Thermal characterisation of power modules

This paper describes the thermal characterisation of power modules by means of a Variable spreading angle model extended to multilayer structures. The model is used for thermal resistance calculation of assembled chips as a function of their size and according to the module construction and structure. This way of presenting thermal data is very useful to module manufacturers and users, allowing them to carry out an easy estimation of the thermal performance before building or ordering the module, so they can conform better to the application. Moreover, due to the closed form nature of the model, it can also be used for a quick estimation of the influence of the different parts and materials that constitute the module, in order to optimise its final structure. Experimental measurements carried on modules assembled with die of known sizes show good correlation with the calculations. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.