SBIR Phase I: Monolithic CMOS-Integration of Electroplated Copper MEMS Inertial Sensors

Insense Inc, Palo Alto CA

Investigators

Abstract

The broader impact/commercial potential of this project can lead to a revolution in the consumer electronics market (mobile handsets, tablets, game consoles and wearables), wherein high performance, low power, small footprint multisensing (not limited to inertial sensing) platforms with timing devices, are all directly microfabricated on a common ASIC substrate. Sensor fusion can produce unprecedented user experiences by using data collected from all sensors and processed using machine learning algorithms. This can further boost the sensor and timing markets that are expected to exceed $6 billion dollars by 2017. Moreover, the emergent Internet of Things (IoTs) and wearable markets are expected to reach $20 billion dollars by 2025, which can induce a rapid growth of such intelligent sensor fusion market. This can have a tremendous societal impact as wearable devices and IoT systems, interfaced with mobile platforms, can be used to monitor people?s health, safety and energy consumption. Making these solutions affordable will make it amenable to low income households not only in the US but also around the world. It will also enable researchers to attain new frontiers of knowledge such as in digital sensory systems. The long-term goals are to provide such intelligent sensor fusion solutions. This Small Business Innovative Research (SBIR) Phase I project seeks to demonstrate wafer-scale microfabrication of Micro-Electro-Mechanical Systems (MEMS) inertial sensors directly on the application specific integrated circuit (ASIC) substrates, by using electroplated copper (e-Cu) as a structural material. MEMS inertial sensors, such as gyroscopes and accelerometers, are pervasively used in consumer electronics and automotive industries. Current trends are, however, requiring higher device performance with smaller footprints, wherein multi-degree-of-freedom sensors are integrated on the same package, to enable new capabilities and user experiences. These requirements can be met by monolithically fabricating inertial sensors on ASIC substrates, which is complex to achieve with silicon as a structural material. Using e-Cu, which is currently used for ASIC metal interconnects, as the structural material, can enable easier routing to implement optimized mechanical structures, smaller dimensions given the high density of copper, extremely low cost as no wafer bonding is required, smaller form factors, multiple sensors on a single die, and much smaller parasitics providing low noise and higher performance. Phase I tasks will be to wafer-scale fabricate and characterize e-Cu gyroscopes and accelerometers with optimal performance parameters and address any drift problems that could emanate from structural reliability issues associated with the MEMS elements.