As an indispensable part of the chip process, lithography plays a key role in transferring the circuit pattern to the silicon wafer. As chip sizes continue to shrink and circuit complexity increases, lithography processes become more complex and sophisticated. With nearly 200 million transistors per square millimeter of chip area in the 3nm process, the resolution of the visible lithography process is crucial. To meet this challenge, there are a variety of lithography machines on the market, such as i-line, g-line, KRF, ARF, ARFI, and EUV lithography machines. Among them, the immersion lithography machine, also known as the ARFI lithography machine, is currently the most widely used lithography machine. Compared to the ARF lithography machine, the ARFI lithography machine uses the same 193nm light source, but adds a layer of water as a medium in front of the silicon wafer. The light is refracted by water with an equivalent wavelength of 134 nm, which improves the resolution. Therefore, ARFI lithography machines can theoretically support up to 7nm processes.
However, in fact, many people do not realize that 7nm is not the limit for immersion lithography machines. As long as they are not limited by cost, immersion lithography machines can even achieve processes of 3nm, 2nm and even smaller. This involves the issue of multiplexing and alignment. Taking a chip as an example, the original circuit pattern is designed with 10 layers, and we can split it into 30 layers, 40 layers, or even more, through multiple lithography processes, and finally achieve higher resolution. However, in each process, the precision of alignment is crucial. As you can imagine, just like we rub on a smaller piece of paper, if it's not feasible to rub the entire complex pattern at once, we need to rub it in multiple times. to rub one"Wang"For example, let's first rub a horizontal line"one"then slowly move the paper position to rub a horizontal line again"one", followed by rubbing a vertical line"|", and finally rub a horizontal line to form"Wang"Word. In this process, the paper position must be accurately moved after each rubbing to ensure that the error is controllable each time. The principle of multi-chip is similar, only the error of each time is small enough, we can actually use multiple lithography to make a small chip onto a silicon wafer.
However, the cost of this method is very high. Since the work that used to be completed in one lithography now needs to be divided into multiple times, for example, from one time to 10 or even 20 lithography, the time required has increased by 20 times, and the cost has increased by 20 times. Moreover, considering that the yield of the chip will decrease every time it is ** more, the cost is actually 20 times higher. Chip manufacturing is commercial, and the cost factor needs to be considered, and if the cost is too high, it cannot be practically applied. Therefore, generally speaking, immersion lithography machines can only support the manufacture of 7nm chips at most, and then cannot be advanced because the cost is too high to be commercialized. However, this does not mean that 7nm is the limit of immersion lithography machines. Theoretically, there is no such thing as a limit, as long as the cost is high enough, we can continue to push the boundaries of technology.
As one of the most advanced lithography technologies, immersion lithography has great potential and prospects. However, there are still many challenges to applying it to real-world chip manufacturing.
First of all, the cost of immersion lithography machines is still very high. Due to the multiplexing and complexity of the alignment process, the time cost and equipment investment per lithography is relatively high. This puts significant cost pressure on the commercial application of immersion lithography machines. How to reduce production costs while ensuring high quality will be the focus of future development.
Secondly, the technological breakthrough and innovation of the immersion lithography machine is also the key to progress. In order to achieve higher resolution and more complex circuit patterns, it is necessary to continuously improve the lithography light source and optical system, improve the performance of the wetting medium, optimize the alignment algorithm, etc. Only through technological innovation and breakthroughs can the performance and manufacturing capacity of immersion lithography machines be continuously improved.
Finally, the reliability and stability of immersion lithography machines are also one of the factors restricting their development. In actual production, equipment needs to be able to operate stably for long periods of time and maintain consistent performance in the face of various environmental and process changes. Therefore, it is very important to improve the reliability and stability of immersion lithography machines.
However, despite the challenges, immersion lithography machines still hold great promise. With the continuous advancement of chip technology and the market demand for higher performance chips, the demand for higher resolution lithography technology is also increasing. As one of the most promising options at present, immersion lithography will play an important role in the field of chip manufacturing. As long as the technical barriers can be broken, the production cost can be reduced, and the reliability and performance stability of the equipment can be improved, the position of the immersion lithography machine in the chip process will be more important in the future.
As one of the most advanced lithography technologies, immersion lithography has great potential and prospects. Although there are still many challenges in commercial applications, with the development of science and technology and the promotion of innovation, it is believed that these problems can be solved in the end. As a self-editor, I am confident in the development and application of immersion lithography machines.
In the face of technological boundary challenges, we should maintain a positive attitude and encourage technological innovation and breakthroughs. Only by constantly seeking new solutions can we overcome the bottlenecks of technology and achieve higher performance and smaller size. At the same time, we also need to pay attention to cost control and reduction to ensure that the immersion lithography machine can be actually used in commercial production.
For immersion lithography machines, technological breakthroughs and innovations will be key to driving their development. As an editor, I will continue to follow and report on the latest advances in lithography technology to provide accurate and detailed information to readers. I believe that immersion lithography machines will play an increasingly important role in chip processes in the future, bringing us more advanced and powerful chip products. Let's look forward to the vigorous development of lithography technology and the future of science and technology.