Silicon dioxide particle dispersion for grinding and grinding composition

Abstract

The purpose of this invention is to provide a silicon dioxide particle dispersion, a polishing composition, and a polishing method for use in CMP polishing of device wafers, which maintains a high polishing speed while suppressing the generation of scratches. A silicon dioxide particle dispersion for grinding, comprising silicon dioxide particles and water, wherein the number of spherical foreign objects with an equivalent circular diameter of 0.48 μm or more and a shape factor SF1LP of less than 1.50 as measured by either Method A or Method B is 15 or fewer. Method A involves adding pure water to the aforementioned dispersion to dilute the silicon dioxide concentration to 0.1% by mass. 30 g of the resulting diluted solution is filtered through a filter with an absolute pore size of 0.4 μm (filter area 1.8 cm²). The filter is then magnified to 5000x field of view (area 448 μm²) using a scanning electron microscope (SEM), and 20 fields of view are observed. The equivalent circular diameter of the aforementioned spherical foreign objects is calculated using image analysis. Furthermore, the equivalent circular diameter of the spherical foreign object is determined by connecting any two points on the outline of the spherical foreign object relative to its projected area SLP. The shape factor SF1LP is defined as the ratio of the length of the longest straight line connecting any two points on the outline of the spherical foreign object to the area of ​​the circle with diameter LLP (LLP²×π / 4) / SLP. Method B involves adding pure water to the aforementioned dispersion to dilute the silica concentration to 0.03% by mass. 30g of the resulting diluted solution is filtered through a filter with an absolute pore size of 0.4μm (filter area 1.8cm²). The filter is then magnified to 5000x field of view (area 448μm²) using a scanning electron microscope (SEM), and 67 fields of view are observed. The equivalent circular diameter of the aforementioned spherical foreign object is calculated using image analysis. Furthermore, the shape factor SF1LP is defined as the ratio of the length of the longest straight line connecting any two points on the outline of the spherical foreign object to the area of ​​the circle with diameter LLP (LLP²×π / 4) / SLP, relative to the projected area SLP of the aforementioned spherical foreign object.

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