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CN-122010123-A - Spherical silica particles, silica sol containing spherical silica particles and application of spherical silica particles in polishing solution

CN122010123ACN 122010123 ACN122010123 ACN 122010123ACN-122010123-A

Abstract

The application discloses spherical silica particles, silica sol containing the spherical silica particles and application of the spherical silica particles in polishing solution. The spherical silica particles are characterized in that the average particle size of the spherical silica particles is selected from any value within the range of 20-200 nm, and the polydispersity index PDI of the particle size of the spherical silica particles is less than or equal to 0.10. The spherical silicon dioxide particles have the characteristics of larger particle size, uniform distribution and lower metal content. By introducing amino and sulfonic acid groups to the surface of the nanoparticles during the preparation process, silica sols stable under acidic conditions are obtained. In the preparation method, only instruments and equipment which do not contain metal elements are used, so that metal ion pollution is avoided. The acidic chemical mechanical polishing solution prepared from the spherical silicon dioxide particles can improve the polishing rate and avoid the pollution of metal ions to the wafer, thereby improving the chemical mechanical polishing efficiency.

Inventors

  • REN GAOYUAN
  • LIU XIANGYU
  • WANG SHUDONG

Assignees

  • 中国科学院大连化学物理研究所

Dates

Publication Date
20260512
Application Date
20251226

Claims (10)

  1. 1. The spherical silica particles are characterized in that the average particle size of the spherical silica particles is selected from any value in the range of 20-200 nm, and the polydispersity index PDI of the particle size of the spherical silica particles is less than or equal to 0.10.
  2. 2. The spherical silica particles according to claim 1, wherein the average particle diameter of the spherical silica particles is selected from any value in the range of 60 to 120nm, and the polydispersity index of the particle diameter of the spherical silica particles is 0.01≤pdi≤0.10.
  3. 3. Silica sol comprising spherical silica particles according to claim 1 or 2; the mass percentage of the spherical silicon dioxide particles in the silica sol is 1-10%.
  4. 4. A method of preparing a silica sol as claimed in claim 3, comprising the steps of: a) Adding the solution containing the organosilane into the solution containing the organic amine to obtain a mixture; b) And (3) aging, centrifugally separating and washing the mixture, and adjusting the pH value to be acidic to obtain the silica sol.
  5. 5. The method according to claim 4, wherein the solution containing the organic amine in step a) consists of the organic amine, an alcohol solvent and water; the organic amine is selected from at least one of alcohol amine compounds; The pH value of the solution containing the organic amine is 9.5-12.5 under 298K; preferably, the organic amine is at least one selected from ethanolamine, 1, 2-propanediol amine, 1, 3-propanediol amine, diethanolamine, triethanolamine and isopropanolamine; Preferably, the alcohol solvent is at least one selected from methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-butanol and tert-butanol.
  6. 6. The method of claim 4, wherein the organosilane-containing solution is an anhydrous alcoholic solution of organosilane; The organosilane is at least one of tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, 3-aminopropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane; Preferably, the organosilane is a composition of 3-aminopropyl trimethoxysilane and/or 3-mercaptopropyl trimethoxysilane and at least one of tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane; Preferably, the concentration of the organosilane in the solution containing the organosilane is 1 mol/L-10 mol/L.
  7. 7. The method according to claim 4, wherein step a) is to stir the solution containing the organic amine at 15-65 ℃ for at least 30min; The dripping time is 30-600 min; the stirring speed is 200-1000 rpm; the volume ratio of the solution containing organosilane to the solution containing organic amine is 0.05-0.5:1.
  8. 8. The method according to claim 4, wherein the aging temperature of the aging in step b) is 15-65 ℃ and the aging time is 2-48 h; The washing is to add deionized ultrasonic washing to the gel obtained by centrifugal separation and then centrifugally separate.
  9. 9. The method according to claim 6, wherein when the organosilane contains 3-mercaptopropyl trimethoxysilane, the step between centrifugation and washing in step b) further comprises: adding hydrogen peroxide and heating and refluxing for at least 6 hours.
  10. 10. A polishing liquid comprising at least one of spherical silica particles according to claim 1 or 2, a silica sol according to claim 3, and a silica sol produced by the method according to any one of claims 4 to 9.

Description

Spherical silica particles, silica sol containing spherical silica particles and application of spherical silica particles in polishing solution Technical Field The application relates to spherical silica particles, silica sol containing the spherical silica particles and application of the spherical silica particles in polishing solution, and belongs to the technical field of materials. Background Modern semiconductor processing technology has evolved to enable very large scale integrated circuits to be scaled down, with the density of devices and metal lines on the wafer increasing. In this way, the requirement for global planarization of wafers is also increasing. Chemical Mechanical Polishing (CMP) was first initiated in the twentieth century 80 as the only means of global planarization of a wafer, the basic principle being to use a combination of chemical etching and mechanical friction to remove material from the wafer to achieve global planarization. The method comprises the steps of fixing a wafer, pressing the wafer on a polyurethane polishing pad, injecting polishing slurry on the polishing pad, and simultaneously rotating the wafer and the polishing pad in the same direction, so that the wafer and the polishing pad are rubbed to remove substances. During this process, the nanoparticles in the polishing slurry contact and interact with the wafer to soften the wafer surface, and then physically and mechanically interact with the wafer to remove the softened layer. Global planarization is thus repeatedly achieved. After the devices and circuits of each layer of the VLSI are deposited on the wafer surface, planarization is required before subsequent photolithography, deposition, and etching processes can be performed. Thus, chemical mechanical polishing is one of the keys of the chip manufacturing industry. In theory, chemical mechanical polishing results in a scratch-free polished flat surface, and if a polishing slurry uses abrasive particles of high hardness, although the material removal rate is increased (Material Removing Rate), scratches remain on the material surface, and if softer abrasive particles are used, the material removal rate is decreased and the time consuming chemical mechanical polishing process is increased. The amorphous silicon oxide nano particles have softer hardness, so that scratches formed on the surface of the wafer during the chemical mechanical polishing process can be well controlled. Meanwhile, the hydroxyl groups on the surfaces of the silicon dioxide nano particles react with materials chemically in the polishing process, so that the rate of removing substances from the surface of the wafer is increased, and the polishing time is saved. Therefore, silicon oxide nanoparticles are widely used in the industry as slurry particles for wafer polishing. Silica nanoparticles can be obtained from the gaseous process (reaction of silicon chloride with water vapor), the water glass process (sodium silicate solution over cation exchange resin) and the St-ber process (hydrolytic condensation of organosilanes under the action of ammonia). The silicon oxide nano particles with narrow particle size distribution and uniform shape can be obtained by a water glass method, but partial metal ions can remain in the silicon oxide nano particles to influence the cleaning link after polishing. Meanwhile, the production process is troublesome, the time consumption is more and the control is difficult, so the nano silicon oxide particles obtained by the St and the ber method are used as nano particles for chemical mechanical polishing; The silica nanoparticles can be dispersed in water to form a sol which is relatively stable under alkaline conditions and can be stored for a long period of time without changing the basic physicochemical form. Silica sol is easy to agglomerate and even sink under acidic conditions, and part of the product can only be stored for several hours for stabilization and then is subject to sink. The silicon oxide nano particles are partially formed by the phenomenon that the surfaces of the silicon oxide nano particles almost have hydroxyl groups, the hydroxyl groups can ionize protons under alkaline conditions and carry negative electricity to form electric double layers on the surfaces of the nano particles, so that repulsive force is formed among the particles to form sol stably, the hydroxyl groups can not ionize protons under acidic conditions, the electric double layers can not be formed, electrostatic repulsive force is not generated among the particles, and coagulation is easy to cause. Disclosure of Invention In order to solve the technical problems, the application introduces new chemical groups, such as amino groups or sulfonic groups, to the surfaces of nano silicon oxide particles, so that the particles can still have charges under the acidic condition to form an electric double layer, thereby ensuring that the sol formed by the particles and water can s