High-speed optical three-dimensional scanner for automatic solder joint inspection

The optical principle of a high-speed three-dimensional scan- ner that can operate at high and medium resolution was developed on the basis of confocal microscopy. It was shown that 3-D detection of surfaces, essentially independent of surface characteristics such as in- clination and reflectivity, is feasible. Shading effects were found to be negligible. A data rate of 2 Mpixel/s and a 3-D resolution of 5 to 15 m ma t 150-mm to 1.5-mm height range were achieved. In a factory a high- resolution scanner has been operating successfully for automatic solder joint inspection of multichip modules since 1994. Also, a medium- resolution system for solder joint inspection of surface-mounted devices was developed and evaluated. In view of their high inspection reliability, the developed 3-D inspection systems promise to be a powerful tool for use in production lines. © 1997 Society of Photo-Optical Instrumentation Engineers. (S0091-3286(97)02310-6)