Low Temperature Processing Conductive Adhesives for High Temperature Applications
Authors: Binghua Pan, Chee Keng Yeo, and Su Liang Chan Company: Delphi Automotive Systems Singapore Pte Ltd Date Published: 2/14/2012
Pan Pacific Symposium
Abstract: This paper reports evaluation of four different Transient Liquid Phase Sintering (TLPS) conductive adhesives with different types of solder fillers. Metallurgical joints formed by these adhesives eliminate the typical concerns on traditional flux residual and potential corrosion due to moisture. The paper mainly focuses on the type of adhesive with SnBi that can be processed using low temperature profiles, yet its formed assemblies can meet automotive high temperature applications due to the shift of its melting point to a much higher value. A thermal test die PST02 was used for die attach on Cu substrate using all four adhesives, plus a eutectic SnPb solder and a Ag-epoxy adhesive as controls for comparison. X-ray was used to check void formation and cross section followed by SEM were conducted to study the quality of the metallurgical network. Die shear force was used to verify the joint strength and quality. Thermal resistance measurement was used to verify thermal performance of joints. Reliability performance tests, including both thermal cycling (T/C, -40 ºC to +125 ºC) and high temperature storage (HTS, 150 ºC), were performed to assess all formed and processed joints in terms of metallurgical behavior, adhesion and thermal performance throughout 1,000 cycles / hours of testing.
Transient Liquid Phase Sintering (TLPS) conductive adhesive, low temperature processing, high temperature application, thermal resistance