Low-Stress Epoxy Encapsulants for Semiconductor Application

• Main Authors: Tzong-Hann Ho, 何宗漢
• Other Authors: Professor Chun-Shan Wang
• Format: Others
• Language: zh-TW
• Published: 1994
• Online Access: http://ndltd.ncl.edu.tw/handle/75295156547685810899

博士 === 國立成功大學 === 化學工程研究所 === 82 === Epoxy molding compounds (EMCs) have been widely used as encapsulation material for semiconductor devices. ο-Cresol- formaldehyde novolac epoxy (CNE) is the resin typically employed to encapsulate microelectronic devices. Upon cure, this multifunctional epoxy resin provides a densely cross- linked protective layer; however, it is relatively brittle. The scale of integration of LSIs is continuing upward, forcing the design of large chips and finer patterns that are more susceptible to internal stress failure. The prevailing surface mount technology (SMT) also generates thermal stress to devices. Internal stress causes packge cracking, passivation layer cracking, aluminum pattern deformation, etc. Therefore, the development of a low-stress EMC is required for high- reliability semiconductor devices. In this work, dispersed acrylate rubbers, vinyl-terminated polydimethylsiloxanes (VTPDMS), and hydride-terminated polydimethylsiloxanes (HTPDMS) were used to reduce the stress of CNE cured with phenolic novolac resin for electronic encapsulation. The effect of the alkyl group of the acrylate monomer on the phase separation of resulant elastomers from epoxy resin and the effects of structure, molecular weight, and contents of the vinylsiloxanes or the hydride-siloxanes on reducing the stress of encalpsulant were investigated. The thermomechanical and dynamic viscoelastic properties and morphologies of rubber-modified epoxy networks were also studied. Thermal stress was reduced by lowering of either the coefficient of thermal expansion (CTE) or the flexural modulus ....