Chapter 187 Progress in Extreme Ultraviolet Light Sources
Optical Technology R&D Laboratory
The two leaders, Xu Hua and Li Mo, are discussing several issues regarding extreme ultraviolet light source technology.
"Dr. Li, although we have the blessing of a compound eye lens, debris contamination on the target is also a problem!"
Xu Hua felt a little worried.
Although the emergence of honeycomb compound eye lens technology has solved the core lens problem of extreme ultraviolet light sources to a certain extent, there are still some problems.
As we all know, the most critical component of the EUV extreme ultraviolet lithography machine is the extreme ultraviolet light source, which goes without saying.
There are five key technical issues that need to be overcome in the extreme ultraviolet light source before the light source can be officially manufactured.
One is a multi-layer film reflector. Since the EUV light source sub-energy is extremely high, it can be absorbed by almost all media. The higher reflectivity can greatly improve the performance of the light source.
After research, it was found that the reflector made of Mo/Si multilayer film has a central wavelength of 13.5nm and a spectral bandwidth of within 2%, and the reflectivity of EUV light can reach 70%.
This technology was conquered after Xu Li came up with the compound eye lens technology and after some experiments.
The second one is the target material. In order to reduce ion debris and improve EUV-CE, people began to gradually reduce the size of the Sn target, and finally used the droplet Sn target as the main research object.
However, the spatiotemporal instability of the droplet Sn also adds difficulty to the design and manufacture of the light source of the lithography machine.
The third and fourth ones are the driving light source and the double pulse mode, which will not be explained in detail here.
Finally, there is the problem of debris contamination. Laser plasma will be incident on the target material through the laser to generate high-temperature, high-density plasma and radiate EUV light. The process will inevitably produce a certain amount of debris (made of molten droplets, particle clusters,
Composed of neutral debris atoms and high-energy ions).
If these debris are not dealt with properly, they will also damage the optical components of the lithography machine, thereby affecting its performance and even having a certain impact on human health.
Currently, all commercially available EUV lithography products use a solution that combines filling with inert gas or hydrogen and applying an external magnetic field to remove debris. Of course, a double-pulse solution can also be used to remove debris.
However, both of these solutions are not suitable for the light sources currently designed.
Therefore, it is necessary to renegotiate and design a plan for removing debris.
"What's wrong? Look at your sad faces."
A familiar voice sounded in their ears.
The two turned their heads and saw that Xu Li was here.
He just came back from the construction site. Thinking of the recent research progress of the EUV light source project, he stopped by to take a look.
"Principal, we are discussing the key problem of two light sources..."
Li Mo explained, briefly going through the issues they discussed just now.
"Well, this is indeed a problem..."
Xu Li touched his chin.
"How about we do this..."
Xu Li put forward his own ideas.
First of all, since debris pollution is bound to occur, no matter which option is chosen, debris will inevitably be generated. Many methods for removing debris basically act as a buffer.
Then why not in turn absorb and transform it, which can not only greatly improve the utilization rate, but also greatly reduce the problem of debris pollution.
Then the target material can be replaced with tin. Although a lot of debris may be produced, as long as the absorption converter is made, this problem can basically be solved, and it will not increase the difficulty of designing the light source.
"Wonderful! Principal, your idea may be more feasible!"
Xu Hua's eyes lit up.
"This can be regarded as a clever method. It can be used to re-research new target materials in the short term, which also saves a lot of time."
Li Mo also thinks this idea is good.
"In this case, let's try it quickly, but I don't know much about some key technologies of extreme ultraviolet light sources, so I can only help you later."
Xu Li smiled.
Although he obtained several technologies from the Science and Technology Library, his in-depth understanding of extreme ultraviolet light sources is definitely not as deep as the two in front of him.
I can only be a helper during the experiment, and it’s good to learn something along the way.
"Principal, you must be humble. If you didn't understand, the honeycomb compound eye lens wouldn't appear."
"It's okay even if you don't understand. I believe the principal can do it too."
Xu Hua and Li Mo also laughed, thinking that Xu Li was showing modesty.
"Okay, let's stop talking nonsense. Let's quickly prepare experiments to see if our plan is feasible. Let's get the debris suction and transfer device out first."
Xu Li interrupted them.
"Okay!"
As a result, the three of them began to engage in intense and busy experiments and research.
Xu Li also learned a lot during this process.
For example, the rigorous experimental thinking and attitude of these two researchers, as well as their various operations, as well as some basic knowledge in the semiconductor field that he is not very clear about.
These have benefited him a lot.
Confucius said: "When three people are walking together, they must have me as their teacher."
Even though Xu Li has a plug-in, he is not a proud and indulgent person.
Above the earth, in the deep space universe, there are countless beings who are stronger than him and have profound knowledge.
Therefore, learning from these elders can also promote your own progress.
During this period, Xu Li also called his mother in advance to tell him that he would not be back tonight and would participate in the experimental work.
But Xu Hua went to rest first, because he was over fifty and couldn't stand it.
Only Xu Li, Li Mo and a few young assistants were left in the laboratory, and the others asked them to go back and rest.
Seeing that the eyes of several assistant researchers were red, Xu Li asked them to go to the temporary lounge next door to take a nap.
Several people did not refuse. After all, it was three o'clock in the morning and they really couldn't stand it any longer.
"Dr. Li, why don't you go take a nap first and I'll do the rest."
Xu Li opened his mouth and said.
"But principal, you..."
Li Mo hesitated. He was indeed very sleepy now, but the experiment had not been completed yet, and it was unreasonable to let his boss stay here alone.
"It's okay. I'm okay. You should go and rest first. Your health is important. Staying up late is not good for your health. If I succeed, I will notify you as soon as possible."
"Okay."
Seeing Xu Li's persistence, Li Mo no longer objected and turned around and left the laboratory.
Seeing everyone leaving, Xu Li called out.
"Xiao Hei!"
"Principal, I'm here! What are your orders?"
Xiaohei's cat face suddenly popped up from the computer next to him.
"Help me calculate and analyze..."
Now to design the suction rotor, it is inevitable to carry out analysis and calculation.
It was relatively slow for Xu Li to calculate and build the data model by himself, so he asked Xiao Hei to help.
The computing and analysis capabilities of artificial intelligence are definitely faster.
And he couldn't expose Xiao Hei to others for the time being, so he sent others away.
In this way, he can use Xiao Hei's power to accelerate the research progress of extreme ultraviolet light sources.