Facing the neck of EUV lithography machine, can Tsinghua’s new light source really bring curves to overtake?

2022-07-25 0 By

EUV lithography machine has become a bottleneck technology in China’s chip industry. Everyone is wondering why only ASML company in the Netherlands can produce this kind of lithography machine.Tsinghua University has developed a new extreme ultraviolet light source, can help domestic lithography machine overtake on curves?I’m Eastside Starwatch, once again taking you through the lithography dilemma.For more hardcore science, don’t forget to follow me.Extreme ultraviolet lithography is a revolution in lithography. It is not easy to develop extreme ultraviolet lithography and enter the field of chip production.Prior to euV lithography, all photolithography techniques were based on lenticular refraction techniques to complete the projection of patterns.Lenses are becoming more accurate, objective lenses are becoming more and more complex, and the knowledge of optical refraction is almost done to the extreme.All of a sudden, I had to switch to the EUV lithography machine. There were no transparent lenses to concentrate THE EUV light. All the original lenses were no longer usable.Originally, an important parameter to determine the resolution, the numerical aperture has reached 1.35 (the larger the value, the better the performance), so that the resolution of the lithography machine is obviously less than the wavelength of the irradiation light, with the EXTREME ultraviolet lithography machine, the numerical aperture needs to start from 0.1, slowly close to 1.The photoresist, which has been very mature and accurate, can no longer be used, and new photoresist needs to be developed.Originally, the case of photoengraving machine can do dustproof, UV engraving machine not only dustproof but also air, because uv light and air reaction.The original transparent lens can be used for a long time as long as it is dustproof, but the euV mirror should not only be dustproof and air proof, but also be cleaned regularly, because there are always some pollution substances will be impossible to prevent adsorption on the lens (these pollution substances come from the photoresist being irradiated).For reflector cleaning alone, you can find a lot of research papers on the Internet.Moreover, the euV light source with high power and small size becomes the main obstacle to the development of EUV lithography machine.If the light source power is low, not only the imaging effect will be reduced, the working efficiency will be greatly reduced, thus improving the production cost.Nikon ultra Ultraviolet lithography machine is put on the power of the light source.ASML took advantage of the EXTREME Ultraviolet light source technology in the United States and acquired a light source company in the United States, leading Japanese companies in light source development.In fact, Nikon, as the world leader in the research and development of lithography machine, has not invested less energy than ASML in the research and development of EUV lithography machine.However, the US chip industry suffered the loss of Japan in the 1980s and was almost left behind by Japan.In order to restrict the Japanese chip industry, no longer take the path of the 1970s and 1980s.The United States has excluded Nikon from the EXTREME Ultraviolet lithography consortium, which was formed in 1997.In the EUV alliance, after the technology was basically mature, there was no suitable lithography machine manufacturer in the United States to turn the technology into a product.Nikon and ASML were brought in, but ASML was chosen for well-known reasons.ASML has collected technical support from the United States and the European Union, and received direct investment from Intel, TSMC, Samsung and other customers. After the prototype is produced, it is directly sent to TSMC for production test.ASML has a huge advantage over Nikon, which relies largely on Japanese technology, to break through first.Nikon was not a complete failure from the start.Nikon has even produced two generations of engineering prototypes, not much slower than ASML.If we stick to it, even if it is slower than ASML, we can produce qualified products.Unfortunately, lithography is a small niche market, especially high-end lithography, and the global demand is not great.ASML’s success left Nikon with very little market space. If Nikon does not give up, more money will be wasted.Nikon had to cut back on photolithography and focus more on digital cameras.ASML’s success, strictly speaking, was not the success of one company, but the triumph of American technology over Japanese technology.Since they use so much American technology, it makes sense to be restricted by the US.China’s EUV lithography machine research is not blank Back to China, our country in the lithography machine research and development, has not stopped investment (even start not late).According to data published in domestic research papers, as early as the end of last century and the beginning of this century, many Chinese scientists devoted themselves to the research of euV-lithography related technologies.As early as 2002, the first extreme ultraviolet lithography prototype has been developed, which can achieve 0.25 micron resolution.In 2008, supported by national 02 special project, changchun Institute of Optical Machinery, Tsinghua University, Harbin Institute of Technology, Shanghai Institute of Optical Machinery, Institute of Microelectronics, East China University of Science and Technology, Beijing Institute of Technology and other research institutes carried out research on high resolution EUV lithography technology.The project was completed in 2017, and the ultra-violet lithography machine has a resolution of 32nm.What is the extent of the follow-up research and development? I have not seen relevant reports. I believe I will not give up easily.That is to say, China is not completely unable to produce ULTRAVIOLET lithography machine, not to mention no ultraviolet lithography related technology.However, limited by the production process of spare parts and lack of experience in the industrial production of lithography machine, the accuracy level of ASML was not achieved.One of the obvious shortcomings should be the EXTREME ultraviolet light source, as mentioned above, the power of the extreme ultraviolet light source is an important factor limiting the performance of the lithography machine.At present, the 300-watt EUV light source is already very difficult to implement, and because the liquid tin must be excited by a laser to produce the tin plasma to emit light, the excited tin can easily adsorb to the mirror in the lamp, affecting the life of the lamp.It can be imagined that the higher the power, the more difficult the life of the lamp to ensure.Light source is one of the main research directions in China and some achievements have been made.The potential of New Light Source in Tsinghua University When everyone is worried about domestic lithography machine, a “steady state micro-beam” technology research results of Tsinghua University, published in the British journal Nature, and the mainstream media in China reported.Compared with the photolithography light source technology in the United States, Japan and Germany, this is a new light source technology, using electron beam to light, not only easier than the existing light source technology to achieve high power, but also easier to achieve long life in principle.It is predicted that the euV light source can be produced in kilowatts (about three times the current light source), which can not only improve production efficiency, but also have excellent applications in processes below 2nm. It can be said that it is a promising light source technology.However, objectively speaking, this technology is not necessarily a sure way to help our country corner overtaking technology.Although this technology was first proposed by Chinese scientists and verified by Our scientific research team, the verification equipment was provided by Germany (the backward equipment field can not be caught up with in a day or two).Moreover, the technology is only proof-of-principle so far and is still far from commercial production.In addition, in view of the extreme ultraviolet lithography technology itself is proposed by Japanese scientists, and Japanese scientists were the first to verify, but the TECHNOLOGY was eventually advanced by the United States, and led to ASML ultra ultraviolet lithography machine defeated Nikon Japan as the only lithography machine.Similarly, just because we came up with this light source technology first doesn’t mean it will be 100% won by China, American and German scientists are also involved in this research, and they have a better industrial base.It remains to be seen who will win the deer.Fortunately, Tsinghua University has applied for the 14th five-year Special research fund to turn this technology into a practical product during the 14th five-year period.Once successful, China and Japan will be different.China is already the world’s largest chip market, and the demand for chips will continue to grow.Domestic foundry enterprises represented by SMIC and Huahong have great development space, and they can become the main customers of domestic lithography machines.Domestic lithography machines have a better chance of success than Japanese lithography machines. Once the technology approaches or even exceeds ASML, it is likely to reshape the lithography machine market.Good prospects are all in our imagination at present. At present, we are afraid that it is difficult to solve the production problem of EUV lithography machine in a short period of time.The need for domestic universities and enterprises to do research, domestic chip industry chain unite to seek a breakthrough.How many years do you think it will take for China to make a breakthrough in ULTRAVIOLET lithography? Please leave your predictions in the comments section and we’ll let time judge your predictions.