SMT-compatibility of adhesive flip chip on foil interconnections with 40-/spl mu/m pitch

The manufacturing and reliability of a novel type of first-level interconnections is described. Anisotropic conductive and nonconductive adhesives are used to electrically bond flip chip ICs with a pitch of 60 and 40 /spl mu/m to flexible substrates. Analyses cover the initial state of the samples as well as their performance in the JEDEC moisture sensitivity level assessment and subsequent life testing. From the different behavior of the two types of adhesives a failure mechanism issues for the reflow-soldering test.