Aqueous cleaning composition containing copper-specific corrosion inhibitor for cleaning inorganic residues on semiconductor substrate
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, comprising:
plasma etching a metalized layer from a surface of the wafer;
plasma ashing a resist from the surface of the wafer;
cleaning the wafer by contacting same with a cleaning formulation, comprising, by weight between about 1% and about 21% fluoride source, between about 20% and about 55% organic amino, between about 23% and about 50% water, a metal chelating agent and between about 0.5% and about 40% of a nitronenous component including a compound of the formula COOH-CH 2 -NRR′, wherein each of R and R′ is independently selected from the group consisting of hydrogen, alkyl, aryl and carboxylic acids.
2. The method of claim 1 , wherein said fluoride source comprises a fluoride species selected from the group consisting of:
animonium fluoride; and
triethanolammnonium fluoride (TEAF).
3. The method of claim 1 , wherein said organic amine(s) comprise an amine selected from the group consisting of:
diglycolamine (DGA),
methyldiethanolamine (MDEA),
pentamethyldiethylenetriamine (PMDETA),
triethanolamine (TEA), and
triethylenediamine (TEDA).
4. The method of claim 1 wherein said nitrogenous component comprises a species selected from the group consisting of:
iminodiacetic acid (IDA);
glycine;
nitrilotriacetic acid (NTA); and
1,3,3-tetramethylguanidine (TMG).
5. The method of claim 1 , including at least one metal chelating agent selected from the group consisting of:
acetoacetamide,
ammonium carbamate,
ammonium pyrrolidinedithiocarbamate (APDC),
dimethyl malonate,
methyl acetoacetate,
N-methyl acetoacetamide,
2,4-pentanedione,
tetramethylammoniuim thiobenzoate,
tetramethylammonium trifluoroacetate, and
tetramethylthiuram disulfide (TMTDS).
6. The method of claim 1 wherein said fluoride source comprises a species selected from the group consisting of:
ammonium fluoride,
triethanolammonium fluoride (TEAF),
diglycolammonium fluoride (DGAF),
tetramethylamnmonium fluoride (TMAF), and
triethylamine tris (hydrogen fluoride) (TREAT-HF).
7. The method of claim 1 wherein said organic amine(s) comprises an amine 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.
8. The method of claim 1 wherein said nitrogenous component comprises a species from the group consisting of:
iminodiacetic acid (IDA);
glycine;
nitrilotriacetic acid (NTA);
1,1,3,-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 ;
HOOCH 2 N(CH 3 ) 2 ; and
HOOCCH 2 N(CH 3 )CH 2 COOH.
9. The method of claim 1 wherein said fluoride source comprises a species selected from the group consisting of:
ammonium fluoride,
triethanolammonium fluoride (TEAF),
diglycolammonium fluoride (DGAF),
tetramethylammonium fluoride (TMAF), and
triethylamine tris (hydrogen fluoride) (TREAT-HF);
said organic amine(s) comprise a species 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;
said nitrogenous component comprises a species selected from the group consisting of:
iminodiacetic acid (IDA),
glycine,
nitrilotriacetic acid (NTA),
1,1,3,3-tetramethylguanidine (TMG);
and said formulation includes a metal chelating agent comprising a species 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).
10. The method of claim 1 wherein said fluoride source comprises a compound having the general formula R 1 R 2 R 3 R 4 NF in which each of the R groups is independently selected from hydrogen atoms and aliphatic groups, and wherein said formulation includes a metal chelating agent of the formula:
X-CHR-Y, in which
R is either hydrogen or an aliphatic group and
X and Y are functional groups containing multiply bonded moieties having electron-withdrawing properties.
11. The method of claim 10 wherein each of X and Y is independently selected from CONH 2 , CONHR′, CN, NO 2 , SOR′, and SO 2 Z in which R′ is alkyl and Z is hydrogen, halo, or alkyl.
12. The method of claim 1 wherein said fluoride source comprises a compound having the formula R 1 R 2 R 3 R 4 NF in which each of the R groups is hydrogen or aliphatic, and wherein said formulation includes a metal chelating agent of the formula, R 1 R 2 R 3 R 4 N +− O 2 CCF 3 in which each of the R groups is independently hydrogen or aliphatic.
13. The method of claim 1 , wherein the cleaning formulation comprises by weight between about 1% and about 21 % metal chelating agent.