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1 Introduction
This paper demonstrates the advantages of operating a central corporate investigative service for resolving major costly electronic product issues. The Product Assurance Response Centre (PARC) was created approximately ten years ago with a view to providing rapid investigations of component and product failures. It was appreciated that an in-house facility would afford a deeper understanding of the root cause of electronic failures, avoid duplication of effort across the business, and produce a vast information knowledge base accessible to all clients.
To illustrate the typical analytical approach adopted, and the benefit of the outcome from over 6,000 investigations already undertaken in PARC, this paper describes some representative failure events. These demonstrate the benefits of operating a novel dedicated multidisciplinary facility, (chemistry, physics, metallurgy and engineering) capable of addressing the breadth of electronic failures associated with complex state-of-the-art defence and aerospace products, particularly integrated circuits, printed circuit board assemblies and hybrid devices.
Various analytical techniques are used to determine the cause of a failure; these include optical microscopy, X-ray radiography (Figure 1 [Figure omitted. See Article Image.]) ([3] Hellier, 2001) and scanning electron microscopy (SEM), with energy dispersive X-ray spectroscopy (EDX) for the determination of the elemental composition of materials (Figure 2 [Figure omitted. See Article Image.]) ([2] Goldstein et al. , 1992).
2 Silicon integrated circuits
Common causes of failure in silicon integrated circuits are over voltage caused by electrostatic discharge ([6] Vinson and Liou, 1998) or supply voltage transients and over current caused by short circuits elsewhere in the system ([1] Galler et al. , 1999; [4] Martin, 1999). The symptoms of these failure modes are quite distinct and easy to identify.
2.1 Over voltage
Over voltage refers to the presence of a voltage sufficiently high to damage or destroy a device by causing it to operate outside its allowed voltage range. This usually results in some physical damage to the circuitry, which can be observed. The over voltage can result in holes in the insulating layers used in device construction. The amount of damage depends on the energy or heat generated at the fault site.
The first example is a CMOS integrated circuit device that was giving a faulty output on one particular pin. The ceramic package was opened to expose the...