Characterization and Analysis of Moisture absorption in Embedded System in Packaging

The embedded packaging technology which puts chip into cavity in substrate has the advantages of low cost, good heat dissipation, low parasitic inductance and popularizes in power devices, automotive electronics risely. However, materials used in embedded packaging such as Ajinomoto Build-up Film (ABF), bismalimides-triazine (BT), Polyimide (PI) could absorb moisture causing decrease in adhesion, and corrosion when devices are exposed to wet atmosphere lastingly. Studies has revealed that moisture is the third main factors which could make devices invalid or damaged, and it covers a rate of 19 % in all microelectronics failure factors. Three different materials -- A (ABF), B (BT), C (PI) were selected to measure their hygroscopic parameters, such as diffusivity (D), saturated moisture concentration (Csat), and coefficient of hygroscopic swelling (beta). The relationship between parameters, temperature and relative humidity (RH) was discussed. The test results indicated that sample C has the largest Csat as 29.43 kg/m(3), far exceeding B which is the lowest at 9.7 kg/m(3) under the 30 degrees C - 85% RH.