U.S. patent application number 12/571677 was filed with the patent office on 2010-01-21 for method and system for supplying a cleaning gas into a process chamber.
This patent application is currently assigned to APPLIED MATERIALS, INC.. Invention is credited to Ganesh Balasubramanian, Dale DuBois, Karthik Janakiraman, Hichem M'Saad, Thomas Nowak, Juan Carlos Rocha-Alvarez, Ramprakash Sankarakrishnan, Visweswaren Sivaramakrishnan.
Application Number | 20100012273 12/571677 |
Document ID | / |
Family ID | 41429991 |
Filed Date | 2010-01-21 |
United States Patent
Application |
20100012273 |
Kind Code |
A1 |
Sankarakrishnan; Ramprakash ;
et al. |
January 21, 2010 |
Method and System for Supplying a Cleaning Gas Into a Process
Chamber
Abstract
A method and apparatus for cleaning a process chamber are
provided. In one embodiment, a process chamber is provided that
includes a remote plasma source and a process chamber having at
least two processing regions. Each processing region includes a
substrate support assembly disposed in the processing region, a gas
distribution system configured to provide gas into the processing
region above the substrate support assembly, and a gas passage
configured to provide gas into the processing region below the
substrate support assembly. A first gas conduit is configured to
flow a cleaning agent from the remote plasma source through the gas
distribution assembly in each processing region while a second gas
conduit is configured to divert a portion of the cleaning agent
from the first gas conduit to the gas passage of each processing
region.
Inventors: |
Sankarakrishnan; Ramprakash;
(Santa Clara, CA) ; DuBois; Dale; (Los Gatos,
CA) ; Balasubramanian; Ganesh; (Sunnyvale, CA)
; Janakiraman; Karthik; (San Jose, CA) ;
Rocha-Alvarez; Juan Carlos; (San Carlos, CA) ; Nowak;
Thomas; (Cupertino, CA) ; Sivaramakrishnan;
Visweswaren; (Cupertino, CA) ; M'Saad; Hichem;
(Sunnyvale, CA) |
Correspondence
Address: |
PATTERSON & SHERIDAN, LLP - - APPM/TX
3040 POST OAK BOULEVARD, SUITE 1500
HOUSTON
TX
77056
US
|
Assignee: |
APPLIED MATERIALS, INC.
Santa Clara
CA
|
Family ID: |
41429991 |
Appl. No.: |
12/571677 |
Filed: |
October 1, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12142402 |
Jun 19, 2008 |
|
|
|
12571677 |
|
|
|
|
Current U.S.
Class: |
156/345.29 ;
156/345.35 |
Current CPC
Class: |
F16K 31/06 20130101;
B08B 5/00 20130101; B08B 7/0021 20130101; Y10S 438/905 20130101;
C23C 16/4405 20130101; C23C 16/45561 20130101; F16K 1/221 20130101;
F16K 1/224 20130101; F16K 31/0655 20130101; F16K 31/088 20130101;
C23C 16/4409 20130101 |
Class at
Publication: |
156/345.29 ;
156/345.35 |
International
Class: |
C23F 1/08 20060101
C23F001/08 |
Claims
1. A process chamber comprising: a remote plasma source; a process
chamber having at least two processing regions, each processing
region comprising: a substrate support assembly disposed in the
processing region; a gas distribution system configured to provide
gas into the processing region above the substrate support
assembly; a gas passage configured to provide gas into the
processing region below the substrate support assembly; a first gas
conduit configured to flow a cleaning agent from the remote plasma
source through the gas distribution assembly in each processing
region; and a second gas conduit configured to divert a portion of
the cleaning agent from the first gas conduit to the gas passage of
each processing region.
2. The process chamber of claim 1 further comprising a valve
controlling flow between the first gas conduit and the second gas
conduit.
3. The process chamber of claim 2, wherein the valve comprises an
aluminum body.
4. The process chamber of claim 3, wherein the valve comprises: a
movable flapper having a flow-obstructing plate; at least one
magnet encased in the flapper; and a coupling mechanism operable to
rotate the flapper between a first position where the
flow-obstructing plate blocks flow through the body and a second
position where the flow-obstructing plate allows flow through the
body.
5. The process chamber of claim 4, wherein the coupling mechanism
is configured to rotate the flapper through magnetic
interaction.
6. The process chamber of claim 1 further comprising a source of at
least one of NF.sub.3, F.sub.2, SF.sub.6, Cl.sub.2, CF.sub.4,
C.sub.2F.sub.6, CCl.sub.4 or C.sub.2Cl.sub.6 coupled to the remote
plasma source.
7. A substrate processing system comprising: a loadlock chamber; a
transfer chamber coupled to the loadlock chamber; a remote plasma
source; and a process chamber coupled to the transfer chamber,
wherein the process chamber comprises: a chamber body having at
least a first processing region: a first substrate support assembly
disposed in the first processing region; a first gas distribution
assembly coupled to the remote plasma source and configured to
provide gases from the remote plasma source into first processing
region from above the substrate support assembly; and a first gas
passage coupled to the remote plasma source and configured to
provide gases from the remote plasma source into the first
processing region from below the substrate support assembly.
8. The substrate processing system of claim 7, wherein the chamber
body further comprises: a second processing region: a second
substrate support assembly disposed in the second processing
region; a second gas distribution assembly coupled to the remote
plasma source and configured to provide gases from the remote
plasma source into second processing region from above the
substrate support assembly; and a second gas passage coupled to the
remote plasma source and configured to provide gases from the
remote plasma source into the second processing region from below
the substrate support assembly.
9. The substrate processing system of claim 8 wherein the first and
second gas passages are oriented to produce a substantially inward
flow of gases into the interior volume.
10. The substrate processing system of claim 8 further comprising:
a valve having an inlet coupled to the remote plasma source and at
least one outlet coupled to the first and second gas passages,
wherein the valve comprises: a movable flapper having a
flow-obstructing plate; and a coupling mechanism operable to rotate
the flapper between a first position where the flow-obstructing
plate blocks flow through the valve and a second position where the
flow-obstructing plate allows gas to pass through the valve.
11. The substrate processing system of claim 10, wherein the
coupling mechanism is configured to rotate the flapper through
magnetic interaction.
12. The substrate processing system of claim 10, wherein the valve
flow contacting surfaces are comprised of a material compatible
with at least one of NF.sub.3, F.sub.2, SF.sub.6, Cl.sub.2,
CF.sub.4, C.sub.2F.sub.6, CCl.sub.4 or C.sub.2Cl.sub.6.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of co-pending
U.S. patent application Ser. No. 12/142,402, filed Jun. 19, 2008,
which application is herein incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] Embodiments of the invention generally relate to apparatuses
and methods for cleaning process chambers of substrate processing
apparatuses. More particularly, embodiments of the present
invention relate to apparatus and methods for cleaning a process
chamber used for deposition.
[0004] 2. Description of the Related Art
[0005] After a number of deposition steps have been performed in a
process chamber, the process chamber may need cleaning to remove
undesirable deposition residues that may have formed on the chamber
wall. One conventional approach for cleaning current chemical vapor
deposition (CVD) or plasma enhanced chemical vapor deposition
(PECVD) process chambers is to use cleaning plasma supplied from a
remote plasma source (RPS) separate from the process chamber. The
RPS provides the cleaning plasma, usually formed from a
fluorine-based cleaning gas, which is flowed into the deposition
chamber via gas circulation hardware comprising a gas box, gas
manifold, and a gas distribution system installed in the process
chamber.
[0006] To obtain a higher etching rate during cleaning, the
cleaning plasma is usually supplied in an active form comprised of
atomic fluorine radicals. However, complex transport paths from the
RPS to the deposition chamber usually results in a premature
recombination of the atomic fluorine radicals into molecular gases
that have a lower etching rate. Consequently, cleaning efficiency
may be low even if precursor dissociation efficiency of cleaning
gases is high. Further, for chambers having large volume and
intricate geometry, such as a 300 mm process chamber, the chamber
pumping port is usually close to a shower head utilized to deliver
cleaning gases to the chamber. Therefore, poor circulation of gases
under a substrate support assembly positioned between the
showerhead and pumping port results in decreased cleaning
efficiency under the substrate support assembly.
[0007] Therefore, there is a need for an improved apparatus and
method for cleaning a deposition chamber.
SUMMARY OF THE INVENTION
[0008] A method and apparatus for cleaning a process chamber are
provided. In one embodiment, a process chamber is provided that
includes a remote plasma source and a process chamber having at
least two processing regions. Each processing region includes a
substrate support assembly disposed in the processing region, a gas
distribution system configured to provide gas into the processing
region above the substrate support assembly, and a gas passage
configured to provide gas into the processing region below the
substrate support assembly. A first gas conduit is configured to
flow a cleaning agent from the remote plasma source through the gas
distribution assembly in each processing region while a second gas
conduit is configured to divert a portion of the cleaning agent
from the first gas conduit to the gas passage of each processing
region.
[0009] In another embodiment, a substrate processing system is
provided that includes a loadlock chamber, a transfer chamber
coupled to the loadlock chamber, a remote plasma source, and a
process chamber coupled to the transfer chamber. The process
chamber includes a chamber body having at least a first processing
region, a first substrate support assembly disposed in the first
processing region, a first gas distribution assembly coupled to the
remote plasma source and configured to provide gases from the
remote plasma source into first processing region from above the
substrate support assembly, and a gas passage coupled to the remote
plasma source and configured to provide gases from the remote
plasma source into the first processing region from below the
substrate support assembly.
[0010] In another embodiment, a method for supplying a processing
gas into a process chamber is disclosed. The method comprises
providing a plasma source, flowing a first volume cleaning agent
from the plasma source through the top of the process chamber into
an interior volume of the process chamber, and flowing a second
volume of cleaning agent into the interior volume from below a
substrate support assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] So that the manner in which the above recited features of
the present invention can be understood in detail, a more
particular description of the invention, briefly summarized above,
may be had by reference to embodiments, some of 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.
[0012] FIG. 1 is a schematic plan view showing one embodiment of a
processing system having a cleaning system.
[0013] FIG. 2 is a schematic cross-sectional view of one embodiment
of a twin process chamber.
[0014] FIG. 3A is a horizontal cross-sectional view illustrating
one embodiment of a valve used in the process chamber of FIG.
2.
[0015] FIG. 3B is a schematic partial isometric cut-away view
illustrating the valve of FIG. 3A.
[0016] FIG. 3C is a cross-sectional view illustrating the valve of
FIG. 3A.
[0017] FIG. 4 is a flowchart of method steps for one embodiment of
deposition sequence that may be performed in the process chamber of
FIG. 2.
[0018] FIG. 5 is an exploded cross-sectional view of another
embodiment of a flapper.
[0019] FIGS. 6-7 are partial sectional view and a top view of the
flapper of FIG. 5.
[0020] FIGS. 8A-8B are top and bottom views of another embodiment
of a valve body.
[0021] FIG. 8C is a cross-sectional view of the valve body taken
along section line 8C-8C of FIG. 8B.
[0022] FIG. 8D is a cross-sectional view of the valve body taken
along section line 8D-8D of FIG. 8C.
[0023] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures. It is contemplated that elements
disclosed in one embodiment may be beneficially utilized on other
embodiments without specific recitation.
DETAILED DESCRIPTION
[0024] Embodiments described herein relate to a substrate
processing system that is operable to perform a plasma process
(such as etch, CVD, PECVD and the like) on one or more substrates,
and undergo plasma cleaning to remove residues formed during the
deposition process. One illustrated example of the substrate
processing system comprises, without limitation, a factory
interface, a loadlock chamber, a transfer chamber, and at least one
process chamber having two or more processing regions that are
isolatable from each other and share a common gas supply and common
exhaust pump. To remove deposition residues from the interior of
the process chamber, a remote plasma source is operable to generate
cleaning plasma that is supplied into the interior of the process
chamber from the top and bottom of the process chamber. The
interior of the process chamber can thereby be cleaned in a more
efficient manner.
[0025] FIG. 1 is a schematic view showing an embodiment of a
substrate processing system 100. The substrate processing system
100 comprises a factory interface 110 where substrates are loaded
into and unloaded from at least one loadlock chamber 140, a
substrate transfer chamber 170 housing a robot 172 for handling
substrates, and at least one process chamber 200 connected to the
transfer chamber 170. The processing chamber 100 is adapted to
accommodate various plasma processes and support chamber hardware
such as etch, CVD or PECVD processes.
[0026] As shown in FIG. 1, the factory interface 110 may include
substrate cassettes 113 and a substrate-handling robot 115. Each of
the cassettes 113 contains substrates ready for processing. The
substrate-handling robot 115 may comprise a substrate mapping
system to index the substrates in each cassette 113 in preparation
for loading the substrates into the loadlock chambers 140.
[0027] The loadlock chambers 140 provide a vacuum interface between
the factory interface 110 and the transfer chamber 170. Each
loadlock chamber 140 may comprise an upper substrate support (not
shown) and a lower substrate support (not shown) stacked within the
loadlock chamber 140. The upper substrate support and the lower
substrate support are configured to support incoming and outgoing
substrates thereon. Substrates may be transferred between the
factory interface 110 and the loadlock chamber 140 via a slit valve
146, and between the loadlock chamber 140 and the transfer chamber
170 via a slit valve 148. The upper substrate support and lower
substrate support may comprise features for temperature control,
such as built-in heater or cooler to heat or cool substrates during
transferring.
[0028] The transfer chamber 170 includes a substrate-handling robot
172 operable to transfer substrates between the loadlock chamber
140 and the process chamber 200. More specifically, the
substrate-handling robot 172 may have dual substrate-handling
blades 174 suitable to transfer two substrates at the same time
from one chamber to another. The blades 174 may also be configured
to move independent each other. Substrates may be transferred
between the transfer chamber 170 and the process chamber 200 via
slit valves 176. The movement of the substrate-handling robot 172
may be controlled by a motor drive system (not shown), which may
include a servo or stepper motor.
[0029] FIG. 2 is a schematic cross-sectional view illustrating one
embodiment of the process chamber 200. The process chamber 200
comprises two processing regions 202 in which substrates 204 can
undergo plasma processing in a concurrent manner. Each processing
region 202 has sidewalls 212 and a bottom 214 that partially define
a process volume 216. The process volume 216 may be accessed
through an access port (not shown) formed in the walls 212 as
selectively sealed by valves 176 that facilitate movement of the
substrate 204 into and out of each processing region 202. The walls
212 and bottom 214 of each processing region 202 may be fabricated
from a unitary block of aluminum or other material compatible with
processing. The walls 212 of each processing region 202 support a
lid assembly 222, and also include the assembly of a liner 224
having an exhaust port 226 through which the processing region 202
may be evacuated uniformly by a vacuum pump (not shown).
[0030] A substrate support assembly 230 is centrally disposed
within each processing region 202. In one embodiment, the support
assembly 230 may be temperature controlled. The support assembly
230 comprises a support base 232 made of aluminum that may
encapsulate at least one embedded heater 234 operable to
controllably heat the support assembly 230 and the substrate 204
positioned thereon to a predetermined temperature. In one
embodiment, the support assembly 230 may operate to maintain the
substrate 204 at a temperature between about 150 degrees Celsius to
about 1000 degrees Celsius, depending on the processing parameters
for the material being processed.
[0031] Each support base 232 has an upper side 236 for supporting
the substrate 204, whereas the lower side of the support base 232
is coupled to a stem 238. The stem 238 couples the support assembly
230 to a lift system 240 that moves the support assembly 230
vertically between an elevated processing position and a lowered
position that facilitates substrate transfer to and from the
processing region 202. The stem 238 additionally provides a conduit
for electrical and thermocouple leads between the support assembly
230 and other components of the chamber 200. A bellows 242 may be
coupled between the stem 238 and the bottom 214 of each processing
region 202. The bellows 242 provides a vacuum seal between the
process volume 216 and the atmosphere outside each processing
region 202 while facilitating vertical movement of the support
assembly 230.
[0032] To facilitate the transfer of the substrate 204, each
support base 232 also has a plurality of openings 246 through which
lift pins 248 are movably mounted. The lift pins 248 are operable
to move between a first position and a second position. The first
position, shown in FIG. 2, allows the substrate 204 to rest on the
upper side 236 of the support base 232. The second position (not
shown) lifts the substrate 204 above the support base 232 so that
the substrate 204 can be transferred to the substrate-handling
robot 172 coming through an access port (not shown).
Upward/downward movements of the lift pins 248 may be driven by a
movable plate 250.
[0033] The lid assembly 222 provides an upper boundary to the
process volume 216 in each processing region 202. The lid assembly
222 may be removed or opened to service the processing regions 202.
In one embodiment, the lid assembly 222 may be fabricated from
aluminum.
[0034] The lid assembly 222 may include an entry port 260 through
which a processing gas may be introduced into the processing region
202. The processing gas may comprise deposition (or etch) gases
provided from a gas source 261, or cleaning plasma provided from a
remote plasma source (RSP) 262. A gas distribution assembly 270 may
be coupled to an interior side of the lid assembly 222. The gas
distribution assembly 270 includes an annular base plate 272 having
a blocker plate 274 disposed intermediate to a faceplate (or shower
head) 276. The blocker plate 274 provides an even gas distribution
to a backside of the faceplate 276. A processing gas supplied via
the entry port 260 enters a first hollow volume 278 partially
limited between the annular base plate 272 and the blocker plate
274, and then flows through a plurality of passages 280 formed in
the blocker plate 274 into a second volume 282 between the blocker
plate 274 and the faceplate 276. The processing gas then enters the
process volume 216 from the second volume 282 through a plurality
of passages 284 formed in the faceplate 276. The faceplate 276 is
isolated from the chamber walls 212 and blocker plate 274 (or base
plate 272) via an insulator material 286. The annular base plate
272, blocker plate 274 and faceplate 276 may be fabricated from
stainless steel, aluminum, anodized aluminum, nickel or other
compatible metal alloys cleanable with a plasma, such as a chlorine
based cleaning gas, a fluorine based cleaning gas, a combination
thereof or other selected cleaning chemistry.
[0035] To deliver the processing gas to each processing region 202,
a gas circulation system is installed between each processing
region 202 and the gas source 261 and RPS 262. The gas circulation
system comprises first gas conduits 290 that respectively link the
entry port 260 at the top of each processing region 202 to the gas
source 261 and RPS 262, and at least one second gas conduit 294
connected with the first gas conduit 290 via a valve 300. The
second gas conduit 294 is coupled to one or more passages 292 that
extends downward through the chamber walls and intersects one or
more cross-channels 296 that respectively open into a bottom
portion of each processing region 202. In the embodiment depicted
in FIG. 2, separate passages 292, 296 are utilized to couple each
region 202 separately to the valve 300. It is also contemplated
that each region 202 may have gas delivery thereto controlled by a
separate dedicated valve 300 so that the flow of cleaning gas may
be delivered selectively and independently to each region 202,
including delivering cleaning gas to one of the regions 202 and not
the other. When a cleaning plasma is provided from the RPS 262, the
valve 300 can be open so that a portion of the cleaning plasma that
is delivered through the top of each processing region 202 can also
be diverted to the bottom portion of each processing region 202.
The stagnation of cleaning plasma below the substrate support
assembly 230 can thereby be substantially prevented and the
cleaning efficiency to the region below the substrate support
assembly 230 be improved.
[0036] FIGS. 3A-3B are horizontal sectional and schematic partial
isometric views illustrating one embodiment of the valve 300. As
shown, the valve 300 comprises a valve body 330, a flapper 302, a
seal cup 304 and a coupling mechanism 308. The valve body 330 may
be fabricated from a high temperature material suitable for use
with the cleaning and process chemistries. Examples of suitable
materials include aluminum, aluminum oxide, aluminum nitride,
sapphire and ceramic, among others. Other examples of suitable
materials include materials that are resistant to corrosion from
fluorine and oxygen radicals. In one embodiment, the valve body 330
is fabricated from aluminum. The valve body 330 houses the flapper
302 which may be selectively rotated to substantially prevent flow
from passing between an inlet 399 of the valve body 330 and a pair
of outlet ports 332. The inlet 399 is configured to be coupled to
the RPS source 262, while the outlet ports 332 are configured to be
coupled to the region 202 through the second gas conduit 294 and
passages 292. The inlet 399 and outlet ports 332 may be configured
to accept a fitting suitable for making leak-free connection to the
conduits 290, 294.
[0037] The actuator portion of the flapper 302 is surrounded by the
cup seal 304, which is used to securely fix the seal cup 304 to the
valve body 330. The flapper 302 is divided into an outer body 310
having a generally cylindrical shape, and a flow-obstructing plate
312 attached to an opposite side of the outer body 310. In one
embodiment, the flapper 302 including the outer body 310 and
obstructing plate 312 may be a single undivided body made of
aluminum or other material as mentioned above. The flapper 302 and
body 330 are fabricated with close tolerances so that minimal
leakage occurs there between. Thus, the flapper 302 and body 330
are designed to eliminate the need for a separate dynamic seal
which may wear and/or be attached by the cleaning gases and/or
other species. When in use, the seal cup 304, which substantially
encapsulates the outer body 310, is adapted to allow relative
rotation of the flapper 302, and substantially seal the side of the
flow-obstructing plate 312 corresponding to the interior of the gas
circulation system from the outside environment.
[0038] The rotation of the flapper 302 is driven via the coupling
mechanism 308. In one embodiment, the coupling mechanism 308 has a
generally U-shape with two magnetized end portions 318. The
magnetized end portions 318 have embedded magnets that are
completely enclosed inside the flapper 302 so that direct contact
of the embedded magnet to corrosive gases is prevented. The
coupling mechanism 308 is placed over the seal cup 304, with the
two magnetized end portions 318 respectively facing two opposite
poles 320 of a magnet 322 embedded in the outer body 310. The
magnet 322 may be a permanent magnet and/or an electromagnet. As a
gap is present between the seal cup 304 and the coupling mechanism
308, the seal cup 304 is protected from high temperature contact
with the coupling mechanism 308. When the coupling mechanism 308
rotates, the magnetic attraction between the magnetized end
portions 318 and the opposite poles 320 of the magnet 322 causes
the flapper 302 to rotate. In this manner, the orientation of the
flow-obstructing plate 312 can be changed by rotation to either
allow gas flow passage (open state, as shown in FIG. 3A) or block
gas flow passage (closed state, as shown in phantom in FIG.
3A).
[0039] FIG. 3C is a cross-sectional view showing one embodiment of
the valve 300 coupled to the second conduit 294 taken along section
line C-C of FIG. 3A. The cup seal 304 includes a collar 306 which
may be fastened to the valve body 330 to retain the flapper 302. A
static seal 314 may be provided between the valve body 330 and
collar 306 to prevent leakage. The static seal 314 may be
fabricated from a material suitable for use with the process and
cleaning chemistries, which in embodiment utilizing fluorine-based
cleaning gases, may be VITON. Since the valve 300 has no moving,
shaft or dynamic seals, the service life of the valve is greatly
extended over conventional designs, and can be operated at
temperatures above 250 degrees Celsius with substantially no
corrosion of the valve components.
[0040] The rotation of the flapper 302 may be facilitated via a
ball bearing 334 that interfaces between an end of the
flow-obstructing plate 312 and a wall 335 of the valve body 330,
and ball bearing 336 that interfaces between the outer body 310 to
the seal cup 304. Driven via the coupling mechanism 308, the
orientation of the flow-obstructing plate 312 can thereby be
oriented to either block or permit the passage of an incident gas
flow 340, such as the cleaning gas being directed into the second
gas conduit 294.
[0041] Alternatively, or in addition to the ball bearings 334, 336,
a bearing 398 may be disposed between the flapper 302 and the valve
body 330 as shown in FIG. 3D. The bearing 398 may be fabricated
materials that are resistant to corrosion from fluorine and oxygen
radicals, which in one embodiment is a ceramic material. The
bearing 398 includes an upper race 395 that rotates on a lower race
397 via a plurality of roller 396. The upper race 395 is in contact
with the flapper 302. In one embodiment, the upper race 395 is
press-fit to the flapper 302. The lower race 397 is in contact with
the valve body 330. In one embodiment, the lower race 397 is
press-fit to the valve body 330. The rollers 396 may have a
cylinder, ball, tapered, conical or other suitable shape.
[0042] Alternatively, one or more magnetic bearings 390 may be
utilized to provide a bearing between the flapper 302 and the valve
body 330 as shown in FIG. 3E. The magnetic bearing 390 includes a
pair of repelling magnets. In the embodiment depicted in FIG. 3E,
the magnetic bearing 390 includes two pair of repelling magnets, a
first pair 392A, 394A and a second pair 392B, 394B disposed at
opposite ends of the flapper 302. The magnets 394A, 394B are
encapsulated with in the flapper 302 so that they are protected
from the fluorine and oxygen radicals present in the cleaning
gases. The magnets 392A, 392B may be permanent magnets or
electromagnets. The magnets pair 392A, 394A and 392B, 394B function
to levitate the flapper 302 within the valve body 330 so that the
flapper 302 may be freely rotated by the magnetic interaction with
the coupling mechanism 308.
[0043] The coupling mechanism 308 rotated by an actuator 390 to
open and close the valve 300. The actuator 390 may be a solenoid,
air motor, electric motor, pneumatic cylinder or other actuator
suitable for controlling the rotary motion of the coupling
mechanism 308. The actuator 390 may be mounted to the valve 300,
process chamber 200 or other suitable structure.
[0044] FIG. 4 is a flowchart illustrating method steps of one
embodiment of a sequence for operating the process chamber 200. In
initial step 402, a substrate is introduced in a processing region
202 of the process chamber 200 to undergo a plasma process, such as
an etch or deposition process. In step 404, while the valve 300 is
closed, a process gas is delivered from the gas source 261 into the
process volume 216 through the first conduit 290 and the gas
distribution plate assembly 270 at the top of each processing
region 202. In step 406, after the plasma process is completed, the
substrate is removed out of the processing region 202. In step 408,
while the valve 300 is in a closed state, a cleaning agent from the
RPS 262, such as a chlorine based cleaning gas, a fluorine based
cleaning gas, or a combination thereof, is delivered through the
first conduit 290 and the gas distribution plate assembly 270 at
the top of each processing region 202. In one embodiment, the
cleaning gas may comprise at least one of NF.sub.3, F.sub.2,
SF.sub.6, Cl.sub.2, CF.sub.4, C.sub.2F.sub.6, CCl.sub.4 or
C.sub.2Cl.sub.6. While the cleaning gas is introduced through the
top of each processing region 202, the valve 300 in step 410 is
opened for a period of time to divert a portion of the supplied
cleaning plasma through the passages 292 to the bottom 214 of each
processing region 202 below the substrate support assembly 230.
This additional flow of cleaning plasma reduces the recombination
of fluorine radicals, and eliminates the flow stagnation under the
support assembly 230. Moreover, the introduction of the diverted
cleaning gas through the channels 196 creates a well-mixed
turbulent flow below the substrate support assembly 230 prior to
being pumped out of the chamber 200. As a result, the cleaning rate
in each processing region 202 may be improved. It is contemplated
that the opening of the valve 300 in step 410 may occur prior to or
simultaneously with the introduction of the cleaning gas at step
408. In step 412, once the cleaning operation is completed, the
supply of cleaning gas is terminated. It is also contemplated that
the valve 300 may be another type of valve suitable for controlling
the relative flows through the conduits 290, 294 from the RPS
source 262, including switching between the flows through the
conduits 290, 294 between flow and no-flow conditions, or providing
a range of selected flow ratios through the conduits 290, 294.
[0045] As has been described above, the substrate processing system
is thus able to controllably flow processing gases through both the
top and bottom of a process chamber. During cleaning, the
controlled supply of a cleaning plasma concurrently through the top
and bottom of the process chamber into the process volume (i.e.,
from both the top and bottom sides of the substrate support) can
decrease the recombination of chemical radicals inside the process
volume. The horizontal introduction of the cleaning gas below the
support assembly produces a turbulent flow which enhances chamber
cleaning. Further, lower total mass flow rate causes a higher
weight percentage of cleaning agents to flow into the bottom of the
processing chamber. For example, 42.67 mass percentage of cleaning
agent may be directed to the bottom of the processing chamber
through the conduit 294 and passages 292 under a total plasma flow
rate at 5000 sccm while only 28.8 mass percentage of cleaning agent
flows to the bottom of the processing chamber under a total plasma
flow rate at 15,000 sccm. As a result, lower total plasma flow rate
can divert more percentage of the cleaning agent to the bottom of
the process chamber, and thus the process chamber can be cleaned
more efficiently.
[0046] FIG. 5 is an exploded view of another embodiment of a
flapper 500. FIG. 6 is a top view of the flapper 500. Referring to
both FIGS. 5-6, the flapper 500 includes a body 502, a cap 504 and
one or more magnets 506. flapper 302 including the outer body 310
and obstructing plate 312 may be a single undivided body made of
aluminum or other material as mentioned above. The body 502 and cap
504 may be fabricated from the materials described above.
[0047] The body 502 includes outer body 534 and an obstructing
plate 538. The outer body 534 has recess 528 formed in a first end
530 that is sized to receive at least a portion of the cap 504. In
one embodiment, the cap 504 is pressed fit into the recess 528 so
the cap 504 cannot rotate within the recess 528. Alternatively, the
cap 504 may be pinned, adhered, bonded, welded or otherwise
fastened to the body 502 in a manner that prevents rotation.
[0048] The obstructing plate 538 extends from a second end 540 of
the body 502 to a disk 536. The disk 536 is sized to interface with
a recess formed in the valve body to facilitate rotation of the
flapper 500. The disk 536 generally has a diameter less than a
diameter of the outer body 534. A bottom surface 532 of the disk
536 includes pocket 520 for retaining a ball bearing (not shown)
that facilitates rotation of the flapper 500.
[0049] The second end 540 of the body 502 also includes a plurality
of depressions 542 formed therein. In one embodiment, the
depressions 542 are radially orientated and equally spaced about a
polar array. The depressions 542 are configured to mate with
projections (not shown) extending from upper race 395 so that the
race 395 is locked in rotation with the flapper 500.
[0050] FIG. 7 is a partial sectional view of the disk 536 through
the pocket 520. The pocket 520 includes a blind hole 606 that is
formed concentric to the centerline of the body 502. A countersink
604 is formed concentric with the hole 606. The countersink 604 is
formed at an angle that facilitates retention of the ball bearing
within the pocket 520.
[0051] Returning to FIGS. 5-6, the cap 504 includes a cylindrical
body 510 having an upper end 516 and a lower end 518. The
cylindrical body 510 has a diameter that fits within the recess 528
of the body 502. A lip 508 formed at the upper end 516 of the body
510 so that the end 530 of the body 502 seats on a ledge 512
defined by the lip 508, thereby setting the penetration of the body
510 into the body 502 at a predetermined depth. A pocket 520 may
also be formed in the cap 504 to facilitate retention of a ball
bearing (not shown) on the center axis of the flapper 500.
[0052] A cross-hole 514 is formed through the body 510 to receive
the one or more magnets 506. The cross-hole 514 is formed
perpendicular to a centerline of the flapper 500. The one or more
magnets 506 are captured in the cross-hole 514 when the cap 504 is
inserted into the recess 528 of the body 502.
[0053] In one embodiment, the one or more magnets 506 include a
plurality of magnets stacked in a linear arrangement. In the
embodiment of FIG. 5, the one or more magnets 506 include a North
pole 524, a South pole 522 and one more magnets 526 stacked
therebetween.
[0054] FIGS. 8A-8B are top and bottom views of another embodiment
of a valve body 800. The valve body 800 is generally a unitary
aluminum or ceramic member, although the valve body 800 may be
fabricated from other suitable materials. The valve body 800
includes a top surface 802 and a bottom surface 804. A first bore
810 is formed into the body 800 from the top surface 802. The first
bore 810 is positioned at least partially in an extending portion
806. The extending portion 806 has a first passage 812 (shown in
phantom) formed therethrough. The end of the first passage 812
servers to connect the valve body 800 to the conduits leading to
the remote plasma source 262. The second end of the first passage
812 is teed into a second passage 824 (also shown in phantom). The
first bore 810 is aligned with the first passage 812 and is sized
to receive the flapper as to control the flow of fluid through the
first passage 812 to the second passage 824. A plurality of
threaded blind mounting holes 816 are formed in the first side 802
of the valve body 800 to retain the seal cup (not shown) to the
valve body 800.
[0055] The second side 804 of the valve body 800 includes a second
and third bores 818. The second and third bores 818 communicate
with the second passage 824 on either side of intersection of the
first and second passages 812, 824. An o-ring groove 820
circumscribes each bore 818 to allow the conduits extending from
the valve 800 into the chamber body to be sealingly coupled to the
valve 800. The o-rings may be compressed to seal a fitting coupled
to the second and third bores 818 using fasteners (not shown)
passed through mounting holes 822 formed through the body 800. In
the embodiment depicted in FIGS. 8A-8B, four mounting holes 822 are
associated with each bore 818.
[0056] Referring now to the sectional view of FIG. 8C, the second
passage 824 may be sealed at either end by plugs 830. The plugs 830
may be pressed fit, welded, bonded, adhered, threaded or sealingly
coupled to the body 800 by another suitable manner.
[0057] Referring now to the sectional view of FIG. 8D, the first
bore 810 include a ledge 832 that interfaces with the outer body of
the flapper and/or supports the lower race 397 of the bearing 398.
The obstructing plate of the flapper extends into the bore 810 and
may be rotated as to control the flow through the first passage
812. The bottom of the first bore 810 may also include a pocket 520
to facilitate retention of the ball (not shown) disposed between
the flapper and the body 800. In embodiments wherein a bearing 398
is utilized, the ledge 832 may include a plurality of depressions
840 that are configured to mate with projections extending from the
lower race 397 of the bearing 398 such that the lower race 397 is
fixed to the body 800 while the flapper 500 rotates.
[0058] Returning to FIG. 1, a flange support 299 is coupled in line
with the outlet of the remote plasma source 262 to allow a pressure
sensor 297 to detect a metric indicative of the output pressure of
the remote plasma source 262. The sensor 297 may be in the form of
a manometer, pressure gage or other sensor suitable for obtaining a
metric indicative of the pressure of the cleaning agent exiting the
remote plasma source 262.
[0059] FIG. 9 depicts one embodiment of flange support 299. The
flange support 299 includes an inlet 902 and two outlets 904, 906.
The inlet 902 is coupled to the outlet of the remote plasma source
262 and fluidly coupled to the first outlet 904 through a main
passage 920 extending through the flange support 299. The first
outlet 904 is coupled to the conduit that provides the cleaning
agent from the remote plasma source 262 to the valve 300 and entry
ports 260. The second outlet 906 is fluidly coupled to the main
passage 920 coupling the inlet 902 to the first outlet 904 by a
secondary passage 922. The second outlet 906 is configured to
accept the sensor 297.
[0060] In one embodiment, the flange support 299 includes a flange
base 912, a pipe 914, an elbow 916 and a flange 918 which are
assembled as a pressure tight assembly. In one embodiment, the
flange base 912, pipe 914, elbow 916 and flange 918 are fabricated
from aluminum or stainless steel and are welded together, for
example, by a continuous weld. The flange base 912 includes a
cylindrical body 926 through which the main passage 920 is formed.
The cylindrical body 926 has a major flange 928 at a first end and
a minor flange 930 through a second end.
[0061] The inlet 902 is formed through the minor flange 930 and is
circumscribed by an o-ring groove 932 on its face 934. The face 934
of the minor flange 930 also includes a plurality of mounting
holes, not shown, which is one embodiment are in the form of a
plurality of through holes.
[0062] The first outlet 904 is formed through the major flange 928.
A face 936 of the major flange 928 is finished to provide a sealing
surface. The face 936 of the major flange 928 also includes a
plurality of mounting holes, not shown, which is one embodiment are
in the form of a plurality of through holes.
[0063] The cylindrical body 926 includes a hole 938 which breaks
into the main passage 920. In one embodiment the hole 938 is formed
substantially perpendicular to the centerline of the body 926,
which is coaxial with the centerline of the main passage 920.
[0064] The pipe 914 is configured to sealing couple to the
cylindrical body 926 in a manner that fluidly coupled a passage 940
defined through the pipe 914 with the hole 938. In one embodiment,
a first end of the pipe 914 has a taper or has a reduced outside
diameter that is inserted into the hole 938 to facilitate coupling
of the pipe 914 to the body 926. The second end of the pipe 914 may
have a taper or has a reduced outside diameter that is inserted
into the elbow 916 to facilitate coupling of the pipe 914 to the
elbow 916.
[0065] The flange 918 includes a cylindrical stem 950 having a
passage 960 formed therethrough. One end of the stem 950 has a lip
952. The lip 952 circumscribes a port 954 that defines the second
outlet 906. The port 954 is configured in manner suitable for
coupling the sensor 297 to the flange support 299.
[0066] In one embodiment, a face 956 of the lip 952 includes a
recess 958 which is concentric with the passage 960 through the
stem 950. The face 956 of the lip 952 may have an orientation
substantially perpendicular to the centerline of the passage 960. A
backside 962 of the lip 952 may be tapered to facilitate coupling a
fitting, not show, utilized to secure the sensor 297. In one
embodiment, the backside of the lip forms an angle with the stem of
about 205 degrees. The passage 960 formed through the flange 918, a
passage 964 formed through the elbow 916, the passage 940 formed
through the pipe 914 and the hole 938 formed in the support flange
912 define the secondary passage 922.
[0067] Thus, the flange support 299 allows direct delivery of the
cleaning agents from the remote plasma source 262 with minimal
obstruction which would adversely promote recombination.
Additionally, the flange support 299 facilitates coupling of the
sensor 297 in a convenient location that is remote from the other
utilities routed to the top of the chamber.
[0068] While the foregoing is directed to certain 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.
* * * * *