Advanced automated optical inspection system for fishtail collapse of microrouter

In this paper, an innovative automated optical inspection (AOI) system is proposed to detect fishtail collapse of various fishtail images. Up to the present, there is no report on the inspection of fishtail collapse by using an AOI system. The proposed AOI system is the first system that can inspect the fishtail collapse of microrouter. The fishtail image of the microrouter was extracted first by a newly developed lighting device. We use the end gash to identify one of the blades as the reference blade, in order to provide an orientation-invariant method to solve the fishtail image rotation problem. Three invariant features of the blade are used as indicators of quality control. The blade with collapse, whose area is as small as 0.02mm x 0.02mm, could be identified based on the constructed quality control charts. Twenty-five fishtail images are used to validate the proposed AOI system. The successful detection rate of the implemented AOI system is up to 99.2%, and it demonstrates that this system detects the collapse accurately and robustly.