On the Use of Nanoscale Materials to Toughen Model Epoxies

摘要

A typical underfill resin consists of an epoxy matrix filled with micron-size silica particles to reduce thermalrnexpansion. The fracture toughness of such resins plays an important role in the reliability of flip-chip packages.rnIn this work, we will investigate the use of nanoscale materials to improve the fracture toughness of a modelrnepoxy resin. A lightly crosslinked model epoxy system was chosen due to its “toughenability.” The tougheningrnmechanisms are elucidated using a combination of electron and optical microscopy techniques. For epoxiesrntoughened with soft, nanosize rubber particles, the toughening mechanism is rubber particle cavitation andrnmatrix shear banding. The toughening mechanism when hard, nanosize silica particles are used involvesrnparticle matrix debonding and matrix shear banding.