In a significant advancement poised to transform the semiconductor sector, engineers have created an unprecedented deep-ultraviolet (UVC) microLED display array specifically for lithography machines. This state-of-the-art UVC microLED demonstrates the potential for cost-effective maskless photolithography by delivering sufficient light output power density, thus allowing for quicker exposure of photoresist films.
In a significant advancement poised to transform the semiconductor sector, the School of Engineering of the Hong Kong University of Science and Technology (HKUST) has created an unprecedented deep-ultraviolet (UVC) microLED display array specifically for lithography machines. This state-of-the-art UVC microLED demonstrates the potential for cost-effective maskless photolithography by delivering sufficient light output power density, thus allowing for quicker exposure of photoresist films.
The research, overseen by Prof. KWOK Hoi-Sing, the Founding Director of the State Key Laboratory of Advanced Displays and Optoelectronics Technologies at HKUST, was a collaborative project with Southern University of Science and Technology and the Suzhou Institute of Nanotechnology at the Chinese Academy of Sciences.
Lithography machines are essential in semiconductor manufacturing, using short-wavelength ultraviolet light to create integrated circuit chips with varying designs. However, conventional mercury lamps and deep ultraviolet LED sources present drawbacks, including large device sizes, low resolution, high energy use, poor light efficiency, and inadequate optical power density.
To address these issues, the research team constructed a maskless lithography prototype platform, which they utilized to produce the first microLED device via deep UV microLED with maskless exposure, enhancing optical extraction efficiency, thermal distribution, and alleviating epitaxial stress throughout the manufacturing process.
According to Prof. KWOK, “The team accomplished crucial milestones with the first microLED device, including high power, superior light efficiency, high-resolution pattern display, better screen performance, and rapid exposure capabilities. This deep-UV microLED display chip integrates the ultraviolet light source within the mask’s pattern, delivering an adequate irradiation dose for photoresist exposure in a brief timeframe, paving the way for a new era in semiconductor manufacturing.”
“In recent times, the development of low-cost, high-precision maskless lithography technology in traditional lithography machines has garnered substantial interest due to its capacity to modify exposure patterns, offer greater customization, and reduce the costs associated with creating lithography masks. As such, photoresist-sensitive short-wavelength microLED technology is vital for the independent advancement of semiconductor equipment,” Prof. KWOK elaborated.
Dr. FENG Feng, a postdoctoral research fellow at HKUST’s Department of Electronic and Computer Engineering (ECE), noted, “In comparison to other prominent works, our innovation boasts a smaller device size, lower driving voltage, enhanced external quantum efficiency, increased optical power density, larger array sizes, and improved display resolution. These significant performance enhancements establish our research as a leader globally across all metrics.”
Their research paper, titled “High-Power AlGaN Deep-Ultraviolet Micro-Light-Emitting Diode Displays for Maskless Photolithography,” has been published in the prestigious journal Nature Photonics. The work has gained significant acclaim within the industry and was recognized by the 10th International Forum on Wide Bandgap Semiconductors (IFWS) as one of the top ten advancements in China’s third-generation semiconductor technology in 2024.
Moving forward, the team aims to further enhance the performance of AlGaN deep ultraviolet microLEDs, refine the prototype, and work on developing high-resolution deep ultraviolet microLED display screens ranging from 2k to 8k resolution.
Dr. FENG is the lead author, while Prof. LIU Zhaojun, an Adjunct Associate Professor at HKUST’s ECE Department, who also holds the position of Associate Professor at Southern University of Science and Technology, is the corresponding author. Additional team members include ECE postdoctoral fellow Dr. LIU Yibo, PhD graduate Dr. ZHANG Ke, and collaborators from various other institutions.
