U.S. patent application number 13/750226 was filed with the patent office on 2013-08-15 for substrate cleaning technique employing multi-phase solution.
The applicant listed for this patent is John M. de Larios, Erik M. Freer, Mikhail Korolik, Michael Ravkin, Fritz C. Redeker. Invention is credited to John M. de Larios, Erik M. Freer, Mikhail Korolik, Michael Ravkin, Fritz C. Redeker.
Application Number | 20130206182 13/750226 |
Document ID | / |
Family ID | 39938699 |
Filed Date | 2013-08-15 |
United States Patent
Application |
20130206182 |
Kind Code |
A1 |
Freer; Erik M. ; et
al. |
August 15, 2013 |
SUBSTRATE CLEANING TECHNIQUE EMPLOYING MULTI-PHASE SOLUTION
Abstract
Apparatus, methods, and computer programs for cleaning opposed
surfaces of a semiconductor wafer are presented. One apparatus
includes first, second, and third valves, and one or more second
drains. The first valves are coupled to a supply of rinsing
solution and to first throughways that are coupled to an immersion
tank above a region in the immersion tank, the region being defined
by an area occupied by the substrate when the substrate is disposed
vertically on a support within the immersion tank. The second
valves are coupled to first drains and to second throughways that
are coupled to the immersion tank below the region, and the third
valves are coupled to a supply of cleaning solution and to third
throughways that are coupled to the immersion tank below the
region. Further, the second drains are coupled to fourth
throughways that are coupled to the immersion tank above the
region.
Inventors: |
Freer; Erik M.; (Mountain
View, CA) ; de Larios; John M.; (Palo Alto, CA)
; Ravkin; Michael; (Los Altos, CA) ; Korolik;
Mikhail; (San Jose, CA) ; Redeker; Fritz C.;
(Fremont, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Freer; Erik M.
de Larios; John M.
Ravkin; Michael
Korolik; Mikhail
Redeker; Fritz C. |
Mountain View
Palo Alto
Los Altos
San Jose
Fremont |
CA
CA
CA
CA
CA |
US
US
US
US
US |
|
|
Family ID: |
39938699 |
Appl. No.: |
13/750226 |
Filed: |
January 25, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11743283 |
May 2, 2007 |
8388762 |
|
|
13750226 |
|
|
|
|
Current U.S.
Class: |
134/26 ;
134/98.1 |
Current CPC
Class: |
H01L 21/02057 20130101;
H01L 21/02052 20130101; H01L 21/67751 20130101; H01L 21/67034
20130101; H01L 21/67057 20130101 |
Class at
Publication: |
134/26 ;
134/98.1 |
International
Class: |
H01L 21/02 20060101
H01L021/02 |
Claims
1. An apparatus for cleaning a substrate, the apparatus comprising:
a plurality of first valves coupled to a supply of rinsing solution
and to a plurality of first throughways that are coupled to an
immersion tank above a region in the immersion tank, the region
defined by an area occupied by the substrate when the substrate is
disposed vertically on a support within the immersion tank; one or
more second valves coupled to one or more first drains and to one
or more second throughways that are coupled to the immersion tank
below the region; a plurality of third valves coupled to a supply
of cleaning solution and to a plurality of third throughways that
are coupled to the immersion tank below the region; and one or more
second drains coupled to one or more fourth throughways that are
coupled to the immersion tank above the region.
2. The apparatus as recited in claim 1, wherein the plurality of
first valves includes: a left first valve disposed to the left of
the region; and a right first valve disposed to the right of the
region.
3. The apparatus as recited in claim 1, wherein the plurality of
third valves further includes: a left third valve disposed to the
left of the region; and a right third valve disposed to the right
of the region.
4. The apparatus as recited in claim 1, wherein the one or more
second drains further include: a left second drain disposed to the
left of the region; and a right second drain disposed to the right
of the region.
5. The apparatus as recited in claim 1, wherein the one or more
first drains include a bottom first drain, wherein a second
throughway is disposed at a bottom of the immersion tank.
6. The apparatus as recited in claim 1, further including: a
plurality of fourth valves coupled to a second supply of rinsing
solution and to the plurality of first throughways.
7. The apparatus as recited in claim 1, further including: a
plurality of fifth valves coupled to a third supply of rinsing
solution and to the plurality of third throughways.
8. The apparatus as recited in claim 1, further including: a pump
coupled to the one or more second drains.
9. The apparatus as recited in claim 1, wherein the rinsing
solution is isopropyl alcohol.
10. The apparatus as recited in claim 1, wherein the rinsing
solution is de-ionized water.
11. An apparatus for cleaning a substrate, the apparatus
comprising: a plurality of first valves coupled to a supply of a
first rinsing solution and to a plurality of first throughways that
are coupled to an immersion tank above a region in the immersion
tank, the region defined by an area occupied by the substrate when
the substrate is disposed vertically on a support within the
immersion tank; a plurality of second valves coupled to one or more
first drains and to a plurality of second throughways that are
coupled to the immersion tank below the region; a plurality of
third valves coupled to a supply of cleaning solution and to a
plurality of third throughways that are coupled to the immersion
tank below the region; and a plurality of fourth valves coupled to
a supply of a second rinsing solution and to the plurality of first
throughways; a plurality of fifth valves coupled to a supply of a
third rinsing solution and to the third throughways; and one or
more second drains coupled to fourth throughways that are coupled
to the immersion tank above the region.
12. The apparatus as recited in claim 11, wherein the plurality of
first valves includes: a left first valve disposed to the left of
the region; and a right first valve disposed to the right of the
region.
13. The apparatus as recited in claim 11, wherein the plurality of
third valves further includes: a left third valve disposed to the
left of the region; and a right third valve disposed to the right
of the region.
14. The apparatus as recited in claim 11, wherein the one or more
second drains further include: a left second drain disposed to the
left of the region; and a right second drain disposed to the right
of the region.
15. The apparatus as recited in claim 11, further including: a pump
coupled to the one or more second drains.
16. A method for cleaning a substrate, the method comprising:
placing the substrate on a support in an immersion tank without any
solution in the immersion tank; activating a plurality of first
valves to provide a first flow of a rinsing solution to the
immersion tank, the rinsing solution entering the immersion tank
above the substrate; activating a plurality of second valves after
deactivating the plurality of first valves to drain the rinsing
solution, the rinsing solution exiting the immersion tank below the
substrate; activating a plurality of third valves to provide a
second flow of a cleaning solution to the immersion tank, the
cleaning solution entering the immersion tank below the substrate;
and activating a pump to drain the cleaning solution, the cleaning
solution exiting the immersion tank above the substrate.
17. The method as recited in claim 16, wherein the first flow and
the second flow move in opposite directions.
18. The method as recited in claim 16, wherein the first flow moves
in a direction of gravity.
19. The method as recited in claim 16, wherein the second flow
moves in a direction opposite of gravity.
20. The method as recited in claim 16, wherein operations of the
method are performed by a computer program when executed by one or
more processors, the computer program being embedded in a
non-transitory computer-readable storage medium.
Description
CLAIM OF PRIORITY
[0001] This application is a Continuation Application under 35 USC
.sctn.120 and claims priority from U.S. application Ser. No.
11/743,283, entitled "Substrate Cleaning Techniques Employing
Multi-Phase Solution," filed May 2, 2007, which is herein
incorporated by reference.
CROSS REFERENCE TO RELATED APPLICATIONS
[0002] This application is related to U.S. patent application Ser.
No. 10/608,871, filed Jun. 27, 2003, and entitled "Method and
Apparatus for Removing a Target Layer from a Substrate Using
Reactive Gases"; U.S. Pat. No. 7,441,299, filed on Mar. 31, 2004,
and entitled "Apparatuses and Methods for Cleaning a Substrate";
U.S. Pat. No. 7,452,408, filed on Jun. 30, 2005, and entitled
"System and Method for Producing Bubble Free Liquids for Nanometer
Scale Semiconductor Processing"; U.S. Pat. No. 8,043,441, filed on
Jun. 15, 2005, and entitled "Method and Apparatus for Cleaning a
Substrate Using Non-Newtonian Fluids"; U.S. Pat. No. 7,416, 370,
filed on Jun. 15, 2005, and entitled "Method and Apparatus for
Transporting a Substrate Using Non-Newtonian Fluid"; U.S. Pat. No.
8,323,420, filed on Jun. 30, 2005, and entitled "Method for
Removing Material from Semiconductor Wafer and Apparatus for
Performing the Same"; U.S. Pat. No. 7,568,490, filed on Dec. 23,
2003, and entitled "Method and Apparatus for Cleaning Semiconductor
Wafers using Compressed and/or Pressurized Foams, Bubbles, and/or
Liquids"; U.S. Pat. No. 7,648,584, filed on Jan. 20, 2006, and
entitled "Method and Apparatus for Removing Contamination from
Substrate"; U.S. Pat. No. 7,737,097, filed on Feb. 3, 2006, and
entitled "Method for Removing Contamination from a Substrate and
for Making a Cleaning Solution"; U.S. Pat. No. 7,696,141, filed on
Feb. 3, 2006, and entitled "Cleaning Compound and Method and System
for Using the Cleaning Compound"; U.S. patent application Ser. No.
11/543,365, filed on Oct. 4, 2006, and entitled "Method and
Apparatus for Particle Removal"; and U.S. patent application Ser.
No. 11/732,603, filed on Apr. 3, 2007, and entitled "Method for
Cleaning Semiconductor Wafer Surfaces by Applying Periodic Shear
Stress to the Cleaning Solution". The disclosure of each of these
related applications is incorporated herein by reference for all
purposes.
BACKGROUND
[0003] There exists a desire to reduce critical dimensions of
features in electronic substrate products. As the features decrease
in size, the impact of contaminants during processing of the
features increases, which may produce defects. Exemplary
contaminants are particulates that include polysilicon slivers,
photoresist particles, metal oxide particles, metal particles,
slurry residue, dust, dirt, as well as various molecules containing
atoms such as carbon, hydrogen, and/or oxygen. Particulates
frequently adhere to a substrate surface by weak covalent bonds,
electrostatic forces, van der Waals forces, hydrogen bonding,
coulombic forces, or dipole-dipole interactions, making removal of
the particulates difficult.
[0004] Historically, particulate contaminants have been removed by
a combination of chemical and mechanical processes. These processes
employ cleaning tools and agents that have a probability of
introducing additional contaminants during a cleaning process.
[0005] Another technique for cleaning a substrate surface omits the
use of chemical agents by exposing the surface to high heat to
vaporize contaminants present thereon. The vapors are removed by
evacuating a chamber in which the substrate surface is present. The
high temperatures required for this process limits its application
to post deposition processes not involving material having a
structure that varies at temperatures proximate to the vaporization
temperature of the contaminants.
[0006] Another cleaning technique is disclosed in U.S. Pat. No.
6,881,687 and employs a laser-clean yield-enabling system. The
system incorporates a laser cleaning operation working in
conjunction with a defect inspection operation cooperating to feed
information regarding the root cause of remaining defects back to
earlier process stages, for correction of the root causes, with
resultant improvement in yield. In a simplest configuration, the
particles remaining after a laser cleaning would be characterized
as to their types, sizes, shapes, densities, locations, and
chemical compositions in order to deduce the root causes of the
presence of those particular particles. This information is used to
improve the yield of subsequent product wafers being processed so
that their yields are higher than the wafers characterized. It is
desired, however, to provide a more robust cleaning process that
avoids the presence of particulate contaminants remaining on the
surface that has been subjected to a cleaning process.
[0007] Therefore, a need exists to provide improved techniques to
clean substrate surfaces.
SUMMARY OF THE INVENTION
[0008] A method and system for cleaning opposed surfaces of a
semiconductor substrate having contaminants thereon. In one
embodiment the method includes concurrently generating relative
movement between a plurality substrates and a solution by exposing
a cassette having the substrates contained therein to the solution.
The solution has coupling elements entrained therein and the
relative movement imparts sufficient drag upon a subset of the
coupling elements to create movement of the coupling elements of
the subset within the solution and impart a quantity of the drag
upon the contaminant to cause the contaminant to move with respect
to the substrate.
[0009] Another embodiment is directed to a method that includes
generating relative movement between a fluid and the substrate. The
relative movement is in a direction that is transverse to a normal
to one of the opposed surfaces and creates two spaced-apart flows.
Each of the flows is adjacent to one of the opposed surfaces that
is different from the opposed surface that is adjacent to the
remaining flow of the plurality of flows. The fluid has coupling
elements entrained therein, and the relative movement is
established to impart sufficient drag upon the contaminants with to
move the contaminants with respect to the substrate. Other aspects
and advantages of the invention will become more apparent from the
following detailed description, taken in conjunction with the
accompanying drawings, illustrating by way of example the present
invention.
[0010] In another embodiment, an apparatus includes first valves,
second valves, third valves, and one or more second drains. One
apparatus includes first, second, and third valves, and one or more
second drains. The first valves are coupled to a supply of rinsing
solution and to first throughways that are coupled to an immersion
tank above a region in the immersion tank, the region being defined
by an area occupied by the substrate when the substrate is disposed
vertically on a support within the immersion tank. The second
valves are coupled to first drains and to second throughways that
are coupled to the immersion tank below the region, and the third
valves are coupled to a supply of cleaning solution and to third
throughways that are coupled to the immersion tank below the
region. Further, the second drains are coupled to fourth
throughways that are coupled to the immersion tank above the
region.
[0011] In yet another embodiment, a method includes an operation
for placing the substrate on a support in an immersion tank without
any solution in the immersion tank, and an operation for activating
a plurality of first valves to provide a first flow of a rinsing
solution to the immersion tank, the rinsing solution entering the
immersion tank above the substrate. A plurality of second valves is
activated after deactivating the plurality of first valves to drain
the rinsing solution, the rinsing solution exiting the immersion
tank below the substrate. The method further includes an operation
for activating a plurality of third valves to provide a second flow
of a cleaning solution to the immersion tank, the cleaning solution
entering the immersion tank below the substrate. A pump is
activated to drain the cleaning solution, which exits the immersion
tank above the substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The present invention will be readily understood by the
following detailed description in conjunction with the accompanying
drawings, and like reference numerals designate like structural
elements.
[0013] FIG. 1 is a plan view of a substrate processing system
including the present inventions.
[0014] FIG. 2 is a simplified side view of an exemplary substrate
cleaning system in accordance with one embodiment of the present
invention.
[0015] FIG. 3 is a side view of an immersion tank shown in FIG. 2
and substrate transport system taken along lines 3-3.
[0016] FIG. 4 is a plan view showing a liquid employed to remove
particulate contaminants from a substrate surface in accordance one
embodiment of the present embodiment.
[0017] FIG. 5 is demonstrating the relative cross-sectional areas
of malleable regions in the suspension in relation to contaminants
in FIG. 4 in accordance with the present invention.
[0018] FIG. 6 is plan view of a liquid employed shown in FIG. 4
demonstrating the forces exerted on a particulate in furtherance of
removing the particulate contaminant from the wafer surface in
accordance with the present invention.
[0019] FIG. 7 is a flow diagram demonstrating a process for
cleaning a substrate shown in FIGS. 2 and 3.
[0020] FIG. 8 is a cross-section view of the immersion tank shown
in FIG. 4 in accordance with an alternate embodiment.
[0021] FIG. 9 is a plan view showing a liquid employed to remove
particulate contaminants from a substrate surface in accordance
with another embodiment of the present invention.
[0022] FIG. 10 is a perspective view of a system employed to clean
substrates in accordance with an alternate embodiment.
[0023] FIG. 11 is a cross-sectional view of immersion tanks shown
in FIG. 10.
[0024] FIG. 12 is an alternate embodiment of one of the immersion
tanks shown in FIGS. 10 and 11.
[0025] FIG. 13 is an alternate embodiment of one of the immersion
tank shown in FIG. 11.
[0026] FIG. 14 a cross-section of the immersion tank shown in FIG.
13 with a lid removed.
DETAILED DESCRIPTION OF THE INVENTION
[0027] In the following description numerous specific details are
set forth in order to provide a thorough understanding of the
present invention. It will be apparent, however, to one skilled in
the art that the present invention may be practiced without some or
all of these specific details. In other instances, well known
process operations have not been described in detail in order not
to unnecessarily obscure the present invention.
[0028] Referring to FIG. 1 an embodiment of the present invention
is included in a substrate processing system that includes a
plurality of processing modules arranged is what is commonly
referred to as a cluster tool 10. Cluster tool 10 is typically
positioned within a clean room 12 that is defined, in part, by
surrounding walls 14. The modules of cluster tool 10 typically
include one or more load/unload stations, two of which are shown as
16 and 18. The atmosphere inside of cluster tool 10 is controlled
to minimize, if not prevent, exposure of substrate to the ambient
of clean room 12 during processing. Stations 16 and 18 facilitate
transportation of a substrate 20 between clean room 12 and modules
of cluster tool 10. From one of stations 16 and 18, substrate 20 is
introduced into a lab-ambient controlled module 22 to facilitate
wet processing may be performed.
[0029] Access to wet processing modules 24, 26 and 28 by substrate
20 is gained through lab-ambient control transfer module 22.
Lab-ambient control transfer module 22 functions to ensure that
substrate 20 reaming dry before entry into each of wet processing
modules 24, 26 and 28. To that end, each of wet processing modules
24, 26 and 28 functions to surfaces of substrate 20 dry upon
completion of processing. Access to plasma processing modules 30
and 32, after cleaning of substrate 20, is achieved through load
lock 34 and vacuum transfer module 36.
[0030] Vacuum transfer module 36 interfaces with plasma processing
modules 30 and 32 that may be any plasma vapor deposition
processing systems known that is suitable for depositing films upon
semiconductor substrate, e.g., one or more of plasma processing
modules may be a plasma enhanced chemical vapor deposition PECVD
system. Were substrate 20 to undergo processing in
plating/deposition module 38 or etch processing in etch system
module 40 before/after or without undergoing plasma processing, a
traversal through load lock 42. After traversing load lock 42,
substrate enters Controlled Ambient Transfer Module 44 that
facilitates access to modules 38 and 40 without exposing substrate
to the ambient of clean room 12.
[0031] In fluid and electrical communication with modules 16, 18,
20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42 and 44 is an
environmental control system 50 that regulates the operations of
each of modules 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40,
42 and 44 so that the environment present therein is suitable for
the processing desired. An example of cluster tool is discussed in
U.S. patent application Ser. No. 11/639,752 that is incorporated by
reference herein.
[0032] Referring to both FIGS. 1 and 2, an embodiment of one or
more of wet processing modules 24, 26 and 28 of FIG. 1 includes a
body 51 formed from any suitable material such as aluminum, plastic
and the like. Body 51 defines an immersion tank 52 that is
spaced-apart from an end 53 defining a void 54 therebetween through
which conduits 55 pass to place immersion tank 52 in fluid
communication with additional systems (not shown). A tank opening
57 is disposed opposite to the closed end 58 of immersion tank 52.
Positioned opposite to opening 57 is a shelving system 60. One or
more bases 61 may be disposed upon shelving system 60. Shelving
system 60 operates to reciprocate between a first position
proximate to opening 57 (as shown) and a second position located
remotely with respect to opening 57. To that end, a track 62 is
provided along which shelving system 60 moves. In the second
position, opening 57 is unobstructed, allowing access to immersion
tank 52.
[0033] Disposed upon base 61 is a substrate cassette 63 that
operates to retain substrates, such as semiconductor substrate 64.
To move substrates 64 between cassette 63 and tank 52 a substrate
transport system (STS) 65 is positioned proximate to immersion tank
52. STS 65 includes a robot 66, with a picker arm 67 coupled
thereto. Picker arm 67 has a picker 68 coupled thereto that has end
effector 69. Picker arm 67 is controlled by robot 66 to move and
index the picker 68 with respect to immersion tank 52 enable
positioning of end effector 69 in immersion tank 52. To that end,
robot 66 may include a stepper motor, a servo motor, or other type
of motor to provide precise control of the picker arm 67. Picker
arm 67 is configured to pivot end effector 69 to extend along two
transversely orientated planes to facilitate movement of substrates
64 from cassette 63 into cassette 70, disposed in tank 52. To that
end, end effector 69 is provided with suitable size and
functionality to manipulate substrates 64.
[0034] In the present example STS 65 is shown with picker arm 67
positioned on the exterior of immersion tank 52. STS 65 facilitates
insertion of picker 68 into immersion tank 52 to a level lower than
substrates 64 disposed in cassette 70. As a result, substrates 64
may be processed in immersion tank 52 to remove particulate matter
present on the surfaces of substrate 64. To that end, immersion
tank 52 includes a cleaning solution 71 of sufficient quantity to
allow most, if not the entire area, of all surfaces of substrates
64 to be covered by the same.
[0035] Referring to FIGS. 2, 3 and 4, with shelving system 60 in
the second position opening 57 is exposed, allowing unobstructed
access to introduce, and retain, cassette 70 in tank 52 vis-a-vis
hanger 72 that is attached to hanger arm 73. Hanger arm 73 is
coupled to a motor (not shown) to vary a position of cassette 70 in
immersion tank 52. In one embodiment of the present invention, STS
65 is used to move cassette 70 into immersion tank 52 when loaded
with multiple substrates 64. In this fashion, batch processing of
substrates 64 may be undertaken during a cleaning process. For
example, substrate 64 may have contaminants 75 thereon. Immersion
tank may be filled with solution. Picker arm 67 couples to detent
77 on cassette 70 to move the same into and out of immersion tank
52. The movement of cassette 70 in solution loosens, softens,
dislodges, or otherwise enhances the removal of residues, chemicals
and particulates, referred to as contaminants 75, from surfaces of
substrates 64. The speed at which cassette 70 is introduced into
immersion tank 52 is established to facilitate removal of
contaminants 75 from substrates 64. Specifically, solution is
fabricated to have the appropriate characteristics to interact with
contaminants 75 and remove the same from the surfaces of substrate
64. Similarly, the speed at which cassette 70 is removed from
solution 71 also facilitates removal of contaminants from substrate
64. As a result, it is possible to introduce cassette 70 and
substrates into immersion tank 52 before solution 71 is present.
After cassette 70 and substrate 64 are present in immersion tank
52, solution 71 is introduced and the movement of solution 71 with
respect to each of substrates 64 facilitates removal of
contaminants 75 therefrom. After removal of substrate 64 from
immersion tank 52, the same may be exposed to a rinse process to
remove solution 71 and/or loosens contaminants that remain. This
may occur, for example, in one of the remaining wet processing
modules 24, 26 and 28 by inserting the cassette 70 full of
substrate 64 into a tank (not shown) into a rinse state having a
solution of de-ionized water DIW or a solution of IPA to facilitate
a batch rinse. It should be understood that STS 65 may be employed
to remove each substrate 64, individually, from cassette 70 by
picker arm 67, which lifts the same into space 76 where substrate
64 is retrieved by robot 66 for movement to a rinse station that is
well known in the art.
[0036] Referring to both FIGS. 3 and 4, an exemplary material that
may form solution 71 includes a suspension 90 having multiple
regions, with differing flow characteristics so that the flow
characteristics associated with one of the regions differs from the
flow characteristics associated with the remaining regions. In the
present example, suspension 90 includes a liquid region 92 and a
coupling element 94. Liquid region 92 has a first viscosity
associated therewith. Coupling element 94 may comprise rigid solid
bodies, malleable solid bodies or solid bodies having fluidic
characteristics, i.e., solid bodies having a viscosity that is much
greater than the viscosity associated with liquid region 92.
Coupling elements 94 are entrained throughout a volume of liquid
region 92 such that liquid region 92 functions as a transport for
coupling elements 94 in furtherance of placing coupling elements 94
proximate to particulate contaminants 75 present on a surface 98 of
substrate 64.
[0037] Coupling elements 94 consist of a material capable of
removing contaminants 75 from surface 98 through transfer of forces
from suspension 90, i.e., movement of liquid regions 92, to
contaminant 75 vis-a-vis coupling elements 94. Thus, it is desired
to provide coupling elements 94 with a cross-sectional area
sufficient to remove contaminant 75 from surface 98. Typically, the
cross-sectional area of coupling elements 94 is greater than a
cross-sectional area of contaminant 75. In this manner, movement of
contaminant 75 in response to a drag force {right arrow over
(F)}.sub.d acting upon coupling element 94 is facilitated, with the
understanding that drag force {right arrow over (F)}.sub.d includes
both a frictional forces {right arrow over (F)}.sub.f, and normal
forces, with the normal forces including momentum. Drag force
{right arrow over (F)}.sub.d is a function of the physical
properties and relative velocities associated with liquid region 92
and coupling elements 94.
[0038] Friction force {right arrow over (F)}.sub.f, the tangential
component of drag force {right arrow over (F)}.sub.d, on the
surface of contaminant 75 is a function of the shear stress at the
contaminant surface multiplied by the surface area of the
contaminant: {right arrow over (F)}.sub.f={right arrow over
(.tau.)}A. The friction force {right arrow over (F)}.sub.f acting
upon the coupling element is the shear stress at the coupling
element surface multiplied by the surface area of the coupling
element: {right arrow over (F)}.sub.f={right arrow over (.tau.)}A.
A coupling element 94 in contact with contamination 96 directly
transfers its friction force. Thus, the contaminant experiences an
apparent shear stress that is a ratio of the coupling element 94 to
contaminant 75 surface areas. Specifically, the apparent shear
force {right arrow over (.tau.)}.sub.c to which contaminant
experiences is
.tau. -> c = .tau. -> A / A c ##EQU00001##
[0039] Where A is the cross-section area of coupling element 94 and
A.sub.c is the cross-sectional area of contaminant 75. Assume, for
example, that an effective diameter, D, of contaminant 75 is less
than about 0.1 micron and a width, W, and length, L, of coupling
element 94 are each between about 5 microns to about 50 microns.
Assuming a thickness, t, of coupling element 94 is between about 1
to about 5 microns, the ratio (or stress multiplier) could range
between 2,500 to about 250,000. This number will increase when the
normal forces are included in the drag force {right arrow over
(F)}.sub.d calculation. Coupling element 94, shown in FIG. 5, is
discussed with respect to being a hexahedron for ease of
discussion. However, it should be understood that coupling elements
are of substantially arbitrary shapes and that the length, L,
width, W, and thickness, t, referred to above is the average value
for coupling elements 94 in suspension.
[0040] Referring to FIG. 6, forces transferred to contaminant 75
vis-a-vis coupling elements 94 occur through coupling of coupling
elements 94 to contaminant through one or more various mechanisms.
To that end, liquid region 92 exerts a downward force {right arrow
over (F)}.sub.D on coupling elements 94 within liquid region 92
such that coupling elements 94 are brought within close proximity
or contact with contaminants 75 on surface 98. When coupling
element 94 is moved within proximity to or contact with contaminant
75, coupling may occur between coupling element 94 and contaminant
75. The coupling mechanism that results is a function of the
materials, and properties thereof, from which coupling elements 94
and contaminant 75 are formed. Interaction between coupling element
94 and contaminant 75 is sufficient to allow the transfer of a
force of sufficient magnitude to overcome an adhesive force between
contaminant 75 and surface 98, as well as any repulsive forces
between coupling element 94 and contaminant 75. Thus, upon coupling
element 94 moving away from surface 98 by a shear force {right
arrow over (.tau.)} contaminant 75 that is coupled thereto is also
moved away from surface 98, i.e., contaminant 75 is cleaned from
surface 98.
[0041] One such coupling mechanism is mechanical contact between
coupling elements 94 and contaminant 75. To that end, coupling
elements 94 may be more or less malleable than contaminant 75. In
an embodiment wherein coupling elements 94 are more malleable than
contaminants 75, the force imparted upon contaminant 75 is reduced
due to deformation of coupling elements 94 occurring from impact
with contaminant 75. As a result, contaminant 75 may become
imprinted within coupling element 94 and/or entangled in a network
of coupling elements 94. This may produce a mechanical linkage
between coupling element 94 and contaminant 75, fixing the relative
position therebetween. Mechanical stresses may be transferred of
coupling elements 94 to contaminant 75, thereby increasing the
probability that contaminant 75 is broken free from surface 98.
Additionally, a chemical coupling mechanism, such as adhesion
between contaminant 75 and coupling elements 94, may occur.
[0042] Where coupling elements 94 and contaminant 75 sufficiently
rigid, a substantially elastic collision would occur resulting in a
significant transfer of energy from coupling elements 94 to
contaminant 75, thereby increasing the probability that contaminant
75 is broken free from surface 98. However, the chemical coupling
mechanism of adhesion between coupling elements 94 and contaminant
75 may be attenuated, which may reduce the probability gained by
the collision.
[0043] In addition, to mechanical and chemical coupling mechanisms
discussed above, electrostatic coupling may occur. For example,
were coupling element 94 and contaminant 75 to have opposite
surface charges they will be electrically attracted. It is possible
that the electrostatic attraction between coupling element 94 and
contaminant 75 can be sufficient to overcome force connecting
contaminant 75 to surface 98. It should be realized that one or
more the aforementioned coupling mechanisms may be occurring at any
given time with respect to one or more contaminants 75 on surface.
In addition, this may occur randomly or be induced by having
coupling element 94 formed from different materials and having
different shape and hardness. Alternatively, the electrostatic
repulsive interaction between the approaching coupling element 94
and the contaminant 75 may be strong enough to dislodge the
contaminant 75 from the surface 98.
[0044] Referring to FIGS. 2, 4 and 7, interaction of coupling
elements 94 with contaminant 75 is achieved, in part, by generating
relative movement between substrates 64 and solution 71. Relative
movement between suspension 90 and substrate 64 occurs at a rate to
impart sufficient momentum to allow coupling elements 94 to impact
with contaminants 75 and impart a sufficient drag force {right
arrow over (F)}.sub.D to move contaminant from surface 98 of
substrate 64, as discussed above. In one embodiment of the present
invention, relative movement occurs by placing cassette 70 into
solution 71 at a requisite velocity to generate the momentum
discussed above and without causing so a quantity of momentum that
would damage features of substrate 64 should the same impact with
coupling elements 94. This occurs, in part, by filling immersion
tank 52 with solution 71 at function 200. At function 202, cassette
70, having a least one substrate 64 with contaminants 75 thereon,
is lowered into solution 71, generating relative movement between
solution 71 and substrate 64. In this manner, two spaced apart
flows 100 and 102 are created around substrate 64. As shown flow
100 is adjacent to a side of substrate 64 that is opposite to the
side to which flow 102 is adjacent. The direction of flows 100 and
102 is substantially transverse to a normal, N, to a surface of
substrate 64. Flow 100 and 102 each has coupling elements 94
entrained therein. The relative movement imparts sufficient drag
upon a subset of coupling elements 94 in each of flows 100 and 102
to interact with and cause contaminants 75 to move with respect to
the substrate 64 and be removed therefrom. Following a sufficient
amount of movement substrates may be removed from cassette 70 by
the manner discussed above at function 204. Following removal
substrate 64 may be rinsed to as to completely remove contaminants
remaining on substrate 64 by, for example, a de-ionized water (DIW)
rinse at function 206. Alternatively, solution 71 may be drained
vis-a-vis one of conduits 55. Thereafter, another one of conduits
55 may be employed for the introduction of DIW to rinse any
remaining contaminants from substrates 64.
[0045] Referring to both FIGS. 4 and 8, in another embodiment,
cassette 70 is lowered into immersion tank 52 in the absence of
solution 71. Specifically, cassette 70 is placed to rest upon shelf
93 that is supported upon closed 58 by supports 95. Thereafter,
solution 71 is introduced into immersion tank 52 by a showerhead
101. To that end, showerhead 101, in fluid communication with a
supply 103 of solution 71, is designed to produce a plurality of
flows of solution 71 having coupling elements 94 entrained therein.
Concurrently with ingress of solution 71 into immersion tank 52,
conduits 55 may function as drains to remove the same therefrom.
Showerhead 101 is configured to generate a curtain of solution 71,
which is flowed over opposed surface of each of substrates 64 for a
sufficient amount of time to remove contaminants 75 from the
surfaces thereof. In another embodiment of the present invention,
conduits 55 may be closed to allow solution 71 exiting showerhead
101 to accumulate in immersion tank 52 and allow substrate 64 to
become submerged in solution 71. This may be undertaken by coupling
of a pump system 106 to each of conduits 55 to control the flow
rate therethrough. Posts 95 may be configured to allow shelf to
reciprocating between position 105 and position 107. In this
manner, relative motion between solution 71 and opposed surfaces of
each of substrates 64 may occur along opposing directions.
[0046] Exemplary embodiments of suspension 90 includes a liquid
region 92 having a viscosity between about 1 Centipoises (cP) to
about 10,000 cP. Moreover, liquid regions 69 may be a Newtonian
fluid or a non-Newtonian fluid. Exemplary materials that may be
employed as liquid region 92 include de-ionized water (DIW),
hydrocarbon, a fluorocarbon, a mineral oil, or an alcohol and the
like. Furthermore, suspension 90 may include ionic or non-ionic
solvents and other chemical additives. For example, the chemical
additives to suspension 90 can include any combination of
co-solvents, pH modifiers, chelating agents, polar solvents,
surfactants, ammonia hydroxide, hydrogen peroxide, hydrofluoric
acid, tetramethylammonium hydroxide, and rheology modifiers such as
polymers, particulates, and polypeptides.
[0047] Coupling elements 94 may possess physical properties
representing essentially any sub-state such that in addition to the
properties set forth above, do not adhere to surface 98 when
positioned in close proximity or contact with surface 98.
Additionally, the damage caused to surface 98 by coupling elements
94 should be deminimus, as well as the adhesion between coupling
elements 94 and surface 98. In one embodiment, the hardness of
coupling elements 94 is less than the hardness of surface 98.
Moreover, it is desired that coupling element 94 avoiding adherence
to surface 98 when positioned in either close proximity to or in
contact with surface 98. Various embodiments coupling elements 94
may be defined as crystalline solids or non-crystalline solids.
Examples or non-crystalline solids include aliphatic acids,
carboxylic acids, paraffin, wax, polymers, polystyrene,
polypeptides, and other visco-elastic materials. To that end, the
quantity of coupling elements 94 in suspension 90 should be present
at a concentration that exceeds its solubility limit within liquid
region 92.
[0048] It should be understood that the aliphatic acids represent
essentially any acid defined by organic compounds in which carbon
atoms form open chains. A fatty acid is an example of an aliphatic
acid that can be used as coupling element 94 within suspension 90.
Examples of fatty acids that may be used include lauric, palmitic,
stearic, oleic, linoleic, linolenic, arachidonic, gadoleic, eurcic,
butyric, caproic, caprylic, myristic, margaric, behenic,
lignoseric, myristoleic, palmitoleic, nervanic, parinaric,
timnodonic, brassic, clupanodonic acid, lignoceric acid, cerotic
acid, and mixtures thereof, among others.
[0049] In one embodiment, coupling elements 94 may represent a
mixture of fatty acids formed from various carbon chain lengths
extending from C-1 to about C-26. Carboxylic acids are defined by
essentially any organic acid that includes one or more carboxyl
groups (COOH). When used as coupling elements 94, the carboxylic
acids can include mixtures of various carbon chain lengths
extending from C-1 through about C-100. Also, the carboxylic acids
can include other functional groups such as but not limited to
methyl, vinyl, alkyne, amide, primary amine, secondary amine,
tertiary amine, azo, nitrile, nitro, nitroso, pyridyl, carboxyl,
peroxy, aldehyde, ketone, primary imine, secondary imine, ether,
ester, halogen, isocyanate, isothiocyanate, phenyl, benzyl,
phosphodiester, sulfhydryl, but still maintaining insolubility in
suspension 90.
[0050] One manner by which to form suspension 90 with regions
formed from carboxylic acid components includes presenting liquid
regions 69 as a gel that is formed from a concentration of
carboxylic acid solids, such as between about 3% to about 50 wt %
and preferably between about 4% to about 20 wt %, with De-ionized
water (DIW). Ammonium hydroxide may be added to the solution and
the mixture heated to between 55.degree. C. to about 85.degree. C.,
inclusive to facilitate the solids going into solution, i.e.,
dissolving. Once the solids are dissolved, the cleaning solution
can be cooled down. During the cooling down process, solid
compounds in the form of needles or plates would precipitates. An
exemplary suspension 90 formed in this manner has a viscosity of
about 1000 cP at 0.1 per second shear rate and the viscosity falls
to about 10 cP when the shear rate increases to 1000 per second,
i.e., it is a non-Newtonian fluid. It should be understood that
suspension may be formed by carboxylic acid(s) (or salts) in
solvents other than water, polar or non-polar solvents, such as
alcohol, may be employed.
[0051] Another embodiment of suspension 90 has coupling elements 94
are formed from a hydrolyzed chemical agent, or by including a
surfactant. For example, a dispersant material may be included in
liquid region 92 to facilitate dispersal of coupling element 94
throughout suspension 90. To that end, a base can be added to
suspension 90 to enable entrainment of coupling elements 94 from
materials such as carboxylic acid or stearic acid that are present
in less than stoichiometric quantities. An exemplary base is
Ammonium Hydroxide, however, any commercially available base may be
used with the embodiments described herein. Additionally, the
surface functionality of the materials from which coupling elements
94 are formed may be influenced by the inclusion of moieties that
are miscible within suspension 90, such as carboxylate, phosphate,
sulfate groups, polyol groups, ethylene oxide, etc. In this manner,
it may be possible to disperse coupling elements 94 throughout
suspension 90 while avoiding unwanted agglomeration of the same,
i.e., form a substantially homogenous suspension 90. In this
manner, avoided may be a situation in which an agglomeration of
coupling elements 94 becomes insufficient to couple to and/or
remove contaminant 96 from surface 98.
[0052] Referring to FIG. 9, in another alternate embodiment,
suspension 190 may include an additional component, referred to as
an immiscible component 111 that is entrained in liquid region 192.
Immiscible components include may include a gas phase, a liquid
phase, a solid phase of material, or a combination thereof. In the
present example, immiscible components 111 are regions comprising
entirely of a plurality of spaced-apart gas pockets dispersed
throughout liquid region 192 of suspension 190. The immiscible
components comprise from 2% to 99%, inclusive suspension 190 by
volume. Exemplary gas phase immiscible components 111 may be formed
from the following gases: nitrogen, N.sub.2, argon, Ar, oxygen,
O.sub.2, ozone, O.sub.3, peroxide, H.sub.2O.sub.2, air, hydrogen,
H.sub.2, ammonium, NH.sub.3, hydrofluoric acid, HF.
[0053] Liquid phase immiscible components 111 may include a
low-molecular weight alkane, such as, pentane, hexane, heptane,
octane, nonane, decane, or mineral oil. Alternatively, liquid phase
immiscible components 111 may include oil soluble surface
modifiers. Referring to both FIGS. 4 and 9, suspension 190
functions substantially similar to suspension 90 with respect to
removing contaminant 75, with coupling elements 94 being
substantially similar to coupling elements 94 and liquid region 192
being substantially similar to liquid region 92. In suspension 190,
however, immiscible component 111 is believed to facilitate placing
coupling elements 194 in contact with, or close proximity to,
contaminant 75. To that end, one or more of regions in close
proximity to, or contact with contaminant 75, is disposed between
contaminant 75 and one or more immiscible components 111. Having a
surface tension associated therewith, immiscible component 111
subjects coupling elements 194 to a force (F) on coupling element
194 in response to forces in liquid region 192. The force (F) moves
coupling element 194 toward surface 98 and, therefore, contaminant
75. Coupling between coupling element 194 and contaminant 75 may
occur in any manner discussed above with respect to coupling
elements 94 and contaminant 75.
[0054] Immiscible components 111 may be entrained in suspension 190
before being disposed on substrate 64. Alternatively, immiscible
components 111 may be entrained in suspension 190 in-situ as
suspension is being deposited on surface 98 and/or may be generated
by impact of suspension 190 with surface 98 thereby entraining
gases, such as air, present in the surrounding ambient, e.g.,
generating a foam. In one example, immiscible components 111 may be
generated from a gas dissolved within liquid region 192 that comes
out of solution upon suspension 190 being subjected to a decrease
in ambient pressure relative to pressure of suspension 190. On
advantage of this process is that the majority of immiscible
components 111 will form proximate to coupling elements 194, due to
coupling elements 194 have moved settled under force gravity toward
surface 98. This increases the probability that coupling elements
194 coupling with contaminant 75.
[0055] As with bi-state suspension 90, tri-state suspension 190 may
include additional components to modify and improve the coupling
mechanism between coupling elements 194 and contaminant. For
example, the pH of the liquid medium can be modified to cancel
surface charges on one or both of the solid component and
contaminant such that electrostatic repulsion is reduced or
amplified. Additionally, the temperature cycling of suspension 190
may be employed to control, or change, the properties thereof. For
example, coupling elements 94 may be formed from a material, the
malleability of which may change proportionally or inversely
proportionally with temperature. In this fashion, once coupling
elements 94 conform to a shape of contaminant, the temperature of
suspension may be changed to reduce the malleability thereof.
Additionally, the solubility of suspension 190 and, therefore, the
concentration of coupling elements 94 may vary proportionally or
inversely proportionally with temperature.
[0056] An exemplary suspension 190 is fabricated by combining
Stearic acid solids, heated above 70.degree. Celsius, to DIW heated
above 70.degree. Celsius. The quantity of Stearic acid solids
combined with the DIW is approximately 0.1% to 10%, inclusive by
weight. This combination is sufficiently to disperse/emulsify the
Stearic acid components within the DIW. The pH level of the
combination is adjusted above 9 to neutralize the stearic acid
components. This is achieved by adding a base, such as ammonium
hydroxide (NH.sub.4OH) to provide a concentration of 0.25% and 10%,
inclusive by weight. In this manner, an acid-base mixture is
formed, which is stirred for 20 minutes to ensure the homogeneity
of the mixture. The acid-base mixture is allowed to reach ambient
temperature allowing the fatty acid salt to precipitate and form
coupling elements 194. It is desired that coupling elements 194
formed during precipitation reach a size in a range of 0.5 to 5000
micrometers, inclusive. Immiscible component 111 may be formed from
entrainment of air within the acid-base mixture as the same is
stirred, if desired.
[0057] In another embodiment, suspension 190 is formed by from
granular Stearic acid solids milled to a particle size in a range
of 0.5 to 5000 micrometers, inclusive. The milled Stearic acid in
granular form is added to DIW while agitating the same to form an
acid-DIW mixture. Agitation of the DIW may occur by any means
known, such as shaking, stirring, rotating and the like. The
Stearic acid forms approximately 0.1% to 10%, inclusive, by weight
of the acid-DIW mixture. Dissociation of the Stearic acid is
achieved by establishing the pH level of the acid-DIW mixture to be
approximately 9 by adding a base. An exemplary base includes
ammonium hydroxide (NH.sub.4OH) in a concentration of 0.5% to 10%,
inclusive by weight. The base neutralizes the Stearic acid
component forming ammonium stearate salt particles. Typically the
NH.sub.4OH is added to the acid-DIW mixture while the same is being
agitated to disperse the solidified Stearic acid particles
throughout the acid-DIW mixture. The size distribution of these
solidified ammonium stearate particles is in a range of 0.5 to
5,000 micrometers, inclusive.
[0058] In yet another embodiment, suspension 190 is formed from a
Stearic-palmitic acid mixture dissolved in isopropyl alcohol (IPA)
while the IPA is agitated, as discussed above. This provides a
concentration of dissolved fatty acids present in the concentration
from a range 2% to 20%, inclusive by weight. Heating of the IPA
while avoiding boiling of the same and/or adding an organic
solvent, such as acetone, benzene or a combination thereof, may
improve solubility of the fatty acid. Any solids remaining in the
concentration following dissolution may be removed by filtration or
centrifugation techniques, producing a solid-free solution. The
solid-free solution may be mixed with a liquid that is a
non-solvent, to the fatty acid, such as water, to precipitate a
fatty-acid solid. The precipitated fatty acid becomes suspended in
solution with the size distribution in the range between 0.5 and
5,000 microns, inclusive. The Stearic acid component may be
ionized, as discussed above.
[0059] Referring to FIG. 10 in accordance with another embodiment
of the present invention a substrate cleaning system 400 (SCS)
includes a plurality of immersion tanks, shown as 402, 404 and 406.
Each of immersion tanks 402, 404 and 406 may include any one of
suspensions mention above, e.g., suspension 90 or 190. A picker
system that includes multiple pickers, shown as 408, 410 and 412.
Each of pickers 408, 410 and 412 is coupled to reciprocate along a
track 414 so that a substrate 64 held by any one of pickers 408,
410 and 412 may be placed in any one of immersion tanks 402, 404
and 406. System 400 is operated under control of a processor 416,
which is in data communication with a computer-readable memory 418.
Processor 416 controls operation of system 400 to submerge
substrates 64 into immersion tanks 402, 404 and 406. To that end,
processor is in data communication with a motor 420 that functions
to move pickers 408, 410 and 412 along track 414, as well as move
substrate 64 into, and out of, immersion tanks 408, 410 and 412.
Processor is also in data communication with fluid supplies 422,
424 and 426 to regulate the introduction of fluids into immersion
tanks 408, 410 and 412. Additionally, processor 416 is in data
communication with immersion tanks 408, 410 and 412 to control the
operation thereof, e.g., to allow drainage of fluids from immersion
tanks 408, 410 and 412.
[0060] Referring to both FIGS. 10 and 11 in operation, one of
pickers 408, 410 and 412, shown as picker 408, deposits a substrate
64 into one of immersion tanks 402, 404 and 406, shown as being
immersion tank 402. While in immersion tank 402, substrate 64 rests
upon support 428. Immersion tank 402 is then filled with solution
71. Solution 71 is introduced into immersion tank 402 under
operation of processor 416, which facilitates pump (not shown) of
fluid supply 422 to move solution 71 from there along conduits 430
and into the appropriate immersion tank 402, 404 and 406. To
control flow into immersion tanks 402, 404 and 406, each of the
same includes a valve 432, 434 and 436, in data communication with,
and operated under control of, processor 416. Valve 432 selectively
allows and prevents fluid from progressing from fluid supplies 422,
424 and 426 to immersion tank 402; valve 434 selectively allows and
prevents fluid from progressing from fluid supplies 422, 424 and
426 to immersion tank 404; and valve 436 selectively allows and
prevents fluid from progressing from fluid supplies 422, 424 and
426 to immersion tank 406. Drainage from immersion tanks 402, 404
and 406 is regulated by processor 416 controlling pumps 438, 440
and 442, which is in data communication therewith. Specifically,
drainage of immersion tank 402 is facilitated or prevented by pump
438; drainage of immersion tank 404 is facilitated or prevented by
pump 440; and drainage of immersion tank 406 is facilitated or
prevented by pump 442.
[0061] During one mode of operation, solution 71 is introduced into
immersion tank 402 at outlet 446 to fill upon immersion tank 402.
This may be achieved before or after introducing substrate 62 into
immersion tank 402. Typically, however, substrate 64 is position in
immersion tank 402 before introduction of solution 71. After
resting again support 428, processor 416 introduces solution 71
into immersion tank 402. As solution 71 is introduced through
outlet 446, processor 416 activates pump 438 to evacuate solution
71 from immersion tank 402. In this manner, substrate 64 is exposed
to a continuous flow of solution 71. It should be noted that each
of immersion tanks 402, 404 and 406 may employed concurrently to
expose substrate 64 to a continuous flow of solution 71. To that
end, valves 432, 434 and 436 would be operated to allow the ingress
of solution 71, from one of supplies 422, 424 and 426 into
immersion tanks 420, 404 and 406. Alternatively, one or more of
immersion tanks 402, 404 and 406 may include DIW, supplied from one
of supplies 422, 424 and 426. After being exposed to solution 71,
substrate 564 would be rinsed by being exposed to DIW. This may be
accomplished by filling one of immersion tanks 420, 404 and 406
with DIW and then introducing substrate 64 therein. Alternatively,
substrate 64 may be present in one of immersion tanks, 420, 404 and
406, after which time DIW would be introduced into the same. As
well, one of immersion tanks 402, 404 and 406 may include
suspension 90 while one of the remaining immersion tanks 402, 404
and 406 may include suspension 190, with the remaining immersion
tanks 402, 404 and 406 would contain DIW. In this configuration,
substrate 64 would be exposed to both suspensions 90 and 190 before
being rinsed with DIW. It is feasible to sequentially expose
substrate 64 suspensions 90 and 190 and DIW sequentially in a
common immersion tank 402. If desired, immersion tanks 402, 404 and
406 may be sealed after substrate 64 is placed therein, shown by
cover 450 sealing immersion tank 406 including a throughway 52 that
may be connected to a purge gas supply 454, such as helium. In this
manner immersion tank 406 may be environmentally controlled to
reduce, if not avoid, premature drying of substrate 84. An O-ring
is employed to form a hermetically-tight seal between cover 450 and
immersion tank 406.
[0062] Referring to both FIGS. 10 and 12, another embodiment of
immersion tanks 402, 404 and 406 is shown as immersion tank 502
having a lid 503 with an o-ring 505 forming a fluid tight seal with
body 507 of immersion tank 502. Specifically, immersion tank
includes a plurality of throughways 540, 542, 544, 546, 547, 548,
550 and 552. Throughways 540 and 548 are selectively placed in
fluid communication with a supply of isopropyl alcohol (IPA) and
DIW, and throughways 546 and 552 are selectively placed in fluid
communication with a supply of cleaning solution and DIW.
Specifically, throughway 540 may be selectively placed in fluid
communication with IPA supply 554 and DIW supply 556 vis-a-vis
valves 558 and 560, respectively. Throughway 548 may be selectively
placed in fluid communication with IPA supply 562 and DIW supply
564 vis-a-vis valves 566 and 568, respectively. Throughways 542 and
550 are in fluid communication with drains 570 and 572,
respectively. Throughway 546 may be selectively placed in fluid
communication with a supply 574 of cleaning solution 71 and DIW
supply 576 vis-a-vis valves 580 and 582, respectively. Throughway
547 may be selectively placed in fluid communication with drain 549
vis-a-vis a valve 551. Throughway 552 may be selectively placed in
fluid communication with a supply 584 of cleaning solution 71 and
DIW supply 586 vis-a-vis valves 588 and 590, respectively.
[0063] In operation, substrate 64 is placed in immersion tank 502
in the absence of solution 71. One or both of valves 580 and 588
are activated, under control of processor 416 to generate a flow of
solution into immersion tank 502 through throughways 546 and 552,
respectively. As a result, flows 600 and 602 of solution 71 are
generated that move in a direction opposite to gravity {right arrow
over (g)}; so as to pass adjacent to opposed surfaces 65 and 67 of
substrate 64, with solution exiting immersion tank 502 by passing
into throughways 542 and 550 onto drains 570 and 572, respectively.
After exposure to a sufficient quantity of solution 71 surfaces 65
and 67 are rinsed by exposure to one or more of IPA and/or DIW. To
that end, valves 580 and 588 are deactivated and valves 582 and 590
are activated. In this fashion, substrate 64 is exposed to DIW from
supplies 576 and 586, with the DIW passing into drains 570 and 572.
Alternatively, valves 551, 560 and 568 may be activated to allow
flows 610 and 612 of DIW along a path in the direction of gravity
{right arrow over (g)} and exit to drain 549 This is undertaken in
the absence of a vacuum. After substrate 64 is completely submerged
with DIW, pump 570 is activated to remove DIW. In a similar manner,
substrate 64 may be rinsed with IPA from supplies by activation of
valves 558 and 566.
[0064] Referring to FIGS. 12 and 13, in accordance with another
embodiment of the present invention, another embodiment of
immersion tank 502 is shown as immersion tank 602 in which a body
607 throughways, 642, 644, 646, 647, 650, 652, drains 649, 670,
672, supplies 674, 676, 684, 686 and valves 680, 682, 688 and 649
provide the same functions provided by body 507 throughways 542,
544, 546, 547, 550 and 552, drains 570, 572, supplies 574, 576,
584, 586 and valves 580, 582, 588 and 549, respectively. In
addition, immersion tank 602 has formed into body 607 two
additional throughways 691 and 692 that allow access to immersion
tank by IPA from supply 654 and 662, respectively. Specifically,
valve 658 allows selectively access of IPA from supply 654 to
immersion tank 602, valve 666 allows selectively access of IPA from
supply 662 to immersion tank 602. Valve 660 allows selectively
access of DIW from supply 656 to immersion tank 602, and valve 668
allows selectively access of DIW from supply 664 to immersion tank
602. In addition, a support 693 upon which substrate 64 rests is
coupled to a motor 694 to allow varying a distance between
substrate 64 and throughway 647. Lid 603 includes two sets of
O-rings 605 and 606. O-ring 605 functions in the manner as O-ring
605. O-ring 606, on the other hand is positioned at an end of a
stopper portion 695 of lid 603 positioned between throughways 540,
548 and throughways 542 and 550. In this configuration, throughways
691, 692, 640 and 648 are isolated from fluid flow exiting
throughways 546 and 552 when valve 551 prevents flow to drain 549,
i.e., a fluid-tight seal if formed between both throughways 642 and
650 and the throughways 691, 692, 640 and 648.
[0065] Referring to FIG. 13, in one manner of operation, substrate
64 is present placed in immersion tank 602 in the absence of
solution 71. One or both of valves 680 and 688 are activated, under
control of processor 416 to generate a flow of solution into
immersion tank 602 through throughways 646 and 652, respectively.
valve 551 is deactivated to prevent flow of solution 71 into drain
549. As a result, flows 700 and 702 of solution 71 are generated
that move in a direction opposite to gravity {right arrow over (g)}
so as to pass adjacent to opposed surfaces 65 and 67 of substrate
64, with solution exiting immersion tank 602 by passing into
throughways 642 and 650 onto drains 670 and 672, respectively.
[0066] Referring to both FIGS. 13 and 14, after exposure to a
sufficient quantity of solution 71 surfaces 65 and 67 are rinsed by
exposure to one or more of IPA and/or DIW. Specifically lid 601 is
removed to place expose throughways 691, 692, 540 and 548 in fluid
communication with throughways 542 and 550. Valves 658 and 666 are
activated to generate a flow of IPA under force of gravity {right
arrow over (g)} that results in the formation of a meniscus 700
where solution 71 contacts IPA and air in immersion tank 602.
During the flow of IPA from both throughways 691 and 692 motor 694
operates to move holder 693 and lift substrate 64 out of immersion
tank 602. As a result, solution 71 is removed from substrate 64 as
the same exits immersion tank.
[0067] While this invention has been described in terms of several
embodiments, it will be appreciated that those skilled in the art
upon reading the preceding specifications and studying the drawings
will realize various alterations, additions, permutations and
equivalents thereof. Therefore, it is intended that the present
invention includes all such alterations, additions, permutations,
and equivalents as fall within the true spirit and scope of the
invention. In the claims, elements and/or steps do not imply any
particular order of operation, unless explicitly stated in the
claims.
[0068] In one embodiment, the memory stores computer-readable
instructions to be operated on by the processor, wherein the
computer-readable instructions include a first set of code to
control said carrier sub-system and place said substrate in the
tank and a second set of code to control the solution handling
sub-system.
[0069] In one embodiment, the computer-readable instructions
further include a first sub-routine to control said solution
handling system to terminate said spaced-apart flows and fill said
tank with said solution and a second sub-routine to control said
carrier sub-system to remove said substrate from said tank.
[0070] In one embodiment, the computer-readable instructions
further include a first sub-routine to control said solution
handling system to fill said tank with said solution.
[0071] In one embodiment, the computer-readable instructions
further include a sub-routine to fill said tank with a quantity of
said solution and terminate said spaced-apart flows.
* * * * *