In my thesis I attempted to design and realize samples for studying the resolving power of the Scanning Acoustic Microscope (SAM) of BME-ETT. This study needs samples with special buried structures composed of fine structures.
Two different sample structures were designed for the tests, thus increasing the chance to gain exploitable and evaluable results. I have also chosen independent analysis methods for the verification and validation of the results obtained by the SAM measurements.
The study of the buried aluminium thin-film based sample showed that the amplitude of the reflected acoustic wave changes according to the thickness of the thin-film layer. This effect was observed in the entire thickness range of 80-800 nm of the thin-film layer. The thinner the layer is the lower the amplitude of the reflected wave will become. However, with this sample I could not determine that this thin layers cloud reflect acoustic waves, which are detectable with the scanning acoustic microscope, on their own or not.
The study of artificially damaged (cracked, fractured) BGA solder joints showed that there was a thickness range of 400-600 nm of the cracks which did not provide the expected phase change of the reflected acoustic waves.