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Review
. 2019 Feb 12;12(3):550.
doi: 10.3390/ma12030550.

Copper/Epoxy Joints in Printed Circuit Boards: Manufacturing and Interfacial Failure Mechanisms

Philipp Nothdurft  1   2 , Gisbert Riess  3 , Wolfgang Kern  4   5
Affiliations
Review

Copper/Epoxy Joints in Printed Circuit Boards: Manufacturing and Interfacial Failure Mechanisms

Philipp Nothdurft et al. Materials (Basel). .

Abstract

Printed circuit boards (PCBs) have a wide range of applications in electronics where they are used for electric signal transfer. For a multilayer build-up, thin copper foils are alternated with epoxy-based prepregs and laminated to each other. Adhesion between copper and epoxy composites is achieved by technologies based on mechanical interlocking or chemical bonding, however for future development, the understanding of failure mechanisms between these materials is of high importance. In literature, various interfacial failures are reported which lead to adhesion loss between copper and epoxy resins. This review aims to give an overview on common coupling technologies and possible failure mechanisms. The information reviewed can in turn lead to the development of new strategies, enhancing the adhesion strength of copper/epoxy joints and, therefore, establishing a basis for future PCB manufacturing.

Keywords: circuit boards; copper/epoxy joints; electronic industry; failure analysis; printed; state of the art.

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Conflict of interest statement

The author declares that there is no conflict of interests regarding the publication of the paper.

Figures

Figure 1
Figure 1
Trends in regional growth of world PCB (printed circuit boards) production (1980–2016). Reprinted with permission from [1]; Copyright 2016 IPC.
Figure 2
Figure 2
Scanning electron microscopy (SEM) image of a 10k× fold magnification black oxide treated surface. Reprinted with permission from [17]; Copyright 2002 Atotech GmbH.
Figure 3
Figure 3
Schematic flow chart of the alternative oxide process.
Figure 4
Figure 4
5000× fold magnification of an alternative oxide treated surface by SEM measurement. Reprinted with permission from [17]; Copyright 2002 Atotech GmbH.
Figure 5
Figure 5
Resonating form of BTAH (benzotriazole).
Figure 6
Figure 6
Curing of epoxy resins with BTAH.
Figure 7
Figure 7
Schematic representation of the white oxide process.
Figure 8
Figure 8
Process steps for the deposition of a thin azole silane film on copper.
Figure 9
Figure 9
Cu/epoxy delamination failures after reliability testing. An SEM image of the cross section (a) and a photographic image after peeling (b) are shown.
Figure 10
Figure 10
Schematic of crystal growth.
See this image and copyright information in PMC

References

    1. IPC World PCB Production Report for the Year 2016. [(accessed on 24 January 2019)]; Available online: www.ipc.org.
    1. Garimella S.V., Fleischer A.S., Murthy J.Y., Keshavarzi A., Prasher R., Patel C., Bhavnani S.H., Venkatasubramanian R., Mahajan R., Joshi Y., et al. Thermal challenges in next-generation electronic systems. IEEE Trans. Compon. Packag. Technol. 2008;31:801–815. doi: 10.1109/TCAPT.2008.2001197. - DOI
    1. Uehara K., Sakurai M. Bonding strength of adhesives and surface roughness of joined parts. J. Mater. Process. Technol. 2002;127:178–181. doi: 10.1016/S0924-0136(02)00122-X. - DOI
    1. Sekercioglu T., Rende H., Gulsoz A., Meran C. The effect of surface roughness on strength of adhesively bonded cylindrical components. J. Mater. Process. Technol. 2003;142:82–86. doi: 10.1016/S0924-0136(03)00463-1. - DOI
    1. Shahid M., Hashim S.A. Effect of surface roughness on the strength of cleavage joints. Int. J. Adhes. Adhes. 2002;22:235–244. doi: 10.1016/S0143-7496(01)00059-8. - DOI

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