Browse Prior Art Database

Method of Attaching Pins and Substrates

IP.com Disclosure Number: IPCOM000052698D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Phelps, DW: AUTHOR [+3]

Abstract

One of the difficulties encountered in obtaining an effective, reliable pin structure on a substrate of a module is that of forming an effective, reliable connection between the pins and the vias on the substrate. Brazing and soldering have been the most utilized techniques, but these are more prone to failure, due to insufficient bond strength, than pins attached by welding. However, welding has not proved effective in attaching pins to vias due to cracking of the substrate due to thermal stresses. This article describes an improved module pin structure and technique for forming such structure.

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Method of Attaching Pins and Substrates

One of the difficulties encountered in obtaining an effective, reliable pin structure on a substrate of a module is that of forming an effective, reliable connection between the pins and the vias on the substrate. Brazing and soldering have been the most utilized techniques, but these are more prone to failure, due to insufficient bond strength, than pins attached by welding. However, welding has not proved effective in attaching pins to vias due to cracking of the substrate due to thermal stresses. This article describes an improved module pin structure and technique for forming such structure.

In the drawing, a substrate, which can be a single-layer substrate or a multilayer substrate formed of layers of ceramic, or layers of ceramic and plastic such as polyimide, is designated by the reference character 10. The substrate has metal-filled vias 12 extending from one side 14 of the structure to the opposite side 16. The side 14 is configured to have one or more silicon chips mounted thereon, and the side 16 receives the I/O pins 20.

As can be seen in the figure, the vias have a rather narrow section 22 extending from the side 14, and a thicker section 24 extending from the side 16. The thicker section 24 is substantially greater in diameter than the pin 20 to which it will be attached. The thin section 22 is preferably formed of tungsten or molybdenum, and the thicker section 24 is formed of a good braze or weldable materia...