A Software Method to Improve Resistance Measure Precision of Laser Trimming System

Laser Trimming System is an equipment to adjust the resistance of chip resistor accurately by laser trimming. The measure precision of resistance measure system affects the precision of resistance directly. In order to reduce the influence of the measure error coming from measure system, a software method based on Wheatstone bridge is introduced to compensate measure error of Laser Trimming System. With its simple principle, the method is easy to realize and has good circumstance adaptability. Through measuring and compensating the measure error of high-precision standard resistors, the compensating values of measure error are gained automatically. The measure error of all trimmed resistor can be reduced using these compensating values. If measure system has good stability and low fluctuating, its application can guarantee the following precision of measure system: ±0.5⁰/₀₀ (when R<100 ¿), ±0.2⁰/₀₀ (100 ¿ ¿ R < 1M ¿), ±2⁰/₀₀ (When R¿1 M ¿).