U.S. patent application number 15/550630 was filed with the patent office on 2018-02-15 for coatings for enhancement of properties and performance of substrate articles and apparatus.
The applicant listed for this patent is Entegris, Inc.. Invention is credited to Richard A. Cooke, Nilesh Gunda, Bryan C. Hendrix, Weimin Li, I-Kuan Lin, David W. Peters, Carlo Waldfried.
Application Number | 20180044800 15/550630 |
Document ID | / |
Family ID | 56615146 |
Filed Date | 2018-02-15 |
United States Patent
Application |
20180044800 |
Kind Code |
A1 |
Hendrix; Bryan C. ; et
al. |
February 15, 2018 |
COATINGS FOR ENHANCEMENT OF PROPERTIES AND PERFORMANCE OF SUBSTRATE
ARTICLES AND APPARATUS
Abstract
Coatings applicable to a variety of substrate articles,
structures, materials, and equipment are described. In various
applications, the substrate includes metal surface susceptible to
formation of oxide, nitride, fluoride, or chloride of such metal
thereon, wherein the metal surface is configured to be contacted in
use with gas, solid, or liquid that is reactive therewith to form a
reaction product that is deleterious to the substrate article,
structure, material, or equipment. The metal surface is coated with
a protective coating preventing reaction of the coated surface with
the reactive gas, and/or otherwise improving the electrical,
chemical, thermal, or structural properties of the substrate
article or equipment. Various methods of coating the metal surface
are described, and for selecting the coating material that is
utilized.
Inventors: |
Hendrix; Bryan C.; (Danbury,
CT) ; Peters; David W.; (Kingsland, TX) ; Li;
Weimin; (New Milford, CT) ; Waldfried; Carlo;
(Middleton, MN) ; Cooke; Richard A.; (Framingham,
MA) ; Gunda; Nilesh; (Chelmsford, MA) ; Lin;
I-Kuan; (Lexington, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Entegris, Inc. |
Billerica |
MA |
US |
|
|
Family ID: |
56615146 |
Appl. No.: |
15/550630 |
Filed: |
February 13, 2016 |
PCT Filed: |
February 13, 2016 |
PCT NO: |
PCT/US16/17910 |
371 Date: |
August 11, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62116181 |
Feb 13, 2015 |
|
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|
62167890 |
May 28, 2015 |
|
|
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62188333 |
Jul 2, 2015 |
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62221594 |
Sep 21, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C 14/50 20130101;
C23C 16/45555 20130101; C23C 16/45525 20130101; C23C 28/044
20130101; C23C 16/403 20130101; C23C 16/4412 20130101; C23C 16/4404
20130101; C23C 16/404 20130101; C23C 16/56 20130101; C23C 28/042
20130101; C23C 16/405 20130101; C23C 14/243 20130101; C23C 16/042
20130101 |
International
Class: |
C23C 28/04 20060101
C23C028/04; C23C 16/40 20060101 C23C016/40; C23C 16/455 20060101
C23C016/455; C23C 14/24 20060101 C23C014/24; C23C 14/50 20060101
C23C014/50 |
Claims
1. (canceled)
2. The apparatus of claim 88, wherein the metal oxide comprises at
least one oxide of one or more of Cr, Fe, Co, and Ni.
3. The apparatus of claim 2, wherein the metal surface comprises
stainless steel surface, aluminum surface, or anodized aluminum
surface.
4. The apparatus of claim 88, wherein the gas that is reactive with
the metal oxide to form a reaction product that is deleterious to
the apparatus and its use or operation, comprises
Al.sub.2Cl.sub.6.
5. (canceled)
6. The apparatus of claim 88, wherein the protective coating
comprises Al.sub.2O.sub.3.
7. The apparatus of claim 88, wherein the protective coating
comprises one or more of coating material selected from the group
consisting of oxides of the formula MO, wherein M is Ca, Mg, or Be,
and oxides of the formula M'O.sub.2, wherein M' is a
stoichiometrically acceptable metal.
8. The apparatus of claim 88, wherein the protective coating
comprises one or more of coating material selected from the group
consisting of oxides of the formula Ln.sub.2O.sub.3, wherein Ln is
a lanthanide element.
9. The apparatus of claim 8, wherein Ln is La, Sc, or Y.
10. The apparatus of claim 88, wherein the protective coating
comprises a metal oxide for which the free energy of reaction with
the gas that is contacted with the metal surface in the use or
operation of said structure, material, or apparatus, is greater
than or equal to zero.
11. A method of improving performance of a structure, material, or
apparatus comprising metal surface susceptible to formation of
oxide, nitride, or halide of said metal thereon, wherein the metal
surface is configured to be contacted in use or operation of said
apparatus with gas, solid, or liquid that is reactive with said
metal oxide, nitride, or halide to form a reaction product that is
deleterious to said apparatus and its use or operation, said method
comprising coating the metal surface with a protective coating
capable of preventing reaction of the coated surface with the
reactive gas, solid, or liquid, wherein the coating comprises
multiple layers formed by atomic layer deposition, and wherein the
protective coating comprises one or more of coating materials
selected from the group consisting of Al.sub.2O.sub.3; oxides of
the formula MO, wherein M is Ca, Mg, or Be; oxides of the formula
M'O.sub.2, wherein M' is a stoichiometrically acceptable metal; and
oxides of the formula Ln.sub.2O.sub.3, wherein Ln is a lanthanide
element.
12-38. (canceled)
39. The apparatus of claim 88, wherein the protective coating
comprises at least two metal oxides selected from the group
consisting of titania, alumina, zirconia, oxides of the formula MO
wherein M is Ca, Mg, or Be, oxides of the formula M'O.sub.2,
wherein M' is a stoichiometrically acceptable metal, and oxides of
the formula Ln.sub.2O.sub.3 wherein Ln is a lanthanide element, La,
Sc, or Y.
40. The apparatus claim 88, wherein the protective coating
comprises least one layer of alumina.
41. The apparatus of claim 88, wherein the protective coating
comprises least one layer of titania.
42. The apparatus of claim 88, wherein the protective coating
comprises at least one layer of zirconia.
43.-55. (canceled)
56. The apparatus of claim 88, wherein the apparatus comprises a
vapor deposition furnace.
57. The apparatus of claim 88 comprising a vessel defining an
interior volume including support surface therein for solid
material to be vaporized, wherein at least a portion of the support
surface has the protective coating thereon.
58. The apparatus of claim 57, wherein the support surface
comprises interior surface of the vessel.
59. The apparatus of claim 57, wherein the support surface
comprises surface of a support member in the interior volume.
60. The apparatus of claim 59, wherein the support member comprises
a tray providing support surface for the solid material.
61. (canceled)
62. The apparatus of claim 57, wherein the vessel contains an array
of vertically spaced apart trays, each providing support surface
for the solid material.
63.-65. (canceled)
66. The apparatus of claim 88, wherein the protective coating has a
thickness in a range of from 2 to 500 nm.
67.-78. (canceled)
79. The apparatus of claim 88, wherein the surface is a surface of
a substrate part that has at least one high aspect ratio
feature.
80. The apparatus of claim 79, wherein the at least one high aspect
ratio feature comprises a feature selected from the group
consisting of deep holes, channels, 3-dimensional features,
hardware, screws, nuts, porous membranes, filters, 3-dimensional
network structures, and structures with connected pore
matrices.
81.-87. (canceled)
88. A semiconductor manufacturing apparatus comprising metal
surface susceptible to formation of oxide of said metal thereon,
the metal surface configured to be contacted in operation of said
apparatus with gas, solid, or liquid that is reactive with said
metal oxide to form a reaction product that is deleterious to said
apparatus and its operation, wherein the metal surface is coated
with a protective coating capable of preventing reaction of the
coated surface with the reactive gas, solid, or liquid wherein the
protective coating comprises multiple layers formed by atomic layer
deposition, and wherein the protective coating comprises one or
more of coating materials selected from the group consisting of
Al.sub.2O.sub.3; oxides of the formula MO, wherein M is Ca, Mg, or
Be; oxides of the formula M'O.sub.2, acceptable metal; and oxides
of the formula Ln.sub.2O.sub.3, wherein Ln is a lanthanide
element.
89.-134. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to International
Application No. PCT/US2016/017910, filed Feb. 13, 2016, which in
turn claims the benefit under the provisions of 35 U.S. C.
.sctn.119 of the following U.S. provisional patent applications:
U.S. Provisional Patent Application No. 62/116,181 filed Feb. 13,
2015 in the names of Carlo Waldfried, et al. for "THIN FILM ATOMIC
LAYER DEPOSITION COATINGS"; U.S. Provisional Patent Application No.
62/167,890 filed May 28, 2015 in the names of Bryan C. Hendrix, et
al. for "COATINGS TO PREVENT TRANSPORT OF TRACE METALS BY AL2CL6
VAPOR"; U.S. Provisional Patent Application No. 62/188,333 filed
Jul. 2, 2015 in the names of Bryan C. Hendrix, et al. for "COATINGS
FOR ENHANCEMENT OF PROPERTIES AND PERFORMANCE OF SUBSTRATE ARTICLES
AND APPARATUS"; and U.S. Provisional Patent Application No.
62/221,594 filed Sep. 21, 2015 in the names of Bryan C. Hendrix, et
al. for "COATINGS FOR ENHANCEMENT OF PROPERTIES AND PERFORMANCE OF
SUBSTRATE ARTICLES AND APPARATUS". The disclosures of such U.S.
Provisional Patent Application Nos. 62/116,181, 62/167,890,
62/188,333, and 62/221,594 are hereby incorporated herein by
reference, in their respective entireties, for all purposes.
FIELD
[0002] The present disclosure generally relates to coatings
applicable to a variety of substrate articles and equipment, e.g.,
in respect of structures and apparatus having surface that is
susceptible to formation thereon of undesired oxide, nitride,
fluoride, chloride, or other halide contaminant species. In
specific aspects, the disclosure relates to semiconductor
manufacturing equipment and methods of enhancing the performance
thereof, and more specifically relates to semiconductor
manufacturing equipment susceptible to contamination and particle
deposition associated with the presence of dialuminum hexachloride
vapor in such equipment, and to compositions and methods for
combating such adverse contamination and particle deposition.
DESCRIPTION OF THE RELATED ART
[0003] In many fields of endeavor, structures, materials, and
apparatus are encountered that include surface susceptible to
formation of contaminant species, such as surfaces of aluminum,
anodized aluminum, quartz, stainless steel, etc. that are
susceptible to formation of undesired oxide, nitride, and halide
(e.g., fluoride and/or chloride) contaminant species thereon, which
interfere with the use, utility, or function of the associated
products, equipment, or materials.
[0004] In the field of semiconductor manufacturing, aluminum and
aluminum-containing materials are widely employed. Although
aluminum as a metallization material has been significantly
displaced by copper in nanoscale integrated circuitry applications,
aluminum nonetheless continues to be extensively utilized as a wire
bonding and connection material, as well as use in thin film
materials, e.g., AlN thin films as barrier layers, piezoelectric
device components, cold cathode materials, etc., as well as in
compound semiconductor compositions for applications such as LEDs
and other optoelectronic devices or Al.sub.2O.sub.3 layers as
dielectrics, dielectric dopants, barriers, optical coatings,
etc.
[0005] In many of such applications, halogen gases are employed in
semiconductor manufacturing equipment for processing of films in
the device manufacturing operation, or as co-flow cleaning agents
for removal of accumulated contaminant deposits on surfaces and
components of the semiconductor manufacturing equipment. These
halogen gases may include chloro species, which can reactively form
dialuminum hexachloride (Al.sub.2Cl.sub.6) vapor when contacting
aluminum present in the equipment, e.g., on wafers, or on surfaces
or components of the equipment. Such dialuminum hexachloride vapor
may in turn attack stainless steel surfaces and components in the
semiconductor manufacturing equipment and serve to transport
measurable levels of metals such as chromium, iron, and nickel to
the wafers undergoing processing.
[0006] Another class of applications uses Al.sub.2Cl.sub.6 vapor to
deposit aluminum containing films. Although Al.sub.2O.sub.3 is
widely deposited by ALD using trimethyl aluminum as a source
reagent, trimethyl aluminum nonetheless is a pyrophoric liquid
subject to significant safety and regulatory costs.
Al.sub.2Cl.sub.6 vapor can be readily produced above solid
AlCl.sub.3 in a solid vaporizer, such as solid vaporizer units of
the type commercially sold under the trademark ProE-Vap by
Entegris, Inc., Billerica, Mass., USA.
[0007] Stainless steel components of semiconductor and
manufacturing equipment may be formed of 316 stainless steel or
other stainless steel alloys that are generally electropolished.
Such electropolishing generally leaves the surface coated with a
layer of passive oxide containing chromium, iron, nickel, and other
alloy components. In addition, such metal components may form
surface traces of corresponding oxides by native oxidation
processes. As a result, when dialuminum hexachloride encounters
such metal oxides, the metal oxides react with the dialuminum
hexachloride to form corresponding vapor phase metalloaluminum
chloride compounds which can transport to wafers and semiconductor
devices or device precursor structures and may deposit the trace
metals or otherwise damage the products being manufactured in the
equipment. Alternatively, the metal oxide can react with
Al.sub.2Cl.sub.6 vapor to form Al.sub.2O.sub.3 and particulate
metal chlorides that can transport to the device structure and
cause damage. Additionally, AlCl.sub.3 solid can contact the metal
oxide surface to form either vapor metalloaluminum chloride or
solid chloride particles.
[0008] In consequence, it would be a significant improvement to
suppress the deleterious interaction of dialuminum hexachloride
with metal surfaces and components in such semiconductor
manufacturing equipment and other thin film deposition or etching
equipment.
[0009] There is also an ongoing need for coatings for a variety of
industrial applications that are dense, pinhole-free and
defect-free, and provide other coating qualities and advantages,
such as electrical insulation of parts, the ability to coat parts
conformally, chemical and etch resistance, corrosion resistance,
diffusion barrier properties, and adhesion layer properties.
SUMMARY
[0010] The present disclosure generally relates to coatings
applicable to a variety of substrate articles, structures,
materials, and equipment, and relates in specific aspects to
semiconductor manufacturing equipment and methods of enhancing the
performance thereof, and more specifically to semiconductor
manufacturing equipment susceptible to contamination and particle
deposition associated with the presence of dialuminum hexachloride
in such equipment, and to compositions and methods for combating
such adverse contamination and particle deposition.
[0011] The disclosure relates in one aspect to a structure,
material, or apparatus comprising metal surface susceptible to
formation of oxide, nitride, or halide of said metal thereon, the
metal surface configured to be contacted in use or operation of
said structure, material, or apparatus with gas, solid, or liquid
that is reactive with such metal oxide, nitride, or halide, to form
a reaction product that is deleterious to said structure, material,
or apparatus and its use or operation, wherein the metal surface is
coated with a protective coating preventing reaction of the coated
surface with the reactive gas.
[0012] In one aspect, the disclosure relates to a semiconductor
manufacturing apparatus comprising metal surface susceptible to
formation of oxide, nitride, or halide of said metal thereon, the
metal surface configured to be contacted in operation of said
apparatus with gas, solid, or liquid that is reactive with said
metal oxide, nitride, or halide to form a reaction product, e.g., a
particulate reaction product and/or a vapor reaction product, that
is deleterious to said apparatus and its operation, wherein the
metal surface is coated with a protective coating preventing
reaction of the coated surface with the reactive gas.
[0013] A further aspect of the disclosure relates to a method of
improving performance of a structure, material, or apparatus
comprising metal surface susceptible to formation of oxide,
nitride, or halide of said metal thereon, wherein the metal surface
is configured to be contacted in use or operation of said
structure, material, or apparatus with gas, solid, or liquid that
is reactive with said metal oxide, nitride, or halide to form a
reaction product that is deleterious to said structure, material,
or apparatus and its use or operation, said method comprising
coating the metal surface with a protective coating preventing
reaction of the coated surface with the reactive gas.
[0014] In another aspect, the disclosure relates to a method of
improving performance of a semiconductor manufacturing apparatus
comprising metal surface susceptible to formation of oxide,
nitride, or halide of said metal thereon, wherein the metal surface
is configured to be contacted in operation of said apparatus with
gas, solid, or liquid that is reactive with the metal oxide,
nitride, or halide to form a reaction product that is deleterious
to said apparatus and its operation, such method comprising coating
the metal surface with a protective coating preventing reaction of
the coated surface with the reactive gas.
[0015] In another aspect, the disclosure relates to improving the
performance of a semiconductor manufacturing apparatus in contact
with a reactive solid.
[0016] In accordance with a further aspect of the disclosure, there
are provided thin film atomic layer deposition coatings for
industrial applications. Thin film coatings in accordance with the
disclosure are described in the specification herein.
[0017] Another aspect of the disclosure relates to a composite ALD
coating, comprising layers of different ALD product materials.
[0018] A further aspect of the disclosure relates to a composite
coating, comprising at least one ALD layer and at least one
deposited layer that is not an ALD layer.
[0019] In another aspect, the disclosure relates to a method of
forming a patterned ALD coating on a substrate, comprising forming
a pattern on the substrate of a layer of surface termination
material that is effective to prevent ALD film growth.
[0020] In another aspect, the disclosure relates to a method of
filling and/or sealing surface infirmities of a material, said
method comprising applying an ALD coating on a surface infirmity of
the material, at a thickness effecting filling and/or sealing of
the infirmity.
[0021] A further aspect of the disclosure relates to a filter,
comprising a matrix of fibers and/or particles, the fibers and/or
particles being formed of metal and/or polymeric material, wherein
the matrix of fibers and/or particles has an ALD coating thereon,
wherein the ALD coating does not alter pore volume of the matrix of
fibers and/or particles by more than 5%, as compared to a
corresponding matrix of fibers and/or particles lacking said ALD
coating thereon, and wherein when the fibers and/or particles are
formed of metal, and the ALD coating comprises metal, the metal of
the ALD coating is different from the metal of the fibers and/or
particles.
[0022] Yet another aspect of the disclosure relates to a method of
delivering a gaseous or vapor stream to a semiconductor processing
tool, said method comprising providing a flow path for the gaseous
or vapor stream, from a source of said gaseous or vapor stream to
the semiconductor processing tool, and flowing the gaseous or vapor
stream through a filter in the flow path to remove extraneous solid
material from the stream, wherein the filter comprises a filter of
the present disclosure, as variously described herein.
[0023] The disclosure in a further aspect relates to a filter
comprising a sintered matrix of stainless steel fibers and/or
particles that is coated with an ALD coating of alumina, wherein
the sintered matrix comprises pores of a diameter in a range of
from 1 to 40 .mu.m, e.g., from 10 to 20 .mu.m, and the ALD coating
has a thickness in a range of from 2 to 500 nm.
[0024] Another aspect of the disclosure relates to a solid
vaporizer apparatus comprising a vessel defining an interior volume
including support surface therein for solid material to be
vaporized, wherein at least a portion of the support surface has an
ALD coating thereon.
[0025] The disclosure relates in a further aspect to a thin film
coating comprised of one or more layers, wherein at least one layer
is deposited by atomic layer deposition.
[0026] Another aspect of the disclosure relates to an ALD coating
having a film thickness exceeding 1000 .ANG..
[0027] A further aspect of the disclosure relates to an ALD coating
comprising a very dense, pinhole free, defect-free layer.
[0028] Yet another aspect of the disclosure relates to a thin film
coating deposited on a part surface other than an integrated
circuit device on a silicon wafer.
[0029] In a further aspect, the disclosure relates to an ALD
coating comprised of insulating metal oxide and metal.
[0030] Another aspect the disclosure relates to an ALD coating that
is depositable at temperature in a range of from 20.degree. C. to
400.degree. C.
[0031] A further aspect of the disclosure relates to an ALD coating
comprising a single film having a defined stoichiometry.
[0032] Another aspect of the disclosure relates to a thin film
coating comprising an ALD layer in combination with at least one
other layer deposited by a different deposition technique.
[0033] In another aspect, the disclosure relates to a multilayer
ALD coating, having a coating thickness not exceeding 2 .mu.m.
[0034] Another aspect of the disclosure relates to an ALD coating
of material selected from the group consisting of oxides, alumina,
aluminum-oxy nitride, yttria, yttria-alumina mixes, silicon oxide,
silicon oxy-nitride, transition metal oxides, transition metal
oxy-nitrides, rare earth metal oxides, and rare earth metal
oxy-nitrides.
[0035] A further aspect of the disclosure relates to a method of
forming a patterned ALD coating on a substrate part, such method
comprising: uniformly coating the part with an ALD coating; and
etching back unwanted coating material through a mask.
[0036] Another method aspect of the disclosure relates to a method
of forming a patterned ALD coating on a substrate part, such method
comprising: masking an area of the part; coating the part with an
ALD coating; and removing the ALD coating from the mask area of the
part.
[0037] A still further method aspect of the disclosure relates to a
method of forming a patterned ALD coating on a substrate part, such
method comprising: patterning the substrate part with material
comprising a surface termination component that blocks the ALD film
growth; and coating the patterned substrate part with an ALD
coating.
[0038] A further aspect of the disclosure relates to a method of
electrically insulating a substrate part, comprising applying to
said substrate part a defect-free, pin-hole-free, dense,
electrically insulating ALD coating.
[0039] The disclosure relates in another aspect to a coating on a
substrate surface, comprising an ALD coating having a chemically
resistant and etch-resistant character.
[0040] Another aspect of the disclosure relates to a coating on a
substrate surface, comprising an ALD corrosion-resistant
coating.
[0041] A further aspect of the disclosure relates to a coating on a
substrate surface, comprising an ALD diffusion barrier layer.
[0042] A still further aspect of the disclosure relates to a
coating on a substrate surface, comprising an ALD adhesion
layer.
[0043] Yet another aspect of the disclosure relates to a coating on
a substrate surface, comprising an ALD surface sealant layer.
[0044] In another aspect, the disclosure relates to a porous filter
comprising a fibrous metal membrane coated with a chemically
resistant ALD coating.
[0045] A further aspect of the disclosure relates to a filter
comprising a porous material matrix coated with an ALD coating
wherein the average pore size of the porous metal matrix has been
reduced by the ALD coating, in relation to a corresponding porous
material matrix not coated with the ALD coating.
[0046] Another aspect of the disclosure relates to a filter
comprising a porous material matrix coated with an ALD coating,
wherein the coating thickness is directionally varied to provide a
corresponding pore size gradient in the filter.
[0047] In a further aspect, the disclosure relates to a method of
fabricating a porous filter, comprising coating a porous material
matrix with an ALD coating, to reduce average pore size of the
porous material matrix.
[0048] In another aspect, the disclosure relates to a solid
vaporizer apparatus comprising a container defining therein an
interior volume, an outlet configured to discharge precursor vapor
from the container, and support structure in the interior volume of
the container adapted to support solid precursor material thereon
for volatilization thereof to form the precursor vapor, wherein the
solid precursor material comprises aluminum precursor, and wherein
at least part of surface area in the interior volume is coated with
an alumina coating.
[0049] A further aspect the disclosure relates to a method of
enhancing corrosion resistance of a stainless steel structure,
material, or apparatus that in use or operation is exposed to
aluminum halide, said method comprising coating said stainless
steel structure, material, or apparatus with an alumina
coating.
[0050] Another aspect of the disclosure relates to a semiconductor
processing etching structure, component, or apparatus that in use
or operation is exposed to etching media, said structure,
component, or apparatus being coated with a coating comprising a
layer of yttria, wherein the layer of yttria optionally overlies a
layer of alumina in said coating.
[0051] Yet another aspect of the disclosure relates to a method of
enhancing corrosion resistance and etch resistance of a
semiconductor processing etching structure, component, or apparatus
that in use or operation is exposed to etching media, said method
comprising coating the structure, component, or apparatus with a
coating comprising a layer of yttria, wherein the layer of yttria
optionally overlies a layer of alumina in said coating.
[0052] Another aspect, the disclosure relates to a etch chamber
diffuser plate comprising a nickel membrane encapsulated with an
alumina coating.
[0053] A further aspect of the disclosure relates to a method of
enhancing corrosion resistance and etch resistance to an etch
chamber diffuser plate comprising a nickel membrane, comprising
coating the nickel membrane with an encapsulating coating of
alumina.
[0054] In another aspect, the disclosure relates to a vapor
deposition processing structure, component, or apparatus that in
use or operation is exposed to halide media, said structure,
component, or apparatus being coated with a coating of yttria
comprising an ALD base coating of yttria, and a PVD over coating of
yttria.
[0055] In still another aspect, the disclosure relates to a method
of enhancing corrosion resistance and etch resistance of a vapor
deposition processing structure, component, or apparatus that in
use or operation is exposed to halide media, said method comprising
coating the structure, component, or apparatus with a coating of
yttria comprising an ALD base coating of yttria, and a PVD over
coating of yttria.
[0056] Yet another aspect of the disclosure relates to a quartz
envelope structure coated on an interior surface thereof with an
alumina diffusion barrier layer.
[0057] A further aspect of the disclosure relates to a method of
reducing diffusion of mercury into a quartz envelope structure
susceptible to such diffusion in operation thereof, said method
comprising coating an interior surface of the quartz envelope
structure with an alumina diffusion barrier layer.
[0058] A still further aspect of the disclosure relates to a plasma
source structure, component, or apparatus that in use or operation
is exposed to plasma and voltage exceeding 1000 V, wherein
plasma-wetted surface of said structure, component or apparatus is
coated with an ALD coating of alumina, and said alumina coating is
overcoated with a PVD coating of aluminum oxynitride.
[0059] The disclosure in one aspect relates to a method of
enhancing service life of a plasma source structure, component, or
apparatus that in use or operation is exposed to plasma and voltage
exceeding 1000 V, said method comprising coating plasma-wetted
surface of said structure, component or apparatus with an ALD
coating of alumina, and over coating said alumina coating with a
PVD coating of aluminum oxynitride.
[0060] The disclosure in another aspect relates to a dielectric
stack, comprising sequential layers including a base layer of
alumina, a nickel electrode layer thereon, an ALD alumina
electrical stand-off layer on the nickel electrode layer, a PVD
aluminum oxynitride thermal expansion buffer layer on the ALD
alumina electrical stand-off layer, and a CVD silicon oxynitride
wafer contact surface and electrical spacer layer on the PVD
aluminum oxynitride thermal expansion buffer layer.
[0061] The disclosure in another aspect relates to a plasma
activation structure, component, or apparatus, comprising aluminum
surface coated with one of the multilayer coatings of (i) and (ii):
(i) a base coat of CVD silicon on the aluminum surface, and a layer
of ALD zirconia on the base coat of CVD silicon; and (ii) a base
coat of CVD silicon oxynitride on the aluminum surface, and a layer
of ALD alumina on the base coat of CVD silicon oxynitride.
[0062] Another aspect of the disclosure relates to a method of
reducing particle formation and metal contamination for an aluminum
surface of a plasma activation structure, component, or apparatus,
said method comprising coating the aluminum surface with one of the
multilayer coatings of (i) and (ii): (i) a base coat of CVD silicon
on the aluminum surface, and a layer of ALD zirconia on the base
coat of CVD silicon; and (ii) a base coat of CVD silicon oxynitride
on the aluminum surface, and a layer of ALD alumina on the base
coat of CVD silicon oxynitride.
[0063] A porous matrix filter is contemplated in another aspect of
the disclosure, the porous matrix filter comprising a membrane
formed of stainless steel, nickel, or titanium, wherein the
membrane is encapsulated with alumina to a coating penetration
depth in a range of from 20 to 2000 .mu.m.
[0064] In a corresponding method aspect, the disclosure relates to
a method of making a porous matrix filter comprising encapsulating
a membrane formed of stainless steel, nickel, or titanium with
alumina to a coating penetration depth in a range of from 20 to
2000 .mu.m.
[0065] Other aspects, features and embodiments of the disclosure
will be more fully apparent from the ensuing description and
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0066] FIG. 1 is a schematic representation of a deposition furnace
of a semiconductor wafer processing tool according to one aspect of
the present disclosure.
[0067] FIG. 2 is a schematic representation of a deposition furnace
process system according to another aspect of the disclosure, for
coating wafers using Al.sub.2Cl.sub.6 vapor, utilizing a solid
source delivery vaporizer in the form of an ampoule for vaporizing
AlCl.sub.3 to form the Al.sub.2Cl.sub.6 vapor, wherein the trays
and internal surfaces of the ampoule are coated with
Al.sub.2O.sub.3, as well as all of the valves, tubing and filters
downstream of the ampoule being coated with Al.sub.2O.sub.3.
[0068] FIG. 3 is a perspective, partial breakaway view of a
vaporizer container having holders to help promote contact of a gas
with vapor from material supported by the holders.
[0069] FIG. 4 is a micrograph, at 15K magnification, of the surface
of a porous metal frit of a type usefully employed in filter
elements, according to another aspect of the disclosure.
[0070] FIG. 5 is a micrograph, at 20,000 times magnification, of
the surface of electropolished 316 L stainless steel having no
exposure to AlCl.sub.3.
[0071] FIG. 6 is a micrograph, at 1000 times magnification, of a
surface of electropolished 316 L stainless steel after exposure to
AlCl.sub.3 for 10 days at 120.degree. C. in an anhydrous
environment.
[0072] FIG. 7 is a micrograph, at 50,000 times magnification, of a
cross-section of electropolished 316 L stainless steel that did not
have any exposure to AlCl.sub.3.
[0073] FIG. 8 is a micrograph, at 20,000 times magnification, of
uncoated 316 L stainless steel after 10 days of exposure to
AlCl.sub.3 at 120.degree. C. in an anhydrous environment.
[0074] FIG. 9 is a micrograph, at 35,000 times magnification, of
electropolished 316 L stainless steel after 10 days of exposure to
AlCl.sub.3 at 120.degree. C. in an anhydrous environment, showing
multiple pits along the surface.
[0075] FIG. 10 is a micrograph, at 35,000 times magnification, of
electropolished 316 L stainless steel coated by 100 ALD cycles of
Al.sub.2O.sub.3 using trimethyl aluminum and water, prior to
exposure to anhydrous AlCl.sub.3 at 120.degree. C. for 10 days.
[0076] FIG. 11 is a micrograph, at 35,000 times magnification, of
electropolished 316 L stainless steel coated by 1000 ALD cycles of
Al.sub.2O.sub.3 using trimethyl aluminum and water, prior to
exposure to anhydrous AlCl.sub.3 at 120.degree. C. for 10 days.
[0077] FIG. 12 is a composite photograph of sample stainless steel
coupons, of which sample coupons 2 and 3 were coated with a 470
.ANG. thick coating of alumina, and sample coupons 12 and 13 were
uncoated, has photographed after nine days exposure to AlCl.sub.3
at 155.degree. C.
[0078] FIG. 13 is a top-down scanning electron microscope (SEM)
micrograph of an alumina-coated stainless steel sample after
exposure to WCl.sub.5 at 220.degree. C. for 10 days.
[0079] FIG. 14 is a focused ion beam (FIB) cross-section of the
edge of the coating in the sample of FIG. 13 after exposure to
WCl.sub.5 at 220.degree. C. for 10 days.
[0080] FIG. 15 is a perspective view of a stainless steel holder
usefully employed in a vaporizer ampoule for aluminum trichloride
(AlCl.sub.3) solid precursor delivery for an aluminum process, in
which the aluminum trichloride precursor is supported by the holder
and volatilized to form aluminum trichloride precursor vapor for
discharge from the vaporizer ampoule and transport through
associated flow circuitry to the aluminum process.
[0081] FIG. 16 is a perspective view of a stainless steel holder of
the type shown in FIG. 15, as coated by atomic layer deposition
with a coating of alumina thereon, so that the stainless steel
surface is encapsulated by the alumina coating in the corrosive
environment involving aluminum trichloride (AlCl.sub.3) exposure to
which the holder is subjected in use and operation of the vaporizer
ampoule.
[0082] FIG. 17 is a schematic elevation view of an alumina coating
applied by atomic layer deposition to a stainless steel substrate,
to provide corrosion resistance, prevent chemical reaction with the
substrate, and reduce metals contamination in use.
[0083] FIG. 18 shows channels of a plasma etch apparatus coated
with yttria (Y.sub.2O.sub.3).
[0084] FIG. 19 is a schematic elevation view of an yttria coating
applied by atomic layer deposition over alumina.
[0085] FIG. 20 is a photograph of a diffuser plate assembly,
including a stainless steel frame and a nickel filter membrane, as
coated with an alumina coating.
[0086] FIG. 21 is a schematic elevation view of the diffuser plate
assembly, in which the stainless steel frame and nickel membrane
are encapsulated with ALD alumina.
[0087] FIG. 22 is a schematic elevation view of a coating
structure, including an aluminum substrate, an ALD coating of
alumina, and a PVD coating of AlON.
[0088] FIG. 23 is a schematic elevation view of the layer structure
of a dielectric stack useful for hot chuck components, in which an
alumina substrate has an electrode metal thereon, on which is an
electrical stand-off layer of ALD alumina, on which is a PVD
coating of aluminum oxynitride, on which is a layer of chemical
vapor deposition (CVD) deposited silicon oxynitride (SiON).
[0089] FIG. 24 is a schematic elevation view of a multilayer stack
including a chemical vapor deposition-applied layer of silicon on
an aluminum substrate, with an ALD layer of zirconia on the CVD Si
layer.
[0090] FIG. 25 is a schematic elevation view of a multilayer stack
including a CVD layer of silicon oxynitride on an aluminum
substrate, and an ALD layer of alumina on the CVD SiON coating
layer.
[0091] FIG. 26 is a micrograph of porous material having a 1.5 mm
wall thickness and pore size of 2-4 .mu.m, coated with alumina by
atomic layer deposition.
[0092] FIG. 27 is a schematic representation of an encapsulated
membrane, comprising a membrane formed of stainless steel, nickel,
titanium, or other suitable material, which has been fully
encapsulated with alumina deposited by ALD.
[0093] FIG. 28 is a photomicrograph of a coated filter, wherein the
coating is alumina, having a coating penetration depth of 35
.mu.m.
[0094] FIG. 29 is a photomicrograph of a coated filter, wherein the
coating is alumina, having a coating penetration depth of 175
.mu.m
DETAILED DESCRIPTION
[0095] The present disclosure generally relates to coatings
applicable to a variety of substrate articles, materials,
structures, and equipment. In various aspects, the disclosure
relates to semiconductor manufacturing equipment and methods of
enhancing the performance thereof, and more specifically to
semiconductor manufacturing equipment susceptible to contamination
and particle deposition associated with the presence of dialuminum
hexachloride in such equipment, and to compositions and methods for
combating such adverse contamination and particle deposition.
[0096] As used herein, the identification of a carbon number range,
e.g., in C.sub.1-C.sub.12 alkyl, is intended to include each of the
component carbon number moieties within such range, so that each
intervening carbon number and any other stated or intervening
carbon number value in that stated range, is encompassed, it being
further understood that sub-ranges of carbon number within
specified carbon number ranges may independently be included in
smaller carbon number ranges, within the scope of the invention,
and that ranges of carbon numbers specifically excluding a carbon
number or numbers are included in the invention, and sub-ranges
excluding either or both of carbon number limits of specified
ranges are also included in the invention. Accordingly,
C.sub.1-C.sub.12 alkyl is intended to include methyl, ethyl,
propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl
and dodecyl, including straight chain as well as branched groups of
such types. It therefore is to be appreciated that identification
of a carbon number range, e.g., C.sub.1-C.sub.12, as broadly
applicable to a substituent moiety, enables, in specific
embodiments of the invention, the carbon number range to be further
restricted, as a sub-group of moieties having a carbon number range
within the broader specification of the substituent moiety. By way
of example, the carbon number range e.g., C.sub.1-C.sub.12 alkyl,
may be more restrictively specified, in particular embodiments of
the invention, to encompass sub-ranges such as C.sub.1-C.sub.4
alkyl, C.sub.2-C.sub.5 alkyl, C.sub.2-C.sub.4 alkyl,
C.sub.3-C.sub.5 alkyl, or any other sub-range within the broad
carbon number range. In other words, a carbon number range is
deemed to affirmatively set forth each of the carbon number species
in the range, as to the substituent, moiety, or compound to which
such range applies, as a selection group from which specific ones
of the members of the selection group may be selected, either as a
sequential carbon number sub-range, or as specific carbon number
species within such selection group.
[0097] The same construction and selection flexibility is
applicable to stoichiometric coefficients and numerical values
specifying the number of atoms, functional groups, ions or
moieties, as to specified ranges, numerical value constraints
(e.g., inequalities, greater than, less than constraints), as well
as oxidation states and other variables determinative of the
specific form, charge state, and composition applicable to dopant
sources, implantation species, and chemical entities within the
broad scope of the present disclosure.
[0098] "Alkyls" as used herein include, but are not limited to,
methyl, ethyl, propyl, isopropyl, butyl, s-butyl, t-butyl, pentyl
and isopentyl and the like. "Aryls" as used herein includes
hydrocarbons derived from benzene or a benzene derivative that are
unsaturated aromatic carbocyclic groups of from 6 to 10 carbon
atoms. The aryls may have a single or multiple rings. The term
"aryl" as used herein also includes substituted aryls. Examples
include, but are not limited to phenyl, naphthyl, xylene,
phenylethane, substituted phenyl, substituted naphthyl, substituted
xylene, substituted phenylethane and the like. "Cycloalkyls" as
used herein include, but are not limited to cyclopropyl,
cyclobutyl, cyclopentyl, cyclohexyl and the like. In all chemical
formulae herein, a range of carbon numbers will be regarded as
specifying a sequence of consecutive alternative carbon-containing
moieties, including all moieties containing numbers of carbon atoms
intermediate the endpoint values of carbon number in the specific
range as well as moieties containing numbers of carbon atoms equal
to an endpoint value of the specific range, e.g., C.sub.1-C.sub.6,
is inclusive of C.sub.1, C.sub.2, C.sub.3, C.sub.4, C.sub.5 and
C.sub.6, and each of such broader ranges may be further limitingly
specified with reference to carbon numbers within such ranges, as
sub-ranges thereof. Thus, for example, the range C.sub.1-C.sub.6
would be inclusive of and can be further limited by specification
of sub-ranges such as C.sub.1-C.sub.3, C.sub.1-C.sub.4,
C.sub.2-C.sub.6, C.sub.4-C.sub.6, etc. within the scope of the
broader range.
[0099] The disclosure relates in one aspect to a structure,
material, or apparatus comprising metal surface susceptible to
formation of oxide, nitride, or halide (fluoride, chloride, iodide,
and/or bromide) of such metal thereon, the metal surface configured
to be contacted in use or operation of such structure, material, or
apparatus with gas, solid, or liquid that is reactive with said
metal oxide, nitride, or halide to form a reaction product that is
deleterious to the structure, material, or apparatus and its use or
operation, wherein the metal surface is coated with a protective
coating preventing reaction of the coated surface with the reactive
gas.
[0100] In one aspect, the disclosure relates to a semiconductor
manufacturing apparatus comprising metal surface susceptible to
formation of oxide, nitride, or halide of said metal thereon, the
metal surface configured to be contacted in use or operation of
said apparatus with gas, solid, or liquid that is reactive with
said metal to form a reaction product that is deleterious to said
apparatus and its use or operation, wherein the metal surface is
coated with a protective coating preventing reaction of the coated
surface with the reactive gas.
[0101] In such semiconductor manufacturing apparatus, the metal
oxide may in various embodiments comprise at least one oxide of one
or more of Cr, Fe, Co, and Ni, or in other embodiments the metal
oxide may comprise at least one oxide of one or more of Cr, Fe, and
Ni. Metal nitrides may for example form from iron or cobalt in the
presence of ammonia during processing when ammonia is present, with
the resulting iron nitride or cobalt nitride subsequently reacting
with AlCl.sub.3 or TiCl.sub.4. Metal halides may form on the metal
surface during and etch operation or a cleaning cycle operation.
The metal surface in various embodiments may comprise stainless
steel surface. In specific embodiments, the gas that is reactive
with the metal oxide, nitride, or halide to form a reaction product
that is deleterious to the apparatus and its use or operation,
comprises Al.sub.2Cl.sub.6.
[0102] The protective coating in specific applications may comprise
one or more of coating materials selected from the group consisting
of Al.sub.2O.sub.3, oxides of the formula MO, wherein M is Ca, Mg,
or Be; oxides of the formula M'O.sub.2, wherein M' is a
stoichiometrically acceptable metal; and oxides of the formula
Ln.sub.2O.sub.3, wherein Ln is a lanthanide element, e.g., La, Sc,
or Y. More generally, the protective coating may comprise a metal
oxide for which the free energy of reaction with the material that
is contacted with the metal surface in the operation of the
apparatus, is greater than or equal to zero.
[0103] A further aspect of the disclosure relates to a method of
improving performance of a structure, material, or apparatus
comprising metal surface susceptible to formation of oxide,
nitride, or halide of such metal thereon, wherein the metal surface
is configured to be contacted in use or operation of said
structure, material, or apparatus with gas, solid, or liquid that
is reactive with said metal oxide, nitride, or halide to form a
reaction product that is deleterious to said structure, material,
or apparatus and its use or operation, such method comprising
coating the metal surface with a protective coating preventing
reaction of the coated surface with the reactive gas.
[0104] In another aspect, the disclosure relates to a method of
improving performance of a semiconductor manufacturing apparatus
comprising metal surface susceptible to formation of oxide,
nitride, or halide of said metal thereon, wherein the metal surface
is configured to be contacted in use or operation of said apparatus
with gas that is reactive with such metal oxide, nitride, or halide
to form a reaction product that is deleterious to said apparatus
and its use or operation, such method comprising coating the metal
surface with a protective coating preventing reaction of the coated
surface with the reactive gas.
[0105] The metal oxide, nitride, or halide in various embodiments
may comprise at least one oxide, nitride, or halide of one or more
of Cr, Fe, Co, and Ni, and may comprise in other embodiments at
least one oxide, nitride, or halide of one or more of Cr, Fe, and
Ni, or any other suitable metal oxide, nitride, or halide species.
The metal surface may for example comprise stainless steel. The gas
that is reactive with the metal oxide, nitride, or halide to form a
reaction product that is deleterious to the structure, material, or
apparatus and its use or operation, may comprise
Al.sub.2Cl.sub.6.
[0106] The protective coating that is applied to the metal surface
in the aforementioned method may comprise one or more of coating
materials selected from the group consisting of Al.sub.2O.sub.3,
oxides of the formula MO, wherein M is Ca, Mg, or Be; oxides of the
formula M'O.sub.2, wherein M' is a stoichiometrically acceptable
metal; and oxides of the formula Ln.sub.2O.sub.3, wherein Ln is a
lanthanide element, e.g., La, Sc, or Y. More generally, the
protective coating may comprise a metal oxide for which the free
energy of reaction with the gas that is contacted with the metal
surface in the use or operation of said structure, material, or
apparatus, is greater than or equal to zero.
[0107] The protective coating may be applied to the metal surface
in the method of the present disclosure by any suitable technique,
and in specific applications, the coating operation may comprise
physical vapor deposition (PVD), chemical vapor deposition (CVD),
solution deposition, or atomic layer deposition (ALD) of the
protective coating.
[0108] ALD is a preferred technique for application of the
protective coating to the metal surface. In specific applications,
plasma-enhanced ALD may be utilized as the ALD process for forming
the protective coating on the metal surface. In various ALD
embodiments, the protective coating may comprise Al.sub.2O.sub.3.
Such protective coating may for example be applied by atomic layer
deposition comprising a process sequence in which trimethylaluminum
and ozone are utilized in a cyclic ALD process to form the
protective coating, or alternatively, by atomic layer deposition
comprising a process sequence in which trimethylaluminum and water
are utilized in a cyclic ALD process to form the protective
coating.
[0109] In other ALD implementations of the method, the protective
coating may comprise a metal oxide of the formula MO, wherein M is
Ca, Mg, or Be. For its application, the atomic layer deposition may
comprise a process sequence in which a cyclopentadienyl M compound
and ozone are utilized in a cyclic ALD process to form the
protective coating, or a process sequence in which a
cyclopentadienyl M compound and water are utilized in a cyclic ALD
process to form the protective coating, or a process sequence in
which an M beta-diketonate compound and ozone are utilized in a
cyclic ALD process to form the protective coating, or other
suitable process sequence and metal oxide precursor compound. A
wide variety of precursor ligands may be employed for deposition of
the protective coating, including, without limitation, H,
C.sub.1-C.sub.10 alkyl, linear, branched, or cyclic, saturated or
unsaturated; aromatic, heterocyclic, alkoxy, cycloalkyl, silyl,
silylalkyl, silylamide, trimethylsilyl silyl-substituted alkyl,
trialkylsilyl-substituted alkynes, and
trialkylsilylamido-substituted alkynes, dialkylamide, ethylene,
acetylene, alkynes, substituted alkenes, substituted alkynes,
diene, cyclopentadienyls allenes, amines, alkyl amines or bidentate
amines, ammonia, RNH.sub.2 (wherein R is an organo, e.g.,
hydrocarbyl, substituent), amidinates, guanidinates, diazadiene
cyclopentadienyls, oximes, hydroxyamines, acetates,
beta-diketonates, beta-ketoiminates, nitriles, nitrates, sulfates,
phosphates, halo; hydroxyl, substituted hydroxyl, and combinations
and derivatives thereof.
[0110] In still other ALD implementations of the method of applying
the protective coating to the metal surface, the protective coating
may comprise a metal oxide of the formula Ln.sub.2O.sub.3, wherein
Ln is a lanthanide element. Ln may for example be La, Sc, or Y. In
applying the lanthanide oxide protective coating, the atomic layer
deposition may comprise a process sequence in which a
cyclopentadienyl Ln compound and ozone are utilized in a cyclic ALD
process to form the protective coating, or a process sequence in
which a cyclopentadienyl Ln compound and water are utilized in a
cyclic ALD process to form the protective coating, or a process
sequence in which an Ln beta-diketonate compound and ozone are
utilized in a cyclic ALD process to form the protective coating, or
other suitable process sequence and lanthanide precursor
compound.
[0111] The protective coating may be coated on the metal surface at
any suitable thickness, e.g., a coating thickness in a range of
from 5 nm to 5 .mu.m.
[0112] In various embodiments, the metal surface may be at
temperature in a range of from 25.degree. C. to 400.degree. C.
during coating of the metal surface with the protective coating. In
other embodiments, such metal surface may be at temperature in a
range of from 150.degree. C. to 350.degree. C. during the coating
operation. In still other embodiments, the temperature of the metal
surface may be in other ranges, for application of protective
coating thereto.
[0113] The problem addressed by the present disclosure of chemical
attack and transport of contaminant species in semiconductor
manufacturing operations, is particularly acute in stainless steel
furnaces in which wafers are processed for manufacture of
microelectronic devices and other semiconductor manufacturing
products. In such furnaces, the flow of dialuminum hexachloride
vapor has been found to transport measurable levels of Cr, Fe, and
Ni to wafers when Al.sub.2Cl.sub.6 vapor is moved through the
system. Current levels measured are consistent with the removal of
corresponding oxides of such metals that are left on the surface of
the stainless steel, e.g., 316L stainless steel, by either native
oxidation or by electro-polishing.
[0114] The present disclosure addresses this problem by coating
surfaces and components of the furnace with a coating of a material
that will not react with Al.sub.2Cl.sub.6. This achieves a solution
that is far preferable to approaches for removing surface oxides,
nitrides, and halides from stainless steel surfaces and components
so that they do not react with Al.sub.2Cl.sub.6, since there will
always be low levels of ambient moisture leakage or maintenance
events that will expose such surfaces and components to moisture
and oxygen, nitrogen, and halogens. Further, if Al.sub.2Cl.sub.6
were to be flowed in large volumes through the furnace to
reactively remove the metal oxides, nitrides, and halides, such
approach would severely degrade tool throughput and is not a viable
solution.
[0115] The present disclosure contrariwise employs a coating of the
surfaces and components in the furnace or other semiconductor
manufacturing equipment, so that the surfaces and components are
passivated and do not react with the Al.sub.2Cl.sub.6. As
discussed, the coating advantageously comprises one or more of
coating materials selected from the group consisting of:
Al.sub.2O.sub.3, oxides of the formula MO, wherein M is Ca, Mg, or
Be; oxides of the formula M'O.sub.2, wherein M' is a
stoichiometrically acceptable metal, and oxides of the formula
Ln.sub.2O.sub.3, wherein Ln is a lanthanide element, e.g., La, Sc,
or Y.
[0116] The coating can be applied in any suitable manner that
produces a continuous conformal coating on the surfaces and
components of the semiconductor manufacturing equipment, including
techniques of physical vapor deposition (PVD), chemical vapor
deposition (CVD), solution deposition, and atomic layer deposition
(ALD).
[0117] ALD deposition is particularly advantageous for coating
filter elements and the inside of tubes. Trimethylaluminum/ozone
(TMA/O.sub.3) or trimethylaluminum/water (TMA/H.sub.2O) is useful
compositions for depositing Al.sub.2O.sub.3. Cyclopentadienyl
compounds of the metal M or of Ln can be utilized to deposit MO or
Ln.sub.2O.sub.3 in cyclic ALD processes utilizing ozone (O.sub.3)
or water vapor (H.sub.2O). Beta-diketonates of M or Ln can be
utilized to deposit MO or Ln.sub.2O.sub.3 in a cyclic ALD process
in which reactive pulses of the beta-diketonate metal precursor
alternate with pulses of O.sub.3.
[0118] For deposition of an aluminum oxide protective coating, a
precursor for the metal, e.g., trimethylaluminum is selected
together with an oxic component, such as ozone or water, and the
coating conditions are identified, which may illustratively
comprise an ALD sequence of TMA/purge/H.sub.2O/purge or a sequence
of TMA/purge/O.sub.3/purge, with a substrate temperature that may
for example be in a range of from 150.degree. C. to 350.degree. C.,
and a coating thickness in a range of from 5 nm to 5 .mu.m. The
pulse and purge times for the process sequence can then be
determined for a particular reactor and the geometry of the surface
or component that is being coated.
[0119] As a general approach, suitable metal oxides for protecting
surfaces from dialuminum hexachloride, and suitable metal oxides
for protection of surfaces from metal halide vapor can be selected
based on the following methodology.
[0120] The temperature at which dialuminum hexachloride exposure
will occur in the semiconductor equipment is first specified, and
then the chemical reactions are identified for the metals of the
surfaces and components of the semiconductor manufacturing
equipment with the chemical reagents that will be contacting such
surfaces and components. For these chemical reactions at the
specified temperature, the enthalpy and entropy changes, as well as
the free energy and reaction constant, can be identified, as shown
for example in Table 1 below.
TABLE-US-00001 TABLE 1 T .DELTA.H (kJ) .DELTA.S (J/K) .DELTA.G (kJ)
K 2 Cr.sub.(s) + Al.sub.2Cl.sub.6(g) -> 2 CrCl.sub.3(s) +
Al.sub.(s) 120.degree. C. 185 -207 267 10 - 36 Cr.sub.2O.sub.3(s) +
Al.sub.2Cl.sub.6(g) -> 2 CrCl.sub.3(s) + Al.sub.2O.sub.3(s)
120.degree. C. -354 -256 -253 10 + 33 Al.sub.2O.sub.3(s) +
Al.sub.2Cl.sub.6(g) -> 2AlCl.sub.3(s) + Al.sub.2O.sub.3(s)
3CaO.sub.(s) + Al.sub.2Cl.sub.6(g) -> 3CaCl.sub.2(s) +
Al.sub.2O.sub.3(s) 100.degree. C. -860 -206 -784 5.0E+109
3MgO.sub.(s) + Al.sub.2Cl.sub.6(g) -> 3MgCl.sub.2(s) +
Al.sub.2O.sub.3(s) 100.degree. C. -497 -226 -413 6.5E+57
3BeO.sub.(s) + Al.sub.2Cl.sub.6(g) -> 3BeCl.sub.2(s) +
Al.sub.2O.sub.3(s) 100.degree. C. -38.0 -226 46.4 3.2E-7
La.sub.2O.sub.3(s) + Al.sub.2Cl.sub.6(g) -> 2LaCl.sub.3(s) +
Al.sub.2O.sub.3(s) 100.degree. C. -727 -269 -627 5.4E+87
Sc.sub.2O.sub.3(s) + Al.sub.2Cl.sub.6(g) -> 2ScCl.sub.3(s) +
Al.sub.2O.sub.3(s) 100.degree. C. -320 -239 -231 2.4E+32
Y.sub.2O.sub.3(s) + Al.sub.2Cl.sub.6(g) -> 2YCl.sub.3(s) +
Al.sub.2O.sub.3(s) 100.degree. C. -474 -243 -384 4.9E+53
2TiN.sub.(s) + Al.sub.2Cl.sub.6(g) -> 2TiCl.sub.3(s) +
2AlN.sub.(s) 100.degree. C. -106 -207 -29 1.2E+4 2Au(s) + Al2Cl6(g)
= 2AuCl3(s) + 2Al(s) 100.degree. C. 1062 -170 1125 2.5E-158 6Ag(s)
+ Al2Cl6(g) = 6AgCl(s) + 2Al(s) 100.degree. C. 537 -80 567 3.7E-80
Al2O3(s) + 6HBr(g) = 2AlBr3(g) + 3H2O(g) 100.degree. C. 346 21 229
3.7E-87 Al2O3(s) + 6HCl(g) = Al2Cl6(g) + 3H2O(g) 100.degree. C. 208
-135 259 5.8E-37 2Ni(s) + SiCl4(l) = 2NiCl2(s) + Si(s) 100.degree.
C. 74 -92 108 6.6E-16 Ni(s) + GeF4(g) = NiF2(s) + GeF2(s)
100.degree. C. -124 -169 -61 3.2E+8 Al2O3(s) + 1.5GeF4(g) =
2AlF3(s) + 100.degree. C. -428 -305 -314 8.6E+43 1.5GeO2(s)
Cr2O3(s) + 1.5GeF4(g) = 2CrF3(s) + 100.degree. C. -265 -287 -158
1.3E22 1.5GeO2(s) Au(s) + 1.5GeF4(g) = AuF3(s) + 1.5GeF2(s)
100.degree. C. 452 -250 546 3.2E-77 Cu(s) + GeF4(g) = CuF2(s) +
GeF2(s) 100.degree. C. -9 -1667 55 3.3E-8 Au(s) + 2HF(g) = AuF2(s)
+ H2(g) 100.degree. C. 310 -155 368 3.5E-52 A MO.sub.x/2(s) +
Al.sub.2Cl.sub.6(g) -> A MCl.sub.x(s) + Al.sub.2O.sub.3(s)
120.degree. C. .gtoreq.0 A MO.sub.x/2(s) + NX.sub.y(g) -> A
MX.sub.x(s) + NO.sub.2y(s) 120.degree. C. .gtoreq.0
wherein A is the number of moles, X is a halide, and N is an
arbitrary metal. For example, NX.sub.y could be HfCl.sub.4 or
WCl.sub.6.
[0121] The reaction in the first line of Table 1 will not cause
corrosion of the metal in the semiconductor manufacturing
equipment, because the free energy of the reaction is positive. The
reaction in the second line of Table 1, however, can cause
corrosion. By changing the surface oxide of the stainless steel
semiconductor manufacturing equipment from Cr.sub.2O.sub.3 to
Al.sub.2O.sub.3, the driving force for the reaction goes to zero.
Alternatively, as shown in the third line of Table 1, the
protective oxide can be chosen from any metal oxide MO.sub.x for
which the free energy of the reaction is greater than or equal to
zero (and in which x has any stoichiometrically appropriate value).
Further, as shown in the fourth line of Table 1, if a general metal
halide vapor NX.sub.y is being delivered, such as NF.sub.3, a
protective oxide can be chosen from metal oxides MO.sub.x for which
the free energy of the reaction is greater than or equal to
zero.
[0122] The protective coatings of the present disclosure may be
utilized to protect against corrosive agents such as NF.sub.3,
Al.sub.2Cl.sub.6, HfCl.sub.4, TiCl.sub.4, ZrCl.sub.4, WCl.sub.6,
WCl.sub.5, VCl.sub.4, NbCl.sub.5, TaCl.sub.5, and other metal
chlorides. For example, Al.sub.2O.sub.3 may be utilized as a
protective coating material for these corrosive agents.
Semiconductor materials that may be delivered as gases or vapors,
such as fluorine, chlorine, bromine, hydrogen fluoride, hydrogen
chloride, hydrogen bromide, xenon difluoride, boron trifluoride,
silicon tetrafluoride, germanium tetrafluoride, phosphorus
trifluoride, arsenic trifluoride, boron trichloride, silicon
tetrachloride, ozone, may mediate corrosive behavior, and
Al.sub.2O.sub.3 coatings may be usefully employed to provide a
protective film against such corrosive agents. Titanium
tetrachloride is quite corrosive and would have a positive .DELTA.G
for Y.sub.2O.sub.3.
[0123] In specific embodiments, Al.sub.2O.sub.3 is utilized as a
protective coating material having a positive .DELTA.G for hydrogen
bromide exposure of stainless steel surfaces. In other embodiments,
Al.sub.2O.sub.3 is utilized as a protective coating material having
a positive .DELTA.G for hydrogen chloride exposure of stainless
steel surfaces. In still other embodiments, nickel is utilized as a
protective coating material having a positive .DELTA.G for silicon
tetrachloride exposure of stainless steel surfaces.
[0124] In additional embodiments, protective coatings having a
positive .DELTA.G on stainless steel surfaces in exposure to
germanium tetrafluoride may comprise any of nickel,
Al.sub.2O.sub.3, Cr.sub.2O.sub.3, gold, nitrides such as titanium
nitride (TiN), glasses, and copper. Passivation with germanium
tetrafluoride is effective for stainless steel and nickel due to
the formation of surface Ni--F, Cr--F, and Fe--F species, which can
be considered as NiF.sub.2, CrF.sub.3, or FeF.sub.3 layers
overlying nickel or stainless steel.
[0125] In other embodiments, gold is utilized as a protective
coating material having a positive .DELTA.G for hydrogen fluoride
exposure of stainless steel surfaces.
[0126] In various embodiments, protective coatings for stainless
steel and carbon steel include metals such as nickel and metal
alloys. In other embodiments, protective coatings for such services
may include polymeric materials, such as polytetrafluoroethylene
(PTFE) or PTFE-like materials, including protective coatings of
materials commercially available under the trademarks Teflon.RTM.
and Kalrez.RTM.. Protective coatings may also be employed to avoid
embrittlement of stainless steel caused by exposure to hydride
gases, and such protective coatings may be formed of or otherwise
comprise materials such as aluminum, copper, or gold.
[0127] The reactive agents for which protective coatings are
provided on the surfaces may be of solid, liquid and/or gas form,
and may be in a mixture or a solution including one or more
solvents.
[0128] Concerning .DELTA.G more generally, stability in a range of
10.sup.-4<K<10.sup.+4 can be switched by pressure or
temperature changes, and when K>10.sup.+4 there will be little
corrosion under any conditions.
[0129] The dense, pin-hole free coatings of the present disclosure,
as formed by ALD or other vapor phase deposition techniques, are
distinguishable from native oxide surfaces. Native oxide films
typically form at or near room temperature, are crystalline, and
the oxidation associated with such native oxide films may be
incomplete. Such native oxide films are more reactive than the
vapor phase deposition coatings, e.g., ALD coatings, of the present
disclosure. The dense, thick, pin-hole free vapor phase deposition
coatings of the present disclosure are amorphous and conformal.
[0130] In the case of alumina coatings on stainless steel, as
formed in accordance with the present disclosure, cleaning or other
pre-treatment steps may be employed before the deposition of the
Al.sub.2O.sub.3 coating. For example, electropolishing or
decreasing treatments may be employed, or a combination of such
treatments, as may be desirable or advantageous in a specific
implementation of the disclosure. Any other suitable cleaning or
pre-treatment steps may additionally, or alternatively, be
utilized.
[0131] In respect of aluminum trichloride, it is noted that
AlCl.sub.3 does not dissolve in solvents, or in oil or grease,
however, oil or grease may be present as a heat transfer agent,
e.g., in a solid delivery vaporizer in which AlCl.sub.3 or other
chemical is provided for volatilization when the vaporizer is
heated, to provide a vapor stream that is dispensed from the
vessel. For example, the AlCl.sub.3 or other chemical to be
delivered may be mixed with a high boiling point, inert oil or
grease to form a paste that then is loaded onto trays or other
support surface in the solid delivery vessel. The oil or grease
then serves as a heat transfer agent, and as a medium to capture
small particles and prevent them from being entrained in the vapor
flow. These captured small particles then are retained in the oil
or grease until they are vaporized and thereby pass out of the heat
transfer agent and ultimately from the vaporizer vessel. In such
manner, the oil or grease may improve heat conductivity and enable
lower delivery temperature of the vaporizer to be achieved.
[0132] Referring now to the drawings, FIG. 1 is a schematic
representation of a deposition furnace 102 of a semiconductor wafer
processing tool 100 according to one aspect of the present
disclosure.
[0133] The furnace 102 defines a heated interior volume 104 in
which is disposed a liner 110 separating the interior volume into
an inner volume 108 within the liner 110, and an exterior volume
106 outside the liner, as shown. A wafer carrier 112 having wafers
114 mounted therein is positioned in the inner volume 108 within
the liner 110 so that the wafers may be contacted with process gas
in the furnace.
[0134] As shown in the FIG. 1 drawing, a first process gas may be
supplied to the inner volume 108 of the furnace from first process
gas source 116 via first process gas feed line 118. In like manner,
a second process gas may be supplied to the inner volume 108 of the
furnace from second process gas source 120 via second process gas
feed line 122. The first and second process gases may be
concurrently or consecutively introduced to the furnace in the
operation of the tool. The first process gas may for example
comprise an organometallic precursor for vapor deposition of the
metal component on a wafer substrate in the wafer carrier 112. The
second process gas may for example comprise a halide cleaning gas.
The gas introduced to the inner volume 108 of the furnace flows
upwardly within the liner and upon flowing out of the upper open
end of the liner 110, flows downwardly in the annular exterior
volume 106. Such gas then flows out of the furnace in discharge
line 124 to the abatement unit 126 in which the effluent gas from
the furnace is treated to remove hazardous components therefrom,
with discharge of treated gas in vent line 128 to further treatment
or other disposition. The abatement unit 126 may comprise wet
and/or dry scrubbers, catalytic oxidation apparatus, or other
suitable abatement equipment.
[0135] In accordance with the present disclosure, the surfaces of
the furnace and liner component are coated with a layer of
Al.sub.2O.sub.3 so that they resist chemical attack from dialuminum
hexachloride that could in turn render the wafers 114 in the
furnace deficient or even useless for their intended purpose.
[0136] FIG. 2 is a schematic representation of a deposition furnace
process system according to another aspect of the disclosure, for
coating wafers using Al.sub.2Cl.sub.6 vapor, utilizing a solid
source delivery vaporizer in the form of an ampoule for vaporizing
AlCl.sub.3 to form the Al.sub.2Cl.sub.6 vapor, wherein the trays
and internal surfaces of the ampoule are coated with
Al.sub.2O.sub.3, as well as all of the valves, tubing and filters
downstream of the ampoule being coated with Al.sub.2O.sub.3.
[0137] As illustrated, the ampoule is provided with a supply of
argon carrier gas from a supply vessel ("Ar"), and the carrier gas
is flowed through the carrier gas feed line containing a mass flow
controller ("MFC") to the ampoule. In the ampoule, the carrier gas
is contacted with the Al.sub.2Cl.sub.6 vapor produced by heating
the ampoule to volatilize the solid AlCl.sub.3 supported on trays
therein, and the volatilized Al.sub.2Cl.sub.6 then is flowed to the
furnace, containing wafers on which aluminum is deposited from the
Al.sub.2Cl.sub.6 vapor. Co-reactant for the deposition may be
introduced to the furnace as shown, by the co-reactant feed line to
the furnace. The fluid flow through the furnace is controlled by
the pump and pressure control valve assembly, to maintain
conditions in the furnace appropriate for the deposition operation
therein.
[0138] As mentioned, the trays and internal surfaces of the ampoule
are coated with Al.sub.2O.sub.3, as are all of the flow circuitry
surfaces and components therein downstream from the ampoule to
prevent attack by the dialuminum hexachloride vapor. The filters in
the flow circuitry may be of a type commercially available under
the trademarks Wafergard.TM. and Gasketgard.TM. from Entegris,
Inc., Billerica, Mass., USA with metal filter elements.
[0139] FIG. 3 is a perspective, partial breakaway view of a
vaporizer ampoule of a type suitable for use in the deposition
furnace process system of FIG. 2. The vaporizer ampoule includes a
container 300 having holders to help promote contact of a gas with
vapor from material supported by the holders. The container has a
plurality of holders 310, 320, 330, 340, 350, and 360 defining
respective support surfaces 311, 321, 331, 341, 351, and 361. The
container has a bottom wall having a surface 301 and a sidewall 302
to help define a generally cylindrical interior region in container
300 with a generally circular opening at or near the top of
container 300. The inner diameter of the generally cylindrical
interior region in a specific embodiment may be in the range of,
for example, approximately 3 inches to approximately 6 inches.
[0140] Although container 300 is illustrated in FIG. 3 as having an
integral body, the container may be formed from separate pieces.
The container this provides an ampoule for vaporizing material for
delivery to processing equipment.
[0141] As illustrated in FIG. 3, holder 310 may be positioned over
bottom surface 301 to define support surface 311 over bottom
surface 301, holder 320 may be positioned over holder 310 to define
support surface 321 over support surface 311; holder 330 may be
positioned over holder 320 to define support surface 331 over
support surface 321; holder 340 may be positioned over holder 330
to define support surface 341 over support surface 331; holder 350
may be positioned over holder 340 to define support surface 351
over support surface 341; and holder 360 may be positioned over
holder 350 to define support surface 361 over support surface 351.
Although illustrated in FIG. 3 as using six holders 310, 320, 330,
340, 350, and 360, any suitable number of holders may be employed
in various embodiments of the vaporizer.
[0142] As illustrated in FIG. 3, a generally annular support 304
may be placed on bottom surface 301 in the interior region of
container 300 to support holder 310 above bottom surface 301. A
tube 305 may then extend through openings in holders 360, 350, 340,
330, 320, and 310 in a generally central portion of the interior
region of container 300 to a location between holder 310 and bottom
surface 301.
[0143] As one example, the vaporizer of FIG. 3 may be modified by
coupling a baffle or diffuser at the end of tube 305 to help direct
gas flow over material supported on bottom surface 301. In
embodiments in which gas is introduced at or near a lowermost
holder supporting material to be vaporized, introduced gas may be
directed to flow over and/or through material supported by the
lowermost holder using any suitable structure.
[0144] As illustrated in FIG. 3, container 300 may have a collar
around the opening at the top of container 300, and a lid 306 may
be positioned over the collar and secured to the collar using
screws, such as screw 307 for example. A groove may optionally be
defined around the opening at the top of the collar to help
position an O-ring 308 between container 300 and lid 306. O-ring
308 may be formed from any suitable material such as, for example,
Teflon.RTM., any suitable elastomer, or any suitable metal, such as
stainless steel for example. Lid 306 may define through a generally
central region of lid 306 an opening through which a passage or
inlet defined at least in part by tube 305 may extend into the
interior region of container 300. As lid 306 is secured to the
collar for container 300, lid 306 may press against O-ring 308 to
help seal lid 306 over the collar and may press against a collar
around tube 305 to help press lid 306 against holders 360, 350,
340, 330, 320, and 310. An O-ring for holders 360, 350, 340, 330,
320, and 310 may then be compressed to help seal holders 360, 350,
340, 330, 320, and 310 against one another and/or against tube 305.
A valve 381 having an inlet coupling 391 may be coupled to tube 305
to help regulate the introduction of gas into container 300. Lid
306 may also define an opening through which a passage or outlet
defined at least in part by a tube may extend into container 300. A
valve 382 having an outlet coupling 392 may be coupled to the tube
to help regulate the delivery of gas from the container.
[0145] As illustrated in FIG. 3, a generally circular frit 370 may
be positioned over top holder 360 to help filter solid material
from gas flow directed over material supported by holder 360 prior
to delivery through the outlet defined through lid 306. Frit 370
may define through a generally central region of frit 370 a
generally circular opening through which tube 305 may extend. Frit
370 may be pressed over holder 360 in any suitable manner using any
suitable structure as lid 306 is secured to container 300 to help
seal frit 370 over holder 360. The vaporizer may comprise in
addition to or in lieu of frit 370 a frit positioned in the passage
or outlet for gas delivery from container 300 and/or one or more
frits positioned in one or more passageways through one or more of
holders 310, 320, 330, 340, 350, and 360. The frit(s) in the
vaporizer may additionally be coated with Al.sub.2O.sub.3. In like
manner, any other internal components in the vaporizer may be
coated with Al.sub.2O.sub.3, so that all surfaces and components in
the interior volume of the vaporizer are coated with
Al.sub.2O.sub.3.
[0146] In the FIG. 3 vaporizer, a bypass passage defined by tubing
395 coupled between valves 381 and 382 may be used to help purge
valves 381 and 382, inlet coupling 391, and/or outlet coupling 392.
A valve 383 may optionally be coupled to tubing 395 to help
regulate fluid flow through the bypass passage. An inlet/outlet
coupling 397 may optionally be used to help define an additional
inlet/outlet for the interior region of container 300 to help purge
the interior region.
[0147] FIG. 4 is a micrograph, at 15K magnification, of the surface
of a porous metal frit of a type usefully employed in filter
elements, according to another aspect of the disclosure.
[0148] The high surface area of the frit can be advantageously
coated by ALD, wherein metal precursor and oxidizing co-reactant
reach the surface in separate, self-limiting pulses. To coat the
frit with Al.sub.2O.sub.3 alternating pulses of trimethylaluminum
and water or O.sub.3/O.sub.2 mixtures may be employed. Specific
conditions can be empirically determined by increasing the pulse
lengths of each step until all surfaces are coated. Deposition
temperatures from 100-400.degree. C. may be employed to deposit
useful films in specific embodiments.
[0149] It will be appreciated that other aluminum sources may be
employed in the broad practice of the present disclosure, as for
example AlCl.sub.3, other AlR.sub.3 (alkyl) compounds wherein
R.sub.3 is an organo moiety, or other volatile Al compounds. Other
oxygen sources such as N.sub.2O, O.sub.2, alcohols, peroxides, etc.
can also be used with the aluminum source reagents to deposit
Al.sub.2O.sub.3 or related AlO.sub.x materials, in such practice of
the present disclosure.
[0150] The features and advantages of the present disclosure are
more fully shown by the following examples, which are of
illustrative character to facilitate understanding of the
disclosure.
Example 1
[0151] Electropolished 316L stainless steel samples were rinsed
with isopropanol to clean the surface. Two samples were coated with
Al.sub.2O.sub.3 by atomic layer deposition (ALD). One sample was
subjected to 100 ALD cycles of trimethylaluminum/purge/water/purge
and the other sample was subjected to 1000 cycles of the same ALD
process. The deposition temperature was 150.degree. C. Two samples
were not coated. Both coated samples and one of the uncoated
samples were loaded into a glass ampoule with solid AlCl.sub.3
powder in a nitrogen-purged glovebox to prevent moisture or oxygen
from interacting with the samples or with the AlCl.sub.3. The glass
ampoule was then sealed with a PTFE cap. The ampoule with
AlCl.sub.3 and stainless steel samples was heated to 120.degree. C.
for 10 days. At the end of 10 days, the ampoule was cooled and
brought back into the glovebox. The samples were removed from the
AlCl.sub.3 under this inert environment. The mass gain of the
samples was 0.4 to 0.7 mg (<0.15%). All of the surfaces looked
pristine to the eye. Next, these three samples and an additional
sample that had not seen any exposure to AlCl.sub.3 were examined
in the scanning electron microscope (SEM) on their top surfaces and
then cross-sectioned by focused ion beam (FIB) to determine whether
there was any attack of the surface.
[0152] FIG. 5 shows the surface images of a sample that did not see
any AlCl.sub.3. The surface of this sample is clean and shows the
major elements of the stainless steel: Fe, Cr, and Ni.
[0153] FIG. 6 shows the uncoated sample that was exposed to
AlCl.sub.3. It can be seen that there is significant surface
residue on this sample with the addition of Al and Cl to the major
components of the stainless steel.
[0154] FIG. 7 shows a cross-section of the sample that was not
exposed to AlCl.sub.3. It is clear that there is no surface
attack.
[0155] FIG. 8 shows the uncoated sample that was exposed to
AlCl.sub.3. There is a line to compare to the surface so that it is
clear that there was surface attack of 0.1 to 0.2 microns
underneath the area that had Al- and Cl-containing residue.
[0156] FIG. 9 shows a different area of the sample that was exposed
to AlCl.sub.3 with no surface coating. Native oxide is present on
the untreated stainless steel surface. In this area, multiple pits
are clearly visible.
[0157] In contrast, FIG. 10 shows the cross-section of the surface
that had a coating of 100 cycles of TMA/H.sub.2O prior to exposure
to AlCl.sub.3 at 120.degree. C. In this case there is still Al- and
Cl-containing residue adhered to the surface, but there is no
evidence of any attack of the surface of the stainless steel.
[0158] Likewise, FIG. 11 shows the cross-section of the surface
that had a coating of 1000 cycles of TMA/H.sub.2O prior to exposure
to AlCl.sub.3 at 120.degree. C. In this case there is still Al- and
Cl-containing residue adhered to the surface, but there is no
evidence of any attack of the surface of the stainless steel.
Example 2
[0159] In a specific empirical assessment, the efficacy of alumina
coatings was evaluated, in exposure to aluminum trichloride
(AlCl.sub.3) in a first test, and in exposure to tungsten
pentachloride (WCl.sub.5) in a second test.
[0160] In the first test, sample coupons of electropolished 316L
stainless steel were either coated with 470 .ANG. of
Al.sub.2O.sub.3 or uncoated. One sample of each type was placed in
one of two containers with solid AlCl.sub.3. Both of the containers
were loaded, sealed, and pressurized to 3 psig with helium inside
of a N.sub.2 purged glovebox, with O.sub.2 and H.sub.2O levels
below 0.1 ppm. Outboard He leak tests determined that one of the
containers had a leak rate below 1E-6 standard cubic centimeter per
second (scc/s), which was the resolution limit of the measurement,
and the other container had a leak rate of 2.5E-6 scc/s. The
containers were heated in the same oven to 155.degree. C. for nine
days, cooled, and the coupons were removed in the glovebox. Table 2
shows the mass changes of the various coupons.
TABLE-US-00002 TABLE 2 Mass Changes of various coupons soaked in
AlCl.sub.3 for 9 days at 155.degree. C. leak initial post rate mass
mass change % sample type ID scc He/s g g g change coated coupon 2
2.50E-06 3.3986 3.3967 -0.0019 -0.06% coated coupon 3 <1E-6
3.3896 3.3896 0.0000 0.00% uncoated coupon 12 2.50E-06 3.3913
3.3824 -0.0089 -0.26% uncoated coupon 13 <1E-6 3.4554 3.4554
0.0000 0.00%
[0161] FIG. 12 is a composite photograph of the sample coupons of
Table 2 after the nine-day exposure to AlCl.sub.3 at 155.degree.
C., in which the respective coupons are identified by the same ID
numbers as are set out in Table 2.
[0162] From Table 2 it is evident that the mass changes were only
quantifiable when there was a measurable leak of the container. In
this corrosive exposure, the loss of mass of the samples as
tabulated in Table 2 and the composite photograph of the respective
sample coupons in FIG. 12 show that the coated sample coupon 2 was
in substantially better condition than the uncoated sample coupon
12 after the nine-day exposure to ACl.sub.3 at 155.degree. C. There
was no change in the Al.sub.2O.sub.3 coating thickness as measured
by XRF.
[0163] In the second test, sample coupons of electropolished 316L
stainless steel were either coated with 470 .ANG. thick coatings of
Al.sub.2O.sub.3 or were uncoated. Sample coupons were placed in
containers with solid WCl.sub.5, with 165.degree. C., 180.degree.
C. and 220.degree. C. temperature conditions being maintained in
respective containers. All of the containers were loaded and sealed
inside of a N.sub.2 purged glovebox, with O.sub.2 and H.sub.2O
levels below 0.1 ppm. The containers then were heated in an oven
for ten days, cooled, and the sample coupons were removed from the
respective containers, in the glovebox.
[0164] Thickness measurements were made by x-ray fluorescence (XRF)
spectroscopy technique, to assess change in coating thickness of
the alumina coating, from initial measured thickness. Table 3
contains the XRF measurements of Al.sub.2O.sub.3 thickness before
and after exposure to WCl.sub.5, for two sample coupons maintained
at 165.degree. C. for 10 days in such exposure, for two sample
coupons maintained at 180.degree. C. for 10 days in such exposure,
and for one sample coupon maintained at 220.degree. C. for 10 days
in such exposure. Approximately 15-30 .ANG. of the coating was
typically etched away in the cleaning process.
TABLE-US-00003 TABLE 3 XRF measurements of Al.sub.2O.sub.3 film
thickness before and after exposure to WCl.sub.5 at various
temperatures for 10 days. Final Change T .degree. C. Initial AlOx
thickness, .ANG. AlOx thickness, .ANG. in thickness, .ANG. 165
462.4 439.6 -22.8 165 467.5 450.8 -16.7 180 474.8 447.8 -27.0 180
477.5 411.7 -65.8 220 476.1 182.8 -293.4
[0165] FIG. 13 is a top-down scanning electron microscope (SEM)
micrograph of the sample exposed to WCl.sub.5 at 220.degree. C. for
10 days, and FIG. 14 is a focused ion beam (FIB) cross-section of
the edge of the coating in such sample.
[0166] Coated and uncoated samples in this second test showed no
sign of corrosion visually or by SEM examination or by weight
change. However, at the higher temperature, a significant amount of
the Al.sub.2O.sub.3 coating was removed. Both samples at
165.degree. C. were etched in an amount consistent with the
cleaning process. One of the samples at 180.degree. C. lost 27
.ANG. of thickness, consistent with cleaning, but the other sample
lost approximately 66 .ANG. of thickness, which is significantly
above that of cleaning. At 220.degree. C., about 60% of the coating
was removed, as shown in FIG. 13 in which the alumina coating is
removed in some areas (lighter area portion) and is intact in
others (darker area portion). In FIG. 14, the micrograph shows the
coating intact to the right, and the edge of the coated area is
indicated by the arrow.
[0167] It will be recognized that although the disclosure is
directed illustratively to semiconductor manufacturing equipment,
the protective coating approach of the present disclosure is
likewise applicable to other gas processing apparatus for the
manufacture of other products, such as flat-panel displays,
photovoltaic cells, solar panels, etc. where surfaces in the
process equipment are susceptible to attack by vapor phase
components that react with oxides on such services to form reaction
products that are deleterious to the products made and processes
conducted with such equipment.
[0168] Set out below is a further aspect of the disclosure relating
to thin film atomic layer deposition coatings.
[0169] While various compositions and methods are described, it is
to be understood that this invention is not limited to the
particular molecules, compositions, designs, methodologies or
protocols described, as these may vary. It is also to be understood
that the terminology used in the description is for the purpose of
describing the particular versions or embodiments only, and is not
intended to limit the scope of the present invention.
[0170] It must also be noted that as used herein, the singular
forms "a", "an", and "the" include plural reference unless the
context clearly dictates otherwise. Thus, for example, reference to
a "layer" is a reference to one of more layers and equivalents
thereof known to those skilled in the art, and so forth. Unless
defined otherwise, all technical and scientific terms used herein
have the same meanings as commonly understood by one of ordinary
skill in the art.
[0171] Methods and materials similar or equivalent to those
described herein can be used in the practice or testing of
embodiments of the present disclosure. All publications mentioned
herein are incorporated by reference in their entirety. Nothing
herein is to be construed as an admission that the invention
claimed herein is not entitled to antedate such publications by
virtue of prior invention. "Option" or "optionally" means that the
subsequently described event or circumstance may or may not occur,
and that the description includes instances wherein the event
occurs and instances where it does not. All numeric values herein
can be modified by the term "about," whether or not explicitly
indicated. The term "about" generally refers to a range of numbers
that one of skill in the art would consider equivalent to the
recited value (i.e., having similar function or result). In some
embodiments the term "about" refers to .+-.10% of the stated value,
in other embodiments the term "about" refers to .+-.2% of the
stated value. While compositions and methods are described in terms
of "compromising" various components and steps, such terminology
should be interpreted as defining essentially closed or closed
member groups.
[0172] As used herein, the term "film" refers to a layer of
deposited material having a thickness below 1000 micrometers, e.g.,
from such value down to atomic monolayer thickness values. In
various embodiments, film thicknesses of deposited material layers
in the practice of the invention may for example be below 100, 50,
20, 10, or 1 micrometers, or in various thin film regimes below
200, 100, 50, 20, or 10 nanometers, depending on the specific
application involved. As used herein, the term "thin film" means a
layer of a material having a thickness below 1 micrometer.
[0173] Although the disclosure has been set forth herein with
respect to one or more implementations, equivalent alterations and
modifications will occur to others skilled in the art based upon a
reading and understanding of this specification. The disclosure
includes all such modifications and alterations. In addition, while
a particular feature or aspect of the disclosure may have been
disclosed with respect to only one of several implementations, such
feature or aspect may be combined with one or more other features
or aspects of the other implementations as may be desired and
advantageous for any given or particular application. Furthermore,
to the extent that the terms "includes", "having", "has", "with",
or variants thereof are herein, such terms are intended to be
inclusive in a manner similar to the term "comprising." Also, the
term "exemplary" is merely meant to mean an example, rather than
the best. It is also to be appreciated that features, layers and/or
elements depicted herein are illustrated and/or taught with
particular dimensions and/or orientations relative to one another
for purposes of simplicity and ease of understanding, and that the
actual dimensions and/or orientations may differ substantially from
that illustrated and/or taught herein.
[0174] Thus, the disclosure, as variously set out herein in respect
of features, aspects and embodiments thereof, may in particular
implementations be constituted as comprising, consisting, or
consisting essentially of, some or all of such features, aspects
and embodiments, as well as elements and components thereof being
aggregated to constitute various further implementations of the
disclosure. The disclosure correspondingly contemplates such
features, aspects and embodiments, or a selected one or ones
thereof, in various permutations and combinations, as being within
the scope of the present disclosure. Further, the disclosure
contemplates embodiments that may be defined by exclusion of any
one or more of the specific features, aspects, or elements that are
disclosed herein in connection with other embodiments of the
disclosure.
[0175] In accordance with one aspect of the present disclosure,
there is provided a thin film coating comprised of one of more
layers, where at least one layer is deposited by atomic layer
deposition.
[0176] In accordance with aspects of the disclosure, the following
are provided: [0177] ALD coating with a film thickness of more than
1 .ANG. and in some applications more than 10,000 .ANG. [0178] ALD
coating providing a very dense, pine-hole-free, defect-free layer.
[0179] Thin film coating intended for deposition applications on a
multitude of parts, but not directly for the actual IC device
(transistor) manufacturing on a Si wafer. [0180] ALD coating may be
comprised of insulating metal oxides such as alumina
(Al.sub.2O.sub.3), yttria (Y.sub.2O.sub.3), zirconia (ZrO.sub.2),
titania (TiO.sub.2), etc., and metals such as platinum, niobium, or
nickel. [0181] ALD coating may be deposited between RT (room
temperature) and 400.degree. C. [0182] ALD coating may be a single
film with a defined stoichiometry, such as for example a 1 micron
thick alumina layer, or several layers such as for example {0.25
micron titania+0.5 micron alumina+0.25 micron zirconia} or a true
multilayer structure, such as for example {1 atomic layer titania+2
atomic layers alumina}.times.n, with n being in a range of 1 to
10,000, or combinations thereof. [0183] The thin film coating where
the ALD layer is combined with another layer that is deposited by a
different deposition technique, such as PE-CVD, PVD, spin-on or
sol-gel deposition, atmospheric plasma deposition, or the like.
[0184] Total film thickness between 1 micron and 100 microns.
[0185] Portion of ALD coating thickness of the entire stack to be
less or equal than 2 microns, with the 2 microns being in one or
more distinct layers. [0186] Other coating materials being selected
from the group of oxides, such as alumina, aluminum-oxy nitride,
yttria, yttria-alumina mixes, silicon oxide, silicon oxy-nitride,
transition metal oxides, transition metal oxy-nitrides, rare earth
metal oxides, rare earth metal oxy-nitrides. [0187] Ability to
pattern ALD coating: [0188] Method 1: Uniformly coat part and then
etch back unwanted materials through a mask (the etch back can be
mechanical, e.g., bead blast, physical, e.g., plasma ions, or
chemical, e.g., plasma or wet etch). [0189] Method 2: Mask unwanted
area, ALD coat and then remove masked areas. The mask can be a
sealed sheet, or fixture or photo resist (lift-off technique).
[0190] Method 3: Create pattern on substrate with a surface
termination that blocks the ALD film growth. For example, a surface
termination layer may be employed that has "zero" sticking
coefficient for H.sub.2O and TMA (trimethylaluminum). As used
herein, a surface termination layer is a self-limiting layer, e.g.,
a self-limiting ALD layer. As used herein, the sticking coefficient
is the ratio of the number of adsorbate atoms (or molecules) that
adsorb, or "stick," to a surface, to the total number of items that
impinge on that surface during the same period of time.
[0191] In accordance with aspects of the disclosure, the following
applications are provided:
[0192] Applications: [0193] Defect-free, pin-hole-free, dense,
electrical insulation of parts. [0194] Ability to coat parts with
high-aspect ratio features. Examples: (1) Parts with deep holes,
channels and 3-dimensional features, (2) hardware such as screws
and nuts, (3) porous membranes, filters, 3-dimensional network
structures, (4) structures with connected pore matrices. [0195]
Electrical insulation layer: High dielectric breakdown strength and
high electrical resistance (low leakage). This is achieved with ALD
Al.sub.2O.sub.3. Using multi-layers of titania-alumina-zirconia
(TAZ) further improve electrical insulator performance. There are
various multilayer-configurations:
[0195] X nm TiO.sub.2+Y nm Al.sub.2O.sub.3+Z nm ZrO.sub.2
[U nm TiO.sub.2+V nm Al.sub.2O.sub.3+W nm ZrO.sub.2T] times n
X nm TiO.sub.2+[V nm Al.sub.2O.sub.3+W nm ZrO.sub.2T] times m
[0196] etc.; wherein X, Y, Z, U, V, and W may each be in a range of
from 0.02 nm to 500 nm, and wherein each of n and m may be in a
range of from 2 to 2000. [0197] Chemical and etch-resistant
coating: The ALD layer can be alumina, yttria, ceria, or similar.
The total etch resistant coating may be comprised of (1) ALD layer
only, (2) combination of PVD, CVD, and ALD, (3) ALD may be overcoat
and serve as sealant layer, as discussed more fully hereinafter,
(4) ALD may be underlayer to provide robust foundation, and (5) ALD
may be interspersed between CVD and/or PVD coating layers. [0198]
The ALD coating may provide chemical resistance for applications
such as advanced batteries, gas filters, liquid filters,
electro-plating tool components, plasma-wetted components (to
protect against fluorine and other halogen attack), etc. [0199] The
ALD coating may serve as corrosion-resistant coating [0200]
Diffusion barrier layer; the ALD layer, which is dense, conformal
and pin-hole free provides excellent trace metal diffusion barrier
characteristics [0201] The ALD layer may serve as an adhesion layer
between an underlying substrate (glass, quartz, aluminum, anodized
aluminum, alumina, stainless steel, silicon, SiOx, AlON, etc.) and
an overlying coating layer (PVD yttria, PVD AlON, PVD
Al.sub.2O.sub.3, CVD SiOx, CVD SiO.sub.xN.sub.y, CVD
Al.sub.2O.sub.3, CVD AlO.sub.xN.sub.y, DLC, Si, SiC, etc.)
[0202] In accordance with another aspect of the disclosure, an
ALD-deposited surface sealant layer is used for coatings. ALD
(atomic layer deposition) is an established technology, which uses
chemical adsorption of two or more alternating precursors to form
very dense, nearly perfectly arranged (physically and
stoichiometrically) thin films. The technique allows for precisely
controlled film growth, is nearly 100% conformal and will grow
films at any surface location that the precursor gas can reach,
including within very high aspect ratio features. In this respect,
an ALD-deposited sealant coating can be used for the following
applications:
[0203] (1) to overcoat and seal an existing surface and therefore
provide enhanced and superior properties of that surface/part
[0204] (2) to apply an ALD sealing coating on top of a CVD, PVD,
spray- or other coating to provide a sealant for the imperfections
of that coating, such as:
[0205] (i) filling any cracks near the coating surface and
therefore providing a surface that is impermeable to corrosive and
etching environments
[0206] (ii) filling and sealing any macropores, coating defects,
intrusions, etc. to provide a coating surface layer that is
impermeable to gases and liquids and terminated with a controlled
smooth, conformal sealant layer
[0207] (iii) reducing surface roughness and overall surface area of
the coating, thus providing a smooth and dense surface layer that
allows for minimal attack in corrosive environments
[0208] (iv) minimizing particle generation, improving hardness,
toughness and scratch resistance by providing a dense and smooth
sealed surface with overcoat
[0209] In various aspects of the disclosure, the ALD sealant may be
applied to parts and surfaces that require:
[0210] (a) improved etch and corrosion resistance, and/or
[0211] (b) reduced friction, wear, and improved mechanical abrasion
resistance
[0212] The ALD sealant layer at the same time may also serve as a
diffusion barrier, and it has the ability to control surface
electrical properties as well as the surface termination, such as
hydrophilicity and hydrophobicity.
[0213] A further aspect of the disclosure involves use of ALD
technology with fibrous metal membranes with chemically resistant
coatings like alumina, yttria, or other coatings of this type. The
ALD technology allows gases to penetrate the porous filter and
coats over the fibrous membrane providing resistance to corrosive
gases.
[0214] This aspect of the disclosure provides a deposition
gas-based technique that can penetrate small micron size openings
and coat uniformly over the fibers.
[0215] This aspect of the disclosure has been demonstrated by
depositing alumina coating on a 4-micron Ni-based gas filter made
by Entegris, Inc. of Billerica, Mass., U.S.A.
[0216] The ALD technology of this disclosure offers many benefits,
such as:
[0217] 1) Coating penetration into small features like micron size
porosity of the filters ensuring complete coverage
[0218] 2) Hermetic sealing of the fibers thus protecting the filter
membranes
[0219] 3) Various different coatings can be deposited used this
technique
[0220] The disclosure also contemplates use of ALD coatings to
improve the processing characteristics of the substrate article or
equipment that is coated. For example, ALD films may be employed to
combat blistering or other undesired phenomena that may occur
during annealing of substrate articles, due to mismatches in
coefficient of thermal expansion between layers of a multilayer
film article. Thus, ALD films may be employed in the multilayer
film structure to ameliorate such material property differences, or
otherwise to improve electrical, chemical, thermal, and other
performance properties of the ultimate product article.
[0221] The disclosure further contemplates the use of ALD coatings
to protect fluid-contacting surfaces of apparatus handling fluids
that may present a risk of chemical attack in the use of such
apparatus. Such apparatus may include for example fluid storage and
dispensing packages employed to supply gas to semiconductor
manufacturing tools, where the fluid may adversely affect the flow
path components and downstream process equipment. Fluids that may
present a specific issue in particular applications may include
halide gases such as fluorides of boron or germanium. Thus, the
coatings of the present disclosure may be employed to enhance the
performance of process equipment, flow circuitry, and system
components, in these and other applications.
[0222] In a further aspect, the disclosure relates to a composite
ALD coating, comprising layers of different ALD product materials.
The different ALD product materials may be of any suitable type,
and may for example comprise different metal oxides, e.g., at least
two metal oxides selected from the group consisting of titania,
alumina, zirconia, oxides of the formula MO wherein M is Ca, Mg, or
Be, oxides of the formula M'O.sub.2, wherein M' is a
stoichiometrically acceptable metal, and oxides of the formula
Ln.sub.2O.sub.3 wherein Ln is a lanthanide element, such as La, Sc,
or Y. In other embodiments, the composite ALD coating may include
at least one layer of alumina. In still other embodiments, the
composite ALD coating may include at least one layer of titania, or
zirconia, or other suitable material.
[0223] Such composite ALD coating may comprise different metals as
the different ALD product materials, e.g., at least two metals
selected from the group consisting of platinum, niobium, and
nickel. Any suitable differing metals can be employed.
[0224] In other embodiments, the different ALD product materials
may comprise a metal oxide material as a first ALD product material
in a first layer of the composite coating and a metal as a second
ALD product material in a second layer of the composite coating.
The metal oxide material may for example be selected from the group
consisting of alumina, titania, and zirconia, and the metal is
selected from the group consisting of platinum, niobium, and
nickel.
[0225] The composite ALD coating described above may have any
suitable number of layers, e.g., from 2 to 10,000 layers in the
coating.
[0226] The disclosure in another aspect relates to a composite
coating, comprising at least one ALD layer and at least one
deposited layer that is not an ALD layer. The composite coating may
for example be constituted, so that the at least one deposited
layer that is not an ALD layer is selected from the group
consisting of CVD layers, PE-CVD layers, PVD layers, spin-on
layers, sprayed layers, sol gel layers, and atmospheric plasma
deposition layers. In various embodiments, the layers in the
composite coating may comprise at least one layer of material
selected from the group consisting of alumina, aluminum-oxy
nitride, yttria, yttria-alumina, silicon oxide, silicon
oxy-nitride, transition metal oxides, transition metal
oxy-nitrides, rare earth metal oxides, and rare earth metal
oxy-nitrides.
[0227] The disclosure further contemplates a method of forming a
patterned ALD coating on a substrate, comprising forming a pattern
on the substrate of a layer of surface termination material that is
effective to prevent ALD film growth. Such surface termination
material in a particular implementation may exhibit an essentially
zero sticking coefficient for water and trimethylaluminum. In
various embodiments, the ALD coating may comprise alumina.
[0228] The disclosure further contemplates a method of filling
and/or sealing surface infirmities of a material, said method
comprising applying an ALD coating on a surface infirmity of the
material, at a thickness effecting filling and/or sealing of the
infirmity. The infirmity may be of any type, and may for example be
selected from the group consisting of cracks, morphological
defects, pores, pinholes, discontinuities, intrusions, surface
roughness, and surface asperities.
[0229] Another aspect of the disclosure relates to a filter,
comprising a matrix of fibers and/or particles, the fibers and/or
particles being formed of metal and/or polymeric material, wherein
the matrix of fibers and/or particles has an ALD coating thereon,
wherein the ALD coating does not alter pore volume of the matrix of
fibers and/or particles by more than 5%, as compared to a
corresponding matrix of fibers and/or particles lacking said ALD
coating thereon, and wherein when the fibers and/or particles are
formed of metal, and the ALD coating comprises metal, the metal of
the ALD coating is different from the metal of the fibers and/or
particles.
[0230] The filter may be constructed with the matrix of fibers
and/or particles in a housing that is configured for flow of fluid
through the matrix for filtration of the fluid. In various
embodiments, the ALD coating may comprise a transition metal, metal
oxide, or transition metal oxide of suitable type. For example, the
ALD coating may comprise a metal oxide selected from the group
consisting of titania, alumina, zirconia, oxides of the formula MO
wherein M is Ca, Mg, or Be, and oxides of the formula
Ln.sub.2O.sub.3 wherein Ln is a lanthanide element, La, Sc, or Y.
The ALD coating in various implementations comprises alumina. The
matrix of the filter may comprise nickel fibers and/or particles,
stainless steel fibers and/or particles, or fibers and/or particles
of other materials such as polymeric materials, e.g.,
polytetrafluoroethylene. The filter may in various embodiments
comprise pores of any suitable diameter. For example, the pores may
be in a range of from 1 .mu.m to 40 .mu.m in some embodiments, and
in other embodiments may be less than 20 .mu.m, less than 10 .mu.m,
less than 5 .mu.m or other suitable value, and in other embodiments
may be in a range of from 1 to 10 .mu.m, 1 to 20 .mu.m, 20 to 40
.mu.m, or other suitable range of values. The ALD coating itself
may be of any suitable thickness, and in various embodiments may
have thickness in a range of from 2 to 500 nm. In general, any
suitable pore size and thickness characteristics may be employed,
as appropriate for a specific end use or application.
[0231] The filter may be of suitable character as regards its
retention rating. For example, the retention rating of the filter
in specific embodiments may be characterized by log reduction value
of 9 (denoted as 9LRV) for particles greater than 3 nm at a gas
flow rate of 30 standard liters per minute gas flow or less.
ALD-coated filters of the present disclosure may be employed in
various applications in which the filter is desired to achieve a
high efficiency rate of removal, as for example a rate of removal
of 99.9999999%, determined at a most penetrating particle size,
i.e., 9LRV, at a specific rated flow. The test methodology for
evaluating 9LRV rating is described in Rubow, K. L., and Davis, C.
B., "Particle Penetration Characteristics of Porous Metal Filter
Media For High Purity Gas Filtration," Proceedings of the 37rd
Annual Technical Meeting of the Institute of Environmental
Sciences, pp. 834-840 (1991); Rubow, K. L., D. S. Prause and M. R.
Eisenmann, "A Low Pressure Drop Sintered Metal Filter for
Ultra-High Purity Gas Systems", Proc. of the 43rd Annual Technical
Meeting of the Institute of Environmental Sciences, (1997); and
Semiconductor Equipment and Materials International (SEMI) test
method SEMI F38-0699 "Test Method for Efficiency Qualification of
Point-of-Use Gas Filters," all of which are incorporated herein by
reference.
[0232] Sintered metal filters/diffusers that may be coated with
protective coatings by ALD in accordance with the present
disclosure include the sintered metal filters/diffusers described
in U.S. Pat. Nos. 5,114,447; 5,487,771; and 8,932,381, and in U.S.
Patent Application Publication 2013/0305673.
[0233] Gas filters coated with protective coatings in accordance
with the present disclosure may be variously configured. In
specific illustrative embodiments, the filters may have a pore size
in a range of from 1 to 40 .mu.m, or in a range of from 1 to 20
.mu.m, or in a range of from 20 to 40 .mu.m, or other suitable
values. Such gas filters may exist in stainless steel and nickel
configurations. Both are susceptible to metals contamination when
exposed to aggressive gas environments. The filter matrix of such
gas filters may be over coated with chemically inert and robust
thin films of alumina using ALD coating techniques in accordance
with the present disclosure. The ALD process may include any number
of depositions cycles, e.g., in a range of from 100 to 5000 cycles.
In a specific implementation, the ALD alumina films may be
deposited with 50 to 1500 cycles, using a
trimethylaluminum/H.sub.2O process with extended wait and purge
times, at temperature that may for example be in a range of
200.degree. C. to 300.degree. C., e.g., 250.degree. C., with
deposition of 0.75 .ANG. to 1.25 .ANG. per cycle, e.g., 1.1
.ANG./cycle.
[0234] The ALD alumina coating process may be carried out to
provide alumina coating thicknesses on the gas filter that may for
example be in a range of from 15 nm to 200 nm in various
embodiments. In other embodiments, the ALD alumina coating
thickness may be in a range of from 20 nm to 50 nm.
[0235] The above-described gas filter coatings as formed by ALD
coating techniques may be carried out to provide varying aluminum
content in aluminum oxide films. For example, the aluminum content
of such films may be in a range of from 25 atomic percent to 40
atomic percent, in various embodiments. In other embodiments, the
aluminum content is in a range of from 28 atomic percent to 35
atomic percent, and in still other embodiments, the aluminum
content of the ALD coating is in a range of from 30 atomic percent
to 32 atomic percent of the aluminum oxide film.
[0236] In other illustrative embodiments, the gas filter may
comprise an in-line metal gas filter having pore size in a range of
from 2 to 5 .mu.m, in which the filter includes a titanium filter
matrix, wherein the ALD alumina coating has a thickness that may be
in a range of from 10 nm to 40 nm, e.g., 20 nm thickness. In still
other embodiments, the gas filter may comprise a nickel-based gas
filter matrix having pore size in a range of from 2 to 5 .mu.m,
wherein the ALD alumina coating has a thickness that may be in a
range of from 10 nm to 40 nm, e.g., 20 nm thickness.
[0237] The protective coatings of the present disclosure may also
be employed for coating of surfaces in chemical reagents supply
packages, such as fluid storage and dispensing vessels, solid
reagent vaporizer vessels, and the like. Such fluid storage and
dispensing vessels may variously contain, in addition to the
material to be stored in and dispensed from such vessels, storage
media for the stored material, from which the stored material may
be disengaged for dispensing of same from the vessel of the
material supply package. Such storage media may include physical
adsorbents on which fluids are reversibly adsorbed, ionic storage
media for reversible fluid storage, and the like. For example,
solid delivery packages of the type disclosed in International
Publication WO2008/028170 published Mar. 6, 2008, the disclosure of
which hereby is incorporated herein by reference in its entirety,
may be coated on interior surface thereof with a protective coating
of the present disclosure.
[0238] Chemical reagents supply packages of other types may be
employed, in which internal surface of a supply vessel is coated
with a protective coating of the present disclosure, such as
internally pressure-regulated fluid supply vessels for delivery of
gases, e.g., gases such as boron trifluoride, germanium
tetrafluoride, silicon tetrafluoride, and other gases utilized in
manufacture of semiconductor products, flat-panel displays, and
solar panels.
[0239] A further aspect of the disclosure relates to a method of
delivering a gaseous or vapor stream to a semiconductor processing
tool, said method comprising providing a flow path for the gaseous
or vapor stream, from a source of said gaseous or vapor stream to
the semiconductor processing tool, and flowing the gaseous or vapor
stream through a filter in the flow path to remove extraneous solid
material from the stream, wherein the filter comprises a filter of
a type as variously described herein.
[0240] In such method, the gaseous or vapor stream may comprise any
suitable fluid species, and in particular embodiments, such stream
comprises dialuminum hexachloride. A specific filter useful for
such fluid applications includes an ALD coating comprising alumina,
wherein the matrix comprises stainless steel fibers and/or
particles.
[0241] The semiconductor processing tool in the aforementioned
method may be of any suitable type, and may for example comprise a
vapor deposition furnace.
[0242] As mentioned above, the filter may be varied in the ALD
coating and matrix. In specific embodiments, the filter comprises a
sintered matrix of stainless steel fibers and/or particles that is
coated with an ALD coating of alumina, wherein the sintered matrix
comprises pores of a diameter in a range of from 1 to 40 .mu.m,
e.g., from 1 to 20 .mu.m, from 1 to 10 .mu.m, from 10 to 20 .mu.m,
or in other suitable range of pore diameter values, and wherein the
ALD coating in any of such embodiments has a thickness in a range
of from 2 to 500 nm.
[0243] The disclosure in another aspect relates to use of ALD for
pore size control in fine filtration applications, to achieve
filters that are specifically tailored, beyond the capabilities
afforded by sintered metal matrix filters alone. In this respect,
control the pore sizes in sintered metal matrix filters becomes
progressively more difficult as the target pore size shrinks to
less than 5 .mu.m. In accordance with the present disclosure, ALD
coatings can be used to effectively shrink the pore size with a
high degree of control of pore size and pore size distribution.
While coatings deposited by ALD may be substantially thicker than
employed in other applications, ALD affords the possibility of
extraordinary control of the pore size and pore size distribution,
while still achieving chemical resistance benefits, e.g., with ALD
coatings of alumina.
[0244] Thus, ALD coating of sintered metal matrix materials may be
applied at substantial thicknesses on the sintered metal matrix
structure, with the coating thickness being of such magnitude as to
reduce pore size in the coated metal matrix structure to very low
levels, e.g., to sub-micron pore size levels.
[0245] Such approach may also be employed to effect the creation of
filters with porosity gradients, such as a porosity gradient from a
gas inlet face to a gas discharge face, wherein relatively larger
sized pores are present at the gas inlet face and relatively
smaller sized pores are present at the gas discharge face of the
filter, with a porosity gradient between the respective faces of
the filter. With such porosity gradient, the filter may for example
be employed to capture large particles at an entrance side of the
filter and smaller particles on the exit side of the filter, so
that an overall highly effective filtration action is achieved.
[0246] The disclosure therefore contemplates filters comprising a
porous material matrix coated with an ALD coating wherein the pore
size of the porous metal matrix has been reduced by the ALD
coating, e.g., by from 5% to 95% reduction in average pore size by
the ALD coating in relation to a corresponding porous material
matrix not coated with the ALD coating.
[0247] The disclosure also contemplates filters comprising a porous
material matrix coated with an ALD coating, wherein the coating
thickness is directionally varied to provide a corresponding pore
size gradient in the filter, e.g., from an inlet phase to an outlet
face of the filter, as above described.
[0248] A further aspect of the disclosure relates to a method of
fabricating a porous filter, comprising coating a porous material
matrix with an ALD coating, to reduce average pore size of the
porous material matrix. The method may be utilized to achieve a
predetermined reduction of average pore size of the porous material
matrix, and/or a directionally varied pore size gradient in the
porous material matrix.
[0249] The porous material matrix in any of the above aspects and
embodiments may comprise a sintered metal matrix, e.g., of
titanium, stainless steel, or other metal matrix material.
[0250] In another aspect, the disclosure relates to a solid
vaporizer apparatus comprising a vessel defining an interior volume
including support surface therein for solid material to be
vaporized, wherein at least a portion of the support surface has an
ALD coating thereon. The support surface may comprise interior
surface of the vessel, such as the vessel wall surface, and/or
floor of the vessel, or extended surface integrally formed with the
wall and/or floor surfaces, so that the support surface comprises
interior surface of the vessel, and/or the support surface may
comprise surface of a support member in the interior volume, such
as a trade providing support surface for the solid material to be
vaporized. The tray may be coated partially or fully with the ALD
coating. In other embodiments, the vessel may contain an array of
vertically spaced apart trays, each providing support surface for
the solid material. Each of such trays in the array may be coated
with the ALD coating.
[0251] The vessel may be fabricated with the interior wall surface
of the vessel that bounds the interior volume thereof being coated
with the ALD coating. The ALD coating may for example comprise
alumina, e.g., with thickness in a range of from 2 to 500 nm. The
support surface coated by the ALD coating in any of the
aforementioned embodiments may be a stainless steel surface. The
vaporizer vessel itself may be formed of stainless steel. The
vaporizer apparatus may be provided in a solids-loaded state,
containing vaporizable solid material on the support surface of the
vessel, e.g., on support surfaces of stacked trays in the interior
volume of the vessel. The vaporizable solid material may be of any
suitable type, and may for example comprise precursor material for
vapor deposition or ion implantation operations. The vaporizable
solid material may comprise an organometallic compound, or a metal
halide compounds such as aluminum trichloride. It will be
appreciated that the ALD coating applied to the support surface of
the vessel may be specifically adapted to a particular vaporizable
solid material. It will also be appreciated that the ALD coating
may be applied to all interior surface in the interior volume of
the vessel, including the wall and floor surface of the vessel as
well as the surface presented by any tray or other support
structure for the vaporizable solid that is disposed in the
interior volume of the vessel.
[0252] The ensuing disclosure is directed to various illustrative
examples of coated substrate articles, devices, and apparatus of
the present disclosure, exemplifying specific features, aspects,
and characteristics of the coating technology described herein.
[0253] Alumina coatings in accordance with the present disclosure
may be applied to surfaces of holders utilized in vaporizer
ampoules such as ampoules of the type shown in FIG. 3 hereof, as
previously described herein. FIG. 15 is a perspective view of a
stainless steel holder usefully employed in a vaporizer ampoule for
aluminum trichloride (AlCl.sub.3) solid precursor delivery for an
aluminum process, in which the aluminum trichloride precursor is
supported by the holder and volatilized to form aluminum
trichloride precursor vapor for discharge from the vaporizer
ampoule and transport through associated flow circuitry to the
aluminum process. The aluminum process may for example be employed
for metallization of a semiconductor device structure on and/or in
a suitable wafer substrate.
[0254] FIG. 16 is a perspective view of a stainless steel holder of
the type shown in FIG. 15, as coated by atomic layer deposition
with a coating of alumina thereon, so that the stainless steel
surface is encapsulated by the alumina coating in the corrosive
environment involving aluminum trichloride (AlCl.sub.3) exposure to
which the holder is subjected in use and operation of the vaporizer
ampoule. By such alumina coating, the holder is protected against
corrosion, and metals contamination of the precursor vapor is
substantially reduced. In addition to such alumina coating of the
holder, the entire interior surface of the vaporizer ampoule may
likewise be coated, as well as exterior surfaces of the ampoule, to
provide extended protection against the corrosive environment
deriving from the processing of the aluminum trichloride
(AlCl.sub.3) solid precursor to volatilize same for generation of
precursor vapor for the aluminum process, or for other usage.
[0255] The alumina coating on the surface of the holder and/or
other vaporizer ampoule services may be of any suitable thickness,
and may for example be in a thickness range of from 20 nm to 250 nm
or more. In various embodiments, the coating thickness on the
holder surfaces may be in a range of from 50 to 125 nm. It will be
appreciated that any suitable thickness of the alumina coating may
be applied by carrying out the corresponding vapor deposition
operation for a corresponding number of deposition cycles and
deposition times, with a suitable thickness being determinable by
empirical methods as appropriate to provide a desired level of
anti-corrosion protection to the metal surface.
[0256] FIG. 17 is a schematic elevation view of the alumina coating
applied by atomic layer deposition to the stainless steel
substrate, as described above in application to the solid precursor
holder utilized in the vaporizer ampoule. The alumina coating
provides corrosion resistance, prevents chemical reaction with the
substrate, and reduces metals contamination in use of the vaporizer
for aluminum trichloride precursor vapor generation.
[0257] In another application, yttria coatings may be applied to
surfaces of etching apparatus or apparatus components, e.g.,
surfaces of injector nozzles used in plasma etch equipment. FIG. 18
shows channels of a plasma etch apparatus coated with yttria
(Y.sub.2O.sub.3). Yttria provides an etch resistant coating that is
suitable for surfaces and parts of complicated shape, such as high
aspect ratio features. When deposited by atomic layer deposition,
yttria forms a dense, conformal, pin-hole free coating that is
resistant to etching, and provides substantially reduced particle
shedding and erosion in relation to surfaces lacking such yttria
coating.
[0258] Yttria coatings may be applied by atomic layer deposition
over alumina, as in the schematic elevation view of FIG. 19. In
application to plasma etching equipment and equipment components,
the ALD yttria layer provides enhanced corrosion-resistance and
etch-resistance, protecting the underlying surface against
deleterious plasma exposure, such as exposure to chloro- and
fluoro- and other halogen-based plasmas. The ALD yttria layer
thereby reduces generation of unwanted particles, and increases the
lifetime of parts of the plasma etching equipment whose surfaces
are coated with the yttria coating.
[0259] In another application, load lock components employed for
etch chamber apparatus are exposed in use to residual etch
chemistries from the etch chamber, resulting in severe corrosion of
metal components. An example is a diffuser plate, which may be
constructed of stainless steel or other metal or metal alloy, with
a filter membrane, formed for example of nickel or other metal or
metal alloy. Such diffuser plate assembly may be coated with an
alumina coating to encapsulate and protect the diffuser plate and
filter membrane. By complete encapsulation of the filter membrane,
corrosion of the membrane is prevented.
[0260] FIG. 20 is a photograph of a diffuser plate assembly,
including a stainless steel frame and a nickel filter membrane, as
coated with an alumina coating. FIG. 21 is a schematic elevation
view of the diffuser plate assembly, in which the stainless steel
frame and nickel membrane are encapsulated with ALD alumina. The
ALD coating provides a corrosion resistant and etch resistant layer
that protects against deleterious chemistries, e.g., hydrogen
bromide-based chemistries, reducing particles, and increasing the
lifetime of the assembly.
[0261] Another application relates to semiconductor process
equipment that is exposed to chlorine-based precursors from ALD
processing, and to fluorine-based plasmas from chamber cleaning
operations. In such applications, yttria coatings may be employed
to provide good etch resistance and to coat parts with complicated
shapes. One approach in such applications is the use of a
combination of physical vapor deposition (PVD) and atomic layer
deposition (ALD) of yttria, with ALD being employed for thinner
coating of high aspect ratio features and critical elements, and
thicker coating of PVD for the remainder of the part. In such
application, the yttria ALD layer provides corrosion-resistance and
etch-resistance, protection against fluorine-based chemistries and
fluorine-based plasmas, reducing particle generation and increasing
lifetime of parts that are coated with the protective yttria
coating.
[0262] A further application relates to coating of quartz envelopes
structures, such as bulbs of ultraviolet (UV) curing lamps that are
used in back end of line (BEOL) and front end of line (FEOL) UV
curing operations. In the operation of UV lamps, such as those in
which the bulb is fabricated of quartz, mercury will diffuse into
the quartz during operation at the high temperatures involved,
e.g., on the order of 1000.degree. C., and such mercury diffusion
will result in degradation of the UV lamp and substantial
shortening of its operational service life. To combat such mercury
migration into the quartz envelope (bulb) material, alumina and/or
yttria is coated on the interior surface of the bulb to provide a
diffusion barrier layer against incursion of mercury into the
quartz envelope material.
[0263] More generally, alumina coatings may be employed to overcoat
and encapsulate metal components of various types, to impart
corrosion resistance, prevent chemical reaction with the substrate,
and to reduce metals contamination, so that operating service life
of components, such as gas lines, valves, tubes, housings, and the
like, are correspondingly extended. By use of atomic layer
deposition, interior surfaces of parts can be coated, including
parts with complex interior surface geometry, and layers of alumina
or other protective coatings may be employed to provide dense,
pin-hole free and conformal protective layers over the substrate
surface.
[0264] Another application of protective coatings of the present
disclosure is the protective coating of plasma source surfaces,
such as are used in semiconductor manufacturing, and manufacture of
flat-panel displays, as well as solar panel manufacturing. Such
plasma sources may be of any suitable type, and may for example
generate ammonia plasmas, hydrogen plasmas, nitrogen trifluoride
plasmas, and plasmas of other varieties. The protective coatings
can be utilized in place of anodizing surfaces of plasma-wetted
parts, to provide enhanced plasma etch resistance, e.g., greater
than 1000 hours exposure to NF.sub.3 plasma, while accommodating
hydrogen (H*) and fluorine (F*) surface recombination, and high
electrical standoff voltages, e.g., greater than 1000 V.
[0265] An example plasma source apparatus may be formed of
aluminum, or an aluminum compound such as aluminum oxynitride, in
which a plasma channel and a water channel of the apparatus are
coated with coatings. The plasma channel coating and the water
channel coating may comprise an ALD coating of alumina, over which
is deposited a physical vapor deposition (PVD) coating of aluminum
oxynitride (AlON), as shown in the schematic elevation view of FIG.
22, showing the aluminum substrate, the ALD coating of alumina, and
the PVD coating of AlON. The thicknesses of the respective alumina
and aluminum oxynitride coatings may be of any suitable thickness.
By way of example, the thickness of the alumina coating may be in a
range of from 0.05 to 5 .mu.m, and the thickness of the PVD coating
may be in a range of from 2 to 25 .mu.m. In a specific embodiment,
the alumina coating has a thickness of 1 .mu.m, and the PVD AlON
coating has a thickness of 10 .mu.m. In the structure, the PVD AlON
coating provides the apparatus with etch resistance and plasma
surface recombination capability, and the alumina coating, in
addition to providing etch resistance provides an electrical
standoff coating.
[0266] A further application relates to dielectric stacks for hot
chuck components, which may have a layer structure as shown in FIG.
23. As shown, an alumina substrate has an electrode metal, e.g.,
nickel, thereon, on which is an electrical stand-off layer of ALD
alumina. Deposited on the alumina layer is a PVD coating of
aluminum oxynitride, and deposited on the AlON layer is a layer of
chemical vapor deposition (CVD) deposited silicon oxynitride
(SiON). In this layer structure, the CVD SiON layer provides a
clean way for contact surface and electrical spacer, the PVD AlON
layer provides a coefficient of thermal expansion (CTE) buffer
layer, the ALD layer of alumina provides an electrical stand-off
layer, and the nickel provides an electrode metal layer, on the
alumina substrate.
[0267] A still further application relates to plasma activation
chuck components of plasma activation chambers, in which aluminum
parts are coated with a multilayer stack including the multilayer
stacks shown in FIGS. 24 and 25. The multilayer stack of FIG. 24
includes a chemical vapor deposition-applied layer of silicon on
the aluminum substrate, with an ALD layer of zirconia on the CVD Si
layer. In this multilayer stack, the ALD layer of zirconia
functions to provide a clean, dense way for contact surface,
serving as a diffusion barrier layer, and an electrical standoff.
The CVD silicon layer provides a clean buffer layer on the aluminum
substrate. The multilayer stack of FIG. 25 includes a CVD layer of
silicon oxynitride on the aluminum substrate, and an ALD layer of
alumina on the CVD SiON coating layer, wherein the ALD alumina
layer functions as an electrical stand-off layer, a diffusion
barrier layer, and a layer providing a clean, dense way for contact
surface. The CVD SiON layer provides a clean buffer layer in the
multilayer coating structure.
[0268] A further application of the coating technology of the
present disclosure relates to coating of porous matrix and filter
articles, in which coatings such as alumina may be deposited by
atomic layer deposition, which enables independent control of
penetration depth and coating thickness in the porous matrix or
filter material. Either partial alumina coating penetration or full
alumina coating penetration may be employed, depending on the
article and its specific end use.
[0269] FIG. 26 is a micrograph of porous material having a 1.5 mm
wall thickness and pore size of 2-4 .mu.m, coated with alumina by
atomic layer deposition. FIG. 27 is a schematic representation of
an encapsulated membrane, comprising a membrane formed of stainless
steel, nickel, titanium, or other suitable material, which has been
fully encapsulated with alumina deposited by ALD, to provide the
encapsulated membrane with corrosion resistance and etch
resistance, protection against chemical attack, reduction of
particle generation, and reduction of metals contamination.
[0270] The use of atomic layer deposition, as indicated, provides
an ability to independently control coating penetration depth and
coating thickness. This ability is usefully employed to control
pore size and flow restriction of ultra-fine membranes, such as for
example those with nominal pore size in a range of from 20 nm to
250 nm, e.g., a nominal pore size on the order of 100 nm.
[0271] FIG. 28 is a photomicrograph of a coated filter, wherein the
coating is alumina, having a coating penetration depth of 35 .mu.m.
FIG. 29 is a photomicrograph of a coated filter, wherein the
coating is alumina, having a coating penetration depth of 175
.mu.m.
[0272] Consistent with the preceding disclosure herein, the present
disclosure relates in one aspect to a solid vaporizer apparatus
comprising a container defining therein an interior volume, an
outlet configured to discharge precursor vapor from the container,
and support structure in the interior volume of the container
adapted to support solid precursor material thereon for
volatilization thereof to form the precursor vapor, wherein the
solid precursor material comprises aluminum precursor, and wherein
at least part of surface area in the interior volume is coated with
an alumina coating. In various embodiments of such solid vapor
apparatus, the surface area may comprise at least one of surface
area of the support structure, and surface area of the container in
said interior volume. In other embodiments, the surface area may
comprise surface area of the support structure, and surface area of
the container in said interior volume. In still other embodiments,
the surface area in the interior volume that is coated with an
alumina coating, comprises stainless steel. In various
implementations of the solid vaporizer apparatus, the alumina
coating may have thickness in a range of from 20 to 125 nm. the
alumina coating may for example comprise an ALD alumina coating in
any of the foregoing aspects and embodiments.
[0273] The disclosure in another aspect relates to a method of
enhancing corrosion resistance of a stainless steel structure,
material, or apparatus that in use or operation is exposed to
aluminum halide, said method comprising coating said stainless
steel structure, material, or apparatus with an alumina coating.
The alumina coating in such method may for example have thickness
in a range of from 20 to 125 nm. The alumina coating may for
example be applied by atomic layer deposition.
[0274] In a further aspect, the disclosure relates to a
semiconductor processing etching structure, component, or apparatus
that in use or operation is exposed to etching media, said
structure, component, or apparatus being coated with a coating
comprising a layer of yttria, wherein the layer of yttria
optionally overlies a layer of alumina in said coating. The etching
structure, component, or apparatus may for example comprise an
etching apparatus injector nozzle.
[0275] Another aspect of the disclosure relates to a method of
enhancing corrosion resistance and etch resistance of a
semiconductor processing etching structure, component, or apparatus
that in use or operation is exposed to etching media, said method
comprising coating the structure, component, or apparatus with a
coating comprising a layer of yttria, wherein the layer of yttria
optionally overlies a layer of alumina in said coating.
[0276] Still another aspect of the disclosure relates to an etch
chamber diffuser plate comprising a nickel membrane encapsulated
with an alumina coating. In such etch chamber diffuser plate, the
alumina coating may comprise an ALD alumina coating.
[0277] A further aspect of the disclosure relates to a method of
enhancing corrosion resistance and etch resistance of an etch
chamber diffuser plate comprising a nickel membrane, comprising
coating the nickel membrane with an encapsulating coating of
alumina. The coating of alumina may for example comprise an ALD
coating.
[0278] The disclosure in another aspect relates to a vapor
deposition processing structure, component, or apparatus that in
use or operation is exposed to halide media, said structure,
component, or apparatus being coated with a coating of yttria
comprising an ALD base coating of yttria, and a PVD overcoating of
yttria. In such structure, component, or apparatus, the surface
that is coated with the ALD base coating of yttria, and the PVD
overcoating of yttria, may comprise aluminum.
[0279] A further aspect of the disclosure relates to a method of
enhancing corrosion resistance and etch resistance of a vapor
deposition processing structure, component, or apparatus that in
use or operation is exposed to halide media, said method comprising
coating the structure, component, or apparatus with a coating of
yttria comprising an ALD base coating of yttria, and a PVD over
coating of yttria. As noted above, the structure, component, or
apparatus may comprise aluminum surface that is coated with the
coating of yttria.
[0280] Another aspect the disclosure relates to a quartz envelope
structure coated on an interior surface thereof with an alumina
diffusion barrier layer.
[0281] A corresponding aspect of the disclosure relates to a method
of reducing diffusion of mercury into a quartz envelope structure
susceptible to such diffusion in operation thereof, said method
comprising coating an interior surface of the quartz envelope
structure with an alumina diffusion barrier layer.
[0282] The disclosure in a further aspect relates to a plasma
source structure, component, or apparatus that in use or operation
is exposed to plasma and voltage exceeding 1000 V, wherein
plasma-wetted surface of said structure, component or apparatus is
coated with an ALD coating of alumina, and said alumina coating is
overcoated with a PVD coating of aluminum oxynitride. The
plasma-wetted surface may for example comprise aluminum or aluminum
oxynitride.
[0283] A further aspect of the disclosure relates to a method of
enhancing service life of a plasma source structure, component, or
apparatus that in use or operation is exposed to plasma and voltage
exceeding 1000 V, said method comprising coating plasma-wetted
surface of said structure, component or apparatus with an ALD
coating of alumina, and over coating said alumina coating with a
PVD coating of aluminum oxynitride. As indicated above, the
plasma-wetted surface may comprise aluminum or aluminum
oxynitride.
[0284] An additional aspect of the disclosure relates to a
dielectric stack, comprising sequential layers including a base
layer of alumina, a nickel electrode layer thereon, an ALD alumina
electrical stand-off layer on the nickel electrode layer, a PVD
aluminum oxynitride thermal expansion buffer layer on the ALD
alumina electrical stand-off layer, and a CVD silicon oxynitride
wafer contact surface and electrical spacer layer on the PVD
aluminum oxynitride thermal expansion buffer layer.
[0285] A plasma activation structure, component, or apparatus is
contemplated in another aspect of the disclosure, comprising
aluminum surface coated with one of the multilayer coatings of (i)
and (ii): (i) a base coat of CVD silicon on the aluminum surface,
and a layer of ALD zirconia on the base coat of CVD silicon; and
(ii) a base coat of CVD silicon oxynitride on the aluminum surface,
and a layer of ALD alumina on the base coat of CVD silicon
oxynitride.
[0286] A corresponding method is contemplated for reducing particle
formation and metal contamination for an aluminum surface of a
plasma activation structure, component, or apparatus, said method
comprising coating the aluminum surface with one of the multilayer
coatings of (i) and (ii): (i) a base coat of CVD silicon on the
aluminum surface, and a layer of ALD zirconia on the base coat of
CVD silicon; and (ii) a base coat of CVD silicon oxynitride on the
aluminum surface, and a layer of ALD alumina on the base coat of
CVD silicon oxynitride.
[0287] The disclosure contemplates, in another aspect, a porous
matrix filter comprising a membrane formed of stainless steel,
nickel, or titanium, wherein the membrane is encapsulated with
alumina to a coating penetration depth in a range of from 20 to
2000 .mu.m. More specifically, in various embodiments, the porosity
may have nominal pore size in a range of from 10 to 1000 nm.
[0288] Another aspect of the disclosure relates to a method of
making a porous matrix filter comprising encapsulating a membrane
formed of stainless steel, nickel, or titanium with alumina to a
coating penetration depth in a range of from 20 to 2000 .mu.m. in a
specific embodiment of such method, the encapsulating comprises ALD
of the alumina, and the method is conducted to provide porosity in
the porous matrix filter having nominal pore size in a range of
from 10 to 1000 nm.
[0289] While the disclosure has been set forth herein in reference
to specific aspects, features and illustrative embodiments, it will
be appreciated that the utility of the disclosure is not thus
limited, but rather extends to and encompasses numerous other
variations, modifications and alternative embodiments, as will
suggest themselves to those of ordinary skill in the field of the
present disclosure, based on the description herein.
Correspondingly, the disclosure as hereinafter claimed is intended
to be broadly construed and interpreted, as including all such
variations, modifications and alternative embodiments, within its
spirit and scope.
* * * * *