The full name of MEMS is Micro-ElectroMechanical System, which is a mass-produced system that integrates micro-mechanisms, micro-sensors, micro-actuators, and signal processing and control circuits up to interfaces, communications, and power supplies. A tiny device or system on one or more chips. MEMS sensors are new sensors manufactured using microelectronics and micromachining technology.

MEMS is an advanced manufacturing technology developed on the basis of semiconductor manufacturing technology using traditional semiconductor processes and materials. The interdisciplinary phenomenon is extremely obvious, mainly involving micromachining technology, mechanical/solid acoustic wave theory, heat flow theory, electronics. , materials, physics, chemistry, biology, medicine, etc. After more than 40 years of development, it has become one of the major scientific and technological fields in the world.

Processing technology:

MEMS technology is based on already mature microelectronics, integrated circuit technology and its processing technology. It has many similarities with traditional IC processes, such as photolithography, thin film deposition, doping, etching, chemical mechanical polishing, etc., but some complex microstructures are difficult to implement with IC technology and must be fabricated using micromachining technology.
Micromachining technology includes silicon micromachining technology, surface micromachining technology and special micromachining technology. Body processing technology refers to a process of etching a silicon substrate along the thickness direction of a silicon substrate, including wet etching and dry etching, which is an important method for realizing a three-dimensional structure. Surface micromachining uses a thin film deposition, photolithography, and etching process to deposit a structural layer film on a sacrificial layer film and then remove the sacrificial layer release structure layer to achieve a movable structure.
In addition to the above two micromachining technologies, MEMS manufacturing also widely uses a variety of special processing methods, including common methods including bonding, LIGA, electroplating, soft lithography, micro-die casting, micro-stereolithography and micro-EDM processing. Wait.

Application materials:

Silicon-based materials: Most of the integrated circuit and MEMS raw materials are silicon (Si), a magical Group VI element that can be extracted from silica in large quantities. What is silica? The popular point is sand. After a series of complicated processing, Sand Jun became a monocrystalline silicon, which looks like this:This long, large pillar can be 1 inch (2.5cm) to 12 inch (30 cm) in diameter and cut into layers of 500 μm silicon(English: wafer). This looks like:

 The silicon-based material has excellentelectrical properties. The strength, hardness and Young's modulus of thesilicon material are comparable to those of iron. The density is similar tothat of aluminum, and the thermal conductivity is close to that of molybdenumand tungsten. If a single MEMS sensor chip has an area of 5 mm x 5 mm, an 8inch (20 cm diameter) wafer can cut about 1000 MEMS sensor chips, and the costof sharing each chip can be greatly reduced.

 Non-silicon materials: Inrecent years, MEMS materials have been gradually replaced by non-siliconmaterials, and academic researchers are now focusing on the development ofpolymer and paper-based micro devices. Devices developed with these materialsare not only environmentally friendly, but also simple to manufacture and lowin cost. Relative to silicon materials, they have significantly reduced theR&D budget. Innovations in many polymer and paper-based microdevices pointto medical applications where biocompatibility and material flexibility areessential requirements.  The development of functionsand performance of paper-based and polymer micro-devices is still at arelatively early stage, and the production facilities for such devices have notyet been developed. The maturity and commercialization of these newtechnologies may take more than 10 years. Therefore, there is still a lot ofinnovation work to be done on the research of micro-devices based on siliconmaterials, otherwise it will face the risk of development stagnation. Technical advantages: The use of MEMS technology tomanufacture sensors, actuators or microstructures is characterized byminiaturization, integration, intelligence, low cost, high performance, andmass production. The production capacity is high and the yield is high. MEMStechnology has enabled tens of thousands of MEMS chips (some processes willalso process integrated circuit chips in the same step) on each wafer, as shownin the following figure.

 This batch process is now fully automated, which isolateshuman factors and ensures that process tolerances between each MEMS chip are tightlycontrolled, increasing yield. After slicing and packaging, it becomes a MEMSchip. In appearance, most MEMS chips and integrated circuit chips are similar. In summary, the micron-sized feature size allows MEMSsensors to perform functions not possible with some conventional mechanicalsensors. It is the main force of miniature sensors and is gradually replacingtraditional mechanical sensors. It is widely used in various fields such asconsumer electronics, automotive, aerospace, machinery, chemical andpharmaceutical. Common products include pressure sensors, accelerometers,gyros, electrostatically actuated light projection displays, DNA amplificationmicrosystems, and catalytic sensors.