Introduction

Electronics are used in a wide range of applications including computing, communication, biomedical, automotive, military and aerospace. They must operate in varying temperature and humidity environments including indoor controlled conditions and outdoor climate changes. Moisture, ionic contamination, heat, radiation and mechanical stresses are all highly detrimental to electronic devices and can lead to device failures. Therefore, it is essential that the electronic devices be packaged for protection from their intended environments, as well as to provide handling, assembly, electrical and thermal considerations.

Currently, more than 99% of microelectronic devices are plastic encapsulated. Improvements in encapsulant materials, and cost incentives have stretched the application boundaries for plastic electronic packages. Many electronic applications that traditionally used hermetic packages such as military are now using commercial-off-the-shelf (COTS) plastic packages. Plastic encapsulation has the advantages of low cost, smaller form factors, and improved manufacturability.

With recent trends in environmental awareness, new environmentally friendly or ' green' encapsulant materials (i.e. without brominated additives) have emerged. Plastic packages are also being considered for use in extreme high and low temperature electronics. 3-D packaging and wafer-level-packaging (WLP) require unique encapsulation techniques. Encapsulant materials are also being devel

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