Cathodoluminescence as a technique for inspection, metrology, and failure analysis of microLED processing
MicroLEDs are an important next-generation display technology offering the potential of improved performance and lower energy consumption compared to other flat-panel technologies. However, several manufacturing processing hurdles need to be addressed to scale production to mass-market volume. MicroLED displays consist of an array of directly addressable microscopic light-emitting diodes (LEDs). A current bottleneck in production is the time-consuming need to test every LED individually and replace faulty ones. Consequently, improved process development, metrology, and inspection are imperative to increase yield.
This article introduces cathodoluminescence—a characterization technique based on optical spectroscopy in the electron microscope. We demonstrate how to apply this characterization technique to microLED arrays to improve device yield, reveal and characterize a range of process- and handling-induced defects, plus perform composition metrology in a fast, contactless way.