U.S. patent application number 11/555087 was filed with the patent office on 2007-08-16 for methods and apparatus for preventing deposition of reaction products in process abatement reactors.
Invention is credited to Daniel O. Clark, Shaun W. Crawford, Sebastien Raoux, Robert M. Vermeulen.
Application Number | 20070190469 11/555087 |
Document ID | / |
Family ID | 38006466 |
Filed Date | 2007-08-16 |
United States Patent
Application |
20070190469 |
Kind Code |
A1 |
Clark; Daniel O. ; et
al. |
August 16, 2007 |
METHODS AND APPARATUS FOR PREVENTING DEPOSITION OF REACTION
PRODUCTS IN PROCESS ABATEMENT REACTORS
Abstract
In certain embodiments, methods, systems, and apparatus are
provided for use in removing pollutants from a gas stream. The
invention includes a thermal reaction unit formed from a plurality
of stacked porous ceramic rings. The porous rings include
perforations adapted to allow fluid to be flowed into the thermal
reaction unit. By flowing fluid through the porous rings,
deposition of waste effluent and/or by-products on the interior of
the thermal reaction unit is prevented. Numerous other aspects are
provided.
Inventors: |
Clark; Daniel O.;
(Pleasanton, CA) ; Raoux; Sebastien; (Santa Clara,
CA) ; Vermeulen; Robert M.; (Pleasant Hill, CA)
; Crawford; Shaun W.; (San Ramon, CA) |
Correspondence
Address: |
DUGAN & DUGAN, PC
55 SOUTH BROADWAY
TARRYTOWN
NY
10591
US
|
Family ID: |
38006466 |
Appl. No.: |
11/555087 |
Filed: |
October 31, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60731719 |
Oct 31, 2005 |
|
|
|
Current U.S.
Class: |
431/5 |
Current CPC
Class: |
B01D 53/38 20130101;
B01D 53/79 20130101; F23C 7/02 20130101; F23G 7/065 20130101; C23C
16/4412 20130101; B01D 2258/0216 20130101; B01D 53/8659 20130101;
F23D 2900/00016 20130101; B01D 53/8662 20130101; B01D 53/68
20130101; B01D 53/74 20130101; B01D 2251/2062 20130101; F23M 5/00
20130101; B01D 2251/106 20130101; B01D 2251/104 20130101 |
Class at
Publication: |
431/005 |
International
Class: |
F23G 7/08 20060101
F23G007/08; F23J 15/00 20060101 F23J015/00; F23D 14/00 20060101
F23D014/00 |
Claims
1. An apparatus for use during the abatement of a semiconductor
manufacturing process comprising: a thermal reaction unit having:
an exterior wall having a plurality of perforations adapted to pass
of a fluid therethrough; an interior porous wall that defines a
central chamber, the interior porous wall formed from a plurality
of stacked porous sections; at least one waste gas inlet in fluid
communication with the central chamber and adapted to introduce a
gaseous waste stream to the central chamber; a thermal mechanism
positioned within the central chamber and adapted to decompose the
gaseous waste stream within the central chamber, thereby forming
reaction products; and a fluid delivery system adapted to provide a
fluid through the perforations of the exterior wall and to the
central chamber through the interior porous wall at a sufficient
force to reduce deposition of reaction products on an inner surface
of the interior porous wall of the central chamber; wherein the
perforations in the exterior wall provide a pressure drop across
the thermal reaction unit of about 0.1 to about 5 psi.
2. An apparatus for use during the abatement of a semiconductor
manufacturing process comprising: a thermal reaction unit having:
an exterior wall having a plurality of perforations adapted to pass
of a fluid therethrough; an interior porous wall that defines a
central chamber, the interior porous wall formed from a plurality
of stacked porous sections; at least one waste gas inlet in fluid
communication with the central chamber and adapted to introduce a
gaseous waste stream to the central chamber; a thermal mechanism
positioned within the central chamber and adapted to decompose the
gaseous waste stream within the central chamber, thereby forming
reaction products; and a fluid delivery system adapted to provide a
fluid through the perforations of the exterior wall and to the
central chamber through the interior porous wall at a sufficient
force to reduce deposition of reaction products on an inner surface
of the interior porous wall of the central chamber; wherein the
fluid deliver system is adapted to provide at least one of water,
steam, air, clean dry air, clean enriched air, oxygen enriched air,
oxygen depleted air, inert gas, a reagent, an oxidizer and depleted
air; wherein the fluid delivery system is adapted to provide a
fluid at a pressure of about 600 psig or less.
3. The apparatus of claim 2 wherein the fluid delivery system is
adapted to provide at least one of ozone, hydrogen peroxide and
ammonia.
4. The apparatus of claim 2 wherein the fluid delivery system is
adapted to provide only water or only air.
5. The apparatus of claim 2 wherein the fluid delivery system is
adapted to provide a fluid under periodic pulsing.
6. The apparatus of claim 5 wherein the fluid delivery system is
adapted to provide fluid using a pulse duration of from about 3 ms
to 1 second.
7. The apparatus of claim 2 wherein the fluid delivery system is
adapted to provide a fluid at a pressure of less than to about 100
psig.
8. The apparatus of claim 2 wherein the fluid delivery system is
adapted to provide a fluid at a pressure of about 50 psig to about
100 psig.
9. The apparatus of claim 2 wherein the fluid delivery system is
adapted to provide a fluid at a pressure of about 5 psig to about
50 psig.
10. The apparatus of claim 2 wherein the fluid delivery system is
adapted to provide a fluid at a pressure of about 1/10 psig to
about 5 psig.
11. The apparatus of claim 2 wherein the thermal reaction unit
includes at least one oxidant inlet positioned to introduce an
oxidant to the central chamber.
12. The apparatus of claim 2 wherein the thermal reaction unit
includes at least one additional gas inlet for introducing a
combustible fuel to the central chamber.
13. The apparatus of claim 12 wherein the combustible fuel
comprises at least one of oxygen, city gas, LPG, propane, methane,
hydrogen, butane, ethanol, 13A and natural gas.
14. A method for use during the abatement of a semiconductor
manufacturing process comprising: providing a thermal reaction unit
having: an exterior wall having a plurality of perforations adapted
to pass of a fluid therethrough; an interior porous wall that
defines a central chamber, the interior porous wall formed from a
plurality of stacked porous sections; at least one waste gas inlet
in fluid communication with the central chamber and adapted to
introduce a gaseous waste stream to the central chamber; a thermal
mechanism positioned within the central chamber and adapted to
decompose the gaseous waste stream within the central chamber,
thereby forming reaction products; and a fluid delivery system
adapted to provide a fluid through the perforations of the exterior
wall and to the central chamber through the interior porous wall at
a sufficient force to reduce deposition of reaction products on an
inner surface of the interior porous wall of the central chamber;
wherein the perforations in the exterior wall provide a pressure
drop across the thermal reaction unit of about 0.1 to about 5 psi;
and employing the thermal reaction unit to abate the semiconductor
device manufacturing process.
15. A method for use during the abatement of a semiconductor
manufacturing process comprising: providing a thermal reaction unit
having: an exterior wall having a plurality of perforations adapted
to pass a fluid therethrough; an interior porous wall that defines
a central chamber, the interior porous wall formed from a plurality
of stacked porous sections; at least one waste gas inlet in fluid
communication with the central chamber and adapted to introduce a
gaseous waste stream to the central chamber; a thermal mechanism
positioned within the central chamber and adapted to decompose the
gaseous waste stream within the central chamber, thereby forming
reaction products; and a fluid delivery system adapted to provide a
fluid through the perforations of the exterior wall and to the
central chamber through the interior porous wall at a sufficient
force to reduce deposition of reaction products on an inner surface
of the interior porous wall of the central chamber; wherein the
fluid deliver system is adapted to provide at least one of water,
steam, air, clean dry air, clean enriched air, oxygen enriched air,
oxygen depleted air, inert gas, a reagent, an oxidizer and depleted
air; wherein the fluid delivery system is adapted to provide a
fluid at a pressure of about 600 psig or less; and employing the
thermal reaction unit to abate the semiconductor device
manufacturing process.
16. The method of claim 15 further comprising employing the fluid
delivery system to provide at least one of ozone, hydrogen peroxide
and ammonia during abatement.
17. The method of claim 15 further comprising employing the fluid
delivery system to provide only water or only air during
abatement.
18. The method of claim 15 further comprising employing the fluid
delivery system to provide a fluid under periodic pulsing during
abatement.
19. The method of claim 18 further comprising employing the fluid
delivery system to provide fluid using a pulse duration of from
about 3 ms to 1 second.
20. The method of claim 15 further comprising employing the fluid
delivery system to provide a fluid at a pressure of less than to
about 100 psig.
21. The method of claim 15 further comprising employing the fluid
delivery system to provide a fluid at a pressure of about 50 psig
to about 100 psig.
22. The method of claim 15 further comprising employing the fluid
delivery system to provide a fluid at a pressure of about 5 psig to
about 50 psig.
23. The method of claim 15 further comprising employing the fluid
delivery system to provide a fluid at a pressure of about 1/10 psig
to about 5 psig.
24. The method of claim 15 wherein the thermal reaction unit
includes at least one oxidant inlet positioned to introduce an
oxidant to the central chamber.
25. The method of claim 15 wherein the thermal reaction unit
includes at least one additional gas inlet for introducing a
combustible fuel to the central chamber.
26. The method of claim 15 further comprising introducing at least
one of oxygen, city gas, LPG, propane, methane, hydrogen, butane,
ethanol, 13A and natural gas to the central chamber during
abatement.
Description
[0001] The present application claims priority from U.S.
Provisional Patent Application Ser. No. 60/731,719, filed Oct. 31,
2005, which is hereby incorporated by reference herein in its
entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to improved systems and
methods for the abatement of industrial effluent fluids, such as
effluent gases produced in semiconductor manufacturing processes,
while reducing the deposition of reaction products in the abatement
systems.
BACKGROUND
[0003] The gaseous effluents from the manufacturing of
semiconductor materials, devices, products and memory articles
involve a wide variety of chemical compounds used and produced in
the process facility. These compounds include inorganic and organic
compounds, breakdown products of photo-resist and other reagents,
and a wide variety of other gases that must be removed from the
waste gas before being vented from the process facility into the
atmosphere.
[0004] Semiconductor manufacturing processes utilize a variety of
chemicals, many of which have extremely low human tolerance levels.
Such materials include gaseous hydrides of antimony, arsenic,
boron, germanium, nitrogen, phosphorous, silicon, selenium, silane,
silane mixtures with phosphine, argon, hydrogen, organosilanes,
halosilanes, halogens, organometallics and other organic
compounds.
[0005] Halogens, e.g., fluorine (F.sub.2) and other fluorinated
compounds, are particularly problematic among the various
components requiring abatement. The electronics industry uses
perfluorinated compounds (PFCs) in wafer processing tools to remove
residue from deposition steps and to etch thin films. PFCs are
recognized to be strong contributors to global warming and the
electronics industry is working to reduce the emissions of these
gases. The most commonly used PFCs include, but are not limited to,
CF.sub.4, C.sub.2F.sub.6, SF.sub.6, C.sub.3F.sub.8, C.sub.4H.sub.8,
C.sub.4H.sub.8O and NF.sub.3. In practice, these PFCs are
dissociated in a plasma to generate highly reactive fluoride ions
and fluorine radicals, which do the actual cleaning and/or etching.
The effluent from these processing operations include mostly
fluorine, silicon tetrafluoride (SiF.sub.4), hydrogen fluoride
(HF), carbonyl fluoride (COF.sub.2), CF.sub.4 and
C.sub.2F.sub.6.
[0006] Improved methods and apparatus for abating such effluent
streams are desired.
SUMMARY OF THE INVENTION
[0007] In certain embodiments, a thermal reactor is provided for
use during the abatement of a semiconductor manufacturing process.
The thermal reactor includes a thermal reaction unit having (a) an
interior porous wall that defines a central chamber, the interior
porous wall formed from a plurality of stacked porous sections; (b)
at least one waste gas inlet in fluid communication with the
central chamber and adapted to introduce a gaseous waste stream to
the central chamber; (c) a thermal mechanism positioned within the
central chamber and adapted to decompose the gaseous waste stream
within the central chamber, thereby forming reaction products; and
(d) a fluid delivery system adapted to provide a fluid to the
central chamber through the interior porous wall at a sufficient
force to reduce deposition of reaction products on an inner surface
of the interior porous wall of the central chamber. At least one of
the porous sections has one or more of (i) a property that varies
within the porous section; and (ii) a property that differs from a
property of at least one other porous section of the interior
porous wall.
[0008] In certain embodiments, a replacement part is provided for
use in an abatement system. The replacement part includes a
stackable and replaceable porous chamber section having a plurality
of features that allow the porous chamber section to be stacked
with other porous chamber sections so as to form a porous wall that
defines a central chamber for use during decomposition of gaseous
waste from a semiconductor manufacturing process. The porous
chamber section has sufficient porosity to allow transfer of fluid
from outside the porous chamber section through the porous chamber
section and into the central chamber during a decomposition process
performed within the central chamber so as to reduce movement of
reaction products toward an interior surface of the porous chamber
section. The porous chamber section has a shape selected from the
group consisting of round, elliptical, triangular, square,
rectangular, polygonal, pentagonal, hexagonal and octagonal.
Further, the porous chamber section has one or more of (a) a
property that varies within the porous chamber section; and (b) a
property that differs from a property of at least one other porous
chamber section of the porous wall.
[0009] In certain embodiments, an apparatus is provided for use in
removing pollutants from a gas stream. The apparatus includes a
thermal reaction unit formed from a plurality of stacked porous
ceramic rings. A first of the porous ceramic rings has a first
coefficient of thermal expansion (CTE) and a second of the porous
ceramic rings has a second CTE.
[0010] In certain embodiments, an apparatus is provided for use in
removing pollutants from a gas stream. The apparatus includes a
thermal reaction unit formed from a plurality of stacked porous
ceramic rings. A first of the porous ceramic rings has a first
purity level and a second of the porous ceramic rings has a second
purity level.
[0011] In certain embodiments, an apparatus is provided for use in
removing pollutants from a gas stream. The apparatus includes a
thermal reaction unit formed from a plurality of stacked porous
ceramic rings. A first of the porous ceramic rings has a first
dopant level and a second of the porous ceramic rings has a second
dopant level.
[0012] In certain embodiments, an apparatus is provided for use
during the abatement of a semiconductor manufacturing process. The
apparatus includes a thermal reaction unit having (a) an exterior
wall having a plurality of perforations adapted to pass of a fluid
therethrough; (b) an interior porous wall that defines a central
chamber, the interior porous wall formed from a plurality of
stacked porous sections; (c) at least one waste gas inlet in fluid
communication with the central chamber and adapted to introduce a
gaseous waste stream to the central chamber; (d) a thermal
mechanism positioned within the central chamber and adapted to
decompose the gaseous waste stream within the central chamber,
thereby forming reaction products; and (e) a fluid delivery system
adapted to provide a fluid through the perforations of the exterior
wall and to the central chamber through the interior porous wall at
a sufficient force to reduce deposition of reaction products on an
inner surface of the interior porous wall of the central chamber.
The perforations in the exterior wall provide a pressure drop
across the thermal reaction unit of about 0.1 to about 5 psi.
[0013] In certain embodiments, an apparatus is provided for use
during the abatement of a semiconductor manufacturing process. The
apparatus includes a thermal reaction unit having (a) an exterior
wall having a plurality of perforations adapted to pass of a fluid
therethrough; (b) an interior porous wall that defines a central
chamber, the interior porous wall formed from a plurality of
stacked porous sections; (c) at least one waste gas inlet in fluid
communication with the central chamber and adapted to introduce a
gaseous waste stream to the central chamber; (d) a thermal
mechanism positioned within the central chamber and adapted to
decompose the gaseous waste stream within the central chamber,
thereby forming reaction products; and (e) a fluid delivery system
adapted to provide a fluid through the perforations of the exterior
wall and to the central chamber through the interior porous wall at
a sufficient force to reduce deposition of reaction products on an
inner surface of the interior porous wall of the central chamber.
The fluid deliver system is adapted to provide at least one of
water, steam, air, clean dry air, clean enriched air, oxygen
enriched air, oxygen depleted air, inert gas, a reagent, an
oxidizer and depleted air. The fluid delivery system also is
adapted to provide a fluid at a pressure of about 600 psig or
less.
[0014] In certain embodiments, a method is provided for use during
the abatement of a semiconductor manufacturing process. The method
includes providing a thermal reaction unit having (a) an exterior
wall having a plurality of perforations adapted to pass of a fluid
therethrough; (b) an interior porous wall that defines a central
chamber, the interior porous wall formed from a plurality of
stacked porous sections; (c) at least one waste gas inlet in fluid
communication with the central chamber and adapted to introduce a
gaseous waste stream to the central chamber; (d) a thermal
mechanism positioned within the central chamber and adapted to
decompose the gaseous waste stream within the central chamber,
thereby forming reaction products; and (e) a fluid delivery system
adapted to provide a fluid through the perforations of the exterior
wall and to the central chamber through the interior porous wall at
a sufficient force to reduce deposition of reaction products on an
inner surface of the interior porous wall of the central chamber.
The perforations in the exterior wall provide a pressure drop
across the thermal reaction unit of about 0.1 to about 5 psi. The
method also includes employing the thermal reaction unit to abate
the semiconductor device manufacturing process.
[0015] In certain embodiments, a method is provided for use during
the abatement of a semiconductor manufacturing process. The method
includes providing a thermal reaction unit having (a) an exterior
wall having a plurality of perforations adapted to pass of a fluid
therethrough; (b) an interior porous wall that defines a central
chamber, the interior porous wall formed from a plurality of
stacked porous sections; (c) at least one waste gas inlet in fluid
communication with the central chamber and adapted to introduce a
gaseous waste stream to the central chamber; (d) a thermal
mechanism positioned within the central chamber and adapted to
decompose the gaseous waste stream within the central chamber,
thereby forming reaction products; and (e) a fluid delivery system
adapted to provide a fluid through the perforations of the exterior
wall and to the central chamber through the interior porous wall at
a sufficient force to reduce deposition of reaction products on an
inner surface of the interior porous wall of the central chamber.
The fluid deliver system is adapted to provide at least one of
water, steam, air, clean dry air, clean enriched air, oxygen
enriched air, oxygen depleted air, inert gas, a reagent, an
oxidizer and depleted air. The fluid delivery system also is
adapted to provide a fluid at a pressure of about 600 psig or less.
The method also includes employing the thermal reaction unit to
abate the semiconductor device manufacturing process.
[0016] In certain embodiments, a system is provided for
manufacturing electronic devices. The system includes (a) a
plurality of processing tools; (b) an abatement system for abating
pollutants from the processing tools and having a plurality of
inlet ports; and (c) a manifold for coupling pollutant outlet ports
of the plurality of processing tools to the plurality of inlet
ports of the abatement system.
[0017] In certain embodiments, a system is provided for
manufacturing electronic devices. The system includes (a) a
processing tool; (b) an abatement system for abating pollutants
from the processing tool and including a plurality of chambers,
each chamber including a plurality of inlet ports; and (c) a
manifold for coupling a pollutant outlet port of the processing
tool to the plurality of inlet ports of the abatement system.
[0018] In certain embodiments, a system is provided for
manufacturing electronic devices. The system includes (a) a
plurality of processing tools; and (b) an abatement system for
abating pollutants from the processing tools. The abatement system
includes a plurality of chambers, each including a plurality of
inlet ports. The system also includes a manifold for selectively
coupling pollutant outlet ports of the plurality of processing
tools to the plurality of inlet ports of the chambers of the
abatement system.
[0019] In certain embodiments, an apparatus is provided for use
during the abatement of a semiconductor manufacturing process. The
apparatus includes (a) a plurality of chambers, each chamber
including a plurality of waste stream inlet ports; and (b) a
manifold for selectively coupling pollutant outlet ports of a
plurality of processing tools to the plurality of waste stream
inlet ports of the chambers.
[0020] In certain embodiments, an apparatus is provided for use
during the abatement of a semiconductor manufacturing process. The
apparatus includes a thermal reaction unit having (a) an interior
porous wall that defines a central chamber and formed from a
plurality of stacked ceramic sections; (b) at least one waste gas
inlet in fluid communication with the central chamber and adapted
to introduce a gaseous waste stream to the central chamber; (c) a
thermal mechanism positioned within the central chamber and adapted
to decompose the gaseous waste stream within the central chamber,
thereby forming reaction products; and (d) a fluid delivery system
adapted to provide a fluid to the central chamber through the
interior porous wall with sufficient pressure to reduce deposition
of reaction products on an inner surface of the interior porous
wall of the central chamber. At least one of the stacked ceramic
sections is adapted to allow sensing of a characteristic of
contents of the central chamber
[0021] In certain embodiments, an apparatus is provided for use
during the abatement of a semiconductor manufacturing process. The
apparatus includes a thermal reaction unit having (a) an interior
porous wall that defines a central chamber, the interior porous
wall formed from a plurality of stacked ceramic sections; (b) at
least one waste gas inlet in fluid communication with the central
chamber, adapted to introduce a gaseous waste stream to the central
chamber, and disposed so as to direct the gaseous waste stream away
from the interior porous wall of the chamber; (d) a thermal
mechanism positioned within the central chamber and adapted to
decompose the gaseous waste stream within the central chamber,
thereby forming reaction products; and (e) a fluid delivery system
adapted to provide a fluid to the central chamber through the
interior porous wall with sufficient pressure to reduce deposition
of reaction products on an inner surface of the interior porous
wall of the central chamber.
[0022] Other features and aspects of the present invention will
become more fully apparent from the following detailed description,
the appended claims and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a cut away view of a thermal reaction unit, inlet
adaptor and lower quenching chamber that may be employed with the
present invention.
[0024] FIG. 2 is an elevational view of the interior plate of the
inlet adaptor of FIG. 1.
[0025] FIG. 3 is a partial cut-away view of the inlet adaptor of
FIG. 1.
[0026] FIG. 4 is a view of a center jet of FIG. 1.
[0027] FIG. 5 is a cut away view of the inlet adaptor and the
thermal reaction unit of FIG. 1.
[0028] FIG. 6A is an elevational view of a ceramic ring of the
thermal reaction unit of FIG. 1.
[0029] FIG. 6B is a partial cut-away view of the ceramic ring of
FIG. 6A.
[0030] FIG. 6C is a partial cut-away view of ceramic rings stacked
upon one another to define the thermal reaction chamber of FIG.
1.
[0031] FIG. 7 is a view of the sections of a perforated metal shell
that may be used in the chamber of FIG. 1.
[0032] FIG. 8 is an exterior view of an embodiment of the thermal
reaction unit of FIG. 1.
[0033] FIG. 9 is a partial cut-away view of an exemplary inlet
adaptor/thermal reaction unit joint for the reaction unit of FIG.
1.
[0034] FIG. 10 is a partial cut-away view of an exemplary shield
that may be positioned between the thermal reaction unit and the
lower quenching chamber of FIG. 1.
[0035] FIG. 11A is a partial cut-away view of the thermal reaction
unit in which the thermal reaction chamber is formed from a
plurality of stacked, porous ceramic sections.
[0036] FIG. 11B illustrates an embodiment of the thermal reaction
chamber of FIG. 11A in which each ceramic section is formed from
two ceramic subsections.
[0037] FIG. 12 is a schematic diagram of an exemplary thermal
reaction chamber defined by a plurality of ceramic sections.
[0038] FIG. 13 is a top view of an exemplary embodiment of the
thermal reaction unit in which inlet ports to the reaction chamber
are angled.
DETAILED DESCRIPTION
[0039] The present invention relates to methods and systems for
providing controlled decomposition of effluent gases in a thermal
reactor while reducing accumulation of deposition products within
the system. The present invention further relates to an improved
thermal reactor design to reduce thermal reaction unit cracking
during the high temperature decomposition of effluent gases.
[0040] Waste gas to be abated may include, for example, species
generated by a semiconductor process and/or species that were
delivered to and egressed from the semiconductor process without
chemical alteration. As used herein, the term "semiconductor
process" is intended to be broadly construed to include any and all
processing and unit operations in the manufacture of semiconductor
products, flat panel displays and/or LCD products, as well as all
operations involving treatment or processing of materials used in
or produced by a semiconductor, flat panel display and/or LCD
manufacturing facility, as well as all operations carried out in
connection with the semiconductor, flat panel display and/or LCD
manufacturing facility not involving active manufacturing (examples
include conditioning of process equipment, purging of chemical
delivery lines in preparation of operation, etch cleaning of
process tool chambers, abatement of toxic or hazardous gases from
effluents produced by the semiconductor, flat panel display and/or
LCD manufacturing facility, etc.).
[0041] U.S. patent application Ser. No. 10/987,921, filed Nov. 12,
2004 (Attorney Docket No. 723), which is hereby incorporated by
reference herein in its entirety and referred to as "the '921
Application") describes an improved thermal reaction system having
a thermal reaction unit 30 and a lower quenching chamber 150 as
shown in FIG. 1. The thermal reaction unit 30 includes a thermal
reaction chamber 32, and an inlet adaptor 10 including a top plate
18, at least one waste gas inlet 14, at least one fuel inlet 17,
optionally at least one oxidant inlet 11, burner jets 15, a center
jet 16 and an interior plate 12 which is positioned at or within
the thermal reaction chamber 32 (see also FIG. 3 for a schematic of
the inlet adaptor independent of the thermal reaction unit). The
inlet adaptor includes the fuel and oxidant gas inlets to provide a
fuel rich gas mixture to the system for the destruction of
contaminants. When oxidant is used, the fuel and oxidant may be
pre-mixed prior to introduction into the thermal reaction chamber.
Fuels contemplated include, but are not limited to, hydrogen,
methane, natural gas, propane, LPG and city gas, preferably natural
gas. Oxidants contemplated include, but are limited to, oxygen,
ozone, air, clean dry air (CDA) and oxygen- enriched air. Waste
gases to be abated comprise a species selected from the group
consisting of CF.sub.4, C.sub.2F.sub.6, SF.sub.6, C.sub.3F.sub.8,
C.sub.4H.sub.8, C.sub.4H.sub.8O, SiF.sub.4, BF.sub.3, NF.sub.3,
BH.sub.3, B.sub.2H.sub.6, B.sub.5H.sub.9, NH.sub.3, PH.sub.3,
SiH.sub.4, SeH.sub.2, F.sub.2, Cl.sub.2, HCl, HF, HBr, WF.sub.6,
H.sub.2, Al(CH.sub.3).sub.3, primary and secondary amines,
organosilanes, organometallics, and halosilanes.
[0042] Prior art inlet adaptors have included limited porosity
ceramic plates as the interior plate of the inlet adaptor. A
disadvantage of these limited porosity interior plates includes the
accumulation of particles on said surface, eventually leading to
inlet port clogging and flame detection error. The invention of the
'921 Application overcomes these disadvantages by using, in some
embodiments, a reticulated ceramic foam as the interior plate 12.
FIG. 2 represents an elevational view of the interior plate 12,
including the inlet ports 14, burner jets 15, a center jet port 16
and the reticulated ceramic foam 20 of the interior plate. The
reticulated ceramic foam 20 has a plurality of pores disposed
therethrough. As such, the passage of fluids through the pores of
the interior plate to the thermal reaction chamber 32 may reduce
the deposition of particulate matter at the surface of the interior
plate 12 and the walls of the thermal reaction unit 30 proximate to
the interior plate 12. The fluid may include any gas that is
preferably pressurized to a suitable pressure, which upon diffusion
through the material is sufficient to reduce deposition on the
interior plate -while not detrimentally affecting the abatement
treatment in the thermal reaction chamber. Gases contemplated for
passage through the pores of the interior plate 12 include air,
CDA, oxygen-enriched air, oxygen, ozone and inert gases, e.g., Ar,
N.sub.2, etc., and should be devoid of fuels. Further, the fluid
may be introduced in a continuous or a pulsating mode.
[0043] The reticulated ceramic foam interior plate appears to help
prevent particle buildup on the interior plate in part because the
exposed planar surface area is reduced thereby reducing the amount
of surface available for build-up, because the reticulation of the
interior plate provides smaller attachment points for growing
particulate matter which will depart the interior plate upon
attainment of a critical mass and because the air passing through
the pores of the interior plate forms a "boundary layer," keeping
particles from migrating to the surface for deposition thereon.
[0044] Ceramic foam bodies have an open cell structure
characterized by a plurality of interconnected voids surrounded by
a web of ceramic structure. They exhibit excellent physical
properties such as high strength, low thermal mass, high thermal
shock resistance, and high resistance to corrosion at elevated
temperatures. The voids may be uniformly distributed throughout the
material and the voids are of a size that permits fluids to easily
diffuse through the material. The ceramic foam bodies should not
react appreciably with PFC's in the effluent to form highly
volatile halogen species. The ceramic foam bodies may include
alumina materials, magnesium oxide, refractory metal oxides such as
ZrO.sub.2, silicon carbide and silicon nitride, preferably higher
purity alumina materials, e.g., spinel, and yttria-doped alumina
materials. Most preferably, the ceramic foam bodies are ceramic
bodies formed from yttria-doped alumina materials and
yttria-stabilized zirconia-alumina (YZA). The preparation of
ceramic foam bodies is well within the knowledge of those skilled
in the art.
[0045] To further reduce particle build-up on the interior plate
12, a fluid inlet passageway may be incorporated into the center
jet 16 of the inlet adaptor 10 (see for example FIGS. 1, 3 and 5
for placement of the center jet in the inlet adaptor). An
embodiment of the center jet 16 is illustrated in FIG. 4, said
center jet including a pilot injection manifold tube 24, pilot
ports 26, a pilot flame protective plate 22 and a fastening means
28, e.g., threading complementary to threading on the inlet
adaptor, whereby the center jet and the inlet adaptor may be
complementarily mated with one another in a leak-tight fashion. The
pilot flame of the center jet 16 is used to ignite the burner jets
15 of the inlet adaptor. Through the center of the center jet 16 is
a bore-hole 25 through which a stream of high velocity fluid may be
introduced to inject into the thermal reaction chamber 32 (see,
e.g., FIG. 5). It is thought that the high velocity air alters the
aerodynamics and pulls gaseous and/or particulate components of the
thermal reaction chamber towards the center of the chamber thereby
keeping the particulate matter from getting close to the top plate
and the chamber walls proximate to the top plate. The high velocity
fluid may include any gas sufficient to reduce deposition on the
interior walls of the thermal reaction unit while not detrimentally
affecting the abatement treatment in the thermal reaction chamber.
Further, the fluid may be introduced in a continuous or a pulsating
mode, preferably a continuous mode. Gases contemplated include air,
CDA, oxygen-enriched air, oxygen, ozone and inert gases, e.g., Ar,
N.sub.2, etc. Preferably, the gas is CDA and may be
oxygen-enriched. In another embodiment, the high velocity fluid is
heated prior to introduction into the thermal reaction chamber.
[0046] In yet another embodiment, the thermal reaction unit
includes a porous ceramic cylinder design defining the thermal
reaction chamber 32, High velocity air may be directed through the
pores of the thermal reaction unit 30 to at least partially reduce
particle buildup on the interior walls of the thermal reaction
unit. The ceramic cylinder includes at least two ceramic rings
stacked upon one another, for example as illustrated in FIG. 6C.
More preferably, the ceramic cylinder includes at least about two
to about twenty rings stacked upon one another. The term "ring" is
not limited to circular rings per se, but may also include rings of
any polygonal or elliptical shape. Preferably, the rings are
generally tubular in form.
[0047] FIG. 6C is a partial cut-away view of the ceramic cylinder
design showing the stacking of the individual ceramic rings 36
having a complimentary ship-lap joint design, wherein the stacked
ceramic rings define the thermal reaction chamber 32. The uppermost
ceramic ring 40 is designed to accommodate the inlet adaptor. It is
noted that the joint design is not limited to lap joints but may
also include beveled joints, butt joints, lap joints and tongue and
groove joints. Gasketing or sealing means, e.g., GRAFOIL.RTM. or
other high temperature materials, positioned between the stacked
rings is contemplated, especially if the stacked ceramic rings are
butt jointed. Preferably, the joints between the stacked ceramic
rings overlap, e.g., ship-lap, to prevent infrared radiation from
escaping from the thermal reaction chamber.
[0048] Each ceramic ring may be a circumferentially continuous
ceramic ring or alternatively, may be at least two sections that
may be joined together to make up the ceramic ring. FIG. 6A
illustrates the latter embodiment, wherein the ceramic ring 36
includes a first arcuate section 38 and a second arcuate section
40, and when the first and second arcuate sections are coupled
together, a ring is formed that defines a portion of the thermal
reaction chamber 32. The ceramic rings are preferably formed of the
same materials as the ceramic foam bodies discussed previously,
e.g., YZA.
[0049] The advantage of having a thermal reaction chamber defined
by individual stacked ceramic rings includes the reduction of
cracking of the ceramic rings of the chamber due to thermal shock
and concomitantly a reduction of equipment costs. For example, if
one ceramic ring cracks, the damaged ring may be readily replaced
for a fraction of the cost and the thermal reactor placed back
online immediately.
[0050] The ceramic rings are held to another to form the thermal
reaction unit 30 whereby high velocity air may be directed through
the pores of the ceramic rings of the thermal reaction unit to at
least partially reduce particle buildup at the interior walls of
the thermal reaction unit. Towards that end, a perforated metal
shell may be used to encase the stacked ceramic rings of the
thermal reaction unit as well as control the flow of axially
directed air through the porous interior walls of the thermal
reaction unit. FIG. 7 illustrates an embodiment of the perforated
metal shell 110, wherein the metal shell has the same general form
of the stacked ceramic rings, e.g., a circular cylinder or a
polygonal cylinder, and the metal shell includes at least two
attachable sections 112 that may be joined together to make up the
general form of the ceramic cylinder. The two attachable sections
112 include ribs 114, e.g., clampable extensions 114, which upon
coupling put pressure on the ceramic rings thereby holding the
rings to one another.
[0051] The metal shell 110 has a perforated pattern whereby
preferably more air is directed towards the top of the thermal
reaction unit, e.g., the portion closer to the inlet adaptor 10,
than the bottom of the thermal reaction unit, e.g., the lower
chamber (see FIGS. 7 and 8). In the alternative, the perforated
pattern is the same throughout the metal shell. As defined herein,
"perforations" may represent any array of openings through the
metal shell that do not compromise the integrity and strength of
the metal shell, while ensuring that the flow of axially directed
air through the porous interior walls may be controlled. For
example, the perforations may be holes having circular, polygonal
or elliptical shapes or in the alternative, the perforations may be
slits of various lengths and widths. In one embodiment, the
perforations are holes 1/16 '' in diameter, and the perforation
pattern towards the top of the thermal reaction unit has 1 hole per
square inch, while the perforation pattern towards the bottom of
the thermal reaction unit has 0.5 holes per square inch (in other
words 2 holes per 4 square inches). Preferably, the perforation
area is about 0.1% to 1% of the area of the metal shell. The metal
shell is constructed from corrosion-resistant metals including, but
not limited to: stainless steel; austenitic nickel-chromium- iron
alloys such as Inconel.RTM.600, 601, 617, 625, 625 LCF, 706, 718,
718 SPF, X-750, MA754, 783, 792, and HX; and other nickel-based
alloys such as Hastelloy B, B2, C, C22, C276, C2000, G, G2, G3 and
G30.
[0052] Referring to FIG. 8, the ceramic rings 36 are stacked upon
one another, at least one layer of a fibrous blanket is wrapped
around the exterior of the stacked ceramic rings and then the
sections 112 of the metal shell 110 are positioned around the
fibrous blanket and tightly attached together by coupling the ribs
114. The fibrous blanket can be any fibrous inorganic material
having a low thermal conductivity, high temperature capability and
an ability to deal with the thermal expansion coefficient mismatch
of the metal shell and the ceramic rings. Fibrous blanket material
contemplated includes, but is not limited to, spinel fibers, glass
wool and other materials comprising aluminum silicates. In the
alternative, the fibrous blanket may be a soft ceramic sleeve.
[0053] In practice, fluid flow is axially and controllably
introduced through the perforations of the metal shell, the fibrous
blanket and the reticulated ceramic rings of the cylinder. The
fluid experiences a pressure drop from the exterior of the thermal
reaction unit to the interior of the thermal reaction unit in a
range from about 0.05 psi to about 0.30 psi, preferably about 0.1
psi to 0.2 psi. The fluid may be introduced in a continuous or a
pulsating mode, preferably a continuous mode to reduce the
recirculation of the fluid within the thermal reaction chamber. An
increased residence time within the thermal reaction chamber,
wherein the gases are recirculated, results in the formation of
larger particulate material and an increased probability of
deposition within the reactor. The fluid may include any gas
sufficient to reduce deposition on the interior walls of the
ceramic rings while not detrimentally affecting the abatement
treatment in the thermal reaction chamber. Gases contemplated
include air, CDA, oxygen-enriched air, oxygen, ozone and inert
gases, e.g., Ar, N.sub.2, etc.
[0054] To introduce fluid to the walls of the thermal reaction unit
for passage through to the thermal reaction chamber 32, the entire
thermal reaction unit 30 is encased within an outer stainless steel
reactor shell 60 (see, e.g., FIG. 1), whereby an annular space 62
is created between the interior wall of the outer reactor shell 60
and the exterior wall of the thermal reaction unit 30. Fluids to be
introduced through the walls of the thermal reaction unit may be
introduced at ports 64 positioned on the outer reactor shell
60.
[0055] Referring to FIG. 1, interior plate 12 of the inlet adaptor
10 is positioned at or within the thermal reaction chamber 32 of
the thermal reaction unit 30. To ensure that gases within the
thermal reaction unit do not leak from the region where the inlet
adaptor contacts the thermal reaction unit, a gasket or seal 42 is
preferably positioned between the top ceramic ring 40 and the top
plate 18 (see, e.g., FIG. 9). The gasket or seal 42 may be
GRAFOIL.RTM.or some other high temperature material that will
prevent leakage of blow-off air through the top plate/thermal
reaction unit joint, i.e., to maintain a backpressure behind the
ceramic rings for gas distribution.
[0056] Downstream of the thermal reaction chamber is a water
quenching means positioned in the lower quenching chamber 150 to
capture the particulate matter that egresses from the thermal
reaction chamber. The water quenching means may include a water
curtain as disclosed in co-pending U.S. patent application Ser. No.
10/249,703 in the name of Glenn Tom et al., entitled "Gas
Processing System Comprising a Water Curtain for Preventing Solids
Deposition on Interior Walls Thereof," which is hereby incorporated
by reference in the entirety. Referring to FIG. 1, the water for
the water curtain is introduced at inlet 152 and water curtain 156
is formed, whereby the water curtain absorbs the heat of the
combustion and decomposition reactions occurring in the thermal
reaction unit 30, eliminates build-up of particulate matter on the
walls of the lower quenching chamber 150, and absorbs water soluble
gaseous products of the decomposition and combustion reactions,
e.g., C0.sub.2, HF, etc.
[0057] To ensure that the bottom-most ceramic ring does not get
wet, a shield 202 (see, e.g., FIG. 12) may be positioned between
the bottom-most ceramic ring 198 and the water curtain in the lower
chamber 150. Preferably, the shield is L-shaped and assumes the
three-dimensional form of the bottom-most ceramic ring, e.g., a
circular ring, so that water does not come in contact with the
bottom-most ceramic ring. The shield may be constructed from any
material that is water- and corrosion-resistant and thermally
stable including, but not limited to: stainless steel; austenitic
nickel-chromium- iron alloys such as Inconel.RTM.600, 601, 617,
625, 625 LCF, 706, 718, 718 SPF, X-750, MA754, 783, 792, and HX;
and other nickel-based alloys such as Hastelloy B, B2, C, C22,
C276, C2000, G, G2, G3 and G30.
[0058] In practice, effluent gases enter the thermal reaction
chamber 32 from at least one inlet provided in the inlet adaptor
10, and the fuel/oxidant mixture enter the thermal reaction chamber
32 from at least one burner jet 15. The pilot flame of the center
jet 16 is used to ignite the burner jets 15 of the inlet adaptor,
creating thermal reaction unit temperatures in a range from about
500.degree. C. to about 2000.degree. C. The high temperatures
facilitate decomposition of the effluent gases that are present
within the thermal reaction chamber. It is also possible that some
effluent gases undergo combustion/oxidation in the presence of the
fuel/oxidant mixture. The pressure within the thermal reaction
chamber is in a range from about 0.5 atm to about 5 atm, preferably
slightly subatmospheric, e.g., about 0.98 atm to about 0.99
atm.
[0059] Following decomposition/combustion, the effluent gases pass
to the lower chamber 150 wherein a water curtain 156 may be used to
cool the walls of the lower chamber and inhibit deposition of
particulate matter on the walls. It is contemplated that some
particulate matter and water soluble gases may be removed from the
gas stream using the water curtain 156. Further downstream of the
water curtain, a water spraying means 154 may be positioned within
the lower quenching chamber 150 to cool the gas stream, and remove
the particulate matter and water soluble gases. Cooling the gas
stream allows for the use of lower temperature materials downstream
of the water spraying means thereby reducing material costs. Gases
passing through the lower quenching chamber may be released to the
atmosphere or alternatively may be directed to additional treatment
units including, but not limited to, liquid/liquid scrubbing,
physical and/or chemical adsorption, coal traps, electrostatic
precipitators, and cyclones. Following passage through the thermal
reaction unit and the lower quenching chamber, the concentration of
the effluent gases is preferably below detection limits, e.g., less
than 1 ppm.
[0060] In an alternative embodiment, an "air knife" is positioned
within the thermal reaction unit. Referring to FIG. 10, fluid may
be intermittently injected into the air knife inlet 206, which is
situated between the bottom-most ceramic ring 198 and the water
quenching means in the lower quenching chamber 150. The air knife
inlet 206 may be incorporated into the shield 202 which prevents
water from wetting the bottom-most ceramic ring 198 as described.
The air knife fluid may include any gas sufficient to reduce
deposition on the interior walls of the thermal reaction unit while
not detrimentally affecting the decomposition treatment in said
unit. Gases contemplated include air, CDA, oxygen-enriched air,
oxygen, ozone and inert gases, e.g., Ar, N.sub.2, etc. In
operation, gas is intermittently injected through the air knife
inlet 206 and exits a very thin slit 204 that is positioned
parallel to the interior wall of the thermal reaction chamber 32.
Thus, gases are directed upwards along the wall (in the direction
of the arrows in FIG. 10) to force any deposited particulate matter
from the surface of the interior wall.
Improved Reactor Design
[0061] In accordance with the present invention, improvements are
provided to the thermal reaction unit 30 of FIG. 1. For example,
FIG. 11A is a partial cut-away view of the thermal reaction chamber
32 in which the thermal reaction chamber 32 is formed from a
plurality of stacked, porous ceramic sections 36a-h. While eight
stacked, porous ceramic sections are shown in FIG. 11A, it will be
understood that fewer or more than eight stacked sections may be
used. For example, in one particular embodiment, eleven porous
ceramic sections may be used. In some embodiments, more or less
than eleven porous ceramic sections may be used. The ceramic
sections 36a-h may be round, elliptical, triangular, square,
rectangular, polygonal, pentagonal, hexagonal, octagonal, or
otherwise shaped. The ceramic sections may include stackable
washers, chevrons, rings or any other suitable shape and/or
configuration. Rings may be any suitable shape (as described above
such as round, elliptical, polygonal, etc.).
[0062] In one or more embodiments, at least one of the porous
sections may include a non-rigid material. For example, a porous
section may include yttria doped aluminum fiber. As another
example, in some embodiments, at least one of the porous sections
may include a ceramic, a sintered ceramic, a sintered metal, a
porous metal material, doped aluminum fiber, glass and/or a porous
polymeric material.
[0063] In a particular embodiment, at least one of the porous
sections may include MgAI.sub.2O.sub.4, A1.sub.2O.sub.3, SiC,
and/or MgO. A doped ceramic also may be used such as a ceramic
doped with yttria, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er,
Tm, Yb, Lu and/or any other suitable dopant.
[0064] FIG. 11B illustrates an embodiment of the thermal reaction
chamber 32 of FIG. 11A in which each ceramic section 36a-h is
formed from two ceramic subsections 1102a, 1102b. The first ceramic
subsection 1102a is sized so as to fit within and to bond to the
second ceramic subsection 1102b so as to form lap joints 1104a-b.
The lap joints 1104a-b may be used to couple ceramic sections 36a-h
together as shown. Gluing or any other bonding technique may be
used to couple ceramic subsections 1102a, 1102b together. Use of
such bonded ceramic sections may reduce manufacturing costs.
[0065] In at least one embodiment, the thermal reaction chamber 32
may have a graded and/or varying coefficient of thermal expansion
(CTE). For example, the ceramic sections closest to the inlets of
the reaction chamber 32 (the top of the reaction unit in FIG. 11A)
may have a smaller CTE than the ceramic sections further from the
inlets. In one particular embodiment, the first ceramic section 36a
(closest to the inlets) may have the smallest CTE and the eighth
ceramic section 36h (furthest from the inlets) may have the largest
CTE. The remaining ceramic sections 36b-g may have CTE's that range
from, and in some embodiments decrease in value from, the highest
CTE and the lowest CTE. The above embodiment may provide a cost
savings for the thermal reaction chamber 32 as more expensive,
lower CTE ceramics may be used close to the inlets of the reaction
chamber 32 (e.g., where temperatures are the highest), and cheaper,
higher CTE ceramics may be used in regions of the reaction chamber
32 that are subjected to lower temperatures.
[0066] In the same or another embodiment, higher quality ceramics,
such as 99.99% A1203, that are more temperature and/or chemical
resistant may be used for the ceramic section or sections closest
to the inlets of the thermal reaction chamber 32, while lower
quality ceramics, such as 98% A1203, may be used for the ceramic
sections further from the inlets of the thermal reaction chamber
32.
[0067] In the same or another embodiment, the CTE of each ceramic
section may be graded or otherwise vary. For example, the CTE of a
ceramic section may be graded so that portions of the ceramic
section that experience the highest temperatures have the lowest
CTE. In the embodiment of FIG. 11A, for instance, each ceramic
section may have a graded CTE that decreases from the top to the
bottom of the ceramic section and/or from the inside to the outside
of the ceramic section.
[0068] In the same or another embodiment, the porosity,
composition, dopant type and/or concentration, etc., of each
ceramic section and/or between ceramic sections may be graded
and/or vary. Likewise, the pores may vary in size, shape, density,
etc., within a ceramic section and/or between ceramic sections.
Also, the pores may be uniform in shape, tapered (e.g., with a
larger opening on the inside or the outside of a section), or
otherwise shaped. Multiple pore sizes may be used within a ceramic
section (e.g., pores 2, 3, 4, etc., different diameters).
[0069] In one or more embodiments, a first porous section may have
a first doping level and a second porous section may have a second,
different doping level. For example, higher dopant level porous
sections may be used closest to the inlets of a thermal reaction
chamber. In some embodiments, at least one of a CTE, a purity level
and a doping level of each porous section may be selected based on
a temperature profile within a thermal reaction unit during
abatement. Further, at least one of a CTE, a purity level and a
doping level of each porous section may be selected so that
expansion of each porous section is approximately equal within the
thermal reaction unit during abatement. In one or more embodiments,
each ceramic ring may have a different CTE, purity level and/or
dopant level.
[0070] In yet other embodiments, one or more of the ceramic
sections may include or be adapted to accommodate and/or facilitate
the use of one or more sensors (e.g., by having a void or other
space for one or more sensors). For example, one or more ceramic
sections may include a temperature, NOX, pressure, radiation or
other suitable sensor. One or more such sensors may be coupled to a
controller and used to provide better control over or monitoring of
an abatement process within the thermal reaction chamber 32 (e.g.,
via a feedback loop that allows adjustment of flow rates, gas
concentrations, etc.). One or more ceramic sections alternatively
or additionally may include one or more ports that allow gas to be
flowed through the ceramic sections (e.g., during a purge
operation) and/or that allow gas to be extracted from the thermal
reaction chamber 32 (e.g., via a sampling operation). For example,
periodic or random sampling of reaction gases and/or products may
be performed through a port within a ceramic section (to allow
analysis of a combustion process).
[0071] FIG. 12 is a schematic diagram of an exemplary thermal
reaction chamber 1200 defined by a plurality of ceramic sections
1202a-f. Fewer or more ceramic sections may be used. Each ceramic
section 1202a-f includes a port 1204a-f for purging and/or sampling
the chamber 1200. Additionally, each ceramic section 1202a-f
includes a sensor 1206a-f for sensing a characteristic of the
chamber 1200 (e.g., temperature, NOX level, etc.). Each port
1204a-f and/or sensor 1206a-f may be in communication with and/or
controlled via a controller 1208. The controller 1208 may include,
for example, one or more microcontrollers, microprocessors,
dedicated hardware, a combination of the same, etc. In at least one
embodiment, the controller 1208 may use information gathered from
the ports 1204a-f and/or sensors 1206a-f to control process
parameters associated with the thermal reaction chamber 1200 (e.g.,
flow rates, gas concentrations, etc.).
[0072] In one or more embodiments, multiple processing tools (e.g.,
cluster or similar tools) may be abated using a single thermal
abatement system, such as the thermal reaction chamber 30 and/or
quenching unit 150. For example, 2, 3, 4, 5, 6, etc., processing
tools may be so abated. Likewise, multiple thermal abatement
systems may service that same tool (e.g., for redundancy). For
example, two of the thermal abatement systems described herein may
be used to abate three or more processing tools. In this manner,
each processing tool includes a redundant abatement system yet
fewer than one abatement system per processing tool is required.
Other similar configurations may be used (e.g., 3 abatement systems
servicing 4, 5, 6, etc., processing tools). Additional inlets may
be provided for each abatement system as required to service
multiple processing tools (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.,
inlets). Also, multiple abatement systems may service a single tool
(e.g., 2, 3, 4, 5, etc., abatement systems per tool). Thus, the
system may be configured with multiple processing tools serviced by
multiple thermal abatement chambers; multiple processing tools
serviced by a single thermal abatement chamber; and/or a single
processing tool serviced by multiple thermal abatement chambers. In
some embodiments where the capacity of the thermal abatement
chambers exceeds the pollutant output load, one or more thermal
abatement chambers may serve as secondary or back-up abatement
chambers that are not used unless a primary thermal abatement
chamber goes offline. In such embodiments, a manifold may be used
to selectively direct the waste to the active abatement chambers
and away from the inactive chambers. The manifold may be operated
under control of a system controller and may respond to feedback
from the abatement chambers and/or information about the quantity
and composition of the waste flow from the possessing tools and/or
sensors in or upstream of the manifold.
[0073] FIG. 13 is a top view of an exemplary embodiment of the
thermal reaction unit 30 in which inlet ports 14 to the reaction
chamber 32 are angled (e.g., relative to vertical) so as to direct
effluent and/or other gasses away from inner wall 1300 of the
reaction chamber 32 toward a central reaction zone 1302. The inlet
ports 14 also may be angled to create a turbulent and/or swirling
combustion zone as shown. Exemplary angles for the inlet ports
include 2 to 45 degrees from vertical, although other angles may be
used. The inlet ports may be angled to direct the waste in a
helical vortex pattern that maximizes the residence time of the
waste in the reaction chamber to increase the combustion of all the
waste. In some embodiments, the angle of the inlet ports 14 may be
adjustable based upon the desired helical vortex pattern for a
given type of waste. For example, certain waste may benefit from a
longer residence time while other types may not require a longer
residence time and may be combusted most efficiently when
introduced at a steeper (e.g., more downward) angle. The angle of
the inlet ports 14 may be controlled by a system controller based
upon feedback from the processing tools, sensors (e.g.,
temperature, pressure, flow, composition, etc.) in the manifold,
and/or sensors in the reaction chamber 32. The angle of the inlet
ports 14 may be selected based upon sensor information or known
information about the waste itself (e.g., quantity, composition,
etc.) and/or the processes that generated the waste.
[0074] In some embodiments, the perforations in the metal shell
provide a pressure drop across the thermal reaction unit of about
0.1 to about 5 psi. In one embodiment, about 22 stacked ceramic
rings may be employed for the chamber 32.
[0075] A two-stage reactor for removing pollutants from gaseous
streams may include an upper thermal reaction chamber and a lower
reaction chamber. The upper thermal reaction chamber may include an
outer exterior wall, an interior porous wall that defines a central
decomposition and conversion chamber, at least one waste gas inlet
in fluid communication with the central decomposition and
conversion chamber for introducing a gaseous waste stream therein,
thermal means for decomposing and converting the gaseous waste
stream into reaction products, and means for introducing a fluid
into the interior space. The interior porous wall may be adapted to
allow transference of the fluid from the interior space into the
central decomposition and conversion chamber at a sufficient force
to reduce deposition of reaction products on the interior porous
wall. The interior porous wall may also be positioned from the
outer exterior wall a sufficient distance to define an interior
space.
[0076] The lower reaction chamber may include a gas flow chamber in
fluid communication with the central decomposition and conversion
chamber. The gas flow chamber may include an inlet and an outlet
for passing the gaseous waste stream and reaction products
therethrough. The lower reaction chamber may also include means for
generating a downwardly flowing liquid film on interior surfaces of
the gas flow chamber. The downwardly flowing liquid film may reduce
deposition and accumulation of particulate solids on the lower
reaction chamber. In some embodiments, a water fall and/or spray
jets may be employed to create the downwardly flowing liquid
film.
[0077] The interior space positioned between the outer exterior
wall and the interior porous wall may be an interior annular space.
The means for introducing a fluid into the interior space may be
adapted to introduce pressurized fluid into the interior annular
space. The means for introducing a fluid into the interior space
may be adapted to introduce water, steam, air, clean dry air, clean
enriched air, oxygen enriched air, oxygen depleted air (e.g., air
with a lower than atmospheric percentage of oxygen), inert gas
(e.g., N.sub.2), depleted air or inert gas, and/or mixtures
thereof. The means for introducing a fluid into the interior space
may alternatively be adapted to introduce water alone or air alone.
In some embodiments, the means for introducing a fluid into the
interior space may be adapted to introduce fluid into the interior
space under pulsing conditions. The means for introducing a fluid
into the interior space may also be adapted to inject fluid into
the central decomposition and conversion chamber under periodic
pulsing. In some embodiments, the pulsing conditions may use a
pulsation duration of from about 3 ms to 1 second.
[0078] The two-stage reactor may be adapted such that the lower
reaction chamber includes at least one oxidant inlet positioned to
introduce an oxidant to the gas flow chamber. The two-stage reactor
may also include at least one additional gas inlet for introducing
a combustible fuel, reactants, and/or an oxidant for mixing with
the gaseous waste stream. The reactor may also include a
combustible fuel supply coupled to the at least one additional gas
inlet, wherein the combustible fuel supply is adapted to supply
oxygen, city gas, LPG, propane, methane, and/or hydrogen.
[0079] In some embodiments, the means for introducing a fluid into
the interior space includes a liquid vortex positioned near the
inlet of the gas flow chamber. The liquid vortex may include an
outer shell having a top plate with a central opening in fluid
communication with the central decomposition and conversion
chamber. There may be a conical-shaped baffle within the outer
shell having an inner surface and a central opening which is
generally aligned with the interior surface of the gas stream flow
chamber. The conical-shaped baffle may be generally concentrically
aligned with the inner surface of the outer shell to form a
concentric chamber. The liquid vortex may also include a liquid
inlet arranged to tangentially introduce liquid into the concentric
chamber. The liquid may be introduced such that the concentric
chamber is filled with liquid to create a swirling motion so that
the liquid rises and overflows the conical-shaped baffle and forms
a sheet of fluid on the inner surface of the conical-shaped baffle
that flows downwardly onto the interior surface of the gas stream
flow chamber. The sheet of fluid on the inner surface of the
conical-shaped baffle may inhibit an entering gas stream from
contacting the interior surface of the gas stream flow chamber
thereby resisting deposition of reaction products thereon.
[0080] In some embodiments, the interior porous wall may be
fabricated of a material that includes ceramic, sintered ceramic,
sintered metal, porous metal material, a porous polymeric material,
glass, and/or blends and/or combinations thereof. The interior
porous wall may include pores uniformly distributed in the porous
material. In other embodiments, the pores may be distributed with a
varying density including on a gradient.
[0081] In some embodiments, the outer exterior wall and the
interior porous wall may be separated by a sufficient distance to
provide an annular space and for distributing a pressured gas for
passage through the interior porous wall. The reaction chamber may
operate at a pressure that is lower than atmospheric pressure.
[0082] The interior porous wall may include a plurality of
apertures for passage of a pressurized gas through the interior
porous wall into the central decomposition and conversion chamber.
The plurality of apertures may include conical shaped
protuberances.
[0083] The means for introducing a fluid into the interior space
may be adapted to introduce fluid that is compressed to a suitable
pressure to facilitate pulsating ejection of the fluid with a force
sufficient to reduce particle deposition on the inner surface of
the central decomposition and conversion chamber. In some
embodiments, the pressure may be from about 60 psig to about 100
psig.
[0084] In some embodiments, the invention may include an abatement
system for controlled decomposition and conversion of gaseous
pollutants in a gaseous waste stream. The system may include an
upper thermal reaction chamber and a lower reaction chamber. The
upper thermal reaction chamber may include an outer exterior wall,
an interior porous wall that defines a central decomposition and
conversion chamber, means for introducing a fluid to the interior
annular space, thermal means for decomposing and converting the
gaseous waste stream to form reaction products, and at least one
waste gas inlet for conducting the gaseous waste stream into the
upper thermal reactor. The interior porous wall may be positioned
from the outer exterior wall a sufficient distance to define an
interior annular space.
[0085] The lower reaction chamber may include a gas flow chamber in
fluid communication with the central decomposition and conversion
chamber, and at least one oxidant inlet positioned to introduce an
oxidant to the gas stream flow chamber.
[0086] The waste gas inlet may include a conduit that terminates
within the central decomposition and conversion chamber. The
portion of the conduit that terminates within the central
decomposition and conversion chamber may be located within a tube
which projects beyond the end of the conduit to define a chamber
within the tube for flame formation. The tube may have an open end
in fluid communication with the central decomposition and
conversion chamber.
[0087] The lower reaction chamber may include a liquid vortex
positioned between the central decomposition and conversion chamber
and the gas flow chamber. The liquid vortex may include an outer
shell with a top plate, a conical-shaped baffle within the outer
shell, and a liquid inlet. The outer shell may include a central
opening in fluid communication with the central decomposition and
conversion chamber. The conical-shaped baffle within the outer
shell may include an inner surface and a central opening which is
generally aligned with the interior surface of the gas stream flow
chamber. The conical-shaped baffle may generally be concentrically
aligned with the inner surface of the outer shell to form a
concentric chamber. The liquid inlet may be arranged to
tangentially introduce liquid into the concentric chamber. The
liquid may be introduced so as to fill the concentric chamber with
liquid, creating a swirling motion, and causing the liquid to rise
and overflow the conical-shaped baffle into the gas stream flow
chamber. The overflowing liquid may thus form a sheet of fluid on
the inner surface of the conical-shaped baffle that flows
downwardly onto the interior surface of the gas stream flow
chamber.
[0088] The interior porous wall may provide for transference of the
fluid from the interior annular space into the central
decomposition and conversion chamber at a sufficient force to
reduce deposition of reaction products on the interior porous wall.
The interior porous wall may have a porosity of less than about
20%.
[0089] In some embodiments, the means for introducing a fluid to
the interior annular space may be adapted to introduce pressurized
fluid into the annular space. The means for introducing a fluid may
be adapted to introduce fluid including water, steam, air, clean
dry air, clean enriched air, oxygen enriched air, oxygen depleted
air (e.g., air with a lower than atmospheric percentage of oxygen),
inert gas (e.g., N.sub.2), depleted air or inert gas, and/or
mixtures thereof. The means for introducing a fluid into the
interior space may alternatively be adapted to introduce water
alone or air alone. For example, the means for introducing a fluid
to the interior annular space may be adapted to inject steam
through the interior porous wall. In addition, the means for
introducing a fluid to the interior annular space may be adapted to
introduce fluid under pulsing conditions.
[0090] In some embodiments, a fluid deliver system or other means
for introducing a fluid to the interior annular space may be
adapted to provide at least one of water, steam, air, clean dry
air, clean enriched air, oxygen enriched air, oxygen depleted air,
inert gas, a reagent, an oxidizer and depleted air. In one or more
embodiments, the fluid delivery system or other means may be
adapted to provide at least one of ozone, hydrogen peroxide and
ammonia.
[0091] The abatement system may further include one or more
additional gas inlets for introducing a combustible fuel,
reactants, and/or an oxidant for mixing with the gaseous waste
stream. The abatement system may also include a combustible fuel
supply coupled to the at least one additional gas inlet. The
combustible fuel supply may be adapted to supply oxygen, butane,
ethanol, LPG, city gas, natural gas, propane, methane, hydrogen,
13A and/or mixtures thereof.
[0092] The invention may also include methods for controlled
decomposition and conversion of gaseous pollutants in a gaseous
waste steam in a two-stage thermal reactor. The methods may include
introducing the gaseous waste stream to an upper thermal reactor
through at least one waste gas inlet, providing at least one
combustible fuel for mixing with the gaseous waste stream to form a
fuel rich combustible gas stream mixture, igniting the fuel rich
combustible gas stream mixture in a decomposition and conversion
chamber to effect formation of reaction products, injecting an
additional fluid into the decomposition and conversion chamber
through a porous wall of the decomposition and conversion chamber
contemporaneously with the decomposing and converting of the fuel
rich combustible gas stream mixture, wherein the additional fluid
is injected at a force exceeding that of reaction products
approaching an interior surface of the decomposition and conversion
chamber thereby inhibiting deposition of the reaction products
thereon, flowing the reaction products into a lower reaction
chamber, flowing water along a portion of an interior surface of
the lower reaction chamber, and flowing the reaction products
through the portion of the lower reaction chamber, wherein the
flowing water inhibits deposition of the reaction products on the
interior surface of the lower reaction chamber.
[0093] In some embodiments, injecting an additional fluid into the
decomposition and conversion chamber through a porous wall of the
decomposition and conversion chamber may include pulsing the
additional fluid through the porous wall. The methods may further
include introducing an air containing gas into the reaction
products so as to form a fuel lean mixture. Flowing water along a
portion of an interior surface of the lower reaction chamber may
include employing a water vortex.
[0094] The invention may further include an apparatus for use
during the abatement of a semiconductor manufacturing process. The
apparatus may include a thermal reaction chamber with an interior
porous wall that defines a central decomposition and conversion
chamber, at least one waste gas inlet in fluid communication with
the central decomposition and conversion chamber and adapted to
introduce a gaseous waste stream to the central decomposition and
conversion chamber, a thermal mechanism positioned within the
central decomposition and conversion chamber and adapted to combust
the gaseous waste stream within the central decomposition and
conversion chamber, thereby forming reaction products; and a fluid
delivery system adapted to provide a fluid to the central
decomposition and conversion chamber through the interior porous
wall at a sufficient force to reduce deposition of reaction
products on an inner surface of the interior porous wall of the
central decomposition and conversion chamber.
[0095] The apparatus may further include an outer wall that
surrounds the interior porous wall and that defines an interior
space between the outer wall and the interior porous wall. The
fluid delivery system may be adapted to provide a fluid to the
central decomposition and conversion chamber through the interior
porous wall by providing fluid to the interior space between the
outer wall and the interior porous wall. The central decomposition
and conversion chamber may be cylindrical. The fluid delivery
system may be adapted to provide water, air, clean dry air,
depleted air and/or clean enriched air to the central decomposition
and conversion chamber through the interior porous wall. The fluid
delivery system may also be adapted to provide fluid to the central
decomposition and conversion chamber through the interior porous
wall by pulsing the fluid. The pulsing may be periodic. The fluid
delivery system may be adapted to provide fluid to the central
decomposition and conversion chamber through the interior porous
wall at a pressure of less than about 600 psig and, in some
embodiments, at a pressure less than about 100 psig. In some
embodiments, the fluid delivery system may be adapted to provide a
fluid at a pressure of about 50 psig to about 100 psig, about 5
psig to about 50 psig, or about 1/10 psig to about 5 psig. Other
pressure ranges may be used.
[0096] The fluid delivery system may be adapted to provide a fluid
to the central decomposition and conversion chamber through the
interior porous wall so as to form a non-deposition zone adjacent
the interior surface of the central decomposition and conversion
chamber. The fluid delivery system may also include a plurality of
inlets adapted to deliver fluid along a length of an exterior
surface of the interior porous wall.
[0097] The interior porous wall may include pores shaped so as to
provide passage of fluid into the central decomposition and
conversion chamber while reducing backflow of any fluid or reaction
products from the central decomposition and conversion chamber. In
some embodiments, the interior porous wall may include a porous
ceramic. The wall may include pores shaped so as to provide passage
of fluid into the central decomposition and conversion chamber
while reducing backflow of any fluid or reaction products from the
central decomposition and conversion chamber.
[0098] The thermal reaction chamber may include a plurality of
waste gas inlets. For example, the thermal reaction chamber may
include at least four or six waste gas inlets. The inlets may be
angled and/or directed so as to introduce turbulent flow to prevent
deposition on the sidewalls of the chamber.
[0099] The apparatus may further include a second reaction chamber
coupled to the thermal reaction chamber. The second reaction
chamber may include a gas flow chamber in fluid communication with
the central decomposition and conversion chamber. The gas flow
chamber may have an inlet and outlet for passing the gaseous waste
stream and reaction products through the gas flow chamber. In some
embodiments, the second reaction chamber may also include a water
delivery system adapted to generate a flowing liquid film on an
interior surface of the gas flow chamber so as to reduce deposition
and accumulation of particulate solids on the interior surface of
the gas flow chamber.
[0100] The water delivery system may be adapted to cool the
interior surface of the gas flow chamber. In some embodiments, the
water delivery system may be adapted to generate a vortex of
cooling water. In some embodiments, the second reaction chamber may
be located below the thermal reaction chamber. The second reaction
chamber may also include at least one inlet adapted to introduce an
oxidant to the gaseous waste stream.
[0101] The invention may be embodied as an apparatus for use during
the abatement of a semiconductor manufacturing process. The
apparatus may include an upper reaction chamber and a lower
reaction chamber. The upper reaction chamber may include an
interior porous wall that defines a central decomposition and
conversion chamber, an outer wall that surrounds the interior
porous wall and that defines an interior space between the outer
wall and the interior porous wall, at least one waste gas inlet in
fluid communication with the central decomposition and conversion
chamber and adapted to introduce a gaseous waste stream to the
central decomposition and conversion chamber, a thermal mechanism
positioned within the central decomposition and conversion chamber
and adapted to combust the gaseous waste stream within the central
decomposition and conversion chamber to thereby form reaction
products, and a fluid delivery system adapted to provide a fluid to
the central decomposition and conversion chamber through the
interior porous wall at a sufficient force to reduce deposition of
reaction products on an inner surface of the interior porous wall
of the central decomposition and conversion chamber.
[0102] The lower reaction chamber may be coupled to the upper
reaction chamber. The lower reaction chamber may include a gas flow
chamber in fluid communication with the central decomposition and
conversion chamber, the gas flow chamber having an inlet and outlet
for passing the gaseous waste stream and reaction products through
the gas flow chamber. The lower reaction chamber may also include a
water delivery system adapted to generate a flowing liquid film on
an interior surface of the gas flow chamber so as to reduce
deposition and accumulation of particulate solids on the interior
surface of the gas flow chamber. The lower reaction chamber may
also include an inlet adapted to introduce an oxidant to the
gaseous waste stream.
[0103] The invention may also include a replaceable liner for a
thermal reaction chamber. The replaceable liner may be modular,
porous, and constructed of ceramic or other similar materials. The
porous ceramic liner may have a shape that defines a central
decomposition and conversion chamber for use during decomposition
and conversion of gaseous waste from a semiconductor manufacturing
process. The porous ceramic liner or wall may have sufficient
porosity to allow transfer of fluid from outside the porous ceramic
wall, through the porous ceramic wall, and into the central
decomposition and conversion chamber during a decomposition and
conversion process performed within the central decomposition and
conversion chamber so as to reduce movement of reaction products
toward an interior surface of the porous ceramic wall or liner.
[0104] In some embodiments, the porous ceramic wall/liner may
include pores shaped so as to provide passage of fluid into the
central decomposition and conversion chamber defined by the porous
ceramic wall while reducing backflow of any fluid or reaction
products from the central decomposition and conversion chamber. The
porous ceramic wall may include ceramic, sintered ceramic,
MgAI.sub.2O.sub.4, A1.sub.2O.sub.3, SiC, MgO, and/or any
combination thereof.
[0105] The invention may alternatively include a porous material
wall having a shape that defines a central decomposition and
conversion chamber for use during decomposition and conversion of
gaseous waste from a semiconductor manufacturing process. The
porous material wall may have sufficient porosity to allow transfer
of fluid from outside the porous material wall through the porous
material wall and into the central decomposition and conversion
chamber during a decomposition and conversion process performed
within the central decomposition and conversion chamber so as to
reduce movement of reaction products toward an interior surface of
the porous material wall. The porous material wall may comprise a
sintered ceramic, sintered metal, porous metal material, a porous
polymeric material, and/or a combination thereof.
[0106] Although the invention has been variously described herein
with reference to illustrative embodiments and features, it will be
appreciated that the embodiments and features described hereinabove
are not intended to limit the invention, and that other variations,
modifications and other embodiments will readily suggest themselves
to those of ordinary skill in the art, based on the disclosure
herein. The invention therefore is to be broadly construed,
consistent with the claims hereafter set forth.
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