Mesomechanics analysis on fracture behavior of silica filled epoxy encapsulants

摘要

The silica particulate filled epoxide resins are used as encapsulatn materials in semiconductor packaging. In the present paper, mixed-mode fracture behavior of the epoxide resin containing 70wtpercent silica particles ahve been studied under room temperature and high temperature, i.e., 250 deg C The three- and four-point bending tests were performed to obtain mode I and mixed-mode fracture toughness, respectively. The specimen fractured in a brittle manner under room temperature and the results obeyed the maximum hoop stress criterion. On the other hand, the results under high temperature showed relatively low dependency on mode II stress intensity factor. Fracture surfaces were observed by scanning laser microscope. Finite element analysis has been conducted by taking account of the microstructure of the material to investigate of the influence of the temperature on mixed-mode fracture behaviors. Local fracture criterions were considered for silica particles and epoxide resin. The material constants in the criterions were estimated from the bending strength and mode I fracture toughness of the material. Good agreement between experimental and numerical results was obtained for the fracture boundary curves on the mode I and mode II stress intensity diagram.