Browse Prior Art Database

Solder Mask Process

IP.com Disclosure Number: IPCOM000097788D
Original Publication Date: 1961-Jul-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Allen, LB: AUTHOR [+3]

Abstract

A solder mask material particularly adaptable to dip soldering is provided and is applied by a suitable process to Standard Modular System (SMS insulating wafer) cards in an assembly line. A typical solder mask formula is as follows:

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Solder Mask Process

A solder mask material particularly adaptable to dip soldering is provided and is applied by a suitable process to Standard Modular System (SMS insulating wafer) cards in an assembly line. A typical solder mask formula is as follows:

1. 100% solids epoxy or modified epoxy resin 100 parts 2. Colloidal silica
2.5 parts 3. Modified amine hardener 13 parts Selected ones of commercially available resins, flow control agents and modified amine hardeners are used.

During the manufacture of an SMS card 1, a printed circuitry pattern is produced on one surface of the card consisting of a plurality of lines 2 and lands
3. A suitably formulated epoxy material is applied to the card through a silk or steel mesh screen containing a desired pattern to provide a solder mask 4 covering over the lines and leaving uncoated the lands or other areas where it is desired to solder.

The screened material is then caused to flow out to a smooth surface by means of hot high velocity air impinging directly on the surface. The masking material is cured by oven drying for about five minutes. At some subsequent point on the assembly line, the card is passed through a dip soldering bath to adhere solder only to the land areas.

The cured solder mask material remains on the finished card and provides good dielectric coverage for the lines 2.

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