LIT METHOD AND SYSTEM FOR DETERMINING MATERIAL LAYER PARAMETERS OF A SAMPLE

摘要

Determining material parameters of a sample using lock-in thermography (LIT. Applying a non-harmonic test signal to the electrical circuit of the sample layer and imaging the sample layer using infrared sensor to obtain IR images of the sample layer while the non-harmonic test signal is applied to the electrical circuit; detecting a thermal response signal obtained from the imaging being in correlation to thermal heat propagation within the sample layer; subjecting the response signal to a fast Fourier transformation (FFT) to break down the response signal into a frequency spectrum containing at least first and second harmonics signals of a base harmonic sine or cosine signal as frequency specific response signals at multiple specific frequencies; determining the phase shifts of the frequency specific response signals at the multiple specific frequencies at a heat source position; and obtaining a frequency vs, phase shift curve.