Micro-Raman Temperature Profiling Microscopy:
Micro-Raman temperature measurements utilize an active laser probe and spectrometer to observe the frequency of vibrational modes in semiconductor materials. The frequency is temperature dependent and, therefore, can be used to determine localized temperature at the focal spot of the laser. This spatial resolution of the laser probe approach is dependent on the laser wavelength, allowing a spatial resolution of almost an order of magnitude over passive IR techniques. Passive IR cameras or single point detectors have high temperature resolution, ~ 0.10C. However, the MWIR wavelengths utilized limit the spatial resolution to ~2 microns.
Backside Micro-Raman Temperature Display of 6x6 Array with 2μ Step Size - Silicon Digital IC
Researchers at the University of Bristol were able to demonstrate an order of magnitude improvement in spatial resolution by monitoring the line shift of the Raman scatter from a semiconductor substrate. Temperature resolution is lower and acquisition times are longer than for passive IR cameras. Standard arrangement utilizes a passive detector for global temperature mapping followed by a Raman line scan to extract further spatial detail in areas of interest.
The University of Bristol developed this technique, and QFI has commercialized the technology.
The solution has been directly integrated into QFI’s laser scanning head. 523 nm and 1340 nm versions are available.
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