Ultraviolet lasers are used in backend pcb processing as well. In particular, pcb board the singulation of finished devices from the PCB panela task known as depanelingis a growing application space. The conventional method is to use a mechanical routing bit. pcb board However, manufacturers are looking to increase the depaneling throughput and reduce the cost of consumables pcb board.
While CO2 lasers are suitable for some depaneling jobs pcb board, they often leave a significant amount of charringor carbonizationon the cut surfaces. For many applications, this is unacceptable. For example, from a performance standpoint, problems arise because the carbon products can be conductive and moisture-absorbing, pcb board resulting in device failure. In addition, the carbon compounds are strongly aromatic, which is not acceptable for applications in which the product is close to a user's facesuch as mobile phones and hands-free Bluetooth headsets. Recently pcb board, Q-switched DPSS lasers in the green (532 nm) wavelength have demonstrated good proficiency for various PCB processes, including depaneling of thin-rigid-PCB materials.6 However, for best-quality results with thicker PCBs, tool suppliers are looking toward 355 nm Q-switched DPSS lasers. These lasers are now being offered at power levels and with reliability and pricing that are aligned with the demands of high-volume PCB manufacturing. Furthermore, with careful process optimization pcb board, the formation of carbon byproducts can be minimized or avoided altogether with these lasers.
The depaneling example in Fig. 5 is for an automotive application that must function in an often harsh environment of temperature and humidity extremes. The PCB device board was depaneled with a Pulseo 355-20 laser system pcb board. The laser's short-nanosecond pulsewidth and variable pulse frequency allows for controlled heat input into the material. As with many applications, there is a tradeoff between throughput and quality. For best throughput, continuous rapid scanning will cut through the links in a few seconds but with increased carbonization pcb board. If, on the other hand, a best-quality cut is desired, the process is slowed down by introducing cooling delays, which yields lower throughput but low or no carbonization (see Fig. 5b). With short-nanosecond pulsewidths at the 355 nm wavelength pcb board, the end user has the ability to tune the process so that the outcome falls at the desired point along the spectrum of throughput vs pcb board. quality, depending on the demands of the particular application.
