Scanning Thermal Microscopy Methodology for Accurate and Reliable Thermal Measurement

Abstract

The scaling and advance of semiconductor devices exacerbate device reliability with increasing temperature dependence. There is a need for thermal characterization and measurement of these devices and materials. Resistive Scanning Thermal Microscopy (SThM) is one thermal measurement technique with great spatial and thermal resolution to be compatible with advance technology node and beyond.

However, since it is a probe based technique, topography artifacts are easily coupled into the thermal measurement due to changing effective thermal contact area between the scanning probe and the device-under-test (DUT). It is also influenced by thermal drift (which can be attributed to the environment or measurement instrument) and overall heating of the DUT during the measurement process.

This research proposed a resistive SThM system incorporating the use of double lock-in amplifiers with thermal modulation of the DUT. The aim is to minimize the coupling of topography artifacts and limiting the thermal drift to the dwell time of the thermal probe at each data collection point. A theoretical treatment of the thermal signal through the detection system is provided. Various parameters of the proposed setup such as the thermal probe dwell time and interaction of the lock-in amplifiers' time constant are also studied. The system has been successfully demonstrated on an electromigration structure without the typical limitation identified. A more accurate and reliable SThM technique for thermal analysis is realized.