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Synthesis and properties of a low hygrothermal stress epoxy molding compound for electronic encapsulation
Author(s) -
Tai HorngJer,
Wang J. B.,
Chou HuiLung
Publication year - 2000
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.10248
Subject(s) - materials science , epoxy , composite material , molding (decorative) , siloxane , thermal expansion , shrinkage , glass transition , polymer
A vinyl siloxane‐modified cresol novolac epoxy (CNE)/cresol novolac hardener (CNH) molding compound with both siloxane and epoxy components capable of further crosslinking is synthesized. Through careful adjustment of TPP dosage, the Tg of CNE/CNH resins can be effectively controlled. The VS‐modified CNE/CNH compound possesses a lower Young's modulus, a lower linear coefficient of thermal expansion (LCTE), and a higher break strain than those of its unmodified counterpart. The combination of lower mechanical moduli and lower LCTE results in a 33% reduction in thermal stress caused by thermal mismatch. In addition to thermal mismatch, chemical shrinkage in a molding process is also an important factor that affects the interfacial strain between a compound and a substrate. The incorporation of vinyl siloxane (VS) incurs a 25% reduction in the equilibrium moisture uptake and a 16% reduction in the coefficient of diffusion for the VS‐modified compound. This modified compound can help alleviate the popcorning problems in IC packages resulting from hygrothermal stresses.