Browse Prior Art Database

Module Terminal Pin and Land Structure

IP.com Disclosure Number: IPCOM000093908D
Original Publication Date: 1966-Apr-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Antenucci, JA: AUTHOR

Abstract

This terminal pin and annular tapered land structure combination prevents cracking of the land when the pin is flexed. When module substrates are provided with printed circuitry on both sides, it is convenient to make a terminal pin and land connection on the bottom side. Normally the land is annular in shape and encircles the terminal pin and is adhered to the flat surface of the module. This structure is prone to land cracking.

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Module Terminal Pin and Land Structure

This terminal pin and annular tapered land structure combination prevents cracking of the land when the pin is flexed. When module substrates are provided with printed circuitry on both sides, it is convenient to make a terminal pin and land connection on the bottom side. Normally the land is annular in shape and encircles the terminal pin and is adhered to the flat surface of the module. This structure is prone to land cracking.

When the terminal pin is inserted and removed from a socket during assembly and disassembly of the module from a supporting structure, the pin is flexed. Such flexure stresses the land and can loosen the bond between the substrate surface and land adjacent the pin. Continued stressing causes the annular solder land around the terminal pin to heave. The bulk of the stress during flexure is then concentrated in the land adjacent the annular portion which has a smaller cross-sectional area. Additional flexing can result in land cracking and an open circuit.

This result can be avoided by providing an annular tapered land portion 10 joined to pin 12 on the bottom side 14 of substrate 16. Land 10 can be produced by countersinking aperture 18 receiving pin 12. Land 10 can then be formed by conventional techniques. Land 10 provides more surface contact area for bonding between both it and pin 12, and also land 10 and substrate 16. Land 10 becomes essentially an integral part of substrate 16.

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