The battle for EUV lithography equipment has begun

Source: Content from China Electronics News , thank you.

Recently, ASML, a Dutch lithography machine manufacturer, released its 2020 annual financial report, with full-year net sales reaching 14 billion euros and a gross profit margin of 48.6%. ASML also announced the shipment of the 100th extreme ultraviolet lithography (EUV) system. By the end of 2020, 26 million wafers had been lithographed using the EUV system. With the development of semiconductor technology, the accuracy of lithography continues to improve. In 2021, advanced processes will enter the 5nm/3nm node. Extreme ultraviolet lithography has become a compulsory course, and EUV has also become the focus of competition for procurement by leading semiconductor manufacturers. In the future, how will extreme ultraviolet lithography technology develop? How will the industrial landscape evolve? How should my country solve the problem of lithography technology in developing the semiconductor industry?

At a time when Moore's Law continues to challenge the limits of physics, the competitive situation in the field of advanced semiconductor processes can be described as "whoever gets EUV gets advanced processes." TSMC, Samsung Electronics and other manufacturers have accelerated the process of introducing EUV. For this reason, EUV is becoming the focus of semiconductor giants' competition for an advantageous position in the field of advanced processes.

Recently, there have been frequent reports of high-level visits between Samsung Electronics and ASML. In October 2020, Samsung Electronics Vice Chairman Lee Jae-yong visited ASML and held talks with ASML CEO Peter Wennink and CTO Martin van den Brink. At the end of 2020, there was news that Peter Wennink returned to visit Samsung Electronics.

Some industry insiders pointed out that the core of such frequent mutual visits is of course EUV equipment. Samsung Electronics hopes that ASML will provide more EUV equipment, and at the same time hopes that ASML will assist Samsung Electronics in using the EUV it has already purchased more smoothly. It is understood that ASML's EUV production capacity in 2021 is about 45 to 50 units. TSMC grabbed 30 of them, and the rest were divided up by competitors such as Samsung, Intel and SK Hynix. In this way, Samsung Electronics is bound to lose to TSMC in the number of EUV equipment in 2021. Samsung Electronics previously proposed the "Semiconductor Vision 2030 Plan", which plans to surpass TSMC in the field of wafer foundry in 2030. This is the main reason why Samsung executives personally visited ASML.

In fact, after semiconductor logic process technology enters the 7-nanometer generation and below, EUV is required as the exposure medium due to the excessively fine line width. Currently, only TSMC, Samsung and Intel are left in the world with the ability and willingness to enter the 7-nanometer generation. In addition, the supply of EUV equipment is limited, so ASML has become an important target that the three major semiconductor giants are vying to win over.

With the development of semiconductor technology, the accuracy of photolithography has been continuously improved, from micron level, submicron level, deep submicron level to the current nanometer level, and the wavelength of the exposure light source has also evolved from 436 nanometers (G line), 365 nanometers (I line), to 248 nanometers (KrF), 193 nanometers (ArF), and then to 13.5 nanometers (EUV).

EUV is the key to breaking through the 10-nanometer line width, and even the subsequent 7-nanometer, 5-nanometer, and 3-nanometer processes. Huachuang Securities' research report shows that the difficulty and key point of semiconductor chip production lies in transferring the circuit diagram from the mask to the silicon wafer, a process that needs to be achieved through lithography. The process level of lithography directly determines the process level and performance level of the chip. Chips need to undergo 20 to 30 lithography processes in production, which takes up about 50% of the IC production process and 1/3 of the chip production cost. If EUV is used, the fab can reduce the optical troubles encountered in shrinking the chip design, and in the process, some multi-patterning steps can be eliminated, which can save costs and time and improve the yield rate in ideal cases. It is for this reason that despite the high price of ASML's EUV of US$120 million, manufacturers such as Samsung and TSMC are still actively purchasing it.

TSMC announced at a recent earnings conference that capital expenditures for equipment purchases in 2021 will be approximately US$25 billion to US$28 billion, an increase of 45% to 62% from US$17.2 billion in 2020. TSMC Chief Financial Officer Huang Renzhao said that in order to cope with the development of advanced and special process technologies and to meet the growth of customer demand, the company will increase capital expenditures in 2021, of which 80% will be used for advanced processes such as 3nm, 5nm and 7nm.

Data shows that TSMC's 5nm node can improve performance by 15% (at the same power and complexity), reduce power consumption by 30% (at the same frequency and complexity), and increase transistor density by up to 1.8 times (not applicable to all structures) compared to the 7nm node. In addition, the 5nm node will use EUV on devices with more than ten layers, which allows TSMC to reduce the number of masks used and the number of times multiple pattern exposures are used.

In the future, advanced processes will continue to advance to 3nm, 2nm, and even 1nm. By then, EUV will play a greater role. Luc Van den hove, CEO and president of semiconductor research institute imec, pointed out that imec will continue to play a role in Moore's Law by working closely with ASML to develop and implement a new generation of high-resolution EUV lithography technology (high NA EUV Lithography). Even after the process miniaturization reaches 1nm, Moore's Law will continue to apply.

Not only does the logic chip manufacturing process require the use of EUV equipment, but in the future, large memory chip manufacturers such as Micron and SK Hynix will also use EUV equipment when mass-producing DRAM. Semiconductor expert Mo Dakang pointed out that there are two main types of memory: one is DRAM and the other is 3D NAND. The current competition in 3D NAND is mainly focused on the number of layers. Although it also requires miniaturization of line width, the demand is not so urgent. DRAM memory is different. If it is achieved below 1z (12-14nm), EUV lithography machines may be needed. By then, the EUV equipment ordered by memory manufacturers will have a big explosion.

It is reported that Samsung Electronics has tried to apply EUV to the production of 1z DRAM. In August 2020, Samsung Electronics announced that the second new production line at its Pyeongtaek plant began to produce 16Gbit LPDDR5 mobile DRAM. Samsung Electronics shipped 1 million fourth-generation 10nm DRAM wafers produced using EUV.

In the memory industry, the current generational divisions are 1x, 1y, 1z, 1α, and 1β. SK Hynix said it is preparing for mass production of DRAM using EUV. SK Hynix plans to apply EUV to 1α DRAM from 2021 and 1β DRAM in 2022. SK Hynix plans to upgrade the equipment of the M14 wafer fab and install an EUV lithography system in the new wafer fab, the M16 wafer fab, which is about to be put into use.

Micron is also planning to use EUV. It is reported that Micron is looking for engineers to manage EUV equipment. Raj Taluri, senior vice president and general manager of the mobile products division of Micron Technology, believes that the key consideration of whether to adopt EUV lies in the cost and efficiency of chip production. "The multiple patterning exposure technology we are using now has more obvious advantages in cost and efficiency than the use of EUV. Now that we have advanced to the 1α node, we think that the existing multiple patterning exposure technology will have more cost advantages when it comes to the 1β and 1γ nodes. But after 1γ, we may try to use EUV. We will conduct a cost-efficiency analysis, and if it proves to be more cost-effective, we will consider adopting it. Of course, we will invest funds in the exploration and development of related processes in the early stage."

In addition to ASML, other lithography machine suppliers include Japanese manufacturers Nikon and Canon. As EUV becomes more and more important, ASML's advantages are becoming more and more obvious. Canon and Nikon can only compete with it in "deep ultraviolet" (DUV) lithography systems. But even in the DUV field, ASML has a 62% market share.

However, the extreme ultraviolet lithography industry is not just about EUV lithography machines. According to semiconductor expert Mo Dakang, EUV also includes peripheral equipment such as photomask defect detection and coating development, as well as key materials such as photoresist. Photomask defect detection equipment can detect defects in the photomask. If the photomask carrying the original circuit has defects, the defect rate of the chip will increase accordingly. Therefore, this equipment is also very important. Japan's Lasertec is a major manufacturer in this field. Yutaro Misawa, director of Lasertec's business planning office, pointed out: "With the development of miniaturization, the sensitivity of DUV may not be sufficient when entering the 2-nanometer process." The demand for detection equipment using EUV light sources is expected to grow further.

EUV coating and developing equipment is used to apply special chemical liquids on silicon wafers for developing semiconductor materials. As the input (photoresist coating before exposure) and output (development of patterns after exposure) of the lithography machine, the performance of the coating/developing machine directly affects the formation of fine exposure patterns, and the pattern quality and defect control of its development process also have a profound impact on the pattern transfer results of many subsequent processes (such as etching, ion implantation, etc.). Tokyo Electron is a major supplier in this field. Tokyo Electron's President Toshiki Kawai pointed out that if the introduction of EUV can promote technological progress in the entire process, the number of processes that are not directly related to EUV will also increase. Domestic equipment manufacturer Xinyuan Micro recently stated that the company's front-end coating and developing machine has overcome the technical problems of connecting with international lithography machines and has been verified, and can be connected with lithography machines of international brands including ASML, Canon, and Shanghai Microelectronics (SMEE).

Photoresist has extremely high requirements for resolution, contrast, sensitivity, viscosity, adhesion, etc. At present, the major photoresist companies in the world include Japan Synthetic Rubber (JSR), Tokyo Ohka (TOK), Sumitomo Chemical, Shin-Etsu Chemical, and Rohm and Haas of the United States, which account for more than 85% of the market share, and the market concentration is very high. At present, China can already mass-produce three types of photoresists: G-line, I-line, and KrF. Nanjing University of Science and Technology Optoelectronics plans to achieve an annual production scale of 25 tons of 193nm (ArF dry and immersion) photoresist products through three years of construction, production and sales, and will tackle EUV photoresist in the future.

Lithography is an inevitable topic for the development of my country's semiconductor industry. Given the current weak domestic foundation, it is not realistic to conquer EUV equipment in the short term. In this regard, Mo Dakang pointed out that high-performance lithography technology is costly for Chinese companies, but its strategic significance cannot be ignored. China can only adopt a low-to-high strategy to promote the development of a complete lithography industrial system, such as 193nm deep ultraviolet ArF dry lithography machines, immersion lithography machines, and peripheral equipment and materials. EUV is the most difficult part of the entire system.

"To achieve powerful functions, EUV must overcome the influence of factors such as power consumption and light source." Liu Bin, chief expert of the 45th Institute of China Electronics Technology Group Corporation, said that although the price of EUV exceeds 100 million US dollars, the high price is not its biggest problem. The biggest problem of EUV is power consumption. Its power consumption is 10 times that of traditional 193nm lithography machines, because the wavelength of extreme ultraviolet light is only 13.5nm, and the intensity of exposure projected onto the wafer surface is only 2% of the light before entering the optical path system of the EUV equipment. In comparison with the cost of 7nm, the power consumption cost of 7nm EUV production efficiency at 80 pieces/hour will be twice the power consumption cost of 14nm traditional lithography production efficiency at 240 pieces/hour, not counting the equipment purchase cost and mask design and manufacturing cost.

In addition to power and light sources, photoresist is another problem that EUV technology needs to face. According to experts, photoresist itself is very sensitive to light, but the sensitivity of photoresist to light sources of different wavelengths is also different, which creates some requirements for EUV lithography machines. The wavelength selected by the lithography machine must be in the same band as the wavelength corresponding to the photoresist, so as to improve the absorption rate of the photoresist to the light source, thereby better realizing chemical changes.

Mo Dakang said that although extreme ultraviolet lithography is leading, there is still a lot of room for improvement. Therefore, it is an effective strategy for domestic manufacturers to gain a foothold in DUV and other fields first, start from peripheral equipment and materials, gradually solve the problems in the industry, and make the industry solid.