Three-dimensional hot spot localization

摘要

A non-destructive approach for the 3D localization of buried hot spots in electronic device architectures by use of Lock-in Thermography (LIT). The 3D analysis is based on the principles of thermal wave propagation through different material layers and the resulting phase shift/thermal time delay. With more complex multi level stacked die architectures it is necessary to acquire multiple LIT results at different excitation frequencies for precise hot spot depth localization. Additionally, the use of multiple time-resolved thermal waveforms, measured in a minimized field of view on top of the hot spot location, can be used to speed up the data acquisition. The shape of the resulting waveforms can be analyzed to further increase the detection accuracy and confidence level.

主权项

1. A method for detecting the location of heat sources buried within a sample by using Lock-in Thermography, comprising:
placing the sample on a test system; applying test signals to the sample at a lock-in frequency; while the test signals are applied to the sample, imaging the sample using an infrared sensor; detecting from the imaging lateral temperature distribution on a surface of the sample, to thereby spatially localize a hot spot; reducing the field of view of the infrared sensor to a small area around the center of the hot spot; increasing the operational speed of the infrared sensor; imaging the sample using the reduced field of view and increased operational speed of the infrared camera; calculating plurality of mean values across the reduced field of view in synchronization with the test signal lock-in frequency; and, analyzing the plurality of mean values to thereby determine depth location of the hot spot within the sample.