Liquid encapsulant resin and VPES (Vacuum Printing Encapsulation Systems) process were developed for SIP included FC and passive component, etc. with solder joint. In the case of RF module, PKG size can be made thin and small in comparison with the metal cap of the conventional technology. However, such module should repeatedly reflow for mounting on the mother board. Otherwise, it will cause the problem of the solder bridge inside of PKG when it is encapsulated by resin. In consideration of this point, this resin not only dropped down the coefficient of thermal expansion and the elastic modulus simultaneously, but also improved the adhesiveness. As a result, it is able to pass the severe pre-condition. Moreover, it succeeded in molding and underfilling simultaneously by using single-species resin in VPES process. Since there is no interface between underfill material and over mold resin inside of PKG, reliability can be improved further. This paper describes the unique of over molding process by VPES, liquid resin and its reliability.
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