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Technique for Improving Adhesion and Throughput in the Manufacture of Large Printed Circuit Boards

IP.com Disclosure Number: IPCOM000037534D
Original Publication Date: 1989-Mar-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Samuelson, CE: AUTHOR

Abstract

The new technology large boards require electrically isolated module sites for separate power feeds using drilled copper foil. To obtain electrically isolated module sites, it is necessary to have an intermediate lamination step where the prepreg is used for mechanical strength on completion of the second isolation border.

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Technique for Improving Adhesion and Throughput in the Manufacture of Large Printed Circuit Boards

The new technology large boards require electrically isolated module sites for separate power feeds using drilled copper foil. To obtain electrically isolated module sites, it is necessary to have an intermediate lamination step where the prepreg is used for mechanical strength on completion of the second isolation border.

After the copper plane has been through the first isolation border process, a sheet of prepreg is laminated on one side, or both sides, of the copper plane. Present practice uses MR release material, available from Dupont, to prevent the prepreg from sticking to adjacent surfaces. Once the MR release material is removed, the bonded copper plane is brought to profile where the second isolation border is introduced, thus completing the electrical isolation.

In the past, the MR film has produced "spotty" adhesion problems, to a point where samples would not pass a twenty minute pressure cooker test. However, by following this present technique, complete adhesion is obtained.

This technique pertains to a partial cure of the prepreg at the intermediate lamination step allowing the resin to fully cure at subsequent composite lamination, as contrasted with the conventional method of laminating the prepreg on one or both sides, using the standard lamination cycle which included 80 minutes of heat at 350 degrees Fahrenheit.

The present technique involves r...