Simply put, it is like this:
The main component of sand is silicon dioxide.
In industry, carbon monoxide is smelted to produce carbon dioxide and crude silicon.
The general method of purification is smelting. In fact, the details of many effective crude silicon purification methods are industrial secrets or patents.
The following is the details of Si in the computer.
CPU (Central Processing Unit), as the core component of computer, has always been very mysterious in the eyes of users: in the eyes of most users, it is just a noun abbreviation, and they can't even spell it; In the eyes of some hardware experts, the CPU is at most a block with a dozen square centimeters and many feet, and the core part of the CPU is even less than one square centimeter. They know how many microns this thing, which is less than one square centimeter in size, is made. They know that it integrates hundreds of millions of transistors, but few people know the manufacturing process of CPU. Today, we will learn more about how the CPU is practiced.
Basic materials
As we all know, modern CPU is made of silicon. Silicon is a nonmetallic element. From the chemical point of view, because it is located at the junction of metal element region and nonmetal element region in the periodic table, it has the properties of semiconductor and is suitable for manufacturing all kinds of tiny transistors. It is one of the most suitable materials for manufacturing modern large-scale integrated circuits. In a sense, the main component of sand on the beach is also silicon (silicon dioxide), and the silicon material used to produce CPU is actually extracted from sand. Of course, some other materials will be used in the manufacturing process of CPU, which is why we won't see Intel or AMD just pulling tons of sand to their manufacturing plants. At the same time, the manufacture of CPU needs very high-purity silicon material, although it comes from cheap sand, because of the complexity of material purification process, we still can't compare the price of 100 g of high-purity silicon with one ton of sand.
Another basic material for making CPU is metal. Metal is used to make circuits that connect various components inside the CPU. Aluminum is one of the commonly used metal materials, because it is cheap and its performance is not bad. At present, the mainstream CPU mostly uses copper instead of aluminum, because the electromigration of aluminum is too great to meet the needs of the rapidly developing CPU manufacturing process. The so-called electromigration means that a single atom of metal moves out of its original position under certain conditions (such as high voltage).
Obviously, if atoms are constantly removed from the metal microcircuit connecting elements, the circuit will soon be riddled with holes until it breaks. This is why the poor CPU often went into shock and even died of Sudden Death Syndrome (SNDS) when the overclocker tried to greatly increase the voltage of Northwood Pentium 4. SNDS enables Intel to apply copper interconnection technology to the production process of CPU for the first time. Copper interconnection technology can obviously reduce electromigration phenomenon, and at the same time, it can be smaller than the circuit manufactured by aluminum technology, which is also a problem that can not be ignored in nano-scale manufacturing technology.
Moreover, the resistance of copper is much smaller than that of aluminum. All kinds of advantages make copper interconnection technology quickly replace aluminum and become the mainstream choice of CPU manufacturing. In addition to silicon and some metal materials, there are many complex chemical materials also involved in the manufacture of CPU.
Preparatory work/about to start work
After solving the material problem of manufacturing CPU, we began to enter the preparatory work. In the preparation process, some raw materials will be processed to make their electrical properties meet the requirements of manufacturing CPU. One is silicon. First, it will be purified by chemical methods, so pure that there are almost no impurities. At the same time, it has to be transformed into silicon crystals, which is essentially a clear line with the sand on the beach.
In this process, the raw material silicon will be melted and put into a huge timely furnace. At this time, the seed crystal is put into the furnace, so that the silicon crystal can grow around the seed crystal until almost perfect monocrystalline silicon is formed. If you have done a good job in the experiment of copper sulfate crystallization in high school, or have seen how single crystal rock sugar is made, I believe this process is not difficult to understand. At the same time, you need to understand that many solid substances have a crystal structure, such as salt. The same is true of silicon in CPU manufacturing. Carefully and slowly stir the molten slurry of silicon, and silicon crystals grow in the same direction around the seed crystal. Finally, the silicon ingot is produced.
At present, the diameter of silicon ingots is mostly 200 mm, and CPU manufacturers are going to manufacture silicon ingots with a diameter of 300 mm. Under the premise of ensuring the same quality, it is obviously more difficult to manufacture larger silicon ingots, but the input of CPU manufacturers has solved this technical problem. It will cost about $3.5 billion to build a factory to produce 300mm diameter silicon ingots, and Intel will use its silicon materials to make more complex CPU. It only costs $6543.8+$500 million to build a similar factory to produce 200mm diameter silicon ingots. As the first person to eat crabs, Intel obviously needs to pay a higher price. It seems uneconomical to spend more than twice as much money to build such a factory, but as can be seen from the following, the investment is worthwhile. There are many methods for manufacturing silicon ingots, and the above is just one of them, which is called CZ manufacturing method.
Silicon ingots are made, molded into a perfect cylinder, and then cut into small pieces, called wafers. Wafers are really used in the manufacture of CPU. Generally speaking, the thinner the wafer is cut, the more CPU products can be made with the same amount of silicon material. Next, the wafer will be polished and inspected for deformation or other problems. Here, quality inspection directly determines the final yield of CPU, which is extremely important.