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Browse Prior Art Database

Printed Wiring Board Manufacturing

IP.com Disclosure Number: IPCOM000098560D
Original Publication Date: 1959-Feb-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Huopana, RO: AUTHOR

Abstract

This printed wiring board manufacturing process provides a two-sided assembly having plated holes connecting certain terminals on one side of the board with terminals on the other side of the board. Component leads mounted in such holes are secured to them by dip-soldering the entire board. This process of manufacture prevents adherence of the solder to the printed wire conductors between terminals, thus eliminating the possibility of solder improperly flashing over between two closely spaced conductors.

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Printed Wiring Board Manufacturing

This printed wiring board manufacturing process provides a two-sided assembly having plated holes connecting certain terminals on one side of the board with terminals on the other side of the board. Component leads mounted in such holes are secured to them by dip-soldering the entire board. This process of manufacture prevents adherence of the solder to the printed wire conductors between terminals, thus eliminating the possibility of solder improperly flashing over between two closely spaced conductors.

In the process, the copper foil on each side of an insulated board is printed and etched in a conventional manner to leave only the desired conductor pattern in the form of terminal lands and interconnecting conductors. Holes are drilled at the terminal land centers.

The board surfaces and the walls of the holes are sensitized or coated with a thin layer of conductive material to provide a single electrode. The conductors between the terminal lands are coated with a resist. The terminal lands and hole walls are electro-plated with copper to build up a suitable thickness and then with gold, after which the resist is removed from the conductors between the terminal lands.

The board is next immersed in a suitable chemical solution which removes the thin conductive coating from the nonconductive areas of the board. This does not remove the conductors themselves, since they are much thicker.

The board is then immersed in a chemical s...