Silicon dioxide powder is made of natural quartz (SiO2) or fused quartz (amorphous SiO2 after high temperature melting and cooling of natural quartz) after crushing, ball milling (or vibration, jet milling), flotation, pickling purification, high-purity water treatment, etc. Micro powder processed by the technology.

Spherical silicon micropowder is mainly used for the packaging of large-scale and very large-scale integrated circuits. According to the integration level (the number of standard components per integrated circuit) to determine whether the spherical silicon micropowder is spherical or not, when the integration level is 1M to 4M, the spherical silicon powder has been partially used Powder, from 8M to 16M, all spherical powder has been used. At the level of 250M, the line width of the integrated circuit is 0.25μm. At the level of 1G, the line width of the integrated circuit has been as small as 0.18μm. The CPU chip of the current computer PIV processor has reached this level. The spherical powder used at this time is of higher grade, mainly using the scraps of polysilicon to make ethyl orthosilicate and silicon tetrachloride to hydrolyze to obtain SiO2. It is also made into a spherical shape with a particle size of -(10-20) μm. Tune. The chemically synthesized spherical silicon powder is 10 times more expensive than the spherical powder made of natural quartz raw materials. The reason is that this powder is basically free of radioactive alpha radiation pollution and can achieve a uranium content of less than 0.02PPb. When the concentration level is large, because the wire spacing between the VLSI circuits is very small, and the packaging material has a large radioactivity, source errors will occur when the integrated circuits are working, which will affect the reliability of the VLSI circuits. strict requirements. The natural quartz raw material reaches (0.2～0.4) PPb is a good raw material. The spherical powder currently used in China is mainly spherical powder made of natural raw materials, and it is also imported powder.

Generally, integrated circuits are etched on monocrystalline silicon wafers by photolithography, then connected to the lead and tube corners, and then packaged with epoxy molding compound. The closer the thermal expansion rate of the plastic molding compound is to that of monocrystalline silicon, the better the thermal stability of the integrated circuit. The melting point of monocrystalline silicon is 1415℃, the expansion coefficient is 3.5PPM, the fused silica powder is (0.3～0.5)PPM, the epoxy resin is (30～50)PPM, when the fused spherical quartz powder is added with epoxy in a high proportion When the plastic molding compound is made from resin, its thermal expansion coefficient can be adjusted to about 8PPM. The more it is added, the closer it is to the monocrystalline silicon wafer, and the better. The thermal expansion coefficient of crystalline powder, commonly known as raw powder, is 60PPM, and the melting point of crystalline quartz is 1996℃, which cannot replace fused silica powder (ie, fused silica powder). Therefore, when spherical powder is not used in high- and mid-range integrated circuits, molten angular silicon should be used. Micropowder. This is the reason why the high-grade spherical powder cannot be successfully shaped into a nearly spherical shape with crystalline powder. Japan also walked this way in the 1980s, but it didn't work, it didn't work; 10 years ago, including now in our country, people still walked this way. The above theory proved that this method is not feasible. That is, the high-grade molding compound powder cannot be replaced by crystal powder.

Is it better to use fused silica (that is, high-purity quartz glass) or crystalline quartz as the raw material to produce high-purity spherical quartz powder? According to the experiment, experts believe that this question is already clear. Using natural quartz SiO2, high-temperature melt spraying to make balls, fused spherical quartz powder can be obtained. The powder is made of natural crystalline quartz, and then after dispersion, the ball made by plasma flame is the molten ball. The ball made by burning the powder with flame has smooth surface and shrinkage in volume. It is better to use. This kind of powder provided by Japan, X-ray spectroscopy is used to analyze the spectrum line is flat, and it is also a fully fused spherical quartz powder, while domestic electric fused quartz, such as Lianyungang’s fused silica spectroscopic analysis, has an amorphous content of 95%, and the spectrum can still be seen to have sharp peaks. 5% is not melted. It can be seen that in the production of spherical quartz powder, as long as the purity can meet the requirements, it is good to use natural crystalline quartz as the raw material, its production cost is low, and the process route is simpler.

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