Thin film thickness measurements and depth profiling utilizing a thermal wave detection system

摘要

The subject invention discloses a method for non-destructively determining the thickness of layers deposited on a substrate by analyzing thermal waves generated in a sample. The methods are particularly suited for use with integrated circuit manufacturing. In the subject method, the sample is subjected to a focused periodic heat source which generates thermal waves. Either the magnitude or phase of the thermal waves generated in the sample are 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. In an alternate embodiment, thermal characteristics can be determined in a sample as a function of depth. The latter approach is useful for nondestructively determining dopant concentrations or lattice defects in semiconductor devices as a function of depth beneath the surface.