Near Hermetic Air Cavity Plastic Packaging for Wireless, MEMS and Optical Applications

This paper will detail the design and manufacturing elements of near hermetic air cavity packages produced by injection molding of low moisture diffusivity polymers.

The R-Pak process uses a patented sealing methodology to take maximum advantage of the properties of the starting polymeric material. The material properties and advantages will be presented.

The very low moisture diffusivity of the packages produced provides excellent environmental protection for MEMS devices and sensors or alternatively the capability to incorporate ultra clean, optically clear covers for imaging applications. The polymers also have a low microwave loss tangent which, when combined with low resistivity conductors and package bases, produce packages with outstanding microwave performance. Microwave matching structures can be also built into packages that can transform very low transistor input and output impedances to design friendly intermediate impedances. This feature minimizes package discrete components and reduces assembly sensitivity. The packages can also be designed for very high power.

The technology also offers cost advantages over many alternatives often with higher performance. Representative packages illustrating each of these features will be shown and the process and equipment developed for R-Pak packages detailed.