New Approach of Heat Transfer Characterization on Thin Si and Cu Solids.-Effects of Thermal Contact Resistance

This paper is a first step to introduce an original method that should give access, with accuracy, to the energy amount released by any kind of particles in low pressure radio frequency (RF)-plasma onto a solid surface. The starting point of the method is the calibration of a commercial heat flux microsensor (HFM) using a blackbody (BB) and according to the NIST (National Institute of Standard and Technology) protocol [Pittsa & al.,(2006)]. The calibration curve is plotted and the corresponding equation is given for the microsensor without sample. When a sample is placed in front of the HFM, assumption has to be made on its surface temperature in order to find the relationship between the HFM signal and the corresponding radiative heat flux at the sample surface. In a first approach to determine the real surface temperature, a 1D conduction model of a radiatively heated thin solid is computed using SCILAB. We demonstrate that the temperature difference between front and back faces of 0.5mm thin solids does not exceed 5.10 -3 K for both, Si and Cu samples. Secondly a 3D conduction simulation of the process is performed with COMSOL multiphysics to compute temperature and heat flux fields over the whole sample. The main studied parameter is the thermal contact resistance (Rctc) appearing between the sample and the HFM [Zhang & al.,(2006)]. Two important points are particularly detailed: the time for samples to be at thermal steady state and the heat flux values. Good agreement was found between experiments and full 3D simulations, especially concerning the heat flux collected by the HFM when it is covered by a sample. The results also indicate that realistic Rctc values are ranged from 10 -3 to 10 -1 for both Si and Cu substrates.