ACF Nonlinear Material Properties in the Mechanical Analysis of Au Bump Bonding Process

• Main Authors: Ming-Sian Lyu, 呂明憲
• Other Authors: Chau-Fei Lee
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/87657520850924218060

碩士 === 國立成功大學 === 工程科學系碩博士班 === 93 === 　This paper divides ACF nonlinear material properties in the mechanical analysis of Au bump bonding process course into Three steps: (1)To press, in this step this mechanics analysis consider resin as fluid state can not bear pressure, all pressure is born by hyperelastic material of a two coefficients Mooney-Rivlin rubber conductive particle of inside ,(2)Add the resin and analyse in FEM. According to match step 1 force equilibrium state, set up the same structure stress distribution. (3)Cooling and unloading. Material parameters are offered in the references, the gold bump in all step above-mentioned is considered as multilinear isotropic material, Si chip, glass, polyimide, Al pad are considered as elastic material. It is linear viscoelastic model with Bulk, Shear relaxation modulus which builded by Generalize Maxwell Model and WLF time-temperature shift factors equation to consider the resin in second, third step, and conductive particle consider as elastic material. The analysis results shows that in the cooling process, different unloading speed doesn't effect the value and distribution of Y stress. After preserving for 30 seconds, its stress relaxation is also not apparent. 　For the stress on the bump and the conductive particle interface, compare the Poisson ratio function ν(t) which the value between 0.35 and 0.475 with the Poisson ratio constant 0.35, the latter will result lower Y stress and higher shear stress, It's more conservative for structure failure criterion. The Poisson ratio and CTE coupling has more effective to the average interface compression stress then the average interface shear stress. Bump width in the range of 85μm to 125 μm, height in range of 10μm to 18μm, doesn't effect the interface stress value and distribution very much.