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Scanning acoustic microscopy (SAM) is a powerful non-destructive testing tool used in the field of electronic package, micro-and nanomaterial and medication. The capability to distinct how minimum of defect is very important to detect the flaw in electronic packages. The detection resolution of SAM depends on the frequency of ultrasonic focus transducers. In this paper, the Multi-Gaussian Beam model to simulate the sound field of the focused transducers is discussed. Mainly the frequency domain imaging algorithm and 2D-Deconvolution method for better image quality and high resolution is analyzed. Finally, the calibration experiments for the detection resolution of 100MHZ transducer is carried out. In addition, the micro flaws with different dimensions are observed at different defocusing location. It is concluded that the detection resolution decreases with the deviating from focus plane, so the flaws should be sensitive on the focus area by precisely controlling the vertical position for better detection resolution.

Scanning Acoustic Microscopy (SAM) has been a powerful non-destructive testing tool used in electronic packaging and material characterization. With the development of 3D electronic packaging, internal dimensions of electronic packaging are getting more and more smaller, and the detection accuracy of existing non-destructive testing technology is far behind the requirements of manufacturing technology. In this study, a set of practical SAM system was developed independently by our Lab. And its detection resolution was analyzed using high frequency focused transducers with center frequency ranging from 20 MHz to 100MHz. The experimental results show that the lateral resolution of the ultrasonic transducer with 100MHz central frequency can reach about 40 microns, which is consistent with calculated resolution. Comparing with Sparrow criteria, Rayleigh criteria is more coherent with the experimental results.