U.S. patent application number 16/691947 was filed with the patent office on 2020-03-26 for fully self-aligned via.
This patent application is currently assigned to Micromaterials LLC. The applicant listed for this patent is Regina Freed, Ho-yung David Hwang, Nitin K. Ingle, Abhijit Basu Mallick, Uday Mitra, Ying Zhang. Invention is credited to Regina Freed, Ho-yung David Hwang, Nitin K. Ingle, Abhijit Basu Mallick, Uday Mitra, Ying Zhang.
Application Number | 20200098633 16/691947 |
Document ID | / |
Family ID | 63671783 |
Filed Date | 2020-03-26 |
View All Diagrams
United States Patent
Application |
20200098633 |
Kind Code |
A1 |
Zhang; Ying ; et
al. |
March 26, 2020 |
FULLY SELF-ALIGNED VIA
Abstract
A first metallization layer comprising a set of first conductive
lines that extend along a first direction on a first insulating
layer on a substrate. A second insulating layer is on the first
insulating layer. A second metallization layer comprises a set of
second conductive lines on a third insulating layer and on the
second insulating layer above the first metallization layer. The
set of second conductive lines extend along a second direction that
crosses the first direction at an angle. A via between the first
metallization layer and the second metallization layer. The via is
self-aligned along the second direction to one of the first
conductive lines.
Inventors: |
Zhang; Ying; (Santa Clara,
CA) ; Mallick; Abhijit Basu; (Palo Alto, CA) ;
Freed; Regina; (Los Altos, CA) ; Ingle; Nitin K.;
(Santa Clara, CA) ; Mitra; Uday; (Cupertino,
CA) ; Hwang; Ho-yung David; (Cupertino, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Zhang; Ying
Mallick; Abhijit Basu
Freed; Regina
Ingle; Nitin K.
Mitra; Uday
Hwang; Ho-yung David |
Santa Clara
Palo Alto
Los Altos
Santa Clara
Cupertino
Cupertino |
CA
CA
CA
CA
CA
CA |
US
US
US
US
US
US |
|
|
Assignee: |
Micromaterials LLC
Wilmington
DE
|
Family ID: |
63671783 |
Appl. No.: |
16/691947 |
Filed: |
November 22, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16520546 |
Jul 24, 2019 |
10522404 |
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16691947 |
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16272059 |
Feb 11, 2019 |
10410921 |
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16520546 |
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15679458 |
Aug 17, 2017 |
10424507 |
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16272059 |
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62481301 |
Apr 4, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/76897 20130101;
H01L 23/53266 20130101; H01L 21/76811 20130101; H01L 21/76849
20130101; H01L 23/481 20130101; H01L 21/76834 20130101; H01L
23/5329 20130101; H01L 23/53252 20130101; H01L 23/528 20130101;
H01L 21/76805 20130101; H01L 23/53238 20130101; H01L 21/76801
20130101; H01L 21/76877 20130101 |
International
Class: |
H01L 21/768 20060101
H01L021/768; H01L 23/532 20060101 H01L023/532; H01L 23/528 20060101
H01L023/528; H01L 23/48 20060101 H01L023/48 |
Claims
1. An electronic device comprising: a first metallization layer
comprising a set of first conductive lines extending along a first
direction on a first insulating layer on a substrate; a second
insulating layer on the first insulating layer; a second
metallization layer comprising a set of second conductive lines on
the second insulating layer and a third insulating layer above the
first metallization layer, the set of second conductive lines
extending along a second direction that crosses the first direction
at an angle; and a via between the first metallization layer and
the second metallization layer, wherein the via is self-aligned
along the second direction to one of the first conductive
lines.
2. The electronic device of claim 1, wherein the via is
self-aligned along the first direction to one of the second
conductive lines.
3. The electronic device of claim 1, wherein the third insulating
layer is etch selective relative to the second insulating
layer.
4. The electronic device of claim 1, further comprising a liner on
the first conductive lines.
5. The electronic device of claim 1, wherein the via has a trench
portion that is a part of the one of the second conductive lines
and a via portion underneath the trench portion.
6. The electronic device of claim 1, wherein the third insulating
layer is deposited on the first conductive lines.
7. The electronic device of claim 1, wherein the via is formed in
the second insulating layer.
8. A method to provide a self-aligned via, comprising: recessing
first conductive lines on a first insulating layer on a substrate,
the first conductive lines extending along a first direction on the
first insulating layer; forming pillars on the recessed first
conductive lines; depositing a second insulating layer between the
pillars; removing the pillars to form trenches in the second
insulating layer; depositing a third insulating layer through the
trenches onto the recessed first conductive lines; and etching the
third insulating layer selectively relative to the second
insulating layer to form a via opening down to one of the first
conductive lines.
9. The method of claim 8, wherein the via opening is self-aligned
along the first direction and a second direction to the one of the
first conductive lines, the second direction crossing the first
direction at an angle.
10. The method of claim 8, further comprising selectively growing a
seed layer on the recessed first conductive lines, wherein the
pillars are formed on the seed layer.
11. The method of claim 8, further comprising forming a hard mask
layer on at least one of the second insulating layer and the third
insulating layer.
12. The method of claim 8, further comprising depositing a liner on
the recessed first conductive lines.
13. The method of claim 8, further comprising depositing a
conductive layer into the via opening.
14. The method of claim 8, wherein the via opening has a trench
portion and a via portion underneath the trench portion.
15. A system to manufacture an electronic device, comprising: a
processing chamber comprising a pedestal to hold an electronic
device structure comprising a first metallization layer comprising
a set of first conductive lines extending along a first direction
on a first insulating layer on a substrate; a plasma source coupled
to the processing chamber to generate plasma; and a processor
coupled to the plasma source, the processor having a first
configuration to control recessing the first conductive lines, the
processor having a second configuration to control forming pillars
on the recessed first conductive lines, the processor having a
third configuration to control depositing a second insulating layer
between the pillars: the processor having a fourth configuration to
control removing the pillars to form trenches in the second
insulating layer, the processor having a fifth configuration to
control depositing a third insulating layer through the trenches
onto the recessed first conductive lines; and the processor having
a sixth configuration to control etching the third insulating layer
selectively relative to the second insulating layer to form a via
opening down to one of the first conductive lines.
16. The system of claim 15, wherein the via opening is self-aligned
along the first direction and a second direction, the second
direction crossing the first direction at an angle.
17. The system of claim 15, wherein the processor has a sixth
configuration to control selectively growing a seed layer on the
recessed first conductive lines, wherein the pillars are formed on
the seed layer.
18. The system of claim 15, wherein the processor has a seventh
configuration to control forming a hard mask layer on at least one
of the second insulating layer and the third insulating layer.
19. The system of claim 15, wherein the processor has an eight
configuration to control depositing a liner on the recessed first
conductive lines.
20. The system of claim 15, wherein the processor has a ninth
configuration to control depositing a conductive layer into the via
opening.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation Application of U.S. Ser.
No. 16/520,546, filed on Jul. 24, 2019, which is a Divisional
Application of U.S. application Ser. No. 16/272,059, filed on Feb.
11, 2019, which is a Divisional Application of U.S. application
Ser. No. 15/679,458, filed on Aug. 17, 2017, which claims priority
to U.S. Provisional Application No. 62/481,301, filed Apr. 4, 2017,
the entire disclosures of which are hereby incorporated by
reference herein.
TECHNICAL FIELD
[0002] Embodiments of the present disclosure pertain to the field
of electronic device manufacturing, and in particular, to an
integrated circuit (IC) manufacturing.
BACKGROUND
[0003] Generally, an integrated circuit (IC) refers to a set of
electronic devices, e.g., transistors formed on a small chip of
semiconductor material, typically, silicon. Typically, the IC
includes one or more layers of metallization having metal lines to
connect the electronic devices of the IC to one another and to
external connections. Typically, layers of the interlayer
dielectric material arc placed between the metallization layers of
the IC for insulation.
[0004] As the size of the IC decreases, the spacing between the
metal lines decreases. Typically, to manufacture an interconnect
structure, a planar process is used that involves aligning and
connecting one layer of metallization to another layer of
metallization.
[0005] Typically, patterning of the metal lines in the
metallization layer is performed independently from the vias above
that metallization layer. Conventional via manufacturing
techniques, however, cannot provide the full via self-alignment. In
the conventional techniques, the vias formed to connect lines in an
upper metallization layer to a lower metallization arc often
misaligned to the lines in the lower metallization layer. The
via-line misalignment increases via resistance and leads to
potential shorting to the wrong metal line. The via-line
misalignment causes device failures, decreases yield and increases
manufacturing cost.
SUMMARY
[0006] Methods and apparatuses to provide full via self-alignment
are described. In one embodiment, a first metallization layer
comprises a set of first conductive lines that extend along a first
direction on a first insulating layer on a substrate. A second
insulating layer is on the first insulating layer. A second
metallization layer comprises a set of second conductive lines on a
third insulating layer and on the second insulating layer above the
first metallization layer. The set of second conductive lines
extend along a second direction that crosses the first direction at
an angle. A via is between the first metallization layer and the
second metallization layer. The via is self-aligned along the
second direction to one of the first conductive lines.
[0007] In one embodiment, first conductive lines on a first
insulating layer on a substrate are recessed. The first conductive
lines extend along a first direction on the first insulating layer.
Pillars are formed on the recessed first conductive lines. A second
insulating layer is formed between the pillars. The pillars are
removed to form trenches in the second insulating layer. A third
insulating layer is deposited through the trenches onto the
recessed first conductive lines. The third insulating layer is
etched selectively relative to the second insulating layer to form
a via opening down to one of the first conductive lines.
[0008] In one embodiment, a system to manufacture an electronic
device comprises a processing chamber that comprises a pedestal to
hold an electronic device structure. The electronic device
structure comprises a first metallization layer that comprises a
set of first conductive lines that extend along a first direction
on a first insulating layer on a substrate. A plasma source is
coupled to the processing chamber to generate plasma. A processor
is coupled to the plasma source. The processor has a configuration
to control recessing the first conductive lines. The processor has
a configuration to control recessing the first conductive lines.
The processor has a configuration to control forming pillars on the
recessed first conductive lines. The processor has a configuration
to control depositing a second insulating layer between the
pillars. The processor has a configuration to control removing the
pillars to form trenches in the second insulating layer. The
processor has a configuration to control depositing a third
insulating layer through the trenches onto the recessed first
conductive lines. The processor has a sixth configuration to
control etching the third insulating layer selectively relative to
the second insulating layer to form a via opening down to one of
the first conductive lines.
[0009] Other features of the present disclosure will be apparent
from the accompanying drawings and from the detailed description
which follows.
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. The embodiments as described herein are illustrated by
way of example and not limitation in the figures of the
accompanying drawings in which like references indicate similar
elements.
[0011] FIG. 1A illustrates a top view and a cross-sectional view of
an electronic device structure to provide a fully self-aligned via
according to one embodiment.
[0012] FIG. 1B is a perspective view of the electronic device
structure depicted in FIG. 1A.
[0013] FIG. 2A is a view similar to FIG. 1A, after the conductive
lines are recessed according to one embodiment.
[0014] FIG. 2B is a view similar to FIG. 1B, after the conductive
lines are recessed according to one embodiment.
[0015] FIG. 3 is a view similar to FIG. 2A, after a liner is
deposited on the recessed conductive lines according to one
embodiment.
[0016] FIG. 4 is a view similar to FIG. 3, after a seed gapfill
layer is deposited on the liner according to one embodiment.
[0017] FIG. 5A is a view similar to FIG. 4, after portions of the
seed gapfill layer are removed to expose top portions of the
insulating layer according to one embodiment.
[0018] FIG. 5B is a perspective view of the electronic device
structure shown in FIG. 5A.
[0019] FIG. 6A is a view similar to FIG. 5A, after self-aligned
selective growth pillars are formed according to one
embodiment.
[0020] FIG. 6B is a view similar to FIG. 5B, after self-aligned
selective growth pillars are formed according to one
embodiment.
[0021] FIG. 7A is a view similar to FIG. 6A after an insulating
layer is deposited to overfill the gaps between the pillars
according to one embodiment.
[0022] FIG. 7B is a view similar to FIG. 6B, after an insulating
layer is deposited to overfill the gaps between the pillars
according to one embodiment.
[0023] FIG. 8A is a view similar to FIG. 7A, after a portion of the
insulating layer is removed to expose the top portions of the
pillars according to one embodiment.
[0024] FIG. 8B is a view similar to FIG. 6A, after an insulating
layer is deposited to underfill the gaps between the pillars
according to another embodiment.
[0025] FIG. 9A is a view similar to FIG. 8A after the self-aligned
selectively grown pillars are selectively removed to form trenches
according to one embodiment.
[0026] FIG. 9B is a perspective view of the electronic device
structure depicted in FIG. 9A.
[0027] FIG. 10A is a view similar to FIG. 9A after an insulating
layer is deposited into trenches according to one embodiment.
[0028] FIG. 10B is a view similar to FIG. 9B after an insulating
layer is deposited into trenches according to one embodiment.
[0029] FIG. 11 is a view similar to FIG. 10B after a hard mask
layer is deposited on an insulating layer according to one
embodiment.
[0030] FIG. 12A is a view similar to FIG. 11 after a mask layer is
deposited on an insulating layer on the patterned hard mask layer
according to one embodiment.
[0031] FIG. 12B is a cross-sectional view of FIG. 12A along an axis
B-B'.
[0032] FIG. 13A is a view similar to FIG. 12B after the insulating
layer is selectively etched according to one embodiment.
[0033] FIG. 13B is a view similar to FIG. 12A after the insulating
layer is selectively etched according to one embodiment.
[0034] FIG. 14A is a view similar to FIG. 10A after a mask layer is
deposited on a hard mask layer according to one embodiment.
[0035] FIG. 14B is a top view of the electronic device structure
depicted in FIG. 14A.
[0036] FIG. 15A is a view similar to FIG. 14A after portions of the
hard mask layer and the insulating layer are removed according to
one embodiment.
[0037] FIG. 15B is a top view of the electronic device structure
depicted in FIG. 15A.
[0038] FIG. 16A is a view similar to FIG. 15A after a fully
self-aligned opening is formed in insulating layer according to one
embodiment.
[0039] FIG. 16B is a top view of the electronic device structure
depicted in FIG. 16A.
[0040] FIG. 17A is a view similar to FIG. 16A after an upper
metallization layer comprising conductive lines extending along a Y
axis is formed according to one embodiment.
[0041] FIG. 17B is a top view of the electronic device structure
depicted in FIG. 17A.
[0042] FIG. 18A is a view similar to FIG. 10A after a mask layer is
deposited on a hard mask layer according to one embodiment.
[0043] FIG. 18B is a top view of the electronic device structure
depicted in FIG. 18A.
[0044] FIG. 19A is a view similar to FIG. 18A after portions of the
hard mask layer and the insulating layer are removed according to
one embodiment.
[0045] FIG. 19B is a top view of the electronic device structure
depicted in FIG. 19A.
[0046] FIG. 20A is a view similar to FIG. 19A after forming a
planarization filling layer and mask layer according to one
embodiment.
[0047] FIG. 20B is a top view of the electronic device structure
depicted in FIG. 20A.
[0048] FIG. 21A is a view similar to FIG. 20A after a fully
self-aligned opening is formed in insulating layer according to one
embodiment.
[0049] FIG. 21B is a top view of the electronic device structure
depicted in FIG. 21A.
[0050] FIG. 22A is a view similar to FIG. 21A after an upper
metallization layer comprising conductive lines extending along a Y
axis is formed according to one embodiment.
[0051] FIG. 22B is a top view of the electronic device structure
depicted in FIG. 22A.
[0052] FIG. 23 shows a block diagram of a plasma system to provide
a fully self-aligned via according to one embodiment.
DETAILED DESCRIPTION
[0053] Before describing several exemplary embodiments of the
disclosure, it is to be understood that the disclosure is not
limited to the details of construction or process steps set forth
in the following description. The disclosure is capable of other
embodiments and of being practiced or being carried out in various
ways.
[0054] 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, amorphous silicon, 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
under-layer formed on the substrate as disclosed in more detail
below, and the term "substrate surface" is intended to include such
under-layer 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.
[0055] As used in this specification and the appended claims, the
terms "precursor", "reactant", "reactive gas" and the like are used
interchangeably to refer to any gaseous species that can react with
the substrate surface.
[0056] Methods and apparatus to provide fully self-aligned vias are
described. In one embodiment, a first metallization layer
comprising a set of first conductive lines extending along a first
direction on a first insulating layer on a substrate is formed. A
second insulating layer is formed on the first insulating layer. A
second metallization layer comprising a set of second conductive
lines on a third insulating layer above the first metallization
layer is formed. The set of second conductive lines extend along a
second direction. A via is formed between the first metallization
layer and the second metallization layer. The via is self-aligned
along the second direction to one of the first conductive lines.
The via is self-aligned along the first direction to one of the
second conductive lines, as described in further detail below. In
one embodiment, the first and second directions cross each other at
an angle. In one embodiment, the first direction and second
direction are substantially orthogonal to each other.
[0057] In one embodiment, a fully self-aligned via is fabricated
using a selective pillar growth technique. In one embodiment, the
conductive lines on a first insulating layer on a substrate are
recessed. The conductive lines extend along a first direction on
the first insulating layer. Pillars are formed on the recessed
conductive lines. A second insulating layer is deposited between
the pillars. A third insulating layer is deposited on the second
insulating layer. The third insulating layer is selectively etched
relative to the second insulating layer to form a via opening down
to one of the conductive lines, as described in further detail
below.
[0058] In one embodiment, a fully self-aligned via is the via that
is self-aligned along at least two directions to the conductive
lines in a lower and an upper metallization layer. In one
embodiment, the fully self-aligned via is defined by a hard mask in
one direction and the underlying insulating layer in another
direction, as described in further detail below.
[0059] Comparing to the conventional techniques, the embodiments to
provide the fully self-aligned vias advantageously eliminate the
via misalignment issues and avoid shortening to the wrong metal
line. The fully self-aligned vias provide lower via resistance and
capacitance benefits over the conventional vias. Embodiments of the
self-aligned vias provide the full alignment between the vias and
the conductive lines of the metallization layers that is
substantially error free that advantageously increase the device
yield and reduce the device cost.
[0060] In the following description, numerous specific details,
such as specific materials, chemistries, dimensions of the
elements, etc. are set forth in order to provide thorough
understanding of one or more of the embodiments of the present
disclosure. It will be apparent, however, to one of ordinary skill
in the art that the one or more embodiments of the present
disclosure maybe practiced without these specific details. In other
instances, semiconductor fabrication processes, techniques,
materials, equipment, etc., have not been descried in great details
to avoid unnecessarily obscuring of this description. Those of
ordinary skill in the art, with the included description, will be
able to implement appropriate functionality without undue
experimentation.
[0061] While certain exemplary embodiments of the disclosure are
described and shown in the accompanying drawings, it is to be
understood that such embodiments are merely illustrative and not
restrictive of the current disclosure, and that this disclosure is
not restricted to the specific constructions and arrangements shown
and described because modifications may occur to those ordinarily
skilled in the art.
[0062] Reference throughout the specification to "one embodiment",
"another embodiment", or "an embodiment" means that a particular
feature, structure, or characteristic described in connection with
the embodiment is included in a least one embodiment of the present
disclosure. Thus, the appearance of the phrases "in one embodiment"
or "in an embodiment" in various places throughout the
specification are not necessarily all referring to the same
embodiment of the disclosure. Furthermore, the particular features,
structures, or characteristics may be combined in any suitable
manner in one or more embodiments.
[0063] Moreover, inventive aspects lie in less than all the
features of a single disclosed embodiment of the disclosure. Thus,
the claims following the Detailed Description are hereby expressly
incorporated into this Detailed Description, with each claim
standing on its own as a separate embodiment of this disclosure.
While the disclosure has been described in terms of several
embodiments, those skilled in the art will recognize that the
disclosure if not limited to the embodiments described, but can be
practiced with modification and alteration within the spirit and
scope of the appended claims. The description is thus to be
regarded as illustrative rather than limiting.
[0064] FIG. 1A illustrates a top view 100 and a cross-sectional
view 110 of an electronic device structure to provide a fully
self-aligned via according to one embodiment. The cross-sectional
view 110 is along an axis A-A', as depicted in FIG. 1A. FIG. 1B is
a perspective view 120 of the electronic device structure depicted
in FIG. 1A. A lower metallization layer (Mx) comprises a set of
conductive lines 103 that extend along an X axis (direction) 121 on
an insulating layer 102 on a substrate 101, as shown in FIGS. 1A
and 1B. As shown in FIG. 1B, X axis (direction) 121 crosses Y axis
(direction) 122 at an angle 123. In one embodiment, angle 123 is
about 90 degrees. In another embodiment, angle 123 is an angle that
is other than the 90 degrees angle. The insulating layer 102
comprises trenches 104. The conductive lines 103 are deposited in
trenches 104.
[0065] In an embodiment, the substrate 101 comprises a
semiconductor material, e.g., silicon (Si), carbon (C), germanium
(Ge), silicon germanium (SiGe), galloum arsenide (GaAs), InP, GaAs,
InGaAs, InAlAs, other semiconductor material, or any combination
thereof. In an embodiment, substrate 101 is a
semiconductor-on-isolator (SOI) substrate including a bulk lower
substrate, a middle insulation layer, and a top monocrystalline
layer. The top monocrystalline layer may comprise any material
listed above, e.g., silicon. In various embodiments, the substrate
can be, e.g., an organic. A ceramic, a glass, or a semiconductor
substrate. Although a few examples of materials from which the
substrate may be formed are described here, any material that may
serve as a foundation upon which passive and active electronic
devices (e.g., transistors, memories, capacitors, inductors,
resistors, switches, integrated circuits, amplifiers,
optoelectronic devices, or any other electronic devices) may be
built falls within the spirit and scope of the present
disclosure.
[0066] In one embodiment, substrate 101 includes one or more
metallization interconnect layers for integrated circuits. In at
least some embodiments, the substrate 101 includes interconnects,
for example, vias, configured to connect the metallization layers.
In at least some embodiments, the substrate 101 includes electronic
devices, e.g., transistors, memories, capacitors, resistors,
optoelectronic devices, switches, and any other active and passive
electronic devices that are separated by an electrically insulating
layer, for example, an interlayer dielectric, a trench insulation
layer, or any other insulating layer known to one of ordinary skill
in the art of the electronic device manufacturing. In one
embodiment, the substrate includes one or more buffer layers to
accommodate for a lattice mismatch between the substrate 101 and
one or more layers above substrate 101 and to confine lattice
dislocations and defects.
[0067] Insulating layer 102 can be any material suitable to
insulate adjacent devices and prevent leakage. In one embodiment,
electrically insulating layer 102 is an oxide layer, e.g., silicon
dioxide, or any other electrically insulating layer determined by
an electronic device design. In one embodiment, insulating layer
102 comprises an interlayer dielectric (ILD). In one embodiment,
insulating layer 102 is a low-k dielectric that includes, but is
not limited to, materials such as, e.g., silicon dioxide, silicon
oxide, carbon doped oxide ("CDO"), e.g., carbon doped silicon
dioxide, porous silicon dioxide, silicon nitride, or any
combination thereof.
[0068] In one embodiment, insulating layer 102 includes a
dielectric material having a k-value less than 5. In one
embodiment, insulating layer 102 includes a dielectric material
having a k-value less than 2. In at least some embodiments,
insulating layer 102 includes a nitride, oxide, a polymer,
phosphosilicate glass, fluourosilicate (SiOF) glass, organosilicate
glass (SiOCH), other electrically insulating layer determined by an
electronic device design, or any combination thereof. In at least
some embodiments, insulating layer 102 may include polyimide,
epoxy, photodefinable materials, such as benzocyclobutene (BCB),
and WPR-series materials, or spin-on-glass.
[0069] In one embodiment, insulating layer 102 is a low-k
interlayer dielectric to isolate one metal line from other metal
lines on substrate 101. In one embodiment, the thickness of the
layer 102 is in an approximate range from about 10 nanometers (nm)
to about 2 microns (.mu.m).
[0070] In an embodiment, insulating layer 102 is deposited using
one of deposition techniques, such as but not limited to a chemical
vapor deposition ("CVD"), a physical vapor deposition ("PVD"),
molecular beam epitaxy ("MBE"), metalorganic chemical vapor
deposition ("MOCVD"), atomic layer deposition ("ALD"), spin-on, or
other insulating deposition techniques known to one of ordinary
skill in the art of microelectronic device manufacturing.
[0071] In one embodiment, the lower metallization layer Mx
comprising conductive lines 103 (i.e., metal lines) is a part of a
back end metallization of the electronic device. In one embodiment,
the insulating layer 102 is patterned and etched using a hard mask
to form trenches 104 using one or more patterning and etching
techniques known to one of ordinary skill in the art of
microelectronic device manufacturing. In one embodiment, the size
of trenches in the insulating layer 102 is determined by the size
of conductive lines formed later on in a process.
[0072] In one embodiment, forming the conductive lines 201 involves
filling the trenches 104 with a layer of conductive material. In
one embodiment, a base layer (not shown) is first deposited on the
internal sidewalls and bottom of the trenches 104, and then the
conductive layer is deposited on the base layer. In one embodiment,
the base layer includes a conductive seed layer (not shown)
deposited on a conductive barrier layer (not shown). The seed layer
can include copper, and the conductive barrier layer can include
aluminum, titanium, tantalum, tantalum nitride, and the like
metals. The conductive barrier layer can be used to prevent
diffusion of the conductive material from the seed layer, e.g.,
copper, into the insulating layer 102. Additionally, the conductive
barrier layer can be used to provide adhesion for the seed layer
(e.g., copper).
[0073] In one embodiment, to form the base layer, the conductive
barrier layer is deposited onto the sidewalls and bottom of the
trenches 104, and then the seed layer is deposited on the
conductive barrier layer. In another embodiment, the conductive
base layer includes the seed layer that is directly deposited onto
the sidewalls and bottom of the trenches 104. Each of the
conductive barrier layer and seed layer may be deposited using any
think film deposition technique known to one of ordinary skill in
the art of semiconductor manufacturing, e.g., sputtering, blanket
deposition, and the like. In one embodiment, each of the conductive
barrier layer and the seed layer has the thickness in an
approximate range from about 1 nm to about 100 nm. In one
embodiment, the barrier layer may be a thin dielectric that has
been etched to establish conductivity to the metal layer below. In
one embodiment, the barrier layer may be omitted altogether and
appropriate doping of the copper line may be used to make a
"self-forming barrier".
[0074] In one embodiment, the conductive layer e.g., copper, is
deposited onto the seed layer of base layer of copper, by an
electroplating process. In one embodiment, the conductive layer is
deposited into the trenches 104 using a damascene process known to
one of ordinary skill in the art of microelectronic device
manufacturing. In one embodiment, the conductive layer is deposited
onto the seed layer in the trenches 104 using a selective
deposition technique, such as but not limited to electroplating,
electroless, A CVD, PVD, MBE, MOCVD, ALD, spin-on, or other
deposition techniques know to one of ordinary skill in the art of
microelectronic device manufacturing.
[0075] In one embodiment, the choice of a material for conductive
layer for the conductive lines 103 determines the choice of a
material for the seed layer. For example, if the material for the
conductive lines 103 includes copper, the material for the seed
layer also includes copper. In one embodiment, the conductive lines
103 include a metal, for example, copper (Cu), ruthenium (Ru),
nickel (Ni), cobalt (Co), chromium (Cr), iron (Fe), manganese (Mn),
titanium (Ti), aluminum (Al), hafnium (Hf), tantalum (Ta),
tungsten(W), vandium (V), molybdenum (Mo), palladium (Pd), gold
(Au), silver (Ag), platinum (Pt), indium (In), tin (Sn), lead (Pd),
antimony (Sb), bismuth (Bi), zinc (Zn), cadmium (Cd), or any
combination thereof.
[0076] In alternative embodiments, examples of the conductive
materials that may be used for the conductive lines 103 of the
metallization layer Mx are, but not limited to, metals, e.g.,
copper, tantalum, tungsten, ruthenium, titanium, hafnium,
zirconium, aluminum, silver, tin, lead, metal alloys, metal
carbides, e.g., hafnium carbide, zirconium carbide, titanium
carbide, tantalum carbide, aluminum carbide, other conductive
materials, or any combination thereof.
[0077] In one embodiment, portions of the conductive layer and the
base layer are removed to even out top portions of the conductive
lines 103 with top portions of the insulating layer 102 using a
chemical-mechanical polishing ("CMP") technique known to one of
ordinary skill in the art of microelectronic device
manufacturing.
[0078] In one non-limiting example, the thickness of the conductive
lines 103 is in an approximate range from about 15 nm to about 1000
nm. In one non-limiting example, the thickness of the conductive
lines 103 is from about 20 nm to about 200 nm. In one non-limiting
example, the width of the conductive lines 103 is in an approximate
range from about 5 nm to about 500 nm. In one non-limiting example,
the spacing (pitch) between the conductive lines 103 is from about
2 nm to about 500 nm. In more specific non-limiting example, the
spacing (pitch) between the conductive lines 103 is from about 5 nm
to about 50 nm.
[0079] In an embodiment, the lower metallization layer Mx is
configured to connect to other metallization layers (not shown). In
an embodiment, the metallization layer Mx is configured to provide
electrical contact to electronic devices, e.g., transistor,
memories, capacitors, resistors, optoelectronic devices, switches,
and any other active and passive electronic devices that are
separated by an electrically insulating layer, for example, an
interlayer dielectric, a trench insulation layer, or any other
insulating layer known to one of ordinary skill in the art of
electronic device manufacturing.
[0080] FIG. 2A is a view 200 similar to view 110 of FIG. 1A, after
the conductive lines 103 are recessed according to one embodiment.
FIG. 2B is a view 210 similar to FIG. 1 B, after the conductive
lines 103 are recessed according to one embodiment. The conductive
lines 103 are recessed to a predetermined depth to form recessed
conductive lines 201. As shown in FIGS. 2A and 2B, trenches 202 are
formed in the insulating layer 102. Each trench 202 has sidewalls
204 that are portions of insulating layer 102 and a bottom that is
a top surface 203 of the recessed conductive line 201.
[0081] In one embodiment, the depth of the trenches 202 is from
about 10 nm to about 500 nm. In one embodiment, the depth of the
trenches 202 is from about 10% to about 100% of the thickness of
the conductive lines. In one embodiment, the conductive lines 103
are recessed using one or more of wet etching, dry etching, or a
combination thereof techniques known to one of ordinary skill in
the art of electronic device manufacturing.
[0082] FIG. 3 is a view 300 similar to FIG. 2A, after a liner 301
is deposited on the recessed conductive lines 201 according to one
embodiment. Liner 301 is deposited on the bottom and sidewalls of
the trenches 202, as shown in FIG. 3.
[0083] In one embodiment, liner 301 is deposited to protect the
conductive lines 201 from changing the properties later on in a
process (e.g., during tungsten deposition, or other processes). In
one embodiment, liner 301 is a conductive liner. In another
embodiment, liner 301 is a non-conductive liner. In one embodiment,
when liner 301 is a non-conductive liner, the liner 301 is removed
later on in a process, as described in further detail below. In one
embodiment, liner 301 includes titanium nitride (TiN), titanium
(Ti), tantalum (Ta), tantalum nitride (TaN), or any combination
thereof. In another embodiment, liner 301 is an oxide, e.g.,
aluminum oxide (AlO), titanium oxide (TiO.sub.2). In yet another
embodiment, liner 301 is a nitride, e.g., silicon nitride (SiN). In
an embodiment, the liner 301 is deposited to the thickness from
about 0.5 nm to about 10 nm.
[0084] In an embodiment, the liner 301 is deposited using an atomic
layer deposition (ALD) technique. In one embodiment, the liner 301
is deposited using one of deposition techniques, such as but no
limited to a CVD, PVD, MBE, MOCVD, spin-on, or other liner
deposition techniques know to one of ordinary skill in the art of
microelectronic device manufacturing.
[0085] FIG. 4 is a view 400 similar to FIG. 3, after a seed gapfill
layer 401 is deposited on the liner 301 according to one
embodiment. In one embodiment, seed gapfill layer 401 is a
self-aligned selective growth seed film. As shown in FIG. 4, seed
gapfill layer 401 is deposited on liner 301 on the top surface 203
of the recessed conductive lines 201, the sidewalls 204 of the
trenches 202 and top portions of the insulating layer 102. In one
embodiment, seed gapfill layer 401 is a tungsten (W) layer, or
other seed gapfill layer to provide selective growth pillars. In
some embodiments, seed gapfill layer 401 is a metal film or a metal
containing film. Suitable metal films include, but are not limited
to, films including one or more of cobalt (Co), molybdenum (Mo),
tungsten (W), tantalum (Ta), titanium (Ti), ruthenium (Ru), rhodium
(Rh), copper (Cu), iron (Fe), manganese (Mn), vanadium (V), niobium
(Nb), hafnium (Hf), zirconium (Zr), yttrium (Y), aluminum (Al), tin
(Sn), chromium (Cr), lanthanum (La), or any combination thereof. In
some embodiments, seed gapfill layer 401 comprises is a tungsten
(W) seed gapfill layer.
[0086] In one embodiment, the seed gapfill layer 401 is deposited
using one of deposition techniques, such as but not limited to an
ALD, a CVD, PVD, MBE, MOCVD, spin-on or other liner deposition
techniques known to one of ordinary skill in the art of
microelectronic device manufacturing.
[0087] FIG. 5A is a view 500 similar to FIG. 4, after portions of
the seed gapfill layer 401 are removed to expose top portions of
the insulating layer 102 according to one embodiment. FIG. 5B is a
perspective view of the electronic device structure shown in FIG.
5A. In one embodiment, the portions of the seed gapfill layer 401
are removed using one of the chemical-mechanical polishing (CMP)
techniques known to one of ordinary skill in the art of
microelectronic device manufacturing.
[0088] FIG. 6A is a view 600 similar to FIG. 5A, and FIG. 6B is a
view 610 similar to FIG. 5B, after self-aligned selective growth
pillars 601 are formed using the seed gapfill layer 401 on the
liner 301 on the recessed conductive lines 201 according to one
embodiment. As shown in FIGS. 6A and 6B, an array of the
self-aligned selective growth pillars 601 has the same pattern as
the set of the conductive lines 201. As shown in FIGS. 6A and 6B,
the pillars 601 extend substantially orthogonally from the top
surfaces of the conductive lines 201. As shown in FIGS. 6A and 6B,
the pillars 601 extend along the same direction as the conductive
lines 201. As shown in FIGS. 6A and 6B, the pillars are separated
by gaps 603.
[0089] In one embodiment, the pillars 601 are selectively grown
from the seed gapfill layer 401 on portions of the liner 301 on the
conductive lines 201. The pillars 601 are not grown on portions of
the liner 301 on the insulating layer 102, as shown in FIGS. 6A and
6B. In one embodiment, portions of the seed gapfill layer 401 above
the conductive lines 201 are expanded for example, by oxidation,
nitridation, or other process to grow pillars 601. In one
embodiment, the seed gap fill layer 401 is oxidized by exposure to
an oxidizing agent or oxidizing conditions to transform the metal
or metal containing seed gapfill layer 401 to metal oxide pillars
601. In one embodiment, pillars 601 include an oxide of one or more
metals listed above. In more specific embodiment, pillars 601
include tungsten oxide (e.g., WO, WO.sub.3 and other tungsten
oxide).
[0090] The oxidizing agent can be any suitable oxidizing agent
including, but not limited to, O.sub.2, O.sub.3, N.sub.2O,
H.sub.2O, H.sub.2O.sub.2, CO, CO.sub.2, NH.sub.3, N.sub.2/Ar,
N.sub.2/He, N.sub.2/Ar/He or any combination thereof. In some
embodiments, the oxidizing conditions comprise a thermal oxidation,
plasma enhanced oxidation, remote plasma oxidation, microwave and
radio-frequency oxidation (e.g., inductively coupled plasma (ICP),
capacitively coupled plasma (CCP)).
[0091] In one embodiment, the pillars 601 are formed by oxidation
of the seed gapfill layer at any suitable temperature depending on,
for example, the composition of the seed gapfill layer and the
oxidizing agent. In some embodiments, the oxidation occurs at a
temperature in an approximate range of about 25 degrees C. to about
800 degrees C. In some embodiments, the oxidation occurs at a
temperature greater than or equal to about 150.degree. C.
[0092] In one embodiment, the height 602 of the pillars 601 is in
an approximate range from about 5 angstroms (.ANG.) to about 10
microns (.mu.m).
[0093] FIG. 7A is a view 700 similar to FIG. 6A, and FIG. 7B is a
view 710 similar to FIG. 6B, after an insulating layer 701 is
deposited to overfill the gaps 603 between the pillars 601
according to one embodiment. As shown in FIGS. 7A and 7B,
insulating layer 701 is deposited on the opposing sidewalls 702 and
top portions 703 of the pillars 601 and through the gaps 603 on the
portions of the insulating layer 102 and liner 301 between the
pillars 601.
[0094] In one embodiment, insulating layer 701 is a low-k gapfill
layer. In one embodiment, insulating layer 701 is a flowable
silicon oxide (FSiOx) layer. In at least some embodiments,
insulating layer 701 is an oxide layer, e.g., silicon dioxide, or
any other electrically insulating layer determined by an electronic
device design. In one embodiment, insulating layer 701 is an
interlayer dielectric (ILD). In one embodiment, insulating layer
701 is a low-k dielectric that includes, but is not limited to,
materials such as, e.g., silicon dioxide, silicon oxide, a carbon
based material, e.g, a porous carbon film, carbon doped oxide
("CDO"), e.g., carbon doped silicon dioxide, porous silicon
dioxide, porous silicon oxide carbide hydride (SiOCH), silicon
nitride, or any combination thereof. In one embodiment, insulating
layer 701 is a dielectric material having k-value less than 3. In
more specific embodiment, insulating layer 701 is a dielectric
material having k-value in an approximate range from about 2.2 to
about 2.7. In one embodiment, insulating layer 701 includes a
dielectric material having k-value less than 2. In one embodiment,
insulating layer 701 represents one of the insulating layers
described above with respect to insulating layer 102.
[0095] In one embodiment, insulating layer 701 is a low-k
interlayer dielectric to isolate one metal line from other metal
lines. In one embodiment, insulating layer 701 is deposited using
one of deposition techniques, such as but not limited to a CVD,
spin-on, an ALD, PVD. MBE, MOCVD, or other low-k insulating layer
deposition techniques known to one of ordinary skill in the art of
microelectronic device manufacturing.
[0096] FIG. 8A is a view 800 similar to FIG. 7A, after a portion of
the insulating layer 701 is removed to expose the top portions 703
of the pillars 601 according to one embodiment. In one embodiment,
the portion of the insulating layer 701 is removed using a CMP
technique known to one of ordinary skill in the art of
microelectronic device manufacturing. In one embodiment, the
portion of the insulating layer 701 is etched back to expose the
top portions 703 of the pillars 601 using one or more of the dry
and wet etching techniques known to one of ordinary skill in the
art of microelectronic device manufacturing.
[0097] FIG. 8B is a view 800 similar to FIG. 6A, after an
insulating layer 701 is deposited to underfill (partially fill) the
gaps 603 between the pillars 601 according to another embodiment.
As shown in FIG. 8B, insulating layer 701 is deposited through gaps
603 on lower portions of opposing sidewalls 702 the pillars 601 and
the portions of the insulating layer 102 and liner 301 between
pillars 601. In one embodiment, insulating layer 701 is deposited
to a predetermined thickness to expose the top portions 703 and
upper portions of the opposing sidewalls 702 of the pillars
601.
[0098] In one embodiment, insulating layer 701 is deposited using
one of deposition techniques, such as but not limited to a CVD,
spin-on, an ALD, PVD, MBE, MOCVD, or other low-k insulating layer
deposition techniques known to one of ordinary skill in the art of
microelectronic device manufacturing. In another embodiment,
insulating layer 701 is deposited to overfill the gaps 603 between
the pillars 601, as described with respect to FIG. 7A, and then a
portion of the insulating layer 701 is etched back to expose upper
portions 811 of the sidewalls 702 and top portions 703 of the
pillars 601 using one or more of the dry and wet etching techniques
known to one of ordinary skill in the art of microelectronic device
manufacturing.
[0099] FIG. 9A is a view similar to FIG. 8A after the self-aligned
selectively grown pillars 601 are selectively removed to form
trenches 901 according to one embodiment. FIG. 9B is a perspective
view of the electronic device structure depicted in FIG. 9A. As
shown in FIGS. 9A and 9B, the pillars 601 are removed selectively
to the insulating layer 701 and liner 301. In another embodiment,
when liner 301 is a non-conductive liner, liner 301 is removed. In
one embodiment, the pillars 601 and liner 301 are removed
selectively to the insulating layers 701 and 102 and conductive
lines 201. As shown in FIGS. 9A and 9B, trenches 901 are formed in
the insulating layers 701 and 102. Trenches 901 extend along the
recessed conductive lines 201. As shown in FIGS. 9A and 9B, each
trench 901 has a bottom that is a bottom portion 902 of liner 301
and opposing sidewalls that include a sidewall portion 903 of liner
301 and a portion of insulating layer 701. In another embodiment,
when liner 301 is removed, each trench 901 has a bottom that is
recessed conductive line 201 and opposing sidewalls that include
portions of insulating layers 701 and 102. Generally, the aspect
ratio of the trench refers to the ratio of the depth of the trench
to the width of the trench. In one embodiment, the aspect ratio of
each trench 901 is in an approximate range from about 1:1 to about
200:1.
[0100] In one embodiment, the pillars 601 are selectively removed
using one or more of the dry and wet etching techniques known to
one of ordinary skill in the art of electronic device
manufacturing. In one embodiment, the pillars 601 are selectively
wet etched by e.g., 5 wt % of ammonium hydroxide (NH.sub.4OH)
aqueous solution at the temperature of about 80 degrees C. In one
embodiment, hydrogen peroxide (H.sub.2O.sub.2) is added to the 5 wt
% NH.sub.4OH aqueous solution to increase the etching rate of the
pillars 601. In one embodiment, the pillars 601 are selectively wet
etched using hydrofluoric acid (HF) and nitric acid (HNO.sub.3) in
a ratio of 1:1. In one embodiment, the pillars 601 are selectively
wet etched using HF and HNO.sub.3 in a ratio of 3:7 respectively.
In one embodiment, the pillars 601 are selectively wet etched using
HF and HNO.sub.3 in a ratio of 4:1, respectively. In one
embodiment, the pillars 601 are selectively wet etched using HF and
HNO.sub.3 in a ratio of 30%:70%, respectively. In one embodiment,
the pillars 601 including tungsten, titanium or both titanium and
tungsten are selectively wet etched using NH.sub.4OH and
H.sub.2O.sub.2 in a ratio of 1:2, respectively. In one embodiment,
the pillars 601 are selectively wet etched using 305 grams of
potassium ferricyanide (K.sub.3Fe(CN).sub.6), 44.5 grams of sodium
hydroxide (NaOH) and 1000 ml of water (H.sub.2O). In one
embodiment, the pillars 601 are selectively wet etched using
diluted or concentrated one or more of the chemistries including
hydrochloric acid (HCl), HNO.sub.3, surfuric acid
(H.sub.2SO.sub.4), HF, and H.sub.2O.sub.2. In one embodiment, the
pillars 601 are selectively wet etched using HF, HNO.sub.3 and
acetic acid (HAc) in a ratio of 4:4:3, respectively. In one
embodiment, the pillars 601 are selectively dry etched using a
bromotrifluoromethane (CBrF3) reactive ion etching (RIE) technique.
In one embodiment, the pillar 601 are selectively dry etched using
a chlorine, fluorine, bromine or any combination thereof based
chemistries. In one embodiment, the pillars 601 are selectively wet
etched using hot or warm Aqua Regia mixture including HCl and
HNO.sub.3 in a ratio of 3:1, respectively. In one embodiment, the
pillars 601 are selectively etched using alkali with oxidizers
(potassium nitrate (KNO.sub.3) and lead dioxide (PbO.sub.2)). In
one embodiment, the liner 301 is selectively removed using one or
more of the dry and wet etching techniques known to one of ordinary
skill in the art of electronic device manufacturing.
[0101] FIG. 10A is a view 1000 and FIG. 10B is a view 1010 that are
similar to FIGS. 9A and 9B respectively after an insulating layer
1001 is deposited into trenches 901 according to one embodiment. As
shown in FIGS. 10A and 10B, insulating layer 1001 overfills the
trenches 901 so that portions of the insulating layer 1001 are
deposited on the top portions of the insulating layer 701. In one
embodiment, the thickness of the insulating layer 1001 is greater
or similar to the thickness of the insulating layer 701. In one
embodiment, the thickness 1002 is at least two or three times
greater than the thickness of the insulating layer 701. In another
embodiment, the portions of the insulating layer 1001 are removed
using one or more of the CMP or a back etch techniques to even out
with the top portions of the insulating layer 701, and then other
insulating layer (not shown) is deposited onto the top portions of
the insulating layer 701 and insulating layer 1001. As shown in
FIGS. 10A and 10B, insulating layer 1001 is deposited on the
sidewalls and bottom of the trenches 901. As shown in FIGS. 10A and
10B, the insulating layer 1001 is deposited on the liner 301 and
portions of the insulating layer 701. In another embodiment, when
the liner 301 is removed, the insulating layer 1001 is directly
deposited on the recessed lines 201 and portions of the insulating
layer 102 and insulating layer 701. In one embodiment, the
insulating layer 1001 is etch selective to the insulating layer
701. Generally, etch selectivity between two materials is defined
as the ratio between their etching rates at similar etching
conditions. In one embodiment, the ratio of the etching rate of the
insulating layer 1001 to that of the insulating layer 701 is at
least 5:1. In one embodiment, the ratio of the etching rates of the
insulating layer 1001 to that of the insulating layer 701 is in an
approximate range from about 2:1 to about 20:1.
[0102] In one embodiment, insulating layer 1001 is a low-k gapfill
layer. In one embodiment, insulating layer 1001 is a flowable
silicon oxide carbide (FSiOC) layer. In some other embodiments,
insulating layer 1001 is an oxide layer, e.g., silicon dioxide, or
any other electrically insulating layer determined by an electronic
device design. In one embodiment, insulating layer 1001 is an
interlayer dielectric (ILD). In one embodiment, insulating layer
1001 is a low-k dielectric that includes, but is not limited to,
materials such as, e.g., silicon dioxide, silicon oxide, a carbon
based material, e.g., a porous carbon film carbon doped oxide
("CDO"), e.g., carbon doped silicon dioxide, porous silicon
dioxide, porous silicon oxide carbide hydride (SiOCH), silicon
nitride, or any combination thereof. In one embodiment, insulating
layer 1001 is a dielectric material having k-value less than 3. In
more specific embodiment, insulating layer 1001 is a dielectric
material having k-value in an approximate range from about 2.2 to
about 2.7. In one embodiment, insulating layer 1001 includes a
dielectric material having k-value less than 2. In one embodiment,
insulating layer 1001 represents one of the insulating layers
described above with respect to insulating layer 102 and insulating
layer 701.
[0103] In one embodiment, insulating layer 1001 is a low-k
interlayer dielectric to isolate one metal line from other metal
lines. In one embodiment, insulating layer 1001 is deposited using
one of deposition techniques, such as but not limited to a CVD,
spin-on, an ALD, PVD, MBE, MOCVD, or other low-k insulating layer
deposition techniques known to one of ordinary skill in the art of
microelectronic device manufacturing.
[0104] FIG. 11 is a view similar to FIG. 10B after a hard mask
layer 1101 is deposited on insulating layer 1001 according to one
embodiment. FIG. 11 is different from FIG. 10B in that the liner
301 is removed, so that insulating layer 1001 is directly deposited
on the recessed lines 201 and portions of the insulating layer 102
and insulating layer 701, as described above. In one embodiment,
hard mask layer 1101 is a metallization layer hard mask. As shown
in FIG. 11, the hard mask layer 1101 is patterned to define a
plurality of trenches 1102. As shown in FIG. 11, the trenches 1102
extend along an Y axis (direction) 122 that crosses an X axis
(direction) 122 at an angle. In one embodiment, direction 122 is
substantially perpendicular to direction 121. In one embodiment,
patterned hard mask layer 1101 is a carbon hard mask layer, a metal
oxide hard mask layer, a metal nitride hard mask layer, a silicon
nitride hard mask layer, a silicon oxide hard mask layer, a carbide
hard mask layer, or other hard mask layer known to one of ordinary
skill in the art of microelectronic device manufacturing. In one
embodiment, the patterned hard mask layer 1101 is formed using one
or more hard mask patterning techniques known to one of ordinary
skill in the art of microelectronic device manufacturing. In one
embodiment, the insulating layer 1001 is etched through a patterned
hard mask layer to form trenches 104 using one or more of etching
techniques known to one of ordinary skill in the art of
microelectronic device manufacturing. In one embodiment, the size
of trenches in the insulating layer 1001 is determined by the size
of conductive lines formed later on in a process.
[0105] FIG. 12A is a view similar to FIG. 11, after a mask layer
1202 is deposited on an insulating layer 1201 on a patterned hard
mask layer 1101 according to one embodiment. FIG. 12B is a
cross-sectional view of FIG. 12A along an axis B-B'.
[0106] As shown in FIGS. 12A and 12B, an opening 1203 is formed in
mask layer 1202. Opening 1203 is formed above one of the conductive
lines 201, as shown in FIGS. 12A and 12B. In one embodiment, the
opening 1203 defines a trench portion of the fully self-aligned via
formed later on in a process.
[0107] In one embodiment, mask layer 1202 includes a photoresist
layer. In one embodiment, mask layer 1202 includes one or more hard
mask layers. In one embodiment, the insulating layer 1201 is a hard
mask layer. In one embodiment, insulating layer 1201 includes a
bottom anti-reflective coating (BARC) layer. In one embodiment,
insulating layer 1201 includes a titanium nitride (TiN) layer, a
tungsten carbide (WC) layer, a tungsten bromide carbide (WBC)
layer, a carbon hard mask layer, a metal oxide hard mask layer, a
metal nitride hard mask layer, a silicon nitride hard mask layer, a
silicon oxide hard mask layer, a carbide hard mask layer, other
hard mask layer, or any combination thereof. In one embodiment,
insulating layer 1201 represents one of the insulating layers
described above. In one embodiment, mask layer 1202 is deposited
using one or more mask layer deposition techniques known to one of
ordinary skill in the art of microelectronic device manufacturing.
In one embodiment, insulating layer 1201 is deposited using one of
deposition techniques, such as but not limited to a CVD, PVD, MBE,
NOCVD, spin-on, or other insulating layer deposition techniques
known to one of ordinary skill in the art of microelectronic device
manufacturing. In one embodiment, the opening 1203 is formed using
one or more of the patterning and etching techniques known to one
of ordinary skill in the art of microelectronic device
manufacturing.
[0108] FIG. 13A is a view 1300 similar to FIG. 12B after the
insulating layer 1201 and insulating layer 1101 are selectively
etched through opening 1203 to form an opening 1301 according to
one embodiment. FIG. 13B is a view 1310 similar to FIG. 12A after
the insulating layer 1201 and insulating layer 1001 are selectively
etched through opening 1203 to form opening 1301 according to one
embodiment.
[0109] FIG. 13B is different from FIG. 12A in that FIG. 13B shows a
cut through opening 1301 along X axis 121 and Y axis 122. As shown
in FIGS. 13A and 13B, opening 1301 includes a via portion 1302 and
a trench portion 1303. As shown in FIGS. 13A and 13B, via portion
1302 of the opening 1301 is limited along Y axis 122 by insulating
layer 701. Via portion 1302 of the opening 1301 is self-aligned
along Y axis to one of the conductive lines 201. As shown in FIGS.
13A and 13B, trench portion 1303 is limited along X axis 121 by the
features of the hard mask layer 1101 that extend along Y axis 122.
In one embodiment, insulating layer 1001 is selectively etched
relative to the insulating layer 701 to form opening 1301.
[0110] In one embodiment, insulating layer 1201 is selectively
etched relative to the insulating layer 701 to form opening 1301.
As shown in FIGS. 13A and 13B, mask layer 1202 and insulating layer
1201 are removed. In one embodiment, mask layer 1202 is removed
using one or more of the mask layer removal techniques known to one
of ordinary skill in the art of microelectronic device
manufacturing. In one embodiment, insulating layer 1201 is removed
using one or more of the etching techniques known to one of
ordinary skill in the art of microelectronic device
manufacturing.
[0111] FIG. 14A is a view 1400 similar to FIG. 10A, after a mask
layer 1402 is deposited on a hard mask layer 1401 on the exposed
insulating layer 701 and insulating layer 1001 according to one
embodiment. FIG. 14B is a top view 1410 of the electronic device
structure depicted in FIG. 14A. As shown in FIG. 14A, a portion of
the insulating layer 1001 is removed to even out top portions of
the insulating layer 701 with top portions of the insulating layer
1001. As shown in FIGS. 14A and 14B, mask layer 1402 has an opening
1403 to expose hard mask layer 1401.
[0112] In one embodiment, the portion of the insulating layer 1001
is removed using a CMP technique known to one of ordinary skill in
the art of microelectronic device manufacturing. In one embodiment,
a portion of the insulating layer 1001 is etched back to expose the
top portion of the insulating layer 701. In another embodiment, a
portion of the insulating layer 701 is etched back to a
predetermined depth to expose upper portions of the sidewalls and
top portions of the insulating layer 1001 in the trenches 901. In
one embodiment, the portion of the insulating layer 701 is etched
back using one or more of the dry and wet etching techniques known
to one of ordinary skill in the art of microelectronic device
manufacturing.
[0113] In one embodiment, mask layer 1402 includes a photoresist
layer. In one embodiment, mask layer 1402 includes one or more hard
mask layers. In one embodiment, mask layer 1402 is a tri-layer mask
stack, e.g., a 193 nm immersion (193i) or EUV resist mask on a
middle layer (ML) (e.g., a silicon containing organic layer or a
metal containing dielectric layer) on a bottom anti-reflective
coating (BARC) layer on a silicon oxide hard mask. In one
embodiment, the hard mask layer 1401 is a metallization layer hard
mask to pattern the conductive lines of the next metallization
layer. In one embodiment, hard mask layer 1401 includes a titanium
nitride (TiN) layer, a tungsten carbide (WC) layer, a tungsten
bromide carbide (WBC) layer, a carbon hard mask layer, a metal
oxide hard mask layer, a metal nitride hard mask layer, a silicon
nitride hard mask layer, a silicon oxide hard mask layer, a carbide
hard mask layer, other hard mask layer or any combination thereof.
In one embodiment, hard mask layer 1401 represents one of the hard
mask layers described above.
[0114] In one embodiment, the insulating layer 701 and the
insulating layer 1001 are patterned and etched using hard mask 1401
to form trenches using one or more patterning and etching
techniques known to one or ordinary skill in the art of
microelectronic device manufacturing. In one embodiment, the size
of trenches in the insulating layer 701 and insulating layer 1001
is determined by the size of conductive lines formed later on in a
process.
[0115] In one embodiment, the mask layer 1402 is deposited using
one or more of the mask deposition techniques known to one of
ordinary skill in the art of microelectronic device manufacturing.
In one embodiment, hard mask layer 1401 is deposited using one or
more hard mask layer deposition techniques, such as but not limited
to a CVD, PVD, MBE, MOCVD, spin-on, or other hard mask deposition
known to one of ordinary skill in the art of microelectronic device
manufacturing. In one embodiment, the opening 1403 is formed using
one or more of the patterning and etching techniques known to one
of ordinary skill in the art of microelectronic device
manufacturing.
[0116] FIG. 15A is a view 1500 similar to FIG. 14A, after portions
of the hard mask layer 1401, insulating layer 701 and insulating
layer 1001 are removed through opening 1403 to form an opening 1501
in insulating layer 701 according to one embodiment. FIG. 15B is a
top view 1510 of the electronic device structure depicted in FIG.
15A. In one embodiment, opening 1501 is a trench opening for a via.
As shown in FIGS. 15A and 15B, opening 1501 includes a bottom 1505
that includes a portion 1502 of the insulating layer 1001 between
portions 1503 and 1504 of the insulating layer 701. As shown in
FIGS. 15A and 15B, opening 1501 includes opposing sidewalls 1506
that include portions of the insulating layer 701. In one
embodiment, each sidewall 1506 is substantially orthogonal to
bottom 1505. In another embodiment, each sidewall 1506 is slanted
relative to bottom 1505 at an angle other than 90 degrees, so that
an upper portion of the opening 1501 is greater than a lower
portion of the opening 1501.
[0117] In one embodiment, opening 1501 having slanted sidewalls is
formed using an angled non-selective etch. In one embodiment, hard
mask layer 1401 is removed using one or more of wet etching, dry
etching, or a combination thereof techniques known to one of
ordinary skill in the art of microelectronic device manufacturing.
In one embodiment, insulating layer 701 and insulating layer 1001
are removed using a non-selective etch in a trench first dual
damascene process. In one embodiment, insulating layer 701 and
insulating layer 1001 are etched down to the depth that is
determined by time. In another embodiment, insulating layer 701 and
insulating layer 1001 are etched non-selectively down to an etch
stop layer (not shown). In one embodiment, insulating layer 701 and
insulating layer 1001 are non-selectively etched using one or more
of wet etching, dry etching, or a combination thereof techniques
known to one of ordinary skill in the art of electronic device
manufacturing.
[0118] FIG. 16A is a view 1600 similar to FIG. 15A, after a fully
self-aligned opening 1601 is formed in insulating layer 701
according to one embodiment. FIG. 16B is a top view 1610 of the
electronic device structure depicted in FIG. 16A. As shown in FIGS.
16A and 16B, mask layer 1402 is removed. Mask layer 1402 can be
removed using one of the mask layer removal techniques known to one
of ordinary skill in the art of microelectronic device
manufacturing. A patterned mask layer 1607 is formed on hard mask
layer 1401. As shown in FIG. 16B, patterned mask layer 1607 is
deposited on the hard mask layer 1401 and into opening 1501.
Patterned mask layer 1607 has an opening 1604. Patterned mask layer
1607 can be formed using one or more of the mask layer depositing,
patterning and etching techniques known to one of ordinary skill in
the art of microelectronic device manufacturing.
[0119] Fully self-aligned opening 1601 is formed through mask
opening 1604. Fully self-aligned opening 1601 includes a trench
opening 1603 and a via opening 1602, as shown in FIGS. 16A and 16B.
Via opening 1602 is underneath trench opening 1603. In one
embodiment, trench opening 1603 is the part of the that is exposed
through opening 1604.
[0120] In one embodiment, via opening 1602 is formed by selectively
etching insulating layer 1001 relative to the insulating layer 701
through mask opening 1604 and trench opening 1603. In one
embodiment, trench opening 1603 extends along Y axis 122. As shown
in FIG. 16B, trench opening 1603 is greater along Y axis 122 than
along X axis 121.
[0121] In one embodiment, trench opening 1603 of the opening 1601
is self-aligned along X-axis 121 between the features of the hard
mask layer 1401 that are used to pattern the upper metallization
layer conductive lines that extend along Y axis 122 (not shown).
The via opening 1602 of the opening 1601 is self-aligned along
Y-axis 122 by the insulating layer 701 that is left intact by
selectively etching the portion 1502 of the insulating layer 1001
relative to the insulating layer 701. This provides an advantage as
the size of the trench opening 1603 does not need to be limited to
the size of the cross-section between the conductive line 1608 and
one of the conductive lines of the upper metallization layer that
provides more flexibility for the lithography equipment. As the
portion 1502 is selectively removed relative to the insulating
layer 701, the size of the trench opening increases.
[0122] As shown in FIGS. 15A and 15B, the portion 1502 is
self-aligned with a conductive line 1608 that is one of the lower
metallization layer conductive lines 201. That is, the opening 1601
is self-aligned along both X and Y axes.
[0123] FIG. 16A is different from FIG. 15A in that FIG. 16A
illustrates trench opening 1603 having slanted sidewalls 1605. Each
sidewall 1605 is at an angle other than 90 degrees to the top
surface of the substrate 101, so that an upper portion of the
trench opening 1603 is greater than a lower portion of the trench
opening 1603. In another embodiment, the sidewalls 1605 are
substantially orthogonal to the top surface of the substrate
101.
[0124] In one embodiment, mask layer 1607 includes a photoresist
layer. In one embodiment, mask layer 1607 includes one or more hard
mask layers. In one embodiment, mask layer 1607 is tri-layer mask
stack, e.g., a 193i or EUV resist mask on a ML (e.g., a silicon
containing organic layer or a metal containing dielectric layer) on
a BARC layer on a silicon oxide hard mask. As shown in FIGS. 16A
and 16B, via opening 1602 exposes a portion 1606 of the liner 301
on conductive line 1608. In another embodiment, when the liner 301
is removed, the via opening 1602 exposes conductive line 1608.
[0125] FIG. 17A is a view 1700 similar to FIG. 16A, after an upper
metallization layer My comprising conductive lines extending along
Y axis 122 is formed according to one embodiment. FIG. 17B is a top
view 1710 of the electronic device structure depicted in FIG. 17A.
FIG. 17A is a cross-sectional view of FIG. 17B along an axis C-C'.
As shown in FIG. 17A, mask layer 1402 and hard mask layer 1401 are
removed. In one embodiment, each of the mask layer 1402 and hard
mask layer 1401 is removed using one or more of the hard mask layer
removal techniques know in one of ordinary skill in the art of
microelectronic device manufacturing.
[0126] An upper metallization layer My includes a set of conductive
lines 1701 that extend on portions of insulating layer 1001 and
portions insulating layer 701. As shown in FIG. 17B, the portions
of the insulating layer 1001 are between the portions of the
insulating layer 701. Conductive lines 1701 extend along Y axis
122. A fully self-aligned via 1712 includes a trench portion 1702
and a via portion 1703. Via portion 1703 is underneath trench
portion 1702. The fully self-aligned via 1712 is between the lower
metallization layer comprising conductive lines 201 that extend
along X axis 121 and the upper metallization layer comprising
conductive lines 1701. As shown in FIGS. 17A and 17B, the via
portion 1703 is on liner 301 on conductive line 1608. As shown in
FIGS. 17A and 17B, the via portion 1703 of the via 1712 is
self-aligned along the Y axis 122 to conductive line 1608 that is
one of the conductive lines 201. The via portion 1703 of the via
1712 is self-aligned along the X axis (direction) 121 to a
conductive line 1711 that is one of the conductive lines 1701. In
one embodiment, when liner 301 is removed, the via portion 1703 is
directly on conductive line 1608. As shown in FIGS. 17A and 17B,
the via portion 1703 is a part of the conductive line 1711. As
shown in FIGS. 17A and 17B, the size of the via portion 1703 is
determined by the size of the cross-section between the conductive
line 1608 and conductive line 1711.
[0127] In one embodiment, forming the conductive lines 1701 and via
1712 involves filling the trenches in the insulating layer and the
opening 1601 with a layer of conductive material. In one
embodiment, a base layer (not shown) is first deposited on the
internal sidewalls and bottom of the trenches and the opening 1601,
and then the conductive layer is deposited on the base layer. In
one embodiment, the base layer includes a conductive seed layer
(not shown) deposited on a conductive barrier layer (not shown).
The seed layer can include copper, and the conductive barrier layer
can include aluminum, titanium, tantalum, tantalum nitride, and the
like metals. The conductive barrier layer can be used to prevent
diffusion of the conductive material from the seed layer, e.g.,
copper, into the insulating layer. Additionally, the conductive
barrier layer can be used to provide adhesion for the seed layer
(e.g, copper).
[0128] In one embodiment, to form the base layer, the conductive
barrier layer is deposited onto the sidewalls and bottom of the
trenches, and then the seed layer is deposited on the conductive
barrier layer. In another embodiment, the conductive base layer
includes the seed layer that is directly deposited onto the
sidewalls and bottom of the trenches. Each of the conductive
barrier layer and seed layer may be deposited using any thin film
deposition technique known to one of ordinary skill in the art of
semiconductor manufacturing, e.g., sputtering, blanket deposition,
and the like. In one embodiment, each of the conductive barrier
layer and the seed layer has the thickness in an approximate range
from about 1 nm to about 100 nm. In one embodiment, the barrier
layer may be a thin dielectric that has been etched to establish
conductivity to the metal layer below. In one embodiment, the
barrier layer may be omitted altogether and appropriate doping of
the copper line may be used to make a "self-forming barrier".
[0129] In one embodiment, the conductive layer e.g., copper, is
deposited onto the seed layer of base later of copper, by an
electroplating process. In one embodiment, the conductive layer is
deposited into the trenches using a damascene process known to one
of ordinary skill in the art of microelectronic device
manufacturing. In one embodiment, the conductive layer is deposited
onto the seed layer in the trenches and in the opening 1601 using a
selective deposition technique, such as but not limited to
electroplating, electroless, a CVD, PVD, MBE, MOCVD, ALD, spin-on,
or other deposition techniques known to one of ordinary skill in
the art of microelectronic device manufacturing.
[0130] In one embodiment, the choice of a material for conductive
layer for the conductive lines 1701 and via 1712 determines the
choice of a material for the seed layer. For example, if the
material for the conductive lines 1701 and via 1712 includes
copper, the material for the seed layer also includes copper. In
one embodiment, the conductive lines 1701 and via 1712 include a
metal, for example, copper (Cu), ruthenium (Ru), nickel (Ni),
cobalt (Co), chromium (Cr), iron (Fe), manganese (Mn), titanium
(Ti), aluminum (Al), hafnium (Hf), tantalum (Ta), tungsten (W),
vanadium (V), molybdenum (Mo), palladium (Pd), gold (Au), silver
(Ag), platinum (Pt), indium (In), tin (Sn), lead (Pb), antimony
(Sb), bismuth (Bi), zinc (Zn), cadmium (Cd), or any combination
thereof.
[0131] In alternative embodiments, examples of the conductive
materials that may be used for the conductive lines 1701 and via
1712 are, but not limited to, metals, e.g., copper, tantalum,
tungsten, ruthenium, titanium, hafnium, zirconium, aluminum,
silver, tin, lead, metal alloys, metal carbides, e.g., hafnium
carbide, zirconium carbide, titanium carbide, tantalum carbide,
aluminum carbide, other conductive materials, or any combination
thereof.
[0132] In one embodiment, portions of the conductive layer and the
base layer are removed to even out top portions of the conductive
lines 1701 with top portions of the insulating layer 701 and
insulating layer 1001 using a chemical-mechanical polishing ("CMP")
technique known to one of ordinary skill in the art of
microelectronic device manufacturing.
[0133] In one non-limiting example, the thickness of the conductive
lines 1701 is in an approximate range from about 15 nm to about
1000 nm. In one non-limiting example, the thickness of the
conductive lines 1701 is from about 20 nm to about 200 nm. In one
non-limiting example, the width of the conductive lines 1701 is in
an approximate range from about 5 nm to about 500 nm. In one
non-limiting example, the spacing (pitch) between the conductive
lines 1701 is from about 2 nm to about 500 nm. In more specific
non-limiting example, the spacing (pitch) between the conductive
lines 1701 is from about 5 nm to about 50 nm.
[0134] FIGS. 18 through 22 (including both A and B designations)
illustrate another embodiment of the disclosure. FIG. 18A is a view
1800 similar to FIG. 10A, after a mask layer 1802 is deposited on a
hard mask layer 1801 on the insulating layer 1001 according to one
embodiment. FIG. 18B is a top view 1810 of the electronic device
structure depicted in FIG. 18A. As shown in FIGS. 18A and 18B, mask
layer 1802 has an opening 1803 to expose hard mask layer 1801.
[0135] In one embodiment, mask layer 1802 includes a photoresist
layer. In one embodiment, mask layer 1802 includes one or more hard
mask layers. In one embodiment, mask layer 1802 is a tri-layer mask
stack, e.g., a 193 nm immersion (193i) or EUV resist mask on a
middle layer (ML) (e.g., a silicon containing organic layer or a
metal containing dielectric layer) on a bottom anti-reflective
coating (BARC) layer on a silicon oxide hard mask. In one
embodiment, the hard mask layer 1801 is a metallization layer hard
mask to pattern the conductive lines of the next metallization
layer. In one embodiment, hard mask layer 1801 includes a titanium
nitride (TiN) layer, a tungsten carbide (WC) layer, a tungsten
bromide carbide (WBC) layer, a carbon hard mask layer, a metal
oxide hard mask layer, a metal nitride hard mask layer, a silicon
nitride hard mask layer, a silicon oxide hard mask layer, a carbide
hard mask layer, other hard mask layer or any combination thereof.
In one embodiment, hard mask layer 1801 represents one of the hard
mask layers described above.
[0136] In one embodiment, the mask layer 1802 is deposited using
one or more of the mask deposition techniques known to one of
ordinary skill in the art of microelectronic device manufacturing.
In one embodiment, hard mask layer 1801 is deposited using one or
more hard mask layer deposition techniques, such as but not limited
to a CVD, PVD, MBE, MOCVD, spin-on, or other hard mask deposition
known to one of ordinary skill in the art of microelectronic device
manufacturing. In one embodiment, the opening 1803 is formed using
one or more of the patterning and etching techniques known to one
of ordinary skill in the art of microelectronic device
manufacturing.
[0137] FIG. 19A is a view 1900 similar to FIG. 18A, after portions
of the hard mask layer 1801 and insulating layer 1001 are removed
through opening 1803 to form an opening 1901 in insulating layer
1001 according to one embodiment. FIG. 19B is a top view 1910 of
the electronic device structure depicted in FIG. 19A. In one
embodiment, opening 1901 is a trench opening for a via. As shown in
FIGS. 19A and 19B, opening 1901 includes a bottom 1905 that
includes a portion 1902 of the insulating layer 1001 between
portions 1903 and 1904 of the insulating layer 701. As shown in
FIGS. 19A and 19B, opening 1901 includes opposing sidewalls 1906
that include portions of the insulating layer 1001. In one
embodiment, each sidewall 1906 is substantially orthogonal to
bottom 1905. In another embodiment, each sidewall 1906 is slanted
relative to bottom 1905 at an angle other than 90 degrees, so that
an upper portion of the opening 1901 is greater than a lower
portion of the opening 1901.
[0138] In one embodiment, opening 1901 having slanted sidewalls is
formed using an angled non-selective etch. In one embodiment, hard
mask layer 1801 is removed using one or more of wet etching, dry
etching, or a combination thereof techniques known to one of
ordinary skill in the art of microelectronic device manufacturing.
In one embodiment, insulating layer 1001 is removed using a
non-selective etch in a trench first dual damascene process. In one
embodiment, insulating layer 1001 is etched down to the depth that
is determined by time. In another embodiment, insulating layer 1001
is etched non-selectively down to an etch stop layer (not shown).
In one embodiment, insulating layer 1001 is non-selectively etched
using one or more of wet etching, dry etching, or a combination
thereof techniques known to one of ordinary skill in the art of
electronic device manufacturing.
[0139] FIG. 20A is a view 2000 similar to FIG. 19A, after mask
layer 1802 is removed, planarization filling layer 2001 is formed
and mask layer 2002 with a fully self-aligned opening 2003 is
formed according to one embodiment. FIG. 20B is a top view 2010 of
the electronic device structure depicted in FIG. 20A. As shown in
FIGS. 20A and 20B, mask layer 1802 is removed. Mask layer 1802 can
be removed using one of the mask layer removal techniques known to
one of ordinary skill in the art of microelectronic device
manufacturing. A planarization filling layer 2001 is formed in
opening 1901 onto the tops of exposed insulating layer 701 and
insulating layer 1001. The planarization filling layer 2001
illustrated is formed so that an overburden 2004 is formed on hard
mask 1801. In some embodiments, the planarization filling layer
2001 is formed to be substantially coplanar with the hard mask
1801. In some embodiments, the planarization filling layer 2001 is
planarized, for example, by a CMP process. The planarization
filling layer 2001 can be any suitable material including, but not
limited to, BARC (Bottom Anti-Reflective Coating) layer (e.g.,
spin-on polymers containing C and H, or Si), DARC (Dielectric
Anti-Reflective Coating) layer or an OPL (Organic Planarization
Layer). The planarization filling layer 2001 of some embodiments is
deposited by CVD or ALD. In some embodiments, the planarization
filling layer 2001 comprises one or more atoms of Si, O, N, C or
H.
[0140] A patterned mask layer 2002 is formed on hard mask layer
1801. As shown in FIG. 20B, patterned mask layer 2002 is deposited
on the planarization filling layer 2001. Patterned mask layer 2002
has an opening 2003. Patterned mask layer 2002 can be formed using
one or more of the mask layer depositing, patterning and etching
techniques known to one of ordinary skill in the art of
microelectronic device manufacturing.
[0141] In one embodiment, mask layer 2007 includes a photoresist
layer. In one embodiment, mask layer 2007 includes one or more hard
mask layers. In one embodiment, mask layer 2007 is tri-layer mask
stack, e.g., a 193i or EUV resist mask on a ML (e.g., a silicon
containing organic layer or a metal containing dielectric layer) on
a BARC layer on a silicon oxide hard mask.
[0142] FIG. 21A is a view 2100 similar to FIG. 20A, after removing
the planarization filling layer 2001 and insulating layer 1001
through opening 2003. The embodiment illustrated has the patterned
hard mask layer 2002 and planarization filling layer 2001 removed
from hard mask 1801. A fully self-aligned opening 2101 is formed
through mask opening 2003. Fully self-aligned opening 2101 includes
a trench opening 2103 and a via opening 2102, as shown in FIGS. 21A
and 21B. Via opening 2102 is underneath trench opening 2103.
[0143] In one or more embodiments, via opening 2102 is formed by
selectively etching insulating layer 1001 relative to the
insulating layer 701 through mask opening 2003 and trench opening
2103. In one embodiment, trench opening 2103 extends along Y axis
122. As shown in FIG. 21 B, trench opening 2103 is greater along Y
axis 122 than along X axis 121.
[0144] In one embodiment, trench opening 2103 of the opening 2101
is self-aligned along X-axis between the features of the hard mask
layer 1801 that are used to pattern the upper metallization layer
conductive lines that extend along Y axis 122 (not shown). The via
opening 2102 of the opening 2101 is self-aligned along Y-axis 122
by the insulating layer 701 that is left intact by selectively
etching the portion 1902 of the insulating layer 1001 relative to
the insulating layer 701. This provides an advantage as the size of
the trench opening 2103 does not need to be limited to the size of
the cross-section between the conductive line 2108 and one of the
conductive lines of the upper metallization layer that provides
more flexibility for the lithography equipment. As the portion 1902
is selectively removed relative to the insulating layer 701, the
size of the trench opening increases.
[0145] As shown in FIGS. 19A and 19B, the portion 1902 is
self-aligned with a conductive line 2108 that is one of the lower
metallization layer conductive lines 201. That is, the opening 2101
is self-aligned along both X and Y axes.
[0146] FIG. 21A illustrates trench opening 2103 having sidewalls
2105 that are substantially orthogonal to the top surface of the
substrate 101. In some embodiments, each sidewall 2105 is at an
angle other than 90 degrees to the top surface of the substrate
101, so that an upper portion of the trench opening 2103 is greater
than a lower portion of the trench opening 2103.
[0147] As shown in FIGS. 21A and 21B, via opening 2102 exposes a
portion 2106 of the liner 301 on conductive line 2108. In another
embodiment, when the liner 301 is removed, the via opening 2102
exposes conductive line 2108.
[0148] FIG. 22A is a view 2200 similar to FIG. 21A, after an upper
metallization layer My comprising conductive lines extending along
Y axis 122 is formed according to one embodiment. FIG. 22B is a top
view 2210 of the electronic device structure depicted in FIG. 22A.
FIG. 22A is a cross-sectional view of FIG. 22B taken along an axis
C-C'. As shown in FIG. 22A, hard mask layer 1801 is removed. In one
embodiment, hard mask layer 1801 is removed using one or more of
the hard mask layer removal techniques know in one of ordinary
skill in the art of microelectronic device manufacturing.
[0149] An upper metallization layer My includes a set of conductive
lines 2201 that extend on portions of insulating layer 701. In the
embodiment illustrated in FIG. 22A, the conductive lines 2201 are
filled to be co-planar with the top of insultaing layer 1001. In
some embodiments, the conductive lines 2201 extend above the top
surface of insulating layer 1001, similar to that shown in FIG.
17A.
[0150] As shown in FIG. 22B, the portions of the insulating layer
1001 are between the portions of the insulating layer 701.
Conductive lines 2201 extend along Y axis 122. A fully self-aligned
via 2212 includes a trench portion 2202 and a via portion 2203. Via
portion 2203 is underneath trench portion 2202. The fully
self-aligned via 2212 is between the lower metallization layer
comprising conductive lines 201 that extend along X axis 121 and
the upper metallization layer comprising conductive lines 2201. As
shown in FIGS. 22A and 22B, the via portion 2203 is on liner 301 on
conductive line 2108. As shown in FIGS. 22A and 22B, the via
portion 2203 of the via 2212 is self-aligned along the Y axis 122
to conductive line 2108 that is one of the conductive lines 201.
The trench portion 2203 of the via 2212 is self-aligned along the X
axis 121. In one embodiment, when liner 301 is removed, the via
portion 2203 is directly on conductive line 2108.
[0151] In one embodiment, forming the conductive lines 2201 and via
2212 involves filling the trenches in the insulating layer and the
opening 2101 with a layer of conductive material. In one
embodiment, a base layer (not shown) is first deposited on the
internal sidewalls and bottom of the trenches and the opening 2101,
and then the conductive layer is deposited on the base layer. In
one embodiment, the base layer includes a conductive seed layer
(not shown) deposited on a conductive barrier layer (not shown).
The seed layer can include copper, and the conductive barrier layer
can include aluminum, titanium, tantalum, tantalum nitride, and the
like metals. The conductive barrier layer can be used to prevent
diffusion of the conductive material from the seed layer, e.g.,
copper, into the insulating layer. Additionally, the conductive
barrier layer can be used to provide adhesion for the seed layer
(e.g, copper).
[0152] In one embodiment, to form the base layer, the conductive
barrier layer is deposited onto the sidewalls and bottom of the
trenches, and then the seed layer is deposited on the conductive
barrier layer. In another embodiment, the conductive base layer
includes the seed layer that is directly deposited onto the
sidewalls and bottom of the trenches. Each of the conductive
barrier layer and seed layer may be deposited using any thin film
deposition technique known to one of ordinary skill in the art of
semiconductor manufacturing, e.g., sputtering, blanket deposition,
and the like. In one embodiment, each of the conductive barrier
layer and the seed layer has the thickness in an approximate range
from about 1 nm to about 100 nm. In one embodiment, the barrier
layer may be a thin dielectric that has been etched to establish
conductivity to the metal layer below. In one embodiment, the
barrier layer may be omitted altogether and appropriate doping of
the copper line may be used to make a "self-forming barrier".
[0153] In one embodiment, the conductive layer e.g., copper, is
deposited onto the seed layer of base later of copper, by an
electroplating process. In one embodiment, the conductive layer is
deposited into the trenches using a damascene process known to one
of ordinary skill in the art of microelectronic device
manufacturing. In one embodiment, the conductive layer is deposited
onto the seed layer in the trenches and in the opening 1601 using a
selective deposition technique, such as but not limited to
electroplating, electroless, a CVD, PVD, MBE, MOCVD, ALD, spin-on,
or other deposition techniques known to one of ordinary skill in
the art of microelectronic device manufacturing.
[0154] In one embodiment, the choice of a material for conductive
layer for the conductive lines 2201 and via 2212 determines the
choice of a material for the seed layer. For example, if the
material for the conductive lines 2201 and via 2212 includes
copper, the material for the seed layer also includes copper. In
one embodiment, the conductive lines 2201 and via 2212 include a
metal, for example, copper (Cu), ruthenium (Ru), nickel (Ni),
cobalt (Co), chromium (Cr), iron (Fe), manganese (Mn), titanium
(Ti), aluminum (Al), hafnium (Hf), tantalum (Ta), tungsten (W),
vanadium (V), molybdenum (Mo), palladium (Pd), gold (Au), silver
(Ag), platinum (Pt), indium (In), tin (Sn), lead (Pb), antimony
(Sb), bismuth (Bi), zinc (Zn), cadmium (Cd), or any combination
thereof.
[0155] In alternative embodiments, examples of the conductive
materials that may be used for the conductive lines 2201 and via
2212 are, but not limited to, metals, e.g., copper, tantalum,
tungsten, ruthenium, titanium, hafnium, zirconium, aluminum,
silver, tin, lead, metal alloys, metal carbides, e.g., hafnium
carbide, zirconium carbide, titanium carbide, tantalum carbide,
aluminum carbide, other conductive materials, or any combination
thereof.
[0156] In one embodiment, portions of the conductive layer and the
base layer are removed to even out top portions of the conductive
lines 2201 with top portions of the insulating layer 1001 using a
chemical-mechanical polishing ("CMP") technique known to one of
ordinary skill in the art of microelectronic device
manufacturing.
[0157] In one non-limiting example, the thickness of the conductive
lines 2201 is in an approximate range from about 15 nm to about
1000 nm. In one non-limiting example, the thickness of the
conductive lines 2201 is from about 20 nm to about 200 nm. In one
non-limiting example, the width of the conductive lines 2201 is in
an approximate range from about 5 nm to about 500 nm. In one
non-limiting example, the spacing (pitch) between the conductive
lines 2201 is from about 2 nm to about 500 nm. In more specific
non-limiting example, the spacing (pitch) between the conductive
lines 2201 is from about 5 nm to about 50 nm.
[0158] In an embodiment, the upper metallization layer My is
configured to connect to other metallization layers (not shown). In
an embodiment, the metallization layer My is configures to provide
electrical contact to electronic devices, e.g., transistors,
memories, capacitors, resistors, optoelectronic devices, switches,
and any other active and passive electronic devices that are
separated by an electrically insulating layer, for example, an
interlayer dielectric, a trench insulation layer, or any other
insulating layer known to one or ordinary skill in the art of
electronic device manufacturing.
[0159] FIG. 23 shows a block diagram of a plasma system to perform
at least some of the operations to provide a fully self-aligned via
according to one embodiment. As shown in FIG. 23, system 2300 has a
processing chamber 2301. A movable pedestal 2302 to hold an
electronic device structure 2303 is placed in processing chamber
2301. Pedestal 2302 comprises an electrostatic chuck ("ESC"), a DC
electrode embedded into the ESC, and a cooling/heating base. In an
embodiment, pedestal 2301 acts as moving cathode. In an embodiment,
the ESC comprises an Al.sub.2O.sub.3 material, Y.sub.2O.sub.3 or
other ceramic materials known to one of ordinary skill of
electronic device manufacturing. A DC power supply 2304 is
connected to the DC electrode of the pedestal 2302.
[0160] As shown in FIG. 23, an electronic device structure 2303 is
loaded through an opening 2308 and placed on the pedestal 2302. The
electronic device structure 2303 represents one of the electronic
device structures described above. System 2300 comprises an inlet
to input one or more process gases 2312 through a mass flow
controller 2311 to a plasma source 2313. A plasma source 2313
comprising a showerhead 2314 is coupled to the processing chamber
2301 to receive one or more gases 2312 to generate plasma. Plasma
source 2313 is coupled to a RF source power 2310. Plasma source
2313 through showerhead 2314 generates a plasma 2315 in processing
chamber 2301 from one or more process gases 2312 using a high
frequency electric field. Plasma 2315 comprises plasma particles,
such as ions, electrons, radicals, or any combination thereof. In
an embodiment, power source 2310 supplies power from about 50 W to
about 3000 W at a frequency from about 400 kHz to about 162 MHz to
generate plasma 2315.
[0161] A plasma bias power 2305 is coupled to the pedestal 2302
(e.g., cathode) via a RF match 2307 to energize the plasma. In an
embodiment, the plasma bias power 2305 provides a bias power that
is not greater than 1000 W at a frequency between about 2 MHz to 60
MHz, and in a particular embodiment at about 13 MHz. A plasma bias
power 2306 may also be provided, for example, to provide another
bias power that is not greater than 1000 W at a frequency from
about 400 kHz to about 60 MHz, and in a particular embodiment, at
about 60 MHz. Plasma bias power 2306 and bias power 2305 are
connected to RF match 2307 to provide a dual frequency bias power.
In an embodiment, a total bias power applied to the pedestal 2302
is from about 10 W to about 3000 W.
[0162] As shown in FIG. 23, a pressure control system 2309 provides
a pressure to processing chamber 2301. As shown in FIG. 23, chamber
2301 has one or more exhaust outlets 2316 to evacuate volatile
products produced during processing in the chamber. In an
embodiment, the plasma system 2300 is an inductively coupled plasma
(ICP) system. In an embodiment, the plasma system 2300 is a
capacitively coupled plasma (CCP) system.
[0163] A control system 2317 is coupled to the chamber 2301. The
control system 2317 comprises a processor 2318, a temperature
controller 2319 coupled to the processor 2318, a memory 2320
coupled to the processor 2318, and input/output devices 2321
coupled to the processor 2318 to form fully self-aligned via as
described herein.
[0164] In one embodiment, the processor 2318 has a configuration to
control recessing first conductive lines on a first insulating
layer on a substrate, the first conductive lines extending along a
first direction on the first insulating layer. The processor 2318
has a configuration to control depositing a liner on the recessed
first conductive lines. The processor has a configuration to
control selectively growing a seed layer on the recessed first
conductive lines. The processor 2318 has a configuration to control
forming pillars using the selectively grown seed layer. The
processor 2318 has a configuration to control depositing a second
insulating layer between the pillars. The processor 2318 has a
configuration to control removing the pillars to form trenches in
the second insulating layer. The processor 2318 has a configuration
to control depositing a third insulating layer into the trenches in
the second insulating layer. The processor 2318 has a configuration
to control selectively etching the third insulating layer relative
to the second insulating layer to form a fully self-aligned via
opening down to one of the first conductive lines. The processor
2318 has a configuration to control depositing a conductive layer
into the self-aligned via opening, as described above.
[0165] The control system 2317 is configured to perform at least
some of the methods as described herein and may be either software
or hardware or a combination of both. The plasma system 2300 may be
any type of high performance processing plasma systems known in the
art, such as but not limited to, an etcher, a cleaner, a furnace,
or any other plasma system to manufacture electronic devices.
[0166] In the foregoing specification, embodiments of the
disclosure have been described with reference to specific exemplary
embodiments thereof. It will be evident that various modifications
may be made thereto without departing from the broader spirit and
scope of the embodiments of the disclosure as set forth in the
following claims. The specification and drawings are, accordingly,
to be regarded in an illustrative sense rather than a restrictive
sense.
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