Here is the abstract you requested from the DPC_2007_Mems technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Plastic Air Cavity Package Achieves True Hermetic Performance for High Reliability Applications|
|Keywords: Hermetic, Plastic , Package QFN|
|Devices such as MEMs, HB-LEDs, and image sensors are increasingly designed into automobiles and require greater package reliability particularly in high temperature, high humidity conditions. As a result, hermetic performance is becoming more important in today’s packaging requirements. Traditional plastic transfer molded packages are mature, low cost packages but not a viable solution because of poor moisture absorption as well as other material issues such as stress and non-linear performance. Similarly, plastic air cavity packages have exposed leak paths at the lead frame-polymer interface and poor lid seal methods that fail to achieve hermetic levels. Hermetic package choices have been limited to ceramic packages yet require specific lid attach processes- low melt glass, seam weld and innovative epoxy methods in order to achieve hermetic performance. Nevertheless, high modulus, low CTE, limited flexibility and high costs have led companies to search for other alternatives. There has been a clear need for greater flexibility and improved packaging solutions that achieve hermetic performance. By combining innovative material technology, package design and unique processing, a plastic air cavity QFN has been developed to achieve hermetic fine leak performance, 5x10-8 atm cc/s He. This paper will discuss material development based on Liquid Crystal Polymer derivatives, controlling mechanical properties such as CTE, key design features and an innovative ultrasonic lid process that enable a hermetic plastic package. Performance and reliability data will be presented on 7mmx7mm and 8mmx8mm QFN’s that meet fine leak requirements and serve as a MEMS package solution for hermetic, high reliability applications.|
|Dr. Mike Zimmerman, CTO
Quantum Leap Packaging, Inc