"In general, the positioning resolution of the lithography machine will be one to two generations higher than the process resolution. ”

"Our current chip manufacturing process is 0.35 micron technology, and the positioning resolution can reach the 0.25 micron level. ”

"According to the normal R&D sequence, we will develop positioning resolution technologies in the 0.18 and 0.13 micron levels over the next five years. ”

"Limited by our current state of the art, by 2004 we will be able to push the positioning resolution up to 90 nanometers. ”

Seeing Lin Qianjun away, Wang Zhongjun showed a sad face in the closed meeting in the laboratory.

After everyone has finished fighting, enthusiasm cannot be directly turned into scientific research results, and science and technology are never transferred by human will.

So when it comes to specific issues, it's time to lose your hair or your hair.

"This is the case, we are now able to achieve 0.25 microns in order to catch up with the international advanced level, after paying great pressure to achieve the results. ”

"But to meet the needs of the authorities, our nanogratings have to reach a resolution of 100 nanometers. This is no longer a sub-micron technology, but a micro-nano category. In other words, we need to leapfrog at least five years of technological development to advance the positioning resolution to 100 nanometers. ”

Wang Zhongjun couldn't help frowning when he said this, and touched the cigarette case with his hand but didn't open it: "Let's talk about it, do you have any ideas?"

The researchers in the lab below looked at each other and made a mistake together.

"How about continuing to use chemical etching......?

"No, the anisotropy of chemical etching is too poor. Even repeated exposure etching will lead to erosion on both sides, and the accuracy will inevitably not meet the requirements of 100 nanometers. ”

The manufacturing technology of nano grating is actually similar to that of making chips, which is by coating photoresist on silicon wafers, and then repeatedly exposing and etching, and finally forming a grating that meets the accuracy requirements. However, the chemical etching method commonly used in the industry is not suitable for micro and nano conditions.

In layman's terms, chemical etching is to coat a wafer with photoresist, then remove the photoresist by exposure, and then use a corrosive material to corrode the exposed silicon wafer to finally form the structure required for the integrated circuit.

However, there is also a problem, the poor anisotropy of the etching solution used for wet chemical etching will cause a part of the wafer covered by the photoresist to be eroded. On the other hand, wet chemical etching has good isotropic properties, which can not only erode downward, but also erode left and right.

In this way, in the case of high precision requirements, this technology is obviously not suitable.

The first proposal was killed, which undoubtedly made others a lot more cautious. The person who wanted to speak also frowned on his face.

"Do the Americans have the ability to measure 100 nanometers? How did they achieve it?"

"Why not? Without this ability, how could the Hubble telescope go to the sky? The optical processing equipment of the Lawrence Laboratory has an accuracy of 10 nanometers and a positioning resolution of 1 nanometer, and it has already reached our finish line. ”

"1 nanometer accuracy, how did they achieve it!" The people who whispered below couldn't help but admire even when they heard the results of their competitors.

Lawrence Livermore Laboratories' optical lathes are arguably the most accurate machines in the world. As early as the eighties, in the process of developing the Hubble telescope, the US Air Force mastered the processing capability of ultra-precise large spherical surfaces with an accuracy of 100 nanometers and a diameter of 80 centimeters, which cleared the biggest obstacle for a series of later keyhole satellites.

"How did you do that? In order to reduce the impact of seismic waves on the equipment, the entire laboratory foundation is equipped with shock absorption, we don't even dare to think about this kind of thing, right?"

"Why don't you dare to think about it?"

No one expected that Wang Zhongjun, who had been silent in front, suddenly said a word.

"Isn't it just money, if installing shock absorbers in the house can improve the machining accuracy, then why don't we do it?"

"Put shock absorbers on the house...... Is it expensive?"

As soon as Wang Zhongjun said this, the people below were quiet for a moment, and then they all took a deep breath.

Oh, yes...... Is Xinke bad money?

The thinking of the following researchers is mainly not open. On the one hand, the previous work was done step by step, and the main direction was to explore the limits of existing technology. The shift from wet to dry etching, or to consider plasma etching further afield, is the latest development in the industry.

Another person is inevitably affected by the social environment, and this kind of input-output ratio that pays a lot of cost to reduce the very small error always feels like a bit of a loser.

Although Wang Zhongjun's laboratory has no shortage of scientific research funds every year, it takes imagination to spend money. 51

"Of course, it's not enough to install shock absorbers on the house for the time being. ”

Wang Zhongjun thought for a moment and said in a deep voice: "However, this is indeed a way. ”

The normal scientific research plan, of course, should consider economic benefits, and it is necessary to gradually develop and mature a technology, and then carry out the research and development of the next generation of technology.

Everyone knows that materials such as silicon carbide and gallium nitride have better performance than silicon wafers, but the semiconductor industry is not yet eating monocrystalline silicon, and it is not yet known in which year.

If the potential of monocrystalline silicon is not tapped and it is not economically unprofitable, how can the industry have the incentive to upgrade?

But the problem is that what Wang Zhongjun is facing now is not a normal R&D project.

Micro and nano nano gratings are not only tight in time and heavy in tasks, but also related to national strategies. It is at this time that we have the advantage of not talking about the so-called economic laws and doing our best to do one thing.

In the hearts of this generation of Chinese, the sense of mission of the times is still full of lofty spirit.

Cost should not be considered in Wang Zhongjun's project.

"We had to overturn the current technical path, and the machining accuracy of the etching method was not enough. We must have higher processing capacity, and we must jump out of the current semiconductor processing thinking ......"

"Higher processing capacity...... What about an atomic force microscope?"

Wang Zhongjun's self-talk made everyone a little dumbfounded.

"Director, how do you want to use an atomic force microscope? There are not many of them in our institute, and the director is baby!"

The atomic force microscope was indeed a rarity in China in the 90s, not only expensive but also difficult to buy. If there is one in the laboratory, it is like a computer room in the school, and I can't wait to cover it with a white cloth, and no one will use it.

Moreover, the application of atomic force microscope in China is still in the exploration stage, and it belongs to the kind of person who can scan a leaf casually and publish a paper in a journal.

With such a precious piece of equipment, I am afraid that Wang Zhongjun will open his mouth and occupy the share of other laboratories.

"There are three modes of operation of the AFM, which are non-contact, contact, and tapping mode. Wang Zhongjun's eyes suddenly brightened, and his smile was a little more confident: "If we set the progress of the tap mode to a negative number, in fact, its probe can be extremely fine processing on the material!"

"But ......"

Someone below couldn't help but shake his head: "In this way, the probe is also useless, right?"

The principle of an atomic force microscope is not complicated, it is to use a needle to "feel" an image. The needle can be in contact with the operating object, without contact, or quickly removed after contact – i.e. in tapping mode.

When the needle comes into contact with the object being scanned, a variety of forces exert influence in the process. By calculating this data, the scanned image can be obtained.

As you can imagine, such a probe must be very fragile. For example, the Institute of Semiconductors mainly observes hard materials, and most of the time they use non-contact mode, and even then, the probe is often damaged due to collision with material protrusions. Contact scanning is only used when looking at soft materials such as biological materials.

In normal use, if anyone dares to set the probe process to a negative number, then he will never want to enter the door of the laboratory in his life.

"No, IBM had used an atomic force microscope to manipulate a single atom a few years ago, so this route should be feasible. ”

"IBM only engraved three letters, we have to engrave hundreds of grating lines, the probe doesn't know how much to use, this cost difference is too big!" The researchers below are about to go crazy when they hear this, if this kind of experimental assumption is known by the director, the grating laboratory will have to be a cold bench for a lifetime!

"A probe is about two hundred dollars, and if we use imported probes, it's really too expensive. ”

"But the difficulty with this idea is not the cost, but the cost of money and the lack of off-the-shelf probes to use. In order to characterize the grating on monocrystalline silicon, we need a silicon probe so that the material is not contaminated during the scoring process. We also need needles with higher resolution and easier removal of impurities, which is difficult for silicon to achieve the resolution accuracy we need, in addition to new etching methods......"

Thinking of this, Wang Zhongjun not only did not worry, but breathed a sigh of relief.

Doing scientific research is not afraid of tiredness, not afraid of wasting brain cells, but afraid of not being able to find the way forward.

When he found this idea, he quickly listed the problems that needed to be solved in his mind. There are a lot of problems, and they are not small, but there is definitely a possibility of achieving them!

Just like Liu Cixin said in "Chaowen Dao", compared to the time it took for human beings to realize the existence of the universe, it was only a moment from Newton to the birth of Einstein.

"If that primitive man's gaze into the universe for a few minutes was to see a gem, then what you call the entire human civilization is just to stoop down to pick it up. ”