3×3 heat-flux sensor array for the thermal measurement of IC packages

This paper addresses the idea and the design considerations of a microelectronic heat-flux sensor array. It measures the partial heat fluxes on a package. This device is very useful in the compact model generation of packages, and in the qualifications of different thermal management solutions. The proposed structure of this heat-flux sensor array is as follows: we have designed a special silicon die which, in a sandwich structure, makes possible one-sided signal outputs from the surface of the die. In order to prove the usefulness and feasibility of this device, we have produced a micro 3×3 heat-flow sensor array, suitable for the thermal investigation of IC packages or other structures, both in steady state and transient case. The surface of one sensor covers A = 5×5 mm. The applied substrate was lightly doped p-type, homogeneous, single-crystal silicon. We have already tested this array in a sandwich structure between a transistor and a cold-plate, and thus we could measure the heat-flow on the different array elements of the sensor in steady as well as transient states.