U.S. patent application number 16/551398 was filed with the patent office on 2019-12-19 for in-situ pre-clean for selectivity improvement for selective deposition.
The applicant listed for this patent is Applied Materials, Inc.. Invention is credited to Vikash Banthia, Mei Chang, Feiyue Ma, Kai Wu, Sang Ho Yu.
Application Number | 20190385838 16/551398 |
Document ID | / |
Family ID | 61560307 |
Filed Date | 2019-12-19 |
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United States Patent
Application |
20190385838 |
Kind Code |
A1 |
Wu; Kai ; et al. |
December 19, 2019 |
In-Situ Pre-Clean For Selectivity Improvement For Selective
Deposition
Abstract
Methods to selectively deposit a film on a first surface (e.g.,
a metal surface) relative to a second surface (e.g., a dielectric
surface) by exposing the surface to a pre-clean plasma comprising
one or more of argon or hydrogen followed by deposition. The first
surface and the second surface can be substantially coplanar. The
selectivity of the deposited film may be increased by an order of
magnitude relative to the substrate before exposure to the
pre-cleaning plasma.
Inventors: |
Wu; Kai; (Palo Alto, CA)
; Banthia; Vikash; (Los Altos, CA) ; Yu; Sang
Ho; (Cupertino, CA) ; Chang; Mei; (Saratoga,
CA) ; Ma; Feiyue; (San Jose, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Applied Materials, Inc. |
Santa Clara |
CA |
US |
|
|
Family ID: |
61560307 |
Appl. No.: |
16/551398 |
Filed: |
August 26, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15699110 |
Sep 8, 2017 |
10395916 |
|
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16551398 |
|
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62393022 |
Sep 10, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/28568 20130101;
H01L 21/28562 20130101; H01L 21/28556 20130101; H01L 21/76883
20130101; H01L 21/02074 20130101; H01L 23/53209 20130101; H01L
21/76849 20130101; H01L 21/02697 20130101; H01L 21/02068 20130101;
H01L 21/768 20130101; H01L 23/53266 20130101; H01L 23/53238
20130101 |
International
Class: |
H01L 21/02 20060101
H01L021/02; H01L 21/285 20060101 H01L021/285; H01L 21/768 20060101
H01L021/768 |
Claims
1. A processing platform comprising: a central transfer station
having a robot therein; a pre-clean chamber connected to the
central transfer station; a processing chamber connected to the
central transfer station; and a controller connected to the
pre-clean chamber, the processing chamber, and the robot, the
controller configured to: pre-clean a substrate having a first
surface and a second surface different from the first surface by
exposing the substrate in the pre-clean chamber to a pre-clean
plasma comprising one or more of argon or hydrogen to form a
pre-cleaned substrate; and selectively deposit a metal film on the
pre-cleaned substrate in the processing chamber by chemical vapor
deposition.
2. The processing platform of claim 1, further comprising a factory
interface connected to the central transfer station and the
controller is further configured to control the factory interface
and the robot.
3. The processing platform of claim 2, wherein the central transfer
station is separated from each of the factory interface, the
pre-clean chamber and the processing chamber by a slit valve, the
controller connected to each slit valve and configured to control
opening and closing each slit valve.
4. The processing platform of claim 3, wherein the controller is
configured to move a substrate between and among the factory
interface, the central transfer station, the pre-clean chamber and
the processing chamber.
5. The processing platform of claim 1, wherein the controller is
further configured to ignite the pre-clean plasma from a cleaning
gas.
6. The processing platform of claim 5, wherein the controller is
configured to control at least one of composition, flow rate or
pressure of the cleaning gas.
7. The processing platform of claim 1, further comprising one or
more heating or cooling element within the pre-clean chamber, the
controller connected to the one or more heating or cooling element
and further configured to control a temperature of the substrate
within the pre-clean chamber or a temperature of the pre-clean
chamber.
8. The processing platform of claim 1, wherein the controller is
configured to control at least one of composition, flow rate or
pressure of a deposition gas in the processing chamber.
9. The processing platform of claim 1, wherein the controller is
configured to control a temperature of a susceptor or a substrate
support within the processing chamber and/or a temperature of the
processing chamber.
10. A control system comprising: a processor; a memory coupled to
the processor; and support circuits coupled to the processor,
wherein the control system is configured to: pre-clean a substrate
having a first surface and a second surface different from the
first surface by exposing the substrate to a pre-clean plasma
comprising one or more of argon or hydrogen to form a pre-cleaned
substrate; and selectively deposit a metal film on the pre-cleaned
substrate by chemical vapor deposition.
11. The control system of claim 10, wherein the control system is
further configured to ignite the pre-clean plasma from a cleaning
gas.
12. The control system of claim 11, wherein the control system is
further configured to control at least one of composition, flow
rate or pressure of the cleaning gas.
13. The control system of claim 10, wherein the control system is
further configured to control a temperature of the substrate while
exposed to the pre-clean plasma.
14. The control system of claim 10, wherein the control system is
further configured to selectively deposit the metal film by
controlling at least one of composition, flow rate or pressure of a
deposition gas.
15. The control system of claim 10, wherein the control system is
further configured to control a temperature of the substrate during
selective deposition of the metal film.
16. A computer readable medium including instructions, that, when
executed by a controller of a processing platform, cause the
processing platform to perform the operations of: exposing a
substrate to a pre-clean plasma to form a pre-cleaned substrate;
and selectively depositing a metal film on the pre-cleaned
substrate by chemical vapor deposition.
17. The computer readable medium of claim 16, wherein the
instructions cause the processing platform: to flow a predetermined
composition, flow rate and/or pressure of a cleaning gas; and to
ignite the pre-clean plasma from the cleaning gas.
18. The computer readable medium of claim 16, wherein exposing a
substrate to a pre-clean plasma comprises maintaining the substrate
at a predetermined temperature.
19. The computer readable medium of claim 16, wherein selectively
depositing the metal film comprises maintaining the substrate at a
predetermined temperature.
20. The computer readable medium of claim 16, further comprising
instructions, that, when executed by a controller of a processing
platform, cause the processing platform to move the substrate
between and among a central transfer station, a pre-clean chamber
and a processing chamber of the processing platform.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. patent application
Ser. No. 15/699,110, filed Sep. 8, 2017, now U.S. Pat. No.
10,395,916, issued Aug. 27, 2019, and U.S. Provisional Application
No. 62/393,022, filed Sep. 10, 2016, the entire disclosures of
which are hereby incorporated by reference.
FIELD
[0002] Embodiments of the disclosure generally relate to methods of
selectively depositing a film. More particularly, embodiments of
the disclosure are directed to methods of selectively depositing a
film an in-situ plasma.
BACKGROUND
[0003] Tungsten has been widely used in multiple levels in logic
and memory devices. Typically, CVD W processes provide conformal
tungsten film growth on the substrate where nucleation has started.
As the device scaling continues, there are new applications and
integrations, such as cobalt capping for cobalt contacts, and
copper capping for backend, that may use selective tungsten growth
only on certain area of the pattern.
[0004] During the process flow integration, selective tungsten
processes may lose selectivity due to the prior processing steps.
For example, on a patterned surface after chemical-mechanical
planarization (CMP), severe selectivity loss from >50:1 to
<5:1 has been observed between metal and dielectric surface.
[0005] For some selective cobalt process, an in-situ passivation
process using a surfactant has been developed to improve
selectivity. The passivation layer formed only reacts on dielectric
surfaces instead of copper surface, so cobalt can only grow on
copper substrate instead of on the passivated dielectric, therefore
selectivity is significantly improved. However, current surfactants
will not only passivate the dielectric surface but also the cobalt
surface. Therefore, tungsten cannot grow on the cobalt surface
either, leaving no tungsten growth at all.
[0006] Therefore, there is a need in the art for methods of
selectively depositing a film onto one surface selectively over a
different surface.
SUMMARY
[0007] One or more embodiments of the disclosure are directed to
methods of selectively depositing a film. A substrate having a
first surface and a second surface different from the first surface
is provided. The substrate is exposed to a pre-clean plasma
comprising one or more of argon or hydrogen to form a pre-cleaned
substrate. A metal film is selectively deposited on the first
surface of the pre-cleaned substrate relative to the second
surface.
[0008] Additional embodiments of the disclosure are directed to
methods of selectively depositing a film. A substrate having a
metal surface and a dielectric surface is provided. The metal
surface and the dielectric surface are substantially coplanar. The
substrate is exposed to a pre-clean plasma to form a pre-cleaned
substrate. The pre-clean plasma comprises one or more of argon or
hydrogen at a pressure in the range of about 10 mTorr to about 1
Torr. The pre-cleaned substrate is exposed to deposition conditions
to deposit a metal film. The metal film is deposited with a
selectivity of greater than or equal to about 50:1 on the metal
surface relative to the dielectric surface.
[0009] Further embodiments of the disclosure are directed to
methods of selectively depositing a film. A substrate having a
cobalt surface and a dielectric surface that are substantially
coplanar is provided. The substrate is exposed to a pre-clean
plasma to form a pre-cleaned substrate. The pre-clean plasma
comprises one or more of argon or hydrogen at a pressure in the
range of about 10 mTorr to about 1 Torr and a temperature about
room temperature. The pre-cleaned substrate is exposed to
deposition conditions to deposit a tungsten film with a selectivity
of greater than or equal to about 50:1 on the cobalt surface
relative to the dielectric surface. The deposition conditions
comprise a thermal CVD process using WF.sub.6/H.sub.2 at a
temperature in the range of about 200.degree. C. to about
300.degree. C.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] So that the manner in which the above recited features of
the present disclosure can be understood in detail, a more
particular description of the disclosure, 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 disclosure and are therefore not to be considered limiting of
its scope, for the disclosure may admit to other equally effective
embodiments.
[0011] FIG. 1 shows a schematic cross-sectional view of a substrate
with a first surface and a second surface in accordance with one or
more embodiment of the disclosure;
[0012] FIG. 2 shows a schematic cross-sectional view of the
substrate of FIG. 1 with a metal film deposited thereon without
pre-cleaning;
[0013] FIG. 3 shows a schematic cross-sectional view of the
substrate of FIG. 1 with a metal film deposited thereon with
pre-cleaning in accordance with one or more embodiment of the
disclosure; and
[0014] FIG. 4 shows a processing system in accordance with one or
more embodiment of the disclosure.
DETAILED DESCRIPTION
[0015] Embodiments of the disclosure provide methods to improve
selectivity of a metal deposition process (e.g., tungsten) in the
integration flow, such as post-chemical mechanical planarization
(CMP), using an in-situ pre-clean process. The pre-clean process of
some embodiments comprises exposure to an Ar and/or H.sub.2 plasma
to selectively remove surface damage/contamination from the
dielectric after CMP and also remove/reduce oxides on the metal
surface so that a metal can be deposited on one surface relative to
the other surface. The plasma pressure can be in the range of about
10 mTorr to about 1 Torr. A bias can be applied to improve
selectivity and minimize/eliminate metal lateral growth. After the
in-situ pre-clean, selectivity can be recovered to a level greater
than or equal to about 50:1. Embodiments of the method can be used
for capping layers for metal interconnects, capping on top of metal
vias for post-CMP defect reduction, bottom-up gapfill applications,
and other processes.
[0016] As used in this specification and the appended claims, the
term "substrate" and "wafer" are used interchangeably, both
referring to a surface, or portion of a surface, upon which a
process acts. It will also be understood by those skilled in the
art that reference to a substrate can also refer to only a portion
of the substrate, unless the context clearly indicates otherwise.
Additionally, reference to depositing on a substrate can mean both
a bare substrate and a substrate with one or more films or features
deposited or formed thereon.
[0017] A "substrate" as used herein, refers to any substrate or
material surface formed on a substrate upon which film processing
is performed during a fabrication process. For example, a substrate
surface on which processing can be performed include materials such
as silicon, silicon oxide, strained silicon, silicon on insulator
(SOI), carbon doped silicon oxides, silicon nitride, doped silicon,
germanium, gallium arsenide, glass, sapphire, and any other
materials such as metals, metal nitrides, metal alloys, and other
conductive materials, depending on the application. Substrates
include, without limitation, semiconductor wafers. Substrates may
be exposed to a pretreatment process to polish, etch, reduce,
oxidize, hydroxylate, anneal and/or bake the substrate surface. In
addition to film processing directly on the surface of the
substrate itself, in the present disclosure, any of the film
processing steps disclosed may also be performed on an underlayer
formed on the substrate as disclosed in more detail below, and the
term "substrate surface" is intended to include such underlayer as
the context indicates. Thus for example, where a film/layer or
partial film/layer has been deposited onto a substrate surface, the
exposed surface of the newly deposited film/layer becomes the
substrate surface. What a given substrate surface comprises will
depend on what films are to be deposited, as well as the particular
chemistry used. In one or more embodiments, the first substrate
surface will comprise a metal, and the second substrate surface
will comprise a dielectric, or vice versa. In some embodiments, a
substrate surface may comprise certain functionality (e.g., --OH,
--NH, etc.).
[0018] As used in this specification and the appended claims, the
terms "reactive gas", "precursor", "reactant", and the like, are
used interchangeably to mean a gas that includes a species which is
reactive with a substrate surface. For example, a first "reactive
gas" may simply adsorb onto the surface of a substrate and be
available for further chemical reaction with a second reactive
gas.
[0019] Embodiments of the disclosure provide methods of selectively
depositing a metal film onto one surface over a second surface. As
used in this specification and the appended claims, the term
"selectively depositing" a film on one surface over another
surface, and the like, means that a first amount of the film is
deposited on the first surface and a second amount of film is
deposited on the second surface, where the second amount of film is
less than the first amount of film or none. The term "over" used in
this regard does not imply a physical orientation of one surface on
top of another surface, rather a relationship of the thermodynamic
or kinetic properties of the chemical reaction with one surface
relative to the other surface. For example, selectively depositing
a cobalt film onto a copper surface over a dielectric surface means
that the cobalt film deposits on the copper surface and less or no
cobalt film deposits on the dielectric surface; or that the
formation of the cobalt film on the copper surface is
thermodynamically or kinetically favorable relative to the
formation of a cobalt film on the dielectric surface. Stated
differently, the film can be selectively deposited onto a first
surface relative to a second surface means that deposition on the
first surface is favorable relative to the deposition on the second
surface.
[0020] Embodiments of the disclosure are directed to methods of
selectively depositing a film. FIG. 1 shows a schematic
cross-sectional view of a substrate 10 with a first surface 20 and
a second surface 30. For example, the substrate 10 shown is a
dielectric material so that the second surface 30 is a dielectric
surface. A channel 17 in the substrate 10 is filled with a first
material 15, for example, a metal. The surface of the first
material 15 provides the first surface 20.
[0021] The first surface 20 and the second surface 30 can have
chemistries different than the bulk chemistry of the material
forming the surface. For example, the first material 15 can be a
metal (e.g., cobalt) while the first surface 20 may be an oxidized
cobalt. The surface chemistry of the first surface 20 and the
second surface 30 can be affected by previous processing on the
substrate. For example, a chemical-mechanical planarization (CMP)
process may cause the surfaces to become oxidized, contaminated or
damaged. The oxidation, contamination or damage to the surface can
result in the loss in selectivity.
[0022] In some embodiments, as shown in FIG. 1, the first surface
and the second surface are substantially coplanar. Those skilled in
the art will understand that substantially coplanar means that the
major planes formed by individual surface are within about the same
plane. As used in this regard, "substantially coplanar" means that
the plane formed by the first surface is within .+-.100 .mu.m of
the plane formed by the second surface, measured at the boundary
between the first surface and the second surface. In some
embodiments, the planes formed by the first surface and the second
surface are within .+-.500 .mu.m, .+-.400 .mu.m, .+-.300 .mu.m,
.+-.200 .mu.m, .+-.100 .mu.m, .+-.50 .mu.m, .+-.10 .mu.m, .+-.5
.mu.m, .+-.1 .mu.m, .+-.500 nm, .+-.250 nm, .+-.100 nm, .+-.50 nm,
.+-.10 nm, .+-.1 nm or .+-.0.1 nm.
[0023] In some embodiments, the substrate 10 has been subjected to
a chemical-mechanical planarization (CMP) process. The surface of
the substrate, including the first surface and the second surface,
may have a root-mean-square (RMS) roughness less than or equal to
about 100 nm, 50 nm, 10 nm, 1 nm, 0.5 nm or 0.1 nm.
[0024] FIG. 2 shows a schematic cross-sectional view of the
substrate of FIG. 1 with a metal film 40 deposited thereon. The
selectivity of the metal film 40 is poor, with large areas or
domains deposited on the second surface 30 and the first surface
20. Embodiments of the disclosure provide in-situ methods to
improve the selectivity of the metal film 40. As used in this
manner, "in-situ" means that the substrate is not exposed to air
between pre-cleaning and deposition of the metal film. For example,
the substrate may be positioned in the same processing chamber for
pre-cleaning and film deposition. In some embodiments, the
substrate remains under load-lock conditions for the pre-cleaning
and film deposition, for example, in a cluster tool.
[0025] FIG. 3 shows a schematic cross-sectional view of the
substrate of FIG. 1 with a metal film 40 deposited thereon after
the first surface 20 and second surface 30 have been exposed to the
pre-cleaning process. The selectivity of the metal film 40 for the
first surface 20 is much greater than in FIG. 2 where no
pre-cleaning process was performed.
[0026] To increase the selectivity, the substrate is exposed to a
pre-cleaning process. The term "pre-clean" means prior to
deposition of the metal film on the surface without additional
intervening processing steps (e.g., deposition, annealing,
polishing). The pre-clean process comprises exposing the substrate
to a pre-clean plasma. The pre-clean plasma comprises one or more
of argon or hydrogen. In some embodiments, the pre-clean plasma
comprises argon. In some embodiments, the pre-clean plasma
comprises hydrogen. In some embodiments, the pre-clean plasma
comprises a mixture of hydrogen and argon. In some embodiments, the
pre-clean plasma consists essentially of argon. In some
embodiments, the pre-clean plasma consists essentially of hydrogen.
In some embodiments, the pre-clean plasma consists essentially of a
combination of hydrogen and argon. As used in this regard, the term
"consists essentially of" means than the active plasma species is
greater than or equal to about 95 atomic % of the stated component.
In some embodiments, the pre-clean plasma is greater than or equal
to about 96, 97, 98 or 99 atomic percent of the stated
component.
[0027] The conditions of the pre-clean plasma can be modified
depending on the specific surfaces being cleaning. The pressure of
the pre-clean plasma in some embodiments is in the range of about
10 mTorr to about 30 Torr, or in the range of about 10 mTorr to
about 10 Torr, or in the range of about 20 mTorr to about 5 Torr,
or in the range of about 30 mTorr to about 1 Torr. The temperature
during pre-cleaning in some embodiments is in the range of about
0.degree. C. to about 400.degree. C., or in the range of about room
temperature to about 400.degree. C., or in the range of about room
temperature to about 350.degree. C., or in the range of about room
temperature to about 300.degree. C., or in the range of about room
temperature to about 250.degree. C. As used in this specification
and the appended claims, the term "room temperature" refers to a
temperature in the range of about 20.degree. C. to about 25.degree.
C. In some embodiments, the temperature of the pre-clean plasma is
about room temperature.
[0028] In some embodiments, the pre-clean plasma includes a bias
component applied to the substrate to cause more directionality to
the plasma species. For example a bias of 2 MHz applied to the
wafer (or pedestal or wafer support) may improve the selectivity of
the metal film deposition by decreasing the amount of lateral film
deposition.
[0029] After the first surface and the second surface have been
pre-cleaned, a metal film 40 is deposited selectively on the first
surface 20 relative to the second surface 30, as shown in FIG. 3.
In some embodiments, substantially none of the metal film 40
deposits on the second surface 30. As used in this regard,
"substantially none" means that less than about 5%, 4%, 3%, 2% or
1% of the metal film is deposited on the second surface, as a total
weight of the metal film.
[0030] The selectivity of the metal film in greater than that of a
film deposited by the same conditions on a substrate that has not
been exposed to the pre-clean plasma. In some embodiments, the
metal film has a selectivity greater than or equal to about 40:1,
45:1, 50:1, 55:1, 60:1 or higher. In some embodiments, the
selectivity of the metal film is increased by 5.times., 6.times.,
7.times., 8.times., 9.times., 10.times. or more. For example, the
selectivity of the metal film on a pre-cleaned surface may be an
order of magnitude (10.times.) greater than the selectivity of the
metal film of a surface that has not been pre-cleaned, where the
surfaces have otherwise the same components.
[0031] In some embodiments, the first surface 20 is a metal surface
and the second surface 30 is a dielectric surface. In one or more
embodiments, the metal of the metal surface comprises one or more
of cobalt, copper, tungsten or ruthenium. The pre-clean plasma of
various embodiments removes or reduces the amount of oxides from
the surface of the metal surface
[0032] The metal film 40 deposited can be any suitable metal film.
In some embodiments, the metal film comprises one or more of
tungsten, cobalt or copper. In one or more embodiments, the metal
film 40 consists essentially of tungsten. As used in this regard,
the term "consists essentially of" means that the metal film is
greater than or equal to about 95 atomic percent of the specified
component. In some embodiments, the metal film is greater than
about 96, 97, 98 or 99 atomic percent of the specified
component.
[0033] In one or more embodiments, the metal film 40 comprises
tungsten. The tungsten can be deposited by a chemical vapor
deposition (CVD) process using a suitable tungsten precursor and
reactant or by thermal decomposition of a suitable tungsten
precursor. In some embodiments, the metal film 40 is deposited by
an atomic layer deposition (ALD) process in which at least a
portion of the substrate is sequentially exposed to a suitable
metal precursor and a reactant (e.g., a reducing agent).
[0034] Suitable tungsten precursors include, but are not limited
to, tungsten halides, organic tungsten and organometallic tungsten
complexes. In some embodiments, the tungsten precursor comprises
one or more of WF.sub.6, WCl.sub.6 or WCl.sub.5. In some
embodiments, the tungsten precursor comprises WF.sub.6 and the
reactant comprises H.sub.2.
[0035] Suitable co-reactants for a CVD or ALD process include, but
are not limited to, silane (SiH.sub.4), borane (B.sub.2H.sub.6),
hydrogen (H.sub.2), plasmas thereof or combinations thereof. In
some embodiments, the reactant comprises hydrogen. In some
embodiments, the reactant comprises silane. In some embodiments,
the reactant comprises borane. In some embodiments, the reactant
consists essentially of hydrogen. As used in this manner, the term
"consists essentially of" means that the reactive component in the
reactant gas (not including diluent, carrier or inert species) is
greater than or equal to about 95%, 98% or 99% of the stated
compound. In some embodiments, the reactant consists essentially of
silane. In some embodiments, the reactant consists essentially of
borane.
[0036] In some embodiments, the metal film 40 is deposited using a
combination of organometallic precursors and metal halide
precursors, having the same or different metals. For example, an
organometallic tungsten complex can be reacted with a tungsten
halide to form a tungsten film. The organometallic precursor and
metal halide precursor can form the metal film 40 by CVD or ALD,
with or without additional reactants (e.g., reducing agents).
[0037] In some embodiments, the deposition process occurs at a
temperature in the range of about 150.degree. C. to about
500.degree. C., or in the range of about 175.degree. C. to about
400.degree. C., or in the range of about 200.degree. C. to about
300.degree. C. In one or more embodiments, the deposition process
is a thermal process which occurs without plasma enhancement.
[0038] Depositing the metal film 40 on the substrate can include
moving the substrate from a pre-clean chamber to a deposition
chamber. In some embodiments, pre-clean chamber and the deposition
chamber are the same chamber. In some embodiments, the pre-clean
chamber and the deposition chamber are different chambers. In some
embodiments, the pre-clean chamber and the deposition chamber are
integrated so that moving the substrate from the pre-clean chamber
to the deposition chamber does not expose the substrate to air or
oxygen.
[0039] FIG. 4 shows a processing platform 100 in accordance with
one or more embodiment of the disclosure. The embodiment shown in
FIG. 4 is merely representative of one possible configuration and
should not be taken as limiting the scope of the disclosure. For
example, in some embodiments, the processing platform 100 has
different numbers of process chambers, buffer chambers and/or robot
configurations.
[0040] The processing platform 100 includes a central transfer
station 110 which has a plurality of sides 111, 112, 113, 114, 115,
116. The central transfer station 110 shown has a first side 111, a
second side 112, a third side 113, a fourth side 114, a fifth side
115 and a sixth side 116. Although six sides are shown, those
skilled in the art will understand that there can be any suitable
number of sides to the central transfer station 110 depending on,
for example, the overall configuration of the processing platform
100.
[0041] The transfer station 110 has a robot 117 positioned therein.
The robot 117 can be any suitable robot capable of moving a wafer
during processing. In some embodiments, the robot 117 has a first
arm 118 and a second arm 119. The first arm 118 and second arm 119
can be moved independently of the other arm. The first arm 118 and
second arm 119 can move in the x-y plane and/or along the z-axis.
In some embodiments, the robot 117 includes a third arm or a fourth
arm (not shown). Each of the arms can move independently of other
arms.
[0042] The processing platform 100 includes a pre-clean chamber 120
connected to a first side 111 of the central transfer station 110.
The pre-clean chamber 120 is configured to expose one or more
substrates to the pre-clean process described herein.
[0043] After the substrate has been cleaned in the pre-clean
chamber 120, the substrate can be moved to another chamber for
deposition. The processing platform 100 shown in FIG. 4 includes
two deposition chambers: a single wafer processing chamber 130 and
a batch processing chamber 140. Either of the single wafer
processing chamber 130 and the batch processing chamber 140 can be
a CVD and/or an ALD processing chamber.
[0044] In the illustrated embodiment, the batch processing chamber
140 is connected to a second side 112 of the central transfer
station 110 and the single wafer processing chamber 130 is
connected to a third side 113 of the central transfer station 110.
The batch processing chamber 140 can be configured to process x
wafers at a time for a batch time. In some embodiments, the batch
processing chamber 140 can be configured to process in the range of
about four (x=4) to about 12 (x=12) wafers at the same time. In
some embodiments, the batch processing chamber 140 is configured to
process six (x=6) wafers at the same time. As will be understood by
the skilled artisan, while the batch processing chamber 140 can
process multiple wafers between loading/unloading of an individual
wafer, each wafer may be subjected to different process conditions
at any given time. For example, a spatial atomic layer deposition
chamber exposes the wafers to different process conditions in
different processing regions within the processing chamber so that
as a wafer is moved through each of the regions, the process is
completed.
[0045] In the embodiment shown in FIG. 4, the processing platform
100 includes a second pre-clean chamber 150 connected to a fourth
side 114 of the central transfer station 110. The second pre-clean
chamber 150 can be the same as the pre-clean chamber 120 or
different.
[0046] The processing platform 100 can also include a first buffer
station 151 connected to a fifth side 115 of the central transfer
station 110 and/or a second buffer station 152 connected to a sixth
side 116 of the central transfer station 110. The first buffer
station 151 and second buffer station 152 can perform the same or
different functions. For example, the buffer stations may hold a
cassette of wafers which are processed and returned to the original
cassette, or the first buffer station 151 may hold unprocessed
wafers which are moved to the second buffer station 152 after
processing. In some embodiments, one or more of the buffer stations
are configured to pre-treat, pre-heat or clean the wafers before
and/or after processing.
[0047] The processing platform 100 may also include one or more
slit valves 160 between the central transfer station 110 and any of
the processing chambers. In the embodiment shown, there is a slit
valve 160 between each of the chambers and the central transfer
station 110. The slit valves 160 can open and close to isolate the
environment within the processing chamber from the environment
within the central transfer station 110. For example, if the
processing chamber will generate plasma during processing, it may
be helpful to close the slit valve for that processing chamber to
prevent stray plasma from damaging the robot in the transfer
station.
[0048] The processing platform 100 can be connected to a factory
interface 102 to allow wafers or cassettes of wafers to be loaded
into the processing platform 100. A robot 103 within the factory
interface 102 can be moved the wafers or cassettes into and out of
the buffer stations 151, 152. The wafers or cassettes can be moved
within the processing platform 100 by the robot 117 in the central
transfer station 110. In some embodiments, the factory interface
102 is a transfer station of another cluster tool.
[0049] The processing platform 100 can include a control system 195
connected to one or more of the robot 117, the pre-clean chamber
120, the pre-clean chamber 150, the single wafer processing chamber
130, the batch processing chamber 140, the buffer stations 151,
152, the slit valves 160, the factory interface 102 or the robot
103 inside the factory interface 102. The control system 195 can be
any suitable controller and may include a processor 196 coupled
with a memory 197 configured to enable the processing of one or
more substrates. For example, the processor 196 may be configured
with executable instructions stored in the memory 197 to enable
operations of the pre-clean chamber 120, 150, the single wafer
processing chamber 130, the batch processing chamber 140 and/or the
central transfer station 110 as described herein.
[0050] The control system 195 can be configured to move substrates
between and among the central transfer station 110, the pre-clean
chamber 120, 150, the batch processing chamber 140 and the single
wafer processing chamber 130. The control system 195 can move the
substrates using a first arm 118 or a second arm 119 of the robot
117. The control system 195 can be configured to control the slit
valves 160. It will be understood by those skilled in the art that
the control system 195 does not move the arms 118, 119 of the robot
117 directly; rather, the control system 195 causes the arms 118,
119 of the robot 117 to move the substrates using electrical
signals that control motors and/or actuators associated with the
various system components to achieve movement. Similarly, those
skilled in the art will understand that the control system 195 does
not pre-clean the substrate or deposit a film on the substrates;
rather, the control system 195 coordinates and provides electrical
signals to appropriate components to cause gases to flow, plasma to
be ignited, heating/cooling, etc., to achieve the cleaning and/or
deposition.
[0051] The control system 195 can be configured to control at least
one of composition, flow rate and/or pressure of the cleaning gas.
The control system 195 can be configured to control the ignition of
a plasma in the pre-clean chamber. The control system 195 can be
configured to control the temperature of the substrate in the
pre-clean chamber or the temperature of the pre-clean chamber by
controlling one or more heating/cooling elements in the pre-clean
chamber.
[0052] The control system 195 can be configured to control at least
one of the composition, flow rate and/or pressure of deposition
gases in the single wafer processing chamber 130 and/or the batch
processing chamber 140. The control system 195 can be configured to
control the temperature of a susceptor or substrate support or the
temperature of the processing chamber 130, 140.
[0053] In one or more embodiments, the processor 196 may be one of
any form of general-purpose computer processors that can be used in
an industrial setting for controlling various manufacturing
equipment used in semiconductor manufacturing. The memory 197 may
be in the form of a computer-readable medium and may be one or more
of readily available memory such as random access memory (RAM),
read only memory (ROM), floppy disk, hard disk, or any other form
of digital storage, local or remote. In one or more embodiments,
support circuits 198 are coupled to the processor 196 for
supporting the processor 196 in a conventional manner. These
support circuits 198 can include cache, power supplies, clock
circuits, input/output circuitry and subsystems, and the like.
[0054] In one or more embodiments, process routines for
pre-cleaning or film deposition may generally be stored in the
memory 197 as a software routine that, when executed by the
processor 196, causes the processing platform 100 to perform
processes disclosed herein. The software routine may also be stored
and/or executed by a second processor (not shown) that is remotely
located from the hardware being controlled by the processor 196.
The software routine, when executed by the processor 196 causes the
control system 195 to function as a specific purpose controller.
When the control system 195 includes a computer, the control system
195 functions as a special purpose computer for controlling the
processing platform 100 to perform the processes disclosed herein.
Some embodiments of the disclosure process a substrate with the
first surface and the second surface in a single processing chamber
where in a first portion of the chamber, the substrate surfaces are
exposed to the pre-clean plasma. The substrate may then be rotated
to a second portion of the processing chamber, and/or subsequent
portion of the processing chamber to deposit the metal film. To
separate each or any of the portions, or regions, of the processing
chamber, a gas curtain can be employed. The gas curtain provides
one or more of purge gas and vacuum ports between the processing
regions to prevent reactive gases from moving from one region to an
adjacent region. In some embodiments, the substrate is exposed to
more than one processing region at the same time, with one portion
of the substrate in a first region (e.g., for pre-clean exposure)
and another portion of the substrate at the same time being in a
separate region of the processing chamber.
[0055] According to one or more embodiments, the substrate is
subjected to processing prior to and/or after forming the layer.
This processing can be performed in the same chamber or in one or
more separate processing chambers. In some embodiments, the
substrate is moved from the first chamber to a separate, second
chamber for further processing. The substrate can be moved directly
from the first chamber to the separate processing chamber, or the
substrate can be moved from the first chamber to one or more
transfer chambers, and then moved to the separate processing
chamber. Accordingly, the processing apparatus may comprise
multiple chambers in communication with a transfer station. An
apparatus of this sort may be referred to as a "cluster tool" or
"clustered system", and the like.
[0056] Generally, a cluster tool is a modular system comprising
multiple chambers which perform various functions including
substrate center-finding and orientation, degassing, annealing,
deposition and/or etching. According to one or more embodiments, a
cluster tool includes at least a first chamber and a central
transfer chamber. The central transfer chamber may house a robot
that can shuttle substrates between and among processing chambers
and load lock chambers. The transfer chamber is typically
maintained at a vacuum condition and provides an intermediate stage
for shuttling substrates from one chamber to another and/or to a
load lock chamber positioned at a front end of the cluster tool.
Two well-known cluster tools which may be adapted for the present
disclosure are the Centura and the Endura both available from
Applied Materials, Inc., of Santa Clara, Calif. However, the exact
arrangement and combination of chambers may be altered for purposes
of performing specific steps of a process as described herein.
Other processing chambers which may be used include, but are not
limited to, cyclical layer deposition (CLD), atomic layer
deposition (ALD), chemical vapor deposition (CVD), physical vapor
deposition (PVD), etch, pre-clean, chemical clean, thermal
treatment such as RTP, plasma nitridation, degas, orientation,
hydroxylation and other substrate processes. By carrying out
processes in a chamber on a cluster tool, surface contamination of
the substrate with atmospheric impurities can be avoided without
oxidation prior to depositing a subsequent film.
[0057] According to one or more embodiments, the substrate is
continuously under vacuum or "load lock" conditions, and is not
exposed to ambient air when being moved from one chamber to the
next. The transfer chambers are thus under vacuum and are "pumped
down" under vacuum pressure. Inert gases may be present in the
processing chambers or the transfer chambers. In some embodiments,
an inert gas is used as a purge gas to remove some or all of the
reactants after forming the layer on the surface of the substrate.
According to one or more embodiments, a purge gas is injected at
the exit of the deposition chamber to prevent reactants from moving
from the deposition chamber to the transfer chamber and/or
additional processing chamber. Thus, the flow of inert gas forms a
curtain at the exit of the chamber.
[0058] During processing, the substrate can be heated or cooled.
Such heating or cooling can be accomplished by any suitable means
including, but not limited to, changing the temperature of the
substrate support (e.g., susceptor) and flowing heated or cooled
gases to the substrate surface. In some embodiments, the substrate
support includes a heater/cooler which can be controlled to change
the substrate temperature conductively. In one or more embodiments,
the gases (either reactive gases or inert gases) being employed are
heated or cooled to locally change the substrate temperature. In
some embodiments, a heater/cooler is positioned within the chamber
adjacent the substrate surface to convectively change the substrate
temperature.
[0059] The substrate can also be stationary or rotated during
processing. A rotating substrate can be rotated continuously or in
discreet steps. For example, a substrate may be rotated throughout
the entire process, or the substrate can be rotated by a small
amount between exposures to different reactive or purge gases.
Rotating the substrate during processing (either continuously or in
steps) may help produce a more uniform deposition or etch by
minimizing the effect of, for example, local variability in gas
flow geometries.
[0060] While the foregoing is directed to embodiments of the
present disclosure, other and further embodiments of the disclosure
may be devised without departing from the basic scope thereof, and
the scope thereof is determined by the claims that follow.
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