U.S. patent application number 11/244744 was filed with the patent office on 2007-04-12 for pump apparatus for semiconductor processing.
This patent application is currently assigned to The BOC Group, Inc.. Invention is credited to Graeme Huntley.
Application Number | 20070081893 11/244744 |
Document ID | / |
Family ID | 37911212 |
Filed Date | 2007-04-12 |
United States Patent
Application |
20070081893 |
Kind Code |
A1 |
Huntley; Graeme |
April 12, 2007 |
Pump apparatus for semiconductor processing
Abstract
The invention relates to a pump apparatus for use in
semiconductor processing. The apparatus may include a single pump
configured to transition a substance flow from about molecular
pressure to about atmospheric pressure.
Inventors: |
Huntley; Graeme; (Wembdon,
GB) |
Correspondence
Address: |
Ira Lee Zebrak;The BOC Group, Inc.
Legal Services-IP
575 Mountain Ave.
Murray Hill
NJ
07974
US
|
Assignee: |
The BOC Group, Inc.
|
Family ID: |
37911212 |
Appl. No.: |
11/244744 |
Filed: |
October 6, 2005 |
Current U.S.
Class: |
415/229 |
Current CPC
Class: |
F04D 17/168 20130101;
F04D 23/008 20130101; F04D 19/046 20130101; F04D 19/042
20130101 |
Class at
Publication: |
415/229 |
International
Class: |
F04D 29/04 20060101
F04D029/04 |
Claims
1. An apparatus for use in semiconductor processing, comprising: a
single pump configured to transition a substance flow having an
input pressure less than or equal to about 10.sup.-1 millibar to an
output pressure greater than or equal to about 100 millibar.
2. The apparatus of claim 1, wherein the single pump is configured
to transition a substance flow having an input pressure less than
or equal to about 10.sup.-3 millibar to an output pressure greater
than or equal to about 100 millibar.
3. The apparatus of claim 1, wherein the single pump is configured
to transition the substance flow to an output pressure greater than
or equal to about 1 bar.
4. The apparatus of claim 1, wherein the single pump includes no
more than a single rotatable shaft.
5. The apparatus of claim 4, wherein the single shaft consists
essentially of a single vertical axis.
6. The apparatus of claim 4, wherein the single shaft is
continuous.
7. The apparatus of claim 1, further comprising a semiconductor
processing tool associated with the single pump.
8. The apparatus of claim 1, wherein a flow rate of the substance
flow ranges from about 1,000 liters per second to about 10,000
liters per second.
9. The apparatus of claim 8, wherein the flow rate of the substance
flow ranges from about 1,600 liters per second to about 3,000
liters per second.
10. The apparatus of claim 1, wherein the single pump includes at
least one ball bearing.
11. The apparatus of claim 10, wherein at least one ball bearing is
associated with a portion of the single pump that exhausts
substance flow having an output pressure greater than or equal to
about 100 millibar.
12. The apparatus of claim 1, wherein the single pump includes at
least one magnetic bearing.
13. The apparatus of claim 12, wherein the at least one magnetic
bearing is associated with a portion of the single pump that
receives substance flow having an input pressure less than or equal
to about 10.sup.-2 millibar.
14. The apparatus of claim 1, wherein the single pump includes no
more than one motor.
15. The apparatus of claim 1, wherein the single pump includes no
more than one bearing suspension unit.
16. The apparatus of claim 10, wherein the single pump includes at
least one magnetic bearing.
17. The apparatus of claim 16, wherein the at least one ball
bearing is associated with a portion of the single pump that
exhausts the substance flow having an output pressure greater than
or equal to about 100 millibar.
18. The apparatus of claim 16, wherein the at least one magnetic
bearing is associated with a portion of the single pump that
receives substance flow having an input pressure less than or equal
to about 10.sup.-2 millibar.
19. An apparatus for use in semiconductor processing, comprising: a
single pump configured to transition a substance flow from about
molecular pressure to about atmospheric pressure.
20. An apparatus for use in semiconductor processing, comprising: a
single pump configured to transition a substance from
turbomolecular flow to atmospheric flow.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a pump apparatus for use in
semiconductor processing. The apparatus may include a single pump
configured to transition a substance flow from about molecular
pressure to about atmospheric pressure.
BACKGROUND OF THE INVENTION
[0002] Semiconductor wafers are used to form a number of different
types of devices. For example, wafers, or portions of wafers, may
be used to form memory devices, microprocessor unit devices, or
combinations of the two devices. The devices may be very small,
(e.g., on the order of only one micron), and thus these devices are
often manufactured in large batches. In some instances, a single
wafer may have hundreds of devices manufactured on it.
[0003] In order to manufacture a device on a wafer, a number of
discrete steps are performed. Although the number of steps may vary
greatly depending on the type and complexity of the device, a
typical manufacturing process may include anywhere between 100 and
300 individual steps between the initial step of providing an
initial substrate and the finals step of extracting individual
devices from the wafer and installing them in personal computers,
telephones, mobile phones, or other electronic equipment.
[0004] Some of the steps in semiconductor wafer processing may
include etching away selected material, depositing selected
materials, and performing selective ion implantation in the silicon
wafer. Many of these steps are performed by tools especially
designed for the particular step, but several steps may also be
performed by a single tool. Because these steps may be performed in
a variety of locations, the wafer may often be moved. For example,
the wafer may be placed in and taken out of ion implanter tools,
transported by cassettes, placed in and taken out of deposition
tools, and placed in and taken out of etch tools, etc.
[0005] As mentioned above, etching is one form of processing that
may be performed on a wafer. The wafer may be etched a number of
different times at a number of different levels for a number of
different reasons. For example, one type of etching step includes
placing a photoresist type material over an area of the wafer. The
photoresist on the wafer may be then be exposed to a light source
with a specific wavelength and a specific pattern. The exposure of
the photoresist to the light source may alter the chemical
composition of the exposed area such that the photoresist either
"hardens" so that when a chemical is applied, the
"hardened"photoresist remains, or "softens" so that when a chemical
is applied, the "softened"photoresist is removed. In either case, a
desired photoresist pattern remains on the wafer. Using this
remaining photoresist as a mask, chemical substances may be applied
to the wafer so as to etch away or remove exposed portions of the
wafer. Thus, a desired pattern may be "etched" into the silicon
wafer.
[0006] The devices and/or patterns that are etched into the wafer
often have dimensions that are on the order of one micron. Because
the dimensions being dealt with are so small, etching processes are
especially susceptible to contaminants. For example, foreign
molecules may become lodged in the channels etched into the wafers,
and the existence of such flaws may prevent a device or portions of
the device from working properly. Accordingly, in order to minimize
these flaws, much attention is paid to the method by which the
etching is performed, specifically by working to minimize the
number of contaminants in the system.
[0007] The most common method of controlling the etching is by
etching in a vacuum chamber using a plasma. The vacuum chamber is,
by definition, kept at a low pressure (e.g., molecular pressure),
for example, between pressures of about 10.sup.-3 millibar and
about 10.sup.-1 millibar. The plasma used to etch the wafers may
include the addition of any number of substances, such as
fluorocarbons or perflourocarbons, which within the plasma may be
broken up into smaller portions, such as fluorine and fluorine
radicals. These smaller portions react with the exposed portions of
the wafer and "etch away" that portion of the wafer through the
formation of volatile reactant by-products. Other substances may be
used depending on the substrate to be etched. Performing this
procedure under vacuum substantially prevents contaminants from
entering the system (as the chemicals present are normally only
those specifically introduced into the system) and moderates the
reaction rate as the molecular density is lower.
[0008] In a number of current etching procedures, a large amount of
reactants are conveyed past the wafer at high speeds, for example,
on the order of thousands of liters per second. This runs contrary
to the desire to minimize the number of contaminants by keeping the
pressure in the vacuum chamber low. What results is a desire to
pass etching substances through the vacuum chamber at high speeds,
but low pressures, and thus specialized pumps are often
desired.
[0009] Currently, there are two discrete, completely separate,
unintegrated pumps used in conjunction with each other to provide a
high flow rate of etching substances at low pressures. The pumps
have, among things, separate housings, separate controllers,
separate electrical connections, and separate fluid connections,
and are located long distances away from one another in different
rooms of a wafer processing facility.
[0010] In some current configurations, an inlet of a first pump is
bolted to the bottom of the vacuum chamber and receives the
substances from the vacuum chamber that are flowing at the low
pressures. The first pump then gradually increases the pressure of
the substance flow from the molecular level (at the inlet) to about
the transition level (at the outlet). The substance flow is then
sent through a tube or pipe to a second pump. The second pump is
typically located in another room of the wafer processing facility
(e.g., a basement) for several reasons, most prominent of which are
its size, the amount of noise it generates, and its maintenance.
The flow path (e.g., tube) connecting the pumps is typically
between 5 and 15 meters in length, with a minimum length of 3
meters and a maximum length of 20 meters. The second pump gradually
increases the pressure of the substance flow from about the
transition level (at the inlet) to about atmospheric pressure (at
the outlet). The second pump then exhausts the substance flow.
[0011] There are some drawbacks associated with the current dual
pump arrangement. For example, having the second pump in a room
separate from the first pump is often an inefficient use of space.
In addition, there are efficiency losses associated with flowing
the substances through a long tube connecting the pumps.
Accordingly, alternative arrangements and/or configurations of
multiple pumps are desired.
SUMMARY OF THE INVENTION
[0012] In the following description, certain aspects and
embodiments of the invention will become evident. It should be
understood that the invention, in its broadest sense, could be
practiced without having one or more features of these aspects and
embodiments. It should also be understood that these aspects and
embodiments are merely exemplary.
[0013] One aspect, as embodied and broadly described herein, may
relate to an apparatus for use in semiconductor processing.
[0014] An exemplary embodiment of the invention may include an
apparatus for use in semiconductor processing. The apparatus may
include a single pump configured to transition a substance flow
having an input pressure less than or equal to about 10.sup.-1
millibar to an output pressure greater than or equal to about 100
millibar.
[0015] Various embodiments of the invention may include one or more
of the following aspects: the single pump may be configured to
transition a substance flow having an input pressure less than or
equal to about 10.sup.-3 millibar to an output pressure greater
than or equal to about 100 millibar; the single pump may be
configured to transition the substance flow to an output pressure
greater than or equal to about 1 bar; the single pump may include
no more than a single rotatable shaft; the single shaft may consist
essentially of a single vertical axis; the single shaft may be
continuous; a semiconductor processing tool associated with the
single pump; a flow rate of the substance flow may range from about
1,000 liters per second to about 10,000 liters per second; the flow
rate of the substance flow may range from about 1,600 liters per
second to about 3,000 liters per second; the single pump may
include at least one ball bearing; at least one ball bearing may be
associated with a portion of the single pump that exhausts
substance flow having an output pressure greater than or equal to
about 100 millibar; the single pump may include at least one
magnetic bearing; the at least one magnetic bearing may be
associated with a portion of the single pump that receives
substance flow having an input pressure less than or equal to about
10.sup.-2 millibar; the single pump may include no more than one
motor; the single pump may include no more than one bearing
suspension unit; the single pump may include at least one magnetic
bearing; the at least one ball bearing may be associated with a
portion of the single pump that exhausts the substance flow having
an output pressure greater than or equal to about 100 millibar; and
the at least one magnetic bearing may be associated with a portion
of the single pump that receives substance flow having an input
pressure less than or equal to about 10.sup.-2 millibar.
[0016] Another exemplary embodiment of the invention may include an
apparatus for use in semiconductor processing. The apparatus may
include a single pump configured to transition a substance flow
from about molecular pressure to about atmospheric pressure.
[0017] A further exemplary embodiment of the invention may include
an apparatus for use in semiconductor processing. The apparatus may
include a single pump configured to transition a substance from
turbomolecular flow to atmospheric flow.
[0018] Aside from the structural relationships discussed above, the
invention could include a number of other forms such as those
described hereafter. It is to be understood that both the foregoing
description and the following description are exemplary only.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The accompanying drawings, which are incorporated in and
constitute a part of this specification. The drawings illustrate
several embodiments of the invention and, together with the
description, serve to explain some principles of the invention. In
the drawings:
[0020] FIG. 1A is a schematic view of an embodiment of an apparatus
in accordance with the present invention;
[0021] FIG. 1B is a schematic view of another embodiment of the
apparatus;
[0022] FIG. 2 is a schematic view of a portion of the apparatus of
FIG. 1B;
[0023] FIG. 3 is a schematic view of a portion of the apparatus of
FIG. 1A;
[0024] FIG. 4 is a schematic view of a portion of the apparatus of
FIG. 1A;
[0025] FIG. 5 is a schematic view of a further embodiment of the
apparatus disposed in a single room of a semiconductor processing
facility;
[0026] FIG. 6 is a schematic view of still another embodiment of
the apparatus associated with a semiconductor processing tool;
[0027] FIG. 7 is a schematic view of a portion of a still further
embodiment of the apparatus;
[0028] FIGS. 8A and 8B are perspective views of portions of yet
another embodiment of the apparatus;
[0029] FIGS. 8C and 8D are schematic views of the portions of FIGS.
8A and 8B; and
[0030] FIG. 9 is a schematic view of a yet further embodiment of
the apparatus.
DESCRIPTION OF THE EMBODIMENTS
[0031] Reference will now be made in detail to some possible
embodiments of the invention, examples of which are illustrated in
the accompanying drawings. Wherever possible, the same reference
numbers are used in the drawings and the description to refer to
the same or like parts.
[0032] FIGS. 1-9 depict exemplary embodiments of an apparatus for
use in semiconductor processing. The apparatus may include a pump 1
having one or more of each of a turbomolecular stage 100, a drag
stage 200, and a dry stage 300. For example, pump 1 may include all
three of turbomolecular stage 100, drag stage 200, and dry stage
300. In another example, pump 1 may include only one of
turbomolecular stage 100, drag stage 200, and dry stage 300. In a
further example, as shown in FIG. 9, pump 1 may include a
turbomolecular stage 100, a plurality of drag stages 200, and a dry
stage 300. In some examples, pump 1 may be configured to receive a
substance flow at about molecular pressure, for example, having a
pressure of about 5.times.10.sup.-3 millibar, at a flow rate
ranging from about 1600 liters per second to about 2000 liters per
second, and exhaust the substance flow at about atmospheric
pressure.
[0033] Also or alternatively, pump 1 may be configured to
transition a substance flow having an input pressure less than or
equal to about 10.sup.-2 millibar (e.g., about 10.sup.-3 millibar)
to an output pressure greater than or equal to about 100 millibar
(e.g., about 1 bar ), and/or may be configured to accommodate a
flow rate of the substance flow that ranges from about 1,000 liters
per second (e.g., about 1,600 liters per second) to about 10,000
liters per second (e.g., about 3,000 liters per second).
[0034] Turbomolecular stage 100 may be a stage configured to
provide turbomolecular flow of a substance at about molecular
pressure such that molecules of the substance are more likely to
collide with at least one interior wall 101 (FIG. 4) of
turbomolecular stage 100 rather than into other substance
molecules. Turbomolecular stage 100 may have an inlet 102
configured to receive a flow of the substance at a first pressure
(e.g., from a semiconductor processing chamber) and an outlet 103
to expel the substance flow at a second pressure, for example, to
one or more of drag stage 200, dry stage 300, or the atmosphere. As
shown in FIG. 1, turbomolecular stage 100 may include blades 104
configured to rotate together to transition substance flow from an
input pressure of about 10.sup.-3 millibar to about 10.sup.-1
millibar, for example, when the input flow passing through inlet
102 is from an etching tool. Turbomolecular stage 100 may also or
alternatively include blades 104 configured to rotate together to
transition substance flow at lower input pressures, for example, a
pressure as low as about 10.sup.-8 millibar when the input flow
passing through inlet 102 is from a tool or other structure
associated with an application other than etching, for example,
physical vapor deposition ("PVD"). Turbomolecular stage 100 may be
configured to transition substance flow to a second pressure of
about 1 millibar to about 10 millibar. In some embodiments, the
second pressure may be about 100 millibar to about 1 bar.
[0035] Blades 104 may be disposed in turbomolecular stage 100 using
bearings. The bearings may be mechanical bearings, such as ball
bearings or a central shaft, or may be magnetic bearings configured
to magnetically levitate blades 104 within turbomolecular stage
100. In some embodiments, turbomolecular stage 100 may have
multiple types of bearings. For example, blades 104 closer to inlet
102 may be suspended by magnetic bearings (e.g., when the flow rate
of substance flow through the inlet ranges from about 2000 liters
per second to about 300 liters per second), while blades 104 closer
to outlet 103 may be suspended by mechanical bearings. Magnetic
bearings may be desirable at higher speeds of substance flow
because they may actively reduce vibrations.
[0036] In alternate examples shown in FIGS. 7 and 9, blades 104 may
be disposed on a shaft 106. A top portion of shaft 106 closer to
inlet 102 may be suspended by magnetic bearings, and a bottom
portion of shaft 106 closer to outlet 103 may be suspended by
mechanical bearings. In various embodiments, however, shaft 106 may
be suspended by any number of bearings of any type and in any
combination (e.g., two mechanical bearings or two magnetic
bearings).
[0037] Adjacent blades 104 may be spaced from one another by an
intervening stator 105. Stators 105 may remain substantially
stationary during a substance pumping process and may be fixed to
the inner wall 101 that surrounds the blades 104.
[0038] The molecules entering the turbomolecular stage 100 may have
a substantially random motion. These molecules may collide with a
rotating blade 104 and pick up the blade's 104 velocity such that
upon leaving each blade 104, the molecule has a velocity
substantially the same as that of blade 104 as well as having an
intrinsic thermal velocity substantially similar to that of the
blade 104. Thus, compression may be generated by a combination of
blades 104 providing a higher transmission probability downwards
rather than upwards due to the angle of blades 104 and the relative
blade velocity. Stationary stator 105 also may be configured such
that it generates compression through a combination of the relative
gas velocity and the stator 105 providing a higher transmission
probability downwards as compared to upwards due to the angle of
the stator blade. Upward and downwards may refer to movement of gas
relative to the outlet 103 (e.g., exhaust) of the pump. For
example, downwards may refer to movement of gas towards the exhaust
of the pump (e.g., moving toward a higher pressure area and/or
being compressed), while upwards may refer to movement of gas away
from the exhaust of the pump (e.g., moving toward a lower pressure
area and/or being expanded). Stator 105 may have a relative
velocity from the reference of the molecule such that equal pumping
may be provided by stator 105 and blade 104.
[0039] One or more of blades 104, intervening stators 105, and/or
other portions of the turbomolecular stage 100 may be configured to
efficiently move substances at low pressures. The turbomolecular
stage 100 may typically operate with inlet pressures ranging from
about 10.sup.-1 millibar to about 10.sup.-8 millibar (10.sup.-7
millibar) and corresponding outlet pressures from about 0.1
millibar to about 1 millibar or less, depending, for example, on
flow and the size of the pump downstream.
[0040] Additional details concerning exemplary configurations of a
turbomolecular stage 100 with blades 104 and stators 105, and its
various components, are set forth in U.S. Pat. Nos. 6,109,864 and
6,778,969, which are both incorporated herein by reference in their
entirety.
[0041] Pump 1 may include a drag stage 200, an example of which is
shown in FIG. 2. Drag stage 200 may have an inlet 204 configured to
receive a flow of the substance at a first pressure (e.g., from a
semiconductor processing chamber or an outlet 103 of turbomolecular
stage 100) and an outlet 205 to expel the substance flow at a
second pressure, for example, to one or more of turbomolecular
stage 100, dry stage 300, or the atmosphere. The second pressure
may depend on the pressure to which pump 1 may ultimately exhaust.
For example, in some embodiments, pump 1 may not exhaust to
atmospheric pressure, thus only turbomolecular stage 100 and drag
stage 200 may be used.
[0042] Drag stage 200 may include two or more co-axial hollow
cylinders 201, 202. Each of cylinders 201, 202 may be composed of
multiple cylindrical portions, for example, two or more cylindrical
portions adjacent to each other (e.g., one cylindrical portion may
be closer to inlet 204, while another cylindrical portion may be
closer to outlet 205, with both cylindrical portions having
substantially the same dimensions and/or configurations). Such
cylindrical portions may be desirable, for example, so as to
operate different parts of drag stage 200 at different efficiencies
depending on pressure.
[0043] One or more of the cylinders 201, 202 may have a helical
thread 203 provided on its surface facing the other cylinder 201,
202. For example, FIG. 2 schematically shows a thread 203 on an
inner surface of outer cylinder 201. In operation, one or more of
the cylinders 201, 202 may rotate at relatively high speeds, for
example, up to about twenty-thousand revolutions-per-minute or
more. At low pressures, molecules may strike the surface of the
rotating helical thread 203, giving the molecules a velocity
component and tending to cause the molecules to have the same
direction of motion as the surface against which they strike. The
molecules may be urged through drag stage 200 in this manner and
exit drag stage 200 at a higher pressure than that at which they
entered. Helical thread 203 may have a relatively close clearance
with cylinder 202, for example, between about 0.1 mm and about 0.5
mm depending on the pressure. Such a close clearance may provide a
greater probability of molecules moving towards the outlet of the
pump than towards the inlet.
[0044] Drag stage 200 may typically operate with inlet pressures
ranging from about 10.sup.-1 millibar to about 10.sup.-7 millibar
(e.g., about 10.sup.-6 millibar) and corresponding outlet pressures
of from about 10 millibar to about 1 millibar or less, for example,
depending on flow and the size of the pump downstream. At least
some of the cylinders 201, 202, helical thread 203, and/or other
parts of the drag stage 200 (e.g., those disposed closer to outlet
205) may be configured to efficiently move substances at higher
pressure. Further details regarding exemplary drag stages and their
various components can be found in U.S. Pat. No. 5,772,395, which
is incorporated herein by reference in its entirety.
[0045] Drag stage 200 may have an alternate configuration, for
example, as shown in FIG. 9. Drag stage 200 may have several
stationary cylinders 201 having a helical thread 203 and several
rotating cylinders 202. Rotating cylinders 202 may be connected,
may rotate at substantially the same rotational speed, and/or may
be disposed on the same shaft 106 as blades 104. Each stationary
cylinder 201 and surface of rotating cylinder 202 facing its
respective stationary cylinder may comprise a separate drag stage
200. Some drag stages 200 may include a surface of a stationary
cylinder 201 having a helical thread 203 facing radially outward
and also facing a substantially flat radially inward surface of a
rotating cylinder 202. Some drag stages 200 may have the opposite
configuration. Each stationary cylinder 201 may have helical
threads 203 on its radially outward surface and/or its radially
inward surface. Each rotating cylinder 202 may face a surface of a
stationary cylinder 201 having helical threads 203 on its radially
outward surface and/or its radially inward surface.
[0046] Each drag stage 200 may be in flow communication with other
drag stages 200. Each drag stage 200 may be disposed radially
inward or outward from other drag stages 200. Each drag stage 200
may have a different configuration. For example, the helical
threads 203 in each drag stage 200 may have a different length than
helical threads 203 in other drag stages 200. Drag stages 200 may
be disposed radially outward from turbomolecular stage 100. Each
drag stage 200 may be configured to increase a pressure of the
substance while the substance flows through the drag stage 200, and
then exhaust the substance to a more radially outer drag stage 200
until the substance is exhausted by the final drag stage 200 to the
dry stage 300, for example, at about atmospheric pressure or
atmospheric flow.
[0047] Pump 1 may include a dry stage 300 as show in FIG. 3. Dry
stage 300 may be a pump configured to provide transition flow
and/or viscous flow of the substance such that molecules of the
substance are more likely to collide with each other rather than at
least one interior wall 305 of the pump. Dry stage 300 may have an
inlet 301 that receives a substance flow at a first pressure (e.g.,
from an outlet of turbomolecular stage 100 or drag stage 200) and
an outlet 302 that expels the substance flow at a second pressure
(e.g., about atmospheric pressure). One exemplary type of dry pump
300, an example of which is shown in FIG. 3, may include rotating
blades 303, typically having a different geometry than those of a
turbomolecular pump, such that they are suitable for operating at
higher pressures with intervening stators 304. The blades 303 and
stators 304 may be configured to transition substance flow from an
input pressure of about 1 millibar to about 10 millibar or less
(e.g., a pressure as low as about 0.1 millibar) to about 100
millibar to about 1 bar (e.g., atmospheric pressure). Blades 303
may be disposed in dry stage 300 using bearings (e.g., one or more
of a ball bearing, a cylinder shaft, and a magnetic bearing).
Stators 304 may be fixed to a cylindrical housing that surrounds
the blades 303. Blades 303 and stators 304 may operate
substantially similar to the blades 103 and stators 104 described
above with respect to turbomolecular stage 100, in that dry stage
300 may cause an increase in the pressure of the substance passing
into dry stage 300 via the inlet 301 before the substance exits dry
stage 300 via outlet 302. Examples of dry stages and their various
components are disclosed in U.S. Pat. Nos. 6,244,841, 6,705,830,
6,709,226, 6,755,611 B1, which are all incorporated herein by
reference in their entirety. Other suitable examples of dry stages
are disclosed in U.S. Pat. Nos. 6,129,534, 6,200,116, 6,379,135,
and 6,672,855, which are incorporated herein by reference in their
entirety.
[0048] Dry stage 300 may have an alternate configuration, for
example, as shown in FIGS. 8A, 8B, 8C, 8D, and 9. In the alternate
configuration, dry stage 300 may include a regenerative rotor 350
and a regenerative stator 370.
[0049] As shown in FIGS. 8A, regenerative rotor 350 may include a
plurality of substantially circular protrusions 351 extending from
a surface of regenerative rotor 350. Protrusions 351 may have a
plurality of blades 352 extending therefrom. A cross-section of
protrusion 351 and blade 352 is shown in FIG. 8D.
[0050] As shown in FIG. 8B, regenerative stator 370 may include a
plurality of protrusions 371 defining a plurality of channels 372
therebetween. Adjacent channels 372 may be connected via
intervening channels 373. A cross-section of protrusion 371 and
channel 372 is shown in FIG. 8D. Each channel 372 may include a
first portion 372a and a second portion 372b. First portion 372a
may be slightly wider than a width of protrusion 351, for example,
to prevent the flow of a substance therebetween. Thus, in
operation, any substance may be substantially contained in second
portion 372b. Second portion 372b may have any suitable
cross-sectional shape to accommodate substance flow, for example, a
curved or oval-like shape.
[0051] As shown in FIGS. 8C and 9, each blade 352 may be placed in
one of channels 372 such that protrusion 351 is disposed in first
portion 372a, and that blade 352 extends into second portion 372.
Each set of blades 352 and channels 372 may include a corresponding
inlet 391 and outlet 392 which may or may not be the same as
intervening channels 373.
[0052] In operation, blade 352 may rotate relative to channel 372.
A substance may enter second portion 372b of channel 372 via inlet
391. Blade 352 may then cause the substance to flow in the same
direction as the rotation of blade 352, for example, in a
substantially oval-like and/or spiral-like pattern as a consequence
of the gas gaining momentum and moving in a tangential direction to
the rotating blade 352 but being constrained by the channel 372.
The substance may then exit second portion 372b of channel 372 via
outlet 392. The substance may then be sent to another blade 352 and
channel 372 combination, or may be exhausted from pump 1.
[0053] As shown in FIG. 9, dry stage 300 may have a plurality of
blade 352 and channel 372 combinations. Each combination of blades
352 and channels 372 may be disposed radially inward and/or outward
from other combinations of blades 352 and channels 372. Rotor 350
may be disposed on the same shaft 106 as blades 104 and cylinders
202. Each combination of blades 352 and channels 372 may exhaust
the substance from an outer combination to a combination disposed
radially inward. The inner-most combination may exhaust the
substance out of the pump 1, for example, to the atmosphere.
[0054] As shown in FIGS. 4A and 4B, one or more of turbomolecular
stage 100, drag stage 200, and dry stage 300 are disposed in a
single housing 10. If pump 1 includes more than one of
turbomolecular stage 100, drag stage 200, and dry stage 300, the
boundary between the stages may not be externally discernable
(i.e., a person viewing the exterior of the apparatus with only
their naked eye would not be able to visualize the boundary between
turbomolecular stage 100, drag stage 200, and dry stage 300). The
pump may have a single driving motor to rotate the sets of blades,
cylinders, or other components of turbomolecular stage 100, drag
stage 200, and dry stage 300. In some embodiments, pump 1 may have
one or more motors configured to drive one or more components of
one or more of turbomolecular stage 100, drag stage 200, and/or dry
stage 300.
[0055] One or more of turbomolecular stage 100, drag stage 200, and
dry stage 300 may be connected to each other without substantially
having transition portions. For example, outlet 103 of
turbomolecular stage 100 may be substantially the same as inlet 204
of drag stage 200. In another example, outlet 205 of draft stage
200 may be substantially the same as inlet 301 of dry stage 300. In
a further example, outlet 103 of turbomolecular stage 100 may be
substantially the same as inlet 301 of dry stage 300.
[0056] One or more of turbomolecular stage 100, drag stage 200, and
dry stage 300 of pump 1 may be disposed in a single room 3 of a
semiconductor processing facility, for example, as shown in FIG. 5.
One advantage of pump 1 may be that it is possibly more compact
than conventional pumps, providing savings with regards to space,
and also reducing the number of pumps and/or components for a
particular process, for example, a semiconductor manufacturing
process.
[0057] As shown in the example of FIG. 6, one or more of
turbomolecular stage 100, drag stage 200, and dry stage 300 of pump
1 may have a common controller 90 that controls each of one or more
of turbomolecular stage 100, drag stage 200, and dry stage 300.
Common controller 90 may be connected to one or more of
turbomolecular stage 100, drag stage 200, and dry stage 300 by a
controller connection 91. One or more of turbomolecular stage 100,
drag stage 200, and dry stage 300 may be associated with a
semiconductor processing tool 2.
[0058] In some examples, rather than having a wired connection, a
wireless link may provide communication between common controller
90 and one or more of turbomolecular stage 100, drag stage 200, and
dry stage 300.
[0059] One or more of turbomolecular stage 100, drag stage 200, and
dry stage 300 of pump 1 may share common connections. For example,
one or more of turbomolecular stage 100, drag stage 200, and dry
stage 300 may share a common power connection. Power connection may
provide electrical power to one or more of turbomolecular stage
100, drag stage 200, and dry stage 300 so as to power one or more
motors associated with turbomolecular stage 100, drag stage 200,
and/or dry stage 300. This connection may also be fed through the
remote controller 90 to condition power before directing it to one
or more of turbomolecular stage 100, drag stage 200, and dry stage
300 of pump 1. In various embodiments, pump 1 may include any
suitable connections, for example, a nitrogen connection, a water
connection, and/or a dry air connection.
[0060] The invention may have several advantages. For example, the
invention may operate at a greater efficiency than multiple pumps
configured to transition the substance flow at the specified
ranges. In another example, conductance losses present during the
use of multiple pumps may be minimized and/or substantially
eliminated, for example, due to a reduction in the length of the
substance flow paths. In another example, the invention may take up
less space than multiple pumps and require less energy, important
advantages in an industry where space and power consumption is at a
premium. In a further example, because the exhaust from the
apparatus may be greater than or equal to about 100 millibar,
double containment of the apparatus may not be necessary as any
sub-atmospheric leaks may be inwards.
[0061] The invention may overcome several problems. For example,
each pump for each stage in a conventional machine may be delivered
separately. When delivered, the pressure in the chambers of each of
these pumps may be at atmospheric pressure. To operate the chamber,
the pressure in each chamber may be lowered to the proper operating
pressure. While one option is to initially run the rotor in each
chamber using a large motor, such an option is undesirable as it
may overheat the rotor. Another option is to at least initially use
another pump (e.g., a lock load pump) to reduce the pressure of the
chamber. Once the inlet pressure in the chamber of each pump is
below about 100 millibars (e.g., below about 10 millibars), the
pump may operate unassisted. By integrating the various stages of
the pump into a single pump, it may eliminate the need for the
additional pump, for example, if the pump already exhausts to
atmospheric pressure, allowing the pump to start and operate
completely unassisted. In the alternative, if the pump exhausts to
a pressure less than atmospheric pressure, only one additional pump
may be necessary, as opposed to one pump for each stage of a
conventional machine.
[0062] In another example, discrepancies in size between a
conventional turbomolecular pump, a conventional drag pump, and a
conventional dry pump prevented their combination into a single
pump. For example, there were large differences in the dimensions
of shafts in the conventional turbomolecular pump, conventional
drag pump, and conventional dry pump. Advances made in the dry
pump, for example, in the dry stage shown in FIGS. 8A, 8B, 8C, and
8D, have resulted in a more compact dry stage that may be
configured to be more readily combined with a turbomolecular stage
and/or drag stage.
[0063] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure described
herein. This, it should be understood that the invention is not
limited to the subject matter discussed in the specification and
shown in the drawings. Rather, the present invention is intended to
include modifications and variations.
* * * * *