Flip chip encapsulant
02/01/1999
Flip chip encapsulant
This "no flow-flux" underfill encapsulant reduces cycle time in flip chip assembly. The underfill eliminates the separate fluxing, cleaning, and underfilling steps because the adhesive itself performs the dual role of fluxing the interconnects, then curing to become the underfill layer. Also, the underfill can be cured during the solder reflow process; there is no need for a separate curing cycle. Commercial flip chip tests have shown the underfill`s durability: following three reflow cycles it has passed over 1200 temperature cycles from -65 to 150?C, and counting. Emerson & Cuming Specialty Polymers, Billerica, MA; ph 800/832-4929, e-mail damian.