U.S. patent application number 10/171494 was filed with the patent office on 2004-02-05 for megasonic cleaner and dryer system.
Invention is credited to Hosack, Chad M., Patel, Pankaj T., Standt, Raoul.
Application Number | 20040020512 10/171494 |
Document ID | / |
Family ID | 27404512 |
Filed Date | 2004-02-05 |
United States Patent
Application |
20040020512 |
Kind Code |
A1 |
Hosack, Chad M. ; et
al. |
February 5, 2004 |
Megasonic cleaner and dryer system
Abstract
An apparatus for cleaning a substrate includes a bearing
assembly, a tubular shaft, a substrate support, a process bowl, and
a dispenser. The tubular shaft has an upper end and a lower end.
The lower end is rotatably mounted to the bearing assembly. The
shaft provides an area through which cleaning liquid can be
directed. The substrate support has a lower region connected to the
tubular shaft and an upper region that supports the substrate. The
process bowl surrounds and is spaced outwardly from the substrate
support. The process bowl has a slot in an outer wall that receives
a robot arm that positions the substrate on the substrate support
and that withdraws the substrate from the substrate support. The
dispenser has an outlet that directs liquid through the area,
toward the upper region. The dispenser is positioned beneath the
upper region.
Inventors: |
Hosack, Chad M.; (Dana
Point, CA) ; Standt, Raoul; (Newport Beach, CA)
; Patel, Pankaj T.; (Corona, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
27404512 |
Appl. No.: |
10/171494 |
Filed: |
June 12, 2002 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60297736 |
Jun 12, 2001 |
|
|
|
60304920 |
Jul 11, 2001 |
|
|
|
60316725 |
Aug 30, 2001 |
|
|
|
Current U.S.
Class: |
134/1.3 ;
134/148; 134/153; 134/33; 134/902; 134/95.2; 134/95.3 |
Current CPC
Class: |
Y10S 134/902 20130101;
H01L 21/67034 20130101; H01L 21/67051 20130101 |
Class at
Publication: |
134/1.3 ; 134/33;
134/153; 134/902; 134/148; 134/95.2; 134/95.3 |
International
Class: |
B08B 003/02 |
Claims
What is claimed is:
1. An apparatus for cleaning a substrate, the apparatus comprising:
a bearing assembly; a tubular shaft having an upper end and a lower
end, the lower end rotatably mounted to the bearing assembly, the
tubular shaft providing a dispensing area through which cleaning
liquid can be directed; a substrate support having a first portion
connected to the tubular shaft and a second portion for supporting
the substrate; a process bowl surrounding and spaced outwardly from
the substrate support, the process bowl having a slot in an outer
wall configured to receive a robot arm that positions the substrate
on the substrate support and that withdraws the substrate from the
substrate support; and a dispenser having an outlet that directs
liquid through the dispensing area toward a lower surface of the
substrate, the dispenser positioned beneath the upper portion.
2. The apparatus of claim 1, further comprising an assembly plate,
wherein the substrate support is rotatably coupled to the assembly
plate at a fixed elevation.
3. The apparatus of claim 2, further comprising a mounting bracket
having a first end connected to the assembly plate and a second end
proximate the dispensing area, the second end coupled to the
dispenser.
4. The apparatus of claim 3, wherein the dispenser is connected to
the mounting bracket.
5. The apparatus of claim 1, wherein the tubular shaft has an inner
diameter of at least about four inches.
6. An apparatus for cleaning a substrate comprising: a single
bearing assembly; a tubular shaft having an upper end and a lower
end, the lower end being coupled to the single bearing assembly; a
bottom-side fluid dispenser for directing fluid through the tubular
shaft; and a substrate support having a horizontally extending
portion and a plurality of spaced posts, the horizontally extending
portion having a hole that provides unobstructed access for fluid
directed through the bottom-side fluid dispenser, the horizontal
portion coupled with the upper end of the tubular shaft, the
plurality of spaced posts extending upwardly from an upper surface
of the horizontal portion, the posts being configured to engage
spaced peripheral portions of the substrate to support the
substrate.
7. The apparatus of claim 6, wherein the posts are spaced to
receive a portion of a robot arm that positions the substrate on
the substrate support and removes the substrate from the substrate
support.
8. The apparatus of claim 6, further comprising a cylindrical band
interconnecting the posts.
9. The apparatus of claim 8, wherein the cylindrical band is spaced
from an upper end of the posts so that fluid applied to a lower
surface of the substrate can flow radially outwardly through spaces
defined by an upper edge of the cylindrical band, the substrate
lower surface, and adjacent posts.
10. The apparatus of claim 8, wherein the cylindrical band is
spaced from the upper surface of the horizontal portion so that
fluid applied to the lower surface of the substrate can flow
radially outwardly through a space defined by an upper side of the
horizontal portion, a lower edge of the cylindrical band, and
adjacent posts.
11. An apparatus for cleaning and drying a generally flat substrate
comprising: a rotatable support for supporting a substrate, the
support having an upper portion for supporting the substrate and a
tubular shaft defining a dispensing area through which cleaning
fluid can be directed; a process bowl surrounding the support and
spaced outwardly therefrom, the process bowl having a slot through
which the substrate may be moved; a fluid dispenser for applying
fluid to a lower surface of the substrate through the dispensing
area; a transmitter configured to be spaced above the substrate,
and configured to propagate megasonic energy through a meniscus
formed on the substrate.
12. The apparatus of claim 11, further comprising: a substrate
drying assembly configured to be spaced above the substrate, the
substrate drying assembly including an outlet for applying fluid to
an upper surface of the substrate and an outlet for applying a
drying vapor to the upper surface of the substrate, the substrate
drying assembly configured to be extendable into and out of the
process bowl; and a controller configured to cause the transmitter
and the substrate drying assembly to be extended from the edge of
the process bowl to a position over the surface of the substrate,
and to cause the transmitter and the substrate drying assembly to
be retracted from a position over the surface of the substrate to
the edge of the process bowl.
13. The apparatus of claim 12, further comprising an assembly plate
wherein the substrate support is rotatably mounted to the assembly
plate at a fixed elevation.
14. The apparatus of claim 12, further comprising a stationary
dispenser having an outlet, the stationary dispenser directing
fluid through said dispensing area.
15. The apparatus of claim 12, further comprising a mounting
bracket having a first end connected to the assembly plate and
having a second end that extends near the dispensing area, the
mounting bracket being configured to position the stationary
dispenser.
16. A method of cleaning a substrate, the method comprising:
providing an assembly plate, a bearing assembly mounted on the
assembly plate, a tubular shaft having an upper portion, a lower
portion coupled to the bearing assembly for rotation, and a
dispensing area, a substrate support having an upper portion for
supporting the substrate and a lower portion coupled to the upper
portion of the tubular shaft, at least a portion of the upper
portion of the substrate support being located in the process bowl,
a process bowl spaced outwardly from the substrate support, the
process bowl having a slot in an outer wall configured to receive a
robot arm that positions the substrate on the substrate support and
that withdraws the substrate from the substrate support, the
process bowl mounted on the assembly plate, a dispenser coupled
with the assembly plate, the dispenser capable of directing
cleaning fluid toward a bottom surface of the substrate, the
dispenser at least partially located in the tubular shaft;
positioning the substrate on the upper portion of the substrate
support; and directing fluid unobstructed from the dispenser
through the dispensing area onto a bottom surface of the
substrate.
17. A method of cleaning a substrate in a cleaning apparatus having
a megasonic cleaning assembly, a bearing assembly, a vertically
fixed substrate support having an upper portion and a tubular
shaft, and a process bowl, the substrate support mounted on the
bearing assembly, the upper portion of the substrate support
supporting the substrate, the tubular shaft providing an area for
locating a first fluid dispenser beneath the upper portion to
dispense liquid onto a lower surface of the substrate, the process
bowl surrounding and spaced outwardly from the upper portion of the
substrate support, the process bowl having a slot in an outer wall,
the process bowl being configured to receive a second liquid
dispenser, and an assembly plate, the bearing assembly and the
process bowl mounted on the assembly plate, the method comprising:
positioning the substrate on the substrate support; rotating the
substrate on the chuck; applying liquid to the lower surface of the
substrate unobstructed through the first dispenser and through the
dispensing area of the tubular shaft; applying liquid to the upper
surface of the substrate through the second dispenser; and applying
megasonic energy to substrate through the megasonic cleaning
assembly.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/297,736, filed Jun. 12, 2001, and claims the
benefit of U.S. Provisional Application No. 60/304,920, filed Jul.
11, 2001, and also claims the benefit of U.S. Provisional
Application No. 60/316,725, filed Aug. 30, 2001, the entirety of
all of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to an apparatus and method for
cleaning semiconductor substrates or other such items requiring
extremely high levels of cleanliness.
[0004] 2. Description of the Related Art
[0005] Semiconductor substrates can be cleaned by propagating
acoustic energy, such as megasonic energy, into a layer of cleaning
solution on the surface of the substrate. Megasonic cleaning
systems use this cleaning solution layer to propagate megasonic
energy, i.e. acoustic energy at frequencies much greater than
ultrasonic. This energy is directed toward the surface of the
substrate and thereby removes, safely and effectively, particles
from the substrate surface without the negative side effects
associated with ultrasonic cleaning.
[0006] In the past, such cleaning systems have been designed to
process substrates in batches, typically cleaning 25 substrate at
once. The benefit of this batch cleaning became less important as
substrate size increased because single substrate capacity
increased. Also, substrate processors began working with more
delicate devices, which required more careful handling than was
possible in batch cleaning. The greater value per substrate and the
more delicate nature of the devices produced on the substrates
created a great need for single wafer processing equipment.
[0007] Single substrate megasonic cleaning equipment for processing
the larger substrates carrying more delicate devices have been
developed to meet this need. One such single substrate cleaning
system incorporates a probe and a transducer and is described in
U.S. Pat. No. 6,140,744 and commercially available from Verteq Inc.
of Santa Ana, Calif. One cleaning apparatus described therein
comprises an elongate probe configured to propagate megasonic
energy to a surface of a substrate by way of a meniscus of liquid
extending between the probe and the substrate. Because the energy
is transmitted through a meniscus of liquid, the process is a "wet"
process and it requires the probe to be positioned very close to
the substrate surface.
[0008] After this "wet" cleaning process, the substrate must be
dried prior to further processing. Various methods of drying the
substrate have been tried and have generally involved spinning the
substrate and thereby forcing the liquid off the substrate surface
via centrifugal forces arising from the spinning. Unfortunately,
this drying method has its drawbacks, such as the tendency of
liquid on a surface to leave behind residue, e.g. water spots. In
the past, such spots were not of great concern to the simpler
devices being produced on the substrates. However, as already
mentioned, the devices processed on substrates have become more
delicate, and therefore more sensitive to contaminants of all
kinds, including water spots. Moreover, substrate processors have
become more aware of sources of process variation, which translate
into variation in performance of the devices and yield variation.
One such source of these variations is contaminants, including
drying residue. Therefore, careful control of the drying conditions
has been investigated by some.
[0009] European patent application publication EP0905747A1 to IMEC
discloses a drying apparatus that exploits rotational and Marangoni
effects to improve drying performance. As mentioned above, the
rotation of the substrate subjects the liquid to centrifugal
forces, which tend to force the liquid from the center of the
substrate toward its edge, and ultimately off of the surface.
Simultaneously, a surface tension reducing vapor creates the so
called Marangoni effect that reduces the tendency of the liquid to
adhere to the substrate surface, i.e. reduces the liquid surface
tension. This reduces the tendency of the liquid to remain on the
substrate surface long enough to evaporate from the surface and
therefore helps to produce a residue free drying process. While the
IMEC apparatus has achieved satisfactory substrate drying results
in the laboratory, the concept has not been implemented into a
commercial application.
[0010] Another issue presented by wet spin cleaning and drying of
substrates is the containment and disposal of the process liquids
involved, for example, various acids, bases, solvents, and
de-ionized water. Some of these liquids may harm workers or damage
other equipment in the vicinity of the cleaning apparatus if the
workers or equipment come into contact with the process liquids.
Thus, full containment and removal of the process liquids is
necessary to maintain a safe working environment and protect
valuable equipment.
[0011] However, a critical design consideration for any machine in
substrate processing is process time, or through-put. This is in
part because substrate processing must be done in very clean, and
thus very expensive, fabrication facilities. As a result, substrate
processors prefer to maximize the output of existing facilities
rather than expanding those facilities or building new ones. Thus,
fast through-put is preferred.
[0012] Therefore, a need exists for an improved cleaning method and
apparatus that will improve the drying performance in a single
wafer processing application and will improve throughput for
performing substrate cleaning and drying operations.
SUMMARY OF THE INVENTION
[0013] In one embodiment, an apparatus for cleaning a substrate
includes a bearing assembly, a tubular shaft, a substrate support,
a process bowl, and a dispenser. The tubular shaft has an upper end
and a lower end. The lower end is rotatably mounted to the bearing
assembly. The shaft provides an area through which cleaning liquid
can be directed. The substrate support has a lower region connected
to the tubular shaft and an upper region that supports the
substrate. The process bowl surrounds and is spaced outwardly from
the substrate support. The process bowl has a slot in an outer wall
that receives a robot arm that positions the substrate on the
substrate support and that withdraws the substrate from the
substrate support. The dispenser has an outlet that directs liquid
through the area, toward the upper region. The dispenser is
positioned beneath the upper region.
[0014] In another embodiment, an apparatus for cleaning a substrate
includes a single bearing assembly, a tubular shaft, a bottom-side
fluid dispenser, and a substrate support. The tubular shaft has an
upper end and a lower end. The lower end of the tubular shaft is
coupled to the single bearing assembly. The bottom-side fluid
dispenser directs fluid through the tubular shaft. The substrate
support has a horizontally extending portion and a plurality of
spaced posts. The horizontally extending portion has a hole that
provides unobstructed access for fluid directed through the
bottom-side fluid dispenser. The horizontal portion is coupled with
the upper end of the tubular shaft. The plurality of spaced posts
extends upwardly from an upper surface of the horizontal portion.
The posts engage spaced peripheral portions of the substrate to
support the substrate.
[0015] In another embodiment, an apparatus for cleaning and drying
a generally flat substrate includes a rotatable support, a process
bowl, a fluid dispenser, and a transmitter configured to be spaced
above the substrate. The rotatable support has an upper portion
that supports the substrate and a tubular shaft that defines a
dispensing area through which cleaning fluid can be directed. The
process bowl surrounds the support and is spaced outwardly
therefrom. The process bowl has a slot through which the substrate
may be moved. The fluid dispenser applies fluid to a lower surface
of the substrate through the dispensing area. The transmitter is
configured to be spaced above the substrate and to propagate
megasonic energy through a meniscus formed on the substrate.
[0016] In another embodiment, a method of cleaning a substrate
provides an assembly plate, a bearing assembly mounted on the
assembly plate, and a tubular shaft. The tubular shaft has an upper
portion, a lower portion coupled to the bearing assembly for
rotation, and a dispensing area. Also provided is a substrate
support, a process bowl, and a dispenser coupled with the assembly
plate. An upper portion of the substrate support supports the
substrate, and a lower portion of the substrate support is coupled
to the upper portion of the tubular shaft. At least a portion of
the upper portion of the substrate support is located in the
process bowl. The process bowl is spaced outwardly from the
substrate support. The process bowl has a slot in an outer wall
configured to receive a robot arm that positions the substrate on
the substrate support and that withdraws the substrate from the
substrate support. The process bowl is mounted on the assembly
plate. The dispenser is coupled with the assembly plate. The
dispenser directs cleaning fluid toward a bottom surface of the
substrate. The dispenser is at least partially located in the
tubular shaft. The substrate is positioned on the upper portion of
the substrate support. Fluid is directed unobstructed from the
dispenser through the dispensing area onto a bottom surface of the
substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a schematic isometric view of one embodiment of
the substrate cleaning apparatus.
[0018] FIG. 2 is a schematic top view of one embodiment of a
processing chamber showing a liquid dispenser location map for the
substrate cleaning apparatus of FIG. 1.
[0019] FIG. 3A is a cross-sectional view of one embodiment of the
processing chamber of FIG. 2 taken along section lines 3A-3A. FIG.
3B is a cross-section view of one embodiment of the processing
chamber of FIG. 2 taken along section lines 3B-3B.
[0020] FIG. 4A is a schematic top view of the multi-dispenser
rinsing configuration of FIG. 1.
[0021] FIG. 4B is a schematic side view of a multi-dispenser
rinsing configuration of the cleaning apparatus of FIG. 4A.
[0022] FIG. 5 is a top view of one embodiment of the substrate
cleaning apparatus.
[0023] FIG. 6 is a isometric view of one embodiment of the
substrate cleaning apparatus with the component cover removed and a
portion of the removable decktop cut away.
[0024] FIG. 7 is side elevation view of one embodiment of the
substrate chuck and servomotor assembly.
[0025] FIG. 8 is a top view of one embodiment of the substrate
chuck and servo motor assembly of FIG. 7.
[0026] FIG. 9A is an isometric view of one embodiment of the
substrate chuck assembly of the substrate cleaning system.
[0027] FIG. 9B is an isometric view of one embodiment of an open
center chuck of the substrate chuck assembly shown in FIG. 9A.
[0028] FIG. 10 is an isometric view of one embodiment of the
process bowl of one embodiment of the substrate cleaning
apparatus.
[0029] FIGS. 11A-11C are side elevation views of one embodiment of
the moveable splash guard in various process positions with the
process bowl shown in phantom.
[0030] FIG. 12 is a partial view of one embodiment of the substrate
chuck and moveable splash guard with the splash guard shown in
cross-section.
[0031] FIG. 13 is a partial top view of one embodiment of the
processing chamber of the substrate cleaning apparatus showing the
trajectory of cleaning liquids.
[0032] FIG. 14 is an isometric view of one embodiment of a
mesh-type splash guard.
[0033] FIG. 15 shows a drive module in isometric view.
[0034] FIG. 16 shows an isometric view of one embodiment of the
drive module for a substrate drying assembly.
[0035] FIG. 17 shows a control strategy applied by the drive module
for one processing method.
[0036] FIG. 18 shows a control strategy implemented by the drive
module for another example processing method.
[0037] FIG. 19 shows a control strategy implemented by the drive
module for another example processing method applied to the drying
assembly.
[0038] FIG. 20 shows a flow chart of one exemplary control strategy
for cleaning and drying using the cleaning apparatus of the present
invention.
[0039] FIG. 21 shows a two-dimensional graph of patterned and
blanket substrate process windows that relate the drying head
retraction rate to the rotational speed of the substrate.
[0040] FIG. 22A shows a two-zone drying head retraction rate
map.
[0041] FIG. 22B shows a three-zone drying head retraction rate
map.
[0042] FIG. 23 shows a side elevation view of a stackable
configuration of one embodiment of the substrate cleaning
apparatus.
[0043] FIG. 24 shows a schematic perspective view of one embodiment
of the stackable configuration substrate cleaning apparatus in a
mounting system from the front side of the apparatus.
[0044] FIG. 25 shows a schematic perspective view of one embodiment
of the stackable configuration substrate cleaning apparatus in the
mounting system from the rear side of the apparatus.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0045] FIGS. 1-6 illustrate one embodiment of a megasonic energy
cleaning and drying apparatus 100 made in accordance with the
present invention with a containment plenum 102 below and
supporting an assembly main reference plate (shown in FIGS. 6-8,
9-11C), which is nested underneath a removable decktop 104. A
process bowl 106 is mounted within the containment plenum 102 and
extends through a cut-out in the decktop 104. The bowl 106, which
is preferably cylindrical or any other suitable shape, has a
vertical portion that extends through the decktop cut-out to a
desired height. The decktop cut-out is preferably the same shape as
the bowl 106.
[0046] A plurality of dispensers 108 are mounted to the vertical
portion of the bowl 106, i.e. the bowl side wall, and extend toward
the bowl's center. Each of the dispensers 108 has an outlet through
which fluid is dispensed. These dispensers 108 may be pivotably
mounted to brackets which have the shape of an inverted "J", the
inside curve of which is configured to receive the top surface of
the bowl. In this way, the elevation of the dispenser may be fixed.
The dispensers 108 are connected to gas or liquid supply lines (not
shown) which provide cleaning media to the surface desired to be
cleaned. The position of the dispensers with respect to the other
components is relates to controlling the cleaning operation in some
embodiments, and will be discussed in more detail below.
[0047] A substrate chuck 110 of a substrate chuck assembly 112 is
also positioned within the process bowl 106 and is configured to
receive and support a substrate 114 during processing in the
cleaning apparatus 100 (See FIGS. 7, 9B and 12). The chuck 110 and
the dispensers 108 are positioned relative to one another so that
when the substrate 114 is positioned on the chuck 110 the cleaning
media dispensed by the dispensers 108 may be directed onto a
surface of the substrate 114. The chuck 110 is rotatable with
respect to the process bowl, as discussed in more detail below in
connection with FIGS. 7 and 8. As shown in FIGS. 1 and 6, the
substrate is rotated on the chuck 110 as indicated by arrows 116
during processing in the apparatus 100. The direction of the arrows
116 is not intended to indicate that the substrate 114 may be
rotated in only one direction. The substrate may be rotated in the
direction opposite to that shown in FIGS. 1 and 6 in accordance
with the wafer cleaning and drying assembly 100.
[0048] The side wall of the bowl 106 near the rear-most portion of
the bowl comprises at least one aperture. These apertures provide
access to the processing chamber of the process bowl 106 for any of
a number of processing devices, e.g., the aperture provides access
for a cleaning assembly 118 and/or a substrate drying assembly 120,
also referred to herein as the drying assembly 120. There may also
be two or more apertures in the rear portion sidewall, one to
provide access for the drying assembly 120 and one to provide
access for the cleaning assembly 118. Other suitable processing
devices can also be incorporated into the apparatus 100.
[0049] The cleaning assembly 118 may include a rod-like probe
coupled to a megasonic transducer. As mentioned above, a rod-like
probe coupled to a megasonic transducer is described in more detail
in U.S. Pat. No. 6,140,744, which is hereby incorporated by
reference. As described therein, a probe 122 is configured to
propagate megasonic energy to the surface of the substrate 114 by
way of a meniscus of liquid extending between the probe and the
substrate 114 to loosen particles on the substrate. The probe 122
must be positioned close enough to the substrate 114 so that a
meniscus of liquid extends between the probe and the substrate.
Preferably this distance is about one-tenth of an inch, or about
2.5 millimeters, creating a meniscus of the same height except that
the liquid also covers a small lower edge of the probe. In one form
of the invention, the liquid forming the meniscus is applied to the
surface of the substrate 114 by suitable dispensers 108. Although a
rod-like probe is illustrated in connection with the preferred
embodiment described herein, a transmitter of any suitable shape
will also work.
[0050] Control of the liquid interface between the probe 122 and
the substrate 114 (the meniscus) can enhance the cleaning
performance of the cleaning and drying apparatus 100. There are
several variables which influence the amount of energy that may be
propagated through the liquid to the surface of the substrate 114,
including the height of the meniscus, the absence or presence of
surface waves impacting the probe 122, the fluid flow properties of
the cleaning media, the ability to dispense the cleaning media in a
pulsing (i.e., a flow-rate variable) fashion, the frequency of the
acoustic energy applied to the probe, the availability of a
dispenser to apply a loading media to the probe 122 to dampen the
energy of the probe, and other factors.
[0051] The acoustic energy propagated through the meniscus can be
controlled by carefully positioning the cleaning liquid dispensers
so that the liquid that they dispense does not substantially
interfere with the operation of the probe. Such interference can
occur, for example, when the thickness of the meniscus proximate
the probe varies substantially. This can occur, for example, if
surface waves are created in the liquid meniscus proximate the
probe 122. One way to reduce the interference of the dispensed
liquid with the propagation of energy is to position the dispensers
so that the dispenser nozzles dispense the cleaning liquid onto a
portion of the substrate that is not near the probe. The dispensers
108 may be positioned at any desired location around the
circumference of the bowl 106, and their location may be defined as
a number of degrees between 0 and 360 with respect to a reference
location, such as the probe 122 forming a part of the cleaning
assembly 118. More specifically, if the probe 122 is the reference
location, then 90 degrees is the location that is one-quarter the
way around the bowl 106 from the probe in the clockwise direction
as viewed from the top.
[0052] Propagation of energy through the meniscus can be controlled
by creating a liquid dispenser location map for the substrate
cleaning apparatus 100. A dispenser location map can be created by
dividing the 360 degree range of cleaning dispenser locations
around the circumference of the bowl 106 into at least two
circumferential zones. The circumferential zones may or may not be
physically distinct features of the process bowl 106. In one
preferred embodiment, the range of nozzle positions is divided into
five circumferential zones (see FIG. 2). A zone 150 can include the
position of the probe 122, i.e., the reference location at zero
degrees. The zone 150 could extend clockwise around the bowl 106
from about 315 degrees to about 90 degrees. A zone 152 can be
located adjacent to the zone 150, extending clockwise around the
bowl 106 from about 270 degrees to about 315 degrees. A zone 154
can be located adjacent to the zone 152, extending clockwise around
the bowl 106 from about 235 degrees to about 270 degrees. A zone
156 can be located adjacent to the zone 154, extending clockwise
around the bowl 106 from about 135 degrees to about 235 degrees. A
zone 158 is located between the zone 156 and the zone 150,
extending from about 90 degrees to about 135 degrees. In one
embodiment, the cleaning fluid dispensers 108 are positioned in any
of the zones 152, 154, 156, or 158. More preferably, the cleaning
fluid dispensers 108 are positioned in any of zones 154, 156, or
158. Still more preferably, the cleaning fluid dispensers are
positioned in either zone 154 or zone 158.
[0053] In another variation, the zone 150 can be subdivided into
two sub-zones. The first sub-zone extends clockwise from about 315
degrees to about 45 degrees, and the second sub-zone extends from
about 45 degrees to about 90 degrees. In this embodiment, the
cleaning fluid dispensers 108 are positioned in any of the zones
152, 154, 156, 158, or the second sub-zone of the zone 150
extending from about 45 degrees to about 90 degrees. More
preferably, the cleaning fluid dispensers 108 are positioned in any
of zones 154, 156, or 158. Still more preferably, the cleaning
fluid dispensers are positioned in either zone 154 or zone 158.
[0054] The cleaning fluid dispensers 108 dispense liquid in a
direction that is preferably generally perpendicular to a vertical
plane passing through the longitudinal axis of the probe 122.
However, the dispensers may be made adjustable to a range of
dispense angles with respect to the probe. For example, the
dispensers 108 can be rotated about a vertical axis passing through
the base of the dispenser 108. The range of rotation can be about
thirty degrees to the right of and about thirty degrees to the left
of a horizontal line perpendicular to the vertical plane passing
through the probe 122. This may improve the control of the meniscus
in one or more of the radial zones 152-158. For example, in the
zone 152, an angle of thirty degrees to the right of the horizontal
line perpendicular to the vertical plane passing through the probe
122 may be preferred.
[0055] As shown in FIGS. 2 and 3A, a transmitter-loading dispenser
109 can be configured to dispense liquid directly onto the probe
122. The dispenser 109 is preferably located in zone 150. Liquid
applied to the probe 122 through the dispenser 109 preferably is
collected in a drain or in a re-circulation basin (not shown). The
liquid applied through the dispenser 109 can be either de-ionized
water, or one of many known chemical treatments, such as an ammonia
peroxide mixture. The dispenser 109 can be used to dampen the
megasonic energy in the probe 122. This technique is referred to as
"loading" the probe. The probe 122 is preferably loaded by applying
liquid to it from the dispenser 109 at a radial position between
the edge of the substrate and the inner wall of the process bowl
106. The cleaning apparatus 100 preferably has control systems
capable of either loading or not loading the probe, as required.
Loading the probe draws some of the megasonic energy out of the
probe and directs it away from the surface of the substrate 114.
This may improve the cleaning because some devices formed on the
surface of the substrate 114 may be too sensitive to clean without
dampening. The application of liquid from the dispenser 109 can
reduce damage to such devices while still enabling cleaning for
some applications. This technique can be used in combination with
other techniques, such as changing the applied power, frequency,
and energy directivity of the probe, to control damage. By applying
liquid to the probe from the dispenser 109, the throughput of the
substrate cleaning process can also be reduced because the time
required for the probe 122 to contact the liquid on the surface of
the substrate can be reduced.
[0056] The dispenser 109 in the apparatus 100 provides several
advantages. One advantage related to the probe dampening described
above involves tuning the probe 122. Each probe has slightly
different cleaning performance. As a result, prior to installing
the probe into the apparatus 100, the probe 122 preferably is
tuned. Furthermore, a specific substrate type used by a customer
may be very sensitive to the energy applied to it, and, as a
result, too much energy could cause damage to that type of
substrate. Accordingly, the probe 122 may need to be tuned to the
customer's substrate type. Probe tuning involves operating the
probe at a variety of frequency to find the frequency that provides
the best cleaning performance. Sometimes, however, adjusting the
frequency of the power applied to the probe 122 does not provide
enough tuning resolution, i.e., adjacent frequency steps are too
large to produce the desired cleaning performance. In that case,
the probe dampening technique described above can be used in
combination with frequency adjustments to properly tune the
probe.
[0057] As mentioned above, it is desirable to reduce throughput for
cleaning substrates on the apparatus 100. As discussed in more
detail below, in connection with FIG. 20, the probe is extendable
into and retractable out of the bowl 106. The dispenser 109
advantageously improves throughput by enabling the probe 122 to
apply megasonic energy to the substrate while it is being extended
over the substrate. By applying liquid to the probe 122 from the
dispenser 109, the amount of power transmitted through the meniscus
can be scaled to prevent damage to delicate structures on the
surface, to account for the lower area of contact between the probe
and the liquid, or to otherwise scale the effective power as
needed. This improves cleaning efficiency, cleaning throughput,
and, therefore, the cost of ownership associated with the apparatus
100.
[0058] Another advantage provided by adding the dispenser 109 is
that liquid from the dispenser 109 can be used to rinse the probe
122. By rinsing the probe 122, contaminants picked up by the probe
122 during the cleaning of a prior substrate 114 can be reduced
prior to the cleaning of a subsequent substrate 114. By reducing
contaminants on the probe 122, cleaning of the subsequent substrate
114 by the apparatus 100 will be more effective and more
efficient.
[0059] The meniscus may further be controlled by carefully
controlling the fluid flow properties of the cleaning media
directed at the substrate 114 by the nozzles of the dispensers 108.
These properties are controlled by selecting a preferred nozzle
inner diameter. Varying the nozzle diameter affects the fluid flow
of the cleaning media. For example, for a cleaning liquid supplied
to the nozzle at a constant pressure, smaller nozzles tend to
produce higher cleaning fluid velocities. The preferred fluid
pressure for cleaning liquid supplied to the nozzle is in a range
between about 2 and about 30 pounds per square inch, or between
about 13,700 newton per square meter and about 206,800 newton per
square meter. Higher fluid velocities tend to interfere more with
the cleaning capability of the probe. Thus, the nozzle size
preferably is controlled. In order to clean adequately, the nozzle
size is preferably greater than about 0.125 inches, or about 3.2
millimeters, in one embodiment. The cleaning media dispenser nozzle
size is preferably greater than about 0.25 inches, or about 6.4
millimeters, in another embodiment. The cleaning media dispenser
nozzle size is most preferably about 0.25 inches, or about 6.4
millimeters.
[0060] As mentioned, the flow velocity of the liquid exiting the
nozzle increases with smaller nozzle sizes for the same volumetric
flow rate. Because the distance between the nozzle and the
substrate is fixed, varying the nozzle size may require that the
trajectory of the liquid be varied. Thus, for a 0.125 inch nozzle,
the trajectory of the nozzle and the liquid as it initially exits
the nozzle is approximately fifteen degrees below the horizon. By
contrast, for a 0.25 inch nozzle, the trajectory of the nozzle and
initial trajectory of the liquid is between about thirty degrees
and about forty-five degrees above the horizon, see FIG. 3B.
[0061] Another variable which can increase cleaning efficiency is
the capability to pulse the application of cleaning media to the
substrate. This pulsing preferably involves turning the dispensing
nozzle on and off at regular intervals. More generally, it could
involve varying the volumetric flow rate of the media exiting the
dispenser. For a given dispenser geometry, and for liquid cleaning
medium, the flow velocity is adjusted by varying the fluid
pressure. Thus, the dispensers preferably can be controlled to
apply liquid to the substrate in a pulsing manner. In the pulsing
mode, the cleaning media dispensing nozzles preferably are cycled
at a frequency between 0.1 hertz and 0.5 hertz, i.e., a period
ranging from 2 seconds to 10 seconds. Alternately, the fluid
pressure could be varied between, for example, between about 30
pounds per square inch, or about 206,900 newton per square meter,
and about 2 pounds per square inch, or about 13,700 newton per
square meter. More preferably, the pressure could be varied between
about 10 pounds per square inch, or about 69,000 newton per square
meter, and about 2 pounds per square inch, or 13,700 newton per
square meter. Pulsing could be achieved using other techniques. For
example, pulsing application of fluid to the substrate could also
be achieved by varying the fluid flow rate between the preferred
maximum flow rate and a lesser, non-zero flow rate.
[0062] Other variables which can be used to control the manner in
which acoustic energy propagates through the meniscus include the
height of the meniscus, the frequency of the energy applied to the
probe, and other factors. As discussed above, the frequency applied
to the probe 122 can be adjusted in order to tune the probe 122.
This process yields a preferred operating frequency for the probe
122 that might correspond to the highest cleaning efficiency. The
probe 122 can operate at a wide range of frequencies, for example,
between about 500 kilohertz ("kHz") and about 1.5 megahertz (MHz).
The probe 122 can also operate very well in a frequency range
between about 825 kHz and about 850 kHz. The probe 122 can also
operate very well within a frequency range from about 836 kHz to
about 844 kHz. The probe 122 can operate very well at about 836 kHz
or about 844 kHz. As discussed below in more detail, the apparatus
100 further comprises a controller 147, which is programmable to
apply megasonic energy to the probe at one or more of the frequency
ranges described above.
[0063] As discussed above, the preferred operating frequency of an
individual probe 122 can depend on several factors, for example,
the actual dimensions of the probe 122, the overall dimensions of
the entire cleaning assembly 118, the substrate application and
other factors. As discussed above in connection with loading the
probe 122, when the cleaning application involves substrates 114
carrying very delicate structures, the preferred operational
frequency of megasonic energy applied to the probe 122 can be
altered from the frequency corresponding to the highest cleaning
efficiency. This other frequency can reduce the possibility of the
probe 122 damaging delicate structures on the substrate 114.
[0064] FIGS. 4A and 4B illustrate another embodiment of the
apparatus 100. It may sometimes be desirable to apply a rinse to
the substrate 114, in addition to the cleaning and drying. While
the rinsing step can add to the throughput, a multi-dispenser
rinsing configuration can minimize the additional processing time.
As shown in FIG. 4A, a plurality of rinsing dispensers 111 are
mounted to the process bowl 106 and are configured to apply rinsing
liquid to the substrate 114. During the rinse, there generally is
no need to maintain a controlled meniscus. Therefore, a high
velocity rinsing process can be used. As shown in FIG. 4B, the
rinsing dispensers 111 in the high velocity rinsing process may be
oriented downwardly with respect to the horizon, for example, by
about fifteen degrees. The two rinsing dispensers 111
advantageously approximately doubles the volume of rinsing liquid
that is applied to the outer edge of the substrate 114 compared to
a single rinse dispenser configuration for each revolution of the
substrate. This decreases rinsing process time, where needed, and
therefore minimizes throughput of processes that require rinsing.
The rinsing dispensers 111 could also be positioned on the bowl 106
to dispense onto the center of the substrate 114.
[0065] The probe 122 is extendable into and retractable out of the
bowl 106 through one of the apertures in the side wall of the bowl
106. For example, as shown by the arrow 124, the assembly 118 is
movable in a radial direction. The assembly 118 preferably may be
extended outward from the rear-most side wall of the process bowl
106 until it reaches about the center or just beyond the center of
the substrate 114. On the other hand, when the assembly 118 is
retracted, most of the probe 122 is received beneath the cover 132.
As described in the above-noted U.S. Pat. No. 6,140,744, megasonic
energy applied to a transducer coupled to the probe 122 propagates
through the probe 122, and through the meniscus of liquid onto the
substrate 114 to loosen particles on the substrate 114 while the
substrate 114 is rotating.
[0066] In the preferred embodiment, the process bowl 106 also
comprises a second aperture for receiving drying assembly 120. The
assembly 120 may include a drying head 128, which is described in
greater detail in European Patent application publication
EP0905747A1. As described therein, the drying assembly 120 has a
substrate drying assembly support arm 130 mounted to be moveable
radially with respect to the substrate 114 into and out of a
position closely spaced above the upper surface (the device side)
of the substrate 114 supported on the chuck 110. The drying
assembly 120 includes an outlet that applies, or dispenses, liquid
to the surface of the substrate and also includes an outlet that
applies, or dispenses, tensioactive vapor to the surface of the
substrate 114. The drying vapor outlet is positioned radially
beyond the drying liquid outlet. The drying assembly 120 is
designed to be extendable through the rear-most side wall of the
process bowl 106 toward and just beyond the center of the
processing chamber of the process bowl 106. The drying assembly 120
also resides primarily under the cover 132 when retracted. The
operation of the drying assembly 120 and the cleaning assembly 118
can be carefully controlled in order to sufficiently clean the
substrate 114 at a satisfactory speed. This control is described in
connection with a method described below. The drying assembly 120
dries the surface of the substrate 114 through centrifugal action
and by displacing the processing liquids on the surface with a
tensioactive liquid that reduces the surface tension of the
processing liquids.
[0067] A moveable splash guard 134 is also located in the process
bowl 106, and is discussed in greater detail with respect to FIGS.
11A-13. In the preferred embodiment, the movement of splash guard
134 is generated by a plurality of supports that comprise front
support 136 and rear supports 138. As shown in FIG. 1, the support
136 extends through the decktop 104, while the supports 138 extends
through the rear cover 132. Of course it will be understood that
the support locations may be varied affecting the operation of the
splash guard 134.
[0068] Referring now to FIG. 2, a valve manifold and associated
piping 140 is provided to supply the liquid and/or gas which is
dispensed by the dispensers 108. The dispensers 108 each comprise
an outlet for directing the liquid and/or gas onto the surface of
the substrate 114 at a preferred location. The piping 140 resides
beneath the cover 132. The cleaning apparatus 100 also comprises an
exhaust and drain manifold 142 to carry away waste gases, liquids
and contaminants.
[0069] FIG. 6 shows a portion of the removable decktop 104 cut
away. A main reference plate 163 can be seen beneath the decktop
104. The megasonic probe 122, which is positioned at an elevation
above the substrate 114 when the substrate 114 is positioned within
the substrate chuck 110, is actuated by a megasonic probe drive
module 144. The drying head 128, also positioned at an elevation
above the substrate 114, similarly is actuated by a drying assembly
drive module 146. Both drive modules 144, 146 are mounted within
the cover 132 on the assembly main support plate 163, are
controlled by a controller 147, and are discussed in greater detail
below in connection with FIGS. 15-16. In the illustrated
embodiment, both drive modules 144, 146 are linear drive modules,
but any suitable drive profile will work.
[0070] Referring now to FIGS. 7-8, the substrate chuck assembly 112
comprises a servomotor 160 and a substrate chuck bearing cassette
162, each having a pulley mounted thereon and each being mounted to
the support plate 163. The pulley of the motor 160 and the pulley
of the cassette 162 are connected by a timing pulley drive belt
164. The substrate chuck bearing cassette 162 has a tubular, or
open-center, shaft 166 providing an area 168 that can contain
dispensers, sensors and other components. In some embodiments, the
area 168 is a dispensing area through which cleaning fluid can be
directed to apply fluid to a lower surface of the substrate.
Although described herein as a bearing cassette, any suitable
bearing that will work with the tubular shaft 166 can be used.
[0071] The tubular shaft 166 provides access for tubing, wiring,
mechanical components and the like 170 which may perform cleaning
of the bottom side of the substrate 114. For example, a bottom-side
fluid dispenser 171 can extend upwardly through the tubular shaft
166 into a position to be able to apply liquid to the bottom
surface of the substrate 114 (see FIG. 9B). FIG. 9B shows that the
bottom-side fluid dispenser 171 can provide unobstructed access for
fluid directed through the bottom-side fluid dispenser 171. The
dispenser 171 is shown schematically in FIG. 9B with no mounting
hardware. There are many ways that the dispenser 171 could be
mounted so that it can deliver cleaning media to the substrate
surface. For example, the dispenser 171 could be held in place by a
bracket 173 mounted on the support plate 163. This bracket could be
generally in a "J" shape, with the upstanding portion of the "J"
extending into the open center shaft and with the two upstanding
portions straddling the pulley attached to the inner race of the
bearing cassette (see FIGS. 7-8). The plurality of dispensers 108
mounted at an elevation higher than the substrate 114, meanwhile,
are able to apply liquid to the top surface of the substrate 114.
In this way, the apparatus 100 can perform simultaneous cleaning of
both sides of the substrate 114.
[0072] As shown in FIG. 9B, the substrate chuck 110 has a lower
support 172, which is a horizontally extending portion, that is
secured to an upper end of the tubular shaft 166 of the bearing
cassette 162 with a plurality of chuck mounting fasteners 174. The
bearing cassette 162 is also connected to the substrate chuck 110
in a manner that permits the chuck 110 to rotate with respect to
the plate 163. The tubular shaft 166 preferably has a four inch
diameter, or about a 102 millimeter diameter.
[0073] When the motor 160 is driven in a controlled manner, the
rotation of the motor 160 is transferred through the belt 164 to
the cassette 162 causing the cassette 162 and the substrate chuck
110 to also rotate in a controlled manner. The substrate chuck 110
also comprises a plurality of substrate support posts 176. The
posts 176 extend upwardly from an upper surface of the horizontal
portion, or lower portion, 172. The posts 176 are described in more
detail below. In the preferred embodiment, the substrate chuck 110
is fixed in the direction perpendicular to the surface of the plate
163, vertically fixed in the arrangement shown. Other substrate
chucks configured to telescope (i.e. to be movable in the direction
of the axis of rotation) are known could be implemented in this
substrate cleaning system as well.
[0074] As shown in FIG. 9B, the substrate chuck 110 supports the
substrate 114 above the bearing cassette 162. The substrate 114 is
positioned at an elevation above the bearing cassette 162 by the
plurality of substrate support posts 176. As may be seen, the
support posts are reinforced by a band 177 connecting each of the
support posts 176 about half the distance up the posts 176. The
band 177 prevents the posts 176 from flexing in operation so that
the posts 176 continue to support the substrate 114 throughout the
cleaning and the drying processes. There is an open space between
the band 177 and the base of the chuck 110 which permits liquid
beneath the substrate to escape out the side of the chuck.
[0075] By so supporting the substrate 114, a space is created
underneath the substrate 114 which may be accessed by the various
components 170. The substrate support posts 176 provide a passive
restraint of the substrate 114. The passive restraint may comprise
a notch which is located on the side of the post closest to the
axis of a rotation of the bearing cassette 162. This notch
comprises a horizontal portion and a vertical portion. The
horizontal portion provides a surface upon which the substrate 114
rests. Therefore, the horizontal portion of the support post 176
provides a passive restraint in the vertical direction against the
force of gravity. The vertical portion provides a surface upon
which the outer edge of the substrate 114 may be pressed by the
rotation of the substrate chuck 110. Therefore, the vertical
portion of the support post 176 provides a passive restraint in the
form of centripetal force in the horizontal direction. Of course
other devices could be used to hold the substrate in position, such
as a mechanism actuated by the rotation of the chuck 110. Such a
mechanism would press against the substrate to hold it in place
when the substrate is rotating, but release it when it is not.
[0076] Referring to FIG. 10, the process bowl 106 is shown with the
cleaning components removed. The process bowl 106 is mounted on
support plate 163 and has a load/unload access slot 198 to receive
a robot arm. The slot 198 is located on the front side of the bowl
106 and is at least as wide as the diameter of the substrate 114.
The height of the slot is sufficient to allow robotic loading and
unloading of the substrate 114 onto the substrate chuck 110.
Therefore, the top of the slot 198 must be at an elevation that is
higher than the top of the substrate support post 176 by at least
the thickness of the substrate 114. The bottom of the slot 198 is
at an elevation that is at least below the horizontal portion of
the notch by an amount of the thickness of the robot arm. The robot
arm preferably has a paddle configured to extend into the open
center of the chuck 110 during the process of loading or unloading
the substrate onto the chuck 110. The paddle extends beneath the
substrate 114 but above the band 177.
[0077] Also mounted to the support plate 163 are the supports 136,
138 supporting the moveable splash guard 134. The supports 136, 138
are vertically actuatable and as they are raised, the splash guard
134 correspondingly also is raised relative to the fixed elevation
of the substrate 114 when positioned on the substrate chuck 110. As
shown, the supports 136, 138 may comprise one or more hinges 139 to
facilitate the movement of the splash guard 134. Of course other
numbers of moveable supports could also be used to move the splash
guard 134.
[0078] Referring now to FIGS. 11A-11C, the supports 136, 138 are
vertically moveable so as to position the moveable splash guard 134
appropriately with respect to the slot 198 and with respect to the
substrate 114 when it is positioned on the chuck 110.
[0079] Referring to FIG. 11A, the supports 136, 138 are moveable
such that the front of the moveable splash guard 134 is disposed at
an elevation below the slot 198. This may be termed the retracted
position, or the substrate load/unload position. When the splash
guard 134 is in the retracted position, a robot arm delivering the
substrate 114 into the processing chamber can be extended through
the slot 198 until the substrate 114 is directly above the
substrate chuck 110. Then the robot arm can lower the substrate 114
onto the chuck 110. This is referred to herein as loading the
substrate onto the substrate support, or chuck. As described above,
the slot 198 is tall enough so that the robot arm can be lowered to
an elevation below the horizontal portion of the notch in the
support posts 176. At this lower position, the robot arm can be
withdrawn from the processing chamber without touching the
substrate 114. The retracted position of the splash guard 134 thus
facilitates loading and unloading using a robot arm.
[0080] Referring to FIG. 11B, the moveable splash guard 134 can
also be positioned by actuating the supports 136, 138 into a wet
processing position. In the wet processing position, the front side
of the splash guard 134 is disposed at an elevation higher than the
rear side of the splash guard 134. The elevation of the top of the
splash guard 134 is above the front side of the substrate 114 and
is just low enough near the rear side to provide access to the
substrate 114 for the cleaning probe 122. There is also just enough
clearance in this position for the liquid and vapor outlets of the
drying head 128 to be extended out over the substrate 114. In this
position, the splash guard 134 contains the processing liquids,
preventing them from escaping through the slot 198. At the rear
side of the substrate 114, a small portion of the substrate 114 may
be at or just above the elevation of the splash guard 134. This
prevents all but a very small amount of liquid from being flung
over the top of the splash guard 134. Floating seals surround the
probe 122 and drying head 128 to contain this small amount of
liquid. Also, the bottom of the splash guard 134 is at an elevation
below the bottom of the slot 198.
[0081] Finally, referring to FIG. 11C, the supports 136, 138 can be
actuated to move the moveable splash guard 134 into a dry process
position in which the drying head 128 is extended out over the top
surface of the substrate 114. In this position, the splash guard
134 is brought to a generally horizontal position, i.e. the
perpendicular distance from the substrate 114 to the plane of the
top of the splash guard 134 is a constant value. In the dry process
position, the top of the splash guard 134 is at an elevation above
the slot 198 and the bottom of the splash guard 134 is at an
elevation below the bottom of the slot 198. This prevents any
liquid which is flung off the substrate from exiting the apparatus
100 into the surrounding area. The splash guard 134 also deflects
processing liquids away from the substrate surfaces to prevent
splash-back onto the surface of the substrates.
[0082] Referring to FIG. 12, the moveable splash guard 134
comprises a cylindrical band 210 with an annular surface having a
diameter greater than the diameter of the substrate chuck 110 but
less than the diameter of the process bowl 106 (see FIG. 1).
Connected to the top portion of the cylindrical band 210 is a
frusto-conical portion 212 disposed at an angle .alpha. with
respect to the plane of the base of the splash guard 134. The inner
diameter of the conical portion 212 is greater than the outer
diameter of the substrate chuck 110. The annular surface of the
frusto-conical portion 112 that faces the substrate 114 is
preferably smooth. Other surfaces may also be effective, however,
such as the mesh-type splash guard described in connection with
FIG. 14 below.
[0083] As may be seen in FIG. 12, liquid on the surface of the
substrate 114 is projected off the substrate 114 towards the
annular surface of the conical portion 212 of the moveable splash
guard 134 by centrifugal force arising from the spinning of the
substrate 114. This liquid strikes the annular surface of the
conical portion 212 at the angle .alpha. and is deflected by the
annular surface of the conical portion 212 of the moveable splash
guard 134 in a direction that is generally downward but also
radially outward from the outer edge of the substrate 114. The
angle .alpha. is between 10 degrees and 60 degrees in one
embodiment. The angle .alpha. is between 20 degrees and 50 degrees
in another embodiment. The angle .alpha. is between 30 degrees and
40 degrees in another embodiment. The smoothness of the annular
surface of the conical portion 212 tends to preserve the droplets
rather than causing them to vaporize. As mentioned above, and
discussed in more detail in connection with FIG. 14, other splash
guard surface configurations can also prevent splash-back onto the
substrate 114.
[0084] FIG. 13 further illustrates the trajectory of the liquid
which is transported off the surface of the substrate 114 by the
centrifugal force exerted on the liquid on the surface of the
spinning substrate 114. The trajectory of the transported liquid is
generally in the direction of the rotation of the substrate 114. As
the liquid moves off the substrate it travels toward the annular
surface of the conical portion 212, strikes the annular surface and
is deflected at an angle away from its original path between the
substrate 114 and the annular surface. The liquid is deflected in
such a manner as to prevent the liquid from splashing back onto the
substrate 114. Splash-back of liquid can be prevented by
positioning the annular surface at an angle, as described above, so
that the liquid is deflected downward relative to the elevation of
the surface of the substrate and outward radially from the center
of the chuck 110. As mentioned above, the drying process works by
displacing the cleaning liquids on the substrate surface with
surface tension reducing liquid. The moveable splash guard 134 is
used in conjunction with the drying assembly 120 to assure little
or no drying through evaporation from the substrate surface of
splash-back of cleaning liquid occurs.
[0085] Referring now to FIG. 14, a mesh-type splash guard 230 is
shown. The mesh-type splash guard 230 comprises a frame 232 and a
mesh portion 234. The mesh portion 234 preferably comprises a
plurality of strands arranged in a crossing fashion (e.g.
perpendicularly crossing) to form a grid of rectangular openings.
More generally, two sets of strands may form any quadrilateral
shape. Also, more than two sets of strands may be used to form the
mesh with openings of any polygon shape. In one variation, the mesh
has about a 1 mm aperture with about a 44 percent open area. The
mesh portion 234 may be affixed to the frame 232 or the frame and
mesh may be unitary. Although shown as a cylinder, the mesh-type
splash guard 230 may have a variety of shapes, and may, for
example, be formed as a frusto-conical portion, like the splash
guard 134.
[0086] Another variation comprises a splash guard having at least
two mesh sections. In this arrangement, a second mesh section is
positioned generally concentrically around a first mesh section.
Generally, the first mesh section will have apertures and open area
equal to or larger than the apertures and open areas of the second
mesh. The second mesh can have about a 1 mm aperture with about a
44 percent open area. In another variation, the second mesh can
have about a 0.3 mm aperture with a 36 percent open area. In still
another variation, the first mesh section can have about a 1 mm
aperture with about a 44 percent open area and the second mesh can
have about a 0.3 mm aperture with about a 36 percent open area. Yet
another variation involves using a mesh portion similar to mesh
portion 234 in conjunction with an annular splash guard similar to
the guard 134.
[0087] As with the splash guard 134, the splash guard 230 may be
attached to supports 136 and 138 that are vertically actuatable.
Together with the hinges 139, the supports 136, 138 permit the
mesh-type splash guard 230 to be moved as the splash guard 134 is
moved, as shown in FIGS. 11A-11C. Like the conical portion 212, the
mesh portion 234 of the mesh-type splash guard 230 intercepts the
liquid being spun off of an upper surface of the substrate 114 in a
manner that prevents the liquid from splashing back onto the upper
surface of the substrate 114.
[0088] Referring now to FIGS. 6, 15, and 16, the cleaning and
drying apparatus 100 comprises a drying assembly drive module 146.
In the preferred embodiment, the drive module 146 comprises a
servomotor 250, a linear bearing 252, a lead-ballscrew 254, and a
proximity sensor 256 for sensing a limit position and a home
position. The drying assembly 120, which includes the drying head
128 and the substrate drying assembly support arm 130, is mounted
onto the drive module 146 with a bracket 258.
[0089] FIG. 16 shows all the components of the drive module 146
shown in FIG. 15, and further shows the drive mechanism housing 180
in phantom revealing the timing belt and pulley drive assembly 182.
Although the cleaning assembly drive module 144 is not shown in
detail, its construction is similar to the construction of the
drive module 146, except the drying assembly 120 is replaced with
the cleaning assembly 118.
[0090] The drive modules 144, 146 are driven by a controller 147
which positions the probe 122 or the drying head 128 radially with
respect to the substrate 114. For example, the probe 122 is
inserted or retracted radially from the processing chamber of the
process bowl 106 by the drive module 144. The drive module 144 is
connected to the cleaning assembly 118 and moves it radially with
respect to the substrate 114 such that the end of the probe 122
extends toward or is retracted away from the center of the
substrate 114. The drive module 144 also can retract the probe 122
so that it is outside of the outer diameter of the substrate 114.
Similarly, the drive module 146 can extend the drying head 128 to a
position at an elevation above the substrate 114 but within its
radius and can also retract the cleaning head 128.
[0091] The controller 147 which actuates the drive modules 144, 146
can be used to implement various control strategies to maximize
performance of the cleaning apparatus 100. Different control
strategies may be selected depending upon many factors, for
example, the size of the substrate, the cleaning solution used, the
sensitivity of the structures being constructed on the surface of
the substrate, and the degree of cleanliness required, among
others. These control strategies can be illustrated graphically,
for example on a two-dimensional graph.
[0092] As shown in FIG. 17, the position of the probe 122 with
respect to the substrate 114 can be illustrated over time. One way
to illustrate this is to plot the position of the probe with
respect to the edge or center of the substrate 114 on the y-axis
and time on the x-axis. The position of the edge of the substrate
114 and the center of the substrate 114 are shown on the y-axis as
dashed lines. The dashed line closer to the x-axis represents the
edge of the substrate 114, while the dash line furthest from the
x-axis represents the center of the substrate 114. The solid line
in FIG. 17 represents the position of the probe 122 over time with
respect to the substrate 114. The servomotor 250 extends the probe
122 in a generally radial direction at a constant linear velocity
with respect to the bearing 252 until the probe tip is located at
or just beyond the center of the substrate 114. Then, in one
embodiment, the controller 147 stops the servomotor 250, making the
linear velocity of probe 122 zero during the cleaning operation. In
another embodiment, as discussed above in connection with FIGS.
2-3, liquid can be applied to the probe 122 to load the probe 122
while the probe 122 is being extended from the dispenser 109. In
that case, the cleaning can take place while the probe 122 is being
extended over the substrate 114. The probe 122 can also be loaded
while it is stationary over the substrate 114 to lessen damage to
structures on the substrate 114, to tune the probe 122, or for
other reasons. At completion of the cleaning, the probe 122 is
retracted at a constant linear velocity until it reaches the home
position, which is radially farther from the center of the bearing
cassette 162 than is the outer edge, or periphery, of the substrate
114. In another variation, megasonic energy can be applied to the
probe 122 while it is being retracted. In that case, it may be
necessary to load the probe 122 in order to apply the appropriate
amount of megasonic energy to the surface of the substrate 114
while retracting the probe 122.
[0093] Another example control strategy is illustrated in FIG. 18,
again in x-y coordinates, showing time and position respectively.
The servomotor 250 extends the probe 122 in a generally radial
direction at a constant velocity until the end of the probe 122
extends at or beyond the center of the substrate 114. Then, the
controller 147 directs the servomotor 250 to stop, so the velocity
of the probe is zero and the position of the probe 122 is held
constant during the cleaning operation. Next, the controller 147
directs the servomotor 250 to retract the probe 122 at a varying
velocity. That is, the linear velocity of the probe 122 with
respect to the bearing 252 is greatest at the beginning of the
retraction and the linear velocity of retraction is reduced
continuously over the distance of travel of the probe 122 towards
the edge of the substrate.
[0094] Referring to FIG. 19, a control strategy for the drying
assembly drive module 146 is illustrated. In this strategy the
controller 147 directs the servomotor to extend the drying head 128
at a constant velocity from the edge of the substrate 114 to just
beyond the center of the substrate 114. Then the controller 147
directs the servomotor 250 to stop, bringing the velocity of the
drying head 128 at zero and holding its position constant for a
period of time. Next, the controller 147 directs the servomotor 250
to retract the drying head 128 at a varying velocity, with the
velocity of retraction being greatest at the beginning and with the
velocity decreasing while the drying head 128 is moving toward the
edge of the substrate 114. Next, the controller 147 directs the
servomotor 250 to stop retracting the drying head 128 near the edge
of the substrate 114, which brings the velocity of the drying head
128 to zero and holds its position constant for a period of time.
Finally, the controller 147 directs the servomotor 250 to retract
the drying head 128 at a constant velocity to return the drying
head 128 to the home position.
[0095] The cleaning and drying apparatus 100 described above can be
controlled to provide a satisfactory cleaning and drying process as
illustrated by one preferred embodiment in FIG. 20. The process
begins at a start block 300. Then, at a process block 302, the
drive module 144 positions the probe 122 closely spaced above an
upper surface of the substrate 114, which is positioned in and
rotating with the chuck 110. Next at a process block 304, fluid is
applied to the substrate 114 to create a meniscus between the probe
122 and the substrate 114. Then, in a process block 306 megasonic
energy is applied to the probe 122 to cause it to propagate the
megasonic energy through the meniscus to the substrate 114. The
megasonic energy applied to the substrate 114 loosens particles on
the substrate 114. The megasonic energy is strongest in the region
of the probe 122. Therefore, it is preferred that the substrate 114
rotate beneath the probe at a first rate so that the entire upper
surface of the substrate 114 is exposed to the megasonic energy. In
one variation, the process steps 304 and 306 may be combined. In
that case, megasonic energy is applied to the probe 122 as the
probe is being extended over the substrate 114. This variation may
further include applying liquid to the probe 122 through the
dispenser 109 while the megasonic energy is being applied to the
probe and while the probe is being extended over the substrate 114.
Next in a process block 308 the probe 122 is retracted at or near
the completion of a cleaning operation. In yet another variation,
the process blocks 304, 306, and 308 could all be combined so that
megasonic energy is applied to the surface of the substrate 114
through the probe 122 while the probe 122 is being extended, while
it is stationary over the substrate surface, and while it is being
retracted. In each of these stages, it may be desired to apply
loading liquid to the probe 122 through the dispenser 109 to reduce
the power applied to the surface of the substrate 114, to tune the
probe 122, or for other reasons. Then, in a process block 310, the
substrate 114 is rinsed with a suitable liquid. One preferred
rinsing liquid is de-ionized water. In another variation, the
process block 310 could include a chemical treatment, such as a
treatment with hydrofluoric acid.
[0096] Then, in a process block 312 the substrate drying assembly
support arm 130 is moved into position closely spaced above the
substrate 114. The process block 312 is preferably at least
partially performed concurrently with the process block 308.
[0097] As described above, the drying assembly 120 includes an
outlet for applying liquid to the upper surface of the substrate
and also includes an outlet for applying a drying vapor to the
upper surface of the substrate. Next, in a process block 314, the
substrate drying assembly support arm 130 is positioned so that the
liquid applying outlet of the drying assembly 120 is located
approximately over the center of the substrate 114. Any of the
process blocks 308-320 could include increasing the rate of
rotation of the substrate 114 to a second rate. The second rate of
rotation of the substrate 114 is preferably much greater than the
first rate of rotation of the substrate 114. At higher rates of
rotation, processing liquid is flung off the substrate surfaces at
a higher velocity. This increases the likelihood of splash-back. As
mentioned above in connection with FIGS. 11B and 11C, the splash
guard 134 is configured to minimize this. In the position shown in
FIG. 11B, most of the periphery of the substrate 114 is below the
upper edge of the splash guard 134. As shown in FIG. 11C, all of
the periphery of the substrate 114 is below the splash guard 134.
Thus, there is minimal area not protected from splash-back by the
splash guard 134.
[0098] Then, in a process block 316, liquid is applied to the
substrate 114 through the liquid applying outlet of the drying head
128. In one advantageous alternative, the process block 316 is
implemented at least partially concurrently with the process block
314. In this way, the liquid is applied to the substrate 114
through the liquid applying outlet of the drying head 128 while the
substrate drying assembly support arm 130 is moved to the center of
the substrate 114. In a process block 318, the substrate drying
assembly support arm 130 is retracted to a position where the
drying outlet of the drying head 128 is positioned over the center
of the substrate 114. In a process block 320, the tensioactive
vapor is applied to the substrate 114 as the substrate 114 rotates.
The vapor applied at the process block 320 dries the center of the
substrate 114 due to the rotation and by the action of the vapor on
the liquid on the surface of the substrate 114. In a process block
322 the substrate drying assembly support arm 130 is retracted
radially outwardly at a controlled rate to the periphery of the
substrate 114. As the substrate drying assembly support arm 130 is
being withdrawn, liquid is applied to the substrate 114 through the
liquid outlet of the drying head 128. The control of the retraction
is discussed in more detail below. In the process block 322 the
drying head 128 applies tensioactive vapor to the substrate 114
through the vapor applying outlet following the application of
liquid. Then in a process block 324, when the drying head 128
approaches the periphery of the substrate, the application of
liquid to the upper surface of the substrate 114 is stopped. In a
process block 326, the retraction of the substrate drying assembly
support arm 130 is stopped near the periphery of the substrate 114.
In the process step 326 the rotational speed of the substrate 114
is also greatly increased. This tends to dry a lower surface of the
substrate 114 by centrifugal action. Then, in a process block 328,
the application of drying vapor to the substrate 114 is stopped
before the drying head 128 is retracted beyond the outer periphery
of the substrate 114. In an end block 330, the drying head 128 is
retracted to the home position, the rotation of the substrate 114
is stopped, and the process is completed.
[0099] As mentioned above, one important consideration applied to
the single wafer cleaning apparatus is through-put. Consequently,
the process embodied in process steps 300-330 can be optimized to
minimize cleaning, rinsing, and drying time. To this end, it will
be appreciated that some of the above process blocks could be
combined with the process still implementing the invention. For
example, in one variation of the above process, process blocks 308,
310, and 312 are carried out at least partially concurrently. In
another variation of the process described above, process blocks
318 and 320 could be carried out partially concurrently. Also,
although the lower-numbered process blocks noted above generally
begin before the higher-numbered blocks, many of the blocks are
executed at least partially concurrently.
[0100] The process described above can be incorporated into a wide
variety of cleaning and drying recipes. For example, one drying
recipe for an 8 inch, or a 200 millimeter, substrate begins after
the probe 122 is retracted in the process block 308. The process
block 310 commences by rotating the substrate at the second rate,
e.g. 300 RPM (the first rate of rotation being that required by the
cleaning assembly 118). This second rate is maintained for 29
seconds. In the process block 310 the substrate 114 is rinsed for 5
seconds. The process block 310 also can include a hydrofluoric acid
exposure.
[0101] The process block 312, which moves the substrate drying
assembly support arm 130 toward a location over the center of the
substrate 114, begins 4 seconds before the end of process block
310. In the process block 314, the substrate drying assembly
support arm 130 is positioned so that the liquid applying outlet of
the drying head 128 is located approximately over the center of the
substrate 114. At the process block 316, liquid is applied to the
substrate 114 through the liquid applying outlet of the drying head
128. This continues until process block 324. At the process block
318, the substrate drying assembly support arm 130 is retracted.
When process block 318 is completed the drying outlet of the drying
head 128 is positioned over the center of the substrate 114. At the
process block 320, the tensioactive vapor is applied to the
substrate 114. Next, at the process block 322, the substrate drying
assembly support arm 130 is retracted radially outwardly while
liquid and vapor are applied to the substrate 114 through the
liquid and vapor outlets of the drying head 128 respectively. Next
at the process block 324 the application of liquid to the substrate
114 is stopped. The retraction of the drying head 128 is stopped at
the process block 326. Still at the process block 326 the
rotational speed of the substrate 114 is greatly increased so as to
dry a lower surface of the substrate 114. This increased speed is
preferably 1000 revolutions per minute (RPM) or higher and is more
preferably 1800 RPM. Finally, at the process block 328 the
application of vapor to the substrate 114 is stopped and the drying
head 128 is retracted beyond the outer periphery of the substrate
114. As mentioned, the above recipe is for an 8 inch, or a 200
millimeter, substrate. It will be recognized that the times may
vary for different applications, including different substrate
sizes.
[0102] The cleaning apparatus disclosed herein also exploits a
relationship between the rate of rotation of the substrate 114 and
the rate at which the drive module 146 retracts the drying head
128. Generally, the faster the rotation, the faster the retraction
can be. In some embodiments, it is desired to provide adequate
drying in the shortest time. FIG. 21 provides one example
relationship between substrate rotation rate and drying assembly
retraction rate where it is desired to use a single, constant
retraction rate. As may be seen in connection with FIGS. 22A-22B,
higher retraction rates for the same rotation rate can be achieved
under some conditions.
[0103] Referring now to FIG. 21, one example relationship between
the rotation rate and the retraction rate is illustrated as a
two-dimensional processing window. The x-axis of the processing
window represents a range of rates at which the substrate drying
assembly support arm 130 and the drying head 128 of the drying
assembly 120 can be retracted. The y-axis represents the range of
revolutions per minute (RPM) at which the chuck 110 can rotate the
substrate 114. In the example relationship shown in FIG. 21, the
substrate 114 can be rotated during the substrate top surface
drying operation in a range between about 200 RPM and about 1,000
RPM while the substrate drying assembly support arm 130 can be
retracted in a range between about 4 mm per second and about 9 mm
per second. In another embodiment, the substrate 114 can be rotated
during the substrate top surface drying operation in a range
between about 50 rpm and about 1000 rpm, while the substrate drying
assembly support arm 130 can be retracted in a range between about
1 mm per second and about 20 mm per second. It will also be
understood that higher substrate rotational rates are possible and
that, as shown in FIG. 21, such higher rotation rates will enable
drying assembly retraction at rates higher than those shown in FIG.
21.
[0104] Two advantageous process windows governing the rate of
retraction of the substrate drying assembly support arm 130 and the
rate of rotation of the substrate 114 are further illustrated in
FIG. 21. A line 402 represents a blanket substrate process window,
which is a preferred relationship between the rate of retraction of
the substrate drying assembly support arm 130 and the rate of
rotation of a blanket substrate. A blanket substrate is one that
has a uniform top surface. A line 404 represents a patterned
substrate process window, which is a preferred relationship between
rate of retraction of the drying assembly and the rate of rotation
of a patterned substrate. A patterned substrate is one that has one
or more features created on the top surface. The preferred rate of
retraction of the substrate drying assembly support arm 130 for a
blanket substrate is about 5 millimeters per second when the rate
of rotation of the substrate 114 is about 300 RPM. The preferred
rate of retraction of the substrate drying assembly support arm 130
for a patterned substrate is about 4 millimeters per second when
the rate of rotation of the substrate 114 is about 300 RPM. As can
be seen, the preferred rate of retraction can be increased by about
0.5 mm per second for each 100 increase in the RPM of substrate
rotation. For blanket substrates that are rotated faster than 900
RPM, the preferred rate of retraction of the substrate drying
assembly support arm 130 is increased as the rate at which the
substrate 114 is rotated is increased about 1.0 mm per second for
each 100 increase in the RPM of substrate rotation.
[0105] The blanket and patterned process windows shown in FIG. 21
also illustrate other alternative rates of retraction that perform
a satisfactory dry for a given substrate rotational speed. For
example, for blanket substrates the rate of retraction of the
substrate drying assembly support arm 130 of the drying assembly
120 may be lower than the preferred rate while still performing a
satisfactory dry. These lower rates are the retraction rates that
are to the left of the line 402. Also, for patterned substrates,
substrate drying assembly support arm 130 of the drying assembly
120 may be retracted at rates that are lower than the preferred
rate while still performing a satisfactory dry. These lower
retraction rates for patterned substrates are to the left of the
line 404. Also, the rotation rate for a given retraction rate may
be higher than (i.e. above on the graph) the preferred rate
illustrated by the lines 402, 404.
[0106] It has been found that some areas or zones in the substrate
dry faster than others areas or zones. FIGS. 22A-22B illustrate
that this relationship that can be exploited in order to manage
cleaning efficiency and cleaning times (and, therefore,
through-put). In other words, the process windows shown in FIG. 21
can be applied to the slowest drying zone. Other process windows
reflecting faster drying assembly retraction rates can be
implemented in the faster drying zones, as described below.
[0107] Referring now to FIGS. 22A-22B, the drying head 128 can be
retracted at different rates as it is moved from the center of the
substrate 114 to the edge of the substrate 114. In one embodiment
illustrated in FIG. 22A, and preferred for blanket substrates, the
substrate 114 is divided into a zone 502 near the center of the
substrate 114 and a zone 504 near the periphery of the substrate
114. The dashed arrow illustrates the retraction of the substrate
drying assembly support arm 130. The retraction rate near the
center of the substrate 114 in the zone 502 is preferably faster
than the retraction rate near the periphery of the substrate 114 in
the zone 504 because the periphery of the substrate may dry more
slowly.
[0108] Alternately for patterned substrates, as illustrated in FIG.
22B, the substrate 114 can be divided into a zone 512 near the
center of the substrate, a zone 514 near the periphery of the
substrate 114, and a zone 516 between the zones 512, 514. In one
embodiment, the substrate drying assembly support arm 130 can be
retracted while in the zone 516 at a rate faster than that in zone
512 near the center of the substrate 114 (the substrate-center
retraction rate) and faster than that in zone 514 near the
periphery of the substrate 114 (the substrate-periphery retraction
rate). That is, the center of the substrate 114 may dry more slowly
than the adjacent zone, but the center of the substrate 114 may dry
faster than the periphery of the substrate 114.
[0109] It will be appreciated by one of ordinary skill in the art
that the invention can also be embodied in control strategies that
employ other numbers of zones and other locations on the substrate
114. It will also be appreciated that the retraction rate of the
substrate drying assembly support arm 130 could be zero mm per
second, i.e. the arm could be held still, for a period of time in
one or more of the zones.
[0110] Referring now to FIGS. 6, 9A, 9B, and 23-25, the apparatus
100 described herein is uniquely arranged to be stackable and to be
incorporated into a substrate processing system 700. The substrate
processing system 700 comprises a first substrate cleaner 702
comprising a forward portion 704. The forward portion 704 includes
a rotatable substrate support, or chuck 110, a dispenser 108 for
applying fluid onto a substrate 114, and a probe 122 to be
positioned closely spaced above the substrate to enable a meniscus
of the liquid to be formed between the probe 122 and the substrate
114. The probe 122 is configured to loosen particles on the
substrate in response to megasonic energy being applied to the
probe 122.
[0111] The cleaner 702 also includes a rear portion 706 that is
vertically thicker than the forward portion 704. The rear portion
706 includes a device for rotating the support 110, such as the
servomotor 160, and one or more liquid or gas supply lines for
conducting fluid to the dispenser 108. The rear portion 706 also
includes a drive module 144 for moving the probe, as well as
connections for applying megasonic energy to the probe.
[0112] The system 700 includes a second substrate cleaner 722. Like
the substrate cleaner 702, the cleaner 722 includes a forward
portion 724 and a rear portion 726 that is vertically thicker than
the forward portion 724. In the system 700, the second cleaner 722
can be stacked below the first cleaner 702 with the forward
portions being vertically aligned and the rear portions being
vertically aligned. In this position, a space 730 is formed between
the forward portions 704, 724 to permit ample gas flow into the
space 730 between the forward portions of the cleaners. Stacking
the first substrate cleaner 702 and the second substrate cleaner
722 reduces the cleanroom floor space which must be dedicated to
cleaning and drying.
[0113] The vertical thickness of the bowl area is minimized by
several related techniques. Utilizing the vertically fixed support
chuck facilitates this by having the substrate handling robot
provide the necessary vertical movement when transporting a
substrate. A mechanism for vertically moving the chuck requires
greater vertical space, which interferes with the air-flow to the
substrate area. The slot 198 in the process bowl 106 enables use of
the robot without increasing the space requirements because space
beneath the substrate is desirable for applying liquid to the
substrate lower surface. The moveable splash guard 134 permits the
use of the slot 198 for substrate transfer.
[0114] As shown in FIGS. 24-25, the first and second substrate
cleaners 702, 722 can be mounted into a stackable cleaner mounting
system 800. The system 800 comprises a frame 802 defining a cleaner
housing portion 806, and a plumbing and pneumatic support cabinet
housing portion 808.
[0115] The cleaner housing portion 806 provides a space 820 where
the cleaners 702, 722 are mounted. Each of the cleaners 702, 722
advantageously can be mounted on at least one drawer slide 822
comprising a cleaner fixture 824 mounted to the cleaner 722 or the
cleaner 702, a translating portion 826, and a frame fixture 828
mounted to the frame 802. The fixtures 824, 828 can be configured
to slideably interface with the translating portion 826. The
fixtures 824, 828 preferably also are configured to support the
weight of the cleaner 722 when it is within the housing portion 806
and when it is pulled out, as shown in FIGS. 24-25. Although shown
retracted within the housing portion 806, the cleaner 702 also can
be mounted to the frame 802 with a drawer slide 822. The cleaners
702, 722 are thus fixed vertically, but configured to translate
horizontally so that they can be pulled out for inspection,
testing, service, and maintenance. In one variation, the cleaners
702, 722 also could be mounted so as to be fixed vertically and
horizontally, i.e. without the drawer slide 822.
[0116] The plumbing and pneumatic support cabinet housing portion
808 provides a space 840 in which a plumbing and pneumatic support
cabinet 841 can be positioned. The cabinet 841 can include, for
example, various liquid and gas hook-up lines, control lines, and
the like. At least one external hook-up panel 842 can be provided
to simplify the connection, maintenance, and exchange of the
various fluid lines. Also, a control panel 844 can be provided to
enhance the connection of a controller and one or more gauges for
monitoring the performance of the cleaners 702, 722.
[0117] The pneumatic support cabinet 841 may include a shielding
portion 860, one or more facility pass-through panels 862, and a
pneumatic control signal panel 864. The shielding portion 860
shields the cleaners 702, 722 from the various components
positioned within the cabinet 841 and also protects the components
within the cabinet. The facility pass-through panels 862 provide
one ore more convenient hook-up ports 866 for connecting the
various fluid supply lines to the cleaners 702, 722. The pneumatic
control signal panel 864 provides convenient pneumatic control
hook-ups for the cleaners 702, 722.
[0118] It should be recognized that various modifications may be
made to the embodiments illustrated without departing from the
scope of the invention, and all such changes are intended to fall
within the scope of the invention, as defined by the attended
claims.
* * * * *