelyst system is made photosensitive by the addition of a dichromate, for example, potassium dichromate. The sensitized epoxy varnish is used as an etch resist. The latter can be removed after an etching operation or it can be heated to form an insulating layer on a printed circuit board. The epoxy varnish is heated under reflux conditions to increase its molecular weight, care being taken not to cause cross-linking of the epoxy. Upon cooling of the varnish, it is dissolved in a solvent, e.g., dimethyl sulfoxide, having dissolved therein potassium dichromate. The resulting solution is coated on a substrate and exposed to actinic radiation under a predetermined pattern. The unexposed sensitized varnish is removed by a 2:1 methylene chloridemethyl ethyl ketone solution. After an etching operation, the exposed varnish is easily removed by methylene chloride.

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