Polishing composition, polishing method, and method for producing semiconductor substrate
A polishing composition according to the present invention contains zirconia particles, a selectivity improver for improving a ratio of a polishing speed for an organic material (b) to a polishing speed for a material (a) having a metal-nitrogen bond, and a dispersing medium, wherein in a particle size distribution of the zirconia particles obtained by a laser diffraction/scattering method, a diameter (D50) of the particles when a cumulative volume of the particles from a fine particle side reaches 50% of a total volume of the particles is 5 nm or more and 150 nm or less, and a pH of the polishing composition is less than 7.
1 . A polishing composition comprising:
colloidal zirconia particles doped with yttrium or an oxide thereof;
a selectivity improver for improving a ratio of a polishing speed for an organic material (b) to a polishing speed for a material (a) having a metal-nitrogen bond; and
a dispersing medium,
wherein:
in a particle size distribution of the colloidal zirconia particles obtained by a laser diffraction/scattering method, a diameter (D50) of the colloidal zirconia particles when a cumulative volume of the colloidal zirconia particles from a fine particle side reaches 50% of a total volume of the particles is 5 nm or more and 150 nm or less;
the selectivity improver comprises a non-aromatic bridged cyclic compound having an organic acid group or a salt group thereof;
a content of the non-aromatic bridged cyclic compound having an organic acid group or a salt group thereof is 0.001% by mass or more and 10% by mass or less, based on the total mass of the polishing composition; and
a pH of the polishing composition is less than 7.
2 . The polishing composition according to claim 1 , wherein the non-aromatic bridged cyclic compound having an organic acid group or a salt group thereof is a compound represented by the following general formula 1:
wherein:
Z 1 is CR 1 R 1 ′, C═O, or O;
Z 2 is CR 2 R 2 ′, C═O, or O;
Z 3 is CR 3 R 3 ′, C═O, or O;
Z 4 is CR 4 R 4 ′, C═O, or O;
R 1 , R 1 ′, R 2 , R 2 ′, R 3 , R 3 ′, R 4 , R 4 ′, R 5 , R 6 , R 7 , and R 8 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted polyoxyalkylene group, or an organic acid group or a salt group thereof;
when at least one of R 1 , R 1 ′, R 2 , R 2 ′, R 3 , R 3 ′, R 4 , R 4 ′, R 5 , R 6 , R 7 , and R 8 is a substituted group, it is substituted with a substituent selected among a deuterium atom, a halogen atom, an unsubstituted alkyl group, an unsubstituted alkenyl group, an unsubstituted alkynyl group, an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or a salt group thereof; and
at least one of R 1 , R 1 ′, R 2 , R 2 ′, R 3 , R 3 ′, R 4 , R 4 ′, R 5 , R 6 , R 7 , and R 8 contains an organic acid group or a salt group thereof.
3 . The polishing composition according to claim 2 , wherein the compound represented by general formula 1 is 10-camphorsulfonic acid.
4 . The polishing composition according to claim 1 , which is used for polishing an object to be polished comprising the material (a) having a metal-nitrogen bond and the organic material (b).
5 . The polishing composition according to claim 1 , wherein the selectivity improver further comprises a water-soluble polymer having a polar group.
6 . The polishing composition according to claim 5 , wherein the water-soluble polymer having a polar group comprises at least one selected from the group consisting of polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylamide.
7 . The polishing composition according to claim 6 , wherein the water-soluble polymer having a polar group comprises at least one selected from the group consisting of polyvinyl alcohol and polyvinylpyrrolidone.
8 . The polishing composition according to claim 7 , wherein the water-soluble polymer having a polar group comprises polyvinylpyrrolidone.
9 . The polishing composition according to claim 1 , wherein the selectivity improver further comprises an anionic surfactant.
10 . The polishing composition according to claim 9 , wherein the anionic surfactant comprises a sulfonic acid-type anionic surfactant or a sulfuric acid ester-type anionic surfactant.
11 . The polishing composition according to claim 10 , wherein the anionic surfactant is a sulfonic acid-type anionic surfactant selected from the group consisting of sodium lauryl sulfoacetate, sodium 1-propanesulfonate, sodium 1-butanesulfonate, sodium 1-pentanesulfonate, sodium 1-hexanesulfonate, sodium 1-heptanesulfonate, sodium 1-octanesulfonate, sodium 1-decanesulfonate, sodium 1-dodecanesulfonate, sodium toluenesulfonate, sodium cumenesulfonate, sodium naphthalenesulfonate, disodium naphthalenedisulfonate, trisodium naphthalenetrisulfonate, sodium alpha-olefinsulfonate, and sodium dodecylbenzenesulfonate, or a sulfuric acid ester-type anionic surfactant selected from the group consisting of sodium lauryl sulfate, sodium myristyl sulfate, sodium laureth sulfate (sodium polyoxyethylene lauryl ether sulfate), sodium cetyl sulfate, sodium cocoglyceryl sulfate (sodium hydrogenated coconut oil fatty acid glyceryl sulfate), triethanolamine lauryl sulfate, ammonium lauryl sulfate, and triethanolamine laureth sulfate.
12 . The polishing composition according to claim 10 , wherein the anionic surfactant is sodium 1-hexanesulfonate or ammonium lauryl sulfate.
13 . The polishing composition according to claim 1 , wherein the selectivity improver further contains at least one of a water-soluble polymer having a polar group and at least one of an anionic surfactant.
14 . The polishing composition according to claim 13 , wherein the water-soluble polymer having a polar group is polyvinyl alcohol or polyvinylpyrrolidone; and the anionic surfactant is a sulfonic acid-type anionic surfactant or a sulfuric acid ester-type anionic surfactant.
15 . The polishing composition according to claim 1 , wherein the content of the non-aromatic bridged cyclic compound having an organic acid group or a salt group thereof is 0.005% by mass or more and 0.3% by mass or less, based on the total mass of the polishing composition.
16 . The polishing composition according to claim 1 , wherein the content of the non-aromatic bridged cyclic compound having an organic acid group or a salt group thereof is 0.01% by mass or more and 0.1% by mass or less, based on the total mass of the polishing composition.
17 . The polishing composition according to claim 1 , wherein the diameter (D50) of the colloidal zirconia particles when a cumulative volume of the colloidal zirconia particles from a fine particle side reaches 50% of a total volume of the particles is 90 nm or less.
18 . The polishing composition according to claim 1 , wherein a content of the colloidal zirconia particles is 0.01% by mass or more and less than 1% by mass, based on the total mass of the polishing composition.
19 . A polishing method comprising a step of polishing an object to be polished comprising the material (a) having a metal-nitrogen bond and the organic material (b) using the polishing composition according to claim 1 .
20 . A method for producing a semiconductor substrate, comprising a step of polishing a semiconductor substrate comprising the material (a) having a metal-nitrogen bond and the organic material (b) by the polishing method according to claim 19 .