Abstract
This paper describes two-dimensional axisymmetric analysis of non-steady heat conduction of two-layers composed of resin and metal in laser drilling of printed circuit board. In the present analysis, resinous evaporation and diffraction of optical system for image formation were considered, and influence of diffraction on hole shape was investigated. Latent heat of evaporation and absorptivity were estimated using hole depth in experimental results. Laser intensity distribution at resin surface was estimated using the calculated result of diffraction in the experiment. Experimental hole shapes were in good agreement with analytical results considering diffraction. It was concluded that twodimensional .axisymmetric analysis considering diffraction of optical system for image formation is necessary to estimate hole shape in laser drilling of printed circuit boards.
