A FPCB Cutting Process using a Pico-second Laser

Laser micromachining has increasingly been applied to the electronics industry, where a strong demand exists for the precision machining of high-density, multi-layer, and multi-material components due to the ever-decreasing size of electronic products such as cellular phones, MP3 players, and digital cameras. At present, multi-layered flexible printed circuit boards (FPCBs) are being mechanically cut with a punching die. The mechanical cutting of FPCBs causes such defects as burrs on layer edges, cracks in terminals, delamination and the chipping of layers. Here, a pico-second laser (355 and 532 nm) and a UV nano-second laser were used to cut FPCBs to examine the applicability of these types of lasers and to compare the cut quality when using them. In this study, the thermal effect and chemical change on flexible copper clad laminate (FCCL) were examined to solve problems related to surface debris and short-circuiting, which can occur as a result of a photothermal effect. The laser cutting of FCCL, which comprises the base material of a FPCB, was carried out while adjusting the variables of the peak power, scanning speed, wavelength and pulse duration. Points to which special attention should be paid include a fast scanning speed, a low repetition rate and a high peak power, al of which are required for precision machining.