Exposure of a new generation of EUV lithography machine: the size of a bus and the cost of nearly 1 billion

Recently, ASML has reported that a new generation of extreme ultraviolet lithography (EUV) has been developed and the final part of the installation is currently in progress. According to people familiar with the matter, the cost of this new EUV equipment will be as high as 150 million U.S. dollars (approximately 970 million yuan).

The size of the bus is expensive, and the configuration is sky-defying

This latest lithography machine is located in a large clean room in the suburbs of Connecticut, USA. Engineers are carrying out the final work to carve a huge piece of aluminum into a frame, and finally let the photomask in it with nanometer precision. Move, reflect the extreme ultraviolet beam. These beams are reflected back and forth by several mirrors, repeatedly modified and polished with amazing precision, and feature patterns of only a few dozen atoms in size are etched on the silicon wafer.

Such an extreme ultraviolet lithography machine is expected to allow the chip manufacturing industry to follow Moore’s Law for at least another 10 years.

It is worth noting that this new generation of extreme ultraviolet lithography machine is about the size of a public bus, and the cost is as high as 150 million US dollars. The entire machine contains 100,000 parts and 2 kilometers of cables. Even more exaggerated is that for such an extreme ultraviolet lithography machine to be shipped, at least 40 containers, 3 cargo planes or 20 trucks are required.

Jesús del Alamo, a professor at MIT who studies new transistor architectures, believes that this is an incredible machine: “This is definitely a revolutionary product, a breakthrough that will bring new life to the chip industry.”

It is reported that the manufactured components will be shipped to the Netherlands at the end of 2021, and then installed in the first prototype of a new generation of extreme ultraviolet lithography machine in early 2022. The new generation of extreme ultraviolet lithography machines use larger numerical apertures to further reduce the size of the components on the chip. This method allows light to pass through the mask at different angles, thereby increasing the resolution of pattern imaging. This requires larger mirrors and new hardware and software to precisely control component etching.

ASML’s current generation of extreme ultraviolet lithography machines can produce chips with a resolution of 13nm. The new generation of extreme ultraviolet lithography machines will use higher numerical apertures to produce 8nm-sized feature patterns. Not surprisingly, the new generation of extreme ultraviolet lithography machines will etch patterns smaller than any previous machine, allowing each chip to have tens of billions of components. The chips produced by this machine in the next few years should be The fastest and most efficient in history. In short, ASM’s new generation of extreme ultraviolet lithography machine is expected to continue the concept of continuous progress in chip manufacturing and the entire technology industry, and continue to keep Moore’s Law alive.

It is worth noting that ASML launched the world’s first mass-produced extreme ultraviolet lithography machine as early as 2017. It plays a vital role in the field of chip manufacturing and has been used to manufacture iPhone chips and artificial intelligence. The most advanced chips such as processors. The latest generation of extreme ultraviolet lithography equipment has undergone several generations of replacement, and only a few companies such as TSMC, Samsung and Intel can afford such equipment in the world.

The importance of lithography machine in chip production

Regardless of the small size of the chip, there is actually infinite “energy” inside. The manufacturing process of the chip is extremely complicated, and it is necessary to continuously accumulate patterns on the wafer. These patterns are connected longitudinally, up to 100 layers.

The manufacture of a chip involves hundreds of steps, and it may take four months from design to mass production. In the clean room of the fab, precious wafers are continuously transported through mechanical equipment, and the air quality and temperature are strictly controlled throughout the process. From the point of view of the key process of chip manufacturing, it is divided into the following 10 major steps.

1) Deposition: The first step in chip manufacturing is usually to deposit a thin film of material on the wafer. The material can be a conductor, an insulator or a semiconductor;

2) Photoresist coating: Before photolithography, the photosensitive material “photoresist” or “photoresist” should be coated on the wafer first, and then the wafer should be placed in the photolithography machine;

3) Exposure: Make the blueprint of the pattern that needs to be printed on the mask. After the wafer is placed in the lithography machine, the light beam is projected onto the wafer through the reticle. The optical elements in the lithography machine shrink and focus the pattern onto the photoresist coating. Under the irradiation of the light beam, the photoresist undergoes a chemical reaction, and the pattern on the photomask is thus imprinted on the photoresist coating;

4) Computational lithography: The physical and chemical effects generated during lithography may cause pattern deformation, so it is necessary to adjust the pattern on the reticle in advance to ensure the accuracy of the final lithography pattern. ASML integrates existing lithography data and wafer test data to make algorithm models and precisely adjust patterns;

5) Baking and development: After the wafer leaves the photoetching machine, it must be baked and developed to make the photoetched pattern permanently fixed. Wash off the excess photoresist, leaving a blank part of the coating;

6) Etching: After the development is completed, use gas and other materials to remove the excess blank parts to form a 3D circuit pattern;

7) Measurement and inspection: During the chip production process, the wafers are always measured and inspected to ensure that there are no errors. The detection results are fed back to the lithography system to further optimize and adjust the equipment;

8) Ion implantation: Before removing the remaining photoresist, the wafer can be bombarded with positive or negative ions to adjust the semiconductor characteristics of some patterns;

9) Re-copying process steps are required: from film deposition to removal of photoresist, the whole process is to cover the wafer with a layer of pattern. To form integrated circuits on wafers and complete chip production, this process needs to be repeated continuously, up to 100 times;

10) Package the chip: The last step is to cut the wafer to obtain a single chip, which is packaged in a protective case. In this way, the finished chip can be used to produce TVs, tablets or other digital devices.

As mentioned above, “re-copy process steps as needed”, the structure of modern chips can be as many as 100 layers, which need to be superimposed on each other with nanometer-level precision. This precision is also called “overlay precision.” The size of each layer pattern of lithography on the chip is different, which means that different equipment is required for lithography of each layer pattern. ASML’s DUV deep ultraviolet lithography machine has several different models, which are suitable for the critical lithography requirements of the smallest patterns and the normal lithography of ordinary patterns.

Nowadays, the structure of the chip can be as many as 100 layers, which need to be superimposed on each other with nanometer precision. This precision is also called “overlay precision.” The size of each layer pattern of lithography on the chip is different, which means that different equipment is required for lithography of each layer pattern. ASML’s lithography machine has several different models, which are suitable for the key lithography requirements of various patterns and the normal lithography of common patterns.

Intel early adopters? The first batch of chips offline in 2023

As we all know, the lithography machine equipment is extremely complicated. Only ASML can produce high-end lithography machines in the world, and the production capacity is extremely limited. Before the emergence of a new generation of extreme ultraviolet lithography equipment, TSMC almost took over 70% of ASML’s production capacity. Even Samsung did not have enough equipment to expand the production capacity of 5nm high-precision chips. This is the main reason why TSMC has been leading Samsung.

The new generation of extreme ultraviolet lithography equipment is reported to be adopted by Intel first. Intel said it expects to roll off the first batch of chips in 2023. With the pattern size etched by any machine smaller than before, so that each chip has tens of billions of components, the chips produced by this machine in the next few years should be the fastest and most efficient in history.

All in all, from the perspective of the development of the entire semiconductor industry technology, the emergence of a new generation of extreme ultraviolet lithography equipment has epoch-making significance, but for the domestic chip industry that is still in the climbing stage, due to restrictions on high-end advanced technology, etc. The reason is that the gap with leading companies in cutting-edge technology may be further widened.

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