High-purity ultra-fine electronic grade quartz powder
In semiconductor integrated circuit packaging, packaging materials can play a role in semiconductor chip support, chip protection, chip heat dissipation, chip insulation, and interconnection of the chip with external circuits and optical paths. In electronic packaging materials, filler occupies a larger share. The high-purity ultra-fine quartz powder used as a filler for packaging materials has incomparable advantages.
Quartz powder requirements for electronic packaging
- High purity and ultrafine
Traditional application areas of quartz powder
| Application field | Application |
| Chemical industry | Amorphous silica powder, filler of sulfuric acid tower, raw material of water glass, raw material of silicon compound, etc. |
| Metallurgy | Raw materials or additives, fluxes, etc. of silicon aluminum alloy, ferrosilicon alloy, metal silicon, etc. |
| Glass | Glass products, flat glass, optical glass, glass fiber, etc. |
| Architecture | Artificial marble, concrete, cementitious materials, cement standard sand, etc. |
| Ceramics and refractory materials | High-silica bricks and ceramic blanks used in kilns, etc. |
| Rubber, plastic | Filler to improve wear resistance |
| Paint | Filler to improve weather resistance |
| Machinery | The main raw materials of foundry sand, sandblasting, sandpaper, gauze, etc. |
| Electronics | High-purity metallic silicon, optical fiber for communication, etc. |
High-purity ultra-fine quartz powder can improve the acid and heat performance, mechanical strength, dielectric properties and thermal conductivity of the packaging material; reduce the thermal expansion coefficient, water absorption rate, molding shrinkage rate and cost rate of the packaging material. High-purity ultra-fine quartz powder is widely used in the manufacture of electronic inks, optical fibers, advanced precision ceramics, precision grinding of optical devices and electronic components, etc. The most important of which is in the field of electronic packaging. Quartz powder for electronic packaging must be high-purity and ultra-fine. Generally, the purity of SiO2 is required to be above 99.99%, Fe2O3 is less than 5ppm, and the total amount of impurities is required to be less than 300ppm.
With the rapid development of the microelectronics industry, large-scale and ultra-large-scale integrated circuits have increasingly higher requirements for packing materials for packaging materials. Not only ultra-fine and high-purity, but also low radioactive element content is required, especially for particle shapes. Sphericalization requirements.
High-purity ultra-fine spherical quartz powder has the properties of low friction coefficient, low impurity, low stress, low expansion, high dielectric, high heat resistance, high humidity resistance, and high filling.
The surface area of the ball is the smallest, the isotropy is good, it is uniformly mixed with the resin to form a film, the amount of resin added is small, and the fluidity is the best. The higher the quartz powder filling rate, the smaller the thermal expansion coefficient of the molding compound, and the lower the thermal conductivity, the closer the thermal expansion coefficient of monocrystalline silicon is, and the better the performance of the electronic components produced therefrom.
The plastic molding compound made of spherical powder has the smallest stress concentration and the highest strength. When the stress concentration of the angular powder molding compound is 1, the stress of the spherical powder is only 0.6. Therefore, the spherical powder molding compound has a high yield when encapsulating integrated circuit chips. It is not easy to cause mechanical damage during transportation, installation and use.
The friction coefficient of spherical powder is small, and the wear on the mold is small, so that the service life of the mold is long. Can reduce costs and improve economic efficiency.
Preparation of High Purity Superfine Electronic Grade Spherical Quartz Powder
Experts show that as long as the purity can meet the requirements, it is best to use natural crystalline quartz as the raw material, with low cost and simpler process lines. Quartz raw materials include quartzite, vein quartz, quartz sandstone, powder quartz, and quartz sand.
Natural quartz minerals contain a large number of inclusions and cracks. The use of ultrafine pulverization technology can greatly reduce the number of cracks and defects. Combined with the purification process, the content of harmful impurities can be better reduced.
Thermal crushing first can greatly improve crushing efficiency, reduce equipment failure rate, and reduce crushing costs.
The requirement for grinding media is to choose less abrasion, high hardness, and a diameter between 1~5mm.
For ultrafine quartz powder, stirring mill, vibrating mill, and jet mill are often used.
- Processing technology
Quartz powder → magnetic separation → flotation → ultra-fine grinding → pickling → deacidification cleaning → filter press dehydration → drying → breaking up → finished product
The advantages of dry production of quartz powder are obvious: low comprehensive production cost, high output, and easy control of the process. However, the dust is too large and there is a crushing limit, it is difficult to produce micron-sized quartz powder. Therefore, the wet process is generally used when producing high-purity ultra-fine spherical quartz powder powder.
- Purification process
- Physical purification
Water washing and grading desliming, scrubbing, magnetic separation and flotation. But in order to obtain high-purity quartz powder, the quartz powder must be chemically purified.
- Chemical purification
Acid leaching: The principle is to use the insoluble acid, but the impurities can be dissolved in the acid, and the impurities in the quartz powder are removed by acid leaching to achieve the purpose of purification. Commonly used acids are hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid and oxalic acid.
- Sphericalization process
The research of China’s high-purity ultra-fine spherical quartz powder has entered the pilot stage, and has undergone three adjustments: AC high-frequency plasma fusion method, DC plasma fusion method, and arc method formed by carbon electrodes. The key to the technology is that the heating device requires a stable temperature field, an easy-to-adjust temperature range, and a clean heat source environment that will not cause secondary pollution to the quartz powder. There is currently no report on the industrialized production system.
Other commonly used silica high-temperature fusion spraying method, gas flame method, liquid phase control ethyl orthosilicate, silicon tetroxide hydrolysis method.
Status analysis and outlook
With the further development of the electronics industry, the fourth wave of development of electronic packaging technology is bound to usher in the system-in-package, which will lead to the sudden emergence of the spherical quartz powder market.
With the advancement of science and technology, especially the development of microelectronics technology, the demand for high-purity and ultra-fine electronic grade quartz powder has doubled, and its quality requirements have become higher and higher. Actively explore and promote the progress of quartz beneficiation and purification technology, and realize the low-cost, large-scale industrial production of refined quartz, high-purity and ultra-high-purity quartz, which is important for making up for the shortage of natural crystal resources and meeting the demand for high-purity ultra-fine quartz powder for high-tech use. The practical significance of.
Article source: China Powder Network