Design of a Control System for a Turret Based Test Handler

Final testing procedures are performed to assure the quality of manufactured parts before their shipping to customers. Turret based test handler is a general kind of IC Test Handler for final testing. This paper discusses how to develop a general control system for a test handler of turret style in which every workstation moves up and down separately based on an industrial control computer. The combination of object-oriented programming and the cycling scanning working mode is the key of the whole system. To achieve ideal performance, special control flags are designed as an efficient way for making all the workstations work as setting orders stably. The method to developing the control system in this paper can be also applied to similar systems, which would greatly reduce development cycles. A turret based test handler with this control system has passed the test of a semiconductor factory and operates well in actual production.