Browse Prior Art Database

Solder Tinning Fixture

IP.com Disclosure Number: IPCOM000080942D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Larnerd, JD: AUTHOR [+2]

Abstract

In present day electronic technology there is a greater trend to the use of pluggable modules having gold on the leads, to enhance the electrical characteristics of the interconnections. In module assembly and to utilize the same tinning processes, which totally immerses the ceramic substrates into a solder pot, a method of selectively tinning only one surface of the substrate is needed.

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Solder Tinning Fixture

In present day electronic technology there is a greater trend to the use of pluggable modules having gold on the leads, to enhance the electrical characteristics of the interconnections. In module assembly and to utilize the same tinning processes, which totally immerses the ceramic substrates into a solder pot, a method of selectively tinning only one surface of the substrate is needed.

This is a tinning fixture which comprises a cover type structure 10, preferably of stainless steel, and providing nonwettable surfaces to solder. The cover 10 is designed to overlie one surface of the ceramic substrate 11 having gold-plated connector pins 12. A bracket 13 including the lead springs 13a which contact the edges of the substrate 11, function to hold the cover 10 in contact with the substrate 11 surface. No special seal is required between the ceramic substrate 11 and the contacting edge of the cover 10.

The natural surface tension of the solder against the nonwettable surface of the cover 10 and the ceramic substrate 11, prevents the solder from flowing into the clearance cavity of the cover and contaminating the gold-plated leads 12. Further, the air in the clearance cavity of the cover 10 expands as the assembly enters the molten solder, and the positive pressure created functions to prevent solder from flowing Into the cavity. This fixture can be used in the standard tinning processes with no attendant change to process parameters or toolin...