The Path to Lowest Cost of Ownership for MicroLED Display Manufacturing

As MicroLED displays move from prototype to production, there is a near-zero tolerance for dead pixels, which can be easily detected by the human eye. Meeting this requirement demands accurate transfer and placement of millions of micron-scale components, each of which carries the potential to kill yield through transfer damage or placement error. Conventional assembly techniques have been challenged by these requirements, resulting in a rush to develop new assembly techniques that maximize yield, facilitate defect repair, and support throughput several orders of magnitude greater than today’s best-in-class approaches. Laser-based LLO/LIFT is now a fait accompli for MicroLED panel assembly tools as evidenced by announcements from at least 5 major capital equipment companies. Critical to the LIFT process is the Transfer Material, which needs to both hold the MicroLEDs securely without drift prior to release, then when activated by the LIFT process, cleanly release and propel the MicroLEDs towards the substrate without damage and with no residue. This presentation will show how a photopolymer transfer material specifically engineered to support the LIFT process can achieve sub-micron placement accuracy while enabling additional optimizations in the entire subsystem, resulting in the lowest Cost of Ownership. For example, a lower activation energy supports the use of a lower-cost laser, and masks can be used to facilitate mass transfer without adding complexity to the positioning stages. These optimizations of the LLO system have a direct impact on yield, throughput, and cost.