Compared with traditional sensors, MEMS sensors, namely Microelectro Mechanical Systems, have the characteristics of small size, light weight, low cost, low power consumption, high reliability, suitable for mass production, easy integration and intelligent realization. After more than 40 years of development, they have become one of the major scientific and technological fields attracting worldwide attention. It involves electronics, machinery, materials, physics, chemistry, biology, medicine and other disciplines and technologies, and has broad application prospects.
Among many automobile sensors, more and more MEMS sensors are used. For example, MEMS pressure sensors are mainly used to measure airbag pressure, fuel pressure, engine oil pressure, intake pipe pressure and tire pressure. The principle of MEMS accelerometer is based on Newton’s classical laws of mechanics, and it is mainly used in automobile airbag system, anti-skid system, automobile navigation system and anti-theft system. Among them, capacitive MEMS accelerometers are the mainstream products in MEMS micro-accelerometers because of their high sensitivity and little influence by temperature. Micro gyroscope is an angular rate sensor, mainly used for GPS signal compensation of vehicle navigation and vehicle chassis control system; The vibration gyroscope is the most widely used one. Generally, it forms an active control system together with a low accelerometer.
With the wide application of MEMS sensors, there is a strong need to study the welding process of high-precision automotive sensors. Automotive MEMS sensor chips are mostly made of monocrystalline silicon or polycrystalline silicon or micro-silicon mass blocks, which are commonly referred to as wafers. When conducting lead welding, the lead material is usually platinum wire, with wire diameter ranging from 0.02mm to 0.3. Due to the small size of the chip itself, the smaller pad on this basis is usually 0.2-0.6mm. It is difficult to weld 0.04mm or 0.2mm platinum wire on a very small pad. It is necessary to find a suitable chip welding method.
For the MEMS sensor chip welding process, high-precision equipment is required to achieve. A friend came to me and asked me why the equipment he bought was high precision but the soldered equipment could not meet the requirements. Basically, the chip lead could not be soldered. After looking at their equipment parameters, we found that the control accuracy of the welding power supply is not enough, and the welding power supply is the top priority of a precision equipment. Resistance welding process is the fusion of resistance hot metal and metal through current, and the control accuracy of this current directly affects the welding effect. The second is the welding mechanism. The accuracy is too low, and the corresponding pressure needs to be applied when the current passes. If the pressure is too high, the wire may be broken but cannot be welded. If the pressure is too low, it cannot be welded.
This kind of chip welding method is not only used for platinum wire welding, but also for gold wire welding, silver wire welding, tungsten wire welding, etc.
Through the above introduction, I believe you have a certain understanding of the welding process of MEMS gyroscope. Ericco’s MEMS gyros are quite popular, such as Navigation MEMS Gyroscope, Stable-control MEMS Gyro, Attitude-control MEMS Gyro，If you are interested in our products and want to obtain more technical data and quotations, please feel free to contact us.