Advanced encapsulant systems for flip chip

Flip chip on board (FCOB) technology is a novel electronic assembly structure whereby a bare integrated circuit (IC) die is interconnected directly to an organic printed circuit board (PCB). Mechanical coupling of the die and PCB by an epoxy encapsulant enhances the performance of the FCOB assembly during reliability testing. Advanced encapsulant materials for FCOB must address the issues observed during assembly of consumer electronic products on a high volume manufacturing line. The development of these materials is critical to continue the integration of FCOB assemblies as an alternative packaging system in electronic products. Materials characterization studies were performed to determine the glass transition temperatures (Tg), tensile elastic and loss moduli (E' and E"), flow profiles, coefficients of thermal expansion (CTE), and apparent strengths of adhesion for several advanced encapsulants. In addition, reliability tests were conducted to observe the relationship between encapsulant materials properties and reliability responses.