Effect of solder-ball pitch on the reliability of a thermally enhanced FC-PBGA assembly

• Main Authors: Ping-ChunShih, 施秉均
• Other Authors: Gien-Huang Wu
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/67031051779626474860

碩士 === 國立成功大學 === 機械工程學系 === 102 === In recent years, due to the IC assembly and packaging technology is developing to small size, fine pitch and high density. In this paper, the effect of solder-ball pitch on the reliability of the thermally enhanced FC-PBGA (Flip-Chip Plastic Ball Grid Array) assembly during Three thermal cycles with ranged -40oC to 125oC were investigated. As a result of the huge cost time and resource for thermal cyclic loading, the finite element analysis commercial software Ansys is used for simulation. then by using Ansys to simulate lead (63Sn37Pb) and lead-free (96.5Sn3.5Ag) solder balls under different pitch during three thermal cyclic loading. in this simulation, all the solder balls were modeled with nonlinear visco-plastic time and temperature dependent material properties based on Anand's model. Thus, the relative plastic strain range of the solder ball during thermal cyclic loading can be determined. according to the maximum stress and strain find out the critical solder ball. simultaneously, the critical solder ball occurs at the interface between PCB and Substrate. Solder ball reliability is predicted by the widely accepted Coffin-Manson equation. then by using Coffin-Manson equation to predict the fatigue life and reliability of the solder ball. the results show that the solder ball pitch decrease, fatigue life increase. and the reliability is comparing favorably lead with lead-free solder balls.