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Sealing of Apertures in Printed Circuit Packages

IP.com Disclosure Number: IPCOM000076170D
Original Publication Date: 1972-Jan-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Gardner, MJ: AUTHOR [+4]

Abstract

Where a requirement exists to selectively seal drilled apertures (e.g. drilled through holes) in a multiapertured printed circuit package, the following technique may be used to advantage:.

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Sealing of Apertures in Printed Circuit Packages

Where a requirement exists to selectively seal drilled apertures (e.g. drilled through holes) in a multiapertured printed circuit package, the following technique may be used to advantage:.

A plastic release film may be placed between the undrilled package "stock" and drill "back-up" material while drilling the stock. The film is thereby drilled in the "image" of a hole pattern made in the circuit stock. After drilling, the circuit stock and plastic may be separated and the stock processed further (e.g. for plating of the drilled holes, drilling of other holes, etc.).

At an appropriate stage of package processing, the plastic film may be realigned with the processed package and used as a contact mask for insertion of sealing material into the corresponding holes of the package. Sealing may be accomplished, either by silk screening a paste-type resin through the mask or by extruding B-stage epoxy film through the mask with heat and laminating pressure.

If the laminating/extrusion technique is used and the package contains additional holes or voids, which are covered over by the plastic mask and not intended to be filled, it will be necessary to control the lamination process to avoid rupturing of the mask at such unsupported positions (e.g. by limiting extrusion pressure or by prefilling the additional voids with removable heat resistant material).

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