Chip-type single-resistor piezoresistive pressure sensor with self-package structure

Abstract

The invention discloses to a chip-type single-resistor piezoresistive pressure sensor with a self-package structure and relates to a pressure sensor. The pressure sensor comprises a chip main body, a piezoresistor, connection anchors, a metal layer, a mosaic circuit, a printed circuit board, electrodes, tin soldering and a pressure cavity, wherein the chip main body is provided with a glass wafer with a cavity, and a silicon film; the glass wafer is combined with the silicon film in an anodic bonding manner; the piezoresistor is arranged on the lower surface of the silicon film; the metal layer is sputtered onto the connection anchors; the connection anchors form an ohmic contact with the metal layer; the mosaic circuit is connected with the piezoresistor and the connection anchors respectively; the mosaic circuit is arranged on the surface of the glass wafer; the electrodes are arranged on the printed circuit board; copper electrodes on a chip are connected with the electrodes by the tin soldering to form a Wheatstone bridge; the piezoresistor is electrically connected with external welding pads by bonding interface extraction electrodes; and the mosaic circuit outputs a signal in the sealed pressure cavity to an external circuit. The pressure sensor is highly reliable, and applicable to harsh environments such as humidity, acid-alkaline and static electricity.

Description

technical field [0001] The invention relates to a pressure sensor, in particular to a chip-type single-resistance piezoresistive pressure sensor with a self-encapsulation structure. Background technique [0002] In various application fields of sensors, temperature, flow, pressure, and position are the most common test parameters. Among all kinds of sensors, because the pressure sensor can be widely used in the measurement and control of pressure, height, liquid flow, flow velocity, liquid level, and pressure, it has become a type of sensor with the most mature sensor technology and stable performance ratio. According to different working principles, pressure sensors can be divided into mechanical diaphragm capacitive, silicon diaphragm capacitive, piezoelectric, piezoresistive, optical fiber, surface acoustic wave, Hall effect pressure sensors, etc. The piezoresistive pressure sensor is favored by people because of its simple structure, large output signal, and simple sign...

AI Technical Summary

Problems solved by technology

Although this method solves the problem of negative voltage generation to a certain extent, due to the instability of mass production, the external circuit resistance required by each sensor is different, requiring a lot of manpower and material resources to match these resistances, which greatly increases Cost of production

[0005] 2) Varistors are susceptible to pollution and corrosion from the external environment

This solution not only increases the manufacturing cost, but also the temperature change will cause the expansion or contraction of the silica gel, which will affect the sensitivity and stability of the pressure sensor output

[0007] 3) The pressure-welded gold wire connecting the sensor chip and the external circuit is susceptible to breaking or falling off due to environmental vibrations

Due to the small area of ​​the pad and the extremely thin welding wire, it is easy to cause the wire to break or fall off in a vibration environment

If the pad area is increased and the circuit is connected using soldering technology, the sensor size must be increased, resulting in a reduction in the number of sensors fabricated on the wafer and thus an increase in cost

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