Implementation of an Automatic Measurements System for LED Dies on Wafer

Abstract

High brightness light-emitting diode (HB-LED) has now become one of the most popular lighting device in our daily life. As the LED industry becomes prosperous, techniques for improving production efficiency become more and more important. In this paper, a system integration method was proposed and successfully realized to implement an automatic measurements and grading (AMG) system for the LED dies after the wafer has been scribed and broken. It can be used to greatly improve the speed, efficiency and accuracy in the testing process. This suggested approach combines machine vision, optical measurement instruments, and mechanical technology to create an affordable, flexible, and highly efficient LED measurement and grading system. System architecture and details on each subsystem were described and performance was evaluated. The average speed of measurement is 3.5 LED dies per second based on repeated testings and evaluations. The experimental results demonstrate the effectiveness and robustness of the proposed system. We hope the results presented in this paper can help the LED manufacturer to make more informed decisions on the design or purchase of the AMG machine.