PRESSURIZED UNDERFILL ENCAPSULATION OF INTEGRATED CIRCUITS
A new method and device to encapsulate integrated circuits such as flip chips and BGA packages. A special mold (31) to surround the chip (32) to be encapsulated in a cavity (43), and the encapsulant (41) is injected into the cavity at an elevated pressure, and possibly at an elevated temperature. This shortens the cavity filling time by two or three orders of magnitude, compared to the conventional dispensing process. The reliability of the package is increased by increasing the adhesion of encapsulant to the package, by controlling fillet shape (51) through in-mold curing, and by completely filling the cavity through proper mold design and, optionally, evacuation of the cavity prior to injection. The invention also allows the use of a wider range of encapsulants, including highly viscous material, fast curing materials and reworkable materials.