Resistance characterization of Au bump and anisotropic conductive adhesives under temperature and moisture conditions

In this work, the effect of temperature and moisture on joint resistance of Au bump and ACA is reported. A flip chip on glass (FCOG) test vehicle was used to study the joint resistance of Au bump and ACA after temperature cycling (-40/spl deg/C/125/spl deg/C), temperature humidity testing (85/spl deg/C/85%RH) and moisture preconditioning (MSL 1/3/5). In general, the results showed that Au bump and ACP has a better performance than Au bump and ACF during temperature cycling, temperature humidity testing and moisture preconditioning. The size of the Au bump and conductive fillers is found to an important factor in achieving a joint with low and stable resistance. For improved temperature and moisture performance, the use of a larger Au bump size with a larger conductive filler size is recommended for ACAs.