Enhanced Reliability of a RF-SiP with Mold Encapsulation and EMI Shielding

Abstract

The paper concludes the details on how molding encapsulation, with coated shielding layer, could have improved the reliability of a SiP (System in Package) module. The EMI shielding structure is by using conformal metal film over molding and is contacted with substrate ground inner layers at package side. The study included process integration details, reliability test data, as well as the RF performance of the SiP module with EMI package shielding; with integration of high density surface-mount technology (SMT), Cu wire bond, mold encapsulation, conformal shielding and bottom side pre-solder processes. It was shown by molding this type of package structure in combination with an EMI shielding structure, a reduced moisture absorption rate can be achieved when comparing a non-EMI shielding structure. Temperature humidity test, with 85°C/ 85%RH environment, was carried out to benchmark the effect of moisture sensitivity of a module. In addition, mechanical testes such as shock, vibration, and drop tests were carried out to compare the molding module as to a metal lid type module. Thermal performance differences between modules with and without EMI shielding was also investigated to understand performance capabilities at higher operating temp. The thermal simulation of the molded type SiP module with EMI shielding result was equivalent to thermal measurement result using a baseline at 85°C ambient temperature. Based on the study, it was found molded SiP module with EMI shielding showed an enhanced thermal rate that was 6.63% higher than the metal lid type module and 1.23% higher than the molded only encapsulated SiP package individually.