U.S. patent application number 11/081030 was filed with the patent office on 2005-07-21 for adaptable electrochemical processing chamber.
Invention is credited to Eudy, Steve L., Hanson, Kyle M., Harris, Randy, Weber, Curtis A., Woodruff, Daniel J..
Application Number | 20050155864 11/081030 |
Document ID | / |
Family ID | 43706155 |
Filed Date | 2005-07-21 |
United States Patent
Application |
20050155864 |
Kind Code |
A1 |
Woodruff, Daniel J. ; et
al. |
July 21, 2005 |
Adaptable electrochemical processing chamber
Abstract
An electrochemical processing chamber which can be modified for
treating different workpieces and methods for so modifying
electrochemical processing chambers. In one particular embodiment,
an electrochemical processing chamber 200 includes a plurality of
walls 510 defining a plurality of electrode compartments 520, each
electrode compartment having at least one electrode 600 therein,
and a virtual electrode unit 530 defining a plurality of flow
conduits, with at least one of the flow conduits being in fluid
communication with each of the electrode compartments. This first
virtual electrode unit 530 may be exchanged for a second virtual
electrode unit 540, without modification of any of the electrodes
600, to adapt the processing chamber 200 for treating a different
workpiece.
Inventors: |
Woodruff, Daniel J.;
(Kalispell, MT) ; Hanson, Kyle M.; (Kalispell,
MT) ; Eudy, Steve L.; (Bigfork, MT) ; Weber,
Curtis A.; (Columbia Falls, MT) ; Harris, Randy;
(Kalispell, MT) |
Correspondence
Address: |
PERKINS COIE LLP
P.O. BOX 1247
PATENT-SEA
SEATTLE
WA
98111-1247
US
|
Family ID: |
43706155 |
Appl. No.: |
11/081030 |
Filed: |
March 10, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11081030 |
Mar 10, 2005 |
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09875365 |
Jun 5, 2001 |
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09875365 |
Jun 5, 2001 |
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09804697 |
Mar 12, 2001 |
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6660137 |
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09804697 |
Mar 12, 2001 |
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PCT/US00/10120 |
Apr 13, 2000 |
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60129055 |
Apr 13, 1999 |
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Current U.S.
Class: |
205/128 |
Current CPC
Class: |
H01L 21/6719 20130101;
C25D 3/00 20130101; C25D 17/10 20130101; H01L 21/67751 20130101;
H01L 21/6723 20130101; C25D 7/123 20130101; C25D 17/001 20130101;
C25D 17/00 20130101 |
Class at
Publication: |
205/128 |
International
Class: |
B23H 007/26 |
Claims
1-20. (canceled)
21. An electrochemical processing chamber, comprising: a reaction
vessel having an interior; an electrode received in the interior of
the reaction vessel; and a first virtual electrode unit comprising
a dielectric material and defining a first virtual electrode in
fluid communication with the electrode, the first virtual electrode
unit being exchangeable for a second virtual electrode unit,
without necessitating modification of the electrode, to adapt the
processing chamber for treating a differently-sized workpiece.
22. An electrochemical processing chamber, comprising: a reaction
vessel having an inner surface; a first wall spaced from the inner
surface of the reaction vessel, the first wall being formed of a
dielectric material and electrically separating a first electrode
compartment from a second electrode compartment; a first electrode
positioned in the first electrode compartment and a second
electrode positioned in the second electrode compartment; and a
first virtual electrode unit comprising a dielectric material and
defining a first virtual electrode in fluid communication with the
first electrode compartment, the first partition also defining, in
part, a second virtual electrode in fluid communication with the
outer electrode compartment, the first virtual electrode unit being
exchangeable for a second virtual electrode unit, without
necessitating modification of the electrodes, to adapt the
processing chamber for treating a differently-sized workpiece.
23. The electrochemical processing chamber of claim 22 wherein the
first virtual electrode unit comprises a first partition having a
first section extending radially inwardly from the first wall and a
lip defining a circular opening.
24. The electrochemical processing chamber of claim 22 wherein the
first wall is carried by the first virtual electrode unit and is
removable therewith as a unit when exchanging the first virtual
electrode unit for the second virtual electrode unit.
25. The electrochemical processing chamber of claim 22 further
comprising a flow distributor having a first fluid outlet
associated with the first electrode compartment and a second fluid
outlet associated with the second electrode compartment.
26. The electrochemical processing chamber of claim 25 wherein the
first wall is carried by the first virtual electrode unit and the
first wall has a lower edge releasably received in an annular
recess in the flow distributor positioned between the first fluid
outlet and the second fluid outlet.
27. The electrochemical processing chamber of claim 22 wherein the
first virtual electrode comprises a central discharge opening
through which fluid may flow.
28. The electrochemical processing chamber of claim 27 wherein the
first virtual electrode receives an electrical potential via flow
of an electrically conductive fluid over the first electrode and
upwardly through the first virtual electrode.
29. The electrochemical processing chamber of claim 27 wherein the
second virtual electrode comprises an annular opening through which
fluid may flow.
30. The electrochemical processing chamber of claim 29 wherein the
second virtual electrode receives an electrical potential via flow
of an electrically conductive fluid over the second electrode and
upwardly through the second virtual electrode.
31. The electrochemical processing chamber of claim 22 wherein the
first virtual electrode receives a first electrical potential from
the first electrode.
32. The electrochemical processing chamber of claim 31 wherein the
second virtual electrode receives a second electrical potential
from the second electrode.
33. The electrochemical processing chamber of claim 22 wherein the
electrodes are anodes.
34. An electrochemical processing chamber, comprising: a plurality
of concentric walls defining a plurality of concentric annular
electrode compartments, the walls being formed of a dielectric
material; a plurality of electrodes, each of the electrode
compartments having at least one of the electrodes positioned
therein; a fluid distributor having a plurality of fluid channels,
each of the electrode compartments being in fluid communication
with at least one of the fluid channels; and a first virtual
electrode unit formed of a dielectric material, the first virtual
electrode unit defining a plurality of flow conduits, with at least
one of the flow conduits being in fluid communication with each of
the electrode compartments, the first virtual electrode unit being
exchangeable for a second virtual electrode unit, without
modification of any of the electrodes, to adapt the processing
chamber for treating a differently-sized workpiece.
35. The electrochemical processing chamber of claim 34 wherein the
walls are coupled to the first virtual electrode unit and can be
removed therewith as a unit.
36. The electrochemical processing chamber of claim 34 wherein the
walls are carried by the fluid distributor and remain attached
thereto when the virtual electrode unit is removed.
37. The electrochemical processing chamber of claim 34 wherein the
virtual electrode unit comprises a plurality of partitions, with
one partition being associated with each of the walls.
38. The electrochemical processing chamber of claim 37 wherein the
plurality of partitions are joined to one another such that the
virtual electrode unit may be exchanged as a unit.
39. The electrochemical processing chamber of claim 34 further
comprising a second virtual electrode unit exchangeable for the
first virtual electrode unit, each of the first and second virtual
electrode units being adapted to adjoin the walls at the same
radial distances from a center line of the processing chamber.
40. The electrochemical processing chamber of claim 34 an inner one
of the flow conduits of the first virtual electrode unit defines a
central discharge opening and each of the other flow conduits of
the first virtual electrode unit defines concentric annular
discharge openings.
41. The electrochemical processing chamber of claim 40 wherein each
of the flow conduits defines a separately controllable virtual
electrode.
42. The electrochemical processing chamber of claim 34 wherein each
of the flow conduits defines a separately controllable virtual
electrode.
43. The electrochemical processing chamber of claim 34 wherein the
first virtual electrode unit comprises a plurality of partitions,
each partition being having a first section and a lip, the first
section being coupled to one of the walls and extending radially
inwardly therefrom, the lip defining a circular opening.
44. The electrochemical processing chamber of claim 34 further
comprising a flow distributor having a plurality of fluid conduits,
with one fluid conduit being in fluid communication with each of
the electrode compartments.
45. The electrochemical processing chamber of claim 44 wherein the
walls are carried by the first virtual electrode unit and each of
the walls has a lower edge releasably received in a separate
annular recess in the flow distributor.
46. An electrochemical processing chamber, comprising: a reaction
vessel comprising: a vessel wall defining an interior of the
reaction vessel; and first and second electrodes, the first
electrode being spaced radially inwardly of the second electrode;
and a replaceable field shaping unit comprising: a first wall
removably received in the interior of the reaction vessel, the
first wall being formed of a dielectric material and electrically
separating a first electrode compartment from a second electrode
compartment, the first electrode being positioned within the first
electrode compartment and the second electrode being positioned
within the second electrode compartment; a virtual electrode unit
comprising a first partition formed of a dielectric material and
coupled to the first wall, the first partition defining a first
virtual electrode in fluid communication with the first electrode
compartment and defining, in part, a second virtual electrode in
fluid communication with the second electrode compartment; the
replaceable field shaping unit being removable from the reaction
vessel as a unit without necessitating modification of the reaction
vessel.
47. The electrochemical processing chamber of claim 46 wherein the
reaction vessel has an outer wall with an upper edge, an outer
portion of the virtual electrode unit engaging the upper edge of
the outer wall in defining the second electrode compartment.
48. An electrochemical processing chamber, comprising: a
replaceable first field shaping unit comprising: a plurality of
concentric walls electrically separating a plurality of concentric
electrode compartments; and a virtual electrode unit comprising a
plurality of partitions, each of the walls having a separate
partition coupled thereto, the virtual electrode unit defining a
plurality of virtual electrodes, with a separate virtual electrode
in fluid communication with each of the electrode compartments; and
a reaction vessel comprising: a vessel wall defining an interior
receiving the walls of the first replaceable field shaping unit;
and a plurality of electrodes, at least one of the electrodes being
positioned in each of the electrode compartments; the replaceable
first field shaping unit being removable from the reaction vessel
as a unit for replacement with a second field shaping unit, without
necessitating modification of any of the plurality of electrodes,
to adapt the electrochemical processing chamber for use with a
differently-sized workpiece.
49. The electrochemical processing chamber of claim 48 wherein the
second field shaping unit comprises: a plurality of concentric
walls adapted to electrically separate a plurality of concentric
electrode compartments when the plurality of walls is installed in
the interior of the reaction vessel; and a virtual electrode unit
comprising a plurality of partitions, each of the walls having a
separate partition coupled thereto, the virtual electrode unit
defining a plurality of virtual electrodes, with a separate virtual
electrode in fluid communication with each of the electrode
compartments when the second field shaping unit replaces the first
field shaping unit; a relative arrangement of the virtual
electrodes of the second replaceable field shaping unit being
different from a relative arrangement of the virtual electrodes of
the first field shaping unit, thereby facilitating adaptation of
the electrochemical processing chamber for use with the
differently-sized workpiece.
50. The electrochemical processing chamber of claim 48 further
comprising a flow distributor having a plurality of fluid conduits,
with one fluid conduit being in fluid communication with each of
the electrode compartments.
51. The electrochemical processing chamber of claim 50 wherein each
of the walls has a lower edge releasably received in a separate
annular recess in the flow distributor.
52. An electrochemical processing system, comprising: a reaction
vessel having an outer wall and a plurality of concentric, annular
electrodes, adjacent electrodes being spaced from one another to
define annular wall-receiving spaces therebetween; a replaceable
first field shaping unit comprising: a plurality of concentric
walls formed of a dielectric material and having upper edges, the
walls being positioned with respect to one another to be received
in the wall-receiving spaces between the electrodes to define a
plurality of concentric electrode compartments with at least one of
the electrodes being received within each of the electrode
compartments; and a first virtual electrode unit formed of a
dielectric material and coupled to the walls adjacent their upper
edges, the first virtual electrode unit being adapted to abut the
outer wall of the reaction vessel, the first virtual electrode unit
defining a first set of discharge openings having predefined
relative positions, each of the discharge openings of the first set
being adapted for fluid communication with one of the electrode
compartments, each discharge opening of the first set defining a
position of a virtual electrode; and a replaceable second field
shaping unit comprising: a plurality of concentric walls formed of
a dielectric material and having upper edges, the walls being
positioned with respect to one another to be received in the
wall-receiving spaces between the electrodes to define a plurality
of concentric electrode compartments with at least one of the
electrodes being received within each of the electrode
compartments; and a second virtual electrode unit formed of a
dielectric material and coupled to the walls adjacent their upper
edges, the second virtual electrode unit being adapted to abut the
outer wall of the reaction vessel, the second virtual electrode
unit defining a second set of discharge openings having predefined
relative positions, the relative positions of the discharge
openings of the second set differing from the relative positions of
the discharge openings of the first set, each of the discharge
openings of the second set being adapted for fluid communication
with one of the electrode compartments, each discharge opening of
the second set defining a position of an virtual electrode; the
first field shaping unit and the second field shaping unit each
being adapted for installation in and removal from the reaction
vessel as a unit.
53. The electrochemical processing chamber of claim 52 wherein the
reaction vessel further comprises a flow distributor adapted to
deliver processing fluid to each of the electrode compartments
defined when the first field shaping unit or the second field
shaping unit is installed in the reaction vessel.
54. The electrochemical processing chamber of claim 53 wherein the
flow distributor includes a plurality of spaced-apart annular
recesses, each of the walls of each of the field shaping units
having a lower edge sized to be releasably received in one of the
annular recesses when the field shaping unit is installed in the
reaction vessel.
55. The electrochemical processing chamber of claim 53 further
comprising a first contact assembly adapted to support a first
workpiece above the electrodes in a predefined position with
respect to the virtual electrodes of the first field shaping
unit.
56. The electrochemical processing chamber of claim 55 further
comprising a second contact assembly adapted to support a second
workpiece above the electrodes in a predefined position with
respect to the virtual electrodes of the second field shaping
unit.
57. An electrochemical processing chamber, comprising: a reaction
vessel having an interior; an electrode received in the interior of
the reaction vessel; a first virtual electrode unit comprising a
dielectric material and defining a first virtual electrode in fluid
communication with the electrode; and a first contact assembly
adapted to support workpiece in a predetermined position with
respect to the first virtual electrode; the first contact assembly
being exchangeable for a second contact assembly and the first
virtual electrode unit being exchangeable for a second virtual
electrode unit, without necessitating modification of the
electrode, to adapt the processing chamber for treating a
differently-sized workpiece.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 09/804,697, entitled "SYSTEM FOR
ELECTROCHEMICALLY PROCESSING A WORKPIECE," filed on Mar. 12, 2001;
which is a continuation of International Application No.
PCT/US00/10120, filed on Apr. 13, 2000, in the English language and
published in the English language as International Publication No.
WO00/61498, which claims the benefit of Provisional Application No.
60/129,055, filed on Apr. 13, 1999, all of which are herein
incorporated by reference. Additionally, this application is
related to the following:
[0002] (a) U.S. patent application entitled "TRANSFER DEVICES FOR
HANDLING MICROELECTRONIC WORKPIECES WITHIN AN ENVIRONMENT OF A
PROCESSING MACHINE AND METHODS OF MANUFACTURING AND USING SUCH
DEVICES IN THE PROCESSING OF MICROELECTRONIC WORKPIECES," filed
concurrently, and identified by Perkins Coie LLP Docket No.
29195.8153US00;
[0003] (b) U.S. patent application entitled "INTEGRATED TOOLS WITH
TRANSFER DEVICES FOR HANDLING MICROELECTRONIC WORKPIECES," filed
concurrently, and identified by Perkins Coie Docket No.
29195.8153US01;
[0004] (c) U.S. patent application entitled "DISTRIBUTED POWER
SUPPLIES FOR MICROELECTRONIC WORKPIECE PROCESSING TOOLS," filed
concurrently, and identified by Perkins Coie Docket No.
29195.8155US00;
[0005] (d) U.S. patent application entitled "APPARATUS AND METHODS
FOR ELECTROCHEMICAL PROCESSING OF MICROELECTRONIC WORKPIECES,"
filed concurrently, and identified by Perkins Coie LLP Docket No.
29195.8158US00;
[0006] (e) U.S. patent application entitled "LIFT AND ROTATE
ASSEMBLY FOR USE IN A WORKPIECE PROCESSING STATION AND A METHOD OF
ATTACHING THE SAME," filed concurrently, and identified by Perkins
Coie Docket No. 29195.8154US00;
[0007] (f) U.S. Patent Applications entitled "TUNING ELECTRODES
USED IN A REACTOR FOR ELECTROCHEMICALLY PROCESSING A
MICROELECTRONIC WORKPIECE," filed on May 4, 2001, and identified by
U.S. application Ser. No. 09/849,505, and two additional
applications filed on May 24, 2001, and identified separately by
Perkins Coie Docket Nos. 29195.8157US02 and 29195.8157US03.
[0008] All of the foregoing U.S. Patent Applications in paragraphs
(a)-(f) above are herein incorporated by reference.
TECHNICAL FIELD
[0009] This application relates to reaction vessels and methods of
making and using such vessels in electrochemical processing of
microelectronic workpieces.
BACKGROUND
[0010] Microelectronic devices, such as semiconductor devices and
field emission displays, are generally fabricated on and/or in
microelectronic workpieces using several different types of
machines ("tools"). Many such processing machines have a single
processing station that performs one or more procedures on the
workpieces. Other processing machines have a plurality of
processing stations that perform a series of different procedures
on individual workpieces or batches of workpieces. In a typical
fabrication process, one or more layers of conductive materials are
formed on the workpieces during deposition stages. The workpieces
are then typically subjected to etching and/or polishing procedures
(i.e., planarization) to remove a portion of the deposited
conductive layers for forming electrically isolated contacts and/or
conductive lines.
[0011] Plating tools that plate metals or other materials on the
workpieces are becoming an increasingly useful type of processing
machine. Electroplating and electroless plating techniques can be
used to deposit copper, solder, permalloy, gold, silver, platinum
and other metals onto workpieces for forming blanket layers or
patterned layers. A typical copper plating process involves
depositing a copper seed layer onto the surface of the workpiece
using chemical vapor deposition (CVD), physical vapor deposition
(PVD), electroless plating processes, or other suitable methods.
After forming the seed layer, a blanket layer or patterned layer of
copper is plated onto the workpiece by applying an appropriate
electrical potential between the seed layer and an anode in the
presence of an electroprocessing solution. The workpiece is then
cleaned, etched and/or annealed in subsequent procedures before
transferring the workpiece to another processing machine.
[0012] FIG. 1 illustrates an embodiment of a single-wafer
processing station 1 that includes a container 2 for receiving a
flow of electroplating solution from a fluid inlet 3 at a lower
portion of the container 2. The processing station 1 can include an
anode 4, a plate type diffuser 6 having a plurality of apertures 7,
and a workpiece holder 9 for carrying a workpiece 5. The workpiece
holder 9 can include a plurality of electrical contacts for
providing electrical current to a seed layer on the surface of the
workpiece 5. When the seed layer is biased with a negative
potential relative to the anode 4, it acts as a cathode. In
operation the electroplating fluid flows around the anode 4,
through the apertures 7 in the diffuser 6 and against the plating
surface of the workpiece 5. The electroplating solution is an
electrolyte that conducts electrical current between the anode 4
and the cathodic seed layer on the surface of the workpiece 5.
Therefore, ions in the electroplating solution plate the surface of
the workpiece 5.
[0013] The plating machines used in fabricating microelectronic
devices must meet many specific performance criteria. For example,
many processes must be able to form small contacts in vias that are
less than 0.5 .mu.m wide, and are desirably less than 0.1 .mu.m
wide. The plated metal layers accordingly often need to fill vias
or trenches that are on the order of 0.1 .mu.m wide, and the layer
of plated material should also be deposited to a desired, uniform
thickness across the surface of the workpiece 5. One factor that
influences the uniformity of the plated layer is the mass transfer
of electroplating solution at the surface of the workpiece. This
parameter is generally influenced by the velocity of the flow of
the electroplating solution perpendicular to the surface of the
workpiece. Another factor that influences the uniformity of the
plated layer is the current density of the electrical field across
the surface of the wafer.
[0014] One concern of existing electroplating equipment is
providing a uniform mass transfer at the surface of the workpiece.
Referring to FIG. 1, existing plating tools generally use the
diffuser 6 to enhance the uniformity of the fluid flow
perpendicular to the face of the workpiece. Although the diffuser 6
improves the uniformity of the fluid flow, it produces a plurality
of localized areas of increased flow velocity perpendicular to the
surface of the workpiece 5 (indicated by arrows 8). The localized
areas generally correspond to the position of the apertures 7 in
the diffuser 6. The increased velocity of the fluid flow normal to
the substrate in the localized areas increases the mass transfer of
the electroplating solution in these areas. This typically results
in faster plating rates in the localized areas over the apertures
7. Although many different configurations of apertures have been
used in plate-type diffusers, these diffusers may not provide
adequate uniformity for the precision required in many current
applications.
[0015] Existing plating tools are typically optimized for use with
a single size of workpiece. Hence, the anode 4 and the diffuser 6
will have a size and shape which is specific to a particular size
of workpiece. Using an anode 4 and diffuser 6 designed for one size
of workpiece to process a differently sized workpieces 5 will yield
inconsistent results. For example, a semiconductor wafer having a
150 mm diameter is small enough to fit in a processing station 1
designed for a 200 mm diameter wafer. Even if the workpiece holder
9 were modified to hold a 150 mm wafer, however, the flow patterns
and electric field characteristics of the anode 4 and diffuser 6
designed for a 200 mm wafer would yield an uneven plating layer on
the smaller 150 mm wafer.
[0016] As a result, adapting a processing station 1 to handle a
differently sized workpiece 5 typically will require substantial
modification. This will usually include replacing at least the
anode 4 and diffuser 6. Replacing these parts is frequently more
difficult and time consuming than the simple schematic diagram of
FIG. 1 would imply. This requires stocking separate supplies of
differently-sized anodes. If the anodes 4 are consumable, replacing
them is complicated by the fact that they require maintenance of a
passivated film layer for consistent operation. As a consequence,
manufacturers typically optimize the processing station to process
a single size workpiece and leave it unchanged. If the manufacturer
wishes to produce two different sizes of workpieces, the
manufacturer will commonly purchase an entirely separate processing
machine so that each machine need only handle one size.
SUMMARY OF THE INVENTION
[0017] Various embodiments of the present invention provide
electrochemical processing chambers and methods enabling a single
electrochemical processing chamber to be used to treat different
workpieces. Many of these embodiments permit a user to process
different workpieces (e.g., a 200 mm semiconductor wafer and a 300
mm semiconductor wafer) in the same electrochemical processing
chamber. For example, a processing chamber of the invention can
include a virtual electrode unit defining virtual electrodes.
Simply by replacing one virtual electrode unit for another in such
an embodiment, the effective electrical field in the processing
chamber can be modified. A further embodiment of the invention
incorporates a virtual electrode unit in a field shaping unit which
also includes one or more walls defining a separate compartment for
each electrode. If so desired, such a field shaping unit may be
replaced as a unit, further simplifying modification of the
processing chamber. Certain embodiments of the invention provide
methods which capitalize on the ease of replacing the virtual
electrode units to thereby alter the electrical field in an
electrochemical processing chamber to meet the processing needs for
different workpieces.
[0018] One embodiment of the invention provides a method of
modifying an electrochemical processing chamber from a first
configuration for treating a first workpiece to a second
configuration for treating a different second workpiece. The
processing chamber initially includes a reaction vessel having a
plurality of electrodes positioned in electrically separate
electrode compartments and a first virtual electrode unit. The
first virtual electrode unit defines a first set of virtual
electrodes adapted for treating the first workpiece, each of the
virtual electrodes being in fluid communication with one of the
electrode compartments. The method includes providing a second
virtual electrode unit which defines a second set of virtual
electrodes adapted for treating the second workpiece. The relative
positions of the virtual electrodes in the first set differ from
the relative positions of the virtual electrodes in the second set.
The first virtual electrode unit is replaced with the second
virtual electrode unit, thereby modifying an effective electric
field of the electrochemical processing chamber for treatment of
the second workpiece without necessitating modification of the
electrodes. This can extend the functionality of a processing line,
enabling a manufacturer to readily process different types of
workpieces in the same processing chamber rather than purchase a
separate processing line dedicated to each type of workpiece.
[0019] In more particular aspects of this embodiment, the electrode
compartments may be defined by a plurality of walls coupled to the
first virtual electrode unit, with the walls and the first virtual
electrode unit defining a first field shaping unit. With such a
field shaping unit, replacing the first virtual electrode unit may
comprise removing the first field shaping unit as a unit. The
second virtual electrode unit may also include a plurality of walls
coupled thereto to define a second field shaping unit, enabling the
second field shaping unit to be installed as a unit. In a further
embodiment, the first configuration of the processing chamber
includes a first contact assembly adapted to support the first
workpiece in a predetermined position with respect to the first set
of virtual electrodes. This enables treatment of the first
workpiece by defining an electrical potential between the
electrodes and the first workpiece. The first contact assembly may
also be replaced with a second contact assembly adapted to support
the second workpiece and the second workpiece may be treated by
defining an electrical potential between the electrodes and the
second workpiece.
[0020] Another embodiment of the invention provides a method of
effectuating electrochemical treatment of different first and
second workpieces. This method includes providing an initial
electrochemical processing chamber and a second virtual electrode
unit. The initial processing chamber includes a reaction vessel
having a plurality of electrodes in electrically separate electrode
compartments and a first virtual electrode unit defining a first
set of virtual electrodes. The second virtual electrode unit is
adapted to define a second set of virtual electrodes, with relative
positions of the virtual electrodes of the second virtual electrode
unit being different from relative positions of the virtual
electrodes of the first virtual electrode unit. A user is
instructed to treat the first workpiece with the initial processing
chamber; to replace the first virtual electrode unit with the
second virtual electrode unit, thereby modifying the initial
electrochemical processing chamber by repositioning the virtual
electrodes; and to treat the second workpiece with the modified
electrochemical processing chamber.
[0021] An alternative embodiment of the invention provides a method
of effectuating assembly of an electrochemical processing chamber.
In this method, a reaction vessel is provided, the reaction vessel
having an outer wall and a plurality of electrodes, adjacent
electrodes being spaced from one another to define a wall-receiving
space therebetween. A replaceable first field shaping unit is
provided, the first field shaping unit having a wall adapted to be
received in the wall-receiving space between the electrodes and a
first virtual electrode unit coupled to the wall. The first virtual
electrode unit defines a first set of virtual electrodes having
predefined relative positions. A second field shaping unit is
provided, the second field shaping unit having a wall adapted to be
received in the wall-receiving space between the electrodes and a
second virtual electrode unit coupled to the wall. The second
virtual electrode unit defines a second set of virtual electrodes
having predefined relative positions. At least one functional
characteristic of the first field shaping unit is identified and at
least one functional characteristic of the second field shaping
unit is identified. The identified functional characteristic of the
first field shaping unit is different from the identified
functional characteristic of the second field shaping unit,
enabling a user to select between the first and second field
shaping units to adapt the reaction vessel to treat a selected type
of workpiece.
[0022] As noted above, other aspects of the invention provide
electrochemical processing chambers. One such embodiment includes a
reaction vessel, an electrode in an interior of the reaction
vessel, and a first virtual electrode unit. The first virtual
electrode unit defines a first virtual electrode in fluid
communication with the electrode. The first virtual electrode unit
is exchangeable for a second virtual electrode unit, without
necessitating modification of the electrode, to adapt the
processing chamber for treating a different workpiece. Such an
adaptable processing chamber permits a manufacturer significant
flexibility in producing a variety of products with minimal
downtime.
[0023] An electrochemical processing chamber of another embodiment
includes a reaction vessel having an inner surface and a first wall
spaced from the inner surface of the reaction vessel. The first
wall, which may be formed of a dielectric material, electrically
separates a first electrode compartment, which receives a first
electrode, from a second electrode compartment, which receives a
second electrode. A first virtual electrode unit, which may
comprise a dielectric material, defines a first virtual electrode
in fluid communication with the first electrode compartment. The
first virtual electrode unit also defines, in part, a second
virtual electrode in fluid communication with the outer electrode
compartment. The first virtual electrode unit is exchangeable for a
second virtual electrode unit, without necessitating modification
of the electrodes, to adapt the processing chamber for treating a
different workpiece. Avoiding the need to modify the electrodes in
this fashion allows a manufacturer to adapt this embodiment to be
used with different workpieces quickly and without need for a
separate inventory of different electrodes for each type of
workpiece to be produced.
[0024] Yet another embodiment of the invention provides an
electrochemical processing chamber including a reaction vessel and
a replaceable field shaping unit. The reaction vessel includes a
vessel wall and first and second electrodes, the first electrode
being spaced radially inwardly of the second electrode. The field
shaping unit includes a first wall, which electrically separates a
first electrode compartment within which the first electrode is
positioned, from a second electrode compartment within which the
second electrode is positioned. The field shaping unit also
includes a virtual electrode unit including a dielectric first
partition coupled to the first wall. The first partition defines a
first virtual electrode in fluid communication with the first
electrode compartment and defines, in part, a second virtual
electrode in fluid communication with the second electrode
compartment. The replaceable field shaping unit is removable from
the reaction vessel as a unit without necessitating modification of
the reaction vessel. If so desired, the first field shaping unit of
this embodiment may include a plurality of concentric walls
electrically separating a plurality of concentric electrode
compartments. The field shaping unit may also comprise a plurality
of partitions and define a plurality of virtual electrodes, with a
separate virtual electrode in fluid communication with each of the
electrode compartments. The unit-based approach to modification
afforded by this embodiment can ease transition from one type of
workpiece to another.
[0025] An electrochemical processing system in accordance with one
additional embodiment of the invention includes a reaction vessel,
a replaceable first field shaping unit and a replaceable second
field shaping unit. The reaction vessel includes an outer wall and
a plurality of annular electrodes spaced from one another to define
annular wall-receiving spaces therebetween. The first field shaping
unit includes a plurality of concentric walls and a first virtual
electrode unit. The walls may be positioned with respect to one
another to be received in the wall-receiving spaces between the
electrodes to define a plurality of concentric electrode
compartments. The first virtual electrode unit may be coupled to
the walls adjacent their upper edges and adapted to abut the outer
wall of the reaction vessel adjacent the upper edge thereof. The
first virtual electrode unit defines a first set of discharge
openings having predefined relative positions, each of the
discharge openings of the first set being adapted for fluid
communication with one of the electrode compartments, with each
discharge opening of the first set defining a position of an
virtual electrode. The replaceable second field shaping unit is
much like the first field shaping unit, but has a second set of
discharge openings with relative positions differing from the
relative positions of the discharge openings of the first set. The
first field shaping unit and the second field shaping unit are each
adapted for installation in and removal from the reaction vessel as
a unit. Providing such a reaction vessel and different field
shaping units allows a manufacturer to configure the
electrochemical processing system to meet current production needs
with a minimum of difficulty and wasted workpiece-dependent
components.
[0026] Still another embodiment of the invention provides an
electrochemical processing chamber including a reaction vessel
having an interior; an electrode received in the interior of the
reaction vessel; a first virtual electrode unit and a first contact
assembly. The first virtual electrode unit, which may comprise a
dielectric material, defines a first virtual electrode in fluid
communication with the electrode. The first contact assembly is
adapted to support a workpiece in a predetermined position with
respect to the first virtual electrode. The first contact assembly
is exchangeable for a second contact assembly and the first virtual
electrode unit is exchangeable for a second virtual electrode unit,
without necessitating modification of the electrode, to adapt the
processing chamber for treating a differently-sized workpiece.
Providing exchangeable contact assemblies and exchangeable virtual
electrode units in accordance with this embodiment extends
functionality of the processing chamber without requiring complex,
time-consuming changes to switch from one size of workpiece to
another.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a schematic diagram of an electroplating chamber
in accordance with the prior art.
[0028] FIG. 2 is an isometric view of an electroprocessing machine
having electroprocessing stations for processing microelectronic
workpieces in accordance with an embodiment of the invention.
[0029] FIG. 3 is a cross-sectional view of an electroprocessing
station having a processing chamber for use in an electroprocessing
machine in accordance with an embodiment of the invention. Selected
components in FIG. 3 are shown schematically.
[0030] FIG. 4 is a schematic cross-sectional view of an
electrochemical processing chamber in accordance with one
embodiment of the invention.
[0031] FIG. 5 is a schematic cross-sectional view of the
electrochemical processing chamber of FIG. 4 modified to process a
differently-sized workpiece.
[0032] FIG. 6 is an isometric view showing a cross-sectional
portion of a processing chamber taken along line 6-6 of FIG.
10A.
[0033] FIGS. 7A-7D are cross-sectional views of a distributor for a
processing chamber in accordance with an embodiment of the
invention.
[0034] FIG. 8 is an isometric view showing a different
cross-sectional portion of the processing chamber of FIG. 6 taken
along line 8-8 of FIG. 10B.
[0035] FIG. 9A is an isometric view of an interface assembly for
use in a processing chamber in accordance with an embodiment of the
invention.
[0036] FIG. 9B is a cross-sectional view of the interface assembly
of FIG. 9A.
[0037] FIGS. 10A and 10B are top plan views of a processing chamber
that provide a reference for the isometric, cross-sectional views
of FIGS. 6 and 8, respectively.
[0038] FIG. 11 is an isometric view schematically showing removal
of a field shaping unit from the processing chamber of FIG. 6.
[0039] FIG. 12 is an isometric view similar to FIG. 6, showing a
cross-sectional portion of a processing chamber modified in
accordance with another embodiment of the invention.
[0040] FIG. 13 is a schematic cross-sectional view of the
electroprocessing station of FIG. 3 modified to process a
differently-sized workpiece.
DETAILED DESCRIPTION
[0041] The following description discloses the details and features
of several embodiments of electrochemical reaction vessels for use
in electrochemical processing stations and integrated tools to
process microelectronic workpieces. The term "microelectronic
workpiece" is used throughout to include a workpiece formed from a
substrate upon which and/or in which microelectronic circuits or
components, data storage elements or layers, and/or
micro-mechanical elements are fabricated. It will be appreciated
that several of the details set forth below are provided to
describe the following embodiments in a manner sufficient to enable
a person skilled in the art to make and use the disclosed
embodiments. Several of the details and advantages described below,
however, may not be necessary to practice certain embodiments of
the invention. Additionally, the invention can also include
additional embodiments that are within the scope of the claims, but
are not described in detail with respect to FIGS. 2-13.
[0042] The operation and features of electrochemical reaction
vessels are best understood in light of the environment and
equipment in which they can be used to electrochemically process
workpieces (e.g., electroplate and/or electropolish). As such,
embodiments of integrated tools with processing stations having the
electrochemical reaction vessels are initially described with
reference to FIGS. 2 and 3. The details and features of several
embodiments of electrochemical reaction vessels and methods for
adapting the vessels to process different types of workpieces are
then described with reference to FIGS. 4-13.
[0043] A. Selected Embodiments of Integrated Tools with
Electrochemical Processing Stations
[0044] FIG. 2 is an isometric view of a processing machine 100
having an electrochemical processing station 120 in accordance with
an embodiment of the invention. A portion of the processing machine
100 is shown in a cut-away view to illustrate selected internal
components. In one aspect of this embodiment, the processing
machine 100 can include a cabinet 102 having an interior region 104
defining an interior enclosure that is at least partially isolated
from an exterior region 105. The cabinet 102 can also include a
plurality of apertures 106 (only one shown in FIG. 1) through which
microelectronic workpieces 101 can ingress and egress between the
interior region 104 and a load/unload station 110.
[0045] The load/unload station 110 can have two container supports
112 that are each housed in a protective shroud 113. The container
supports 112 are configured to position workpiece containers 114
relative to the apertures 106 in the cabinet 102. The workpiece
containers 114 can each house a plurality of microelectronic
workpieces 101 in a "mini" clean environment for carrying a
plurality of workpieces through other environments that are not at
clean room standards. Each of the workpiece containers 114 is
accessible from the interior region 104 of the cabinet 102 through
the apertures 106.
[0046] The processing machine 100 can also include a plurality of
electrochemical processing stations 120 and a transfer device 130
in the interior region 104 of the cabinet 102. The processing
machine 100, for example, can be a plating tool that also includes
clean/etch capsules 122, electroless plating stations, annealing
stations, and/or metrology stations.
[0047] The transfer device 130 includes a linear track 132
extending in a lengthwise direction of the interior region 104
between the processing stations. The transfer device 130 can
further include a robot unit 134 carried by the track 132. In the
particular embodiment shown in FIG. 2, a first set of processing
stations is arranged along a first row R.sub.1-R.sub.1 and a second
set of processing stations is arranged along a second row
R.sub.2-R.sub.2. The linear track 132 extends between the first and
second rows of processing stations, and the robot unit 134 can
access any of the processing stations along the track 132.
[0048] FIG. 3 illustrates an embodiment of an
electrochemical-processing chamber 120 having a head assembly 150
and a processing chamber 200. The head assembly 150 includes a spin
motor 152, a rotor 154 coupled to the spin motor 152, and a contact
assembly 160 carried by the rotor 154. The rotor 154 can have a
backing plate 155 and a seal 156. The backing plate 155 can move
transverse to a workpiece 101 (arrow T) between a first position in
which the backing plate 155 contacts a backside of the workpiece
101 (shown in solid lines in FIG. 3) and a second position in which
it is spaced apart from the backside of the workpiece 101 (shown in
broken lines in FIG. 3). The contact assembly 160 can have a
support member 162, a plurality of contacts 164 carried by the
support member 162, and a plurality of shafts 166 extending between
the support member 162 and the rotor 154. The contacts 164 can be
ring-type spring contacts or other types of contacts that are
configured to engage a portion of the seed-layer on the workpiece
101. Commercially available head assemblies 150 and contact
assemblies 160 can be used in the electroprocessing chamber 120.
Particular suitable head assemblies 150 and contact assemblies 160
are disclosed in U.S. Pat. Nos. 6,228,232 and 6,080,691; and U.S.
application Ser. Nos. 09/385,784; 09/386,803; 09/386,610;
09/386,197; 09/501,002; 09/733,608; and 09/804,696, all of which
are herein incorporated by reference.
[0049] The processing chamber 200 includes an outer housing 202
(shown schematically in FIG. 3) and a reaction vessel 204 (also
shown schematically in FIG. 3) in the housing 202. The reaction
vessel 204 carries at least one electrode (not shown in FIG. 3) and
directs a flow of electroprocessing solution to the workpiece 101.
The electroprocessing solution, for example, can flow over a weir
(arrow F) and into the external housing 202, which captures the
electroprocessing solution and sends it back to a tank. Several
embodiments of reaction vessels 204 are shown and described in
detail with reference to FIGS. 4-12.
[0050] In operation the head assembly 150 holds the workpiece at a
workpiece-processing site of the reaction vessel 204 so that at
least a plating surface of the workpiece engages the
electroprocessing solution. An electrical field is established in
the solution by applying an electrical potential between the
plating surface of the workpiece via the contact assembly 160 and
one or more electrodes in the reaction vessel 204. For example, the
contact assembly 160 can be biased with a negative potential with
respect to the electrode(s) in the reaction vessel 204 to plate
materials onto the workpiece. On the other hand the contact
assembly 160 can be biased with a positive potential with respect
to the electrode(s) in the reaction vessel 204 to (a) de-plate or
electropolish plated material from the workpiece or (b) deposit
other materials (e.g., electrophoric resist). In general,
therefore, materials can be deposited on or removed from the
workpiece with the workpiece acting as a cathode or an anode
depending upon the particular type of material used in the
electrochemical process.
[0051] B. Selected Embodiments of Reaction Vessels for use in
Electrochemical Processing Chambers
[0052] FIGS. 4, 5 and 13 schematically illustrate aspects of
processing chambers 200 in accordance with certain embodiments of
the invention. Several embodiments of reaction vessels 204 for use
in processing chambers 200 are shown in more detail in FIGS.
6-12.
[0053] The processing chamber 200 of FIG. 4 includes a reaction
vessel 204 positioned beneath a contact assembly 160. The contact
assembly 160 carries a workpiece 101 which may be brought into
contact with the electroprocessing solution in the reaction vessel
204. For ease of explanation, FIG. 4 shows the contact assembly 160
and workpiece 101 spaced above the position they would occupy with
respect to the reaction vessel in processing the workpiece.
[0054] The reaction vessel 204 of FIG. 4 has a plurality of annular
electrodes 600a-d received therein. This particular embodiment
employs four separate electrodes 600a-d, but it should be
understood that any number of electrodes could be employed. While
it is anticipated that there will be at least one electrode, there
can be more than the four electrodes shown in FIG. 4. The
electrodes may be connected to a common power supply 610, or each
of the electrodes 600 may be provided with a separate power supply.
FIG. 4 shows a power supply 610 electrically coupled to the contact
assembly and to a power supply controller 625, which may
independently control the power delivered to each of the electrodes
600a-d. In this fashion, a desired potential may be created between
the workpiece 101 and each of the electrodes 600.
[0055] The electrodes 600 in FIG. 4 are housed in electrically
separate electrode compartments 520. These electrode compartments
520 may be defined by a plurality of walls 510 received in the
interior of the reaction vessel 204. In particular, a first
electrode compartment 520a is defined by a first wall 510a and a
second wall 510b, a second electrode compartment 520b is defined by
the second wall 510b and a third wall 510c, a third electrode
compartment 520c is defined by the third wall 510c and a fourth
wall 510d, and a fourth electrode compartment 520d is defined by
the fourth wall 510d and the outer wall 222 of the reaction vessel
204. The walls 510a-d of this embodiment are concentric annular
dividers that define annular electrode compartments 520a-d.
[0056] The processing chamber 200 also includes a virtual electrode
unit 530 which individually shapes the electrical fields produced
by the electrodes 600a-d. This virtual electrode unit 530 may
define one or more "virtual electrodes" that define the effective
shape, size and position of the electrical field perceived by the
workpiece. In one embodiment of the invention, the virtual
electrode unit 530 defines a separate virtual electrode associated
with each of the electrode compartments 520a-d. Hence, a first
virtual electrode VE.sub.1 is associated with the first electrode
compartment 520a, a second virtual electrode VE.sub.2 is associated
with the second electrode compartment 520b, a third virtual
electrode VE.sub.3 is associated with the third electrode
compartment 520c, and a fourth virtual electrode VE.sub.4 is
associated with the fourth electrode compartment 520d. Each of the
virtual electrodes VE may be electrically connected to the
electrode 600 received in the associated electrode compartment
520.
[0057] In one embodiment, the virtual electrodes VE are
electrically associated with the electrode 600 in the associated
electrode compartment 520 via flow of an electrically conductive
processing fluid through the electrode compartment. As a result,
each of the virtual electrodes VE receive an electrical potential
with respect to the workpiece 101 from the associated electrode
600. Processing fluid may be delivered to the various electrode
compartments via a distributor 300. For example, fluid from the
distributor 300 will flow upwardly through the fourth electrode
compartment 520d, passing over the fourth electrode 600d, then flow
upwardly through the fourth virtual electrode VE.sub.4 via a flow
conduit in the virtual electrode unit 530. In this embodiment,
therefore, the shape and size of each virtual electrode is defined
by the shape and size of an opening in the virtual electrode unit
530 in fluid communication with one of the electrode compartments.
Other embodiments of the invention may utilize virtual electrodes
which need not be defined by the passage of fluid through an
opening. As explained below in connection with FIG. 8, for example,
ion-permeable membranes may limit the passage of bulk fluid from
the electrode compartments 520b-d, instead merely passing ions
through the membrane and to the associated virtual electrode.
[0058] In one embodiment, one or more of the walls 510a-d are
coupled to the virtual electrode unit 530 to define a field shaping
unit 500. Coupling the walls 510 to the virtual electrode unit 530
allows the field shaping unit to be removed from the reaction
vessel as a unit. In one embodiment detailed below, the electrodes
600 remain in place in the reaction vessel 204 when the field
shaping unit 500 is removed. If so desired, however, the electrodes
600 may be carried by the field shaping unit 500, such as by
attaching electrodes 600 to the walls 510 or providing an
electrically conductive coating on the walls 510 which can be
electrically coupled to the power supply 620 or power supply
controller 625 when the walls 510 are received in the reaction
vessel 204 for processing a workpiece.
[0059] FIG. 5 illustrates the processing chamber 200 of FIG. 4,
also in a schematic fashion. In FIG. 5, however, the processing
chamber 200 has been modified to process a workpiece 101a which is
smaller than the workpiece 101 shown in FIG. 4. Many features of
the processing chamber 200 shown in FIG. 5 can be the same as those
described in connection with FIG. 4, and thus like reference
numbers refer to like parts in these Figures. The primary
differences between the embodiment of FIG. 4 and the embodiment of
FIG. 5 relate to the contact assembly and the virtual electrode
assembly. In particular, the contact assembly 161 of FIG. 5 is
adapted to hold a smaller workpiece than is the contact assembly
160 of FIG. 4 and the virtual electrode unit 540 in FIG. 5 defines
a different arrangement of virtual electrodes VE than does the
virtual electrode unit 530 of FIG. 4.
[0060] The virtual electrode unit 530 in FIG. 4 has virtual
electrodes VE.sub.1-4 which are sized and have relative positions
adapted to process the larger first workpiece 101. The virtual
electrodes VE.sub.1-4 of the virtual electrode unit 540 in FIG. 5
may have different sizes and/or relative positions from the virtual
electrodes VE.sub.1-4 in the virtual electrode unit 530 in FIG. 4.
In particular, the virtual electrodes VE of FIG. 4 may be optimized
for processing the first workpiece 101 whereas the virtual
electrodes VE of FIG. 5 may be optimized for processing the second
workpiece 101a. As a consequence, the effective electrical field in
the vicinity of the workpiece can be changed depending on the
particular needs of different workpieces.
[0061] The processing chamber 200 may be modified from the
configuration shown in FIG. 4 to the configuration shown in FIG. 5
by replacing the contact assembly 160 with a new contact assembly
161 and by replacing the virtual electrode unit 530 with a new
virtual electrode unit 540. In some circumstances, it may not be
necessary to replace the contact assembly, for example, when the
two workpieces 101 and 101a are the same size, but have different
processing requirements requiring different electrical fields.
Hence, the processing chamber 200 can be quickly and easily
modified from one configuration adapted to process a first
workpiece 101 to a different configuration adapted to process a
second workpiece 101a simply by replacing one virtual electrode
unit 530 with a different virtual electrode unit 540. If the walls
510 are coupled to the virtual electrode unit 530 for removal of
the field shaping unit 500 as a unit, the other virtual electrode
unit 540 may also have walls 510 coupled thereto to define a
different field shaping unit which can be placed in the reaction
vessel 204 in the same position previously occupied by the previous
field shaping unit 500. Similarly, if the electrodes 600 are
carried by the walls 510 of the initial field shaping unit 500
shown in FIG. 4 for removal therewith as a unit, the replacement
field shaping unit may also have electrodes 600 carried by its
walls 510.
[0062] Hence, in accordance with several embodiments of the
invention, a processing chamber 200 can be modified to process
different workpieces in a simple, straightforward manner. In one
embodiment explained below, this simplifies modifying an existing
processing chamber 200 from a first configuration for treating a
first workpiece to a second configuration for treating a different
second workpiece. In another embodiment explained below, this
enables a manufacturer greater flexibility in manufacturing
processing lines customized to treat different workpieces.
[0063] FIG. 6 more specifically illustrates an embodiment of a
housing 202 receiving a reaction vessel 204 similar, in some
respects, to the reaction vessel 204 shown schematically in FIG. 4.
As many features of the reaction vessel 204 shown in FIG. 6 can be
the same as those described with reference to FIGS. 4 and 5, like
reference numbers refer to like parts in these Figures. The housing
202 in FIG. 6 can have a drain 210 for returning the processing
fluid that flows out of the reaction vessel 204 to a storage tank,
and a plurality of openings for receiving inlets and electrical
fittings. The reaction vessel 204 can include an outer container
220 having an outer wall 222 spaced radially inwardly of the
housing 202. The outer container 220 can also have a spiral spacer
224 between the outer wall 222 and the housing 202 to provide a
spiral ramp (i.e., a helix) on which the processing fluid can flow
downward to the bottom of the housing 202. The spiral ramp reduces
the turbulence of the return fluid to inhibit entrainment of gasses
in the return fluid.
[0064] FIGS. 4 and 5 illustrate reaction vessels 204 with
distributors 300 receiving a flow of fluid from a single inlet. The
particular embodiment of the reaction vessel 204 shown in FIG. 6,
however, can include a distributor 300 for receiving a primary
fluid flow F.sub.p and a secondary fluid flow F.sub.2, a primary
flow guide 400 coupled to the distributor 300 to condition the
primary fluid flow F.sub.p, and a field shaping unit 500 coupled to
the distributor 300 to contain the secondary flow F.sub.2 in a
manner that shapes the electrical field in the reaction vessel 204.
The reaction vessel 204 can also include at least one electrode 600
in a compartment of the field shaping unit 500 and at least one
filter or other type of interface member 700 carried by the field
shaping unit 500 downstream from the electrode. The primary flow
guide 400 can condition the primary flow F.sub.p by projecting this
flow radially inwardly relative to a common axis A-A, and a portion
of the field shaping unit 500 directs the conditioned primary flow
F.sub.p toward the workpiece. In several embodiments, the primary
flow passing through the primary flow guide 400 and the center of
the field shaping unit 500 controls the mass transfer of processing
solution at the surface of the workpiece. The field shaping unit
500 also defines the shape the electric field, and it can influence
the mass transfer at the surface of the workpiece if the secondary
flow passes through the field shaping unit. The reaction vessel 204
can also have other configurations of components to guide the
primary flow F.sub.p and the secondary flow F.sub.2 through the
processing chamber 200. The reaction vessel 204, for example, may
not have a distributor in the processing chamber, but rather
separate fluid lines with individual flows can be coupled to the
vessel 204 to provide a desired distribution of fluid through the
primary flow guide 400 and the field shaping unit. For example, the
reaction vessel 204 can have a first outlet in the outer container
220 for introducing the primary flow into the reaction vessel and a
second outlet in the outer container for introducing the secondary
flow into the reaction vessel 204. Each of these components is
explained in more detail below.
[0065] FIGS. 7A-7D illustrate an embodiment of the distributor 300
for directing the primary fluid flow to the primary flow guide 400
and the secondary fluid flow to the field shaping unit 500.
Referring to FIG. 7A, the distributor 300 can include a body 310
having a plurality of annular steps 312 (identified individually by
reference numbers 312a-d) and annular grooves 314 in the steps 312.
The outermost step 312d is radially inward of the outer wall 222
(shown in broken lines) of the outer container 220 (FIG. 6), and
each of the interior steps 312a-c can carry an annular wall (shown
in broken lines) of the field shaping unit 500 in a corresponding
groove 314. The distributor 300 can also include a first inlet 320
for receiving the primary flow F.sub.p and a plenum 330 for
receiving the secondary flow F.sub.2. The first inlet 320 can have
an inclined, annular cavity 322 to form a passageway 324 (best
shown in FIG. 6) for directing the primary fluid flow F.sub.p under
the primary flow guide 400. The distributor 300 can also have a
plurality of upper orifices 332 along an upper part of the plenum
330 and a plurality of lower orifices 334 along a lower part of the
plenum 330. As explained in more detail below, the upper and lower
orifices are open to channels through the body 310 to distribute
the secondary flow F.sub.2 to the risers of the steps 312. The
distributor 300 can also have other configurations, such as a
"step-less" disk or non-circular shapes.
[0066] FIGS. 7A-7D further illustrate one configuration of channels
through the body 310 of the distributor 300. Referring to FIG. 7A,
a number of first channels 340 extend from some of the lower
orifices 334 to openings at the riser of the first step 312a. FIG.
7B shows a number of second channels 342 extending from the upper
orifices 332 to openings at the riser of the second step 312b, and
FIG. 7C shows a number of third channels 344 extending from the
upper orifices 332 to openings at the riser of the third step 312c.
Similarly, FIG. 7D illustrates a number of fourth channels 346
extending from the lower orifices 334 to the riser of the fourth
step 312d.
[0067] The particular embodiment of the channels 340-346 in FIGS.
7A-7D are configured to transport bubbles that collect in the
plenum 330 radially outward as far as practical so that these
bubbles can be captured and removed from the secondary flow
F.sub.2. This is beneficial because the field shaping unit 500
removes bubbles from the secondary flow F.sub.2 by sequentially
transporting the bubbles radially outwardly through electrode
compartments. For example, a bubble B in the compartment above the
first step 312a can sequentially cascade through the compartments
over the second and third steps 312b-c, and then be removed from
the compartment above the fourth step 312d. The first channel 340
(FIG. 7A) accordingly carries fluid from the lower orifices 334
where bubbles are less likely to collect to reduce the amount of
gas that needs to cascade from the inner compartment above the
first step 312a all the way out to the outer compartment. The
bubbles in the secondary flow F.sub.2 are more likely to collect at
the top of the plenum 330 before passing through the channels
340-346. The upper orifices 332 are accordingly coupled to the
second channel 342 and the third channel 344 to deliver these
bubbles outward beyond the first step 312a so that they do not need
to cascade through so many compartments. In this embodiment, the
upper orifices 332 are not connected to the fourth channels 346
because this would create a channel that inclines downwardly from
the common axis such that it may conflict with the groove 314 in
the third step 312c. Thus, the fourth channel 346 extends from the
lower orifices 334 to the fourth step 312d.
[0068] Referring again to FIG. 6, the primary flow guide 400
receives the primary fluid flow F.sub.p via the first inlet 320 of
the distributor 300. In one embodiment, the primary flow guide 400
includes an inner baffle 410 and an outer baffle 420. The inner
baffle can have a base 412 and a wall 414 projecting upward and
radially outward from the base 412. The wall 414, for example, can
have an inverted frusto-conical shape and a plurality of apertures
416. The apertures 416 can be holes, elongated slots or other types
of openings. In the illustrated embodiment, the apertures 416 are
annularly extending radial slots that slant upward relative to the
common axis to project the primary flow radially inward and upward
relative to the common axis along a plurality of diametrically
opposed vectors. The inner baffle 410 can also include a locking
member 418 that couples the inner baffle 410 to the distributor
300.
[0069] The outer baffle 420 can include an outer wall 422 with a
plurality of apertures 424. In this embodiment, the apertures 424
are elongated slots extending in a direction transverse to the
apertures 416 of the inner baffle 410. The primary flow F.sub.p
flows through (a) the first inlet 320, (b) the passageway 324 under
the base 412 of the inner baffle 410, (c) the apertures 424 of the
outer baffle 420, and then (d) the apertures 416 of the inner
baffle 410. The combination of the outer baffle 420 and the inner
baffle 410 conditions the direction of the flow at the exit of the
apertures 416 in the inner baffle 410. The primary flow guide 400
can thus project the primary flow along diametrically opposed
vectors that are inclined upward relative to the common axis to
create a fluid flow that has a highly uniform velocity. In
alternate embodiments, the apertures 416 do not slant upward
relative to the common axis such that they can project the primary
flow normal, or even downward, relative to the common axis.
[0070] FIG. 6 also illustrates an embodiment of the field shaping
unit 500 that receives the primary fluid flow F.sub.p downstream
from the primary flow guide 400. The field shaping unit 500 also
contains the second fluid flow F.sub.2 and shapes the electrical
field within the reaction vessel 204. In this embodiment, the field
shaping unit 500 has a compartment structure with a plurality of
walls 510 (identified individually by reference numbers 510a-d)
that define a plurality of electrode compartments 520 (identified
individually by reference numbers 520a-d). The walls 510 can be
annular skirts or dividers, and they can be received in one of the
annular grooves 314 in the distributor 300. In one embodiment, the
walls 510 are not fixed to the distributor 300 so that the field
shaping unit 500 can be quickly removed from the distributor 300.
For example, each of the walls 510 may have a lower edge which is
releasably received in the annular grooves 314 in the distributor
300. This allows easy access to the electrode compartments 520
and/or quick removal of the field shaping unit 500 as a unit to
change the shape of the electric field, as explained in more detail
below.
[0071] The field shaping unit 500 can have at least one wall 510
outward from the primary flow guide 400 to prevent the primary flow
F.sub.p from contacting an electrode. In the particular embodiment
shown in FIGS. 6 and 8, the field shaping unit 500 has a first
electrode compartment 520a between the first and second walls
510a-b, a second electrode compartment 520b between the second and
third walls 510b-c, a third electrode compartment 520c between the
third and fourth walls 510c-d, and a fourth electrode compartment
520d between the fourth wall 510d and the outer wall 222 of the
container 220. Although the walls 510a-d of FIG. 6 define annular
electrode compartments 520a-d, alternate embodiments of the field
shaping unit can have walls with different configurations to create
non-annular electrode compartments and/or each electrode
compartment can be further divided into cells. The second-fourth
walls 510b-d can also include holes 522 for allowing bubbles in the
first-third electrode compartments 520a-c to "cascade" radially
outward to the next outward electrode compartment 520 as explained
above with respect to FIGS. 7A-7D. The bubbles can then exit the
fourth electrode compartment 520d through an exit hole 525 through
the outer wall 222. In an alternate embodiment, the bubbles can
exit through an exit hole 524.
[0072] The electrode compartments 520 provide electrically discrete
compartments to house an electrode assembly having at least one
electrode and generally two or more electrodes 600 (identified
individually by reference numbers 600a-d). The electrodes 600 can
be annular members (e.g., annular rings or arcuate sections) that
are configured to fit within annular electrode compartments, or
they can have other shapes appropriate for the particular workpiece
(e.g., rectilinear). In the illustrated embodiment, for example,
the electrode assembly includes a first annular electrode 600a in
the first electrode compartment 520a, a second annular electrode
600b in the second electrode compartment 520b, a third annular
electrode 600c in the third electrode compartment 520c, and a
fourth annular electrode 600d in the fourth electrode compartment
520d. The electrodes 600 may be supported in the reaction vessel
204 in any suitable fashion. In the particular embodiment shown in
FIG. 6, the electrodes are supported by pillars 602 which extend
upwardly from a bottom of the reaction vessel 204. These pillars
602 may be hollow, serving as a guide for wires 604 connecting the
electrodes 600 to power supplies. As explained in U.S. Application
No. 60/206,661, Ser. Nos. 09/845,505, and 09/804,697, all of which
are incorporated herein by reference, each of the electrodes 600a-d
can be biased with the same or different potentials with respect to
the workpiece to control the current density across the surface of
the workpiece. In alternate embodiments, the electrodes 600 can be
non-circular shapes or sections of other shapes.
[0073] Embodiments of the reaction vessel 204 that include a
plurality of electrodes provide several benefits for plating or
electropolishing. In plating applications, for example, the
electrodes 600 can be biased with respect to the workpiece at
different potentials to provide uniform plating on different
workpieces even though the seed layers vary from one another or the
bath(s) of electroprocessing solution have different conductivities
and/or concentrations of constituents. Additionally, another the
benefit of having a multiple electrode design is that plating can
be controlled to achieve different final fill thicknesses of plated
layers or different plating rates during a plating cycle or in
different plating cycles. Other benefits of particular embodiments
are that the current density can be controlled to (a) provide a
uniform current density during feature filling and/or (b) achieve
plating to specific film profiles across a workpiece (e.g.,
concave, convex, flat). Accordingly, the multiple electrode
configurations in which the electrodes are separate from one
another provide several benefits for controlling the
electrochemical process to (a) compensate for deficiencies or
differences in seed layers between workpieces, (b) adjust for
variances in baths of electroprocessing solutions, and/or (c)
achieve predetermined feature filling or film profiles.
[0074] In the illustrated embodiment, the adjacent electrodes 600
are spaced from one another to define annular spaces for receiving
a wall 510. Hence, the second wall 510b is received in the annular
space between the first electrode 600a and the second electrode
600b, the third wall 510c is received in the annular space between
the second electrode 600b and the third electrode 600c, and the
fourth wall 510d is received in the annular space between the third
electrode 600c and the fourth electrode 600d. In one embodiment,
the annular spaces between the electrodes 600 are sufficiently
large to allow the walls to slide therein for removal and
installation of the walls 510 in the reaction vessel 204 without
modifying the electrodes 600. If so desired, spacers (not shown)
may be positioned between the walls 510 and the adjacent electrodes
600 to help center the electrodes 600 within their respective
electrode compartments 520.
[0075] The field shaping unit 500 can also include a virtual
electrode unit 530 coupled to the walls 510 of the compartment
assembly for individually shaping the electrical fields produced by
the electrodes 600. In this particular embodiment, the virtual
electrode unit includes first-fourth partitions 530a-530d,
respectively. The first partition 530a can have a first section
532a coupled to the second wall 510b, a skirt 534 depending
downward above the first wall 510a, and a lip 536a projecting
upwardly. The lip 536a has an interior surface 537 that directs the
primary flow F.sub.p exiting from the primary flow guide 400. The
second partition 530b can have a first section 532b coupled to the
third wall 510c and a lip 536b projecting upward from the first
section 532b, the third partition 530c can have a first section
532c coupled to the fourth wall 510d and a lip 536c projecting
upward from the first section 532c, and the fourth partition 530d
can have a first section 532d carried by the outer wall 222 of the
container 220 and a lip 536d projecting upward from the first
section 532d. The fourth partition 530d may simply abut the outer
wall 222 so that the field shaping unit 500 can be quickly removed
from the vessel 204 by simply lifting the virtual electrode unit.
The interface between the fourth partition 530d and the outer wall
222 is sealed by a seal 527 to inhibit both the fluid and the
electrical current from leaking out of the fourth electrode
compartment 520d. The seal 527 can be a lip seal. Additionally,
each of the sections 532a-d can be lateral sections extending
transverse to the common axis.
[0076] In one embodiment, each of the individual partition elements
530a-d are joined together so the virtual electrode unit 530 can be
removed from the reaction vessel as a unit rather than separately
as discrete elements. For example, the individual partitions 530a-d
can be machined from or molded into a single piece of dielectric
material, or they can be individual dielectric members welded or
otherwise joined together. In alternate embodiments, the individual
partitions 530a-d are not attached to each other and/or they can
have different configurations. In the particular embodiment shown
in FIG. 6, the first sections 532a-d of the partitions 530a-d are
annular horizontal members and each of the lips 536a-d are annular
vertical members arranged concentrically.
[0077] The walls 510a-d and the virtual electrode unit 530 are
generally dielectric materials that contain the second flow F.sub.2
of the processing solution for shaping the electric fields
generated by the electrodes 600a-d. The second flow F.sub.2, for
example, can pass (a) through each of the electrode compartments
520a-d, (b) between the individual partitions 530a-d, and then (c)
upward through the annular openings between the lips 536a-d. In
this embodiment, the secondary flow F.sub.2 through the first
electrode compartment 520a can join the primary flow F.sub.p in an
antechamber just before the primary flow guide 400, and the
secondary flow through the second-fourth electrode compartments
520b-d can join the primary flow F.sub.p beyond the top edges of
the lips 536a-d. The flow of electroprocessing solution then flows
over a shield weir attached at rim 538 and into the gap between the
housing 202 and the outer wall 222 of the container 220 as
disclosed in International Application No. PCT/US00/10120. As
explained below with reference to FIG. 6, the fluid in the
secondary flow F.sub.2 can be prevented from flowing out of the
electrode compartments 520a-d to join the primary flow F.sub.p
while still allowing electrical current to pass from the electrodes
600 to the primary flow. In this alternate embodiment, the
secondary flow F.sub.2 can exit the reaction vessel 204 through the
holes 522 in the walls 510 and the hole 525 in the outer wall 222.
In still additional embodiments in which the fluid of the secondary
flow does not join the primary flow, a duct can be coupled to the
exit hole 525 in the outer wall 222 so that a return flow of the
secondary flow passing out of the field shaping unit 500 does not
mix with the return flow of the primary flow passing down the
spiral ramp outside of the outer wall 222.
[0078] The field shaping unit 500 can have other configurations
that are different than the embodiment shown in FIG. 6. For
example, the electrode compartment assembly can have only a single
wall 510 defining a single electrode compartment 520, and the
reaction vessel 204 can include only a single electrode 600. The
field shaping unit of either embodiment still separates the primary
and secondary flows so that the primary flow does not engage the
electrode, and thus it shields the workpiece from the single
electrode. One advantage of shielding the workpiece from the
electrodes 600a-d is that the electrodes can accordingly be much
larger than they could be without the field shaping unit because
the size of the electrodes does not have effect on the electrical
field presented to the workpiece. This is particularly useful in
situations that use consumable electrodes because increasing the
size of the electrodes prolongs the life of each electrode, which
reduces downtime for servicing and replacing electrodes.
[0079] An embodiment of reaction vessel 204 shown in FIG. 6 can
accordingly have a first conduit system for conditioning and
directing the primary fluid flow F.sub.p to the workpiece, and a
second conduit system for conditioning and directing the secondary
fluid flow F.sub.2. The first conduit system, for example, can
include the inlet 320 of the distributor 300; the channel 324
between the base 412 of the primary flow guide 400 and the inclined
cavity 322 of the distributor 300; a plenum between the wall 422 of
the outer baffle 420 and the first wall 510a of the field shaping
unit 500; the primary flow guide 400; and the interior surface 537
of the first lip 536a. The first conduit system conditions the
direction of the primary fluid flow F.sub.p by passing it through
the primary flow guide 400 and along the interior surface 537 so
that the velocity of the primary flow F.sub.p normal to the
workpiece is at least substantially uniform across the surface of
the workpiece. The primary flow F.sub.p and rotation of the
workpiece can accordingly be controlled to dominate the mass
transfer of electroprocessing medium at the workpiece.
[0080] The second conduit system, for example, can include the
plenum 330 and the channels 340-346 of the distributor 300, the
walls 510 of the field shaping unit 500, and the partitions 530a-d
of the field shaping unit 500. The secondary flow F.sub.2 contacts
the electrodes 600 to establish individual electrical fields in the
field shaping unit 500 that are electrically coupled to the primary
flow F.sub.p. The field shaping unit 500, for example, separates
the individual electrical fields created by the electrodes 600a-d
to create "virtual electrodes" at the top of the openings defined
by the lips 536a-d of the partitions. In this particular
embodiment, the central opening inside the first lip 536a defines a
first virtual electrode, the annular opening between the first and
second lips 536a-b defines a second virtual electrode, the annular
opening between the second and third lips 536b-c defines a third
virtual electrode, and the annular opening between the third and
fourth lips 536c-d defines a fourth virtual electrode. These are
"virtual electrodes" because the field shaping unit 500 shapes the
individual electrical fields of the actual electrodes 600a-d so
that the effect of the electrodes 600a-d acts as if they are placed
between the top edges of the lips 536a-d. This allows the actual
electrodes 600a-d to be isolated from the primary fluid flow, which
can provide several benefits as explained in more detail below.
[0081] An additional embodiment of the processing chamber 200
includes at least one interface member 700 (identified individually
by reference numbers 700a-d) for further conditioning the secondary
flow F.sub.2 of electroprocessing solution. The interface members
700, for example, can be filters that capture particles in the
secondary flow that were generated by the electrodes (i.e., anodes)
or other sources of particles. The filter-type interface members
700 can also inhibit bubbles in the secondary flow F.sub.2 from
passing into the primary flow F.sub.p of electroprocessing
solution. This effectively forces the bubbles to pass radially
outwardly through the holes 522 in the walls 510 of the field
shaping unit 500. In alternate embodiments, the interface members
700 can be ion-membranes that allow ions in the secondary flow
F.sub.2 to pass through the interface members 700. The ion-membrane
interface members 700 can be selected to (a) allow the fluid of the
electroprocessing solution and ions to pass through the interface
member 700, or (b) allow only the desired ions to pass through the
interface member such that the fluid itself is prevented from
passing beyond the ion-membrane.
[0082] FIG. 8 is another isometric view of the reaction vessel 204
of FIG. 6 showing a cross-sectional portion taken along a different
cross-section. More specifically, the cross-section of FIG. 6 is
shown in FIG. 10A and the cross-section of FIG. 8 is shown in FIG.
10B. Returning now to FIG. 8, this illustration further shows one
embodiment for configuring a plurality of interface members 700a-d
relative to the partitions 530a-d of the field shaping unit 500. A
first interface member 700a can be attached to the skirt 534 of the
first partition 530a so that a first portion of the secondary flow
F.sub.2 flows past the first electrode 600a, through an opening 535
in the skirt 534, and then to the first interface member 700a.
Another portion of the secondary flow F.sub.2 can flow past the
second electrode 600b to the second interface member 700b.
Similarly, portions of the secondary flow F.sub.2 can flow past the
third and fourth electrodes 600c-d to the third and fourth
interface members 700c-d.
[0083] When the interface members 700a-d are filters or
ion-membranes that allow the fluid in the secondary flow F.sub.2 to
pass through the interface members 700a-d, the secondary flow
F.sub.2 joins the primary fluid flow F.sub.p. The portion of the
secondary flow F.sub.2 in the first electrode compartment 520a can
pass through the opening 535 in the skirt 534 and the first
interface member 700a, and then into a plenum between the first
wall 510a and the outer wall 422 of the baffle 420. This portion of
the secondary flow F.sub.2 accordingly joins the primary flow
F.sub.p and passes through the primary flow guide 400. The other
portions of the secondary flow F.sub.2 in this particular
embodiment pass through the second-fourth electrode compartments
520b-d and then through the annular openings between the lips
536a-d. The second-fourth interface members 700b-d can accordingly
be attached to the field shaping unit 500 downstream from the
second-fourth electrodes 600b-d.
[0084] In the particular embodiment shown in FIG. 8, the second
interface member 700b is positioned vertically between the first
and second partitions 530a-b, the third interface member 700c is
positioned vertically between the second and third partitions
530b-c, and the fourth interface member 700d is positioned
vertically between the third and fourth partitions 530c-d. The
interface assemblies 710a-d are generally installed vertically, or
at least at an upwardly inclined angle relative to horizontal, to
force the bubbles to rise so that they can escape through the holes
522 in the walls 510a-d (FIG. 6). This prevents aggregations of
bubbles that could potentially disrupt the electrical field from an
individual electrode.
[0085] FIGS. 9A and 9B illustrate an interface assembly 710 for
mounting the interface members 700 to the field shaping unit 500 in
accordance with an embodiment of the invention. The interface
assembly 710 can include an annular interface member 700 and a
fixture 720 for holding the interface member 700. The fixture 720
can include a first frame 730 having a plurality of openings 732
and a second frame 740 having a plurality of openings 742 (best
shown in FIG. 9A). The holes 732 in the first frame can be aligned
with the holes 742 in the second frame 740. The second frame can
further include a plurality of annular teeth 744 extending around
the perimeter of the second frame. It will be appreciated that the
teeth 744 can alternatively extend in a different direction on the
exterior surface of the second frame 740 in other embodiments, but
the teeth 744 generally extend around the perimeter of the second
frame 740 in a top annular band and a lower annular band to provide
annular seals with the partitions 536a-d (FIG. 6). The interface
member 700 can be pressed between the first frame 730 and the
second frame 740 to securely hold the interface member 700 in
place. The interface assembly 710 can also include a top band 750a
extending around the top of the frames 730 and 740 and a bottom
band 750b extending around the bottom of the frames 730 and 740.
The top and bottom bands 750a-b can be welded to the frames 730 and
740 by annular welds 752. Additionally, the first and second frames
730 and 740 can be welded to each other by welds 754. It will be
appreciated that the interface assembly 710 can have several
different embodiments that are defined by the configuration of the
field shaping unit 500 (FIG. 6) and the particular configuration of
the electrode compartments 520a-d (FIG. 6).
[0086] When the interface member 700 is a filter material that
allows the secondary flow F.sub.2 of electroprocessing solution to
pass through the holes 732 in the first frame 730, the
post-filtered portion of the solution continues along a path (arrow
Q) to join the primary fluid flow F.sub.p as described above. One
suitable material for a filter-type interface member 700 is
POREX.RTM., which is a porous plastic that filters particles to
prevent them from passing through the interface member. In plating
systems that use consumable anodes (e.g., phosphorized copper or
nickel sulfamate), the interface member 700 can prevent the
particles generated by the anodes from reaching the plating surface
of the workpiece.
[0087] In alternate embodiments in which the interface member 700
is an ion-membrane, the interface member 700 can be permeable to
preferred ions to allow these ions to pass through the interface
member 700 and into the primary fluid flow F.sub.p. One suitable
ion-membrane is NAFION.RTM. perfluorinated membranes manufactured
by DuPont.RTM.. In one application for copper plating, a NAFION 450
ion-selective membrane is used. Other suitable types of
ion-membranes for plating can be polymers that are permeable to
many cations, but reject anions and non-polar species. It will be
appreciated that in electropolishing applications, the interface
member 700 may be selected to be permeable to anions, but reject
cations and non-polar species. The preferred ions can be
transferred through the ion-membrane interface member 700 by a
driving force, such as a difference in concentration of ions on
either side of the membrane, a difference in electrical potential,
or hydrostatic pressure.
[0088] Using an ion-membrane that prevents the fluid of the
electroprocessing solution from passing through the interface
member 700 allows the electrical current to pass through the
interface member while filtering out particles, organic additives
and bubbles in the fluid. For example, in plating applications in
which the interface member 700 is permeable to cations, the primary
fluid flow F.sub.p that contacts the workpiece can be a catholyte
and the secondary fluid flow F.sub.2 that does not contact the
workpiece can be a separate anolyte because these fluids do not mix
in this embodiment. A benefit of having separate anolyte and
catholyte fluid flows is that it eliminates the consumption of
additives at the anodes and the need to replenish the additives as
often. Additionally, this feature combined with the "virtual
electrode" aspect of the reaction vessel 204 reduces the need to
"burn-in" anodes for insuring a consistent black film over the
anodes for predictable current distribution because the current
distribution is controlled by the configuration of the field
shaping unit 500. Another advantage is that it also eliminates the
need to have a predictable consumption of additives in the
secondary flow F.sub.2 because the additives to the secondary flow
F.sub.2 do not effect the primary fluid flow F.sub.p when the two
fluids are separated from each other.
[0089] Referring to FIG. 8 again, the interface assemblies 710a-d
are generally installed so that the interface members 700a-d are
vertical or at least at an upwardly inclined angle relative to
horizontal. The vertical arrangement of the interface assemblies
710a-d is advantageous because the interface members 700 force the
bubbles to rise so that they can escape through the holes 522 in
the walls 510a-d (FIG. 6). This prevents aggregations of bubbles
that could potentially disrupt the electrical field from an
individual anode.
[0090] From time to time, it may be desirable to modify a
particular reaction vessel 204 from a first configuration for
processing a first type of workpiece 5 to a second configuration
for processing a different second type of workpiece 5. For example,
a reaction vessel 204 adapted to treat a first size of workpiece,
e.g., to electroplate a semiconductor wafer having a 300 mm
diameter, is not well suited to treat differently sized workpieces,
e.g., to electroplate 200 mm semiconductor wafers, to yield
consistent, high-quality products. The two types of workpieces need
not be different shapes to merit alteration of the electric field
and/or flow pattern of processing fluid. For example, the
workpieces may require plating of a different material or a
different thickness of the same material, or the workpieces
surfaces may have different conductivities.
[0091] One embodiment of the present invention provides a reaction
vessel 204 which can be easily modified to treat different
workpieces and which can be easily disassembled for access to the
electrodes 600 therein. In this embodiment, at least the virtual
electrode unit 530 of the field shaping unit 500 can be easily
removed from the reaction vessel 204 and replaced with a different
virtual electrode unit adapted for treating a different
workpiece.
[0092] As seen in FIGS. 6 and 8, the outer partition 530d may
simply rest atop the upper edge of the outer wall 222 of the
reaction vessel 204 without being securely affixed thereto. As
noted above, each of the individual partitions 530a-d may be joined
together, enabling the virtual electrode unit 530 to be removed
from the reaction vessel 204 as a unit rather than separately as
discrete elements. In the particular embodiment shown in FIG. 6, an
upper edge of each of the walls 510a-d is coupled to a separate
partition 530a-d, respectively, and the lower edge of each of the
walls 510 may be releasably received in an annular recess 314 in
the distributor 300. The walls 510 may also be slidably received in
annular spaces between adjacent pairs of electrodes 600, as noted
above. As a consequence, the entire field shaping unit 500, not
just the virtual electrode unit 530, may be removed from the
reaction vessel as a unit.
[0093] FIG. 11 illustrates removal of the field shaping unit 500
from the reaction vessel 204. As can be seen in this view, the
virtual electrode unit 530 and the walls 510 (only the outer wall
510d being visible in FIG. 11) of the field shaping unit 500 are
removed from the reaction vessel 204 as a unit. The electrodes 600
remain in place in the reaction vessel, supported by the pillars
(602 in FIG. 6). Removing the field shaping unit 500 in this
fashion allows ready access to the electrodes, e.g., for periodic
inspection and maintenance or for scheduled replacement of
consumable anodes. It also permits replacement of the field shaping
unit 500 with a different field shaping unit better adapted for use
with a different workpiece.
[0094] FIG. 12 is an isometric view of an embodiment of the
processing chamber 200 with a different virtual electrode unit 540
therein. Many features of the processing chamber 200 shown in FIG.
12 can be the same as those described above with reference to FIG.
6, and thus like reference numbers refer to like parts in these
Figures. The primary difference between the embodiment of FIG. 6
and the embodiment of FIG. 12 is that the virtual electrode unit
540 in FIG. 12 defines a different flow pattern than does the
virtual electrode unit 530 of FIG. 6.
[0095] The general structure of the virtual electrode units 530 and
540 are similar. Hence, the virtual electrode unit 540 of FIG. 12
includes first-fourth partitions 540a-540d, respectively. The first
partition 540a can have a first section 542a coupled to the second
wall 510b, a skirt 544 depending downward above the first wall
510a, and a lip 546a projecting upwardly. The lip 546a has an
interior surface 547 that directs the primary flow F.sub.p exiting
from the primary flow guide 400. The second partition 540b can have
a first section 542b coupled to the third wall 510c and a lip 546b
projecting from the first section 542b, the third partition 540c
can have a first section 542c coupled to the fourth wall 510d and a
lip 546c projecting upward from the first section 542c, and the
fourth partition 540d can have a first section 542d which engages
the outer wall 222 of the container 220 and a lip 546d projecting
from the first section 542d. As with the virtual electrode unit 530
described above, the partitions 540a-d may be joined together so
the virtual electrode unit 540 can be removed from the reaction
vessel as a unit. In the particular embodiment shown in FIG. 12,
the first sections 542a-d of the partitions 540a-d are annular
horizontal members and each of the lips 546a-d are annular vertical
members that are arranged concentrically.
[0096] The two virtual electrode units 530 and 540 functionally
differ in that the partitions 540a-d in FIG. 12 define gaps between
adjacent lips 546 having different relative positions with respect
to the common axis A-A from the gaps defined between adjacent lips
536 of the partitions 530a-d in FIG. 6. As explained above, these
gaps may define the discharge outlets for the processing fluid and,
hence, the relative positions and sizes of the virtual electrodes.
As a practical matter, these virtual electrodes define the shape of
the electrical field in the processing fluid. As a consequence,
replacing the virtual electrode unit 530 of FIG. 6 with the virtual
electrode unit 540 of FIG. 12 will alter the effective electrical
field adjacent the workpiece. Comparing FIGS. 6 and 12, it can be
seen that the first sections 542a-d and lips 546a-d of partitions
540a-d in FIG. 12 are longer than the first sections 532a-d and
lips 536a-d of partitions 530a-d in FIG. 6. As a result, the
virtual electrodes defined by the virtual electrode unit 540 are
positioned higher within and closer to the common axis A-A of the
reaction vessel 204 than the virtual electrodes of FIG. 6. The
processing chamber 200 of FIG. 12 with virtual electrode unit 540
may be better adapted for use with a smaller workpiece than is the
processing chamber 200 of FIG. 6 with virtual electrode unit
530.
[0097] The walls 510 in FIG. 12 are received in the same spaces
between adjacent electrodes 600 as are the walls 510 in FIG. 6. In
one embodiment, the virtual electrode units 530 and 540 merely abut
the walls 510, but the walls 510 remain in place when either of the
virtual electrode units are removed. In such an embodiment, the
virtual electrode units 530 and 540 may have recesses or abutments
at the same relative positions so that they will abut the upper
edges of the walls 510 when one virtual electrode unit replaces the
other. This enables one to alter the electric field in the
processing chamber 200 without altering any other parts of the
processing chamber. In an alternative embodiment, the walls 510 are
coupled to the virtual electrode unit 540 and the field shaping
unit 502 may be removed as a unit. This would be directly analogous
to the embodiment shown in FIG. 11, with the field shaping unit 502
of FIG. 12 being readily substitutable for the field shaping unit
500 of FIG. 6. To ensure that the walls 510 are properly arranged
to be received in the annular spaces between adjacent electrodes
600, the relative positions of the walls 510 of the field shaping
unit 502 (FIG. 12) may be the same as the relative positions of the
walls 510 of the field shaping unit 500 (FIG. 6).
[0098] C. Methods of Treating Different Workpieces with the Same
Electrochemical Processing Chamber
[0099] As noted above, certain embodiments of the present invention
provide methods enabling a single electrochemical processing
chamber to be used to treat different workpieces. In the following
discussion of different embodiments of these methods, reference is
made to the processing chambers 200 shown in FIGS. 6 and 12. It
should be understood that this is solely for purposes of
convenience, however, and that various methods of the invention may
be carried out with processing chambers which differ from those
illustrated in these drawings or which do not include all of the
detailed features shown in the drawings.
[0100] One embodiment of the invention provides a method for
modifying an electrochemical processing chamber 200 from a first
configuration for treating a first workpiece 101 (shown in FIG. 3)
to a second configuration for treating a different second workpiece
101a (shown in FIG. 13). The second workpiece 101a may differ from
the first in terms of size (as in the illustrated embodiment),
electrical properties, or a variety of other features, as noted
above. An electrochemical processing chamber 200 is initially
configured to treat the first workpiece 101. For example, the
electrochemical processing chamber 200 of FIG. 6 may include a
first virtual electrode unit 530 which defines a plurality of
virtual electrodes sized and positioned to electroplate a metal on
a particular type of workpiece, e.g., a 300 mm semiconductor wafer.
One of these workpieces will be positioned in the contact assembly
160 (FIG. 3) and the contact assembly 160 may be positioned over
the reaction vessel 204 with a surface of the workpiece in contact
with a processing solution in the reaction vessel 204. The
workpiece may then be treated with the electrochemical processing
chamber 200. When using the apparatus shown in FIG. 6, this could
include delivering a primary fluid flow F.sub.p through the first
inlet 320 and delivering a secondary fluid flow F.sub.2 through the
plenum 330. An electrical potential may be applied to the
electrodes 600 and the secondary fluid flow F.sub.2 may pass
through the electrode compartments 320a-d, through the discharge
openings defined by the virtual electrode unit 530, and into
electrical contact with the primary fluid flow F.sub.p.
[0101] After the first workpiece 101 is treated, the
electrochemical processing chamber 200 may be modified to treat a
different second workpiece 101a, e.g., a 200 mm semiconductor
wafer. As suggested in FIG. 11, this may be achieved by lifting the
contact assembly 160 and removing the initial virtual electrode
unit 530 of FIG. 6 from the reaction vessel 204. Thereafter, a
different virtual electrode unit 540 (FIG. 12) may be installed in
the reaction vessel. In one embodiment, the initial virtual
electrode unit 530 is removed as a unit, but the walls 510 remain
in place. The second virtual electrode unit 540 may then be
installed by placing it atop the upper edges of the same walls 510.
In an alternative embodiment, the walls 510 are coupled to the
first virtual electrode unit 530 and the entire field shaping unit
500 of FIG. 6 is removed as a unit. Thereafter, the second field
shaping unit 502 may be installed in the reaction vessel 204,
yielding an electrochemical processing chamber 200 essentially as
shown in FIG. 12. When installing the second field shaping unit 502
in the reaction vessel 204, the walls 510 of the second field
shaping unit 502 may be inserted in the annular spaces between
adjacent electrodes previously occupied by the walls 510 of the
first field shaping unit 500. Similarly, the lower edges of the
walls 510 of the second field shaping unit 502 may be positioned in
the annular recesses 314 in the distributor 310 previously occupied
by lower edges of the walls 510 of the first field shaping unit
500.
[0102] After the electrochemical processing chamber 200 has been
adapted for treating the second type of workpiece, one of the
second workpieces may be treated with the modified electrochemical
processing chamber 200. The process may substantially parallel that
outlined above in connection with treating the first workpiece.
Depending on the nature of the contact assembly 160 being used and
the differences between the workpieces, it may be necessary to
replace the contact assembly 160 used to treat the first workpiece
101 with a different contact assembly 161 better suited to handle
the second type of workpiece 101a. FIG. 13 schematically
illustrates the electrochemical processing chamber of FIG. 3
modified for use with a smaller second workpiece 101a. In FIG. 13,
the contact assembly 160 of FIG. 3 has been replaced with a smaller
contact assembly 161 sized to accommodate the smaller workpiece
101a carried thereby. The rotor 154 and backing plate 155 of FIG. 3
may also replaced with like components better adapted to mate with
the smaller contact assembly 161. Once the second workpiece 101a is
properly positioned in an appropriate contact assembly 161, the
contact assembly 161 may be positioned over the reaction vessel 204
with a surface of the workpiece in contact with a processing
solution, the primary and secondary fluid flows F.sub.p and F.sub.2
may be established and power may be applied to the electrodes 600,
as outlined above in connection with treatment of the first
workpiece.
[0103] As noted above, the virtual electrodes defined by the first
virtual electrode unit 530 (FIG. 6) may be sized and shaped to
optimize electrochemical processing for the first workpiece and the
virtual electrodes defined by the second virtual electrode unit 540
(FIG. 12) may be sized and shaped to optimize electrode chemical
processing for the second workpiece. Simply by replacing the first
field shaping unit 500 with the second field shaping unit 502
thereby permits the same electrochemical processing chamber 200 to
be optimized for treating two different workpieces without
necessitating modification of the electrodes 600 in the reaction
vessel 204. This is indirect contrast to conventional single wafer
processing chambers 1 such as that shown in FIG. 1, wherein
attempting to adapt the processing chamber for use with differently
sized workpieces would necessitate significant modifications. These
modifications would include removing the anode 4 and primary flow
guide 6 and replacing them with new, different parts. The
electrical connection of the anode 4 to its power supply can
complicate this exchange, particularly as compared to the simple
modification process afforded by this embodiment of the present
invention.
[0104] Another embodiment of the present invention permits a
manufacturer to effectuate electrochemical treatment of two
different workpieces by providing an initial electrochemical
processing chamber 200 and a second virtual electrode unit 540 and
giving the user appropriate instructions. The initial
electrochemical processing chamber 200 may be substantially the
same as that shown in FIG. 6 and include a virtual electrode unit
530 optimized for treating the first workpiece. The second virtual
electrode unit 540 may define virtual electrodes having predefined
relative positions optimized for treating the second workpiece. The
user may be instructed to treat the first workpiece with the
initial electrochemical processing chamber 200; to replace the
first virtual electrode unit 530 with the second virtual electrode
unit 540, thereby modifying the initial electrochemical processing
chamber by repositioning the virtual electrodes without necessity
of altering the electrodes of the reaction vessel; and to treat the
second workpiece with the modified electrochemical processing
chamber. The user may be instructed in any appropriate way. This
may include written communication such as a written instruction
manual, hands-on training, and/or videotaped instruction, for
example.
[0105] An alternative embodiment of the invention provides a method
of effectuating assembly of an electrochemical processing chamber
200. This embodiment includes providing a reaction vessel 204
having an outer wall 222, a plurality of electrodes (e.g., 600a and
600b), and a wall-receiving space between adjacent electrodes. A
replaceable first field shaping unit (e.g., the field shaping unit
500 of FIG. 6) is provided. The first field shaping unit 500 has at
least one wall (e.g., wall 510b) adapted to be received in the
wall-receiving space between the electrodes 600. The first field
shaping unit has a first virtual electrode unit 530 coupled to the
wall 510. The first virtual electrode unit 530 defines a first set
of virtual electrodes (e.g., VE.sub.1 and VE.sub.2) having
predefined relative positions. A second field shaping unit 500
(e.g., the one shown in FIG. 8) is provided, with the second field
shaping unit 500 also having at least one wall (e.g., wall 510b)
adapted to be received in the wall-receiving space between the
electrodes 600. The second field shaping unit 500 has a second
virtual electrode unit 540 coupled to the wall 510 and defining a
second set of virtual electrodes (e.g., VE.sub.1 and VE.sub.2)
having predefined relative positions.
[0106] At least one functional characteristic of the first field
shaping unit 500 is identified and at least one functional
characteristic of the second field shaping unit 500 is identified.
The identified functional characteristic of the first field shaping
unit 500 is different from the identified functional characteristic
of the second field shaping unit 500. For example, the first field
shaping unit 500 may be identified as being adapted for use with a
particular size of workpiece, such as a 300 mm semiconductor wafer,
and the second field shaping unit may be identified as being
adapted for use with a different size of workpiece, such as a 200
mm semiconductor wafer. This identifying information may enable a
user to select between the first and second field shaping units to
adapt the reaction vessel to treat a selected type of
workpiece.
[0107] From the foregoing, it will be appreciated that specific
embodiments of the invention have been described herein for
purposes of illustration, but that various modifications may be
made without deviating from the spirit and scope of the invention.
Accordingly, the invention is not limited except as by the appended
claims.
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