Quantitative Thermoreflectance Imaging: Calibration Method and Validation on a Dedicated Integrated Circuit

Abstract

We have developed a CCD-based thermoreflectance microscope which can deliver thermal images of working integrated circuits. However, in any thermoreflectance experiment, the coefficient linking reflectance variations to temperature is different for each material. Calibrations are therefore necessary in order to obtain quantitative temperature imaging on the complex surface of an integrated circuit including several materials such as aluminium and polysilicon. We propose here a system using a Peltier element to control the temperature of the whole package in order to obtain calibration coefficients simultaneously on all the materials visible on the surface of the circuit. Under high magnifications, vertical and lateral movements associated to thermal expansion are corrected using respectively a piezo electric displacement and a software image shift. This calibration method has been validated by comparison with the temperatures measured with separately calibrated thermocouples and diodes placed close to the integrated resistors.

LED Junction Temperature Measurement: From Steady State to Transient State

“…The time resolution is contingent upon the minimum pulse width. To capture multi-cycle image signals, a longer CCD exposure time is configured, resulting in a substantial enhancement in the signal-tonoise ratio [100][101][102][103][104][105][106][107][108][109][110]. Figure 18b demonstrates the setting of the sampling pulse signal during the cooling process according to the Boxcar principle.…”

Transient 2D Junction Temperature Distribution Measurement by Short Pulse Driving and Gated Integration with Ordinary CCD Camera

“…The relationship between the reflectivity and the temperature of the LED chip can be linearly expressed as follows [ 27 ]: …”

Thermal imaging characterization for high frequency and high power devices

“…Hence we use different physics than black-body thermal radiation. As aforementioned, the optical reflectivity of the surface changes with changing material temperature and the relation is sufficiently linear in the temperature range of interest for electronic devices [10]. The imaging sensor, therefore, should be sensitive to visible wavelength, so that we can use ordinal and industrial grade CCD or similar technology digital imaging sensors, which provides high resolution (large number of pixels) at an affordable cost.…”