Control of adhesion force for micro LED transfer using a magnetorheological elastomer

Liquid crystal display and organic light emitting diode (LED) account for most of the display market. Globally, micro LED has gained wide attention. A microchip must be moved on the substrate correctly to mass-produce micro LED displays. The original method of moving microchips uses a polymer stamp to control adhesion, such as changing contact force and separation velocity. However, this method causes the problem of repeatability. In this study, a stamp is produced based on biomaterial engineering that controls the characteristic of the material surface using microstructures. The magnetorheological elastomer is used, which can control mechanical properties according to the magnetic field. Furthermore, the possibility of the pick and place process for microchips is analyzed.