At present, the advanced lithography machine that has been put into mass production in China is the 90nm lithography machine. Although the 28nm lithography machine has achieved a technological breakthrough, it is still in the testing stage. Because the yield is relatively low, it has not been put into mass production.

First of all, we can definitely tell you the answer. It's impossible 

Some friends may say that it is no problem to use a 90 nm lithography machine to produce a 14 nm chip after process improvement and multiple exposures, but this is only an ideal value in theory and is not feasible in reality.

First of all, let's popularize a basic common sense, that is, the wavelength and accuracy of a lithography machine are two different things.

When it comes to photolithography, the process we normally speak of generally refers to its precision, that is, resolution. For example, the domestic 90nm photolithography machine is also 90nm resolution.

But in fact, the wavelength of 90 nm precision lithography machine is not 90 nm, but much larger than 90 nm.

At present, there are two types of lithography machines on the market, one is EUV lithography machine, and the other is DUV lithography machine. Only ASML in the Netherlands has mastered the technology of EUV lithography machine, and other countries have not.

At present, the domestic lithography machine belongs to DUV lithography machine. The light source of DUV lithography machine is excimer laser. According to different technologies, the wavelength of DUV lithography machine can be divided into 365 nm, 248 nm, 193 nm and equivalent 134 nm.

At present, the wavelength of domestic 90nm DUV lithography machine should be between 193 nm and 248 nm.

Then why do we say that the domestic lithography machine is advanced to 90 nm? In fact, in addition to wavelength, objective lens and light source are also required to improve the accuracy.

However, at present, domestic objective lenses and light sources also face great challenges. The world's top objective lens and light source manufacturers, such as Zeiss in Germany and Crymer in the United States, cannot export advanced objective lenses and light sources to us. It is difficult to improve the precision of lithography machines in a short period of time only if domestic suppliers provide them.

Therefore, it is almost impossible to use a domestic lithography machine to make 14 nanometer chips. If it were possible, we would not have such a headache now.

Some friends may say that a 14nm chip can also be produced with a 90nm lithography machine after multiple exposures, but many people may have overlooked several problems.

The first is cost 

If we use a 90 nm lithography machine to produce 14 nm chips through multiple exposures, the cost will rise rapidly, which may be several times the cost of ordinary 14 nm chips. The chips finally produced will have no market advantage, and the enterprise will not be able to do such a loss making business.

The second is the yield rate 

Even though our country can really produce 14nm chips with 90nm lithography machine after many efforts, the yield rate will not be very high. It is very good that the yield rate can reach 10%. Such a low yield rate not only greatly increases the cost of enterprises, but the key is whether any manufacturer is willing to purchase such chips.

Therefore, after integrating various factors, it is basically impossible to use 90 nm domestic lithography machine to manufacture and implement nano chips.

At present, the only hope is that after the mass production of domestic 28nm lithography machine, it is indeed possible to produce chips of 14nm or even 7nm.

At present, the domestic 28nm lithography machine has achieved technological breakthrough and is still in the testing stage. According to the original plan of Shanghai Microelectronics, it is said that it will be mass produced by the end of 2022, but according to the current progress, it is estimated that it is difficult to achieve mass production in the short term, and it may need to wait until 2023 or even 2024.

However, since China has achieved a breakthrough in 28nm lithography technology, the mass production of 28nm lithography will come sooner or later.

Once China has mastered the mature 28nm lithography machine, it can be used to produce 14nm lithography machine, or even 7nm nano chip, with the improvement of chip manufacturing process, after multiple exposures.

We should know that the first generation 7nm chip of TSMC was also realized by DUV lithography machine. At that time, they used the ARFi model DUV lithography machine of ASML, which had a large resolution of 38nm.

It is said that the new generation lithography machine developed by Shanghai Microelectronics also has a high resolution of 38 nanometers, so there is really great hope that it can be used to produce 14 nanometer chips and 7 nanometer chips.

Of course, in addition to relying on the technological progress of the lithography machine, there is still a way to improve the chip performance in the market at present, that is, chip stacking, that is, to stack two chips together, so as to achieve the purpose of improving the chip performance. This way has been proved to be feasible.