U.S. patent application number 09/785771 was filed with the patent office on 2002-03-28 for stripping composition.
This patent application is currently assigned to Shipley Company, L.L.C.. Invention is credited to Sahbari, Javad J..
Application Number | 20020037819 09/785771 |
Document ID | / |
Family ID | 27091588 |
Filed Date | 2002-03-28 |
United States Patent
Application |
20020037819 |
Kind Code |
A1 |
Sahbari, Javad J. |
March 28, 2002 |
Stripping composition
Abstract
Disclosed are compositions and methods useful for the removal of
polymeric material from substrates, such as electronic devices. The
compositions and methods disclosed are particularly suitable for
removing polymer residues from advanced integrated circuit devices
with reduced corrosion of metal surfaces.
Inventors: |
Sahbari, Javad J.;
(Sunnyvale, CA) |
Correspondence
Address: |
S. Matthew Cairns
EDWARDS & ANGELL, LLP
Dike, Bronstein, Roberts & Cushman, IP Group
130 Water Street
Boston
MA
02109
US
|
Assignee: |
Shipley Company, L.L.C.
Marlborough
MA
|
Family ID: |
27091588 |
Appl. No.: |
09/785771 |
Filed: |
February 16, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09785771 |
Feb 16, 2001 |
|
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09632282 |
Aug 3, 2000 |
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Current U.S.
Class: |
510/175 ;
257/E21.228; 257/E21.252; 257/E21.255; 257/E21.256; 510/176;
510/178 |
Current CPC
Class: |
H01L 21/31133 20130101;
G11B 5/3116 20130101; G03F 7/425 20130101; G11B 5/3903 20130101;
H01L 21/02052 20130101; G11B 5/3163 20130101; H01L 21/31138
20130101; H01L 21/02071 20130101; H01L 21/31116 20130101 |
Class at
Publication: |
510/175 ;
510/176; 510/178 |
International
Class: |
C11D 001/00 |
Claims
What is claimed is:
1. A composition for the removal of polymeric material from a
substrate comprising one or more polyhydric alcohols, water, one or
more water-miscible amines, and one or more polar solvents.
2. The composition of claim 1 wherein the one or more polyhydric
alcohols comprise (C.sub.2-C.sub.20)alkanediols,
(C.sub.2-C.sub.20)alkanetriols, substituted
(C.sub.2-C.sub.20)alkanediols or substituted
(C.sub.2-C.sub.20)alkanetriols.
3. The composition of claim 1 wherein the one or more polyhydric
alcohols are selected from the group consisting of ethylene glycol,
diethylene glycol, triethylene glycol, polyethylene glycol,
propylene glycol, dipropylene glycol, tripropylene glycol,
polypropylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol,
butanediol, pentanediol, hexanediol and glycerol.
4. The composition of claim 1 wherein the one or more polyhydric
alcohols are present in an amount of from about 5 to about 65% wt,
based on the total weight of the composition.
5. The composition of claim 1 wherein the water is present in an
amount of from about 5 to about 55% wt, based on the total weight
of the composition.
6. The composition of claim 1 wherein the one or more water
miscible amines is selected from the group consisting of
ethylenediamine, diethylenetriamine, triethylenetetraamine,
propylenediamine, aminoethylaminoethanol, ethanolamine,
diethanolamine, triethanolamine, monoisopropanolamine,
diisopropanolamine and 3-amino-1-propanol.
7. The composition of claim 1 wherein the amount of the one or more
water-miscible amines is from about 5 to about 65% wt, based on the
total weight of the composition.
8. The composition of claim 1 wherein the one or more polar
solvents are selected from the group consisting of polar aprotic
solvents, dimethylformamide, dimethylacetamide,
.gamma.-butyrolactone and glycol ethers.
9. The composition of claim 8 wherein the one or more polar
solvents are selected from the group consisting of dimethyl
sulfoxide, sulfolane, 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 and
tripropylene glycol monomethyl ether.
10. The composition of claim 1 wherein the amount of one or more
polar solvents is from about 5 to about 50% wt, based on the total
weight of the composition.
11. The composition of claim 1 further comprising one or more of
corrosion inhibitors or wetting agents.
12. The composition of claim 1 wherein the composition is free of
hydroxylamine, metal-ions and tetraalkylammonium hydroxide.
13. The composition of claim 1 wherein the composition is free of
ethylenediaminetetraacetic acid, alkylpyrrolidones, alkali metal
hydroxide, fluoride ion and amino acids.
14. A method of removing polymeric material from a substrate
including the step of contacting a substrate containing polymeric
material to be removed with the composition of claim 1.
15. A method for manufacturing an electronic device comprising a
substrate containing one or more metals and one or more polymeric
materials, comprising the step of contacting the substrate
containing polymeric material to be removed with a composition
comprising one or more polyhydric alcohols, water, one or more
water-miscible amines, and one or more polar solvents.
16. A composition comprising from about 5 to about 65% wt of a
polyhydric alcohol selected from 1,3-propanediol,
2-methyl-1,3-propanediol, butanediol or glycerol; from about 5 to
about 40% wt water; from about 5 to about 65% wt of one or more
water-miscible amines selected from the group consisting of
ethylenediamine, diethylenetriamine, triethylenetetraamine,
propylenediamine, aminoethylaminoethanol, ethanolamine,
diethanolamine, triethanolamine, monoisopropanolamine,
diisopropanolamine and 3-amino-1-propanol; from about 5 to about
50% wt of one or more polar aprotic solvents selected from the
group consisting of dimethyl sulfoxide, sulfolane, 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, and dipropylene glycol
mono-n-butyl ether; and from about 0.2 to about 5% wt of a
corrosion inhibitor selected from catechol,
(C.sub.1-C.sub.6)alkylcatechol, benzotriazole or
(C.sub.1-C.sub.10)alkylb- enzotriazoles.
17. The composition of claim 16 wherein the composition is free of
ethylenediaminetetraacetic acid, alkylpyrrolidones, alkali metal
hydroxide, fluoride ion and amino acids.
18. The composition of claim 16 wherein the composition is free of
hydroxylamine, metal-ions and tetraalkylammonium hydroxide.
19. The composition of claim 16 wherein the composition is free of
a chelating reagent comprising a mono- or poly-valent acid type
ligand covalently bonded to a polymeric or oligomeric backbone.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to the field of removal of
polymeric materials from a substrate. In particular, the present
invention relates to compositions and methods for the removal of
residues left behind after plasma etch and ash process of silicon
wafers used in manufacturing 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. During manufacture of such electronic devices, the
polymeric material is subjected to special processes and treatment
conditions such as halogen or halide plasma etch, auto-plasma ash
processing, reactive ion etching and ion milling that cause
extensive cross-linking of the photoresist polymer and make the
removal of such cross-linked polymeric material extremely
difficult.
[0003] 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.
[0004] 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 resist
residues between patterned lines can have deleterious effects on
subsequent processes, such as metallization, or cause undesirable
surface states and charges.
[0005] Plasma etching, reactive ion etching and ion milling are
required as the geometry of features get smaller and pattern
density increases. During the plasma etch process, a photoresist
film forms a hard to remove organometallic polymeric residue on the
side walls 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-methylpyrrolidone is used at extreme
conditions, which include high temperature and extended cycle
times. Such use conditions are often above the flash point of the
solvent which has 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 typically need manual "swabbing", or brushing, to remove
tenacious "rabbit ear"-type polymeric residue from the fine
features.
[0006] In recent years, the semiconductor manufacturing industry
has moved to dry plasma etching processes of metal and oxide layers
in order to achieve the desired features with sub-half micron
geometry. As a result, the need for photoresist and polymer
removers that work effectively without damaging the integrity of
fine feature microcircuit lines has drastically increased. Known
photoresist removal or stripping formulations that typically
contain strong alkaline solutions, organic polar solvents or strong
acids and oxidizing agents are no longer applicable for those
cross-linked polymers. Typical organic polar solvents used in
conventional stripping formulations include pyrrolidones such as
N-methylpyrrolidone, N-ethylpyrrolidone, N-hydroxyethylpyrrolidon-
e and N-cyclohexylpyrrolidone; amides including dimethylacetamide
or dimethylformamide; phenols and derivatives thereof. Such
solvents have been used in combination with amines or other
alkaline components that are effective in photoresist stripping.
These compositions are not effective in post plasma polymer removal
applications.
[0007] Recently, aqueous mixtures of hydroxylamine and
alkanolamines along with different chelating agents have been used.
For example, U.S. Pat. No. 5,334,332 (Lee) discloses compositions
for removing etching residue containing 5 to 50% hydroxylamine, 10
to 80% of at least one alkanolamine and water. U.S. Pat. No.
4,401,747 (Ward et al.) discloses a stripping composition
containing 30 to 90% 2-pyrrolidone and 10 to 70% dialkyl sulfone.
Also, U.S. Pat. No. 5,795,702 (Tanabe et al.) discloses a stripping
composition that contains 2 to 30% of hydroxylamine, 2 to 20% of an
amine, 35 to 80% of a water soluble organic solvent in water with 2
to 20% of a corrosion inhibitor.
[0008] The above described compositions may be effective on typical
Al/Si wafers that contain titanium nitride ("TiN") as cap layers
and barrier layers, however, they are not applicable to 100% copper
devices, or devices with high percentage of copper and low
dielectric constant ("low-k") dielectric materials. These
compositions are also corrosive to other corrosion sensitive
alloys, such as tungsten, gallium or gallium arsenide, that are
mainly used in modem chip manufacturing technology. Soft metals,
such as copper and tungsten, are easily corroded by any
hydroxylamine containing materials. Further, the strong tendency of
copper for complex formation with hydroxylamine makes using such
products undesirable for 100% copper or alloys having high copper
content.
[0009] In addition, known stripping compositions containing
hydroxylamine have numerous other drawbacks including, undesirable
flammability, explosion hazard, toxicity, volatility, odor,
instability at elevated process temperatures such as up to
80.degree. to 90.degree. C., and high cost due to handling such
regulated materials. A particular problem with advanced devices,
such as magnetic thin film heads for disk drives and storage media
devices, is that known stripping compositions are incompatible with
a variety of thin films in such devices, that is, conventional
stripping compositions cause corrosion of the thin metal layers,
particularly copper, and low-k dielectric material present in such
advanced devices.
[0010] Furthermore, industrial grade hydroxylamine free base has
high ionic contamination that cannot be used for electronic
applications. Further purification is therefore necessary to
convert the technical grade material to an electronic grade
product. Purification of hydroxylamine free base via distillation
processes has recently caused several fatal explosions, making
handling of such high purity material extremely dangerous.
[0011] U.S. Pat. No. 5,988,186 (Ward et al.) discloses stripping
compositions having at least about 10% by weight water, a water
soluble polar solvent, an organic amine and gallic acid or a gallic
acid ester. This patent does not disclose a combination of a
polyhydric alcohol and a polar organic solvent.
[0012] U.S. Pat. No. 5,561,105 (Honda) discloses a photoresist
stripping composition including an organic polar solvent having a
dipole moment of more than 3.5; an amine compound selected from
compounds having a certain formula, an a chelating reagent
comprising a mono- or poly-valent acid ligand covalently bonded to
a polymeric or oligomeric backbone. This patent does not disclose
polyhydric alcohols, nor compositions free of an acid-type
ligand.
[0013] There is thus a continuing need for strippers that
effectively remove polymeric material, are more environmentally
friendly, are less dangerous to manufacture and do not cause
corrosion of the substrate, particularly thin metal films and the
dielectric layers in the substrate.
SUMMARY OF THE INVENTION
[0014] It has been surprisingly found that polymeric material may
be easily and cleanly removed from substrates, particularly 100%
copper substrates and thin film heads for disk drives and storage
media devices. Such polymeric material may be removed according to
the present invention without corrosion of underlying metal layers,
specifically copper, copper alloys, tungsten and gallium.
[0015] In one aspect, the present invention provides a composition
for the removal of polymeric material from a substrate including
one or more polyhydric alcohols, water, one or more water-miscible
amines, and one or more polar solvents.
[0016] In a second aspect, the present invention provides a method
of removing polymeric material from a substrate including the step
of contacting a substrate containing polymeric material to be
removed with the composition described above.
[0017] In a third aspect, the present invention provides a method
for manufacturing an electronic device including a substrate
including one or more metals and one or more polymeric materials,
including the steps of contacting the substrate containing
polymeric material to be removed with a composition including one
or more polyhydric alcohols, water, one or more water-miscible
amines, and one or more polar solvents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a scanning electron micrograph ("SEM") of a wafer
having vias containing sidewall polymer.
[0019] FIG. 2 is a SEM of the wafer shown in FIG. 1 after removal
of the sidewall polymer using a composition of the invention.
[0020] FIG. 3 is a SEM of the wafer shown in FIG. 1 after treatment
with a conventional hydroxylamine-containing sidewall polymer
remover.
DETAILED DESCRIPTION OF THE INVENTION
[0021] As used throughout this specification, the following
abbreviations shall have the following meanings unless the context
clearly indicates otherwise: g=gram; .degree. C.=degrees
Centigrade; ppm=parts per million; .ANG. =angstrom; % wt=percent by
weight; min=minute; cm =centimeter; ml=milliliter;
MP-diol=2-methyl-1,3-propanediol; DPM=dipropylene glycol monomethyl
ether; AEEA=aminoethylaminoethanol; DMSO=dimethyl sulfoxide;
TBC=tert-butylcatechol; BTA=benzotriazole;
MIPA=monoisopropanolamine; PDO=1,3-propanediol;
AMP=3-amino-1-propanol; and EDA=ethylenediamine. All percentages
are by weight. All numerical ranges are inclusive and combinable in
any order, except where it is obvious that such numerical ranges
are constrained to add up to 100%.
[0022] The terms "stripping" and "removing" are used
interchangeably throughout this specification. Likewise, the terms
"stripper" and "remover" are used interchangeably. "Stripping"
refers to the removal of bulk polymeric material, such as
photoresists and antireflective coatings, from a substrate and to
the removal of polymeric residue after etching. The term "stripper"
does not include developers which remove unpolymerized photoresist
and leave an exact copy of the pattern on the mask or reticle.
"Alkyl" refers to linear, branched and cyclic alkyl. As used
throughout this specification, the term "aprotic" refers to
compounds that do not accept or yield a proton.
[0023] The compositions of the present invention include one or
more polyhydric alcohols, water, one or more water-miscible amines,
and optionally one or more polar solvents. "Polyhydric alcohol"
refers to any alcohol having two or more hydroxy groups, such as
(C.sub.2-C.sub.20)alkanediols, (C.sub.2-C.sub.20)alkanetriols,
substituted (C.sub.2-C.sub.20)alkanediols, substituted
(C.sub.2-C.sub.20)alkanetriols, and the like. Suitable polyhydric
alcohols include, but are not limited to, ethylene glycol,
diethylene glycol, triethylene glycol, polyethylene glycol,
propylene glycol, dipropylene glycol, tripropylene glycol,
polypropylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol,
butanediol, pentanediol, hexanediol, glycerol, and the like. It is
preferred that the polyhydric alcohol is 1,3-propanediol,
2-methyl-1,3-propanediol, butanediol or glycerol, and more
preferably 1,3-propanediol and 2-methyl-1,3-propanedio- l.
[0024] The polyhydric alcohols of the present invention are
typically used in an amount of from about 5 to about 65% wt, based
on the total weight of the composition. It is preferred that the
polyhydric alcohols are present from about 20 to about 60% wt, and
more preferably from about 25 to about 50% wt. Such polyhydric
alcohols are generally commercially available and may be used
without further purification.
[0025] Any grade of water may be used in the present invention,
such as deionized or distilled. It is preferred that deionized
("DI") water is used. An advantage of the present invention is that
large amounts of water can be used, such as up to about 75% wt. The
amount of water is preferably from about 5 to about 55% wt, based
on the total weight of the composition. More preferred amounts of
water are from about 10 to about 40% wt, and still more preferably
from about 10 to about 35% wt. A particularly suitable amount of
water is from about 5 to about 50% wt.
[0026] Typically, as the amount of water increases above about 20%
wt, the amount of corrosion increases. Such corrosion can be
reduced through the use of a corrosion inhibitor. In an alternative
embodiment, such corrosion can be reduced through the addition of a
sulfur-containing polar cosolvent to the present compositions.
Thus, the present invention further provides a method of reducing
metal corrosion in an electronic device substrate during contact of
the substrate with an aqueous polymer striping composition material
including the step of adding a sulfur-containing polar solvent to
the stripping composition. In general, as the amount of such
sulfur-containing polar solvent is increased, the likelihood of
metal corrosion due to contact with aqueous polymer stripping
compositions is reduced. Thus, as the amount of water in a polymer
remover composition increases, it is preferred that the amount of
corrosion inhibitor, sulfur-containing polar solvent or both is
increased, and more preferably that the amount of sulfur-containing
polar solvent is increased. It is further preferred that as the
amount of water in a polymer remover is increased, the amount of
sulfur-containing polar solvent is increased proportionately.
Preferred stripping compositions of the present invention include
one or more corrosion inhibitors and one or more sulfur-containing
polar solvents. Suitable sulfur-containing cosolvents include, but
are not limited to, dimethylsulfoxide and sulfolane.
[0027] Any water-miscible amine may used in the present
compositions. Suitable water-miscible amines include, but are not
limited to, alkyleneamines such as ethylenediamine,
diethylenetriamine, triethylenetetraamine, propylenediamine and the
like; aminoalcohols such as aminoethylaminoethanol, ethanolamine,
diethanolamine, triethanolamine, monoisopropanolamine,
diisopropanolamine, 3-amino-1-propanol and the like.
Aminoethylaminoethanol, 3-amino-1-propanol, monoisopropanolamine
and ethylenediamine are preferred. Particularly suitable
water-miscible amines are those capable of chelating one or more
metal ions, such as ethylenediamine, diethylenetriamine,
triethylenetetraamine and 3-amino-1-propanol.
[0028] The water-miscible amines are typically used in an amount of
from about 5 to about 65% wt, based on the total weight of the
composition. Preferred amounts of the water-miscible amines are
from about 10 to about 60% wt and more preferably from about 20 to
about 50% wt. The water-miscible amines are generally commercially
available, such as from Aldrich (Milwaukee, Wis.), and may be used
without further purification.
[0029] Any polar solvent that is water-miscible and compatible with
the present compositions may be used. Suitable polar solvents
include polar aprotic solvents, dimethylformamide,
dimethylacetamide, .gamma.-butyrolactone and glycol ethers such as
(C.sub.1,-C.sub.6)alkyl ethers of (C.sub.2-C.sub.20)alkanediols or
di(C.sub.1-C.sub.6)alkyl ethers of (C.sub.2-C.sub.20)alkanediols.
Suitable polar aprotic solvents include, but are not limited to,
dimethyl sulfoxide and sulfolane, and preferably dimethyl
sulfoxide. Such polar aprotic solvents are generally commercially
available, such as from Aldrich (Milwaukee, Wis.), and may be used
without further purification.
[0030] 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. Suitable glycol ethers are those sold under the
DOWANOL tradename such as DOWANOL DPM, DOWANOL TPM, DOWANOL PNB,
and DOWANOL DPNB all available from Dow Chemical Company (Midland,
Mich.).
[0031] Typically, the polar solvent used in the present invention
is in the range of about 5 to about 50% wt, based on the total
weight of the composition. It is preferred that the amount of polar
solvent is in the range of about 10 to about 45% wt, more
preferably from about 10 to 35% wt and still more preferably from
about 15 to 25% wt.
[0032] Mixtures of polar solvents may be advantageously used in the
present invention. It is preferred that when a mixture of polar
solvents is used that at least one solvent is selected from
diemthylsulfoxide, sulfolane and dipropylene glycol monomethyl
ether. When more than one polar solvent is used in the present
invention, the solvents may be combined in any ratio, from about
99:1 to about 1:99 by weight.
[0033] It will be appreciated by those skilled in the art that one
or more secondary solvents may be used in the present compositions.
Such secondary solvents include, but are not limited to,
(C.sub.1-C.sub.6)alkylpyrrolidinones such as N-methylpyrrolidinone,
N-ethylpyrrolidinone, N-hydroxyethylpyrrolidinone and
N-cyclohexylpyrrolidinone.
[0034] The present compositions may additionally include one or
more other components, such as corrosion inhibitors, wetting agents
or surfactants, anti-freeze agents, viscosity modifiers and the
like, and preferably corrosion inhibitors or wetting agents.
Suitable corrosion inhibitors useful in the present invention
include, but are not limited to, catechol;
(C.sub.1-C.sub.6)alkylcatechol such as methylcatechol,
ethylcatechol and tert-butylcatechol; benzotriazole;
(C.sub.1-C.sub.10)alkylbenzotriazoles; 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, and more preferably
benzotriazole or tert-butylcatechol. When such corrosion inhibitors
are used they are typically present in an amount in the range of
about 0.01 to 10% wt, based on the total weight of the stripping
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 4% wt, and most preferably from about 1.5 to about 3% wt. It
is preferred that at least one corrosion inhibitor be used in the
stripping compositions of the present invention. It will also be
appreciated by those skilled in the art that more than one
corrosion inhibitor may be advantageously used. Such corrosion
inhibitors are generally commercially available from a variety of
sources, such as Aldrich Chemical Company (Milwaukee, Wis.).
[0035] Nonionic and anionic surfactants may be used with the
stripping compositions of the present invention. Nonionic
surfactants are preferred. Such surfactants are generally
commercially available. Typically, such surfactants are used in an
amount of from about 0.2 to about 5% wt, preferably from about 0.5
to about 5% wt, and more preferably from about 1.5 to about 3.5%
wt, based on the total weight of the composition.
[0036] Particularly suitable compositions include from about 5 to
about 65% wt of a polyhydric alcohol selected from 1,3-propanediol,
2-methyl-1,3-propanediol, butanediol or glycerol, from about 5 to
about 40% wt water, from about 5 to about 65% wt of one or more
water-miscible amines selected from aminoethylaminoethanol,
ethanolamine, diethanolamine, triethanolamine,
monoisopropanolamine, diisopropanolamine, ethylenediamine,
diethylenetriamine and triethylenetetraamine, from about 5 to about
50% wt of one or more polar solvents selected from dimethyl
sulfoxide, sulfolane, 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, and dipropylene glycol mono-n-butyl ether, and from
about 0.2 to about 5% wt of a corrosion inhibitor selected from
catechol, (C.sub.1-C.sub.6)alkylcatechol, benzotriazole or
(C.sub.1-C.sub.10)alkylbenzotriazoles.
[0037] The compositions of the present invention may be prepared by
combining the one or more polyhydric alcohols, water, one or more
water-miscible amines, one or more polar solvents and one or more
optional components such as corrosion inhibitors or wetting agents,
in any order. It is preferred that the water-miscible amine is
dissolved in water and polyhydric alcohol mixture along with the
polar solvent followed by and any other optional components.
[0038] The compositions of the present invention are suitable for
removing polymeric material from a substrate. Suitable polymeric
material that can be removed by the present invention is any
residue from photoresists, soldermasks, organic antireflective
coatings, and the like. Typical polymeric antireflective coatings
include a chromophore, a polymeric binder and one or more
cross-linking agents. The compositions of the present invention are
particularly useful in removing the polymeric residue present after
plasma etching, reactive ion etching and ion milling of materials,
such as photoresists. Such polymeric residue remaining after plasma
etching, reactive ion etching and ion milling is typically
organometallic polymeric residue. Such organometallic residue is
typically referred to as "sidewall polymer."
[0039] Polymeric residue on a substrate may be removed by
contacting the substrate with a composition of the present
invention. The substrate may be contacted with the compositions of
the present invention by any known means, such as placing the
coated wafers in a hot bath of the stripping solvent, like a wet
chemical bench, or by putting the wafers in a spray equipment
chamber such as that available from Semitool, Inc. (Kalispell,
Mont.), followed by a deionized water spin, rinse and dry
process.
[0040] An advantage of the process of the present invention is that
lower temperatures may be used than those used with known stripping
compositions. Typically, the polymeric residue removal process of
the present invention may be carried out at any temperature, such
as from room temperature up to about 100.degree. C., preferably
from about 35.degree. to about 90.degree. C., more preferably from
about 50.degree. C. to about 85.degree. C., and most preferably
from about 70.degree. to about 80.degree. C. The polymer to be
removed is typically contacted with the present compositions for a
period of time sufficient to at least partially remove the polymer
residue. Typically, the polymer to be removed is contacted with the
present compositions for up to 60 minutes, preferably up to 45
minutes and more preferably from about 5 to about 30 minutes.
[0041] Thus, the present invention provides a method for
manufacturing an electronic device including a substrate containing
one or more metals and one or more polymeric materials, including
the steps of contacting the polymeric material to be removed with a
composition including one or more polyhydric alcohols, water, one
or more water-miscible amines, and one or more polar solvents for a
period of time sufficient to remove the polymeric material and
rinsing the substrate.
[0042] The present compositions are free of hydroxylamine and
metal-ions. It is preferred that the present compositions are free
of acid-type chelating agents such as ethylenediaminetetraacetic
acid, and free of alkylpyrrolidones such as N-methylpyrrolidone. It
is also preferred that the present compositions are free of
tetraalkylammonium hydroxide such as tetramethylammonium hydroxide.
It is further preferred that the present compositions are free of
alkali metal hydroxide, fluoride ion and amino acids. It is still
further preferred that the present compositions are free of a
chelating reagent comprising a mono- or poly-valent acid type
ligand covalently bonded to a polymeric or oligomeric backbone. In
general, the present compositions are alkaline and preferably have
a pH in the range of about 9 to about 11.
[0043] The present compositions are also useful in the manufacture
of magnetic thin film heads and opto-electronic devices. Thus, the
present invention provides a method for manufacturing magnetic thin
film heads and opto-electronic devices including the steps of
contacting a magnetic thin film head precursor or opto-electronic
device containing polymeric material to be removed with a
composition including one or more polyhydric alcohols, water, one
or more water-miscible amines, and one or more polar solvents for a
period of time sufficient to remove the polymeric material and
rinsing the substrate.
[0044] An advantage of the compositions of the present invention is
they are highly effective in removing post plasma etch residues
when other conventional strippers are not capable of removing such
residues. Furthermore the present compositions provide stripping
baths having prolonged stripping capacity and are substantially
non-corrosive to substrates containing metals, particularly copper,
copper alloys, tungsten, gallium and gallium alloys. Another
advantage of the compositions of the present invention is that they
are highly effective in complete removal of the post ash residues
of the deep UV photoresist coated on a layer of hard to remove
organic antireflective coating polymer. It is well known in the
industry that such organic antireflective coating residues that are
cross-linked polymeric material are very difficult to clean by
conventional resist strippers.
[0045] The compositions of the present invention are extremely
effective in removing post plasma etch polymers from different
substrates on silicon wafers, flat panel display plates and any
other device that has undergone dry plasma etch process.
[0046] 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
[0047] This example illustrates the results of polymer removal
capability of compositions of the present invention. The stripping
compositions evaluated are reported in Table 1.
Aluminum-copper-silicon ("Al--Cu--Si") wafers (8 inch, 20 cm) were
coated with UV-86 or UVN-110 brand series of deep UV photoresist
(available from Shipley Company, Marlborough, Mass.). The
photoresist was hard baked, processed and then plasma etched using
a typical dry etch process on a commercially available plasma
etcher followed by an oxygen plasma ash process. The wafers were
then immersed in a 500 ml bath of the stripping composition which
was heated at 85.degree. C. Following immersion for 20 minutes, the
wafers were then rinsed with deionized ("DI") water and dried under
a stream of nitrogen. The wafers were then evaluated for remaining
polymer residues by scanning electron microscopy ("SEM") using a
JEOL 6320 field emission scanning electron microscope (FE-SEM). A
number of the wafers having titanium nitride-aluminum-titanium
nitride layers were evaluated for sidewall polymer removal. Other
of the wafers were evaluated to contavt via polymer removal. The
stripping results are reported in Table 2.
1TABLE 1 Sample Composition 1 25% MP-diol/38% AEEA/15% DPM/20%
H.sub.2O/2% TBC 2 25% MP-diol/35% AEEA/20% DMSO/18% H.sub.2O/2% TBC
3 30% MP-diol/35% MIPA/18% DPM/15% H.sub.2O/2% TBC 4 30%
MP-diol/30% AEEA/20% DPM/18% H.sub.2O/2% BTA 5 22% MP-diol/38%
MIPA/15% Sulfolane/22.5% H.sub.2O/2.5% BTA 6 25% MP-diol/35%
MIPA/18% DMSO/15% H.sub.2O/2% BTA 7 6% MP-diol/40% EDA/25% DMSO/25%
H.sub.2O/4% TBC 8 6% MP-diol/45% EDA/25% DMSO/20% H.sub.2O/4% TBC 9
9% PDO/42% AMP/24% DMSO/22% H.sub.2O/3% BTA 10 5% MP-diol/35%
EDA/30% DMSO/25% H.sub.2O/5% TBC 11 8% MP-diol/42% MIPA/22%
Sulfolane/24% H.sub.2O/4% BTA 12 6% PDO/40% EDA/25% DMSO/25%
H.sub.2O/4% TBC 13 5% MP-diol/30% EDA/35% DMSO/25% H.sub.2O/5% TBC
14 10% MP-diol/40% AEEA/22% DMSO/25% H.sub.2O/3% TBC
[0048] Samples 1-6 and 14 were particularly suitable for the
stripping or removal of polymeric material from conventional
processes, including sidewall polymer resulting from conventional
plasma etching. Samples 7-13 were particularly suitable for use in
removing polymeric residue from substrates that were over-etched
with fluorine-rich higher density plasmas. Such plasmas generate
particularly thick and difficult to remove sidewall polymers.
2TABLE 2 TiN/Al/TiN Stripping Results Sample (Sidewall Polymers)
(Contact Via Polymer) 1 Polymer 95-98% removed Polymer 100% removed
2 Polymer 100% removed Polymer 100% removed (Excellent) (Excellent)
3 Polymer 95-98% removed Polymer 95% removed 4 Polymer 95-98%
removed Polymer 95% removed 5 Polymer 95-98% removed Polymer 100%
removed 6 Polymer 100% removed Polymer 100% removed (Excellent)
(Excellent) 7 Polymer 100% removed/ Polymer 100% removed no
corrosion 8 Polymer 100% removed Polymer 100% removed
(Excellent)/no corrosion (Excellent) 9 Polymer 95-98% removed/
Polymer 95% removed slight Al corrosion 10 Polymer 100% removed
Polymer 100% removed (Excellent)/no corrosion 11 Polymer 95-98%
removed Polymer 98% removed 12 Polymer 100% removed Polymer 100%
removed (Excellent)/no corrosion (Excellent)
[0049] The above data clearly show that the compositions of the
present invention are effective in removing polymeric material from
substrates, particularly post plasma etch polymeric material and
fluorine/aluminum rich organometallic sidewall polymer resulting
from excessive over etching with fluorinated plasma.
EXAMPLE 2
[0050] The effect of DI water concentration in the stripper
compositions was determined. A stripper composition pre-mix
including 40% wt AEEA, 33% wt MP-diol, 25% wt DMSO and 2 % wt
tert-butylcatechol was prepared. This pre-mix was combined with DI
water in varying amounts and the compositions used to remove
polymeric material from a variety of wafers. After contact with the
stripping compositions, the wafers were rinsed, dried and evaluated
for corrosion of aluminum, copper, titanium and titanium nitride
layers. The results are reported in Table 3. Each of the stripping
compositions had a pH in the range of 10-11.
3TABLE 3 Polymer Pre-Mix DI Water Removing Al Cu Ti, Ti/N (%) (%)
Efficacy Corrosion Corrosion Corrosion 85 15 Fair None None None
detected detected detected 82.5 17.5 Excellent None Minor None
detected attack detected 80 20 Good Slight Slight None detected 75
25 Fair Moderate Moderate None detected 70 30 Poor Corrosion
Corrosion Minor undercut
[0051] The above data show that the when the amount of water in the
present compositions is high, that is about 25% wt or greater,
corrosion of sensitive metal layers starts to occur. Thus, either
additional corrosion inhibitor, sulfur-containing polar solvent or
both is required to reduce such corrosion.
EXAMPLE 3
[0052] Two of the compositions prepared according to Example 1 were
evaluated for their compatibility with various thin metal
substrates. A variety of wafers containing one or more layers of
aluminum-silicon ("Al--Si"), titanium ("Ti"), titanium nitride
("TiN"), copper ("Cu") and tungsten/titanium-tungsten ("W/Ti--W")
were immersed in the stripping solutions for 60 minutes at
85.degree. C. The samples were then evaluated for loss of metal.
The results are reported in Table 4 as etch rates for each
metal.
4TABLE 4 Sample Al-Si Ti TiN Cu W/Ti-W 2 3-4 .ANG./min <1
.ANG./min <1 .ANG./min 2-3 .ANG./min 3-4 .ANG./min 3 3-4
.ANG./min <1 .ANG./min <1 .ANG./min 2-3 .ANG./min 3-4
.ANG./min 8 <1 .ANG./min <1 .ANG./min <1 .ANG./min 1-2
.ANG./min 1-2 .ANG./min 10 <1 .ANG./min <1 .ANG./min <1
.ANG./min 1-2 .ANG./min 1-2 .ANG./min
[0053] These data clearly show that the compositions of the present
invention do not significantly corrode sensitive metal layers.
EXAMPLE 4
[0054] Three of the compositions prepared according to Example 1
were evaluated for their compatibility with various dielectric
materials. A variety of wafers containing one or more layers of
silicon ("Si"), silicon dioxide ("SiO.sub.2"), and
hydridosilsesquioxane ("HSQ") were immersed in the stripping
solutions for 30 minutes at 85.degree. C. The samples were then
evaluated for attack on the dielectric material layers. The results
are reported in Table 5.
5TABLE 5 Sample Si SiO.sub.2 HSQ 1 HSQ 2 1 No attack No attack No
attack No attack 2 No attack No attack No attack No attack 3 Slight
attack No attack No attack Slight attack 8 No attack No attack No
attack No attack 10 No attack No attack No attack No attack
[0055] These data show that the present compositions are compatible
with a variety of dielectric materials use din the manufacture of
electronic devices.
EXAMPLE 5
[0056] Samples 2 and 6 from Example 1 and three commercially
available stripping compositions, Comparatives C-1, C-2 and C-3,
were evaluated from their copper compatibility. The comparative
compositions are reported in Table 6.
6TABLE 6 Sample Composition C-1 25% Hydroxylamine/62.5%
diglycolamine/12.5% H2O/ 5% catechol C-2 25% Hydroxylamine/60%
monoethanolamine/10% H2O/ 5% catechol C-3
N-methylpyrrolidone/ethyleneamine
[0057] Comparative samples C-1, C-2 and C-3 are commercially
available stripping products.
[0058] Wafer chips, 2 inch.times.2 inch (5 cm.times.5 cm),
containing electroplated copper (100% Cu) were heated in 100 ml of
a stripper composition at 75.degree. C. for 30 minutes. The copper
plated chip was then moved and the stripper composition was tested
for dissolved copper using a Hewlett Packard inductively coupled
plasma mass spectrometer (HP-4500 ICP-MS) with cold shield plasma
method. The amount of copper in the stripping solutions is reported
in Table 7 in parts per billion ("ppb"). The etch rates are also
reported.
7TABLE 7 Sample Cu Level Cu Etch Rate C-1 7865 ppb -- C-2 8640 ppb
-- C-3 11060 ppb -- 2 92 ppb <1 .ANG./min 6 96 ppb <1
.ANG./min
[0059] These data clearly show the compositions of the present
invention are more compatible with copper than known stripping
compositions.
EXAMPLE 6
[0060] Sample 2 from Example 1 is used to remove polymeric material
from a wafer containing an indium tin oxide/tantalum ("ITO/Ta")
layer on a glass flat panel display substrate. No major corrosion
on any of the metal layers is seen.
EXAMPLE 7
[0061] Sample 2 from Example 1 is used to remove polymeric material
from a wafer containing a niobium/aluminum/niobium ("Nb/Al/Nb")
layer. No major corrosion on any of the metal layers is seen.
EXAMPLE 8
[0062] Magneto-resistive and giant magneto-resistive head wafers
containing aluminum oxide ("Al.sub.2O.sub.3") thin films are
contacted with various stripper compositions for 30 minutes. The
lowest level of aluminum is seen in Sample 2 from Example 1,
indicating the lowest amount of corrosion.
EXAMPLE 9
[0063] Sample wafers having high aspect ratio (8:1) vias with side
wall polymers due to dry etching were immersed in a heated
(85.degree. C.) stripping bath of Sample 2. The wafers were
immersed in the composition for 30 minutes, removed from the bath,
rinsed with DI water and spin dried. A cross section SEM analysis
was conducted to examine the cleanliness of the via side walls and
corrosion on the Al contact layers. No visible sign of polymer
residue was found nor was any sign of corrosion observed.
EXAMPLE 10
[0064] The polymer removing capabilities of the compositions of the
invention were compared to those of hydroxylamine-containing
compositions. A wafer containing highly oxidized over-etched
sidewall polymer in vias was obtained. The wafer contained sidewall
polymer that was very difficult to remove. FIG. 1 is a SEM showing
the sidewall polymer in a via in the wafer. The wafer was first
broken into identical pieces, and then the pieces were contacted
with a stripping bath to remove the polymer.
[0065] Wafer piece A was immersed in a stripping bath of Sample 13
from Example 1 at 90.degree. C. for 40 minutes. The wafer was
removed from the bath, rinsed with DI water and spin dried. A cross
section SEM analysis was conducted to examine the cleanliness of
the via side walls and corrosion of the metal contact layers, and
is shown in FIG. 2. No visible sign of polymer residue was found
nor was any sign of undercut or corrosion observed.
[0066] Wafer piece B was immersed in a stripping bath of Sample 14
from Example 1 at 90.degree. C. for 40 minutes. The wafer was
removed from the bath, rinsed with DI water and spin dried. A cross
section SEM analysis was conducted to examine the cleanliness of
the via side walls and corrosion of the metal contact layers.
Sidewall polymer remained after the stripping treatment.
[0067] Wafer piece C was immersed in a conventional stripping bath
containing hydroxylamine, water, alkanolamine and a corrosion
inhibitor (comparative) at 70.degree. C. for 30 minutes. The wafer
was removed from the bath, rinsed with DI water and spin dried. A
cross section SEM analysis was conducted to examine the cleanliness
of the via side walls and corrosion of the metal contact layers,
and is shown in FIG. 3. No visible sign of polymer residue was
found, however some corrosion of the metal contact layer was
observed.
[0068] These data clearly indicate that the compositions of the
present invention containing amines that are not alkanolamines are
particularly effective at removing very difficult to remove
sidewall polymers, such as highly oxidized over-etched via
polymers. These data also show that the compositions of the
invention are as effective at removing difficult sidewall polymers
as hydroxylamine-containing strippers, but without the problems of
hydroxylamine-containing strippers. These data further show that
the present compositions are less corrosive than
hydroxylamine-containing polymer removers.
* * * * *