Post-CMP semiconductor cleaning composition comprising an amine/alkanolamine mixture
There is provided a method of cleaning semiconductor substrates that is excellent in cleaning performance with respect to semiconductor substrates having undergone a chemical mechanical polishing process and corrosion prevention performance with respect to metal films. This method includes a cleaning step of cleaning a semiconductor substrate having undergone the CMP using a cleaning liquid. The cleaning liquid shows alkaline properties and contains: a component A that is at least one selected from the group consisting of a primary amine, a secondary amine, and a tertiary amine, provided that a compound represented by a specific formula (a) is excluded; and a component B that is a compound represented by the specific formula (a). The mass ratio of the component B content to the component A content is not more than 0.01. The cleaning liquid applied to the semiconductor substrate has a temperature of not lower than 30° C.
1. A method of cleaning semiconductor substrates, the method comprising a cleaning step of cleaning a semiconductor substrate having undergone a chemical mechanical polishing process using a cleaning liquid,
wherein the pH of the cleaning liquid is not less than 10.5 at 25° C. and the cleaning liquid contains:
a component A that is at least one selected from the group consisting of a primary amine, a secondary amine, a tertiary amine, and their salts, provided that a compound represented by Formula (a) is excluded; and
a component B that is a compound represented by Formula (a),
wherein a mass ratio of a content of the component B to a content of the component A is not more than 0.01, and
wherein the cleaning liquid applied to the semiconductor substrate has a temperature of not lower than 30° C.,
NH x R (3-x) (a)
where R represents an alkyl group having 1 to 3 carbon atoms that is composed of hydrogen atoms and a carbon atom or atoms, and x represents an integer of 0 to 3.
2. The method according to claim 1 , wherein the component A contains an amino alcohol.
3. The method according to claim 2 , wherein a first acidity constant of a conjugated acid of the amino alcohol is not less than 7.0.
4. The method according to claim 2 , wherein the amino alcohol has a primary amino group.
5. The method according to claim 2 , wherein the amino alcohol has a quaternary carbon atom at an α position of an amino group.
6. The method according to claim 2 , wherein the amino alcohol is 2-amino-2-methyl-1-propanol.
7. The method according to claim 1 , wherein the cleaning liquid contains two or more compounds included in the component A.
8. The method according to claim 1 , wherein the cleaning liquid further contains a chelating agent.
9. The method according to claim 1 , wherein the cleaning liquid further contains a reducing agent.
10. The method according to claim 1 , wherein the cleaning liquid further contains two or more reducing agents.
11. The method according to claim 1 , wherein the cleaning liquid further contains a quaternary ammonium compound.
12. The method according to claim 11 , wherein the quaternary ammonium compound has an asymmetric structure.
13. The method according to claim 1 , wherein the cleaning liquid further contains two or more quaternary ammonium compounds.
14. The method according to claim 1 , wherein the cleaning liquid further contains a surfactant.
15. The method according to claim 1 , wherein the cleaning liquid further contains two or more surfactants.
16. The method according to claim 1 , wherein the semiconductor substrate has metal-containing matter containing at least one metal selected from the group consisting of cobalt, titanium, tantalum, ruthenium, and tungsten.
17. The method according to claim 1 , wherein an amount of supply of the cleaning liquid applied to the semiconductor substrate is 500 to 2000 mL/min.
18. The method according to claim 1 , wherein the cleaning step comprises brush scrubbing cleaning.
19. The method according to claim 1 , wherein a cleaning time in the cleaning step is 10 to 120 seconds.
20. The method according to claim 1 , further comprising a rinsing step of rinsing the semiconductor substrate with water after the cleaning step.
21. The method according to claim 1 , wherein a content of the component A is 0.05 to 15 mass % based on the total mass of the cleaning liquid, and a content of the component B is 0.00001 to 0.1 mass % based on the total mass of the cleaning liquid.