Russia's lithography machine action is 15 years late?Do you guess the fighting nation will succeed?, 10.11.2022.
The war did not give anyone a buffer, and it was on the verge of breaking out. From March onwards, the world seems to be turbulent, rushing to another unknown.
So far, it seems less important who wins and who loses. What we care more about is who can swim and who can stick to the shore when the waves of war come.
Unsurprisingly, after the start of the Russian-Ukrainian war, it was energy, then food, and now chips. After the Western world and Russia were separated, they were hit hard. Winter is coming, and looking at the future, Putin seems to have done a good job. One of the most important preparations for the cold winter is to develop a lithography machine.
It's not that Russia didn't know the importance of lithography machines before this, but it has relied on imports from the United States and the West for so many years. The research and development process is undoubtedly very difficult. In addition, the domestic electronics industry in Russia is not very developed, and the demand for the semiconductor consumer market is not strong. If it weren't for the international economic sanctions on chip suppliers, Russia would not need to invest too much in the research and development of lithography machines.
But the cruel side of war is starkly revealed that if you don't stand up for yourself, you will always be held hostage. So the Russian side announced that it will manufacture lithography machines independently.
Moreover, the upcoming maskless X-ray lithography machine will be benchmarked with ASML's EUV lithography machine, and its performance may be more advanced than EUV lithography machine.
Why did they make a maskless X-ray lithography machine, and how is it different from the current ASML EUV lithography machine?
The current status of technical application of lithography machine
At present, the lithography machine market is a typical "three-point world" pattern. (ASML), Nikon (Nikon), and Canon (Canon) have a market share of more than 90%, which is a typical oligopoly market, and ASML is monopolizing the most high-end extreme ultraviolet (EUV) lithography machine market.
Canon's lithography machines mainly occupy the mid-to-low-end market, mainly manufacturing packaging lithography machines, LED lithography machines and panel lithography machines.
Nikon's lithography machine mainly promotes ArF immersion technology. The application of EUV technology is not yet mature, and the lithography process is still far from ASML.
The status quo of lithography machines in China is still using the 193nm process technology of deep ultraviolet DUV, such as the lithography machine of the Shanghai Microelectronics Equipment Corporation (CMEE) process 90nm process, which is equivalent to the level of the Pentium four processor in 2004.
Although we can also use a DUV lithography machine to improve the performance of the chip to 7nm through multiple exposure and etching methods, but the cost is huge, the yield is low, and it is difficult to commercialize mass production. Therefore, the gap between China's lithography machine and the Netherlands, the United States and Japan is very obvious. Fortunately, a 28nm lithography machine is being developed, which is expected to achieve a pure localization process.
What is an X-ray maskless lithography machine? Why is Russia developing it?
Manufacturing lithography machines is more of a last-ditch battle out of desperation.
Russia's largest chip manufacturer Mikron has been sanctioned by the United States, and several other chip factories have also been sanctioned in all directions, so Russia announced in April that it would invest 670 million rubles (equivalent to about 51 million yuan) as a lithography machine. , and the project was undertaken by the Moscow Institute of Electrotechnical Technology (MIET), Russia.
The "maskless X-ray lithography machine" developed by MIET is a little different from the Dutch EUV lithography machine and several other lithography machines we mentioned above.
The biggest difference is the choice of light source.
ASML's EUV lithography machine is based on the principle of extreme ultraviolet, with a wavelength of 13.5nm, and the Russian region is about to develop a maskless X-ray lithography machine based on the principle of plasma source or synchrotron.
The development history of X-ray lithography machine has a long history, but it has not been formed. X-ray was first proposed to be used in lithography in 1972, because its strong penetration determines that it can also define high-resolution patterns on thick materials. After the hiatus in the 1990s, the international research on X-ray lithography has become active again in recent years, and it is becoming a hot spot in international lithography research.
X-ray is an electromagnetic wave with wave-particle duality like other particles. The wavelength of X-ray is extremely short, between 0.01nm and 10nm. From the perspective of wavelength, it is indeed superior to EUV wavelength. The shorter the wavelength, the higher the exposure resolution and the higher the writing accuracy. Therefore, Russia's vigorous development of a maskless X-ray lithography machine is likely to be a miracle.
Because of the extremely short wavelength of X-rays, serious diffraction phenomena do not occur. When we use X-rays for exposure, the choice of wavelength is limited by certain factors. During the exposure process, the photoresist will absorb X-ray photons and generate photoelectrons whose range changes successively with the change of the X-ray wavelength. These photoelectrons will Reduce the lithography resolution, the shorter the wavelength of X-rays, the longer the photoelectron range, the more unfavorable for lithography. Therefore, increasing the wavelength of X-rays helps to improve the lithographic resolution. However, long-wavelength X-rays will widen the line width of the pattern. Considering the influence of various factors, usually only the wavelength of X-rays can be selected as a compromise.
In recent years, studies have found that when the line width of the pattern is small to a certain extent (usually below 0.01 μm), it is affected by the waveguide effect, and the line width of the final pattern is smaller than the actual mask pattern, so the resolution of X-ray lithography is also Influenced by the size of the reticle-to-wafer distance.
Among the technologies of post-optical lithography, the most important and most difficult technology is the mask manufacturing technology, in which 1:1 lithography is very difficult, which is one of the difficult problems hindering the development of the technology.
IMEC's simulation research shows that with the gradual improvement of the process, the emergence of EUV and high NA EUV lithography machines also brings new challenges to masks. The impact of mask defects will become larger and larger, and mask design rules will need to become more stringent.
Therefore, in order to achieve a more flexible lithography process, the industry has begun to study replacing physical masks with other things, or even processing without masks at all. Such a method is called "maskless lithography".
That is the main direction of the Russians.
Why "maskless lithography"?
In the field of pan-semiconductor, lithography technology is mainly divided into mask lithography and direct writing lithography according to whether a mask is used or not. Direct write lithography is also known as maskless lithography.
It refers to the focused projection of a computer-controlled high-precision beam onto the surface of a substrate coated with a photosensitive material, without the need for a mask for direct scanning exposure.
As early as 20 years ago, the Moscow Institute of Electronic Technology in Russia carried out research in the field of maskless EUV. The project research of "maskless lithography machine" is progressing relatively smoothly.
As can be seen from market applications and technology trends, maskless lithography technology has been in the process of continuous evolution and exploration.
Can the X-ray lithography machine finally be realized? It's hard to tell. However, related technologies such as synchrotron radiation light source, photoresist and other processes have become increasingly mature, and are expected to play an important role in future R&D and production.
Although the Russian media is also saying that Russia's lithography machine plan is 15 years late, as netizens said, the biggest problem in Russia is the lack of money and industrial base. In theory, there is no problem. Its related research can be traced back to the last century. 80's. At that time, they were already researching and manufacturing light sources. The theoretical physicists who are currently undertaking this project are also mainly engaged in X-ray optics, optical interferometry, etc. Judging from all the existing conditions, Russia's lithography machine does not mean that just say it,
The last stand after breaking the boat is likely to end the monopoly of ASML, and expect the Russians to make history again.
Although China has invested in this field, its relative strength is relatively weak. Should it also pay close attention to the development trend of this technology, and also look forward to the early launch of China's self-developed lithography machine. When the next wave comes, I hope we can save some ability to protect ourselves or resist, that is, not to lie flat on the beach.