Engineers develop first deep-UV microLED display chip for maskless photolithography

In a breakthrough initiative that will revolutionize the semiconductor industry, the Hong Kong University of Science and Technology (HKUST) School of Engineering has developed the world’s first deep ultraviolet (UVC) micro-LED display array for lithography equipment. This efficiency-enhanced UVC microLED demonstrated the feasibility of low-cost maskless photolithography to enable faster exposure of photoresist films by providing adequate light output density.

The research was conducted under the supervision of Professor Kwok Huixing, founder of the National Key Laboratory of Advanced Display and Optoelectronic Technology at the Hong Kong University of Science and Technology, and in collaboration with Southern University of Science and Technology and the Suzhou Institute of Nanotechnology. there were. Chinese Academy of Sciences.

Lithography equipment is an important device in semiconductor manufacturing that irradiates short-wavelength ultraviolet light to produce integrated circuit chips with various layouts. However, traditional mercury lamps and deep UV LED light sources have drawbacks such as large device size, low resolution, high energy consumption, low light efficiency, and insufficient light output density.

To overcome these challenges, the research team built a maskless lithography prototyping platform and used it to fabricate the first microLED devices using deep-UV microLEDs with maskless exposure and Improved light extraction efficiency, heat distribution performance, and epitaxial stress relaxation.

Professor Kwok said, “The team has achieved important breakthroughs in the first microLED device, including high power, high light efficiency, high-resolution pattern display, improved screen performance, and fast exposure capability. This deep-UV microLED display chip “It integrates light sources,” he said. It provides sufficient irradiance to expose photoresist in a short time according to the pattern on the mask, opening a new path in semiconductor manufacturing. ”

“In recent years, low-cost and high-precision maskless lithography technology in traditional lithography equipment has attracted research and development attention because it can adjust exposure patterns, provide more diverse customization options, and save lithography mask preparation costs. “Therefore, photoresist-sensitive short-wavelength microLED technology is extremely important for the independent development of semiconductor devices,” Professor Kwok explained.

“Compared to other representative works, our innovations yield smaller device sizes, lower drive voltages, higher external quantum efficiencies, higher optical power densities, larger array sizes, and higher display resolutions. These key performance enhancements make this study a world leader in all metrics,” concluded Dr. Feng Feng, a postdoctoral researcher in the HKUST School of Electronics and Computer Engineering (ECE).

Their paper, titled “High-power AlGaN deep-UV micro-light-emitting diode display for maskless photolithography,” was published in the journal Nature Photonics. Since then, it has gained wide recognition in the industry and was selected as one of the top 10 advances in China’s third-generation semiconductor technology in 2024 by the 10th International Forum on Wide Bandgap Semiconductors (IFWS).

Looking forward, the team plans to continue improving the performance of the AlGaN deep UV microLED, refining the prototype, and developing high-resolution deep UV microLED display screens from 2k to 8k.

Dr. Feng is the first author, and Professor Liu Zhaojun, an adjunct associate professor in the ECE department at HKUST and an associate professor at Southern University of Science and Technology, is the corresponding author. Team members also include Dr. Liu Yibo, an ECE postdoctoral researcher. alumnus Dr. Zhang Ke, and collaborators from other institutions.