Silica-filled epoxy molding compounds

Fig. 31. Comparison of the profile of the apparent mean viscosity vs, time for the silica filled epoxy molding compound, measured by RPA. (O denotes conventional crushed fused silica and denotes spherical fused silica)...

Because of the thermal contraction mismatch of a silicon chip, metal lead-frame and silica-filled epoxy molding compound integrated circuit (IC) packages bow or warp when cooled to room temperature after manufacture. The magnitude of the bow in an IC package can be determined quantitatively by... 

Silica-filled epoxy molding compounds use an epoxysilane for such a reason. In some cases, special epoxysilanes that have low chloride and low ionic content are used to further minimize negative effects on electrical properties. 

The moisture resistance properties of filled molding compounds are enhanced by the treatment of the fillers with silane adhesion promoters prior to compounding. Silane promoters on wollastonite fillers in thermoplastic polyester molding compounds (50 percent filled) will improve the flexural strength after 16 h in 50°C water by as much as 40 percent. Silane-treated silica fillers have been found to significantly increase the moisture resistance of epoxy adhesives used in the electronics industry for chip, surface-mounted, and printed-circuit processes.8... 

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