Laser trimming method of zeropoint resistor of pressure chip of ceramic pressure sensor

Abstract

The invention relates to a laser trimming method of a zeropoint resistor of a pressure chip of a ceramic pressure sensor, which is characterized by comprising the following steps: firstly, respectively connecting a trimmable resistor on the two bridge arms of Wheatstone bridges in series; secondly, applying 5V direct-current voltage to the Wheatstone bridges; thirdly, carrying out real-time measurement on voltage values between the two electrodes of the Wheatstone bridges by utilizing a high-precision digital voltameter, i.e. connecting the anode of the high-precision digital voltameter with connecting points between the two fixed resistors of the Wheatstone bridge of each side and connecting the cathode of the high-precision digital voltameter with the cathode of a power supply to respectively carry out measurement to obtain the voltage values U1 and U2 of the two Wheatstone bridge; and fourthly, inputting the measured two voltage values U1 and U2 into a laser trimmer, comparing the two voltage values, and trimming the resistor required to be trimmed by utilizing a laser beam the light spot area of which is not greater than 0.0484mum<2> to make (U1-U2) = 0+ / -0.5mV. The invention has high degree of automation, good consistency and high product qualification ratio and improves the production efficiency by more than 20 times.

Description

technical field [0001] The invention relates to a sensor technology, in particular to a method for manufacturing a ceramic pressure sensor, in particular to a laser trimming method for the zero-position resistance of a pressure chip of a ceramic pressure sensor. Background technique [0002] As we all know, current pressure transmitters mainly use diffused silicon pressure sensors and strain gauge pressure sensors as the core components. Due to the poor corrosion resistance of the medium, the diffused silicon pressure sensors must be assembled into oil-filled cores and sealed with stainless steel. This not only Increase the cost and make the hysteresis performance of the pressure transmitter worse, and the strain gauge sensor has the disadvantages of poor stability and large temperature drift. These two kinds of pressure sensors are difficult to meet the needs of technological development, resulting in their application fields being greatly affected. limit. [0003] In rece...

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Problems solved by technology

[0006] The purpose of the present invention is to solve the problems of poor precision, low efficiency and low yield in the production process of the existing ceramic pressure sensor, which rely on manual grinding to adjust the zero-position resistance in the production process of the existing ceramic pressure sensor. Laser trimmer-based ceramic pressure sensor pressure chip zero resistance trimming method using laser trimmer to quickly perform one-time cutting

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