U.S. patent application number 11/419131 was filed with the patent office on 2007-04-19 for system for processing a workpiece.
This patent application is currently assigned to Semitool, Inc.. Invention is credited to Kyle M. Hanson.
Application Number | 20070084829 11/419131 |
Document ID | / |
Family ID | 33459047 |
Filed Date | 2007-04-19 |
United States Patent
Application |
20070084829 |
Kind Code |
A1 |
Hanson; Kyle M. |
April 19, 2007 |
System for processing a workpiece
Abstract
A system for processing a workpiece includes a process head
assembly and a base assembly. The process head assembly has a
process head and an upper rotor. The base assembly has a base and a
lower rotor. The base and lower rotor have magnets wherein the
upper rotor is engageable with the lower rotor via a magnetic force
created by the magnets. The engaged upper and lower rotors form a
process chamber where a semiconductor wafer is positioned for
processing. Process fluids for treating the workpiece are
introduced into the process chamber, optionally while the
processing head spins the workpiece. Additionally, air flow around
and through the process chamber is managed to reduce particle
adders on the workpiece.
Inventors: |
Hanson; Kyle M.; (Kalispell,
MT) |
Correspondence
Address: |
PERKINS COIE LLP/SEMITOOL
PO BOX 1208
SEATTLE
WA
98111-1208
US
|
Assignee: |
Semitool, Inc.
Kalispell
MT
|
Family ID: |
33459047 |
Appl. No.: |
11/419131 |
Filed: |
May 18, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10867458 |
Jun 14, 2004 |
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11419131 |
May 18, 2006 |
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10690864 |
Oct 21, 2003 |
6930046 |
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11419131 |
May 18, 2006 |
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10202074 |
Jul 23, 2002 |
6794291 |
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11419131 |
May 18, 2006 |
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09437711 |
Nov 10, 1999 |
6423642 |
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11419131 |
May 18, 2006 |
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PCT/US99/05676 |
Mar 15, 1999 |
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11419131 |
May 18, 2006 |
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60116750 |
Jan 22, 1999 |
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Current U.S.
Class: |
216/92 |
Current CPC
Class: |
H01L 21/67017 20130101;
H01L 21/67173 20130101; H01L 21/68785 20130101; H01L 21/6715
20130101; H01L 21/32134 20130101; H01L 21/67028 20130101; H01L
21/6719 20130101 |
Class at
Publication: |
216/092 |
International
Class: |
C03C 15/00 20060101
C03C015/00 |
Claims
1. A method for processing a workpiece comprising the steps of:
placing the workpiece into a base assembly having a base and a
first rotor; applying a magnetic force to repel the first rotor
from the base; engaging a second rotor to the first rotor to form a
process chamber around the workpiece; forcing the engaged rotors
against the magnetic repulsion force to create engagement between
the first and second rotors; spinning the first and second rotors;
and applying a processing fluid to the workpiece.
2. The method of claim 1, wherein the step of applying a process
fluid to the workpiece comprises the steps of: applying a first
processing fluid to a first surface of the workpiece; and applying
a second processing fluid to a second surface of the workpiece.
3. The method of claim 1 further comprising the step of draining
the process fluid from the process chamber.
4. The method of claim 2, wherein the first process fluid comprises
a fluid selected from the group consisting of air, nitrogen,
isopropylalcohol, water, ozonated water, hydrofluoric acid,
sulfuric acid, hydrogen peroxide, and ST-250.
5. The method of claim 2, wherein the second process fluid
comprises a fluid selected from the group consisting of air, water,
ozonated water, nitrogen, isopropylalcohol, hydrofluoric acid,
sulfuric acid, hydrogen peroxide, and ST-250.
6. A method for processing a workpiece comprising the steps of:
placing the workpiece into a process vessel having an upper rotor
and a lower rotor; applying a magnetic force to one of either the
upper or lower rotors so that the upper rotor engages the lower
rotor to form a process chamber around the workpiece; spinning the
engaged first and second rotors and the workpiece; and applying a
process fluid to the workpiece.
7. The method of claim 6, wherein the upper and lower rotors
comprise a plurality of pins for containing the workpiece.
8. The method of claim 6 further comprising the step of venting
gaseous fluids from the process chamber.
9. The method of claim 8, wherein the step of venting gaseous
fluids from the process chamber comprises applying a vacuum to the
process chamber.
10. The method of claim 6 further comprising the step of draining
the process fluid from the process chamber.
11. The method of claim 6 further comprising the step of aligning
the workpiece in an x-y plane before applying a magnetic force to
one of either the upper or lower rotors.
12. The method of claim 6 further comprising the step of drawing
air into the process chamber
13. The method of claim 6, wherein the workpiece has a top side and
a backside and the step of applying a process fluid to the
workpiece comprises: applying a first process fluid to the top side
of the workpiece; and applying a second process fluid to the
backside of the workpiece.
14. The method of claim 13, wherein the first and second process
fluids comprises a fluid selected from the group consisting of air,
nitrogen, isopropylalcohol, water, ozonated water, hydrofluoric
acid, sulfuric acid, hydrogen peroxide and ST-250.
15. A method for processing a plurality of workpieces comprising
the steps of: providing a plurality of workpieces at an
input/output station; moving the plurality of workpieces from the
input/output station to a plurality of process stations, at least
one of the plurality of process stations having a workpiece
processor comprising a process head assembly having a process head
and an upper rotor, a base assembly having a base and a lower
rotor, the base having a first magnet and the lower rotor having a
second magnet; placing the plurality of workpieces into the at
least one workpiece processor a single workpiece at a time;
applying a magnetic force to repel the lower rotor from the base
such that the lower rotor engages the upper rotor with the single
workpiece positioned between the lower and upper rotors; spinning
the rotors and the single workpiece; applying a process fluid to
the single workpiece; removing the single workpiece from the at
least one process station; and returning the processed workpieces
to the input/output station.
16. The method of claim 15, wherein a process is carried out on the
workpieces at each of the plurality of process stations and the
process is one selected from a group consisting of electrochemical
processing, etching, rinsing and drying.
17. The method of claim 15, wherein a robot moves the plurality of
workpieces from the input/output station to the plurality of
process stations.
18. The method of claim 15, wherein the step of applying a process
fluid to the single workpiece comprises: applying a first process
fluid to a first surface of the single workpiece; and applying a
second process fluid to a second surface of the single
workpiece.
19. The method of claim 18, wherein the first process fluid is
different than the second process fluid.
20. The method of claim 15, wherein the step of applying a process
fluid to the single workpiece comprises: applying a chemical
etchant to the single workpiece; rinsing the single workpiece with
deionized water; and drying the single workpiece with heated
nitrogen.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This Application is a Division of Continuation-In-Part U.S.
patent application Ser. No. 10/867,458 filed Jun. 14, 2004, now
pending, which is a Continuation-In-Part of U.S. patent application
Ser. No. 10/690,864, filed Oct. 21, 2003 now U.S. Pat. No.
6,930,046, which is a Continuation-In-Part of U.S. patent
application Ser. No. 10/202,074, filed Jul. 23, 2002 now U.S. Pat.
No. 6,794,291, which is a Continuation of U.S. patent application
Ser. No. 09/437,711, filed Nov. 10, 1999, now U.S. Pat. No.
6,423,642, which is a Continuation-In-Part and U.S. National Phase
of International Patent Application No. PCT/US99/05676, filed Mar.
15, 1999, published in English and designating the United States,
and claiming priority to U.S. patent application Ser. No.
60/116,750, filed Jan. 22, 1999. Priority to these Applications is
claimed under 35 U.S.C. .sctn..sctn. 119, 120, 121 and/or 365. The
above-identified Applications are also incorporated herein by
reference.
TECHNICAL FIELD
[0002] The invention relates to surface preparation, cleaning,
rinsing and drying of workpieces, such as semiconductor wafers,
flat panel displays, rigid disk or optical media, thin film heads
or other workpieces formed from a substrate on which
microelectronic circuits, data storage elements or layers, or
micro-mechanical elements may be formed. These and similar articles
are collectively referred to herein as a "wafer" or "workpiece."
Specifically, the present invention relates to a workpiece
processor and system for treating semiconductor workpieces.
BACKGROUND OF THE INVENTION
[0003] The semiconductor manufacturing industry is constantly
seeking to improve the processes and machines used to manufacture
microelectronic circuits and components, such as the manufacture of
integrated circuits from wafers. The objectives of many of these
improved processes and machines include: decreasing the amount of
time required to process a wafer to form the desired integrated
circuits; increasing the yield of usable integrated circuits per
wafer by, for example, decreasing contamination of the wafer during
processing; reducing the number of steps required to create the
desired integrated circuits; improving the uniformity and
efficiency of processes used to create the desired integrated
circuits; and reducing the costs of manufacture.
[0004] As the semiconductor industry advances particle "adder"
specifications, the number and size of the permitted particulate
contamination in the manufacture of semiconductor wafers is
continuously being reduced. Existing machines are not sufficient
for future particle specifications.
[0005] Further, in the processing of wafers, it is often necessary
to subject one or more sides of the wafer to a fluid in liquid,
vapor or gaseous form. Such fluids are used to, for example, etch
the wafer surface, clean the wafer surface, dry the wafer surface,
passivate the wafer surface, deposit films on the wafer surface,
remove films or masking materials from the wafer surface, etc.
Controlling how the processing fluids are applied to the wafer
surfaces, reducing the potential for cross contamination of the
processing fluids, and effectively cleaning or rinsing process
fluids from process chamber surfaces are often important to the
success of the processing operations.
SUMMARY OF THE INVENTION
[0006] A new wafer processing system has been invented that
provides significant improvements in manufacturing microelectronic
and similar devices. The new system reduces particle contamination.
As a result there are fewer defects in the end products. This
reduces the total amount of raw materials, process fluids, time,
labor and effort required to manufacture microelectronic devices.
Accordingly, the new wafer processing system of the present
invention significantly increases manufacturing yields.
[0007] A unique workpiece processor design has been invented that
significantly reduces cross contamination of process fluids. The
unique design also greatly increases the ability to exhaust vapor
or fumes and drain process fluids from the process chamber during
processing of a semiconductor wafer. Further, the processor of the
present invention utilizes a relatively simple, magnetic rotor
engagement mechanism that reduces variability of vibration affects
caused by variations in manufacturing techniques from one processor
to another. As a result of these design improvements, the effects
of wafer processing is more consistent from one workpiece processor
to the next, and high manufacturing quality standards and increased
efficiencies are achieved.
[0008] In one embodiment, the wafer processing system of the
present invention provides a plurality of workpiece stations for
plating, etching, cleaning, passivating, depositing and/or removing
films and masking materials from a workpiece surface. The system
includes a robot, which is moveable between the workpiece stations
and moves the workpiece from one station to another. At least one
of the workpiece stations includes a workpiece processor having an
upper rotor and a lower rotor engageable to form a workpiece
process chamber. A magnetic force between repulsing magnets is
utilized to maintain contact between the rotors during operation of
the processor. This unique process chamber design reduces
vibrations, which have been found to be a major contributor to
particulate contamination, and also reduces the chances of process
fluids leaking onto the surface of processed wafers, which can
result in defects or failure of the microelectronic end
products.
[0009] The wafer processing system of the present invention has
also been designed to increase air flow through the workpiece
processor during processing. Better air flow management reduces
particle contamination and increases overall processing efficiency.
As a result, less time, materials and energy is consumed.
Particularly, the processor of the present invention has air flow
passageways in the process head, which draws ambient air from the
mini-environment surrounding the processor, into the process head,
and out through the bottom of the processor. Further, annular
channels formed in the base and the upper rim of the base relieve
pressure build up in the process chamber. During operation,
openings in the upper rim of the base receive "blow-by" fluids. The
annular channels bleed the "blow-by" fluids off to an exhaust port,
relieving pressure build up. Moreover, an air aspirator is
connected to an annulus positioned below the motor in the process
head. The aspirator sucks any gaseous fluids that may come from the
air flow passageways in the process head or the annular channels in
the base. Additionally, a central opening in the process head and
upper rotor, and a process fluid nozzle in the base which extends
upwardly through an opening in the lower rotor and is connected to
a snorkel permits air to be drawn directly into the workpiece
processor during operation. As a result of these design
improvements, air flow in the process chamber is greatly enhanced,
and more uniform processing and increased efficiencies are
achieved.
[0010] Other features and advantages of the invention will appear
hereinafter. The features of the invention described above can be
used separately or together, or in various combinations of one or
more of them, with no single feature essential to the invention.
The invention resides as well in sub-combinations of the features
described. The process chamber can be used alone, or in a system
with robotic automation and various other process chambers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a perspective view of a workpiece processing
system according to the present invention.
[0012] FIG. 2 is a top plan view of the workpiece processing system
shown in FIG. 1, with components removed for purpose of
illustration.
[0013] FIG. 3 is a perspective view of a workpiece processor
according to one embodiment of the present invention.
[0014] FIG. 4 is a top view of the workpiece process chamber shown
in FIG. 3.
[0015] FIG. 5 is a cross-sectional view of the workpiece processor
shown in FIG. 4 taken along dashed line A-A.
[0016] FIG. 6 is a cross-sectional view of the workpiece processor
shown in FIG. 4 taken along dashed line B-B.
[0017] FIG. 7 is a cross-sectional view of the workpiece processor
shown in FIG. 4 taken along dashed line C-C.
[0018] FIG. 7A is an enlarged partial view of the area of the
processor designated A in FIG. 7.
[0019] FIG. 8 is a perspective view of a process head assembly
according to the present invention.
[0020] FIG. 9 is a top view of the process head assembly shown in
FIG. 8.
[0021] FIG. 10 is a cross-sectional view of the process head
assembly shown in FIG. 9 taken along dashed line A-A.
[0022] FIG. 11 is a perspective view of a bottom portion of a
process head assembly according to the present invention.
[0023] FIG. 12 is a perspective view of a top portion of a base
assembly according to the present invention.
[0024] FIG. 13 is a top view of the base assembly shown in FIG.
12.
[0025] FIG. 14 is a cross-sectional view of the base assembly shown
in FIG. 13 taken along dashed line A-A.
[0026] FIG. 15 is a cross-sectional view of the base assembly shown
in FIG. 13 taken along dashed line B-B.
[0027] FIG. 16 is a cross-sectional view of the base assembly shown
in FIG. 13 taken along dashed line C-C.
[0028] FIG. 17A is a top perspective view of an upper rotor
according to one embodiment of the present invention.
[0029] FIG. 17B is a cross-sectional view of the upper rotor
illustrated in FIG. 17A.
[0030] FIG. 17C is a bottom perspective view of the upper rotor
illustrated in FIGS. 17A and 17B.
[0031] FIG. 18A is a top perspective view of a lower rotor
according to one embodiment of the present invention.
[0032] FIG. 18B is a cross-sectional view of the lower rotor
illustrated in FIG. 18A.
[0033] FIG. 18C is a bottom perspective view of the lower rotor
illustrated in FIGS. 18A and 18B.
[0034] FIG. 19A is a top perspective view of an upper rotor
according to another embodiment of the present invention.
[0035] FIG. 19B is a cross-sectional view of the upper rotor
illustrated in FIG. 19A.
[0036] FIG. 19C is a bottom perspective view of the upper rotor
illustrated in FIGS. 19A and 19B.
[0037] FIG. 20A is a top perspective view of a lower rotor
according to another embodiment of the present invention.
[0038] FIG. 20B is a cross-sectional view of the lower rotor
illustrated in FIG. 20A.
[0039] FIG. 20C is a bottom perspective view of the lower rotor
illustrated in FIGS. 20A and 20B.
[0040] FIG. 21A is a top perspective view of a head ring of a
process head assembly according to the present invention.
[0041] FIG. 21B is a cross-sectional view of the head ring
illustrated in FIG. 21A.
[0042] FIG. 21C is an enlarged partial view of the area of the head
ring designated A in FIG. 21B.
DETAILED DESCRIPTION
[0043] As shown in FIGS. 1-3, a processing system 10 has an
enclosure 15, a control/display 17, and an input/output station 19
and a plurality of processing stations 14. Workpieces 24 are
removed from carriers 21 at the input/output station 19 and
processed within the system 10.
[0044] The processing system 10 includes a support structure for a
plurality of processing stations 14 within the enclosure 15. At
least one processing station 14 includes a workpiece processor 16
and an actuator 13 for opening and closing processor 16. The
processor 16 of the present invention is designed to be utilized in
a processing system 10, for example, as disclosed in pending U.S.
patent application Ser. Nos. 60/476,786, filed Jun. 6, 2003, Ser.
No. 10/691,688, filed Oct. 22, 2003 and Ser. No. 10/690,864, filed
Oct. 21, 2003. These U.S. patent applications are incorporated
herein by reference. System 10 may include only a plurality of
processors 16 or it may include other processing modules, in
addition to one or more processors 16, such as could be configured
to perform a variety of functions including but not limited to
electrochemical processing, etching, rinsing, and/or drying.
[0045] The system 10 in FIG. 2 is shown having ten process stations
14, but any desired number of processing stations 14 may be
included in the enclosure 15. The processing station support
preferably includes a centrally located, longitudinally oriented
platform 18 between the processing stations 14. One or more robots
26 having one or more end-effectors 31 move within the enclosure 15
for delivering workpieces 24 to and from various processing
stations 14, and to load and unload workpieces 24 into and out of
the process stations 14. In a preferred embodiment, the robot 26
moves linearly along a track 23 in the space 18. A process fluid
source and associated fluid supply conduits may be provided within
enclosure 15 below the platform 18 in fluid communication with a
workpiece processor 16 (shown in FIG. 3) and other processing
stations 14.
[0046] FIGS. 3-11 illustrate a workpiece processor 16 according to
the present invention. The processor 16 comprises a process head
assembly 28 and a base assembly 30. The head assembly 28 is
comprised of a process head 29, a head ring 33, an upper rotor 34,
a fluid applicator 32 and a motor 38. The base assembly 30 is
comprised of a mounting base 40, a lower rotor 36 and a bowl mount
43. The head assembly 28 can be moved vertically to engage with and
separate from the base assembly 30. The head assembly 28 and the
base assembly 30 form a process chamber 37 within which the upper
34 and lower 36 rotors are positioned.
[0047] Turning specifically to FIGS. 5-11, a process fluid
applicator 32 extends upwardly from a central portion of the head
assembly 28 and extends downwardly through a sleeve 96 into the
head assembly. Air inlet 140 and process fluid inlets 92, 94 are
positioned within the sleeve 96. The air inlet 140 and the process
fluid applicator 32 run downwardly through central openings in the
process head 29, the head ring 33 and the upper rotor 34. Process
fluid supply lines (not shown) are connected to the upwardly
extending portion of the process fluid applicator 32 for delivering
process fluids into the workpiece process chamber. The motor 38 is
positioned in the head 29 and is coupled to the upper rotor 34.
During operation, the motor 38 spins the upper rotor 34. The head
ring 33 mounts the upper rotor 34 and the motor 38 within the head
29. An automated actuator 13 is attached to the head assembly 28
and moves the process head assembly 28 from an open position, where
a workpiece may be loaded into and removed from the process chamber
37 by robot 26, to a closed position where the workpiece will be
processed. As will be explained more fully below, the head assembly
28 has a plurality of air inlets and passageways that contribute to
the improved air flow management of the present invention.
[0048] The base assembly 30 lower rotor 36 has an engagement ring
110 with three tabs 114 which cooperate with a slotted mounting
member 144 positioned at the bottom of the base 40 to attach the
lower rotor 36 to the base 40. The tabs 114 of the engagement ring
110 cooperate with the slots of the mounting member 144 to create a
bayonet connection. Positioned within the base 40 is at least a
first annular magnet 42. The lower rotor 36 also includes at least
one second magnet 44. It should be understood, that instead of
using single annular magnets in the base 40 and lower rotor 36 a
plurality of non-annular magnets may also be used. The first 42 and
second 44 magnets are adjacent to one another and have a like
polarity. By utilizing magnets having a like magnetic field or
polarity, the first 42 and second 44 magnets repel one another,
causing the lower rotor 36 to be forced upwards from the base 40 by
a magnetic force. When the head and base assemblies 28 and 30 are
separated, the magnetic force of the magnets 42, 44 pushes the
lower rotor 36 away from base 40 causing the tabs 114 of the
engagement ring 110 to firmly engage the mounting member 144 of the
base, thus providing the desired bayonet connection.
[0049] When the head and base assemblies are to be engaged, the
actuator 13 lowers the head assembly 28 until the upper rotor 34
contacts the lower rotor 36. Upon further force from the actuator
13, the upper rotor 34 pushes down on the lower rotor 36 and
against the repulsion force created by the magnets 42, 44 until the
head ring 33 seats on the base as shown in FIG. 7A at 33A. When the
head ring 33 seats on the base, the contact between the tabs 114 of
the engagement ring 110 and the mounting member 144 is broken, and
the lower rotor 36 is free to spin with the upper rotor 34. With
the head ring 33 and base 40 in the positions shown in FIGS. 5-7A,
with the lower rotor free to spin with the upper rotor, the
replusion force created by the magnets 42,44 maintains the contact
between the upper and lower rotors until the head assembly is
raised for loading/unloading the processor.
[0050] Turning to FIGS. 5-7 and 12-16, the base 40 includes an
annular plenum 80 which has several (e.g., four) drains 82. The
drains 82 are pneumatically actuated via a poppet valve 84 and
actuator 86. Each drain 82 is provided with a fitting connector 88
to provide separate paths for conducting processing liquids of
different types to appropriate systems (not shown) for storage,
disposal, or recirculation. Accordingly, cross contamination of
process fluids is minimized. As best shown in FIGS. 5-7, 18A-C and
20A-C, the lower rotor 36 has a skirt 48, which extends downwardly
into annular plenum 80 and encourages process fluids to flow into
annular plenum 80 and through the drains 82.
[0051] Still referring to FIGS. 5-7, 18A-C and 20A-C, the lower
rotor 36 has a plurality of pins extending upwardly from its
surface. First, the lower rotor 36 includes a plurality of
stand-off pins 50. When the workpiece 24 is loaded into the process
chamber 37, the workpiece 24 initially sits on the stand-off pins
50. The lower rotor 36 also includes a plurality of alignment pins
52, which align and center the workpiece 24 in the x-y plane when
the workpiece 24 is loaded into the process chamber 37. The
alignment pins 52 extend farther away from the surface 150 of the
lower rotor 36 than the stand-off pins 50 do, preventing the
workpiece 24 from being misaligned in the process chamber 16.
Finally, the lower rotor 36 includes at least one, and preferably a
plurality of engagement pins 54. The engagement pins 54 preferably
having a beveled end to enhance coupling with the upper rotor 34
(as explained below) and an annular gasket or O-ring 56 formed from
a compressible material to create a flexible contact with the upper
rotor 34.
[0052] Turning to FIGS. 5-7, 17A-C and 19A-C, the upper rotor 34
includes a plurality of stand-off pins 120 and countersunk bores
46. During operation, and best shown in FIGS. 5-7, the workpiece 24
(not shown) is contained between the stand-off pins 120 of the
upper rotor 34 and the stand-off pins 50 of the lower rotor 36.
Workpiece process chamber 37 is formed between the inner surface
148 of the upper rotor 34 and an inner surface 150 of the lower
rotor 36. The stand-off pins 50, 120 do not clamp the workpiece 24
between them, but instead contain the workpiece within a desired
clearance, allowing the workpiece 24 to slightly "clock," i.e.,
float within the desired clearance, during processing. This
prevents the workpiece 24 from being pinched and accidentally
damaged and allows a greater surface area of the workpiece 24 to be
treated. In a preferred embodiment, there is a 0.02 inch clearance
between stand-off pins 50, 120, which permits the workpiece 24 to
be "clocked" during processing. This arrangement allows
substantially the entire surface of the workpiece 24 to be treated,
even the surface area which would otherwise be covered by the
stand-off pins 50, 120.
[0053] Referring specifically to FIG. 5, as the upper rotor 34
engages the lower rotor 36, the beveled end of the engagement pins
54 are inserted into a corresponding one of the plurality of bores
46 (shown in FIG. 17C) in the upper rotor 34. The annular,
compressible gasket or O-ring 56 enhances contact between the upper
rotor 34 and the lower rotor 36 and acts as a vibration dampener
when the process chamber 16 is in use.
[0054] While the general configuration of the upper 34 and lower 36
rotors is as described above, the specific configuration may vary
depending on the desired process to be carried out in the process
chamber 16. For example, FIGS. 17A-C and 18A-C show the upper 34
and lower 36 rotors utilized in a process for removing polymer or a
masking material from a wafer surface. In this preferred
embodiment, the rotor configurations conform to the general
description provided above. As shown in FIGS. 17A-C, however, the
upper rotor 34 is segmented or provided with notches 160 to allow
process fluids to more freely exit the process chamber 37.
[0055] However, it may be preferred to employ slight variations to
the rotor configurations described above for a different process.
For example, the rotor configurations for a process commonly known
as "backside bevel etch" are disclosed in FIGS. 19A-C and 20A-C.
Generally, in a "backside bevel etch" process, a chemical solution
(e.g., hydrofluoric acid) is provided to etch, or selectively
remove, metal or oxide layers from the backside and/or peripheral
edge, i.e., the bevel edge, of the wafer. During this process,
while the backside and bevel are being supplied with the chemical
solution, the top side of the wafer is being supplied with an inert
gas or deionized water rinse, or an alternate processing solution.
After etching, the etched side and preferably both sides of the
wafer are supplied with deionized water rinse, spun to remove
fluids, and dried with heated nitrogen. A detailed explanation of
semiconductor etching processes, including the "backside bevel
etch" process is disclosed in U.S. Pat. No. 6,632,292, assigned to
the assignee of the present invention, and incorporated herein by
reference.
[0056] In a preferred embodiment, the upper rotor 34 utilized for a
"backside bevel etch" process is disclosed in FIGS. 19A-C. The
upper rotor 34 includes a process fluid passageway 108 that
communicates with an annulus 146 formed in the inner surface 148 of
the upper rotor 34. Turning to FIGS. 20A-C, the lower rotor 36
preferred for use in the "backside bevel etch" process includes a
sealing member 118 that runs circumferentially around the outer
perimeter of the lower rotor 36. Preferably, the sealing member 118
is formed from a compressible material. When the upper 34 and lower
36 rotors are engaged, the sealing member 118 deforms and creates a
contact face seal between the rotors. The contact face seal is not
a complete seal. That is, even with the contact face seal, "leaks"
are provided to allow draining of the process chamber 37. The
magnetic force from magnets 42, 44 keep the lower rotor 36 and
upper rotor 34 engaged and the contact seal in place during
processing. During the "backside bevel etch" process, the acidic
process fluid applied to the backside of the wafer wraps around the
periphery or bevel edge of the wafer onto a portion of the top side
of the wafer. As a result, the acidic process fluid is forced into
the annulus 146 formed in the inner surface 148 of the upper rotor
34 by the inert gas being applied to the top side of the wafer, and
is vented out through the process fluid passageway 108 in the upper
rotor 34.
[0057] Turning to FIGS. 21A-C, and as shown in FIG. 7A, the head
ring 33 includes a rim 162 and a vertical cylindrical alignment
surface 164. When the head assembly 28 and base assembly 30 are
closed, the vertical cylindrical alignment surface 164 aligns the
head ring 33 with the base 40 and rim 162 rests on the rim of the
base 40 to ensure proper alignment between the upper 34 and lower
36 rotors.
[0058] The improved air flow and process fluid drainage aspects of
the new wafer processing system will now be discussed.
[0059] First, the head assembly 28 has a multitude of air flow
passageways which draw ambient air from the fab environment into
the head assembly 28 and out through the base 40 of the process
chamber 16. As shown in FIG. 6, an annulus 136 is positioned in the
head 29 just below the motor 38. The annulus 136 is connected to an
air aspirator (not shown), Which sucks gaseous vapors or particles
from the motor 38 out of the head 29. An aspirator tube (not shown)
exits the head 29 via a service conduit attached to support 130.
The negative pressure created by the aspirator 132 also acts to
remove any gaseous vapors or fumes that may come from other air
passageways in the head assembly 28 or the base 40.
[0060] Second, turning to FIGS. 5-7 and 21A-C, a plurality of vents
holes 60 are formed in the head ring 33. As specifically shown in
FIGS. 21A-C, the vent holes 60 draw air from the mini-environment
within enclosure 15 through air channels 124 into an inner volume
or air gap 134 formed by the slanting outer surface of the upper
rotor 34 and the head ring 33. The inner air gap 134 communicates
with a channel 137 that wraps around the periphery of both the
upper rotor 34 and the lower rotor 36, and continues down into the
annular drain cavity 80 formed in the recess of the base 40.
Eventually, process fluid vapors are vented out through the exhaust
ports 82 formed in the annular drain cavity 80.
[0061] Third, the process chamber 16 of the present invention is
also designed to relieve inherent pressure build up experienced by
carrying out operations in a closed process chamber 16. Referring
to FIGS. 12-14, a plurality of openings 71 are formed in the upper
rim 73 of the base 40. The openings 71 are connected to exhaust
channels 142 formed in a lower portion of base 40. A pump or the
like (not shown) is connected to the exhaust channels 142 via at
least one, and preferably two, exhaust ports 72, creating a
negative pressure and a path for exhausting process fluids through
the channels 142 (represented by the dashed lines in FIG. 14).
Turning now to FIG. 5, when the head assembly 28 is lowered and
engages the base 40, an annular plenum 70 formed in the head ring
33 covers the upper rim 73 of the base 40. The annular plenum 70 in
the head ring 33 permits the openings 71 in the upper rim 73 to
receive "blow-by" of process fluids during operation. These
"blow-by" process fluids are bled off by the negative pressure in
the exhaust channels 142. Again, this process path is represented
by dashed lines in FIG. 5. Accordingly, unwanted pressure build up
in the process chamber 37 is minimized during operation.
[0062] Fourth, air is introduced directly into the workpiece
process chamber through openings in the head assembly 28 and the
base assembly 30. Turning to FIGS. 12-16, the base assembly 30
includes a centrally positioned process fluid applicator 62 that
extends upwardly from the base 40. Generally, the processing fluids
may be a liquid, vapor or gas or a combination of liquid/vapor/gas.
The process fluid applicator 62 in the base assembly 30 includes a
back-side vent aperture 64. In a preferred embodiment, process
fluid applicator 62 includes a plurality of back-side vent
apertures 64. The back-side vent apertures 64 communicate via air
channel 66 with snorkel 68. The snorkel 68 is open to the
mini-environment inside the enclosure 15, allowing air to be
delivered directly to the backside of the workpiece. Turning to the
head assembly 28 and FIGS. 3-7, an air inlet 140 is formed in a
central portion of the assembly 28. One end of the air inlet 140 is
open to the mini-environment and one end opens into the workpiece
process chamber through opening 106 in the upper rotor 34.
Accordingly, air is drawn from the mini-environment into the
workpiece process chamber to provide air directly to the top and
backsides of the workpiece.
[0063] During operation, process fluids are applied to the top and
backsides of the workpiece. The process fluid applicators of the
present invention will now be discussed in more detail. Both the
head assembly 28 and the base assembly 30 include process fluid
applicators. Referring to FIG. 13, the base assembly 30 has a
process fluid applicator 62 in the base 40. The applicator 62
includes a connector 74 for connecting the process fluid applicator
to a various process fluid supplies. Accordingly, the applicator 62
includes additional ports; e.g., lateral slotted port 76 and
apertures 78. The ports and apertures in the process fluid
applicator 62 direct process fluid upward through opening 112 in
the lower rotor 36 towards the backside workpiece surface. For
example, in a preferred embodiment, air is supplied through vent
apertures 64, an etchant (e.g., hydrofluoric acid, sulfuric acid,
or a mixed acid/oxidizer) is supplied through lateral slotted port
76, deionized water is supplied through a first aperture 78 and
nitrogen and isopropylalcohol are supplied through second aperture
78. The applicator 62 may also include a purging nozzle for
directing a stream of purging gas, such as nitrogen across the
workpiece surface.
[0064] With reference now to FIGS. 5-11, and as mentioned above,
the head assembly 28 also includes a process fluid applicator 32.
The applicator 32 has a nozzle 35 for directing streams of
processing fluids through inlets 92, 94 and out into the workpiece
process chamber through openings 100 in the head 29 and 106 in the
upper rotor 34, respectively. The processing fluids provided
through nozzle 35 and inlets 92, 94 may be the same or different
fluids. Examples of such processing fluids include air nitrogen,
isopropylalcohol, deionized water, hydrogen peroxide, ST-250 (a
post-ash residue remover solution), an etchant (e.g., hydrofluoric
acid, sulfuric acid), or any combination thereof. The nozzle 35 and
inlets 92, 94 extend axially downwardly through a sleeve 96 (that
includes air inlet 140) in the head 29 so as not to interfere with
rotation of the upper rotor 34, which is coupled to motor 38.
[0065] Operation of the new wafer processing system will now be
explained. With the process head assembly in an open position,
robot 26 loads a workpiece 24 into the process chamber 37 where it
sits on stand-off pins 50 extending from the lower rotor 36.
Actuator 13 begins to lower the head assembly 28 until it engages
base assembly 30. Axial centering extension 122 of the head ring 33
contacts the chamber assembly first, ensuring that head assembly 28
and the base assembly 30 are axially aligned. The head assembly 28
continues to move downward, until the upper rotor 34 makes contact
with the lower rotor 36. Eventually, the force applied to the lower
rotor 36 (from the actuator 13 via upper rotor 34) will overcome
the magnetic repulsion force between the magnets 42 in the base
bowl 40 and the magnets 44 in the lower rotor 36, relieving
engagement ring 110 (of the lower rotor 36) from the slotted
mounting member 144 (of the base 40). Engagement pins 54 of the
lower rotor 36 are inserted into the corresponding bores 46 in the
upper rotor 34. It may be necessary to rotate the rotors 34, 36
slightly in order to align the engagement pins 54 with the bores
46.
[0066] At this point in the operation of processor 16, the process
chamber 37 is in a fully-closed, process position. In this
position, the device or top side of the workpiece 24 and the inner
surface 148 of upper rotor 34 form a first process chamber 102. The
bottom side or backside of the workpiece 24 and the inner surface
150 of lower rotor 46 form a second process chamber 104. As
discussed above, fluid applicator 32 introduces process fluid to
the first process chamber 102, while fluid applicator 62 introduces
process fluid to the second process chamber 104. In a preferred
embodiment, the motor 38 rotates one of either the upper rotor 34
or the lower rotor 36. Because the rotors 34, 36 are engaged, the
workpiece 24 is spun while process fluids are applied to the top
and backsides of the workpiece 24. Liquids flow outwardly over the
workpiece 24 via centrifugal force. This coats the workpiece 24
with a relatively thin liquid layer. The tight tolerance between
the upper and lower rotors 34, 36 and the workpiece 24 helps to
provide a controlled and uniform liquid flow. Gases, if used, can
purge or confine vapors of the liquids, or provide chemical
treatment of the workpiece 24 as well. The spinning movement of the
rotors 34, 36 drives the fluids radially outward over the workpiece
24, and into the annular plenum 80 formed in the base 40. From
here, the process fluids exit the base 40 via drains 82. The valves
84 control release of the process fluids through fittings 88.
[0067] After processing is complete, the actuator 13 lifts the head
assembly 28 away from the base assembly 30 by actuating a motor. In
the system 10 shown in FIG. 2, the robot 26 moves along the track
23 and uses end-effector 31 to remove the workpiece 24 from the
open process chamber 16. The robot 26 then travels along the linear
track 23 for further processing of the workpiece 24, or to perform
a transport operation at the input/output station 19.
[0068] While the present invention has been described in terms of
concurrently providing different process fluids to the device and
bottom sides of the workpiece, multiple sequential processes of a
single workpiece can also be performed using two or more processing
fluids sequentially provided through a single inlet. For example, a
processing fluid, such as a process acid, may be supplied by the
lower process fluid applicator 62 to the lower process chamber 104
for processing the lower surface of the workpiece 24, while an
inert fluid, such as nitrogen gas, may be provided to the upper
process chamber 102. As such, the process acid is allowed to react
with the lower surface of the workpiece 24 while the upper surface
of the workpiece is effectively isolated from hydrofluoric acid
reactions.
[0069] While the process head, process head assembly, chamber
assembly, rotors, workpieces and other components are described as
having diameters, they can also have non-round shapes. Further, the
present invention has been illustrated with respect to a wafer or
workpiece. However, it will be recognized that the present
invention has a wider range of applicability. By way of example,
the present invention is applicable in the processing of flat panel
displays. microelectronic masks, and other devices requiring
effective and controlled wet chemical processing.
[0070] While embodiments and applications of the present invention
have been shown and described, it will be apparent to one skilled
in the art that other modifications are possible without departing
from the inventive concepts herein. The invention, therefore, is
not to be restricted except by the following claims and their
equivalents.
* * * * *