Browse Prior Art Database

Solder Joint Life Improvement Using Adhesive Under Component

IP.com Disclosure Number: IPCOM000102756D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 28K

Publishing Venue

IBM

Related People

Nagerl, AJ: AUTHOR

Abstract

Disclosed is a method of increasing the solder joint life of leadless chip carriers (LCC's) soldered to organic circuit boards. High shear stresses developed during temperature cycling due to a mismatch in the thermal coefficient of expansion between the LCC and circuit board limit the life of the solder joints.

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Solder Joint Life Improvement Using Adhesive Under Component

      Disclosed is a method of increasing the solder joint life of
leadless chip carriers (LCC's) soldered to organic circuit boards.
High shear stresses developed during temperature cycling due to a
mismatch in the thermal coefficient of expansion between the LCC and
circuit board limit the life of the solder joints.

      If the gap between the LCC and the circuit board is filled with
a suitable adhesive, the shear stress at the solder joints will be
reduced.  This is the result of the adhesive mechanically coupling
the lower modulus circuit board to the higher modulus LCC.

      For example, polyurethane adhesive 1 is used between ceramic
LCC 2 and epoxy/glass circuit board 3.  The life of solder joints 4
were measured to be two to three times greater than for the case with
no adhesive.

      Disclosed anonymously.