Fillers are essential in the encapsulation molding compound. For three fillers of crystal, spherical, and fused silica, the effects of their size, type, and shape on the viscosity, flow spiral length, thermal conductivity, and coefficient of thermal expansion (CTE) of the compound were explored in this study. The results show that fillers with a larger particle size have a smaller viscosity and flow better; spherical fillers are better than the polygonal ones in this respect. In contrast, both thermal conductivity and CTE increase as the filler particle size increases; the values of these two properties of crystal silica are about twice those of fused silica; the thermal conductivity of polygonal silica is larger than that of spherical silica. On the other hand, the dependence of CTE on the filler shape is insignificant, but is significant to the filler type. The degree of curing of the compound with polygonal silica is also higher than that with either spherical or crystal silica. Namely, curing is affected by both filler type and shape, and can be tuned accordingly to suit specific needs.

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Encapsulation molding compounds (EMCs) are commonly used to protect integrated circuit (IC) chips. Their composition always contains fillers of a large amount (about 70%) and will affect the properties of the compounds. Thus, in order to clarify the filler effects, in this study, three types of silica fillers including crystal silica, edgeless silica, and fused silica were studied experimentally to explore their effects on the compounds. The results show that all of the flow spiral length, glass transition temperature (Tg), coefficient of thermal expansion (CTE), and water absorption rate of the encapsulation molding compounds decrease as the filler amount increases, irrespective of the filler type. In contrast, both thermal conductivity and flexural strength of the compounds increase as the filler amount increases, but also irrespective of the filler type. For the three fillers, the edgeless silica filler has the advantage of a large flow spiral length and can be molded better. It also has a larger thermal conductivity, larger flexural strength, and lower water absorption rate. Hence, for low stress industrial applications, the edgeless silica should be adopted as the filler of the encapsulation molding compounds.

During the preparation of thermosetting encapsulation molding compounds (EMCs) for semiconductor packaging, metal debris are always present in the EMC powders due to the hard silica fillers in the compound. These metal debris in the EMC powders will cause circuit shortage and therefore have to be removed before molding. In this study, Nd-Fe-B permanent magnets are used to remove these debris. The results show that the metal debris can be removed effectively as the rate of accumulation of the metal debris increases as time proceeds in the removing operation. The removal effectiveness of the debris is affected by both the magnetic flux density and the flow around the magnet. The wake flow behind the magnet is a relatively low speed recirculation region which facilities the attraction of metal debris in the powders. Thus, the largest amount of the accumulated EMC powders occurs downstream of the magnet. Hence, this low speed recirculation region should be better utilized to enhance the removal efficiency of the metal debris.

a b s t r a c tThis study evaluated the performance of combining two-stage H 2 O 2 /UV pre-oxidation with RO post-separation for the reuse of municipal wastewater. The results demonstrated that the two-stage H 2 O 2 /UV (H 2 O 2 = 0-30 mg/L) process was more effective than the one-stage (H 2 O 2 = 0-60 mg/L) process for mitigating RO membrane organic-fouling and bio-fouling. In thetwo-stage operation, the inactivated log reduction of microorganisms reached 4.96-logs, and the total organic carbon (TOC) was reduced from 18.0 to 2.98 mg/L. The silt density index (SDI) decreased from 9.8 to 3.9; the normalized flux decline (r) of RO separation was enhanced from 36% to 91%.