U.S. patent application number 13/978825 was filed with the patent office on 2014-10-30 for formulations for the removal of particles generated by cerium-containing solutions.
This patent application is currently assigned to ADVANCED TECHNOLOGY MATERIALS, INC.. The applicant listed for this patent is Jeffrey A. Barnes, Emanuel I. Cooper. Invention is credited to Jeffrey A. Barnes, Emanuel I. Cooper.
Application Number | 20140318584 13/978825 |
Document ID | / |
Family ID | 46507664 |
Filed Date | 2014-10-30 |
United States Patent
Application |
20140318584 |
Kind Code |
A1 |
Cooper; Emanuel I. ; et
al. |
October 30, 2014 |
FORMULATIONS FOR THE REMOVAL OF PARTICLES GENERATED BY
CERIUM-CONTAINING SOLUTIONS
Abstract
Compositions and methods for removing lanthanoid-containing
solids and/or species from the surface of a microelectronic device
or microelectronic device fabrication hardware. Preferably, the
lanthanoid-containing solids and/or species comprise cerium. The
composition is preferably substantially devoid of fluoride
ions.
Inventors: |
Cooper; Emanuel I.;
(Scarsdale, NY) ; Barnes; Jeffrey A.; (Bethlehem,
CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cooper; Emanuel I.
Barnes; Jeffrey A. |
Scarsdale
Bethlehem |
NY
CT |
US
US |
|
|
Assignee: |
ADVANCED TECHNOLOGY MATERIALS,
INC.
Danbury
CT
|
Family ID: |
46507664 |
Appl. No.: |
13/978825 |
Filed: |
January 12, 2012 |
PCT Filed: |
January 12, 2012 |
PCT NO: |
PCT/US12/21069 |
371 Date: |
September 23, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61432370 |
Jan 13, 2011 |
|
|
|
Current U.S.
Class: |
134/42 ; 510/175;
510/176 |
Current CPC
Class: |
H01L 21/31133 20130101;
H01L 21/02076 20130101; H01L 21/02057 20130101 |
Class at
Publication: |
134/42 ; 510/175;
510/176 |
International
Class: |
H01L 21/02 20060101
H01L021/02 |
Claims
1. A method of removing lanthanoid-containing solids and/or species
from the surface of a microelectronic device or microfabrication
hardware, said method comprising contacting the surface with a
composition that substantially dissolves the lanthanoid-containing
solids and/or species present on the surface.
2. The method of claim 1, wherein the lanthanoid-containing solids
are particulate matter present on the surface.
3. The method of claim 2, wherein the selectivity of the
composition for the lanthanoid-containing solids and/or species
relative to the surface is at least about 100:1.
4. The method of claim 1, wherein the lanthanoid-containing species
are ionic or molecular in nature and are adsorbed onto the surface
of the microelectronic device or microfabrication hardware.
5. The method of claim 1, wherein the lanthanoid-containing solids
and/or species comprises at least one species selected from the
group consisting of lanthanum, cerium, praseodymium, neodymium,
promethium, samarium, europium, gadolinium, terbium, dysprosium,
holmium, erbium, thulium, ytterbium, and lutetium.
6. The method of claim 1 The method of any of the preceding claims,
wherein the lanthanoid-containing solids and/or species comprises
cerium.
7. The method of claim 6, wherein the lanthanoid-containing solids
and/or species comprise Ce(IV).
8. The method of claim 1, wherein temperature is in a range from
about room temperature to about 100.degree. C. for time in a range
from about 10 sec to about 60 minutes.
9. (canceled)
10. (canceled)
11. The method of claim 1, said method further comprising, prior to
contacting the surface with the composition that substantially
dissolves the lanthanoid-containing solids and/or species,
contacting the surface of the microelectronic device with a resist
removal composition comprising at least one salt or coordination
complex of a lanthanoid element to remove resist from said
surface.
12. The method of claim 11, wherein the resist removal composition
comprises cerium.
13. The method of claim 11, wherein the resist removal composition
comprises cerium ammonium nitrate.
14. The method of claim 1, wherein the composition comprises at
least one acid, at least one reducing agent, and water, wherein the
composition is substantially devoid of fluoride ions.
15. The method of claim 1, wherein the pH of the composition is in
a range from about 0 to about 4.
16. The method of claim 14, wherein the at least one reducing agent
comprises hydrogen peroxide, ascorbic acid, borane-pyridine,
borane-morpholine, hydroxylamine sulfate, hydroxylamine
hydrochloride, ammonium nitrite, ammonium sulfite, ammonium
hydrogen sulfite, hydrazine sulfate, hydrazine hydrochloride,
ammonium hydrogen sulfide, diethyl malonate, hydroquinone, ammonium
metabisulfite, polyphenon 60, glucose, ammonium citrate, hydrogen,
formic acid, oxalic acid, acetaldehyde, hydrogen iodide, ammonium
phosphite, ammonium hydrogen phosphite, hypophosphorous acid, and
combinations thereof.
17. The method of claim 14, wherein the at least one reducing agent
comprises ascorbic acid.
18. The method of claim 14, wherein the at least one acid comprises
at least one strong acid or at least one weak acid.
19. The method of claim 18, wherein the at least one strong acid
comprises a species selected from the group consisting of nitric
acid, sulfuric acid, perchloric acid, hydrochloric acid,
hydrobromic acid, hydroiodic acid, methanesulfonic acid, and
combinations thereof.
20. The method of claim 18, wherein the at least one strong acid
comprises sulfuric acid.
21. The method of claim 18, wherein the composition further
comprises the salt of the at least one strong acid.
22. (canceled)
23. The method of claim 18, wherein the at least one weak acid
comprises a species selected from the group consisting of nitrous
acid, phosphorous acid, hydrogen bisulfate, hydrogen selenite,
phosphoric acid, cyanic acid, formic acid, glyceric acid, glycolic
acid, glyoxylic acid, lactic acid, pyruvic acid, mandelic acid,
succinic acid, malonic acid, and combinations thereof.
Description
FIELD
[0001] The present invention relates to compositions and methods
for removing lanthanoid-containing solids and/or species from the
surface of a microelectronic device or microelectronic device
fabrication hardware. Preferably, the compositions and methods
remove cerium-containing solids and/or species from surfaces.
DESCRIPTION OF THE RELATED ART
[0002] Resist, including photoresist, is a radiation sensitive
(e.g., light radiation sensitive) material used to form a patterned
layer on a substrate (e.g., a semiconductor wafer) during
semiconductor device fabrication. After exposing a portion of a
resist coated substrate to radiation, either the exposed portion of
the resist (for positive resist), or the unexposed portion of the
resist (for negative resist) is removed to reveal the underlying
surface of the substrate, leaving the rest of the surface of the
substrate coated and protected by resist. Resist may be more
generally referred to as a masking material. Other fabrication
processes such as ion-implanting, etching, or depositing may be
performed on the uncovered surface of the substrate and the
remaining resist. After performing the other fabrication processes,
the remaining resist is removed in a strip operation.
[0003] In ion-implantation, dopant ions (e.g., ions of boron, boron
difluoride, arsenic, indium, gallium, phosphorous, germanium,
antimony, xenon or bismuth) are accelerated toward a substrate to
be implanted. The ions are implanted in the exposed regions of the
substrate as well as in the remaining resist. Ion-implantation may
be used, for example, to form implanted regions in the substrate
such as the channel region and source and drain regions of
transistors. Ion-implantation may also be used to form lightly
doped drain and double diffused drain regions. However, ions
implanted in the resist may deplete hydrogen from the surface of
the resist causing the resist to form an outer layer or crust,
which may be a carbonized layer that is harder than the underlying
portion of the resist layer (i.e., the bulk portion of the resist
layer). The outer layer and the bulk portion have different thermal
expansion rates and react to stripping processes at different
rates. High dose ion-implanted resist may cause severe hardening or
crusting of the resist resulting in relatively large differences
between the outer layer and bulk portion in, for example,
differences in thermal expansion rates, solubilities and other
chemical and physical characteristics.
[0004] The present inventors previously discovered that a
composition comprising at least one salt or coordination complex of
the element cerium, e.g., ceric ammonium nitrate (CAN), can
effectively remove masking material, e.g., high dose ion-implanted
resist, from a substrate. Advantageously, this composition and
method operates at a lower acidity and temperature than the
compositions and methods known in the prior art and as such, causes
less damage to TiN and other metal gate materials present on the
substrate. Disadvantageously, the reduction of cerium (IV)
compounds and sometimes the dilution of the solution with water may
result in precipitation of hydrolyzed solids such as
Ce(NO.sub.3).sub.x(OH).sub.y, where x+y.ltoreq.4, especially at
elevated temperatures typically used for HDIS. In addition,
hydrolyzed cerium species may adsorb to films present on the
substrate being treated.
[0005] It is an object of the present invention to substantially
remove the hydrolyzed solids that may precipitate or adsorb on
surfaces during the use of lanthanoid-containing compositions.
SUMMARY OF THE INVENTION
[0006] The present invention relates to compositions and methods
for removing lanthanoid-containing solids and/or species from the
surface of a microelectronic device or microelectronic device
fabrication hardware. Preferably, the compositions and methods
remove cerium-containing solids and/or species from surfaces.
[0007] Other aspects, features and advantages of the invention will
be more fully apparent from the ensuing disclosure and appended
claims.
DETAILED DESCRIPTION, AND PREFERRED EMBODIMENTS THEREOF
[0008] The present invention relates to compositions and methods
for removing lanthanoid-containing solids and/or species from the
surface of a microelectronic device or microelectronic device
fabrication hardware. Preferably, the compositions and methods
remove cerium-containing solids and/or species from surfaces. The
composition is preferably substantially devoid of fluoride
ions.
[0009] In one aspect, a method of removing lanthanoid-containing
solids and/or species from the surface of a microelectronic device
or microfabrication hardware is described, said method comprising
contacting the surface with a composition that substantially
dissolves the lanthanoid-containing solids and/or species present
on the surface. Preferably, the composition comprises at least one
acid, at least one reducing agent, and water, wherein the
composition is substantially devoid of fluoride ions.
[0010] For ease of reference, "microelectronic device" corresponds
to semiconductor substrates, flat panel displays, phase change
memory devices, solar panels and other products including solar
cell devices, photovoltaics, and microelectromechanical systems
(MEMS), manufactured for use in microelectronic, integrated
circuit, energy collection, or computer chip applications. It is to
be understood that the terms "microelectronic device,"
"microelectronic substrate" and "microelectronic device structure"
are not meant to be limiting in any way and include any substrate
or structure that will eventually become a microelectronic device
or microelectronic assembly. The microelectronic device can be
patterned, blanketed, a control and/or a test device.
[0011] "Ion-implantation" is a process by which ions of a dopant
material can be implanted into target material, usually a solid.
The physical properties of an ion-implanted material are usually
different from the physical properties of the target material prior
to implantation. Ion-implantation is used in microelectronic device
fabrication, for example, in the fabrication of integrated circuits
and silicon semiconductor devices. The implanted ions may introduce
or cause a chemical change in the target due to the ions being a
different element than the target, and/or a structural change, in
that the target may be modified, damaged or even destroyed by
ion-implantation. By way of example only, elements that are
typically used for implanted species in semiconductor fabrication
include boron, boron difluoride, arsenic, indium, gallium,
germanium, bismuth, xenon, phosphorus and antimony. Boron is a
p-type dopant in silicon because it donates or causes a "hole"
(i.e., electron vacancy) in the silicon. Arsenic is an n-type
dopant in silicon because it donates or causes an extra electron in
the silicon. Dopants, such as boron and arsenic, implanted in
intrinsic silicon, may cause the intrinsic silicon to become
conductive as a semiconductor. One or more dopant materials may be
implanted into a target material. Ion-implantation is usually
characterized by dose and energy. The dose is the number of ions
that are implanted per area of target material. The energy is the
energy of the ions being implanted. More advanced microelectronic
device processing or fabrication technologies typically use higher
dose and/or higher energy than older technologies. In high dose
ion-implantation (HDII), the ion dose may be greater than about
5.times.10.sup.14 ions/cm.sup.2 and/or the average energy of the
ions, before the ions impact the target or substrate, may be from
about five thousand electron volts (KeV) to greater than 100
KeV.
[0012] "Resist" including photoresist (more generally, masking
material) is a radiation sensitive material that is used to form a
patterned coating on a surface, for example, the surface of a
substrate or target. Resists are used in the fabrication of
microelectronic devices, for example, integrated circuits and
silicon semiconductor devices. One use of resists in the
fabrication of semiconductor devices is as a mask for selective
ion-implantation of dopants into a semiconductor substrate. A layer
of resist is applied to the surface of the semiconductor substrate,
or to the surface of a layer on or within the substrate, such as an
insulator layer above a semiconductor layer. A portion of the
resist is exposed to the radiation, such portion of the resist
corresponding to either the area of the semiconductor to be
implanted (positive resist) or to the area of the semiconductor not
to be implanted (negative resist). The resist is then exposed to a
developer which assists in removing a portion of the resist so that
only the desired portion of the resist remains. Ion-implantation
occurs after the resist is patterned by exposure to the radiation
and developed by the developer. The remaining portion of the resist
blocks the implanted ions from reaching the microelectronic device,
or other material, below the resist. The ions blocked by the resist
are implanted into the resist instead of the underlying substrate.
The portions of the microelectronic device not covered by resist
are ion-implanted. Because of the relatively high dose and/or high
energy of the implanted ions blocked by the resist, the resist
forms a crust or hard shell on the outer portions or outer sides of
the resist where the ions impact and are absorbed. The resist
hardening may result from, or be referred to as, carbonization,
polymerizing or polymer cross-linking. The crust is known to be
difficult to remove during a resist stripping process (e.g., the
crust is insoluble in some known solvents used for stripping). The
thickness of the resist crust is dependent upon the dosage of the
implanted ions and the ion-implant energy. The resist material that
is inside or beneath the crust, that is, the portion of the resist
that is generally unaffected by the ions, is referred to as bulk
resist or bulk resist material.
[0013] "High dose ion-implantation strip" (HDIS) is the process of
stripping exposed resist that has received HDII. Some HDIS
processes may include dry processes, such as plasma processes and
vacuum processes. Characteristics of an HDIS process may include,
for example, strip rate, amount of residue, and loss of the exposed
and underlying layer, such as the substrate, silicon substrate or
layers above silicon. Residues are sometimes found on the substrate
surface after an HDIS. The residues may result from, for example,
sputtering during HDII, incomplete removal of the outer layer of
resist, and/or oxidation of implanted ions in the resist.
Optimally, after stripping and, optionally, rinsing, the surface
should be substantially residue free to ensure high yield and
eliminate the need for additional residue removal processing.
[0014] As defined herein, the "surface" comprises at least silicon,
a metal gate material, or both, for example, TiN comprised in a
metal gate of an field-effect transistor (FET) or TiN comprised in
a barrier between a semiconductor and a metal. Silicon is comprised
in silicon-on-insulator (SOI) wafers that may be used, for example,
as substrates or part of a substrate for electronic devices such as
FETs and integrated circuits. "Silicon" may be defined to include,
Si, polycrystalline Si, monocrystalline Si, and SiGe. Other forms
of "silicon" may include silicon-containing materials such as
silicon oxide, thermal oxide, SiOH and SiCOH.
[0015] As defined herein, "metal gate material" corresponds to
materials having a Fermi level corresponding to the mid-gap of the
semiconductor substrate such as Ti, Ta, W, Mo, Ru, Al, La, titanium
nitride, tantalum nitride, tantalum carbide, titanium carbide,
molybdenum nitride, tungsten nitride, ruthenium (IV) oxide,
tantalum silicon nitride, titanium silicon nitride, tantalum carbon
nitride, titanium carbon nitride, titanium aluminide, tantalum
aluminide, titanium aluminum nitride, tantalum aluminum nitride,
lanthanum oxide, or combinations thereof. It should be appreciated
that the compounds disclosed as metal gate materials may have
varying stoichiometries. Accordingly, titanium nitride will be
represented as TiN.sub.x herein, tantalum nitride will be
represented as TaN.sub.x herein, and so on.
[0016] As used herein, "about" is intended to correspond to .+-.5%
of the stated value.
[0017] "Substantially devoid" is defined herein as less than 2 wt.
%, preferably less than 1 wt. %, more preferably less than 0.5 wt.
%, even more preferably less than 0.1 wt. %, and most preferably 0
wt.%.
[0018] As used herein, "to remove" means that material is dissolved
or otherwise solubilized in the composition, preferably
dissolved.
[0019] As used herein, "post-CMP residue" corresponds to particles
from the polishing slurry, e.g., silica-containing particles,
chemicals present in the slurry, reaction by-products of the
polishing slurry, carbon-rich particles, polishing pad particles,
brush deloading particles, equipment materials of construction
particles, copper, copper oxides, copper-containing materials,
aluminum, aluminum oxides, aluminum-containing materials, organic
residues, and any other materials that are the by-products of the
CMP process.
[0020] As used herein, "post-etch residue" corresponds to material
remaining following gas-phase plasma etching processes, e.g., BEOL
dual damascene processing. The post-etch residue may be organic,
organometallic, organosilicic, or inorganic in nature, for example,
silicon-containing material, carbon-based organic material, and
etch gas residue such as oxygen and fluorine.
[0021] As defined herein, "post-ash residue," as used herein,
corresponds to material remaining following oxidative or reductive
plasma aching to remove hardened photoresist and/or bottom
anti-reflective coating (BARC) materials. The post-ash residue may
be organic, organometallic, organosilicic, or inorganic in
nature.
[0022] Compositions of the invention may be embodied in a wide
variety of specific formulations, as hereinafter more fully
described.
[0023] 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 0.001
weight percent, based on the total weight of the composition in
which such components are employed.
[0024] The present invention relates to a composition and method of
use wherein the composition can be used to safely remove hydrolyzed
lanthanoid-containing solids and species, e.g., hydrolyzed
cerium-containing solids and species, from a substrate having same
thereon. As previously discussed, the reduction of
lanthanoid-containing compounds and sometimes the dilution of the
solution with water may result in precipitation of hydrolyzed
solids such as Ce(NO.sub.3).sub.x(OH).sub.y, where x+y.ltoreq.4,
especially at elevated temperatures typically used for HDIS. In
addition, hydrolyzed lanthanoid-containing species, which are ionic
or molecular in nature, may adsorb to films present on the surface
being treated. Lanthanoid elements are generally known to be those
elements with atomic numbers 57 through 71, i.e., lanthanum,
cerium, praseodymium, neodymium, promethium, samarium, europium,
gadolinium, terbium, dysprosium, holmium, erbium, thulium,
ytterbium, and lutetium. Hereinafter, "lanthanoid-containing
solids" and "lanthanoid-containing species" correspond to solids
that comprise a lanthanoid element which precipitate on the surface
as a result of reduction of the lanthanoid element, dilution of the
composition comprising the lanthanoid element, or both, or
otherwise adsorb to the surface.
[0025] In a first aspect, a method of removing
lanthanoid-containing solids from the surface of a microelectronic
device is described, said method comprising contacting the surface
with a composition that substantially dissolves the
lanthanoid-containing solids relative to the surface. Typically,
the lanthanoid-containing solids will be present as particulate
matter. Accordingly, "substantial dissolution" corresponds to the
dissolution of at least 95% of the volume of the particle relative
to the particle prior to contact with the composition, more
preferably at least 98%, even more preferably at least 99%, and
most preferably at least 99.9% of the volume of the particle
relative to the particle prior to contact with the composition.
Preferably, the selectivity of the composition for the
lanthanoid-containing solids relative to the surface is at least
about 100:1 lanthanoid-containing solid relative to surface, more
preferably at least about 1000:1, even more preferably at least
about 10000:1, and most preferably at least about 100000:1.
Considered another way, the surface should not be substantially
removed (i.e., dissolve, erode, etc.) by the composition while the
lanthanoid-containing solids should be substantially removed.
Preferably, the lanthanoid-containing solid comprises cerium.
[0026] In a second aspect, a method of removing
lanthanoid-containing species from the surface of a microelectronic
device is described, said method comprising contacting the surface
with a composition that substantially removes the
lanthanoid-containing species from the surface, wherein the
lanthanoid-containing species are adsorbed at the surface prior to
contact of the surface with the composition. Preferably, the
surface is not substantially affected by the composition, meaning
that the surface does not undergo substantial dissolution or
erosion in the presence of the composition. As defined herein,
"adsorption" corresponds to the adhesion of the
lanthanoid-containing species at a surface and can be characterized
as physisorption (physical adsorption characterized by weak van der
Waals forces) or chemisorption (chemical adsorption driven by a
chemical reaction occurring at a surface). Preferably, the
lanthanoid-containing species comprises cerium.
[0027] In a third aspect, a method of removing
lanthanoid-containing species and/or solids from microfabrication
hardware is described, said method comprising contacting the
surface of the hardware with a composition that substantially
removes the lanthanoid-containing species and/or solids from the
surface. Typically, the lanthanoid-containing solids will be
present as particulate matter and the lanthanoid-containing species
are adsorbed at the surface. Microfabrication hardware includes,
but is not limited to, hardware used during photolithography that
is exposed to compositions comprising lanthanoids. The material
construction of the microfabrication hardware may be metal,
plastic, glass, porcelain, or a mineral. Preferably, the lanthanoid
comprises cerium and the lanthanoid-containing solid and/or species
comprise cerium.
[0028] The methods of the first, second and third aspects are
carried out at temperature in a range from about room temperature
to about 100.degree. C., preferably about room temperature to about
80.degree. C., and most preferably about room temperature to about
60.degree. C. It should be appreciated by the skilled artisan that
the time of removal varies depending on whether the removal is
performed in a single wafer tool or a multiple wafer tool or
lanthanoid-containing species and/or solid is removed from
hardware. For a single wafer tool, time is preferably in a range
from about 10 sec to about 10 minutes, preferably about 20 sec to
about 5 minutes, and for a multiple wafer tool or hardware, time is
preferably in a range from about 1 minute to about 1000 minutes.
Such contacting times and temperatures are illustrative, and any
other suitable time and temperature conditions may be employed that
are efficacious to remove cerium-containing solids and/or species
from a surface.
[0029] In removal application from a surface of a microelectronic
device, the composition is applied in any suitable manner to the
device, e.g., by spraying the composition on the surface of the
device, by dipping the device in a static or dynamic volume of the
composition, by contacting the device with another material, e.g.,
a pad, or fibrous sorbent applicator element, that has the
composition absorbed thereon, or by any other suitable means,
manner or technique by which the composition is brought into
contact with the surface having the cerium-containing solids and/or
species thereon. Further, batch or single wafer processing is
contemplated herein. In removal application from hardware, the
composition is applied in any suitable manner to the hardware,
e.g., by spraying the composition on the surface of the hardware,
by dipping the hardware in a static or dynamic volume of the
composition, by contacting the hardware with another material,
e.g., a pad, or fibrous sorbent applicator element, that has the
composition absorbed thereon, or by any other suitable means,
manner or technique by which the composition is brought into
contact with the hardware having the cerium-containing solids
and/or species thereon.
[0030] Following the achievement of the desired removal action, the
composition is readily removed from the surface of the device or
the hardware to which it has previously been applied, e.g., by
rinse, wash, or other removal step(s), as may be desired and
efficacious. For example, the device or hardware may be rinsed with
a rinse solution including deionized water and/or dried (e.g.,
spin-dry, N.sub.2, solvents (such as IPA) vapor-dry etc.).
[0031] In a fourth aspect, a composition to remove
lanthanoid-containing solids and/or species is described, said
composition including at least one acid and at least one reducing
agent. In one embodiment, the composition comprises, consists of or
consists essentially of at least one strong acid, at least one
reducing agent, optionally at least one salt of the at least one
strong acid, and water, with the proviso that the composition is
substantially devoid of fluoride ions and when the at least one
strong acid is nitric acid and the at least one reducing agent is
hydrogen peroxide, the composition is substantially devoid of (i)
boric acid and (ii) an organic acid having an active carboxylic
acid group such as tartaric acid, citric acid, lactic acid,
gluconic acid and edetic acid. In another embodiment, the
composition comprises, consists of or consists essentially of at
least one weak acid, at least one reducing agent, and water, with
the proviso that the composition is substantially devoid of
fluoride ions. Preferably, the composition does not substantially
remove metal gate material present on the substrate. The water is
preferably deionized. Preferably, the composition is used in the
methods of the first through third aspects described herein.
[0032] The pH of the composition of the fourth aspect is in a range
from about 0 to about 4, preferably about 1 to about 3.5. When
titanium nitride layers are present, preferably the pH of the
composition is greater than or equal to 2 and less than 4.
[0033] The at least one strong acid is selected from the group
consisting of nitric acid, sulfuric acid, perchloric acid,
hydrochloric acid, hydrobromic acid, hydroiodic acid,
methanesulfonic acid, and combinations thereof. Preferably, the at
least one strong acid comprises sulfuric acid, nitric acid, or a
combination of nitric and sulfuric acid, even more preferably
sulfuric acid. The amount of the at least one strong acid is
preferably in a range from about 0.1 wt % to about 15 wt %,
preferably about 0.1 wt % to about 5 wt %, and most preferably
about 0.5 wt % to about 2.5 wt %, based on the total weight of the
composition.
[0034] The at least one reducing agent includes, but is not limited
to, hydrogen peroxide, ascorbic acid, borane complexes such as
borane-pyridine or borane-morpholine, hydroxylamine sulfate,
hydroxylamine hydrochloride, ammonium nitrite, ammonium sulfite,
ammonium hydrogen sulfite, hydrazine sulfate, hydrazine
hydrochloride, ammonium hydrogen sulfide, diethyl malonate,
hydroquinone, ammonium metabisulfite, polyphenon 60, glucose,
ammonium citrate, hydrogen, formic acid, oxalic acid, acetaldehyde,
hydrogen iodide, ammonium phosphite, ammonium hydrogen phosphite,
hypophosphorous acid, and combinations thereof. The above mentioned
"ascorbic acid" refers to not only ascorbic acid itself
(reduced-form) but also dehydroascorbic acid (oxidized-form),
xyloascorbic acid, arabo-ascorbic acid, optical isomers of both the
L-isomer and D-isomer, and esters of ascorbic acid. Preferably, the
at least one reducing agent comprises ascorbic acid or hydrogen
peroxide, preferably ascorbic acid. The amount of the at least one
reducing agent is preferably in a range from about 0.1 wt % to
about 10 wt %, preferably about 0.1 wt % to about 5 wt %, and most
preferably about 0.1 wt % to about 2 wt %, based on the total
weight of the composition.
[0035] When present, the salt of the at least one strong acid
corresponds to a sodium, potassium, tetramethylammonium, or
preferably ammonium salt of the conjugate base of the at least one
strong acid. For example, if the strong acid comprises sulfuric
acid, the salt of the at least one strong acid can be sodium
sulfate, potassium sulfate, tetramethylammonium sulfate, ammonium
sulfate, or the like. When present, the amount of salt of the at
least one strong acid is preferably in a range from about 0.1 to
about 10 wt %, preferably about 0.5 to about 5 wt %, based on the
total weight of the composition.
[0036] Accordingly, the components of the composition comprising,
consisting of or consisting essentially of at least one strong
acid, at least one reducing agent, optionally at least one salt of
the at least one strong acid, and water, with the proviso that the
composition is substantially devoid of fluoride ions and when the
at least one strong acid is nitric acid and the at least one
reducing agent is hydrogen peroxide, the composition is
substantially devoid of (i) boric acid and (ii) an organic acid
having an active carboxylic acid group such as tartaric acid,
citric acid, lactic acid, gluconic acid and edetic acid, are
present in the following amounts:
TABLE-US-00001 more most component preferably preferably preferably
alternative strong about 0.1 about 0.1 about 0.5 about 0.5 acid(s)
to about to about to about to about 15 wt % 5 wt % 2.5 wt % 2.5 wt
% reducing about 0.1 about 0.1 about 0.1 about 0.1 agent(s) to
about to about to about to about 10 wt % 5 wt % 2 wt % 2 wt % salt
of 0 0 0 0.5 strong to about to about to about to about acid 10 wt
% 10 wt % 10 wt % 5 wt % water about 65 about 80 about 90.5 about
85.5 to about to about to about to about 99.8 wt % 99.8 wt % 98.9
wt % 99.4 wt %
[0037] For the purposes of the present disclosure, a "weak acid"
preferably has a pKa in a range from about 1.5 to about 4. Weak
acids include, but are not limited to, nitrous acid, phosphorous
acid, hydrogen bisulfate, hydrogen selenite, phosphoric acid,
cyanic acid, formic acid, glyceric acid, glycolic acid, glyoxylic
acid, lactic acid, pyruvic acid, mandelic acid, succinic acid,
malonic acid, and combinations thereof. Preferably, the at least
one weak acid comprises formic acid. The amount of the at least one
weak acid is preferably in a range from about 0.1 wt % to about 15
wt %, preferably about 0.1 wt % to about 5 wt %, and most
preferably about 1 wt % to about 5 wt %, based on the total weight
of the composition.
[0038] Accordingly, the components of the composition comprising,
consisting of or consisting essentially of at least one weak acid,
at least one reducing agent, and water, with the proviso that the
composition is substantially devoid of fluoride ions, are present
in the following amounts:
TABLE-US-00002 more most component preferably preferably preferably
weak about 0.1 about 0.1 about 1 acid(s) to about to about to about
15 wt % 5 wt % 5 wt % reducing about 0.1 about 0.1 about 0.1
agent(s) to about to about to about 10 wt % 5 wt % 2 wt % water
about 75 about 90 about 93 to about to about to about 99.8 wt %
99.8 wt % 98.9 wt %
[0039] In a preferred embodiment, the composition of the fourth
aspect comprises, consists of, or consists essentially of nitric
acid, ascorbic acid, and water. In another embodiment, the
composition of the fourth aspect comprises, consists of, or
consists essentially of sulfuric acid, ascorbic acid, and water. In
still another embodiment, the composition of the fourth aspect
comprises, consists of, or consists essentially of hydrochloric
acid, ascorbic acid, and water. In yet another embodiment, the
composition of the fourth aspect comprises, consists of, or
consists essentially of formic acid, ascorbic acid, and water.
Still another embodiment of the fourth aspect is a composition
comprising, consisting of, or consisting essentially of malonic
acid, ascorbic acid, and water. In another embodiment, the
composition of the fourth aspect comprises, consists of, or
consists essentially of sulfuric acid, ammonium sulfate, ascorbic
acid, and water. In each embodiment, the composition is
substantially devoid of fluoride ions.
[0040] The composition of the fourth aspect can further comprise at
least one reduced lanthanoid species, e.g., cerium (III) species,
solubilized therein. Accordingly, in another embodiment, the
composition comprises, consists of or consists essentially of at
least one strong acid, at least one reducing agent, at least one
reduced lanthanoid species, optionally at least one salt of the at
least one strong acid, and water, with the proviso that the
composition is substantially devoid of fluoride ions and when the
at least one strong acid is nitric acid and the at least one
reducing agent is hydrogen peroxide, the composition is
substantially devoid of (i) boric acid and (ii) an organic acid
having an active carboxylic acid group such as tartaric acid,
citric acid, lactic acid, gluconic acid and edetic acid. In yet
another embodiment, the composition comprises, consists of or
consists essentially of at least one weak acid, at least one
reducing agent, at least one reduced lanthanoid species, and water,
with the proviso that the composition is substantially devoid of
fluoride ions.
[0041] It will be appreciated that it is common practice to make
concentrated forms of the compositions to be diluted prior to use.
For example, the composition may be manufactured in a more
concentrated form, including at least one strong acid, at least one
reducing agent, optionally at least one salt of the at least one
strong acid, and water, with the proviso that the composition is
substantially devoid of fluoride ions and when the at least one
strong acid is nitric acid and the at least one reducing agent is
hydrogen peroxide, the composition is substantially devoid of (i)
boric acid and (ii) an organic acid having an active carboxylic
acid group such as tartaric acid, citric acid, lactic acid,
gluconic acid and edetic acid, and thereafter diluted with water at
the manufacturer, before use, and/or during use at the fab. In
another embodiment, the composition may comprise, consist of or
consist essentially of at least one weak acid, at least one
reducing agent, at least one reduced lanthanoid species, and water,
with the proviso that the composition is substantially devoid of
fluoride ions, and thereafter diluted with water at the
manufacturer, before use, and/or during use at the fab. Dilution
ratios may be in a range from about 0.1 part diluent:1 part
composition concentrate to about 100 parts diluent:1 part
composition concentrate.
[0042] The compositions of the invention are easily formulated by
simple addition of the respective ingredients and mixing to
homogeneous condition. Furthermore, the compositions may be readily
formulated as single-package formulations or multi-part
formulations that are mixed at or before the point of use,
preferably multi-part formulations. The individual parts of the
multi-part formulation may be mixed at the tool or in a mixing
region/area such as an inline mixer or in a storage tank upstream
of the tool. It is contemplated that the various parts of the
multi-part formulation may contain any combination of
ingredients/constituents that when mixed together form the desired
composition. The concentrations of the respective ingredients may
be widely varied in specific multiples of the composition, i.e.,
more dilute or more concentrated, and it will be appreciated that
the compositions described herein can variously and alternatively
comprise, consist or consist essentially of any combination of
ingredients consistent with the disclosure herein.
[0043] Accordingly, a fifth aspect relates to a kit including, in
one or more containers, one or more components adapted to form the
compositions described herein. Preferably, the kit includes, in one
or more containers, at least one strong acid, at least one reducing
agent, optionally at least one salt of the at least one strong
acid, and optionally water, for combining with water at the fab or
the point of use. Optionally, the containers of the kit may include
at least one weak acid, at least one reducing agent, and optionally
water, for combining with water and/or oxidizing agent(s) at the
fab or the point of use. The containers of the kit must be suitable
for storing and shipping said removal compositions, for example,
NOWPak.RTM. containers (Advanced Technology Materials, Inc.,
Danbury, Conn., USA). The one or more containers which contain the
components of the composition preferably include means for bringing
the components in said one or more containers in fluid
communication for blending and dispense. For example, referring to
the NOWPak.RTM. containers, gas pressure may be applied to the
outside of a liner in said one or more containers to cause at least
a portion of the contents of the liner to be discharged and hence
enable fluid communication for blending and dispense.
Alternatively, gas pressure may be applied to the head space of a
conventional pressurizable container or a pump may be used to
enable fluid communication. In addition, the system preferably
includes a dispensing port for dispensing the blended removal
composition to a process tool.
[0044] Substantially chemically inert, impurity-free, flexible and
resilient polymeric film materials, such as high density
polyethylene, are preferably used to fabricate the liners for said
one or more containers. Desirable liner materials are processed
without requiring co-extrusion or barrier layers, and without any
pigments, UV inhibitors, or processing agents that may adversely
affect the purity requirements for components to be disposed in the
liner. A listing of desirable liner materials include films
comprising virgin (additive-free) polyethylene, virgin
polytetrafluoroethylene (PTFE), polypropylene, polyurethane,
polyvinylidene chloride, polyvinylchloride, polyacetal,
polystyrene, polyacrylonitrile, polybutylene, and so on. Preferred
thicknesses of such liner materials are in a range from about 5
mils (0.005 inch) to about 30 mils (0.030 inch), as for example a
thickness of 20 mils (0.020 inch).
[0045] Regarding the containers for the kits, the disclosures of
the following patents and patent applications are hereby
incorporated herein by reference in their respective entireties:
U.S. Pat. No. 7,188,644 entitled "APPARATUS AND METHOD FOR
MINIMIZING THE GENERATION OF PARTICLES IN ULTRAPURE LIQUIDS;" U.S.
Pat. No. 6,698,619 entitled "RETURNABLE AND REUSABLE, BAG-IN-DRUM
FLUID STORAGE AND DISPENSING CONTAINER SYSTEM;" and PCT/US08/63276
entitled "SYSTEMS AND METHODS FOR MATERIAL BLENDING AND
DISTRIBUTION" filed on May 9, 2008 in the name of Advanced
Technology Materials, Inc.
[0046] A sixth aspect of the invention relates to the removal of
post-etch residue, post-ash residue, post-chemical mechanical
polishing residue, and other contaminants and/or by-products of the
microelectronic device manufacturing process, said method
comprising contacting a surface of a microelectronic device having
said residue, contaminants and/or by-products thereon with a
composition of the fourth aspect to substantially remove said
residue, contaminants and/or by-products from the surface.
[0047] Another aspect relates to the improved microelectronic
devices made according to the methods of the invention and to
products containing such microelectronic devices.
[0048] A still further aspect relates to methods of manufacturing
an article comprising a microelectronic device, said method
comprising contacting a surface of the microelectronic device with
a composition for sufficient time to substantially dissolve
lanthanoid-containing solids and/or species from the surface, and
incorporating said microelectronic device into said article.
Preferably, the lanthanoid comprises cerium.
[0049] Yet another aspect relates to an article of manufacture
comprising a composition and a surface comprising
lanthanoid-containing solids and/or species, wherein the
composition comprises, consists of or consists essentially of at
least one strong acid, at least one reducing agent, optionally at
least one salt of the at least one strong acid, and water, with the
proviso that the composition is substantially devoid of fluoride
ions and when the at least one strong acid is nitric acid and the
at least one reducing agent is hydrogen peroxide, the composition
is substantially devoid of (i) boric acid and (ii) an organic acid
having an active carboxylic acid group such as tartaric acid,
citric acid, lactic acid, gluconic acid and edetic acid.
Alternatively, the composition comprises, consists of or consists
essentially of at least one weak acid, at least one reducing agent,
and water, with the proviso that the composition is substantially
devoid of fluoride ions.
[0050] Another aspect relates to a method for removing photoresist
from a surface, said method comprising contacting the photoresist
with a solution comprising cerium to substantially remove the
photoresist, and contacting the surface with a composition that
substantially removes the lanthanoid-containing species present on
the surface. Prior to contacting the photoresist with the solution,
it is assumed that the photoresist has been ion-implanted by
greater than approximately 5.times.10.sup.14 ions per square
centimeter, and/or ions having an average energy, before the ions
impact the photoresist, greater than approximately five thousand
electron volts (5 KeV). Preferably, the surface comprises TiN.
Preferably, the solution used to remove the resist or photoresist
comprises cerium ammonium nitrate. Preferably, the composition that
substantially removes the lanthanoid-containing species is one of
the compositions of the fourth aspect described herein.
[0051] In another aspect, a method for removing a masking material
is described, the method comprising: contacting the masking
material with a solution comprising cerium and contacting the
surface with a composition that substantially removes the
lanthanoid-containing species present on the surface, wherein the
masking material is comprised within a layer formed on at least a
first portion of a surface, and wherein the masking material blocks
at least a first portion of dopant material from contacting the at
least a first portion of the surface, and wherein the first portion
of the dopant material comprises ions implanted into the masking
material. Ions implanted into the masking material can comprise at
least one of: boron; boron trifluoride; indium; gallium; thallium;
germanium; bismuth; arsenic; phosphorus; xenon and antimony.
Preferably, the solution used to remove the resist or photoresist
comprises cerium ammonium nitrate. Preferably, the composition that
substantially removes the lanthanoid-containing species is one of
the compositions of the fourth aspect described herein.
[0052] Still another aspect relates to the removal of manganese
oxide particles from the surface of microfabrication hardware, said
method comprising contacting the surface of the hardware with a
composition that substantially removes the manganese oxide
particles from the surface. Manganese oxide particles are often the
byproduct of a composition that includes permanganate, whether
present as a permanganate salt or generated in situ, wherein the
manganese oxide particles deposit on the surface of the
microfabrication hardware as well as on wafers. It was surprisingly
discovered that the compositions described herein, are effective at
dissolving these manganese-containing precipitates under the
process conditions described herein to remove lanthanum-containing
species.
[0053] The features and advantages of the invention are more fully
illustrated by the following non-limiting examples, wherein all
parts and percentages are by weight, unless otherwise expressly
stated.
EXAMPLE 1
[0054] To test the capability of various solutions to dissolve
Ce(IV)-containing precipitates, the precipitates were generated by
heating a 20% cerium ammonium nitrate (CAN) solution in deionized
water at 70.degree. C. for 20 hours. A substantial amount of yellow
precipitate was formed and settled at the bottom of the bottle. The
solution was decanted, leaving behind a slurry of precipitate in
residual CAN solution. The dissolution of 0.05-0.1 ml of the slurry
was then tested at room temperature in test tubes, in the presence
of 3-6 ml water, some acid, and some reducing agent. The mixture
was shaken vigorously in the capped test tube for 0.5-2 minutes and
then periodically as needed. The dissolution was considered
successful if the solution was colorless and clear within 1 minute;
however, it should be understood that much longer process times
and/or temperatures higher than ambient may be acceptable. [0055]
Solution 1: 0.2 g ascorbic acid, 4 g dilute HNO.sub.3 (1 part by
weight of conc. HNO.sub.3:3 parts by weight water, hereinafter the
"1:3 HNO.sub.3 solution"), 0.1 mL slurry. The original dark color
and turbidity disappears in less than 1 min. Two additional 0.1 mL
slurry additions were quickly dissolved as well. [0056] Solution 2:
0.2 g ascorbic acid, 4 g water, 0.1 mL slurry. No obvious effect.
After adding 1 g of 1:3 HNO.sub.3 and shaking, the turbidity and
color quickly disappeared. [0057] Solution 3: 0.1 g ascorbic acid,
4 g water, 1 g 1:3 HNO.sub.3, 0.1 mL slurry. All turbidity and
color disappeared within 80 sec. [0058] Solution 4: 0.1 g ascorbic
acid, 3.6 g water, 0.5 g 4 M H.sub.2SO.sub.4, 0.1 mL slurry. All
turbidity and color disappeared within 20 sec. [0059] Solution 5:
0.11 g ascorbic acid, 4.9 g water, 0.1 g 95% H.sub.2SO.sub.4, 0.1
mL slurry. All turbidity and color disappeared within 40 sec.
[0060] Solution 6: 0.05 g ascorbic acid, 4.9 g water, 0.1 g 95 wt %
H.sub.2SO.sub.4, 0.05 mL slurry. All turbidity and color
disappeared within 30 sec. When another 0.05 mL slurry was added,
all turbidity and color disappeared within 40 sec. [0061] Solution
7: 0.05 g ascorbic acid, 2 g 1 M HCl, 3 g water, 0.05 mL slurry.
The dark brown color faded slowly and was clear after 4 min. [0062]
Solution 8: 0.060 g ascorbic acid, .about.5 g water, 0.110 g 95%
H.sub.2SO.sub.4, 0.189 g (NH.sub.4).sub.2SO.sub.4, water to obtain
a total of 6 g, mix, and then 0.1 mL slurry. No dark color
observed, but turbidity disappears after about 1 minute. Note that
this mixture is part NH.sub.4HSO.sub.4, part
(NH.sub.4).sub.2SO.sub.4. [0063] Solution 9: 0.055 g ascorbic acid,
5.9 g water, 0.24 g 95% formic acid, 0.06 mL slurry. All turbidity
and color disappeared within 30 sec of shaking. [0064] Solution 10:
5.9 g water, 0.24 g 95% formic acid, 0.06 mL slurry. No significant
dissolution in .about.3 minutes, but following the addition of
.about.50 mg ascorbic acid, rapid dissolution occurred (.about.30
sec). [0065] Solution 11: 0.05 g ascorbic acid, 0.25 g malonic
acid, 4.7 g water, 0.05 mL slurry. The solution initially was a
light brown color, which cleared after about 7 min.
[0066] Although not wishing to be bound by theory, these examples
suggest that the presence of an acid stronger than ascorbic acid is
useful for the speedy dissolution of Ce(IV)-containing particles.
The solutions, which were devoid of fluoride, were effective at
dissolving the Ce(IV)-containing particles even at room temperature
without damaging the surface.
[0067] Although the invention has been variously disclosed herein
with reference to illustrative embodiments and features, it will be
appreciated that the embodiments and features described hereinabove
are not intended to limit the invention, and that other variations,
modifications and other embodiments will suggest themselves to
those of ordinary skill in the art, based on the disclosure herein.
The invention therefore is to be broadly construed, as encompassing
all such variations, modifications and alternative embodiments
within the spirit and scope of the claims hereafter set forth.
* * * * *