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

Abstract

In 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.