Dispersion liquid of silica particles for polishing, method of producing the same, and polishing agent
AssigneeCatalysts & Chemicals Industries Co., Ltd.
InventorsHiroyasu Nishida, Yoshinori Wakamiya, Manabu Watanabe, Michio Komatsu
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Abstract
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 %.
Claims5
A dispersion liquid for polishing comprising:
- silica particles with an average particle diameter in a range from 5 to 300 nm, said silica particles containing Na ions less than 100 ppm and at least one kind of ions selected from the group consisting of Li, K, Rb, Cs, NH4, Mg, Ca, Sr, Ba in a 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 a range from 5×1017 to 2000×1017 pieces/core particle's surface area(m2), and also wherein a ratio of (Nk/Ns) is 5 or more.
Dependencies are inferred from the claim text.