Silicon micro resonant type pressure sensor and manufacturing method thereof

Abstract

The invention discloses a silicon micro resonant type pressure sensor and a manufacturing method of the silicon micro resonant type pressure sensor, relates to a pressure sensor and provides a silicon micro resonant type pressure sensor which is based on synovial membrane damping and a double pressure membrane structure, and a manufacturing method of the pressure sensor. The pressure sensor comprises a pressure sensitive layer, a resonant structure layer, a vacuum encapsulation blocking layer and lead electrodes, wherein the upper part of the border frame of the pressure sensitive layer is connected with the lower part of the border frame of a resonant structure layer; the upper border frame of the pressure sensitive layer is internally provided with two pressure membranes and is provided with two cavities for holding parallel silicon islands; the top ends of the silicon islands are connected with a first transmission beam and a second transmission beam on the resonant structure layer; channels are formed between the two cavities, so that the first resonant beam, the second resonant beam, a first mass block and a second mass block on the resonant structure layer have space for free vibration; the upper part of the border frame of the resonant structure layer is connected with a lower border frame of the vacuum encapsulating blocking layer; a cavity is formed inside a lower border frame of the blocking layer; lead holes are formed on the vacuum encapsulating blocking layer; and the lead electrodes are connected with the resonant structure layer through the lead holes.

Description

technical field [0001] The invention relates to a pressure sensor, in particular to a silicon micro-resonant pressure sensor based on a synovial film damping and a double pressure film structure and a manufacturing method thereof. Background technique [0002] The silicon microresonant pressure sensor based on microelectromechanical (MEMS) technology is currently the most accurate silicon micro pressure sensor. It indirectly measures the pressure by detecting the natural frequency of the structure and outputs a quasi-digital signal. It can be directly connected to the computer and easily Composition of instruments that directly display numbers. The accuracy of the silicon microresonant sensor is mainly affected by the mechanical characteristics of the vibrating structure, so it has a strong ability to resist electronic interference and stable performance. In addition, silicon microresonant pressure sensors also have many advantages such as fast response, wide frequency rang...

AI Technical Summary

Problems solved by technology

In particular, the RPT series of silicon microresonant pressure sensors have been widely used in aerospace and atmospheric data acquisition after more than 30 years of development. The basic principle of this series of sensors is that the pressure sensitive membrane is deformed under the action of external pressure. This kind of deformation is amplified by the silicon island fixed on the pressure sensitive membrane, and then transmitted to the resonant beam connected to the resonant oscillator, resulting in changes in the stiffness of the resonant beam, which in turn affects the resonant frequency of the out-of-plane vibration of the resonant structure. Capacitance detection and other methods are obtained by peripheral circuits, thereby establishing the relationship between output frequency and input pressure, but this type of sensor needs to overcome the influence of pressure film damping due to the resonant structure, and its quality factor has a strong dependence on the vacuum degree of the package

Professor Yuan Weizheng of Northwestern Polytechnical University in my country and others invented a new silicon microresonant pressure sensor (Ren Sen, Yuan Weizheng, Qiao Dayong, Wang Yuchao, Lu Xianglian. Silicon microresonant pressure sensor based on synovial film differential structure Sensor and its manufacturing method, Chinese patent 200910023322.7), its working principle is based on sliding film damping and capacitance detection, which simplifies the manufacturing process and layout design, and reduces the requirements for high vacuum packaging, but this silicon microresonant pressure sensor Because the position of the sensitive membrane is too close to the resonant structure, the support column for amplification is too short, making the sensitivity of the sensor much lower than that of the RPT series

Images