Abstract: The invention relates to a method and device for simultaneously measuring multiple properties of a sample composed of multiple layers of films. The measurement features several steps. First, at least one source of excitation radiation irradiates the sample's surface to excite an acoustic mode. A probe source of radiation irradiates the acoustic mode and is diffracted off the surface of the sample to form a signal beam. A detector detects the acoustic mode to generate a signal beam, which is then analyzed to determine an acoustic frequency and an amplitude, a depth of modulation, or a decay constant. These properties are then further analyzed to determine of at least two properties (e.g., a thickness of two layers) of the sample.

Abstract: Film thickness variation is measured in a region determined to be particularly non-uniform. Preferably the region is a donut entirely disposed within 15 mm of the edge of the film. Preferably the measurements are effected by and ISTS apparatus. The method is particularly well adapted to copper films deposited by ECD.