A Study of Fatigue and Failure Behavior of Conductive Adhesive Joints Subjected to Elevated Temperature and Humidity

Abstract

The use of conductive adhesives to replace solder joint connectors and other joining methods has enjoyed rapid growth in recent years. Major reasons for their use in electronic packaging are efficient load distribution over a larger area, comparable joint electrical conductivity, and environmental concerns for tin/lead solder. There are a number of issues that one needs to be concerned about in the design of joints bonded using conductive adhesives. One of these is the cyclic fatigue behavior of conductive adhesive interconnects under different environmental conditions, in which fatigue failure might occur due to either mechanical or thermal stresses varying in a cyclic manner. This paper addresses the effect of various environmental conditions, such as, elevated temperature, and humidity on the fatigue failure of conductive adhesive joints. For this purpose, conductive adhesive joints were prepared using stainless steel adherends, and tested using monotonic and cyclic mechanical loading in different environmental conditions. Furthermore, an in-depth analysis of the damage-path is also presented through a spectrum of experiments involving variable loading methodology.