Continuous operation at 200°C device junction temperature: the final frontier for RF power semiconductor plastic packaging

The scope of this paper discusses the challenges associated with developing and introducing plastic packages for use in high power HF (RF) transistors and ICs used for wireless infrastructure power amplifiers. The main emphasis of this paper is on the "final frontier" in producing a near equivalent (to non hermetic metal ceramic package) plastic package with a maximum operating junction temperature capability of 200°C. It should be noted that this is not a peak rating, but a continuous operating capability. In addition, some time is spent covering some of the other challenges that were overcome in the systematic development of this packaging technology, such as materials and mechanical design as well as electrical performance. The paper also provides some insight into the challenges involved with the concurrent development of reliability testing methodologies needed to validate the robustness of the packaging technology, since the targeted performance goals exceeded the requirements of traditional reliability test methods. By providing high power RF devices in plastic packages, Motorola has been able to offer its customers a cost effective alternative in cellular base-station power amplifier manufacturing.