U.S. patent application number 09/865399 was filed with the patent office on 2001-12-13 for stripper pretreatment.
This patent application is currently assigned to Shipley Company, L.L.C. of Marlborough, Massachusetts. Invention is credited to Chu, John Cheung-Shing.
Application Number | 20010051318 09/865399 |
Document ID | / |
Family ID | 24362105 |
Filed Date | 2001-12-13 |
United States Patent
Application |
20010051318 |
Kind Code |
A1 |
Chu, John Cheung-Shing |
December 13, 2001 |
Stripper pretreatment
Abstract
Disclosed are compositions useful for the pretreatment of
polymeric material to be removed from substrates, such as
electronic devices. The compositions of the present invention are
particularly suitable for pretreating polymer residues from plasma
etch processes. Also disclosed are methods of removing such
pretreated polymeric material.
Inventors: |
Chu, John Cheung-Shing; (San
Jose, CA) |
Correspondence
Address: |
EDWARDS & ANGELL, LLP
Dike, Bronstein, Roberts & Cushman, IP Group
P.O. Box 9169
Boston
MA
02209
US
|
Assignee: |
Shipley Company, L.L.C. of
Marlborough, Massachusetts
|
Family ID: |
24362105 |
Appl. No.: |
09/865399 |
Filed: |
May 25, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09865399 |
May 25, 2001 |
|
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09590400 |
Jun 8, 2000 |
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6274296 |
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Current U.S.
Class: |
430/329 ;
29/603.07; 430/320; 430/331 |
Current CPC
Class: |
Y10T 29/49032 20150115;
G03F 7/425 20130101 |
Class at
Publication: |
430/329 ;
430/331; 430/320; 29/603.07 |
International
Class: |
G03F 007/42 |
Claims
What is claimed is:
1. A composition comprising one or more polyol compounds, one or
more glycol ethers, water, one or more surfactants and optionally
one or more additives, wherein the composition is substantially
free of amines, alkanolamines, hydroxylamines, tetraalkylammonium
hydroxides, ammonium bifluoride, ammonium-tetramethylammonium
bifluoride, and alkali metal hydroxides.
2. The composition of claim 1 wherein the polyol compound is
selected from (C.sub.2C.sub.20)alkanediols, substituted
(C.sub.2-C.sub.20)alkanediols, (C.sub.2-C.sub.20)alkanetriols or
substituted (C.sub.2C.sub.20)alkanetrio- ls.
3. The composition of claim 1 wherein the polyol is selected from
ethylene glycol, propylene glycol, diethylene glycol, dipropylene
glycol, triethylene glycol, tripropylene glycol,
2-methyl-1,3-propanediol, butanediol, pentanediol, hexanediol, or
glycerol.
4. The composition of claim 1 wherein the polyol is present in an
amount of from about 0.5 to about 20% wt based on the total weight
of the composition
5. The composition of claim 1 wherein the glycol ether is selected
from (C.sub.1-C.sub.20)alkanediol (C.sub.1-C.sub.6)alkyl ethers or
(C.sub.1-C.sub.20)alkanediol di(C.sub.1-C.sub.6)alkyl ethers.
6. The composition of claim 1 wherein the glycol ether is selected
from ethylene glycol monomethyl ether, diethylene glycol monomethyl
ether, propylene glycol monomethyl ether, propylene glycol dimethyl
ether, propylene glycol mono-n-butyl ether, dipropylene glycol
monomethyl ether, dipropylene glycol dimethyl ether, dipropylene
glycol mono-n-butyl ether or tripropylene glycol monomethyl
ether.
7. The composition of claim 1 wherein the glycol ether is present
in an amount of from about 0.5 to about 20% wt, based on the total
weight of the composition.
8. The composition of claim 1 wherein at least one surfactant is a
nonionic surfactant.
9. The composition of claim 8 wherein the nonionic surfactant is
selected from ethoxylated alkylphenols, fatty acid ethoxylates,
fatty alcohol ethoxylates, or ethylene oxide/propylene oxide
("EO/PO") condensates.
10. The composition of claim 1 wherein the optional additive is
selected from corrosion inhibitors, co-solvents or chelating
agents.
11. The composition of claim 10 wherein the corrosion inhibitor is
selected from catechol, (C.sub.1-C.sub.6)alkylcatechol,
benzotriazole, hydroxyanisole,
(C.sub.1-C.sub.10)alkylbenzotriazoles,
(C.sub.1-C.sub.10)hydroxyalkylbenzotriazoles;
2-mercaptobenimidazole, gallic acid, or gallic acid esters.
12. A method of pretreating polymeric material to be removed from a
substrate comprising the step of contacting a substrate containing
polymeric material to be removed with the composition of claim
1.
13. A method for preparing integrated circuits comprising one or
more polymeric materials to be removed comprising the steps of; a)
contacting the polymeric material with a pretreatment composition
comprising one or more one or more polyol compounds, one or more
glycol ethers, water and one or more surfactants for a period of
time sufficient to pretreat the polymeric material; b) removing the
polymeric material from contact with the pretreatment composition;
and c) then contacting the polymeric material with a polymer
stripping composition; wherein the pretreatment composition is
substantially free of amines, alkanolamines, hydroxylamines,
tetraalkylammonium hydroxides, ammonium bifluoride,
ammoniumtetramethylammonium bifluoride, and alkali metal
hydroxides.
14. The method of claim 15 wherein wherein the polyol compound is
selected from (C.sub.2-C.sub.20)alkanediols, substituted
(C.sub.2-C.sub.20)alkaned- iols, (C.sub.2-C.sub.20)alkanetriols or
substituted (C.sub.2-C.sub.20)alkanetriols.
15. The method of claim 13 wherein the polyol is selected from
ethylene glycol, propylene glycol, diethylene glycol, dipropylene
glycol, triethylene glycol, tripropylene glycol,
2-methyl-1,3-propanediol, butanediol, pentanediol, hexanediol, or
glycerol.
16. The method of claim 13 wherein the glycol ether is selected
from (C.sub.1-C.sub.20)alkanediol (C.sub.1-C.sub.6)alkyl ethers or
(C.sub.1-C.sub.20)alkanediol di(C.sub.1-C.sub.6)alkyl ethers.
17. The method of claim 13 wherein the glycol ether is selected
from ethylene glycol monomethyl ether, diethylene glycol monomethyl
ether, propylene glycol monomethyl ether, propylene glycol dimethyl
ether, propylene glycol mono-n-butyl ether, dipropylene glycol
monomethyl ether, dipropylene glycol dimethyl ether, dipropylene
glycol mono-n-butyl ether or tripropylene glycol monomethyl
ether.
18. The method of claim 13 wherein at least one surfactant is a
nonionic surfactant.
19. The method of claim 18 wherein the nonionic surfactant is
selected from ethoxylated alkylphenols, fatty acid ethoxylates,
fatty alcohol ethoxylates, or ethylene oxide/propylene oxide
("EO/PO") condensates.
20. A method for preparing magnetic thin film heads comprising the
steps of: a) contacting a magnetic thin film head precursor
containing a polymeric material to be removed with a pretreatment
composition comprising one or more polyol compounds, one or more
glycol ethers, water and one or more surfactants for a period of
time sufficient to pretreat the polymeric material; b) removing the
polymeric material from contact with the pretreatment composition;
and c) then contacting the polymeric material with a polymer
stripping composition; wherein the pretreatment composition is
substantially free of amines, alkanolamines, hydroxylamines,
tetraalkylammonium hydroxides, ammonium bifluoride,
ammonium-tetramethylammonium bifluoride, and alkali metal
hydroxides.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to the field of
removal of polymeric materials from a substrate. In particular, the
present invention relates to compositions and methods as
pretreatments for the removal of polymer material, and particularly
plasma induced polymeric material, from electronic devices.
[0002] Numerous materials containing polymers are used in the
manufacture of electronic devices, such as circuits, disk drives,
storage media devices and the like. Such polymeric materials are
found in photoresists, solder masks, antireflective coatings, and
the like. For example, modern technology utilizes positive-type
resist materials for lithographically delineating patterns onto a
substrate so that the patterns can be subsequently etched or
otherwise defined into the substrate material. The resist material
is deposited as a film and the desired pattern is defined by
exposing the resist film to energetic radiation. Thereafter the
exposed regions are subject to a dissolution by a suitable
developer liquid. After the pattern has been thus defined in the
substrate the resist material must be completely removed from the
substrate to avoid adversely affecting or hindering subsequent
operations or processing steps.
[0003] It is necessary in such a photolithographic process that the
photoresist material, following pattern delineation, be evenly and
completely removed from all unexposed areas so as to permit further
lithographic operations. Even the partial remains of a resist in an
area to be further patterned is undesirable. Also, undesired
residue between patterned features can have deleterious effects on
subsequent film depositions processes, such as metallization, or
cause undesirable surface states and charges leading to reduced
device performance.
[0004] Numerous polymer stripper compositions have been developed
to remove positive and negative photoresists. For example, U.S.
Pat. No. 5,962,197 (Chen) discloses a composition for removing
photoresists or soldermasks containing 30-80% by weight of a
propylene glycol ether, 10-60% by weight of a pyrrolidone, 0.1-5%
by weight of potassium hydroxide, 0.1-10% by weight of a
surfactant, 0-20% by weight of 1,3-butanediol, 0-10% by weight of
2-(2-aminoethoxy)ethanol, and a water content of <1%. Other
compositions are known that contain amines, such as alkanolamines,
or tetraalkylammonium hydroxides, such as tetramethylammonium
hydroxide, as the active polymer removing agent. Surfactants may
optionally be used in such compositions. See, for example, PCT
patent application WO 88/05813 (Martin et al.) which discloses a
mixture having a selected solvent as the major component and a
tetraalkylammonium hydroxide as a minor component and optionally a
surfactant.
[0005] The semiconductor industry is moving toward sub-quarter
micron geometry features. As the geometry of the features gets
smaller and pattern density increases, plasma etching, reactive ion
etching, ion milling and the like are required for the lithographic
process. During such plasma etching, reactive ion etching and ion
milling processes, the polymeric material is subjected to
conditions that make the removal of such polymeric material
difficult. During the plasma etch process a photoresist film forms
a hard to remove organometallic polymeric residue on the sidewalls
of the various features being etched. Furthermore, the photoresist
is extensively cross-linked due to the high vacuum and high
temperature conditions in the etch chamber. Known cleaning
processes do not acceptably remove such polymeric residue. For
example, acetone or N-methylpyrrolidinone is currently used at
extreme conditions, which include high temperature and extended
cycle times. Such use conditions are often above the flashpoint of
the solvent which raises certain environmental, health and safety
issues regarding operator exposure. In addition, productivity and
throughput are adversely affected by the extended process cycle
times required. Even with such extreme stripping conditions, the
devices may have to undergo wet strip followed by de-scum (O.sub.2
plasma ash) and a subsequent wet clean for a wet-dry-wet strip
process.
[0006] Known stripping compositions for post-plasma etch polymer
removal applications have numerous drawbacks including, undesirable
flammability, toxicity, volatility, odor, necessity for use at
elevated temperatures such as up to 100.degree. C., and high cost
due to handling regulated materials. A particular problem with
advanced next generation semiconductor devices is that known
stripping compositions are incompatible with a variety of thin
films in such devices, that is, such known stripping compositions
cause corrosion of the thin films, specifically copper, and low-k
dielectric material present in such advanced devices.
[0007] Methods for increasing the effectiveness of polymer removers
have been proposed. For example, U.S. Pat. No. 4,786,578 (Neisius
et al.) discloses a rinse solution used after a photoresist
stripper. This rinse solution contains a nonionic surfactant and an
organic base, such as an alkanolamine, that will form a
water-soluble salt with alkylbenzenesulfonic acids. U.S. Pat. No.
4,824,762 (Kobayashi et al.) discloses a photoresist stripper post
rinse containing a glycol ether and an aliphatic amine. In both
patents, the compositions contain amines which tend to cause
corrosion of copper present in the electronic devices. A
pretreatment has been proposed using hot (110-125.degree. C.)
solvent, see U.S. Pat. No. 4,202,703 (Zuber et al.). In this
patent, the pretreatment was followed by a stripper containing a
tetraalkylammonium hydroxide and then a post rinse with
1,1,1-trichloroethane. Such a process raises a number of
environmental concerns.
[0008] There is thus a continuing need to effectively remove
polymeric material, including post plasina etch polymeric material,
from electronic devices in ways that are environmentally
compatible, that do not damage the features and geometries of the
electronic devices, that do not cause corrosion of the substrate,
particularly thin metal films, and that do not etch dielectric
layers in the substrate.
SUMMARY OF THE INVENTION
[0009] It has been surprisingly found that polymeric material may
be easily and cleanly removed from substrates, particularly 100%
copper substrates with dielectric materials by first pretreating
the polymeric material and then contacting the polymeric material
with a stripping composition. Such polymeric material may be
removed according to the present invention without corrosion of
underlying metal layers, specifically copper, and without etching
of conventional dielectric materials, such as silicon dioxide and
low dielectric constant ("low k") materials.
[0010] In one aspect, the present invention provides a composition
for the pretreatment of polymeric material to be removed from a
substrate including one or more polyol compounds, one or more
glycol ethers, water and one or more surfactants, wherein the
composition is substantially free of amines, alkanolamines,
hydroxylamines, tetraalkylammonium hydroxides, ammonium bifluoride,
ammonium-tetramethylammonium bifluoride, and alkali metal
hydroxides.
[0011] In a second aspect, the present invention provides a method
of pretreating polymeric material to be removed from a substrate
including the step of contacting a substrate containing polymeric
material to be removed with the composition described above.
[0012] In a third aspect, the present invention provides a method
for preparing integrated circuits including one or more polymeric
materials to be removed including the steps of: a) contacting the
polymeric material with a pretreatment composition including one or
more one or more polyol compounds, one or more glycol ethers, water
and one or more surfactants for a period of time sufficient to
pretreat the polymeric material; b) removing the polymeric material
from contact with the pretreatment composition; and c) then
contacting the polymeric material with a polymer stripping
composition; wherein the pretreatment composition is substantially
free of amines, alkanolamines, hydroxylamines, tetraalkylammonium
hydroxides, ammonium bifluoride, ammonium-tetramethylammonium
bifluoride, and alkali metal hydroxides.
[0013] In a fourth aspect, the present invention provides a method
for preparing magnetic thin film heads including the steps of: a)
contacting a magnetic thin film head precursor containing a
polymeric material to be removed with a pretreatment composition
including one or more polyol compounds, one or more glycol ethers,
water and one or more surfactants for a period of time sufficient
to pretreat the polymeric material; b) removing the polymeric
material from contact with the pretreatment composition; and c)
then contacting the polymeric material with a polymer stripping
composition, wherein the pretreatment composition is substantially
free of amines, alkanolamines, hydroxylamines, tetraalkylammonium
hydroxides, ammonium bifluoride, ammonium-tetramethylammonium
bifluoride, and alkali metal hydroxides.
DETAILED DESCRIPTION OF THE INVENTION
[0014] As used throughout this specification, the following
abbreviations shall have the following meanings unless the context
clearly indicates otherwise: .degree. C.=degrees Centigrade;
%wt=percent by weight; mL=milliliter; min=minute; DPM=dipropylene
glycol monomethyl ether; DPNB=dipropylene glycol mono-n-butyl
ether; and MP-diol=2-methyl-1,3-prop- anediol. All percentages are
by weight. All numerical ranges are inclusive and combinable.
[0015] The terms "stripping" and "removing" are used
interchangeably throughout this specification. Likewise, the terms
"stripper" and "remover" are used interchangeably. "Alkyl" refers
to linear, branched and cyclic alkyl. The term "substituted alkyl"
refers to an alkyl group having one or more of its hydrogens
replaced with another substituent group, such as halogen, cyano,
nitro, (C.sub.1-C.sub.6)alkoxy, mercapto,
(C.sub.1-C.sub.6)alkylthio, and the like. As used throughout this
specification, the term "aprotic" refers to compounds that do not
accept or yield a proton. The term "glycol" refers to dihydric
alcohols. Thus, the term "glycol ether" refers to ethers of
dihydric alcohols.
[0016] Polymeric material on a substrate, including post plasma
etch polymeric material, may be effectively removed by first
treating or pretreating the polymeric material to be removed with
the pretreatment composition according to the present invention.
The polymeric material is then removed from contact with the
pretreatment composition and then contacted with a polymer
stripping composition. It is preferred that the substrate is not
rinsed prior to the pretreatment step. It is further preferred that
the polymeric material is not rinsed between the pretreating step
and the polymer stripping step. Thus, the substrate containing the
polymeric material is removed from contact with the pretreatment
composition and directly contacted with a polymer stripping
composition. Typically, the substrate is rinsed after the polymer
stripping step.
[0017] The compositions useful for pretreating polymeric material
according to the present invention include one or more polyol
compounds, one or more glycol ethers, water and one or more
surfactants. Such pretreatment compositions are typically
substantially free of polymer removing components, such as amines,
alkanolamines, hydroxylamines, tetraalkylammonium hydroxides,
ammonium bifluoride, ammonium-tetramethylammonium bifluoride,
alkali metal hydroxides and the like. It is preferred that the
pretreatment compositions of the present invention are free of
amines, alkanolamines, hydroxylamines, tetraalkylammonium
hydroxides, ammonium bifluoride, ammonium-tetramethylammonium
bifluoride and lakali metal hydroxides.
[0018] The polyol compounds useful in the present invention are any
which are miscible with water and do not destabilize the
composition. By the term "polyol compound" is meant a compound
having two or more hydroxyl groups. Suitable polyol compounds
include aliphatic polyol compounds such as
(C.sub.2-C.sub.20)alkanediols, substituted
(C.sub.2-C.sub.20)alkanedio- ls, (C.sub.2C.sub.20)alkanetriols,
substituted (C.sub.2-C.sub.20)alkanetri- ols, and the like.
Suitable aliphatic polyol compounds include, but are not limited
to, ethylene glycol, propylene glycol, diethylene glycol,
dipropylene glycol, triethylene glycol, tripropylene glycol,
2-methyl-1,3-propanediol, butanediol, pentanediol, hexanediol,
glycerol and the like. It is preferred that the aliphatic polyol
compound is ethylene glycol, propylene glycol,
2-methyl-propanediol, butanediol or pentanediol. Such polyol
compounds are generally commercially available, such as from
Aldrich (Milwaukee, Wis.), and may be used without further
purification. The polyol compounds are typically used in the
present invention in an amount in the range of from about 0.5 to
about 20%wt based on the total weight of the composition,
preferably from about 2 to about 10% wt, and more preferably from
about 5 to about 6% wt.
[0019] The glycol ethers useful in the present invention are any
which are water miscible, compatible with the polyol compound and
do not destabilize the composition such as glycol
mono(C.sub.1-C.sub.6)alkyl ethers and glycol
di(C.sub.1-C.sub.6)alkyl ethers, such as but not limited to
(C.sub.1-C.sub.20)alkanediol (C.sub.1-C.sub.6)alkyl ethers and
(C.sub.1-C.sub.20)alkanediol di(C.sub.1-C.sub.6)alkyl ethers.
Suitable glycol ethers include, but are not limited to, ethylene
glycol monomethyl ether, diethylene glycol monomethyl ether,
propylene glycol monomethyl ether, propylene glycol dimethyl ether,
propylene glycol mono-n-butyl ether, dipropylene glycol monomethyl
ether, dipropylene glycol dimethyl ether, dipropylene glycol
mono-n-butyl ether, tripropylene glycol monomethyl ether, and the
like. It is preferred that the glycol ether is dipropylene glycol
monomethyl ether, tripropylene glycol monomethyl ether, propylene
glycol mono-n-butyl ether or dipropylene glycol mono-n-butyl ether.
Such glycol ethers are generally commercially available and may be
used without further purification. Typically, the glycol ethers are
present in the compositions of the invention in an amount in the
range of from about 0.5 to about 20% wt based on the total weight
of the composition, and preferably from about 5 to about 10%
wt.
[0020] Nonionic, anionic, cationic and amphoteric surfactants may
be used in the compositions of the present invention. Nonionic
surfactants are preferred. Such surfactants are generally
commercially available. Useful nonionic surfactants include, but
are not limited to, ethoxylated alkylphenols, fatty acid
ethoxylates, fatty alcohol ethoxylates, ethylene oxide/propylene
oxide ("EO/PO") condensates, and the like. Suitable ethoxylated
alkylphenols include ethoxylation products of
(C.sub.6-C.sub.14)alikylphenols, that is alkylphenols having 6 to
14 carbon atoms in the alkyl chain, and a degree of ethoxylation of
2 to 20. Fatty acids or fatty alcohol ethoxylates with saturated or
unsaturated hydrocarbon chains having 8 to 24 carbon atoms and a
degree of ethoxylation of 2 to 20 are also suitable. Particularly
suitable EO/PO condensates are those having about 10 to about 20 EO
or PO units.
[0021] The surfactants are typically present in an amount of from
about 0.1 to about 10% wt, preferably from about 0.5 to about 2%
wt, and more preferably from about 1 to about 1.5% wt, based on the
total weight of the composition.
[0022] Typically, deionized water is used in the present invention.
Water is present in an amount sufficient to make up 100% wt, based
on the total weight of the composition. Typically, the amount of
water is from about 50 to about 98.9% wt based on the total weight
of the composition, and preferably from about 75 to about 95%
wt.
[0023] The pretreatment compositions of the present invention may
optionally include one or more additives. Suitable additives
include, but are not limited to, corrosion inhibitors, wetting
agents, co-solvents, chelating agents and the like.
[0024] Any corrosion inhibitor which reduces the corrosion of metal
film layers is suitable for use in the present invention. Suitable
corrosion inhibitors include, but are not limited to, catechol;
(C.sub.1-C.sub.6)alkylcatechol such as methylcatechol,
ethylcatechol and tert-butylcatechol; benzotriazole;
hydroxyanisole; (C.sub.1-C.sub.10)alkylbenzotriazoles;
(C.sub.1-C.sub.10)hydroxyalkylbenz- otriazoles;
2-mercaptobenimidazole; gallic acid; gallic acid esters such as
methyl gallate and propyl gallate; and the like. It is preferred
that the corrosion inhibitor is catechol,
(C.sub.1-C.sub.6)alkylcatechol, benzotriazole or
(C.sub.1-C.sub.10)alkylbenzotriazoles, 2-mercaptobenimidazole, and
more preferably benzotriazole and tert-butylcatechol. Such
corrosion inhibitors are generally commercially available from a
variety of sources, such as Aldrich (Milwaukee, Wisconsin) and may
be used without further purification.
[0025] When such corrosion inhibitors are used in the compositions
of the present invention, they are typically present in an amount
in the range of from about 0.01 to about 10% wt, based on the total
weight of the composition. It is preferred that the amount of
corrosion inhibitor is from about 0.2 to about 5% wt, more
preferably about 0.5 to about 3% wt, and most preferably from about
1.5 to about 2.5% wt. It is preferred that a corrosion inhibitor is
used.
[0026] Suitable cosolvents useful in the compositions are any which
are water miscible and do not destabilize the present compositions.
Such suitable cosolvents include, but are not limited to, polar
aprotic solvents such as dimethyl sulfoxide, tetramethylene sulfone
(or sulfolane), and dimethyl sufur dioxide; aminoalcohols such as
aminoethylaminoethanol; N-(C.sub.1-C.sub.10)alkylpyrrolidones such
as N-methylpyrrolidone ("NMP"), N-ethylpyrrolidone,
Nhydroxyethylpyrrolidone and N-cyclohexylpyrrolidone; amides such
as dimethylacetamide ("DMAC") and the like. It is preferred that
the cosolvent is selected from
N-(C.sub.1-C.sub.10)alkylpyrrolidones and amides, more preferably
N-methylpyrrolidone, N-ethylpyrrolidone, Nhydroxyethylpyrrolidone,
N-cyclohexylpyrrolidone and dimethylacetamide. It is further
preferred that the compositions of the present invention are free
of amine cosolvent, such as aminoalcohols. When such cosolvents are
used they are typically present in an amount in the range of about
0.1 to about 20% wt, based on the total weight of the composition,
preferably about 1 to about 10% wt, and more preferably from about
1 to about 5% wt.
[0027] The compositions of the present invention may be prepared by
combining the one or more polyol compounds, one or more glycol
ethers, water, one or more surfactants and optionally one or more
additives in any order.
[0028] The compositions of the present invention are suitable for
pretreating polymeric material to be removed from a substrate. The
removal of any polymeric material, such as, but not limited to,
photoresists, soldermasks, antireflective coatings, and the like,
including such polymeric material that has been subjected to harsh
process conditions such as plasma etching, auto-plasma ashing, ion
implantation or ion milling processes, can be effectively enhanced
by first contacting it with the pretreatment compositions of the
present invention and then contacting it with known polymer
stripping compositions. Any polymeric material subjected to the
harsh treatment processes described above is referred to as
"post-plasma etch polymeric residue" throughout this specification.
The compositions and methods of the present invention are
particularly useful in aiding removal of the organometallic
polymeric residue present after a dry plasma etching, reactive ion
etching and ion milling of materials, such as photoresists,
conducting metal layers and insulating dielectric layers.
[0029] Polymeric residue on a substrate may be removed by first
contacting the substrate with a composition of the present
invention for a period of time sufficient to pretreat the polymeric
material. The substrate may be contacted with the compositions of
the present invention by any known means, such as immersion of the
substrate in a bath, such as a wet chemical bench, containing a
composition of the present invention such bath being at room
temperature or heated, or by spraying a composition of the present
invention at a desired temperature on the surface of the substrate.
Typically, the polymeric material is contacted with the
pretreatment compositions of the present invention for up to 30
minutes, preferably up to 20 minutes, and more preferably up to 15
minutes. Typically, polymeric material is pretreated with the
compositions of the present invention from about 5 to about 15
minutes.
[0030] The pretreatment compositions of the present invention may
be effectively used at a wide range of temperatures, such as but
not limited to, up to about 60.degree. C., preferably from about
20.degree. C. to about 50.degree. C., more preferably from about
23.degree. C. to about 45.degree. C., and most preferably from
about 25.degree. C. to about 35.degree. C. An advantage of the
pretreatment compositions is that they may be effectively used at
ambient temperature.
[0031] Following contact with the compositions of the present
invention, the substrate is then contacted with known polymer
stripping compositions. The substrate may be contacted with the
polymer stripping compositions by any known manner, such as
immersion of the substrate in a bath, such as a wet chemical bench,
containing the polymer stripping composition or by spraying a
polymer stripping composition on the surface of the substrate. Any
polymer stripping compositions may be advantageously used with the
pretreatment compositions of the present invention. It is preferred
that the polymer stripping compositions include one or more of one
or more polyol compounds, one or more glycol ethers and water. The
polymer stripping compositions typically contain one or more
polymer removing components, such as but not limited to amines,
alkanolamines, hydroxylamines, tetraalkylammonium hydroxides,
ammonium bifluoride, ammonium-tetramethylammonium bifluoride, and
the like. It is further preferred that the polymer removing agent
is one or more of hydroxylamines, tetraalkylammonium hydroxides,
ammonium bifluoride, and ammonium-tetramethylammonium bifluoride.
Such polymer stripping compositions are generally well known and
commercially available. Suitable polymer stripping compositions
include those sold under the tradenames ACT-935 (available from
Ashland), EKC-265 (available from EKC Technology, Hayward, Calif.),
PRX-407 and PRX-120 (both available from Shipley
Company.backslash.Silicon Valley Chemlabs, Sunnyvale, Calif.).
[0032] No special procedures are necessary for using the polymer
stripping compositions following pretreatment of polymeric material
with the compositions of the present invention. The polymer
stripping compositions are typically used in the manner recommended
by the manufacturer. Such polymer stripping compositions may be
used at ambient temperature or may be heated.
[0033] It is preferred that the substrate is not rinsed until after
the polymeric material has been subjected to the polymer stripping
compositions. Following contact with the polymer stripping
compositions, the substrate is typically rinsed such as with
deionized water, and then dried such as by spin drying.
[0034] An advantage of the pretreatment of the present invention is
that polymeric material may be effectively removed in less time as
compared to the time required to remove such polymeric material
without pretreatment. Thus, the time required for contact with
polymer stripping compositions is reduced. By reducing the time a
substrate is in contact with the harsh components of a polymer
stripping composition, adverse effects on the substrate, such as
corrosion and lifting of layers, are also reduced.
[0035] A further advantage of the compositions of the present
invention is that they may be effectively used to pretreat
polymeric material on substrates including one or more dielectric
layers. Such pretreatment allows faster removal of the polymeric
material when contacted with a polymer stripping composition. By
increasing the rate of polymer removal, the substrate is exposed to
the stripping composition for a shorter period of time and thus
etching of the dielectric material is substantially reduced.
[0036] A still further advantage of the compositions of the present
invention is that post-plasma etch polymeric material may be
removed from a substrate such that etching of thermal oxide layers
underneath metal lines is greatly reduced or eliminated.
[0037] The compositions of the present invention are particularly
useful in aiding removal of post plasma etch residues when
conventional strippers are not capable of removing such residues.
Furthermore the present pretreatment compositions are substantially
non-corrosive to substrates containing metals, particularly copper
and aluminum. It is preferred that the compositions of the present
invention are non-corrosive to metals, particularly copper and
aluminum.
[0038] Thus, the compositions of the present invention are useful
in pretreating any polymeric material that needs to be removed
during the manufacture of electronic devices, such as, but not
limited to, flat panel display TFT/LCD manufacture,
magneto-resistive and giant magnetoresistive thin film head
manufacture, or read-write device manufacture. The compositions of
the present invention are substantially inert, and preferably
completely inert, to the metal films used in magneto-resistive and
giant magneto-resistive thin film head manufacture such as, but not
limited to, aluminum oxide ("Al.sub.2O.sub.3"), gold ("Au"), cobalt
("Co"), copper ("Cu"), iron ("Fe"), iridium ("Ir"), manganese
("Mn"), molybdenum ("Mo"), nickel ("Ni"), platinum ("Pt"),
ruthenium ("Ru"), and zirconium ("Zr"), as well as other metals
used in the manufacture of semiconductors and electronic materials,
such as, but not limited to, copper, aluminum, nickel-iron,
tungsten, titanium, titanium-nitride, tantalum, tantalum
nitride.
[0039] The following examples are intended to illustrate further
various aspects of the present invention, but are not intended to
limit the scope of the invention in any aspect.
EXAMPLE 1
[0040] A pre-treatment solution was prepared by combining 5%
MP-diol, 1% Japanese soap (a nonionic surfactant), 5% DPM with the
balance being de-ionized ("DI") water.
EXAMPLE 2
[0041] A wafer containing sub-micron dual damascene vias to a
copper metal layer and post plasma etched polymeric residue was
examined by SEM which showed heavy polymer on the via bottoms as
well as some sidewall polymer. The wafer was contacted with the
solution of Example 1 (pretreated) for 1 minute at 23.degree. C.,
removed from contact with the solution and placed in a polymer
stripper (remover) bath containing 13% dimethylacetamide, 27% DPM,
28% DI water, and 28% MP-diol as active ingredients at 23.degree.
C. for 10 minutes. The wafer was then removed from the stripping
bath, rinsed for 5 minutes with the solution from Example 1 for 5
minutes, rinsed with DI water for 2 minutes and then dried. SEM
analysis showed the wafer to be clean with no polymer in the bottom
of the vias and no sidewall polymer remaining.
EXAMPLE 3 (Comparative)
[0042] The procedure of Example 2 was repeated except that the
wafer was first contacted with the polymer remover bath for 30
minutes at 23.degree. C. The wafer was removed from the bath and
placed in a bath containing the solution from Example 1 for 15
minutes. After removal from the bath, the wafer was then rinsed
with DI water for 5 minutes and dried. SEM analysis showed the
wafer to be mostly clean with polymer still remaining in the
bottoms of the vias.
EXAMPLE 4
[0043] A wafer containing sub-micron vias to an aluminum metal
layer and post plasma etched polymeric residue was examined by SEM
which showed heavy polymer on the via sidewalls. The wafer was
contacted with the solution of Example 1 (pretreated) for 1 minute
at 23.degree. C., removed from contact with the solution and placed
in the polymer stripper (remover) bath of Example 2 at 23.degree.
C. for 10 minutes. The wafer was then removed from the stripping
bath, rinsed for 5 minutes with the solution from Example 1 for 5
minutes, rinsed with DI water for 5 minutes and then dried. SEM
analysis showed the wafer to be clean with no sidewall polymer
remaining.
EXAMPLE 5
[0044] The procedure of Example 4 was repeated except that the
wafer was not subjected to a pretreatment step. After contact with
the polymer stripping bath, the wafer was then rinsed with DI water
for 5 minutes and dried. SEM analysis showed some sidewall polymer
remaining.
EXAMPLE 6
[0045] A wafer containing post plasma etch sidewall polymer residue
was contacted with the solution of Example 1 for 30 minutes at
23.degree. C. After removing the wafer from contact with the
solution, the wafer was rinsed with DI water for 5 minutes and
dried. SEM analysis of the wafer showed that the solution of
Example 1 by itself was ineffective in removing post plasma etch
sidewall polymer.
[0046] The above examples clearly show that the solutions of the
present invention are effective in pretreating substrates
containing polymeric residue to be removed. Such pretreatment
results in shorter contact times of the substrates with the polymer
stripping baths as well as more complete removal of polmeric
material, particularly post plasma etch polymeric material.
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