A research team led by Prof. Sun Haiding at the University of Science and Technology of China (USTC) has developed a vertically integrated MicroLED array, applied for the first time in a deep ultraviolet (DUV) maskless photolithography system. The study presents a vertically integrated MicroLED array paired with a photodetector (PD) on a transparent sapphire substrate, allowing emitted UV photons to pass through the substrate and be detected on the backside. This setup includes a feedback circuit that stabilizes light output, automatically adjusting to maintain consistent intensity.
Prof. Sun’s iGaN team has refined DUV MicroLED technology, claiming to have enhanced the array’s structure and configuration for better efficiency, bandwidth, and UV detection and imaging functions. Their DUV display integrated chip employs a three-dimensional, vertically integrated design that combines AlGaN-based DUV MicroLEDs with ZnO-based photodetectors via a transparent sapphire substrate. This arrangement enables effective UV photon emission and capture, ensuring steady optical signals.
A key feature of the system is its closed-loop feedback control, which maintains consistent luminescence by adjusting light intensity as needed. This setup represents the first demonstration of a DUV maskless photolithography system using a MicroLED active matrix, achieving a pixel density of 564 PPI and enabling high-resolution patterning on silicon wafers.
“This technology introduces a new standard in photolithography and opens pathways for integrated optoelectronic systems,” said Prof. Sun. The team is now working to reduce the size of MicroLED and photodetector components to increase array density and uniformity across larger wafers, with applications in precision photolithography and photonic systems.
Reference
H. Yu, J. Yao, M. H. Memon, Y. Luo, Z. Gao, D. Luo, R. Wang, Z. Wang, W. Chen, L. Wang, S. Li, J. Zheng, J. Zhang, S. Liu, H. Sun, Vertically Integrated Self-Monitoring AlGaN-Based Deep Ultraviolet Micro-LED Array with Photodetector Via a Transparent Sapphire Substrate Toward Stable and Compact Maskless Photolithography Application. Laser Photonics Rev 2024, 2401220. https://doi.org/10.1002/lpor.202401220
