A Steady State, Thermal Model of an On-Chip Assembly of RTD Heaters, Sputtered Sample and Microthermocouples

An experimentally validated one-dimensional (1D) steady state, analytical model has been presented in this paper for the in-plane thermal field of an on-chip assembly of a Resistance Temperature Detector (RTD), a sputtered thin film and microthermocouples (MT). The model is used to suggest a threshold condition for the design of an MT that may result in an overheating of the two cold junctions of the MT beyond the ambient temperature, as well as asymmetry between the two cold junction temperatures. A second threshold condition is suggested for the range of normalized thermal conductivities of the sputtered thin film that will have an impact on the thermal field. Such a model may be useful for preliminary design of structures to determine in-plane thermal conductivities of isotropic sputtered thin films.