Locating Mini LED Die for Sorting
Ensure an accurate and efficient sorting (binning) process
Wafer testing systems create a map of all the mini LED die on a wafer, capturing key attributes, such as physical and surface defects, pass/fail, brightness, and color for each die. Following the die mapping process, machines sort (bin) the individual mini LED die based on quality. These high-speed machines use the previously created die map to locate die that meet a given set of criteria. Robotic micro-gripper systems pick the located die off the wafer and place them on the output collector for further processing. The cycle repeats for the next set of sort criteria.
Sorting systems use machine vision and pattern-matching vision tools to locate each targeted die and share its position on the wafer with the machine so it can be picked. Because mini LED production is high-volume and automated, speed is critical. Traditional vision tools use pixel-based contrast to locate an object; however, there are often tradeoffs where speed must be compromised to achieve high-resolution accuracy. Also, the wafer surface may have scratches or contaminants or have an elevated level of reflectivity that hinders rapid accurate die location.
Cognex VisionPro software provides robust, accurate, and fast die pattern location for mini LED sorting to help avoid these problems. The PatMax patented geometric pattern-finding vision tool, locates variable die patterns and aligns the micro-gripper for a clean pick-up. It locates die with high accuracy and repeatability, ensuring reliable equipment performance throughout the mini LED manufacturing process. With Cognex, OEMs (original equipment manufacturers) can achieve high-speed alignment that optimizes the pick-and-place process and increases overall equipment effectiveness.