Browse Prior Art Database

Backfill System for PCB Rework

IP.com Disclosure Number: IPCOM000051935D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Reynolds, MJ: AUTHOR [+2]

Abstract

In this system, a fiber wick is inserted into and fills a hole that has been drilled in a multilayer printed circuit board (PCB) to remove a defect, e.g. a short-circuit. A low viscosity dielectric liquid, e.g., an epoxy-resin, is applied to and absorbed by the wick by capillary action and subsequently cured by an appropriate time/temperature cycle. Thereafter, the excess resin-impregnated wick on the outside of the hole is trimmed by milling or the like. The system prevents trapping of air in the hole and/or run-out of the resin during curing, as well as providing a compatible dimensionally stable backfill for the hole.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Backfill System for PCB Rework

In this system, a fiber wick is inserted into and fills a hole that has been drilled in a multilayer printed circuit board (PCB) to remove a defect, e.g. a short- circuit. A low viscosity dielectric liquid, e.g., an epoxy-resin, is applied to and absorbed by the wick by capillary action and subsequently cured by an appropriate time/temperature cycle. Thereafter, the excess resin-impregnated wick on the outside of the hole is trimmed by milling or the like. The system prevents trapping of air in the hole and/or run-out of the resin during curing, as well as providing a compatible dimensionally stable backfill for the hole.

Suitable materials for the wick are fiber glass or other synthetic fibers such as polyimide, nylon, polyester, etc. Amongst the natural fibers that can be used are cotton, paper, etc.

1