Preparation method and application of silica sol with irregular shape

Abstract

The invention provides a preparation method of silica sol with an irregular shape. The silica sol with the irregular shape is silicon dioxide sol particles with irregular shapes, in a state of the aggregation growth of 2-3 particles, and when the silicon dioxide sol particles are in linear shapes or bent shapes, the long axes of each of the particle diameters of the particles subjected to aggregation growth can achieve 30-60 nm. The preparation method comprises the following steps: with spherical silica sol with a concentration of 2-3.5% and a small particle diameter of 10 nm or 15 nm as mother liquor, adding the mother liquor in a reactor; adding a soluble divalent anion salt solution or trivalent cation salt solution in the mother liquor, and uniformly stirring; then adjusting the pH value to 9-10 by inorganic base with a concentration of 5% or 10%; stirring and heating to boil; then dripping active silicic acid in the reaction system, meanwhile, dripping an inorganic base solution to keep the pH value of the reaction system to be in a range from 9 to 10; and after the dripping is concluded, cooling the reaction product to a room temperature. The preparation method provided by the invention has the technical benefits of being simple in process and good in colloidal stability.

Description

technical field [0001] The invention relates to a method for preparing silica sol with an irregular shape and an application thereof, which belongs to the field of chemical mechanical polishing and can be used for polishing silicon wafers, sapphires and hard disks. Background technique [0002] In chemical mechanical polishing, more and more silica sols are used as abrasives for mechanical grinding. At present, large particle spherical silica sols are generally used in polishing liquid products. In order to further increase the polishing rate of silica sol, people have studied the preparation method of silica sol with irregular shape. [0003] There are relatively few reports on the preparation of irregular silica sol in domestic and foreign research materials, and most of them use the method of organosilane hydrolysis to prepare cocoon-shaped or linear silica sol, but it is not suitable for chemical mechanical polishing. There is also a small amount of information on the p...

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Problems solved by technology

[0003] There are relatively few reports on the preparation of irregular silica sols in domestic and foreign research materials. Most of them use organosilane hydrolysis to prepare cocoon-shaped or linear silica sols, but they are not suitable for chemical mechanical polishing.

There is also a small amount of information on the preparation of irregular silica sols by ion exchange and organic bases to adjust pH, such as: US20080038996A1, US20100163786A1, US20090223136A1, etc., but there is a lack of description of its application in chemical mechanical polishing

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