U.S. patent application number 16/156325 was filed with the patent office on 2020-04-16 for self-aligned gate cut method and multilayer gate-cut pillar structure.
The applicant listed for this patent is GLOBALFOUNDRIES Inc.. Invention is credited to Youngtag Woo, Ruilong Xie, Hui Zang.
Application Number | 20200119163 16/156325 |
Document ID | / |
Family ID | 70159146 |
Filed Date | 2020-04-16 |
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United States Patent
Application |
20200119163 |
Kind Code |
A1 |
Xie; Ruilong ; et
al. |
April 16, 2020 |
SELF-ALIGNED GATE CUT METHOD AND MULTILAYER GATE-CUT PILLAR
STRUCTURE
Abstract
One illustrative method disclosed herein includes forming a
sacrificial gate structure and a gate-cut structure within the
sacrificial gate structure at a location positioned above the
isolation material, the gate-cut structure having an upper portion
and a lower portion, and forming a replacement gate cavity by
removing the sacrificial gate structure and the lower portion of
the gate-cut structure. The method further includes forming a final
gate structure that includes forming a gate insulation layer of the
final gate structure on all exposed surfaces of the upper portion
of the gate-cut structure, removing the upper portion of the
gate-cut structure, removing the exposed portion of the final gate
structure to define a gate-cut opening that separates the final
gate structure into the first and second final gate structures, and
forming a gate separation structure in the gate-cut opening.
Inventors: |
Xie; Ruilong; (Niskayuna,
NY) ; Woo; Youngtag; (San Ramon, CA) ; Zang;
Hui; (Guilderland, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GLOBALFOUNDRIES Inc. |
Grand Cayman |
|
KY |
|
|
Family ID: |
70159146 |
Appl. No.: |
16/156325 |
Filed: |
October 10, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/31144 20130101;
H01L 21/28194 20130101; H01L 29/517 20130101; H01L 29/4958
20130101; H01L 21/31053 20130101; H01L 21/28079 20130101; H01L
21/823437 20130101; H01L 21/28088 20130101; H01L 29/4966 20130101;
H01L 21/823481 20130101; H01L 29/66545 20130101; H01L 21/02181
20130101; H01L 21/02271 20130101; H01L 21/823431 20130101; H01L
29/6656 20130101; H01L 21/32139 20130101; H01L 21/0273
20130101 |
International
Class: |
H01L 29/66 20060101
H01L029/66; H01L 21/8234 20060101 H01L021/8234; H01L 21/311
20060101 H01L021/311; H01L 29/51 20060101 H01L029/51; H01L 29/49
20060101 H01L029/49; H01L 21/28 20060101 H01L021/28 |
Claims
1. A method of cutting a final gate structure into first and second
final gate structures for first and second transistor devices
laterally separated by isolation material, comprising: forming a
sacrificial gate structure and a gate-cut structure within said
sacrificial gate structure at a position located above said
isolation material, said gate-cut structure comprising an upper
portion and a lower portion; forming a replacement gate cavity by
removing said sacrificial gate structure and said lower portion of
said gate-cut structure, said replacement gate cavity comprising a
space vertically below said upper portion of said gate-cut
structure; forming a final gate structure in said replacement gate
cavity and in said space under said upper portion of said gate-cut
structure, wherein forming said final gate structure comprises
forming a gate insulation layer of said final gate structure on all
exposed surfaces of said upper portion of said gate-cut structure;
removing said upper portion of said gate-cut structure and an
underlying portion of said gate insulation layer to define an
opening that exposes a portion of said final gate structure;
removing said exposed portion of said final gate structure to
define a gate-cut opening that separates said final gate structure
into said first and second final gate structures; and forming a
gate separation structure in said gate-cut opening, said gate
separation structure comprising an insulating material.
2. The method of claim 1, wherein, prior to removing said upper
portion of said gate-cut structure and said underlying portion of
said gate insulation layer, the method comprises removing a portion
of said gate insulation layer positioned on an upper surface of
said upper portion of said gate-cut structure.
3. The method of claim 1, wherein removing said upper portion of
said gate-cut structure and an underlying portion of said gate
insulation layer comprises: performing a first etching process to
remove a portion of said gate insulation layer positioned on said
upper surface of said upper portion of said gate-cate structure;
performing a second etching process to remove said upper portion of
said gate-cut structure and thereby expose portions of said gate
insulation layer; and performing a third etching process to remove
said portions of said gate insulation layer exposed by said removal
of said upper portion of said gate-cut structure.
4. The method of claim 1, wherein said sacrificial gate structure
comprises one of amorphous silicon, polysilicon, or titanium oxide,
said lower portion of said gate-cut structure comprises one of
silicon germanium, germanium or titanium oxide and said upper
portion of said gate-cut structure comprises one of silicon carbon
or SiOC.
5. The method of claim 1, wherein said final gate structure
comprises a high-k (k value of 10 or greater) gate insulation layer
and a gate electrode that comprises at least one metal-containing
layer of material, said gate separation structure comprises at
least one of silicon nitride, silicon dioxide, or a low-k
insulating material (k value of 3.3. or less) and said first and
second transistor devices are FinFET devices.
6. The method of claim 1, wherein forming said sacrificial gate
structure and said gate-cut structure within said sacrificial gate
structure comprises: forming spaced-apart first portions of said
sacrificial gate structure; forming a first material for said lower
portion of said gate-cut structure in spaces between said
spaced-apart first portions of said sacrificial gate structure;
recessing said first material to form cavities above said recessed
first material between said spaced-apart first portions of said
sacrificial gate structure; forming a second material for said
upper portion of said gate-cut structure in said cavities, wherein
said second material is different from said first material; and
forming second portions of said sacrificial gate structure above
said second material.
7. The method of claim 1, wherein forming said sacrificial gate
structure and said gate-cut structure within said sacrificial gate
structure comprises: forming spaced-apart first portions of said
sacrificial gate structure; forming a first material for said lower
portion of said gate-cut structure in spaces between said
spaced-apart first portions of said sacrificial gate structure,
said first material having an upper surface that is substantially
planar with an upper surface of said spaced-apart first portions of
said sacrificial gate structure; forming a second material for said
upper portion of said gate-cut structure on said upper surface of
said first material, wherein said second material is different from
said first material; and forming second portions of said
sacrificial gate structure above said second material.
8. A method of cutting a final gate structure into first and second
final gate structures for first and second transistor devices
laterally separated by isolation material, comprising: forming a
sacrificial gate structure and a gate-cut structure within said
sacrificial gate structure at a position located above said
isolation material, said gate-cut structure comprising an upper
portion and a lower portion by: forming spaced-apart first portions
of said sacrificial gate structure; forming a first material for
said lower portion of said gate-cut structure in spaces between
said spaced-apart first portions of said sacrificial gate
structure; recessing said first material to form cavities above
said recessed first material between said spaced-apart first
portions of said sacrificial gate structure; forming a second
material for said upper portion of said gate-cut structure in said
cavities, wherein said second material is different from said first
material; and forming second portions of said sacrificial gate
structure above said second material; forming a replacement gate
cavity by removing said sacrificial gate structure and said lower
portion of said gate-cut structure, said replacement gate cavity
comprising a space vertically below said upper portion of said
gate-cut structure; forming a final gate structure in said
replacement gate cavity and in said space under said upper portion
of said gate-cut structure, wherein forming said final gate
structure comprises forming a gate insulation layer comprised of a
high-k material on all exposed surfaces of said upper portion of
said gate-cut structure; performing a first etching process to
remove a portion of said gate insulation layer positioned on an
upper surface of said upper portion of said gate-cate structure;
performing a second etching process to remove said upper portion of
said gate-cut structure and thereby expose portions of said gate
insulation layer; and performing a third etching process to remove
said portions of said gate insulation layer exposed by said removal
of said upper portion of said gate-cut structure to define an
opening that exposes a portion of said final gate structure;
removing said exposed portion of said final gate structure to
define a gate-cut opening that separates said final gate structure
into said first and second final gate structures; and forming a
gate separation structure in said gate-cut opening, said gate
separation structure comprising an insulating material.
9. The method of claim 8, wherein said sacrificial gate structure
comprises one of amorphous silicon, polysilicon, or titanium oxide,
said lower portion of said gate-cut structure comprises one of
silicon germanium, germanium or titanium oxide and said upper
portion of said gate-cut structure comprises one of silicon carbon
or SiOC.
10. The method of claim 8, wherein said final gate structure
comprises a gate electrode that comprises at least one
metal-containing layer of material, said gate separation structure
comprises at least one of silicon nitride, silicon dioxide, or a
low-k insulating material (k value of 3.3. or less) and said first
and second transistor devices are FinFET devices.
11. A method of cutting a final gate structure into first and
second final gate structures for first and second transistor
devices laterally separated by isolation material, comprising:
forming a sacrificial gate structure and a gate-cut structure
within said sacrificial gate structure at a position located above
said isolation material, said gate-cut structure comprising an
upper portion and a lower portion by: forming spaced-apart first
portions of said sacrificial gate structure; forming a first
material for said lower portion of said gate-cut structure in
spaces between said spaced-apart first portions of said sacrificial
gate structure, said first material having an upper surface that is
substantially planar with an upper surface of said spaced-apart
first portions of said sacrificial gate structure; forming a second
material for said upper portion of said gate-cut structure on said
upper surface of said first material, wherein said second material
is different from said first material; and forming second portions
of said sacrificial gate structure above said second material;
forming a replacement gate cavity by removing said sacrificial gate
structure and said lower portion of said gate-cut structure, said
replacement gate cavity comprising a space vertically below said
upper portion of said gate-cut structure; forming a final gate
structure in said replacement gate cavity and in said space under
said upper portion of said gate-cut structure, wherein forming said
final gate structure comprises forming a gate insulation layer
comprised of a high-k material on all exposed surfaces of said
upper portion of said gate-cut structure; performing a first
etching process to remove a portion of said gate insulation layer
positioned on an upper surface of said upper portion of said
gate-cut structure; performing a second etching process to remove
said upper portion of said gate-cut structure and thereby expose
portions of said gate insulation layer; performing a third etching
process to remove said portions of said gate insulation layer
exposed by said removal of said upper portion of said gate-cut
structure to define an opening that exposes a portion of said final
gate structure; removing said exposed portion of said final gate
structure to define a gate-cut opening that separates said final
gate structure into said first and second final gate structures;
and forming a gate separation structure in said gate-cut opening,
said gate separation structure comprising an insulating
material.
12. The method of claim 11, wherein said sacrificial gate structure
comprises one of amorphous silicon, polysilicon, or titanium oxide,
said lower portion of said gate-cut structure comprises one of
silicon germanium, germanium or titanium oxide and said upper
portion of said gate-cut structure comprises one of silicon carbon
or SiOC.
13. The method of claim 11, wherein said final gate structure
comprises a gate electrode that comprises at least one
metal-containing layer of material, said gate separation structure
comprises at least one of silicon nitride, silicon dioxide, or a
low-k insulating material (k value of 3.3. or less) and said first
and second transistor devices are FinFET devices.
Description
BACKGROUND
1. Field of the Disclosure
[0001] The present disclosure generally relates to the fabrication
of integrated circuits, and, more particularly, to various methods
of cutting gate structures in a self-aligned manner and to various
embodiments of a multilayer gate-cut pillar structure.
2. Description of the Related Art
[0002] In modern integrated circuits, such as microprocessors,
storage devices and the like, a very large number of circuit
elements, especially transistors, are provided on a restricted chip
area. Field Effect Transistors ("FETs") come in a variety of shapes
and forms, e.g., planar transistors, FinFET transistors, vertical
transistors, nanowire devices, etc.
[0003] In advanced integrated circuit (IC) products, the gate
structures for the transistor devices are typically manufactured
using well-known replacement gate (or "gate-last") manufacturing
techniques. In general, the replacement gate manufacturing
technique involves the formation of a sacrificial (or "dummy") gate
structure comprised of a sacrificial gate insulation layer (e.g.,
silicon dioxide) and a layer of a sacrificial gate electrode
material (e.g., polysilicon or amorphous silicon). The sacrificial
gate structures are initially formed as continuous line-type
structures that extend across the entire substrate, including
across both active regions and isolation regions located between
active regions.
[0004] The long continuous line-type sacrificial gate structures
are formed by depositing the materials for the sacrificial gate
structures across the entire substrate, forming a patterned gate
etch mask above the deposited sacrificial gate materials and
performing one or more etching processes through the patterned gate
etch mask to remove the exposed portions of the sacrificial gate
materials. At that point, a spacer structure will be formed
adjacent the long continuous line-type sacrificial gate structures.
Various process operations are performed with the sacrificial gate
structure in position, e.g., source/drain implantation processes,
the formation of epi semiconductor material in the source/drain
regions of the transistor devices, etc.
[0005] At some point after other processing has occurred, e.g.,
after formation of epi material in the source/drain regions of the
devices, a patterned etch mask--a "gate-cut" mask--is formed above
the product. The gate cut mask includes openings at locations where
it is desired to remove or "cut" portions of the long continuous
line-type sacrificial gate structures so as to form or define
individual portions or segments of the original long continuous
line-type sacrificial gate structures. One or more etching
processes are performed to remove exposed portions of the gate cap
and the sacrificial gate structure and thereby form a gate cut
opening between the now-separate individual portions or segments of
the original long continuous line-type sacrificial gate structures.
An insulating material will be formed in the gate cut opening.
Eventually, these individual portions or segments of the original
long continuous line-type sacrificial gate structures will be
removed and replaced with final replacement gate structures.
[0006] As device dimensions continue to decrease and as packing
densities of transistor devices on a substrate continue to
increase, various problems have arisen as it relates to performing
the gate-cut process operation involved when using traditional
replacement gate manufacturing techniques. For example, as device
scaling continues, the critical dimension (CD) of the gate cut
opening (in the gate width direction of the transistors) continues
to shrink. Additionally, due to the closer spacing between adjacent
transistor devices, it is very important that the gate cut opening
be located as precisely as possible in the exact middle of the
space between adjacent transistor devices. Any offset in the
placement of the gate cut opening and/or forming the gate cut
opening with a larger than desired CD can be problematic as it
relates to the formation of additional materials and structures on
the IC product as manufacturing operations proceed. Such problems
may make the formation of quality replacement gate structures more
difficult and may result in decreased device performance or
complete device failure.
[0007] The present disclosure is directed to various methods of
cutting gate structures in a self-aligned manner and to various
embodiments of a multilayer gate-cut pillar structure and
integrated circuit products that incorporate such structures that
may solve or at least reduce one or more of the problems described
above.
SUMMARY
[0008] The following presents a simplified summary of the disclosed
embodiment in order to provide a basic understanding of some
aspects of the subject matter disclosed herein. This summary is not
an exhaustive overview of all of the subject matter disclosed
herein. It is not intended to identify key or critical elements of
the subject matter disclosed herein or to delineate the scope of
any claims directed to any of the subject matter disclosed herein.
Its sole purpose is to present some concepts in a simplified form
as a prelude to the more detailed description that is discussed
later in the application.
[0009] Generally, the present disclosure is directed to various
methods of cutting gate structures in a self-aligned manner and to
various embodiments of a multilayer gate-cut pillar structure and
integrated circuit products that incorporate such structures. One
illustrative method disclosed herein includes forming a sacrificial
gate structure and a gate-cut structure within the sacrificial gate
structure at a location positioned above an isolation material, the
gate-cut structure having an upper portion and a lower portion, and
forming a replacement gate cavity by removing the sacrificial gate
structure and the lower portion of the gate-cut structure, the
replacement gate cavity having a space vertically below the upper
portion of the gate-cut structure. In this example, the method
further includes forming a final gate structure in the replacement
gate cavity and in the space under the upper portion of the
gate-cut structure, wherein forming the final gate structure
includes forming a gate insulation layer of the final gate
structure on all exposed surfaces of the upper portion of the
gate-cut structure, removing the upper portion of the gate-cut
structure and an underlying portion of the gate insulation layer to
define an opening that exposes a portion of the final gate
structure, removing the exposed portion of the final gate structure
to define a gate-cut opening that separates the final gate
structure into first and second final gate structures, and forming
a gate separation structure in the gate-cut opening, the gate
separation structure comprising an insulating material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The disclosure may be understood by reference to the
following description taken in conjunction with the accompanying
drawings, in which like reference numerals identify like elements,
and in which:
[0011] FIGS. 1-66 depict one illustrative method of cutting gate
structures in a self-aligned manner, various embodiments of a
multilayer gate-cut pillar structure and various novel integrated
circuit (IC) product structures; and
[0012] FIGS. 67-98 depict yet another illustrative method of
cutting gate structures in a self-aligned manner, various
embodiments of a multilayer gate-cut pillar structure and various
novel integrated circuit (IC) product structures.
[0013] While the subject matter disclosed herein is susceptible to
various modifications and alternative forms, specific embodiments
thereof have been shown by way of example in the drawings and are
herein described in detail. It should be understood, however, that
the description herein of specific and illustrative embodiments is
not intended to limit the invention to the particular forms
disclosed, but on the contrary, the intention is to cover all
modifications, equivalents, and alternatives falling within the
spirit and scope of the invention as defined by the appended
claims.
DETAILED DESCRIPTION
[0014] Various illustrative embodiments of the invention are
described below. In the interest of clarity, not all features of an
actual implementation are described in this specification. It will
of course be appreciated that in the development of any such actual
embodiment, numerous implementation-specific decisions must be made
to achieve the developers' specific goals, such as compliance with
system-related and business-related constraints, which will vary
from one implementation to another. Moreover, it will be
appreciated that such a development effort might be complex and
time-consuming, but would nevertheless be a routine undertaking for
those of ordinary skill in the art having the benefit of this
disclosure.
[0015] The present subject matter will now be described with
reference to the attached figures. Various structures, systems and
devices are schematically depicted in the drawings for purposes of
explanation only and so as to not obscure the present disclosure
with details that are well known to those skilled in the art.
Nevertheless, the attached drawings are included to describe and
explain illustrative examples of the present disclosure. The words
and phrases used herein should be understood and interpreted to
have a meaning consistent with the understanding of those words and
phrases by those skilled in the relevant art. No special definition
of a term or phrase, i.e., a definition that is different from the
ordinary and customary meaning as understood by those skilled in
the art, is intended to be implied by consistent usage of the term
or phrase herein. To the extent that a term or phrase is intended
to have a special meaning, i.e., a meaning other than that
understood by skilled artisans, such a special definition will be
expressly set forth in the specification in a definitional manner
that directly and unequivocally provides the special definition for
the term or phrase.
[0016] The present disclosure is directed to various methods of
cutting gate structures in a self-aligned manner and to various
embodiments of a multilayer gate-cut pillar structure and
integrated circuit products that incorporate such structures. The
methods and devices disclosed herein may be employed in
manufacturing products using a variety of technologies, e.g., NMOS,
PMOS, CMOS, etc., and they may be employed in manufacturing a
variety of different devices, e.g., memory products, logic
products, ASICs, etc. As will be appreciated by those skilled in
the art after a complete reading of the present application, the
inventions disclosed herein may be employed in forming integrated
circuit products using transistor devices in a variety of different
configurations, e.g., planar devices, FinFET devices, etc. In the
illustrative examples depicted herein, the transistor devices will
be FinFET devices. Thus, the presently claimed inventions should
not be considered to be limited to any particular form of
transistors. Of course, the claimed inventions should not be
considered to be limited to the illustrative examples depicted and
described herein. With reference to the attached figures, various
illustrative embodiments of the methods and devices disclosed
herein will now be described in more detail. The various layers of
material described below may be formed by performing any of a
variety of different known techniques, e.g., a chemical vapor
deposition (CVD) process, an atomic layer deposition (ALD) process,
a thermal growth process, spin-coating techniques, etc. Moreover,
as used herein and in the attached claims, the word "adjacent" is
to be given a broad interpretation and should be interpreted to
cover situations where one feature actually contacts another
feature or is in close proximity to that other feature.
[0017] FIGS. 1-98 depict various illustrative methods of cutting
gate structures in a self-aligned manner, various embodiments of a
multilayer gate-cut pillar structure and various novel integrated
circuit (IC) product 100 structures. FIG. 1 is a simplistic plan
view of one illustrative embodiment of an IC product 100 that may
be formed using the methods described herein. FIG. 1 depicts a
plurality of fins 103A-C (collectively referenced using the numeral
103) as well as a plurality a plurality of gates 106 (numbered 1-2
for ease of reference) that will eventually be formed on the IC
product for various transistor devices. Each of the gates 106
comprise a final gate structure 108 (depicted in dashed lines).
Various cross-sectional views of the product 100 (views "A-A",
"X-X", "Y-Y and "Z-Z") depicted in the attached drawings are taken
where indicated in FIG. 1. The cross-sectional views Y-Y and Z-Z
are through the axial length of the gates 106 in the gate width
(GW) direction of the transistor devices. The cross-sectional views
A-A and X-X are taken in the gate length (GL--current transport)
direction of the transistor devices. The view X-X is a
cross-sectional view taken through the long axis of the fin 103B.
Additionally, the area 105 in FIG. 1 depicts the location at which
a portion of the axial length of the final gate structure 108 of
gate 2 will be cut using the methods and devices disclosed herein.
In the illustrative example depicted herein, the transistor devices
are FinFET devices. The cross-sectional view A-A in the drawings is
taken through gate number 2 in the gate length (GL) direction of
the transistor devices at the location 105 where the gate structure
108 of gate 2 will be cut.
[0018] The substrate 102 (see FIG. 2) may have a variety of
configurations, such as the depicted bulk silicon configuration.
The substrate 102 may also have a semiconductor-on-insulator (SOI)
configuration that includes a bulk semiconductor layer, a buried
insulation layer and an active semiconductor layer positioned on
the buried insulation layer, wherein semiconductor devices are
formed in and above the active layer. The substrate 102 may be made
of silicon or it may be made of materials other than silicon. Thus,
the terms "substrate" or "semiconductor substrate" should be
understood to cover all semiconducting materials and all forms of
such materials. Additionally, various doped regions, e.g., halo
implant regions, well regions and the like, are not depicted in the
attached drawings.
[0019] FIGS. 2-4 depict the product 100 after several process
operations were performed. More specifically, the fins 103 were
formed in the substrate 102 using traditional manufacturing
techniques. For example, a patterned fin-formation etch mask 104
(comprised of, for example, a layer of silicon dioxide 104A and a
layer of silicon nitride 104B) was formed above the substrate 102.
Thereafter, one or more etching processes, e.g., anisotropic
etching processes, were performed through the patterned
fin-formation etch mask 104 to form a plurality of fin-formation
trenches 102X in the substrate 102 and thereby define the plurality
of fins 103. The width and height of the fins 103 may vary
depending upon the particular application. Additionally, the
overall size, shape and configuration of the fin-formation trenches
102X and fins 103 may vary depending on the particular application.
Next, a recessed layer of insulating material 107 (e.g., silicon
dioxide) with a recessed upper surface 107R was formed between the
fins 103 by performing traditional manufacturing techniques.
[0020] FIGS. 5-7 depict the product 100 after several process
operations were performed. First, a conformal deposition process
was performed to form a relatively thin layer of insulating
material 109, e.g., silicon dioxide, on the product 100.
Thereafter, sacrificial material 110 was blanket-deposited on the
product and an anisotropic etching process was performed to form a
plurality of spacers 110S. The spacers 110S extend axially along
the sides of the fins 103 in the gate length direction of the
devices. Note that the space between fins 103A-103B is
substantially filled with a block 110X of the material 110 as the
fin pitch between the fins 103A-B may effectively not allow for
formation of individual sacrificial spacers 110S in the space
between the fins 103A-B. The spacers 110S may be of any desired
thickness (as measured at their base). The sacrificial material 110
may be any material, e.g., amorphous silicon, polysilicon, titanium
oxide, etc. In one illustrative process flow disclosed herein, the
final gate structures 108 may be manufactured using replacement
gate manufacturing techniques. In such a situation, the material
selected for the sacrificial material 110 may be the same as the
material selected for the sacrificial gate structures formed in
replacement gate manufacturing processes.
[0021] FIGS. 8-10 depict the product 100 after several process
operations were performed. First, a second sacrificial material 112
was formed across the product 100 in the spaces between the
sacrificial spacers 110S. Thereafter, a CMP and/or etch-back
process was performed on the sacrificial material 112 such that the
upper surface of the sacrificial material 112 is substantially
planar with the upper surface of the insulating material 109 as
well as the uppers surface of the block 110X of the sacrificial
material 110. As will be described more fully below, in one
illustrative process flow, the sacrificial material 112 will become
a part of a novel multilayer gate-cut structure 118. The
sacrificial material 112 may be comprised of any material that may
be selectively etched relative to the material of the sacrificial
material 110. For example, the sacrificial material 112 may be
comprised of silicon-germanium, germanium, titanium oxide, etc. The
sacrificial material 112 may be formed by performing a traditional
CVD deposition process so as to overfill the spaces between the
sacrificial spacers 110S.
[0022] FIGS. 11-13 depict the product 100 after a recess etching
process was performed on the sacrificial material 112 such that it
has a recessed upper surface 112R. The amount of recessing of the
sacrificial material 112 may vary depending upon the particular
application. In one illustrative embodiment, based upon current-day
technology, the sacrificial material 112 may be recessed about
10-30 nm.
[0023] FIGS. 14-16 depict the product 100 after several process
operations were performed. First, a layer of material 114 was
formed across the product 100 above the recessed layer of
sacrificial material 112 in the spaces between the sacrificial
spacers 110S. Thereafter, a CMP and/or etch-back process was
performed on the layer of material 114 such that the upper surface
of the layer of material 114 is substantially planar with the upper
surface of the insulating material 109 as well as the upper surface
of the block 110X of the sacrificial material 110. As will be
described more fully below, in one illustrative process flow, the
layer of material 114 will become a part of a novel multilayer
gate-cut structure 118. The layer of material 114 may be comprised
of any material that may be selectively etched relative to the
material of the sacrificial material 110 and the layer of
sacrificial material layer 112. For example, the layer of material
114 may be comprised of silicon-carbon, SiOC, etc. The layer of
material 114 may be formed by performing a traditional CVD
deposition process so as to overfill the spaces between the
sacrificial spacers 110S above the recessed layer of sacrificial
material 112.
[0024] FIGS. 17-19 depict the product 100 after several process
operations were performed. First, one or more etching process were
performed to remove the exposed portions of the layer of insulating
material 109 so as to expose the portion 104B of the patterned etch
mask 104. Thereafter, the portions 104B of the patterned etch mask
104 was removed. As part of these process operations, portions of
the layer of insulating material 109 positioned above the portion
104A of the patterned etch mask 104 may also be removed selectively
relative to surrounding materials. If desired, a brief etching
process may be performed to insure that the desired portions of the
layer of insulating material 109 are removed. At the conclusion of
these process operations, the layer 104A of the patterned etch mask
104 may still cover the upper surface of the fins 103. These
process operations result in the formation of recesses or cavities
113 above the fins 103.
[0025] FIGS. 20-22 depict the product 100 after several process
operations were performed. First, additional sacrificial material
110 (designated 110A) was deposited across the product 100 so as to
overfill the cavities 113 above the fins 103. Thereafter, a CMP
and/or etch-back process was performed to planarize the upper
surface of the additional sacrificial material 110A. At that point,
a layer of sacrificial gate cap material 116 was blanket-deposited
across the product and above the additional sacrificial material
110A. The layer of sacrificial gate cap material 116 may be
comprised of any of a variety of different materials, e.g., silicon
nitride, and it may be formed to any desired thickness. If desired,
a CMP and/or etch-back process may be performed on the upper
surface of the layer of sacrificial gate cap material 116 to
planarize its upper surface.
[0026] FIGS. 24-26A/B depict the product 100 after several process
operations were performed. First, a patterned masking layer (not
shown, e.g., a patterned layer of photoresist or OPL) was formed
above the sacrificial gate cap material 116 using traditional
manufacturing operations. Thereafter, one or more etching processes
were performed though the patterned etch mask to remove exposed
portions of the sacrificial gate cap material 116, the materials
110 and the portion 104A of the patterned etch mask 104. These
process operations result in the formation of sacrificial gate
structures 117A, 117B for gates 1 and 2, respectively, with
sacrificial gate caps 116 positioned thereabove across the fins
103. Note that these process operations also remove the portions of
the material 114 and the material 112 in the areas between the
sacrificial gate structure 117A-B (see FIG. 23) and the formation
of a plurality of multilayer gate-cut pillar structures 118
(included within the dashed-line region 120). In this embodiment,
at this point in the process flow, the multilayer gate-cut pillar
structure 118 comprises a lower section comprised of the material
112 and an upper portion comprised of the material 114. FIGS. 26A-B
are cross-sectional views of the multilayer gate-cut pillar
structure 118 in the gate width (GW) and the gate-length (GL)
direction of the devices. With reference to FIG. 26A, the
dimensions of the multilayer gate-cut pillar structure 118 at the
bottom (118X) and at the top (118Y) in the gate width (GW)
direction of the devices may vary depending upon the particular
application. The upper dimension 118Y will typically be wider than
the bottom 118X due to the self-aligned manner in which the
multilayer gate-cut pillar structure 118 is formed between the
spacers 110S. With reference to FIG. 26B, the dimensions of the
multilayer gate-cut pillar structure 118 at the bottom (118S) and
at the top (118T) in the gate length (GL) direction of the devices
will typically be approximately the same and typically correspond
to the critical dimension of the final gate structures 108 for the
transistor devices.
[0027] FIGS. 27-30 depict the product 100 after several process
operations were performed. First, sidewall spacers 122, e.g.,
silicon nitride, were formed adjacent the sacrificial gate
structures 117A-B by performing a conformal deposition process and
thereafter performing an anisotropic etching process. Then, epi
semiconductor material 124 was formed in the source/drain regions
of the devices. Next, a conformal contact etch stop layer (not
shown) was formed on the spacers 122 and the epi material 124.
Then, a layer of insulating material 126, e.g., silicon dioxide,
was blanket-deposited across the product so as to overfill the
spaces between the spacers 122 and above the contact etch stop
layer and the epi material 124. Thereafter, a CMP and/or etch-back
process was performed to planarize the upper surface of the layer
of insulating material 126 with the sacrificial gate caps 116.
[0028] FIGS. 31-34 depict the product 100 after a CMP process was
performed to remove the sacrificial gate caps 116 and thereby
expose the sacrificial gate structures 117A-B for removal.
[0029] In one illustrative process flow, FIGS. 35-38 depict the
product 100 after an etching process was performed to selectively
remove the sacrificial materials 110 relative to the surrounding
materials including the multilayer gate-cut pillar structures 118.
This process operation removes the sacrificial materials 110A of
the sacrificial gate structures 117A-B, the sacrificial spacers
110S and the blocks 110X of sacrificial material 110 and results in
the formation of a plurality of replacement gate cavities 119.
[0030] In one illustrative process flow, FIGS. 39-42 depict the
product 100 after an etching process was performed to selectively
remove the lower sacrificial material portion 112 of the multilayer
gate-cut pillar structures 118 relative to the surrounding
materials including the upper portion (material 114) of the
multilayer gate-cut pillar structures 118. This results in the
formation of spaces 121 vertically below the remaining upper
portion (material 114) of the multilayer gate-cut pillar structures
118. The spaces 121 effectively become part of the replacement gate
cavities 119. Thereafter, another etching process was performed to
selectively remove the exposed portions of the insulating layers
104A and 109 so as to thereby expose the upper surfaces 103S and
sidewalls 103R of the fins 103. Of course, as will be appreciated
by those skilled in the art, in other process flows, depending upon
the materials selected for the materials 110 and 112, the materials
110 and 112 may be removed by performing a single etching
process.
[0031] FIGS. 43-46 depict the product 100 after several process
operations were performed to form final replacement gate structures
108 in the gate cavities 119 and to form a final gate cap layer 138
above the final gate structure 108. Note that the materials for the
final gate structure 108 are also formed in the spaces 121 (see,
e.g., FIG. 41) under the remaining upper portions (material 114) of
the multilayer gate-cut pillar structures 118. In the illustrative
example depicted herein, the final gate structures 108 are
manufactured using known replacement gate manufacturing techniques.
Using that manufacturing technique, the materials for the final
gate structures 108 are sequentially formed in the gate cavities
119 between the spacers 122 and in the spaces 121. The final gate
structures 108 are typically comprised of a high-k gate insulation
layer 108A, such as hafnium oxide, a material having a dielectric
constant greater than 10, etc., and one or more conductive material
layers that function as the conductive gate electrode 108B of the
gate structure 108. For example, one or more work-function
adjusting metal layers (not separately shown), e.g., titanium,
tantalum, titanium nitride, tantalum nitride, titanium carbide,
etc., and a bulk conductive material (not separately shown), such
as tungsten, may be deposited to form the conductive gate electrode
108B. Note that the high-k gate insulation layer 108A is formed on
all exposed surfaces of the remaining upper portions (material 114)
of the multilayer gate-cut pillar structures 118, i.e., on the
surfaces of the upper portion (material 114) that are not in
contact with the sidewall spacers 122 (see FIGS. 43 and 46). After
the conductive materials of the gate electrode 108B are deposited,
a recess etching process may be performed on the conductive
materials such that the gate electrode 108B has a recessed upper
surface 108R that is positioned at a level that is below the level
of the upper surface 114S of the remaining upper portion 114 of the
initial multilayer gate-cut pillar structures 118 (see FIG. 44).
The amount of recessing of the conductive gate materials may vary
depending upon the particular application, e.g., 15-60 nm. Note
that the high-k gate insulation layer 108A remains in position
around the remaining upper portion 114 of the initial multilayer
gate-cut pillar structures 118 at this point in the process flow.
Thereafter, in this particular embodiment, the final gate caps 138
were formed on the product 100 above the recessed gate materials
and within the gate cavities 119 by depositing gate cap material
above the recessed gate materials and performing a CMP process
operation to planarize the upper surface of the final gate caps 138
with the upper surface of the layer of insulating material 126.
[0032] FIGS. 47-50 depict the product 100 after a patterned etch
mask 140, e.g., a patterned layer of photoresist or OPL, with an
opening 140A formed therein, was formed above the product 100. The
patterned etch mask 140 is typically referred to as a "gate-cut"
mask, as the opening 140A is positioned at the approximate location
105 (see FIG. 1) where it is desired to cut or remove a portion of
the axial length of the final gate structure 108 for gate 2. In
practice, there will be thousands of the openings 140A formed in
the gate-cut mask 140. As will be appreciated by those skilled in
the art after a complete reading of the present application, using
the methods disclosed herein, due to the presence of one of the
remaining upper portions (material 114) of the multilayer gate-cut
pillar structures 118, the physical size and placement (overlay) of
the opening 140A relative to the desired location of the cut 105 of
the gate structure 108 is somewhat relaxed as compared to prior art
process flows. For example, using the methods disclosed herein, the
critical dimension of the opening 140A (in the gate width
direction) may be somewhat larger than the final desired critical
dimension of the actual gate cut opening in the gate structure 108,
and precise overlay of the opening 140A at the desired location of
the ultimate gate cut may not be required.
[0033] FIGS. 51-54 depict the product 100 after several process
operations were performed. First, a timed, anisotropic etching
process was performed on the final gate cap 138 so as to remove
portions of the gate cap 138 under the opening 140A and above the
remaining upper portion 114 of the initial multilayer gate-cut
pillar structures 118. With reference to FIG. 53, note that, in
this example, the critical dimension of the opening 140A (in the
gate width direction of the devices) is greater than the critical
dimension of the remaining upper portion 114 of the initial
multilayer gate-cut pillar structures 118 in the same gate width
direction. This initial etching process stops on the high-k gate
insulation layer 108A positioned on the upper surface 114S.
Thereafter, another etching process was performed to remove the
exposed portions of the high-k insulating material 108A so as to
expose the upper surface 114S of the remaining upper portion 114 of
the initial multilayer gate-cut pillar structure 118. Note that, in
the example depicted in the drawings, at the conclusion of these
etching processes, the entire upper surface 114S of the remaining
upper portion 114 of the initial multilayer gate-cut pillar
structure 118 is exposed due to the larger size opening 140A and
the depicted precise overlay of the opening 140A with respect to
the remaining upper portion 114 of the initial multilayer gate-cut
pillar structure 118. However, as will be appreciated by those
skilled in the art after a complete reading of the present
application, using the methods disclosed herein, such precision in
overlay of the opening 140A with respect to the upper portion 114
(as depicted in the drawing) is not required. For example, if the
opening 140A was laterally offset to the left in FIG. 53 (as
indicated by dashed line 140X) from the idealized position shown in
the drawings such that the opening 140A was only positioned
vertically above less than an entirety of the upper surface 114S,
the methods disclosed may still be used to perform the desired gate
cutting activities.
[0034] FIGS. 55-58 depict the product 100 after several process
operations were performed. First, an etching process was performed
to remove the remaining upper portion 114 of the initial multilayer
gate-cut pillar structures 118. Thereafter, another etching process
was performed to remove the portions of the high-k gate insulation
layer 108A exposed by the removal of the remaining upper portion
114 of the initial multilayer gate-cut pillar structure 118. These
process operations result in the exposure of a portion 144 of the
final gate structure 108 of gate 2 at the location 105 wherein it
is desired to cut the gate 108. Note that this is a self-aligned
process in that the portion 144 of the final gate structure 108
that is removed is the result of the removal of materials and is
not the result of directly etching the gate structure 108 through a
patterned etch mask having an opening in the patterned mask layer
that corresponds to the final desired size of the gate cut
opening.
[0035] FIGS. 59-62 depict the product 100 after one or more etching
processes were performed to remove at least the conductive gate
electrode 108B portion of the exposed portions of the gate
structure 108 of gate 2 selectively relative to the surrounding
materials. This process operation results in the formation of a
gate-cut opening 150 in the gate structure 108 of gate 2 that
effectively cuts the gate structure 108 of gate 2 into separate
first 151 and second 153 gate structures (see FIG. 61). In the
depicted example, both the conductive gate electrode 108B and the
high-k insulating layer 108A are removed selectively relative to
the surrounding materials.
[0036] FIGS. 63-66 depict the product 100 after several process
operations were performed. First, the patterned etch mask 140 was
removed. Next, a deposition process was performed so as to overfill
the gate cut opening 150 with an insulating material, e.g., silicon
nitride, silicon dioxide, a mixture of two or more materials of
silicon oxide, silicon nitride and silicon carbide, a low-k
insulating material (k value of 3.3. or less). Thereafter, one or
more CMP process operations and/or etch-back process operations
were performed that stop on the upper surface of the gate caps 138.
This process operation removes excess amounts of the insulating
material outside of the gate-cut opening 150. As a result, the
remaining insulating material in the gate-cut opening 150
constitutes an insulating gate separation structure 152 with an
upper surface that is substantially planar with the upper surface
of the gate caps 138. At the point of processing depicted in FIGS.
63-66, the fabrication of the product 100 may be completed by
performing traditional manufacturing techniques to form various
standard features on the IC product 100. For example, one or more
layers of insulating material (not shown) may be formed on the
product 100. At that point, traditional manufacturing operations
may be performed to form various contact structures that
conductively contact various components of the transistor devices,
e.g., source/drain regions, the gate structures, etc.
[0037] FIGS. 67-98 depict yet other illustrative methods of cutting
gate structures in a self-aligned manner, various embodiments of a
multilayer gate-cut pillar structure and various novel integrated
circuit (IC) product structures. Relative to the previous process
flow, in this process flow, the sacrificial material layer 112 will
be recessed at a later point in the process flow.
[0038] FIGS. 67-69 depict the product 100 at a point in the process
flow that corresponds to that depicted in FIGS. 8-10 above, i.e.,
after the formation of the layer of sacrificial material 112 and
the planarization of its upper surface.
[0039] FIGS. 70-72 depict the product after the activities
described above with reference to FIGS. 17-19 were performed to
remove the exposed portions of the layer of insulating material 109
and, thereafter, the portions 104B of the patterned etch mask
104.
[0040] FIGS. 73-75 depict the product 100 after the activities
described above with reference to FIGS. 20-22 were performed to
deposit and planarize additional sacrificial material 110
(designated 110A) across the product 100 so as to overfill the
cavities 113 above the fins 103 and thereafter to deposit a layer
of sacrificial gate cap material 116 across the product and above
the additional sacrificial material 110 (designated 110A).
[0041] FIGS. 76-78A/B depict the product 100 after the activities
described above with reference to FIGS. 23-26A/B were performed to
form the above-described sacrificial gate structures 117A, 117B for
gates 1 and 2, respectively, with sacrificial gate caps 116
positioned thereabove, across the fins 103. With reference to FIG.
78A, the dimensions of the material 112 portion of the multilayer
gate-cut pillar structure 118 at the bottom (118X) and at the top
(118Y) in the gate width (GW) direction of the devices may vary
depending upon the particular application. As before, the upper
dimension 118Y will typically be wider than the bottom 118X due to
the self-aligned manner in which the multilayer gate-cut pillar
structure 118 is formed between the spacers 110S. With reference to
FIG. 78B, the dimensions of the material 112 portion of the
multilayer gate-cut pillar structure 118 at the bottom (118S) and
at the top (118T) in the gate length (GL) direction of the devices
will typically be approximately the same and typically correspond
to the critical dimension of the final gate structures 108 for the
transistor devices.
[0042] FIGS. 79-82 depict the product 100 after the activities
described above with reference to FIGS. 27-30 were performed to
form the sidewall spacers 122 and the layer of insulating material
126 across the product so as to overfill the spaces between the
spacers 122. FIGS. 79-82 also depict the process operations
performed to remove the sacrificial gate caps 116 and thereby
expose the sacrificial gate structures 117A-B for removal, as
described above in connection with FIGS. 31-34.
[0043] FIGS. 83-86 depict the product 100 after a recess etching
process was performed on the sacrificial materials 110 relative to
the surrounding materials so as to expose the upper surface of the
sacrificial material 112 (see FIG. 86) positioned above the
isolation material 107. The material 110A now has a recessed upper
surface 110R. The amount of recessing of the conductive gate
materials may vary depending upon the particular application.
[0044] FIGS. 87-90 depict the product after the activities
described above with reference to FIGS. 11-13 were performed to
recess the sacrificial material 112 such that it has a recessed
upper surface 112R.
[0045] FIGS. 91-94 depict the product 100 after several process
operations were performed. First, the above-described layer of
material 114 was formed across the product 100 above the recessed
layer of sacrificial material 112 and in the spaces between the
sacrificial spacers 110S. As initially deposited, the layer of
material has an as-deposited upper surface that is positioned above
the upper surface of the layer of insulating material 126, i.e.,
the layer of material over-fills all of the underlying openings and
spaces on the product 100. Thereafter, a CMP process was performed
on the layer of material 114 such that the upper surface of the
layer of material 114 was substantially planar with the upper
surface of the insulating material 126. At that point, a recess
etching process was performed on the layer of material 114 such
that it has a recessed upper surface 114R that is substantially
planar with the upper surfaces 110R of the block 110X of the
sacrificial material 110. As best seen in FIG. 91, these process
operations clear the layer of material 114 from above the upper
surface of the sacrificial gate structures 117A-B. With reference
to FIGS. 92 and 93, these process operations result in the
formation of a plurality of the above-described multilayer gate-cut
pillar structures 118 (included within the dashed-line region
120).
[0046] FIGS. 95-98 depict the product after the activities
described above with reference to FIGS. 35-42 were performed to (1)
remove the sacrificial materials 110 relative to the surrounding
materials including the multilayer gate-cut pillar structures 118
and thereby form the above-described replacement gate cavities 119,
(2) selectively remove the lower sacrificial material portion 112
of the multilayer gate-cut pillar structures 118 relative to the
surrounding materials including the upper portion (material 114) of
the multilayer gate-cut pillar structures 118 so as to form the
above-described spaces 121 vertically below the remaining upper
portion (material 114) of the multilayer gate-cut pillar structures
118; and (3) selectively remove the exposed portions of the
insulating layers 104A and 109 so as to thereby expose the upper
surfaces 103S and sidewalls 103R of the fins 103. At the point of
processing depicted in FIGS. 94-98, the product may be completed by
performing the processing steps described in FIGS. 43-66 above.
[0047] The particular embodiments disclosed above are illustrative
only, as the invention may be modified and practiced in different
but equivalent manners apparent to those skilled in the art having
the benefit of the teachings herein. For example, the process steps
set forth above may be performed in a different order. Furthermore,
no limitations are intended to the details of construction or
design herein shown, other than as described in the claims below.
It is therefore evident that the particular embodiments disclosed
above may be altered or modified and all such variations are
considered within the scope and spirit of the invention. Note that
the use of terms, such as "first," "second," "third" or "fourth" to
describe various processes or structures in this specification and
in the attached claims is only used as a shorthand reference to
such steps/structures and does not necessarily imply that such
steps/structures are performed/formed in that ordered sequence. Of
course, depending upon the exact claim language, an ordered
sequence of such processes may or may not be required. Accordingly,
the protection sought herein is as set forth in the claims
below.
* * * * *