Polishing composition for semiconductor wafer, method for production thereof and polishing method
The present invention relates to a polishing composition for a substrate including a metal such as wiring, etc., formed on a semiconductor wafer, which can provide a high polishing rate without causing scratches on the wiring metal, a method of producing the polishing composition, and a polishing method. The polishing composition for a semiconductor wafer comprises an acid and an aqueous medium dispersion containing positively-charged silica particles having an amino group-containing silane coupling agent bonded on a surface thereof, the polishing composition having a pH of 2 to 6.
1. A polishing composition for a semiconductor wafer comprising:
an acid; and
an aqueous medium dispersion containing positively-charged silica particles having a surface on which an amino group-containing silane coupling agent is bonded,
the polishing composition having a pH of 2 to 5,
wherein the silica particles before coupling treatment have a specific surface area of 30 to 270 m 2 /g measured by a nitrogen adsorption BET method.
2. A polishing composition for a semiconductor wafer according to claim 1 , wherein the amino group-containing silane coupling agent is γ-aminopropyltrialkoxysilane.
3. A polishing composition for a semiconductor wafer according to claim 1 , wherein the acid is an organic acid having a pKa that is a logarithm of a reciprocal of acid dissociation constant of 3 to 5 at 25° C.
4. A polishing composition for a semiconductor wafer according to claim 3 , wherein the organic acid is acetic acid or malic acid.
5. A polishing composition for a semiconductor wafer according to claim 1 , wherein an amount of the amino group-containing silane coupling agent is in the range of 0.005 to 0.015 mmol/m 2 based on total surface area of the silica particles before coupling treatment.
6. A method of producing a polishing composition for a semiconductor wafer, comprising binding an amino group-containing silane coupling agent on a surface of silica particles in an acidic water dispersion medium having a pH adjusted to 2 to 4.0 to produce an aqueous medium dispersion containing positively-charged silica particles, wherein the silica particles before coupling treatment have a specific surface area of 30 to 270 m 2 /g measured by a nitrogen adsorption BET method.
7. A polishing method comprising:
utilizing the polishing composition according to claim 1 to polish a surface or edge of a semiconductor wafer.