In the field of digital technology, the autonomy of CPU and GPU has always been a pain point for us. For a long time, the high-end chips on the market have been in the hands of Intel, Invida, AMD and other companies, but the road of self-research chips in China has not been smooth, and one of the most important reasons is that the most important lithographic machine in chip production has been subject to people.
Recently, the national major research and development project "super-resolution lithography equipment development" passed acceptance. It is reported that the lithographic machine is developed by the Institute of Photoelectric Technology, Chinese Academy of Sciences. The lithographic resolution reaches 22 nanometers. Combined with double exposure technology, it can also be used to manufacture 10 nanometer-scale chips in the future.
As soon as the news came out, there was a heated debate on the Internet. Some netizens believe that this technology will bring great changes to the development of domestic self-developed chips; while some netizens believe that this lithography machine belongs to SP lithography machine, and in all aspects, it is not as good as the mainstream ASML lithography machine, but a gimmick. So, what is the performance of this domestic lithography machine?
Objectively speaking, the success of domestic SP lithography machine is an important bend overtaking in the process of chip development in China, which means that the idea of self-research chip in China will have the possibility of independent development in the future. However, SP lithography has many limitations, and its appearance does not mean that we can achieve the complete localization of chips. Therefore, this is an important step in chip research and development in China, but it should not be brazenly flattered or deliberately discredited.
First of all, although the SP lithography machine is still in the 22nm process stage, but the 22nm of this lithography machine refers to "365nm light source, a single exposure line width of up to 22nm". That is to say, in the field of optics, this machine breaks the traditional diffraction limit. This also means that the machine validates the possibility of surface plasma lithography. Although the process of this machine can not be compared with ASML lithography machine, this idea brings the possibility of the future.
Despite the complex monitoring equipment, the core principle of ASML lithography is to reduce the pattern on the mask through the objective lens system. When it comes to the imaging process, the diffraction limit of light has to be considered. Even if all geometric aberrations are left aside, an infinitesimal point will become a diffuse speckle after imaging due to the effect of diffraction, which is called "Airy speckle". Therefore, the resolution of the actual optical system imaging is the distance between two Eli spots which can be exactly separated.
Because of the diffraction effect, the imaging resolution will be limited. The final resolution depends on the parameters such as wavelength and numerical aperture. The smaller the wavelength, the larger the numerical aperture, the higher the resolution. So the main research direction of ASML in recent years is to use shorter wavelength (near-ultraviolet-deep ultraviolet-extreme ultraviolet), increase the numerical aperture (more complex objective, liquid immersion). However, every step further becomes more difficult, which puts forward more stringent requirements for system design, processing and assembly, error detection and many other aspects, and the cost is also becoming more and more high.
So what about surface plasmon lithography? Surface plasma refers to a kind of special electromagnetic wave localized on the surface of matter. With the increase of distance from the surface of matter, it decays rapidly. It is generally believed that there is no region above the wavelength level. Even more amazing is that although surface plasmon waves are excited by other electromagnetic waves, the wavelength will be greatly compressed, and the compression ratio depends on the electromagnetic properties of the material and other parameters.