U.S. patent application number 13/039724 was filed with the patent office on 2011-06-23 for methods of thin film process.
This patent application is currently assigned to Applied Materials, Inc.. Invention is credited to Vikash Banthia, Mei Chang, Zhenbin Ge, Nitin K. Ingle, Chien-Teh Kao, Xinliang Lu, William H. McClintock, Jing Tang, Zheng Yuan, Yi Zheng.
Application Number | 20110151676 13/039724 |
Document ID | / |
Family ID | 39668463 |
Filed Date | 2011-06-23 |
United States Patent
Application |
20110151676 |
Kind Code |
A1 |
Ingle; Nitin K. ; et
al. |
June 23, 2011 |
METHODS OF THIN FILM PROCESS
Abstract
A method for forming a semiconductor structure includes forming
a plurality of features across a surface of a substrate, with at
least one space being between two adjacent features. A first
dielectric layer is formed on the features and within the at least
one space. A portion of the first dielectric layer interacts with a
reactant derived from a first precursor and a second precursor to
form a first solid product. The first solid product is decomposed
to substantially remove the portion of the first dielectric layer.
A second dielectric layer is formed to substantially fill the at
least one space.
Inventors: |
Ingle; Nitin K.; (San Jose,
CA) ; Tang; Jing; (Santa Clara, CA) ; Zheng;
Yi; (San Jose, CA) ; Yuan; Zheng; (Fremont,
CA) ; Ge; Zhenbin; (San Jose, CA) ; Lu;
Xinliang; (Fremont, CA) ; Kao; Chien-Teh;
(Sunnyvale, CA) ; Banthia; Vikash; (Mountain View,
CA) ; McClintock; William H.; (US) ; Chang;
Mei; (Saratoga, CA) |
Assignee: |
Applied Materials, Inc.
Santa Clara
CA
|
Family ID: |
39668463 |
Appl. No.: |
13/039724 |
Filed: |
March 3, 2011 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11947674 |
Nov 29, 2007 |
7939422 |
|
|
13039724 |
|
|
|
|
60869066 |
Dec 7, 2006 |
|
|
|
Current U.S.
Class: |
438/763 ;
257/E21.24; 438/703; 438/761 |
Current CPC
Class: |
H01L 21/31116 20130101;
H01L 21/67253 20130101; H01L 21/3105 20130101; H01L 21/76232
20130101; H01L 21/02164 20130101; H01L 21/0217 20130101 |
Class at
Publication: |
438/763 ;
438/703; 438/761; 257/E21.24 |
International
Class: |
H01L 21/31 20060101
H01L021/31 |
Claims
1. A method of fabricating a semiconductor structure, the method
comprising: providing a substrate having a least one trench between
two or more adjacent features; depositing a first layer comprising
silicon oxide within at least a portion of the trench; reacting at
least a portion of the first layer with reactive species from a
reactant gas mixture comprising a fluorine-containing gas and a
reducing gas, wherein the reaction forms a solid product comprising
materials from the first layer and the reactive species;
sublimating the solid product from the substrate to leave a
remaining portion of the first layer; and depositing a second layer
comprising a dielectric material on at least a part of the
remaining portion of the first layer.
2. The method of claim 1, wherein semiconductor substrate comprises
a semiconductor wafer.
3. The method of claim 2, wherein the semiconductor substrate
comprises a plurality of semiconductor wafers.
4. The method of claim 1, wherein fluorine-containing gas comprises
hydrogen fluoride.
5. The method of claim 1, wherein the fluorine-containing gas
comprises nitrogen trifluoride.
6. The method of claim 1, wherein the reducing gas comprises
ammonia.
7. The method of claim 1, wherein the solid product comprises an
ammonia fluorosilicate.
8. The method of claim 7, wherein the solid product comprises
(NF.sub.4).sub.2SiF.sub.6.
9. The method of claim 1, wherein the second layer comprises a
dielectric material selected from the group consisting of silicon
oxide, silicon nitride, silicon oxynitride, a low-.kappa.
dielectric material, and an ultra low-.kappa. dielectric
material.
10. The method of claim 1, wherein the first layer is deposited by
a process selected from the group consisting of a spin-coating
process, a high aspect ratio process, an e-HARP process, an APCVD
process, a HTUSG process, an HDP-CVD process, an PECVD process, a
furnace deposited oxide process, and an atomic layer deposition
process.
11. The method of claim 1, wherein the second layer is deposited by
a process selected from the group consisting of a spin-coating
process, a high aspect ratio process, an e-HARP process, an APCVD
process, a HTUSG process, an HDP-CVD process, an PECVD process, a
furnace deposited oxide process, and an atomic layer deposition
process.
12. A method of fabricating a semiconductor structure, the method
comprising: providing one or more wafer substrates each having at
least one trench between two or more adjacent features; depositing
a silicon oxide layer within at least a portion of the trench;
etching at least a portion of the silicon oxide layer by
sublimating an ammonia fluorosilicate solid product that is formed
from the reaction of the silicon oxide with a reactive species
generated from a gas mixture comprising hydrogen fluoride and
ammonia; and depositing a dielectric layer on a remaining portion
of the silicon oxide layer within the trench.
13. The method of claim 12, wherein the silicon oxide layer is
deposited by a high aspect ratio process.
14. The method of claim 12, wherein the remaining portion of the
silicon oxide layer forms an angle between slanted sidewalls of the
silicon oxide remaining in the trench and the silicon oxide
remaining in the bottom of the trench of about 87.degree. or
less.
15. The method of claim 12, wherein the dielectric layer comprises
silicon oxide deposited by a high aspect ratio process.
16. A method of processing a semiconductor substrate, the method
comprising: depositing a first silicon oxide layer on the
semiconductor substrate, wherein the substrate has at least one
trench formed thereon; exposing the semiconductor substrate at a
first temperature to hydrogen fluoride and ammonia, wherein the
hydrogen fluoride and ammonia react with a portion of the silicon
oxide layer to form a solid product; adjusting the substrate to a
second temperature greater than the first temperature to remove the
solid product and leave a remaining portion of the first silicon
oxide layer; and depositing a second silicon oxide layer on the
remaining portion of the first silicon oxide layer, wherein the at
least a portion of the second silicon oxide layer is deposited in
the trench.
17. The method of claim 16, wherein the first silicon oxide layer
is deposited by a high aspect ratio process.
18. The method of claim 16, wherein the second silicon oxide layer
is deposited by a high aspect ratio process.
19. The method of claim 16, wherein the solid product comprises an
ammonia fluorosilicate.
20. The method of claim 16, wherein the semiconductor substrate
comprises a silicon substrate.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/947,674, filed Nov. 29, 2007, which claims
the benefit of U.S. Provisional Application No. 60/869,066, filed
Dec. 7, 2006. This application is also related to the U.S. patent
application filed on the same day as the present application having
Attorney Docket No. A11598/T76820, titled "Mult-step Dep-Etch-Dep
High Aspect Ratio Process for Dielectric Gapfills." The entire
contents of both application are herein incorporated by reference
for all purposes.
[0002] This application is related to co-assigned U.S. Provisional
Patent Application No. 60/803,499 to Lubomirsky et al, filed May
30, 2006, and titled "PROCESS CHAMBER FOR DIELECTRIC GAPFILL." This
application is related to co-assigned U.S. Pat. No. 6,387,207 to
Janakiraman et al., issued May 14, 2002, and titled "INTEGRATION OF
REMOTE PLASMA GENERATOR WITH SEMICONDUCTOR PROCESSING CHAMBER."
This application is related to and co-assigned U.S. Pat. No.
6,830,624 to Janakiraman et al., issued Dec. 14, 2004, and titled
"BLOCKER PLATE BY-PASS FOR REMOTE PLASMA CLEAN." This application
is also related to co-assigned U.S. Pat. No. 5,558,717 to Zhao et
al., and titled "CVD PROCESSING CHAMBER." The entire contents of
both related applications is hereby incorporated by reference for
all purposes.
BACKGROUND OF THE INVENTION
[0003] Semiconductor device geometries have dramatically decreased
in size since their introduction several decades ago. Modern
semiconductor fabrication equipment routinely produces devices with
250 nm, 180 nm, and 65 nm feature sizes, and new equipment is being
developed and implemented to make devices with even smaller
geometries. The smaller sizes, however, mean device elements have
to work closer together which can increase the chances of
electrical interference, including cross-talk and parasitic
capacitance.
[0004] To reduce the degree of electrical interference, dielectric
insulating materials are used to fill the gaps, trenches, and other
spaces between the device elements, metal lines, and other device
features. The aspect ratio of a gap is defined by the ratio of the
gap's height or depth to its width. These spaces are difficult to
fill using conventional CVD methods. A film's ability to completely
fill such gaps is referred to as the film's "gapfilling"
ability.
[0005] Silicon oxide is one type of insulation film that is
commonly used to fill the gaps in intermetal dielectric (IMD)
applications, premetal dielectric (PMD) applications and shallow
trench isolation (STI) applications among others. Such a silicon
oxide film is often referred to as a gapfill film or a gapfill
layer.
[0006] Some integrated circuit manufacturers have turned to the use
of high density plasma CVD (HDP-CVD) systems to deposit silicon
oxide gapfill layers. HDP-CVD systems form a plasma that is
approximately two orders of magnitude or greater than the density
of a standard, capacitively-coupled plasma CVD system. Examples of
HDP-CVD systems include inductively-coupled plasma systems and
electron cyclotron resonance (ECR) plasma systems, among others.
HDP-CVD systems generally operate at lower pressure ranges than low
density plasma systems. The low chamber pressure employed in
HDP-CVD systems provides active species having a long
mean-free-path and reduced angular distribution. These factors, in
combination with the plasma's density, contribute to a significant
number of constituents from the plasma reaching even the deepest
portions of closely spaced gaps, providing a film with improved
gapfill capabilities as compared to films deposited in a low
density plasma CVD system.
[0007] Another factor that allows films deposited by HDP-CVD
techniques to have improved gapfill characteristics as compared to
films deposited by other CVD techniques is the occurrence of
sputtering, promoted by the plasma's high density, simultaneous
with film deposition. The sputtering element of HDP deposition
slows deposition on certain features, such as the corners of raised
surfaces, thereby contributing to the increased gapfill ability of
IDP deposited films. Some HDP-CVD systems introduce argon or a
similar heavy inert gas to further promote the sputtering effect.
These HDP-CVD systems typically employ an electrode within the
substrate support pedestal that enables the creation of an electric
field to bias the plasma toward the substrate. The electric field
can be applied throughout the HDP deposition process to generate
sputtering and provide better gapfill characteristics for a given
film. One HDP-CVD process commonly used to deposit a silicon oxide
film forms a plasma from a process gas that includes silane
(SiH.sub.4), molecular oxygen (O.sub.2) and argon (Ar).
[0008] However, a limitation associated with sputtering is an
angular redistribution of sputtered material. For example, in an
STI gapfill, the sputtered SiO.sub.2 can be sputtered from above
the trench and deposit on the sides of the trench, causing excess
buildup, and limiting the opening through which bottom-up gapfill
is achieved. If there is too much re-deposition, the trench can
close off before the bottom is filled, leaving a buried void within
the trench.
BRIEF SUMMARY OF THE INVENTION
[0009] Accordingly to an exemplary embodiment, a method for forming
a semiconductor structure includes forming a plurality of features
across a surface of a substrate, with at least one space being
between two adjacent features. A first dielectric layer is formed
on the features and within the at least one space. A portion of the
first dielectric layer interacts with a reactant derived from a
first precursor and a second precursor to form a first solid
product. The first solid product is decomposed to substantially
remove the portion of the first dielectric layer. A second
dielectric layer is formed to substantially fill the at least one
space.
[0010] Accordingly to an exemplary embodiment, forming a plurality
of features comprises forming at least a plurality of trenches,
conductive lines, openings and transistor gates.
[0011] Accordingly to an exemplary embodiment, forming the first
dielectric layer includes forming a silicon oxide layer.
[0012] Accordingly to an exemplary embodiment, interacting the
portion of the first dielectric layer with a reactant includes
ionizing the first precursor and the second precursor; and
interacting the ionized first precursor and the ionized second
precursor with the portion of the first dielectric layer.
[0013] Accordingly to an exemplary embodiment, the first precursor
is ammonia (NH.sub.3) and the second precursor is nitrogen
trifluoride (NF.sub.3).
[0014] Accordingly to an exemplary embodiment, interacting the
portion of the first dielectric layer with a reactant includes
interacting the portion of the first dielectric layer with the
ionized first precursor and the second precursor.
[0015] Accordingly to an exemplary embodiment, the first precursor
is nitrogen trifluoride (NF.sub.3) and the second precursor is
hydrogen fluoride (HF) or ammonia (NH.sub.3).
[0016] Accordingly to an exemplary embodiment, interacting the
portion of the first dielectric layer with a reactant includes
interacting the portion of the first dielectric layer with the
first precursor and the second precursor.
[0017] Accordingly to an exemplary embodiment, the first precursor
is ammonia (NH.sub.3) and the second precursor is hydrogen fluoride
(HF).
[0018] Accordingly to an exemplary embodiment, forming the first
dielectric layer comprises forming a silicon nitride layer.
[0019] Accordingly to an exemplary embodiment, interacting the
portion of the first dielectric layer with a reactant includes
ionizing the first precursor and the second precursor; and
interacting the portion of the silicon nitride layer with the
ionized first precursor and the ionized second precursor.
[0020] Accordingly to an exemplary embodiment, the first precursor
is hydrogen (H.sub.2) and the second precursor is nitrogen
trifluoride (NF.sub.3).
[0021] Accordingly to an exemplary embodiment, decomposing the
first solid product includes thermally treating the first solid
product to substantially sublimate the first solid product.
[0022] Accordingly to an exemplary embodiment, the method further
includes forming a liner under the first dielectric layer, wherein
an etch selectivity of the first dielectric layer to the liner is
about 8:1 or more.
[0023] Accordingly to an exemplary embodiment, the method further
includes interacting a portion of the liner with a reactant derived
from a third precursor and a fourth precursor to generate a second
solid product; and decomposing the second solid product to remove
the portion of the liner.
[0024] Accordingly to an exemplary embodiment, the method further
includes interacting another portion of the first dielectric layer
with a reactant derived from a third precursor and a fourth
precursor to generate a second solid product; and decomposing the
second solid product to remove the another portion of the first
dielectric layer.
[0025] Accordingly to an exemplary embodiment, forming the first
dielectric layer on the features and within the at least one space
has a process pressure of about 600 torr or more.
[0026] Accordingly to an exemplary embodiment, decomposing the
first solid product forms an angle between slanted sidewalls of the
removed first dielectric layer and a bottom of the removed first
dielectric layer about 87.degree. or less.
[0027] Accordingly to an exemplary embodiment, a method for forming
a semiconductor structure includes forming a plurality of trenches
across a surface of a substrate. A first dielectric layer is formed
on and within the trenches. A portion of the first dielectric layer
interacts with a reactant derived from a first precursor and a
second precursor to form a first solid product. The first solid
product is thermally treated to substantially sublimate the first
solid product to substantially remove the portion of the first
dielectric layer. A second dielectric layer is formed to
substantially fill the spaces.
[0028] Accordingly to exemplary embodiments, the steps in the
above-described method may be repeated for one or more additional
cycles of etching and depositing dielectric layers. For example, a
portion of the second dielectric layer deposited at the end of the
above-described method may further interact with the reactant to
form a second solid product that is sublimated in a thermal
treatment to remove that portion of the second dielectric layer. A
third dielectric layer may be formed on the remaining (i.e.,
non-etched) portion of the second dielectric layer. Additional
etching and dielectric deposition cycles may be performed until a
final dielectric layer is deposited that substantially fills the
remaining spaces (e.g., a dielectric cap layer).
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] A further understanding of the nature and advantages of the
present invention may be realized by reference to the remaining
portions of the specification and the drawings wherein like
reference numerals are used throughout the several drawings to
refer to similar components. In some instances, a sublabel is
associated with a reference numeral and follows a hyphen to denote
one of multiple similar components. When reference is made to a
reference numeral without specification to an existing sublabel, it
is intended to refer to all such multiple similar components.
[0030] FIGS. 1A-1D are schematic drawings showing an exemplary
process method for forming an exemplary shallow trench isolation
structure.
[0031] FIG. 2 is a schematic drawing showing an exemplary flowchart
of forming an exemplary shallow trench isolation structure.
[0032] FIG. 3 is a schematic flowchart of an exemplary process for
forming an exemplary trench isolation structure.
[0033] FIG. 4 is a schematic flowchart of an exemplary process for
forming an exemplary trench isolation structure.
[0034] FIG. 5A shows a vertical cross-sectional view of an
exemplary thin film deposition system.
[0035] FIG. 5B is a simplified diagram of an exemplary system
monitor/controller component of a thin film deposition system.
[0036] FIG. 6 is a schematic cross-sectional view of an exemplary
etch system.
DETAILED DESCRIPTION OF THE INVENTION
[0037] Systems and methods are described for forming at least one
dielectric layer over at least one feature, e.g., transistor gate,
formed across a surface of a substrate. A portion of the dielectric
layer interacts with a reactant derived from a first precursor and
a second precursor to form a solid product. The solid product can
be decomposed so as to substantially remove the portion of the
dielectric layer. Another dielectric layer then may be formed over
the etched dielectric layer, such that the aspect ratio gaps and/or
trenches may be filled with dielectric materials substantially
without gaps or seams.
Exemplary Processes
[0038] FIGS. 1A-1D are schematic drawings showing an exemplary
process method for forming an exemplary shallow trench isolation
structure. FIG. 2 is a schematic drawing showing an exemplary
flowchart of forming an exemplary shallow trench isolation
structure.
[0039] Referring to FIG. 1A, at least one feature, such as trenches
115, is formed across a surface of a substrate 100. The trenches
115 can be, for example, transistors, transistor gates, trenches,
openings, gaps, conductive lines or other feature that has an
aspect ratio of about 5:1 or more. In some embodiments, the
trenches 115 can be trenches. The trenches 115 can be formed across
the substrate 100. The substrate 100 may be a silicon substrate, a
III-V compound substrate, a silicon/germanium (SiGe) substrate, an
epi-substrate, a silicon-on-insulator (SOI) substrate, a display
substrate such as a liquid crystal display (LCD), a plasma display,
an electro luminescence (EL) lamp display, or a light emitting
diode (LED) substrate, for example. In some embodiments, the
substrate 100 may be a semiconductor wafer (e.g., a 200 mm, 300 mm,
400 mm, etc. silicon wafer).
[0040] Referring to FIG. 2, an exemplary process 200 for forming an
shallow trench isolation structure can include steps 210-250. Step
210 can form a plurality of trenches 115 across a surface of the
substrate 100.
[0041] Referring again to FIG. 1A, at least one pad dielectric
layer 105, such as pad oxide, can be formed over the substrate 100.
In some embodiments, at least one pad dielectric layer 110, such as
pad nitride, can be formed over the pad oxide 105. The pad
dielectric layers 105 and 110 can be formed, for example, by a
chemical vapor deposition (CVD) process, a thermal process and/or
other process that can desirably form a dielectric film layer. In
some embodiments, the trenches 115 can be formed by an etch process
which removes portions of the pad dielectric layers 105, 110 and
the substrate 100. In some embodiments, the pad dielectric layer
105 is nitride and the pad dielectric layer 110 is oxide. In some
embodiments, the pad dielectric layers 105 and 110 can be different
dielectric materials which have a desired etch selectivity.
[0042] Referring to FIGS. 1B and 2, step 220 can form at least one
dielectric layer, such as dielectric layer 120, over the trenches
115. The dielectric layer 120 can reduce the dimensions of the
trenches 115 to those of trenches 115a. The dielectric layer 120
can include at least one of a silicon oxide layer, a silicon
nitride layer, silicon oxynitride layer, a silicon oxycarbide layer
and other dielectric layer. In some embodiments, the dielectric
layer 120 can be thermal CVD oxide, such as high aspect ratio
process (HARP) oxide, eHARP oxide, atmosphere pressure CVD (APCVD)
oxide, or high temperature undoped silicate glass (HTUSG); high
density plasma (HDP) oxide; plasma-enhanced CVD (PECVD) oxide;
furnace deposited oxide, such as high temperature oxide, medium
temperature oxide or low temperature oxide; atomic layer deposition
(ALD) oxide, and other oxide. In some embodiments, the dielectric
layer 120 can be, for example, PECVD nitride, furnace deposited
nitride, HDP nitride, thermal CVD nitride, ALD nitride, and other
nitride. In some embodiments, the dielectric layer 120 may be
referred to as a high aspect ratio process (HARP) liner. In some
embodiments, the step 220 may have a process pressure of about 600
torrs or more.
[0043] In some embodiments, the dielectric layer 120 may be formed
from a silicon-containing precursor such as silane (SiH.sub.4),
dichlorosilane (SiH.sub.2Cl.sub.2), tricholorosilane (SiHCl.sub.3),
and silicontetrachloride (SiCl.sub.4) and a nitrogen-containing
precursor, such as nitrogen (N.sub.2) and ammonia (NH.sub.3). In
some embodiments, the dielectric layer 125 may be formed from a
silicon-containing precursor such as alkoxy disilanes, alkoxy-alkyl
disilanes, alkoxy-acetoxy disilanes and polysilanes; and a
nitrogen-containing precursor such as nitrogen and ammonia. For
example, the alkoxy disilanes may include Si.sub.2(EtO).sub.6
ethoxy disilanes, Si.sub.2(MeO).sub.6 methoxy disilanes, and
Si.sub.6(MeO).sub.12 methoxy cyclohexylsilanes, where Et denotes
ethyl group (C.sub.2H.sub.6) and Me denotes methyl group
(CH.sub.3). In some embodiments, the alkoxy-alkyl disilanes may
include Si.sub.2(EtO).sub.4(Me).sub.2 tetraethoxy-dimethyl
disilanes, Si.sub.2(EtO).sub.4(Et).sub.2 tetraethoxy-diethyl
disilanes, Si.sub.2(EtO).sub.2(Me).sub.4 diethoxy-tetramethyl
disilanes, Si.sub.2(MeO).sub.4(Me).sub.2 tetramethoxy-dimethyl
disilanes, and Si.sub.4O.sub.2(Me).sub.8 methyl
cyclohexylsiloxanes, Si.sub.6(MeO).sub.6(Me).sub.6 methoxy-methyl
cyclohexylsilanes, Si.sub.4O.sub.2(H.sub.2).sub.4
hydro-cyclohexylsiloxanes. In some embodiments, the alkoxy-acetoxy
disilanes may include Si.sub.2(AcO).sub.6 acetoxy disilanes,
Si.sub.2(Me).sub.4(AcO).sub.2 tetramethyl-diacetoxy disilanes, and
Si.sub.2(Me).sub.2(AcO).sub.4 dimethyl-tetracetoxy disilanes, where
Ac denotes acetyl group. In some embodiments, the polysilanes may
include cyclopentylsilanes or other substitutes.
[0044] In some embodiments, the dielectric layer 120 can be formed
over the pad dielectric layer 110, such that the trenches 115a may
have a top gap smaller than the middle and/or bottom gap of the
trenches 115a.
[0045] Referring to FIG. 1C, an etch process 130 can remove a
portion of the dielectric layer 120, such that the etched
dielectric layer 120a can have tapered sidewalls along the trenches
115b. In some embodiments, the etch process 130 can include steps
230, and 240 shown in FIG. 2. Step 230 may interact a portion of
the dielectric layer 120 with a reactant to form a solid product.
Step 240 can decompose the solid product to remove the interacted
portion of the dielectric layer 120, resulting the dielectric layer
120a. Following are exemplary embodiments of the etch process
130.
Exemplary Embodiment 1
[0046] In some embodiments, the dielectric layer 120 can be a
silicon oxide layer. A first precursor can be, for example,
hydrogen (H.sub.2), ammonia (NH.sub.3), hydrazine (N.sub.2H.sub.4),
hydrazoic acid (HN.sub.3), other hydrogen-containing precursor and
various combinations thereof. A second precursor can be, for
example, nitrogen trifluoride (NF.sub.3), silicon tetrafluorid
(SiF.sub.4), tetrafluoromethane (CF.sub.4), fluoromethane
(CH.sub.3F), difluoromethane (CH.sub.2F.sub.2), trifluoromethane
(CHF.sub.3), octafluoropropane (C.sub.3F.sub.8), hexafluoroethane
(C.sub.2F.sub.6), other fluorine-containing precursor or various
combinations thereof. In some embodiments, the first precursor such
as ammonia (NH.sub.3) and the second precursor such as nitrogen
trifluoride (NF.sub.3) can be ionized as a plasma. In some
embodiments, the ionization process can be performed within the
chamber that deposits the dielectric layer 120. In some
embodiments, the ionization process can be occurred externally and
then introduced into the chamber that deposits the dielectric layer
120. In some embodiments, the etch process 130 can be performed
within an etch chamber different from the deposition chamber. In
some embodiments, the etch process 130 may form an angle between
slanted sidewalls of the trenches 115b and a bottom of the trenches
115b about 87.degree. or less.
[0047] In some embodiments, NH.sub.3 may have a flow rate between
about 10 standard cubic centimeter per minute (sccm) and about
1,000 sccm. In some embodiments, NH.sub.3 may have a flow rate of
about 100 sccm. NF.sub.3 can have a flow rate between about 10 sccm
and about 1,000 sccm. In some embodiments, NF.sub.3 may have a flow
rate of about 100 sccm. The process temperature can be between
about 0.degree. C. and about 80.degree. C. In some embodiment, the
process temperature can be about 30.degree. C. The process pressure
can be between about 1 millitorr (mTorr) and about 1 atm. In some
embodiments, the process pressure can be 3 Tons. The plasma power
can be between about 10 Watts and about 2,000 Watts. In some
embodiments, the plasma power can be about 45 Watts. The
interaction of plasma of NH.sub.3 and NF.sub.3 can be represented
by the formula described below:
NH.sub.3(g)+NF.sub.3(g).fwdarw.NH.sub.4F.sub.(s) and/or
NH.sub.4F.sub.y.HF.sub.(s)
[0048] The reactant, NH.sub.4F.sub.(s) and/or
NH.sub.4F.sub.y.HF.sub.(s), then can be introduced to interact with
a portion of the silicon oxide layer. The reactant,
NH.sub.4F.sub.(s) and/or NH.sub.4F.sub.y.HF.sub.(s), may interact
with silicon oxide to form a solid product, e.g.,
(NF.sub.4).sub.2SiF.sub.6. In some embodiments, the substrate 100
is disposed over a pedestal having a temperature between about
-100.degree. C. and about 1,000.degree. C. (e.g., about -50.degree.
C. to about 200.degree. C.). In other embodiments, the pedestal may
have a temperature of about 30.degree. C. The temperature of the
pedestal may desirably enhance the interaction of the plasma and
silicon nitride. The interaction of the silicon oxide and the
reactant, NH.sub.4F.sub.(s) and/or NH.sub.4F.sub.y.HF.sub.(s), can
be described as the following formula:
NH.sub.4F.sub.(s) and/or
NH.sub.4F.sub.y.HF.sub.(s)+SiO.sub.2(s).fwdarw.(NF.sub.4).sub.2SiF.sub.6(-
s)+H.sub.2O
[0049] Referring again to FIG. 2, step 240 can decompose the solid
product, (NF.sub.4).sub.2SiF.sub.6. In some embodiments, step 240
can include thermally treating the solid product to substantially
sublimate the solid product (NF.sub.4).sub.2SiF.sub.6. In some
embodiments, the thermal process may be carried out by approaching
the solid product (NF.sub.4).sub.2SiF.sub.6 to a showerhead, which
may be operative to provide a process temperature between about
-100.degree. C. and about 1,000.degree. C. (e.g., about -50.degree.
C. to about 200.degree. C.). In an embodiment, the process
temperature is about 180.degree. C. In other embodiments, the
thermal process may be carried out by, for example, an oven, a
furnace, a rapid thermal anneal (RTA) apparatus, or other thermal
apparatus. The decomposition and/or sublimation of the solid
product (NF.sub.4).sub.2SiF.sub.6 may be described as the following
formula:
(NF.sub.4).sub.2SiF.sub.6(s).fwdarw.SiF.sub.4(g)+NH.sub.3(g)+HF.sub.(g)
[0050] Additional embodiments of a method to remove the solid
product may include the steps of rinsing the product containing
substrate with an aqueous solution (e.g., purified water) in lieu
of sublimating the product with a thermal treatment. The substrate
may also be rinsed with a polar solvent such as ethanol or glycol
in lieu of (or in addition to) the aqueous solution rinse.
Exemplary Embodiment 2
[0051] In some embodiments, the dielectric layer 120 can be a
silicon oxide layer. A first precursor can be, for example,
hydrogen (H.sub.2), ammonia (NH.sub.3), hydrazine (N.sub.2H.sub.4),
hydrazoic acid (HN.sub.3), other hydrogen-containing precursor and
various combinations thereof. A second precursor can be, for
example, hydrogen fluoride (HF), nitrogen trifluoride (NF.sub.3),
silicon tetrafluorid (SiF.sub.4), tetrafluoromethane (CF.sub.4),
fluoromethane (CH.sub.3F), difluoromethane (CH.sub.2F.sub.2),
trifluoromethane (CHF.sub.3), octafluoropropane (C.sub.3F.sub.8),
hexafluoroethane (C.sub.2F.sub.6), other fluorine-containing
precursor or various combinations thereof. In some embodiments, the
first precursor such as ammonia (NH.sub.3) and the second precursor
such as hydrogen fluoride (HF) can be used to interact with the
dielectric layer 120. In some embodiments, NH.sub.3 and HF can be
introduced within the chamber that deposits the dielectric layer
120. In some embodiments, NH.sub.3 and HF can be introduced within
an etch chamber different from the deposition chamber so as to
interact with the dielectric layer 120.
[0052] In some embodiments, NH.sub.3 may have a flow rate between
about 10 standard cubic centimeter per minute (sccm) and about
1,000 sccm. In some embodiments, NH.sub.3 may have a flow rate of
about 100 sccm. HF can have a flow rate between about 10 sccm and
about 2,000 sccm. In some embodiments, HF may have a flow rate of
about 200 sccm. The process temperature can be between about
0.degree. C. and about 80.degree. C. In some embodiment, the
process temperature can be about 30.degree. C. The process pressure
can be between about 1 millitorr (mTorr) and about 1 atm. In some
embodiments, the process pressure can be 3 Tons. The interaction of
NH.sub.3 and HF may be represented as the formula described
below:
NH.sub.3(g)+HF.sub.(g).fwdarw.NH.sub.4F.sub.(s) and/or
NH.sub.4F.sub.y.HF.sub.(s)
[0053] In some embodiments, NH.sub.3 and HF can be introduced into
the chamber for interacting with a portion of the silicon oxide
layer. NH.sub.3 and HF may interact with silicon oxide to form a
solid product, e.g., (NF.sub.4).sub.2SiF.sub.6(s). In some
embodiments, the substrate 100 is disposed over a pedestal having a
temperature between about -100.degree. C. and about 1,000.degree.
C. (e.g., about -50.degree. C. to about 200.degree. C.). In other
embodiments, the pedestal may have a temperature of about
30.degree. C. The temperature of the pedestal may desirably enhance
the interaction of the plasma and silicon nitride. The interaction
of the silicon oxide and the plasma can be described as the
following formula:
NH.sub.4F.sub.(s) and/or
NH.sub.4F.sub.y.HF.sub.(s)+SiO.sub.2(s).fwdarw.(NF.sub.4).sub.2SiF.sub.6(-
s)+H.sub.2O
[0054] Referring again to FIG. 2, step 240 can decompose the solid
product, (NF.sub.4).sub.2SiF.sub.6. In some embodiments, step 240
can include thermally treating the solid product to substantially
sublimate the solid product (NF.sub.4).sub.2SiF.sub.6. In some
embodiments, the thermal process may be carried out by approaching
the solid product (NF.sub.4).sub.2SiF.sub.6 to a showerhead, which
may be operative to provide a process temperature between about
-100.degree. C. and about 1,000.degree. C. (e.g., about -50.degree.
C. to about 200.degree. C.). In an embodiment, the process
temperature is about 180.degree. C. In other embodiments, the
thermal process may be carried out by, for example, an oven, a
furnace, a rapid thermal anneal (RTA) apparatus, or other thermal
apparatus. The decomposition and/or sublimation of the solid
product (NF.sub.4).sub.2SiF.sub.6 may be described as the following
formula:
(NF.sub.4).sub.2SiF.sub.6(s).fwdarw.SiF.sub.4(g)+NH.sub.3(g)+HF.sub.(g)
[0055] As noted above additional embodiments of the method to
remove the solid product may include the step of rinsing the
product containing substrate with an aqueous solution (e.g.,
purified water) in lieu of (or in addition to) sublimating the
product with a thermal treatment. The substrate may also be rinsed
with a polar solvent such as ethanol or glycol in lieu of (or in
addition to) the aqueous solution rinse.
Exemplary Embodiment 3
[0056] In some embodiments, the dielectric layer 120 can be a
silicon nitride layer. A first precursor can be, for example,
hydrogen (H.sub.2), ammonia (NH.sub.3), hydrazine (N.sub.2H.sub.4),
hydrazoic acid (HN.sub.3), other hydrogen-containing precursor and
various combinations thereof. A second precursor can be, for
example, hydrogen fluoride (HF), nitrogen trifluoride (NF.sub.3),
silicon tetrafluorid (SiF.sub.4), tetrafluoromethane (CF.sub.4),
fluoromethane (CH.sub.3F), difluoromethane (CH.sub.2F.sub.2),
trifluoromethane (CHF.sub.3), octafluoropropane (C.sub.3F.sub.8),
hexafluoroethane (C.sub.2F.sub.6), other fluorine-containing
precursor or various combinations thereof. A first precursor such
as hydrogen (H.sub.2) and a second precursor such as nitrogen
trifluoride (NF.sub.3) can be ionized as a plasma. In some
embodiments, the ionization process can be occurred within the
chamber that deposits the dielectric layer 120. In some
embodiments, the ionization process can be occurred externally and
then introduced into the chamber that deposits the dielectric layer
120. In some embodiments, the etch process 130 can be performed
within an etch chamber different from the deposition chamber.
[0057] In some embodiments, NF.sub.3 may have a flow rate between
about 10 standard cubic centimeter per minute (sccm) and about
1,000 sccm. In some embodiments, NF.sub.3 may have a flow rate of
about 100 sccm. H.sub.2 can have a flow rate between about 10 sccm
and about 3,000 sccm. In some embodiments, H.sub.2 may have a flow
rate of about 600 sccm. The process temperature can be between
about 0.degree. C. and about 80.degree. C. In some embodiment, the
process temperature can be about 30.degree. C. The process pressure
can be between about 1 millitorr (mTorr) and about 1 atm. In some
embodiments, the process pressure can be 3 Torrs. The plasma power
can be between about 10 Watts and about 2,000 Watts. In some
embodiments, the plasma power can be about 45 Watts.
[0058] The plasma then may be introduced into the chamber for
etching portions of the silicon oxide layer. The remote-generated
plasmas may interact with silicon oxide to form a solid product,
e.g., (NF.sub.4).sub.2SiF.sub.6. In some embodiments, the substrate
100 is disposed over a pedestal having a temperature between about
-100.degree. C. and about 1,000.degree. C. (e.g., about -50.degree.
C. to about 200.degree. C.). In other embodiments, the pedestal may
have a temperature of about 30.degree. C. The temperature of the
pedestal may desirably enhance the interaction of the plasma and
silicon nitride. The interaction of the silicon oxide and the
plasma can be described as the following formula:
NF.sub.3(g)+H.sub.2(g)+Si.sub.3N.sub.4.fwdarw.(NF.sub.4).sub.2SiF.sub.6(-
s)
[0059] Referring again to FIG. 2, step 240 can decompose the solid
product, (NF.sub.4).sub.2SiF.sub.6. In some embodiments, step 240
can include thermally treating the solid product to substantially
sublimate the solid product (NF.sub.4).sub.2SiF.sub.6. In some
embodiments, the thermal process may be carried out by approaching
the solid product (NF.sub.4).sub.2SiF.sub.6 to a showerhead, which
may be operative to provide a process temperature between about
-50.degree. C. and about 1,000.degree. C. In an embodiment, the
process temperature is about 180.degree. C. In other embodiments,
the thermal process may be carried out by, for example, an oven, a
furnace, a rapid thermal anneal (RTA) apparatus, or other thermal
apparatus. The decomposition and/or sublimation of the solid
product (NF.sub.4).sub.2SiF.sub.6 may be described as the following
formula:
(NF.sub.4).sub.2SiF.sub.6(s).fwdarw.SiF.sub.4(g)+NH.sub.3(g)+HF.sub.(g)
[0060] As noted above additional embodiments of the method to
remove the solid product may include the step of rinsing the
product containing substrate with an aqueous solution (e.g.,
purified water) in lieu of (or in addition to) sublimating the
product with a thermal treatment. The substrate may also be rinsed
with a polar solvent such as ethanol or glycol in lieu of (or in
addition to) the aqueous solution rinse.
[0061] Referring again to FIG. 1C, the pinch-off and the negative
profile of the dielectric layer 120 may be substantially
eliminated. The etched dielectric layer 120a may have a desired
profile, such that a subsequent dielectric layer such as dielectric
layer 140 (shown in FIG. 1D) can be desirably formed within the
trenches 115b.
[0062] Referring to FIGS. 1D and 2, step 250 can form a dielectric
layer 140 over the etched dielectric layer 120a. The dielectric
layer 140 may be formed of, for example, oxide, nitride,
oxynitride, low-k dielectric material, ultra low-k dielectric
material, other dielectric material or various combinations
thereof. The dielectric layer 140 may be formed by, for example, a
CVD process, a spin-coating process, other method that is adapted
to form a dielectric layer or various combinations thereof. In some
embodiments, the dielectric layer 140 can be thermal CVD oxide,
such as high aspect ratio process (HARP) oxide, eHARP oxide,
atmosphere pressure CVD (APCVD) oxide, or high temperature undoped
silicate glass (HTUSG), high density plasma (HDP) oxide,
plasma-enhanced CVD (PECVD) oxide, furnace deposited oxide, such as
high temperature oxide, medium temperature oxide or low temperature
oxide, atomic layer deposition (ALD) oxide, and other oxide. In
some embodiments, the dielectric layer 140 can be, for example,
PECVD nitride, furnace deposited nitride, HDP nitride, thermal CVD
nitride, ALD nitride, and other nitride. In some embodiments, the
dielectric layer 140 may be referred to as a high aspect ratio
process (HARP) cap layer. Since the pinch-off and negative profile
of the dielectric layer 120 (shown in FIG. 1B) is substantially
removed, the dielectric layer 140 may be desirably filled within
the gap between the etched dielectric layer 120a.
[0063] In some embodiments, an etch-back process and/or chemical
mechanical planarization (CMP) process is performed to
substantially planarize the top surface of the dielectric layer
140.
[0064] FIG. 3 is a schematic flowchart of an exemplary process for
forming an exemplary trench isolation structure. In process 300,
steps 310, 320, 330, 340, and 350 are similar to steps 210, 220,
230, 240, and 250 described above in conjunction with FIG. 2,
respectively.
[0065] In FIG. 3, step 312 may form a liner before forming the
dielectric layer 120. In some embodiments, the liner can include at
least one of a silicon oxide layer, a silicon nitride layer, a
silicon oxynitride layer, a silicon oxycarbide layer and other
dielectric layer. In some embodiments, an etch process may have an
etch selectivity of the dielectric layer 120 to the liner about 8:1
or more.
[0066] In some embodiments, the liner is oxide and the dielectric
layer 120 is nitride. For embodiments using plasma reaction, the
etch selectivity of the dielectric layer 120 to the liner can be
modified by changing process temperatures, plasma powers, NF.sub.3
flow rates, NH.sub.3 flow rates and/or process pressure. For
embodiments without using plasma reaction, the etch selectivity of
the dielectric layer 120 to the liner can be modified by changing
process temperatures, NH.sub.3 flow rates, HF flow rates and/or
process pressure.
[0067] In some embodiments, the liner is nitride and the dielectric
layer 120 is oxide. For embodiments using plasma reaction, the etch
selectivity of the dielectric layer 120 to the liner can be
modified by changing process temperatures, plasma powers, NF.sub.3
flow rates, H.sub.2 flow rates and/or process pressure.
[0068] Referring again to FIG. 3, step 314 can interact the liner
with a reactant derived from a third precursor and a fourth
precursor to form a solid product. In some embodiments, step 314
can be similar to step 230 set forth above in conjunction with FIG.
2. Step 316 can decompose the solid product to remove a portion of
the liner. In some embodiments, step 316 can be similar to step 240
described above in conjunction with FIG. 2.
[0069] In some embodiments, steps 314, and 316 can remove a portion
of the liner, such that the etched liner may provide a desired
profile over which the dielectric layer 120 (shown in FIG. 1A) can
be formed. By using steps 314, and 316 to etch a portion of the
liner, the pinch-off and the negative profile of the dielectric
layer 120 may be desirably eliminated.
[0070] FIG. 4 is a schematic flowchart of an exemplary process for
forming an exemplary trench isolation structure. In process 400,
steps 410, 420, 430, 440, and 450 are similar to steps 210, 220,
230, 240, and 250 described above in conjunction with FIG. 2,
respectively.
[0071] In FIG. 4, step 442 can interact another portion of the
etched dielectric layer 120a with a reactant derived from a third
precursor and a fourth precursor to form a solid product. In some
embodiments, step 442 may be similar to step 230 described above in
conjunction with FIG. 2. Step 444 can decompose the solid product
to remove the interacting portion of the etched dielectric layer
120a. In some embodiments, step 444 may be similar to step 240
described above in conjunction with FIG. 2.
[0072] In some embodiments, steps 442, and 444 can remove a portion
of the etched dielectric layer 120a, such that the etched
dielectric layer 120a may provide a desired profile over which the
dielectric layer 140 (shown in FIG. 1A) can be formed. By using
steps 442, and 444 to etch a portion of the etched dielectric layer
120a, the pinch-off and the negative profile of the dielectric
layer 120 can be desirably eliminated. In some embodiments, steps
442, and 444 can be repeated for one or more times to achieve a
desired profile of the etched dielectric layer 120a.
[0073] It is noted that the present invention is not limited to the
embodiments described above in conjunction with FIGS. 1A-1D and
2-4. Other methods for desirably filling dielectric layers within
gaps or openings of semiconductor substrates can be modified based
on the exemplary embodiments set forth above. For example, steps
312-316 shown in FIG. 3 may be incorporated with steps 442-444
shown in FIG. 4 to desirably fill dielectric layers within gaps or
openings of semiconductor substrates.
Exemplary Film Deposition System
[0074] Deposition systems that may deposit a dielectric layer may
include high-density plasma chemical vapor deposition (HDP-CVD)
systems, plasma enhanced chemical vapor deposition (PECVD) systems,
sub-atmospheric chemical vapor deposition (SACVD) systems, and
thermal chemical vapor deposition systems, among other types of
systems. Specific examples of CVD systems that may implement
embodiments of the invention include the CENTURA ULTIMA.TM. HDP-CVD
chambers/systems, and PRODUCER.TM. PECVD chambers/systems such as
PRODUCER.TM. Celera.TM. PECVD, available from Applied Materials,
Inc. of Santa Clara, Calif.
[0075] Examples of substrate processing systems that can be used
with exemplary methods of the invention may include those shown and
described in co-assigned U.S. Provisional Patent App. No.
60/803,499 to Lubomirsky et al, filed May 30, 2006, and titled
"PROCESS CHAMBER FOR DIELECTRIC GAPFILL," the entire contents of
which is herein incorporated by reference for all purposes.
Additional exemplary systems may include those shown and described
in U.S. Pat. Nos. 6,387,207 and 6,830,624, which are also
incorporated herein by reference for all purposes.
[0076] Referring now to FIG. 5A, vertical cross-sectional views of
a CVD system 10 is shown that has a vacuum or processing chamber 15
that includes a chamber wall 15a and a chamber lid assembly 15b.
The CVD system 10 may contain a gas distribution manifold 11 for
dispersing process gases to a substrate (not shown) that can rest
on a heated pedestal 12 centered within the process chamber 15. Gas
distribution manifold 11 may be formed from an electrically
conducting material in order to serve as an electrode for forming a
capacitive plasma. During processing, the substrate (e.g. a
semiconductor wafer) can be positioned on a flat (or slightly
convex) surface 12a of the pedestal 12. The pedestal 12 can be
moved controllably between a lower loading/off-loading position
(depicted in FIG. 5A) and an upper processing position (indicated
by dashed line 14 in FIG. 5A), which is closely adjacent to the
manifold 11. A centerboard (not shown) may include sensors for
providing information on the position of the wafers.
[0077] Deposition and carrier gases can be introduced into the
chamber 15 through perforated holes of a conventional flat,
circular gas distribution faceplate 13a. In some embodiments,
deposition process gases can flow into the chamber through the
inlet manifold 11, through a conventional perforated blocker plate
and then through holes in gas distribution faceplate 13a.
[0078] Before reaching the manifold 11, deposition and carrier
gases can be input from gas sources through gas supply lines into a
mixing system where they can be combined and then sent to manifold
11. In some embodiments, the supply line for each process gas can
include (i) several safety shut-off valves (not shown) that can be
used to automatically or manually shut-off the flow of process gas
into the chamber, and (ii) mass flow controllers (also not shown)
that measure the flow of gas through the supply line. When toxic
gases are used in the process, the several safety shut-off valves
are positioned on each gas supply line in conventional
configurations.
[0079] The deposition process performed in the CVD system 10 can be
a thermal process and/or a plasma-enhanced process. In a
plasma-enhanced process, an RF power supply can apply electrical
power between the gas distribution faceplate 13a and the pedestal
12 so as to excite the process gas mixture to form a plasma within
the cylindrical region between the faceplate 13a and the pedestal
12. (This region will be referred to herein as the "reaction
region"). Constituents of the plasma react to deposit a desired
film on the surface of the semiconductor wafer supported on
pedestal 12. RF power supply can be a mixed frequency RF power
supply that typically supplies power at a high RF frequency (RF1)
of 13.56 MHz and at a low RF frequency (RF2) of 360 KHz to enhance
the decomposition of reactive species introduced into the vacuum
chamber 15. In a thermal process, the RF power supply 44 would not
be utilized, and the process gas mixture can thermally react to
deposit the desired films on the surface of the semiconductor wafer
supported on the pedestal 12, which is resistively heated to
provide thermal energy for the reaction.
[0080] During a plasma-enhanced deposition process, the plasma can
heat the entire process chamber 10, including the walls of the
chamber body 15a surrounding the exhaust passageway 23 and the
shut-off valve 24. When the plasma is not turned on or during a
thermal deposition process, a hot liquid is circulated through the
walls 15a of the process chamber 15 to maintain the chamber at an
elevated temperature. The passages in the remainder of the chamber
walls 15a are not shown. Fluids used to heat the chamber walls 15a
can include the typical fluid types, i.e., water-based ethylene
glycol or oil-based thermal transfer fluids. This heating (referred
to as heating by the "heat exchanger") can desirably reduce and/or
eliminate condensation of undesirable reactant products and improve
the elimination of volatile products of the process gases and other
contaminants that might contaminate the process if they were to
condense on the walls of cool vacuum passages and migrate back into
the processing chamber during periods of no gas flow.
[0081] The remainder of the gas mixture that is not deposited in a
layer, including reaction byproducts, is evacuated from the chamber
15 by a vacuum pump (not shown). In some embodiments, the gases can
be exhausted through an annular, slot-shaped orifice 16 surrounding
the reaction region and into an annular exhaust plenum 17. The
annular slot 16 and the plenum 17 can be defined by the gap between
the top of the chamber's cylindrical side wall 15a (including the
upper dielectric lining 19 on the wall) and the bottom of the
circular chamber lid 20. The 360.degree. circular symmetry and
uniformity of the slot orifice 16 and the plenum 17 can be
configured to achieve a uniform flow of process gases over the
wafer so as to deposit a uniform film on the wafer.
[0082] From the exhaust plenum 17, the gases may flow underneath a
lateral extension portion 21 of the exhaust plenum 17, past a
viewing port (not shown), through a downward-extending gas passage
23, past a vacuum shut-off valve 24 (whose body is integrated with
the lower chamber wall 15a), and into the exhaust outlet 25 that
connects to the external vacuum pump (not shown) through a foreline
(also not shown).
[0083] The wafer support platter of the pedestal 12 (preferably
aluminum, ceramic, or a combination thereof) can be resistively
heated using an embedded single-loop embedded heater element
configured to make two full turns in the form of parallel
concentric circles. An outer portion of the heater element can run
adjacent to a perimeter of the support platter, while an inner
portion runs on the path of a concentric circle having a smaller
radius. The wiring to the heater element can pass through the stem
of the pedestal 12.
[0084] Typically, any or all of the chamber lining, gas inlet
manifold faceplate, and various other reactor hardware can be made
out of material such as aluminum, anodized aluminum, or ceramic. An
example of such a CVD apparatus is described in co-assigned U.S.
Pat. No. 5,558,717 entitled "CVD Processing Chamber," issued to
Zhao et al, and hereby incorporated by reference in its
entirety.
[0085] A lift mechanism and motor 32 (FIG. 5A) can raise and/or
lower the heater pedestal assembly 12 and its wafer lift pins 12b
as wafers are transferred into and out of the body of the chamber
15 by a robot blade (not shown) through an insertion/removal
opening 26 in the side of the chamber 10. The motor 32 can raise
and/or lower pedestal 12 between a processing position 14 and a
lower, wafer-loading position. The motor, valves or flow
controllers connected to the supply lines, gas delivery system,
throttle valve, RF power supply, and chamber and substrate heating
systems can be controlled by a system controller over control
lines, of which only some are shown. Controller can rely on
feedback from optical sensors to determine the position of movable
mechanical assemblies such as the throttle valve and susceptor
which are moved by appropriate motors under the control of
controller.
[0086] In the exemplary embodiment, the system controller can
include a hard disk drive (memory), a floppy disk drive and a
processor. The processor may contain a single-board computer (SBC),
analog and digital input/output boards, interface boards and
stepper motor controller boards. Various parts of CVD system 10 can
conform to the Versa Modular European (VME) standard which defines
board, card cage, and connector dimensions and types. The VME
standard can define the bus structure as having a 16-bit data bus
and a 24-bit address bus.
[0087] System controller can control the activities of the CVD
machine. The system controller executes system can control
software, which is a computer program stored in a computer-readable
medium such as a memory. In some embodiments, the memory can be a
hard disk drive or other kinds of memory. The computer program can
include sets of instructions that dictate the timing, mixture of
gases, chamber pressure, chamber temperature, RF power levels,
susceptor position, and other parameters of a particular process.
Other computer programs stored on other memory devices including,
for example, a floppy disk or other another appropriate drive, may
also be used to operate controller.
[0088] A process for depositing a film on a substrate or a process
for cleaning the chamber 15 can be implemented using a computer
program product that is executed by the controller. The computer
program code can be written in any conventional computer readable
programming language: for example, 68000 assembly language, C, C++,
Pascal, Fortran or others. Suitable program code is entered into a
single file, or multiple files, using a conventional text editor,
and stored or embodied in a computer usable medium, such as a
memory system of the computer. If the entered code text is in a
high level language, the code is compiled, and the resultant
compiler code is then linked with an object code of precompiled
Microsoft Windows.RTM. library routines. To execute the linked,
compiled object code the system user invokes the object code,
causing the computer system to load the code in memory. The CPU
then reads and executes the code to perform the tasks identified in
the program.
[0089] The interface between a user and the controller 34 can be
via a CRT monitor 50a and light pen 50b, shown in FIG. 5B, which
can be a simplified diagram of the system monitor and CVD system 10
in a substrate processing system, which may include one or more
chambers. In some embodiments, two monitors 50a can be used, one
mounted in the clean room wall for the operators and the other
behind the wall for the service technicians. The monitors 50a can
simultaneously display the same information. In some embodiments,
only one light pen 50b may be enabled. A light sensor in the tip of
light pen 50b can detect light emitted by CRT display. To select a
particular screen or function, the operator can touch a designated
area of the display screen and pushes the button on the pen 50b.
The touched area can change its highlighted color, or a new menu or
screen is displayed, confirming communication between the light pen
and the display screen. Other devices, such as a keyboard, mouse,
or other pointing or communication device, may be used instead of
or in addition to light pen 50b to allow the user to communicate
with controller 34.
[0090] FIG. 5A shows a remote plasma generator 60 mounted on the
lid assembly 15b of the process chamber 15 including the gas
distribution faceplate 13a and the gas distribution manifold 11. A
mounting adaptor 64 can mount the remote plasma generator 60 on the
lid assembly 15b, as best seen in FIG. 5A. The adaptor 64 can be
made of metal. The adaptor 64 may include a hole 95, which is
coupled to a ceramic isolator 66. A mixing device 70 may be coupled
to the upstream side of the gas distribution manifold 11 (FIG. 5A).
The mixing device 70 can include a mixing insert 72 disposed inside
a slot of a mixing block for mixing process gases. The ceramic
isolator 66 can be placed between the mounting adaptor 64 and the
mixing device 70 (FIG. 5A). The ceramic isolator 66 may be made of
a ceramic material such as Al.sub.2O.sub.3 (99% purity),
Teflon.RTM., or the like. When installed, the mixing device 70 and
ceramic isolator 66 may form part of the lid assembly 15b. The
isolator 66 can isolate the metal adaptor 64 from the mixing device
70 and gas distribution manifold 11 to minimize the potential for a
secondary plasma to form in the lid assembly 15b as discussed in
more detail below. A three-way valve can control the flow of the
process gases to the process chamber 15 either directly or through
the remote plasma generator 60.
[0091] The remote plasma generator 60 can be desirably a compact,
self-contained unit that can be conveniently mounted on the lid
assembly 15b and be easily retrofitted onto existing chambers
without costly and time-consuming modifications. One suitable unit
can be the ASTRON.RTM. generator available from Applied Science and
Technology, Inc. of Woburn, Mass. The ASTRON.RTM. generator
utilizes a low-field toroidal plasma to dissociate a process gas.
In one example, the plasma dissociates a process gas including a
fluorine-containing gas such as NF.sub.3 and a carrier gas such as
argon to generate free fluorine which is used to clean film
deposits in the process chamber 15.
Exemplary Etch System
[0092] Etch systems that may implement an etch process may include,
for example, a SiConi.TM. Preclean chamber/system, available from
Applied Materials, Inc. of Santa Clara, Calif.
[0093] FIG. 6 is a schematic cross-sectional view of an exemplary
etch chamber. The etch chamber 600 may include a chamber wall 630.
The etch chamber 600 may include a plasma distribution apparatus
610 such as a tube, pipe and/or manifold for dispersing a process
plasma 615 to the substrate 100 that rests on a pedestal 620
centered within the process chamber. The etch chamber 600 may be
coupled to a plasma generator 605 through the plasma distribution
apparatus 610. The plasma generator 605 is configured to generate
the plasma 615. The substrate 100 may be moved controllably between
a lower position/upper position near to a showerhead 650 by pins
640. The substrate 100 may have the trenches 115 and the dielectric
layer 120 (shown in FIG. 1B) formed thereover.
[0094] In some embodiments, the plasma distribution apparatus 610
may introduce the plasmas 615 generated by, for example, steps 230,
330, 430, 314, and 442 described above in connection with FIGS.
2-4, into the processing chamber 600. In some embodiments, the
supply line for the etch plasmas 615 may include (i) several safety
shut-off valves (not shown) that can be used to automatically or
manually shut-off the flow of process plasmas into the chamber, and
(ii) mass flow controllers (not shown) that measure the flow of the
plasmas 615 through the supply line.
[0095] Referring again to FIG. 6, the chamber wall 630 may have a
temperature to substantially prevent condensations of etchants
and/or byproducts thereon. In some embodiments, the pedestal 620
may be operative to provide a desired temperature between about
-100.degree. C. and about 1,000.degree. C. (e.g., about -50.degree.
C. to about 200.degree. C.) to condense etchants on the surface of
the substrate 100, i.e., the dielectric layer 120 over the
substrate 100. The etchants then may desirably interact with the
dielectric layer 120 formed over the substrate 100 so as to
generate the solid product described above in conjunction with FIG.
2-4. After the generation of the byproduct, pins 640 may lift the
substrate 100 approaching the showerhead 650. The showerhead 650
may be operative to provide a process temperature between about
-50.degree. C. and about 1,000.degree. C. In some embodiments, the
showerhead 650 may perform steps 240, 340, 440, 316, and 444
described above in conjunction with FIGS. 2-4 to decompose and/or
sublimate the solid product to remove the portions of the
dielectric layer 120 and liner.
[0096] Referring again to FIG. 6, at least one pumping channel 660
may be configured within the etch chamber 600 to desirably remove
the byproducts and/or the decomposed gases. The pumping channel 660
may be coupled to, for example, a pump or motor, such that the
byproducts may be desirably removed. In some embodiments, the
pumping channel 660 may have at least one aperture (not shown)
through which the byproducts can be desirably removed.
[0097] In some embodiments, an RF power supply (not shown) may be
coupled to the plasma generator 605 to excite a process gas
including a fluorine-containing precursor and a hydrogen-containing
precursor to form the plasma 615. The RF power supply may be
operative to provide a RF power between about 5 watts and about
3,000 watts. The RF power supply may supply the power at a RF
frequency between about 100 kHz and about 64 MHz.
[0098] system controller (not shown) may controls all of the
activities of the etch system. The system controller executes
system control software, which is a computer program stored in a
computer-readable medium such as a memory. In some embodiments, the
memory is a hard disk drive, but the memory may also be other kinds
of memory. The computer program includes sets of instructions that
dictate the timing, mixture of gases, chamber pressure, chamber
temperature and other parameters of a particular process. Other
computer programs stored on other memory devices including, for
example, a floppy disk or other another appropriate drive, may also
be used to operate controller.
[0099] A process for etching portions of a film over a substrate
can be implemented using a computer program product that is
executed by the controller described above. The computer program
code can be written in any conventional computer readable
programming language: for example, 68000 assembly language, C, C++,
Pascal, Fortran or others. Suitable program code is entered into a
single file, or multiple files, using a conventional text editor,
and stored or embodied in a computer usable medium, such as a
memory system of the computer. If the entered code text is in a
high level language, the code is compiled, and the resultant
compiler code is then linked with an object code of precompiled
Microsoft Windows.RTM. library routines. To execute the linked,
compiled object code the system user invokes the object code,
causing the computer system to load the code in memory. The CPU
then reads and executes the code to perform the tasks identified in
the program.
[0100] Having described several embodiments, it will be recognized
by those of skill in the art that various modifications,
alternative constructions, and equivalents may be used without
departing from the spirit of the invention. Additionally, a number
of well known processes and elements have not been described in
order to avoid unnecessarily obscuring the present invention.
Accordingly, the above description should not be taken as limiting
the scope of the invention.
[0101] Where a range of values is provided, it is understood that
each intervening value, to the tenth of the unit of the lower limit
unless the context clearly dictates otherwise, between the upper
and lower limits of that range is also specifically disclosed. Each
smaller range between any stated value or intervening value in a
stated range and any other stated or intervening value in that
stated range is encompassed. The upper and lower limits of these
smaller ranges may independently be included or excluded in the
range, and each range where either, neither or both limits are
included in the smaller ranges is also encompassed within the
invention, subject to any specifically excluded limit in the stated
range. Where the stated range includes one or both of the limits,
ranges excluding either or both of those included limits are also
included.
[0102] As used herein and in the appended claims, the singular
forms "a", "an", and "the" include plural referents unless the
context clearly dictates otherwise. Thus, for example, reference to
"a method" includes a plurality of such methods and reference to
"the precursor" includes reference to one or more precursors and
equivalents thereof known to those skilled in the art, and so
forth.
[0103] Also, the words "comprise," "comprising," "include,"
"including," and "includes" when used in this specification and in
the following claims are intended to specify the presence of stated
features, integers, components, or steps, but they do not preclude
the presence or addition of one or more other features, integers,
components, steps, acts, or groups.
* * * * *