Spatially and temporally resolved thermal imaging of cyclically heated interconnects by use of scanning thermal microscopy

Abstract

A scanning thermal microscope with a Wollaston probe was used to investigate the spatial distribution and temporal variation of temperature in interconnect structures subjected to thermal cycling. The probe, utilized in passive temperature sensing mode, was calibrated from 20 degrees C to 200 degrees C using a single-layer aluminum microdevice. Spatial measurements were performed on nonpassivated aluminum interconnects sinusoidally heated by a 6 MA/cm(2) current at 200 Hz. The interconnects were determined to have temperatures that decreased with position from a maximum located at the center of both the interconnect length and width. Time-resolved temperature measurements were performed on the same structures sinusoidally heated by a 6 MA/cm(2) current at 2 Hz. Both the peak-cycle temperature and average-cycle temperature were found to decrease with increasing distance from the center of the width of the interconnects.

Thermometry at the nanoscale

“…200 A number of developments based on new cantilevers and new AFM-based temperature measuring techniques have been stated in recent years. 43,45,[201][202][203][204][205][206][207][208][209][210] Sadat et al 23 have reported a thermometric AFM-based technique which does not require integrated temperature sensors in AFM probes. The technique allows direct mapping of topography and temperature fields of metal surfaces with $0.01 degree temperature resolution and <100 nm spatial resolution.…”

Nanoscale temperature sensing of electronic devices with calibrated scanning thermal microscopy

“…As an example, one common method for SThM calibration is based on measuring the electrical resistance of the probe while keeping it in contact with a hot-plate stage with an adjustable temperature. 24,25 Alternatively, calibration approaches based on knowing the melting temperature of materials have also been used for thermo-resistive probes. 26 In this approach, the probe is brought into contact with a material of well-defined melting point.…”