Spectral microthermography for component discrimination and hot spot identification in integrated circuits

Area of Science:

• Optics and Photonics
• Materials Science
• Electrical Engineering

Background:

• Hot and cold spots in integrated circuits indicate thermal anomalies.
• Identifying these spots is crucial for assessing thermal integrity and preventing defects.
• Existing methods may lack the resolution or versatility for precise defect identification.

Purpose of the Study:

• To demonstrate an efficient and versatile spectral microthermography technique.
• To identify hot and cold spots in the active layer of biased integrated circuits.
• To assess the thermal integrity of layer structures and locate potential defect sites.

Main Methods:

• Uniformly illuminating the active layer with a tungsten lamp.
• Scanning the reflectance image across a grating-prism pair (GRISM) spectrometer to create a spectral map.
• Deriving a reflectance gradient map by comparing reflectance with and without voltage bias, which is proportional to the temperature gradient.

Main Results:

• Successfully generated gradient maps for a photodiode array and a light-emitting diode.
• Demonstrated the technique's ability to identify hot and cold spots.
• Showcased the differentiation of two semiconductor materials based on their reflectance spectra.

Conclusions:

• Spectral microthermography is an effective method for identifying thermal anomalies in integrated circuits.
• The technique aids in assessing thermal integrity and predicting defect formation.
• The method offers versatility and can distinguish between different semiconductor materials.