U.S. patent application number 11/552808 was filed with the patent office on 2007-11-01 for removal of high-dose ion-implanted photoresist using self-assembled monolayers in solvent systems.
Invention is credited to Thomas H. Baum, Michael B. Korzenski, Pamela M. Visintin.
Application Number | 20070251551 11/552808 |
Document ID | / |
Family ID | 39324941 |
Filed Date | 2007-11-01 |
United States Patent
Application |
20070251551 |
Kind Code |
A1 |
Korzenski; Michael B. ; et
al. |
November 1, 2007 |
REMOVAL OF HIGH-DOSE ION-IMPLANTED PHOTORESIST USING SELF-ASSEMBLED
MONOLAYERS IN SOLVENT SYSTEMS
Abstract
A method and self assembled monolayer (SAM)-containing
compositions for removing bulk and hardened photoresist material
from microelectronic devices have been developed. The
SAM-containing composition includes at least one solvent, at least
one catalyst, at least one SAM component, and optionally a
surfactant. The SAM-containing compositions effectively remove the
hardened photoresist material while simultaneously passivating the
underlying silicon-containing layer(s) in a one step process.
Inventors: |
Korzenski; Michael B.;
(Danbury, CT) ; Visintin; Pamela M.; (Red Hook,
NY) ; Baum; Thomas H.; (Fairfield, CT) |
Correspondence
Address: |
MOORE & VAN ALLEN PLLC
P.O. BOX 13706
Research Triangle Park
NC
27709
US
|
Family ID: |
39324941 |
Appl. No.: |
11/552808 |
Filed: |
October 25, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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PCT/US06/13430 |
Apr 10, 2006 |
|
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|
11552808 |
Oct 25, 2006 |
|
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60671851 |
Apr 15, 2005 |
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Current U.S.
Class: |
134/41 ;
257/E21.255; 510/109 |
Current CPC
Class: |
B82Y 10/00 20130101;
B82Y 30/00 20130101; G03F 7/427 20130101; H01L 21/31133 20130101;
G03F 7/422 20130101 |
Class at
Publication: |
134/041 ;
510/109 |
International
Class: |
C23G 1/02 20060101
C23G001/02 |
Claims
1. (canceled)
2. A method of removing bulk and hardened photoresist material from
a microelectronic device having said photoresist material thereon,
said method comprising contacting the microelectronic device with a
SAM-containing composition for sufficient time and under sufficient
contacting conditions to at least partially remove said photoresist
material from the microelectronic device, wherein the
SAM-containing composition includes at least one solvent, at least
one catalyst, at least one SAM component, and optionally at least
one surfactant.
3. The method of claim 2, wherein said contacting is carried out at
conditions selected from the group consisting of: time of from
about 1 minute to about 60 minutes; temperature in a range of from
about 30.degree. C. to about 80.degree. C., and combinations
thereof.
4. (canceled)
5. The method of claim 2, wherein the solvent comprises at least
one solvent selected from the group consisting of toluene, decane,
octane, dodecane, pentane, hexane, tetrahydrofuran (THF), carbon
dioxide, methanol, ethanol, isopropanol, N-methylpyrrolidinone,
N-octylpyrrolidinone, N-phenylpyrrolidinone, dimethylsulfoxide
(DMSO), sulfolane, ethyl lactate, ethyl acetate, toluene, acetone,
butyl carbitol, monoethanolamine, butyrol lactone, diglycol amine,
alkyl ammonium fluoride, .gamma.-butyrolactone, butylene carbonate,
ethylene carbonate, propylene carbonate, and mixtures thereof;
wherein the catalyst comprises an amine selected from the group
consisting of trimethylamine, triethylamine, butylamine, pyridine,
and combinations thereof; and wherein the SAM component comprises a
silane selected from the group consisting of: (RO).sub.3SiX,
(RO).sub.2SiX.sub.2, (RO)SiX.sub.3, (R).sub.3SiX,
(R).sub.2SiX.sub.2, and (R)SiX.sub.3, where X=F, Cl, Br and I, and
R=methyl, ethyl, propyl, butyl, octyl, decyl, and dodecyl;
fluorinated derivatives thereof; and combinations thereof.
6. The method of claim 2, wherein the mole ratio of SAM(s) relative
to catalyst(s) in a liquid SAM-containing composition is in a range
from about 1:10 to about 5:1 and the mole ratio of SAM(s) relative
to solvent(s) is in a range from about 1:200 to about 1:50.
7. The method of claim 2, wherein the microelectronic device
comprises an article selected from the group consisting of
semiconductor substrates, flat panel displays, and
microelectromechanical systems (MEMS).
8. The method of claim 2, wherein the bulk and hardened photoresist
materials comprise dopant ions selected from the group consisting
of arsenic ions, boron ions, phosphorous ions, indium ions, and
antimony ions.
9. The method of claim 2, wherein the contacting comprises a
process selected from the group consisting of: spraying the
SAM-containing composition on a surface of the microelectronic
device; dipping the microelectronic device in a sufficient volume
of SAM-containing composition; contacting a surface of the
microelectronic device with another material that is saturated with
the SAM-containing composition; contacting the microelectronic
device with a circulating SAM-containing composition; contacting
the microelectronic device with a continuous flow of the
SAM-containing composition; and contacting the microelectronic
device surface with a static volume of the SAM-containing
composition for a continued period of time.
10. The method of claim 2, further comprising rinsing the
microelectronic device following contact with the SAM-containing
composition.
11. The method of claim 2, wherein the at least one SAM component
and the at least one catalyst are present in amounts effective to
simultaneously passivate a silicon-containing layer on said
microelectronic device and remove bulk and hardened photoresist
material from the microelectronic device having said material
thereon.
12. The method of claim 11, wherein the silicon-containing layer
comprises a silicon-containing compound selected from the group
consisting of silicon; silicon dioxide; TEOS; silicon nitride;
silicon-containing organic polymers; silicon-containing hybrid
organic/inorganic materials; organosilicate glass (OSG);
fluorinated silicate glass (FSG); carbon-doped oxide (CDO) glass;
and combinations thereof.
13. The method of claim 11, wherein the underlying
silicon-containing layer has a contact angle in a range from about
60 degrees to about 120 degrees following formation of the
SAM-passivating layer.
14. The method of claim 2, further comprising removing a
SAM-passivating layer from the microelectronic device with a
depassivating composition following at least partial removal of
said photoresist material from the microelectronic device.
15. The method of claim 14, wherein the depassivating composition
comprises compounds selected from the group consisting of
pyridine/HF complexes, pyridine/HCl complexes, pyridine/HBr
complexes, triethylamine/HF complexes, fluorosilicic acid,
hydrofluoric acid, tetrafluoroboric acid, triethylamine/HCl
complexes, triethylamine/formic acid complexes, peroxide
derivatives thereof, concentrated HCl, ammonium hydroxide, and
combinations thereof.
16. The method of claim 2, wherein the solvent comprises dense
carbon dioxide.
17. The method of claim 16, wherein said contacting comprises
conditions selected from the group consisting of: pressure in a
range of from about 1500 to about 4500 psi; time in a range of from
about 5 to about 30 minutes; temperature in a range of from about
40.degree. C. to about 75.degree. C.; and combinations thereof.
18. (canceled)
19. (canceled)
20. (canceled)
21. A method of removing a self assembled monolayer (SAM)
passivating layer from a microelectronic device with a
depassivating composition, wherein the depassivating composition
comprises compounds selected from the group consisting of
pyridine/HF complexes, pyridine/HCl complexes, pyridine/HBr
complexes, triethylamine/HF complexes, fluorosilicic acid,
hydrofluoric acid, tetrafluoroboric acid, triethylamine/HCl
complexes, triethylamine/formic acid complexes, peroxide
derivatives thereof, concentrated HCl, ammonium hydroxide, and
combinations thereof.
22. A self assembled monolayer (SAM)-containing composition,
comprising at least one solvent, at least one catalyst, at least
one SAM component, and optionally at least one surfactant, wherein
said SAM-containing composition is suitable for removing bulk and
hardened photoresist material from a microelectronic device having
said photoresist material thereon.
23. The SAM-containing composition of claim 22, wherein the mole
ratio of SAM(s) relative to catalyst(s) in a liquid SAM-containing
composition is in a range from about 1:10 to about 5:1, and the
mole ratio of SAM(s) relative to solvent(s) is in a range from
about 1:200 to about 1:50.
24. The SAM-containing composition of claim 22, wherein the solvent
comprises at least one non-polar solvent selected from the group
consisting of toluene, decane, dodecane, octane, pentane, hexane,
tetrahydrofuran (THF), carbon dioxide, and mixtures thereof.
25. The SAM-containing composition of claim 24, further comprising
an additional solvent selected from the group consisting of
methanol, ethanol, isopropanol, N-methylpyrrolidinone,
N-octylpyrrolidinone, N-phenylpyrrolidinone, dimethylsulfoxide
(DMSO), sulfolane, ethyl lactate, ethyl acetate, toluene, acetone,
butyl carbitol, monoethanolamine, butyrol lactone, diglycol amine,
alkyl ammonium fluoride, .gamma.-butyrolactone, butylene carbonate,
ethylene carbonate, propylene carbonate, and mixtures thereof.
26. The SAM-containing composition of claim 22, wherein the solvent
comprises toluene.
27. The SAM-containing composition of claim 22, wherein the solvent
comprises dense carbon dioxide.
28. The SAM-containing composition of claim 22, wherein the SAM
component comprises a silane selected from the group consisting of:
(RO).sub.3SiX, (RO).sub.2SiX.sub.2, (RO)SiX.sub.3, (R).sub.3SiX,
(R).sub.2SiX.sub.2, and (R)SiX.sub.3, where X=F, Cl, Br and I, and
R=methyl, ethyl, propyl, butyl, octyl, decyl, and dodecyl;
fluorinated derivatives thereof; and combinations thereof.
29. The SAM-containing composition of claim 22, wherein the SAM
component comprises an alkylchlorosilane selected from the group
consisting of Cl.sub.3SiMe, Cl.sub.2SiMe.sub.2, and
ClSiMe.sub.3.
30. The SAM-containing composition of claim 22, wherein the
catalyst comprises an amine selected from the group consisting of
trimethylamine, triethylamine, butylamine, pyridine, and
combinations thereof.
31. The SAM-containing composition of claim 22, comprising at least
one surfactant.
32. The SAM-containing composition of claim 22, wherein the
surfactant comprises a surfactant species selected from the group
consisting of fluoroalkyl surfactants, polyethylene glycols,
polypropylene glycols, polyethylene glycol ethers, polypropylene
glycol ethers, carboxylic acid salts, dodecylbenzenesulfonic acid,
dodecylbenzenesulfonic acid salts, polyacrylate polymers,
dinonylphenyl polyoxyethylene, silicone polymers, modified silicone
polymers, acetylenic diols, modified acetylenic diols,
alkylammonium salts, modified alkylammonium salts, and combinations
thereof.
33. The SAM-containing composition of claim 22, wherein the
composition comprises toluene, Cl.sub.3SiMe and triethylamine.
34. The SAM-containing composition of claim 22, wherein the
microelectronic device comprises an article selected from the group
consisting of semiconductor substrates, flat panel displays, and
microelectromechanical systems (MEMS).
35. The SAM-containing composition of claim 22, wherein the bulk
and hardened photoresist materials comprise dopant ions selected
from the group consisting of arsenic ions, boron ions, phosphorous
ions, indium ions and antimony ions.
36. The SAM-containing composition of claim 22, wherein the at
least one SAM component and the at least one catalyst are present
in amounts effective to simultaneously passivate a
silicon-containing layer on said microelectronic device and remove
bulk and hardened photoresist material from the microelectronic
device having said material thereon.
37. The SAM-containing composition of claim 36, wherein the
silicon-containing layer comprises a silicon-containing compound
selected from the group consisting of silicon; silicon dioxide;
TEOS; silicon nitride; silicon-containing organic polymers;
silicon-containing hybrid organic/inorganic materials;
organosilicate glass (OSG); fluorinated silicate glass (FSG);
carbon-doped oxide (CDO) glass; and combinations thereof.
38. The SAM-containing composition of claim 27, wherein the carbon
dioxide is supercritical.
39. The SAM-containing composition of claim 22, further comprising
photoresist residue material, wherein the photoresist comprises
bulk photoresist, hardened photoresist, or combinations
thereof.
40. The SAM-containing composition of claim 39, wherein the
photoresist comprises an ion selected from the group consisting of
boron ions, arsenic ions, phosphorus ions, indium ions, antimony
ions, and combinations thereof.
41. A kit comprising, in one or more containers, SAM-containing
composition reagents, wherein the SAM-containing composition
comprises at least one solvent, at least one catalyst, at least one
SAM component, and optionally at least one surfactant, and wherein
the kit is adapted to form a SAM-containing composition suitable
for removing bulk and hardened photoresist material from a
microelectronic device having said photoresist material
thereon.
42. A method of manufacturing a microelectronic device, said method
comprising contacting the microelectronic device with the
SAM-containing composition of claim 22 for sufficient time to at
least partially remove bulk and hardened photoresist material from
the microelectronic device having said material thereon.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to self-assembled monolayer
(SAM)-containing compositions useful for the removal of bulk and
hardened photoresist from the surface of microelectronic devices,
and methods of using said compositions for removal of same.
DESCRIPTION OF THE RELATED ART
[0002] As semiconductor devices have become more integrated and
miniaturized, ion implantation has been extensively employed during
front-end-of-line (FEOL) processing to accurately control impurity
distributions in the microelectronic device and to add dopant
atoms, e.g., As, B and P, to the exposed device layers. The
concentration and depth of the dopant impurity is controlled by
varying the dose of the dopant, the acceleration energy, and the
ion current. Prior to subsequent processing, the ion-implanted
photoresist layer must be removed. Various processes have been used
in the past for the removal of said hardened photoresist including,
but not limited to, wet chemical etching processes, e.g., in a
mixed solution of sulphuric acid and hydrogen peroxide, and dry
plasma etching processes, e.g., in an oxygen plasma ashing
process.
[0003] Unfortunately, when high doses of ions (e.g., doses greater
than about 1.times.10.sup.15 atoms cm.sup.-2), at low (5 keV),
medium (10 keV) and high (20 keV) implant energy, are implanted in
the desired layer, they are also implanted throughout the
photoresist layer, particularly the exposed surface of the
photoresist, which becomes physically and chemically rigid. The
rigid ion-implanted photoresist layer, also referred to as the
carbonized region or "crust," has proven difficult to remove.
[0004] Presently, the removal of the ion-implanted photoresist and
other contaminants is usually performed by a plasma etch method
followed by a multi-step wet strip process, typically using
aqueous-based etchant formulations to remove photoresist, post-etch
residue and other contaminants. Wet strip treatments in the art
generally involve the use of strong acids, bases, solvents, and
oxidizing agents. Disadvantageously, however, wet strip treatments
also etch the underlying silicon-containing layers, such as the
substrate and gate oxide, and/or increase the gate oxide
thickness.
[0005] As the feature sizes continue to decrease, satisfying the
aforementioned removal requirements becomes significantly more
challenging using the aqueous-based etchant formulations of the
prior art. Water has a high surface tension which limits or
prevents access to the smaller image nodes with high aspect ratios,
and therefore, removing the residues in the crevices or grooves
becomes more difficult. In addition, aqueous-based etchant
formulations often leave previously dissolved solutes behind in the
trenches or vias upon evaporative drying, which inhibit conduction
and reduce device yield. Furthermore, underlying porous low-k
dielectric materials do not have sufficient mechanical strength to
withstand the capillary stress of high surface tension liquids such
as water, resulting in pattern collapse of the structures. Aqueous
etchant formulations can also strongly alter important material
properties of the low-k materials, including dielectric constant,
mechanical strength, moisture uptake, coefficient of thermal
expansion, and adhesion to different substrates.
[0006] Therefore, it would be a significant advance in the art to
provide an improved composition that overcomes the deficiencies of
the prior art relating to the removal of bulk and hardened
photoresist from microelectronic devices. The improved composition
shall effectively remove bulk and hardened photoresist in a
one-step or multi-step process, without the need for a plasma etch
step and without substantially over-etching the underlying
silicon-containing layer(s).
SUMMARY OF THE INVENTION
[0007] The present invention relates to self-assembled monolayer
(SAM)-containing compositions useful for the removal of bulk and
hardened photoresist from the surface of microelectronic devices,
methods of making and methods of using said compositions for
removal of same, and improved microelectronic devices made using
the same.
[0008] In one aspect, the invention relates to a self assembled
monolayer (SAM)-containing composition, comprising at least one
solvent, at least one catalyst, at least one SAM component, and
optionally at least one surfactant, wherein said SAM-containing
composition is suitable for removing bulk and hardened photoresist
material from a microelectronic device having said photoresist
material thereon.
[0009] In another aspect, the present invention relates to a kit
comprising, in one or more containers, SAM-containing composition
reagents, wherein the SAM-containing composition comprises at least
one solvent, at least one catalyst, at least one SAM component, and
optionally at least one surfactant, and wherein the kit is adapted
to form a SAM-containing composition suitable for removing bulk and
hardened photoresist material from a microelectronic device having
said photoresist material thereon.
[0010] In a further aspect, the present invention relates to a
method of removing bulk and hardened photoresist material from a
microelectronic device having said photoresist material thereon,
said method comprising contacting the microelectronic device with a
SAM-containing composition for sufficient time and under sufficient
contacting conditions to at least partially remove said photoresist
material from the microelectronic device, wherein the
SAM-containing composition includes at least one solvent, at least
one catalyst, at least one SAM component, and optionally at least
one surfactant.
[0011] In a still further aspect, the present invention relates to
a method of removing bulk and hardened photoresist material from a
microelectronic device having said photoresist material thereon,
said method comprising contacting the microelectronic device with a
SAM-containing composition for sufficient time to at least
partially passivate a silicon-containing layer underlying the
photoresist material, and contacting the microelectronic device
with an etchant-containing removal composition to at least
partially remove said photoresist material from the microelectronic
device, wherein the SAM-containing composition comprises a
non-halide containing SAM component.
[0012] In another aspect, the present invention relates to a method
of removing bulk and hardened photoresist material from a
microelectronic device having said photoresist material thereon,
said method comprising contacting the microelectronic device with a
SAM-containing composition for sufficient time to at least
partially remove said photoresist material from the microelectronic
device, wherein the SAM-containing composition is devoid of an
etchant component.
[0013] In yet another aspect, the present invention relates to a
method of manufacturing a microelectronic device, said method
comprising contacting the microelectronic device with an
SAM-containing composition for sufficient time to at least
partially remove bulk and hardened photoresist material from the
microelectronic device having said photoresist material thereon,
wherein the SAM-containing composition includes at least one
solvent, at least one catalyst, at least one SAM component, and
optionally at least one surfactant, and optionally incorporating
said cleaned microelectronic device into a product.
[0014] Other aspects, features and embodiments of the invention
will be more fully apparent from the ensuing disclosure and
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIGS. 1A-1D are atomic force micrographs of the
microelectronic device surfaces at contacting times=1 min, 30 min,
1 hour and 15 hours, respectively, following contact of a
SAM-containing composition including 1 mmol Cl.sub.3SiMe and 2 mmol
Et.sub.3N in 10 mL of toluene, with the device surface at a
contacting temperature of 70.degree. C.
[0016] FIG. 2 illustrates the cleaning efficiency of a
SAM-containing composition of the present invention as a function
of temperature for four different microelectronic device layers
including a bulk blanketed photoresist layer (Bulk PR), a blanketed
ion-implanted photoresist layer (Crust), a bulk patterned
photoresist layer (Patterned PR) and a patterned ion-implanted
photoresist layer (Patterned Crust).
[0017] FIGS. 3A-3C are atomic force micrographs of the
microelectronic device surfaces following contact of a
SAM-containing composition including ClSiMe.sub.3 (FIG. 3A),
Cl.sub.2SiMe.sub.2 (FIG. 3B), and Cl.sub.3SiMe (FIG. 3C), in 2 mmol
Et.sub.3N in 10 mL of toluene, with the device surface at a
contacting temperature of 70.degree. C. for 30 min.
[0018] FIGS. 4A-4C are optical microscope images (FIG. 4A) and
scanning electron microscopic (SEM) images (FIGS. 4B-4C) of densely
patterned, ion implanted photoresist on a microelectronic device
surface.
[0019] FIGS. 5A-5C are optical microscope images of the
microelectronic device surfaces following contact of a
SAM-containing composition including ClSiMe.sub.3 (FIG. 5A),
Cl.sub.2SiMe.sub.2 (FIG. 5B), and Cl.sub.3SiMe (FIG. 5C), at
70.degree. C. for 30 min.
[0020] FIG. 6 illustrates the removal efficiency of a
SAM-containing composition of the present invention as a function
of SAM functionality for the four different microelectronic device
layers including a bulk blanketed photoresist layer (Bulk PR), a
blanketed ion-implanted photoresist layer (Crust), a bulk patterned
photoresist layer (Patterned PR) and a patterned ion-implanted
photoresist layer (Patterned Crust).
[0021] FIGS. 7A-7C are optical microscope images of the control
surface (FIG. 7A), the surface following cleaning and passivation
using a SAM-containing composition of the invention (FIG. 7B), and
the surface following depassivation according to the invention
(FIG. 7C).
[0022] FIGS. 8A-8E are scanning electron micrographs of the control
surface (FIG. 8A), the surface following cleaning and passivation
using a SAM-containing composition of the invention (FIG. 8B), the
surface following depassivation at a 90.degree. angle view (FIG.
8C) and a 60.degree. angle view (FIG. 8D), and a purposely
over-etched surface following depassivation (FIG. 8E).
DETAILED DESCRIPTION OF THE INVENTION, AND PREFERRED EMBODIMENTS
THEREOF
[0023] The present invention is based on the discovery of
self-assembled monolayer (SAM)-containing compositions that are
highly efficacious for the removal of bulk and hardened photoresist
from the surface of microelectronic devices, while maintaining the
integrity of the underlying silicon-containing layer(s).
[0024] "Bulk photoresist," as used herein, corresponds to the
non-carbonized photoresist on the microelectronic device surface,
specifically adjacent and below the hardened photoresist crust.
[0025] "Hardened photoresist" as used herein includes, but is not
limited to, photoresist that has been plasma etched, e.g., during
back-end-of-line (BEOL) dual-damascene processing of integrated
circuits, ion implanted, e.g., during front-end-of-line (FEOL)
processing to implant dopant species in the appropriate layers of
the semiconductor wafer, and/or any other methodology whereby a
carbonized or highly cross-linked crust forms on the exposed
surface of the bulk photoresist.
[0026] As used herein, "underlying silicon-containing" layer
corresponds to the layer(s) immediately below the bulk and/or the
hardened photoresist including: silicon; silicon oxide, including
gate oxides (e.g., thermally or chemically grown SiO.sub.2) and
TEOS; silicon nitride; and low-k silicon-containing materials. As
defined herein, "low-k silicon-containing material" corresponds to
any material used as a dielectric material in a layered
microelectronic device, wherein the material has a dielectric
constant less than about 3.5. Preferably, the low-k dielectric
materials include low-polarity materials such as silicon-containing
organic polymers, silicon-containing hybrid organic/inorganic
materials, organosilicate glass (OSG), TEOS, fluorinated silicate
glass (FSG), silicon dioxide, and carbon-doped oxide (CDO) glass.
It is to be appreciated that the low-k dielectric materials may
have varying densities and varying porosities.
[0027] "Microelectronic device" corresponds to semiconductor
substrates, flat panel displays, and microelectromechanical systems
(MEMS), manufactured for use in microelectronic, integrated
circuit, or computer chip applications. It is to be understood that
the term "microelectronic device" is not meant to be limiting in
any way and includes any substrate that will eventually become a
microelectronic device or microelectronic assembly.
[0028] As defined herein, "substantially over-etching" corresponds
to greater than about 10% removal, more preferably greater than
about 5% removal, and most preferably greater than about 2%
removal, of the adjacent underlying silicon-containing layer(s)
following contact, according to the process of the present
invention, of the SAM-containing compositions of the invention with
the microelectronic device having said underlying layer(s). In
other words, most preferably no more than 2% of the underlying
silicon-containing layer(s) are etched using the compositions of
the present invention for the prescribed times.
[0029] As used herein, "about" is intended to correspond to .+-.5%
of the stated value.
[0030] As used herein, "suitability" for removing bulk and hardened
photoresist material from a microelectronic device having said
photoresist material thereon, corresponds to at least partial
removal of said photoresist material from the microelectronic
device. Preferably, at least 90% of the photoresist material is
removed from the microelectronic device using the compositions of
the invention, more preferably, at least 95%, and most preferably
at least 99% of the photoresist material, is removed.
[0031] "Dense fluid," as used herein, corresponds to a
supercritical fluid or a subcritical fluid. The term "supercritical
fluid" is used herein to denote a material which is under
conditions of not lower than a critical temperature, T.sub.c, and
not less than a critical pressure, P.sub.c, in a
pressure-temperature diagram of an intended compound. The preferred
supercritical fluid employed in the present invention is CO.sub.2,
which may be used alone or in an admixture with another additive
such as Ar, NH.sub.3, N.sub.2, CH.sub.4, C.sub.2H.sub.4, CHF.sub.3,
C.sub.2H.sub.6, n-C.sub.3H.sub.8, H.sub.2O, N.sub.2O and the like.
The term "subcritical fluid" describes a solvent in the subcritical
state, i.e., below the critical temperature and/or below the
critical pressure associated with that particular solvent.
Preferably, the subcritical fluid is a high pressure liquid of
varying density.
[0032] Importantly, the SAM-containing compositions of the present
invention must possess good metal-containing material
compatibility, e.g., a low etch rate on the metal-containing
material. Metal-containing materials of interest include, but are
not limited to, copper, tungsten, cobalt, aluminum, tantalum,
titanium and ruthenium and silicides and nitrides thereof.
[0033] Self assembled monolayers (SAMs) are known to passivate
various surfaces, including, but not limited to, metals (e.g.,
copper, gold, etc), and oxides of titanium, hafnium, silicon, and
aluminum. SAMs include silanes having at least one leaving group,
e.g., a halide, said silane readily forming a covalent bond at an
oxygen group on a silicon-containing surface (i.e., via a
silylation reaction). The silanes themselves may further include
covalently bonded inert molecules, such as polyethylene glycol
(PEG), whereby following attachment with the silicon-containing
surface, the PEG-silane can block other molecules from binding with
said surface. PEG-silane SAMs are popular because they are thin
(i.e., non-bulky) and hydrophilic, and linkage of the PEG molecule
with the silicon-containing surface results in a non-sticky,
water-like layer. In contrast, alkylchlorosilanes may be used to
form a hydrophobic surface, if necessary.
[0034] Compositions of the invention may be embodied in a wide
variety of specific formulations, as hereinafter more fully
described.
[0035] In all such compositions, wherein specific components of the
composition are discussed in reference to weight percentage ranges
including a zero lower limit, it will be understood that such
components may be present or absent in various specific embodiments
of the composition, and that in instances where such components are
present, they may be present at concentrations as low as 0.01
weight percent, based on the total weight of the composition in
which such components are employed.
[0036] In one aspect, the invention relates to a liquid
SAM-containing composition useful in removing bulk and hardened
photoresist from a microelectronic device. The liquid composition
according to one embodiment comprises at least one SAM component,
optionally at least one solvent, optionally at least one catalyst,
and optionally at least one surfactant. The liquid composition
according to another embodiment comprises at least one SAM
component, at least one catalyst, optionally at least one solvent,
and optionally at least one surfactant. The liquid composition
according to yet another embodiment comprises at least one SAM
component, at least one solvent, at least one catalyst, and
optionally at least one surfactant. Importantly, depending on the
nature of the solvent chosen, the solvent may act concurrently as
the catalyst.
[0037] In one embodiment, the invention relates to a liquid
SAM-containing composition useful in removing bulk and hardened
photoresist from a microelectronic device, wherein the catalyst
concurrently acts as the solvent. The liquid composition according
to this embodiment comprises at least one catalyst, at least one
SAM component, and optionally at least one surfactant present in
the following ranges, based on the total weight of the composition:
TABLE-US-00001 component of % by weight catalyst(s) about 85.0% to
about 99.99% SAM(s) about 0.01% to about 10.0% Surfactant(s) 0% to
about 10.0%
[0038] In a particularly preferred embodiment, the invention
relates to a liquid SAM-containing composition useful in removing
bulk and hardened photoresist from a microelectronic device. The
liquid composition according to this embodiment comprises at least
one solvent, at least one catalyst, at least one SAM component, and
optionally at least one surfactant present in the following ranges,
based on the total weight of the composition: TABLE-US-00002
component of % by weight solvent(s) about 75.0% to about 99.98%
SAM(s) about 0.01% to about 10.0% catalyst(s) about 0.01% to about
10.0% Surfactant(s) 0% to about 10.0%
[0039] In one aspect, the range of mole ratios of SAM(s) relative
to catalyst(s) in the liquid SAM-containing composition is about
1:10 to about 5:1, more preferably about 1:5 to about 1:1; the
range of mole ratios of SAM(s) relative to liquid solvent(s) is
about 1:200 to about 1:50, more preferably about 1:125 to about
1:75; and the range of mole ratios of SAM(s) relative to
surfactant(s) (when present) is about 1:10 to about 5:1.
[0040] In the broad practice of the invention, the liquid
SAM-containing composition may comprise, consist of, or consist
essentially of at least one solvent, at least one catalyst, at
least one SAM component, and optionally at least one surfactant. In
general, the specific proportions and amounts of solvent(s),
catalyst(s), SAM component(s), and optional surfactant(s), in
relation to each other, may be suitably varied to provide the
desired removal action of the liquid SAM-containing composition for
the bulk and hardened photoresist and/or processing equipment, as
readily determinable within the skill of the art without undue
effort.
[0041] Solvent species useful in the compositions of the invention
may be non-polar or polar in nature. Illustrative non-polar species
include, but are not limited to, toluene, decane, dodecane, octane,
pentane, hexane, tetrahydrofuran (THF) and carbon dioxide
(subcritical or supercritical). Illustrative polar species include
methanol, ethanol, isopropanol, N-methylpyrrolidinone,
N-octylpyrrolidinone, N-phenylpyrrolidinone, dimethylsulfoxide
(DMSO), sulfolane, ethyl lactate, ethyl acetate, toluene, acetone,
methyl carbitol, butyl carbitol, hexyl carbitol, monoethanolamine,
butyrol lactone, diglycol amine, alkyl ammonium fluoride,
.gamma.-butyrolactone, butylene carbonate, ethylene carbonate, and
propylene carbonate and mixtures thereof. Preferably, the solvent
comprises a non-polar species. Toluene is especially preferred.
[0042] The SAM component may include alkoxyhalosilanes including
(RO).sub.3SiX, (RO).sub.2SiX.sub.2, (RO)SiX.sub.3, where X may be
the same as or different from one another and is selected from the
group consisting of F, Cl, Br or I, and RO may be the same as or
different from one another and is selected from the group
consisting of straight-chained or branched C.sub.1-C.sub.20 alkoxy
species such as methoxy, ethoxy, propoxy, etc., or combinations
thereof. Preferably, the SAM component includes alkylhalosilanes of
the nature (R).sub.3SiX, (R).sub.2SiX.sub.2, (R)SiX.sub.3, where X
may be the same as or different from one another and is selected
from the group consisting of F, Cl, Br or I, and R may be the same
as or different from one another and is selected from the group
consisting of straight-chained, branched or cyclic C.sub.1-C.sub.20
alkyl species such as methyl, ethyl, propyl, butyl, octyl, decyl,
dodecyl, etc., or combinations thereof. Fluorinated alkyl and
alkoxy derivatives may also be used. Preferably, the SAM component
includes alkylhalosilanes where X=Cl and R=methyl. In another
alternative, the SAM component has a PEG molecule attached
thereto.
[0043] Although not wishing to be bound by theory, the catalyst is
included in the composition of the invention to initiate the
silylation reaction and speed up the passivation of the underlying
silicon-containing layer(s). Preferably, the catalysts include
amines such as trimethylamine, triethylamine, butylamine, pyridine,
and any other nucleophilic compound that aids in the removal of a
halogen leaving group from the SAM component. It is thought that
the amine catalyst promotes an in situ silylation reaction, whereby
the SAM silane covalently attaches to oxygen atoms on the
underlying silicon-containing layer(s), with the simultaneous
generation of a protonated leaving group, e.g., HX. Accordingly,
the underlying silicon-containing layer is passivated by the
covalently bound silane, while the generated protonated leaving
group is available for removal of the hardened photoresist
material. Importantly, depending on the nature of the solvent
chosen, the solvent may act concurrently as the catalyst.
[0044] The liquid SAM-containing compositions of the invention may
further include a surfactant to assist in the removal of the resist
from the surface of the microelectronic device. Illustrative
surfactants include, but are not limited to, fluoroalkyl
surfactants, polyethylene glycols, polypropylene glycols,
polyethylene or polypropylene glycol ethers, carboxylic acid salts,
dodecylbenzenesulfonic acid or salts thereof, polyacrylate
polymers, dinonylphenyl polyoxyethylene, silicone or modified
silicone polymers, acetylenic diols or modified acetylenic diols,
alkylammonium or modified alkylammonium salts, as well as
combinations of the foregoing surfactants.
[0045] In a preferred embodiment, the liquid SAM-containing
composition includes less than about 1 wt. % water, more preferably
less than about 0.5 wt. % water, and most preferably less than
about 0.25 wt. % water, based on the total weight of the
composition. Further, preferably the at least one SAM component
does not undergo substantial polymerization at the microelectronic
device surface. For example, preferably less than 5 wt. % of the
SAM component polymerizes at the microelectronic device surface,
more preferably less than 2 wt. %, even more preferably less than 1
wt. %, and most preferably less than 0.1 wt. % of the SAM component
polymerizes at the microelectronic device surface.
[0046] In general, the specific proportions and amounts of at least
one solvent, at least one catalyst, at least one SAM component, and
optionally at least one surfactant, in relation to each other, may
be suitably varied to provide the desired cleaning and passivating
action of the liquid SAM-containing composition for the bulk and
hardened photoresist to be removed from the microelectronic device.
Such specific proportions and amounts are readily determinable by
simple experiment within the skill of the art without undue effort.
Most preferably, the SAM-containing component(s) and the
catalyst(s) are present in an amount effective to remove bulk and
hardened photoresist material from a microelectronic device having
said material thereon.
[0047] It is to be understood that the phrase "removing bulk and
hardened photoresist material from a microelectronic device" is not
meant to be limiting in any way and includes the removal of bulk
and hardened photoresist material from any substrate that will
eventually become a microelectronic device.
[0048] It is also contemplated herein that the liquid
SAM-containing composition of the present invention may be used to
remove hardened photoresist, e.g., BEOL hardened photoresist,
bottom anti-reflective coating (BARC) material, post-CMP residue,
BARC residue and/or post-ash/post-etch photoresist, while
simultaneously passivating the underlying silicon-containing
layer(s) or any other hydrophilic surface having
hydroxyl-terminated groups in need of passivation. In addition, the
liquid SAM-containing compositions of the present invention may be
used to remove contaminating materials from photomask materials for
re-use thereof.
[0049] The liquid SAM-containing compositions of the invention may
optionally be formulated with additional components to further
enhance the passivation and removal capability of the composition,
or to otherwise improve the character of the composition, i.e.,
provide metal passivation. Accordingly, the composition may be
formulated with stabilizers, complexing agents, passivators, e.g.,
Cu passivating agents, and/or corrosion inhibitors.
[0050] The liquid SAM-containing compositions of the invention are
easily formulated by the mixture of solvent(s), catalyst(s), SAM
component(s), and optional surfactant(s) with gentle agitation. The
solvent(s), catalyst(s), SAM component(s), and optional
surfactant(s) may be readily formulated as single-package
formulations or multi-part formulations that are mixed at the point
of use. The individual parts of the multi-part formulation may be
mixed at the tool or in a storage tank upstream of the tool. The
concentrations of the single-package formulation or the individual
parts of the multi-part formulations may be widely varied in
specific multiples, i.e., more dilute or more concentrated, in the
broad practice of the invention, and it will be appreciated that
the liquid SAM-containing compositions of the invention can
variously and alternatively comprise, consist or consist
essentially of any combination of ingredients consistent with the
disclosure herein.
[0051] Accordingly, another aspect of the invention relates to a
kit including, in one or more containers, one or more components
adapted to form the compositions of the invention. Preferably, the
kit includes, in one or more containers, at least one solvent, at
least one SAM component, and optionally at least one surfactant for
combining with the at least one catalyst at the fab. According to
another embodiment, the kit includes, in one or more containers, at
least one SAM component, and optionally at least one surfactant for
combining with the at least one solvent and the at least one
catalyst at the fab. In yet another embodiment, the kit includes in
one container at least one SAM component in solvent and in another
container at least one catalyst in solvent for combining at the
fab. For example, the containers of the kit may be NOWPak.RTM.
containers (Advanced Technology Materials, Inc., Danbury, Conn.,
USA).
[0052] In yet another embodiment, the invention relates to a liquid
SAM-containing composition useful in removing bulk and hardened
photoresist from a microelectronic device, wherein the liquid
SAM-containing composition includes at least one solvent, at least
one catalyst, at least one SAM component, optionally at least one
surfactant, and photoresist residue material, wherein the
photoresist is bulk and/or hardened photoresist. Importantly, the
residue material may be dissolved and/or suspended in the liquid
SAM-containing composition of the invention. In still another
embodiment, the photoresist residue material includes an ion
selected from the group consisting of boron ions, arsenic ions,
phosphorus ions, indium ions, and antimony ions.
[0053] In yet another aspect, the invention relates to dense
SAM-containing compositions including dense fluids, e.g.,
supercritical fluids (SCF), as the primary solvent system. Because
of its readily manufactured character and its lack of toxicity and
negligible environmental effects, supercritical carbon dioxide
(SCCO.sub.2) is the preferred SCF. SCCO.sub.2 is an attractive
reagent for removal of microelectronic device process contaminants,
since SCCO.sub.2 has the characteristics of both a liquid and a
gas. Like a gas, it diffuses rapidly, has low viscosity, near-zero
surface tension, and penetrates easily into deep trenches and vias.
Like a liquid, it has bulk flow capability as a "wash" medium.
SCCO.sub.2 has a density comparable to organic solvents and also
has the advantage of being recyclable, thus minimizing waste
storage and disposal requirements.
[0054] The dense SAM-containing composition according to one
embodiment comprises SCCO.sub.2 and the liquid SAM-containing
composition, i.e., a SAM-containing concentrate, in the following
ranges, based on the total weight of the composition:
TABLE-US-00003 component of % by weight SCCO.sub.2 about 95.0% to
about 99.99% liquid SAM-containing composition about 0.01% to about
10.0%
where the liquid SAM-containing composition comprises about 75.0%
to about 90.0% co-solvent, about 0.01% to about 10.0% SAM
component, about 0.01% to about 10.0% catalyst and optionally 0 to
about 10.0% surfactant, wherein the co-solvent(s),
SAM-component(s), catalyst(s) and optional surfactant(s)
contemplated include the aforementioned species.
[0055] In one aspect, the range of mole ratios of liquid
SAM-containing composition relative to SCCO.sub.2 in the dense
SAM-containing composition is about 1:200 to about 1:4, more
preferably about 1:100 to about 1:6.
[0056] In the broad practice of the invention, the dense
SAM-containing composition may comprise, consist of, or consist
essentially of SCCO.sub.2 and the liquid SAM-containing
composition, i.e., at least one additional solvent, at least one
catalyst, at least one SAM component, and optionally at least one
surfactant. In general, the specific proportions and amounts of
SCCO.sub.2 and liquid SAM-containing composition, in relation to
each other, may be suitably varied to provide the desired removal
action of the dense SAM-containing composition for the bulk and
hardened photoresist and/or processing equipment, as readily
determinable within the skill of the art without undue effort.
Importantly, the liquid SAM-containing composition may be at least
partially dissolved and/or suspended within the dense fluid of the
dense SAM-containing composition.
[0057] In yet another embodiment, the invention relates to a dense
SAM-containing composition useful in removing bulk and hardened
photoresist from a microelectronic device, wherein the dense
SAM-containing composition includes SCCO.sub.2, at least one
solvent, at least one catalyst, at least one SAM component,
optionally at least one surfactant, and photoresist residue
material, wherein the photoresist is bulk and/or hardened
photoresist. Importantly, the residue material may be dissolved
and/or suspended in the dense SAM-containing composition of the
invention. In still another embodiment, the photoresist residue
material includes an ion selected from the group consisting of
boron ions, arsenic ions, phosphorus ions, indium ions, and
antimony ions.
[0058] It is also contemplated herein that the dense SAM-containing
composition of the present invention may be used to remove hardened
photoresist, e.g., BEOL hardened photoresist, bottom
anti-reflective coating (BARC) material, post-CMP residue, BARC
residue and/or post-ash/post-etch photoresist, while simultaneously
passivating the underlying silicon-containing layer(s) or any other
hydrophilic surface having hydroxyl-terminated groups in need of
passivation. In addition, the dense SAM-containing compositions of
the present invention may be used to remove contaminating materials
from photomask materials for re-use thereof.
[0059] In yet another aspect, the invention relates to methods of
removal of bulk and hardened photoresist from a microelectronic
device using the SAM-containing compositions described herein. For
example, trench and via structures on the patterned devices may be
cleaned while maintaining the structural integrity of the
underlying silicon-containing layers using SAM passivation. It
should be appreciated by one skilled in the art that the
SAM-containing compositions may be used in a one-step or multi-step
removal process.
[0060] The SAM-containing compositions of the present invention
overcome the disadvantages of the prior art removal techniques by
reversibly passivating the underlying silicon-containing layer(s),
while simultaneously removing the bulk and hardened photoresist
deposited thereon.
[0061] The liquid SAM-containing compositions of the present
invention are readily formulated by simple mixing of ingredients,
e.g., in a mixing vessel or the cleaning vessel under gentle
agitation. The dense SAM-containing compositions are readily
formulated by static or dynamic mixing at the appropriate
temperature and pressure.
[0062] In passivation and removal application, the liquid
SAM-containing composition is applied in any suitable manner to the
microelectronic device having photoresist material thereon, e.g.,
by spraying the composition on the surface of the device, by
dipping (in a volume of the composition) of the device including
the photoresist material, by contacting the device with another
material, e.g., a pad, or fibrous sorbent applicator element, that
is saturated with the composition, by contacting the device
including the photoresist material with a circulating composition,
or by any other suitable means, manner or technique, by which the
liquid SAM-containing composition is brought into contact with the
photoresist material on the microelectronic device. The passivation
and removal application may be static or dynamic, as readily
determined by one skilled in the art.
[0063] In use of the compositions of the invention for removing
photoresist material from microelectronic device surfaces having
same thereon, the liquid SAM-containing composition typically is
contacted with the device surface for a time of from about 1 to
about 60 minutes, the preferred time being dependent on the dopant
ion dose and the implant energy employed during ion implantation,
wherein the higher the dopant ion dose and/or implant energy, the
longer the contacting time required. Preferably, temperature is in
a range of from about 20.degree. C. to about 80.degree. C.,
preferably about 30.degree. C. to about 80.degree. C., most
preferably about 70.degree. C. Such contacting times and
temperatures are illustrative, and any other suitable time and
temperature conditions may be employed that are efficacious to at
least partially remove the photoresist material from the device
surface, within the broad practice of the invention. As defined
herein, "at least partial removal" corresponds to at least 90%
removal of bulk and hardened photoresist, preferably at least 95%
removal. Most preferably, at least 99% of said bulk and hardened
photoresist material is removed using the compositions of the
present invention.
[0064] Following the achievement of the desired passivation and
cleaning action, the microelectronic device may be thoroughly
rinsed with copious amounts of ethanol and/or THF to remove any
residual chemical additives.
[0065] The SAM-containing compositions of the invention selectively
remove 100% of highly doped (with 2.times.10.sup.15 As ions
cm.sup.-2) photoresist (500-700 nm thick) having a hardened,
cross-linked carbonized crust ranging from 30-70 nm in thickness.
Importantly, the hardened crust is removed without substantially
over-etching the underlying silicon-containing layer(s).
[0066] For passivation and cleaning applications using the dense
SAM-containing compositions, the microelectronic device surface
having the photoresist thereon is contacted with the dense
SAM-containing composition, at suitable elevated pressures, e.g.,
in a pressurized contacting chamber to which the dense
SAM-containing composition is supplied at suitable volumetric rate
and amount to effect the desired contacting operation, for at least
partial removal of the photoresist from the microelectronic device
surface. The chamber may be a batch or single wafer chamber, for
continuous, pulsed or static cleaning. The passivation and removal
of the hardened photoresist by the dense SAM-containing composition
may be enhanced by use of elevated temperature and/or pressure
conditions during contacting of the photoresist with the dense
SAM-containing composition.
[0067] The appropriate dense SAM-containing composition may be
employed to contact a microelectronic device surface having
photoresist thereon at a pressure in a range of from about 1,500 to
about 4,500 psi for sufficient time to effect the desired removal
of the photoresist, e.g., for a contacting time in a range of from
about 5 minutes to about 30 minutes and a temperature of from about
40.degree. C. to about 75.degree. C., although greater or lesser
contacting durations and temperatures may be advantageously
employed in the broad practice of the present invention.
[0068] The removal process using the dense SAM-containing
composition may include a static soak, a dynamic cleaning mode, or
sequential processing steps including dynamic flow of the dense
SAM-containing composition over the microelectronic device surface,
followed by a static soak of the device in the dense SAM-containing
composition, with the respective dynamic flow and static soak steps
being carried out alternatingly and repetitively, in a cycle of
such alternating steps.
[0069] A "dynamic" contacting mode involves continuous flow of the
composition over the device surface, to maximize the mass transfer
gradient and effect complete removal of the resist from the
surface. A "static soak" contacting mode involves contacting the
device surface with a static volume of the composition, and
maintaining contact therewith for a continued (soaking) period of
time.
[0070] Following the contacting of the dense SAM-containing
composition to the microelectronic device surface, the device
thereafter preferably is washed with rinsing solution, for example,
aliquots of SCF/co-solvent solution, e.g., SCCO.sub.2/methanol
(80%/20%) solution, and pure SCF, to remove any residual
precipitated chemical additives from the region of the device
surface in which resist removal has been effected.
[0071] It will be appreciated that specific contacting conditions
for the liquid SAM-containing and the dense SAM-containing
compositions of the invention are readily determinable within the
skill of the art, based on the disclosure herein, and that the
specific proportions of ingredients and concentrations of
ingredients in the compositions of the invention may be widely
varied while achieving desired passivation of the underlying
silicon-containing layer(s) and removal of the hardened photoresist
material on the microelectronic device surface.
[0072] Another aspect of the invention relates to methods of
removal of bulk and hardened photoresist from a microelectronic
device, said method including passivation of the underlying
silicon-containing layer(s) on the microelectronic device surface
using non-halide containing SAM component, e.g.,
hexamethyldisilazane (HMDS), and removing the bulk and hardened
photoresist from the microelectronic device using an
etchant-containing removal composition. Suitable etchant-containing
removal compositions include without limitation, hydrogen fluoride
(HF), ammonium fluoride (NH.sub.4F), alkyl hydrogen fluoride
(NRH.sub.3F), dialkylammonium hydrogen fluoride (NR.sub.2H.sub.2F),
trialkylammonium hydrogen fluoride (NR.sub.3HF), trialkylammonium
trihydrogen fluoride (NR.sub.3(3 HF)), tetraallcylammonium fluoride
(NR.sub.4F), pyridine-HF complex, pyridine/HCl complex,
pyridine/HBr complex, triethylamine/HF complex, triethylamine/HCl
complex, monoethanolamine/HF complex, triethanolamine/HF complex,
triethylamine/formic acid complex, and xenon difluoride
(XeF.sub.2), wherein each R in the aforementioned R-substituted
species is independently selected from C.sub.1-C.sub.8 alkyl and
C.sub.6-C.sub.10 aryl. Additional species are disclosed in
co-pending U.S. Provisional Patent Application No. 60/672,157,
filed Apr. 15, 2005 in the name of Pamela M. Visintin et al. for
"Dense Fluid Formulations for Cleaning Ion-Implanted Photoresist
Layers from Microelectronic Devices," which is incorporated herein
by reference in its entirety.
[0073] In yet another aspect, the invention relates to a method of
removing bulk and hardened photoresist material from a
microelectronic device having said photoresist material thereon,
said method comprising contacting the microelectronic device with a
SAM-containing composition for sufficient time to at least
partially remove said photoresist material from the microelectronic
device, with the provision that the SAM-containing composition is
devoid of an etchant component selected from the group consisting
of hydrogen fluoride, ammonium fluoride, ammonium bifluorides and
other well-known fluoride etchant species.
[0074] Regardless of the method used to remove the hardened
photoresist from the microelectronic device, a further aspect of
the invention includes the removal of the SAM passivating layer
from the surface of the microelectronic device subsequent to the
removal of the photoresist material therefrom, referred to herein
as "depassivation."
[0075] When carbon contamination due to the passivating alkyl
groups on the wafer surface is unacceptable (approximately 3 to 10
.ANG. monolayer of methyl groups when Cl.sub.3SiMe is the SAM
used), the SAM may be removed using strong acids such as
H.sub.2SO.sub.4, however, this may cause unwanted oxidation of the
underlying silicon-containing layer(s). Thus, dilute inorganic
acids including halide ions, such as HCl and HF, are preferred
under optimized process conditions. The halide ions will readily
attack a passivating Si--O--Si bond at the SAM-device surface
interface and thus "depassivate" the device surface. However,
special care should be taken to minimize over-etching of the
silicon-containing layer(s) on the device surface.
[0076] The inventors have previously shown that anhydrous solutions
of HF/Pyridine (1:1 mole ratio) in DMSO are known to etch thermal
oxide, TEOS, silicon nitride, and polysilicon at rates less than
<0.1 .ANG. min.sup.-1. Thus, the depassivating solution may
include about 0.01 wt % to about 2 wt. % dilute inorganic
acid/amine complex and/or inorganic acid in a solvent to
depassivate the device surface with only slight fluorination and
over-etching of the underlying silicon-containing layers. Dilute
inorganic acid/amine complexes and inorganic acids contemplated
herein include pyridine/HF complex, pyridine/HCl complex,
pyridine/HBr complex, triethylamine/HF complex, triethylamine/HCl
complex, fluorosilicic acid, hydrofluoric acid, tetrafluoroboric
acid, and triethylamine/formic acid complex, and combinations
thereof with peroxides, concentrated HCl, ammonium hydroxide, and
mixtures thereof. These compositions may be aqueous-based,
solvent-based, or combinations thereof. For example, solvents
contemplated herein for the depassivating solution include, but are
not limited to, water, DMSO, methanol, ethyl acetate, any of the
other aforementioned solvents, and combinations thereof. It is to
be understood that following depassivation, the depassivating
composition will include some amount of SAM compounds.
[0077] Yet another aspect of the invention relates to the improved
microelectronic devices made according to the methods of the
invention and to products containing such microelectronic
devices.
[0078] A still further aspect of the invention relates to methods
of manufacturing an article comprising a microelectronic device,
said method comprising contacting the microelectronic device with a
SAM-containing composition for sufficient time to at least
partially remove bulk and hardened photoresist material from the
microelectronic device having said photoresist material thereon,
and incorporating said microelectronic device into said article,
wherein the SAM-containing composition includes at least one
solvent, at least one catalyst, at least one SAM component, and
optionally at least one surfactant. Alternatively, the
SAM-containing composition may further include a dense fluid.
[0079] The features and advantages of the invention are more fully
shown by the illustrative example discussed below.
EXAMPLE 1
[0080] Atomic Force Microscopy (AFM) and surface energy
measurements were performed before and after contact of a sample
device surface with the SAM-containing compositions of the
invention to determine the extent of removal of hardened
photoresist as well as monolayer formation on the surface of said
device. The sample device surfaces included wafers consisting of
(from top to bottom) an ion-implanted photoresist layer
(2.times.10.sup.15 As ions cm.sup.-2; 10 keV implant energy), a
bulk photoresist layer, a silicon-containing gate oxide layer, and
a silicon substrate. The samples were processed for varying times
and at varying temperatures using varying SAM functionalities, and
the contact angles measured. The results are tabulated in Tables
1-3 hereinbelow. TABLE-US-00004 TABLE 1 Processing as a function of
time using a SAM-containing composition including 1 mmol
Cl.sub.3SiMe and 2 mmol Et.sub.3N in 10 mL of toluene, and a
contacting temperature of 70.degree. C. Time Contact Angle
(.degree.) 0 (control) 35 .+-. 3 10 min 77 .+-. 2 30 min 79 .+-. 1
1 hour 80 .+-. 1 15 hours 95 .+-. 4
[0081] TABLE-US-00005 TABLE 2 Processing as a function of
temperature using a SAM-containing composition including 1 mmol
Cl.sub.3SiMe and 2 mmol Et.sub.3N in 10 mL of toluene, and a
contacting time of 30 min. Temperature/.degree. C. Contact Angle
(.degree.) control 35 .+-. 3 50.degree. C. 75 .+-. 2 60.degree. C.
79 .+-. 2 70.degree. C. 79 .+-. 1
[0082] TABLE-US-00006 TABLE 3 Processing as a function of SAM
functionalities using a SAM-containing composition including 1 mmol
of the listed SAM and 2 mmol Et.sub.3N in 10 mL of toluene, at a
contacting temperature of 70.degree. C. for a contacting time of 30
min. SAM Contact Angle (.degree.) Cl.sub.3SiMe 79 .+-. 1
Cl.sub.2Si(Me).sub.2 86 .+-. 1 ClSi(Me).sub.3 97 .+-. 1 Cl.sub.3SiH
87 .+-. 4
[0083] Passivation of the underlying silicon-containing layer is
evidenced by an increase in the contact angle following application
of the SAM-containing composition with the device surface. It can
be seen in Table 1 that a process time of less than 10 minutes is
needed to transform the hydroxyl-terminated hydrophilic device
surface, having a contact angle of 35 degrees, to a
methyl-terminated hydrophobic surface, having a contact angle of 77
degrees.
[0084] The corresponding AFM images illustrated in FIGS. 1A-1D, at
contacting times equal to 10 min, 30 min, 1 hour and 15 hours,
respectively, clearly show that as time increased (while
maintaining all other process parameters constant), small islands
form on the silicon-containing surface due to polymerization (or
cross-linking) of the multi-substituted chlorosilane. As process
time is increased, the islands gradually coalesce, or agglomerate,
and at 15 hours show evidence of bulk polymerization on the
surface.
[0085] The preliminary temperature studies were performed to
determine the most effective temperature for surface passivation
and cleaning efficiency. With regards to cleaning efficiency, four
different microelectronic device layers were considered: bulk
blanketed photoresist; the 30-45 nm ion-implanted crust on the bulk
blanketed photoresist; bulk patterned photoresist; and the
ion-implanted crust on the bulk patterned photoresist. Comparing
the results reported in Table 2 (the contact angles) with the
percent removal efficiency illustrated in FIG. 2, it can be seen
that temperatures greater than 60.degree. C. provide the greatest
amount of passivation as well as almost 100% removal of
photoresist. Accordingly, all subsequent experiments as a function
of time and SAM functionality were performed at 70.degree. C.
[0086] The evidence of cross-linking is better shown in FIGS.
3A-3C, which illustrate the variation of cross-linking as a
function of SAM functionality, specifically the number of chloride
leaving groups, at temperature of 70.degree. C. and time of 30 min.
It can be seen that with ClSiMe.sub.3 (FIG. 3A), the ability of the
SAM to cross-link does not exist, and a smooth monolayer (rms=0.415
nm; control rms=0.131 nm) is formed on the surface. However, with
Cl.sub.2SiMe.sub.2 (FIG. 3B) and Cl.sub.3SiMe (FIG. 3C),
cross-linking occurs as evidenced by the island formation described
hereinabove, which as a result, leads to rougher film surfaces
(rms=0.465 and 1.573 nm for the di- and tri-chlorosilanes,
respectively). The formation of islands is indicative of the
necessity for more aggressive depassivation techniques (e.g., more
concentrated compositions, greater contact time, etc.).
EXAMPLE 2
[0087] FIGS. 4A-4C show the optical (FIG. 4A) and scanning electron
microscopic (SEM) images of sample device surfaces including a
layer of densely patterned, highly doped (2.times.10.sup.15 As ions
cm.sup.2; 10 keV implant energy) photoresist consisting of a region
of parallel lines. The 30 nm thick hardened crust can be clearly
seen in the 90 degree angle view image (FIG. 4C). The cleaning
efficiency of the crust as a function of chloride substitution on
the SAM component is illustrated in FIG. 5A (ClSiMe.sub.3), FIG. 5B
(Cl.sub.2SiMe.sub.2), and FIG. 5C (Cl.sub.3SiMe). The optical
microscope images in FIGS. 5A-5C illustrate that as the number of
chloride leaving groups on the SAM component increases, the amount
of hardened photoresist removed also increases. In fact, greater
than 90% removal of the four different microelectronic device
layers is achievable using the Cl.sub.3SiMe-containing composition
(see FIG. 6). It is thought that the increase in crust removal is
the result of an increase in HCl generated when the SAM-containing
composition is applied to the device surface.
[0088] An additional experiment was performed whereby a non-halide
containing SAM-containing composition was contacted with the sample
device surface including densely patterned, highly doped
photoresist and underlying silicon-containing layer(s). No hardened
photoresist was removed, even though the sample was passivated as
evidenced by the contact angle of 63.degree.. Therefore, our
results show that some amount of leaving group, e.g., chloride, is
necessary for hardened photoresist removal.
EXAMPLE 3
[0089] A further aspect of the invention includes the removal of
the passivating layer from the surface of the microelectronic
device, or "depassivation." FIG. 7A is an optical microscope image
of a densely patterned device surface having a contact angle of
36.degree. and an rms=0.15 nm. FIG. 7B is an optical image of the
device surface of FIG. 7A following application at 70.degree. C.
for 30 min of a SAM-containing composition including Cl.sub.3SiMe.
The contact angle of the passivated surface was determined to be
79.degree. (with a rms=1.10 nm), evidencing passivation of the
silicon-containing surface. It can be seen that at least 90% of the
hardened photoresist was removed. FIG. 7C is an optical image of
the device surface of FIG. 7B following depassivation at 50.degree.
C. for 2 min using NEt.sub.3:HF (1:3 mole ratio) in DMSO
composition. The contact angle of the depassivated surface was
determined to be 35.degree. (with a rms=0.25 nm). Once the contact
angle of the surface matches that of the surface prior to contact
with the SAM-containing composition, the depassivation process is
essentially complete.
[0090] It is noted that the depassivation process should be
optimized in order to eliminate fluorination and/or over-etching of
the underlying silicon-containing layer(s). For example,
depassivation may be performed in 30 second intervals for SAM
removal from thermal oxide-containing device structures and 20
second intervals for SAM removal from TEOS-based device
structures.
[0091] FIGS. 8A-8E provide another illustration of the passivation
and cleaning results, as well as depassivation following removal of
the hardened photoresist. FIG. 8A is a SEM of a device surface
including a densely patterned, highly doped (2.times.10.sup.15 As
ions cm.sup.-2; 10 keV implant energy) photoresist layer prior to
processing. FIG. 8B is a SEM of the densely patterned surface of
FIG. 8A following application at 70.degree. C. for 30 min of a
SAM-containing composition including Cl.sub.3SiMe, illustrating the
successful and efficient removal (and passivation) of the hardened
photoresist. FIGS. 8C and 8D are SEMs of the device surface of FIG.
8B following depassivation at 50.degree. C. for 2 min using
NEt.sub.3:HF (1:3 mole ratio) in DMSO composition. The SEM image in
FIGS. 8C and 8D do not show any evidence of substantial
over-etching of the underlying silicon-containing layers during the
depassivation process (compare with the over-etched sample in FIG.
8E).
[0092] The improved SAM-containing compositions taught herein
effectively remove bulk and hardened photoresist in a one-step or
multi-step process, without the need for a plasma etch step and
without substantially over-etching the underlying
silicon-containing layer(s).
[0093] Accordingly, while the invention has been described herein
in reference to specific aspects, features and illustrative
embodiments of the invention, it will be appreciated that the
utility of the invention is not thus limited, but rather extends to
and encompasses numerous other aspects, features and embodiments.
Accordingly, the claims hereafter set forth are intended to be
correspondingly broadly construed, as including all such aspects,
features and embodiments, within their spirit and scope.
* * * * *