Evaluating the thickness of a layer or determining change in thermal characteristics with depth by thermal wave detection.

摘要

To non-destructively determine the thickness of layers deposited on a substrate by analyzing thermal waves generated in a sample, especially in integrated circuit manufacturing, the sample is subjected to heat from a focused periodic heat source which generates thermal waves and either the magnitude or phase of the thermal waves generated in the sample is measured. The values obtained are normalized relative to a reference sample. The normalized values are analyzed with respect to a theoretical model of the sample to calculate the thickness of the unknown layers. Alternatively, thermal characteristics can be determined in a sample as a function of depth. The latter approach is useful for non-destructively determining dopant concentrations or lattice defects in semicondutor devices as a function of depth beneath the surface.