This Small Business Innovation Research (SBIR) Phase I project will develop RF MEMS (Radio Frequency Microelectromechanical Systems) relays for automated test equipment (ATE), wireless frontends, and other commercial applications. As the advancement of microchip technology continues, the testing and qualification of microchips become more challenging and costly. RF MEMS may enable lower cost, higher throughput and more repeatable test and qualification in mainstream semiconductor manufacturing. In particular, RF MEMS relays may offer benefits for probing of next generation 3D chips with thru-wafer vias that require sensitive and yet very rapid test capabilities. The proposed project addresses the manufacturability and packaging challenges for production. In comparison to boutique manufacturing processes utilized by many RF MEMS technologies, the proposed project leverages the proven and robust silicon MEMS production processes and infrastructure. Furthermore, packaging is performed using wafer-level hermetic packaging that addresses the high cost of hermetic sealing for RF MEMS devices. ATE applications represent the initial application of the proposed RF MEMS relay technology. Wireless applications, as well as other applications, can be enabled by lower prices as production volumes are ramped up. Anticipated results include a RF MEMS relay technology, with low-cost integrated packaging, ready and qualified for production.
The broader impact/commercial potential of this project includes ATE, wireless, and enabling RF capabilities for the scientific community. RF MEMS may offer ATE key advantages in testing next generation microchips, including improved repeatability and reliability compared to conventional mechanical relays. RF MEMS may be critical for testing next generation 3D microchips with thru-wafer-vias that require sensitive and yet high-throughput testing. For wireless, RF MEMS address reconfiguration and tuning for improved power efficiency and link robustness of radios. For example, RF MEMS may be utilized for (1) changing a reconfigurable antenna from a high bandwidth line-of-sight configuration to a lower bandwidth diversity configuration, or (2) compensating a wireless handset?s power amplifier for its changing operating environment to maintain maximum efficiency (including impedance and distance from the base station). For scientific applications, RF MEMS relays offer low insertion loss and superior linearity from DC to >100 GHz. In comparison to semiconductor transistors, RF MEMS have an approximate 10x reduction in insertion loss. Thus, a variety of radio architectures may benefit, as well as radiometers for monitoring weather and climate. Anticipated results include a RF MEMS technology, with low cost integrated packaging, ready and qualified for production.
In the last decade, numerous market studies have projected large opportunities for RF MEMS relays in wireless devices and automated test equipment (ATE). While substantial R&D investments have been made to develop components for the enormous cell phone market, there is a lack of a viable RF MEMS solution for ATE applications in semiconductor manufacturing. For ATE, the small size and power consumption of a RF MEMS relay makes it ideal for high-density board test applications compared to conventional mechanical relays and reed switches. However, currently available RF MEMS parts are 1) priced much higher than the cost necessary for broad adoption into the ATE market or 2) sold only as part of a large ATE tester, thus, MEMS relays have barely penetrated the ATE market or the use of MEMS relays has been primarily restricted to high-end RF applications in which RF MEMS relays offer additional advantages in insertion loss. The project aimed to deliver a low-cost RF MEMS relay capable of penetrating the ATE market. Three main hurdles prevent adoption of RF MEMS devices into ATE applications: cost, reliability, and repeatability. The RF MEMS relay is based on relay designs with demonstrated high repeatability, high production yields, and wafer-level packaging technology that will cost <$0.50 per device, but lacked the reliability required for ATE applications. To overcome the reliability hurdle, Laserlith integrated high temperature electrical contact materials into the relay designs. The performance and reliability results have been independently verified by a third party. Furthermore, a scalable packaging process important for cost reduction was integrated. The process can be performed at most MEMS foundries, as the critical DRIE equipment is also used for producing gyroscopes and accelerometers in smart phones. The Phase I work successfully demonstrated a microrelay that meets the reliability, cost, and repeatability requirements for the automated test equipment market and potentially the cell phone market.
