Yoji Nishiyama

High-speed solder bump inspection system using a laser scanner and CCD camera

We have developed technologies which inspect the shape of solder bumps. The bumps are used to solder an LSI to a printed wiring board in high-speed workstations. The inspection system developed can measure the height, diameter, and brightness of bumps at very high speed. The bump height is measured using triangulation, in which a laser beam scans the bumps, and reflected light is detected with a position sensitive detector (PSD). The diameter and the brightness are measured using a microscope and a CCD camera. The detected results are compared with CAD data. A height measurement accuracy of ±3 μm and a diameter measurement accuracy of ±5 μm were obtained. Practical inspection systems using these techniques have been created and they can inspect 2000 bumps in 60 seconds.