Then, the raw materials are melted at high temperature. We learned in middle school chemistry class that atoms in many solids are crystal structures, and so is silicon. In order to meet the requirements of high-performance processors, the whole silicon raw material must be high-purity monocrystalline silicon. Then the silicon raw material is taken out from the high-temperature container by rotation and stretching, and a cylindrical silicon ingot is made at this time. According to the process used, the circular cross-section diameter of silicon ingot is 200 mm, however, Intel and other companies have started to use 300 mm diameter silicon ingots. It is quite difficult to increase the cross-sectional area without changing the characteristics of silicon ingots, but it can be achieved as long as enterprises are willing to invest a lot of money in research. The factory built by Intel to develop and produce 300mm silicon ingots costs about $3.5 billion. The success of new technology enables Intel to manufacture integrated circuit chips with higher complexity and more powerful functions. The 200 mm silicon ingot factory also spent1500 million dollars. The manufacturing process of the chip is introduced from the slicing of silicon ingot. The new chip should be doped with some substances to make it a real semiconductor material, and then transistor circuits representing various logic functions should be engraved on it. Doped substance atoms enter the gaps between silicon atoms, and atomic forces interact, thus making silicon raw materials have the characteristics of semiconductors. Multi-choice CMOS process (complementary metal oxide semiconductor) is used in semiconductor manufacturing today. The word complementary represents the interaction between N-type MOS transistor and P-type MOS transistor in semiconductor. N and p represent the negative electrode and the positive electrode in electronic technology respectively. In most cases, the P-type substrate is formed by slicing and doping chemicals, and the logic circuit engraved on it should be designed according to the characteristics of nMOS circuit. This kind of transistor has higher space utilization rate and more energy saving. At the same time, in most cases, it is necessary to limit the appearance of pMOS transistors as much as possible, because in the later stage of the manufacturing process, N-type materials need to be implanted into P-type substrates, and this process will lead to the formation of pMOS transistors.
After the dosing work is completed, the standard section is completed. Then each slice is heated in a high temperature furnace, and a silicon dioxide film is formed on the surface of the slice by controlling the heating time. By closely monitoring the temperature, air composition and heating time, the thickness of the silicon dioxide layer can be controlled. In Intel's 90 nm manufacturing process, the width of the gate oxide is as small as 5 atoms. This gate circuit is also a part of transistor gate circuit. The function of transistor gate circuit is to control the electron flow in it. By controlling the gate voltage, the electron flow is strictly controlled regardless of the voltages at the input and output ports. The last step of preparation is to cover the photosensitive layer on the silicon dioxide layer. This material layer is used for other control applications in the same layer. This layer of material has a good photosensitive effect after drying, and can be dissolved and removed by chemical method after the lithography process. This is a very complicated step in the process of chip manufacturing. Why do you say that? Photolithography process is to use a certain wavelength of light to carve a corresponding notch on the photosensitive layer, thus changing the chemical characteristics of the material there. This technology is very strict with the wavelength of the light used, which requires the use of short-wavelength ultraviolet rays and lenses with large curvature. The etching process is also affected by stains on the wafer. Every step of etching is a complicated and delicate process. The amount of data needed to design each process can be measured by 10GB, and the etching steps required to manufacture each processor are more than 20 steps (etching one layer at a time). Moreover, if the etching map of each layer is magnified many times, it can be compared with the map of new york plus suburbs, or even more complicated. Imagine reducing the map of new york to a chip with an actual area of only 100 square millimeter. You can imagine how complicated the structure of this chip is.
When all these etching jobs are completed, the wafer is turned over. Short wavelength light shines on the photosensitive layer of the wafer through the hollowed-out gap on the timely template, and then the light and the template are removed. The exposed photosensitive layer material is removed by chemical method, and silicon dioxide is generated right below the hollow position. From this step, you will continue to add layers, add silicon dioxide layers, and then photoetch once. Repeat these steps, and then a multi-layer three-dimensional architecture will appear, which is the embryonic state of the processor you use. Conductive connection between layers is realized by metal coating technology. Today's P4 processor uses 7 layers of metal connections, while Athlon64 uses 9 layers. The number of layers used depends on the original layout design and does not directly represent the performance difference of the final product.
In the next few weeks, we need to test the wafers one by one, including the electrical characteristics of the wafers to see if there are any logical errors, if so, which floor, and so on. Then, each defective chip unit on the wafer will be tested separately to determine whether the chip has special processing requirements.
Then, the whole wafer is cut into individual processor chip units. In the initial test, those units that failed the test will be abandoned. These cut chip units will be packaged in some way, so that they can be successfully inserted into the motherboard of a certain interface specification. Most Intel and AMD processors are covered with heat sinks. After the processor is completed, it is necessary to carry out all-round chip function test. This company will produce different grades of products. Some chips have relatively high operating frequency, so the names and numbers of high-frequency products are marked, while those chips with relatively low operating frequency are modified and marked with other low-frequency models. This is the market positioning of different processors. Moreover, some processors may have some shortcomings in chip functions. For example, if it has a defect in cache function (this defect is enough to paralyze most chips), then they will be shielded from some cache capacity, which will reduce performance and of course reduce the price of the product. This is the origin of Celeron and Sempron.
After the chip packaging process is completed, many products need to be re-tested to ensure that the previous manufacturing process is not omitted, and the products fully meet the specifications and have no deviation.