With the rapid development of microelectronics industry, demands for large-scale and ultra large-scale LSI packaging materials are also increasingly high. It not only asks for its ultra-fine, but also the high purity and low radioactive element content.
It is especially for spherical particle shape. High purity and ultrafine molten spherical quartz powder (referred to the spherical silica powder) because of its high dielectric, high heat, high humidity, high filler content, low thermal expansion, low stress, low impurities and low coefficient of friction, it has become an indispensable quality material in large-scale, LSI substrate and the encapsulation compounds for metal powder supplier.
Spherical silica powder is mainly used for large-scale and ultra large scale integrated circuit package according to the set level (the number of each integrated circuit standard components) to determine whether the spherical silica powder, when set for the 1M to 4M, has been part of the spherical powder 8M to 16M set extent, they have all the spherical powder. 250M sets the level of the integrated circuit line width is 0.25¼m, when the degree of 1G set, the integrated circuit line width has to 0.18¼m, Computer P-IV processor CPU chip, to reach such a level. Then the spherical powder is more upscale, the main use of polysilicon scraps is made to orthosilicate acetate and silicon tetrachloride hydrolysis of SiO2, also made of the spherical particle size for the (10 ~ 20) ¼m in adjustable. Spherical powder of the chemical synthesis of spherical silica powder made of natural quartz raw materials to 10 times more expensive, because this powder is basic that no radioactive alpha-ray contamination, uranium content can be achieved following 0.02PPb. Set the degree of LSI between the wire spacing is very small, the packaging materials radioactive large IC work will produce the source of error, make LSI reliability affected, and therefore must of radioactive stringent requirements. Natural quartz raw materials of (0.2 ~ 0.4) PPb on good raw materials. Spherical silica powder is made from natural raw materials of spherical powder, and also imported powder.
General IC is a lithography method to focus on the circuit engraved on the monocrystalline silicon. And then the connecting leads and tube angle, and then the epoxy molding compound package from. The plastic materials of thermal expansion of silicon the closer the better of the integrated circuit thermal stability. Monocrystalline silicon melting point of 1415 , expansion coefficient 3.5PPM, fused silica powder (0.3 to 0.5) PPM, the epoxy resin (30 ~ 50) PPM when molten spherical quartz powder by adding a high proportion of epoxy resin made of plastic material, the thermal expansion coefficient is adjustable to about 8PPM, plus the more the more close to the silicon wafer, the better. The thermal expansion coefficient of crystalline powder commonly known as cornstarch 60PPM, the melting point of crystalline quartz for the 1996 ° C can not replace the fused silica powder (fused silica powder), high-grade integrated circuits do not have a spherical powder, but also angular silicon molten powder. That is the reason why this high-end spherical powder under the help of crystalline powder shaping can not become spherical successfully.
Using natural quartz SiO2, the ball can be made under high-temperature molten jet. It can obtain completely molten spherical quartz powder. The natural crystalline quartz can make the powder, then disperse molten ball is a ball made of flame ionization, flame burning powder obtained by the ball, the surface is smooth with volume contraction, better use this powder in Japan, completely flat X-ray spectroscopy spectrum, but also the entire molten spherical quartz powder, electric melting quartz, 95% amorphous content such as Lianyungang, fused silica spectrum, the lines can still be seen the peak, is still 5% did not melt. Thus, in the production of spherical silica powder, as long as the purity can reach the requirements, the natural crystalline quartz is the best raw material. Its production costs are lowest and it has more simple process route.Source:http://www.mhcmp.com
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