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Since the rise of the concept of domestic substitution, people who pay little attention to the semiconductor industry have heard of lithography machines. At present, almost all of the most advanced chips in the world can not bypass ASML's DUV (Deep Ultraviolet) and EUV (extreme Ultraviolet) lithography machines, but they are expensive and difficult to make. Is there any other way for China to go except for the research and development of lithography machines?

In fact, lithography itself has a variety of routes, the closest to the industry is nano-imprint lithography (Nano-Imprint Lithography, referred to as NIL).

Japan most hopes on nano-imprint lithography technology, and tries to rely on it to counterattack again. Nikkei News also said that compared with EUV lithography process, the use of nano-imprint lithography process to make chips can reduce manufacturing costs by nearly 40% and electricity by 90%. Companies such as KIOXIA, Canon and Big Japan Printing plan to put this technology into practice in 2025. [1]

In this article, you will learn whether nano-imprint lithography can bypass the lithography machine, what are the advantages and disadvantages of nano-imprint lithography compared to lithography, and whether nano-imprint lithography is another way out for China.

Fu Bin | author

Li Tuo | Editor

1. Making chip nano-imprint like stamping is a kind of micro-nano processing technology, which adopts the principle of traditional mechanical mold micro-copying and can replace the traditional and complex optical lithography technology. [2]

Although from the name point of view, the concept of nano-imprinting is very advanced, but in fact its principle is not difficult to understand. Imprinting is an ancient pattern transfer technology, movable type printing is the original prototype of imprinting technology, while nano-imprinting is a kind of imprinting technology whose feature size is only a few nanometers to hundreds of nanometers.

For example, a nano-imprint lithography chip is like a seal, engraving a circuit with a gate length of only a few nanometers on the seal, and then stamping the seal on the plasticine to get the opposite pattern of the seal. After demoulding, you can get a chip. In the industry, this chapter is called template, while plasticine is called nano-imprint glue. [3]

Nano-imprint lithography (UV nano-imprint) and optical lithography are compared with Canon official website [4], fruit shell hard technology translation nano-imprint technology itself has a wide range of applications, including integrated circuits, storage, optics, life sciences, energy, environmental protection, national defense and other fields. [5]

In the chip field, nano-imprint lithography is not only good at making all kinds of integrated circuits, but also good at manufacturing 3D NAND, DRAM and other memory chips. compared with microprocessors and other logic circuits, memory manufacturers have strict cost restrictions and relaxed requirements for defects. Nano-imprint lithography technology fits it very well. [6]

For a chip, lithography is the most important, complex and expensive process step in the manufacturing process, and its cost accounts for more than 30% of the total production cost and accounts for nearly 50% of the production cycle. [7]

The process node is moving forward in accordance with Moore's Law, and so far, the industry is moving towards the nanometer limit, and the optical lithography that the industry depends on also has its limitations [8] [9] [10]:

First, SDAP and SAQP processes are one-dimensional patterned solutions, which seriously limit the layout of the design.

Second, the extra processing steps after lithography greatly increase the cost of wafer processing (including additional lithography, deposition, etching steps).

Third, the improvement of the resolution of optical lithography is mainly achieved by shortening the wavelength of the light source. Although the light source has been shortened from 436nm and 365nm of ultraviolet to 193nm of deep ultraviolet (DUV) and 13.5 nm of extreme ultraviolet (EUV), the resolution limit is about half a wavelength under the optical diffraction limit.

Fourth, the shortening of the wavelength of the lithography light source increases the difficulty and cost of lithography equipment development, and its cost and large-scale capacity can no longer match the trend established in the past 25 years.

The threshold and cost of DUV / EUV lithography are very high, and the degree of freedom and customization ability are not strong [11]. Is it feasible to switch to other routes?

The cruel fact is that there are tens of millions of emerging lithography technologies, but most of them can not meet the needs of large-scale production, and no technology is omnipotent.

For the chip industry with a large market volume, as long as the advantages of technology can meet the demand, and the ideal lithography technology should have the characteristics of low cost, high throughput, small feature size, independent materials and substrates. [12]

At present, nanoimprint is the one closest to optical lithography.

Incomplete inventory of lithography technology and comparison of advantages and disadvantages, tabulation? fruit shell hard science and technology reference materials ("Applied Chemistry" [7] "Nano-imprint Technology" [13], Chinese Optical [12] Nano-imprint Lithography can not only produce high-resolution graphics below 5nm resolution. Also has a relatively simple process (compared with optical exposure complex system or electron beam exposure complex electromagnetic focusing system), higher production capacity (can be manufactured in a large area), lower cost (international authorities evaluate the same production level of nano-imprint at least one order of magnitude lower than traditional optical projection lithography) [14], lower power consumption [15], imprint template can be reused and other advantages.

Canon's research shows that with the throughput of 80 wafers per hour and the mask life of 80 wafers, nanoimprint lithography can reduce the cost by 28% compared with ArF lithography. As the throughput increases to 90 wafers per hour, the mask life exceeds 300 batches, and the cost can be reduced by 52%. In addition, by switching to a large-field mask to reduce the number of shots per wafer, the cost can be further reduced. [16]

Comparison between Nano-imprint Lithography and ArF Lithography [16] in 2020 and 2021, extreme Ultraviolet Lithography, guided self-Assembly (DSA) and Nano-imprint Lithography are listed as the main candidates for next-generation lithography in the International Devices and Systems Roadmap (IRDS) [17] [18]. The evaluation criteria include resolution, reliability, speed and alignment accuracy. In 2022, the importance of nano-imprint lithography in 3D NAND, DRAM and intersection storage was emphasized in IRDS. [19]

Process development route and potential technology [18] although nano-imprint lithography technology has been praised as the hope of the industry, it is not a perfect technology, and there are even many fatal problems, constantly delaying the time to enter the market.

2. The problem before being accepted by the industry it is not so easy to be the pioneer to break the rules.

Whether the nano-imprint technology can enter the industry finally depends on its production capacity and the minimum graphic feature size (Critical dimension,CD) that can be achieved. The former is determined by the pattern transfer area of the mold and the cycle time of a single imprint, while the latter is determined by the mold surface pattern CD and the accuracy of the positioning system. [2]

It should be pointed out that although nano-imprint lithography avoids the high price of projection lenses and the inherent physical limitations of optical systems in principle, from non-contact paradigm optical lithography to contact nano-imprint lithography, it has given rise to many new technical problems.

Technology branch line multi-nanometer imprinting technology has a history of only more than 20 years, but in such a short time, many branch routes have been born.

Nano-imprinting was invented in 1970, and it was not until 1995, when Stephen Y Chou of Princeton University put forward the thermal nano-imprinting technology for the first time, that the resolution of the imprint was as high as 10~50nm [20], which triggered a wide discussion in the industry. In the same year, he announced the patent US5772905A for this groundbreaking technology [21]. Since then, nanoimprinting has become an epoch-making fine processing technology, and new processes have emerged one after another.

A brief history of nano-imprint lithography [4] [13] [22-28], table-making, fruit shell hard technology has developed so far, the relatively mature and common nano-imprint processing methods include three types: thermal nano-imprint, UV nano-imprint and micro-contact printing (soft etching). Other new processes are mostly improved versions of these three processes. Among them, ultraviolet nano-imprinting has the most obvious advantages, which is the most common way of industrialization at present, while micro-contact nano-imprinting is mainly used in the field of biochemistry. [29]

Compared with different branch technologies, each has its own advantages and disadvantages, but with the current iterative situation of process nodes, in order to meet the increasingly fine requirements of microstructure manufacturing, it needs to be further improved and improved, and the multi-technology route is bound to make the road of industrialization more tortuous. [2]

The route of nano-imprint lithography classified by imprint method, mapping, fruit shell hard science and technology reference material, "nano-imprint technology" [22] although the process of nano-imprint lithography is a different way, but it can not get around the photoresist, coating, etching and other technologies, among which the photoresist is particularly difficult, and the photoresist in nano-imprint lithography is called nano-imprint glue.

The overall development of imprinting adhesive has experienced three stages from thermoplastic imprinting adhesive, thermosetting imprinting adhesive to ultraviolet imprinting adhesive, in which UV imprinting adhesive is the mainstream at present and in the future. From the perspective of patents, Fuji Film has a very strong technical reserve in the field of imprinting adhesive, while there are few patents in China. [30]

In addition, for nano-imprinting, the template is the key to the success of the device. Different from the 4X mask used in traditional optical lithography, the use of 1x template in nanoimprint lithography will lead to greater challenges in mold fabrication, inspection and repair technology. [2]

The key technology of nano-imprinting, tabulation, the reference material of fruit shell hard science and technology, "Research on the preparation of Micro-Nano structure based on Nano-imprint Technology" [31] is not so simple to use, although relative to optical lithography, nano-imprint lithography does simplify the principle, but there are more ways.

The traditional optical system is to form a photoresist film uniformly on the surface of the chip, while nano-imprinting requires targeted spraying of drop-shaped imprint glue [32]. This process is like printer inkjet, and it is not easy to control the strength.

In the process of imprinting, there will be air between the polymer pattern and the mask, just as bubbles are mixed in the process of mobile phone coating, nano-imprinting will also cause a situation that does not fit with the mask, once it enters the air, it will become a defective product and cannot work properly. As a result, in some cases, the embossed chips seem to be the same, but there are great individual differences at the nanometer scale. In order to solve the above problems, the method is completely opposite to that of optical lithography, that is, the chip is locally heated at the moment of imprinting, so that the mask can be tightly sewn in the process of nano-scale deformation [32]. However, the actual production process is more complex, with the exception of air, any fine dust will threaten the yield of the product.

Most nano-imprinting technologies require demoulding, and there is a strong adhesion between the template and the polymer, so the industry often evaporates a layer of nano-thickness anti-adhesion material on the template surface to facilitate easy demoulding. Just like putting a layer of oiled paper or brushing a layer of oil in the process of making a cake, the demoulding of the cake will be more smooth and complete. However, although this can solve the problem of demoulding, the cured polymer can not avoid physical friction with anti-adhesion materials and shorten the life of the template. [33]

In addition, although nano-imprinting technology has made great progress in mass production However, there are still challenges in template manufacturing, structural uniformity and resolution, defect rate control, template life, imprinting adhesive materials, complex structure preparation, pattern transfer defect control, resist selection and coating methods, mold material selection and manufacturing process, mold positioning and engraving accuracy, multi-layer structure height difference, precision control of imprinting process and so on. [2] [5]

It can be said that the development of nano-imprint lithography needs to abandon the past inherent experience and common sense and re-explore a set of methodology, which requires a lot of research and development and market trial and error.

3. Promising, but it will take time at this stage, many products are being produced using nano-imprint technology, including LED, OLED, AR devices, solar cells, sensors, biochips, nano-optical devices, nano-transistors, memory, microfluidic, anti-reflective coatings or films, ultra-hydrophobic surfaces, ultrafiltration films, etc. [14], but this technology has not yet entered the stage of large-scale production.

At present, Canon of Japan, EV Group of Austria, Molecular Imprints Inc of Texas of USA, Nanonex Corp of New Jersey of USA, Obducat AB of Sweden, SUSS MicroTec of Germany and other companies have produced nano-imprint lithography equipment, and some nano-imprint lithography equipment has supported 15nm. [1]

The nanoimprint market is not as big as expected, but the overall market is gradually strengthening. According to TechNavio data, the nanoimprint market is expected to reach US $3.3 billion in 2026 and a compound annual growth rate of 17.74% from 2021 to 2026. [34]

The potential of nano-imprint lithography has also been recognized by countries around the world, not only by Princeton University, University of Texas, Harvard University, University of Michigan, Lincoln Laboratory, Aachen University of Technology and other well-known universities and institutions, ASML (Asma), TSMC, Samsung, Motorola, Hewlett-Packard and other leaders also continue to be optimistic about the prospect of nano-imprint lithography, has been quietly increasing investment.

Global providers of nano-imprint lithography equipment do not have complete statistics, tabulation? fruit shell hard science and technology reference materials [33] although the domestic start is late, there are many players in the research and development of nano-imprint lithography, including scientific research institutions and companies. Including Fudan University, Peking University, Nanjing University, Jilin University, Xi'an Jiaotong University, Shanghai Jiaotong University, Suzhou University, Huazhong University of Science and Technology, Beijing Institute of Nano Energy and Systems, Chinese Academy of Sciences, Suzhou Institute of Nanotechnology and Nano Bionics, Shanghai Nanotechnology Research and Development Center, Suzhou Sodavig Technology Group Co., Ltd., Suzhou Lianyin Optoelectronics (Kunshan) Co., Ltd., Suzhou Optohelm Micro-Nano Technology Co., Ltd. [33]

For domestic, nanoimprint lithography will be a feasible way, perhaps we can see some trends in patents.

According to Smart Bud data, there are 1660 patents in 170 countries with both nanoimprint and lithography as keywords. From the point of view of the trend, 2007 to 2011 was the hottest year in the past 20 years, and then the patent application gradually slowed down. Correspondingly, at this time, the nano-imprint industry is in a period of expansion, and then entered a trough period, until the industry entered a mature period after 2020. [35]

According to the distribution of patent countries, the United States has 45.1% of the global nanoimprint lithography patents, with a total of 699. Although China ranks second, the total number of patents is less than 1/2 of that of the United States, accounting for 16.26% of the total global patents. Japan and South Korea ranked third and fourth in the number of patents, accounting for 13.35% and 10.13% of the total global patents, respectively.

From the point of view of the patent flow of China, the United States, Europe, Japan and South Korea, the distribution of nano-imprint lithography technology in the United States is distributed in the global market, while China's patented technology lacks a market outside China.

From the point of view of the company, the number of patents of molecular imprint lithography (Molecular Imprints Inc.) is far ahead, ranking first with 135patents. Canon (Canon Co., Ltd.) and Obodukat AG (Obducat AB) are not far behind, with 132and 49 patents respectively. In addition, applied materials, Samsung, Western Digital, Xinyue Chemical and other semiconductor leaders also have a strong patent layout.

According to the ranking map of applicants for nano-imprint lithography, it should be pointed out that although the total number of domestic patents is relatively large, the overall application is relatively scattered, while the international enterprises of the United States and Japan have a higher degree of concentration and a large number of patents of individual companies. Domestic laggards may face the risk of patent wall.

Judging from the current progress in the world, there will be news that nano-imprint lithography is about to break through every few years, but each time it is delayed to enter the industry. For domestic, we have to face not only the technical bottleneck of nano-imprint lithography, which is also difficult to solve internationally, but also the supporting technology, equipment and materials involved in nano-imprint lithography.

All the signals are telling about the difficulty of this technology, but in the future, when optical lithography is difficult to move forward, nanoimprint lithography will be the most anticipated route, and at that time, chip manufacturing may usher in a whole new paradigm and everything will be subverted.

References:

Nikkei News: Japan will counterattack with semiconductor "nano-imprint" technology. 2021.11.11. Https://cn.nikkei.com/ industry / itelectric-appliance / 46398-2021-11-11-05-03-00.html

Lan Hongbo, Ding Yucheng, Liu Hongzhong, et al. Research progress and development trend of nano-imprint lithography die manufacturing technology [J]. Journal of Mechanical Engineering, 2009, 45 (6): 1-13.

[3] World Science: research and Application of New Nano-imprint Lithography. 2012.8.9. Https://worldscience.cn/ c / 2012-08-09/582929.shtml

[4] Canon:Canon provides nanoimprint lithography manufacturing equipment to Toshiba Memory's Yokkaichi Operations plant.2017.7.20. https://global.canon/en/news/2017/20170720.html

Gao Xiaolei, Chen Yiqin, Zheng Mengjie, Duan Huigao. Large area nano-imprinting technology and its device application [J]. Optical Precision Engineering, 20220.30 (05): 555-573.

[6] Sreenivasan S V. Nanoimprint lithography steppers for volume fabrication of leading-edge semiconductor integrated circuits [J]. Microsystems & nanoengineering, 2017, 3 (1): 1-19.

[7] Hu Xiaohua, Xiong Shisheng. Advanced lithography technology: oriented self-assembly [J]. Applied Chemistry, 2021, 38 (9): 1029.

[8] Canon:NIL for the Semiconductor Market Tools that Advance Moore's Law. http://cnt.canon.com/products/

Liang Zixin, Zhao Yuanyuan, Duan Xuanming. Principle and technology of laser superdiffraction lithography [J]. Advances in Laser and Optoelectronics, 2022.

[10] Science net: pu Mingbo: the Frontier and Challenge of Optical Micro / Nano Machining Technology in Chip Manufacturing. 2022.9.7. Https://news.sciencenet.cn/ htmlnews / 2022/9/485866.shtm

Hu Yueqiang, Li Xin, Wang Xudong, et al. Research Progress of Micro-Nano Machining Technology for Optical superstructured surfaces [J]. Infrared and https://www.researching.cn/ Engineering, 2020, 49 (9): 202010Laser ArticlePdf / m00018/2020/49/9/20201035.pdf

[12] China Optics: Nanophotonics | Nanolithography: optical management and sensing applications of plasma nanoarrays. 2020.3.2. Https://mp.weixin.qq.com/ s/_vUHHMOK2cLzE8xPvJ9F4g

[13] Sun Hongwen. Nanoimprint technology [M]. Electronic Industry Press, 2011.

Zhang Di, Zhang Kui, Kong Luyao, Cheng Xiulan. Development and recent application of nano-imprinting technology [J]. Sensors and Microsystems, 2022, 41 (05): 1-5.

[15] Electronic Engineering album: in addition to EUV, there is also a lithography machine that seems to be very promising (part 1) .2022.12.14. Https://www.eet-china.com/ news / 202212148391.html

[16] Asano T, Sakai K, Yamamoto K, et al. The advantages of nanoimprint lithography for semiconductor device manufacturing[C] / / Photomask Japan 2019: XXVI Symposium on Photomask and Next-Generation Lithography Mask Technology. SPIE, 2019, 11178: 131140. http://cnt.canon.com/wp-content/uploads/2020/05/2019-05_The-advantages-of-nanoimprint-lithography-for-semiconductor-device-manufacturing.pdf

[17] IEEE:International Roadmap For Devices And Systems 2020 Edition Lithography. https://irds.ieee.org/images/files/pdf/2020/2020IRDS_Litho.pdf

[18] IEEE:International Roadmap For Devices And Systems 2021 Update Lithography. https://irds.ieee.org/images/files/pdf/2021/2021IRDS_Litho.pdf

[19] IEEE:International Roadmap For Devices And Systems 2022 Edition Lithography. https://irds.ieee.org/images/files/pdf/2022/2022IRDS_Litho.pdf

[20] Chou,Stephen Y Krauss physics letters,1995,67 Peter Ranson Renstrom [J] .Applied Krausz (21): 3114-3116.

[21] TechInsights:LITHOGRAPHY:Gatekeeper to Technological Independence and Advancement.2022

Zhou Weimin, Zhang Jing, Liu Yanbo, et al. Nanoimprint technology [M]. Science Press, 2012.

[23] Fujimori S. Fine pattern fabrication by the molded mask method (nanoimprint lithography) in the 1970s [J]. Japanese Journal of Applied Physics, 2009, 48 (6S): 06FH01.DOI: 10.1143/JJAP.48.06FH01

[24] PRNewswire-Asianet /-- Molecular Imprints developed J-FIL imprint lithography. Https://www.prnasia.com/ story / 83575-1.shtml

PR Newswire: Molecular Imprints' Semiconductor Business To Be Acquired By Canon.2014.2.13. https://www.prnewswire.com/ news-releases / molecular-imprints-semiconductor-business-to-be-acquired-by-canon-245428451.html

[26] Obducat:Obducat launch revolutionary technology enabling full industrialization of NIL.2020.9.18. https://www.obducat.com/cision/588AB155D46E8D8E/

[27] EV Group:EV Group and SCHOTT Partner to Demonstrate Readiness of 300-mm Nanoimprint Lithography for High-Volume Augmented/Mixed Reality Glass Manufacturing.2019.8.28. https://www.evgroup.com/company/news/detail/ev-group-and-schott-partner-to-demonstrate-readiness-of-300-mm-nanoimprint-lithography-for-high-volume-augmented-mixed-reality-glass-manufacturing-1566985083/

[28] EV Group:EV Group's new multi-functional micro / nano imprint solution gives unprecedented flexibility to mass optical equipment manufacturing. 2022.1.18. Https://www.evgroup.com/ zh / company / news / detail / new-multi-functional-micro-and-nanoimprint-solution-from-ev-group-offers-unprecedented-flexibility-for-high-volume-optical-device-manufacturing/

[29] Chen Fokui Study on preparation and performance of anti-reflection structure based on flexible nanoimprint convex window [D]. Guangxi University. 2022

Luo Lianyuan, Bian Xin, Li Mingrui, et al. Research and development trend of patent technology of nano-imprint adhesive [J]. Scientific observation, 2020, 15 (3): 12-28.

[31] Wang Mingyang. Study on the preparation of micro-nanostructures based on nano-imprint technology [D]. Harbin Institute of Technology, 2019.

[32] Canon: anecdote of Research and Development of New Generation Semiconductor Micro-processing Technology "Nano imprint". 2019.7.11. Https://club.canon.com.cn/ technology / technology-article-1082908846491435022.html

Zhou Xue, Bai Ling, Xing Yong, Dai Xiaonan. Nanoimprint technology and its development [J]. Information recording material, 2021, 22 (05): 32-35. Nano imprinting is not easy to process compound materials such as GaAs and InP.

[34] TechNavio:Nanopatterning Market by End-user, Product type and Geography-Forecast and Analysis 2022-2026.2022.12 https://www.technavio.com/report/nanopatterning-market-industry-analysis#:~:text=Methodology%20The%20nanopatterning%20market%20share%20is%20expected%20to,momentum%20will%20accelerate%20at%20a%20CAGR%20of%2017.74%25.

[35] Shenzhen Micro / Nano Manufacturing Industry Promotion Association: micro / Nano Manufacturing Technology / Patent industrialization Analysis report. 2021 Edition

This article comes from the official account of Wechat: fruit Shell hard Technology (ID:guokr233), author: Fu Bin

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