Advanced integrated circuit manufacturing is built around lithography
In the integrated circuit industry, there is a generation of devices, a generation of processes, a generation of equipment and materials, which means that after the entire industry enters the nano-era, micro-nano manufacturing technology relies more on introducing new materials and improving the processing capabilities of micro-processing equipment. To achieve technological breakthroughs, manufacturing processes and equipment materials are more deeply integrated. Many manufacturing processes often need to be built around key equipment materials. Photolithography machines are the most sophisticated, difficult, and expensive equipment in integrated circuit manufacturing.
A lithography machine expert told reporters: 'In the advanced integrated circuit manufacturing process, a chip often needs to go through dozens of lithography processes, each time using a lithography machine to make the circuit design graphics to the silicon chip Therefore, it is often said that the process node of a certain nanometer is often determined by the lithography machine and its related processes, or it is the core factor. How much resolution can be achieved by the lithography machine, integration How much is the process node of the circuit. '
Because the lithography machine is so important, about 30%-40% of the manufacturing companies invest in the lithography machine every year. The lithography machine has also undergone a long evolution: contact in the 1960s. Lithography, proximity lithography, projection lithography in the 1970s, step lithography in the 1980s, stepper lithography, immersion lithography, and The extreme ultraviolet (EUV) lithography machine on the market, equipment performance continues to improve.
At present, mainstream lithography products on integrated circuit production lines: for lithography of key layers of integrated circuits, 193nm wavelength dry lithography machine for nodes above 28nm, 193nm wavelength immersion lithography machine for 28nm-10nm nodes, for support 10nm integrated circuit manufacturing, the industry has begun to try to use EUV lithography machine, the next generation of high numerical aperture EUV lithography machine is currently under development, it is expected to be developed in the next 2-3 years, it can support 5nm, 3nm and The following process is manufactured. The non-critical layer uses a 248 nm wavelength DUV lithography machine and an I-Line lithography machine (365 nm wavelength).
Semiconductor expert Mo Dakang told reporters that the 10nm node and below process manufacturing is now more commonly used '193nm wavelength immersion lithography machine + Multiple exposure (MP) technology', can achieve 10nm and 7nm process production. However, multiple exposure There are two major problems. One is that the cost of lithography plus mask increases, and it affects the yield. One more process step is to reduce the yield once more. The second is that the cycle time of the process is extended, and multiple exposures not only increase the number of exposures, but also Increase the number of etching and CMP processes. EUV lithography machine does not require multiple exposures, and can expose the desired fine patterns at a time, which has obvious advantages in product production cycle, OPC complexity, process control, yield, etc. There are a number of EUV models on the market that have begun to ship. Samsung, TSMC have indicated that they will use EUV lithography machines in the 7nm process.
International lithography machine is highly monopolized
Although lithography machines are so important in the production of integrated circuits, the lithography industry is highly monopolized, and only 3-4 manufacturers worldwide can manufacture them. They are ASML in the Netherlands and Nikon in Japan. ), Canon and China's Shanghai Microelectronics (SMEE). Among them ASML is in a dominant position, a market with more than 70%, such as 193nm immersion lithography machine, ASML occupies more than 90% market share; 248nm DUV lithography machine ASML accounts for more than 50%; EUV lithography machine is only one of ASML's exclusive ones; I-Line lithography machine market is basically ASML, Canon, and Nikon are equally divided.
According to the data, the development of China's lithography machine is not too late. Since the 1970s, there have been Tsinghua University's Department of Precision Instruments, Institute of Optoelectronic Technology of the Chinese Academy of Sciences, and CLP of 45. The first time in 1978 After the production of the g-line step projection lithography machine in the United States, 45 companies have invested in the development of step-by-step projection lithography machine. In 1985, the first g-line 1.5μm step projection lithography machine of the same type in China was developed. In 1994, a step-by-step projection lithography machine with a resolution of 0.8μm was introduced. In 2000, a practical step-by-step projection lithography machine with a resolution of 0.5μm was introduced. In 2002, the state established Shanghai Microelectronics Equipment Co., Ltd. (SMEE) in Shanghai. Undertake the 'fifteen' lithography machine project, and the CLP Group's 45 teams engaged in the development of step-by-step projection lithography will be moved to Shanghai as a whole. Currently, Shanghai Microelectronics is the leading lithography in China. Machine development and production unit.
From the development progress, the task of '90nm lithography prototype development' in China has passed the field test of the expert group organized by the 02 special implementation management office. The 193nm wavelength immersion lithography machine of 28nm process node is under development. Some achievements, but China still lags far behind the international level in lithography technology.
Need to solve the dilemma of 'lack of people lacking money and lack of accumulation'
The requirement of ultra-high precision is one of the main reasons why the lithography machine technology is difficult to make breakthroughs in a short period of time. There is such an image metaphor in the industry: Using a lithography machine to engrave a circuit on a silicon wafer, like two The Boeing 747 is flying on a millet grain at a speed of 1000 kilometers per hour! This is the high-level lithography machine table, the nano-level synchronization accuracy achieved by the high-speed synchronous motion of the mask table. With such a high-precision chip, the accuracy requirements of the lithography machine itself are even higher.
In addition to technical challenges, experts told reporters that there are still many difficulties in developing lithography machines. In summary, it can be described as 'lack of lack of money and lack of accumulation'. First, the investment intensity of lithography machine development is very high. At the beginning Intel, TSMC, in order to promote ASML to accelerate the development of EUV lithography machine, it will acquire 23% of its shares at a price of 3.8 billion euros, and another 1.38 billion euros to support ASML's EUV technology research and development in the next five years. Over the years, China has attached importance to lithography. The development of the machine, the 02 special investment in the lithography machine, compared with the international manufacturers, there are too few. Second, there are a lot of blanks in the supporting basic industrial system developed by the domestic support lithography machine, which also limits the light. The development of the engraving machine. Finally, the talent base developed by the lithography machine is very small, the training is difficult, the training period is long, and the lithography machine has a long period of results and poor personnel treatment, which also causes a high level of brain drain. Intensified the backward state of domestic lithography machines.
In addition, Mo Dakang said that the development of the lithography machine is only a small part of the success. In order to form the corresponding lithography process, the mask factory has to develop a matching mask, the photoresist material of the material factory. The manufacturing plant combines equipment materials for process development, etc. This fully demonstrates the precision and systemicity of the lithography machine and related processes, and further increases the challenge of work.
Although China's lithography machine development faces many problems, with the rapid development of domestic mobile electronics, communications, automotive electronics, Internet of Things and other terminal application markets, it also provides a rare opportunity for the development of the domestic equipment industry. When the industry chain is short-boarded, experts pointed out: 'In the process of promoting the development of lithography machines, China should adhere to high-end active research and development, and realize the path of productization as soon as possible. The only way to support the entire R&D team, talent accumulation, engineering Experience accumulates and forms a virtuous circle. In addition, it should also attract the attention of the state to lithography machines, continue to increase investment in lithography machines, improve research and development conditions, attract talents, and pay attention to the sustainability of inputs while avoiding investment. The drawbacks of pulsed input.
Liu Bin, chief expert of China Electric Power, also pointed out: 'It is very important to establish long-term cooperation with downstream chip manufacturers. This has become a key link in the long-term development of China's semiconductor equipment industry and has not yet been finally resolved. 'As an upstream link in the semiconductor industry chain The development of the semiconductor equipment industry cannot be separated from the state's support. Due to the industry status of the equipment industry, equipment manufacturing units cannot have the same strength as the already established equipment suppliers in the world. Therefore, the development of the equipment industry requires huge research and development funds. Investment, professional technical team building and long-term cooperation with downstream chip manufacturers.