ASML, the world's only maker of EUV lithography chipmaking tools, has never shipped an EUV tool to its primary Chinese customers due to the Wassenaar arrangement and the most recent export regulations, it doesn't mean that Chinese makers will never be able to build their own EUV chipmaking tools. This week, it turned out that Shanghai Microelectronics Equipment (SMEE) had applied for a patent covering an EUV lithography machine, reports the South China Morning Post.
The patent, which was submitted by SMEE in March 2023, focuses on 'extreme ultraviolet (EUV) radiation generators and lithography equipment.' Based on the SCMP's description, SMEE is attempting to patent the key set of components of an EUV tool: a laser-produced plasma (LPP) EUV source. An LPP EUV source comprises a CO2 light source that is applied to tiny tin droplets around 30 microns in diameter in a special chamber to create ionized gas plasma at electron temperatures of several tens of electron volts, which is then collected with a special mirror coated with several layers of molybdenum and silicon to selectively reflect the of 13.5 nm EUV light.
Shanghai Microelectronics Equipment (SMEE) is China's leading producer of lithography equipment. For now, the company supplies customers in China with its most advanced litho tool, the SSX600, which can be used to make chips on 90nm, 110nm, and 280nm process technologies. Last year, the company said it was on track to demonstrate a 28nm-capable system in 2023, though it is unclear whether it started mass production of this tool.
EUV lithography is used to make chips on advanced process technologies, such as 7nm, 6nm, 5nm, 4nm, and 3nm. Currently, SMIC produces processors on its 2nd Generation 7nm-class process technologies using immersion DUV lithography and multi-patterning, which is inefficient from a production cycle point of view and poses many risks in terms of yields. However, SMIC and its partner Huawei have no choice but to keep using DUV lithography with multi-patterning for 7nm and then for 5nm and maybe even 3nm-class production nodes.
SMEE's patent filing represents a significant step forward in China's efforts to develop its own EUV lithography tools. Though it is hard to say when the company will build at least one production EUV system that can be used to make chips in high volumes, it is evident that it is making strides towards EUV litho tools.
Shanghai Microelectronics Equipment is not the only company in China that has filed a patent concerning EUV lithography. Huawei filed an EUV system-related patent in China back in 2022. These patents mark an important milestone in China's push to develop independent semiconductor manufacturing capabilities. If SMEE ever produces advanced DUV and EUV tools, it will help China reduce its reliance on foreign firms like ASML and strengthen its position in the global semiconductor market.
It should be kept in mind that in many cases, patents are filed well before commercialization. An EUV lithography tool is an ultra-complex machine that uses dozens of high-tech breakthroughs made over three decades. Could SMEE make the same breakthroughs in just several years? Time will tell.
