This project belongs to the field of new materials. The surface flatness requirements of integrated circuits and LED chip materials are extremely high. Generally, the surface roughness needs to be controlled at 1-3 Angstroms. Electronic grade silicon dioxide (SiO2) abrasives and polishing liquids are the key materials to achieve their atomic-level surfaces. The core technology and key preparation processes are completely monopolized by large foreign companies. With the support of major national projects and other plans, this project focuses on core technologies such as electronic-grade SiO2 abrasives and polishing solution preparation. The innovation points are as follows:

1. Invented a new method for preparing SiO2 ion exchange and surface modification. When manufacturing water glass, by controlling the concentration of anions in raw materials and fully dissolving metal elements, a new ion exchange method was invented to obtain high-purity and uniform SiO2 abrasive with Na and K contents less than 3ppm and Al and Fe contents less than 5ppm. The obtained SiO2 abrasive has obvious advantages in purity compared with similar technologies at home and abroad; A new stable nucleation and growth method was invented, and large-particle-size crystal cores of 5-30nm were obtained. On this basis, an efficient one-step synthesis method was used to achieve the production of colloidal SiO2 with large-particle-size of 60-150nm; its surface can be further modified to obtain a series of colloidal SiO2 stable at pH2-11.
2. Invented a series of sapphire polishing liquids that have high polishing efficiency and meet different process needs of manufacturers. The invention adopts the self-developed colloidal SiO2 nano-abrasive, optimizes the particle size grading ratio of the nano-abrasive, regulates the flow mechanical properties of multiple layers, accurately controls the chemical characteristics of surface hydroxyl groups and other groups, and simultaneously improves and balances the mechanical and chemical effects of the polishing solution. The mass production polishing rate is as high as 5-6 microns/hour, and the market share of LED chips in China exceeds 70%.
3. Invented aluminum alloy and stainless steel series metal polishing liquids with high polishing surface quality. The invention uses independently developed SiO2 nano-abrasive materials to design and select chelating agents with different components and structures that have significant expression of Al, Fe and other elements, inhibitors that can form oxide layers on the metal surface, and polyacrylic surfactants that can be adsorbed on the metal surface. By effectively controlling chemical reactions and enhancing polishing mechanical properties, the polishing rate is improved, and at the same time, the micro-defects on the metal surface such as scratches and orange peels are reduced.
4. Key processes and equipment for the industrial preparation of 10,000-ton ultra-pure SiO2. The invention breaks through key technologies such as water glass synthesis and exchange to reduce the concentration of anions and anions in the production of water glass and silicic acid, high-temperature ultrafiltration technology and uniform growth technology in the growth process of nanomaterials, and colloidal SiO2 surface ion modification production technology. It grasps the windows of key production parameters such as pH value, concentration, heating temperature, dropping rate and stirring rate, optimizes the process flow, realizes online monitoring and automatic regulation, and breaks the strict foreign technical blockade. A 10,000-ton ultra-pure SiO2 industrial production line with independent intellectual property rights has been built.
   This project has applied for 60 China invention patents and 1 PCT patent, of which 33 have been authorized, 53 papers have been published, 3 corporate standards have been formed, and 2 national new product certificates have been obtained. After expert identification and novelty search, this project "has achieved the mass production and industrialization of nano-SiO2 abrasive and phase change memory GST polishing solution","the SiO2 colloidal material of the invention has reached the international advanced level","the sapphire polishing solution and metal polishing solution are novel."
   Electronic-grade SiO2 nano-abrasive and polishing liquids have achieved industrialization at the level of 10,000 tons, becoming the only domestic supplier of IC polishing liquid abrasives. The polishing liquids developed have been used in more than 60 companies such as SMIC, Fuso, Orid, and Foxconn in Japan. Large-scale application has generated direct economic benefits of 100 million yuan. The project broke international monopoly, achieved a large proportion of imported products, greatly reduced the cost of key consumables in industries such as IC, semiconductor lighting and smartphones, and played an important role in improving the competitiveness of my country's industries. Only 6 of them achieved an added output value of 1.37 billion yuan using this invention. This project has greatly promoted the preparation level of new SiO2 nano materials in my country.