전자 디바이스의 기계적 신뢰성 향상을 위한 언더필 재료의 물성 인자에 관한 연구

초록

In this paper, two types of underfill with different additive contents were formulated to investigate the effects of the underfill properties on the mechanical reliability of electronic packages in portable electronic devices. Dynamic mechanical analyses (DMA), tensile tests and shear tests were conducted to examine the material properties of the underfill, such as the storage modulus (E′), glass transition temperature (Tg), mechanical strength, stiffness and modulus of toughness. In the DMA and tensile test results for cured underfill specimens, Underfill 1 without a flexible additive showed a low modulus of toughness, and Underfill 2 with a small amount of flexible additive exhibited a high modulus of toughness. For underfills with a similar Tg value, the underfill with the higher modulus of toughness exhibited better mechanical reliability than the underfills with high strength, stiffness and low modulus of toughness, due to their fracture resistance to crack propagation. Therefore, the modulus of toughness of the underfill should be predominantly considered, when developing or selecting an underfill to enhance the mechanical reliability of electronic devices, rather than excessively high mechanical strength or stiffness.

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