# Patent

## Title
Composition and method for cleaning semiconductor substrates comprising an alkyl diphosphonic acid

## Abstract

The compositions and methods for the removal of residues and contaminants from metal or dielectric surfaces comprises at least one alkyl diphosphonic acid, at least one second acidic substance at a mole ratio of about 1:1 to about 10:1 in water, and pH is adjusted to from about 6 to about 10 with a basic compound, and optionally a surfactant. Particularly, a composition and method of cleaning residues after chemical mechanical polishing of a copper or aluminum surface of the semiconductor substrates. One of the embodiment is the method of using the compositions in dilution, wherein the solution may be diluted with DI water at dilution ratios, for example, of up to 1:10, up to 1:50, up to 1:100, up to 1:150, up to 1:250, and up to about 1:500 or any ratios therein.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is continuation-in-part of application Ser. No. 12/888,569 filed Sep. 23, 2010, which claims priority from U.S. Provisional Appl. No. 61/254,669, filed Oct. 24, 2009, and are incorporated herein by reference in its entirety.


FIELD OF THE INVENTION
The present invention relates to compositions and methods for removal of chemical residues from metal or dielectric surfaces or for chemical mechanical polishing of a copper or aluminum surface including an aqueous solution comprising an alkyl disphosphonic acid compound applied for a time sufficient to remove the chemical residues.
BACKGROUND OF THE INVENTION
U.S. Pat. Nos. 6,143,705, 6,310,019, 6,440,856, 6,514,352, 6,514,921, 6,534,458, 6,541,434, 6,716,803, 7,250,391, 7,265,005, 7,312,186, and 7,541,322 discuss various compositions and methods of cleaning semiconductor substrates containing phosphonic acids.
U.S. Pat. Nos. 6,395,693 and 6,541,434 describe a method and composition for cleaning contaminants from the surface of a semiconductor wafer after the semiconductor wafer has been chemically-mechanically polished, the method comprising contacting the surface of the semiconductor wafer having abrasive particle and metal ion contaminants with a composition comprising carboxylic acid is present in an amount of about 2 wt. % or less, said amine-containing compound is present in an amount of about 0.1 wt. % or less, and said phosphonic acid is present in an amount of about 2 wt. % or less. The cleaning composition desirably has a pH of about 4-6. Preferably, the cleaning composition has a pH of about 4.5-5.5. The weight ratio of phosphonic acid to carboxylic acid is 1:1.
U.S Patent Application No. 20010051597 discusses an aqueous solution of a citric acid concentration of more than 1 vol %, and the chelating agent is added into the aqueous solution containing the citric acid by 10 ppm or more. The weight ratio of phosphonic acid to carboxylic acid, such is 1:1000 (i.e 10 ppm of phosphonic acid to 1% citric acid)
U.S Patent Application No. 20070090094 discloses a method of chemically mechanically polishing a substrates and a polishing system comprising hydrogen peroxide, an organic acid, at least one heterocyclic compound comprising at least one nitrogen atom and water.
Phosphonic acid, in particular 1-hydroxyethane 1,1-diphosphonic acid (commonly termed HEDPA) has been in commercial use for many years as a corrosion inhibitor and as a complex agent. It is well understood when HEDPA is used in quantities less than 30 parts to million parts water, it acts as corrosion inhibitor. Above 150 parts to million parts water, it acts as a chelating agent. In the range 30-150 parts HEDPA to one million parts water there is a dead zone; the HEDPA does not perform.
It is known that HEDPA combined with a surfactant produces a synergistic result. The surfactant not only functions as a dispersant but also improves the residue dissolving performance of the HEDPA when the HEDPA is used in strength above 150 parts to million parts water.
SUMMARY OF THE INVENTION
The present invention relates to composition and method for cleaning semiconductor substrates. The invention has particular application as a residues and particles remover in semiconductor manufacturing processes and the like.
One embodiment encompassed is a cleaning solution that contains an alkyl diphosphonic acid (component a) of the basic structure:




wherein R1 and R2 are either the same or different and select from the group consisting of hydrogen (H), hydroxide (OH), chloride (Cl), alkyl or aryl having between 1 to about 8 carbon atoms and alkyl or aryl amine. Some compositions contain a second acidic compound (component b), a buffering amount of one or more basic compounds (component c) to adjust pH from about 6 to about 10, optionally from 0% by weight and up to 5% by weight of a surfactant (component d), and a balance of water (component e).

The compositions encompassed may have a mole ratio of alkyl diphosphonic acid to a second acidic compound, or compounds, of about 1:1 to about 10:1.
The cleaning solution comprises from about 1% to about 50% by weight of the alkyl disphosphonic acid.
One of the embodiment, at least one or more alkyl diphosphonic acid may be present in solution.
One of the embodiment, at least one or more second acidic compound may be present in solution.
Preferred alkyl disphosphonic acids are 1 hydroxyethane 1,1 diphosphonic acid, methylene disphosphonic acid, hydroxymethylene diphosphonic acid, dichloromethylene disphosphonic acid, hydroxycyclohexylmethylene disphosphonic acid, 1-hydroxy-3-aminopropane 1,1 diphosphonic acid, 1-hydroxy-4-aminobutane 1,1 diphosphonic acid, and the like.
The second acidic compound may, for example, be phosphonic acid, sulfonic acid, methanesulfonic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid, xylenesulfonic acid, toluenesulfonic acid, phosphono formic acid, sulfamic acid, 2-amino ethane sulfonic acid, fluoro boric acid, aminotris(methylenephosphonic acid), N carboxymethylaminomethanephosphonic acid, carboxylic acid or mixtures thereof.
The composition may also contain an organic carboxylic acid. Where the composition contains an organic carboxylic acid, that acid may be aspartic acid, adipic acid, oxalic acid, lactic acid, citric 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, hydroxy acetic acid, iminodiacetic acid and the like.
It is also contemplated that the compositions may include a buffering basic compound, such as potassium hydroxide, sodium hydroxide and metal ion free base or mixture of compounds.
The metal ion free basic compound or mixture may be at least one basic compounds consisting of hydroxylamine freebase or a hydroxylamine derivative, tetraalkylammonium hydroxide, TMAH pentahydrate, BTMAH (benzyltetramethylammonium hydroxide), TBAH, choline, or THEMAH (Tris(2-hydroxyethyl)methylammonium hydroxide)), monoethanolamine, 2-(2-hydroxylethylamino)ethanol, 2-(2-aminoethoxy)ethanol, N,N,N-tris(2-hydroxyethyl)-ammonia, isopropanolamine, 3-amino-1-propanol, 2-amino-1-propanol, 2-(N-methylamino)ethanol, 2-(2-aminoethylamino)ethanol, tris(hydroxymethyl)aminoethane, and the like.
A preferred pH range is from about 6 to about 10.
Surfactants may also be used in the compositions encompassed herein. Preferred surfactants include nonionic, anionic, cationic, and/or amphoteric, polyacrylic acid or its water-soluble salts, or hydrolyzed poly-maleic anhydride or its water soluble salts and the like
One of the embodiment is method of using the compositions described herein involves providing a substrate having a surface comprising copper-containing conductor and a low-k dielectric material and one or more of etching residue, planarization residue, and copper oxide disposed on the surface, which generated from a damascene or dual damascene manufacturing processes or thereof; contacting the surface of the substrate with an effective amount of solution comprising alkyl diphosphonic acid of the basic structure:




wherein R1 and R 2 are either the same or different and select from the group consisting of hydrogen (H), hydroxide (OH), chloride (Cl), alkyl or aryl having between 1 to about 8 carbon atoms and alkyl or aryl amine, adding a second acidic compound and a buffering amount of basic compounds to adjust pH from about 6 to about 10, optionally including from 0% by weight and up to 5% by weight of a surfactant, with a balance of water. This composition is contacted with a substrate for a time and at a temperature sufficient to remove the resist, residues, and/or copper oxide. The preferred temperature for the method is from about ambient to about 70° C., more preferably about 50° C., and the preferred contact time is between about 10 seconds and about 10 minutes. The compositions described herein may be used in a cleaning process following a chemical mechanical planarization step during the semiconductor fabrication process, as well as other appropriate cleaning processes known to one of skill in the art.

One of the embodiment is the method of using the compositions in dilution, wherein the solution may be diluted with DI water at dilution ratios, for example, of up to 1:10, up to 1:50, up to 1:100, up to 1:150, up to 1:250, and up to about 1:500 or any ratios therein.


DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to the provision of an improved cleaning solution which is a blend of alkyl diphosphonic acid and a second acidic substance at a mole ratio of about 1:1 to about 10:1 in water.
The alkyl diphosphonic acid of the basic structure:




wherein R1 and R2 are either the same or different and select from the group consisting of hydrogen (H), hydroxide (OH), chloride (Cl), alkyl or aryl having between 1 to about 8 carbon atoms and alkyl or aryl amine.

Non limiting examples of the alkyl diphosphonic acids are as follow:













Name
R1
R2
Structure







-hydroxyethane 1,1-diphosphonic acid
OH
CH3






 


methylene diphosphonic acid (MDP)
H
H






 


Hydroxymethylene diphosphonic acid (HMDP)
OH
H






 


Dichloromethylene diphosphonic acid (Cl2MDP)
Cl
Cl






 


Hydroxycyclohexylmethylene diphosphonic acid (HCMDP)
OH










 


1-hydroxy-3 aminopropane 1,1-diphosphonic acid  (APD)
OH
—CH2CH2NH2






 


1-hydroxy-4-aminobutane 1,1 diphosphonic acid
OH
—CH2CH2CH2NH2













In accordance with the invention, from 1 mole to 10 moles of one or more alkyl diphosphonic acid are mixed with one mole of one or more a second acidic compounds.
The mixture or blend is adjusted to a pH of about 6 to about 10 with a buffering amount of basic compounds.
D. I water is added to the mixture or blend to balance the total weight to 100%.
Suitable alkyl diphosphonic acids include, but not limited to, 1 hydroxyethane 1,1 diphosphonic acid, methylene disphosphonic acid, hydroxymethylene diphosphonic acid, dichloromethylene disphosphonic acid, hydroxycyclohexylmethylene disphosphonic acid, 1-hydroxy-3-aminopropane 1,1 diphosphonic acid, 1-hydroxy-4-aminobutane 1,1 diphosphonic acid, and the like.
Suitable second acidic substances include phosphonic acid, sulfonic acid, methanesulfonic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid, xylenesulfonic acid, toluenesulfonic acid, phosphono formic acid, sulfamic acid, 2-amino ethane sulfonic acid, fluoro boric acid, aminotris(methylenephosphonic acid), N carboxymethylaminomethanephosphonic acid, carboxylic acid or mixtures thereof.
Non limiting examples of suitable carboxylic acid include aspartic acid, adipic acid, oxalic acid, lactic acid, citric 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, hydroxy acetic acid, iminodiacetic acid and the like.
Suitable basic compounds include potassium hydroxide, sodium hydroxide and metal ion free basic compounds consisting of an ammonium compound, such as e.g. ammonium hydroxide, tetraalkylammonium hydroxide, TMAH pentahydrate, BTMAH (benzyltetramethylammonium hydroxide), TBAH, choline, or THEMAH (Tris(2-hydroxyethyl)methylammonium hydroxide)), hydroxylamine freebase, a hydroxylamine derivative, such as e.g N,N diethylhydroxylamine, an alkanolamine component including but not limited to hydrazine, ethylenediamine, monoethanolamine, N,N diethylamino ethanol, 2-(2-hydroxylethylamino)ethanol, 2-(2-aminoethoxy)ethanol, N,N,N-tris(2-hydroxyethyl)-ammonia, isopropanolamine, 3-amino-1-propanol, 2-amino-1-propanol, 2-(N-methylamino)ethanol, 2-(2-aminoethylamino)ethanol, tris(hydroxymethyl)aminoethane, or mixtures thereof.
The cleaning solution can comprise from about 1% to about 50% by weight of at least one alkyl disphosphonic acid.
Preferably, alkyl diphosphonic acid may be present in solution in the amount from about 25% to about 50% by weight.
The basic buffering agent may be present in an amount up to about 25% by weight.
Preferably the pH of the cleaning solution is from about 6 to about 10.
EXAMPLES
Example 1
The following is a list of blends prepared for the purpose of conducting tests:



















Mol

Solute
Solute

Wt


Composition
1000 Gram quantities
Wt
Mole
Mole
Gram
Wt %
ratio






















1
1-hydroxy ethanediphosphonic acid
206
6
0.69
142.1
14.21%
3.79



Dodecylbenzene sulfonic acid
326.5
1
0.115
37.55
3.75%



25% TMAH adjust to pH 6



—



water



Bal



Total



1000


2
1-hydroxy ethanediphosphonic acid
206
6
0.69
142.1
14.21%
9.66



phosphono formic acid
128
1
0.115
14.72
1.47%



25% TMAH adjust to pH 7



—



water



Bal



Total



1000


3
1-hydroxy ethanediphosphonic acid
206
6
0.69
142.1
14.21%
13.73



Oxalic Acid
90
1
0.115
10.35
1.04%



65% (Tris(2-hydroxyethyl)methylammonium



—



hydroxide)) adjust to pH 9



water



Bal



Total



1000


4
1-hydroxy ethanediphosphonic acid
206
6
0.69
142.1
14.21%
12.74



Sulfamic acid
97
1
0.115
11.16
1.12%



45% Choline Hydroxide adjust to pH 9



—



water



Bal



Total



1000


5
1-hydroxy ethanediphosphonic acid
206
6
0.69
142.1
14.21%
16.26



Hydroxy acetic acid
76
1
0.115
8.74
0.87%



N,N diethylhydroxylamine/monoethanol amine



—



(1:1 wt ratio) adjust pH to 7



water



Bal



Total



1000


6
1-hydroxy ethanediphosphonic acid
206
6
0.69
142.1
14.21%
14.08



Fluoro boric acid
87.8
1
0.115
10.1
1.01%



Ethylenene diamine adjust pH to 10



—



water



Bal



Total



1000


7
1-hydroxy ethanediphosphonic acid
206
6
0.69
142.1
14.21%
85.24



2-amino ethane sulfonic acid
14.5
1
0.115
1.668
0.17%



25% TMAH adjust to 7



—



water



Bal



Total



1000


8
1-hydroxy ethanediphosphonic acid
206

0.3
61.8
6.18%
2.92



hydroxy methylenephosphonic acid
112
6
0.3
33.6
3.36%



Dodecylbenzene sulfonic acid
326.5
1
0.1
32.65
3.27%



N,N diethylamino ethanol adjust pH to 7



—



water



Bal



Total



1000


9
1-hydroxy-3 aminopropane 1,1-diphosphonic acid
235
6
1.2
282
28.20%
18.55



Hydroxyacetic acid
76
1
0.2
15.2
1.52%



tris(hydroxymethyl)aminoethane adjust pH to 9



—



Water



Bal



Total



1000


10
methylene disphosphonic acid
176
6
0.69
121.4
12.10%
8.64



2-amino ethane sulfonic acid
125
1
0.115
14.4
1.40%



28% ammonium hydroxide adjust pH to 7



—



Water



Bal



Total



1000


11
1-hydroxy ethanediphosphonic acid
206
6
0.69
142.1
14.21%
6.44



Citric acid
192
1
0.115
22.08
2.21%



65% (Tris(2-hydroxyethyl)methylammonium



—



hydroxide)) adjust to pH 9



water



Bal



Total



1000


12
hydroxy methylenephosphonic acid
112
6
0.6
67.2
6.72%
2.06



Dodecylbenzene sulfonic acid
326.5
1
0.1
32.65
3.27%



25% TMAH adjust pH to 10



—



water



Bal



Total



1000


13
1-hydroxy ethanediphosphonic acid
206
6
0.69
142.1
14.21%
16.26



Hydroxy acetic acid
76
1
0.115
8.74
0.87%



Potassium hydroxide adjust pH to 7



—



water



Bal



Total



1000


14
1-hydroxy ethanediphosphonic acid
206
10
1.15
236.9
23.69%
21.24



Sulfamic acid
97
1
0.115
11.16
1.12%



Potassium Hydroxide adjust to pH 7



—



water



Bal



Total



1000


15
1-hydroxy ethanediphosphonic acid
206
3
0.345
71.07
7.11%
8.13



Hydroxy acetic acid
76
1
0.115
8.74
0.87%



Potassium Hydroxide adjust pH to 7



—



water



Bal



Total



1000


16
1-hydroxy ethanediphosphonic acid
206
3
0.345
71.07
7.11%
7.04



Fluoro boric acid
87.8
1
0.115
10.1
1.01%



Potassium hydroxide adjust pH to 10



—



water



Bal



Total



1000


17
1-hydroxy ethanediphosphonic acid
206
1
0.115
23.69
2.37%
14.21



2-amino ethane sulfonic acid
14.5
1
0.115
1.668
0.17%



25% TMAH adjust to 7



—



water



Bal



Total



1000


18
1-hydroxy ethanediphosphonic acid
206
4
0.4
82.4
8.24%
3.90



hydroxy methylenephosphonic acid
112
4
0.4
44.8
4.48%



Dodecylbenzene sulfonic acid
326.5
1
0.1
32.65
3.27%



65% (Tris(2-hydroxyethyl)methylammonium



—



hydroxide)) adjust to pH 9



water



Bal



Total



1000


19
1-hydroxy ethanediphosphonic acid
206
8
0.92
189.5
18.95%
12.88



phosphono formic acid
128
1
0.115
14.72
1.47%



25% TMAH adjust to pH 7



—



water



Bal



Total



1000


20
1-hydroxy ethanediphosphonic acid
206
8
0.92
189.5
18.95%
18.31



Oxalic Acid
90
1
0.115
10.35
1.04%



65% (Tris(2-hydroxyethyl)methylammonium



—



hydroxide)) adjust to pH 9



water



Bal



Total



1000


21
hydroxy methylenediphosphonic acid
192
1
0.1
19.2
1.92%
0.58



Dodecylbenzene sulfonic acid
326.5
1
0.1
32.65
3.27%



25% TMAH adjust pH to 10



—



water



Bal



Total



1000









This example illustrates the significance of the mole ratio of alkyl phosphonic acid to second acidic component in the cleaning composition of the present invention in reducing slurry particle remnants and metal ion remnants on the surface of a substrate.
In some applications the compositions may be diluted with DI water at dilution ratios, for example, of up to 1:10, up to 1:50, up to 1:100, up to 1:150, up to 1:250, and up to about 1:500 or any ratios therein.
Silicon oxide wafers were immersed for 30 seconds with copper-contaminated slurry. The oxide wafers were then washed with each of the above listed compositions and followed by rinsing in DI water. There was a complete and relatively fast dissolution of the remnants. Each of the blends removed the slurry particle remnants and metal ion from the surface of the substrates without attacking the exposed metal surfaces.
Example 2
The procedure was repeated with 5 parts of Composition 9 in 100 parts of D.I water (1:20 water dilution). Effectively, this solution contains 1.343% of 1-hydroxy-3 aminopropane 1,1-diphosphonic acid and 0.122% of hydroxyacetic acid. It still maintains a 6:1 mole ratio of alky diphosphonic to second acidic compound. The same results were obtained by the use of this mixture.
Example 3
The procedure was repeated with 1 parts of Composition 5 in 100 parts of D.I water (1:100 water dilutions). Effectively, this solution contains 0.141% of 1-hydroxy ethanediphosphonic acid and 0.009% of hydroxyacetic acid. It still maintains 6:1 mole ratio of alky diphosphonic to second acidic compound. The same results were obtained by the use of this mixture.
Example 4
The procedure was repeated with 1 parts of Composition 15 in 100 parts of D.I water (1:100 water dilutions). Effectively, this solution contains 0.0711% of 1-hydroxy ethanediphosphonic acid and 0.009% of hydroxyacetic acid. It still maintains 3:1 mole ratio of alky diphosphonic to second acidic compound. The same results were obtained by the use of this mixture.
Example 5
The procedure was repeated with 5 parts of Composition 14 in 100 parts of D.I water (1:20 water dilution). Effectively, this solution contains 1.185% of 1-hydroxy ethanediphosphonic acid and 0.056% of sulfamic acid. It still maintains a 10:1 mole ratio of alky diphosphonic to second acidic compound. The same results were obtained by the use of this mixture.
Example 6















Trade name/

Wt



Ingredients
product name
Supplier
(Grams)
%



















1-hydroxy ethane-
DEQUEST
Thermphos
580
13.0%


diphosphonic acid
2010





CAS#2809-21-4






Hydroxy acetic acid
Glycolic Acid
Du Pont
60
1.3%


Hydroxylamine

San Fu
600
13.4%


Freebase (50%)






Triethanolamine (85%)
TEA85
Dow
470
10.5%


water


2760
61.7%


Total


4470
100.0%









The pH of the above solution is 7.24-7.26. The solution can be used as is or further diluted with water if necessary.

Example 7















Trade name/

Wt



Ingredients
product name
Supplier
(Grams)
%



















1-hydroxy ethane-
DEQUEST
Thermphos
530
11.2%


diphosphonic acid
2010





CAS#2809-21-4






Amino tris (methylene
DEQUEST
Thermphos
90
1.9%


phosphonic acid) in
2000





water CAS#6419-19-8






N,N Diethylhydroxyl-

Arkema
310
6.6%


amine 85%






CAS#3710-84-7






Monoethanolamine
MEA
Dow
310
6.6%


water


3480
73.7%


Total


4420
100.0%









The solution is 7.7. The solution can be used as is or further diluted with water if desired.

Example 8


















Mol

Solute
Solute



Composition
1000 Gram quantities
Wt
Mol
Mole
Gram
wt %





















1
1-hydroxy ethanediphosphonic acid
206
6
1.26
259.6
25.96%



Oxalic Acid
90
1
0.21
18.9
1.89%



65% (Tris(2-hydroxyethyl)methylammonium



—



hydroxide)) adjust to pH 9



water



Bal



Total



1000


2
1-hydroxy ethanediphosphonic acid
206
6
1.5
309
30.90%



Hydroxy acetic acid
76
1
0.25
19
1.90%



N,N diethylhydroxylamine/monoethanol amine



—



(1:1 wt ratio) adjust pH to 7



water



Bal



Total



1000


3
1-hydroxy-3 aminopropane 1,1-diphosphonic
235
6
1.2
282
28.20%



acid



Hydroxyacetic acid
76
1
0.2
15.2
1.52%



tris(hydroxymethyl)aminoethane adjust pH to 9



—



Water



Bal



Total



1000


4
1-hydroxy ethanediphosphonic acid
206
6
1.32
271.9
27.19%



Citric acid
192
1
0.22
42.24
4.22%



65% (Tris(2-hydroxyethyl)methylammonium



—



hydroxide)) adjust to pH 9



water



Bal



Total



1000


5
1-hydroxy ethanediphosphonic acid
206
6
1.8
370.8
37.08%



Hydroxy acetic acid
76
1
0.3
22.8
2.28%



Potassium hydroxide adjust pH to 7



—



water



Bal



Total



1000


6
1-hydroxy ethanediphosphonic acid
206
3
1.5
309
30.90%



Hydroxy acetic acid
76
1
0.5
38
3.80%



Potassium Hydroxide adjust pH to 6



—



water



Bal



Total



1000


7
1-hydroxy ethanediphosphonic acid
206
8
1.6
329.6
32.96%



Oxalic Acid
90
1
0.2
18
1.80%



65% (Tris(2-hydroxyethyl)methylammonium



—



hydroxide)) adjust to pH 9



water



Bal



Total



1000


8
1-hydroxy ethanediphosphonic acid
206
1
1.26
259.6
25.96%



Oxalic Acid
90
1
1.26
113.4
11.34%



65%(Tris(2-hydroxyethyl)methylammonium



—



hydroxide)) adjust to pH 9



water



Bal



Total



1000


9
hydroxy methylene diphosphonic acid
192
1
1.5
288
28.8



Dodecylbenzene sulfonic acid
326.5
1
1.5
489.75
49



25% TMAH adjust pH to 6



—



water



Bal



Total



1000









It will be obvious to any skill in the art that the effectiveness of removing particle and metal ion contaminant will depend on the seriousness of the problem. A higher concentration of the blended composition will produce faster results.
The composition of the invention does not sequest and there is no dead or non-performance zone of cleaning.
The alky diphosphonic acid acts as a chelating agent throughout a large concentration range, starting with a few parts to million parts water.
In another embodiment, the composition contains a surfactant which enhance the cleaning performance of the composition over the composition with alkyl diphosphonic acid alone.
Preferably a surfactant is admixed with the blend to both keep it from re-precipitating and to enhance the cleaning ability of the composition. There are several types of surfactants available. Readily available and relatively inexpensive surfactants include anionic, cationic, non-ionic, amphoteric, or polyacrylic acid, water-soluble salts of polyacrylic acid, hydrolyzed poly-maleic anhydride, or water-soluble salts of polyacrylic acid.
While the invention has been described and illustrated herein by reference to various specific materials, procedures and examples, it is understood that the invention is not restricted to the particular combinations of materials and procedures selected for that purpose. Numerous variations of such details can be implied as will be appreciated by those skilled in the art. It is intended that the specification and examples considered as exemplary, only, with the true scope and spirit of the invention being indicated by the following claims. All references, patents, patent applications referred to in this application are herein being incorporated by reference in their entirety.

## Claims

1. A cleaning solution comprises
a. from greater than 25% to about 50% by weight of an alkyl diphosphonic acid of the basic structure:




 wherein R1 and R2 are either the same or different and select from the group consisting of hydrogen (H), hydroxide (OH), chloride (Cl), alkyl or aryl having between 1 to about 8 carbon atoms and alkyl or aryl amine;
b. at least one or more second, acidic compound or mixtures thereof;
c. a buffering amount of one or more basic compounds to adjust pH from about 6 to about 10;
d. from 0% by weight and up to 5% by weight of a surfactant; and
e. water;
wherein the mole ratio of alkyl diphosphonic acid to second acidic compound is from about 1:1 to about 10:1.

2. The composition according to claim 1 in which the alkyl disphosphonic acid is selected from the group consisting of 1 hydroxyethane 1,1 diphosphonic acid, methylene disphosphonic acid, hydroxymethylene diphosphonic acid, dichloromethylene disphosphonic acid, hydroxycyclohexylmethylene disphosphonic acid, 1-hydroxy-3-aminopropane 1,1 diphosphonic acid, 1-hydroxy-4-aminobutane 1,1 diphosphonic acid or mixtures thereof.

3. The composition of claim 1 wherein the second acidic compound is selected from the group consisting of phosphonic acid, sulfonic acid, methanesulforiic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid, xylenesulfonic acid, toluenesulfonic acid, phosphono formic acid, sulfamic acid, 2-amino ethane sulfonic acid, fluoro boric acid, aminotris(methylenephosphonic acid), N carboxymethylaminomethanephosphonic acid, aspartic acid, adipic acid, oxalic acid, lactic acid, citric 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, hydroxy acetic acid, iminodiacetic acid or mixtures thereof.

4. The composition according to claim 1 in which the buffering base is selected from the group consisting of potassium hydroxide, sodium hydroxide, metal ion free base and mixtures thereof.

5. The composition according to claim 4 in which the buffering metal ion free base is at least one basic compounds selected from the group consisting of hydroxylamine freebase, a hydroxylamine derivative, tetraalkylammonium hydroxide, TMAH pentahydrate, BTMAH (benzyltetramethylammonium hydroxide), TBAH, choline, or THEMAH (Tris(2-hydroxyethyl)methylammonium hydroxide)), monoethanolamine, 2-(2-hydroxylethylamino)ethanol, 2-(2-aminoethoxy)ethanol, N,N,N-tris(2-hydroxyethyl)-ammonia, isopropanolamine, 3-amino-1-propanol, 2-amino-1propanol, 2-(N-methylamino)ethanol, 2-(2-aminoethylainino)ethanol, tris(hydroxymethyl)aminoethane, and mixtures thereof.

6. The composition according to claim 1, wherein the composition has a pH of from about 7 to about 8.

7. The composition of claim 1 wherein the surfactants are selected from the group consisting of anionic, cationic, non-ionic, amphoteric or polyacrylic acid, water-soluble salts of polyacrylic acid, hydrolyzed poly-maleic anhydride, or water-soluble salts of polyacrylic acid.

8. A method of cleaning semiconductor substrates comprising the steps of:
i. providing a substrate having a surface comprising copper-containing conductor and a low-k dielectric material and one or more of etching residue, planarization residue, and copper oxide disposed on the surface, which generated from a damascene or dual damascene manufacturing processes or thereof;
ii. contacting the surface of the substrate with an effective amount of solution comprising:
a. from greater than 25% to about 50% by weight of an;alkyl diphosphonic acid of the basic structure:






 wherein :R1 and R2 are either the same or different and select from the group consisting of hydrogen (H), hydroxide (OH), chloride (Cl), alkyl or aryl having between 1 to about 8 carbon atoms and alkyl or aryl amine;
b. at least one or more of a second acidic compound;
c. a buffering amount of one or more basic compounds to adjust pH from about 6 to about 10;
d. from 0% by weight and up to 5% by weight of a surfactant; and
e. water
wherein the mole ratio of alkyl diphosphonic acid to second acidic compound is from about 1:1 to about 10:1


for a time and at a temperature sufficient to remove the resist, residues, and/or copper oxide.

9. The method according to claim 8 in which the alkyl disphosphonic is selected from the group consisting of 1 hydroxyethane 1,1 diphosphonic acid, methylene disphosphonic acid, hydroxymethylene diphosphonic acid, dichloromethylene disphosphonic acid, hydroxycyclohexylmethylene disphosphonic acid, 1-hydroxy-3-aminopropane 1,1 diphosphonic acid, 1-hydroxy-4-aminobutane 1,1 diphosphonic acid and mixtures thereof.

10. The method of claim 8, wherein the second acidic compound is selected from the group consisting of phosphonic acid, sulfonic acid, methanesulfonic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid,xylenesulfonic acid, toluenesulfonic acid, phosphono formic acid, sulfamic acid, 2-amino ethane sulfonic acid, fluoro boric acid, aminotris(methylenephosphonic acid), N carboxymethylaminomethanephosphonic acid, aspartic acid, adipic acid, oxalic acid, lactic acid, citric 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, hydroxy acetic acid, iminodiacetic acid or mixtures thereof.

11. The method according to claim 8 in which the buffering base is selected from the group consisting of potassium hydroxide, sodium hydroxide and metal ion free base and mixture thereof.

12. The method according to claim 11 in which the buffering metal ion free base is at least one basic compounds selected from the group consisting of hydroxylamine freebase or a hydroxylamine derivative, tetraalkylammonium hydroxide, TMAH pentahydrate, BTMAH (benzyltetramethylammonium hydroxide), TBAH, choline, or THEMAH (Tris(2-hydroxyethyl)methylammonium hydroxide)), monoethanolamine, 2-(2-hydroxylethylamino)ethanol, 2-(2-aminoethoxy)ethanol, N,N,N-tris(2-hydroxyethyl)-ammonia, isopropanolamine, 3-amino-1-propanol, 2-amino-1-propanol, 2-(N-methylamino)ethanol, 2-(2-aminoethylamino)ethanol, tris(hydroxymethyl)aminoethane, or mixtures thereof.

13. The method of claim 8, wherein the pH range is about 7 to about 8.

14. The method of claim 8 wherein the surfactants are selected from the group consisting of anionic, cationic, non-ionic, amphoteric or polyacrylic acid, water-soluble salts of polyacrylic acid, hydrolyzed poly-maleic anhydride, or water-soluble salts of polyacrylic acid.

15. The method of claim 8 wherein the cleaning process is following chemical mechanical planarization step during the semiconductor fabrication processes.

16. The method of claim 8, wherein said composition is diluted with DI water at dilution ratio from at least 1:1 to about 1:500.