Cleaning agent for semiconductor substrates and method for processing semiconductor substrate surface
View Patent ↗A cleaning agent is provided for a semiconductor substrate superior in corrosion resistance of a tungsten wiring or a tungsten alloy wiring, and superior in removal property of polishing fines (particle) such as silica or alumina, remaining at surface of the semiconductor substrate, in particular, at surface of a silicon oxide film such as a TEOS film, after a chemical mechanical polishing process; and a method for processing a semiconductor substrate surface. A cleaning agent for a semiconductor substrate is to be used in a post process of a chemical mechanical polishing process of the semiconductor substrate having a tungsten wiring or a tungsten alloy wiring, and a silicon oxide film, comprising (A) a phosphonic acid-based chelating agent, (B) a primary or secondary monoamine having at least one alkyl group or hydroxyalkyl group in a molecule and (C) water, wherein a pH is over 6 and below 7.
1. A method for processing a semiconductor substrate surface, comprising:
a process for treating a surface of a semiconductor substrate having a tungsten wiring or a tungsten alloy wiring, and a silicon oxide film, by chemical mechanical polishing; and
a process for cleaning the semiconductor substrate after the process by the chemical mechanical polishing, with a cleaning agent for a semiconductor substrate comprising (A) a phosphonic acid-based chelating agent, (B) a primary or secondary monoamine having at least one alkyl group or hydroxyalkyl group in a molecule represented by the general formula [6] or [7],
wherein R 10 and R 11 each independently represent a monohydroxyalkyl group having 1 to 3 carbon atoms; and R 12 represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a monohydroxyalkyl group having 1 to 3 carbon atoms,
wherein R 13 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; and R 14 represents a dihydroxyalkyl group having 1 to 3 carbon atoms, and (C) water, wherein a pH of the cleaning agent is over 6 and below 7.
2. The method according to claim 1 , wherein (B) the primary or secondary monoamine having at least one alkyl group or hydroxyalkyl group in a molecule represented by the general formula [6] or [7] is 2-amino-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-hydroxymethyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, 3-amino-1,2-propanediol or 3-methylamino-1,2-propanediol.
3. The method according to claim 1 , wherein the pH is 6.2 to 6.8.
4. The method according to claim 1 , wherein (A) the phosphonic acid-based chelating agent is the one represented by the general formula [1], [2] or [3]:
(wherein X represents a hydrogen atom or a hydroxyl group; and R 1 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms);
(wherein Q represents a hydrogen atom or —R 3 —PO 3 H 2 ; R 2 and R 3 each independently represent an alkylene group; and Y represents a hydrogen atom, —R 3 —PO 3 H 2 or a group represented by the general formula [4]),
(wherein Q and R 3 are the same as described above);
(wherein R 4 and R 5 each independently represent an alkylene group having 1 to 4 carbon atoms; “n” represents an integer of 1 to 4; and at least 4 groups of Z 1 to Z 4 and n moieties of Z 5 represent an alkyl group having a phosphonic acid group, and remaining groups represent an alkyl group).
5. The method according to claim 1 , wherein (A) the phosphonic acid-based chelating agent is 1-hydroxyethylidene-1,1′-diphosphonic acid, nitrilotris(methylenephosphonic acid), ethylenediamine tetra(methylenephosphonic acid) or diethylenetriamine penta(methylenephosphonic acid).
6. The method according to claim 1 , wherein the semiconductor substrate is the one having further a silicon nitride film.
7. The method according to claim 1 , wherein (B) the primary or secondary monoamine having at least one alkyl group or hydroxyalkyl group in a molecule represented by the general formula [6] or [7] is 2-amino-2-hydroxymethyl-1,3-propanediol.