Zhang, G, Lee, C, Harvey, DM, Ma, HW and Braden, D (2016) Finite Element Modelling for the Investigation of Edge Effect in Acoustic Micro Imaging of Microelectronic Packages. Measurement Science and Technology, 27 (2). ISSN 1361-6501

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Abstract

In acoustic micro imaging of microelectronic packages, edge effect is often presented as artifacts of C-scan images, which may potentially obscure the detection of defects such as cracks and voids in the solder joints. The cause of edge effect is debatable. In this paper, a two-dimensional finite element model is developed on the basis of acoustic micro imaging of a flip-chip package using a 230 MHz focused transducer to investigate acoustic propagation inside the package in attempt to elucidate the fundamental mechanism that causes the edge effect. A virtual transducer is designed in the finite element model to reduce the coupling fluid domain, and its performance is characterised against the physical transducer specification. The numerical results showed that the Under Bump Metallization (UBM) structure inside the package has a significant impact on the edge effect. Simulated wavefields also showed that the edge effect is mainly attributed to the horizontal scatter, which is observed in the interface of silicon die-to-the outer radius of solder bump. The horizontal scatter occurs even for a flip-chip package without the UBM structure.

Item Type:	Article
Uncontrolled Keywords:	02 Physical Sciences, 09 Engineering
Subjects:	T Technology > TK Electrical engineering. Electronics. Nuclear engineering
Divisions:	Engineering
Publisher:	IOP Publishing: Hybrid Open Access
Date Deposited:	18 Apr 2016 09:02
Last Modified:	04 Sep 2021 13:01
DOI or ID number:	10.1088/0957-0233/27/2/025601.
URI:	https://researchonline.ljmu.ac.uk/id/eprint/3465

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