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This paper discusses the frontier applications of ultrafast laser processing technology in the printed circuit board industry. High-density interconnect boards have characteristics of massive micro buried and blind holes. Currently, the industry commonly operates CO2 laser to produce microvias of about 100um diameter with very high processing efficiency. However, due to the pulse duration of the CO2 laser being in the microsecond order, the thermal effect of processing is significant, see Figure 1. It is difficult to achieve high-quality micro vias of 75um and below. This paper systematically studies the processing capability of lasers with pulse duration of picosecond, nanosecond, and microsecond for 50μm diameter micro blind vias on copper-clad laminate. The quality of blind vias is evaluated through characterization such as scanning electron microscopy, laser confocal microscopy, and optical microscopic. The interaction mechanism between the laser and various materials is discussed in detail. This paper discusses the interaction mechanism between laser and materials such as copper foil, glass fiber, and resin in copper-clad laminates. Heat-affected zone decreases with decreasing pulse duration. The picosecond laser can effectively remove copper foil, glass fiber, and resin with the highest precision among the three lasers. Meanwhile, picosecond laser drilling equipment can simplify the processes necessary for drilling with CO2 laser equipment. That helps offset the disadvantage of the low power of ultrafast lasers to a certain extent. The mass application of ultrafast lasers in the PCB industry will come soon.
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