プリント基板の Cu ダイレクトレーザ加工における 高速度カメラ画像に基づく 2 色法温度モニタリングとその CFD 解析 Temperature monitoring with a high-speed camera based on two color method and its CFD analysis in Cu direct laser drilling of printed circuit board AbstractIn the present report, we attempt to monitor the temperature of Cu direct laser drilling process of multi-layer printed circuit board with a high speed camera based on two color method and to construct a model of its process with a CFD (computational fluid dynamics). We look at the via-hole drilling using a CO2 laser beam for the FR-4 type insulation layer, which made of glass fiber reinforced epoxy resin plastics, as build-up layer. First, we estimate the temperature distribution at the time line of process including the penetration of Cu layer on the surface and the cooling of drilled hole wall after laser drilling. Second, we discuss a CFD model for the drilling process based on finite volume method. As a result, it can be seen that the monitored results is in good agreement with the calculated ones by CFD model.

In the present report, we attempted to construct a useful monitoring method to control laser via-hole drilling process of multi-layer printed wiring boards with a high speed video camera.Cu direct laser drilling was performed for the FR-4 type insulation layer, which made of glass fiber reinforced epoxy resin plastics, with a CO 2 laser beam. First, we discussed the influence of laser irradiating conditions on the drilled via-hole quality based on estimating the visible video camera images. Second, we focused on two-color method to visualize the temperature distribution in monitoring image. As a result, the high speed video monitoring and the temperature visualization in video image are found to be effective to control the via-hole quality in laser processing.

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