14 results about "Ammonium fluorosilicate" patented technology

The invention relates to the technical field of industrial solid waste resource utilization, and particularly discloses a fluorine-containing silicon slag recycling process which comprises five steps of fluorine-containing silicon slag raw material pretreatment, acid leaching fluorine extraction, ammonium fluosilicate preparation, nanometer silica gel purification and wastewater recycling. Fluorine in the fluorine-containing silicon slag is converted into ammonium fluosilicate solid to be recycled, fluorine in the fluorine-containing silicon slag is converted into sodium silicate to be manufactured into nano silica gel to be recycled, only feeding reaction is needed in the whole process, then filtering is conducted, the technological process is simple, and the treatment efficiency of the fluorine-containing silicon slag is improved. 0.3 ton of ammonium fluosilicate (the market price is 8000 yuan / ton) and 0.2 ton of nano silica gel (the market price is 15000 yuan / ton) can be produced from each ton of fluorine-containing silicon slag, and huge economic value can be brought to factories.

The invention discloses a method for modifying a nano-cluster Y molecular sieve, which comprises the following steps of: (a) controlling the sodium oxide content of the nano-cluster Y molecular sieve to be 2.0-4.5% through ion exchange treatment; (b) adopting an ammonium fluosilicate solution to carry out shallow dealumination and silicon supplementation on the nano-cluster Y molecular sieve obtained in the step (a), wherein the shallow dealumination and silicon supplementation means that the silica-alumina ratio of the nano-cluster Y molecular sieve after dealumination and silicon supplementation is controlled to be increased by 50-200% compared with that of the nano-cluster Y molecular sieve before treatment, and preferably, the silica-alumina ratio of the nano-cluster Y molecular sieve after dealumination and silicon supplementation is increased by 80-150%; (c) carrying out hydrothermal dealumination treatment on the material obtained in the step (b); and (d) carrying out acid treatment on the material subjected to hydro-thermal treatment to obtain the modified nano-cluster Y molecular sieve. Compared with a nano-cluster Y molecular sieve before treatment, the modified Y molecular sieve prepared by adopting the modification method not only keeps the nano-cluster shape, but also greatly improves the mesoporous content and the hydrothermal stability.

The invention belongs to the technical field of chemical product preparation, and particularly relates to a method for efficiently separating and purifying aluminum fluoride silicon slag and preparing white carbon black. Dropwise adding the ammonium fluoride solution into the aluminum fluoride silicon slag solution, then heating and stirring, then adding melamine and formaldehyde as dispersing agents, filtering after the reaction is finished, and filtering by adopting a carbon fiber membrane to obtain a filter cake which is high-purity aluminum fluoride and a filtrate which is an ammonium fluosilicate solution for later use; then slowly dripping the ammonium fluosilicate solution into the ammonia water solution, and maintaining the pH value of the reaction solution at 9.3-9.4; and after the reaction is finished, carrying out solid-liquid separation and drying to obtain the white carbon black. When the white carbon black is prepared, ammonia water is selected as a base solution, the white carbon black is ensured to be separated out under an alkaline condition, the purity of the prepared white carbon black is 99% or above, the specific surface area is larger than 300 m / g, the oil absorption value exceeds 250 mL / 100 g, and the fluorine ion concentration is lower than 50 ppm. The silicon slag used in the invention is derived from solid waste of aluminum fluoride prepared from fluosilicic acid, the cost is low, and the whole process is environment-friendly and is suitable for industrial-scale production and application.

This invention discloses a method for preparing ammonium fluorosilicate modified molecular sieves. The method includes the following steps: (1) contacting activated carbon with an aqueous solution of a fluorocarbon surfactant to modify it, thereby obtaining modified activated carbon; (2) mixing the modified activated carbon and molecular sieve obtained in step (1) with an ammonium fluorosilicate solution for reaction, and separating the reaction products to obtain waste activated carbon and modified molecular sieve precursors; (3) washing, drying, and calcining the modified molecular sieve precursors obtained in step (2) to obtain modified molecular sieves. The method has the advantages of simple operation, low cost, high fluoride removal efficiency, and high yield of modified molecular sieve products.

The invention provides a process for removing silicon nitride on the back surface of a silicon wafer, which comprises the following steps: providing a silicon wafer which comprises a substrate and a silicon waveguide arranged on the top surface of the substrate, and depositing a first silicon nitride layer and a second silicon nitride layer on the front surface and the back surface of the silicon wafer respectively through LPCVD (Low Pressure Chemical Vapor Deposition); forming a protective layer on the top surface of the first silicon nitride layer; performing plasma treatment on the second silicon nitride layer to convert the second silicon nitride layer into an ammonium fluosilicate layer; and removing the ammonium fluosilicate layer. According to the method, the removal time of the second silicon nitride layer can be effectively shortened, the problems that in a traditional process, when hot phosphoric acid is directly adopted for removing the second silicon nitride layer for a long time, liquid medicine is unstable and frequently replaced due to consumption of the liquid medicine, the liquid medicine is lost in the liquid replacement process, and consumed time is long are solved, the process is more controllable, and the production efficiency is improved. The purpose of removing the second silicon nitride layer on the back surface of the silicon wafer with high quality is achieved.

A film forming method includes: a preparation process of preparing a substrate having a surface from which a first film without containing silicon and a second film are exposed; a first film formation process of forming a self-assembled monolayer, which has a fluorine-containing functional group and inhibits formation of a third film containing silicon, on the first film; a second film formation process of forming the third film on the second film; a modification process of decomposing the self-assembled monolayer by plasma using a gas containing hydrogen and nitrogen while maintaining a temperature of the substrate to be 70 degrees C. or lower, so that a side portion of the third film, which is formed in a vicinity of the self-assembled monolayer, is modified into ammonium fluorosilicate by active species contained in the decomposed self-assembled monolayer; and a removal process of removing the ammonium fluorosilicate.

The application discloses a molecular sieve modification method, which comprises the following steps: (1) preparing silica microspheres loaded with sodium fluoroaluminate seeds: mixing silica microspheres with a modifier solution to perform a reaction, and then performing filtration, washing and drying treatment on a reaction product to obtain the silica microspheres loaded with the sodium fluoroaluminate seeds; and (2) preparing ammonium fluosilicate modified molecular sieves: mixing the silica microspheres loaded with the sodium fluoroaluminate seeds obtained in the step (1), molecular sieves and an ammonium fluosilicate solution to perform a reaction, and then performing separation, washing, drying and calcination on a reaction product to obtain the ammonium fluosilicate modified molecular sieves. The method can simultaneously achieve the purposes of efficiently removing fluorides and improving the yield of molecular sieve products.

The application relates to a method and equipment for in-situ cleaning of a substrate surface for epitaxial growth pretreatment, which continuously performs the following steps in a single process chamber: an etchant generation step of generating an etchant containing NH4F and NH4F.HF by reacting NF3 gas with NH3 gas in a plasma environment; an etching step of reacting the etchant with a silicon oxide layer on the substrate surface to generate solid ammonium fluorosilicate at a temperature of 25 DEG C to 40 DEG C; a sublimation removal step of heating the substrate to 150 DEG C to 200 DEG C to sublimate and decompose the solid ammonium fluorosilicate into gaseous products, and removing the gaseous products from the process chamber; wherein the duration of the sublimation removal step is 1.5 to 3 times the duration required for a single sublimation annealing. By synergistically optimizing the temperature of the etching step and the sublimation volatilization temperature and time of the sublimation removal step, an atomically clean substrate surface with extremely low impurity residue can be stably obtained.

A method for forming a semiconductor device can include providing a substrate having a patterned structure comprising semiconductor materials, where the patterned structure has a side profile including indentations, such as a patterned film stack, and where a spacer layer is conformally deposited over the patterned structure and within the indentations, reacting a surface of the spacer layer with a plasma-excited first etch gas to form a reacted layer on the spacer layer, wherein the plasma-excited first etch gas includes fluorine, hydrogen, and nitrogen, and removing at least part of the reacted layer by ion bombardment from exposure to a plasma-excited second etch gas. The spacer layer can be SiOCN. The reacted layer can be ammonium fluorosilicate. The first etch gas can contain SF6, H2, and N2, or NF3, H2, and N2. The reacting and removing can be done at room temperature in a same chamber.

The invention discloses a method for co-producing high-dispersion white carbon black and electronic-grade fluoride salt by using fluorine-containing silicon slag, which comprises a leaching conversion unit, a solid-liquid separation unit, a modified crystallization reaction unit, a secondary separation and washing unit, a drying and collecting unit and a mother liquor regeneration unit, the method has the advantages that the solid silicon slag is converted into the liquid ammonium fluosilicate solution through the leaching conversion unit, insoluble metal impurities such as iron, calcium and magnesium are thoroughly intercepted and separated by utilizing a solid-liquid phase state conversion mechanism and matching with the solid-liquid separation unit, the problems that the regenerated white carbon black is high in iron content and yellow in color are solved from the source, and the method is suitable for industrial production. The purity of the prepared product silicon dioxide can reach 99.5% or above; a process of combining in-situ modification and gradient ammonolysis is adopted, a dispersing agent is introduced in the initial stage of silicon dioxide crystal nucleus formation to construct a soft template, and hard agglomeration of primary particles is effectively blocked in cooperation with precise pH gradient control; the modified crystallization reaction adopts a three-section pH control method, so that the crystal quality is greatly improved.

The invention provides mesoporous silica and a preparation method thereof. The preparation method of the mesoporous silica comprises the following steps: obtaining a mixed system containing a first silicon source precursor, a soft template reagent and a second silicon source precursor; carrying out a sol-gel reaction on the double-silicon-source mixed system, carrying out solid-liquid separation, and collecting a solid phase to obtain a mesoporous silica precursor; wherein the first silicon source precursor comprises sodium silicate; the second silicon source precursor comprises sodium fluosilicate and / or ammonium fluosilicate. According to the method for preparing the mesoporous silicon dioxide, a double-silicon-source synergistic hydrolysis method is creatively used, the mesoporous silicon dioxide with a high specific surface area is prepared under the condition that an additional acid reagent or alkali reagent is not needed, and a brand new method is provided for synthesis of the mesoporous silicon dioxide.

The invention discloses a method for preparing high-silicon secondary pore zeolite by modifying natural STI zeolite. The method comprises the following steps: S1, taking an ammonium fluosilicate solution as a medium and microsphere zirconium oxide as a grinding material in a sand mill; s2, the NH4-STI powder crystal with the particle size being 13 microns and the SAR silicon-aluminum molar ratio being 6.0 is circularly ground and smashed for multiple times; and S3, simultaneously carrying out dealumination and silicon supplementation reaction to finally prepare the high-silicon STI zeolite microcrystalline material with the particle size of less than 1 micron and the SAR of more than or equal to 20. The preparation method has the advantages that the synthesis of a template agent is avoided, the raw material is natural ore, the cost is saved, the ammonium fluosilicate solution can be recycled, the discharge of waste liquid is reduced, the red zeolite resource can be efficiently developed, meanwhile, micropores keep shape selectivity and are suitable for macromolecule catalysis and adsorption, and the performance of the material in related applications is improved; and crystal grain nanocrystallization, silicon-aluminum ratio improvement and secondary pore structure construction are realized, the limitation of single function of traditional modification is broken through, and the material is optimized in multiple aspects.

The invention relates to a preparation method of white carbon black, and belongs to the technical field of chemical product preparation. The method for preparing the white carbon black with the high specific surface area from the fluorine-silicon slag comprises the following steps: carrying out ball-milling reaction on the hydrogen fluoride silicon slag and ammonium fluoride to obtain ammonium fluosilicate; ammonium fluosilicate is slowly added into ammonia water, and the pH value of the reaction liquid is always controlled to be 9.0-9.5; and after reaction, performing solid-liquid separation to obtain a white carbon black finished product. A ball milling mode is adopted, a reaction system can maintain weak acidity, silicon dioxide is prevented from being separated out, and then the fluorine-silicon slag is efficiently converted into ammonium fluosilicate. The purity of the obtained white carbon black is 99% or above, the yield is 95% or above, the F <-> concentration is smaller than 50 ppm, and the specific surface area of the white carbon black is gt; 300 m < 2 > / g, and the oil absorption value is gt; the yield of ammonium fluoride is more than 95% when the volume is 250mL / 100g. The raw material used for preparation is solid waste generated in the process of preparing hydrogen fluoride from fluosilicic acid, and the process is simple, environmentally friendly and suitable for industrial production.

A processing method of selectively etching an oxygen-containing film in a substrate having the oxygen-containing film and a nitrogen-containing film formed on a surface of the substrate, wherein the method includes: forming an ammonium fluorosilicate layer by selectively modifying the oxygen-containing film with respect to the nitrogen-containing film by using process gases including a fluorine-containing gas and a hydrazine-based gas; and removing the ammonium fluorosilicate layer by heating the substrate.