Heat Generation in Bond Wires

Abstract

Equations for fast and exact calculation of a simple model for heat transfer from a bond wire to a cylindrical finite mold package including nonideal heat transfer from wire to mold are presented. These allow for a characterization of an arbitrary mold/bond wire combination. The real mold geometry is approximated using the mold model cylinder radius and the thermal contact conductance of the mold/bond wire interface. For changes in bond and mold material, wire length, diameter, and current transient profiles, the resulting temperature transients can then be predicted. As the method is based on numerical integration of differential equations, arbitrary pulse shapes, which are industrially relevant, can be calculated. Very high thermal contact conductance values (above 40000 W/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> K heat transfer) have been detected in real package/bond systems. The method was validated by successful comparison with finite-element method simulations and alternative calculation methods and measurements.