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Low Distortion And Defect-Free Transfer of Prefabricated Circuits to Green Sheets

IP.com Disclosure Number: IPCOM000037746D
Original Publication Date: 1989-Jun-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Acocella, J: AUTHOR [+7]

Abstract

A method has been proposed which will avoid delamination or distortion when transferring prefabricated circuits to green sheets for use in multilayer ceramic (MLC) modules in semiconductor devices. Use of a UV sensitive adhesive provides a means of selectively controlling adhesion of the decal release layer.

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Low Distortion And Defect-Free Transfer of Prefabricated Circuits to Green Sheets

A method has been proposed which will avoid delamination or distortion when transferring prefabricated circuits to green sheets for use in multilayer ceramic (MLC) modules in semiconductor devices. Use of a UV sensitive adhesive provides a means of selectively controlling adhesion of the decal release layer.

Conventionally, circuits have been defined in MLC modules by screen printing of a metal paste through a metal mask onto a green sheet. The limited resolution prevents the definition of lines finer than 4 mil. The decal process has been used to define fine lines. In this method a metal circuit pattern is defined on a flexible carrier sheet such as polyester film. The circuit pattern is laminated to the green sheets by hot pressing and then the carrier sheet is removed by peeling. The adhesive layer normally remains with the pattern on the laminate and is burned off.

Polymethylmethacrylate (PMMA) has been used as the adhesive and while it has excellent adhesive and thermal decomposition properties, when the polyester film is released, distortions of the metal circuits may occur.

The proposal suggests use of a photosensitive adhesive, such as an acrylate-based dry film resist, so that the adhesion between the adhesive layer and the carrier sheet may be controlled by UV irradiation. In the process Cu foil is laminated between two layers of the film resist and the polyester film. The...