MEMS technology has gained a lot of significance in the automotive, biomedical, and industrial sectors. Most of the MEMS devices are smaller than the diameter of human hair strands. MEMS technology integrates mechanical aspects, sensing, and physical movement.
Micro electro-mechanical systems are miniature devices that amalgamate electrical and mechanical properties. The desirable mechanical properties include high stiffness, high-temperature stability, chemical inertness, high fracture strength, and fracture toughness.
Why Silicon material is used in MEMS technology?
One of the most abundant materials used in semiconductor technology is Silicon. Its valuable electrical properties and unique mechanical properties accommodate mechanical structures. Able to sense vibration, displacement, rotation, acceleration, angular rate, and other physical and environmental properties. MEMS used in sensor and actuator applications must exhibit piezoelectric and piezoresistive properties.
Unlike CMOS, MEMS technology lacks a standard process. Leading manufacturers like ST, Bosch, and Analog Devices have their proprietary technology.
Fabrication of MEMS involves addition and subtraction of the two-dimensional layer. Some of the methodologies include chemical and physical vapor deposition, epitaxy, and dry etching.
Classification of MEMS manufacturing process
1) Bulk micromachining
2) Surface micromachining
3) High aspect ratio micromachining
Some of the proprietary technology from leading manufactures includes ThELMA technology from ST. This facilitates the creation of a microscopic mechanical system that enables superior performance required for high-end sensors.
For any semiconductor technology, design integration is crucial at high-level integration and performance in a small form factor. MEMS technology is far more complex than CMOS-based IC design. Packaging for MEMS-based technology must protect the device from external environment damage and mitigate unwanted external stress. Exorbitant stress can damage the functionality of the device.
Most of the MEMS devices from different manufacturers are unique, thus the packaging also varies accordingly. CMOS-based technology does have a standard packaging, MEMS technology from ST uses a dual-chip system-in-package approach, assembling separate MEMS and ASIC dice in the same package. Through-Silicon Via technology(TSV) developed by ST offers greater space efficiency and interconnect density compared to other packaging techniques.
Applications of MEMS technology
MEMS technology finds potential usage in accelerometer, gyroscope, digital compass, inertial measurement unit, MEMS microscope, pressure sensors, temperature sensors, proximity sensors, and humidity sensors.
Many gaming enthusiasts may not be aware that the gaming console control is driven by new generation low power motion sensors built using MEMS technology. Game consoles such as Nintendo and Sony Playstation feature MEMS motion sensors.
An autonomous vehicle must know where it is and where it is going. GNSS performance varies in urban canyon conditions from the incorrect location due to reflections. A 6 DoF inertial measurement unit integration to GNSS enables positioning in situations with reduced GNSS reception. It also enables the improvement of GNSS accuracy from the scale of meters to centimeters.
Miniaturization, precision, and low power consumption are crucial for sensors embedded in consumer devices. TE connectivity’s MS5839-02BA sensors are ultra-compact, chlorine resistant, digital pressure, and temperature sensors optimized for applications where chlorine and saline are present.
Image Courtesy: te.com
The robust, gel-filled design enables operation in a harsh environment. This sensor offers advanced water resistance, chlorine resistance, and board-level design delivers accurate sensing. Typical applications include shallow diving computers, swim watches, underwater vehicles, and diving components.
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