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

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Micro light-emitting diodes (Micro-LEDs) offer superior performance for next-generation displays.
• Current Micro-LED assembly methods face limitations in heterogeneous integration due to irreversible bonding.

Purpose of the Study:

• To introduce a novel multiple simultaneous transfer and bonding (SITRAB) technology for Micro-LED heterogeneous integration.
• To demonstrate the capability of SITRAB for full-color display assembly and yield improvement.

Main Methods:

• Developed SITRAB technology utilizing laser-induced soldering for rapid Micro-LED transfer and bonding.
• Employed a specialized SITRAB adhesive that maintains soldering capability after repeated laser exposure.
• Sequentially integrated Micro-LEDs from different interposers onto display substrates.

Main Results:

• Achieved heterogeneous integration of Micro-LEDs within seconds using SITRAB.
• Demonstrated successful integration of AlGaInP and InGaN LEDs, achieving a 165 pixels-per-inch image.
• Scaled display size by four times through stitching 15 × 15 Micro-LED arrays.
• Improved pixel yield to 99.80% by transferring redundant LEDs onto defective displays.
• Assembled a 32 × 32 resolution full-color display using RGB Micro-LEDs with varying chip thicknesses.

Conclusions:

• SITRAB technology provides a versatile and efficient solution for Micro-LED heterogeneous integration.
• The method enables the creation of high-resolution, full-color Micro-LED displays and enhances manufacturing yield.
• SITRAB overcomes previous assembly challenges, paving the way for advanced Micro-LED display applications.