摘要 |
An apparatus and method of automatically performing a calibration of the accuracy of placement of semiconductor chips or devices by a pick-and-place machine. The parts are placed on an adhesive-backed glass plate that has calibrated black marks whose dimensions match those of a specific part lead footprint. A gray scale camera mounted on the machine above the inverted glass plate records and sends a signal to a machine computer identifying the coordinates of exposed part silver lead area. The computer calculates part placement error and sends error data to a CRT or camera screen and alarm to alert an operator.
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