Design, simulation and technological realization of a reliable packaging concept for high power laser bars

We introduce a new packaging concept for high power laser bars using Au(80)Sn(20)-solder on different heatsinks e.g. CVD-diamond and CuW. First the optimal thermal concept and design with the lowest possible thermal resistance is described. The thermal simulations were done by an inhouse made computer program based on FFT (Fast-Fourier-Transformation). The results of the 3D- and 2D-FEM-simulations for the thermomechanical design show a solution with low bonding stress. Design rules based on the discussion of these results including the technological limitations are described, which were used to define different alternative packaging concepts. The technological realization of these concepts is described and presented. The electro-optical characterization of such bonded laser bars gave first indications about maximum power, thermal resistance, bonding stress and reliability