Pressureless Silver Sintering in Power Application

Abstract

The paper describes results of investigations concerning the behaviour of low-temperature silver die attach paste that does not require pressure while curing. Paste is an environmentally friendly product created as a substitute to lead solder, applied in power and high power application. This material has been developed for replacing eutectic solders offering the same thermal performance as AuSn solder. Experimental samples were prepared on standard substrates. Except various curing conditions we analyse quality of joints if various surface quality were used. We compared Au, Ag or AgPt thick films applied on ceramic (Al2O3 or LTCC). First measurements show that joint properties (microstructural analyse, mechanical properties, resistivity of joint, changing the resistance after a constant current loading) are the best on Au thick film applied on LTCC ceramic. Some problems on interface Ag thick film and Ag sintered paste surprised us. Paper describes results of reliability tests as well as.