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Landless Hole Circuit Card

IP.com Disclosure Number: IPCOM000092856D
Original Publication Date: 1967-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Crimi, JS: AUTHOR [+2]

Abstract

The process is for selectively plating holes provided in circuit boards 2 composed of organic or other nonconductive insulating materials 3. Thus plate or metallic coating is integrally bonded to the hole wall surfaces. Electrical continuity is established between associated circuitry on opposite sides of board 2, and from the copper claddings 4 and 5 shown in A.

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Landless Hole Circuit Card

The process is for selectively plating holes provided in circuit boards 2 composed of organic or other nonconductive insulating materials 3. Thus plate or metallic coating is integrally bonded to the hole wall surfaces. Electrical continuity is established between associated circuitry on opposite sides of board 2, and from the copper claddings 4 and 5 shown in A.

As shown in B, a layer of solder-resist 6 is applied over the entire surfaces of claddings 4 and 5, such as through a patternless silk screen 7. Following application of solder-resist 6, the side walls of holes 1 are suitably plated, as by an electroless process, with an initial or base coating 8 of copper.

The next step of the process, as in drawing C, is to plate a tin-lead layer 9 or other appropriate layer, i. e., tin, over the copper-coated side walls of holes 1 in any conventional manner. This is followed by removal of solder-resist 6 from claddings 4 and 5. Photoresist 10 is then applied over both claddings 4 and 5, as in D, selectively exposed to provide a desired conductive pattern 11 after the undesired portions 12 of claddings 4 and 5 are etched away.

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