U.S. patent application number 11/438056 was filed with the patent office on 2006-09-21 for heated gas line body feedthrough for vapor and gas delivery systems and methods of employing same.
Invention is credited to Raynald B. Cantin, Craig M. Carpenter.
Application Number | 20060207506 11/438056 |
Document ID | / |
Family ID | 25463073 |
Filed Date | 2006-09-21 |
United States Patent
Application |
20060207506 |
Kind Code |
A1 |
Carpenter; Craig M. ; et
al. |
September 21, 2006 |
Heated gas line body feedthrough for vapor and gas delivery systems
and methods of employing same
Abstract
A feedthrough device for use in deposition chambers such as
chemical vapor deposition chambers and atomic layer deposition
chambers and methods using the same in association with such
chambers as well as chambers so equipped. The feedthrough device
includes an associated heating device to maintain the temperature
of the feedthrough device above a predetermined level and thus
maintain a temperature differential between the deposition chamber
body and a vaporize organometallic precursor as it passes
therethrough. The feedthrough device may include a helical groove
formed along the surface of a longitudinal body portion thereof to
complementarily receive a resistance type cable heater. The heater
may further include a temperature sensing device to assist in
monitoring and controlling the temperature of the feedthrough
device.
Inventors: |
Carpenter; Craig M.; (Boise,
ID) ; Cantin; Raynald B.; (Boise, ID) |
Correspondence
Address: |
TRASK BRITT
P.O. BOX 2550
SALT LAKE CITY
UT
84110
US
|
Family ID: |
25463073 |
Appl. No.: |
11/438056 |
Filed: |
May 18, 2006 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
09932860 |
Aug 17, 2001 |
|
|
|
11438056 |
May 18, 2006 |
|
|
|
Current U.S.
Class: |
118/715 ;
427/248.1 |
Current CPC
Class: |
C23C 16/455
20130101 |
Class at
Publication: |
118/715 ;
427/248.1 |
International
Class: |
C23C 16/00 20060101
C23C016/00 |
Claims
1. A feedthrough device for conveying liquid through a chamber body
of a deposition chamber, the feedthrough device comprising: a
longitudinal body having a first end and a second end; a lumen
defined to extend through the longitudinal body from the first end
to the second end; and a heating device associated with the
longitudinal body configured for heating the feedthrough device,
wherein the feedthrough device is configured to be complementarily
received in an internal portion of the chamber body.
2. The feedthrough device of claim 1, wherein the heating device
includes a resistance heater.
3. The feedthrough device of claim 2, further comprising a helical
groove formed on an exterior surface of the longitudinal body and
wherein at least a portion of the resistance heater is disposed
within the helical groove.
4. The feedthrough device of claim 3, wherein the resistance heater
includes a conductive sheath and wherein the helical groove is
configured to complementarily receive at least a portion of the
conductive sheath.
5. The feedthrough device of claim 4, wherein at least a portion of
the conductive sheathing is adhered to the longitudinal body.
6. The feedthrough device of claim 4, wherein at least a portion of
the conductive sheathing is welded to the longitudinal body.
7. The feedthrough device of claim 4, wherein the conductive sheath
is formed of stainless steel.
8. The feedthrough device of claim 1, further comprising a
temperature sensing device associated with the heating device and
longitudinal body.
9. The feedthrough device of claim 8, wherein the temperature
sensing device includes a thermocouple.
10. The feedthrough device of claim 8, wherein the temperature
sensing device is positioned within a conductive sheath.
11. The feedthrough device of claim 1, further comprising a
shoulder portion adjacent the first end of the longitudinal body,
wherein the longitudinal body exhibits a first diameter and the
shoulder portion exhibits a second larger diameter.
12. The feedthrough device of claim 11, further comprising at least
one channel formed in a surface of the shoulder portion, the at
least one channel being configured to at least partially receive a
sealing member therein.
13. The feedthrough device of claim 11, further including a
coupling portion adjacent the second end of the longitudinal body,
the coupling portion being configured to be sealingly coupled to a
portion of plumbing associated with a vapor source.
14. The feedthrough device of claim 13, wherein the coupling
portion includes a set of threads.
15. The feedthrough device of claim 13, wherein at least the
longitudinal body comprises stainless steel.
16. The feedthrough device of claim 13, wherein at least the
longitudinal body comprises aluminum.
17. A method of converting a chemical vapor deposition chamber
having a chamber body, a chamber lid and a first feedthrough device
positioned in an interior portion of the chamber body into an
atomic layer deposition chamber, the method comprising: removing
the first feedthrough device from the chamber body; and inserting a
second feedthrough device and an associated heating device into the
interior portion of the chamber body.
18. The method according to claim 17, further comprising
configuring the associated heating device to helically surround at
least a portion of the second feedthrough device.
19. The method of according to claim 18, further comprising forming
a helical groove in the second feedthrough device to
complementarily receive at least a portion of the associated
heating device.
20. A method of converting a chemical vapor deposition chamber
having a chamber body, chamber lid and a feedthrough device
positioned in an interior portion of the chamber body into an
atomic layer deposition chamber, the method comprising: removing
the feedthrough device; fitting the feedthrough device with a
heater device; disposing the feedthrough device and heater device
into the interior portion of the chamber body.
21. The method according to claim 20, wherein fitting the
feedthrough device with a heater device includes forming a helical
groove in an exterior surface of the feedthrough device and
complementarily positioning at least a portion of the heater device
into the helical groove.
22. A method of delivering vapor to a vapor delivery head in a
deposition chamber, the method comprising: providing a source of
vapor; defining a vapor delivery path between the source of vapor
and the vapor delivery head including: providing a first section of
plumbing from the source of vapor to a chamber body of the
deposition chamber; providing a feedthrough device in an interior
portion of the chamber body; coupling the feedthrough device to the
first section of plumbing; providing a second section of plumbing
from the feedthrough device to the vapor delivery head; and
coupling the second section of plumbing to the feedthrough device;
heating the first section of plumbing; and heating the feedthrough
device.
23. The method according to claim 22, wherein heating the
feedthrough device includes providing a resistance heater and
helically positioning a portion of the resistance heater about a
length of the feedthrough device.
24. The method according to claim 23, further comprising forming a
helical groove along an exterior surface of the feedthrough device
and positioning at least a portion of the resistance heater in the
helical groove.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of application Ser. No.
09/932,860, filed Aug. 17, 2001, pending.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to vapor and gas
delivery systems and more particularly to the heating of a gas line
body feedthrough used in a vapor delivery system such as a chemical
vapor deposition chamber or an atomic layer deposition chamber.
[0004] 2. State of the Art
[0005] Modern semiconductor processing equipment, specifically
chemical vapor deposition (CVD) and atomic layer deposition (ALD)
systems, are migrating to the use of organometallic precursors such
as tantalum tetraethoxide dimethylamino ethoxide (TAT-DMAE) as well
as halogen-metallic chemistries such as TiCl.sub.4 and others for
metal, metal-oxide and metal-nitride film depositions (collectively
referred to herein as organometallic precursors). Conventional
precursors have typically been delivered in a gas or vapor state
thus making them amenable for use in the vapor deposition process,
including ease of maintaining the precursors in the vapor state, as
they are delivered to the chamber from the vapor source. However,
organometallic precursors are typically delivered for use as a
liquid and sometimes as a solid. Many of such precursors have low
vapor pressures and others exhibit moderate vapor pressures. The
organometallic sources are typically vaporized and transported
through the delivery plumbing to the process chamber. Conventional
methods of vaporization include the use of bubbler ampoules or
direct liquid injection systems, which comprise a chemical ampoule,
a liquid flow meter, a heated injector, a carrier gas mass flow
controller (MFC) and heated vapor delivery lines between the
precursor source and the chamber.
[0006] Referring to FIG. 1, a conventional CVD chamber 100 is
shown. The chamber 100 includes a body 102 and a lid 104 which are
configured to allow removal of the lid 104 from the body 102. The
removable lid 104 provides for access to and maintenance of the
chamber interior including the chamber cavity 106. A vapor delivery
path 107 is conventionally defined to pass through the chamber body
102 using a feedthrough device 108 which connects to the heated
vapor plumbing (conduit) 110 at the lower side of the chamber at
one end 112 thereof and mates to the lid 104 at the opposite end
114. The vapor delivery path 107 may continue through additional
vapor plumbing (conduit) 116 before it travels through the lid 104
and is discharged into the chamber cavity 106 through a vapor
delivery head 118, also termed a "showerhead" due to its physical
configuration. The vapor is then discharged through the vapor
delivery head 118 and is deposited on a semiconductor substrate 120
such as a silicon wafer. The semiconductor substrate 120 is
positioned on a susceptor unit 122 during the deposition process as
is understood by those of ordinary skill in the art.
[0007] One problem with the above described deposition chamber 100
is that the chamber body 102 is maintained at a temperature which
is lower than that of the heated vapor plumbing 110. For example,
the heated vapor plumbing 110 may be maintained at a temperature of
approximately 140 to 160.degree. C. while the chamber body 102 is
maintained at a temperature of approximately 45 to 65.degree. C.
The reduced temperature of the chamber body 102 causes, through
heat transfer, the temperature of feedthrough device 108 to also be
lower than that of the heated vapor plumbing 110. The temperature
differential between the feedthrough device 108 and the heated
vapor plumbing 110 may cause condensation to occur within the vapor
delivery path 107 as the vapor passes through the feedthrough 108.
Newly utilized organometallic precursors are particularly
susceptible to such condensation due to their relatively low vapor
pressures.
[0008] The occurrence of condensation within the feedthrough 108
may negatively impact the chemical vapor deposition process in
various ways. For example, the condensation may result in
particulate contaminants flowing through the vapor delivery path
107 and being deposited on the surface of the substrate or wafer
120. Introduction of such particulates ultimately results in a
defective semiconductor wafer or other substrate 120 which is
unsuited for use in subsequent semiconductor packaging
processes.
[0009] Additionally, the condensation may cause clogging or
material build-up within the feedthrough device 108 as well as in
the vapor plumbing 116 positioned downstream therefrom along the
vapor delivery path 107. Such clogging may have a deleterious
effect on the flow characteristics of the vapor passing
therethrough. Additionally, material build-up may have a corrosive
effect on the feedthrough device 108 and vapor plumbing 116.
[0010] While it is possible to route the heated vapor plumbing 110
around the chamber body 102 such that it connects directly through
the lid 104 to the vapor delivery head 118 (thereby eliminating the
feedthrough device 108 and additional vapor plumbing 116), in order
to provide continual heat to the flowing vapor along the vapor
delivery path 107, such a configuration is undesirable for various
reasons.
[0011] For example, removal of the lid 104 from the chamber body
102 would require mechanical disconnection of the heated vapor
plumbing 110. This would increase the amount of time required to
service and maintain the CVD chamber 100. Perhaps even more
significantly, mechanical disconnection of the heated vapor
plumbing 110 would increase the potential for contamination the CVD
process and the products produced thereby. Such increased potential
for contamination results from the fact that the CVD chamber 100 is
conventionally located and operated in a plenum 124 adjacent a
clean room (not shown) which may be separated by a barrier 126 from
a mechanical room 128. Wafers 120 are passed from the adjacent
clean room into the CVD chamber 100 for processing. The
implementation of a heated vapor line running exterior to the
chamber body 102 in the plenum 124 would require increased
maintenance activities within the plenum area 124 resulting in the
increased likelihood of particulates and contaminants entering the
plenum area 124, or possibly even into the adjacent clean room,
each time repair or maintenance is required.
[0012] Additionally, the repeated connection and disconnection of
the heated gas plumbing (i.e., from the lid 104) leads to the
degradation of the mechanical connection. For example, a
conventional mechanical connection used in chemical delivery
systems includes a VCR.RTM. metal gasket face seal fitting. The
VCR.RTM. fitting provides for the compression of a metal (or
sometimes polymer) gasket between two opposing toroid surfaces.
After repeated compression (i.e., resulting from repeated
disconnection and connection of the piping) the toroid surfaces
will flatten out and ultimately fail to seal. This necessitates
costly replacement of the fitting and may possibly require the
fabrication and welding of new piping hardware.
[0013] In view of the shortcomings in the art, it would be
advantageous to provide a deposition chamber which allowed for the
use of organometallic precursors having relatively low vapor
pressures without condensation of such organometallic precursors
occurring during delivery of the vapor to the chamber.
[0014] It would also be advantageous to provide a method of
modifying existing deposition chambers to allow the use of
organometallic precursors therewith. Particularly, it would be
advantageous to provide a method of converting a chemical vapor
deposition chamber configured for use with conventional precursors
into an atomic layer deposition chamber or a chemical vapor
deposition chamber suited for use with organometallic
precursors.
SUMMARY OF THE INVENTION
[0015] In accordance with one aspect of the invention, a
feedthrough device is provided for delivering vapor through the
chamber body of a deposition chamber. The feedthrough device
includes a longitudinal body section having a first end and a
second end. A bore or lumen is defined within the longitudinal body
and extends longitudinally therethrough from the first end to
second end for delivering an amount of vapor therethrough.
[0016] A heating device associated with the longitudinal body of
the feedthrough device is oriented and configured to heat the
feedthrough device to a desired temperature and maintain the
temperature thereof. The feedthrough device, including the
longitudinal body and associated heating device, is configured to
be complementarily received within an interior portion of the
chamber body.
[0017] The feedthrough device is further configured to be sealingly
coupled with vapor plumbing externally located relative to the
chamber body. The vapor plumbing and feedthrough device
cooperatively define a vapor delivery path through which vapor is
carried to a cavity within the chamber body for deposition on a
substrate such as a silicon wafer.
[0018] The feedthrough device may be formed of stainless steel or
some other material exhibiting good thermal conductivity and
corrosion resistance so as to efficiently transfer the heat from
the heating device through the body of the feedthrough device and
ultimately to the vapor passing through the bore thereof.
[0019] In accordance with another aspect of the invention, a
deposition chamber is provided which may be suitable for use in
conjunction with either a chemical vapor deposition process or an
atomic layer deposition process. The deposition chamber includes a
chamber body having a chamber cavity defined therein for receipt of
a substrate such as a silicon wafer to have a material deposited
thereon. A chamber lid is configured to enclose the chamber cavity
of the chamber body in cooperation with the chamber body. A vapor
delivery path is defined to carry vapor from a vapor source through
the chamber body to a vapor delivery head within the chamber
cavity. A feedthrough device serves to define a portion of the
vapor delivery path which extends through the chamber body. To
protect against potential condensation of the vapor, the
feedthrough device includes an associated heating device to
maintain the temperature of the feedthrough device, and the vapor
passing therethrough, at a desired temperature.
[0020] The deposition chamber may include additional features to
help maintain the temperature of the vapor as it travels along the
vapor delivery path. For example, the deposition chamber may
include a section of vapor plumbing interposed between the
feedthrough device and the vapor delivery head. The section of
vapor plumbing may be insulated to protect against heat loss
therefrom. Additionally, the feedthrough device may be thermally
insulated with respect the chamber body to increase the efficiency
of the heating device associated with the feedthrough device.
[0021] In accordance with another aspect of the invention, a method
is provided for converting a chemical vapor deposition chamber
having a chamber body, a chamber lid, and a feedthrough device
positioned in a portion of the chamber body, into an atomic layer
deposition chamber. The method includes removing the feedthrough
device from the chamber body and replacing it with a heated
feedthrough device. The heated feedthrough device may be a new,
similarly shaped feedthrough device having a heating device
associated therewith. Alternatively, the heated feedthrough device
may comprise the original feedthrough device modified to include an
associated heating device therewith.
[0022] In accordance with yet another aspect of the invention, a
method is provided for delivering vapor to a vapor delivery head in
a deposition chamber. The method includes providing a source of
vapor and defining a vapor delivery path between the source of
vapor and the vapor delivery head. Defining the vapor delivery path
includes providing a first section of plumbing between the vapor
source and the chamber body of the deposition chamber.
Additionally, a feedthrough device is provided within a portion of
the chamber body and is sealingly coupled to the first section of
plumbing. A second section of plumbing is provided between the
feedthrough device and the vapor delivery head and is accordingly
coupled with the feedthrough device. Vapor is introduced into the
vapor delivery path from the vapor source. The first section of
vapor plumbing and the feedthrough device are heated to eliminate
the potential for condensation of the vapor as it travels through
the vapor delivery path.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0023] The foregoing and other advantages of the invention will
become apparent upon reading the following detailed description and
upon reference to the drawings in which:
[0024] FIG. 1 is a partial cross section of a conventional chemical
vapor deposition chamber;
[0025] FIG. 2 is a partial cross section of an exemplary deposition
chamber according to one embodiment of the present invention;
[0026] FIG. 3 shows a side view of an exemplary heating device for
use with the deposition chamber of FIG. 2; and
[0027] FIGS. 4A and 4B show a side view and end view respectively
of an exemplary feedthrough device according to certain aspects of
the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0028] Referring to FIG. 2, a deposition chamber 200 according to
one embodiment of the present invention is shown. It is noted that
the deposition chamber 200 may be a chemical vapor deposition (CVD)
chamber or an atomic layer deposition (ALD) chamber. Either type of
chamber may be the subject of the present invention and thus, the
invention shall generally refer to a deposition chamber 200 without
being specifically designated as a CVD or ALD type chamber.
[0029] The deposition chamber 200 includes a chamber body 202 and a
chamber lid 204. The chamber lid 204 is removable from the chamber
body 202 for purposes of accessing and maintaining the chamber
interior including the chamber cavity 206. A vapor delivery path
207 is formed through the chamber body 202 using a feedthrough
device 208 disposed in a bore 209 in the chamber body 202. The
vapor delivery path 207 connects to the heated vapor plumbing 210,
and an associated vapor source 211, at the lower side of the
chamber at one end 212 of the feedthrough device 208. The
feedthrough device 208 is also coupled with additional vapor
plumbing 216 via the chamber lid 204 at the second end 214 of the
feedthrough device 208. The vapor delivery path 207 ultimately
leads to a shower, or vapor delivery head 218 for discharging the
vapor into the chamber cavity 206 for deposition onto a substrate
220 such as a silicon wafer which is positioned on a susceptor unit
222. The susceptor unit 222 may be mobile to assist in receiving
individual substrates 220 from a location exterior the deposition
chamber 200 and subsequently positioning the received substrate 220
for the deposition process. The susceptor unit 222 may also include
heating mechanisms for heating the substrate 220 during the
deposition process as will be understood and appreciated by those
of ordinary skill in the art.
[0030] It is noted that the deposition chamber 200 is located in an
interstitial space such as a plenum 224 and that a barrier 226
separates the deposition chamber 200 from a mechanical or
maintenance room 228. As is understood by those of ordinary skill
in the art, it is desirable to locate various connections and
equipment, such as the vapor plumbing 210, in the maintenance room
228 so as to reduce the likelihood of introducing particulates and
contaminants within the plenum 224 or an adjacent clean room (not
shown).
[0031] Still referring to FIG. 2, the vapor delivery path 207
travels through the chamber body 202 via the feedthrough device 208
and then through the chamber lid 204. A pair of seals 230, 232,
such as o-rings, are respectively located to create a fluid tight
seal between the second end 214 of the feedthrough device 208 and
the chamber lid 204 and chamber body 202 when the chamber lid 204
is in a closed position. The feedthrough device 208 may be coupled
to the heated vapor plumbing 210 by use of a coupling 236. One
exemplary coupling includes a VCR.RTM. metal gasket face seal
fitting available from Swagelok.RTM. whose corporate offices are
located at 29500 Solon Road, Solon, Ohio 44139. Of course, other
couplings and connecting devices may be used to couple the
feedthrough device 208 to the heated vapor plumbing 210 as is
understood by those of ordinary skill in the art.
[0032] The vapor delivery path 207 formed by the above-described
arrangement allows for efficient maintenance and service of the
deposition chamber 200 since the chamber lid 204 may be removed
without the disconnection of any external vapor plumbing which
would otherwise be fixedly located and coupled to the chamber lid
204 in a manner preventing raising of the chamber lid 204 without
prior disconnection of the vapor plumbing. For example, using the
configuration of the present invention, the chamber lid 204 may be
removed by rotating it about a hinged connection 234 in order to
access the chamber cavity 206. When the chamber lid 204 is closed,
the vapor delivery path 207 will be restored with the seals 230 and
232 again, respectively forming a fluid tight connection between
the feedthrough device 208 and chamber lid 204 and chamber body
202. Such simple access would not be possible with fixedly located
vapor plumbing attached to the chamber lid 204.
[0033] It is noted that the vapor delivery path 207 shown in FIG. 2
is exemplary and need not include the exterior section of vapor
plumbing 216 located on the chamber lid 204. Alternatively, for
example, a vapor delivery path may include plumbing which is
entirely contained in an interior section of the chamber lid 204 as
the path extends from the feedthrough device 208 to the vapor
delivery head 218. Such a configuration would still allow access to
interior of the deposition chamber 200 without requiring mechanical
connection and disconnection of hard piping within the plenum 224.
However, such a configuration may also prove to be more difficult
and expensive to fabricate than the embodiment depicted in FIG.
2.
[0034] A heating device 238 is utilized in conjunction with the
feedthrough device 208 to maintain the temperature of the
feedthrough device 208 and ultimately maintains the temperature of
the vapor passing therethrough, at a predetermined level.
Desirably, the heating device 238 maintains the temperature of the
feedthrough device 208 at a temperature which is elevated relative
to the temperature of the chamber body 202 and at a temperature
similar to that of the heated vapor plumbing 210. The heating
device 238 enters from the mechanical or maintenance room 228 into
the chamber body 202 at the same location where the feedthrough
device 208 is coupled with the heated vapor plumbing 210.
[0035] Referring to FIG. 3, an exemplary heating device 238 may
include a cable heater, otherwise referred to as a resistance
heater element, having a first unheated section 240 and a second
heated section 242. Heat is provided from a source of alternating
current (AC) via two leads 244 which may be configured to operate
at 120 VAC and 315 W. The leads 244 extend into the resistance
heater element where they are wrapped in a stainless steel, cold
formable sheath 246 such that the heating device may be shaped and
configured in a desired manner. A second pair of sensor leads 248
are also wrapped in the sheath 246 and are connected to a
temperature sensing device 250 such as a thermocouple located about
midway along the second heated section 242. The exemplary heating
device 238, including sheath 246, may be approximately 0.125'' in
diameter and have a length of approximately 31''. Of the 31''
length, the unheated section 240 may include 4'' and the heated
section 242 may include 27''. Such an exemplary cable heater is
available from Watlow Electric Manufacturing Company with offices
at 12001 Lackland Road, St. Louis, Mo. 63146 as part number
125FH031AX-1148.
[0036] It is noted that heating devices exhibiting other
configurations, dimensions and constructions may be utilized with
the present invention. For example, the sheath need not be formed
of stainless steel, but may be formed of other thermally conductive
materials. Additionally, the diameter and length of the heating
device 238, as well as the proportions of the heated and unheated
sections 242, 240 may be varied to suit implementation with
feedthrough devices 208 of varied design. Additionally, electrical
characteristics of the resistance leads 244 may vary depending upon
specific implementations, as will be appreciated by those of
ordinary skill in the art.
[0037] Referring to FIGS. 4A and 4B, a feedthrough device 208
configured for cooperative use with the heating device 238, (FIGS.
2 and 3) is shown. The feedthrough device 208 includes a bore or
lumen 252 extending longitudinally therethrough and which forms a
part of the vapor delivery path 207. The feedthrough device 208
further includes a shoulder portion 254 at its upper end. The
shoulder portion 254 serves to locate and position the feedthrough
device 208 within the chamber body 202. Additionally, as seen the
FIG. 4B, one or more channels or grooves 256 may be formed in the
top and bottom surfaces 254A and 254B of the shoulder portion 254
to accommodate o-rings or other types of seals 230, 232 (see FIG.
2).
[0038] A longitudinal body portion 258 makes up the majority of the
feedthrough device 208 and includes a continual helical groove 260
formed on the surface thereof which is configured for receipt of
the heating device 238. The size and pitch of the helical groove
260 may vary but will be determined in part by the size and
configuration of the heating device 238. For example, a feedthrough
device 208 having a longitudinal body portion 258 with a length of
approximately 3.5'' and an outer diameter of approximately 0.75''
might be configured with a helical groove which is approximately
0.128'' and exhibiting a pitch of approximately 0.2'' for receipt
of the exemplary heating device 238 described above herein.
[0039] The helical groove 260 includes a radiused inner portion 262
which serves to complementarily receive the sheath 246 of the
exemplary heating device 238 thereby increasing the area of contact
between the feedthrough device 208 and the heating device 238.
Increased contact between the feedthrough device 208 and heating
device 238 improves the transfer of heat therebetween resulting in
an increased efficiency of the heating device 238 in heating the
vapor passing therethrough.
[0040] The helical groove 260 makes a transition 264 near the
bottom of the longitudinal body portion 258 and extends
longitudinally outwardly through a coupling portion 266 of the
feedthrough device 208. The coupling portion 266 is configured to
be sealingly coupled with heated vapor plumbing 210. For example,
the coupling portion 266 may include a series of threads 268
thereon for coupling the feedthrough device 208 to the heated vapor
plumbing 210 through use of an appropriate fitting or coupling 236
(see FIG. 2).
[0041] The feedthrough device 208 is desirably formed of a material
having a high thermal conductivity such as a metal having a
relatively low impurity content. Such materials may include, for
example, stainless steel or aluminum. Stainless steel and aluminum
are desirable as they also provide protection against corrosion.
Further, it is desirable to select a material which is
metallurgically compatible with the conductive sheath 246 of the
heating device 238 which is to be positioned in the helical groove
260 of the feedthrough device 208.
[0042] It is noted that the heating device 238 may include a sheath
246 which is cold formable, as set forth above, meaning that the
heating device 238 may be formed into the helical groove 260 and
substantially hold its position therein without having to hot work
the heating device 238 or otherwise secure it. However, it may by
desirable in certain cases to adhere the heating device 238, or at
least a portion thereof, to the feedthrough device 208 regardless
of whether a cold formable sheath 246 is being utilized. This may
be accomplished, for example, by using conductive adhesive or by
spot welding the sheath 246 to the feedthrough device 208.
[0043] Referring back to FIG. 2, in operation, the deposition
chamber 200 delivers the vapor from a vapor source 211 through the
heated vapor plumbing 210. As the vapor travels through the
feedthrough device 208 it desirably maintains the same temperature
as when it passes through the heated vapor plumbing 210. However,
the temperature of the feedthrough device 208 is at least kept at a
temperature sufficient to maintain the vapor state of the precursor
material. This is accomplished by virtue of the heating device 238
operated in association with the feedthrough device 208. The
temperature sensing device 250 allows for monitoring of the
temperature at the feedthrough device 208 so that the temperature
may be appropriately altered when required by increasing or
providing power through the leads 244. The vapor further travels
through the chamber lid 204 and vapor plumbing 216 to the vapor
delivery head 218 for deposition on the substrate or wafer 220
without condensation occurring within the vapor delivery path
207.
[0044] It is noted that the vapor plumbing 216 which carries the
vapor substantially from the feedthrough device 208 to the vapor
delivery head 216 may be insulated to curtail any potential heat
loss in that particular section of the vapor delivery path 207.
However, heat loss along that section of the vapor delivery path
207 is considered to be less significant than the potential heat
loss associated with the passage of vapor through the chamber body
202 via the feedthrough device 208.
[0045] Additionally, if desired, a layer of insulation, as shown in
broken lines 213 on FIG. 2, may be disposed within the bore 209
between the interior portion of the chamber body 202 and the
feedthrough device 208 allowing for greater efficiency in heating
the feedthrough device 208 and for further isolation of the
feedthrough device 208 from the temperature of the chamber body
202.
[0046] The present invention further lends itself to various
methods employing the feedthrough device 208 disclosed herein. For
example, a method of delivering vapor from the vapor source 211 to
the vapor delivery head 218 can readily be seen with reference to
FIG. 2. The method includes defining a vapor delivery path 207 by
providing heated vapor plumbing 210 from the vapor source 211 to
the chamber body 202. A feedthrough device 208 is provided and
coupled to the heated vapor plumbing 210. Additional vapor plumbing
216 is provided to extend between the feedthrough device 208 and
the vapor delivery head 218. The feedthrough device 208 is then
heated using heating device 238 so as to eliminate condensation
within the vapor delivery path 207 caused by cooling of the vapor
due to temperature differentials between the chamber body 202 and
the vapor as it travels through the feedthrough device 208.
[0047] Additionally, the use of a feedthrough device 208 in
combination with the heating device 238 according to the present
invention lends itself to a method of converting a CVD chamber to
an ALD chamber, the ALD chamber requiring greater temperature
control to maintain the associated precursors in a vapor state. The
method of converting a CVD chamber to an ALD chamber includes
removing an unheated feedthrough device from the CVD chamber body
and replacing it with a heated feedthrough device. The heated
feedthrough device may be either a new feedthrough device or the
original feedthrough device modified in accordance with the present
invention to allow heating thereof while positioned within the
chamber body. Thus, the present invention provides an easy and
economical means of updating and converting existing equipment in
lieu of complete replacement of the same.
[0048] While the invention may be susceptible to various
modifications and alternative forms, specific embodiments have been
shown by way of example in the drawings and have been described in
detail herein. However, it should be understood that the invention
is not intended to be limited to the particular forms disclosed.
Rather, includes all modifications, equivalents, and alternatives
falling within the spirit and scope of the invention as defined by
the following appended claims.
* * * * *