Heterogeneous Micro LED Displays Yield Statistics

A Micro LED (μLEDs) display, a heterogeneous system, is one that integrates inorganic μLEDs and IGZO thin film transistors made on different substrates with different process flows. Millions of μLEDs are transferred from source wafers and integrated on TFT backplanes to make a display. To guarantee zero defect density, a fault tolerant design (e.g. redundancy) may be adopted. Here, we estimate the required redundancy level for a given display resolution and yields for the μLED source wafers and the transfer process of μLEDs to the backplane. This is done using a novel yield statistical model. The results may be used to assess the capital requirements and the risk involved in making such heterogeneous systems in high volume manufacturing.