The unresolved problem for panel manufacturers is how to mass transfer and bond million of LEDs over to the control circuit panel. One potential solution sees the LEDs picked and placed into a larger array, to then be soldered to complete a display. The issue is that the accuracy of current pick and place manufacturing is ±34µm, which doesn’t meet the ±1.5µm accuracy requirements to place these tiny micro-LED components.

Alternative wafer production methods involve either etching LED arrays for bonding to an IC, or transferring a separate TFT layer to the LED array. These etching methods avoid the accuracy problems of chip bonding, but improving the techniques to meet the small component sizes of micro-LEDs and the demand for high resolution displays is expensive and difficult to implement. Manufacturing times are also very slow and refinement is still needed to improve yields.

Wafer bonding appears to be the most viable process in the short term. However it’s only currently suitable for low pixel volume panels, such as a low resolution smartwatch display rather than a QHD smartphone. Pick and place is likely the end goal for high resolution micro-LED displays, but manufacturing accuracy is still being refined.

Above quote from this page --
https://www.androidauthority.com/micro-led-di...ed-805148/