Influence of surface finish on resistance of contacts between ECA and Pad

Contact resistance between adhesive and pad is examined. Three types of adhesives based on bis-phenol resin matrix filled with silver flakes are studied on copper, nickel and gold surface finishes. The contact resistance is calculated as a difference between result of three terminal and four-terminal measurements. It is found that nickel surface finish is not proper for adhesive assembly, because the contact resistance between this surface finish and adhesive is too high, whereas the contact resistances for copper and gold finishes are comparable, markedly lower than the resistances of adhesive contacts on nickel and acceptable for this type of assembly.