U.S. patent application number 11/405135 was filed with the patent office on 2006-08-17 for semiconductor substrate cleaning system.
Invention is credited to Brian J. Brown, Anwar Husain, Fred C. Redeker.
Application Number | 20060180177 11/405135 |
Document ID | / |
Family ID | 26829161 |
Filed Date | 2006-08-17 |
United States Patent
Application |
20060180177 |
Kind Code |
A1 |
Brown; Brian J. ; et
al. |
August 17, 2006 |
Semiconductor substrate cleaning system
Abstract
A modular semiconductor substrate cleaning system is provided
that processes vertically oriented semiconductor substrates. The
system features a plurality of cleaning modules that may include a
megasonic tank-type cleaner followed by a scrubber. An input module
may receive a horizontally oriented substrate and rotate the
substrate to a vertical orientation, and an output module may
receive a vertically oriented substrate and rotate the substrate to
a horizontal orientation. Each of the modules (input, cleaning and
output) has a substrate support and may be positioned such that the
substrate supports of adjacent modules are equally spaced. The
modules are coupled by an overhead transfer mechanism having a
plurality of substrate handlers spaced the same distance (X) as the
substrate supports of the modules therebelow. The transfer
mechanism indexes forward and backward the distance X to
simultaneously transport semiconductor substrates through the
cleaning system, lifting and lowering substrates from the desired
modules wafer rotation/orientation sensors, an input module cart
for transporting wafers between a substrate handler of a previous
tool (such as a semiconductor substrate polisher) and a substrate
handler of the cleaning system are also included.
Inventors: |
Brown; Brian J.; (Palo Alto,
CA) ; Husain; Anwar; (Pleasanton, CA) ;
Redeker; Fred C.; (Fremont, CA) |
Correspondence
Address: |
DUGAN & DUGAN, PC
55 SOUTH BROADWAY
TARRYTOWN
NY
10591
US
|
Family ID: |
26829161 |
Appl. No.: |
11/405135 |
Filed: |
April 17, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10425260 |
Apr 29, 2003 |
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11405135 |
Apr 17, 2006 |
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09558815 |
Apr 26, 2000 |
6575177 |
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10425260 |
Apr 29, 2003 |
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60131124 |
Apr 27, 1999 |
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60143230 |
Jul 10, 1999 |
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Current U.S.
Class: |
134/2 ; 134/18;
134/25.1; 257/E21.228 |
Current CPC
Class: |
H01L 21/02052 20130101;
B08B 3/08 20130101; H01L 21/67028 20130101; H01L 21/67051 20130101;
H01L 21/67751 20130101; H01L 21/67046 20130101; H01L 21/67057
20130101; B08B 3/12 20130101; H01L 21/68 20130101; Y10S 134/902
20130101; H01L 21/67757 20130101; B08B 1/04 20130101 |
Class at
Publication: |
134/002 ;
134/018; 134/025.1 |
International
Class: |
C23G 1/00 20060101
C23G001/00; B08B 9/20 20060101 B08B009/20; B08B 7/04 20060101
B08B007/04 |
Claims
1. A method of automatically cleaning a semiconductor substrate
within a semiconductor substrate cleaning system comprising:
cleaning a first semiconductor substrate within a sonic cleaning
tank while cleaning a second semiconductor substrate within a
scrubber; automatically transferring the first semiconductor
substrate to the scrubber via an overhead transfer mechanism; and
automatically transferring the second semiconductor substrate from
the scrubber via the overhead transfer mechanism.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/425,260 filed Apr. 29, 2003 which is a
division of U.S. patent application Ser. No. 09/558,815, filed Apr.
26, 2000, which claims priority from U.S. Provisional Patent
Application Ser. Nos. 60/131,124 filed Apr. 27, 1999 and 60/143,230
filed Jul. 10, 1999. All of these patent applications are
incorporated by reference herein in their entirety.
BACKGROUND OF THE INVENTION
[0002] Currently available semiconductor substrate cleaning
equipment suffers from high cost per unit substrate cleaned,
unreliable removal of large flat particles, and of particles
located along the beveled edge of a semiconductor substrate, lack
of scalability and inability to easily adapt to various processing
sequences, or to changes (e.g., increases) in semiconductor
substrate size. Among the many factors that contribute to substrate
cleaning costs, the capital cost of substrate handlers which move
semiconductor substrates between various locations presents a
significant expense. Another significant expense arises because
semiconductor substrate cleaning processes are performed within a
clean room environment. The larger the area occupied by the
cleaning system (i.e., the larger the footprint) the more expensive
the cleaning system is to operate, due to the high cost of clean
room area.
[0003] Unreliable cleaning, however, increases cleaning costs more
than any other factor. As semiconductor substrates increase in
size, failures become more expensive, and as devices formed on
semiconductor substrates decrease in size, particles are more
likely to cause failures.
[0004] Accordingly, improvements are needed in the field of
semiconductor substrate cleaning.
SUMMARY OF THE INVENTION
[0005] An inventive semiconductor substrate cleaning system
comprises a plurality of cleaning modules, each module has a
substrate support for supporting a vertically oriented
semiconductor substrate during a cleaning process, and each module
is positioned such that the substrate supports thereof are spaced a
fixed distance X. An input module positioned adjacent a first end
module of the plurality of cleaning modules has a substrate support
positioned a distance X from the substrate support of the first end
module, and an output module positioned adjacent a second end
module of the plurality of cleaning modules has a substrate support
positioned the distance X from the substrate support of the second
end module. A semiconductor substrate transfer mechanism having a
plurality of substrate handlers spaced the distance X is movably
coupled above the plurality of cleaning modules and above the input
and output modules so as to move forward and backward the distance
X, thereby simultaneously carrying semiconductor substrates between
adjacent ones of the input module, the cleaning modules and the
output module.
[0006] For cases where the substrates are not loaded vertically
into the input module and/or are not unloaded vertically from the
output module, the input and/or output modules may respectively
include a mechanism for receiving a semiconductor substrate in a
horizontal orientation and for rotating the semiconductor substrate
to a vertical orientation and a mechanism for receiving a
semiconductor substrate in a vertical orientation and for rotating
the semiconductor substrate to a horizontal orientation. Likewise,
to facilitate wafer handling, the input module may orient the
substrate to place the substrate's flat in a known position (i.e.,
flat finding) such that the wafer handler will not contact the
flat. In steady state operation, semiconductor substrates may be
loaded to and unloaded from the system, are appropriately oriented
horizontally or vertically and/or have their flats appropriately
positioned while other substrates are being cleaned. System
productivity therefore may be enhanced as the system need not idle
during the time required for substrate load/unload and orient
operations.
[0007] After semiconductor substrates are loaded to and unloaded
from the system via the input module and the output module, the
overhead transfer mechanism lowers the wafer handlers. In one
aspect the wafer handlers are simultaneously lowered into the input
module and the various cleaning modules to pick up or "grip"
semiconductor substrates contained therein. Thereafter, by simply
raising, indexing forward the distance X and lowering, the transfer
mechanism simultaneously transfers a plurality of single substrate
batches from one module to the next. The transfer mechanism ungrips
the substrates, raises and returns to the home position while
substrates are loaded/unloaded and oriented in the input and output
modules. This process repeats until each substrate receives the
desired processing and is unloaded. In this aspect, the simplicity
of the simultaneous substrate transfer mechanism provides accurate
yet cost effective substrate transfer.
[0008] The entirely vertical orientation of the cleaning modules
requires minimal footprint, and enables the inventive cleaning
system to be easily scaled. To accommodate changes in substrate
size the substrate supports and wafer handlers may be adjustable.
Thus, few alterations are required for change-over between cleaning
substrates of differing size.
[0009] Other inventive aspects of the cleaning system comprise, in
one aspect the use of a megasonic tank cleaner, followed by a
scrubber, and in another aspect the design of a cleaning system
which does not employ a scrubber.
[0010] Further features and advantages of the present invention
will become more fully apparent from the following detailed
description of the preferred embodiments, the appended claims and
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIGS. 1A-F are schematic side elevational views of an
inventive cleaning system;
[0012] FIG. 2 is a timing diagram useful in describing the
operation of the inventive cleaning system of FIGS. 1A-G;
[0013] FIGS. 3A-C are side perspective views of an inventive
interface module;
[0014] FIG. 4 is a perspective view showing the inventive interface
module of FIGS. 3A-C coupled between an existing wafer handler and
a cleaning module;
[0015] FIG. 5A is a side elevational view of a roller employed
within the inventive interface module of FIGS. 3A-C;
[0016] FIGS. 5B-C are front plan views of the cart employed within
the interface module of FIGS. 3A-C, useful in describing wafer
orientation;
[0017] FIGS. 6A-B are front plan views of the cart employed within
the interface module of FIGS. 3A-C, useful in describing an
apparatus generally useful for wafer orientation and rotation
monitoring;
[0018] FIGS. 7A-C are a side view and two front views,
respectively, of a through-beam sensor for orienting a wafer;
[0019] FIG. 8 is a schematic front elevational view of a substrate
support that is particularly advantageous for rotating flatted
substrates;
[0020] FIGS. 9A and 9B are a front elevational view of a first
embodiment of a first aspect of an inventive Marangoni drying
module 81a showing the exterior thereof, respectively showing a
substrate receiving position and a substrate guiding position as
described below;
[0021] FIG. 9C is a front sectional view of the Marangoni drying
module of FIG. 1B showing the interior thereof;
[0022] FIGS. 9D-F are sequential side sectional views of the
Marangoni drying module of FIGS. 9A, 9B, and 9C, useful in
describing the operation thereof;
[0023] FIG. 10A is a front elevational view of a second embodiment
of a Marangoni drying module; and
[0024] FIGS. 10B-D are sequential side sectional views of the
Marangoni drying module of FIG. 10A, useful in describing increased
throughput thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] FIGS. 1A-F are schematic side elevational views of an aspect
of an inventive cleaning system 11 having an input module and an
output module that rotate a substrate between horizontal and
vertical positions. The inventive cleaning system 11 comprises a
load module 13, a plurality of cleaning modules configured to
support a semiconductor substrate in a vertical orientation,
specifically a megasonic cleaner 15, a first scrubber 17, a second
scrubber 19, and a spin-rinse-dryer 21; and an unload module 23.
The megasonic cleaner 15 may be configured as described in U.S.
patent application Ser. No. 09/191,057, filed Nov. 11, 1998 (AMAT
No. 2909/CMP/RKK). The first scrubber 17 and the second scrubber 19
may be configured as described in U.S. patent application Ser. No.
09/113,447, filed Jul. 10, 1998 (AMAT No. 2401/CMP/RKK). The
spin-rinse-dryer 21 may be configured as described in U.S. patent
application Ser. No. 09/544,660, filed Apr. 6, 2000 (AMAT No.
3437/CMP/RKK) and the substrate transfer mechanism described below
may be configured as described in U.S. patent application Ser. No.
09/300,562, filed Apr. 27, 1999 (AMAT No. 3375/CMP/RKK). The entire
disclosure of each of the above identified applications is
incorporated herein by this reference. It will be apparent that the
apparatuses disclosed in the applications incorporated above are
merely exemplary and other apparatuses may also be employed.
[0026] Each of the modules 13-23 has a substrate support 25a-f,
respectively, for supporting a semiconductor substrate in a
vertical orientation. It will be understood that the substrate
supports 25b-e may be configured like the substrate supports
described in the previously incorporated U.S. Patent Applications.
The exemplary load module 13 is configured to receive a
horizontally oriented semiconductor substrate and to rotate the
semiconductor substrate to a vertical orientation. Similarly, the
exemplary unload module 23 is configured to receive a vertically
oriented semiconductor substrate and to rotate the semiconductor
substrate to a horizontal orientation. To perform such substrate
reorientation the substrate supports 25a, 25f, of the load module
13 and the unload module 23 are preferably operatively coupled to a
rotation mechanism 27a, 27b, respectively, such as a motorized
hinge.
[0027] Each of the modules may include an alignment and latching
mechanism 29a-e for securing to adjacent modules so as to hold the
modules in a predetermined position relative to each other. When in
this predetermined position the substrate supports 25a-f may be
equally spaced by a distance X (FIG. 1A). To facilitate this equal
spacing, the cleaning modules 15-21 each have a length which is
less than a distance X. Accordingly, the cleaning system 11 may be
easily reconfigured to perform a number of different cleaning
sequences. By unlatching the latching mechanisms 29a-f a module may
be easily removed, replaced or reconfigured (i.e., the modules are
"removably coupled").
[0028] The latching mechanisms 29a-e are adjustable to allow a
cleaning module 15-21 to be either coupled closely adjacent a
load/unload module 13, 23, or to allow a cleaning module 15-21 to
be coupled to an adjacent cleaning module 15-21 in a spaced
relationship such that the overall distance D (FIG. 1A) between the
wafer position in the first cleaning module and the wafer position
in the next adjacent cleaning module is equal to a fixed distance
(FIG. 1A). In this manner, each of the substrate supports 25a-e may
be equally spaced the distance X (FIG. 1A) from the adjacent
substrate supports 25 on either side thereof, provided all modules
have an overall width W.sub.n, less than or equal to the distance
X. Further, although the wafer position within any module need not
be centered between the front and back face of the module, the
distance between the wafer and the front face of the module and the
distance between the wafer and the back face of the module may be
less than or equal to one-half of X (the distance between adjacent
wafer supports) so as to preserve configurability.
[0029] A substrate transfer mechanism 31 having a plurality of
substrate handlers 33a-e is operatively coupled above the plurality
of modules 13-23. In this example, the substrate handlers 33a-e are
spaced by the distance X (FIG. 1A) and are equal in number to the
number (n) of modules 13-23 in a given cleaning system
configuration, minus one (n-1). The substrate transfer mechanism 31
is coupled so as to move the distance X (FIG. 1A), from a "load"
position wherein the first substrate handler 33a is positioned
above the load module 13, to an "unload" position, wherein the last
substrate handler 33e is positioned above the unload module 23. The
exemplary substrate handlers 33a-e are fixedly coupled
horizontally, and thus move horizontally as a unit. The exemplary
substrate handlers 33a-e are also fixedly coupled vertically, and
the substrate transfer mechanism 31 is movably coupled so as to
lift and lower a distance Y (FIG. 1B) from a position wherein each
substrate handler 33a-e operatively couples one of the substrate
supports 25a-f (so as to place or extract a wafer thereon or
therefrom), to a position wherein the lowest edge of each substrate
handler 33 is at an elevation above the highest edge of each module
13-23. Thus the substrate handler 33 also moves vertically as a
unit, between a "hand-off" position (wherein the substrate handlers
33a-e operatively couple the substrate supports 25a-f) as shown in
FIGS. 1A and 1D, and a "transport" position (wherein the substrate
handlers 33a-e are elevated above the modules) as shown in FIGS.
1B, 1C, 1E and 1F. The substrate handlers 33a-e may be removably
coupled to the substrate transfer mechanism 31 (e.g., via a latch,
etc.) so that each substrate handler may be easily removed or
replaced, allowing the cleaning system to be easily
reconfigured.
[0030] The operation of the inventive cleaning system 11 is
described with reference to the timing diagram of FIG. 2 and with
reference to the sequential views of FIGS. 1A-D, which show the
movement of the substrate transfer mechanism 31 as it loads/hands
off a plurality of single substrate batches, transports the
plurality of single substrate batches, and unloads/hands off the
plurality of single substrate batches.
[0031] FIG. 1A shows the cleaning system 11 during steady state
processing in the load/hand-off position. The substrate handlers
33a-e operatively couple the substrate supports 25a-e of the load
module 13, the megasonic cleaner 15, the first scrubber 17, the
second scrubber 19 and the spin-rinse-dryer 21 respectively, so as
to contact the edges of the semiconductor substrates S.sub.1-5
positioned thereon.
[0032] After gripping the substrates S.sub.1-5, the substrate
transfer mechanism 31 elevates the distance Y (FIG. 1B), to the
transport position shown in FIG. 1B. As the substrate transfer
mechanism 31 elevates, the substrate handlers 33a-e lift the
semiconductor substrates S.sub.1-5 from the substrate supports
25a-e, respectively. While in the transport position the substrate
transfer mechanism 31 indexes horizontally the distance X (FIG.
1A), from the load position wherein the first substrate handler 33a
is above the load module 13, and the last substrate handler 33e is
above the spin-rinse-dryer 21, to the unload position wherein the
first substrate handler 33a is above the megasonic cleaner 15, and
the last substrate handler 33e is above the unload module 23, as
shown in FIG. 1C. After indexing the distance X to the unload
position the substrate handlers 33a-e are respectively positioned
above the substrate supports 25b-f of the megasonic cleaner 15, the
first scrubber 17, the second scrubber 19, the spin-rinse-dryer 21
and the unload module 23.
[0033] The substrate transfer mechanism 31 then lowers the distance
Y to the unload/handoff position shown in FIG. 1D, wherein the
substrate handlers 33a-e operatively couple the substrate supports
25b-f, respectively. The substrate handlers 33a-e ungrip the
substrates S.sub.1-5, placing the substrates S.sub.1-5 on the
substrate supports 25b-f. The substrates S.sub.1-5 are processed
within the megasonic cleaner 15, the first scrubber 17, the second
scrubber 19 and the spin-rinse-dryer 21, respectively, while the
substrate transfer mechanism 31 elevates the distance Y (FIG. 1B)
to the transport position as shown in FIG. 1E. The semiconductor
substrates S.sub.1-5 continue processing within the cleaning
modules 15-21 while the substrate transfer mechanism 31 (still in
the transport position) indexes the distance X (FIG. 1A) from the
unload position to the load position shown in FIG. 1F.
[0034] While the substrate transfer mechanism 31 is indexing from
the unload position to the load position, the rotation mechanism
27b within the exemplary unload module 23, rotates the substrate
support 25f and the semiconductor substrate S.sub.5 positioned
thereon, from a vertical orientation to a horizontal orientation
and may optionally perform flat finding to place the semiconductor
substrate S.sub.5's flat in a known position. Also while the
substrate transfer mechanism 31 is indexing from the unload
position to the load position a horizontally oriented semiconductor
substrate S.sub.6 is loaded into the load module 13 (e.g., via a
substrate handler not shown). The rotation mechanism 27a within the
load module 13 then rotates the substrate support 25a and the
semiconductor substrate S.sub.6 positioned thereon, from a
horizontal orientation to a vertical orientation.
[0035] Alternatively, the substrate handlers 33a-e may have end
effectors configured to grasp flatted wafers regardless of their
orientation, such as those disclosed in U.S. patent application
Ser. No. 09/559,889, filed Apr. 26, 2000 (AMAT No. 3554) the entire
disclosure of which is incorporated herein by this reference.
Specifically, that application describes two opposing end effectors
each having two pairs of opposing surfaces for contacting the edge
of a substrate. Thus, the end effectors are designed to contact a
substrate at four points along its edges. If a substrate is
oriented such that a flatted region of the substrate is adjacent
one of the contacting points (e.g., one of the pairs of opposing
surfaces) the substrate may still be stabily supported by the
remaining three contact points. Each of the contact points may be
radiused to follow the circumference of the substrate to thus
ensure that contact occurs only along the substrates edges.
[0036] The load module may optionally perform flat finding to place
the semiconductor substrate S.sub.6's flat in a known position
where it will not be contacted by the substrate transfer mechanism
31. Each cleaning module may comprise a flat finding mechanism such
that a substrate's flat is in a known position when contacted by
the substrate transfer mechanism 31. For instance, the flat finder
described in U.S. patent application Ser. No. 09/544,660, filed
Apr. 6, 2000 (AMAT No. 3437/CMP/RKK) may be employed in the
spin-rinse-dryer 21. A flat finder which may be used in the
scrubbers 15, 17 and the megasonic tank 83 is described below with
reference to FIGS. 6A-B and 7A-B.
[0037] Alternatively, rather than employing flat finding, if the
substrate enters a module in a known position, a programmed
controller can return the substrate to that position because the
substrate supports of the various modules rotate the substrate at a
known rate, and the rotation time can be selected so as to return
the substrate to the known, "flat found" position provided the
substrate supports are designed (e.g. with roughened surfaces) so
as to prevent substrate slipping. After processing within the
cleaning modules 15-21 is complete, the substrate transfer
mechanism 31 lowers the distance X (FIG. 1A) to the load/handoff
position as shown in FIG. 1A. Thereafter the sequence repeats, with
the semiconductor substrate S.sub.5 being unloaded from the unload
module 23 (e.g., manually or by a substrate handler not shown)
while the substrate transfer mechanism 31 is in the position shown
in FIG. 1A or FIG. 1B.
[0038] The cleaning system 11 comprises a controller C operatively
coupled to the substrate transfer mechanism 31. The controller C
may comprise a program for moving the transfer mechanism 31 from a
load/hand off position in which one of the substrate handlers 33a-e
operatively couples the substrate support 25a of the load module 13
and the remaining wafer handlers each operatively couple the
substrate support of one of the cleaning modules 15-21, to a
transfer position in which the substrate handlers 33a-e are above
the input module 13 and above the cleaning modules 15-21. The
controller C is also programmed to shift the transfer mechanism 31
a distance X (FIG. 1A) such that each substrate handler 33a-e is
positioned above the substrate supports of a cleaning module 15-21
or of the unload module 23, and to lower the transfer mechanism 31
to an unload/handoff position in which the substrate handlers 33e
operatively couple the substrate support 25f of the unload module
23 and the remaining substrate handlers 33a-d each operatively
couple a substrate support of one of the cleaning modules 15-21.
Thus, the controller C may be programmed such that a plurality of
substrates are simultaneously stepped through the plurality of
single substrate load, clean and unload modules. Further, the
controller C may be coupled to the rotation mechanism 27a of the
load module 13 and to the rotation mechanism 27b of the unload
module 23. The controller program may change semiconductor
substrate orientation and may optionally perform flat finding at
the load and the unload modules 13 and 23, while the substrate
transfer mechanism 31 is in the transfer position, and/or may
return substrates to a known flat found position as previously
described.
[0039] As described above, and as best understood with reference to
the timing diagram of FIG. 2, substrate load/unload, orient and the
optional flat finding may occur while substrates are being
processed within the cleaning modules. Thus, in the exemplary
system of FIGS. 1A-F, the overall cleaning time of each
semiconductor substrate is equal to the cycles of transport and six
cycles of processing, and the cleaning modules operate continuously
except during substrate transport. In this example, the cleaning
modules 15-21 do not idle while substrates are loaded, unloaded,
oriented or flats are found. Therefore during steady state
processing, six semiconductor substrates exit the inventive
cleaning system during the overall cleaning time of a single
semiconductor substrate (i.e., during six cycles of transport and
processing), and the steady state throughput of the inventive
cleaning system equals the inverse of the sum of the transfer time
and the process time.
[0040] The inventive cleaning system, may be configured for
megasonically cleaning a substrate within a tank of fluid, followed
by scrubbing the substrate. Such a configuration may more
effectively remove large flat particles and particles located on
the beveled edge of a semiconductor substrate, than do conventional
systems which employ only megasonics or only scrubbers.
[0041] The input module 13 may comprise an interface module 41 as
shown in FIGS. 3A-C, if substrates are to be received in a vertical
orientation. FIGS. 3A-C are side perspective views of the inventive
interface module 41. The interface module 41 comprises a track 43
which is coupled to a motor by a timing belt (both not shown) and a
substrate cart 45 which is moveably coupled to the track 43. The
track 43 may be positioned on a slope in the Z direction
(represented by the angle ".beta." in FIG. 3B), by coupling one end
of the track 43 at a higher elevation than the other end of the
track 43 (as shown). Similarly, the track 43 may be slanted in the
X direction (represented by the angle ".alpha." in FIG. 3C). In
this manner the interface module 41 may be easily positioned in a
"3D" manner to receive a vertically oriented wafer from a wafer
handler (not shown) and to carry the wafer to a position where it
may be loaded into the cleaning module 15 of the cleaning system
11. Thus, the interface module 41 is easily adjustable to
facilitate substrate transfer between wafer handlers which may be
positioned at various angles.
[0042] For example, as shown in FIG. 4, a wafer handler 48 travels
along a track 50. The wafer handler 48 therefore may reach as far
as a location A. The cleaning system 11's substrate transfer
mechanism 31 requires a substrate S to be positioned at a location
B in order to be gripped by the substrate handler 33a thereof.
Accordingly, the interface module 41 is configured to extend
between locations A and B, which have differing elevations (angle
B) and differing locations in the X direction (angle .alpha.). The
track 43 extends between locations A and B, and the substrate cart
45 is coupled to the track 43 with an angle that places the
substrate cart 45 in line with wafer handler 48 when the substrate
cart 45 is in a transfer position (at location A) and in line with
substrate transfer mechanism 31 when the substrate cart 45 is in a
load position (at location B). In order to allow the substrate cart
45 to be easily positionable the substrate cart 45 preferably
comprises an adjustable arm, one end of which moveably couples the
track 43 (so as to move therealong) with an angle that may be
adjustable yet that may be fixed (e.g., once adjusted) so as to
remain constant between positions A and B. Both the position of the
track 43 (.alpha., .beta.) and the position of the substrate cart
45 relative to the track 43 may be easily adjustable so as to
facilitate interfacing of various wafer handlers within a
fabrication system.
[0043] Referring again to FIG. 3A, an optional wetting system 47
comprising a fluid collector 49, a splash back 51 which extends
upwardly from the backside of the fluid collector 49, and one or
more nozzles 53 which are mounted on the splash back 51 at a
position and angle so as to wet both surfaces of the substrate S.
For example, a spray bar 55 is positioned slightly above and, to
enable wafer exchange from overhead, slightly in front of or in
back of the substrate S, extends a length equal to the diameter of
the substrate S, and has a set of nozzles 53a angled to direct a
uniform line of fluid to the backsurface of the substrate S, and a
set of nozzles 53b angled to direct a uniform line of fluid to the
frontside of the substrate S. Either set of nozzles 53a, 53b may be
replaced with a linear or squall type nozzle that outputs a line of
fluid. The nozzles 53a, 53b are coupled to a fluid source 56. A
fluid outlet 57 is coupled to the bottom of the fluid collector 49
to drain or pump fluid therefrom.
[0044] Referring to FIGS. 5A-D, the substrate cart 45 comprises two
side rollers 59a, 59b, and a bottom roller 59c. Each of the rollers
has a central notch or groove 61 (FIG. 5A), having a side wall
angle (e.g., of 45.degree.) such that only the edge of the
substrate S contacts the rollers 59a-c. The notches thus reduce
damage to the front or back wafer surfaces. The rollers 59a-c are
positioned a sufficient distance apart so as to hold the substrate
S in a fixed position and to prevent substrate wobble.
[0045] In one aspect of the invention, in order to achieve
orientation of a substrate S having a flat f (FIG. 5), the bottom
roller 59c is motorized, and is therefore coupled to a motor 63
which may be remotely located or may be mounted on the backside of
the substrate cart 45. The side rollers 59a, 59b are configured to
roll freely, and are not motorized. The side rollers 59a, 59b are
positioned a sufficient distance apart so as to support the
substrate S such that the flat f does not contact the bottom roller
59c when the substrate S is supported by the side rollers 59a, 59b
(FIG. SC).
[0046] In operation, the substrate cart 45 travels along the track
43 to assume the transfer position (at location A), shown in
phantom in FIG. 4, and the wafer handler 48 travels along the track
50 carrying a substrate S to position A. The wafer handler 48
places the substrate S in the substrate cart 45 and the substrate
cart 45 begins to travel up the track 43 toward the load position
(location B). In this example, while the substrate cart 45 is
traveling along the track 43 fluid from the nozzles 53a, 53b
prevents the substrate S from drying. The fluid runs off the
substrate S into the fluid collector 49. The splash back 51
prevents fluid from splashing or otherwise exiting the vicinity of
the cleaning system 11. Any fluid which enters the substrate cart
45 drains therefrom via holes (not shown) to the fluid collector
49. Fluid collects in the fluid collector 49 and is drained
therefrom via the fluid outlet 57. Because the substrate preferably
is rotating (as described below), the nozzles 53a, 53b may be
positioned on the side, bottom, etc. Alternatively, the nozzles may
be stationarily positioned at the transfer location, the load
location or anywhere therebetween.
[0047] In one aspect, while the substrate cart 45 is traveling
along the track 43 toward the load position (location B), the
bottom roller 59c rotates, causing the substrate S to rotate
therewith. The side rollers 59a, 59b roll passively due to their
contact with the rotating substrate S. As soon as the flat f
reaches the bottom roller 59c, (FIG. 5C) the bottom roller 59c no
longer has sufficient frictional contact with the substrate S to
rotate the substrate S. By the time the substrate cart 45 reaches
the load position (location B), the substrate S will have been
rotated via the bottom roller 59c to a position where the leading
edge of the flat f is adjacent the bottom roller 59c. Accordingly,
the substrate handler 33 of the substrate transfer mechanism 31 can
grip the substrate S without risk of contacting the flat f, which
may cause the substrate handler 33 to drop the substrate S
(depending on the specific configuration of the substrate handler's
end effectors). Thereafter, the nozzles 53a, 53b turn off and the
substrate handler 33 grips the substrate S, the substrate transfer
mechanism 31 elevates and indexes forward to position the substrate
S above the first cleaning module 15, as previously described. As
soon as the substrate S is lifted from the substrate cart 45, the
substrate cart 45 may begin traveling along the track 43 toward the
transfer position (location A).
[0048] An alternative embodiment for orienting the substrate S is
shown in FIGS. 6A and 6B. In this embodiment, the side rollers 59a,
59b are coupled to the motor 63, and a sensor, generally
represented by the number 65 in FIGS. 6A-B, is coupled to the
bottom roller 59c for measuring the velocity of rotation thereof.
The sensor 65 may be an incremental encoder (e.g., a magnetic or
optical tachometer for measuring velocity of rotation) that is
capable of generating pulse frequencies proportional to roller
speed.
[0049] In operation, when the side rollers 59a, 59b rotate, the
substrate S rotates therewith. The friction between the rotating
substrate S and the bottom roller 59c causes the bottom roller 59c
to rotate. The bottom roller 59c may be damped, such that as soon
as the flat f reaches the bottom roller 59c and the bottom roller
59c looses contact with the edge of the wafer, the bottom roller
stops rotating. Accordingly the sensor 65 sends a signal to a
controller C. Thereafter, the controller C can signal the motor 63
to cease rotation of the side rollers 59a, 59c in which case the
substrate will be in a known position with the leading edge of the
flat f adjacent the bottom roller 59c. Alternatively the controller
may position the flat f in any other desired location by rotating
the rollers at a known speed for an appropriate period of time,
provided the rollers are designed to avoid substrate slippage.
[0050] In addition to flat finding, the "orienter" of FIGS. 6A and
6B can be used to monitor the rotation of a substrate, whether
flatted or not. When employed for rotation monitoring, any of the
supporting rollers may be coupled to rotate passively with the
wafer, and may have the sensor 65 coupled thereto.
[0051] A further embodiment for orienting the substrate S, or for
monitoring the rotation thereof, is shown in FIGS. 7A-C. This
embodiment is particularly well suited for use within a scrubber,
and is therefore shown within the first scrubber 17. A through-beam
sensor comprising a beam emitter 71 (e.g., an optical emitter) and
a receiver 73 (e.g., a photo diode) are mounted across from each
other on the front and back surfaces, respectively, of the scrubber
chamber 75. The emitter 71 and the receiver 73 are positioned at an
elevation where the beam emitted from the emitter 71 strikes the
surface of the substrate S, near its edge, and is therefore
prevented from reaching the receiver 73 unless the flat f is in the
region between the emitter 71 and the receiver 73, as shown in
FIGS. 7B and 7C. Like the embodiments of FIGS. 5A-6B, the emitter
71 and the receiver 73 are coupled to a controller C which
processes the information received therefrom.
[0052] The inventive orienting mechanisms of FIGS. 5A-7C are
applicable on their own (e.g., outside the cart 45) as well as
within any roller based system which rotates a single substrate.
Exemplary vertically oriented systems include but are not limited
to megasonic tanks, and scrubbers such as those previously
incorporated by reference. Similarly, the inventive
orienters/rotation monitors described herein are equally applicable
to any vertically or horizontally oriented system which rotates a
single substrate via a plurality of edge rollers, e.g., scrubbers
(with roller brushes or scanning disk brushes, etc.)
spin-rinse-dryers, edge cleaners, etc.
[0053] FIG. 8 is a schematic front elevational view of a substrate
support 77 that is particularly advantageous for rotating flatted
substrates. The inventive cleaning system 11 may employ the
substrate support 77 within any module that requires rotation. The
substrate support 77, however, may be used within any apparatus
that rotates a flatted wafer, and is not limited to use within the
cleaning apparatuses disclosed or incorporated herein.
[0054] The inventive substrate support 77 comprises four rollers
79a-d. The two bottom rollers 79b, 79c are spaced by a distance
equal to the length of the flat f, of the substrate S positioned on
the substrate support 77 (e.g., roller 79b and 79c may each be
positioned 29-291/2.degree. from normal). The remaining two rollers
79a, 79d may be positioned at any location so long as they contact
the edge of the substrate S. One or more of the rollers 77a-d is
coupled to a motor (not shown), and the remaining rollers (if any)
are adapted to roll freely when the substrate S rotates.
[0055] In operation, the motorized roller(s) are energized and the
substrate S begins to rotate. As the substrate S rotates at least
three of the four rollers 79a-d maintain contact with the substrate
S, despite the instantaneous position of the flat f. When at least
rollers 79a and 79d are both motorized, the substrate S will
rotate. However, the substrate S will rotate more smoothly, and
substrate/roller slippage may be completely avoided if all four
rollers 79a-d are motorized. Accordingly, this configuration is
particularly desirable for use within megasonic cleaners
(particularly tank type cleaners) or scrubbers where smooth
continuous substrate rotation provides more uniform cleaning, yet
is often difficult to achieve as the fluid employed within such
cleaning apparatuses may tend to increase substrate/roller
slippage.
[0056] The modularity of the inventive cleaning system allows for
any number of configurations. Exemplary cleaning system
configurations are as follows: [0057] 1. megasonic tank, scrubber,
scrubber, spin-rinse-dryer; [0058] 2. megasonic tank, scrubber,
spin-rinse-dryer; [0059] 3. megasonic tank, megasonic tank,
spin-rinse-dryer; [0060] 4. megasonic tank, spin-rinse-dryer;
[0061] 5. scrubber, megasonic tank, scrubber, spin-rinse-dryer;
[0062] 6. scrubber, scrubber, megasonic tank, spin-rinse-dryer;
[0063] 7. scrubber, megasonic tank, spin-rinse-dryer; [0064] 8.
megasonic tank, rinsing tank, spin-rinse-dryer; [0065] 9. megasonic
tank, megasonic rinsing tank, spin-rinse-dryer; [0066] 10.
megasonic tank, rinse, megasonic, rinse, spin-se-dryer; [0067] 11.
megasonic tank, scrubber, etch bath, rinse, spin-rinse-dryer;
[0068] 12. megasonic tank, megasonic rinse, etch bath, rinse,
spin-rinse-dryer; [0069] 13. megasonic rinse, etch, rinse,
spin-rinse-dryer; [0070] 14. etch bath, scrubber, megasonic tank,
spin-rinse-dryer; [0071] 15. etch bath, rinse, megasonic tank,
spin-rinse-dryer; and [0072] 16. etch bath, megasonic tank,
spin-rinse-dryer. An exemplary etch bath chemistry is diluted
hydrofluoric acid, and an exemplary cleaning solution (e.g., for
use in the scrubber, megasonic tank, etc.) is SC1.
[0073] Additionally, the input module and/or the output module may
be omitted and substrates may be loaded directly to the first
cleaning module, and/or unloaded directly from the last cleaning
module. Vertically oriented wafers may be loaded into the input
module and/or unloaded vertically from the output module (e.g., the
input module may comprise a chamber for receiving a vertically
orientated substrate and preventing the substrate from drying via
spray, submersion etc., and the output module may comprise a
location for receiving a vertically orientated substrate from the
cleaner's wafer handler, and for allowing another substrate handler
to extract the vertical substrate). In short, any combination of
vertical or horizontal load and unload modules may be employed as
may direct loading and unloading from the cleaning modules.
Further, Marangoni drying may be employed within a tank module or
within the spin-rinse-dryer 21, or in a separate Marangoni rinser
and drier. An exemplary Marangoni drying module which may replace
the spin-rinse-dryer 21 in the inventive cleaner is disclosed in
U.S. patent application Ser. No. 09/280,118, filed Mar. 26, 1999
(AMAT No. 2894/CMP/RKK), the entirety of which is incorporated
herein by this reference. Alternative Marangoni drying systems
which may replace both the spin-rinse-dryer 21 and the output
module are described with reference to FIGS. 9 and 10.
[0074] FIGS. 9 and 10 depict two embodiments of inventive Marangoni
Dryers. FIGS. 9A and 9B are a front elevational view of a first
embodiment of a first aspect of an inventive Marangoni drying
module 81a showing the exterior thereof, and respectively showing a
substrate receiving position and a substrate guiding position as
described below. FIG. 9C is a front elevational view of the
Marangoni drying module of FIG. 9B showing the interior thereof.
FIGS. 9D-F are sequential side elevational views of the Marangoni
drying module of FIGS. 9A-C useful in describing the operation
thereof.
[0075] Although the inventive Marangoni drying modules 81a, 81b may
be advantageously used within the cleaning system 11 (FIGS. 1A-F)
as the last module thereof, they may also be used as a stand alone
unit or as part of another cleaning system. The inventive Marangoni
drying module 81a comprises a wet chamber 83, a drying chamber 85
positioned above the wet chamber 83, and a dry chamber 87
positioned above the drying chamber 85. The dry chamber 87 is
coupled so that it may rotate either 90 or 180 degrees so as to
place a dry substrate in a desired vertical or horizontal
orientation as further described below.
[0076] The interior of the wet chamber 83 (FIG. 9C) comprises a
pair of substrate guide rails 89a-b which are adapted so as to move
between a substrate receiving position (shown with reference to
exterior view of FIG. 9A) wherein the guide rails 89 are positioned
so as not to block an incoming wafer handler (not shown), and a
substrate guiding position (shown with reference to the exterior
view of FIG. 9B) wherein the guide rails 89 are positioned so as to
contact the edges of a substrate and thus to restrict the lateral
movement thereof as the substrate is lifted from the wet chamber 83
to the dry chamber 87. Each of the guide rails 89a-b has a
permanent magnet 91a-b imbedded therein. A pair of guide rail
actuators 93a-b are mounted to an outside wall of the wet chamber
83 (FIGS. 9A-B). A bar 95a-b, respectively, having permanent
magnets 97a-b mounted thereto, is coupled to each guide rail
actuator 93a-b. The exterior bars 95a-b (FIGS. 9A-B) and the
interior pair of substrate guide rails 89a-b (FIG. 9C) are
positioned such that their respective permanent magnets 91a-b,
97a-b magnetically couple through the wall of the wet chamber
83.
[0077] The interior of the wet chamber 83 (FIG. 9C) further
comprises three substrate supports 99a-c, positioned to contact the
lower edge of a substrate supported thereby. Two of the substrate
supports (e.g. substrate supports 99a and 99c) are stationary,
while the remaining substrate support (e.g. substrate support 99b)
is movable. Specifically, the movable substrate support 99b has a
substrate supporting end 101a, and a guide rail mounting end 101b
(shown in the schematic side view of FIGS. 9D-F). The guide rail
mounting end 101b is slidably positioned between a pair of
substrate support guide rails 103a-b, which in turn are mounted to
the inside wall of the wet chamber 83. The guide rail mounting end
101b has a permanent magnet 105 (FIG. 9C) mounted thereto.
Positioned along the outside wall of the wet chamber 83 is a
substrate vertical motion assembly 107 (FIGS. 9D-F). The substrate
vertical motion assembly 107 comprises a pair of rails 109a-b which
support a sliding mechanism 111 (FIGS. 9A-B). The sliding mechanism
111 has a permanent magnet 113 mounted thereto so as to couple
through the wall of the wet chamber 83 to the magnet 105 mounted to
the movable substrate support 99b (FIG. 9C). The substrate vertical
motion assembly 107 further comprises a drive motor 114 drive motor
114, a belt drive 115 coupled to the drive motor 114 and a lead
screw 117 coupled so as to drive the sliding mechanism 111 along
the rails 109. The movable substrate support 99b also may comprise
a vacuum hole 119 (FIGS. 9D-F), coupled to a vacuum line 121 (FIGS.
9C).
[0078] The wet chamber 83 also comprises an overflow weir 123
having output holes 125 through which the overflow fluid is
drained. Additionally, a fluid inlet 126 (FIGS. 9A-B) is provided
for supplying fluid to the wet chamber 83.
[0079] The drying region 85 is located between the top of the
rinsing fluid contained in the wet chamber 83 and a bottom wall
129a of the dry chamber 87. Gas supply tubes 131a-b (FIGS. 9A-B)
are installed just above the rinsing fluid and so as to be on both
sides of a substrate being guided by guide rails 89a-b. Nozzles
(not shown) are formed in the gas supply tubes 131a-b by drilling
fine holes in the thin wall and forming horizontal slots beginning
at each fine hole and extending three-quarters of the wall
thickness toward the internal diameter of the tubes 131a-b. The
tubes 131a-b can be rotated to adjust the angle of vapor flow from
the nozzles.
[0080] The dry chamber 87 comprises a plurality of walls 129a-f
which form a sealed enclosure. Within the dry chamber 87 a second
pair of substrate guide rails 135a-b are positioned to receive and
guide a substrate as it is lifted from the wet chamber 83 through
the drying region 85 into the dry chamber 87. The second pair of
substrate guide rails 135a-b are positioned in line with the first
pair of substrate guide rails 89a-b that are mounted therebelow in
the wet chamber 83. The dry chamber 87 further comprises a vertical
motion stop 137 (FIGS. 9A-F) that is adapted to selectively extend
and retract so as to selectively allow substrate passage or provide
substrate support. To achieve such selective extension and
retraction, vertical motion stop 137 may magnetically couple
through a wall 129 of the dry chamber 87. The dry chamber 87 may
also comprise one or more substrate supports 139 (FIGS. 9C-F)
positioned to support a substrate as the substrate changes
orientation (e.g., changes from a vertical to a horizontal
orientation as described below with reference to FIGS. 9E-F). In
one aspect each of the second pair of substrate guide rails 135a-b,
the vertical motion stop 137, and the dry chamber substrate support
139 are coupled to a door 141 of the dry chamber 87. Accordingly in
this aspect, a substrate supported by the second pair of substrate
guide rails 135a-b, the vertical motion stop 137, and the dry
chamber substrate supports 139 will rotate with the door 141 as the
door 141 of the dry chamber 87 is opened (as shown and described
below with reference to FIGS. 9E-F).
[0081] The door 141 (FIG. 9A-B) of the dry chamber 87 is attached
to the front wall 129b of the dry chamber 87 via a hinge 143 (FIGS.
9D-F). The hinge 143 may be coupled to a motor or other actuator so
that the door 141 may be selectively opened and closed thereby.
Further, the entire dry chamber 87 is rotatably coupled to the
walls of the wet chamber 83 via a hinge 145 (FIGS. 9D-F). The hinge
145 may be coupled to a motor or the like so that the dry chamber
87 may be selectively rotated 180 degrees from the drying position
shown in FIG. 9D to the open position shown in FIG. 9E. A rotation
stop 147 (FIGS. 9D-F) may extend from a rear wall of the wet
chamber 83 a sufficient distance so as to stop the rotation of the
dry chamber 87 at a desired position (e.g. 180 degrees). Similarly,
a door rotation stop 149 may extend upwardly from a base plate 151
(FIGS. 9D-F), a sufficient distance so as to stop the rotation of
the dry chamber door 141 at a desired position (e.g., as shown in
FIG. 9F, a position 90 degrees from the closed position). An
additional support 153 (FIGS. 9D-F) may extend upwardly from the
base plate 151 so as to provide additional support for the door 141
when the door 141 is in the open position as shown in FIG. 9F.
[0082] The dry chamber 87 further comprises sealing mechanisms (not
shown) which ensure that the bottom wall 129a of the dry chamber 87
seals against the walls of the wet chamber 83, and ensure that the
door 141 seals against the front wall 129b of the dry chamber 87. A
gas inlet 155 (FIGS. 9A-C) is coupled through one of the walls 129
of the dry chamber 87 to supply gas to the dry chamber 87, so as to
dilute the flow of vapor entering the dry chamber 87 from the
drying region 85 and/or to pressurize the dry chamber 87. Further,
the bottom wall 129a of the dry chamber 87 comprises a slot (not
shown) that is slightly longer and wider than a substrate, and has
a hole that is slightly larger than the diameter of the movable
substrate support 99b. Accordingly a substrate may be transferred
from the wet chamber 83 through the drying region 85 and into the
dry chamber 87 via the slot (not shown), while the dry chamber 87
remains sealed to the walls of the wet chamber 83. Each moving part
of the Marangoni drying system 81a as well as the pumps (not shown)
which supply gases or fluids to the Marangoni drying system 81a are
coupled to a controller C which controls the operation of the
Marangoni drying system 81a as further described below.
[0083] In operation when a substrate S is to be loaded into the
Marangoni drying system 81a, the hinge 145 which couples the dry
chamber 87 to the wet chamber 83 rotates, causing the dry chamber
87 to rotate therewith to an open position, as shown in FIG. 9E.
When the dry chamber 87 has rotated 180 degrees the dry chamber 87
contacts the dry chamber rotation stop 147 and accordingly ceases
rotation. When the dry chamber 87 is in the open position (FIG.
9E), the wet chamber 83 is open and a substrate S may be inserted
therein. To make room for an incoming substrate handler 157 (FIGS.
9A-B) the guide rail actuators 93a-b move the bars 95a-b outwardly.
As the bars 95a-b move outwardly, the permanent magnets 97a-b
(which are coupled to the bars 95a-b) magnetically couple through
the wall of the wet chamber 83 to the permanent magnets 91a-b which
are mounted to the first pair of substrate guide rails 89a-b.
Accordingly the substrate guide rails 89a-b also move outwardly so
as to assume the substrate receiving position shown in FIG. 9A.
When the first pair of substrate guide rails 89a-b are in the
substrate receiving position and the movable substrate support 99b
is in the lower position as shown in FIG. 9C, the substrate handler
157 lowers the substrate S into the wet chamber 83, placing the
substrate S on the substrate supports 99a-c. Thereafter the
substrate handler 157 opens to release the substrate S and elevates
to a position above the Marangoni drying system 81a. The hinge 145
then rotates the dry chamber 87 180 degrees until the dry chamber
87 is again sealed against the walls of the wet chamber 83 in the
processing position as shown in FIG. 9D.
[0084] After the substrate S is positioned on the substrate
supports 99a-c, the guide rail actuators 93a-b move inwardly
causing the first pair of substrate guide rails 89a-b to assume the
substrate guiding position shown in FIG. 9B. To elevate the
substrate S the drive motor 114 is activated and motion therefrom
is transferred through the belt drive 115 to the lead screw 117.
The motion of the lead screw 117 causes the sliding mechanism 111
to slide upwardly along the rails 109 mounted to the outside of the
wet chamber 83. The permanent magnet 113 mounted to the sliding
mechanism 111 couples through the wall of the wet chamber 83 to the
magnet 105 mounted to the movable substrate support 99b.
Accordingly as the sliding mechanism 111 moves upwardly, so does
the movable substrate support 99b and, consequently, the substrate
S positioned thereon.
[0085] As the upper portion of the substrate S enters the drying
region 85 the upper portion of the substrate S leaves the pair of
substrate guide rails 89a-b and is sprayed with vapors (e.g., IPA
vapors) from the nozzles 133. The vapors mix with the film of fluid
that remains on the surface of the substrate S as the substrate S
is lifted from the fluid contained in the wet chamber 83. The
vapors lower the surface tension of the fluid film, resulting in
what is known as Marangoni drying. To enhance the Marangoni drying,
a second set of nozzles (not shown) may supply a rinsing fluid to
the surface of the substrate S as the substrate S is lifted from
the wet chamber 83. The rinsing fluid nozzles (not shown) and the
set of vapor nozzles 133 are positioned such that the vapor from
the nozzles 133 mixes with the fluid film formed on the wafer via
the rinsing fluid nozzles (not shown). The specific details of a
Marangoni drying process that employs such a set of rinsing fluid
nozzles is disclosed in commonly assigned U.S. patent application
Ser. No. 09/280,118, filed Mar. 26, 1999 (AMAT No. 2894/CMP/RKK)
the entire disclosure of which is incorporated herein.
[0086] After the upper portion of the substrate S passes the
nozzles 133 and is dried thereby, the upper portion of the
substrate S enters the dry chamber 87 via the slit (not shown) in
the dry chamber 87's bottom wall 129a, and is guided by the second
pair of substrate guide rails 135a-b as the substrate support 99b
continues to elevate the substrate S. After the entire surface of
the substrate S passes the vertical motion stop 137, the vertical
motion stop 137 extends from the front wall 129b of the dry chamber
87, to position a groove formed therein, in line with the edge of
the substrate S. Thereafter the movable substrate support 99b
lowers, and the substrate S lowers therewith until contacting the
vertical motion stop 137. Accordingly after contacting the vertical
motion stop 137 the substrate S is supported by the vertical motion
stop 137, by the second pair of substrate guide rails 135a-b, and
by any additional substrate supports 139 which are positioned along
the upper edge of the substrate S. As the moveable substrate
support 99b begins to lower, vacuum is applied to vacuum hole 119
and any fluid that may be trapped against the substrate by the
moveable substrate support 99b is suctioned from the substrate
surface.
[0087] After the movable substrate support 99b lowers past the
bottom wall 129a of the dry chamber 87, the hinge 145 is activated
and rotates the dry chamber 87 one hundred and eighty degrees until
the dry chamber 87 contacts the dry chamber rotation stop 147.
After the dry chamber 87 begins rotation, the bottom wall 129a of
the dry chamber 87 no longer seals against the wet chamber 83.
Accordingly, as soon as the dry chamber 87 has rotated to a
position where the dry chamber 87 no longer obstructs access to the
wet chamber 83, a substrate handler such as the substrate handler
33 of FIG. 9 may insert a new substrate within the wet chamber 83.
Thereafter, because the dry chamber 87 has rotated 180 degrees, the
dry chamber 87's front wall 129b, although still vertically
oriented, now faces rearwardly as shown in FIG. 9E. Thereafter the
door hinge 143 is activated and rotates the door 141 from the
vertically oriented positioned shown in FIG. 9E, wherein the door
141 seals against the front wall 129b of the dry chamber 87, to a
horizontal orientation wherein the door 141 is supported by the
door rotation stop 149 and the additional support 153. Because the
second pair of substrate guide rails 135a-b are coupled to the door
141, the substrate S is also horizontally oriented as shown in FIG.
9F. The horizontally oriented substrate S may now be extracted from
the Marangoni drying system 81a by a horizontal substrate handler
(not shown). Accordingly, the inventive Marangoni drying system
81a, when employed as the last cleaning module of the cleaner (FIG.
9), may eliminate the need for a separate output module.
Alternatively, if the mechanisms supporting the substrate are
appropriately configured, the substrate may be extracted vertically
from the dry chamber when the dry chamber has rotated 180.degree.
to the open position (FIG. 9E).
[0088] Note that the vertical motion stop 137 and the additional
substrate supports 139 may advantageously be separated by a
distance which is slightly greater than the diameter of the
substrate S. Accordingly as the substrate S changes orientation the
substrate S may be transferred from supporting contact with the
vertical motion stop 137 (FIG. 9A) to supporting contact with the
additional substrate supports 139 (FIGS. 9C-F). Thereafter,
provided the additional substrate supports 139 are mounted to the
door 141, the additional substrate supports 139 rotate with the
door 141 as the door 141 opens. However, because of the positioning
of the additional substrate supports 139 (e.g., below the substrate
S when the dry chamber 87 is upside-down, and along the inner edge
of the substrate S when the door 141 is in a horizontal position
(FIG. 9F), the additional substrate supports 139 do not interfere
with a horizontal wafer handler's extraction of the substrate S.
The inventive Marangoni drying system 81a of FIGS. 9A-F is
particularly advantageous for drying 200 mm substrates, although
other size substrates may also be dried thereby.
[0089] An alternative embodiment of the inventive Marangoni drying
system 81a is shown and described with reference to FIG. 10A, which
respectively shows a front elevational view of an alternative
Marangoni drying system 81b. FIGS. 10B-D are sequential side
sectional views of the Marangoni drying module of FIG. 10A, useful
in describing increased throughput thereof. The alternative
Marangoni drying system 81b is, for the most part, structurally and
functionally identical to the Marangoni drying system 81a of FIGS.
9A-F, accordingly only those aspects of the alternative Marangoni
drying system 81b which differ from the Marangoni drying system 81a
are described with reference to FIGS. 10A-D. Specifically, within
the alternative Marangoni drying system 81b, the second pair of
substrate guide rails 135a-b are mounted to the side walls 129c and
129d of the dry chamber 87. Further, the door 141 is mounted to the
top wall 129e of the dry chamber 87, and the additional substrate
support 139 is mounted to the door 141. The dry chamber rotation
stop 147 extends to a higher elevation (than that of FIGS. 9D-F),
such that the dry chamber rotation stop 147 contacts the dry
chamber 87 when the dry chamber 87 rotates to the horizontal
position as shown in FIGS. 10C-D. Accordingly, in operation, after
the substrate S is dry, and the movable substrate support 99c has
exited the dry chamber 87, the dry chamber 87 rotates 90 degrees
until the dry chamber 87 contacts, and is supported by, the dry
chamber rotation stop 147. Thereafter the door hinge 143 is
activated, and rotates, carrying the additional substrate support
139 out of contact with the substrate S. The horizontally oriented
substrate S may now be extracted from the Marangoni drying system
81b via a horizontal substrate handler (not shown).
[0090] Accordingly, the inventive Marangoni drying systems 81a-b,
when employed as the last cleaning module of the cleaning system 11
(FIGS. 1A-F) may eliminate the need for a separate output module.
The alternative Marangoni drying system 81b of FIGS. 10A-D is
particularly advantageous for drying 300 mm substrates, although
other size substrates may also be dried thereby.
[0091] The foregoing description discloses only the preferred
embodiments of the invention, modifications of the above disclosed
apparatus and method which fall within the scope of the invention
will be readily apparent to those of ordinary skill in the art. For
instance, each substrate handler may individually index the
vertical distance between the transport position and the handoff
position, allowing the substrate supports to be positioned at
varying elevations, and allowing individual substrates to receive
varying processing (e.g., to pass over a given module without being
processed therein). Likewise, a given module may have more than one
substrate support. Particularly, for example, it may be
advantageous to have two substrate supports within a megasonic
tank, and to have a separate mechanism (e.g., a mechanism
magnetically coupled through the chamber walls) for moving the
substrate supports, such that the desired substrate support is
positioned for substrate placement/extraction via the substrate
transfer mechanism. Accordingly, processing within the megasonic
tank may be twice as long as processing within the remaining
modules. In another such aspect the same spacing may be maintained
between the substrate supports of adjacent modules (e.g., between
the input module's substrate support and the first substrate
support within the megasonic tank, and between the second substrate
support within the megasonic tank and the scrubber module's
substrate support) and the wafer handlers which access the
substrate supports within the megasonic tank may be motorized such
that the grippers move horizontally so that the desired substrate
support is accessed (e.g., if the two megasonic tank substrate
supports are spaced a distance N, the grippers positioned
thereabove would be spaced a distance X+N). Either such
configuration may be employed within any of the respective modules
such that the substrate supports and/or the grippers may be spaced
variable distances and still achieve simultaneous wafer transfer
from one module to the next.
[0092] Substrate orientation horizontal to vertical may occur
outside the inventive cleaning system, thus the load/unload modules
would not require rotation mechanisms. Similarly, flat finding may
be performed outside the inventive cleaning system. The specific
order and number of cleaning modules can vary, as can the relative
positioning of the modules and the shape of the transfer mechanism
(e.g., circular, rectangular, etc.). Finally, as used herein, a
semiconductor substrate is intended to include both an unprocessed
wafer and a processed wafer having patterned or unpatterned
material layers formed thereon.
[0093] Within the inventive cleaning system the plurality of
modules (megasonic tank, scrubbers, dryers, input/output, etc.) may
support a substrate in a roughly vertical orientation. By
supporting the disks at an angle which is not exactly 90 degrees
from horizontal (i.e., roughly vertical), the substrates are in a
known position which is much easier and more repeatably obtained,
than is a perfectly vertical position. Although the exact angle may
vary, a range of -10 to 10 degrees from normal is presently
preferred and 88.5 degrees is presently most preferred. The wafer
supports (e.g., the megasonic tank, scrubber, input/output rollers,
the SRD gripper fingers and the substrate handler's pocket or clamp
type grippers) each define a plane which is 88.5 degrees. This 88.5
degree plane is achieved by tilting each of the modules. Thus, each
wafer plane is parallel to the walls of the module. Alternatively,
just the supports may be tilted. Wafers are preferably lowered into
each module from overhead where they are supported by grippers that
also define a tilted plane (e.g., 88.5 degrees). The wafers are
lifted and lowered with a normal (90 degree) motion, but the wafers
themselves are tilted during transport.
[0094] Throughout the cleaning system the wafer is preferably
tilted the same degree and the same direction. However, the degree
and direction of the wafer's tilt may vary from module to module if
desired, in which case the wafer transfer robot may be configured
so as to adjust the degree and direction of the wafer tilt. In one
aspect, a wafer is tilted toward its backside, as this orientation
will provide better laminar airflow (which is generally provided
from overhead) to the frontside of the wafer.
[0095] Accordingly, while the present invention has been disclosed
in connection with the preferred embodiments thereof, it should be
understood that other embodiments may fall within the spirit and
scope of the invention, as defined by the following claims.
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