On the basis of analysis on vision systems for IC packaging

the micro-imaging systems

vision system calibration and pattern recognition locating algorithms are explored to realize the whole establishment of vision positioning system of IC packaging equipment. Aiming at characteristics of IC packaging

an experimental facility of vision system is established

and the system calibration is carried out. A series of pattern recognition locating programs are written with Matlab

and experiments are undertaken to analyze the precision and stability. Experimental results indicate that the calibration errors meet the requirement of normal distribution. The average errors of XY directions are 0.014 5 and 0.106 5 pixel

and the variances are 0.310 3 and 0.277 5 pixel. After system calibration and locating experiments by using a kind of IC chip

results show that the positioning error is less than 3.5 μm(0.4 pixel). The vision system has achieved a sub-pixel precision.