Investigations on the Thermo-Mechanical Characteristics of Solder Joint with a Polymer Reinforced Wafer Level Package

• Main Author: 翁嘉濬
• Other Authors: 蔡新春
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/21158872502604324330

碩士 === 明新科技大學 === 精密機電工程研究所 === 100 === In recent years, wafer level package is the most attention in the global IC packaging industry. It is more lightly, smaller, shorter, and more advantages than the multi-chip module, ball grid array and flip chip in the manufacturing processes and the material costs. There is a technique in the wafer level packaging process which is to strengthen solder joint with the polymer collar. Polymer collar is embedded around the solder joints of wafer level package and offer the ring protection layer of solder joints. It would strengthen effectively on the bonded strength of the solder joint in wafer level package. It is analyzed and discussed that how much degree of the height of polymer collar would influence the mechanical properties of solder joint in this paper. This paper utilize 3D-1/8 simplified symmetric model of wafer level package to investigate the thermo-mechanical behaviors of solder joint with the polymer collar. Both solders of lead alloy (62Sn-36Pb-2Ag) and lead-free alloy (95.5Sn-3.8Ag-0.7Cu) are examined under the temperature cycling of between -40 ℃ and 125 ℃ by using finite element software-ANSYS. The three polymer collar heights of 0 mm, 0.04455mm and 0.0891mm with four different ramp rates of 5.5℃/min, 6.6℃/min, 8.25℃/min and 11℃/min are provided to compare the thermo-mechanical characteristics of the solder joint with polymer collar under the dwelling time of 15 minutes, respectively. It would explore thermo-mechanical behaviors of the shear stress, the plastic-creep strain and the shear stress versus the plastic-creep strain hysteresis loops under the distortion and/or deformation of solder joint with the temperature cyclic loading. And it is discussed that the most impact of thermo-mechanical characteristics is on what the state of solder joint with polymer collar.