U.S. patent application number 12/022150 was filed with the patent office on 2008-06-12 for low pressure drop canister for fixed bed scrubber applications and method of using same.
This patent application is currently assigned to Applied Materials, Inc.. Invention is credited to John Michael Sherer.
Application Number | 20080134887 12/022150 |
Document ID | / |
Family ID | 33158337 |
Filed Date | 2008-06-12 |
United States Patent
Application |
20080134887 |
Kind Code |
A1 |
Sherer; John Michael |
June 12, 2008 |
Low pressure drop canister for fixed bed scrubber applications and
method of using same
Abstract
An apparatus and method for abating toxic and/or hazardous gas
species in a diluent gas stream line deriving from a by-pass line
of a semiconductor process tool, comprising contacting the diluent
gas stream with a dry resin sorbent material having an affinity for
the toxic and/or hazardous gas species to effect the removal of at
least a portion of the toxic and/or hazardous gas species by a
chemisorbent or physisorbent reaction between the sorbent bed and
the toxic gas component effectively reduces the concentration of
the toxic gas component in the process diluent stream to below
TLV.
Inventors: |
Sherer; John Michael;
(Gilbert, AZ) |
Correspondence
Address: |
DUGAN & DUGAN, PC
245 Saw Mill River Road, Suite 309
Hawthorne
NY
10532
US
|
Assignee: |
Applied Materials, Inc.
|
Family ID: |
33158337 |
Appl. No.: |
12/022150 |
Filed: |
January 29, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11014643 |
Dec 16, 2004 |
7323042 |
|
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12022150 |
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10249506 |
Apr 15, 2003 |
6843830 |
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11014643 |
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Current U.S.
Class: |
95/116 ; 96/108;
96/112 |
Current CPC
Class: |
B01D 2253/206 20130101;
B01D 53/04 20130101; B01D 53/75 20130101; B01D 2258/0216 20130101;
C23C 16/4412 20130101; B01D 2253/112 20130101; B01D 53/0423
20130101; B01D 2259/4148 20130101; B01D 53/02 20130101; B01D
53/0446 20130101 |
Class at
Publication: |
95/116 ; 96/108;
96/112 |
International
Class: |
B01D 53/14 20060101
B01D053/14 |
Claims
1. A point-of-use scrubber for treating a toxic and/or hazardous
component in an effluent waste stream deriving from a by-pass line
of a semiconductor process tool, said scrubber comprising a
canister having: an inlet in gas flow communication with the
process tool's bypass line; an outlet; and a sorbent bed
therebetween; wherein said sorbent bed contacts the toxic and/or
hazardous component in the effluent waste stream to effectively
reduce the concentration therein of the toxic and/or hazardous
component.
2. The scrubber of claim 1, wherein said canister is of an up-flow
design.
3. The scrubber of claim 1, wherein said canister is of a cubic
geometry.
4. The scrubber of claim 1, wherein said canister has a volume that
is between 0.1 to 1000 liters.
5. The scrubber of claim 1, wherein said canister has a volume that
is between 4 and 50 liters.
6. The scrubber of claim 1, having a zero footprint.
7. The scrubber of claim 1, wherein said canister is of an up-flow
design and of a cubic geometry.
8. The scrubber of claim 2, wherein said up-flow canister further
comprises at least a lower plenum space section and an upper plenum
space section.
9. The scrubber of claim 8, wherein said sorbent bed resides in a
section that is between said lower and upper plenum space
sections.
10. The scrubber of claim 8, wherein said lower plenum space
section is in gas flow communication with said canister inlet.
11. The scrubber of claim 8, wherein said upper plenum space is in
gas flow communication with said canister outlet.
12. The scrubber of claim 1, wherein said by-pass line comprises a
mass flow controller.
13. The scrubber of claim 12, wherein said mass flow controller is
upstream of said semiconductor process tool.
14. The scrubber of claim 1, wherein said by-pass line is coupled
to at least one of: a point-of-use house abatement system,
atmosphere, a vent and a roof of a semiconductor facility.
15. The scrubber of claim 1, wherein said toxic and/or hazardous
component is selected from the group consisting of arsine,
phosphine and germane.
16. The scrubber of claim 1, wherein said effluent waste stream
further comprises a diluent gas.
17. The scrubber of claim 1, wherein said sorbent bed is of a dry
resin material.
18. The scrubber of claim 17, wherein said dry resin material
comprises at least one metal oxide.
19. The scrubber of claim 17, wherein said dry resin material
comprises at least one component selected from the group consisting
of: carbon, CuSO.sub.4, Cu(OH.sub.2), CuO, CuCO.sub.3,
CuCO.sub.3.Cu(OH).sub.2, Cu.sub.2O, MnO.sub.x, wherein x is from 1
to 2 inclusive, AgO, Ag.sub.2O, CoO, CO.sub.3O.sub.4,
Cr.sub.2O.sub.3, CrO.sub.3, MoO.sub.2, MoO.sub.3, TiO.sub.2, NiO,
LiOH, Ca(OH).sub.2, CaO, NaOH, KOH, Fe.sub.2O.sub.3, ZnO,
Al.sub.2O.sub.3, K.sub.2CO.sub.3, KHCO.sub.3, Na.sub.2CO.sub.3,
NaHCO.sub.3, NH.sub.3OH, Sr(OH).sub.2, HCOONa, BaOH, KMnO.sub.4,
SiO.sub.2, ZnO, MgO, Mg(OH).sub.2, Na.sub.2O.sub.3S.sub.2,
SiO.sub.2, triethylenediamine (TEDA) and mixtures thereof.
20. The scrubber of claim 17, wherein said dry resin material
comprises at least one component selected from the group consisting
of: CuSO.sub.4, Cu(OH.sub.2), CuO, CuCO.sub.3,
CuCO.sub.3.Cu(OH).sub.2, Cu.sub.2O, MnO.sub.x, wherein x is from 1
to 2 inclusive, Ca(OH).sub.2, and CaO.
21. The scrubber of claim 1, further comprising at least one of: an
end point monitor, a pressure sensor and a temperature sensor.
22. An abatement apparatus for reducing the concentration of a
toxic and/or hazardous component, in a by-pass line of an epitaxial
deposition reactor, the apparatus comprising an up-flow
canister.
23. A point-of-use, scrubber for treating an effluent waste stream
comprising a toxic and/or hazardous component, said waste stream
deriving from a by-pass line of a semiconductor process, said
scrubber comprising: an up-flow canister comprising: a lower
section plenum space; an upper section plenum space; at least one
dry resin sorbent bed layer therebetween an inlet in gas flow
communication with the by-pass process line; and an outlet,
arranged such that the process effluent waste stream flows in an
upward direction to effectively reduce the concentration of the
toxic/and or hazardous component from the effluent waste
stream.
24. A process for reducing the concentration of a toxic and/or
hazardous component in a diluent waste stream deriving from a
by-pass line of semiconductor process tool, said process
comprising, contacting the diluent gas stream with a dry resin
sorbent material having an affinity for the toxic and/or hazardous
component, to effect the removal of at least a portion of the toxic
and/or hazardous component by a chemisorbent or physisorbent
reaction between the sorbent material and the toxic gas component
in the process diluent waste stream to below TLV.
Description
[0001] This application is a continuation of and claims priority to
U.S. patent application Ser. No. 11/014,643 filed Dec. 16, 2004,
which is a divisional of U.S. patent application Ser. No.
10/249,506 filed Apr. 15, 2003, issued as U.S. Pat. No. 6,843,830,
which is hereby incorporated by reference herein in its
entirety.
BACKGROUND
[0002] Embodiments described relate to dry resin sorbent systems in
a by-pass line of a semiconductor process tool useful for reducing
toxic and/or hazardous gaseous components deriving therefrom.
BACKGROUND OF THE RELATED ART
[0003] Typical and emerging semiconductor Epitaxial (EPI) processes
use toxic and/or hazardous source gases such as arsine (AsH.sub.3),
phosphine (PH.sub.3), germane (GeH.sub.4) and diborane
(B.sub.2H.sub.6) for deposition of hetero-epitaxial thin films.
Many of these processes are equipped with point-of use (POU) water
scrubbers, which are designed to abate specific gases used in such
processes, such as dichlorosilane (SiH.sub.2Cl.sub.2). However, wet
scrubbers are ineffective at abating many hydride gases such as
AsH.sub.3 and PH.sub.3. If a point-of-use water scrubber is used,
the unabated hydride gases may be released to the roof, where they
can be further re-entrained into the semiconductor facility through
make up air fans.
[0004] These toxic and/or hazardous gases are typically diluted
with hydrogen when fed to EPI reactors, many of which continuously
by-pass some of that gas to "equalize" pressure/flow to the
reactor. By such design, during deposition, only a small amount of
hydride gas flows to the reactor, while a much larger amount
bypasses the chamber and goes directly to vent. The by-pass can go
to outside air directly or to a POU abatement system on the EPI
reactor.
[0005] Many EPI processes feed hydride gases in ppm levels and mass
flow controllers are typically used to control their flow. The
hydride gas may be used in combination with diluents and/or are
combined therewith in a mixing manifold up-stream of a mass-flow
controller. Pressure in the manifold is maintained at a constant
level by pressure controllers, transducers etc.
[0006] It is plausible to use a thermal oxidizer in the bypass line
to reduce the occurrence of hydride gas components being released
to the environment or ventilation system. However, if the hydride
gas component in the bypass line is, for example, arsine,
arsenic-containing waste is generated, which must be handled and
treated carefully as arsenic is highly toxic. Further, a high cost
of ownership is associated with thermal oxidizers, particularly in
the area of fuel consumption.
[0007] Alternatively a combination thermal/wet scrubber may be used
in the bypass line to reduce the occurrence of hydride gas
components being released to the environment or ventilation system.
However, if arsenic is present in the by-pass line,
arsenic-containing by-products will become entrained in the
wastewater. The arsenic-contaminated water is highly controlled in
certain areas of the United States and will likely require further
treatment prior to disposal. Moreover, initial costs of such a
system start in a six-digit dollar range and maintenance and
operational costs are predicted to start in a five-digit dollar
range.
[0008] Therefore, it is one objective of the present invention, to
provide an inexpensive solution to controlling the release of
hazardous and/or toxic gas components from a bypass line upstream
of a semiconductor process tool.
[0009] It is a further objective of the present invention to
provide an inexpensive solution to controlling the release of
hazardous and/or toxic gas components from a point-of-use water
scrubber.
SUMMARY OF THE INVENTION
[0010] The present invention provides a by-pass abatement system
and process for removing pollutants from a by-pass effluent gaseous
stream, which is preferably derived from a semiconductor process
tool.
[0011] In one aspect, the present invention relates to an abatement
apparatus and system for use in a by-pass process line originating
from a semiconductor process.
[0012] In a further aspect, the invention relates to an abatement
apparatus, comprising a sorbent-based scrubber, which when joined
in fluid flow communication with an effluent gas stream comprising
a hazardous component, reduces the concentration of the hazardous
component in the effluent gas stream.
[0013] In a still further aspect, the present invention relates to
a point-of-use scrubber for treating a toxic and/or hazardous
component in an effluent waste stream deriving from a by-pass line
of a semiconductor process tool, said scrubber comprising a
canister having:
[0014] an inlet in gas flow communication with the process tool's
bypass line;
[0015] an outlet; and
[0016] a sorbent bed therebetween;
wherein said sorbent bed contacts the toxic and/or hazardous
component in the effluent waste stream to effectively reduce the
concentration therein of the toxic and/or hazardous component.
[0017] In a still further aspect, the present invention relates to
an abatement apparatus for reducing the concentration of a toxic
and/or hazardous component, in a by-pass line of an epitaxial
deposition reactor, the apparatus comprising an up-flow
canister.
[0018] In a further aspect the present invention, relates to a
point-of-use, scrubber for treating an effluent waste stream
comprising a toxic and/or hazardous component, said waste stream
deriving from a by-pass line of a semiconductor process, said
scrubber comprising:
[0019] an up-flow canister comprising: [0020] a lower section
plenum space; [0021] an upper section plenum space; [0022] at least
one dry resin sorbent bed layer therebetween [0023] an inlet in gas
flow communication with the by-pass process line; and [0024] an
outlet, arranged such that the process effluent waste stream flows
in an upward direction to effectively reduce the concentration of
the toxic/and or hazardous component from the effluent waste
stream.
[0025] In a further aspect the present invention, relates to a
process for reducing the concentration of a toxic and/or hazardous
component in a diluent waste stream deriving from a by-pass line of
semiconductor process tool, said process comprising, contacting the
diluent gas stream with a dry resin sorbent material having an
affinity for the toxic and/or hazardous component, to effect the
removal of at least a portion of the toxic and/or hazardous
component by a chemisorbent or physisorbent reaction between the
sorbent material and the toxic gas component in the process diluent
waste stream to below TLV.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 shows a schematic representation of a typical
epitaxial deposition system according to one embodiment of the
present invention.
[0027] FIG. 2 shows a schematic representation of a by-pass
abatement system according to one embodiment of the present
invention.
[0028] FIG. 3 shows a schematic representation of a bypass
abatement system according to a further embodiment of the instant
invention.
[0029] FIG. 4 shows a schematic representation of a bypass
abatement system according to a further embodiment of the instant
invention.
[0030] FIG. 5 shows a schematic representation of a bypass
abatement system according to a further embodiment of the instant
invention.
[0031] FIG. 6 shows a schematic representation of a bypass
abatement system according to a further embodiment of the instant
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] The present invention provides a by-pass abatement system
and process for removing pollutants from a by-pass effluent gaseous
stream, which is preferably derived from a semiconductor process
tool.
[0033] The invention comprises a scrubber in a by-pass line of a
semiconductor process tool, where prior to such invention, a toxic
gas component having been diluted by a diluent gas had been
by-passed from the process tool for discharge to atmosphere,
house-exhaust or other disposition steps.
[0034] The scrubber accommodates the collection of toxic and/or
hazardous gas components in a diluent by-pass stream, typically
considered pollutants, by contacting the diluent gas stream with a
sorbent bed material, which may be fixed or fluidized and may work
by physical adsorption or irreversible chemisorption.
[0035] Preferably the sorbent bed comprises a dry resin sorbent
material arranged in a canister, such that by-pass effluent enters
a headspace (plenum space) above or below the bed prior to contact
with the sorbent material. In order to provide headspace below the
bed, a support may be inserted into the canister to support the
sorbent bed. Preferably effluent enters the canister at a
cross-sectional center at a bed inlet (the cross-section being
transverse to the flow direction of the gas stream being flowed
through the bed).
[0036] The canister having any shape or size useful for treating a
by-pass effluent stream comprising a toxic and/or hazardous
component, provides for flow of the by-pass effluent stream into
the canister and through the sorbent bed in either an upward or a
downward direction, in a vertically upstanding canister. In a
preferred embodiment, the canister is of an up-flow design having a
cylindrical or cubic geometry and a volume that is between 0.1 to
1000 liters. In a more preferred embodiment, the canister volume is
between 4 and 50 liters.
[0037] The cubic container may be adapted to minimize volumetric
space requirements in storage, transport and use. In one specific
embodiment, the abatement system includes a cubic up-flow canister
having at least upper and lower plenum spaces and a sorbent bed
section therebetween.
[0038] As used herein the terms "cube and "cubic" are
interchangeable and are defined as having three dimensions and six
faces, where the angle between any two adjacent faces is a right
angle.
[0039] The up-flow canister as used herein is more fully described
in co-pending, commonly assigned, U.S. patent application Ser. No.
10/370,159 having a filing date of Feb. 19, 2003, for Low Pressure
prop Canister for Fixed Bed Scrubber Applications and Method of
Using Same, in the names of Paul J. Marganski, Theodore A. Shreve,
Joseph Sweeney, Jose Arno, Mark Holst, and Karl Olander, and is
incorporated herein by reference in its entirety.
[0040] The up-flow canister design counteracts any flow
distribution problems that otherwise may occur in the flow of gas
through the sorbent bed. Preferably, the up-flow canister
comprises:
[0041] a lower section plenum space;
[0042] a center section space, for containment of a sorbent bed
material;
[0043] an upper section plenum space;
[0044] an inlet in gas flow communication with the semiconductor
process effluent stream, comprising means for introducing the
process effluent stream to the lower section plenum space; and
[0045] an outlet comprising means for egress of the process
effluent stream from the canister.
[0046] The lower section plenum space, upper section plenum space
and sorbent bed section, may each occupy any percent of the
interior section of the canister and may be readily determined by
one skilled in the art. Variables affecting the volume occupied by
each of the three sections include but are not limited to process,
volumes of toxic component to be abated, resin choice, effluent
fluid flow, canister shape, inlet design etc.
[0047] As used herein, the by-pass abatement system and process are
intended to be broadly construed, and may alternatively comprise,
consist, or consist essentially of the specific stated components
hereafter specifically identified. Although exemplary embodiments
describe particular aspects, any changes, modifications, and
substitutions may be made without departing from the spirit and
scope of these embodiments.
[0048] In some prior art systems, diluent mass flow controller
vented to the POU water scrubber, during deposition, which was
typically ineffective in trapping and abating the toxic hydride
component.
[0049] The canister of the abatement system may couple to a
semiconductor process tool in a by-pass line in upstream or
downstream relationship to a house or other POU scrubber system or
the canister may couple to the by-pass line as a stand-alone
abatement system dedicated to the abatement of toxic and/or
hazardous component in the by-pass line. In a preferred embodiment,
the by-pass abatement system employing a dry resin sorbent bed in
an up-flow or down-flow canister, is either stand-alone or upstream
of a house or POU abatement system and serves to prevent the
release to atmosphere or house-exhaust, of toxic and/or hazardous
gaseous components in a process effluent stream, not trapped by the
primary abatement system.
[0050] Preferably, the by-pass abatement system targets a diluent
mass flow controller (MFC) in a process gas manifold, having
incorporated therein, a bypass line for exhaust of excess process
diluent gas from the process manifold. The by-pass line may be
coupled to a POU or house abatement system, atmosphere, vent or a
roof of a semiconductor facility.
[0051] When the excess process diluent gas contains toxic gas
components, and the by-pass line of the gas manifold exhausts the
excess process diluent to atmosphere, vent or a roof of a
semiconductor facility, the potential is present, for the toxic gas
component to enter the environment or depending on environmental
conditions, for the exhausted process gases to become entrained in
the air up-take system.
[0052] Furthermore, when the excess process diluent stream contains
a toxic gas component such as arsine, phosphine, germane, etc., a
point-of-use or house abatement system does not sufficiently
control the release of the toxic component to atmosphere, a vent or
a roof of a semiconductor facility.
[0053] In typical EPI process tools, a mixing manifold upstream of
the tool is used to combine diluent and doping gas, for example
hydrogen and arsine respectively. Dopant gas typically flows to the
mixing manifold through a first mass flow controller at rates of
between 0-300 sccm and diluent typically flows through a second and
separate mass flow controller at rates between 0-30 SLM. Between 80
to 99% of the resulting diluent hydride stream is by-passed from
the system. Accordingly, in a preferred embodiment, the abatement
system of the instant invention targets a by-pass line in the
mixing manifold, upstream of the mixing manifold mass flow
controller of an EPI process tool.
[0054] In a further embodiment, the abatement apparatus of the
present invention, comprises an up-flow canister, housing a sorbent
bed material comprising at least one metal oxide and more
preferably a mixture of at least two metal oxides.
[0055] Advantageously, the instant invention provides an
inexpensive solution to the release of unabated toxic gas component
from an EPI process, by targeting the diluent flow rather than the
total exhaust gas flow. The inexpensive benefits of the by-pass
abatement system include but are not limited to its zero foot-print
requirements and low maintenance requirements, as the system, may
be mounted above a process tool in exhaust duct work, has no moving
parts and generates only small amounts of toxic waste for disposal.
Additionally, there are no adverse conditions occurring in the EPI
process due to the operation of such a system.
[0056] The incorporation of an abatement system, using a dry resin
sorbent bed, having an affinity for toxic gas components such as
arsine, phosphine, germane, etc., into the by-pass line of a
process manifold, controls the release of the toxic gas components
to atmosphere, vent or the roof of a semiconductor facility.
Advantageously, the instant invention controls the exhaustion of
toxic and/or hazardous gaseous components, originating from a
by-pass line of a diluent gas manifold of a semiconductor
process.
[0057] FIG. 1 shows a typical Prior Art epitaxial deposition system
and process 100, comprising dopant gas source 102 and diluent gas
source 104 coupled to process line 106 through mixing manifold 108.
A dopant hydride gas component such as PH.sub.3, AsH.sub.3,
GeH.sub.4, etc. and diluent gas such as hydrogen, flow to mixing
manifold 108, in a predetermined ratio, through source delivery
line 110 and diluent delivery line 112, where the dopant and
diluent gases mix to form a diluent process effluent. Mass flow
controller 114, downstream of mixing manifold 108, controls the
flow of diluent process effluent to epitaxial deposition chamber
116. When, pressure controller 118, in the mixing manifold, exceeds
a predetermined pressure, excess diluent process effluent flows
into bypass line 120, through vent valve 126, to either atmosphere
124, or a point-of-use wet scrubber system or other house abatement
system 122 and then to atmosphere 124. Effluent waste stream from
epitaxial deposition chamber 116 flows through line 132 to
point-of-use wet scrubber unit 122 useful for abating process acid
gases such as HCl, SiH.sub.2Cl.sub.2 and SiHCl.sub.3, originating
from source 128. When process conditions include toxic and/or
hazardous hydride gases originating from manifold 108, the toxic
hydride gas component enters the atmosphere unabated, from both
deposition chamber 116 and bypass line 120 by way of vents 124 and
138 respectively.
[0058] FIGS. 2-5 show the epitaxial deposition system of FIG. 1,
having installed therein a by-pass scrubber according to further
embodiments of the present invention. In describing such
embodiments, with respect to FIGS. 2-5, like numerals will be used
in accordance with FIG. 1 to identify similar features.
[0059] FIG. 2 depicts an epitaxial deposition system employing a
point-of-use by-pass scrubber 134 coupled to bypass line 120. In
such a system, mass flow controller 114, downstream of mixing
manifold 108, controls the flow of diluent process effluent to
epitaxial deposition chamber 116. When, pressure controller 118, in
the mixing manifold, exceeds a predetermined pressure, excess
diluent process effluent comprising a toxic gas component, flows
into bypass line 120, through vent valve 126, to by-pass, up-flow
canister 134, where a sorbent bed material, housed therein,
contacts a toxic gas component, and a chemisorbent or physisorbent
reaction between the sorbent bed material and the toxic gas
component effectively reduces the concentration of the toxic gas
component in the process diluent stream to below TLV. Accordingly,
an effluent waste stream having a reduced concentration of toxic
gas component is exhausted from scrubber 134, to environment, or
for further disposition in exhaust line 124.
[0060] FIG. 3 depicts a system where excess diluent process
effluent comprising toxic gas component, flows into bypass line
120, through vent valve 126, to by-pass, up-flow canister 134,
where a sorbent bed material, housed therein, contacts the toxic
gas component and reacts to chemisorb or physisorb thereon at least
a portion of the toxic gas component originating from the diluent
mass flow controller 114. A resulting effluent stream having a
reduced concentration of at least one toxic gas component exits
canister 134 and flows through valve 142 to point-of-use abatement
system (for example wet scrubber) 122, for further treatment and
disposition 138.
[0061] FIG. 4 depicts a system where process fluid comprising a
toxic gas component is exhausted from epitaxial deposition reactor
116, into process exhaust line 132 to point-of-use scrubber system
122, where a wet or thermal reaction effects the removal of at
least a portion of the toxic gas component. The resulting effluent
waste stream is exhausted from system 122 in effluent waste stream
line 138 through valve 126 and into up-flow canister 134 where a
chemisorbent or physisorbent reaction between a sorbent bed housed
therein, and the toxic gas component in the effluent waste stream
effectively reduces the concentration of at least one toxic
component unabated by the main scrubber system 122. Accordingly,
such a system provides for a polisher for scrubbing an effluent
waste stream after a main or house abatement system has failed to
remove at least a portion of toxic gas component from the effluent
waste stream, said polisher comprising an up-flow canister having
disposed therein a dry resin sorbent bed.
[0062] FIG. 5 depicts a system similar to that described
hereinabove for FIG. 2, except for further inclusion of epi-reactor
by-pass line 144, which provides for an alternative scrubber system
for effluent waste stream deriving from reactor 116. Such a system
provides for switchover from a main abatement system 122 to a
by-pass scrubber system 134, by way of valves 142 and 126. Such a
system enables switchover from a main scrubber 122, to a by-pass
system 134, for more efficient effluent treatment as well as a back
up in the event the main abatement system is taken off-line.
[0063] The dry-resin sorbent, abatement system of the instant
invention, is useful for removing up to 99% of diluted hydride gas
component in a bypass line of an epitaxial deposition process tool,
and when the dry resin sorbent system is placed downstream of a
point-of-use wet scrubber, which serves as a main abatement system
for a particular semiconductor process tool, the instant invention,
aids in the removal of toxic gas component unabated by the wet
abatement system. Thus the instant invention obviates the potential
release of hazardous and toxic gas components to a ventilation
system and/or to the environment.
[0064] In a further embodiment, the present invention is directed
to a process for reducing the concentration of at least one toxic
and/or hazardous component in an effluent waste stream deriving
from a by-pass line of a semiconductor process tool, comprising
contacting the toxic and/or hazardous component with a dry resin
sorbent material that is reactive with the toxic and/or hazardous
component to substantially reduce the concentration of the toxic
and/or hazardous component in the effluent stream. Preferably the
toxic and or hazardous component is a hydride gas and the hydride
gas component reacts with the dry resin sorbent material by
chemisorption and/or physisorption to reduce the concentration in
the effluent stream, of the hydride gas component.
[0065] By targeting the diluent mass flow controller, EPI process
gases, such as, SiH.sub.2Cl.sub.2 and SiHCl.sub.3, which are
effectively controlled using wet and thermal oxidation systems pass
to a thermal, wet or other point-of-use abatement system for
treatment, while the diluent process line comprising from 80-99% of
diluted hydride dopant gases for discharge from the system upstream
of the process tool, has coupled thereto, an abatement system,
comprising a dry resin sorbent bed, for controlling the release of
toxic and hazardous hydride gases in a bypass line that are sent to
a point-of-use or house scrubber system comprising a wet abatement
system having little to no affect at scrubbing hydride dopant
gases.
[0066] FIG. 6 shows a bypass abatement system 200, according to one
embodiment of the present invention. Diluent process effluent
stream comprising a toxic gas component, originating from mixing
manifold 210, upstream from mass flow controller 202 and process
tool 230, flows in bypass line 204, through valve 206, and inlet
210, into lower section plenum space 212 of canister 214, where the
effluent stream mixes and expands, until the process effluent is
mass transported into a first sorbent bed section 216, in an
up-flow direction, by a pressure differential induced by fluid
motive force device, such as an eductor or venturi 218. The toxic
gas component contacts sorbent material 216, and the sorbent
material, having an affinity for the toxic gas component retains
thereon and/or reacts therewith, by chemisorption or physisorption
at least a portion of the toxic gas component, in an evenly
distributed manner, thereby creating a uniform fluid front or mass
transfer zone (MTZ), which theoretically transfers evenly through
the sorbent bed material.
[0067] The effluent stream having a reduced concentration of toxic
gas component exits the sorbent bed section 216 and flows into an
optional second plenum space 228, where the effluent stream, again
mixes and expands, until the process effluent is mass transported
into an optional second sorbent bed section 232, in an up-flow
direction, by the pressure differential induced by the fluid motive
force device 218. Toxic gas component not chemisorbed or
physisorbed by first sorbent bed section 216, contacts sorbent bed
section 232 and second sorbent bed section 232, retains thereon
and/or reacts therewith, by chemisorption or physisorption, at
least a second portion of toxic gas component, in an evenly
distributed manner.
[0068] The effluent stream having a reduced concentration of toxic
gas component, exits second sorbent bed section where it again
mixes and expands until exhaustion through outlet port 222 where
the effluent stream passes to environment, further treatment or
other disposition steps.
[0069] Canister 214 may employ gas flow distributor elements (not
shown) to effect a central efflux of gas for distribution across
the entire cross-section of the container, to provide uniform flow
without occurrence of hydrodynamic anomalies, such as dead space,
bypassing, etc.
[0070] Various ancillaries are usefully employed with the scrubber
system as described hereinabove including but not limited to end
point monitoring, pressure and temperature sensing. Such
ancillaries be linked in signal transmission relationship with a
computer or other automatic process control means, for enabling
automation responsiveness to various system parameters.
[0071] Referring again to FIG. 6, an end point monitor 224, such as
a toxic gas sensor, may be coupled to an output module for
outputting an indication of breakthrough of the contaminant(s) in
the effluent gas stream when the capacity of the scrubber bed for
active processing of the effluent gas stream is exhausted or
reaches a predetermined approach to exhaustion (e.g., reaches a
point of exhaustion of 95% of the total capacity of the dry
scrubber material).
[0072] Optionally, a pressure sensing device 234 and/or 220, to
monitor the pressure at the canister inlet and/or outlet
respectively, may be coupled to an output module for outputting an
indication of pressure for increasing or decreasing the energy
input on the downstream fluid motive force device or to signal a
blockage in the sorbent bed or scrubber inlet.
[0073] A thermal monitoring device 226, may be coupled to an output
module for outputting an indication of temperature within the
canister and sorbent bed(s). In this respect, a number of thermal
monitoring devices, e.g., thermocouples, temperature probes,
pyroelectric devices, etc., may be employed along the length of the
bed in the direction of gas flow therethrough.
[0074] Advantageously, the instant invention provides an
inexpensive solution to the potential release of toxic hydride
gases to a semiconductor facility and/or environment. The
inexpensive benefits of the system are in part due to the small
footprint of the system and in further part due to the low
maintenance required for such a system as there are no moving parts
and only small amounts of toxic waste are generated for disposal.
Additionally, there are no adverse conditions occurring at the CVD
process due to the operation of such a system.
[0075] In a specific illustrative embodiment, a dry scrubber
container may be employed, utilizing an up-flow design and
operation, with centered up-flow of gas at the bed inlet.
Additionally, a heat exchange coil in the bed arranged for
maintaining bed temperature at a desired temperature level.
[0076] The sorbent material used in the up-flow canister of the
present invention may react with contaminants in an effluent stream
(adsorbate) by physical or chemical adsorption kinetics. Physical
adsorption is due to intermolecular forces between an adsorbent and
adsorbate (e.g. van der Waals interactions) and thus is reversible.
Chemical adsorption involves a chemical reaction between the
adsorbent and the adsorbate. Preferably the up-flow canister of the
present invention utilizes a dry scrubbing medium having a
chemisorption relationship with process contaminants. Various
options are usefully employed with the scrubber system as described
hereinabove including but not limited to end point monitoring,
pressure and temperature sensing.
[0077] The system of the instant invention, preferably utilizes a
dry resin sorbent material for trapping by chemisorption or
physisorption reaction toxic gas components in a by-pass diluent
waste stream. The dry resin sorbent material may comprise any
combination of resins useful for scrubbing process gases specific
to the particular process tool requiring effluent abatement and may
be readily determined by those of skill in the art. Sorbent bed
materials include but are not limited to: carbon, CuSO.sub.4,
Cu(OH.sub.2), CuO, CuCO.sub.3, CuCO.sub.3.Cu(OH).sub.2, CU.sub.2O,
MnO.sub.x, wherein x is from 1 to 2 inclusive, AgO, Ag.sub.2O, CoO,
CO.sub.3O.sub.4, Cr.sub.2O.sub.3, CrO.sub.3, MoO.sub.2, MoO.sub.3,
TiO.sub.2, NiO, LiOH, Ca(OH).sub.2, CaO, NaOH, KOH,
Fe.sub.2O.sub.3, ZnO, Al.sub.2O.sub.3, K.sub.2CO.sub.3, KHCO.sub.3,
Na.sub.2CO.sub.3, NaHCO.sub.3, NH.sub.3OH, Sr(OH).sub.2, HCOONa,
BaOH, KMnO.sub.4, SiO.sub.2, ZnO, MgO, Mg(OH).sub.2,
Na.sub.2O.sub.3S.sub.2, SiO.sub.2, triethylenediamine (TEDA) and
mixtures thereof. Preferably, the dry resin sorbent material of the
instant invention comprises at least one of CuSO.sub.4,
Cu(OH.sub.2), CuO, CuCO.sub.3, CuCO.sub.3.Cu(OH).sub.2, Cu.sub.2O,
MnO.sub.x, wherein x is from 1 to 2 inclusive, Ca(OH).sub.2, and
CaO.
[0078] Additionally, the sorbent material may further comprise a
stabilizer or the active component may be impregnated into or
coated onto an adsorbent substrate. Stabilizing materials help in
the manufacturing of the sorbent media (e.g. in extrusion), and in
some situations serves to prevent the sorbent media from
decomposing. Useful stabilizers include but are not limited to the
elements Be, Mg, transition metals selected from V, Mo, Co, Ni, Cu,
Zn, B, Al, Si, Pb, Sb, Bi and oxides, hydroxides hydrogen
carbonates, hydrogen sulfates, hydrogen phosphates, sulfides,
peroxides, halides, carboxylates, and oxy acids thereof.
[0079] The instant invention as it relates to a by-pass abatement
system and associated process for removing toxic and/or hazardous
hydride gas components from a process effluent waste stream
deriving from a by-pass line of a mixing manifold of an Epitaxial
deposition process tool, in one embodiment comprises an up-flow or
down-flow canister housing therein a dry resin sorbent bed material
comprising a metal oxide. The metal oxide sorbent material having
an affinity for metal hydrides reacts therewith to substantially
remove the hydride species from the effluent waste stream, until
the capacity of the dry scrubber material for hydride species is at
least partially exhausted.
[0080] To at least partially regain the capacity of the dry resin
sorbent material for the hydride species, the instant invention may
further comprise means to contact the at least partially exhausted
capacity dry resin sorbent material with an oxidant effective to
regenerate the dry scrubber material subsequent to diminution of
hydride removal capacity thereof, as more fully described in U.S.
patent application Ser. No. 09/717,439, filed Nov. 21, 2000, now
issued as U.S. Pat. No. 6,491,884 the disclosure of which, is
hereby incorporated herein in its entirety. The oxidant may be
joined in oxidant supply relationship to the bed of dry resin
sorbent material such that flow circuitry is arranged to flow
oxidant in contact with the bed of sorbent material. Preferably,
the flow circuitry is arranged to repetitively and alternatingly
flow a diluent gas hydride-containing waste effluent stream
followed by oxidation regeneration of the sorbent bed material.
[0081] Accordingly, while the invention has been described herein
with reference to specific features and illustrative embodiments,
it will be recognized that the utility of the invention is not thus
limited, but rather extends to and encompasses other features,
modifications and alternative embodiments as will readily suggest
themselves to those of ordinary skill in the art based on the
disclosure and illustrative teachings herein. The claims that
follow are therefore to be construed and interpreted as including
all such features, modifications and alternative embodiments within
their spirit and scope.
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