U.S. patent application number 13/269372 was filed with the patent office on 2013-04-11 for material delivery system and method.
This patent application is currently assigned to Taiwan Semiconductor Manufacturing Company, Ltd.. The applicant listed for this patent is Yen-Yu Chen, Ke-Chih Liu, Chia-Ming Tsai. Invention is credited to Yen-Yu Chen, Ke-Chih Liu, Chia-Ming Tsai.
Application Number | 20130089934 13/269372 |
Document ID | / |
Family ID | 48042332 |
Filed Date | 2013-04-11 |
United States Patent
Application |
20130089934 |
Kind Code |
A1 |
Liu; Ke-Chih ; et
al. |
April 11, 2013 |
Material Delivery System and Method
Abstract
A system and method for controlling saturated vapor pressure of
a precursor material is provided. An embodiment comprises
generating a calibration curve and utilizing the calibration curve
to control a temperature of the precursor material in order to
control its saturated vapor pressure. Alternatively, the
calibration curve may be substituted for a real time sensor which
can take readings in real time and adjust the temperature and
saturated vapor pressure based upon the real time readings.
Inventors: |
Liu; Ke-Chih; (Hsin-Chu,
TW) ; Tsai; Chia-Ming; (Zhubei City, TW) ;
Chen; Yen-Yu; (Taichung City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Liu; Ke-Chih
Tsai; Chia-Ming
Chen; Yen-Yu |
Hsin-Chu
Zhubei City
Taichung City |
|
TW
TW
TW |
|
|
Assignee: |
Taiwan Semiconductor Manufacturing
Company, Ltd.
Hsin-Chu
TW
|
Family ID: |
48042332 |
Appl. No.: |
13/269372 |
Filed: |
October 7, 2011 |
Current U.S.
Class: |
438/5 ; 118/692;
156/345.26; 257/E21.53 |
Current CPC
Class: |
H01L 21/67248 20130101;
H01L 22/12 20130101; C23C 16/4482 20130101; C23C 16/46 20130101;
C23C 16/52 20130101; C23C 16/4481 20130101; H01L 21/02104
20130101 |
Class at
Publication: |
438/5 ; 118/692;
156/345.26; 257/E21.53 |
International
Class: |
H01L 21/66 20060101
H01L021/66; C23C 16/52 20060101 C23C016/52; C23F 1/08 20060101
C23F001/08; C23C 16/448 20060101 C23C016/448 |
Claims
1. A semiconductor manufacturing system comprising: a precursor
canister with a heater; and a controller configured to
automatically adjust the heater based at least in part upon an
indication of a vapor pressure.
2. The semiconductor manufacturing system of claim 1, wherein the
indication of the vapor pressure is part of a calibration
curve.
3. The semiconductor manufacturing system of claim 2, wherein the
calibration curve is based upon a series of vapor pressure
measurements.
4. The semiconductor manufacturing system of 2, wherein the
calibration curve is based upon a series of thickness variation
measurements.
5. The semiconductor manufacturing system of claim 1, further
comprising a concentration sensor extending into the precursor
canister and communicably coupled to the controller.
6. The semiconductor manufacturing system of claim 5, wherein the
indication of the vapor pressure is a concentration measurement
from the concentration sensor.
7. The semiconductor manufacturing system of claim 1, further
including a precursor material within the precursor canister, the
precursor material being at least partially in a solid phase.
8. The semiconductor manufacturing system of claim 7, further
including a precursor material within the precursor canister, the
precursor material being at least partially in a liquid phase.
9. The semiconductor manufacturing system of claim 1, wherein the
heater has a first region and a second region, the first region
having a higher resistance than the second region.
10. A semiconductor manufacturing system comprising: a precursor
canister with a vapor region and a raw material region; a heating
jacket around the precursor canister; and a controller coupled to
the heating jacket, the controller configured to receive a measured
indication of a saturated vapor pressure and automatically adjust
the heating jacket based upon the indication of the saturated vapor
pressure.
11. The semiconductor manufacturing system of claim 10, wherein the
indication of the saturated vapor pressure is a measurement of the
vapor pressure of the raw material within the raw material
region.
12. The semiconductor manufacturing system of claim 10, wherein the
indication of the saturated vapor pressure is part of a calibration
curve.
13. The semiconductor manufacturing system of claim 12, wherein the
calibration curve is based upon sampled vapor pressures.
14. The semiconductor manufacturing system of claim 12, wherein the
calibration curve is based upon a thickness variation of
layers.
15. A method of manufacturing a semiconductor device, the method
comprising: applying a first amount of heat to a vapor region of a
precursor canister; measuring an indication of saturated vapor
pressure within the vapor region during the applying the first
amount of heat; and applying a second amount of heat to the vapor
region of the precursor canister, the second amount of heat being
adjusted from the first amount of heat based on the indication of
saturated vapor pressure.
16. The method of claim 15, further comprising generating a
calibration curve from the indication of saturated vapor
pressure.
17. The method of claim 15, wherein the indication of saturated
vapor pressure is a thickness variation of a layer on a
semiconductor wafer.
18. The method of clam 15, wherein the indication of saturated
vapor pressure is a measurement of vapor pressure within the vapor
region of the precursor canister.
19. The method of claim 15, wherein the indication of saturated
vapor pressure is a real-time measurement of vapor pressure within
the precursor canister.
20. The method of claim 15, wherein the applying a first amount of
heat further comprises applying a first voltage to a resistive
heater.
Description
BACKGROUND
[0001] Often, semiconductor manufacturing processes utilize
precursor materials in a gaseous phase as part of the manufacturing
process. However, these precursor materials may arrive at the
semiconductor manufacturer in various forms, such as liquid raw
materials or even solid raw materials. To use these liquid or solid
raw materials in the actual manufacturing processes, these raw
materials may need to be changed into a gaseous phase in order to
be properly controlled and delivered to the various processing
chambers where they can react or otherwise be utilized in the
semiconductor manufacturing process.
[0002] In order to achieve the gaseous forms, the solid or liquid
raw materials may be placed into a raw material canister. Once in
the raw material canister the raw material may begin to change
phase into a gaseous form based in part on the material's
equilibrium between itself and an overlying ambient. One such
measure of equilibrium is the raw material's saturated vapor
pressure, which is dependent at least in part on the temperature of
the material within the raw material canister. When in use, the raw
material within the raw material canister may be heated until the
raw material meets the desired saturated vapor pressure based upon
an equation of the raw material's saturated vapor pressure and
temperature. The heating may be performed, for example, using
heating elements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] For a more complete understanding of the embodiments, and
the advantages thereof, reference is now made to the following
descriptions taken in conjunction with the accompanying drawings,
in which:
[0004] FIG. 1 illustrates a precursor delivery system with a
precursor canister in accordance with an embodiment;
[0005] FIG. 2 illustrates a cross sectional view of the precursor
canister in accordance with an embodiment;
[0006] FIG. 3 illustrates top down view of the precursor canister
in accordance with an embodiment;
[0007] FIG. 4 illustrates a controller that may be used to control
the temperature within the precursor canister in accordance with an
embodiment;
[0008] FIGS. 5A-5B illustrates calibration curves that the
controller may use to control the temperature of the precursor
canister in accordance with an embodiment;
[0009] FIG. 6 illustrates a verification curve which may be used to
verify the calibration curve in accordance with an embodiment;
and
[0010] FIG. 7 illustrates another embodiment that uses a real-time
sensor to control the temperature within the precursor canister in
accordance with an embodiment.
[0011] Corresponding numerals and symbols in the different figures
generally refer to corresponding parts unless otherwise indicated.
The figures are drawn to clearly illustrate the relevant aspects of
the embodiments and are not necessarily drawn to scale.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0012] The making and using of embodiments are discussed in detail
below. It should be appreciated, however, that the embodiments
provide many applicable concepts that can be embodied in a wide
variety of specific contexts. The specific embodiments discussed
are merely illustrative of specific ways to make and use the
embodiments, and do not limit the scope of the embodiments.
[0013] The embodiments will be described with respect to
embodiments in a specific context, namely a precursor canister for
a semiconductor manufacturing process. The embodiments may also be
applied, however, to other precursor delivery systems.
[0014] With reference now to FIG. 1, there is shown a precursor
delivery system 100 that may be used to deliver precursor materials
to a semiconductor processing chamber 102. The semiconductor
processing chamber 102 may be a chamber utilized to deposit
materials onto a semiconductor wafer 104. In a particular
embodiment, the semiconductor processing chamber 102 may be
utilized in an atomic layer deposition (ALD) process to form a
layer of tantalum nitride (TaN--not individually shown separate
from the semiconductor wafer 104) onto the semiconductor wafer
104.
[0015] In an ALD process thin films such as the layer of TaN may be
formed on the semiconductor wafer 104 using a self-limiting
process, such that atomic layers of material are deposited
sequentially using a series of pulses of precursor materials. For
example, a first precursor may be introduced into the semiconductor
processing chamber 102 and a layer of this first precursor may be
adsorbed and reacted onto the semiconductor wafer 104. Excess first
precursor may be pumped out and a second precursor may be
introduced to react with the first precursor on the semiconductor
wafer 104 to form a monolayer of the desired material (e.g., the
layer of TaN) via a self-limiting reaction. This process may be
repeated to build up successive monolayers until a desired
thickness is achieved.
[0016] However, as one of ordinary skill in the art will recognize,
the ALD process to form the layer of TaN is merely an illustrative
example of a process that may utilize the semiconductor processing
chamber 102. Other processes that utilize precursor materials may
be performed in the semiconductor processing chamber 102, such as
chemical vapor deposition (CVD), physical vapor deposition (PVD),
various types of etching processes, combinations of these, or the
like, may alternatively be utilized. These processes and any other
process that utilizes gaseous phase precursor materials may
alternatively be performed within the semiconductor processing
chamber 102, and all such processes are fully intended to be
included within the scope of the embodiments.
[0017] The precursor delivery system 100 supplies the desired
precursor materials to the semiconductor processing chamber 102
through a final delivery line 101. The precursor delivery system
100 may also help to control the rate of delivery and pressure of
the semiconductor processing chamber 102 by controlling the inflow
of gas through the final delivery line 101. Furthermore, while only
a single precursor delivery system 100 is illustrated in FIG. 1,
this is done for simplicity, as more than one precursor delivery
system 100 may be attached to the semiconductor processing chamber
102 in order to provide the different number and types of precursor
materials desired for the desired process.
[0018] In an embodiment the precursor delivery system 100 may
include a carrier gas supply 103, a flow controller 105, and a
precursor canister 107. The carrier gas supply 103 may supply a gas
that may be used to help "carry" the precursor gas to the
semiconductor processing chamber 102. The carrier gas may be an
inert gas or other gas that does not react with the precursor
material or other materials within the system. For example, the
carrier gas may be helium (He), argon (Ar), nitrogen (N.sub.2),
hydrogen (H.sub.2), combinations of these, or the like, although
any other suitable carrier gas may alternatively be utilized.
[0019] The carrier gas supply 103 may be vessel, such as a gas
storage tank, that is located either locally to the semiconductor
processing chamber 102 or remotely from the semiconductor
processing chamber 102. Alternatively, the carrier gas supply 103
may be a facility that independently prepares and delivers the
carrier gas to the flow controller 105 of the precursor delivery
system 100 and elsewhere, such as other precursor delivery systems
(not separately shown). Any suitable source for the carrier gas may
be utilized as the carrier gas supply 103, and all such sources are
fully intended to be included within the scope of the
embodiments.
[0020] The carrier gas supply 103 may supply the desired carrier
gas to the flow controller 105 through a first line 113. The flow
controller 105 may be utilized to control the flow of the carrier
gas to the precursor canister 107 and to the semiconductor
processing chamber 102, thereby helping to control the pressure
within the semiconductor processing chamber 102. The flow
controller 105 may be, e.g., a proportional valve, a modulating
valve, a needle valve, a pressure regulator, a mass flow
controller, combinations of these, or the like. However, any
suitable method for controlling and regulating the flow of the
carrier gas to the semiconductor processing chamber 102 may be
utilized, and all such methods are fully intended to be included
within the scope of the embodiments. In an embodiment the carrier
gas supply 103 may control the flow of carrier gas to between about
100 sccm and about 1300 sccm, such as about 800 sccm.
[0021] The flow controller 105 may supply the controlled carrier
gas to the precursor canister 107 through a second line 106. The
precursor canister 107 may be utilized to supply a desired
precursor to the semiconductor processing chamber 102 and may be
located between a first valve 108 and a second valve 110 that may
be used to isolate the precursor canister 107 from inflowing and
outflowing streams. By isolating the precursor canister 107 from
the process streams, the precursor canister 107 may be removed from
the process, either physically or functionally, so that
maintenance, replacing the precursor material, or other off-line
work may be performed on the precursor canister 107 while it is not
actively connected to the rest of the precursor delivery system
100. A third valve 112 may be connected between the second valve
110 and the semiconductor processing chamber 102 in order to make
sure that atmospheric gases do not enter the semiconductor
processing chamber 102 while the precursor canister 107 has been
removed.
[0022] FIG. 2 illustrates in greater detail the precursor canister
107 between the flow controller 105 and the semiconductor
processing chamber 102. The precursor canister 107 may comprise a
chamber 201 with a vapor region 203 and a raw material region 205.
In an embodiment a raw material 204 may be placed into the raw
material region 205 of the chamber 201. Once in the raw material
region 205 of the chamber 201, thermodynamic equilibrium may be
used to drive portions of the raw material 204 into the gaseous
phase and enter the vapor region 203 of the chamber 201, where it
may be picked up and carried by the carrier gas from the flow
controller 105 as the carrier gas flows around baffles 219
(discussed further below with respect to FIG. 3) located within the
vapor region 203 of the chamber 201.
[0023] The chamber 201 may be any desired shape that may be
suitable for vaporizing (if the raw material 204 is a liquid) or
sublimating (if the raw material 204 is a solid) the raw material
204. In the embodiment illustrated in FIG. 2 and FIG. 3 (described
below), the chamber 201 has a cylindrical sidewall and a bottom.
However, the chamber 201 is not limited to a cylindrical shape, and
any other suitable shape, such as a hollow square tube, an
octagonal shape, or the like, may alternatively be utilized.
Furthermore, the chamber 201 may be surrounded by a housing 207
made of material that is inert to the various process materials. As
such, while the housing 207 may be any suitable material that can
withstand the chemistries and pressures involved in the process, in
an embodiment the housing 207 may be steel, stainless steel,
nickel, aluminum, alloys of these, combinations of these, and
like.
[0024] The chamber 201 may also have a lid 209 to enclose the
chamber 201. The lid 209 may be attached to the housing 207
utilizing, e.g., a seal such as an o-ring, a gasket, or other
sealant in order to prevent leakage from the chamber 201 while at
the same time allowing the lid 209 to be removed for access to the
chamber 201 within the interior of the housing 207. Alternatively,
the lid 209 may be attached by welding, bonding, or adhering the
lid 209 to the housing 207 in order to form an air-tight seal and
prevent any leakage.
[0025] An inlet port 215 and an outlet port 217 may provide access
to the chamber 201 in order to receive carrier gas from the flow
controller 105 (see FIG. 1) and output a carrier gas/precursor gas
mixture to the semiconductor processing chamber 102, respectively.
The inlet port 215 and outlet port 217 may be formed in the lid 209
of the chamber 201 (as illustrated in FIG. 2) or may alternatively
be formed through the sidewalls of the chamber 201. In an
embodiment the inlet port 215 and outlet port 217 may also include
various valves and fittings (not shown for clarity) to facilitate
removal and replacement of the chamber 201.
[0026] The raw material region 205 may be utilized to store and
prepare the raw material 204 from which a desired process gas may
be formed. The raw material 204 may be any suitable raw material
that can generate a process precursor in a gaseous form either
through vaporization or sublimation. For example, if the raw
material 204 is a solid material, the raw material 204 may
sublimate from the solid phase to a gaseous phase or melt and then
vaporize to a gaseous phase. Alternatively, if the raw material 204
is a liquid, the raw material 204 may simply vaporize to a gaseous
phase.
[0027] In the embodiment wherein an ALD process is utilized to form
a layer of TaN, the raw material 204 may be a solid material such
as pentakis(dimethylamido)tantalum (PDMAT) and the raw material 204
may be placed within the raw material region 205 of the chamber
201. While the raw material 204 rests in the raw material region
205, the raw material 204 may sublimate to a gaseous form and
accumulate within the vapor region 203 located over the raw
material region 203. As such, the solid PDMAT may provide a process
gas for the carrier gas to pick up and utilize in the semiconductor
processing chamber 102 (as described in greater detail below).
[0028] However, as one of ordinary skill will recognize,
utilization of solid PDMAT is not the only raw material 204 that is
solid and that may be placed within the raw material region 205 of
the chamber 201. Any solid precursor that may generate a gaseous
process gas that may be used for any suitable semiconductor
manufacturing process may also be utilized, and such solid
precursors may include, e.g., xenon difluoride, nickel carbonyl,
tungsten hexacarbonyl, and the like. These and any other suitable
raw material 204 that is solid and that can generate a gaseous
process precursor are fully intended to be included within the
scope of the embodiments.
[0029] Furthermore, the scope of the embodiments is not intended to
be limited to a raw material 204 that is solid as a raw material
204 of any suitable phase that may be used as a precursor material
within a semiconductor manufacturing process may alternatively be
placed within the raw material region 205. In other embodiments the
raw material 204 may comprise a liquid raw material such as
tetrakis(diethylamido)titanium (TDMAT), tertbutylimino
tris(diethylamido)tantalum (TBTDET),
pentakis(ethylmethylamido)tantalum (PE-MAT), and the like. These
and any other suitable liquid raw materials that can generate a
gaseous phase precursor are fully intended to be included within
the scope of the embodiments.
[0030] A heater 213 controlled by a controller 211 (discussed
further below with respect to FIG. 4) may be placed around the
chamber 201 in order to adjust the thermodynamic equilibrium of the
raw material 204 and help drive the raw material 204 into a gaseous
phase and into the vapor region 203 of the chamber 201. The amount
of the raw material 204 that may be transferred to the desired
gaseous phase and the rate at which it may be transferred to the
gaseous phase is related to the thermodynamic equilibrium and may
be represented by a saturated vapor pressure of the raw material
204 itself. In the embodiment in which the raw material 204 is
PDMAT, the initial saturated vapor pressure (P, in mmHg) of PDMAT
may have the following relation to the temperature (T, in Kelvin)
as expressed in Equation 1:
Log 10 P ( mmHg ) = 11.30 - 4125 T ( K ) Eq . 1 ##EQU00001##
As illustrated, by increasing the temperature of the raw material
204, the saturated vapor pressure of the raw material 204 may be
increased and more of the raw material 204 may be driven into the
gaseous phase and the vapor region 203 of the chamber 201, thereby
providing more gaseous process gas.
[0031] Additionally, the heater 213 may be configured to generate a
temperature gradient within the chamber 201. For example, the
heater 213 may be utilized to generate a temperature gradient with
a higher temperature in the vapor region 203 and a lower
temperature in the raw material region 205. As solid materials tend
to condense back from the gaseous phase in colder regions of the
chamber 201, this temperature gradient may be utilized to help any
raw material 204 that phase changes back to a solid or liquid phase
condense in the raw material region 205 instead of condensing in
the vapor region 203. This helps to keep the vapor region 203 clear
of condensing solids and liquids, thereby keeping more gaseous
vapors in the vapor region 203.
[0032] The temperature gradient may be generated by configuring the
heater 213 to generate more heat for the vapor region 203 and less
heat for the raw material region 205. For example, in an embodiment
in which the heater 213 is a resistive heater, the heater 213 may
be configured to have a higher resistance adjacent to the vapor
region 203, thereby leading to a larger generation of heat adjacent
to the vapor region 203 than adjacent to the raw material region
205. In an embodiment the temperature gradient between the vapor
region 203 and the raw material region 205 may be between about
5.degree. C. and about 30.degree. C., such as about 15.degree. C.
In a specific embodiment the heater 213 may be utilized to provide
a temperature of about 73.degree. C. to the raw material region 205
and a temperature of about 88.degree. C. to the vapor region
203.
[0033] Additionally, the heater 213 may have temperature sensors
221 in order to provide heating information to the controller 211.
The temperature sensors 221 may be, e.g., a thermocouple installed
within the heater 213 to monitor the temperature of the heater 213
adjacent to the vapor region 203 and adjacent to the raw material
region 205 of the chamber 201. However, any suitable type of sensor
may alternatively be utilized to measure the temperature of the
heater 213 and transmit that measurement to the controller 211.
[0034] Optionally, the chamber 201 may also include other heating
and cooling devices (not shown) that may be utilized to help form
the temperature gradient. For example, the chamber 201 may include
a cooling plate located at the bottom of the chamber 201 to lower
the temperature of the raw material region 205. Additionally, the
first valve 108, the second valve 110, the inlet port 215, and the
outlet port 217 may also be heated with, e.g., resistive heating
tape or other heating elements. These and any other type of
temperature controls are fully intended to be included within the
scope of the embodiments.
[0035] FIG. 3 illustrates a top down view of the precursor canister
107 along line A-A' in FIG. 2 (with the outlet port 217 also shown
using a dashed circle for clarity) and also illustrates a path that
the carrier gas may travel through the vapor region 203 of the
chamber 201. As illustrated, the vapor region 203 may also contain
a number of the baffles 219 that may be designed to form a longer
flow path for the carrier gas through the vapor region 203 of the
chamber 201 than a straight line between the inlet port 215 and the
outlet port 217. By forming a longer flow path, the baffles 219 may
also cause the carrier gas to have a longer residence time within
the vapor region 203 of the chamber 201, thereby also increasing
the amount of gaseous precursor gas that the carrier gas will
pick-up and "carry" out the outlet port 217 and to the
semiconductor processing chamber 102.
[0036] The precise number and shape of the baffles 219 and the
carrier gas flow path through the vapor region 203 may be selected
to control the vaporization/sublimation and the flow of the gaseous
precursor material. For example, more baffles 219 may be installed
to form a longer path through the vapor region 203, thereby causing
the carrier gas to have a faster speed through the vapor region
203, or the specific shape of the baffles 219 may be designed to
affect the vaporization/sublimation of the raw material 204 and
help to control the usage of the raw material 204, allowing for
more control of the usage of the raw material 204. As such, while
five baffles 219 are illustrated in FIG. 3 as an illustrative
embodiment, there could be any number and shape of baffles 219
while still remaining within the scope of the embodiments.
[0037] The baffles 219 may be attached to the housing 207 or lid
209 of the chamber 201, or may alternatively be a stand-alone
insert that may be separately placed within the chamber 201.
Additionally, the baffles 219 may be placed so as to extend into
the raw material region 205 and also to prevent the flow of
materials (e.g. the carrier gas and the raw material 204 in a
gaseous phase) between the baffles 219 and the lid 209 of the
chamber 201. Such a placement will cause the carrier gas and raw
material 204 to flow between the baffles 219 instead of over or
around the baffles 219.
[0038] FIG. 4 illustrates in greater detail an embodiment of the
controller 211 that may be utilized to control the heater 213 and,
through the heater 213, control the saturated vapor pressure of the
raw material 204 in the vapor region 203 of the chamber 201. The
controller 211 may be any form of computer processor that can be
used in an industrial setting for controlling process machines or
may alternatively be a general purpose computer platform programmed
for such control of industrial machines. In an embodiment the
controller 211 may comprise a processing unit 401, such as a
desktop computer, a workstation, a laptop computer, or a dedicated
unit customized for a particular application. The controller 211
may be equipped with a display 403 and one or more input/output
components 405, such as sensor inputs, a mouse, a keyboard,
printer, combinations of these, or the like. The processing unit
401 may include a central processing unit (CPU) 406, memory 408, a
mass storage device 410, a video adapter 414, and an I/O interface
416 connected to a bus 412.
[0039] The bus 412 may be one or more of any type of several bus
architectures including a memory bus or memory controller, a
peripheral bus, or video bus. The CPU 406 may comprise any type of
electronic data processor, and the memory 408 may comprise any type
of system memory, such as static random access memory (SRAM),
dynamic random access memory (DRAM), or read-only memory (ROM). The
mass storage device 410 may comprise any type of storage device
configured to store data, programs, and other information and to
make the data, programs, and other information accessible via the
bus 412. The mass storage device 410 may comprise, for example, one
or more of a hard disk drive, a magnetic disk drive, or an optical
disk drive.
[0040] The video adapter 414 and the I/O interface 416 provide
interfaces to couple external input and output devices to the
processing unit 401. As illustrated in FIG. 4, examples of input
and output devices include the display 403 coupled to the video
adapter 414 and the I/O component 405, such as sensors (e.g., the
temperature sensors 221, see FIG. 2), a mouse, keyboard, printer,
and the like, coupled to the I/O interface 416. Other devices may
be coupled to the processing unit 401, and additional or fewer
interface cards may be utilized. For example, a serial interface
card (not shown) may be used to provide a serial interface for a
printer. The processing unit 401 also may include a network
interface 418 that may be a wired link to a local area network
(LAN) or a wide area network (WAN) 420 and/or a wireless link.
[0041] It should be noted that the controller 211 may include other
components. For example, the controller 211 may include power
supplies, cables, a motherboard, removable storage media, cases,
and the like. These other components, although not shown in FIG. 4,
are considered part of the controller 211.
[0042] Operationally, the controller 211 may be utilized to control
the heater 213. For example, when the raw material 205 is initially
placed in the raw material region 205 of the chamber 201 (and
before any degradation or deterioration has occurred), the
controller 211 may control the heater 213 so as to set the
temperature of the heater 213 (and, through a transfer of heat
through the housing 207, the temperature of the chamber 201) to a
desired temperature. In an embodiment which utilizes PDMAT, the
desired temperature may be determined in part from the initial
saturated vapor pressure equation detailed above with respect to
Equation 1. For example, in the embodiment utilizing PDMAT, the
controller 211 may set the heater 213 to have a temperature
gradient, with the temperature adjacent to the vapor region 203
being between about 85.degree. C. and about 95.degree. C., such as
about 88.degree. C., while the temperature adjacent to the raw
material region 205 being between about 68.degree. C. and about
79.degree. C., such as about 73.degree. C. However, the precise
temperatures may vary depending upon the material used, the initial
vapor pressure, and the desired flow rate of raw material 204
desired.
[0043] Additionally, the controller 211 may also be configured to
automatically tune the temperature (and thereby adjust the
saturated vapor pressure of the raw material 204) in order to
compensate for any degradation and deterioration that may occur
over long term, repeated use of the raw material 204. In an
embodiment, as the saturated vapor pressure of the raw material 204
decreases at a particular temperature because of deterioration and
degradation, the controller 211 may automatically compensate for
the reduced saturated vapor pressure by increasing the process
temperature and raising the lowered initial saturated vapor
pressure of the raw material 204. By raising the saturated vapor
pressure through the temperature, the desired concentration of raw
material 204 within the vapor region 203 and, subsequently, the
semiconductor processing chamber 102, may be obtained and kept
consistent throughout the life span of the raw material 204.
[0044] The controller 211 may automatically adjust the temperature
of the heater 213 and adjust the saturated vapor pressure of the
raw material 204 in a number of methods. In a first embodiment a
calibration curve may be generated and then implemented within the
controller 211. In this embodiment an initial sample of raw
material 204 may be placed within the chamber 201 and used over its
life span without compensation from the controller 211. By allowing
the initial sample of raw material 204 to degrade and deteriorate,
an indication of the saturated vapor pressure of the initial sample
of raw material 204 may be taken each time the initial sample of
raw material 204 is used, and the degradation and deterioration can
be charted as the calibration curve.
[0045] FIG. 5A illustrates such a calibration curve in which solid
PDMAT is utilized as the initial sample of raw material 204. In
this type of calibration curve, the indications of the saturated
vapor pressure are samples of the vapor pressure or concentration
of the raw material 204 taken from the vapor region 203 while the
initial sample of raw material 204 was in use. In this calibration
curve, a normalized indication of the vapor pressure is illustrated
on the y-axis and a normalized number of runs is illustrated on the
x-axis.
[0046] However, the calibration curve is not limited to be
generated by measuring the vapor pressure of the raw material 204.
Any other suitable indication of saturated vapor pressure may
alternatively be utilized. FIG. 5B illustrates another calibration
curve which may be generated using another indication of saturated
vapor pressure: the variation of the semiconductor wafers 104 that
are formed during the processes. As a reduced saturated vapor
pressure leads to a reduced mass flow of precursor material, which
in turn can lead to a greater variation in thickness, a larger
variation in thickness of a layer may be utilized as an indication
that the saturated vapor pressure is being degraded. Given this,
the calibration curve may also be generated by utilizing the
initial raw sample of raw material 204 to form layers on the
semiconductor wafer 104 (or series of semiconductor wafers 104),
and then measuring the variation of the thicknesses of these
layers. These data points may then be charted as illustrated in
FIG. 5B (using normalized data for the thickness variations and
wafers) to generate the calibration curve, with the variability
only decreasing after the raw material 204 has been replaced, such
as after 2000 liters.
[0047] After the calibration curve has been generated from the
actual usage of the initial sample of raw material 204, the
calibration curve may be then be input and stored into the
controller 211, which may then use the calibration curve to adjust
the heater 213 for subsequent samples of the raw material 204. For
example, if similar material and process conditions are utilized
for subsequent samples of the raw material 204, then the controller
may, from the calibration curve, known when and how much the
saturated vapor pressure of the raw material 204 has deteriorated
from the initial saturated vapor pressure equation (see, e.g.,
Equation 1). With the calibration curve, the controller 211 may
automatically adjust the temperature of the heater 213 in order to
compensate for the deterioration and degradation. For example, as
the saturated vapor pressure of the raw material 204 deteriorates
from usage, the controller 211 may, based on the calibration curve,
sequentially increase the temperature of the heater 213 between
about 0.5.degree. C. and about 10.degree. C., such as an increase
over the life span of the raw material 204 of about 5.degree. C. In
an embodiment in which the temperature gradient for PDMAT is
initially set at 88.degree. C.-73.degree. C., the controller 211,
based on the calibration curve, may sequentially increase the
temperature gradient about 5.degree. C., to about 93.degree.
C.-78.degree. C., at the end of the life span of the raw material
204.
[0048] Optionally, after the calibration curve has been generated
and implemented within the controller 211, the calibration curve
may be verified during subsequent manufacturing processes by
generating a verification curve such as the verification curve
illustrated in FIG. 6. For example, the verification curve may be
generated by utilizing similar measurements of an indication of
saturated vapor pressure as those described above (e.g., measuring
the vapor pressure or concentration or measuring a variation of the
thickness of a layer formed from the raw material 204). These
indications of saturated vapor pressure may be charted and, if the
indications of saturated vapor pressure remain consistent over the
life span of the raw material 204, as illustrated in FIG. 6, the
calibration curve may be verified. If the indications of saturated
vapor pressure do not remain consistent, modifications to the
calibration curve may be made.
[0049] By having the controller 211 utilize the calibration curve,
the variation in saturated vapor pressure caused by deterioration
and degradation of the raw material 204 may be avoided. As such, a
more constant concentration of the raw material 204 may be
generated over the life span of the raw material 204 in the vapor
region 203 of the chamber 201, and a more even flow of the raw
material 204 may be presented to the semiconductor processing
chamber 102. By having a more consistent concentration variations
in the thickness of the layers formed on the semiconductor wafer
104 may be reduced, leading to more consistent layers and less
chances for problems to occur during the manufacturing of the
semiconductor wafer 104.
[0050] FIG. 7 illustrates another embodiment in which the
controller 211 may adjust the temperature of the heater 213 based
on a real-time sensor 701 instead of a calibration curve. In this
embodiment the real-time sensor 701 may be installed such that it
samples the vapor pressure or concentration of the raw material 204
within the vapor region 203 of the chamber 201 and immediately
relays that information to the controller 211. The real-time sensor
701 may, e.g., be an optical sensor that can measure a
concentration by measuring a reduction in optical radiation (e.g.,
infrared or ultraviolet radiation) due to the absorption of the
radiation by the raw material 204 in the gaseous form. However, any
suitable real-time sensor may alternatively be utilized to measure
the concentration of the raw material 204 as a real-time indication
of the saturated vapor pressure of the raw material 204.
[0051] Once a real-time measurement has been taken by the sensor
701, the measurement may be relayed to the controller 211. The
controller 211 may take this measurement and compare it to a
desired value to determine if there is any deterioration or
degradation that has occurred. If deterioration or degradation has
occurred, the controller 211 may adjust the temperature of the
heater 213 to compensate for the deterioration or degradation.
Subsequent readings from the sensor 701 may be compared to the
desired value in order to see if further adjustments may be
desired.
[0052] In accordance with an embodiment, a semiconductor
manufacturing system comprising a precursor canister with a heater
is provided. A controller is configured to automatically adjust the
heater based at least in part upon an indication of a vapor
pressure.
[0053] In accordance with another embodiment, a semiconductor
manufacturing system comprising a precursor canister with a vapor
region and a raw material region is provided. A heating jacket is
around the precursor canister, and a controller is coupled to the
heating jacket, the controller configured to receive measured
indications of a vapor pressure and automatically adjust the
heating jacket based upon the indication of a saturated vapor
pressure.
[0054] In accordance with yet another embodiment, a method of
manufacturing a semiconductor device comprising applying a first
amount of heat to a vapor region of a precursor canister and
measuring an indication of saturated vapor pressure within the
vapor region during the applying the first amount of heat is
provided. A second amount of heat is applied to the vapor region of
the precursor canister, the second amount of heat being adjusted
from the first amount of heat based on the indication of saturated
vapor pressure.
[0055] Although the embodiments and their advantages have been
described in detail, it should be understood that various changes,
substitutions and alterations can be made herein without departing
from the spirit and scope of the embodiments as defined by the
appended claims. For example, the heater may be a resistive heater
or a steam heater. Additionally, any type of indication of that may
be utilized to provide a description of the saturated vapor
pressure may alternatively be measured.
[0056] Moreover, the scope of the present application is not
intended to be limited to the particular embodiments of the
process, machine, manufacture, composition of matter, means,
methods and steps described in the specification. As one of
ordinary skill in the art will readily appreciate from the
disclosure of the embodiments, processes, machines, manufacture,
compositions of matter, means, methods, or steps, presently
existing or later to be developed, that perform substantially the
same function or achieve substantially the same result as the
corresponding embodiments described herein may be utilized
according to the embodiments. Accordingly, the appended claims are
intended to include within their scope such processes, machines,
manufacture, compositions of matter, means, methods, or steps.
* * * * *