July 17, 2017: According to an LEDinside report on micro LED, mass transfer is important for micro LED manufacturing, and manufacturers need to target backplane accurately to work on improving UPH and yield.
Micro LED technology is facing certain challenges. According to research assistant manager Simon Yang, LEDinside, there are four key technologies on micro LED manufacturing—transfer technology is the challenging part of manufacturing. Driver IC, color conversion, wafer wavelength uniformity, inspection equipment and way of inspection are other challenges that need to be addressed.
LEDinside assesses the feasibility on mass production of micro LED according to Six Sigma. It the transfer yield is as per Four Sigma then the product can be commercialized easily.
In order to transfer micro LED to target backplane, the accuracy of equipment for micro LED manufacturing is required to be less than ±1.5µm. However, currently, the accuracy of existing transfer equipment (SMT pick & place) is ±34µm (multi-chip per transfer), while flip chip bonder features with accuracy of ±1.5µm (single-chip per transfer), which are failed to meet the accuracy requirements of micro LED mass transfer.
Chip bonding and wafer bonding cannot be applied to mass transfer due to low production capacity and high time cost. As a result, wafer bonding can be used to develop micro LED technology and products featuring low pixel volume with the existing machines.
In view of these challenges, initially, micro LED will be used for indoor display, smart watch and smart wearables, due to the the challenges in transfer technology.