CO2 laser drilling of the resin coated copper (RCC) layers of laminated circuit boards has been investigated at different fluence levels. The threshold fluence for copper layer drilling is found to be 570 Jcm-2 for 5µm and 1500 Jcm-2 for 12µm copper thickness, using laser pulses in the 10 µs and 20 µs FWHM respectively. Undercut in the resin layer is found to primarily depend on the amount of excess energy in the pulse tail. Methods to reduce the pulse decay time have been investigated, giving smaller diameter breakthrough holes close to threshold, which should aid the control of hole drilling in RCC. High-speed videography has been used to verify the observations of post-processing analysis.
|Number of pages
|Proceedings of SPIE - the International Society for Optical Engineering
|Published - 2004
|Fiber Lasers: Technology, Systems, and Applications - San Jose, CA, United States
Duration: 26 Jan 2004 → 28 Jan 2004
- Carbon dioxide lasers
- Resin coated copper