Moisture Effect on Physical Failure of Plastic Molded SiP Module

In the study, SiP module with IC chip and various size passive components (inductor and capacitor) is subjected to molding assembly process using 4 types of molding compounds with the same resin system but different filler size and filler contents which is resulting in different moisture uptake as well as their CTE, mold shrinkage and flexural modulus. The SiP module is subjected to MSL1, MSL2 and MSL3 precondition followed by 3 times 260°C reflow respectively. Afterwards, non-destructive failure analysis using SAT (Scanning Acoustic Tomography) to detect the delamination or popcorn occurrence and destructive Cross Section analysis plus SEM observation for actual failure mode identification are adopted. The typical failure modes in the SiP module are discussed to understand its moisture resisting ability. Moreover, moisture absorption and desorption curve at MSL1 85°C /85%RH is conducted to compare actual moisture behavior among the SiP module with the 4 types of molding compounds. Lastly, thermal warpage behavior using shadow morie method after MSL3 condition is also conducted to investigate moisture effect on the SiP module warpage behavior across reflow profile temperatures for a range of practical packaging applications. Consequently, SiP module related to MSL rating quality is concluded for the component optimum baking condition prior to the surface mounting process.