Siheyuan: Starting from a fitter

Chapter 119: Laying out the Semiconductor Industry

It was already past 1 o'clock in the middle of the night when I got home. Without disturbing Zhao Ting, who was sleeping soundly, she sat there and reorganized the semiconductor ideas she had thought about in the past.

Li Guocheng’s plan for the semiconductor industry is R&D-realization-investment in R&D-realization. . . , keep repeating.And it is necessary to ensure that part of the funds after realization can continue to be invested in research and development.

Now it is all investment. Purchasing high-purity silicon powder and manufacturing vacuum furnaces, slicers and grinders are the first stage of his planning. Next, he will consider monetization.

首都无线电仪器厂仿照东亚岛国的某个型号半导体收音机，采用了8个三极管和1个二极管。1964年9月30日正式在首都王府井百货大楼上市，价格是158元。

Since monocrystalline silicon is not pure enough, with only 4 to 6 nines, and precision is the main factor affecting the yield of transistors, the yield of transistors has always been low, resulting in high costs.

The semiconductor preparation method designed by Li Guocheng adopts the mature rotation pulling method of later generations. According to later generations, the purity of the single crystal silicon obtained is as high as 99.999999%, which is commonly known as eight nines of single crystal silicon.At present, it should be the purest monocrystalline silicon in China and even in the world.If necessary, it can be purified again through a high-frequency furnace.

Such high-purity single crystal ingots can greatly improve the yield of products, thereby reducing the manufacturing cost of transistors.So selling wafers is the next main task.

Before sale, the wafer needs to be surface oxidized to protect the wafer.Oxidation equipment can be modified based on vacuum furnaces, which is relatively simple.

The vacuum furnace that comes as an accessory can also be sold as a product and can be monetized.It is only necessary to remove the lifting rod and design versions of different sizes according to user needs. It is estimated that the supply will exceed the demand.

How to operate specifically and how to communicate with relevant departments is a matter for Wu Liankui and Li Huaide.

The vacuum furnace is handed over to Wang Gong for their production, which can be used as an overproduction of machine tools.But wafer production still requires the formation of a team on the laboratory side.

It seems that Zhang Tou and Wang Dayong don't need Wang Gong's arrangements and can come directly to help produce wafers.

After all these arrangements were made, Li Guocheng wanted to think about the next research work, which was to manufacture special chips.In order to be easily monetized, you can consider directly manufacturing special chips for AM and FM radios.

Integrating the amplification and detection (demodulation) circuits of the radio into the chip, and then providing a radio solution, can directly replace the current tube and transistor radios.

Manufacturing chips mainly has the following steps: wafer processing, oxidation, photolithography, etching, thin film deposition, interconnection, testing and packaging.

The equipment for wafer processing is now available, and the oxidation equipment can be easily modified. The difficulty lies in the subsequent processes.

Photolithography is subdivided into three processes: applying photoresist, exposure and development, which is similar to the principle of photography.

Apply photoresist: The first step in drawing circuits on a wafer is to apply photoresist on the oxide layer.Photoresist turns the wafer into "photographic paper" by changing its chemical properties.The thinner the photoresist layer on the wafer surface and the more uniform the coating, the finer the graphics that can be printed.

Exposure: Exposure equipment selectively passes light. When the light passes through a mask containing circuit patterns, the circuit can be printed onto a wafer coated with a photoresist film below.

The mask is the copper plate on which the circuit is printed, and the light passes through the engraved copper plate to be printed on the wafer.

The finer the printed pattern during the exposure process, the more components the final chip can accommodate, which helps increase production efficiency and lower the cost of individual components.In this field, a new technology that has attracted much attention in later generations is EUV lithography.

Development: The step after exposure is to spray developer on the wafer. The purpose is to remove the photoresist in the areas not covered by the pattern, so that the printed circuit pattern can be revealed.

After knowing the above photolithography process, etching is easy to understand. It is to wash away the non-circuit parts through chemical reactions.

Thin film deposition can now use doping thermal diffusion methods, which are very easy to implement processes.

Doping is to add a certain amount and type of impurities into silicon to obtain a precise impurity distribution shape.When a piece of single crystal silicon is doped with phosphorus, an N-type semiconductor is formed, and a semiconductor doped with boron atoms is a P-type semiconductor.

The thermal diffusion method is to thermally diffuse the atoms of the material to be doped into the semiconductor at a high temperature of 1000° to form an N-type semiconductor or a P-type semiconductor.

For interconnection, the aluminum wire diffusion method is used, and the same equipment as the above process can be used.

There is currently no good way to test, other than optical naked eye inspection.

Packaging is when all the chips are separated from the wafer, we need to attach the individual chips (individual wafers) to the substrate (lead frame).The purpose of the substrate is to protect the semiconductor chips and allow them to exchange electrical signals with external circuits.

Use gold wires to connect the electrodes of the chip to the external metal pins, set them like a grinding tool, inject plastic solution, and after cooling, the packaging process is completed.

The specific aspects of photoresist, developer and etching solution can be left to professionals.As for photolithography equipment and heat treatment equipment, they can only be designed and manufactured by Li Guocheng.

I know that the process of craftsmanship in later generations is so rogue, reaching the goal directly without taking detours.

As long as you take the first step, you can continue to manufacture special chips, and then upgrade the process to improve the chip yield and reduce manufacturing costs.

Now that the West is still in the exploratory stage, we can manufacture relevant equipment in advance and continuously optimize the process during production to achieve rapid overtaking.

Achieving this step will achieve Li Guocheng's first stage goal.

The next step is to use these equipment to start designing and manufacturing computers in the secret laboratory.

Li Guocheng, the computer, dare not appear in the world too early for the time being. Special-purpose chip research is being done all over the world. It will be no problem for us to be a little faster. If we develop a killer computer, it may not necessarily have any consequences.

In future generations, Huawei is the best example. We must not show our fangs and muscles until we grow up.

All plans need to be communicated with Mr. Zhao and must obtain the support of him and Dad Zhao.

It was already 3 o'clock in the morning. I put on my clothes and lay down, and soon fell asleep.

The next day, three people were sitting in Li Huaide's office, Li Huaide, Wu Liankui and Li Guocheng.

Li Guocheng told the whole story about yesterday's method of cashing out, waiting for their response.

"There is a semiconductor boom in the country right now. If it is true as Xiao Li said, there is a lot of potential for wafer production." Li Huaide made up his mind after thinking for a while.

"Xiao Wu, hurry up and write a report. You and I will report to the ministry in the afternoon and try to get approval as soon as possible."

Then someone looked at Li Guocheng and said, "Xiao Li, please work with Wang Gong as soon as possible to produce five more vacuum furnaces and oxidation furnaces as soon as possible, and you must increase the wafer output."

Looking at the backs of the two people leaving, Li Huaide couldn't help but rub his temples, "This Xiao Li's movements are too fast. Following the successful development of the Shuguang 1966 machine tool, the Shuguang II machine tool was soon launched. Now it is even more so fast. We have developed popular semiconductors across fields. If the timing was not right now, semiconductors would not dare to report, otherwise the steel rolling mill would be put on fire."

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(End of this chapter)