Study on parallel scheduling of LED dies measurement and grading

The light-emitting diode (LED) is the world´s most efficient light source being mass produced today. However, the packaging cost is relatively high, which has been the main factor restricting widespread application of LED lighting. As the LED industry becomes prosperous, short time consumption for single die measurement is particularly concerned by semiconductor manufacturers. Parallel scheduling methods used for speed improvement are put forward. Focusing on the cooperation between tester and prober, techniques on command flow communication between up station and motion control board, simultaneous control of X/Y driven shafts and up driven dovetails, parallel scheduling between testing process and positioning process are discussed in detail. Using these methods, average speed of measurement is improved from 2.5 LED dies per second to 5.2 LED dies per second. With experimental results, it is proved effective and efficient for proposed system. Such method is available for all similar equipments.