Research led by the Hong Kong University of Science and Technology (HKUST) has yielded a deep ultraviolet (DUV) micro-LED display array for lithography machines. The enhanced-efficiency DUV micro-LED — the world’s first, according to the researchers — has showcased the viability of a lower cost maskless photolithography through the provision of adequate light output power density, enabling exposure of photoresist films in a shorter time. A lithography machine is crucial equipment for semiconductor manufacturing, applying short-wavelength ultraviolet light to make integrated circuit chips with various layouts. However, traditional mercury lamps and DUV LED light sources have shortcomings such as large device size, low resolution, high energy consumption, low light efficiency, and insufficient optical power density. To overcome these challenges, the research team built a maskless lithography prototype platform and used it to fabricate the first micro-LED device by using DUV micro-LED with maskless exposure, improving optical extraction efficiency, heat distribution performance, and epitaxial stress relief during the production process. A collaborative research effort between HKUST, the Southern University of Science and Technology, and the Suzhou Institute of Nanotechnology of the Chinese Academy of Sciences has produced a DUV micro-LED display array for lithography machines. According to the researchers, the work is a key step toward independent development of semiconductor equipment. Courtesy of Hong Kong University of Science and Technology. According to professor Hoi-Sing Kwok, Founding Director of the State Key Laboratory of Advanced Displays and Optoelectronics Technologies at HKUST, the manufactured device exhibits high power, high light efficiency, high-resolution pattern display, improved screen performance, and fast exposure ability. “This deep UV micro-LED display chip integrates the ultraviolet light source with the pattern on the mask,” Kwok said. “It provides sufficient irradiation dose for photoresist exposure in a short time, creating a new path for semiconductor manufacturing.” In recent years, maskless lithography has seen a great deal of research interest due to its ability to adjust the exposure pattern, provide greater customization, and save on the cost of preparing lithography costs, Kwok said. As such, photoresist short-wavelength micro-LED technology is critical to the independent development of semiconductor equipment, he said. “Compared with other representative works, our innovation features smaller device size, lower driving voltage, higher external quantum efficiency, higher optical power density, larger array size, and higher display resolution. These key performance enhancements make the study a global leader in all metrics,” said Feng Feng, postdoctoral research fellow at HKUST’s Department of Electronic and Computer Engineering. Looking forward, the team plans to continue enhancing the performance of aluminium gallium nitride DUV micro-LEDs, improve the prototype, and develop 2k to 8k high-resolution DUV micro-LED display screens. The research was published in Nature Photonics (www.doi.org/10.1038/s41566-024-01551-7).