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AssigneeCatalysts & Chemicals Industries Co., Ltd.
InventorsHiroyasu Nishida, Yoshinori Wakamiya, Manabu Watanabe, Michio Komatsu
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The present invention provides a dispersion liquid of silica particles for polishing with a low content of Na ions and also with a content of ions other than Na ions in a prespecified range. This dispersion liquid is a dispersion liquid of silica particles in which the silica particles having the average particle diameter in the range from 5 to 300 nm is dispersed, and a content of Na ions in the silica particle is less than 100 ppm, while a contents of ions other than Na ions is in the range from 300 ppm to 2 weight %.
A dispersion liquid of silica particles for polishing with an average particle diameter in the range from 5 to 300 nm, wherein a content of Na ions in the silica particle is less than 100 ppm and a content of ions other than Na ions is in the range from 300 ppm to 2 weight %.
A method of producing a dispersion liquid of silica particles for polishing by adding an acidic silicic acid solution in a dispersion liquid of core particles for growing the core particles, wherein a content of Na ions (Ns) as defined by a number of Na ions per square meter of a surface area of the core particle is less than 50×1017 pieces/core particle's surface area(m2) and a content of ions other than Na ions (Nk) as defined by a number of ions other than Na ions in the core particle dispersion liquid per square meter of a surface area of the core particle is in the range from 5×1017 to 2000×1017 pieces/core particle's surface area(m2), and also wherein the ratio of (Nk/Ns) is 5 or more.
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