High Speed and High Precision Solder Bump Inspection Method Using X-ray Fluoroscopy

This paper proposes a technique to inspect the bump height, area and volume of solder bump using X-ray fluoroscopy. Since X-ray fluoroscopy can acquire the 2-dimensional signal proportional to the thickness of a solder, it is expectable to measure a solder bump with high precision and at high speed. We introduced some image processing method to correct unevenness of image. Furthermore we introduced X-ray monitor in order to decrease the effect of X-ray fluctuation. As a result, fluctuation decrease more than 50% than without X-ray monitor. By compare to the optical measurement method, this method shows advantageous result at the viewpoint of bump coverage area and inspection speed.