Failure Analysis of Leakage Current for Multilayer Printed Circuit Board
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TECHNICAL ARTICLE—PEER-REVIEWED
Failure Analysis of Leakage Current for Multilayer Printed Circuit Board Xiang Wang . Wangping Wu . Dingkai Xie . Peng Jiang . Zhizhi Wang . Yi Zhang
Submitted: 23 June 2020 Ó ASM International 2020
Abstract The leakage current phenomenon of a commercial ten-multilayer printed circuit board (PCB) occurred. Preliminary examination shows that there was a short circuit between the PIN_2 and POUT_4 networks of the PCB measured by a high-resistance meter, after a hightemperature aging treatment. In this case, microstructure and morphology of several layers for PCB sample were observed by optical microscopy, scanning electron microscopy and three-dimensional imaging x-ray microscopy. The chemical composition of the layer was determined by energy-dispersive spectroscopy. After observation and analysis, the results show that the leakage current failure cause of the PCB was that the metal powder impurities were found between the layers of PIN_2 and POUT_4 network, which caused the drop in the electric resistance between the two networks, resulting in the occurrence of the leakage current. The chemical composition of the impurity was only composed of copper. Keywords Printed circuit board Leakage current X-ray Failure analysis
Introduction Printed circuit board (PCB) is a kind of layered composite material, which is superimposed by conductors and insulators through special processing. As the carrier of
X. Wang W. Wu (&) D. Xie P. Jiang Z. Wang Y. Zhang Electrochemistry and Corrosion Laboratory, School of Mechanical Engineering, Changzhou University, Changzhou 213164, People’s Republic of China e-mail: [email protected]
electronic devices, PCB mainly plays the role of support, interconnection and signal transmission of electronic components, which has the dual characteristics of structure and function. Therefore, PCB is the core component of all electronic products. Along with the development of electronic industry, PCB applications become more and more prominent. As the electronic products are designed to be thinner and smaller, the reliability and stability of PCB products need higher requirements, which could maintain a stable electrical property in various application environments [1]. PCB can be classified into three categories, based on its construction and physical characteristics, namely (1) rigid, (2) flexible and (3) rigid–flex boards. Rigid PCB can be further categorized in terms of circuit complexity. Circuit density can force the design to be single sided, double sided or multilayered [2]. A singlesided board has circuit layout on one side only, while the double-sided board has artwork on both sides. A multilayered board has artwork on one or more internal layers in addition to the top and bottom layers. The connections between the two layers are made with small conductive holes called vias. The increase in the number of PCB layers makes the circuit more complex, which leads to a variety of PCB failure problems, such as open circuit, short circuit, environmental
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