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 manufacturing method of a ceramic pressure sensor, in particular to a laser trimming method for the zero resistance of the pressure chip of the ceramic pressure sensor. Background technique [0002] As we all know, the current pressure change transmitter mainly uses the diffusion silicon pressure sensor and the strain gauge pressure sensor as the core components. Due to the poor corrosion resistance of the medium, the diffusion silicon pressure sensor must be assembled into an oil-filled core and sealed with stainless steel. It increases the cost and makes the hysteresis performance of the pressure transmitter worse, while the strain gauge sensor has the shortcomings of poor stability and large temperature drift. limit. [0003] In recent years, ceramic pressure sensors are gradually replacing traditional diffused silicon pressure sensors and strain gauge pressure sensors due to their ex...

AI Technical Summary

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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