U.S. patent application number 10/577129 was filed with the patent office on 2007-10-11 for cleaning agent for substrate and cleaning method.
This patent application is currently assigned to WAKO PURE CHEMICAL INDUSTRIES, LTD.. Invention is credited to Ichiro Hayashida, Masahiko Kakizawa, Hironori Mizuta.
Application Number | 20070235061 10/577129 |
Document ID | / |
Family ID | 34510177 |
Filed Date | 2007-10-11 |
United States Patent
Application |
20070235061 |
Kind Code |
A1 |
Mizuta; Hironori ; et
al. |
October 11, 2007 |
Cleaning Agent for Substrate and Cleaning Method
Abstract
The present invention provides a cleaning agent for a substrate
and a cleaning method thereof, which can effectively remove fine
particles (particles) present on a surface of substrate or
impurities derived from various kinds of metals (metallic
impurities), without causing roughness surface of a substrate, in
particular, a semiconductor substrate, and without causing
corrosion or oxidation of metal wirings, in particular, copper
wirings, provided on a surface of substrate, and can further remove
at the same time a carbon defect present on a surface of substrate,
without removing a metal corrosion inhibitor--Cu film, in
particular, a Cu-BTA film. The present invention provides a
cleaning agent for a substrate comprising [I] an organic acid
having at least one carboxyl group and/or [II] a complexing agent,
and [III] an organic solvent selected from the group consisting of
(1) monohydric alcohols, (2) alkoxyalcohols, (3) glycols, (4)
glycol ethers, (5) ketones and (6) nitriles, and a cleaning method
for a surface of substrate, which comprises the surface of
substrate is treated with said cleaning agent.
Inventors: |
Mizuta; Hironori; (Saitama,
JP) ; Kakizawa; Masahiko; (Saitama, JP) ;
Hayashida; Ichiro; (Saitama, JP) |
Correspondence
Address: |
WESTERMAN, HATTORI, DANIELS & ADRIAN, LLP
1250 CONNECTICUT AVENUE, NW
SUITE 700
WASHINGTON
DC
20036
US
|
Assignee: |
WAKO PURE CHEMICAL INDUSTRIES,
LTD.
1-2, Doshimachi 3-chome, Chuo-ku
Osaka
JP
541-0045
|
Family ID: |
34510177 |
Appl. No.: |
10/577129 |
Filed: |
October 13, 2004 |
PCT Filed: |
October 13, 2004 |
PCT NO: |
PCT/JP04/15040 |
371 Date: |
January 5, 2007 |
Current U.S.
Class: |
134/2 ;
257/E21.228; 510/175; 510/254; 510/405; 510/407; 510/434 |
Current CPC
Class: |
C11D 7/262 20130101;
H01L 21/02052 20130101; C23G 5/032 20130101; C11D 7/261 20130101;
C11D 7/263 20130101; C11D 11/0047 20130101; C11D 7/264 20130101;
C11D 7/3245 20130101; C11D 7/36 20130101; C23G 5/02 20130101 |
Class at
Publication: |
134/002 ;
510/175; 510/254; 510/405; 510/407; 510/434 |
International
Class: |
C11D 1/68 20060101
C11D001/68 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 27, 2003 |
JP |
2003-365588 |
Claims
1. A cleaning agent for a substrate comprising [I] an organic acid
having at least one carboxyl group and/or [II] a complexing agent,
and [III] an organic solvent selected from the group consisting of
(1) monohydric alcohols, (2) alkoxyalcohols, (3) glycols, (4)
glycol ethers, (5) ketones and (6) nitrites.
2. The cleaning agent according to claim 1, wherein the learning
agent contains [I] the organic acid having at least one carboxyl
group and [II] the complexing agent.
3. The cleaning agent according to claim 1, wherein the cleaning
agent is an aqueous solution.
4. The cleaning agent according to claim 1, wherein the organic
solvent is one selected from the group consisting of methanol,
ethanol, isopropyl alcohol, 2-methoxyethanol,
2-(2-butoxyethoxy)ethanol, ethylene glycol, diethylene glycol
monomethyl ether, acetone and acetonitrile.
5. The cleaning agent according to claim 1, wherein the complexing
agent is one selected from the group consisting of a compound
having at least one phosphonic acid group in a molecule, and an
ammonium salt or an alkali metal salt thereof.
6. The cleaning agent according to claim 5, wherein the compound
having at least one phosphonic acid group in a molecule is one
selected from the group consisting of nitrogen-containing
polyphosphonic acids having 1 to 6 nitrogen atoms and 1 to 8
phosphonic acid groups in a molecule, an aryl polyphosphonic acid,
an alkylene polyphosphonic acid, alkane polyphosphonic acids which
may have a hydroxyl group, and an ammonium salt or an alkali metal
salt thereof.
7. The cleaning agent according to claim 5, wherein the compound
having at least one phosphonic acid group in a molecule is one
selected from the group consisting of nitrogen-containing
polyphosphonic acids having 1 to 6 nitrogen atoms and 1 to 8
phosphonic acid groups in a molecule, alkane polyphosphonic acids
which may have a hydroxyl group, and an ammonium salt or an alkali
metal salt thereof.
8. The cleaning agent according to claim 6, wherein the
nitrogen-containing polyphosphonic acids having 1 to 6 nitrogen
atoms and 1 to 8 phosphonic acid groups in a molecule is one
selected from the group consisting of an alkylamino
poly(alkylphosphonic acid), a mono- or polyalkylenepolyamine
poly(alkylphosphonic acid), a nitrilo-poly(alkylphosphonic acid),
and an ammonium salt or an alkali metal salt thereof.
9. The cleaning agent according to claim 1, wherein the complexing
agent is one selected from the group consisting of:
ethylenediaminebis(methylenephosphonic acid) [EDDPO];
ethylenediaminetetrakis(ethylenephosphonic acid);
ethylenediaminetetrakis(methylenephosphonic acid) [EDTPO];
hexamethylenediaminetetrakis(methylenephosphonic acid);
isopropylenediaminebis(methylenephosphonic acid);
isopropylenediamintetra(methylenephosphonic acid);
propanediaminetetra(ethylenephosphonic acid)[PDTMP];
diaminopropanetetra(methylenephosphonic acid)[PDTPO];
diethylenetriaminepenta(ethylenephosphonic acid) [DEPPO];
diethylenetriaminepenta(methylenephosphonic acid) [DETPPO];
triethylenetetraminehexa(ethylenephosphonic acid) [TETHP];
triethylenetetraminehexa(methylenephosphonic acid) [TTHPO];
nitrilotris(methylenephosphonic acid)[NTPO]; ethylidenediphosphonic
acid; 1-hydroxyethylidene-1,1'-diphosphonic acid [HEDPO];
1-hydroxypropylidene-1,1'-diphosphonic acid; and
1-hydroxybutylidene-1,1'-diphosphonic acid.
10. The cleaning agent according to claim 1, wherein the organic
acid is an organic acid having 2 or 3 carboxyl groups.
11. The cleaning agent according to claim 1, wherein the organic
acid is a dicarboxylic acid or an oxycarboxylic acid.
12. The cleaning agent according to claim 11, wherein the
oxycarboxylic acid is an oxydicarboxylic acid or an
oxytricarboxylic acid.
13. The cleaning agent according to claim 11, wherein the
dicarboxylic acid is one selected from the group consisting of an
oxalic acid, a malonic acid, a succinic acid, a glutaric acid, an
adipic acid, a pimelic acid, a maleic acid, a fumaric acid and a
phthalic acid.
14. The cleaning agent according to claim 11, wherein the
oxycarboxylic acid is a malic acid, a tartaric acid, or a citric
acid.
15. The cleaning agent according to claim 1, wherein the organic
acid is a dicarboxylic acid or an oxycarboxylic acid; the
complexing agent is one selected from the group consisting of
nitrogen-containing polyphosphonic acid having 1 to 6 nitrogen
atoms and 1 to 8 phosphonic acid groups in a molecule, alkane
polyphosphonic acids which may have a hydroxyl group, and an
ammonium salt or an alkali metal salt thereof; and the organic
solvent is one selected from the group consisting of monohydric
alcohols, alkoxyalcohols, glycols, glycol ethers, ketones and
nitrites.
16. The cleaning agent according to claim 1, wherein pH of the
cleaning agent is 0.5 to 6.5.
17. The cleaning agent according to claim 1, wherein the substrate
is a semiconductor.
18. The cleaning agent according to claim 1, wherein the substrate
is one with metallic wiring provided thereon.
19. The cleaning agent according to claim 18, wherein the metallic
wiring is a copper wiring.
20. The cleaning agent according to claim 1, wherein the substrate
is one treated with a slurry containing benzotriazole or a
derivative thereof.
21. A cleaning method for a surface of substrate, which comprises
treating the surface of substrate with the cleaning agent according
to claim 1.
22. The cleaning method according to claim 21, wherein the
treatment with the cleaning agent is dipping the surface of
substrate in the cleaning agent according to claim 1 or spraying
said cleaning agent on the surface of substrate.
23. The cleaning method according to claim 21, wherein physical
cleaning is further used in combination.
24. The cleaning method according to claim 21, wherein the
substrate is one after subjecting to a chemical mechanical
polishing process.
25. The cleaning method according to claim 21, wherein the
substrate is a semiconductor.
26. The cleaning method according to claim 21, wherein the
substrate is one with metallic wiring provided thereon.
27. The cleaning method according to claim 26, wherein the metallic
wiring is a copper wiring.
28. The cleaning method according to claim 21, wherein the
substrate is one after subjecting to the treatment process with a
slurry containing benzotriazole or a derivative thereof.
Description
TECHNICAL FIELD
[0001] The present invention relates to a cleaning agent for a
surface of substrate, in particular, for a surface of semiconductor
substrate provided with copper wiring thereon, and to a cleaning
method thereof.
BACKGROUND ART
[0002] Recently, with the spread of multilayer wirings on a surface
of semiconductor substrate, a so-called chemical mechanical
polishing (CMP) technique, by which a semiconductor substrate is
mechanically polished and planarized, has been used in producing
devices.
[0003] In particular, accompanied to the tendency to a highly
integrated LSI in recent years, a wiring used has been changed from
conventional aluminum to copper (Cu) which has a lower electric
resistance, and thus the CMP technique (Cu-CMP) has become
essential, when semiconductors having a multilayer structure, in
which copper wirings are provided in many layers on the surface
thereof, are produced.
[0004] The CMP is a method for planarizing a surface of
semiconductor substrate using a slurry containing abrasive grains
such as silica, aluminum and ceria, and an object to be polished is
silicon oxide films, wirings, plugs, or the like.
[0005] And the semiconductor surface after the CMP process is
contaminated with a large amount of abrasive grain itself used,
metals contained in the slurry, or metallic impurities derived from
metallic wirings or metallic plug polished, and further various
kinds of particles.
[0006] Contamination of the surface of semiconductor substrate with
the metallic impurities or the particles affects electric
characteristics of the semiconductor, and causes to lose
reliability of devices. Further, since device is destructed when
metallic contamination is significant, it is necessary to introduce
a post-CMP cleaning process to remove metallic impurities or
particles from the surface of semiconductor substrate.
[0007] Heretofore, various kinds of cleaning agents have been
developed for use in various types of cleaning processes such as a
cleaning process following the CMP process, and provided for
use.
[0008] On the other hand, since metallic copper on a surface of
semiconductor is highly active, and easily corroded by a slight
oxidizing power, it tends to cause an increase of wiring resistance
or wire breaking. Therefore, it is known that corrosion of metallic
copper on a surface of semiconductor can be prevented by adding
various kinds of metal corrosion inhibitors [for example, an
aromatic type compound represented by benzotriazole(BTA)s and
imidazoles, a cyclic compound such as mercaptoimidazole and
mercaptothiazole, an aliphatic alcohol type compound which has a
mercapto group in a molecule and a carbon to which said mercapto
group is bonded and a carbon to which a hydroxyl group is bonded
links adjacently such as mercaptoethanol and mercaptoglycerol]. In
particular, in a slurry used in the above-described Cu-CMP process,
an inhibitor for metal corrosion as described above is added to
prevent the polished metal surface from corrosion.
[0009] The metal corrosion inhibitor is supposed to be adsorbed on
a surface of metal (for example, Cu) of semiconductor surface and
form a metal corrosion inhibiting film (for example, a metal
corrosion inhibitor--Cu film such as a Cu-BTA film), and thus to
prevent corrosion of the metal (for example, Cu).
[0010] However, these metal corrosion inhibitors may remain on a
surface of semiconductor as a so-called carbon defect.
[0011] There has been a problem that when a semiconductor having a
carbon defect remaining on a surface thereof is subjected to heat
treatment in the subsequent process, during working of a device or
the like, the carbon defect is burnt to oxidize a wiring material
resulting in deterioration of the device performance, or an
apprehension that multilayer wiring executed without removing the
carbon defect tends to put the flatness of upper layer part into
disorder, and make a correct lamination difficult to cause a
serious defect in working of the device.
[0012] However, a cleaning agent, which is conventionally used in
various cleaning processes such as a post-CMP cleaning process,
cannot sufficiently remove the carbon defect, or apt to remove a
metal corrosion inhibiting film that is needed to prevent corrosion
of metal surface as described above. Thus, an effective means has
not been found which can remove only the carbon defect while
maintaining the metal corrosion inhibiting effect, without removing
a metal corrosion inhibitor--Cu film, in particular, a Cu-BTA film
as described above.
Patent Reference 1: JP-A-4-130100 (claims 1 to 3)
Patent Reference 2:
JP-A-7-79061 (claim 1)
Patent Reference 3:
JP-A-10-72594
Patent Reference 4: JP-A-10-26832 (claims 1 to 15)
Patent Reference 5: JP-A-11-316464 (claims 1 to 6)
Patent Reference 6: JP-A-2002-20787 (claims 1 to 36)
Patent Reference 7: JP-A-2003-13266 (claims 1 to 42)
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0013] The present invention has been made under such circumstances
as described above, and provides a cleaning agent for a substrate
and a cleaning method thereof, which can effectively remove fine
particles (particles) present on a surface of substrate or
impurities (metallic impurities) derived from various kinds of
metals, without causing roughness surface of a substrate, in
particular, a semiconductor substrate, and without causing
corrosion or oxidation of metal wirings, in particular, copper
wirings, provided on a surface of substrate, and further can remove
at the same time the carbon defect present on a surface of
substrate, without removing a metal corrosion inhibitor--Cu film,
in particular, a Cu-BTA film.
MEANS TO SOLVE THE PROBLEMS
[0014] The present invention consists of the following items:
[0015] (1) a cleaning agent for a substrate comprising [I] an
organic acid having at least one carboxyl group and/or [II] a
complexing agent, and [III] an organic solvent selected from the
group consisting of (1) monohydric alcohols, (2) alkoxyalcohols,
(3) glycols, (4) glycol ethers, (5) ketones and (6) nitriles;
and
[0016] (2) a cleaning method for a substrate surface, which
comprises treating the substrate surface with said cleaning agent
according to the above item (1).
[0017] Namely, the present inventors have, after intensively
studying a way to achieve the above-described object, found that
not only particles and metallic impurities on a surface of
substrate can be removed without causing roughness surface of a
semiconductor substrate or corrosion or oxidation of metal wirings,
in particular, cupper wirings provided on a semiconductor
substrate, but also a carbon defect remaining on a substrate
surface can also be easily removed at the same time without losing
a metal corrosion inhibitor--Cu film, in particular, a Cu-BTA film,
by cleaning the substrate surface using a cleaning agent for
substrate comprising [I] an organic acid having at least one
carboxyl group and/or [II] a complexing agent and [III] a specified
organic solvent, in particular, a cleaning agent for substrate
comprising [I] an organic acid having at least one carboxyl group,
[II] a complexing agent and [III] a specified organic solvent, and
further that specified solvents, among organic solvents, are
superior in exhibiting such an effect, and a combined use of the
specified organic solvents and a compound having at least one
phosphonic acid group in a molecule (a phosphonic acid type
complexing agent) as a complexing agent is particularly preferable,
and accomplished the present invention.
[0018] The reason why the above-described object can be achieved by
the present invention is not sure, but is supposed as follows. For
instance, a carbon defect becomes unstable in the optimum pH range
generated by an organic acid and is hence dissolved in an organic
solvent. On the other hand, a metal corrosion inhibiting film (for
example, a metal corrosion inhibitor--Cu film such as a Cu-BTA
film) is not dissolved in an organic solvent or water in the above
pH range, and thus a dissolution selection ratio of the carbon
defect and the metal corrosion inhibiting film (for example, a
Cu-BTA film) is increased, and only the carbon defect can be
removed without removing the metal corrosion inhibiting film (in
particular, a Cu-BTA film) while the metal corrosion inhibiting
effect is maintained.
[0019] The organic solvent according to the present invention is
water-soluble, but all of water-soluble organic solvents cannot
necessarily be used. Those which can satisfy the object of the
present invention include, for example, monohydric alcohols such as
saturated aliphatic monohydric alcohols having 1 to 10 carbon
atoms, preferably 1 to 8 carbon atoms, and more preferably 1 to 5
carbon atoms, unsaturated aliphatic monohydric alcohols having 2 to
12 carbon atoms, preferably 2 to 10 carbon atoms, and more
preferably 2 to 6 carbon atoms; alkoxyalcohols having 3 to 20
carbon atoms, preferably 3 to 16 carbon atoms, and more preferably
3 to 10 carbon atoms; glycols having 2 to 40 carbon atoms,
preferably 2 to 20 carbon atoms, and more preferably 2 to 16 carbon
atoms; glycol ethers having 3 to 40 carbon atoms, preferably 3 to
30 carbon atoms, and more preferably 3 to 20 carbon atoms; ketones
having 3 to 40 carbon atoms, preferably 3 to 30 carbon atoms, and
more preferably 3 to 10 carbon atoms; nitrites such as simple
nitrites having 2 to 10 carbon atoms, preferably 2 to 8 carbon
atoms, and more preferably 2 to 4 carbon atoms, x-aminonitriles
having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, and
more preferably 4 to 10 carbon atoms, .alpha.-hydroxynitriles
having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, and
more preferably 4 to 10 carbon atoms, .beta.-aminonitriles having 4
to 20 carbon atoms, preferably 4 to 15 carbon atoms, and more
preferably 4 to 10 carbon atoms, dinitriles having 4 to 20 carbon
atoms, preferably 4 to 15 carbon atoms, and more preferably 4 to 10
carbon atoms, .alpha.-unsaturated nitrites having 5 to 30 carbon
atoms, preferably 5 to 20 carbon atoms, and more preferably 5 to 18
carbon atoms, .alpha.-benzene nitrites having 8 to 30 carbon atoms,
preferably 8 to 20 carbon atoms, and more preferably 8 to 15 carbon
atoms, and heterocyclic nitrites having 5 to 30 carbon atoms,
preferably 5 to 20 carbon atoms, and more preferably 5 to 15 carbon
atoms.
[0020] Specific examples are as follows. Monohydric alcohols
include, for example, saturated aliphatic monohydric alcohols such
as methanol, ethanol, n-propylalcohol, isopropylalcohol, 1-butanol,
2-butapanol, isobutylalcohol, tert-butylalcohol, 1-pentanol,
2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentylalcohol,
sec-butylalcohol, tert-pentylalcohol, 3-methyl-2-butanol,
neopentylalcohol, 1-hexanol, 2-methyl-1-pentanol,
4-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol,
3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, 1-nonanol,
3,5,5-trimethyl-1-hexanol, 1-decanol, 1-undecanol, 1-dodecanol,
cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol,
3-methylcyclohexanol, 4-methylcyclohexanol, 2-ethylhexyl alcohol,
capryl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol,
lauryl alcohol, tridecyl alcohol, myristyl alcohol, pentadecyl
alcohol, cetyl alcohol, isocetyl alcohol, hexadecyl alcohol,
heptadecyl alcohol, stearyl alcohol, oleyl alcohol, octyldodecyl
alcohol, nonadecyl alcohol, eicosyl alcohol, ceryl alcohol,
melissyl alcohol, .alpha.-terpineol, abietinol and fusel oil;
unsaturated aliphatic monohydric alcohols such as allyl alcohol,
propargyl alcohol, benzyl alcohol, methallyl alcohol, 2- or
3-butenyl alcohol, 2-pentenyl alcohol, furfuryl alcohol and
tetrahydrofurfuryl alcohol.
[0021] Alkoxyalcohols include, for example, 2-methoxyethanol,
2-ethoxyethanol, 2-(2-methoxy)ethoxyethanol,
2-(2-butoxyethoxy)ethanol, 2-propoxyethanol, 2-butoxyethanol,
3-methoxy-3-methyl-1-butanol, 2-(methoxymethoxy)ethanol,
2-isopropoxyethanol, 2-butoxyethanol and 2-isopentyloxyethanol.
Glycols include, for example, ethylene glycol, propylene glycol,
butylene glycol, hexylene glycol, diethylene glycol, dipropylene
glycol, trimethylene glycol, triethylene glycol, tetraethylene
glycol, polyethylene glycol, polypropylene and tetraethylene
glycol.
[0022] Glycol ethers include, for example, ethylene glycol
monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol
mono n-propyl ether, ethylene glycol mono n-butyl ether, ethylene
glycol dimethyl ether, ethylene glycol diethyl ether, diethylene
glycol monomethyl ether, diethylene glycol monoethyl ether,
diethylene glycol monobutylether, diethylene glycol monohexyl
ether, diethylene glycol dimethyl ether, diethylene glycol diethyl
ether, triethylene glycol monomethyl ether, triethylene glycol
monoethyl ether, 1-methoxy-2-propanol, 1-ethoxy-2-propanol,
propylene glycol monoethyl ether, dipropylene glycol monomethyl
ether, dipropylene glycol monoethyl ether, tripropylene glycol
monomethyl ether, polyethylene glycol monomethyl ether and
3-methoxy-3-methyl-1-butanol.
[0023] Ketones include, for example, acetone, methyl ethyl ketone,
2-pentanone, 3-pentanone, 2-hexanone, cyclohexanone, methyl
isobutyl ketone, 2-heptanone, 4-heptanone, diisobutyl ketone,
acetyl acetone, mesityloxide, phorone, isophorone, cyclohexanone,
methylcyclohexanone, acetophenone, camphor, cyclopentanone and
hexafluoroacetylacetone.
[0024] Nitriles include, for example, simple nitriles such as
acetonitrile, propionitrile, n-butyronitrile and isobutyronitrile;
.alpha.-aminonitriles such as .alpha.-aminopropionitrile,
.alpha.-aminomethylthiobutyronitrile, .alpha.-aminobutyronitrile
and aminoacetonitrile; .alpha.-hydroxylnitriles such as
lactonitrile, hydroxyacetonitrile and
.alpha.-hydroxy-.gamma.-methylthiobutyronitrile;
.beta.-aminonitriles such as amino-3-propionitrile; dinitriles such
as malononitrile, succinonitrile and adiponitrile;
.alpha.-unsaturated nitrites such as acrylonitrile and
methacrylonitrile; .alpha.-benzenenitriles such as
homoveratrinitrile and benzonitrile; heterocyclic nitrites such as
nicotinonitrile and isonicotinonitrile.
[0025] Among these, saturated aliphatic monohydric alcohols,
alkoxyalcohols, glycols, glycol ethers, and simple nitrites are
preferable, and further, methanol, ethanol, isopropyl alcohol,
2-methoxyethanol, 2-(2-butoxyethoxy)ethanol, ethylene glycol,
diethylene glycol monomethyl ether, acetone and acetonitrile are
more preferable, because these compounds have a superior ability
for removing the carbon defect.
[0026] The organic solvent according to the present invention may
be used alone or in combination of two or more kinds.
[0027] The organic solvent according to the present invention is
contained to remove a carbon defect which remains on a surface of
substrate, in particular, a surface of semiconductor substrate with
metal wirings of Cu or the like provided thereon, which has been
treated with a slurry containing a metal corrosion inhibitor in a
CMP treatment or the like.
[0028] The organic solvent according to the present invention can
remove a carbon defect without removing a metal corrosion
inhibiting film (for example, a metal corrosion inhibitor--Cu film
such as a Cu-BTA film) which has been formed on a surface of
semiconductor substrate, and also can remove a carbon defect
without dissolving, corroding, oxidizing or decomposing apparatus
components relating to device production such as semiconductor
materials, wiring materials and plug materials.
[0029] The carbon defect is derived from slurry additives added to
a slurry, for example, aromatic compounds such as a metal corrosion
inhibitor [for example, BTAs and benzimidazoles (JP-A-7-79061 or
the like)], in particular, from BTAs such as BTA or BTA
derivatives. BTA or BTA derivatives include, for example,
benzotriazole, lower alkylbenzotriazoles such as 4- or
5-methylbenzotriazole, 4- or 5-ethylbenzotriazole, 4- or
5-propylbenzotriazole, 4- or 5-isopropylbenzotriazole, 4- or
5-n-butylbenzotriazole, 4- or 5-isobutylbenzotriazole, 4- or
5-pentylbenzotriazole, 4- or 5-hexylbenzotriazole;
5-methoxybenzotriazole, 1-hydroxybenzotriazole,
5-hydroxybenzotriazole, dihydroxypropylbenzotriazole,
carboxybenzotriazole, 2,3-dicarboxypropylbenzotriazole,
1-[N,N-bis(2-ethylhexyl)aminomethyl]benzotriazole, 1-[maleic
acid]benzotriazole, 1-(substitited aminomethyl)-tolyltriazole
(Trade Name: IRGAMET 42, from Ciba-Geigy Aktiengesellshaft),
[1,2,3-benzotriazole-1-methyl], [1,2,4-triazole-1-methyl],
[2-ethylhexyl]amine, bis[(1-benzotriazole)methyl]sulfonic acid,
3-amino-1,2,4-triazole, 4- or 5-chlorobenzotriazole, 4- or
5-nitrobenzotriazole, benzotriazole monoethanolamine salt,
benzotriazole diethylamine salt, benzotriazole cyclohexylamine
salt, benzotriazole morpholine salt, benzotriazole isopropylamine
salt, methylbenzotriazole cyclohexylamine salt, o-tolyltriazole,
m-tolylbenzotriazole and p-tolyltriazole.
[0030] It is supposed that the carbon defect is formed by these
slurry additives (for example, BTAs) which, for example, melt by a
pressure or the like in a CMP process then solidify by cooling on a
metal corrosion inhibiting film (for example, a Cu-BTA film) formed
on a semiconductor substrate with metal wiring such as of Cu and Ag
provided thereon.
[0031] The complexing agent according to the present invention is
not particularly limited so long as it forms a complex with
metallic impurities, and includes, for example, a compound having
at least one carboxyl group in a molecule, a compound having at
least one phosphonic acid group in a molecule, N-substituted amino
acids, condensed phosphoric acids, and ammonium salts or alkali
metal salts thereof.
[0032] The compound having at least one carboxyl group in a
molecule is preferably a nitrogen-containing polycarboxylic acid
having 1 to 4 nitrogen atoms And 9 to 6 carboxyl groups in a
molecule, and specifically includes, for example, alkylimimo
polycarboxylic acids which may have a hydroxyl group such as
hydroxyethyliminodiacetic acid [HIDA] and iminodiacetic acid [IDA];
nitrilopolycarboxylic acids such as nitrilotriacetic acid [NTA] and
nitrilotripropionic acid [NTP]; mono- or polyalkylene polyamine
polycarboxylic acids which may have a hydroxyalkyl group, a
hydroxyaryl group or a hydroxyaralkyl group such as ethylendiamine
tetraacetic acid [EDTA], ethylendiamine diacetic acid [EDDA],
ethylendiamine dipropionic acid dihydrochloric acid [EDDP],
hydroxyethylethylenediamine triacetic acid [EDTA-OH],
1,6-hexamethylenediamine-N,N,N',N'-tetraacetic acid [HDTA],
triethylenetetramine hexaacetic acid [TTHA],
diethylenetriamine-N,N,N',N'',N''-pentaacetic acid [DTPA] and
N,N-bis(2-hydroxybenzyl)ethylenediamine-N,N-diacetic acid [HBED];
polyaminoalkane polycarboxylic acids such as diaminopropane
tetraacetic acid [Methyl-EDTA] and
trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid [CyDTA];
polyaminoalkanol polycarboxylic acids such as diaminopropanol
tetraacetic acid [DPTA-OH]; and hydroxyalkylether polyamine
polycarboxylic acids such as glycolether diamine tetraacetic acid
[GEDTA].
[0033] The compound having at least one phosphonic acid group in a
molecule includes, for example, a nitorogen-containing
polyphosphonic acid having 1 to 6 nitrogen atoms and 1 to 8
phosphonic acid groups in a molecule such as
alkylaiminopoly(alkylphosphonic acid), mono- or
polyalkylenepolyamine poly(alkylphosphonic acid) and
nitrilopoly(alkylphosphonic acid); arylphosphonic acid;
alkylenepolyphosphonic acid; and alkanepolyphosphonic acid which
may have a hydroxyl group.
[0034] The compound having at least one phosphonic acid group is
more preferably a compound represented by the following general
formula [1], [2] or [4]: ##STR1## (wherein, X represents a hydrogen
atom or a hydroxyl group, and R.sup.1 represents a hydrogen atom or
an alkyl group); ##STR2## (wherein, Q represents a hydrogen atom,
or --R.sup.3--PO.sub.3H.sub.2 group, R.sup.2 and R.sup.3 represent
each independently an alkylene group, and Y represents a hydrogen
atom, --R.sup.3--PO.sub.3H.sub.2 group or a group represented by
the following general formula [3]): ##STR3## (wherein, Q and
R.sup.3 are same to the above); ##STR4## (wherein, R.sup.4 and
R.sup.5 represent each independently a lower alkylene group, n
represents an integer of 1 to 4, Z.sup.1 to Z.sup.4 and at least 4
of n.times.Z.sup.5 represent an alkyl group having a phosphonic
acid group, and the rest represents an alkyl group.)
[0035] In the general formula [1], the alkyl group represented by
R.sup.1 is preferably a straight chained or a branched one having 1
to 10 carbon atoms, and includes, for example, a methyl group, an
ethyl group, a n-propyl group, an isopropyl group, a n-butyl group,
an isobutyl group, a tert-butyl group, a sec-butyl group, a
n-pentyl group, an isopentyl group, a tert-pentyl group, a
1-methylpentyl group, a n-hexyl group, an isohexyl group, a heptyl
group, an octyl group, a nonyl group and a decyl group.
[0036] In the general formulae [2] and [3], each of the alkylene
groups represented by R.sup.1 and R.sup.2 is preferably a straight
chained or a branched one having 1 to 10 carbon atoms, and
includes, for example, a methylene group, an ethylene group, a
propylene group, a methylethylene group, an ethylmethylene group, a
butylene group, a 2-methylpropylene group, an ethylethylene group,
a pentylene group, a 2,2-dimethylpropylene group, a
2-ethylpropylene group, a hexylene group, a heptylene group, an
octylene group, a 2-ethylhexylene group, a nonylene group and a
decylene group.
[0037] In the general formula [4], the lower alkylene group
represented by R.sup.4 or R.sup.5 is preferably a straight chained
or a branched one having 1 to 4 carbon atoms, and specifically
includes, for example, a methylene group, an ethylene group, a
propylene group, a methylmethylene group, a methylethylene group,
an ethylmethylene group, a butylene group, a methylpropylene group
and an ethylethylene group.
[0038] Further, in the general formula [4], the alkyl group and the
alkyl group of the alkyl group having a phosphonic acid group
represented by Z.sup.1 to Z.sup.5 is preferably a straight chained
or a branched one having 1 to 4 carbon atoms, and includes, for
example, a methyl group, an ethyl group, a n-propyl group, an
isopropyl group, a n-butyl group, an isobutyl group, a sec-butyl
group and a tert-butyl group. The number of phosphonic acid group
in these alkyl groups is generally 1 to 2, and preferably 2.
[0039] Among them, a compound in which all of Z.sup.1 to Z.sup.4
and n.times.Z.sup.5 are alkyl groups having a phosphonic acid group
in the above general formula [4] is preferable, due to a high
ability to form a complex with metallic impurities. Further, n in
the above general formula [4] is preferably an integer of 1 to 2,
from the viewpoint of easiness in production.
[0040] Specific examples of the compound having at least one
phosphonic acid group in a molecule to be used in the present
invention include, for example, alkylaminopoly(alkylphosphonic
acid) such as ethylaminobis(methylenephosphonic acid) and
dodecylaminobis(methylenephosphonic acid); mono- or
polyalkylenepolyamine poly(alkylphosphonic acid) such as
ethylenediaminebis(methylenephosphonic acid) [EDDPO],
ethylenediamine tetrakis(ethylenephosphonic acid), ethylenediamine
tetrakis(methylenephosphonic acid) [EDTPO], hexamethylenediamine
tetrakis(methylenephosphonic acid), isopropylenediamine
bis(methylenephosphonic acid),
isopropylenediaminetetra(methylenephosphonic acid), propanediamine
tetra(ethylenephosphonic acid) [PDTMP],
diaminopropanetetra(methylenephosphonic acid) [PDTPO],
diethylenetriamine penta(ethylenephosphonic acid) [DEPPO],
diethylenetriamine penta(methylenephosphonic acid) [DETPPO],
triethylenetetramine hexa(ethylenephosphonic acid) [TETHP] and
triethylenetetramine hexa(methylenephosphonic acid) [TTHPO];
nitrilopoly(alkylphosphonic acid) such as
nitrilotris(methylenephosphonic acid) [NTPO]; arylphosphonic acids
such as phenylphosphonic acid; alkylenepolyphosphonic acids such as
alkylenediphosphonic acid and (for example, methylenediphosphonic
acid); alkanepolyphosphonic acid such as alkanediphosphonic acids
which may have a hydroxyl group (for example,
ethylidenediphosphonic acid, 1 hydroxyethylidene-1,1'-diphosphonic
acid [HEDPO], 1-hydroxypropylidene-1,1'-diphosphonic acid and
1-hydroxybutylidene-1,1'-diphosphonic acid).
[0041] The N-substituted amines include, for example,
dihydroxyethylglycin [DHEG] and N-acetylglycin, and the condensated
phosphoric acids include, for example, tripolyphosphoric acid and
hexametaphosphoric acid.
[0042] Among the complexing agents according to the present
invention as described above, a compound having at least one
phosphonic acid group in a molecule is preferable. Among those
compounds, nitrogen-containing polyphosphonic acids having 1 to 6
nitrogen atoms and 1 to 8 phosphonic acid groups in a molecule are
more preferable and an alkane polyphosphonic acid which may have a
hydroxyl group are more preferable, and a mono- or
polyalkylenepolyamine poly(alkylphosphonic acid), a
nitrilopoly(alkylphosphonic acid) and an alkane polyphosphonic acid
which may have a hydroxyl group are perticularly preferable,
because of superior solubility in water and complexation
coefficients and the like.
[0043] Further, among the compounds represented by the above
general formulae [1], [2] and [4], a compound represented by the
general formula [2] and a compound represented by the general
formula [4] are preferable, and a compound represented by the
general formula [4] is particularly preferable.
[0044] More specifically, preferable examples of the complexing
agent include ethylenediamine bis(methylenephosphonic acid)
[EDDPO], ethylenediamine tetrakis(ethylenephosphonic acid),
ethylenediamine tetrakis(methylenephosphonic acid) [EDTPO],
hexamethylenediamine tetrakis(methylenephosphonic acid),
isopropylenediamine bis(methylenephosphonic acid),
isopropylenediamine tetra(methylenephosphonic acid), propanediamine
tetra(ethylenephosphonic acid) [PDTMP], diaminopropane
tetra(methylenephosphonic acid) [PDTPO], diethylenetriamine
penta(ethylenephosphonic acid) [DEPPO], diethylenetriamine
penta(methylenephosphonic acid) [DETPPO], triethylenetetramine hexa
(ethylenephosphonic acid) [TETHP], triethylenetetramine
hexa(methylenephosphonic acid) (TTHPO),
nitrilotris(methylenephosphonic acid) [NTPO],
ethylidenediphosphonic acid, 1-hydroxyethylidene-1,1'-diphosphonic
acid [HEDPO], 1-hydroxypropylidene-1,1'-diphosphonic acid and
1-hydroxybutylidene-1,1'-diphosphonic acid.
[0045] The complexing agent according to the present invention may
be used alone or in combination of two or more kinds.
[0046] The complexing agent according to the present invention is
contained to capture and remove metallic impurities which are
adhered to and remain on a surface of substrate, in particular, a
surface of semiconductor substrate with metallic wiring provided
thereon, which has been subjected to a polishing treatment, an
etching treatment, a CMP treatment or the like. Metallic impurities
include, for example, those derived from a transition metal such as
iron (Fe), nickel (Ni) and copper (Cu); and an alkali earth metal
such as calcium (Ca) and magnesium (Mg), and are, for example,
these metals themselves, hydroxides thereof or oxides thereof. The
complexing agents according to the present invention can remove the
metallic impurities by forming a stable complex ion with these
metals.
[0047] The organic acid according to the present invention is an
organic acid having at least one, preferably 1 to 3, and more
preferably 2 to 3 carboxyl groups, and further may have 1 to 3
hydroxyl groups and/or 1 to 3 amino groups.
[0048] Specific examples of the organic acid according to the
present invention include, for example, monocarboxylic acids such
as formic acid, acetic acid, propionic acid, butyric acid,
n-valeric acid, 1-methylbutyric acid, 2-methylbutyric acid, caproic
acid, enanthic acid, caprylic acid, trans-2-methyl-2-pentenoic
acid, phenylacetic acid, 3-phenylvaleric acid, 4-phenylvaleric
acid, benzoic acid, .omega.-cyclohexylbutyric acid,
.alpha.-naphthaleneacetic acid and diphenylacetic acid;
dicarboxylic acids such as oxalic acid, malonic acid, succinic
acid, glutaric acid, adipic acid, pimelic acid, maleic acid,
fumaric acid, phthalic acid, suberic acid, 2-n-butylmalonic acid,
citraconic acid, mesaconic acid, isophthalic acid and terephthalic
acid; tricarboxylic acids such as trimellitic acid, tricarbarylic
acid and benzenetricarboxylic acid; oxycarboxylic acids such as
oxymonocarboxylic acid [for example, hydroxyacetic acid,
hydroxybutyric acid, lactic acid and salicylic acid],
oxydicarboxylic acids [for example, malic acid, tartaric acid and
tartronic acid], oxytricarboxylic acids [for example, citric acid];
and aminocarboxylic acids such as aspartic acid and glutamic
acid.
[0049] Among the above organic acids, dicarboxylic acids and
oxydicarboxylic acids are preferable.
[0050] Further, among the oxycarboxylic acids, oxydicarboxylic
acids and oxytricarboxylic acids are more preferable.
[0051] More specifically, oxalic acid, malonic acid, fumaric acid,
malic acid, tartaric acid and citric acid are particularly
preferable.
[0052] The organic acid according to the present invention may be
used alone or in combination of two or more kinds.
[0053] It is supposed that the organic acid according to the
present invention dissolves a metal oxide or a metal hydroxide of
Fe or Al though slightly, and formation of a metal complex between
a metal ion generated by dissolution and a complexing agent results
in a shift of the equilibrium towards more metal dissolution,
improving dissolving power of the organic acid for metal, and thus
enabling to remove a metal adsorbed on or adhered to a surface of
substrate.
[0054] The cleaning agent for a substrate of the present invention
(hereinafter abbreviated as "a cleaning agent of the present
invention") contains an organic acid and/or a complexing agent and
an organic solvent according to the present invention, in
particular, the cleaning agent containing all of three components
of an organic acid, a complexing agent and an organic solvent is
preferable. Further, the cleaning agent of the present invention is
usually in a state of solution, preferably an aqueous solution, and
prepared by dissolving the organic acid and/or the complexing agent
and the organic solvent according to the present invention as
described above in water.
[0055] When concentration of the organic solvent according to the
present invention to be used is too low, the carbon defect cannot
be sufficiently removed. On the contrary, too much amount of the
organic solvent according to the present invention to be used
disturbs complexing agent, organic acid, surfactant or the like to
exhibit performances described above sufficiently, causing a
problem that the removal effect for metal impurities or particles
is lowered, and is not preferable from the viewpoint of cost.
[0056] Further, when concentration of the organic acid according to
the present invention or the complexing agent according to the
present invention to be used is too low, the cleaning effect
becomes insufficient, and sometimes very weak in the case when a
surface of substrate is unexpectedly heavily contaminated. On the
other hand, a too high concentration of the organic acid according
to the present invention to be used does not influence the cleaning
effect, but is not preferable from the viewpoint of cost. Further,
a too high concentration of the complexing agent according to the
present invention to be used does not influence the cleaning
effect, but leads to a harmful carbon contamination on a surface of
semiconductor substrate, which causes a problem in electric
characteristics, and is not preferable from the viewpoint of
cost.
[0057] Usually, the organic acid according to the present invention
is used in a concentration range so that a ratio of the organic
acid to the total amount of the cleaning agent becomes, in the
lower limit, usually not lower than 0.05% by weight, preferably not
lower than 0.025% by weight, more preferably not lower than 0.5% by
weight, further more preferably not lower than 1% by weight, and in
the upper limit, usually not higher than 50% by weight, preferably
not higher than 40% by weight, more preferably not higher than 30%
by weight, further more preferably not higher than 10% by
weight.
[0058] The complexing agent according to the present invention is
used in a concentration range so that a ratio of the complexing
agent to the total amount of the cleaning agent becomes, in the
lower limit, usually not lower than 0.01% by weight, preferably not
lower than 0.025% by weight, more preferably not lower than 0.05%
by weight, further more preferably not lower than 0.1% by weight,
and in the upper limit, usually not higher than 30% by weight,
preferably not higher than 10% by weight, more preferably not
higher than 5% by weight, further more preferably not higher than
1% by weight.
[0059] The organic solvent according to the present invention is
used in a concentration range so that a ratio of the organic
solvent to the total amount of the cleaning agent becomes, in the
lower limit, usually not lower than 0.05% by weight, preferably not
lower than 0.1% by weight, more preferably not lower than 0.5% by
weight, further more preferably not lower than 1% by weight, and in
the upper limit, usually not higher than 50% by weight, preferably
not higher than 40% by weight, more preferably not higher than 20%
by weight, further more preferably not higher than 10% by
weight.
[0060] A method for dissolving the organic acid and/or the
complexing agent and the organic solvent according to the present
invention in water is not particularly limited so long as a
solution finally containing these components can be prepared.
[0061] Specifically, the method includes, for example, (1) a method
of directly adding the organic acid and/or the complexing agent and
the organic solvent according to the present invention to water,
and dissolving them by stirring, (2) a method of mixing a solution
containing the organic acid and/or a solution containing the
complexing agent according to the present invention and a solution
containing the organic solvent according to the present invention,
each prepared by separately dissolving the organic acid and/or the
complexing agent according to the present invention and the organic
solvent according to the present invention in water, or if
necessary, (3) a method of mixing a solution containing the organic
acid and the complexing agent each according to the present
invention prepared by directly adding the organic acid and the
complexing agent each according to the present invention to water
and dissolving by stirring, with a solution containing the organic
solvent according to the present invention prepared by separately
dissolving the organic solvent in water, (4) a method of mixing a
solution containing the organic solvent and the complexing agent
each according to the present invention prepared by directly adding
the organic solvent and the complexing agent each according to the
present invention to water and dissolving by stirring, with a
solution containing the organic acid according to the present
invention prepared by separately dissolving the organic acid in
water, and (5) a method of mixing a solution containing the organic
acid and the organic solvent each according to the present
invention prepared by directly adding the organic acid and the
organic solvent each according to the present invention to water
and dissolving by stirring, with a solution containing the
complexing agent according to the present invention prepared by
separately dissolving the complexing agent in water.
[0062] The cleaning agent of the present invention thus prepared is
preferably subjected to a treatment such as filtration before use.
Water to be used here is preferably one purified to some extent by
a treatment such as distillation and ion exchange, and more
preferably so-called ultra pure water used in the art.
[0063] The cleaning agent of the present invention is preferably
acidic, and pH value thereof is, in the lower limit, usually not
lower than 0.5, preferably not lower than 0.7, more preferably not
lower than 1, further more preferably not lower than 2, and in the
upper limit, usually not higher than 6.5, preferably not lower than
5, further more preferably not higher than 3.
[0064] In the cleaning agent of the present invention, besides the
organic acid, the complexing agent and the organic solvent
according to the present invention as described above, various
kinds of auxiliary components may be included within a range not
impairing the effects of the present invention.
[0065] Such auxiliary components include those usually used in the
art, and specifically, for example, a reducing agent and a metal
corrosion inhibitor which are used for the purposes of protecting
Cu of wiring and preventing corrosion of Cu, and a surfactant which
is used for the purpose of improving wetting property of the
cleaning agent to a surface of semiconductor to enhance the
cleaning effect.
[0066] The reducing agent includes, for example, hydrazine and
derivatives thereof, ascorbic acid and formalin. These reducing
agents may be used alone or in an appropriate combination of two or
more kinds.
[0067] Further, the metal corrosion inhibitor includes, as
described above, aromatic compounds such as benzotriazole or
derivatives thereof (for example, JP-A-51-29338, JP-A-1-195292 and
JP-A-10-265979) and benzimidazoles (for example, JP-A-7-79061);
cyclic compounds such as mercaptoimidazole and mercaptothiazole
(for example, JP-A-2000-87268 and JP-A-2000-282096); aliphatic
alcohol type compounds having a mercapto group in a molecule where
a carbon to which a mercapto group is bonded and a carbon to which
a hydroxyl group is bonded links together adjacently, such as
mercaptoethanol and mercaptoglycerol (for example,
JP-A-2000-273663); amino acids having a thiol group in a molecule
such as cysteine and N-acetylcysteine (for example,
JP-A-2003-13266); and thioureas. These surfactants may be used
alone or in an appropriate combination of two or more kinds.
[0068] The surfactant includes, for example, nonionic surfactants
having a polyoxyalkylene group in a molecule; anionic surfactants
having a group selected from sulfonic acid group, carboxyl group,
phosphonic acid group, sulfoxyl group and phosphonoxyl group in a
molecule; amphoteric surfactants such as alkylbetaine derivatives,
imidazoliniumbetaine derivatives, sulfobetaine derivatives,
aminocarboxylic acid derivatives, imidazoline derivatives and amine
oxide derivatives.
[0069] Nonionic surfactants having a polyoxyalkylenegroup in a
molecule include, for example, polyoxyalkylene alkylether and
polyoxyalkylene polyalkylarylether. More specifically, nonionic
surfactants include, for example, nonionic surfactants having a
polyoxyehylene group in a molecule such as polyoxyethylene
alkylether and polyoxyethylene alkylphenylether; nonionic
surfactants having a polyoxypropylene group in a molecule such as
polyoxypropylene alkylether, polyoxypropylene alkylphenylether;
nonionic surfactants having a polyoxyehylene group and a
polyoxypropylene group in a molecule such as
polyoxyethylenepolyoxypropylene alkylether and
polyoxyethylenepolyoxypropylene alkylphenylether.
[0070] Among them, particularly preferable nonionic surfactants are
polyoxyalkylene alkylethers. More specifically, nonionic
surfactants having a polyoxyethylene group in a molecule such as
polyoxyethylene alkylether and nonionic surfactants having a
polyoxyethylene and a polyoxypropylene groups in a molecule such as
polyoxyethylene polyoxypropylene alkylether are particularly
preferable.
[0071] Further, among polyoxyalkylene alkylethers having a
polyoxyethylene and a polyoxypropylene groups in a molecule, a
compound represented by the formula: CH.sub.3 (CH.sub.2).sub.k--O--
(CH.sub.2 CH.sub.2O).sub.1--(CH.sub.2CH(CH.sub.3)O).sub.m--H
(wherein, k=7 to 20, preferably 11, 1=4 to 20, preferably 13 to 14,
m=1 to 6, preferably 1 to 2) is particularly preferable.
[0072] More specifically, methanol, ethanol, isopropyl alcohol,
2-methoxyethanol, 2-(2-butoxyethoxy)ethanol, ethyleneglycol,
diethyleneglycol monomethylether, acetone, acetonitrile and
polyoxyethylene polyoxypropylene alkylether (particularly
CH.sub.3(CH.sub.2).sub.11--O--(CH.sub.2CH.sub.2O).sub.13-14--(CH.sub.2CH(-
CH.sub.3)O).sub.1-2--H) are preferable. Among them, methanol,
ethanol, isopropyl alcohol, 2-methoxyethanol, ethyleneglycol,
diethyleneglycol monomethylether, acetonitrile and polyoxyethylene
polyoxypropylene alkylether [particularly CH.sub.3
(CH.sub.2).sub.11--O--(CH.sub.2CH.sub.2O).sub.13-14--(CH.sub.2CH(CH.sub.3-
)O).sub.1-2--H] are more preferable.
[0073] Anionic surfactants having a group selected from sulfo
group, carboxylic group, phosphonic acid group, sulfoxyl group and
phosphonoxyl group in a molecule include, for example, anionic
surfactants having a sulfo group in a molecule such as
alkylsulfonic acid, alkylbenzenesulfonic acid, alkylnaphthalene
sulfonic acid, and salts thereof (for example, salts of an alkali
metal such as sodium and potassium; and ammonium salt); anionic
surfactants having a carboxyl group in a molecule such as
alkylcarboxylic acid, alkylbenzenecarboxylic acid,
alkylnaphthalenecarboxylic acid, and salts thereof (for example,
salts of an alkali metal such as sodium and potassium; and ammonium
salt); anionic surfactants having a phosphonic acid group in a
molecule such as alkylphosphonic acid, alkylbenzenephosphonic acid,
alkylnaphthalenephosphonic acid, and salts thereof (for example,
salts of an alkali metal such as sodium and potassium; and ammonium
salt); anionic surfactants having a sulfoxyl group in a molecule
such as alkyl sulfate, alkylbenzene sulfate, polyoxyethylene alkyl
sulfate, polyoxyethylene alkylbenzene sulfate, polyoxyethylene
alkylnaphthalene sulfate, and salts thereof (for example, salts of
an alkali metal such as sodium and potassium; and ammonium
salt).
[0074] Among them, anionic surfactants having a sulfo group or a
sulfoxyl group in a molecule are particularly preferable. More
specifically, anionic surfactants having a carboxyl group in a
molecule such as alkylbenzenesulfonic acid and anionic surfactants
having a sulfoxyl group in a molecule such as polyoxyethylenealkyl
sulfate are particularly preferable.
[0075] Among the above mentioned surfactants, nonionic surfactants
and anionic surfactants are preferable.
[0076] These compounds may be used alone or in combination of two
or more kinds.
[0077] These auxiliary components may be used in such a range of
concentration that they are usually used in the art. For instance,
the reducing agent may be used in any amount, so long as the
reducing agent can prevent oxidation of metallic Cu. The lower
limit thereof is usually not less than 0.01% by weight, preferably
not less than 0.05% by weight, more preferably not less than 0.07%
by weight to the total amount of the cleaning agent, and the upper
limit thereof is usually not more than 5% by weight, preferably not
more than 1% by weight, more preferably not more than 0.5% by
weight to the total amount of the cleaning agent. Further, the
metal corrosion inhibitor can be used in any amount, so long as the
inhibitor can suppress dissolving power of the cleaning agent for
Cu by forming a weak bond with metallic Cu. The lower limit thereof
is usually not less than 0.01% by weight, preferably not less than
0.05% by weight, more preferably not less than 0.1% by weight to
the total amount of the cleaning agent, and the upper limit thereof
is usually not more than 5% by weight, preferably not more than 1%
by weight, more preferably not more than 0.5% by weight to the
total amount of the cleaning agent. Also, the surfactant can be
used in any amount, so long as the surfactant can lower down
surface tension of the cleaning agent. The lower limit thereof is
usually not less than 0.0001% by weight, preferably not less than
0.001% by weight, more preferably not less than 0.005% by weight to
the total amount of the cleaning agent, and the upper limit thereof
is usually not more than 1% by weight, preferably not more than
0.5% by weight, more preferably not more than 0.1% by weight to the
total amount of the cleaning agent.
[0078] In this connection, in the present invention, use of the
following compounds is not desirable: compounds which dissolve the
metal corrosion inhibiting film (particularly a Cu-BTA film) formed
on the substrate surface by decreasing pH value of the cleaning
agent (for example, an inorganic acid such as hydrochloric acid,
nitric acid, sulfuric acid, phosphoric acid and hydrofluoric acid),
compounds which oxidize the metal corrosion inhibiting film (for
example, an oxidizing agent such as phosphorus acid), and compounds
which cause a defective Cu wiring or dissolution of Cu by
specifically reacting with Cu ion to form a complex with Cu (for
example, phenanthroline or derivatives thereof).
[0079] The cleaning agent of the present invention shows an
effective cleaning effect even at room temperature, but may be used
after properly warmed up, because the removal effect for fine
particles is rather larger at a higher temperature. When warmed up,
the lower limit of the temperature is usually not lower than
30.degree. C., preferably not lower than 35.degree. C., more
preferably not lower than 40.degree. C., and the upper limit
thereof is usually not higher than 80.degree. C., preferably not
higher than 70.degree. C., and more preferably not higher than
60.degree. C.
[0080] A method for cleaning a surface of substrate of the present
invention may be treating the surface of semiconductor with the
cleaning agent of the present invention as described above.
[0081] As a method for treating a surface of substrate with the
cleaning agent of the present invention, any method may be used so
long as the cleaning agent of the present invention can contact
with a surface of substrate, and methods which are commonly
employed in the art and already known are used.
[0082] Specifically, those includes, for example, a method where
the cleaning agent of the present invention is simply coated on a
surface of substrate, a method where a substrate is dipped in the
cleaning agent of the present invention (dipping treatment), a
method where the cleaning agent of the present invention is
sprinkled like a shower or sprayed on a surface of substrate
(single-wafer-based treatment).
[0083] Moreover, in the present invention, particles, metallic
impurities and a carbon defect can be more effectively removed by
using a physical cleaning in combination in the cleaning.
[0084] Specific methods of the combined use include subjecting a
surface of substrate to a physical cleaning process in the presence
of the cleaning agent of the present invention.
[0085] In the above-described method, a method for providing the
cleaning agent of the present invention includes, for example, a
method to apply a physical cleaning process in a state in which a
cleaning agent of the present invention exist specifically by the
above described method for cleaning the surface of substrate
(coating method, dipping treatment and single-wafer-based
treatment). Further, the physical cleaning (process) includes, for
example, brush-scrub cleaning where a surface of substrate is
cleaned with a brush made of polyvinyl alcohol rotating at a high
speed and megasonic cleaning where high frequency wave is used.
[0086] A more specific technique when physical cleaning is used in
combination includes, for example, a method to apply a physical
cleaning after providing a cleaning agent of the present invention
on the surface of a semiconductor by coating said cleaning agent on
the surface of a semiconductor, a method to apply a physical
cleaning after providing a cleaning agent of the present invention
on the surface of a semiconductor by dipping the semiconductor in
said cleaning agent, then taking it out of said cleaning agent, a
method to apply a physical cleaning while a semiconductor is dipped
in a cleaning agent of the present invention, a method to apply a
physical cleaning after providing a cleaning agent of the present
invention on the surface of a semiconductor by showering said
cleaning agent on the surface of the semiconductor, or a method to
apply a physical cleaning while a cleaning agent of the present
invention is showered on the surface of a semiconductor.
[0087] Since the cleaning agent of the present invention has not
only capability of removing a carbon defect, but also capabilities
of removing particles and metallic impurities, not only a carbon
defect, but also particles and metallic impurities which remain on
or adhered to a surface of substrate can be removed (cleaned) at
the same time, by treating the surface of substrate with the
cleaning agent of the present invention.
[0088] Thus, the surface of substrate can be sufficiently cleaned
only by using the cleaning agent of the present invention, but the
surface of substrate may be subjected to the cleaning method using
the cleaning agent of the present invention as described above,
then further cleaned with a cleaning agent for a substrate which is
already known.
[0089] By treating in such way, it becomes possible to clean a
surface of substrate with high precision. In this connection, as
the already known cleaning agent for a substrate to be used,
cleaning agents usually used in the art can be used, as disclosed,
for instance, in JP-A-4-130100, JP-A-5-263275, JP-A-6-112646,
JP-A-6-287774, JP-A-7-79061, JP-A-7-166381, JP-A-7-267933,
JP-A-7-292483, JP-A-7-54169, JP-A-10-26832, JP-A-10-72594,
JP-A-10-251867, JP-A-11-50275, JP-A-2000-8185 and JP-A-2002-20787.
Among them, a so-called acidic cleaning agent is preferable.
[0090] The cleaning agent of the present invention can be used, for
example, for a substrate of semiconductor such as a so-called
silicone wafer and a semiconductor of compounds (for example GaAs
and GaP), a printed circuit board such as a polyimide resin, and a
glass substrate for LCD and PDP, and is particularly useful for a
substrate of semiconductor.
[0091] Further, among these substrates, the cleaning agent of the
present invention is useful for a substrate which is provided with
wiring of metals such as copper, silver, aluminum, tungsten-plug,
chrome and gold on the surface thereof, and among them, for a
substrate which is provided with copper or silver wiring, and
particularly for a substrate which is provided with copper wiring,
and is most useful for a substrate of semiconductor which is
provided with copper wiring on the surface thereof.
EFFECT OF THE INVENTION
[0092] By using the cleaning agent of the present invention, fine
particles (particles) and impurities derived from various kinds of
metals (metallic impurities) present on a surface of substrate can
be effectively removed without causing corrosion or oxidation of
metallic wiring, especially copper wiring provided on the substrate
surface, and further, a carbon defect present on the substrate
surface can also be removed at the same time without removing a
metal corrosion inhibitor--Cu film, in particular, a Cu-BTA
film.
[0093] Hereinafter, the present invention will be explained in
detail by illustrating Examples and Comparative Examples, but the
present invention should not be construed to be limited thereby in
the least.
[0094] A metallic Cu deposited wafer, a wafer provided with a
Cu-BTA film, a wafer contaminated with a carbon defect and a wafer
contaminated with a metal used in the present Examples and
Comparative Examples are prepared according to the following
methods and used, and a thickness of Cu film on a surface of the
metallic Cu deposited wafer, a thickness of Cu-BTA film on a
surface of the wafer provided with a Cu-BTA film, and an adsorption
amount (a remaining metal concentration) of metal (Fe atom, Al atom
and Cu atom) adsorbed and remaining on a surface of the wafer
contaminated with a metal were measured according to the following
methods, respectively.
[Metallic Cu Deposited Wafer]
[0095] The metallic Cu deposited wafer was obtained by depositing
metallic Cu on a surface of 4-inch silicone wafer by a sputtering
method.
[0096] In this connection, it was confirmed by the method shown
below that a thickness of copper on a surface of said metallic Cu
deposited wafer was 1,000 nm.
[Wafer Provided with a Cu-BTA Film]
[0097] The wafer provided with a Cu-BTA film was obtained by
oxidizing a Cu surface of the metallic Cu deposited wafer with 0.1%
H.sub.2O.sub.2 for 15 min, thereafter dipping in 1% aqueous BTA
solution for 20 min.
[0098] In this connection, it was confirmed by the method shown
below that a thickness of Cu-BTA film on a surface of said wafer
provided with a Cu-BTA film was 100 nm.
[Wafer Contaminated with a Carbon Defect]
[0099] The wafer contaminated with a carbon defect was obtained by
dipping the wafer provided with a Cu-BTA film in a saturated BTA
aqueous solution at 80.degree. C. for 40 min, then cooling the
wafer at 10.degree. C. under the nitrogen atmosphere.
[0100] In this connection, it was confirmed by direct measurement
using an Auger photoelectron spectroscopic analyzer that the carbon
defect was adsorbed and remaining on a Cu-BTA film of the wafer
surface.
[Wafer Contaminated with Metal]
[0101] The wafer contaminated with metal was obtained dipping a
6-inch silicone wafer, surface of which was oxidized to SiO.sub.2
by thermal oxidation, in 1 L of an aqueous slurry (a 0.1% hydrogen
peroxide aqueous containing 1% of silica) added with Fe ion so as
to be 0.1 ppm, 1 L of an aqueous slurry (a 0.1% hydrogen peroxide
containing 1% of silica) added with Al ion so as to be 0.1 ppm, or
1 L of an aqueous slurry (a 0.1% hydrogen peroxide containing 1% of
silica) added with Cu ion so as to be 0.1 ppm, each for 1 min,
respectively, then rinsing the wafer with flowing ultra pure water
for 10 min, followed by spin-drying.
[0102] In this connection, it was confirmed by the methods shown
below, that 5.times.10.sup.13 atom/cm.sup.2 of Fe (iron atom),
8.times.10.sup.13 atom/cm.sup.2 of Al (aluminum atom), or
3.times.10.sup.14 atom/cm.sup.2 of Cu (copper atom) was adsorbed
and remaining, respectively.
[Wafer Contaminated with Particles]
[0103] The wafer contaminated with particles was obtained by
dipping a wafer provided with a Cu-BTA film in an aqueous slurry of
3% alumina having an average particle diameter of 0.2 .mu.m for 1
min, then rinsing the wafer with flowing ultra pure water for 10
min, followed by spin-drying.
[0104] In this connection, it was confirmed by the method shown
below that about 8,000 particles per 6-inch wafer were adsorbed and
remaining on said wafer.
[Measuring Method for Thickness of Metallic Cu Film]
[0105] A wafer was divided into two halves, and a thickness of
metallic Cu film was measured by observing the cross section
thereof using an electron microscope.
[Measuring Method for Thickness of Cu-BTA Film]
[0106] A wafer was divided into two halves, and thickness of a
Cu-BTA film was measured by observing the cross section thereof
using a SEM (a scanning electron microscope).
[Measuring Method for Metal Concentration]
[0107] Metals (Fe, Al and Cu) adsorbed and remaining on the wafer
surface were dissolved with an aqueous solution of hydrofluoric
acid and nitric acid and recovered, then metal concentration in
said recovered solution was measured by an atomic absorption
spectrometry (a graphite furnace atomic absorption spectrometer).
Adsorption amounts (remaining metal concentrations) of metal atoms
(Fe atom, Al atom and Cu atom) were calculated based on the
measured values obtained.
[Measuring Method for Number of Particle]
[0108] Particles adsorbed and remaining on the wafer surface were
measured using a surface foreign material inspection apparatus (a
particle counter).
[0109] In this connection, in the present Examples and Comparative
Examples, all of %, ppm and ppb representing a concentration are
based on a weight ratio, unless otherwise noted. Further, all of
waters used were ultra pure water, and were used after confirming
that Fe, Al or Cu contained was not more than 0.01 ppb,
respectively.
EXAMPLES
Examples 1 to 44
[0110] Each of the wafer contaminated with a carbon defect, the
wafer provided with a Cu-BTA film and the metallic Cu deposited
wafer, which were prepared by the above-described methods, was
dipping in 1 L of each cleaning agent described in Table 1 at room
temperature for 5 hours. Thereafter, each of waters was taken out,
rinsed with ultra pure water for 10 min, and spin-dried.
[0111] As to the wafer contaminated with a carbon defect thus
treated, presence of the carbon defect adsorbed and remaining on
said wafer surface was confirmed to evaluate capability of removing
carbon defect, by direct measurement using an Auger photoelectron
spectroscopic analyzer.
[0112] And as to the wafer provided with a Cu-BTA film, thickness
of a Cu-BTA film on the wafer surface was measured to confirm an
influence (occurrence of dissolution and elution) on the Cu-BTA
film.
[0113] Further, as to the metallic Cu deposited wafer, color tone
of a Cu film surface on the wafer surface was checked by visual
examination to confirm oxidation of metallic Cu, and film thickness
of metallic Cu on the wafer surface was measured to confirm
occurrence of corrosion on the metallic Cu.
[0114] The results are shown in Table 1. TABLE-US-00001 TABLE 1
conc. conc. Ability for Thickness of Thickness Organic (% by
Complexing % by conc. removing Cu-BTA film Color tone of Cu film
Ex. acid WT) agent ( WT) Organic solvent (% by WT) pH carbon defect
(nm) of Cu film (nm) 1 oxalic acid 5 -- methanol 0.2 2
.largecircle. 100 metallic luster 1000 2 oxalic acid 5 -- ethanol
0.2 2 .largecircle. 100 metallic luster 1000 3 oxalic acid 5 --
isopropylalcohol 0.2 2 .largecircle. 90 metallic luster 1000 4
oxalic acid 5 -- 2-methoxyethanol 0.2 2 .largecircle. 100 metallic
luster 1000 5 oxalic acid 2 -- ethylene glycol 3 2 .largecircle.
100 metallic luster 1000 6 oxalic acid 5 -- acetone 0.2 2
.largecircle. 100 metallic luster 1000 7 oxalic acid 5 --
acetonitrile 0.2 2 .largecircle. 100 metallic luster 1000 8 citric
acid 5 -- methanol 0.2 2 .largecircle. 100 metallic luster 1000 9
citric acid 5 -- ethanol 0.2 2 .largecircle. 100 metallic luster
1000 10 citric acid 10 -- isopropylalcohol 0.2 2 .largecircle. 90
metallic luster 1000 11 citric acid 5 -- 2-methoxyethanol 5 2
.largecircle. 100 metallic luster 900 12 citric acid 5 -- ethylene
glycol 0.2 2 .largecircle. 100 metallic luster 1000 13 citric acid
25 -- acetone 10 1 .largecircle. 100 metallic luster 1000 14 citric
acid 5 -- acetonitrile 10 2 .largecircle. 100 metallic luster 900
15 -- EDTA 0.01 methanol 10 5 .largecircle. 100 metallic luster
1000 16 -- CyDTA 0.01 methanol 0.2 5 .largecircle. 100 metallic
luster 1000 17 -- CyDTA 0.01 ethylene glycol 10 5 .largecircle. 100
metallic luster 1000 18 -- HEDPO 5 methanol 0.2 1 .largecircle. 100
metallic luster 1000 19 -- HEDPO 0.1 acetonitrile 10 3
.largecircle. 100 metallic luster 1000 20 -- EDTPO 0.1
isopropylalcohol 0.2 3 .largecircle. 100 metallic luster 1000 21
acetic acid 5 EDTA 0.1 methanol 0.2 2 .largecircle. 90 metallic
luster 1000 22 oxalic acid 5 EDTA 0.1 methanol 10 2 .largecircle.
100 metallic luster 1000 23 oxalic acid 5 EDTA 0.1 acetone 0.2 2
.largecircle. 100 metallic luster 1000 24 oxalic acid 5 CyDTA 0.01
methanol 10 2 .largecircle. 90 metallic luster 1000 25 oxalic acid
2 CyDTA 0.01 ethylene glycol 0.2 2 .largecircle. 100 metallic
luster 1000 26 oxalic acid 5 HEDPO 0.1 methanol 0.2 2 .largecircle.
100 metallic luster 1000 27 oxalic acid 1 EDTPO 0.1
isopropylalcohol 10 2 .largecircle. 100 metallic luster 1000 28
oxalic acid 5 DEPPO 1 isopropylalcohol 0.2 2 .largecircle. 100
metallic luster 1000 29 citric acid 5 EDTA 0.01 methanol 0.2 2
.largecircle. 100 metallic luster 1000 30 citric acid 5 EDTA 0.01
ethanol 5 2 .largecircle. 100 metallic luster 1000 31 citric acid 5
EDTA 0.01 isopropylalcohol 0.2 1 .largecircle. 100 metallic luster
1000 32 citric acid 20 EDTA 0.01 acetone 0.2 1 .largecircle. 100
metallic luster 1000 33 citric acid 5 CyDTA 0.01 methanol 10 2
.largecircle. 90 metallic luster 1000 34 citric acid 5 CyDTA 0.01
ethylene glycol 0.2 2 .largecircle. 100 metallic luster 1000 35
citric acid 10 EDTA 0.01 diethylene glycol 0.2 2 .largecircle. 100
metallic luster 1000 36 citric acid 5 CyDTA 0.01 acetone 0.2 2
.largecircle. 90 metallic luster 1000 37 citric acid 5 EDTA 0.01
acetonitrile 0.2 2 .largecircle. 100 metallic luster 1000 38 citric
acid 5 TETHP 0.03 methanol 0.2 2 .largecircle. 100 metallic luster
1000 39 citric acid 20 HEDPO 5 methanol 8 1 .largecircle. 100
metallic luster 1000 40 citric acid 5 EDTPO 0.1 isopropylalcohol 10
2 .largecircle. 100 metallic luster 1000 41 citric acid 5 TETHP 0.1
2-methoxyethanol 0.2 2 .largecircle. 100 metallic luster 1000 42
citric acid 5 DEPPO 0.1 ethylene glycol 0.2 2 .largecircle. 100
metallic luster 1000 43 citric acid 10 DEPPO 5 diethylene glycol 5
1 .largecircle. 100 metallic luster 1000 44 citric acid 5 DEPPO 0.1
diethylene glycol 0.2 2 .largecircle. 100 metallic luster 1000
Comparative Examples 1 to 82
[0115] A wafer contaminated with a carbon defect, a wafer provided
with a Cu-BTA film and a metallic Cu deposited wafer were treated
in the same manner as in Examples 1 to 44 except that various
solutions described in Table 2 were used, thereafter similar
measurement and evaluation to those in Examples 1 to 44 were
carried out on each of these wafers.
[0116] The results are shown in Table 3. TABLE-US-00002 TABLE 2
Thick- Ability for ness of conc. conc. conc. removing Cu-BTA
Thickness Comp. (% by Complexing (% by (% by carbon film Color tone
of Cu film Ex. Organic acid WT) agent WT) Organic solvent WT) pH
defect (nm) of Cu film (nm) 1 -- -- -- 7 X 100 metallic luster 1000
2 hydrochloric acid 1 -- -- 1 -- 0 loss of luster 400 3 oxalic acid
5 -- -- 2 X 100 metallic luster 1000 4 citric acid 5 -- -- 2 X 100
metallic luster 1000 5 -- EDTA 0.01 -- 5 X 100 metallic luster 1000
6 -- CyDTA 0.01 -- 5 X 100 metallic luster 900 7 -- HEDPO 0.1 -- 3
X 100 metallic luster 1000 8 -- EDTPO 0.1 -- 3 X 100 metallic
luster 1000 9 -- -- methanol 0.2 7 X 100 metallic luster 1000 10 --
-- acetonitrile 0.2 7 X 100 metallic luster 1000 11 -- --
dimethylsulfoxide 0.2 7 X 100 metallic luster 1000 12 -- --
dimethylformamide 0.2 7 X 100 metallic luster 1000 13 phosphoric
acid 2 CyDTA 0.01 -- 2 X 100 metallic luster 950 14 acetic acid 4
HEDPO 0.1 -- 2 X 90 metallic luster 1000 15 oxalic acid 5 EDTA 0.01
-- 2 X 100 metallic luster 1000 16 oxalic acid 5 HEDPO 0.1 -- 2 X
100 metallic luster 1000 17 oxalic acid 5 CyDTA 0.01 -- 2 X 100
metallic luster 900 18 oxalic acid 5 EDTPO 0.1 -- 2 X 100 metallic
luster 1000 19 citric acid 5 EDTA 0.01 -- 2 X 100 metallic luster
1000 20 citric acid 5 HEDPO 0.1 -- 2 X 100 metallic luster 1000 21
citric acid 5 CyDTA 0.01 -- 2 X 100 metallic luster 1000 22 citric
acid 5 EDTPO 0.1 -- 2 X 90 metallic luster 1000 23 oxalic acid 5 --
dimethylsulfoxide 3 2 X 100 metallic luster 1000 24 oxalic acid 5
-- dimethylformamide 3 2 X 100 metallic luster 1000 25 oxalic ocid
5 -- .gamma.-butyrolactone 3 2 X 100 metallic luster 900 26 oxalic
ocid 5 -- tetrahydrofuran 3 2 X 100 metallic luster 1000 27 citric
acid 5 -- dimethylsulfoxide 3 2 X 100 metallic luster 1000 28
citric acid 5 -- dimethylformamide 3 2 X 100 metallic luster 1000
29 citric acid 5 -- .gamma.-butyrolactone 3 2 X 100 metallic luster
1000 30 citric acid 5 -- tetrahydrofuran 3 2 X 100 metallic luster
1000 31 -- EDTA 0.01 dimethylsulfoxide 3 5 X 90 metallic luster
1000 32 -- HEDPO 1 dimethylsulfoxide 3 3 X 90 metallic luster 1000
33 -- CyDTA 0.01 dimethylformamide 3 5 X 100 metallic luster 1000
34 -- HEDPO 5 dimethylformamide 3 3 X 100 metallic luster 1000 35
-- TETHP 0.03 dimethylformamide 3 3 X 100 metallic luster 1000 36
-- TETHP 0.03 .gamma.-butyrolactone 3 3 X 90 metallic luster 1000
37 -- EDTA 0.01 tetrahydrofuran 3 3 X 90 metallic luster 1000 38 --
CyDTA 0.01 methyl 3-methoxy 3 3 X 100 metallic luster 1000
propionate 39 phosphoric acid 2 EDTA 0.01 methanol 3 2 X 100
metallic luster 950 40 hydrochloric acid 1 EDTPO 0.1 methanol 3 1
-- 0 loss of luster 500 41 nitric acid 0.5 HEDPO 0.1 methanol 3 1
-- 0 loss of luster 400 42 nitric acid 0.5 EDTA 0.01 ethanol 3 1 --
0 loss of luster 400 43 nitric acid 0.5 TETHP 0.1 isopropylalcohol
3 1 -- 0 loss of luster 400 44 nitric acid 0.5 DEPPO 5
2-methoxyethanol 3 1 -- 0 loss of luster 400 45 nitric acid 0.5
EDTA 0.01 2-(2-butoxyethoxy) 3 1 -- 0 loss of luster 400 ethanol 46
nitric acid 0.5 EDTA 0.01 ethylene glycol 3 1 -- 0 loss of luster
500 47 nitric acid 0.5 EDTA 0.01 diethylene glycol 3 1 -- 0 loss of
luster 400 48 nitric acid 0.5 EDTA 0.01 acetone 3 1 -- 0 loss of
luster 500
[0117] TABLE-US-00003 TABLE 3 Thick- conc. Ability for ness of (%
conc. conc. removing Cu-BTA Thickness Comp. by Complexing (% by (%
by carbon film Color tone of Cu film Ex. Organic acid WT) agent WT)
Organic solvent WT) pH defect (nm) of Cu film (nm) 49 nitric acid
0.5 HEDPO 0.1 acetonitrile 3 1 -- 0 loss of luster 500 50
hydrofluoric acid 0.1 EDTA 0.01 methanol 3 1 -- 0 loss of luster
500 51 hydrofluoric acid 0.1 TETHP 0.01 ethanol 3 1 -- 0 loss of
luster 400 52 hydrofluoric acid 0.1 DEPPO 1 isopropylalcohol 3 1 --
0 loss of luster 400 53 hydrofluoric acid 0.1 EDTA 0.01
2-methoxyethanol 3 1 -- 0 loss of luster 400 54 hydrofluoric acid
0.1 DEPPO 0.1 2-(2-butoxyethoxy) 3 1 -- 0 loss of luster 400
ethanol 55 hydrofluoric acid 0.1 EDTA 0.01 ethylene glycol 3 1 -- 0
loss of luster 400 56 hydrofluoric acid 0.1 TETHP 0.03 diethylene
glycol 3 1 -- 0 loss of luster 400 57 hydrofluoric acid 0.1 EDTA
0.01 acetone 3 1 -- 0 loss of luster 400 58 hydrofluoric acid 0.1
EDTA 0.01 acetonitrile 3 1 -- 0 loss of luster 400 59 nitric acid
0.5 EDTA 0.01 dimethylsulfoxide 3 1 -- 0 loss of luster 400 60
nitric acid 0.5 TETHP 0.1 dimethylformamide 3 1 -- 0 loss of luster
400 61 nitric acid 0.5 TETHP 0.1 .gamma.-butyrolactone 3 1 -- 0
loss of luster 400 62 nitric acid 0.5 DEPPO 2 tetrahydrofuran 3 1
-- 0 loss of luster 400 63 nitric acid 0.5 EDTA 0.01 methyl
3-methoxy 3 1 -- 0 loss of luster 400 propionate 64 hydrofluoric
acid 0.1 CyDTA 0.01 dimethylsulfoxide 3 1 -- 0 loss of luster 500
65 hydrofluoric acid 0.1 EDTA 1 dimethylformamide 3 1 -- 0 loss of
luster 400 66 hydrofluoric acid 0.1 TETHP 0.1 .gamma.-butyrolactone
3 1 -- 0 loss of luster 400 67 hydrofluoric acid 0.1 EDTA 0.01
tetrahydrofuran 3 1 -- 0 loss of luster 400 68 hydrofluoric acid
0.1 EDTA 0.01 methyl 3-methoxy 1 -- 0 loss of luster 400 propionate
69 oxalic acid 5 EDTA 0.01 dimethylsulfoxide 3 2 X 100 metallic
luster 1000 70 oxalic acid 5 CyDTA 0.01 dimethylformamide 3 2 X 100
metallic luster 1000 71 citric acid 5 EDTA 0.01 dimethylsulfoxide 3
2 X 90 metallic luster 1000 72 citric acid 4 TETHP 0.1
dimethylsulfoxide 3 2 X 100 metallic luster 1000 73 citric acid 10
CyDTA 0.01 dimethylformamide 3 2 X 90 metallic luster 1000 74
citric acid 5 HEDPO 1 dimethylformamide 3 2 X 100 metallic luster
1000 75 citric acid 20 TTHA 0.01 .gamma.-butyrolactone 3 1 X 100
metallic luster 1000 76 citric acid 5 EDTA 0.1 tetrahydrofuran 3 2
X 90 metallic luster 1000 77 citric acid 5 HEDPO 0.5 methyl
3-methoxy 3 2 X 100 metallic luster 1000 propionate 78 citric acid
5 hexameta- 0.1 -- 2 X 100 metallic luster 1000 phosphoric acid 79
citric acid 10 ammonium 1 -- 2 -- 0 loss of luster 400 fluoride 80
citric acid 5 ammonium 0.1 -- 2 -- 0 loss of luster 400 fluoride 81
citric acid 5 ammonium 0.2 -- 2 -- 0 loss of luster 400 fluoride 82
citric acid 5 ammonium 0.2 -- 2 -- 0 loss of luster 400
fluoride
[0118] As apparent from Tables 1, 2 and 3, when the cleaning agents
of the present invention are used (Examples 1 to 44), followings
can be understood: (1) carbon defect can be well removed; (2) color
tone of a surface of Cu film on a wafer surface is not changed,
proving that the metallic Cu has not been oxidized; (3) thickness
of a Cu film shows little change, proving that the metallic Cu has
not been corroded; (4) thickness of a Cu-BTA film shows little
change, proving that the Cu-BTA film has been hardly removed.
[0119] On the contrary, it can be understood that a carbon defect
cannot be removed when an organic acid (Comparative Examples 2 to
4), a complexing agent (Comparative Examples 5 to 8) or an organic
solvent (Comparative Examples 9 to 12) is used alone, or when only
an organic acid and a complexing agent are used in combination
(Comparative Examples 13 to 22 and Comparative Examples 78 to
82).
[0120] Further, as apparent from a comparison between Examples 1 to
14 and Comparative Examples 23 to 30, a comparison between Examples
15 to 20 and Comparative Examples 31 to 38, and a comparison
between Examples 39 to 48 and Comparative Examples 69 to 77, it can
be understood respectively that a carbon defect cannot be removed
when a cleaning agent containing an organic solvent other than the
organic solvent according to the present invention is used.
Furthermore, as apparent from a comparison between Examples 21 to
44 and Comparative Examples 39 to 68, it can be also understood
that a carbon defect cannot be removed or a Cu-BTA film or a Cu
film is dissolved, when a cleaning agent containing an acid other
than the organic acid according to the present invention is
used.
[0121] As apparent from the above, it can be understood that a
carbon defect can be well removed without causing corrosion or
oxidation of Cu or further losing a Cu-BTA film, only when the
specified organic acid and/or the specified complexing agent and
the specified organic solvent according to the present invention
are used in combination.
Examples 45 to 76
[0122] Each of the wafers contaminated with metals prepared by the
above-described method was dipped in 1 L each of cleaning agents
described in Table 4, at room temperature for 1 hour. Thereafter,
the wafer was taken out, rinsed with ultra pure water for 10 min,
and spin-dried.
[0123] For the wafers contaminated with metals thus treated,
remaining metal concentrations (remaining Fe concentration,
remaining Al concentration, and remaining Cu concentration)
adsorbed and remaining on a surface of the wafer were measured, to
evaluate capability of removing metallic impurities.
[0124] The results are shown in Table 4. TABLE-US-00004 TABLE 4
remaining remaining remaining conc. Complex- conc. conc. Fe conc.
Al conc. Cu conc. Ex. Organic acid (% by WT) ing agent (% by WT)
Organic solvent (% by WT) pH (Fe atom/cm.sup.2) (Al atom/cm.sup.2)
(Cu atom/cm.sup.2) 45 citric acid 5 -- methanol 0.2 2 4 .times.
10.sup.13 9 .times. 10.sup.12 2 .times. 10.sup.12 46 acetic acid 5
-- methanol 0.2 2 6 .times. 10.sup.12 4 .times. 10.sup.12 4 .times.
10.sup.12 47 malonic acid 5 -- isopropylalcohol 5 3 7 .times.
10.sup.12 8 .times. 10.sup.12 3 .times. 10.sup.12 48 fumaric acid 5
-- 2-methoxyethanol 10 3 3 .times. 10.sup.12 2 .times. 10.sup.12 1
.times. 10.sup.13 49 malic acid 5 -- ethylene glycol 2 3 9 .times.
10.sup.12 5 .times. 10.sup.12 7 .times. 10.sup.12 50 tartaric acid
5 -- diethylene glycol 5 3 5 .times. 10.sup.12 9 .times. 10.sup.12
8 .times. 10.sup.12 monomethyl ether 51 oxalic acid 5 -- acetone
0.2 2 6 .times. 10.sup.12 7 .times. 10.sup.12 3 .times. 10.sup.12
52 oxalic acid 5 -- acetonitrile 0.2 2 1 .times. 10.sup.13 3
.times. 10.sup.12 9 .times. 10.sup.12 53 -- EDTA 0.01 methanol 0.2
5 4 .times. 10.sup.12 6 .times. 10.sup.12 8 .times. 10.sup.12 54 --
DEPPO 0.1 methanol 0.2 3 4 .times. 10.sup.12 1 .times. 10.sup.11 5
.times. 10.sup.11 55 -- EDTPO 5 isopropylalcohol 0.2 2 6 .times.
10.sup.11 4 .times. 10.sup.11 6 .times. 10.sup.11 56 -- CyDTA 0.01
2-methoxyethanol 0.2 5 3 .times. 10.sup.12 7 .times. 10.sup.12 4
.times. 10.sup.12 57 -- HEDPO 0.1 2-methoxyethanol 0.2 5 4 .times.
10.sup.11 2 .times. 10.sup.12 7 .times. 10.sup.11 58 -- HEDPO 0.1
ethylene glycol 0.2 3 2 .times. 10.sup.12 1 .times. 10.sup.11 3
.times. 10.sup.11 59 -- DETPPO 5 diethylene glycol 0.2 2 4 .times.
10.sup.11 6 .times. 10.sup.11 4 .times. 10.sup.11 monomethyl ether
60 -- DETPPO 0.1 diethylene glycol 0.2 3 2 .times. 10.sup.11 4
.times. 10.sup.11 4 .times. 10.sup.11 monomethyl ether 61 -- HEDPO
0.1 acetone 5 3 4 .times. 10.sup.11 3 .times. 10.sup.11 4 .times.
10.sup.11 62 -- PTDMP 0.1 acetone 0.2 3 2 .times. 10.sup.11 2
.times. 10.sup.11 9 .times. 10.sup.11 63 -- EDTA 0.1 acetonitrile 5
5 7 .times. 10.sup.12 5 .times. 10.sup.12 7 .times. 10.sup.12 64 --
EDDPO 0.1 acetonitrile 0.2 3 2 .times. 10.sup.11 4 .times.
10.sup.11 3 .times. 10.sup.11 65 citric acid 10 EDTA 0.01 methanol
0.2 2 7 .times. 10.sup.11 9 .times. 10.sup.11 8 .times. 10.sup.11
66 acetic acid 5 DEPPO 5 ethanol 0.2 1 9 .times. 10.sup.10 4
.times. 10.sup.11 6 .times. 10.sup.10 67 malonic acid 5 DEPPO 0.1
ethanol 0.2 2 4 .times. 10.sup.11 4 .times. 10.sup.10 3 .times.
10.sup.11 68 fumaric acid 5 DEPPO 0.1 ethanol 0.2 2 2 .times.
10.sup.10 3 .times. 10.sup.10 3 .times. 10.sup.10 69 malic acid 5
DEPPO 0.1 ethanol 0.2 2 4 .times. 10.sup.10 8 .times. 10.sup.10 4
.times. 10.sup.10 70 tartaric acid 5 DEPPO 0.1 ethanol 0.2 3 4
.times. 10.sup.10 9 .times. 10.sup.10 4 .times. 10.sup.10 71 citric
acid 20 DEPPO 5 ethanol 10 1 7 .times. 10.sup.10 4 .times.
10.sup.10 2 .times. 10.sup.11 72 citric acid 5 hexameta- 0.1
ethanol 0.2 2 9 .times. 10.sup.11 7 .times. 10.sup.10 4 .times.
10.sup.10 phosphoric acid 73 citric acid 5 EDTPO 0.1
isopropylalcohol 0.2 2 2 .times. 10.sup.10 9 .times. 10.sup.10 7
.times. 10.sup.10 74 citric acid 5 TTHA 0.01 isopropylalcohol 0.2 2
3 .times. 10.sup.11 3 .times. 10.sup.11 5 .times. 10.sup.11 75
citric acid 10 TETHP 0.1 ethylene glycol 5 2 5 .times. 10.sup.11 4
.times. 10.sup.10 4 .times. 10.sup.10 76 citric acid 5 NTPO 0.1
ethylene glycol 0.2 2 4 .times. 10.sup.10 6 .times. 10.sup.10 3
.times. 10.sup.11
Comparative Examples 83 to 95
[0125] The wafers contaminated with metals were treated in the
similar way as in Examples 45 to 76 except for using various
solutions described in Table 5. Thereafter, the same measurement
and evaluation as in Examples 45 to 76 were carried out for the
wafers contaminated with metals.
[0126] The results are shown in Tables 5. TABLE-US-00005 TABLE 5
conc. conc. remaining remaining remaining Comp. (% by Complexing (%
by Organic conc. Fe conc. Al conc. Cu conc. Ex. Organic acid WT)
agent WT) solvent (% by WT) pH (Fe atom/cm.sup.2) (Al
atom/cm.sup.2) (Cu atom/cm.sup.2) 83 -- -- -- 7 1 .times. 10.sup.13
9 .times. 10.sup.12 7 .times. 10.sup.12 84 -- HEDEPO 0.1 -- 3 4
.times. 10.sup.12 6 .times. 10.sup.12 7 .times. 10.sup.12 85 citric
acid 20 EDTPO 5 -- 1 1 .times. 10.sup.10 6 .times. 10.sup.10 7
.times. 10.sup.10 86 citric acid 5 TTHA 0.01 -- 2 1 .times.
10.sup.10 5 .times. 10.sup.11 5 .times. 10.sup.11 87 citric acid 5
DEPPO 1 -- 2 4 .times. 10.sup.10 9 .times. 10.sup.10 8 .times.
10.sup.11 88 citric acid 5 EDTA 0.01 -- 2 9 .times. 10.sup.10 9
.times. 10.sup.12 6 .times. 10.sup.10 89 citric acid 5 TETHP 0.1 --
2 7 .times. 10.sup.11 8 .times. 10.sup.11 8 .times. 10.sup.10 90
citric acid 5 NTPO 0.1 -- 2 4 .times. 10.sup.10 1 .times. 10.sup.11
3 .times. 10.sup.11 91 citric acid 5 hexameta- 0.1 -- 2 4 .times.
10.sup.11 7 .times. 10.sup.10 9 .times. 10.sup.10 phosphoric acid
92 citric acid 5 ammonium 1 -- 2 5 .times. 10.sup.11 1 .times.
10.sup.11 3 .times. 10.sup.11 fluoride 93 citric acid 5 ammonium
0.1 -- 2 .sup. 4 .times. 10.sup.121 2 .times. 10.sup.11 1 .times.
10.sup.11 fluoride 94 citric acid 5 ammonium 0.2 -- 2 4 .times.
10.sup.10 9 .times. 10.sup.10 9 .times. 10.sup.10 fluoride 95
citric acid 5 ammonium 0.2 -- 2 4 .times. 10.sup.10 8 .times.
10.sup.10 6 .times. 10.sup.10 fluoride
[0127] As apparent from the results of Table 4 and Table 5, it can
be understood that use of the cleaning agent of the present
invention can greatly reduce an amount of metal remaining on a
surface of wafer and the capability thereof is equivalent or better
than the cleaning agent conventionally used.
[0128] As apparent from the above, it can be understood that the
cleaning agent according to the present invention can not only well
remove a carbon defect remaining on a surface of substrate, but
also effectively remove impurities derived from various kinds of
metals (metallic impurities) at the same time.
Examples 77 to 108
[0129] The wafers contaminated with metals prepared by the above
method were subjected to a brush scrub cleaning using a brush made
of poly(vinyl alcohol), while each of the cleaning agents described
in Table 6 was sprayed on a surface of said wafers. The treatment
temperature was 25.degree. C., and cleaning time was 1 min. After
cleaning, the wafers were rinsed with ultra pure water for 10 min,
and spin-dried.
[0130] For the wafers contaminated with metals thus treated,
remaining metal concentrations (remaining Fe concentration,
remaining Al concentration, and remaining Cu concentration)
adsorbed and remaining on a surface of the wafer were measured, to
evaluate capability of removing metallic impurities.
[0131] The results are shown in Table 6 TABLE-US-00006 TABLE 6
conc. remaining remaining remaining (% by Complexing conc. conc. Fe
conc. Al conc. Cu conc. Ex. Organic acid WT) agent (% by WT)
Organic solvent (% by WT) pH (Fe atom/cm.sup.2) (Al atom/cm.sup.2)
(Cu atom/cm.sup.2) 77 citric acid 5 -- methanol 0.2 2 8 .times.
10.sup.12 1 .times. 10.sup.13 1 .times. 10.sup.13 78 acetic acid 5
-- methanol 0.2 2 7 .times. 10.sup.12 6 .times. 10.sup.12 7 .times.
10.sup.12 79 malonic acid 5 -- isopropylalcohol 5 3 5 .times.
10.sup.12 1 .times. 10.sup.13 8 .times. 10.sup.12 80 fumaric acid 5
-- 2-methoxyethanol 10 3 9 .times. 10.sup.12 1 .times. 10.sup.13 9
.times. 10.sup.12 81 malic acid 5 -- ethylene glycol 2 3 6 .times.
10.sup.12 1 .times. 10.sup.13 8 .times. 10.sup.12 82 tartaric acid
5 -- diethylene glycol 5 3 8 .times. 10.sup.12 7 .times. 10.sup.12
5 .times. 10.sup.12 monomethyl ether 83 oxalic acid 5 -- acetone
0.2 2 9 .times. 10.sup.12 5 .times. 10.sup.12 8 .times. 10.sup.12
84 oxalic acid 5 -- acetonitrile 0.2 2 7 .times. 10.sup.12 6
.times. 10.sup.12 1 .times. 10.sup.13 85 -- EDTA 0.01 methanol 0.2
5 9 .times. 10.sup.12 8 .times. 10.sup.12 1 .times. 10.sup.13 86 --
DEPPO 0.1 methanol 0.2 3 1 .times. 10.sup.12 6 .times. 10.sup.11 7
.times. 10.sup.11 87 -- EDTPO 0.1 isopropylalcohol 0.2 2 5 .times.
10.sup.11 1 .times. 10.sup.12 9 .times. 10.sup.11 88 -- CyDTA 0.01
2-methoxyethanol 0.2 5 5 .times. 10.sup.12 1 .times. 10.sup.13 6
.times. 10.sup.12 89 -- HEDPO 0.1 2-methoxyethanol 0.2 3 5 .times.
10.sup.11 1 .times. 10.sup.12 3 .times. 10.sup.11 90 -- HEDPO 0.1
ethylene glycol 0.2 3 6 .times. 10.sup.11 7 .times. 10.sup.11 6
.times. 10.sup.11 91 -- DETPPO 5 diethylene glycol 0.2 2 5 .times.
10.sup.11 1 .times. 10.sup.12 5 .times. 10.sup.11 monomethyl ether
92 -- DETPPO 0.1 diethylene glycol 0.2 3 8 .times. 10.sup.11 1
.times. 10.sup.12 8 .times. 10.sup.11 monomethyl ether 93 -- HEDPO
0.1 acetone 5 3 9 .times. 10.sup.11 6 .times. 10.sup.11 9 .times.
10.sup.11 94 -- PTDMP 0.1 acetone 0.2 3 5 .times. 10.sup.11 1
.times. 10.sup.12 5 .times. 10.sup.11 95 -- EDTA 0.1 acetonitrile 5
5 8 .times. 10.sup.12 1 .times. 10.sup.13 8 .times. 10.sup.12 96 --
EDDPO 0.1 acetonitrile 0.2 3 5 .times. 10.sup.11 7 .times.
10.sup.11 8 .times. 10.sup.11 97 citric acid 10 EDTA 0.01 methanol
0.2 2 5 .times. 10.sup.11 2 .times. 10.sup.11 1 .times. 10.sup.11
98 acetic acid 5 DEPPO 5 ethanol 0.2 2 5 .times. 10.sup.11 1
.times. 10.sup.10 1 .times. 10.sup.10 99 malonic acid 5 DEPPO 0.1
ethanol 0.2 3 5 .times. 10.sup.11 1 .times. 10.sup.10 1 .times.
10.sup.10 100 fumaric acid 5 DEPPO 0.1 ethanol 0.2 3 5 .times.
10.sup.11 1 .times. 10.sup.10 1 .times. 10.sup.10 101 malic acid 5
DEPPO 0.1 ethanol 0.2 3 5 .times. 10.sup.11 1 .times. 10.sup.10 3
.times. 10.sup.10 102 tartaric acid 5 DEPPO 0.1 ethanol 0.2 3 5
.times. 10.sup.11 1 .times. 10.sup.10 3 .times. 10.sup.10 103
citric acid 20 DEPPO 5 ethanol 10 1 4 .times. 10.sup.10 9 .times.
10.sup.10 8 .times. 10.sup.11 104 citric acid 5 hexameta- 0.1
ethanol 0.2 2 4 .times. 10.sup.13 7 .times. 10.sup.10 9 .times.
10.sup.11 phosphoric acid 105 citric acid 5 EDTPO 0.1
isopropylalcohol 0.2 2 1 .times. 10.sup.10 4 .times. 10.sup.10 2
.times. 10.sup.10 106 citric acid 5 TTHA 0.01 isopropylalcohol 0.2
2 1 .times. 10.sup.10 5 .times. 10.sup.11 3 .times. 10.sup.11 107
citric acid 5 TETHP 0.1 ethylene glycol 5 2 7 .times. 10.sup.11 8
.times. 10.sup.10 2 .times. 10.sup.10 108 citric acid 5 NTPO 0.1
ethylene glycol 0.2 2 4 .times. 10.sup.10 1 .times. 10.sup.11 3
.times. 10.sup.11
Comparative Examples 96 to 108
[0132] The wafers contaminated with metals were treated in the
similar way as in Examples 77 to 108 except for using various
solutions described in Table 7. Thereafter, the same measurement
and evaluation as in Examples 77 to 108 were carried out for the
wafers contaminated with metals.
[0133] The results are shown in Tables 7. TABLE-US-00007 TABLE 7
conc. remaining remaining remaining Comp. (% by Complexing conc.
conc. Fe conc. Al conc. Cu conc. Ex. Organic acid WT) agent (% by
WT) Organic solvent (% by WT) pH (Fe atom/cm.sup.2) (Al
atom/cm.sup.2) (Cu atom/cm.sup.2) 96 -- -- -- 7 8 .times. 10.sup.12
8 .times. 10.sup.12 1 .times. 10.sup.13 97 -- HEDEPO 0.1 -- 3 5
.times. 10.sup.12 1 .times. 10.sup.13 6 .times. 10.sup.11 98 citric
acid 20 EDTPO 5 -- 1 9 .times. 10.sup.12 3 .times. 10.sup.12 1
.times. 10.sup.13 99 citric acid 5 TTHA 0.01 -- 2 7 .times.
10.sup.12 5 .times. 10.sup.12 6 .times. 10.sup.12 100 citric acid 5
DEPPO 1 -- 2 9 .times. 10.sup.12 9 .times. 10.sup.12 7 .times.
10.sup.12 101 citric acid 5 EDTA 0.01 -- 2 1 .times. 10.sup.13 2
.times. 10.sup.12 5 .times. 10.sup.12 102 citric acid 5 TETHP 0.1
-- 2 5 .times. 10.sup.11 8 .times. 10.sup.12 6 .times. 10.sup.12
103 citric acid 5 NTPO 0.1 -- 2 6 .times. 10.sup.12 1 .times.
10.sup.12 1 .times. 10.sup.13 104 citric acid 5 hexameta- 0.1 -- 2
8 .times. 10.sup.12 7 .times. 10.sup.12 2 .times. 10.sup.13
phosphoric acid 105 citric acid 5 ammonium 1 -- 2 5 .times.
10.sup.11 1 .times. 10.sup.13 3 .times. 10.sup.12 fluoride 106
citric acid 5 ammonium 0.1 -- 2 6 .times. 10.sup.11 2 .times.
10.sup.12 1 .times. 10.sup.10 fluoride 107 citric acid 5 ammonium
0.2 -- 2 4 .times. 10.sup.10 9 .times. 10.sup.12 6 .times.
10.sup.10 fluoride 108 citric acid 5 ammonium 0.2 -- 2 3 .times.
10.sup.10 4 .times. 10.sup.12 4 .times. 10.sup.10 fluoride
[0134] As apparent from the results of Table 6 and Table 7, it can
be understood that amount of metals remaining on a surface of wafer
can be remarkably reduced when a physical cleaning was conducted
using the cleaning agent of the present invention.
Examples 109 to 140
[0135] The wafer contaminated with particles prepared by the
above-described method was dipped in 1 L each of cleaning agents
described in Table 8, at room temperature for 5 hours. Thereafter,
said wafer was taken out, rinsed with ultra pure water for 10 mins,
and spin-dried.
[0136] For the wafers contaminated with particles thus treated,
number of particles adsorbed and remaining on a surface of the
wafer were measured, to evaluate capability of removing
particles.
[0137] The results are shown in Table 8. TABLE-US-00008 TABLE 8
conc. Complexing conc. conc. number of particle Ex. Organic acid (%
by WT) agent (% by WT) Organic solvent (% by WT) pH
(particle/wafer) 109 citric acid 5 -- methanol 0.2 2 500 110 acetic
acid 5 -- methanol 0.2 2 200 111 malonic acid 5 -- isopropylalcohol
0.2 2 300 112 fumaric acid 5 -- 2-methoxyethanol 0.2 2 400 113
malic acid 5 -- ethylene glycol 0.2 2 300 114 tartaric acid 5 --
diethylene glycol 0.2 2 400 monomethyl ether 115 oxalic acid 5 --
acetone 0.2 2 500 116 oxalic acid 5 -- acetonitrile 0.2 2 300 117
-- EDTA 0.01 methanol 0.2 5 200 118 -- DEPPO 0.1 methanol 0.2 3 300
119 -- EDTPO 0.1 isopropylalcohol 0.2 3 200 120 -- CyDTA 0.01
2-methoxyethanol 0.2 5 300 121 -- HEDPO 0.1 2-methoxyethanol 5 2
300 122 -- HEDPO 0.1 ethylene glycol 5 3 400 123 -- DETPPO 5
diethylene glycol 0.2 2 200 monomethyl ether 124 -- DETPPO 0.1
diethylene glycol 0.2 3 300 monomethyl ether 125 -- HEDPO 0.1
acetone 0.2 3 200 126 -- PTDMP 0.1 acetone 1 2 100 127 -- EDTA 0.01
acetonitrile 0.2 5 400 128 -- EDDPO 0.1 acetonitrile 1 2 300 129
citric acid 20 EDTA 0.01 methanol 0.2 1 300 130 acetic acid 5 DEPPO
5 ethanol 0.2 2 300 131 malonic acid 5 DEPPO 0.1 methanol 0.2 2 400
132 fumaric acid 5 DEPPO 0.1 ethanol 0.2 2 500 133 malic acid 5
DEPPO 0.1 ethanol 0.2 2 300 134 tartaric acid 5 DEPPO 5 ethanol 0.2
2 300 135 citric acid 20 DEPPO 5 ethanol 0.2 1 500 136 citric acid
10 hexameta- 0.1 ethanol 0.2 2 500 phosphoric acid 137 citric acid
5 EDTPO 0.1 isopropylalcohol 0.2 2 300 138 citric acid 5 TTHA 0.01
isopropylalcohol 0.2 2 500 139 citric acid 5 TETHP 0.1 ethylene
glycol 0.2 2 400 140 citric acid 5 NTPO 0.1 ethylene glycol 0.2 2
300
Comparative Examples 109 to 121
[0138] The wafers contaminated with particles were treated in the
similar way as in Examples 109 to 140 except for using various
solutions described in Table 9. Thereafter, the same measurement
and evaluation as in Examples 109 to 140 were carried out for the
wafers contaminated with particles.
[0139] The results are shown in Tables 9. TABLE-US-00009 TABLE 9
Comp. conc. Complexing conc. conc. number of particle Ex. Organic
acid (% by WT) agent (% by WT) Organic solvent (% by WT) pH
(particle/wafer) 109 -- -- -- 7 6000 110 -- HEDPO 5 -- 2 200 111
citric acid 10 EDTPO 5 -- 2 500 112 citric acid 5 TTHA 0.01 -- 2
600 113 citric acid 5 DEPPO 1 -- 2 500 114 citric acid 5 EDTA 0.01
-- 2 300 115 citric acid 5 TETHP 0.1 -- 2 400 116 citric acid 5
NTPO 0.1 -- 2 600 117 citric acid 5 hexameta- 0.1 -- 2 400
phosphoric acid 118 citric acid 10 ammonium 1 -- 2 300 fluoride 119
citric acid 5 ammonium 0.1 -- 2 300 fluoride 120 citric acid 5
ammonium 0.2 -- 2 500 fluoride 121 citric acid 5 ammonium 0.2 -- 2
500 fluoride
[0140] As apparent from the results of Table 8 and Table 9, it can
be understood that use of the cleaning agent of the present
invention can remove particles on a surface of wafer and the
capability thereof is equivalent or better than the cleaning agent
conventionally used.
[0141] As apparent from the above, it can be understood that the
cleaning agent according to the present invention can not only well
remove a carbon defect remaining on a surface of substrate, but
also effectively remove fine particles (particles) present on a
surface of substrate as well as impurities derived from various
kinds of metals (metallic impurities) at the same time.
* * * * *