Browse Prior Art Database

Used Electronic Module Pin Solder Dress Process

IP.com Disclosure Number: IPCOM000046642D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Dumaine, G: AUTHOR [+2]

Abstract

Single-chip (or multi-chip) modules are commonly used in mass production especially for high performance computers, and the need for replacing one or more chips may arise in certain cases, for example, if found defective. In order to repair the module, it is desoldered from the printed card on which it was mounted, and then repaired. With VLSI chips, such a module may be very costly, so it is highly desirable to be able to remove all the solder remaining on the pins after the desoldering operation, to put it in such good condition that it may be used again. An alternative to the process of dressing of pins of used modules for further reworking, as described in the IBM Technical Disclosure Bulletin 24, 5170-5171, (March 1982) will be herein disclosed.

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Used Electronic Module Pin Solder Dress Process

Single-chip (or multi-chip) modules are commonly used in mass production especially for high performance computers, and the need for replacing one or more chips may arise in certain cases, for example, if found defective. In order to repair the module, it is desoldered from the printed card on which it was mounted, and then repaired. With VLSI chips, such a module may be very costly, so it is highly desirable to be able to remove all the solder remaining on the pins after the desoldering operation, to put it in such good condition that it may be used again. An alternative to the process of dressing of pins of used modules for further reworking, as described in the IBM Technical Disclosure Bulletin 24, 5170-5171, (March 1982) will be herein disclosed. 1) The stripping of the remaining Pb/Sn solder is effected by the immersion of the pins in a specific acid bath (20% HBF4, 3% propionic acid, remainder deionized (DI) water) during 2 minutes, followed by a rinse in DI water (15 minutes minimum). 2) The brushing of pins with Scrub Cleaner powder (manufactured by the Shipley Company, Inc.) during 3 minutes, followed by DI water rinsing (30 minutes minimum) in order to deoxidize the nickel, which basically constitutes the material of the pins. 3) A first electroless gold plating to obtain a .25 m gold thickness, followed by a DI water rinsing (15 minutes minimum) 4) A final electroless gold plating to obtain 2.5 m gold thi...