131. Chapter 130 Photosensitive Chip
Chapter 130 Photosensitive Chip
In fact, this incident was a big blow to Wu Lihong, and even made him think of retreating to the second line again.
But he was still unwilling to give up until he got the photoresist.
Now that Kang Chi was willing to help, it was naturally the best thing for him. But he was also afraid of disappointing Kang Chi’s trust and wasting his money, so he was a little hesitant.
“Although I know you have achieved some success and made a lot of money, money doesn’t come from the wind after all. Aren’t you afraid of losing it?”
”Of course, but will I stop doing research and development?” Kang Chi replied immediately, “Besides, I am not giving the money to your institute for free. I will also get a share of the results. In other words, it is like asking Academician Wu to help me work. Others can’t envy it, but I am worried that you will be unwilling to do it because of your face.”
”…”
Kang Chi’s words successfully amused Wu Lihong, and his worries were much less.
“Okay, I’ll discuss it with the institute later and try to help you get a better cooperation plan. Thank you for trusting me, an old man who is about to die.”
”Please don’t say such things.” Kang Chi said hurriedly, “In addition to photoresist, there are many etching materials waiting for you to show your skills… You have been researching for so long, and the benefits should be distributed as you want. There is no need to be partial. I am not here to take advantage of the situation.”
”In addition, this time I came here, I also wanted to borrow your laboratory to make a photosensitive chip, okay?”
”Photosensitive chip?” Wu Lihong asked in confusion, “Why are you suddenly interested in photosensitive chips again?”
”I want to help Daqin Optics make cameras.”
”…”
Sure enough, it has to be young people, they are full of energy.
Wu Lihong couldn’t help but sigh in his heart.
Including the oil-collecting insect project, he is already fighting on three fronts, right?
And each line is quite difficult.
”Can you handle this?”
”It’s OK, I’ll be fine after this period of time.” Kang Chi smiled, “It’s not urgent, just take your time, I’ll take a few more days of rest after this period of time.”
”Well, although you are still young, you should pay more attention to your health. There is still a long way to go in the future, so don’t rush…”
”Don’t worry, I know my limits.” – After the visit, Kang Chi followed Wang Haowen and went directly to the Jiangsu Microelectronics Research Institute, ready to borrow the equipment here to rub a simplified version of the photosensitive chip.
For Kang Chi, the camera should be a familiar thing. There are actually two core technologies in it, one is the CMOS photosensitive chip, and the other is the imaging system.
Although the remaining mechanical and electronic structures are also very precise, he was already familiar with them when he opened the repair shop. Now that he has accumulated so much professional knowledge, it is not difficult to reverse the camera.
The only thing that limited him from making a camera was the lack of a complete set of chip manufacturing equipment.
When wearing protective clothing with Kang Chi, Wang Haowen finally couldn’t help asking: “Brother Kang, you don’t seem to have prepared anything, just start working right away?”
”Is there a problem?”
”It’s a big problem, okay…”
Wang Haowen strongly doubted whether Kang Chi knew how to make chips…
Kang Chi just smiled and explained: “This time I just went through the process and verified the principle. Even if I make a CMOS with only 100 pixels, it doesn’t require such complicated steps.”
”One hundred pixels?!”
Wang Haowen was shocked.
But when I think about Kang Chi’s first time making chips, he gave him a 2D acceleration card to verify his so-called “principle”.
I can only say that the research method of the great god is different from that of ordinary people like you.
Of course, 100 pixels is just an exaggeration by Kang Chi. It depends on the actual situation here to try to make a photosensitive chip with better performance.
Although he has no shortage of general experience for upgrading,
but he should save as much as possible, as he never knows when it will come in handy.
The structure and principle of CMOS photosensitive chips are actually simpler than ordinary chips, and the technical difficulties are mainly reflected in the manufacturing process and materials.
From a design perspective, photosensitive chips can be said to be completely easy to use, and are a type of chip with a very high repetition rate of drawings.
For exampleA photosensitive chip with 20 million pixels actually has the same chip structure for each pixel. As long as photolithography is used on the silicon wafer substrate to create uniformly arranged photodiodes, and then a color filter is made on this diode through etching.
The specific working principle is actually not difficult.
We can imagine the color filter as a window with four square glasses. The colors of these four glasses are red, green, blue, and green.
Then when the light outside shines through the glass into the house, the four photodiodes arranged in the house can restore the color and brightness of the incoming light by identifying the light intensity of the four areas.
In other words, a 20 million pixel CMOS requires 80 million photodiodes and color filters.
And in order to ensure that the light conditions for absorbing light are the same for each pixel, they can only be arranged flat on the silicon wafer, and cannot be stacked into a complex urban structure through etching like other chips.
That is why it is very difficult to achieve high pixel count on photosensitive chips.
It is really too demanding on the manufacturing process.
If a 90-nanometer lithography machine is used to make photodiodes, because of the principle of a 2X2 pixel, it is equivalent to a 180-nanometer process. And because it can only be tiled, under the condition of chip size restrictions, the number of pixels can only be reduced.
So some mobile phone manufacturers brag that their mobile phones have 100 million pixels.
In fact, it is just for fun.
Think about it, with a lens as small as a mobile phone, how big can the area of the CMOS chip inside be? Even if the most advanced EUV lithography machine is used to make it, the photodiode inside will never reach the level of 400 million tiles.
It is actually estimated that it will not even reach 10 million.
The remaining pixels are all fake pixels calculated by the processor to make people happy.
Moreover, the smaller the process, the more difficult it is to etch the color filter, and the material used for dyeing in etching: color photoresist, has more stringent performance requirements.
However, Kang Chi’s current requirements are not high. Just rub it and make as many pixels as possible.
There are no requirements for the performance of the color photoresist. Wang Haowen is directly asked to mix it. The only requirement is that red, green and blue cannot be distinguished…
Although he came to rub it by the way, in fact, Kang Chi still stayed in Lin’an for almost a week.
The main reason is that the production of the mask plate is time-consuming. At the same time, because it is only a one-time one, in order to pursue cost-effectiveness, Kang Chi had to lower its precision requirements.
[Item: Photosensitive chip]
[Manufacturer: Kang Chi]
[Item level: 1]
[Experience: 0/500]
[Item status: intact]
[Item parameters: 500,000 pixels]
[Analysis items: no analysis items]
[General experience: 50314]
[Mastery points: 12.3]
Looking at the low-energy chip in his hand, which is the same size as a 135mm frame photosensitive chip but has only 500,000 pixels, Kang Chi couldn’t help but sigh again that chips really burn money.
This tape-out cost Kang Chi nearly two million,
And this is already considered a cost-saving. If he had just made a set of mid-range process masks, it would have been a waste of tens of millions of dollars, and it would also waste more time.
Wang Haowen saw Kang Chi put the finished chip directly into the container, ready to leave, and asked in confusion: “Don’t you want to test it?”
”Test?”
The system panel has popped up, what else is there to test?
Kang Chi laughed: “No, I have already tested it in my mind.”
Wang Haowen: “???”
(End of this chapter)