Real-time temperature measurement during a laser annealing process featuring a microthermocouple array: Exploiting nano and micro-metrology

Abstract

We report on the acquisition of a real-time in situ surface thermal profile over a silicon substrate exposed to a laser beam, featuring a sub-mm spatial resolution, simultaneously recorded in six different sample points. A thin-film microthermocouple array was lithographed on the silicon substrate, featuring N-type probes. A specific design of the PCB holder assembly, connected to the sampling chip by a spring-lead array, allowed a fast sample replacement after experiment. The physical conduction parameters relative to NiSil and NiCroSil thin thermoelectric films were extrapolated preparing a real-time resistance experiment during high vacuum thermal evaporation of the two alloys, exploiting a resistivity profile with sub-nanometre resolution. Information acquired during this experiment was used to derive the thermoelement properties and allow sensor calibration. The laser used to anneal the sample was a diode pumped solid state system. Numerical simulations confirmed the relevance of experimental data.