Aqueous phosphoric acid compositions for cleaning semiconductor devices

• US 20040137736A1
• Filed: 10/21/2003
• Published: 07/15/2004
• Est. Priority Date: 10/22/2002
• Status: Active Grant

• Current Assignee: EKC Technology, Inc (DuPont de Nemours, Inc.)
• Original Assignee: EKC Technology, Inc (DuPont de Nemours, Inc.)
• Inventors: Daviot, Jerome, Holmes, Douglas, Reid, Christopher
• Granted Patent: US 7,235,188 B2
• Time in Patent Office: Days
• US Class Current: 438/690
• CPC Class Codes: C11D 2111/22 Electronic devices, e.g. PCBs or semiconductors
• CPC Class Codes: C11D 7/06 Hydroxides
• CPC Class Codes: C11D 7/08 Acids
• CPC Class Codes: C11D 7/3218 Alkanolamines or alkanolimines
• CPC Class Codes: C11D 7/3227 Ethers thereof
• CPC Class Codes: C11D 7/3281 Heterocyclic compounds
• CPC Class Codes: H01L 21/02071 the processing being a delineation, e.g. RIE, of conductive layers

Abstract

The present invention relates to dilute aqueous solutions containing phosphoric acid and methods for cleaning plasma etch residue from semiconductor substrates including such dilute aqueous solutions. The solution according to the invention may advantageous contain an alkaline compound, one or more other acid compounds, and/or a fluoride-containing compound and may optionally contain additional components such as organic solvents, chelating agents, amines, and/or surfactants.

Claims

1. An aqueous semiconductor cleaning solution comprising:

at least about 75% by weight water;

from about 0.5% to about 10% by weight phosphoric acid;

at least one alkaline compound selected from the group consisting of;

a quaternary ammonium hydroxide;

a hydroxylamine derivative having the structural formula;

wherein R₃ is hydrogen or a linear, branched, or cyclic hydrocarbon containing from 1 to 7 carbon atoms; and

wherein X and Y are, independently, hydrogen or a linear, branched, or cyclic hydrocarbon containing from 1 to 7 carbon atoms, or wherein X and Y are linked together form a nitrogen-containing heterocyclic C₄-C₇ ring; and

a mixture thereof; and

optionally one or more other acid compounds, one or more fluoride-containing compounds, and/or one or more alkanolamines having the structural formula;

wherein R₁, R₁′

, R₂, R₂′

, and R₃ are, independently in each case, hydrogen or a linear, branched, or cyclic hydrocarbon containing from 1 to 7 carbon atoms;

wherein Z is a group having the formula -(-Q-CR₁R₁′

-CR₂R₂′

-)_m-, such that m is a whole number from 0 to 3 (i.e., when m=0, there is no atom between the -CR₂ R₂′

- group and the -OR₃ group in the formula above), R₁, R₁′

, R₂, and R₂′

+0'"'"'MAY be independently defined in each repeat unit, if m>

1, within the parameters set forth for these moieties above, and Q may be independently defined in each repeat unit, if m>

1, each Q being independently either -O- or -NR₃-; and

wherein X and Y are, independently in each case, hydrogen, a C₁-C₇ linear, branched, or cyclic hydrocarbon, or a group having the formula -CR₁R₁′

-CR₂ R₂′

-Z-F, with F being either -O-R₃ or -NR₃R₄, where R₄ is defined similarly to R₁, R₁′

, R₂, R₂′

, and R₃ above and with Z, R₁, R₁′

, R₂, R₂′

, and R₃ defined as above, or wherein X and Y are linked together form a nitrogen-containing heterocyclic C₄-C₇ ring.

2. The aqueous semiconductor cleaning solution of claim 1, wherein the pH of the solution is between about 2 and about 6.

3. The aqueous semiconductor cleaning solution of claim 1, wherein the at least one alkaline component comprises a hydroxlyamine derivative present in an amount from about 0.3% to about 1% by weight.

4. The aqueous semiconductor cleaning solution of claim 1, wherein the at least one alkaline component comprises hydroxylamine or N,N-diethylhydroxylamine.

5. The aqueous semiconductor cleaning solution of claim 1, wherein the at least one alkaline component comprises a quaternary ammonium compound present in an amount from about 0.5% to about 3% by weight.

6. The aqueous semiconductor cleaning solution of claim 1, wherein the at least one alkaline component comprises choline hydroxide.

7. The aqueous semiconductor cleaning solution of claim 1, which comprises one or more other acid compounds selected from the group consisting of hydrochloric acid, nitric acid, periodic acid, pyrophosphoric acid, fluorosilicic acid, sulfuric acid, methanesulfonic acid, oxalic acid, lactic acid, citric acid, xylenesulfonic acid, toluenesulfonic acid, formic acid, tartaric acid, propionic acid, benzoic acid, ascorbic acid, gluconic acid, malic acid, malonic acid, succinic acid, gallic acid, butyric acid, trifluoracetic acid, and mixtures thereof.

8. The aqueous semiconductor cleaning solution of claim 7, wherein the one or more other acid compounds is glycolic acid, methanesulfonic acid, pyrophosphoric acid, oxalic acid, lactic acid, or citric acid.

9. The aqueous semiconductor cleaning solution of claim 1, wherein the one or more other acids are present in an amount from about 0.2% to about 5% by weight.

10. The aqueous semiconductor cleaning solution of claim 1, wherein the one or (more fluorine-containing compounds are present in an amount from about 0.01% to about 0.1% by weight.

11. The aqueous semiconductor cleaning solution of claim 1, wherein the one or more fluorine-containing compounds comprise ammonium bifluoride and/or ammonium fluoride.

12. The aqueous semiconductor cleaning solution of claim 1, further comprising an organic solvent in an amount from about 5% to about 15% by weight.

13. The aqueous semiconductor cleaning solution of claim 1, wherein the organic solvent comprises an organic acid ester.

14. The aqueous semiconductor cleaning solution of claim 1, further comprising a surfactant.

15. The aqueous semiconductor cleaning solution of claim 1, further comprising one or more alkanolamines selected from the group consisting of monoethanolamine, 2-(2-hydroxylethylamino)ethanol, 2-(2-aminoethoxy)ethanol, N,N,N-tris(2-hydroxyethyl)-ammonia, isopropanolamine, 3-amino-1-propanol, 2-amino-l-propanol, 2-(N-methylamino)ethanol, 2-(2-aminoethylamino)ethanol, and mixtures thereof.

16. The aqueous semiconductor cleaning solution of claim 1, wherein the one or more alkanolamines is present in an amount from about 0.5% to about 5% by weight.

17. The aqueous semiconductor cleaning solution of claim 1, wherein the solution is substantially free from other acid compounds.

18. The aqueous semiconductor cleaning solution of claim 1, wherein the solution is substantially free from fluoride-containing compounds.

19. The aqueous semiconductor cleaning solution of claim 1, wherein the solution is substantially free from alkanolamines.

20. The aqueous semiconductor cleaning solution of claim 1, wherein the solution contains substantially no additional components.

21. The aqueous semiconductor cleaning solution of claim 1, wherein the solution is substantially free from hydroxylamine derivatives.

22. The aqueous semiconductor cleaning solution of claim 1, wherein the solution is substantially free from organic solvents.

23. The aqueous semiconductor cleaning solution of claim 1, wherein the concentration of water is at least about 85% by weight.

24. A dilute aqueous cleaner and residue remover comprising:

water, optionally in a mixture with one or more polar organic solvents, wherein the water is present at least about 75% by weight;

phosphoric acid or salt thereof, present in an amount from about 0.1% to about 6% by weight of 85% phosphoric acid;

optionally, a quaternary ammonium compound, present in the solution in an amount from about 0.2% to about 5% by weight;

optionally, a hydroxylamine derivative, present in the solution in an amount from about 0. 1% to about 5 % by weight not including the counterion of the hydroxylamine derivative salt, if present;

optionally, an alkanolamine, present in the solution in an amount from about 0.2% to about 5% by weight;

optionally, a fluoride-containing compound, present in the solution in an amount from about 0.001% to about 0.5 % by weight;

optionally, an other acid compound, present in the solution in an amount from about 0.05% to about 6% by weight;

optionally, a chelating agent, present in the solution in an amount from about 0. 1% to about 8% by weight;

optionally, a surfactant, present in the solution in an amount from about 0.01% to about 3% by weight.

25. A dilute aqueous cleaner and residue remover consisting essentially of:

about 1.5% to about 2.5% by weight of phosphoric acid;

about 0.5% to about 1% by weight of a hydroxylamine derivative, preferably hydroxylamine; and

about 0.005% to about 0.04% by weight of a fluoride-containing compound, preferably ammonium bifluoride.

26. A dilute aqueous cleaner and residue remover consisting essentially of:

about 1.5% to about 2.5% by weight of phosphoric acid;

about 0.5% to about 1% by weight of a hydroxylamine derivative;

about 0.005% to about 0.04% by weight of a fluoride-containing compound; and

about 0.05% to about 0.2% by weight of a surfactant.

27. A dilute aqueous cleaner and residue remover consisting essentially of:

about 1.5% to about 2.5% by weight of phosphoric acid;

about 0.5% to about 1% by weight of a hydroxylamine derivative, preferably hydroxylamine; and

about 0.005% to about 0.1% by weight of a fluoride-containing compound, preferably ammonium fluoride.

28. A dilute aqueous cleaner and residue remover consisting essentially of:

about 1.5% to about 2.5% by weight of phosphoric acid;

about 0.5% to about 1% by weight of a hydroxylamine derivative;

about 0.005% to about 0.1 % by weight of a fluoride-containing compound; and

about 5% to about 15% by weight of a polar organic solvent.

29. A dilute aqueous cleaner and residue remover consisting essentially of:

about 1.5% to about 2.5% by weight of phosphoric acid; and

about 0.5% to about 1.5% by weight of a quaternary ammonium salt.

30. A dilute aqueous cleaner and residue remover consisting essentially of:

about 1.5% to about 4% by weight of 85% phosphoric acid;

about 0.3% to about 4% by weight of oxalic acid dihydrate;

about 0.3% to about 4% by weight of a monofunctional organic acid;

about 90% to about 99% by weight of water; and

optionally between about 0.1% and about 1% of a chelator, wherein the formulation contains substantially no organic solvents and SARA 3 hazardous compounds.

31. A dilute aqueous cleaner and residue remover consisting essentially of:

optionally about 0.5% to about 6% by weight of 85% phosphoric acid;

about 2% to about 12% by weight of oxalic acid dihydrate;

optionally about 0.2% to about 15% by weight of a monofunctional organic acid;

optionally between about 0.05% and 1.5% by weight of ammonium hydroxide, an alkyl ammonium hydroxide substituted with 2 or 3 alkyl moieties independently selected from methyl and ethyl moieties, or a mixture thereof;

optionally between about 0.1% and about 1% of a chelator; and

water wherein the formulation contains substantially no organic solvents and SARA 3 hazardous compounds.