Various Adhesives for Flip Chips

Abstract

Flip chips using various adhesives were studied. The assembly yields using nonconductive adhesive and anisotropic conductive film investigated were 97% and 100%, respectively. A packaging process using anisotropic conductive paste with a 100% packaging yield was developed. All the packages passed various reliability tests such as burn in, artificial sweat and humidity tests, and temperature cycling tests. The reliability of the packages was 100% meeting the requirements for an industrial application. A stud bump bonding process with reduced process steps was proposed. Curing of conductive adhesive and underfill epoxy was not required, resulting in reduced packaging time.