Electronics packaging assures the power and electrical distribution, the mechanical protection, and the heat dissipation for integrated circuits. An integrated circuit (IC) package is a package that gives environmental protection to the IC chip while providing for different test methods and high-quality assembly at the next interconnection level. Packaging is often the biggest bottleneck as it controls the system’s electrical performance, cost, size and reliability.
Electronics packaging
The major trend in the electronics industry today is to make products smarter, lighter, smaller, thinner, and faster, while at the same time making them more user- and environment-friendly, functional, powerful, reliable, robust, innovative, creative, and less expensive. Factors such as the feasibility of suitable substrates have to be considered when selecting a packaging alternative. From this point of view, interconnection methods like flip-chip technology are becoming increasingly interesting.
Research has addressed the challenge of making the “smallest structures” possible. The activities were mostly basic-research oriented and have resulted in a multitude of processes and small structures. At present, increased emphasis is being placed on aspects of the devices and their industrial application. The emphasis has shifted to microsystems. This is being done in order to concentrate on functionality and performance rather than on small dimensions, as well as on highlighting the additional requirement to cover packaging, interconnection and interfaces. Even today, much research involves silicon technology.
Sensor system packaging
Packaging and production options must be considered at an early stage of microsensor development. New silicon technology cannot be commercially successful until used in products and integrated with chips, packages, circuit boards, base plates, housings, connectors, displays, and switches.
Many MEMS researchers are experienced in silicon processing and tend to concentrate on device fabrication. So there is an obvious risk that packaging is regarded as a necessity that may safely be ignored until the device is already designed and processed. It appears that packaging issues are often not taken into account until the industrialization stage of the product. This approach makes packaging very complex and expensive. Packaging must be considered from the outset of the device’s initial design. The MEMS device must be designed for packaging and assembly. In other words, it must be producible in an industrial sense.
Since MEMS often includes moving structures, the packaging requirements of such components must take this into account. Some functions also include interaction with the surrounding environment, such as pressure sensors. This imposes new requirements on packaging, since in normal microelectronics the chip must be protected completely from any impact from the environment. Packaging also provides mechanical support to the sensitive chip in order to facilitate handling and simplify assembly. The most important difference between packaging MEMS and packaging microelectronics is that MEMS is more often required to be in contact with the functional environment.
Most integrated sensors as well as integrated circuits require encapsulation in order to have mechanical support, to be protected from the environment, to be easily mounted on circuit boards and to facilitate the handling of the individual chips. In the case of MEMS, the device also needs to be protected at the wafer level from water and particle impingement during the dicing process. A higher level of integration will be required in future sensor systems becausedifferent sensor elements, electronics, complex optical elements and optical filters (in the case of optical sensors) and fluidic elements (in the case of biological and chemical sensors) will be combined.