With gold prices steadily going up in recent years, copper wire has gained popularity as a means to reduce cost of manufacturing microelectronic components. Performance tradeoff aside, there is an urgent need to thoroughly study the new technology to allay any fear of reliability compromise. Evaluation and optimization of copper wire bonding process is critical. In this paper, novel failure analysis and analytical techniques are applied to the evaluation of copper wire bonding process. Several FA/analytical techniques and FA procedures will be discussed in detail, including novel laser/chemical/plasma decapsulation, FIB, wet chemical etching, reactive ion etching (RIE), cross-section, CSAM, SEM, EDS, and a combination of these techniques. Two case studies will be given to demonstrate the use of these techniques in copper wire bonded devices.

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Integrated power devices (IPD, IC+MOSFETs) have gained popularity for their excellent power management performance and compact size. During the development, it was soon found that exposing the multi-die device for debug could be challenging. In the article, we will show how the traditional decapsulation method fails to expose the device properly for follow up analysis. We will then present a new technique using laser ablation + chemical/plasma etch that proves to work for IPD products. We will then present a complete FA example combining this decapsulation technique and many other advanced FA techniques to solve an elusive failure during the development phase of an IPD product.