STMicroelectronics has a long history and demonstrated expertise in MEMS sensors and actuators. As the first major manufacturer to start high-volume MEMS production on 200mm wafers in 2006, ST launched the consumer MEMS revolution by making motion sensors small, accurate, and affordable through the combination of innovative product design, deep application expertise, and industry-leading process and packaging technology.
Since then ST has continued to grow and diversify its portfolio into new types of devices and application segments. Today, in addition to its successes in motion sensors for consumer markets, the company features products dedicated to automotive, industrial and medical markets with a dedicated manufacturing flow guaranteeing high quality and reliability.
Know more about our MEMS technology processes for automotive and industrial.
An industry-leading process technology
In addition to using the well-understood and valuable electrical properties of silicon, MEMS (Micro Electro Mechanical Systems) sensors leverage silicon’s unique mechanical properties to integrate mechanical structures able to sense acceleration, rotation, angular rate, vibration, displacement, heading, and other physical and environmental properties. ST manufactures its MEMS using proprietary micromachining processes that share processing steps derived from basic integrated circuit techniques. These steps produce a circuit that combines electrical circuits and 3-dimensional mechanical structures.
ST’s long-term success in MEMS has drawn upon the Company-developed, industry-leading Thick Epitaxial Layer for Micro-gyroscopes and Accelerometers (ThELMA) manufacturing process. This is a surface micro-machining process that combines variably thick and thin poly-silicon layers for structures and interconnections, enabling the integration of accelerometer and gyroscope mechanical elements in a single chip.
ST’s ThELMA technology enables the creation of tiny mechanical structures that, in combination with our strong packaging expertise in creating high-vacuum cavity and controlling the hermetic sealing of the mechanical structure, assures high reliability and great performance while offering significant cost and size benefits to customers.
Recently, ST qualified and started the production of ThELMA60, an enhanced version of ThELMA technology, implementing a 60μm surface-micromachining epitaxial layer, 3 times thicker than the standard ThELMA process. This thicker layer brings the superior performance required by high-end inertial sensors, while keeping the cost effectiveness and flexibility of the ThELMA technology. With this step ST is bridging the gap between surface-micromachining and bulk-micromachining traditionally used to manufacture high-end sensors.
An efficient integration
ST uses a dual-chip system-in-package approach assembling separate MEMS and ASIC dice in the same package.
ST is the world’s first manufacturer to have implemented innovative solutions such as Through-Silicon Via technology (TSV) in high-volume MEMS production. Deployed in volume production since 2011, the ST-patented TSV technology replaces traditional wiring with short vertical interconnects in ST’s multi-chip MEMS devices, such as smart sensors and multi-axis inertial modules.
TSV offers greater space efficiency and higher interconnect density compared with wire bonding or flip-chip stacking, enabling a higher level of functional integration and performance in a smaller form factor.
Building upon its strong experience in mobile applications, ST continues to develop its highly integrated multi-axis iNEMO™ inertial module family to serve all market needs. The modules combine motion sensors and an ultra-low power processing circuit in a System-in-Package solution to offer a lower power consumption and smaller package size versus discrete solution, while providing the high accuracy and reliability required for wearable, portable devices, mobile, handset, industrial, and positioning devices.
Managing the full design and manufacturing chain
Unlike conventional microelectronics development, MEMS compels companies to apply a unique blend of multi-disciplinary skills that combine electrical, semiconductor, and mechanical design expertise.
ST is one of the few silicon companies with the capability and experience to address and optimize the full manufacturing and testing chain: from chip specification, though architecture and design, advanced CMOS processes for ASICs, MEMS-specific front-end process, advanced packaging design and manufacturing.
This unrivaled knowledge of, and capability to control, each stage of the process uniquely qualifies ST to completely optimization the MEMS device in performance, quality, value, and reliability. It brings also to the customer enormous flexibility in its product design, as well as improved time to market.