U.S. patent application number 15/609977 was filed with the patent office on 2017-12-07 for high pressure ammonia nitridation of tunnel oxide for 3dnand applications.
The applicant listed for this patent is Applied Materials, Inc.. Invention is credited to Christopher S. OLSEN.
Application Number | 20170349996 15/609977 |
Document ID | / |
Family ID | 60477859 |
Filed Date | 2017-12-07 |
United States Patent
Application |
20170349996 |
Kind Code |
A1 |
OLSEN; Christopher S. |
December 7, 2017 |
HIGH PRESSURE AMMONIA NITRIDATION OF TUNNEL OXIDE FOR 3DNAND
APPLICATIONS
Abstract
Embodiments disclosed herein generally related to system for
forming a semiconductor structure. The processing chamber includes
a chamber body, a substrate support device, a quartz envelope, one
or more heating devices, a gas injection assembly, and a pump
device. The chamber body defines an interior volume. The substrate
support device is configured to support one or more substrates
during processing. The quartz envelope is disposed in the
processing chamber. The quartz envelope is configured to house the
substrate support device. The heating devices are disposed about
the quartz envelope. The gas injection assembly is coupled to the
processing chamber. The gas injection assembly is configured to
provide an NH.sub.3 gas to the interior volume of the processing
chamber. The pump device is coupled to the processing chamber. The
pump device is configured to maintain the processing chamber at a
pressure of at least 10 atm.
Inventors: |
OLSEN; Christopher S.;
(Fremont, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Applied Materials, Inc. |
Santa Clara |
CA |
US |
|
|
Family ID: |
60477859 |
Appl. No.: |
15/609977 |
Filed: |
May 31, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62343919 |
Jun 1, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/02323 20130101;
H01L 21/76826 20130101; C23C 8/36 20130101; H01L 21/76831 20130101;
H01L 27/115 20130101; H01L 21/76814 20130101; H01L 21/76816
20130101; C23C 8/02 20130101; H01L 21/0234 20130101; H01L 21/3115
20130101 |
International
Class: |
C23C 8/36 20060101
C23C008/36; H01L 21/768 20060101 H01L021/768; C23C 8/02 20060101
C23C008/02; H01L 27/115 20060101 H01L027/115 |
Claims
1. A processing chamber, comprising: a chamber body defining an
interior volume; a substrate support device configured to support
one or more substrates during processing; a quartz envelope
disposed in the processing chamber, the quartz envelop configured
to house the substrate support device; one or more heating devices
disposed about the quartz envelope; a gas injection assembly
coupled to the processing chamber, the gas injection assembly
configured to provide an NH3 gas to the interior volume of the
processing chamber; and a pump device coupled to the processing
chamber, the pump device configured to maintain the processing
chamber at a pressure of at least 10 atm.
2. The processing chamber of claim 1, wherein the pump device is
configured to maintain the processing chamber at a pressure between
about 10 atm and 20 atm.
3. The processing chamber of claim 1, further comprising: a
temperature control device configured to control a temperature of
the chamber body.
4. The processing chamber of claim 3, wherein the temperature
control device is a cooling channel formed in the chamber body, the
cooling channel configured to flow a heating transfer fluid through
the chamber body.
5. The processing chamber of claim 1, further comprising: a single
chamber door located at an end of the processing chamber,
configured to provide ingress and egress for the substrate support
device.
6. The processing chamber of claim 1, wherein the gas injection
assembly supplies the NH3 gas to an interior volume of the quartz
envelope.
7. The processing chamber of claim 1, wherein the one or more
substrates include a silicon dioxide (SiO2) layer formed
thereon.
8. A system for processing a substrate, comprising: a transfer
chamber; and a plurality of processing chambers coupled to the
transfer chamber, wherein at least one of the plurality of
processing chambers comprises: a chamber body defining an interior
volume; a substrate support device configured to support one or
more substrates during processing; a quartz envelope disposed in
the processing chamber, the quartz envelop configured to house the
substrate support device; one or more heating devices disposed
about the quartz envelope; a gas injection assembly coupled to the
processing chamber, the gas injection assembly configured to
provide an NH.sub.3 gas to the interior volume of the processing
chamber; and a pump device coupled to the processing chamber, the
pump device configured to maintain the processing chamber at a
pressure of at least 10 atm.
9. The system of claim 8, wherein the pump device is configured to
maintain the processing chamber at a pressure between about 10 atm
and 20 atm.
10. The system of claim 8, wherein the at least one of the
processing chambers further comprises: a temperature control device
configured to control a temperature of the chamber body.
11. The system of claim 10, wherein the temperature control device
is a cooling channel formed in the chamber body, the cooling
channel configured to flow a heating transfer fluid through the
chamber body.
12. The system of claim 8, wherein the at least one of the
processing chambers further comprises: a single chamber door
located at an end of the processing chamber, configured to provide
ingress and egress for the substrate support device.
13. The system of claim 8, wherein the gas injection assembly
supplies the NH3 gas to an interior volume of the quartz
envelope.
14. The system of claim 8, wherein the one or more substrates
include a silicon dioxide (SiO2) layer formed thereon.
15. A method of forming a semiconductor structure, comprising:
forming an oxide layer on a surface of a substrate; forming a via
in the oxide layer, the via extending at least partially into the
oxide layer; exposing the oxide layer to NH.sub.3; and maintaining
a chamber pressure of at least 10 atm while exposing the oxide
layer to NH.sub.3.
16. The method of claim 15, wherein the chamber pressure is
maintained between about 10 atm and 20 atm.
17. The method of claim 15, wherein the chamber is maintained
between about 1000 degrees C.
18. The method of claim 15, wherein the NH.sub.3 is configured to
travel from a top of the via to a bottom of the via.
19. The method of claim 15, wherein the NH.sub.3 is provided to the
oxide layer at a flow rate between 1 sLm to 20 sLm.
20. The method of claim 15, wherein the oxide layer is formed from
SiO.sub.2.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from U.S. Provisional
Application Ser. No. 62/343,919, filed Jun. 1, 2016, which is
hereby incorporated by reference in its entirety.
BACKGROUND
Field
[0002] Embodiments disclosed herein generally related to system for
forming a semiconductor structure, and a method of doing the
same.
Description of the Related Art
[0003] As the structure size of integrated circuit (IC) devices is
scaled down to sub-quarter micron dimensions, electrical
resistance, and current densities have become an area for concern
and improvement. Multilevel interconnect technology provides the
conductive paths throughout an IC device, and are formed in high
aspect ratio features including contacts, plugs, vias, lines,
wires, and other features. A typical method for forming an
interconnect on a substrate includes depositing one or more layers,
etching at least one of the layer(s) to form one or more features,
depositing a barrier layer in the feature(s), and depositing one or
more layers to fill the feature. Typically, a feature (or via) is
formed in an oxide material disposed on a substrate.
[0004] Plasma nitridation has been used to nitride (i.e.,
incorporate nitrogen into) the oxide layer. This technique results
in high nitrogen concentration on a surface of the oxide layer. As
the demand for higher aspect ratios increase, it becomes
increasingly more difficult to nitride the oxide layer. This is due
to a combination of the average lifetime of the nitrogen compounds
used in conventional nitridation processes, and the depth of the
features in higher aspect ratios. Conventional processes are unable
to adequately nitride the entire feature formed in the oxide
layer.
[0005] Thus, an improved processing chamber and method for forming
a semiconductor structure are needed.
SUMMARY
[0006] Embodiments disclosed herein generally related to system for
forming a semiconductor structure. The processing chamber includes
a chamber body, a substrate support device, a quartz envelope, one
or more heating devices, a gas injection assembly, and a pump
device. The chamber body defines an interior volume. The substrate
support device is configured to support one or more substrates
during processing. The quartz envelope is disposed in the
processing chamber. The quartz envelope is configured to house the
substrate support device. The heating devices are disposed about
the quartz envelope. The gas injection assembly is coupled to the
processing chamber. The gas injection assembly is configured to
provide an NH3 gas to the interior volume of the processing
chamber. The pump device is coupled to the processing chamber. The
pump device is configured to maintain the processing chamber at a
pressure of at least 10 atm.
[0007] In another embodiment, a system for forming a semiconductor
structure is disclosed herein. The system includes a transfer
chamber and a plurality of processing chambers. The plurality of
processing chambers is coupled to the transfer chamber. At least
one of the plurality of processing chambers includes a chamber
body, a substrate support device, a quartz envelope, one or more
heating devices, a gas injection assembly, and a pump device. The
chamber body defines an interior volume. The substrate support
device is configured to support one or more substrates during
processing. The quartz envelope is disposed in the processing
chamber. The quartz envelope is configured to house the substrate
support device. The heating devices are disposed about the quartz
envelope. The gas injection assembly is coupled to the processing
chamber. The gas injection assembly is configured to provide an NH3
gas to the interior volume of the processing chamber. The pump
device is coupled to the processing chamber. The pump device is
configured to maintain the processing chamber at a pressure of at
least 10 atm.
[0008] In another embodiment, a method of forming a semiconductor
structure on a substrate is formed herein. An oxide layer is formed
on the surface of the substrate. A via is formed in the oxide
layer. The via extends at least partially into the oxide layer. The
oxide layer is exposed to NH3. The chamber pressure is maintained
at a pressure of at least 10 atm while the oxide layer is exposed
to NH3.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] 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.
[0010] FIG. 1 is a schematic view of an integrated tool 100 for
processing semiconductor substrates in which embodiments of the
disclosure may be practiced.
[0011] FIG. 2 is a cross-sectional view of a plasma nitridation
chamber, according to one embodiment.
[0012] FIG. 3 is a flow diagram that illustrates a method of
forming a semiconductor device, according to one embodiment.
[0013] FIGS. 4A-4C illustrate cross-sectional views of a substrate
at different stages of the method of FIG. 3.
[0014] For clarity, identical reference numerals have been used,
where applicable, to designate identical elements that are common
between figures. Additionally, elements of one embodiment may be
advantageously adapted for utilization in other embodiments
described herein.
DETAILED DESCRIPTION
[0015] FIG. 1 is a schematic view of an integrated tool 100 for
processing semiconductor substrates in which embodiments of the
disclosure may be practiced. Examples of suitable integrated tools
include the CENTURA.RTM. and ENDURA.RTM. integrated tools, all
available from Applied Materials, Inc. of Santa Clara, Calif. It is
contemplated that the methods described herein may be practiced in
other tools having the requisite process chambers coupled thereto,
including those from other manufacturers.
[0016] The integrated processing tool 100 includes a vacuum-tight
processing platform 101, a factory interface 104, and a system
controller 102. The platform 101 has a plurality of processing
chambers 114A-114D and loadlock chambers 106A-106B that are coupled
to a vacuum substrate transfer chamber 103. The factory interface
104 is coupled to the transfer chamber 103 by the loadlock chambers
106A-106B.
[0017] In one embodiment, the factory interface 104 includes at
least one docking station 107 and at least one factory interface
robot 138. The docking station 107 is configured to accept one or
more front opening unified pods (FOUPs). Four FOUPs 105A-105D are
shown in the embodiment of FIG. 1. The factory interface robot 138
is configured to transfer substrates in the factory interface 104
between the FOUPs 105A-105D and the loadlock chambers
106A-106B.
[0018] The loadlock chambers 106A-106B have a first port coupled to
the factory interface 104 and a second port coupled to the transfer
chamber 103. The loadlock chambers 106A-106B are coupled to a
pressure control system (not shown) which pumps down and vents the
chambers 106A-106B to facilitate passing the substrate between the
vacuum environment of the transfer chamber 103 and the
substantially ambient (e.g., atmospheric) environment of the
factory interface,
[0019] The transfer chamber 103 has a vacuum robot 113 disposed
therein. The vacuum robot 113 is capable of transferring substrates
121 between the loadlock chamber 106A-106B and the processing
chambers 114A-114D.
[0020] In one embodiment, the processing chambers coupled to the
transfer chamber 103 may be a chemical vapor deposition (CVD)
chamber 114D, a plasma nitridation chamber 114C, a rapid thermal
process (RTP) chamber 114B, or an atomic layer deposition (ALD)
chamber 114A. The particular chambers shown coupled to the transfer
chamber 103 are examples of chambers that may be coupled to the
transfer chamber 103. Alternatively, different processing chambers,
including at least one of ALD, CVD, metal organic chemical vapor
deposition (MOCVD), physical vapor deposition (PVD), plasma
nitridation, or RTP chambers may be interchangeably incorporated
into the integrated processing tool 100 in accordance with process
requirements.
[0021] The system controller 102 is coupled to the integrated
processing tool 100. The system controller 102 controls the
operation of the integrated processing tool 100 by direct control
of the processing chambers 114A-114D of the integrated processing
tool 100, or alternatively, by controlling the computers (or
controllers) associated with the processing chambers 114A-114D of
the integrated processing tool 100. In operation, the system
controller 102 enables data collection and feedback from the
respective chambers and system to optimize performance of the
integrated processing tool 100.
[0022] The system controller 102 generally includes a central
processing unit (CPU) 130, memory 136, and support circuit 132. The
CPU 130 may be one of any form of a general purpose computer
processor that can be used in an industrial setting. The support
circuits 132 are conventionally coupled to the CPU 130 and may
comprise cache, clock circuits, input/output subsystems, power
supplies, and the like. The software routines when executed by the
CPU 130 transform the CPU into a specific purpose computer
(controller) and enable processes, such as the method described in
conjunction with FIG. 3, to be performed on the integrated
processing tool 100. The software routines may also be stored
and/or executed by a second controller (not shown) that is located
remotely from the integrated processing tool 100.
[0023] FIG. 2 is a cross-sectional view of a plasma nitridation
chamber 114C according to one embodiment. The plasma nitridation
chamber 114C includes a chamber body 202 defining an interior
volume 204. The plasma nitridation chamber 114C further includes a
quartz envelope 206. The quartz envelope 206 is configured to house
a substrate support device 208. The substrate support device 208 is
configured to support one or more substrates 201 in the plasma
nitridation chamber 114C. In the embodiment shown in FIG. 2, the
substrate support device 208 is configured to support one or more
substrates 201 in a vertical orientation in the quartz envelope
206.
[0024] The plasma nitridation chamber 114C further includes a
plurality of heating elements 210. The plurality of heating
elements 210 is positioned about the quartz envelope 206. The
plurality of heating elements 210 is configured to heat the quartz
envelope 206 to a desired temperature. For example, the plurality
of heating elements 210 may heat the quartz envelope 206 to a
temperature between 600.degree. C. and 1,200.degree. C.
[0025] The plasma nitridation chamber 114C may further include a
gas injection assembly 212 coupled to a gas source 216, a pump
device 214, and an exhaust assembly 218. The gas injection assembly
212 is configured to provide a gas to the interior volume 204 of
the chamber 114C. In one embodiment, the gas source 216 is
configured to provide NH3 gas to the interior volume 204 and inside
the quartz envelope 206, such that the nitridation rate of the one
or more substrates 201 is increased. The NH.sub.3 gas may be
provided, in neat (i.e. 100%), concentrated (i.e. 50% up to 100%),
or dilute (i.e. <50%) form, at a flow rate of 1 sLm to 20 sLm,
for example 10 sLm. The pump device 214 is coupled to the
nitridation chamber 114C, in communication with the interior volume
204. The pump device 214 is configured to control a pressure of the
interior volume 204 of the chamber 114C. For example, the pump
device 214 is configured to maintain a pressure of between 10-20
atmospheres (atm) while the gas injection assembly 212 provides
NH.sub.3 gas to the interior volume 204. The exhaust assembly 218
may be disposed on an opposite side of the chamber 114C from the
gas injection assembly 212. The exhaust assembly 218 is configured
to remove the NH.sub.3 gas from the chamber 114C.
[0026] The plasma nitridation chamber 114C may further include a
temperature control device 220. The temperature control device 220
is configured to control a temperature of the chamber body 202 of
the chamber 114C during processing. In one embodiment, the
temperature control device may be in the form of thermal shield
plates coupled to the chamber body 202. In the embodiment
illustrated in FIG. 1, the temperature control device 220 is in the
form of a cooling channel 222 formed in the chamber body 202. The
cooling channel 222 is configured to flow a heat transfer fluid
through the chamber body 202, to control the temperature of the
chamber body 202 during processing.
[0027] FIG. 3 is a flow diagram that illustrates a method 300 of
forming a semiconductor device 400, according to one embodiment.
FIGS. 4A-4D illustrate cross-sectional views of a substrate 401 at
different stages of the method 300 of FIG. 3. FIG. 4A depicts the
substrate 401 without any layers deposited thereon. The method 300
begins at block 302. At block 302, an oxide layer 402 is formed on
the substrate 401. In one embodiment, the oxide layer 402 may be
formed from SiO.sub.2. The oxide layer 402 may be formed on the
substrate 401 in a process chamber such as one of the processing
chambers 114A-114D in FIG. 1. For example, the oxide layer 402 may
be formed in the RADIANCE.RTM. system, available from Applied
Materials, Inc. The oxide layer 402 may be deposited on the
substrate 401 through CVD, rapid thermal-CVD (RT-CVD), plasma
enhanced-CVD (PECVD), physical vapor deposition (PVD), ALD, or
combinations thereof. In one embodiment, the oxide layer 402 may
have a thickness between about 1.5 nm to about 3 nm.
[0028] At block 304, a via 404 is formed in the Oxide layer 402, as
shown in FIG. 4C. The via 404 may extend partially into the Oxide
layer 402, from a top surface 406 of the Oxide layer.
[0029] At block 306, the substrate 401 having the Oxide layer 402
deposited thereon, is transferred to a plasma nitridation chamber,
such as the plasma nitridation chamber 114C, to undergo a
nitridation process. During the nitridation process, the oxygen on
the surface of the oxide layer 402 is replaced by nitrogen. In one
embodiment, about 40% of the oxygen in the oxide layer 402 is
replaced with nitrogen. Conventionally, NH.sub.2 and NH have been
used for nitridation processes. Due to the higher electronegativity
of oxygen compared to nitrogen, highly reactive species are
typically used to displace oxygen in such processes. N*, NH.sub.2,
and NH have however proven to be too unstable to live long enough
to travel down the high aspect ratio features in the Oxide layer
and conformally nitride the feature. To penetrate to the bottom of
such features at concentrations that support conformal nitridation,
the nitriding species need to survive one or more wall contact
events without sticking, reacting, or extinguishing. Reduced
reactivity species, or species having lower sticking coefficient,
are needed. NH.sub.2 and NH may quickly relax back to N.sub.2 and
H.sub.2 when they react with the oxide, resulting in a short
residence time in the via 404. For example, the average lifetime of
NH.sub.2 and NH may be about 10 ms. Additionally, it is difficult
to lower reactivity and yet still have sufficient energy to nitride
the oxide. By substituting NH.sub.3 for NH and NH.sub.2, the
conformal nitridation process with a high temperature NH.sub.3 is
driven by the partial pressure of NH3, and enhances the nitridation
process. It has been found that while increases in processing
temperature and processing time increase the number of nitrogen
atoms in NH.sub.3 incrementally, the increase in pressure,
particularly the increase in partial pressure, of NH3 during
processing increases the number of nitrogen atoms at a greater
rate.
[0030] At block 306, the substrate is exposed to NH.sub.3, as shown
in FIG. 4D. The reaction of NH.sub.3 and SiO.sub.2 yields:
NH.sub.3*+SiO.sub.2.fwdarw.SiON+H.sub.2O
[0031] The temperature needed to drive the reaction forward is at
least 600.degree. C. In one embodiment, the temperature is about
1000.degree. C. The NH3 is provided to the substrate at a flow rate
of about 1 sLm to 20 sLm, for example 10 sLm. As noted above, the
NH3 may be provided in neat, concentrated, or dilute form. The
NH.sub.3 is configured to travel to a bottom 408 of the via
404.
[0032] At block 308, the processing chamber is maintained at a
pressure of at least 10 atm while the substrate is exposed to
NH.sub.3. In one embodiment, the pressure of the processing chamber
is maintained at a pressure between 10 atm and 20 atm.
[0033] While the foregoing is directed to specific embodiments,
other and further embodiments may be devised without departing from
the basic scope thereof, and the scope thereof is determined by the
claims that follow.
* * * * *