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.