Digital fringe projection system for measuring warpage of painted and unpainted PBGAs and boards and FEA studies of PBGA warpage

Warpage;Digital fringe projection;Laser fringe projection;Dynamic digital fringe projection;Unpainted;Chip package;PBGA;PWB;PWB assembly

Kang, Sungbum ; Ume, I. Charles Mechanical Engineering Sitaraman, Suresh K. Michaels, Thomas E. Shi, Jianjun Mello, Michael ; Ume, I. Charles

University:Georgia Institute of Technology

Department:Mechanical Engineering

关键词: Warpage;    Digital fringe projection;    Laser fringe projection;    Dynamic digital fringe projection;    Unpainted;    Chip package;    PBGA;    PWB;    PWB assembly;   

Others  :  https://smartech.gatech.edu/bitstream/1853/55486/1/KANG-DISSERTATION-2015.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

Improvements in chip package technologies have led to smaller package sizes and higher density circuitry that require superior reliability of chip packages. One of the crucial factors affecting the reliability of chip packages is warpage which primarily occurs during the reflow process. Because warpage may cause serious reliability problems such as solder bump failure and die cracking, warpage control has become a crucial task. Advancements in warpage measurement and prediction would provide important steps toward addressing this concern. Among the various warpage measurement techniques, fringe projection techniques (i.e., laser fringe projection (LFP) and digital fringe projection (DFP)) have emerged as recent trends due to their non-contact, full-field, and high-resolution (for small viewing area) capabilities for measuring the warpage of chip packages and boards (i.e., printed wiring boards (PWBs) and PWB assemblies). In this research, the measurement capabilities of a LFP system were improved by reducing its laser speckle noise and post-processing time, and a novel DFP system for measuring the warpage of painted and unpainted chip packages and boards was developed. Also, parametric studies were performed to predict the warpage of plastic ball grid array packages affected by four geometric factors. Finally, a guideline that manufacturing engineers can use for selecting the most suitable warpage measurement technique for their particular application was developed. The results of this study will help to improve the yields and reliability of chip packages and boards, reduce the manufacturing costs and time to market for chip packages and boards and ultimately reduce the prices of end-products.