Steps towards a novel cost efficient low weight LTCC packaging technology for high-end RF applications

Abstract

The emerging of a new GaN based generation of RF semiconductors provides new challenges to the packaging technology. RF performance, circuit functionality and power dissipation create new challenges to the packaging technology with respect to low losses, electrical stability, SiP integration, thermal management and reliability. Today LTCC provides a proven packaging solution for Standard GaAs devices. Increasing the frequency, power and functionality of the systems is the driving force to investigate novel packaging solutions. This paper describes the different steps how LTCC technology can cope with these requirements. Based on a comparison between different available LTCC systems and a benchmark between DP 943 and DP 9k7, the packaging performance of the 9k7 system is in detail investigated. Technological features, relevant for RF performance, like cavities, conductor line resolution, via diameter and flatness are considered. Process capability, relevant for thermal management, SiP integration and hermeticity like brazing of heat sinks, integration of heat pipes, integrated capacitors and resistors are analyzed. The impact of novel materials for heat sink and low cost materials for metallization and brazing will be evaluated with respect to weight and cost. The progress beyond the state of the art will be demonstrated by packaging solutions recently developed for RF applications.