Novel built-in sensor for in-situ monitoring of temperature and thermal stress in power modules

Abstract

This paper presents a novel piezoelectric sensor, which is integrated in power modules and analyzes temperature and thermal-mechanical stress in real time. Due to the increased power density, recent power modules are often exposed to high operating temperatures. Thus, it is critical to measure temperature and (related) thermal stress in power modules. The piezoelectric sensor proposed herein is fabricated by attaching PZT pieces on a direct bonded copper (DBC) substrate. Heat from operating power devices deflects power substrates and generates thermal stress, which is picked up by in-built piezoelectric sensors optimally located at critical locations. As the sensor locations are away from heatgenerating power devices, their effects on device performance are negligible. Both simulation and experiment results demonstrate that the proposed sensor provides a very good linearity (R 2 = ~0.99) in the temperature range from 40°C to 160°C. This sensor characteristics were consistent in different measurements. Therefore, our in-built piezoelectric thermal sensor facilities reliable in-situ monitoring of temperature distribution and thermal stress in power modules experiencing high temperatures.

Instrumented chip dedicated to semiconductor temperature measurements in power electronic converters

“…Nowadays, instrumented modules are proposed by manufacturers for chip temperature estimation through on-substrate integrated sensors, close to semiconductor active parts [5]. Thus, temperature estimation in operating conditions is done using thermal models.…”