Chinese Optics Letters, Vol. 7, Issue 3, 03217 (2009)
Preparation of solder pads by selective laser scanning
Wenqing Shi1,2, Yongqiang Yang1, Yanlu Huang1, Guoqiang Wei1, and Wei Guo1
- 1School of Mechanical &
- 2Automotive Engineering, South China University of Technology, Guangzhou 5106402 College of Science, Guangdong Ocean University, Zhanjiang 524088
We propose a new laser preparation technique to solder Sn-Ag3.5-Cu0.7 on a copper clad laminate (CCL). The experiment is conducted by selective laser heating and melting the thin solder layer and then preprinting it on CCL in order to form the matrix with solder pads. Through the analysis of macro morphology of the matrix with solder pads and microstructure of single pads, this technique is proved to be suitable for preparing solder pads and that the solder pads are of good mechanical properties. The results also reveal that high frequency laser pulse is beneficial to the formation of better solder pad, and that the 12-W fiber laser with a beam diameter of 0.030 mm can solder Sn-Ag3.5-Cu0.7 successfully on CCL at 500-kHz pulse frequency. The optimized parameters of laser soldering on CCL are as follows: the laser power is 12 W, the scanning speed is 1.0 mm/s, the beam diameter is 0.030 mm, the lead-free solder is Sn-Ag3.5-Cu0.7, and the laser pulse frequency is 500 kHz.
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