Cleaning solutions and etchants and methods for using same

• US 7,192,910 B2
• Filed: 10/27/2004
• Issued: 03/20/2007
• Est. Priority Date: 10/28/2003
• Status: Expired due to Fees

• Current Assignee: Sachem, Inc.
• Original Assignee: Sachem, Inc.
• Inventors: Collins, Sian, Wojtczak, William A., Dewulf, Dean
• Primary Examiner(s): WEBB, GREGORY E
• Application Number:
  US10/974,569
• Publication Number:
  US 20050143270A1
• Time in Patent Office: 874 Days
• Field of Search: None
• US Class Current: 510/175
• CPC Class Codes: C11D 2111/22 Electronic devices, e.g. PCBs or semiconductors
• CPC Class Codes: C11D 7/3218 Alkanolamines or alkanolimines
• CPC Class Codes: C11D 7/3227 Ethers thereof
• CPC Class Codes: C11D 7/34 containing sulfur
• CPC Class Codes: C11D 7/36 containing phosphorus
• CPC Class Codes: C11D 7/5004 Organic solvents
• CPC Class Codes: H01L 21/02063 the processing being the formation of vias or contact holes
• CPC Class Codes: H01L 21/02071 the processing being a delineation, e.g. RIE, of conductive layers
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/76814 post-treatment or after-treatment, e.g. cleaning or removal of oxides on underlying conductors

Abstract

Composition for cleaning or etching a semiconductor substrate and method for using the same. The composition may include a fluorine-containing compound as an active agent such as a quaternary ammonium fluoride, a quaternary phosphonium fluoride, sulfonium fluoride, more generally an -onium fluoride or “multi” quaternary -onium fluoride that includes two or more quaternary- onium groups linked together by one or more carbon-containing groups. The composition may further include a pH adjusting acid such as a mineral acid, carboxylic acid, dicarboxylic acid, sulfonic acid, or combination thereof to give a pH of about 2 to 9. The composition can be anhydrous and may further include an organic solvent such as an alcohol, amide, ether, or combination thereof. The composition are useful for obtaining improved etch rate, etch selectivity, etch uniformity and cleaning criteria on a variety of substrates.

Claims

1. A composition useful for cleaning or etching a substrate, comprising:

tetrabutyl phosphonium fluoride;

an acid;

an organic solvent or water or a mixture thereof in an amount from 0 to about 99.8% of the composition by weight; and

a pH of between about 2 and about 9.

2. The composition of claim 1, wherein the salt makes up between about 1% and about 10% by weight of the composition.

3. The composition of claim 1, wherein the organic solvent is an alcohol.

4. The composition of claim 1, wherein the organic solvent is a glyme.

5. The composition of claim 1, wherein the water makes up less than about 5% of the composition by weight.

6. The composition of claim 1, wherein the pH is between about 2 and about 4.

7. The composition of claim 1, further comprising a second salt comprising one or more of a quaternary ammonium salt, a sulfonium salt, and a phosphonium salt.

8. The composition of claim 1, wherein the composition has a free metal ion content of less than about 10 PPB.

9. The composition of claim 1, wherein the composition is capable of etching a DARO layer at a rate greater than it etches a doped oxide layer.

10. The composition of claim 1, wherein the composition is capable of etching an undoped oxide layer at a rate greater than it etches a doped oxide layer.

11. The composition of claim 1, wherein the composition is capable of non-selectively etching a doped oxide layer and an undoped oxide layer.

12. The composition of claim 1, wherein the solvent is a glyme, the water is present in an amount less than about 3%, and the pH is between about 2.5 and about 4.

13. The composition of claim 1, wherein the composition further comprises tetrabutyl phosphonium benzoate.

14. A composition for cleaning or etching a semiconductor substrate, comprising:

a salt containing fluoride and a quaternary ammonium cation comprising at least one alkoxy group or two or more quaternary ammonium groups linked together by one or more carbon-containing groups;

an acid;

a solvent comprising water in an amount from 0 to about 99.8% of the weight of the formulation or an organic solvent in an amount from 0 to 99.8% of the weight of the formulation or a mixture thereof; and

a pH of between about 2 and about 9.

25. A method of cleaning and/or etching and/or patterning a semiconductor substrate, comprising contacting the semiconductor substrate with the composition of claim 14.

15. A composition for cleaning or etching a substrate, obtained by combining ingredients comprising:

a salt containing fluoride and a phosphonium cation;

an acid;

an organic solvent, wherein the organic solvent is one or more selected from the group consisting of tetrahydrofurfuryl alcohol, benzyl alcohol, hexanol, 2-(2-methoxyethoxy)-ethanol, dimethylacetamide, bis-(2-methoxyethyl) ether, diethyleneglycol mono butyl ether, glymes, dipropyleneglycol mono methyl ether, 2-butoxyethanol, 1-cyclohexyl-2-pyrrolidinone, 1-hydroxyethyl-2-pyrrolidinone; and

water as the primary solvent;

wherein the composition has a pH of between about 2 and about 9.

27. A method of cleaning and/or etching and/or patterning a semiconductor substrate, comprising contacting the semiconductor substrate with the composition of claim 15.

28. The composition of claim 15 wherein the acid is present in an amount from about 0.1% to about 5% by weight of the composition.

29. The composition of claim 15 wherein the salt is present in an amount from about 0.1% to about 20% by weight of the composition.

30. The composition of claim 15 wherein the acid is a mineral acid or a sulfonic acid.

16. A composition for cleaning or etching a substrate, obtained by combining ingredients comprising:

a salt containing fluoride and a quaternary ammonium cation comprising at least one alkoxy group or a cation comprising two or more quaternary ammonium groups linked together by one or more carbon-containing groups;

an acid;

an organic solvent; and

water in an amount less than about 5% of the composition by weight;

wherein the composition has a pH of between about 2 and about 9.

26. A method of cleaning and/or etching and/or patterning a semiconductor substrate, comprising contacting the semiconductor substrate with the composition of claim 16.

17. A method for cleaning and/or etching and/or patterning a semiconductor substrate, comprising:

contacting the semiconductor substrate with a composition comprising;

tetrabutyl phosphonium fluoride;

an acid;

an organic solvent or water or a mixture thereof in an amount from 0 to about 99.8% of the composition by weight; and

a pH of between about 2 and about 9.

18. The method of claim 17, wherein the substrate comprises an antireflective coating, amorphous carbon and BPSG, wherein the process further comprises etching a portion of the antireflective coating, and wherein the composition etches the antireflective coating at a rate greater than that at which it removes the amorphous carbon or the BPSG.

20. The method of claim 17, wherein the process further comprises:

(a) etching a dielectric to expose a contact material on the substrate, thereby forming a residue; and

(b) contacting the contact material with a cleaning formulation to remove the residue, wherein the contact material comprises one or more of a metal, doped silicon, polysilicon, and silicide.

22. The method of claim 17, wherein the process comprises:

(a) etching a metal to form an interconnect metal line, thereby forming a residue;

(b) contacting the metal with the composition to remove the residue.

19. A method of cleaning and/or etching and/or patterning a semiconductor substrate, comprising:

contacting the semiconductor substrate with a composition obtained by combining ingredients comprising;

tetrabutyl phosphonium fluoride;

an acid;

an organic solvent or water or a mixture thereof in an amount from 0 to about 99.8% of the composition by weight; and

a pH of between about2 and about9.

21. The method of claim 19, wherein the process further comprises:

(a) etching a dielectric to expose a contact material on the substrate, thereby forming a residue; and

(b) contacting the contact material with a cleaning formulation to remove the residue, wherein the contact material is comprises one or more of a metal, doped silicon, polysilicon, and silicide.

23. The method of claim 19, wherein the process comprises:

(a) etching a metal to form an interconnect metal line, thereby forming a residue; and

(b) contacting the metal with the composition to remove the residue.

24. The method of claim 19, wherein the substrate comprises an antireflective coating, amorphous carbon and BPSG, wherein the process further comprises etching a portion of the antireflective coating, and wherein the composition etches the antireflective coating at a rate greater than that at which it removes the amorphous carbon or the BPSG.