Researchers from Pohang University of Science and Technology (POSTECH) developed a new transfer process based on a new adhesive technology, that is highly suitable for microLED mass transfer. In fact the researchers demonstrated how the technology can be used to attach and detach microLEDs from source wafer to a display substrate.
The researchers used a shape memory polymer (SMP), and created sharp nanometer-sized protrusions on the material. The researchers explain that normally the SMP surface is rough and has weak adhesion, but after applying heat and pressure, the surface becomes flat, resulting in significantly increased adhesive strength. By applying heat again, the SMP surfaces returns to its original rough state, with its reduced adhesion.
The researchers say that this technology generates strong forces of about 15 atmospheres when attaching and has the ability to fall off naturally without extra force during detachment. The difference in adhesive strength between attachment and detachment is over 1000 times.
