Scientists at the Hong Kong University of Science and Technology have developed a new deep ultraviolet (UVC) microLED display array for lithography, marking a major advance in semiconductor technology. The research was published in the journal Nature Photonics .
The UVC microLEDs developed by the research team provide sufficient light power density to reduce the time needed to expose the photoresist film, enabling more efficient and cost-effective maskless lithography.
The research was conducted under the direction of Professor Guo Haixing, Founding Director of the State Key Laboratory of Advanced Optoelectronic and Display Technology at the Hong Kong University of Science and Technology, in collaboration with the Southern University of Science and Technology and the Suzhou Institute of Nanotechnology, Chinese Academy of Sciences.
Lithography is important for semiconductor manufacturing because it uses short-wavelength ultraviolet light to produce integrated circuit chips with complex layouts. However, traditional mercury lamps and deep ultraviolet LED light sources face challenges such as large device size, low resolution, high energy consumption, poor optical efficiency, and insufficient optical power density.
To address these limitations, the team developed a prototype maskless lithography platform and used it to fabricate the first micro-LED devices using deep-ultraviolet micro-LEDs with maskless exposure capability. This innovation improves light extraction efficiency and heat distribution, and reduces epitaxial stress during fabrication.
The team achieved a significant breakthrough in the first micro-LED device, with high power output, high light efficiency, high-resolution pattern display, improved display performance, and fast exposure. This deep-ultraviolet micro-LED display chip integrates an ultraviolet light source with a pattern on a mask, delivering a sufficient amount of radiation to briefly expose the photoresist, opening up a new avenue for semiconductor manufacturing .
Mr. Kwok Hai-shing, Professor and Founding Director, Hong Kong University of Science and Technology
Kwok explained: ” In recent years, the low-cost and high-precision maskless photolithography technology of traditional photolithography equipment has become a hotspot of research and development, as it can adjust the exposure pattern, provide more diverse customization options, and save the preparation costs of photolithography masks. Therefore, photoresist-sensitive short-wavelength micro-LED technology is of great importance to the independent development of semiconductor devices .”
“ Compared with other representative studies, our innovation is characterized by smaller device size, lower driving voltage, higher external quantum efficiency, higher optical power density, larger array size and higher display resolution,” concluded Dr. Feng Feng, a postdoctoral researcher at the School of Electronic and Computer Engineering (ECE) of the Hong Kong University of Science and Technology. “These significant performance improvements make this research a world-leading research in all indicators .”
This research has received significant recognition from the industry and was named one of the top 10 advancements in China’s third-generation semiconductor technology through 2024 at the 10th International Forum on Wide Bandgap Semiconductors (IFWS).
In the future, the team aims to improve the performance of AlGaN deep-ultraviolet micro-LEDs, optimize the prototype, and develop high-resolution deep-ultraviolet micro-LED displays ranging from 2k to 8k.
The research team included ECE postdoctoral researcher Dr. Yibo Liu, doctoral student Dr. Ke Zhang, and collaborators from partner institutions. Dr. Feng is the first author. The corresponding author is Professor Zhaojun Liu, visiting associate professor in the School of Electrical and Electronics at the Hong Kong University of Science and Technology and associate professor at Southern University of Science and Technology.
Journal References:
Feng, F., et al . (2024) High-power AlGaN ultra-deep ultraviolet light-emitting diode displays for maskless lithography. Nature Photonics . Source: http://www.dept.gov/depts …
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The Hong Kong University of Science and Technology
