Optical inspection method of lead frame using mathematical morphology

摘要

Lead Frame is a core part of semiconductor IC and is used as a conductor to transmit electrical signal. In this study, an inspection system was developed that has utilized linear cameras and a method has been proposed for an automated inspection of LF. Mathematical morphology has been employed for the inspection. A modified thinning algorithm was proposed and has been used to make a master pattern of LF. The proposed method follows three steps to evaluate the quality of product. It is the first step to place the master on an object image precisely. In next, a few points, those have abnormal gray values in the object, are extracted as defective candidates. The last work is to evaluate the candidates according to a heuristic rule of decision. The proposed method has shown a good efficiency for the inspection of LF. It has been possible to find defect in a fast way and given minimal misjudgment. The proposed method is also efficient in inspecting etched products e.g. PCB and tape BGA.