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.