IEEE Access, Preprint, 2019, DOI:10.1109/ACCESS.2019.2892231

Simulation and experimental verification of edge blurring phenomenon in microdefect inspection based on high-frequency ultrasound

Lei Su 1,2, Xiaonan Yu 1, Ke Li 1, Xingyan Yao 3, and Michael Pecht 4
1 Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology, Jiangnan University, Wuxi 214122, China
2 State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
3 Chongqing Engineering Laboratory for Detection Control and Integrated System, Chongqing Technology and Business University, Chongqing 400067, China 4Center for Advanc
4 CALCE, Center for Advanced Life Cycle Engineering, Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20740, USA


Acoustic micro-imaging based on high-frequency ultrasound has been widely and effectively used for microdefect detection in microelectronic packages. With the miniaturization of microelectronic devices and the reduction of defects, edge blurring occurs in high-frequency ultrasonic scanning and directly affects the detection accuracy and signal-to-noise ratio, especially in spherical structures such as ball grid arrays, wafer-level chip-scale packaging, and flip-chip solder bumps. This study depicts the ultrasound interaction behaviors and the edge blurring effects during microdefect imaging, which provide a theoretical basis for improving the defect detection accuracy in subsequent research. A microdefect finite element model was developed to simulate scanning in acoustic microscopy imaging. C-lines and C-scans of microdefects of various sizes were obtained, which can identify the location and size of the defects more easily. Further, an improved method to obtain the acoustic propagation path map was developed for analyzing the acoustic energy transmission during detection. Different energy consumption paths around the microdefect lead to differences among the C-lines. The different sizes of microdefects show different blurred edges in the Cscans. The experimental data and simulation show consistent results, which prove the credibility of the developed method.

This article is available online here.

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