Guo Dong and a few of them, when they arrived at the experimental workshop, Guo Dong, as the person who did not understand liquid crystal technology on the spot, asked several other people: "How does the liquid crystal control the switch, and how does it display the circuit graphics?"

"Liquid crystal is a compound substance between solid and liquid at room temperature discovered by the Austrian botanist Leiniz as early as 1888.

Later, until 1968, the engineers of the Shanov R&D Center of the American company RcA discovered that liquid crystals were affected by voltage and changed their order, and they used this phenomenon to invent the first LCD screen.

As for how to display the graphics, it is to place the liquid crystal in the parallel glass panel grooves, such a glass panel has two pieces, and the front and back two rows of grooves are 90 degrees perpendicular, so that they constitute cells, that is, pixels. In the middle of the two rows of grooves are transparent electrodes in the shape of a mesh.

If we electrify the horizontally arranged trenches, then the liquid crystals in the grooves will be arranged sequentially along the grooves, and the background light source can pass through them. But there is also a layer of longitudinally arranged liquid crystals that are not electrified, so they are arranged in a chaotic manner, and the light still can't pass. If, at this time, we electrify one of the grooves arranged vertically, then the point where the vertical and horizontal arrangements intersect, where the light can actually pass through, and many such bright spots form the figure.

Of course, real liquid crystal technology will not be so simple, but we only need such a simple technology now. If it's complicated, it's not good, and it will affect the image accuracy. Speaking of liquid crystal, it is Wang Bo's dish, so he popularized science to Guo Dong a little.

"I see! Now I understand. Guo Dong nodded as he spoke, as if he had completely understood.

As long as the first generation of liquid crystal technology is simple, of course, they need to be simpler than the first generation technology, so there is no difficulty. The only thing they had to solve was the precision of the grooves, making the pixels more dense.

However, compared to Changsheng Seiko, which has nanoscale processing technology, it is too simple. Because no matter how precise the groove is, it is only at the U meter level, which is determined by the size of the molecules of liquid crystal compounds.

When the first LCD screen was trial-produced, after understanding the technical details, Guo Dong sighed and said: "It seems that the shortcomings of this technology are also obvious, it can only achieve U-meter level accuracy, and we are busy in vain." ”

"I can't say that, in fact, in daily life, low-level chips are used the most, such as chips used in ordinary small household appliances and ordinary industrial control chips. It's also a great step forward that we're able to reduce the number of low-level chips. At this time, the authoritative expert Hong Tao stood up to cheer everyone up.

"Alas, okay! Let's try it first! I don't know if we can replace laser etching?" Guo Dong sighed again, he was really a sentimental person.

It's very easy to try, because it is not a silicon wafer, so there is no need for an oxygen-free environment, just a darkroom. The darkroom is not really dark, and the yellow light is still okay.

They experimented, and the situation was okay, as long as the mask panel and the LCD screen were close enough, about a few nanometers, the diffusion of light was still not serious. In other words, the use of LCD screen instead of laser etching mask has been successful, although it can only be used in low-process chip technology, but because of the fast transfer of graphics, it can be said to be a very useful technology.

The next step is to actually develop the lithography machine. Due to some technical difficulties, Guo Dong had already solved them when they were still in the technical department of Changsheng Seiko, so they directly entered the design process.

In order to maximize efficiency and reduce argon consumption, Guo Dong asked the technician to set the maximum stroke of the movable mechanism in the workbench to 5 mm. That is to say, there is only 5 mm from the top laser to the bottom of the substrate surface, and there is a notched bracket in the middle of this 5 mm, and the bracket is a platform for the mask template, which can only move up and down. And that notch is used for the micro robotic arm to convey the mask.

The mask plate must be at least one millimeter thick, and the bracket must be at least two millimeters thick, plus the micro robotic arm takes up a little bit of thickness, that is to say, in the process of transporting the mask plate, the difference between the laser head above and the substrate below is less than one millimeter, and the play is so precise.

Of course, the silicon wafer substrate, it is put in last, and the micro robotic arm is fed in from below, which does not occupy the 5 mm of working space.

The silicon wafer substrate table is truly fixed and it does not need to be moved. The only thing that can move up and down, left and right is the laser head. There is not just one laser head, but a row. Just like swiping a card, it only takes one swipe to swipe.

It seems very simple, but in fact, the most difficult thing for him is how to control the difference between the mask and the substrate is only a few nanometers, and the difference between the laser head and the mask is only a few nanometers. It is this difficulty that stumps Xu Company, which requires nano-scale processing technology to do. And it just so happens that Changsheng Investment Group can do it, and the reason is as simple as that.

There is not just one, but many blocks. Therefore, he has another set of positioning mechanisms, just like the tool change system of the machine. In order to save space to the maximum, it is parallel to the perimeter of the workbench, it can circle around, and according to the instructions of the computer, the mask plate required for the next block can be transported to the front of the micro robotic arm. The principle is similar to the CNC tool change system of the machine tool.

Why is the workbench set so thin? It is to reduce the time spent on moving up and down, and also to reduce the potential energy of movement, which correspondingly increases the control accuracy of up and down movement.

At this time, if you only look at it from the perspective of lithography machines, the chip manufacturing process technology of Changsheng Investment Group has exceeded the world level in 2017. Guo Dong's lithography machine can even reach the process process of less than 10 nanometers, of course, the laser head needs to be improved to a focused laser head. But from a purely mechanical point of view, they really got there.

However, the chip manufacturing process is a systematic project, not a simple mechanical accuracy is enough, in fact, the most restricting process is the chemical etching link. I'll go into more detail in a future chapter.

In previous industrial articles, some authors mentioned that immersion laser technology can double the etching accuracy. That's because of the era at that time, the laser accuracy was low, and the ultra-deep ultraviolet light used by Changsheng Investment Group was only developed in 2016, and the laser accuracy was improved dozens of times at once, which is far from being comparable to the immersion laser head technology.

The lithography machine was successfully developed, Guo Dong and his team conducted many experiments, and found that the etching accuracy is very high, which has completely met or exceeded the requirements. Hong Tao even bluntly said that his own technology has far surpassed that of the United States, and it makes sense for him to say so.

He is a Ph.D. in electronic engineering in the United States, and he has seen a lithography machine in the United States. They also know their chip manufacturing process level. Although many years have passed, he speculates based on Moore's Law that his own technology is far superior to that of the United States by several orders of magnitude.

Guo Dong and the others reported the good news to Shen Danqing as soon as possible, and Shen Danqing immediately came to Changsheng Seiko. He listened carefully to Guo Dong's explanation on the spot, and nodded with satisfaction, as diligent as a chicken pecking rice, completely unaware that this would hurt his neck.

He is so happy, the lithography machine was a short board in China until 2017, and now that their company has developed it, it can be said that it has made up for China's shortcomings, can he not be happy? This is not something money can do. He imagined that in the future, China's annual chip import quota of hundreds of billions of dollars would be gone, so what would happen to China? The picture was so beautiful that he didn't dare to imagine it anymore.

After retracting his mind and stabilizing his emotions, he asked Guo Dongdao again: "How is the development of the ion implanter?"

"I'm sorry, boss, I don't know?" Guo Dong was speechless when asked, his mind was all devoted to the development of lithography machines, where did he know about the situation of the other group.

Fortunately, at this time, Lu Rucheng hurriedly came to remedy, and he hurriedly said to the boss: "Boss, we are grouped, and we are all focused on developing the lithography machine, and we will report to you as soon as we have the results." Therefore, the situation of the other group is not yet known. I beg your forgiveness. ”

Hearing Lu Rucheng's explanation, Shen Danqing's face immediately turned cloudy and clear, so he smiled and said to them: "If that's the case, it's no wonder that you don't hear anything outside the window, this is a common problem of all scientific researchers! Hahahaha! Okay! You have solved it here, let's go and see the situation of the other group!"

However, his good mood did not last long, and when he came to the other group, they were still in the stage of theoretical research, which made him almost roar into anger: "How did you do it? The other group of lithography machines has been successfully developed, and even the LCD screen etching technology has been developed, but you have not even started the experiment! It seems that none of you have a good head, you are all working on your own affairs, and you only care about it. Due to the actual situation of ion implanters, the Physics Research Institute accounts for the largest proportion, and I will now make it clear that Director Wang of the Physics Research Institute will be the person in charge of this research and development task. Or adopt the business department system, Director Wang is the head of the business department, and he has the right to transfer anyone and materials in the whole group. No one is allowed to object or obstruct me, otherwise I will punish him severely. ”

Then he said to Wang Weihong in a stern tone: "Director Wang, I have given you the greatest right, I just need you to give me the result quickly, can you do it?"

Wang Weihong and the people present except for the lithography machine development team had already been frightened by the boss's anger, and the boss asked him so harshly, he could only reply tremblingly: "Yes...... I can...... Boss, I'm sure I can. ”

The last sentence is both an answer to the boss and a boost to yourself. The boss's aura is too strong, and he is a new director with no qualifications, and he can't bear it!

……