Reusability: Multi-Function in Electronic Assembly Equipment

Since the advent of surface mount technology, and the ultra-miniaturization of electronic assemblies, first level component packaging has continued to migrate towards surface mount technology components with higher density I/O counts, finer pitched lead frames, and direct chip-on-board capability. Surface mount technology process engineers are being required to design innovative new processes to support the manufacturability of future products incorporating high density packaging. The tool set which engineers select to support the automated assembly process of high density electronics differs from traditional surface mount technology equipment . Different assembly techniques will be incorporated to produce reliable product with high process yields. One of the challenges associated with high density packaging is how to manage the placement and reflow of the components onto the printed wiring board. Forced with this endeavor, surface mount technology process engineers are requesting equipment manufactures to produce more accurate and more flexible assemblers that are capable of handling both advanced packages and standardized surface mount devices. Flexible assembly equipment for surface mount technology and advanced packaging reduces lead times, speeds up time to market for new products, and eliminates lengthy and expensive retooling. These endeavors to address the evolving new generation of high density surface mount technology components, and the related automated assembly tooling that has the accuracy of open architecture needed to take an electronics firm into the 21st Century.

Thermal Control

Thermal control has become a critical factor in the design of electronic equipment because of the recent trends in the electronic industry towards increased miniaturization of components and device heat dissipation. A great demand on the system performance and reliability also intensifies the needs for a better thermal management. The further evidence of importance of thermal consideration to an electronic system is due to the survey by the U.S. Air Force indicating that more than fifty percent of all electronics failures are caused by the undesirable temperature control. This reviews the recent technologies in thermal control and management of electronic equipment .

The continued drive towards higher reliability electronic systems necessitates ever-more vigorous attention to the analysis and prevention of thermally induced failures. The analysis of field-return data is a crucial element in this process and reveals distinct failure categories, as well as the importance of distinguishing between failures of perfect and defective parts. The substantially lower “activation energy” for failure of imperfect, or defective, components may drastically alter the observed thermal sensitivity. Consequently, new reliability models and figures-of-merit for packaging technologies are needed. Such models are developed for time-dependent dielectric breakdown and shear-stress failure of the die-bond material.

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