Aqueous cleaning composition containing copper-specific corrosion inhibitor for cleaning inorganic residues on semiconductor substrates
View Patent ↗A semiconductor wafer cleaning formulation, including 1-21% wt. fluoride source, 20-55% wt. organic amine(s), 0.5-40% wt. nitrogenous component, e.g., a nitrogen-containing carboxylic acid or an imine, 23-50% wt. water, and 0-21% wt. metal chelating agent(s). The formulations are useful to remove residue from wafers following a resist plasma ashing step, such as inorganic residue from semiconductor wafers containing delicate copper interconnecting structures.
1. A method for fabricating a semiconductor wafer including the steps comprising: cleaning the wafer by contacting same with a cleaning formulation, wherein said cleaning formulation comprises at least one fluoride source, water and a nitrogen-containing carboxylic acid or imine selected from the group consisting of: iminodiacetic acid (IDA), glycine, 1,1,3,3-tetramethylguanidine (TMG), CH 3 C(═NCH 2 CH 2 OH)CH 2 C(O)N(CH 3 ) 2 , CH 3 C(═NCH 2 CH 2 OCH 2 CH 2 OH)CH 2 C(O)N(CH 3 ) 2 , CH 3 C(═NH)CH 2 C(O)CH 3 , (CH 3 CH 2 ) 2 NC(═NH)N(CH 3 CH 2 ) 2 , HOOCCH 2 N(CH 3 ) 2 , HOOCCH 2 N(CH 3 )CH 2 COOH, and COOH—CH 2 —NRR′, wherein each of R and R′ is independently selected from the group consisting of hydrogen, alkyl, aryl, and carboxylic acid, and wherein at least one fluoride source is selected from the group consisting of: triethanolammonium fluoride (TEAF), diglycolammonium fluoride (DGAF), and triethylamine tris (hydrogen fluoride) (TREAT-HF).
2. The method of claim 1 , wherein the cleaning composition further comprises at least one organic amine.
3. The method of claim 1 , wherein the cleaning composition further comprises at least one metal chelating agent.
4. The method of claim 3 , wherein said metal chelating agent is selected from the group consisting of:
acetoacetamide,
ammonium carbamate,
ammonium pyrrolidinedithiocarbamate (APDC),
dimethyl malonate,
methyl acetoacetate,
N-methyl acetoacetamide,
2,4-pentanedione,
tetramethylammonium thiobenzoate,
tetramethylammonium trifluoroacetate, and
tetramethylthiuram disulfide (TMTDS).
5. The method of claim 2 , wherein said organic amine is selected from the group consisting of:
diglycolamine (DGA),
methyldiethanolamine (MDEA),
pentamethyldiethylenetriamine (PMDETA),
triethanolamine (TEA),
triethylenediamine (TEDA),
hexamethylenetetramine,
3, 3-iminobis (N,N-dimethylpropylamine), and
monoethanolamine.
6. The method of claim 1 , wherein the cleaning composition has pH greater than 7.
7. The method of claim 1 , wherein the cleaning composition further comprises at least one chelating agent, wherein said metal chelating agent has the formula:
X—CHR—Y, in which
R is either hydrogen, a C 1 -C 8 alkyl, an aryl or an alkenyl, and
X and Y are functional groups containing multiply-bonded moieties having electron-withdrawing properties.
8. The method of claim 1 , wherein the cleaning composition further comprises at least one chelating agent, wherein said metal chelating agent has the formula, R 1 R 2 R 3 R 4 N +− O 2 CCF 3 in which each of the R groups is hydrogen, C 1 -C 8 alkyl, aryl or alkenyl.
9. The method of claim 7 , wherein X and Y may be the same as or different from one another and are selected from the group consisting of CONH 2 , CONHR′, CN, NO 2 , SOR′, and SO 2 Z, where R′ is a C 1 -C 8 alkyl group and Z is a hydrogen, halo or C 1 -C 8 alkyl group.
10. The method of claim 1 , further comprising:
plasma etching a metalized layer from a surface of the wafer; and
plasma ashing a resist from the surface of the wafer, prior to cleaning the wafer.
11. The method of claim 1 , wherein the nitrogen-containing carboxylic acid or imine is iminodiacetic acid.
12. The method of claim 1 , wherein the fluoride ion source is triethanolammonium fluoride (TEAF).
13. The method of claim 2 , wherein the at least one organic amine is pentamethyldiethylenetriamine.
14. The method of claim 2 , wherein the at least one organic amine is triethanolamine.
15. The method of claim 1 , wherein the nitrogen-containing carboxylic acid or imine is HOOCCH 2 N(CH 3 )CH 2 COOH.
16. The method of claim 3 , wherein said metal chelating agent is 2,4-pentanedione.
17. The method of claim 1 , wherein the fluoride ion source is triethylamine tris (hydrogen fluoride).
18. The method of claim 2 , wherein the at least one organic amine is monoethanolamine.
19. The method of claim 2 , wherein the at least one organic amine is methyldiethanolamine.
20. The method of claim 1 , wherein the amount of water is in a range from 23-50 wt %, based on the total weight of the composition.