Co/Cu selective wet etchant

Patent metadata

Field	Value
Publication number	US-12110436-B2
Application number	US-202017756223-A
Country	US
Kind code	B2
Filing date	Sep 30, 2020
Priority date	Dec 20, 2019
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

Abstract

The disclosed and claimed subject matter relates to wet etchants exhibiting high copper and cobalt etching rates where the etching rate ratio between the two metals can be varied. The wet etchants have a composition comprising a formulation consisting of: at least one alkanolamine having at least two carbon atoms, at least one amino substituent and at least one hydroxyl substituent with the amino and hydroxyl substituents attached to two different carbon atoms; at least one pH adjuster for adjusting the pH of the formulation to between approximately 9 and approximately 12; at least one chelating agent; and water.

First claim

What is claimed is:

1. A formulation consisting of:
(i) at least one alkanolamine having at least two carbon atoms, at least one amino substituent and at least one hydroxyl substituent with the amino and hydroxyl substituents attached to two different carbon atoms;
(ii) at least one pH adjuster comprising an inorganic acid or an organic acid selected from the group consisting of citric acid, sulfuric acid, phosphoric acid, oxalic acid, malonic acid, lactic acid, adipic acid, acetic acid, trifluoroacetic acid, methanesulfonic acid, toluenesulfonic acid and a halogen acids of the formula H—X wherein X═F, Cl, Br, or I;
(iii) at least one chelating agent;
(iv) water;
(v) optionally at least one water miscible solvent; and
(vi) optionally at least one organic wettability adjusting material,
wherein the formulation has a pH between approximately 9 and approximately 12.

2. The formulation of claim 1 , wherein the (v) at least one water miscible solvent is present.

3. The formulation of claim 2 , wherein the at least one water miscible solvent comprises one or more of ethylene glycol, propylene glycol (PG), 1,4-butanediol, tripropylene glycol methyl ether, propylene glycol propyl ether, diethylene gycol n-butyl ether (BDG), dipropylene glycol methyl ether (DPM), hexyloxypropylamine, poly(oxyethylene)diamine, dimethyl sulfoxide (DMSO), tetrahydrofuran, tetrahydrofurfuryl alcohol, glycerol, alcohols, sulfolane, sulfoxides, and mixtures thereof.

4. The formulation of claim 2 , wherein the at least one water miscible solvent comprises from about 10 wt. % to about 20 wt. % of propylene glycol.

5. The formulation of claim 1 , wherein the (v) at least one water miscible solvent is present and the (vi) at least one wettability adjusting material is present.

6. The formulation of claim 1 , wherein the at least one alkanolamine comprises a compound of formula (I):

wherein each of R 1 and R 2 is independently selected from H, an unsubstituted C 1 -C 6 alkyl, a substituted C 1 -C 6 alkyl, a branched C 3 -C 6 alkyl and a C 1 -C 6 alkylamino.

7. The formulation of claim 1 , wherein the at least one alkanolamine comprises

8. The formulation of claim 1 , wherein the at least one alkanolamine comprises

9. The formulation of claim 1 , wherein the at least one alkanolamine comprises

10. The formulation of claim 1 , wherein the at least one alkanolamine comprises

11. The formulation of claim 1 , wherein the at least one pH adjuster comprises hydrofluoric acid.

12. The formulation of claim 1 , wherein the at least one pH adjuster comprises methanesulfonic acid.

13. The formulation of claim 1 , wherein the at least one chelating agent is one or more of ethylenediaminetetraacetic acid (EDTA), butylenediaminetetraacetic acid, (1,2-cyclohexylenediamine)tetraacetic acid (CyDTA), diethylenetriaminepentaacetic acid (DETPA), ethylenediaminetetrapropionic acid, (hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), N, N, N′, N′-ethylenediaminetetra(methylenephosphonic) acid (EDTMP), triethylenetetraminehexaacetic acid (TTHA), 1,3-diamino-2-hydroxypropane-N,N,N′,N′-tetraacetic acid (DHPTA), iminodiacetic acid, methyliminodiacetic acid, propylenediaminetetraacetic acid, nitrotriacetic acid (NTA), citric acid, tartaric acid, gluconic acid, saccharic acid, glyceric acid, oxalic acid, phthalic acid, maleic acid, mandelic acid, malonic acid, lactic acid, salicylic acid, propyl gallate, pyrogallol, 8-hydroxyquinoline, and cysteine.

14. The formulation of claim 1 , wherein the at least one chelating agent comprises EDTA.

15. The formulation of claim 1 , wherein the at least one chelating agent comprises CyDTA.

16. The formulation of claim 1 , wherein the at least one chelating agent comprises iminodiacetic acid.

17. The formulation of claim 1 , wherein the at least one water miscible solvent comprises from about 10 wt. % to about 20 wt. % of diethylene glycol butyl ether.

18. The formulation of claim 1 , wherein the formulation has a copper etching rate of greater than approximately 50 Å/minute and a cobalt etching rate of greater than approximately 50 Å/minute when copper and cobalt are coupled.

19. The formulation of claim 1 , wherein the formulation has a copper to cobalt etching rate ratio of approximately 0.9 to approximately 2.25 when copper and cobalt are coupled.

20. The formulation of claim 1 , wherein the formulation has a copper to cobalt etching rate ratio of approximately 1.0 when copper and cobalt are coupled.

21. A method of etching a substrate comprising copper and cobalt, the method comprising:
(i) applying a composition comprising the formulation of claim 1 onto the substrate.

Assignees

• Versum Mat Us Llc

Inventors

• Chang Chung-Yi
• Liu Wen Dar
• Lee Yi-Chia

Classifications

• H10P50/667 Primary

  by liquid etching only · CPC title

• C09K13/06

  with organic material · CPC title

• C23F1/40

  for etching other metallic material · CPC title

• C23F1/34

  for etching copper or alloys thereof · CPC title

• C23F1/44 Primary

  Compositions for etching metallic material from a metallic material substrate of different composition · CPC title