Plastic Hermetic Packages for MEMS , MOEMS & Optoelectronic Devices ?

Introduction The full hermetic package for electronics and optoelectronic (OE) devices was first developed in the 1800’s and has served these industries well. The earliest optoelectronic devices, cathode ray tubes (CRT) demonstrated in the late 1800’s, used a sealed glass vacuum enclosure. The Braun Tube, for example, was a scanning CRT display system that used a glass envelope to seal out the atmosphere and maintain the required vacuum. Later, electronic vacuum tubes were developed, starting with the Fleming diode that also used a glass envelope. A few years later, De Forest introduced the triode (Audion) that was able to amplify, making it the first active electronic device. Many of the early OE and electronic devices required a vacuum to operate because the flow of electrons through free space was part of the mechanism. Today, only a small minority of products requires a vacuum. Yet, the century-old tradition of the full-hermetic sealed enclosure has continued for many products. Figure 1 shows an early hermetic package used for one of the first electronic devices.