Toughness improvement study of epoxy molding compound

The effects of filler loading, types of rubber (elastomer) and glass transition temperature (Tg) on mold compound's toughness at room and high temperature (240°C) were investigated. The new simplified toughness test method based on ASTMD5049 was also developed. The study was done with L39 Taguchi method, 3 factors with 3 levels. The factors are filler percentage (88%,89% and 90%,) Tg value (defined as level 1, 1.5 and 2) and 3 types of rubber (A, B and C). In addition, the warpage of the materials using QFN package (4×4 and 7×7) was also characterized in this experiment. The results showed that at room temperature, the highest toughness was attained by the material with all 3 factors at the middle level. Whilst at high temperature of 240 °C, the highest toughness was attained by the sample with the highest filler loading, highest Tg value and C type of rubber. In terms of warpage, 90% filler loading material showed the lowest warpage on QFN, 4 × 4, and for QFN 7 × 7, 89% filler loading showed the best warpage performance. There was no significant effect on warpage with Tg range from 128 °C to 142 °C. Rubber A has proven to be the most significant factors contribute to warpage performance which showed the best warpage performance on both QFN 4 × 4 and 7 × 7.