Miniaturization of BAW devices and the impact of wafer level packaging technology

As wireless mobile applications continue to drive shrinkage of the individual components, consequently a corresponding decrease in required footprint and component thickness needs to go along with it. Over the last years, the size of power amplifier duplexer (PAD) front-end modules as well as standalone duplexers has steadily decreased. A significant portion of this shrinkage has been contributed by a decrease in BAW die size. This decrease is driven by various technology improvements. In this paper we will first discuss the introduction of on-chip capacitors. These capacitors not only allow for a reduction of the required external component count, but also for an increased degree of design freedom. Second, we will discuss how the shrinkage of reflector metal dimensions leads as a direct result to an significant reduction in die sizes. Although core technology improvements can allow for radical BAW die shrinkage, the packaging technology that comes along with the BAW die needs to contribute its share to maintain this trend. Last, a novel approach for wafer-level packaging BAW die will be presented.