Heterogeneous integration of micro-LEDs via multiple simultaneous transfer and bonding

Micro light-emitting diodes (Micro-LEDs) have emerged as next-generation display technologies because of their outstanding performance and stability. However, the assembly of Micro-LEDs with various colors, functions, and dimensions for full-color displays has been limited by the irreversible bonding between the Micro-LEDs and the backplanes. Here, we report a multiple simultaneous transfer and bonding (SITRAB) technology for the heterogeneous integration of Micro-LEDs. During the SITRAB process, Micro-LEDs were transferred and bonded onto display substrates within a few seconds through laser-induced soldering. Despite repeated infrared laser exposures, SITRAB adhesive, our bonding material, maintained its soldering capability. Therefore, Micro-LEDs from different interposers were sequentially integrated with the same backplane by repeating SITRAB. For instance, AlGaInP and InGaN LEDs were integrated onto a passive-matrix backplane, displaying a 165 pixels-per-inch image. 15 × 15 Micro-LED arrays were stitched to scale a display size by four times. Redundant LEDs were instantly transferred onto a defective display to achieve a 99.80% pixel yield. RGB Micro-LEDs with different chip thicknesses were assembled on a glass backplane to demonstrate a 32 × 32 resolution full-color display.