Passive components are the major bottleneck for the increase in the level of integration and functionality of RF transceivers for wireless communications. The research in this project is focused on micromachined electromechanical components (MEMS) susceptible to replace current passive components in RF transceivers for added flexibility, programmability and increased level of integration. The to be developed components are variable capacitors, miniaturised mechanical configuration switches and micro-mechanical filters for IF and RF frequencies. The objective is to bring this technology from laboratory experiments to wide industrial use. Co-integration of MEMS with ICs on the same silicon substrate, a mass-production compatible assembly technology as well as innovative RF transceiver architectures taking full advantage of the new components will be developed.
A new technology based on micro-machining (MEMS technology) has been shown to be suitable for the fabrication of passive components that could be useful for the design of RF transceivers. These components are namely adjustable capacitors, high-Q inductors, low-loss switches and high-Q micro-electro-mechanical resonators. The aim of this project is to bring this technology from isolated laboratory experiments to broad industrial use. In order to fully exploit the potential of the MEMS components, all aspects from technology to transceiver architecture are addressed. ST Microelectronics has the clear objective to use the results of MELODICT for high-volume production of the micromachined RF components. In 2003, a production of 5 million MEMS pieces is expected, ramped up to 80 millions in 2005. Siemens will use RF-MEMS components to design and produce re-configurable multi-standard communication systems.
DESCRIPTION OF WORK
Three important components have been identified which are crucial to the reduction in size, to the flexibility and to the power consumption of RF transceivers: adjustable linear capacitors, miniaturised RF-switches and micro-electro-mechanical filters. Target specifications for these components will be established from a circuit and system point-of-view. Metal-micromachining will be used for adjustable capacitors and RF switches, while poly-silicon micro-machining has been retained for electro-mechanical filters. Assembly and co-integration of circuits and MEMS are crucial for RF applications. Co-integration of CMOS/SOI and polysilicon micro-machined MEMS will be developed, as well as a wafer-to-wafer welding technique suitable for packaging of MEMS in mass-production prior to assembly with ICs. This technique will also be used for vacuum-encapsulation of the vibrating structures (electro-mechanical filters). Components will be evaluated on the component, circuit and system-level with respect to criteria such as yield, reliability and suitability for wireless transceivers. An experimental reconfigurable multi-standard transceiver will be designed and evaluated to demonstrate the usefulness of the MEMS components. The research work will mostly be done at the three participating research institutes. ST Microelectronics will secure that industrial issues will be taken into account in the specification, in the process and in the characterisation of the MEMS components. The manufacturability and reliability of the devices is a major concern. ST will also fabricate filter samples and realise some of the process steps for the other MEMS components. Siemens will guide the work with respect to usability in wireless systems and participate in the system design.
Funding SchemeCSC - Cost-sharing contracts
20041 Agrate Brianza