Polishing agent, storage solution for polishing agent and polishing method

1. A polishing agent for chemomechanically polishing a base having a carbon-based material and an insulating material to remove at least a part of the carbon-based material,

the carbon-based material having a carbon content of 60 to 95 atm% as measured by X-ray photoelectron spectroscopy,

the polishing agent comprising:

an abrasive grain comprising silica;

an allylamine-based polymer; and

water, wherein

a mass ratio of a content of the allylamine-based polymer with respect to a content of the abrasive grain is 0.002 to 0.400, and

the abrasive grain has a positive charge in the polishing agent.

2. The polishing agent according to claim 1 , wherein the allylamine-based polymer has at least one selected from the group consisting of a structural unit represented by the following general formula (I), a structural unit represented by the following general formula (II), a structural unit represented by the following general formula (III), a structural unit represented by the following general formula (IV), and a structural unit represented by the following general formula (V)

[In formulae, R 11 , R 12 , R 2 and R 3 each independently represent a hydrogen atom, an alkyl group or an aralkyl group, and the amino group and the nitrogen-containing ring each independently optionally form an acid addition salt]

[In formulae, R 41 and R 42 each independently represent an alkyl group or an aralkyl group, R 51 and R 52 each independently represent an alkyl group or an aralkyl group, and D— represents a monovalent anion].

3. The polishing agent according to claim 1 , wherein the silica is colloidal silica.

4. The polishing agent according to claim 1 , further comprising an organic solvent.

5. The polishing agent according to claim 1 , having a pH of 1.0 to 8.0.

6. The polishing agent according to claim 1 , further comprising an acid component.

7. The polishing agent according to claim 1 , wherein a polishing rate ratio of the carbon-based material with respect to the insulating material is 50 or more.

8. The polishing agent according to claim 1 , wherein the polishing agent is stored in a form of a multi-pack polishing agent comprising:

a first liquid comprising the abrasive grain and water, and

a second liquid comprising the allylamine-based polymer and water.

9. A stock solution of a polishing agent for obtaining the polishing agent according to claim 1 , the stock solution being diluted with water to obtain the polishing agent.

10. A polishing method comprising:

a step of providing a base having a carbon-based material and an insulating material; and

a polishing step of chemomechanically polishing the base using the polishing agent according to claim 1 to remove at least a part of the carbon-based material, wherein

the carbon-based material has a carbon content of 60 to 95 atm% as measured by X-ray photoelectron spectroscopy.

11. A polishing method comprising:

a step of providing a base having a carbon-based material and an insulating material;

a step of diluting the stock solution of a polishing agent according to claim 9 with water to obtain the polishing agent; and

a polishing step of chemomechanically polishing the base using the polishing agent to remove at least a part of the carbon-based material, wherein

the carbon-based material has a carbon content of 60 to 95 atm% as measured by X-ray photoelectron spectroscopy.

12. The polishing method according to claim 10 , wherein in the polishing step, polishing is stopped when the insulating material is exposed.