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June 2015 • The PCB Magazine 59 state devices have effectively zero inertia. ESI's Third Dynamics™ patented beam positioning technology is one such example. By coupling a first level of linear stage motion with a second level of galvanometer (motorized mirrors) mo- tion, as well as a third level of solid-state de- vice motion, it is possible to achieve well-placed laser pulses at very high beam velocities, even when processing vias as small as 25 µm as well as right-angled features. Accuracy not only is achieved through pre- cise beam positioning, but also through panel scaling and warping compensation. Given that materials and drilling systems expand, contract, and otherwise warp due to thermal and humid- ity fluctuations, post-etch relaxation, roll-to- roll handler tension, and other factors, achiev- ing high accuracy relative to existing features requires alignment to those same features and calculated adjustments to the drill locations to compensate for those factors. With good align- ment between upstream and downstream pro- cesses, it is possible to enable tighter part toler- ances as well as reduce the size of via landing pads. Achieving the best tool cost of ownership involves finding the fastest process that con- sistently meets the given application's qual- ity specifications, reducing non-value-add time during which the laser is not processing, as well as reducing the system's maintenance costs. Laser-Material Interaction In order to find the fastest process to meet quality specifications, a flexible circuit manu- facturer must understand the basics of laser- material interaction and ideally also the latest techniques for processing a specific applica- tion. A good UV laser tool supplier will have a knowledgeable applications engineering team available to help teach these methods and pro- vide advice on how to optimize the processes for the given application requirements and tool capabilities. Furthermore, the tool itself should have features that facilitate easy process devel- opment for rapid deployment of new processes and log process changes for quality control. Non-value-add time can be reduced in a number of ways. Automation, whether through roll-to-roll handlers for high volume flexible circuit manufacturing or through stack han- dlers for medium-volume manufacturing, can reduce operator error and speed up loading and unloading procedures. Automated vision alignment routines are another way to reduce operator involvement and speed up alignment time. Good debris removal and optics protec- tion mechanisms can reduce both preventive maintenance and unexpected maintenance procedures and minimize laser and optics con- sumption to reduce maintenance costs. Maintenance costs and system downtime can also be reduced when the supplier has well-trained service support teams for preven- tive maintenance and troubleshooting support. On-system logging and diagnostics features aid rapid turnaround of fixes with targeted solu- tions (rather than the alternative approach of replacing parts to see what fixes the problem). Finally, given that the laser will be one of the highest-cost consumables, the supplier should have chosen a reliable laser to help achieve the lowest possible cost of ownership over the course of the system lifespan. Summary Specific market trends are driving increas- ingly more flexible circuit usage, as well as more difficult-to-process materials and features. We have evaluated three different methods—me- chanical, CO 2 , and UV laser processing—on how well they can meet the evolving needs of the flexible circuit market and demonstrated that UV laser processing is best-equipped of those three. Finally, we explored some of the most important factors to consider when choosing a UV laser processing tool. This is an exciting and evolving time for the electronics industry and flex circuit manufacturers. Make the most of it: Reach out to various UV laser micromachining system vendors and educate yourself on what you might be able to achieve. PCB Patrick riechel, MSc Mba, is product manager for flexible circuit micromachining tools at ESI. FeAtuRe STAYING CURRENT continues