Browse Prior Art Database

Defective Hole Repair/Hermetic Seal

IP.com Disclosure Number: IPCOM000051537D
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 52K

Publishing Venue

IBM

Related People

Sarnacki, FH: AUTHOR

Abstract

A permanently installed epoxy coated hollow member 10 is used to repair and hermetically seal a defective plated through hole (PTH) in a laminated multilayer printed circuit board (PCB).

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Defective Hole Repair/Hermetic Seal

A permanently installed epoxy coated hollow member 10 is used to repair and hermetically seal a defective plated through hole (PTH) in a laminated multilayer printed circuit board (PCB).

In the figure, PTH of original diameter D1, shown in outline form, is found to be defective. For example, it is assumed an undesired short circuit between a conductor C1 of the metallization plate P1 of the PCB and the PTH is present. To remove the defect, the plating of the PTH is drilled out using a drill with a larger predetermined diameter D2. Tubular member 10 has an appropriate compatible outer diameter. It consists of an inner elongated (initially straight) piece of solderable tubing 11, e.g., Cu, of a predetermined length which is concentrically coated with an outer layer 12 of partially cured, i.e., B cure stage, epoxy. For the particular defect example, i.e., the undesired short, the epoxy is a nonconductive, i.e., insulator, type. Member 10 is inserted into the newly drilled hole of diameter D2, and its ends extend outwardly from the two major, i.e., outer, surfaces of the PCB. Each end of member 10 is subjected to a flange- forming operation with an appropriate tool, e.g., a punch. As a result, the radial flanges 13 and 14 are formed, and the epoxy layer 12 is compressed between the external surfaces of member 10, i.e., under surfaces of flanges 13 and 14 and outer longitudinal side wall of member 10 located in the hole, and the adjacent surfaces of the PCB, i.e., the areas of the major surfaces of the PCB lying under the flanges, and the longitudinal surface of the side wall of the hole formed in the PCB.

Thereafter, a stem-like bifurcated resilient connector C is inserted into the opening of the tubing 11 and...