Investigation of the root causes of the artifact of scanning acoustic microscopy

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Dr. Hurtony Tamás József
Department of Electronics Technology

The acoustic microscope allows a non-destructive inspection of the sample, helps detecting internal errors, such as delaminations, cracks, voids. My task was to get to know the theoretical foundations of acoustic microscopy and the operation of the acoustic microscope. I learned to manage the department's acoustic microscope, experienced what settings create a good quality image of the sample. I illustrated the effect of parameters in quality of pictures taken with the most common method, the Cmode scanning.

For measurement I used test samples with special configured inner layer, to insight the utilities used for preparation of the samples. Determining the surface roughness of the test frames I used the contributions from the bibliography. For referencial values I used a special instrument for the surface roughness.

During the measures with the SAM, I gained a lot of experience from the optional parameters, and I got to know the factors which can modify the visualization and the fault recognition. During the examinations I used C-mode scanning with 50 and 70 MHz transducers. I valuated the pictures gained from the scatters of the soundwaves because of the surface unevennesses. Soundwaves coming from rougher surfaces to the transducer has lower intensity. I examined the phase-gate to detect the delaminations. The program often indicate pseudo-faults, which has been proven by my results. To avoid such faults it is indispensable to know the inner structure of the examined tool, and the proper C-mode scanning and also to analise the echo signal from A-mode examination. In my thesis I tried to understand and explain the rectification of pseudo failures.


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