Optical Displacement Measurement and Mechanics Analysis for Electronic Devices under Thermal Loading

• Main Authors: Ze-Wei Lin, 林志緯
• Other Authors: Yeong-Shu Chen
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/01404968754936368213

碩士 === 元智大學 === 機械工程學系 === 90 === During the IR re-flow process of a PBGA component, it is frequently found that warpage results from the mismatch of coefficients of thermal expansion between the components and boards. The deformation always affects the interconnections between component and printed circuit board. When the interconnections failure occurs, it will affect the function of the system. The study will focus on the measurement of this warpage under the re-flow process and calculate the stresses induced on the solder balls for PBGA components. For the deformation measurement, an optical measuring system is used to take the electronic component surface data and then transfer them into the deformed shape. Both the phase stepping shadow moiré and laser displacement measurement system are used simultaneously to measure the deformation in each of the temperature settings. Base on the deformed shape, the stresses on the solder balls are calculated and then compared with theoretical which is based on the Timoshenko’s beam theory. It is found that the deformation results from both the laser sensor and shadow moiré methods are quite consistent. It also shows that laser displacement measurement method can be used on the occasions where shadow moiré method doesn’t work. Such as those where the surface is not flat or too small for being able to generate enough moiré pattern.