U.S. patent application number 10/172534 was filed with the patent office on 2003-12-18 for electro-magnetic configuration for uniformity enhancement in a dual chamber plasma processing system.
This patent application is currently assigned to Applied Materials, Inc.. Invention is credited to Bach, Joseph, Pan, Shaoher X..
Application Number | 20030230385 10/172534 |
Document ID | / |
Family ID | 29733086 |
Filed Date | 2003-12-18 |
United States Patent
Application |
20030230385 |
Kind Code |
A1 |
Bach, Joseph ; et
al. |
December 18, 2003 |
Electro-magnetic configuration for uniformity enhancement in a dual
chamber plasma processing system
Abstract
Embodiments of the invention provide a tandem magnetically
enhanced etch chamber. The tandem chamber generally includes a
first tandem processing chamber, a second tandem processing chamber
positioned adjacent the first tandem processing chamber and being
partially separated therefrom by a shared central wall, and a
pumping apparatus cooperatively in fluid communication with the
first and second chambers. The first tandem processing chamber
generally includes a first substrate support member positioned in a
first chamber, a first plasma generation device in communication
with the first chamber, and a plurality of first selectively
actuated electromagnets positioned around the first chamber. The
second tandem processing chamber generally includes a second
substrate support member positioned in a second chamber, a second
plasma generation device in communication with the second chamber,
and a plurality of second selectively actuated electromagnets
positioned around the second chamber.
Inventors: |
Bach, Joseph; (Morgan Hill,
CA) ; Pan, Shaoher X.; (San Jose, CA) |
Correspondence
Address: |
APPLIED MATERIALS, INC.
2881 SCOTT BLVD. M/S 2061
SANTA CLARA
CA
95050
US
|
Assignee: |
Applied Materials, Inc.
|
Family ID: |
29733086 |
Appl. No.: |
10/172534 |
Filed: |
June 13, 2002 |
Current U.S.
Class: |
156/345.49 ;
156/345.28; 156/345.31 |
Current CPC
Class: |
H01L 21/67017 20130101;
H01L 21/6719 20130101; H01L 21/67207 20130101; H01J 37/3266
20130101; H01J 37/32009 20130101; H01L 21/67069 20130101 |
Class at
Publication: |
156/345.49 ;
156/345.31; 156/345.28 |
International
Class: |
C23F 001/00 |
Claims
1. A tandem magnetically enhanced etching chamber, comprising: a
first tandem processing chamber defining a first processing region,
comprising: a first substrate support member positioned in a first
chamber; a first plasma generation device in communication with the
first chamber; and a plurality of first selectively actuated
electromagnets positioned around the first chamber; a second tandem
processing chamber positioned adjacent the first tandem processing
chamber, the second tandem processing chamber defining a second
processing region that is partially isolated therefrom by a shared
central wall, the second tandem processing chamber comprising: a
second substrate support member positioned in a second chamber; a
second plasma generation device in communication with the second
chamber; and a plurality of second selectively actuated
electromagnets positioned around the second chamber; a pumping
apparatus cooperatively in fluid communication with the first and
second chambers; and a magnetic shield member positioned between
the first tandem processing chamber and the second tandem
processing chamber.
2. The tandem chamber of claim 1, further comprising a system
controller in electrical communication with the plurality of first
selectively actuated electromagnets and the plurality of second
selectively actuated electromagnets, the system controller being
configured to control the magnitude and duration of the magnetic
field generated by each of the plurality of first selectively
actuated electromagnets and the plurality of second selectively
actuated electromagnets.
3. The tandem chamber of claim 1, wherein the first and second
plurality of selectively actuated electromagnets each comprise four
electromagnets equally positioned around the respective tandem
processing chamber.
4. The tandem chamber of claim 1, wherein the shared central wall
separates an upper portion of the respective first and second
tandem processing chambers, while allowing a lower portion of the
respective first and second tandem processing chamber to be in
fluid communication with each other.
5. The tandem chamber of claim 1, wherein the first and second
plasma generation devices comprise a torroidal plasma conduit
assembly.
6. The tandem chamber of claim 5, wherein the torroidal plasma
conduit assembly comprises: at least one torroidal plasma conduit
in fluid communication with opposing sides of a processing region;
at least one coil positioned proximate the at least one torroidal
plasma conduit; and a power supply in electrical communication with
the at least one coil.
7. The tandem chamber of claim 6, wherein the at least one
torroidal plasma conduit comprises a first and second torroidal
plasma conduits, each of the first and second torroidal plasma
conduits having terminating ends that are in communication with
opposing sides of the processing region.
8. The tandem chamber of claim 6, wherein the power supply
comprises an RF power supply and the at least one coil comprises an
individual coil wound around each of the at least one torroidal
plasma conduits.
9. The tandem chamber of claim 1, further comprising at least one
power supply in electrical communication with the first and second
substrate support members.
10. The tandem chamber of claim 1, further comprising a magnetic
shield member positioned between the first and second tandem
processing regions, the magnetic shield member being configured to
magnetically isolate a first processing region in the first tandem
processing chamber from a second processing region in the second
tandem processing chamber.
11. An etch processing system, comprising: a loadlock chamber; a
substrate transfer chamber selectively in communication with the
loadlock chamber; and at least one tandem etch processing chamber
selectively in communication with the substrate transfer chamber,
the tandem etch chamber comprising: a first and second adjacently
positioned processing chambers; a plurality of electromagnets
positioned around the first and second processing regions; and at
least one torroidal conduit in communication with each of the first
and second adjacently positioned processing chambers, wherein the
first and second adjacently positioned processing chambers share a
common wall that magnetically separates the respective processing
chambers while allowing fluid communication therebetween.
12. The etch processing system of claim 11, wherein the first and
second adjacently positioned processing chambers each comprise a
selectively actuated substrate support member configured to move
between a processing position and a loading position, wherein the
loading position corresponds to a position in a lower portion of
the respective chamber adjacent an aperture configured to
communicate substrates into and out of the chamber, and wherein the
processing position corresponds to a position in an upper portion
of the respective chamber adjacent the plurality of
electromagnets.
13. The etch processing system of claim 11, wherein the plurality
of electromagnets are positioned around an upper portion of the
first and second adjacently positioned processing chambers.
14. The etch processing system of claim 13, wherein a lower portion
of the first and second adjacently positioned processing chambers
includes a selectively actuated valve configured to communicate
substrates therethrough into the lower portion of the first and
second adjacently positioned processing chambers.
15. The etch processing system of claim 11, wherein the plurality
of electromagnets comprise a plurality of individually controlled
electromagnets, each of the plurality of individually controlled
electromagnets being in electrical communication with a system
controller configured to control the magnitude and duration of the
magnetic field generated by each of the plurality of individually
controlled electromagnets.
16. The etch processing system of claim 11, wherein the substrate
transfer chamber includes a substrate handler positioned therein,
the substrate handler being configured to transfer substrates two
at a time between the at least one tandem etch processing chamber
and the loadlock chamber.
17. The etch processing system of claim 11, wherein the at least
one torroidal conduit comprises: a first torroidal conduit having a
first and second terminating ends, the first terminating end being
in communication with a first aperture in communication with a
processing region at a first location, the second terminating end
being in communication with a second aperture in communication with
the processing region at a second location, the second location
being positioned opposite the first location; a second torroidal
conduit having a third and fourth terminating ends, the third
terminating end being in communication with a third aperture in
communication with a processing region at a third location, the
fourth terminating end being in communication with a fourth
aperture in communication with the processing region at a fourth
location, the third location being positioned opposite the fourth
location and equidistant between the first and second locations;
and a coil assembly positioned proximate the first and second
conduits, the coil assembly being configured to generate a field in
the first and second conduits sufficient to ignite a plasma
therein.
18. The etch processing system of claim 17, wherein the coil
assembly comprises a first coil wrapped around the first torroidal
conduit and a second coil wrapped around the second torroidal
conduit, the first and second coils being in electrical
communication with at least one power supply.
19. The etch processing system of claim 11, wherein the at least
one torroidal conduit includes a gas inlet configured to supply a
process gas to the at least one torroidal conduit.
20. The etch processing system of claim 11, wherein the at least
one torroidal conduit comprises at least 3 torroidal conduits in
communication with each of the first and second adjacently
positioned processing chambers, each of the at least 3 torroidal
conduits having terminating ends in fluid communication with the
processing chambers on opposing sides, the terminating ends being
equally spaced radially around a perimeter of the processing
chambers.
21. A tandem processing chamber, comprising: a first processing
chamber, comprising: a first substrate support member configured to
receive a substrate in a lower portion of the first processing
chamber and communicate the substrate to an upper portion of the
first processing chamber for processing; a first plurality of
electronically controlled electromagnets positioned around a
perimeter of the upper portion of the first processing chamber; at
least one first torroidal plasma conduit in fluid communication
with the upper portion of the first processing chamber; and at
least one first coil positioned proximate the at least one first
torroidal plasma conduit and being configured to generate a field
within the at least one first torroidal plasma conduit; a second
processing chamber positioned adjacent the first processing chamber
and sharing a common wall therewith, the second processing chamber
comprising: a second substrate support member configured to receive
a substrate in a lower portion of the second processing chamber and
communicate the substrate to an upper portion of the second
processing chamber for processing; a second plurality of
electronically controlled electromagnets positioned around a
perimeter of the upper portion of the second processing chamber; at
least one second torroidal plasma conduit in fluid communication
with the upper portion of the second processing chamber; and at
least one second coil positioned proximate the at least one second
torroidal plasma conduit and being configured to generate a field
within the at least one second torroidal plasma conduit; at least
one power supply in electrical communication with the at least one
first coil and the at least second first coil; and a system
controller in electrical communication with the power supply, the
system controller being configured to regulate the electrical power
delivered to the at least one first coil and the at least one
second coil.
22. The tandem processing chamber of claim 21, wherein the common
wall is configured to magnetically isolate a first processing
region in the first processing chamber from a second processing
region in the second processing chamber, while allowing fluid
communication between the respective processing regions.
23. The tandem processing chamber of claim 21, wherein the system
controller comprises a microprocessor-type controller configured to
generate control signals for the tandem processing chamber in
accordance with a semiconductor processing recipe.
24. The tandem processing chamber of claim 21, wherein the at least
one first and second torroidal plasma conduits each comprise a pair
of torroidal conduits in fluid communication at terminating ends
with the respective processing regions.
25. The tandem processing chamber of claim 24, wherein the
terminating ends are equally spaced radially around the perimeter
of the upper portion of the first and second processing
chambers.
26. The tandem processing chamber of claim 21, wherein the first
and second plurality of electronically controlled electromagnets
are configured to generate a time varying magnetic field in the
first and second processing chambers in cooperation with the system
controller.
27. The tandem processing chamber of claim 21, wherein the at least
one power supply comprises an RF power supply.
28. The tandem processing chamber of claim 21, wherein the first
and second plurality of electronically controlled electromagnets
each comprise 4 arc shaped electromagnets configured to be
positioned around a perimeter of a processing chamber.
29. The tandem processing chamber of claim 21, wherein first
terminating ends of the at least one first torroidal plasma conduit
are in communication with a first processing region through a
sidewall portion of the tandem processing chamber, and wherein
second terminating ends of the at least one second torroidal plasma
conduit are in communication with a second processing region
through a sidewall portion of the tandem processing chamber.
30. The tandem processing chamber of claim 21, wherein first
terminating ends of the at least one first torroidal plasma conduit
are in communication with a first processing region through a top
portion of the tandem processing chamber, and wherein second
terminating ends of the at least one second torroidal plasma
conduit are in communication with a second processing region
through a top portion of the tandem processing chamber.
31. The tandem processing chamber of claim 21, wherein the at least
one first and second torroidal plasma conduits each include a
process gas inlet configured to supply a process gas to an interior
portion of the at least one first and second torroidal plasma
conduits.
32. The tandem processing chamber of claim 21, further comprising a
centrally located pumping aperture in communication with a vacuum
pump, the centrally located pumping aperture being configured to
simultaneously pump both the first and second processing chambers
to an equal pressure.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] Embodiments of the invention generally relate to
semiconductor processing, and more particularly, to etch and
inductive plasma related semiconductor manufacturing processes and
related hardware.
[0003] 2. Description of the Related Art
[0004] Integrated circuit (IC) substrate processing systems, and in
particular, substrate processing systems configured to fabricate
VLSI and/or ULSI circuits on silicon substrates, often utilize
several processes in order to form the desired circuit features
into a die on a substrate. One process generally used in the
manufacture of semiconductor devices is an etch process, which may
be conducted in a reactive ion etching (RIE) chamber or a
magnetically enhanced reactive ion etching (MERIE) chamber, for
example. RIE and MERIE chambers are generally effective in etching
narrow features into layers formed on a substrate, and therefore,
RIE and MERIE chambers are generally preferred for VLSI and ULSI
applications.
[0005] In an MERIE chamber, for example, features may be etched
into a layer formed on a semiconductor substrate via the generation
of a reactive plasma configured to react with a material on the
substrate surface or the substrate surface itself though a series
of photoresist masks. The reactive plasma is generated via the
introduction of a reactive gas into the chamber, generally via a
showerhead and blocker plate assembly, along with the application
of sufficient energy, generally RF energy, to ignite a plasma of
the reactive gas. A rotating magnetic field, generally produced by
a bank of rotating magnets mounted outside and above the MERIE
chamber, may operate to stir the ignited plasma in order to
generate more uniform plasma characteristics over the entire
substrate surface. However, although the density of the reactive
plasma generated in conventional MERIE systems is sufficient for
etching, it is desired to provide a more dense plasma for some etch
processes.
[0006] In response to the need for a high density plasma in etch
processes, an externally excited torroidal plasma source was added
to an etch chamber. For example, U.S. Pat. No. 6,348,126, which is
incorporated herein by reference, illustrates a torroidal plasma
source in communication with an etch chamber. The torroidal plasma
source operates to communicate a plasma to the processing region,
and is generally capable of generating a plasma having a higher
density than plasmas generated by conventional MERIE chambers.
[0007] However, another challenge associated with conventional
semiconductor etch systems is that they are generally configured as
single chamber, single substrate-type chambers, i.e., a single
chamber is used to conduct an etch process on a single substrate in
a one-at-a-time-type fashion. These single chamber-type systems are
not able to provide high throughput rates, as each substrate must
be sequentially processed in the single chamber. In order to
address the throughput issues of single chamber-type systems, batch
etch processing-type chambers have been developed. However,
batch-type systems have been found to be generally undesirable in
semiconductor manufacturing etch processes, as batch etch-type
systems have been shown to yield uniformity variations between
substrates manufactured in the same batch. Additionally, in other
semiconductor processing areas, such as, for example, chemical
vapor deposition, tandem processing chambers have been utilized to
provide improved throughput while maintaining yield uniformity. For
example, U.S. Pat. No. 6,152,070, which is assigned to Applied
Materials of Santa Clara, Calif., illustrates a tandem processing
chamber that may be used for vacuum processing of two substrates in
separate isolated tandem processing regions at the same time. The
tandem processing chambers may be accessed simultaneously by a
single dual robot blade configured to insert and/or remove
substrates from both of the processing regions at the same time.
However, conventional semiconductor processing apparatuses and
methods generally do not provide an etch chamber capable of
providing greater throughput than that provided by single substrate
chambers without sacrificing the physical characteristics, such as
uniformity, for example, of the substrates produced.
[0008] Therefore, there is a need for an etch chamber configured to
provide controllable etch uniformity and improved throughput
characteristics.
SUMMARY OF THE INVENTION
[0009] Embodiments of the invention generally provide an etch
system configured to provide concurrent transfer of at least two
substrates through the etch system simultaneously. The substrates
may be processed concurrently in tandem chambers that share common
gas supply and pumping systems. Each of the tandem chambers
generally includes a processing region having a substrate support
member positioned therein, wherein the substrate support member may
include heating and/or cooling elements to maintain a desired
substrate temperature during processing. Additionally, each of the
tandem chambers includes devices configured to generate and control
a plasma in each of the respective tandem chambers, as well as a
shield member positioned between the respective chambers to prevent
magnetic interference. Accordingly, the present etch system is
capable of providing the process control features of single
substrate etch processing systems, while also providing increased
substrate throughput.
[0010] More particularly, embodiments of the invention provide a
tandem magnetically enhanced inductive source chamber for a
semiconductor processing system. The tandem chamber generally
includes a first tandem processing chamber, a second tandem
processing chamber positioned adjacent the first tandem processing
chamber and being separated therefrom by a shared central wall, and
a pumping apparatus cooperatively in fluid communication with the
first and second chambers. The first tandem processing chamber
generally includes a first substrate support member positioned in a
first chamber, a first plasma generation device in communication
with the first chamber, and a plurality of first selectively
actuated electromagnets positioned around the first chamber. The
second tandem processing chamber generally includes a second
substrate support member positioned in a second chamber, a second
plasma generation device in communication with the second chamber,
and a plurality of second selectively actuated electromagnets
positioned around the second chamber.
[0011] Embodiments of the invention further provide a magnetically
enhanced inductive source processing system that includes a
loadlock chamber, a substrate transfer chamber selectively in
communication with the loadlock chamber, and at least one tandem
processing chamber selectively in communication with the substrate
transfer chamber. The at least one tandem chamber generally
includes a first and second adjacently positioned isolated
processing chambers, a plurality of electromagnets positioned
around the first and second processing regions, and at least one
torroidal conduit in communication with each of the first and
second adjacently positioned processing chambers. Additionally, the
first and second adjacently positioned processing chambers
generally share a common wall that magnetically separates the
respective processing chambers while allowing fluid communication
therebetween.
[0012] Embodiments of the invention further provide a tandem
processing chamber having a first processing chamber, a second
processing chamber positioned adjacent the first processing chamber
and sharing a common wall therewith, at least one power supply in
electrical communication with a first coil and a second coil, and a
system controller in electrical communication with the power
supply, the system controller being configured to regulate the
electrical power delivered to the first and second coils. The first
processing chamber includes a first substrate support member
configured to receive a substrate in a lower portion of the first
processing chamber and communicate the substrate to an upper
portion of the first processing chamber for processing, and a first
plurality of electronically controlled electromagnets positioned
around a perimeter of the upper portion of the first processing
chamber. Additionally, the first processing chamber generally
includes at least one first torroidal plasma conduit in fluid
communication with the upper portion of the first processing
chamber, and at least one first coil positioned proximate the at
least one first torroidal plasma conduit and being configured to
generate a field within the at least one first torroidal plasma
conduit. The second processing chamber generally includes a second
substrate support member configured to receive a substrate in a
lower portion of the second processing chamber and communicate the
substrate to an upper portion of the second processing chamber for
processing and a second plurality of electronically controlled
electromagnets positioned around a perimeter of the upper portion
of the second processing chamber. Additionally, the second
processing chamber generally includes at least one second torroidal
plasma conduit in fluid communication with the upper portion of the
second processing chamber, and at least one second coil positioned
proximate the at least one second torroidal plasma conduit and
being configured to generate a field within the at least one second
torroidal plasma conduit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] So that the manner in which the above-recited features of
the invention are obtained may be understood in detail, a more
particular description of the invention briefly summarized above
may be had by reference to the embodiments thereof, which are
illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only typical embodiments of
this invention, and are therefore, not to be considered limiting of
its scope, for the invention may admit to other equally effective
embodiments.
[0014] FIG. 1 illustrates a plan view of an embodiment of the etch
system of the invention.
[0015] FIG. 2A illustrates a sectional view of an embodiment of a
tandem etch chamber of the invention.
[0016] FIG. 2B illustrates a sectional view of another embodiment
of a tandem etch chamber of the invention.
[0017] FIG. 3 illustrates a plan view of an exemplary tandem
processing chamber of the invention.
[0018] FIG. 4 illustrates a plan view of another exemplary tandem
processing chamber of the invention.
[0019] FIG. 5 illustrates a plan view of another exemplary tandem
processing chamber of the invention.
[0020] FIG. 6 illustrates a sectional view of an alternative
embodiment of the tandem processing chamber of the invention.
[0021] FIG. 7A illustrates a plan view of dense plasma regions
within tandem processing chambers of the invention.
[0022] FIG. 7B illustrates a plan view of magnetic field lines in a
tandem processing chamber of the invention.
[0023] FIG. 7C illustrates a plan view of magnetic field lines in
another tandem processing chamber of the invention.
[0024] FIG. 8 illustrates a sectional view of an exemplary tandem
processing chamber of the invention.
[0025] FIG. 9 illustrates a tandem etch processing chamber having
cantilever-type substrate support members.
[0026] FIG. 10 illustrates a tandem etch processing chamber having
rotatable magnets positioned above the lid of the chamber.
[0027] FIGS. 11A-11D illustrate an exemplary plasma stirring
process that may be implemented by embodiments of the
invention.
DETAILED DESCRIPTION
[0028] FIG. 1 illustrates a plan view of an exemplary tandem
chamber-type etch platform 100 of the invention. Platform 100 is
generally a self-contained system having the necessary processing
utilities supported on a main frame structure that can be easily
installed and provides a quick start up for operation. System 100
generally includes four different regions, namely, a front end
staging area 102, a loadlock chamber 112, and a transfer chamber
104 in communication with a plurality of tandem processing chambers
106 via isolation valves 209. Front end staging area 102, which is
generally known as a factory interface or mini environment,
generally includes an enclosure having at least one substrate
containing cassette 109 positioned in communication therewith via a
pod loader configuration. A front end substrate transfer robot 113,
which may generally be a track robot configured to move
longitudinally within the enclosure, is generally positioned
proximate cassettes 109 and is configured to remove substrates
therefrom for processing, as well as position substrates therein
once processing of the substrates is complete. Although four
cassettes are shown, the present invention is not limited to any
particular number of cassettes. For example, embodiments of the
invention contemplate using the two outermost substrate cassette
positions/pod loaders, while replacing the two interior cassette
positions/pod loaders with a stackable substrate cassette feeder
assembly (not shown). The stackable substrate feeder assembly may
be configured to store a plurality of substrate cassettes in a
vertical stack and individually deliver the cassettes to the outer
cassette locations/pod loaders when needed. The front end staging
area 102 is selectively in communication with the load lock chamber
112 through, for example, a selectively actuated valve (not shown).
Additionally, loadlock 112 may also be selectively in communication
with the transfer chamber 104 via another selectively actuated
valve, for example. Therefore, the loadlock chamber 112 may operate
to isolate the interior of the substrate transfer chamber 104 from
the interior of the front end enclosure 102 during the process of
transferring one or more substrates into the transfer chamber 104
for processing. Loadlock chamber 112 may be a side-by-side
substrate type chamber, a single substrate type chamber, or
multi-substrate-type loadlock chamber, for example, as is generally
known in the art.
[0029] A substrate handler 105 may be centrally positioned in the
interior portion of the transfer chamber 104. Substrate handler 105
is generally configured to receive substrates from the loadlock
chamber 112 and transport the substrates received therefrom to one
of the processing chambers 106 positioned about the perimeter of
the transfer chamber 106. Additionally, substrate handler 105 is
generally configured to transport substrates between the respective
processing chambers 106, as well as from the processing chambers
106 back into the loadlock chamber 112. The substrate handler 105
generally includes a dual blade configured to support two
substrates thereon simultaneously. Additionally, the blade of
substrate handler 105 is selectively extendable, while the base is
rotatable, which allows the blade to access the interior portion of
any of the processing chambers 106, the loadlock chamber 112,
and/or any other chamber positioned around the perimeter of the
transfer chamber 104. A utility supply unit (not shown), which may
be positioned in any location that is generally proximate system
100, generally houses the support utilities needed for operation of
system 100, such as a gas panel, a power distribution panel, power
generators, and other components used to support semiconductor etch
processes.
[0030] FIG. 2A illustrates a sectional view of an exemplary
processing chamber 106 of the invention, which may be a tandem
magnetically enhanced etch chamber, for example. Processing chamber
106 generally provides a tandem process chamber configuration,
wherein each of the tandem process chambers 200, 201 includes an
individual processing region 202, 203 therein. Each of the
respective tandem process chambers 200, 201 includes sidewalls 205,
a common interior wall 206, and a bottom 207. The interior wall 206
may generally be a shared central wall that separates the upper
portion of the respective chambers 200, 201 from each other. As
such, the processing regions 202, 203 defined in the respective
chambers 200, 201 may not be in line of sight contact, but may
share a common pressure, as the lower portion of wall 206 may allow
the respective chambers 200, 201 to communicate with each other. A
substrate support member 208, which may include a substrate lift
pin assembly 212, may be positioned within each of the respective
processing chambers 200, 201 via extension into chambers 200, 201
through bottom 207. The substrate support members 208 may be
movable in a vertical direction, i.e., in the direction along the
axis of the supporting stem member, and may be heated and/or cooled
through, for example, fluid conduits formed therein or resistive
heaters. Additionally, the substrate support member 208 may be in
electrical communication with a power supply configured to supply
an electrical bias to the substrate support member 200. The
sidewalls 205 of each of the respective chambers 200, 201
additionally include an aperture 209 formed therein, wherein the
aperture 209 is configured to communicate substrates into and out
of the respective chambers. As such, each of the apertures 209 may
generally be in selective communication with, for example, a
substrate transfer chamber, such as chamber 104 illustrated in FIG.
1. Therefore, in order to maintain a processing region within each
of processing chambers 200, 201, a valve 210, such as a gate or
slit valve, for example, may be positioned between each of the
apertures and the connecting chamber (as illustrated in FIG. 3), or
alternatively, a single valve may be implemented.
[0031] Additionally, each of the respective tandem chambers 200,
201 may include an upper and lower portions, wherein the upper
portion generally includes the processing regions 202, 203, and
wherein the lower portion generally includes a loading region 211.
The loading region 211 may generally be defined as the region
positioned below the electromagnets 218 (assuming electromagnets
218 are each a unitary rectangular magnet with a solid center),
which will be further discussed herein. In this configuration, the
substrate support members 208 may be lowered into the loading
region 211 below the lower surface of electromagnets 218. In this
position, a substrate may be positioned on the substrate support
member 208 via aperture and gate valve 210, which are formed into
the sidewalls of the chambers below the electromagnets 218. More
particularly, when the substrate support member 208 is lowered, the
lift pin assembly 212 may operate to lift a substrate off of the
upper surface of the substrate support member 208. Thereafter, a
robot blade may enter into the loading region 211 and engage the
substrate lifted by the lift pin assembly 212 for removal
therefrom. Similarly, with the substrate support member 208 in a
lowered positioned, substrates may be placed thereon for
processing. Thereafter, the substrate support member may be
vertically moved into a processing position, i.e., a position where
the upper surface of the substrate support member 208 is positioned
proximate the upper or top portion of the respective chamber.
[0032] In another embodiment of the invention, magnets 208 may be
rectangular in shape and have a hollow central portion. In this
configuration the substrate support member may be configured to
have an upper substrate support surface that corresponds with the
hollow central portion of the magnets 208, and similarly, the
aperture 209 and valve 210 may be located to correspond with the
hollow central portion of the magnet 208. Thus, in this
configuration the substrate support member may not need to be
movable in the vertical direction in order to load and unload
substrates. In yet another embodiment, the rectangular magnets 208
having a hollow central portion may again be used, however, the
aperture may again be positioned below the lower surface of the
magnet 208. As such, the substrate support member 208 may be
movable between a processing position (where the upper surface of
the substrate support member 208 is generally positioned proximate
the middle hollow portion of the magnet 208) and a loading position
(where the upper surface of the substrate support member 208 is
positioned below the lower surface of the lowest portion of the
magnet 218).
[0033] The upper portion of the respective chambers 200, 201
generally define the respective isolated processing regions 202,
203 for each of the respective chambers. Additionally, the upper
portions of the respective chambers provides the devices and/or
apparatuses necessary to support plasma generation. For example,
processing chamber 106 may generally include a unitary top or lid
member 215 that defines the upper boundary of the respective
processing regions 202, 203. The lid member 215 may optionally
include a gas distribution assembly 216, such as, for example, a
showerhead and blocker plate assembly configured to dispense a
processing gas into the respective processing regions 202, 203. The
shower head assembly, which may be manufactured from an
electrically conductive material, may be in electrical
communication with a power source (not shown) configured to supply
an electrical bias thereto, as is known in the art. Additionally,
the substrate support members 208 may be in electrical
communication with a power supply. Therefore, once a plasma is
generated in the respective processing regions, the power supply in
communication with the substrate support member may be used to
control bombardment of the ions in the plasma on the substrate
support member. The upper portions of the respective isolated
chambers may also include a circumferentially positioned pumping
channel 217, wherein pumping channel 217 is in fluid communication
with a common vacuum source (not shown), through, for example,
vacuum lines 237. Therefore, the respective pumping channels 217
are generally configured to maintain the respective chambers 200,
201, and more particularly, the respective processing regions 202,
203, at a pressure desired for semiconductor processing.
[0034] As briefly noted above, the upper portions of the respective
chambers 200, 201 also include a plurality of electromagnets 218A,
218B (generally referred to as electromagnets 218) positioned
around the perimeter of the respective processing regions 202, 203.
As illustrated in FIG. 2A, electromagnets 218 may be positioned
radially outward of the circumferential pumping channels 217, and
as such, electromagnets 218 may generally surround processing
regions 202, 203. Electromagnets 218, which may be in electrical
communication with a system controller 250 configured to control
the operation thereof, are generally positioned and configured to
generate a quasi-static magnetic field in the respective processing
regions 202, 203. The system controller, which may be a
micro-processor based controller, for example, may be configured to
electronically control both the electrical power applied to each of
the respective electromagnets 218, as well as various other system
parameters, such as gas flows, chamber pressures, and other
parameters generally controlled in a semiconductor processing
system. However, inasmuch as each of the electromagnets 218 are
individually and cooperatively controlled by system controller 250,
the cumulative magnetic field generated by the respective
electromagnets 218 may be modified and or controlled by the system
controller 250, for example, in accordance with a semiconductor
processing recipe. Furthermore, inasmuch as the present invention
implements a tandem etch processing chamber configuration, the
inwardly positioned electromagnets 218B may generate interfering
magnetic fields. Therefore, in order to prevent interfering fields
from entering into the adjacent processing chamber, a field
insulating shield 219, i.e., a shield manufactured from a material
configured to prevent the transmission of magnetic fields
therethrough, may be positioned between the respective chambers,
and more particularly, may be positioned between the respective
adjacent electromagnets 218B. Shield member 219 may, for example,
be manufactured from a number of dense metals known to shield
magnetic fields, such as, for example, steel, aluminum, and/or
iron. Additionally, shield member 219 may be manufactured from
various alloys, rubbers, and plastics, which may also have metal
dispersed therethrough to assist in the magnetic shielding
properties. Regardless of the actual composition, shield member
219, which may be of varying thicknesses, is generally manufactured
from one or more materials known in the art to shield magnetic
fields. As such, a magnetic field generated by the respective
electromagnets 218B will be directed towards the interior of the
respective processing chambers 200, 201, while the magnetic field
emanating in the opposite direction from the adjacent electromagnet
218B may be absorbed and/or canceled by the magnetic insulating
shield 219.
[0035] FIG. 3 illustrates a plan view of an exemplary tandem
processing chamber 106 of the invention. An example of the
positioning of the respective electromagnets 218 around the
respective chambers 200, 201 is illustrated in FIG. 3.
Additionally, the interstitially positioned magnetic shield member
219 is also illustrated. However, it is to be noted that
embodiments of the present invention are in no way limited to the
configuration of electromagnets 218 illustrated in FIG. 3. For
example, it is contemplated that each of electromagnets 218 may be
radial or arc shaped electromagnets configured to mirror a portion
of the perimeter of the respective processing regions 202, 203, as
illustrated in the exemplary configuration of FIG. 4. In this
configuration, a plurality of the arc shaped electromagnets 218 may
be positioned around the perimeter of the respective chambers to
form a generally circularly shaped electromagnet configured to
generate a magnetic field within each of the respective processing
regions surrounded by the arc shaped electromagnet. Additionally,
although the embodiments of the invention illustrated in FIGS. 2,
3, and 4 utilize four electromagnets surrounding each of the
respective chambers, the invention is in no way limited to using
any particular number of electromagnets. For example, the adjacent
magnets 218B positioned between the respective chambers 200, 201 in
FIG. 3 may be replaced by a unitary magnet 218B configured to
generate a magnetic field on one side for the first chamber 200 and
on another opposite side for a second chamber 201, as illustrated
in FIGS. 2B and 3A. In this embodiment, a unitary electromagnet
218B is positioned between the respective chambers and is
configured to supply a magnetic field to both chambers 200, 201
simultaneously. Additionally, as will be discussed herein, the
magnetic field output of unitary electromagnet 218B may be
controlled by a system controller so that a plasma generated in the
respective chambers 200, 201 may be stirred through cooperative
control of the magnetic field output of the respective
electromagnets 218A, 218B. Additionally, when the unitary
electromagnet 218B is utilized, the shield member 219 may be
removed from the central portion of the chamber where the
electromagnet 218B is positioned. However, the shield member may
still be positioned outward of the central electromagnet 218B so
that fields from the other electromagnets 218A may be prevented
from crossing over into the adjacent chamber. Further, although the
electromagnets are illustrated in a square-type configuration using
four magnets per chamber, embodiments of the invention contemplate
utilizing any number of magnets to surround the respective
chambers. For example, linear or straight magnets may be utilized
in an octagon type configuration, wherein eight magnets are
positioned around the perimeter of a chamber. Alternatively, the
arc shaped magnets noted above may be utilized to surround a
chamber, wherein any number of magnets from about 2 to about 24 or
more magnets may be used, as illustrated in FIG. 4. Regardless of
the shape or configuration of the electromagnets utilized,
embodiments of the invention contemplate that any number of
electromagnets may be used to surround a processing chamber, and
further, that the electromagnets may be configured in various
shapes and configurations that may surround a chamber.
[0036] Although the combination of the biased substrate support
members 208 and the electrically biased showerhead assemblies 216
may operate to generate a plasma within the respective processing
regions 202, 203, embodiments of the invention provide additional
assemblies for communicating a plasma into the respective
processing regions 202, 203. More particularly, as illustrated in
FIG. 2A, each of the respective chambers 200, 201 may include an
optional torroid assembly 220 configured to generate a plasma in
the respective processing regions. Each of the torroid assemblies
220 includes one or more hollow torroid conduits 221 that are in
fluid communication with a processing region on opposing sides
thereof. As illustrated in FIG. 2A, the torroid conduit 221
connects to a first side of a processing region 200 via a first
aperture 222. The torroid conduit 221 then extends over the top
portion 215 of the processing chamber 200 and returns to fluid
communication with the processing region 202 on the opposite side
thereof via a second aperture 222. The torroid conduit 221 may
generally be manufactured from an electrically conductive material,
and therefore, in order to reduce eddy currents generated therein
during plasma generation, an insulating member 225 may be
positioned inline with the torroidal conduit 221. The insulating
member 225 may generally operate to separate the conduit 221 into
two separate electrically isolated sections and prevent electrical
current from flowing therethrough. Inasmuch as a torroid conduit
221 is generally configured to generate a plasma and communicate
the plasma to a processing region, each torroid conduit 221 may
also include a gas supply conduit 223 and at least one electrically
biased coil 224 positioned proximate thereto. However, it is
understood that the gas supply conduit 223 may not be necessary for
proper plasma generation, as the gas supplied to the respective
processing regions 200, 201 may be communicated into the respective
torroids for plasma generation, which eliminates the need for the
additional gas supply 223. Each coil 224 may be wound around a
corresponding conduit 221 so that a field generated therefrom may
generally intersect and pass through the hollow interior portion of
the corresponding conduit 221. Each of the individual coils 224 may
be in electrical communication with a power supply 226, which may
be, for example, an RF power supply configured to drive the
respective coils 224. As such, the combination of the application
of electrical power to the respective coils 224 and the process gas
in the torroids causes a plasma to be generated within the torroid
conduit 221.
[0037] Additionally, although the apertures 222 of torroid conduit
221 are illustrated as entering into the respective processing
regions 202, 203 via the top or lid portion thereof (see FIG. 2A),
the present invention also contemplates that the torroid conduit
apertures may enter into the processing regions from the sidewall
205 of the chamber. As illustrated in FIG. 5, the respective
electromagnets 218 may be spaced apart slightly at their distil
ends, thus forming a region where the aperture 222 of the torroid
conduit 221 may communicate with processing regions 202, 203. As a
result of this configuration, the plasma generated within the
respective torroid conduits 221, which may number two or more, for
example, is communicated to the respective processing region and
distributed over the surface of the respective substrate positioned
therein for processing. Furthermore, although each of the
respective processing chambers are illustrated as including two of
the individual torroidal conduits 221, embodiments of the invention
are not limited to any specific number of torroidal conduits 221.
However, if two torroidal conduits are used, generally, the
conduits will extend above each of the respective processing
chambers and intersect or cross over each other at a generally
right angle. Although not required, this configuration generally
provides for an even distribution of the plasma generated within
the torroidal conduit 221 into the respective processing regions,
as placement of the torroidal conduits 221 at right angles to each
other provides for an aperture in the respective processing chamber
at 90 degree increments, and therefore, provides for a generally
uniform plasma to be distributed within the respective processing
region. However, embodiments of the invention contemplate that
three or more torroidal conduits may be utilized, and as such, the
corresponding number of plasma apertures may be positioned radially
around the respective processing regions in equal radial
spacing.
[0038] Furthermore, although embodiments of the invention
illustrated in FIG. 2A and FIG. 6 show both a showerhead assembly
and a torroidal plasma generation assembly, embodiments of the
invention contemplate that either one or both of the respective
plasma generation assemblies may be implemented in the tandem etch
chambers of the invention. More particularly, embodiments of the
invention generally contemplate that the showerhead assembly may be
omitted, while the torroidal plasma conduits may be implemented in
order to generate a plasma in the respective processing
regions.
[0039] In another embodiment of the invention, the tandem
processing chambers illustrated in FIG. 2A or FIG. 6 may be
implemented without the torroidal plasma conduits, as illustrated
in FIG. 8. As such, the tandem processing chamber implemented
without the torroidal plasma conduits may generally operate as a
tandem MERIE chamber. In this configuration a plasma may be
capacitatively generated through introduction of a processing gas
via the showerhead and the application of an electrical bias
between the showerhead and the substrate support member. The plasma
may be stirred and/or controlled via the selective actuation of a
plurality of electromagnets positioned around the respective
processing regions. The shield member positioned between the
adjacent tandem processing regions may operate to prevent cross
over of magnetic fields intended for one processing region into the
adjacent processing region. Therefore, in this tandem MERIE
configuration, two substrates may be simultaneously processed in
the tandem processing regions, thereby doubling the throughput
provided by conventional MERIE chambers, while not sacrificing the
control and uniformity provided by single MERIE chambers.
Alternatively, however, as noted above, the chamber may also be
configured to implement the torroidal plasma conduits and not the
showerhead assembly.
[0040] FIG. 6 illustrates an alternative configuration of the
processing system of the invention. More particularly, FIG. 6
illustrates an embodiment of the invention wherein the torroidal
conduits 221 are configured to enter into the respective processing
regions 202, 203 via the sidewall 205. Further still, the
embodiment of the invention illustrated in FIG. 6 utilizes a
central pumping aperture 230 centrally located within the bottom
portion of the respective chambers. The central pumping aperture
230, which may be in fluid communication with a vacuum pump 235,
generally operates to communicate a negative pressure to the
respective chambers 200, 201. As such, inasmuch as the respective
chambers are in fluid communication with each other as a result of
the central wall not extending completely to the bottom portion of
the respective chambers, a single pump in fluid communication with
the respective chambers via aperture 230 may be utilized to
maintain both of the respective chambers at a desired common
processing pressure. As a result of this configuration, processing
conditions in both chamber 200 and chamber 201 may be identical,
and therefore, variations between substrate processes within the
respective chambers may be minimized. It is to be noted, however,
that both the sidewall entrance configuration for the torroidal
conduits 221, as well as the central pumping configuration, may be
implemented individually or in combination into each of the
embodiments of the invention. Alternatively, the chambers 200, 201
may be separated/isolated from each other, i.e., aperture 230 may
be eliminated, and therefore, the pressure in the respective
chambers 200, 201 may be individually controlled. Aside from the
above noted distinctions, the exemplary tandem processing chamber
illustrated in FIG. 6 is similar to the tandem processing chamber
illustrated in FIG. 2A, and therefore, the structural description
of the chamber illustrated in FIG. 2A may be generally applied to
FIG. 6 for the common elements. As such, the chamber illustrated in
FIG. 6 again includes a system controller 650 configured to control
the electromagnets, plasma generation in the torroidal conduits,
gas flows into the chambers and conduits, pressures in the
respective chambers, electrical biases applied to generate plasmas,
and other parameters generally associated with a semiconductor
processing system.
[0041] FIG. 9 illustrates a tandem etch processing chamber 900
having cantilever-type substrate support members 908 positioned
therein. An exemplary cantilever mounted substrate support member
that may be used in the present invention may be found in U.S. Pat.
No. 6,001,267 entitled Plasma Enhanced Chemical Method, which is
hereby incorporated by reference. Chamber 900, which is
structurally similar to the tandem chamber illustrated in FIG. 6
(and therefore, the structural description of FIG. 6 may be applied
to the description of FIG. 9 where applicable), generally replaces
the centrally mounted stem-type substrate support members 208 with
the cantilevered substrate support members 908. With the exception
of the replacement of the substrate support members, the chamber
configuration and features may be similar to the exemplary chamber
illustrated in FIGS. 2 or 6. The cantilevered substrate support
members 908 utilized in the present exemplary embodiment generally
attach to the sidewall 905 of the respective chambers via one or
more support arms extending radially outward from the substrate
support member to a mounting plate on the outer wall 905. Inasmuch
as the cantilevered substrate support members 908 do not utilize a
bottom mounted stem portion to support the substrate platen, the
bottom portion of the respective chambers is generally open. As
such, the cantilevered substrate support members 908 allow for a
central pumping configuration, which may, for example, include a
shared central pumping aperture 930 in communication with a vacuum
pump 935. The use of the cantilevered substrate support member, and
in particular, the elimination of the stem portion of the
conventional substrate support members, may provide for improved
gas flow around the substrate support members 908. Additionally,
the cantilevered substrate support members 908 allow for the
individual processing chambers to both have central pumping
apertures formed therein, i.e., each chamber may have a central
pumping aperture formed therein immediately below each of the
respective cantilevered substrate support members 908. In this
configuration, each of the pumping apertures formed directly below
the cantilevered substrate support members 908 may be in fluid
communication with a common vacuum pump.
[0042] FIG. 10 illustrates an exemplary embodiment of a tandem etch
processing chamber 1000 having rotatable magnet assemblies 1001
positioned above the lid of the chamber 1000. The rotatable magnet
assembly is generally configured to generate a magnetic field in
the respective processing regions of the tandem chambers positioned
below. Generally, chamber 1000 is similar in construction to the
exemplary tandem etch chamber illustrated in FIG. 2A, and
therefore, the structural description of the chamber illustrated in
FIG. 2A may generally be applicable. However, the electromagnets
218 illustrated in FIG. 2A are removed from the perimeter of the
respective processing regions and replaced by the rotatable magnet
assemblies 1001 of the present exemplary embodiment. Additionally,
inasmuch as the rotatable magnet assemblies 1001 of the present
exemplary embodiment are positioned above the respective
chambers/processing regions 902 and not beside them, as with the
electromagnets 218 illustrated in FIG. 2A, the shield member 919
may generally extend above the top portion of the respective
chambers/processing regions 902 so that the magnetic fields
generated by the respective rotatable magnet assemblies 1001 do not
interfere with the magnetic fields in the adjacent processing
region. Shield member 919, therefore, may be configured to absorb,
cancel, or reflect the magnetic field lines passing therethrough so
that the field lines do not interfere with adjacent chambers. In
similar fashion to previous embodiments, the rotatable magnet
assemblies 1001 are generally configured to generate rotating or
movable magnetic fields in the processing regions of the chambers
positioned below the rotating magnets. The rotating or movable
magnetic fields may generally operate to stir and/or control a
plasma generated in the processing region therebelow. The
embodiment of FIG. 10 may also include a torroidal plasma source in
communication with each of the respective processing regions.
[0043] In operation, embodiments of the invention generally provide
a processing system configured to conduct etch processes on at
least two semiconductor substrates simultaneously. More
particularly, using the exemplary embodiment of the invention
illustrated in FIG. 1 as an example, substrates to be processed may
be placed into substrate processing system 100 via cassettes 109.
Then substrates, generally two, may be transported into loadlock
chamber 112 via robot 113, and loadlock chamber 112 may be sealed
from the chamber containing cassettes 109, through, for example, a
selectively actuated gate valve positioned between the respective
chambers. Thereafter, the loadlock chamber 112 may be brought to a
predetermined pressure and opened up to the substrate transfer
chamber 104. Once the two chambers are in communication with each
other, the two substrates in the loadlock chamber 112 may be
simultaneously transported into the substrate transfer chamber 104
via substrate transfer robot 105, which generally includes a robot
blade configured to simultaneously support two substrates. The two
substrates are generally supported in a side-by-side configuration
in the same horizontal plane by the robot blade. A pair of the gate
valves 210 positioned between the transfer chamber 104 and the
processing chamber 106 may be opened and the two substrates may be
inserted into a processing chamber 106, wherein an etch process may
be conducted thereon.
[0044] Once the robot blade is inserted into the processing chamber
106, the substrates may be simultaneously placed into the
respective tandem chambers 200, 201. The receiving process for the
respective tandem chambers 200, 201 generally includes, for
example, lowering of the respective substrate support members 208
into a loading position, i.e., a position where the substrate
support members 208 engage a lift pin assembly 212, and are
generally positioned below a plane through which the robot blade
may enter into the respective chambers via gate valve 210 and
entrance aperture 209. Thus, the robot blade may deposit the
substrates into the respective chambers 200, 201 by lowering the
substrates onto the lift pin assemblies 208. Once the substrates
are positioned on the lift pin assemblies 212, the robot blade may
be retracted from the respective chambers 200, 201 and the gate
valves 210 may be closed to seal the chambers 200, 201 from the
transfer chamber 104.
[0045] Once the loading process is complete, the respective
substrate support members 208 may be moved from a loading position
to a substrate processing position. The transition from the loading
position to the substrate processing position generally includes
raising the substrate support member vertically within the
respective chambers 200, 201, such that the distance from the upper
surface of the substrate support member 208 to the lower surface of
the showerhead assembly 216 is minimized. This movement of the
substrate support member 208 also operates to define the respective
processing regions 202, 203 within chambers 200, 201, as the upper
surface of the substrate support member 208 defines the lower
portion of the respective regions 202, 203. Additionally, the
vertical movement of the respective substrate support members 208
generally causes the lift pin assemblies 212 to lower the
substrates onto the upper surfaces of the respective substrate
support members 208 as the substrate support members 208 disengage
with the portion of lift pin assembly 212 positioned in the lower
portion of the respective chambers. Additionally, the process of
raising the substrate support members 208 to the upper position,
generally referred to as a processing position, also operates to
position the upper surface of the substrate support member on
approximately the same plane as the electromagnets 218 positioned
around the respective processing regions 202, 203. As such, the
magnetic fields generated by the respective electromagnets 218 will
generally be concentrated in the processing regions 202, 203
immediately above the substrate support members 208. Further, the
process of bringing the respective substrate support members 208
into the processing position may further include bringing the
respective chambers to a processing pressure, which generally
includes evacuating ambient gases from the respective chambers via
the aforementioned vacuum pump.
[0046] Once the respective substrates are loaded, moved into the
processing position, and the pressure in the respective chambers
200, 201 is brought to a desired processing pressure, a plasma may
be generated within both of the respective processing regions 202,
203. More particularly, a plasma may be generated via application
of a bias between substrate support member 208 and the showerhead
assembly 216, which then generates a plasma from a process gas
introduced into the respective processing region, or a plasma may
be generated within the torroidal conduits 221 and communicated to
the respective processing regions 202, 203 via apertures 222 at the
terminating ends of torroidal conduits 221. Additionally, if
desired, both the showerhead and torroidal conduits may be
cooperatively utilized to generate a plasma in the respective
processing regions.
[0047] In order to generate a plasma within the respective
torroidal conduits 221, a process gas must first be present
therein. Therefore, process gases from the respective processing
regions 202, 203 may be communicated into the respective torroidal
conduits 221, or alternatively, process gases may be delivered
directly into the respective torroidal conduits via a gas supply
223. Once the process gas is present within the respective
torroidal conduits 221, a field may be applied thereto in order to
ionize the process gas within the torroidal conduits 221 into a
plasma. The field required to ionize the process gases may be
generated by coils 224, which are in electrical communication with
power supply 226, which may be an RF power supply, for example. The
plasma generated within the torroidal conduits 221 generally
circulates through the torroidal path that extends through the
respective processing regions 202, 203 via apertures 222, and
therefore forms a continuous plasma path and extends over the
surface of the substrate.
[0048] Once the plasma is generated in the respective processing
regions, the density of a plasma may be manipulated and/or
controlled by the selective activation of the individual
electromagnets 218. More particularly, when each of the individual
electromagnets 218 are activated, the magnetic field generated by
the respective electromagnet 218 intersects the processing region
proximate thereto, as each of electromagnets 218 are positioned
proximate the perimeter of a processing region. Therefore, each of
the electromagnets 218 may be used to vary the magnetic field
intensity exerted on a particular portion of the processing region
positioned proximate thereto, which operates to confine or control
the plasma generated or communicated to that particular portion of
the processing region. For example, if a particular electromagnet
218 is supplied with an increased electrical power, the magnetic
field generated therefrom, which intersects the processing region
proximate thereto, will proportionally increase, and therefore, the
magnetic field density in the processing region proximate the
respective electromagnet 218 will correspondingly increase. As
such, through cooperative control of the individual electromagnets
218, the present invention provides for control over the magnetic
field in intensity through the entire processing region, which
inherently provides for control over the plasma density over the
entire processing region.
[0049] FIG. 7A illustrates a schematic representation of exemplary
tandem processing chambers 200, 201 of the invention during
processing, and more particularly, during the time period when
system controller 250 is operating to generate and control a
quasi-static, multi-directional magnetic field in each of the
respective processing regions 202, 203. Referring primarily to
FIGS. 2-5 and 7, opposing coil pairs 218 (coils positioned on
opposite sides of the respective processing regions 202, 203)
cooperatively operate to form mutually perpendicular magnetic field
vectors B.sub.y and B.sub.x, respectively, which are generally
parallel to the substrate support member and the surface of the
substrate positioned thereon. In order to generate and control the
mutually perpendicular magnetic field vectors, the magnitude and
direction of the current supplied to each of the individual
electromagnets may be controlled by system controller 250. The
perpendicular field vectors B.sub.y and B.sub.x generated by the
coil pairs may be defined by the following equations:
B.sub.x=B.multidot.cos(.theta.)
B.sub.y=B.multidot.sin(.theta.)
[0050] Therefore, given the desired or required values of the
magnetic field B, (which is the resultant vector illustrated in
FIG. 7), along with its angular orientation, (which is angle
.theta. in FIG. 7), system controller 250 may independently solve
the above noted equations to obtain associated magnetic field
vectors B.sub.y and B.sub.x, which provide the desired strength of
field and orientation. Thereafter, system controller 250 may
selectively regulate the application of electric currents to the
individual electromagnets, and in particular the electromagnet
pairs, to provide the desired magnetic field in the respective
processing chambers 200, 201. Additionally, the angular orientation
and magnitude of the generated magnetic fields may be independently
altered as quickly or as slowly as desired by changing the current
supplied to the electromagnets. The time that the field is on at
each angular position and the direction of angular stepping may be
varied, as well as the field intensity, since these parameters are
solely a function of changing the currents to the electromagnets
and are readily controlled by the system controller 250.
[0051] Therefore, as a result of the field control features
provided by system controller 250, the magnetic field in each of
the processing regions 202, 203 may be moved or stirred around the
respective processing region using selected orientation and time
increments, as illustrated by arrows A and B in FIG. 7. If desired,
the magnitude of the resultant field By may be changed as the
process or reactor configuration requires, or a constant field
strength may be used. In short, the electrical current-controlled
system provides the versatility of a fast or slow moving, constant
or varying strength magnetic field of constant or varied angular
velocity. In addition, the orientation of the field need not be
stepped or changed sequentially, but can be instantaneously
switched from any given orientation (or field strength) to another.
This versatility in independently controlling the direction and
magnitude of the magnetic field is distinct from existing
commercially useful rotating magnetic fields, which typically
rotate at a fixed relatively high frequency such as the standard
rate of 60 Hertz. In addition, the ability to "rotate" slowly, at a
rate, for example, as low as 2 to 5 sec./revolution (12 to 30
cycles/min.) or slower avoids problems, such as the eddy current
losses associated with the use of higher frequencies in metal
chambers. Furthermore, embodiments of the invention contemplate
that either DC or pulsed-type, RF for example, power supplies may
be used in conjunction with the controller and electromagnets of
the invention. In embodiments where opposing coil pairs are used,
for example, the magnetic field may be rotated in 90-degree
increments by successively and periodically connecting a DC power
supply to a first coil pair with positive polarity, then to a
second coil pair with positive polarity, then to the first coil
pair with negative polarity, and then to the second coil pair with
negative polarity. Alternatively, for example, the magnetic field
may be continuously rotated via the use of low frequency (in the
range of 0.1 to 10 Hz, for example) power supply having quadrature
outputs connected to provide current to the first coil pair offset
in phase by 90 degrees from the current provided to the second coil
pair 32.
[0052] FIG. 7B illustrates exemplary magnetic field lines for an
embodiment of the invention wherein four electromagnets 218A and
218B are positioned orthogonally around each of the processing
regions and a shield member 219 is positioned between the
electromagnets that share the common central wall. Shield member
219 and the common central wall are shown as a unitary member in
FIG. 7B, however, the invention is not limited to this
configuration, as the shield and wall members may be separate or
unitary. In order to improve the spatial uniformity over the
surface of a substrate being processed, adjacent sets of
electromagnets orthogonally positioned may be configured to augment
the strength of the magnetic field near the perimeter of the
substrate closest to the intersection of the adjacent
electromagnets (designated point Q in FIG. 7B) to reduce the rate
at which the magnetic field strength declines from a point on the
opposing side of the substrate (designated point P) to point Q. In
this configuration, the total magnetic flux produced by one
electromagnet pair (in this embodiment an electromagnet pair is
defined as two electromagnets positioned adjacent each other, i.e.,
two electromagnets that both terminate at one end at the same
corner) may be set to be sufficiently less than the total magnetic
flux produced by the adjacent electromagnet pair so that the
combined magnetic field from the two electromagnet pairs declines
in strength from point P to point Q across the surface of the
substrate. In other words, the use of adjacently positioned
opposing electromagnet pairs may operate to reduce the rate of
decline, but does not eliminate or reverse the decline, from point
P to point Q in the magnetic field strength. The ratio R (where
R>1) of the total magnetic flux produced by one electromagnet
pair to the total magnetic flux produced by the other electromagnet
pair may be adjusted to maximize the spatial uniformity of the ion
flux over the surface of the substrate being processed. Shield
member 219 operates to magnetically isolate the respective tandem
chambers from each other, and therefore, the magnetic field
generated by electromagnets for one processing region does not
cross over into the adjacent processing region and interfere with
the controllability of the field strength in that particular
processing region.
[0053] FIG. 7C illustrates a plan view of the magnetic field lines
generated by another embodiment of the invention. In this
embodiment, the respective tandem processing chambers 200 and 201
share a common central electromagnet 218B. As such, electromagnet
218B is configured to generate a magnetic field that may be
simultaneously used for processing in both tandem chamber 200 and
tandem chamber 201. Therefore, the system controller in electrical
communication with the respective electromagnets will generally be
configured to adjust the magnitude and direction of the field
generated by the central electromagnet 218B cooperatively with the
remaining electromagnets positioned around the remaining three
sides of the respective processing regions. For example, as
illustrated in FIG. 7C, the magnetic field generated by the central
electromagnet 218B and the lowermost electromagnets 218A is in a
clockwise direction, and therefore, assuming that a contributory
magnetic field effect is desired, the magnetic field cooperatively
generated by electromagnets 218C and 218D may be in a
counter-clockwise direction. This configuration may generate a
uniformly dense plasma area in a particular area of each of the
processing regions, and in the exemplary embodiment, the dense
plasma area would be in the area denoted by an "X" in FIG. 7C, as
the area proximate the "X" is where the respective field lines
converge. Similarly, the field direction of electromagnet 218B may
be switched to a counterclockwise direction, and therefore, the
associated magnetic fields generated by the remaining
electromagnets may also be switched in direction to maintain the
contributory field effect.
[0054] Furthermore, given that the system controller in each of the
above noted embodiments may selectively control the electrical
current supplied to each of the individual electromagnets, the
region of dense plasma generated by the electromagnets may be
selectively moved or stirred within the respective processing
regions. In short, the magnetic field control features of the
present invention provides the versatility of a fast or slow
moving, constant or varying strength magnetic field of constant or
varied angular velocity within each of the respective tandem
processing regions. In addition, the orientation of the field need
not be stepped or changed sequentially, as it may be
instantaneously switched from any given orientation (or field
strength) to another, i.e., the plasma confining magnetic field may
be switched from one quadrant in the processing region to another
quadrant in the processing region, where the respective quadrants
are not adjacent each other. Further still, inasmuch as embodiments
of the present invention are not limited to any particular number
of electromagnets or processing region/chamber shapes, the number
of sectors or regions may be varied in accordance with the number
of magnets and processing region chamber shape. Further, generally,
a sector defined within the processing region may correspond to an
area where the magnetic field generated therein is primarily
controlled by a single one of a plurality of electromagnets 218 or
pairs of electromagnets operating cooperatively.
[0055] FIGS. 11A-11D illustrate an exemplary plasma stirring
process that may be implemented by embodiments of the invention
through selective control of electromagnets positioned around
processing regions. In the exemplary embodiment, a tandem
magnetically enhanced etch chamber using a unitary central electro
magnet (designated electromagnet 1) and six surrounding
electromagnets (designated electromagnets 2-7) is used to
simultaneously stir a plasma in tandem processing regions. In FIG.
11A, which may be a first step of a plasma stirring process, the
magnetic field is configured to generate a dense plasma region in
the left side tandem processing region near the upper left hand
corner of the region, i.e., proximate the corners of magnets 2 and
6, while simultaneously generating a dense plasma in the right side
tandem region near the lower left corner of the processing region,
i.e., proximate the corners of magnets 1 and 5. In this
configuration the magnetic field between magnet 1 and magnet 2 is
set up to be in a clockwise direction, while the magnetic field
between magnets 4 and 6 is set up to be in a counterclockwise
direction, as shown by the arrows in FIG. 11A. Similarly, the
magnetic field between magnets 3 and 1 is set up to be in a
clockwise direction, while the magnetic field between magnets 7 and
5 is set up to be in a counterclockwise direction.
[0056] FIG. 11B illustrates an exemplary second step of a magnetic
field stirring process, wherein a dense plasma region is generated
in an upper right hand corner of the left hand side tandem
processing region, while a dense plasma region is generated in a
lower right hand corner of the right side tandem processing region.
In this configuration, for the left side tandem processing chamber,
the magnetic field between magnet 6 and magnet 2 is generally in a
counter clockwise rotation, while the magnetic field between magnet
1 and magnet 4 is in a clockwise rotation. Similarly, for the right
hand side tandem chamber, the magnetic field between electromagnets
3 and 7 is in a counterclockwise direction, while the magnetic
field between electromagnets 1 and 3 is in a clockwise
direction.
[0057] FIG. 11C illustrates an exemplary third step of a magnetic
field stirring process, wherein a dense plasma region is generated
in the lower right hand corner of the left side tandem processing
region, while a dense region is generated in an upper right hand
corner of the right side tandem processing region. In this
configuration, for the left side tandem processing region, the
magnetic field between electromagnet 2 and electromagnet 1 is in a
counterclockwise direction, while the magnetic field between
electromagnet 6 and electromagnet 4 is in a clockwise direction.
For the right side tandem processing region, the magnetic field
between electromagnet 1 and electromagnet 3 is generally in a
counterclockwise direction, while the magnetic field between
electromagnet 5 and electromagnet 7 is generally in a clockwise
direction.
[0058] FIG. 11D illustrates an exemplary fourth step of a magnetic
field stirring process, wherein a dense plasma region is generated
in a lower left hand corner of the left side tandem processing
region, while a dense plasma region is generated in an upper left
hand corner of a right side tandem processing region. In this
configuration, for the left side tandem processing region, the
magnetic field between electromagnet 2 and electromagnet 6 is in a
clockwise direction, while the magnetic field between electromagnet
1 and electromagnet 4 is in a counterclockwise direction. For the
right side tandem processing region, the magnetic field between
electromagnet 7 and electromagnet 3 is in a clockwise direction,
while the magnetic field between electromagnet 5 and electromagnet
1 is in a counterclockwise direction. Therefore, through the
sequential application of the magnetic fields illustrated in FIGS.
11A-11D, a dense plasma region in each of the respective processing
regions may be simultaneously circulated through each of the
respective processing regions. Additionally, although a circular
circulation has been illustrated in the exemplary embodiment, the
invention is not limited to this configuration. Rather, embodiments
of the invention contemplate that various plasma circulation
patterns may be implemented, including, for example, criss-cross
patterns, z-shaped patterns, and box patterns.
[0059] Once the individual processing recipe step is completed,
plasma generation may be terminated and the individual substrates
may be removed from the respective processing chambers 200, 201.
The unloading process generally includes lowering of the substrate
support member 208 from the processing position to the substrate
loading/unloading position. Once the substrate support member is in
the loading/unloading position, valves 210 may be opened in order
to allow a robot blade to access the respective processing chamber
and remove the processed substrates therefrom. Once the substrates
are removed, they may be transferred to another set of processing
chambers so that another processing recipe step may be conducted
thereon. Similarly, two additional substrates may be brought into
the processing chambers where the two substrates were just removed
therefrom so that a processing step may be conducted thereon. As
such, the exemplary configurations of the present invention, which
are generally illustrated in FIGS. 1, 2, and 6 allows for the
simultaneous processing of two substrates in the tandem processing
chambers.
[0060] While the foregoing is directed to embodiments of the
present invention, other and further embodiments of the invention
may be devised without departing from the basic scope thereof, and
the scope thereof is determined by the claims that follow.
* * * * *