A super resolution lithography equipment for producing chips below 10nm comes out
Domestic semiconductor chips highly depend on imports, especially high-end memory, flash memory processor and so on which can’t be completely home-made. As domestic semiconductor lags the most in manufacturing, it is known to all the importance of lithography machine in chip making while the Dutch ASML company having a monopoly in the development and production of high-end lithography machine.
The super resolution lithography equipment, a national key equipment researched by Institute of Optics and Electronics, Chinese Academy of Sciences, has passed acceptance check. A major achievement of this project is ultraviolet super resolution lithography machine developed by Chinese scientists, which produces 22nm chip by 365nm wave and chip below 10nm by multiple exposures.
According to Chinese Academy of Sciences, Luo Xiangang, a researcher who is director of the Institute of Optics and electronics and chief scientist of super resolution lithography equipment project, said the academy undertook the task on development of this national key equipment. After 7 years of research, project group has overcome technical difficulties including high uniformity lighting, super resolution lithography lens, nano resolution focus detection and clearance measurement, as well as ultraprecise and multi-degree of freedom workbench, without any help of foreign mature experience. The first ultraviolet super resolution lithography equipment with highest resolution, uses 365nm wave as light source, whose line width resolution of single exposure is up to 22nm(about 1/17 wavelength of expose). And on this basis, project group will develop processes including high aspect ratio etching and multiple graphical and process of pattern with characteristic dimensions below 10nm in the future, combining with project of super resolution lithography equipment.
The world’s first super resolution lithography equipment with highest resolution is based on surface plasma superresolution, which breaks limits of wavelength and traditional line pattern in lens numerical aperture. There is a brand new technical path of superresolution nanolithography from theory, equipment to process, with proprietary intellectual property rights, which provides manufacturing tool for transforming strategy field, such as matamaterial, metasurfaces, the third generation of optical element and generalized chips.
Checking and accepting expert said that all technical indicators of super resolution lithography equipment developed by Institute of Optics and Electronics, Chinese Academy of Sciences achieve or exceed specified assess indexes, with key technologies reaching international advanced level in super resolution lithography. Breaking through the resolution diffraction limits in theory, the project find a new path in developing nanolithography equipment with high resolution and large area. It bypasses intellectual property barrier of super resolution lithography equipment to realize Chinese original technical innovation. Thus, super resolution lithography equipment with proprietary intellectual property rights and autonomous and controllable technology comes out, which is the world’s first ultraviolet super resolution lithography equipment with highest resolution.
Meanwhile, there have been a series of nanoscale devices produced by super resolution lithography equipment, such as large aperture thin membrance mirror, SNSPD, Cherenkov radiation devices, biochemical sensing chip, supersurface imaging and so on, which verifies its processing capability of nanoscale devices achieving practical level.
K1 is a constant which differs from various lithography equipment. Λ refers to wavelength of light and NA refers to numerical aperture of objective lens. Thus, its resolution depends on the wavelength and numerical aperture. The shorter wavelength is and the larger NA is, the higher resolution ratio will be and more advanced processing will be.
Although it is called as lithography equipment which is developed by Chinese Academy of Sciences, the reason why it break limits of lithography equipment relying on wavelength and numerical aperture is it has a different principle. The lithography equipment system is based on super diffraction of surface plasma, bypassing intellectual property barrier of super resolution lithography equipment to realize Chinese original technical innovation.
It isn’t the first time to innovate in lithography for Chinese Academy of Sciences. There are at least 2 lithography groups in Chinese Academy of Sciences. The one is Changchun Institute of Optics,Fine Mehcanics and Physics, who makes prospective study of project in special 32-22nm equipment technology. They focus on research of EUV/ X-ray imaging technology so studying EUV light source, ultra-smooth surface, EUV multilayer and EUV imaging techniques, which is in same technical direction with ASML.
The Chinese Academy of Sciences achievement is optical lithography about super diffraction of surface plasma. In fact, the exposed 22nm lithography equipment is nothing new because there have been related reports in 2017, where it is called SP lithography equipment, the world’s first lithography equipment realizing 22nm in a single image. Now the project has passed its acceptance check.
The lithography equipment developed by Chinese Academy of Sciences can produce 22nm chips by 365nm light, which will produce chips below 10nm with the help of multiple exposures in the future. However, although it is highly-skilled in technology, it is advised not to hold moderated expectations about it. Being different from ASML system, it has to change technological processes to adapt mass production, which has a long way to go for commercial production. It has problems both in how to commercialize it and whether there will be semiconductor company adopting this new type of lithography equipment or not.
In the end, the lithography equipment developed by Chinese Academy of Sciences has a technical significance which will open up new lithography path while Chinese semiconductor technological level is not only depending on whether lithography equipment advanced or not.