Investigation of Effect of Wire Bonding Parameters on Wire Bond Loop Profile using 3-D Finite Element Model

• Main Authors: Chia - Hsin Wang, 王佳新
• Other Authors: D. S. Liu
• Format: Others
• Language: en_US
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/50752051852679153206

碩士 === 國立中正大學 === 機械系 === 89 === Thermosonic bonding still is the most commonly used technique in first level microelectronics packages. The most important factors that affect the wire looping profile during bonding process are the trajectory of the capillary and the thermo-mechanical properties of the wire. The aim of this research is to develop the experimental methods and computational models that can be used to study the profile of the wire loop through different wire bonding methods. For experimental works, method to measure the gold wire mechanical properties in the heat-affected-zone (HAZ) adjacent to the balled-bond was developed. The resulting stress-strain curve is conjunction with FEM models to simulation the wire looping process. Resultant looping profiles obtained from simulation were compared with actual wire bonding tests to verify the accuracy of simulation model. Next, we applied the FEM model to study the effect of different reverse angles on loop profile. In flat shape profile increasing second reverse angle can reduce the loop height and increasing first reverse angle can decrease the stress distribution in HAZ. Changing reverse angle did not significantly effect on triangle shape profile. Finally, thermo-mechanical properties of copper wire are measured by micro-force tensile testing and put into FEM simulation model to examine the loop profiles. Compare with gold wire loop profile, the loop height of copper wire is higher then gold wire. The achievement of this thesis can supply novel packaging to design proper loop profile to avoid wire sweep on molding process.