U.S. patent application number 13/552992 was filed with the patent office on 2014-01-23 for image transfer process employing a hard mask layer.
This patent application is currently assigned to INTERNATIONAL BUSINESS MACHINES CORPORATION. The applicant listed for this patent is Ryan O. Jung, Sivananda K. Kanakasabapathy, Yunpeng Yin. Invention is credited to Ryan O. Jung, Sivananda K. Kanakasabapathy, Yunpeng Yin.
Application Number | 20140024219 13/552992 |
Document ID | / |
Family ID | 49946773 |
Filed Date | 2014-01-23 |
United States Patent
Application |
20140024219 |
Kind Code |
A1 |
Jung; Ryan O. ; et
al. |
January 23, 2014 |
IMAGE TRANSFER PROCESS EMPLOYING A HARD MASK LAYER
Abstract
At least one mask layer formed over a substrate includes at
least one of a dielectric material and a metallic material. By
forming a first pattern in one of the at least one mask layer, a
patterned mask layer including said first pattern is formed. An
overlying structure including a second pattern that includes at
least one blocking area is formed over said patterned mask layer.
Portions of said patterned mask layer that do not underlie said
blocking area are removed. The remaining portions of the patterned
mask layer include a composite pattern that is an intersection of
the first pattern and the second pattern. The patterned mask layer
includes a dielectric material or a metallic material, and thus,
enables high fidelity pattern transfer into an underlying material
layer.
Inventors: |
Jung; Ryan O.; (Rensselaer,
NY) ; Kanakasabapathy; Sivananda K.; (Niskayuna,
NY) ; Yin; Yunpeng; (Niskayuna, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Jung; Ryan O.
Kanakasabapathy; Sivananda K.
Yin; Yunpeng |
Rensselaer
Niskayuna
Niskayuna |
NY
NY
NY |
US
US
US |
|
|
Assignee: |
INTERNATIONAL BUSINESS MACHINES
CORPORATION
Armonk
NY
|
Family ID: |
49946773 |
Appl. No.: |
13/552992 |
Filed: |
July 19, 2012 |
Current U.S.
Class: |
438/703 ;
257/E21.215 |
Current CPC
Class: |
H01L 21/31144 20130101;
Y10T 428/24802 20150115; H01L 21/0337 20130101; H01L 21/32139
20130101; H01L 21/0338 20130101 |
Class at
Publication: |
438/703 ;
257/E21.215 |
International
Class: |
H01L 21/306 20060101
H01L021/306 |
Claims
1. A method of patterning a structure comprising: forming an
underlying material layer on a substrate; forming a stack of two
mask layers comprising a dielectric material and a metallic
material, respectively, over said underlying material layer;
forming a first pattern in one of said two mask layers, wherein a
patterned mask layer including said first pattern is formed by
remaining portions of said one of said two mask layers, while
another of said two mask layers remains unpatterned; forming an
overlying structure including a second pattern over said patterned
mask layer, wherein said second pattern includes at least one
blocking area; removing portions of said patterned mask layer that
do not underlie said blocking area, wherein remaining portions of
said patterned mask layer include a composite pattern that is an
intersection of said first pattern and said second pattern;
applying a photoresist material directly on surfaces of said
patterned mask layer and on surfaces of said another of said two
mask layers that remains unpatterned; patterning said photoresist
material to form at least one photoresist block portion having an
additional pattern directly on a topmost surface of said another of
said two mask layers; transferring a derived pattern including said
composite pattern and a pattern of said at least one photoresist
block portion as component patterns into said another of said two
mask layers; and transferring said derived pattern into said
underlying material layer employing remaining portions of said
another of said two mask layers as an etch mask.
2. The method of claim 1, further comprising: forming a stack of a
first organic planarizing layer (OPL) and a first antireflective
coating (ARC) layer on said at least one mask layer; and forming a
patterned structure including said first pattern over said first
ARC layer, wherein said forming of said first pattern in said one
of said at least one mask layer comprises transferring said first
pattern into said one of said at least one mask layer.
3. The method of claim 2, further comprising etching said first ARC
layer and said first OPL employing said patterned structure as an
etch mask, wherein a patterned first ARC layer and a patterned
first OPL are formed.
4. The method of claim 3, wherein said transferring of said first
pattern into said one of said at least one mask layer comprises
etching said one of said at least one mask layer employing said
patterned first ARC layer as an etch mask.
5. The method of claim 4, further comprising removing said
patterned first OPL selective to said patterned mask layer prior to
forming said overlying structure.
6. The method of claim 2, wherein said forming of said patterned
structure comprises forming a set of spacer structures.
7. The method of claim 6, wherein said set of spacer structures is
formed by: forming mandrel structures over said first ARC layer;
depositing a conformal material layer over said mandrel structures;
and anisotropically etching said conformal material layer, wherein
remaining disjoined portions of said conformal material layer are
said set of spacer structures.
8. The method of claim 7, further comprising removing said mandrel
structures selective to said set of spacer structures and said
first ARC layer.
9. The method of claim 7, wherein said forming of said mandrel
structures comprise: depositing a mandrel material layer over said
first ARC layer; and patterning said mandrel material layer to form
said mandrel structures.
10. The method of claim 2, wherein said patterned structure
comprises a set of first photoresist material portions comprising a
first photoresist material and a set of second photoresist material
portions comprising a second photoresist material that is different
from said first photoresist material.
11. The method of claim 2, wherein said forming of said overlying
structure comprises forming a stack of a second OPL, a second ARC
layer, and a photoresist layer over said patterned mask layer.
12. The method of claim 11, further comprising lithographically
patterning said photoresist layer with said second pattern, wherein
said second pattern includes at least one opening that is a
complement of said at least one blocking area.
13. The method of claim 12, further comprising etching said second
ARC layer and an upper portion of said second OPL employing said
photoresist layer as an etch mask.
14. The method of claim 13, wherein said removing of said portions
of said patterned mask layer that do not underlie said blocking
area comprises etching said portions of said patterned mask layer
from within an area of said at least one opening after said etching
of said upper portion of said second OPL.
15. The method of claim 14, further comprising removing remaining
portions of said second OPL selective to said remaining portions of
said patterned mask layer.
16.-17. (canceled)
18. The method of claim 1, wherein said transferring of said
derived pattern into said underlying material layer comprises
etching said underlying material layer employing a combination of
said remaining portions of said patterned mask layer and said at
least one photoresist block portion as an etch mask.
19. The method of claim 1, wherein said derived pattern is a union
of said composite pattern and said additional pattern.
20. The method of claim 1, wherein said underlying material layer
comprises a gate conductor layer.
21. The method of claim 1, further comprising removing said
remaining portions of said patterned mask layer selective to said
underlying material layer after said transferring of said derived
pattern.
22. The method of claim 1, wherein said at lest one mask layer
comprises a stack, from bottom to top, of a dielectric mask layer
and a metallic mask layer.
23. The method of claim 1, wherein said at least one mask layer
comprises a stack, from bottom to top, of a metallic mask layer and
a dielectric material layer.
24. The method of claim 1, wherein said at least one mask layer
consists of a dielectric mask layer.
25. The method of claim 1, wherein said at least one mask layer
consists of a metallic mask layer.
26. The method of claim 1, further comprising removing said
remaining portions of said patterned mask layer selective to
remaining portions of said another of said two mask layers after
said transferring of said derived pattern.
Description
BACKGROUND
[0001] The present disclosure generally relates to a process for
manufacturing semiconductor structures, and particularly to an
image transfer process employing a hard mask layer to memorize a
composite pattern, and structures for effecting the same.
[0002] A trilayer lithography process as known in the art employs
an organic material layer such as an amorphous carbon layer in
order to transfer a composite image of two independent images. The
sidewalls of the organic material layer are formed with a
significant level of line edge roughness and line width roughness
during a pattern transfer etch that forms a pattern in the organic
material layer employing an overlying layer as a patterned mask
because the organic material layer is prone to lateral etching. The
line edge roughness and the line width roughness of the organic
material layer are further increased during a subsequent pattern
transfer etch that transfers the pattern in the organic material
layer into an underlying layer employing the organic material layer
as an etch mask. The increased line edge roughness and line width
roughness in the organic material layer is at least partly
transferred into the underlying layer. Thus, the fidelity of
pattern transfer is degraded due to the lateral etching of the
organic material layer in the material stack employed for the
trilayer lithography process.
BRIEF SUMMARY
[0003] At least one mask layer formed over a substrate includes at
least one of a dielectric material and a metallic material. By
forming a first pattern in one of the at least one mask layer, a
patterned mask layer including said first pattern is formed. An
overlying structure including a second pattern that includes at
least one blocking area is formed over said patterned mask layer.
Portions of said patterned mask layer that do not underlie said
blocking area are removed. The remaining portions of the patterned
mask layer include a composite pattern that is an intersection of
the first pattern and the second pattern. The patterned mask layer
includes a dielectric material or a metallic material, and thus,
enables high fidelity pattern transfer into an underlying material
layer.
[0004] According to an aspect of the present disclosure, a method
of patterning a structure is provided. At least one mask layer
including at least one of a dielectric material and a metallic
material is formed over a substrate. A first pattern is formed in
one of the at least one mask layer. A patterned mask layer
including the first pattern is thus formed. An overlying structure
including a second pattern over the patterned mask layer is
subsequently formed. The second pattern includes at least one
blocking area. Portions of the patterned mask layer that do not
underlie the blocking area are removed. Remaining portions of the
patterned mask layer include a composite pattern that is an
intersection of the first pattern and the second pattern.
[0005] According to another aspect of the present disclosure, a
lithographic structure is provided, which includes an underlying
material layer located on a substrate, at least one mask layer
including at least one of a dielectric material and a metallic
material and located over the underlying material layer, an organic
planarizing layer (OPL) located over the at least one mask layer,
an antireflective coating (ARC) layer located on the OPL, and a
patterned structure located over the ARC layer.
[0006] According to yet another aspect of the present disclosure,
another lithographic structure is provided, which includes an
underlying material layer located on a substrate, a patterned mask
layer including at least one of a dielectric material and a
metallic material and located over the underlying material layer,
an organic planarizing layer (OPL) located over the patterned mask
layer, an antireflective coating (ARC) layer located on the OPL,
and a photoresist layer located over the ARC layer and including at
least one opening therein.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0007] FIG. 1 is a vertical cross-sectional view of a first
exemplary structure after deposition of an underlying material
layer, and optional dielectric material layer, a dielectric mask
layer, a metallic mask layer, a first organic planarizing layer
(OPL), a first antireflective coating (ARC) layer, and mandrel
structures according to a first embodiment of the present
disclosure.
[0008] FIG. 2 is a vertical cross-sectional view of the first
exemplary structure after deposition of a conformal material layer
according to the first embodiment of the present disclosure.
[0009] FIG. 3 is a vertical cross-sectional view of the first
exemplary structure after formation of a set of spacer structures
according to the first embodiment of the present disclosure.
[0010] FIG. 4 is a vertical cross-sectional view of the first
exemplary structure after removal of the mandrel structures
according to the first embodiment of the present disclosure.
[0011] FIG. 5 is a vertical cross-sectional view of the first
exemplary structure after transfer of a first pattern in the set of
spacer structures into the first ARC layer according to the first
embodiment of the present disclosure.
[0012] FIG. 6 is a vertical cross-sectional view of the first
exemplary structure after transfer of the first pattern into the
first OPL according to the first embodiment of the present
disclosure.
[0013] FIG. 7 is a vertical cross-sectional view of the first
exemplary structure after transfer of the first pattern into the
metallic mask layer according to the first embodiment of the
present disclosure.
[0014] FIG. 8 is a vertical cross-sectional view of the first
exemplary structure after removal of the first OPL according to the
first embodiment of the present disclosure.
[0015] FIG. 9 is a vertical cross-sectional view of the first
exemplary structure after application of a second OPL, a second ARC
layer, and a first photoresist layer, and lithographic patterning
of the first photoresist layer with a second pattern according to
the first embodiment of the present disclosure.
[0016] FIG. 10 is a vertical cross-sectional view of the first
exemplary structure after transferring the second pattern down to
an upper portion of the second OPL according to the first
embodiment of the present disclosure.
[0017] FIG. 11 is a vertical cross-sectional view of the first
exemplary structure after removal of the second ARC layer according
to the first embodiment of the present disclosure.
[0018] FIG. 12 is a vertical cross-sectional view of the first
exemplary structure after removal of physically exposed portions of
the metallic mask layer according to the first embodiment of the
present disclosure.
[0019] FIG. 13 is a vertical cross-sectional view of the first
exemplary structure after removal of the second OPL according to
the first embodiment of the present disclosure.
[0020] FIG. 14 is a vertical cross-sectional view of the first
exemplary structure application of a second photoresist layer and
lithographic patterning of the second photoresist layer with a
third pattern according to the first embodiment of the present
disclosure.
[0021] FIG. 15 is a vertical cross-sectional view of the first
exemplary structure after transfer of a derived pattern which is a
union of the third pattern and a composite pattern that is an
intersection of the first pattern and the second pattern into the
dielectric mask layer and the optional dielectric material layer
according to the first embodiment of the present disclosure.
[0022] FIG. 16 is a vertical cross-sectional view of the first
exemplary structure after transfer of the derived pattern into an
upper portion of the underlying material layer and removal of the
metallic mask layer according to the first embodiment of the
present disclosure.
[0023] FIG. 17 is a vertical cross-sectional view of the first
exemplary structure after transfer of the derived pattern to the
bottom of the underlying material layer and removal of the
dielectric mask layer according to the first embodiment of the
present disclosure.
[0024] FIG. 18 is a vertical cross-sectional view of a second
exemplary structure after deposition of an underlying material
layer, and optional dielectric material layer, a metallic mask
layer, a dielectric mask layer, a first organic planarizing layer
(OPL), a first antireflective coating (ARC) layer, and mandrel
structures according to a second embodiment of the present
disclosure.
[0025] FIG. 19 is a vertical cross-sectional view of the second
exemplary structure after transfer of the first pattern into the
dielectric mask layer according to the second embodiment of the
present disclosure.
[0026] FIG. 20 is a vertical cross-sectional view of the second
exemplary structure after transfer of the second pattern into the
dielectric mask layer and removal of the second OPL according to
the second embodiment of the present disclosure.
[0027] FIG. 21 is a vertical cross-sectional view of the second
exemplary structure after transfer of the derived pattern into an
upper portion of the underlying material layer and removal of the
dielectric mask layer according to the second embodiment of the
present disclosure.
[0028] FIG. 22 is a vertical cross-sectional view of a third
exemplary structure after deposition of an underlying material
layer, and optional dielectric material layer, a mask layer, a
first organic planarizing layer (OPL), a first antireflective
coating (ARC) layer, and mandrel structures according to a third
embodiment of the present disclosure
[0029] FIG. 23 is a vertical cross-sectional view of the third
exemplary structure after transfer of the first pattern into the
mask layer according to the third embodiment of the present
disclosure.
[0030] FIG. 24 is a vertical cross-sectional view of the third
exemplary structure after transfer of the second pattern into the
mask layer and removal of the second OPL according to the third
embodiment of the present disclosure.
[0031] FIG. 25 is a vertical cross-sectional view of the third
exemplary structure after transfer of the derived pattern into an
upper portion of the underlying material according to the third
embodiment of the present disclosure.
[0032] FIG. 26 is a vertical cross-sectional view of a fourth
exemplary structure after deposition of an underlying material
layer, and optional dielectric material layer, a dielectric mask
layer, a metallic mask layer, a first organic planarizing layer
(OPL), a first antireflective coating (ARC) layer, and a
photoresist layer and lithographic patterning of the photoresist
layer according to a fourth embodiment of the present
disclosure.
[0033] FIG. 27 is a vertical cross-sectional view of a fifth
exemplary structure after deposition of an underlying material
layer, and optional dielectric material layer, a metallic mask
layer, a dielectric mask layer, a first organic planarizing layer
(OPL), a first antireflective coating (ARC) layer, and a
photoresist layer and lithographic patterning of the photoresist
layer according to a fifth embodiment of the present
disclosure.
[0034] FIG. 28 is a vertical cross-sectional view of a sixth
exemplary structure after deposition of an underlying material
layer, and optional dielectric material layer, a mask layer, a
first organic planarizing layer (OPL), a first antireflective
coating (ARC) layer, and a photoresist layer and lithographic
patterning of the photoresist layer according to a sixth embodiment
of the present disclosure.
[0035] FIG. 29 is a vertical cross-sectional view of a seventh
exemplary structure after deposition of an underlying material
layer, and optional dielectric material layer, at least one mask
layer, a first organic planarizing layer (OPL), a first
antireflective coating (ARC) layer, and application and patterning
of a primary photoresist layer, and application and patterning of a
secondary photoresist layer according to a seventh embodiment of
the present disclosure.
DETAILED DESCRIPTION
[0036] As stated above, the present disclosure relates to an image
transfer process employing a hard mask layer to memorize a
composite pattern and structures for effecting the same, which are
now described in detail with accompanying figures. It is noted that
like reference numerals refer to like elements across different
embodiments. The drawings are not necessarily drawn to scale.
[0037] FIG. 1 is a vertical cross-sectional view of a first
exemplary structure after deposition of an underlying material
layer, and optional dielectric material layer, a dielectric mask
layer, a metallic mask layer, a first organic planarizing layer
(OPL), a first antireflective coating (ARC) layer, and mandrel
structures according to a first embodiment of the present
disclosure.
[0038] Referring to FIG. 1, a first exemplary structure according
to a first embodiment of the present disclosure includes a
substrate 10 and a material stack formed thereupon. The substrate
10 can include a semiconductor substrate having semiconductor
devices (not shown) therein. The semiconductor devices can include,
for example, field effect transistors, junction transistors,
diodes, resistors, capacitors, inductors, or any other
semiconductor device known in the art. The substrate 10 may, or may
not, include contact-level dielectric material layers (not shown)
and/or interconnect level dielectric material layers (not shown) as
well as embedded contact via structures (not shown) and/or embedded
wiring level metal interconnect structures. Alternately, the
topmost portion of the substrate 10 can include a semiconductor
material such as single crystalline silicon.
[0039] An underlying material layer 20L can be formed on the
substrate 10. The underlying material layer 20L can be a conductive
material layer, a plurality of conductive material layers, a single
dielectric material layer, a plurality of dielectric material
layers, or a stack of at least one dielectric material layer and a
conductive material layer. For example, the underlying material
layer 20L can be a stack of gate level layers, a wiring-level
dielectric material layer, a contact-level dielectric material
layer, a conductive material layer such as a metal layer or a doped
semiconductor layer. Exemplary materials that can be included in
the underlying material layer include, but are not limited to, gate
dielectric materials known in the art, gate conductor materials
known in the art, doped semiconductor materials, and conductive
metallic materials, silicon oxide, silicon nitride, silicon
oxynitride, organosilicate glass, and stacks thereof. The
underlying material layer 20L can be deposited, for example, by
chemical vapor deposition (CVD), spin coating, or by any other
deposition method known in the art. The thickness of the underlying
material layer 20L can be from 10 nm to 2,000 nm, although lesser
and greater thicknesses can also be employed. In one embodiment,
the underlying material layer 20L can be a stack of a gate
dielectric layer and a gate conductor layer.
[0040] An optional dielectric material layer 30L can be optionally
deposited on the top surface of the underlying material layer 20L.
The optional dielectric material layer 30L can be, for example, a
silicon nitride layer or a silicon oxide layer. If the optional
dielectric material layer 30L includes silicon nitride or silicon
oxide, the optional dielectric material layer 30L can be deposited
by a chemical vapor deposition (CVD). The thickness of the optional
dielectric material layer 30L can be from 30 nm to 300 nm, although
lesser and greater thicknesses can also be employed. In one
embodiment, the underlying material layer 20L can be a stack of
gate dielectric layer and a gate conductor layer, and the optional
dielectric material layer 30L can be a gate cap dielectric layer
including silicon nitride or silicon oxide.
[0041] At least one mask layer 45L is subsequently deposited on the
optional dielectric material layer 30L or the underlying material
layer 20L (if an optional dielectric material layer is not
present). The at least one mask layer 45L can include at least one
of a dielectric material and a metallic material. The at least one
mask layer 45L can be a stack, from bottom to top, of a dielectric
mask layer 40L and a metallic mask layer 50L. Alternately, the at
least one mask layer 45L can be a stack, from bottom to top, of a
metallic mask layer 50L and a dielectric mask layer 40L. Yet
alternately, the at least one mask layer 45L can be a single layer
of a dielectric mask layer 40L. Still alternately, the at least one
mask layer 45L can be a single layer of a metallic mask layer
50L.
[0042] The dielectric mask layer 40L includes a dielectric
material, which can be silicon oxide, silicon nitride, silicon
oxynitride, a dielectric metal oxide such as HfO.sub.2, LaO.sub.2,
or TiO.sub.2, or a combination thereof. The dielectric mask layer
40L can be deposited, for example, by chemical vapor deposition
(CVD), physical vapor deposition (PVD), or a combination thereof.
The thickness of the dielectric mask layer 40L can be from 10 nm to
100 nm, although lesser and greater thicknesses can also be
employed.
[0043] If the dielectric mask layer 40L includes silicon oxide, the
dielectric mask layer 40L can be deposited by a chemical vapor
deposition (CVD) using tetraethylorthosilicate (TEOS) as a
precursor material. Silicon oxide derived from TEOS, commonly
referred to as TEOS oxide, can be deposited by low pressure
chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor
deposition (PECVD).
[0044] A metallic mask layer 50L is deposited on the dielectric
mask layer 40L. The metallic mask layer 50L includes a conductive
material. Exemplary conductive materials that can be employed for
the metallic mask layer 50L include, but are not limited to, TiN,
TaN, WN, TiC, TaC, WC, Ti, Ta, W, and combinations thereof. For
example, the metallic mask layer 50L can be a TiN layer. The
metallic mask layer 50L can be deposited, for example, by physical
vapor deposition (PVD), chemical vapor deposition (CVD), or a
combination thereof. The thickness of the metallic mask layer 50L
can be from 10 nm to 100 nm, although lesser and greater
thicknesses can also be employed.
[0045] A first organic planarizing layer (OPL) 60L is deposited on
the top surface of the at least one mask layer 45L, which can be
the top surface of the metallic mask layer 50L. The first OPL 60L
includes a non-photosensitive organic polymer including carbon,
hydrogen, oxygen, and optionally fluorine. For example, the first
OPL 60L can include hydrocarbons and/or hydrofluorocarbons. The
first OPL 60L can be formed, for example, by spin coating. The
thickness of the first OPL 60L can be from 30 nm to 300 nm,
although lesser and greater thicknesses can also be employed.
[0046] A first antireflective coating (ARC) layer 62L is deposited
on the first OPL 60L. The antireflective coating (ARC) layer is
herein referred to as the first antireflective coating (ARC) layer
62L. The first ARC layer 62L can include a hydrocarbon based
material having a different material composition than the first OPL
60L. In one embodiment, the first ARC layer 62L comprises silicon
at an atomic concentration from 1% to 50%. In another embodiment,
the first ARC layer 62L comprises a refractory metal at an atomic
concentration from 1% to 50%. The first ARC layer 62L controls
reflectivity of the surface (i.e., the surface of the metallic mask
layer 50L) over which the first OPL 60L is patterned by reducing
standing waves and optical notching. The thickness of the first ARC
layer 62L may be from 10 nm to 150 nm, and typically from 20 nm to
80 nm, although lesser and greater thicknesses are explicitly
contemplated herein. The first ARC layer 62L can be applied, for
example, by spin coating.
[0047] A mandrel material layer (not shown) is deposited on the
first ARC layer 62L. The mandrel material layer can include a
photoresist, an amorphous carbon layer, or a material that can be
removed selective to the material of a conformal material layer to
be subsequently deposited. The mandrel material layer is deposited
as a blanket layer (unpatterned layer), for example, by chemical
vapor deposition (CVD) or spin coating. The thickness of the
mandrel material layer can be from 30 nm to 300 nm, although lesser
and greater thicknesses can also be employed.
[0048] In one embodiment, the mandrel material layer is a
photoresist layer that can be directly patterned by lithographic
exposure and development. The mandrel material layer is patterned
by lithographic means, i.e., exposure and development, to form
mandrel structures 70. The lithographic pattern may be a pattern of
a periodic array, or may be an irregular pattern. In one
embodiment, the lithographic pattern is a pattern of a regular
periodic array. The lithographic pattern may contain an array of
lines and spaces, or may contain a pattern of via holes in a matrix
of the mandrel material layer, or may contain a pattern of isolated
structures separated from one another by a contiguous cavity that
laterally surrounds each isolated structure, i.e., each mandrel
structure 70. Each of the mandrel structures 70 may be separated
from one another as in the case of a lithographic pattern
containing an array of lines and spaces, or may be adjoined among
one another as in the case of a lithographic pattern containing an
array of via holes.
[0049] In case the pattern in the mandrel structures 70 comprises a
periodic one dimensional array, the pitch of the pattern in the
mandrel structures 70 is a lithographic dimension, which is herein
referred to as a lithographic pitch p. If the pattern in the
mandrel structures 70 is a pattern of lines and spaces, the
lithographic pitch p is the lateral dimension of a unit pattern
comprising one line and one space. If the pattern in the mandrel
structures 70 is a pattern of via holes in a matrix of a contiguous
mandrel structure 70, the lithographic pitch is the lateral
dimension of a unit pattern comprising at least one via hole. In
addition to having periodicity in one direction at the lithographic
pitch p, the pattern in the mandrel structures 70 may have another
periodicity in another direction. Optionally, overexposure or
underexposure may be employed so that the width of each pattern
between a neighboring pair of the mandrel structures 70 is less
than one half of the lithographic pitch p.
[0050] The lithographic pitch p is a lithographic dimension, i.e.,
a dimension that may be formed by lithographic means. The
lithographic pitch p is the same as, or greater than, the minimum
lithographic pitch that may be obtained by commercially available
lithography tools. For example, if ArF lithography employing 193 nm
wavelength light is used, the lithographic pitch p is the same as,
or greater than 80 nm, which is the lithographic minimum pitch.
[0051] In other embodiments, the mandrel material layer includes
amorphous carbon or other non-photosensitive material. In such
embodiments, a photoresist (not shown) can be applied over the
mandrel material and is lithographically patterned into shapes
including multiple parallel lines. In one embodiment, the multiple
parallel lines can have the same width and the same pitch. The
pitch of the multiple parallel lines is a lithographic pitch, i.e.,
a pitch that can be printed by a single lithographic exposure
employing a commercially available lithography tool and
photoresist. A minimum lithographic pitch is herein referred to as
a critical pitch, and a pitch that is less than the critical pitch
is herein referred to as a sublithographic pitch. The pattern in
the photoresist is transferred into the mandrel material layer to
pattern the mandrel material layer into mandrel structures 70. In
the case amorphous carbon or even amorphous silicon is employed as
the mandrel material, the first OPL layer 60 can be replaced by a
organic layer that has degas temperature higher than the mandrel
deposition temperature. In one embodiment, OPL layer 60 can be
replaced by amorphous carbon material through CVD deposition.
[0052] In one embodiment, the mandrel structures 70 can have
parallel sidewalls. The parallel sidewalls of the mandrel
structures 70 may vertically coincide with parallel sidewalls of
the patterned photoresist, or may be laterally recessed inward (so
that the mandrel structures 70 have lesser widths than the widths
of the patterned photoresist). In one embodiment, the mandrel
structures 70 have a lithographic pitch in one direction, which is
a horizontal direction perpendicular to the parallel sidewalls of
the mandrel structures 70.
[0053] Referring to FIG. 2, a conformal material layer 72L is
deposited on the mandrel structures 70 and the exposed top surface
of the first ARC layer 62L. The conformal material layer 72L is
deposited employing a conformal deposition method such as molecular
layer deposition (MLD), in which multiple reactants are alternately
provided in a process chamber to deposit the conformal material
layer. In MLD, the deposition of the material of the conformal
material layer 72L occurs one molecular layer at a time. The
dielectric material of the conformal material layer 72L can
include, but is not limited to, silicon oxide, silicon nitride, or
a combination thereof. The temperature of the deposition process is
maintained below the decomposition temperature of the material of
the mandrel structures 70.
[0054] In one embodiment, the mandrel structures 70 include a
photoresist, and the conformal material layer includes silicon
dioxide. Silicon oxide can be deposited at room temperature
employing a molecular layer deposition process.
[0055] In another embodiment, the mandrel structures 70 include
amorphous carbon, and the conformal material layer includes silicon
oxide or silicon nitride. Silicon nitride can be deposited at a
temperature about 400.degree. C. employing a molecular layer
deposition process.
[0056] Any other combination of materials for the mandrel
structures 70 and the conformal material layer 72L can be employed
provided that the material of the mandrel structures 70 can
withstand the deposition process for the conformal material layer,
that the conformal material layer 72L can be conformally deposited
on the sidewalls of the mandrel structures 70, and that the
mandrels can be removed selective to the material of the conformal
material layer 72L and the first ARC layer 62L.
[0057] Referring to FIG. 3, an anisotropic etch is performed to
remove horizontal portions of the conformal material layer 72L. The
vertical portions of the conformal material layer 72L that remains
on the vertical sidewalls of the mandrels constitute a set of
spacer structures 72, which include the same dielectric material as
the conformal material layer 72L. Thus, the remaining disjoined
portions of the conformal material layer 72L are the set of spacer
structures 72. In one embodiment, the mandrel structures 70 can be
patterned line structures having parallel vertical sidewalls. Each
spacer structure 72 has a same width, and laterally surrounds and
contacts a mandrel structure 70. Each of said spacer structures 72
can have a same lateral width, which can be the same as the
thickness of the conformal material layer 72 as deposited.
[0058] The pattern in the spacer structures 72 is herein referred
to as a first pattern. The spacer structures 72 collectively
constitute a patterned structure including the first pattern. In
one embodiment, the spacer structures can have a pitch that is one
half of the lithographic pitch p. In this case, the patterned
structure can include spacer structures 72 having a sublithographic
pitch.
[0059] Each of the spacer structures 72 can laterally contact and
laterally surround one of the mandrel structures 70. In one
embodiment, the mandrel structures 70 can include a photoresist
material. In another embodiment, the mandrel structures 70 can
include amorphous carbon.
[0060] Referring to FIG. 4, the mandrel structures 70 are removed
by another etch, which can be an anisotropic etch or an isotropic
etch, that is selective to the materials of the spacer structures
72 and the first ARC layer 62L.
[0061] In one embodiment, the first pattern may include two
patterned line structures within a lithographic pitch p. If the
lithographic pitch is a minimum lithographic pitch that can be
lithographically printed, the width of the spacer structures 72 can
be a sublithographic width, i.e., a width that is less than the
minimum width of a patterned structure that can be formed by single
exposure and development.
[0062] The first exemplary structure illustrated in FIG. 4 is a
lithographic structure, which includes the underlying material
layer 20L located on the substrate 10; at least one mask layer 45L
including at least one of a dielectric material and a metallic
material and located over the underlying material layer 20L; the
first organic planarizing layer (OPL) 60L located over the at least
one mask layer 45L; the first antireflective coating (ARC) layer
62L located on the first OPL 60L; and the patterned structure of
the spacer structures 72 located over the first ARC layer 62L. In
one embodiment, the patterned structure has a pattern of a
plurality of parallel lines, i.e., the first pattern can be a
pattern of a plurality of parallel lines.
[0063] Each of the at least one mask layer 45L can be a blanket
layer having a same thickness throughout, i.e., an unpatterned
material layer. In one embodiment, the at least one mask layer 45L
can be a stack, from bottom to top, of the dielectric mask layer
40L and the metallic mask layer 50L. In another embodiment, the at
least one mask layer 45L can be a stack, from bottom to top, of a
metallic mask layer 50L and a dielectric mask layer 40L. In yet
another embodiment, the at least one mask layer 45L can be a single
layer of a dielectric mask layer 40L. In still another embodiment,
the at least one mask layer 45L can be a single layer of a metallic
mask layer 50L.
[0064] Referring to FIG. 5, the first pattern in the set of spacer
structures 72 is transferred into the first ARC layer 62L by an
anisotropic etch. The set of spacer structures 72 is employed as an
etch mask during the transfer of the first pattern into the first
ARC layer 62L. The first ARC layer 62L becomes a patterned first
ARC layer 62, which includes a plurality of ARC portions that
replicate the first pattern.
[0065] Referring to FIG. 6, the first pattern is transferred into
the first OPL 60L by another anisotropic etch. The anisotropic etch
employs the set of spacer structures 72 and/or the patterned first
ARC layer 62 as the etch mask. For example, the set of spacer
structures 72 can be consumed during an initial portion of the
anisotropic and consumed before the end of the anisotropic etch,
and the patterned first ARC layer 62 can be employed as the etch
mask during a latter portion of the anisotropic etch. Alternately,
the set of spacer structures 72 can be employed as the etch mask
layer throughout the anisotropic etch, and removed selective to the
material of the first OPL 60L after the anisotropic etch. The first
OPL 60L becomes a patterned first OPL 60 by the anisotropic etch,
which includes a plurality of OPL portions. The patterned first OPL
60 includes the first pattern.
[0066] Referring to FIG. 7, the first pattern into at least an
upper portion of the at least one mask layer 45L by an anisotropic
etch. The patterned first ARC layer 62 can be employed as the etch
mask during the anisotropic etch. The first pattern is formed in
one of the at least one mask layer 45L. A patterned mask layer
including the first pattern is thus formed. If the at least one
mask layer 45L includes a stack of multiple mask layers, the
patterned mask layer can be a patterned layer formed from the
topmost layer among the multiple mask layers. If the at least one
mask layer 45L includes a single mask layer, the patterned mask
layer is a patterned layer of the single mask layer. The patterned
first ARC layer 62 can be consumed during the anisotropic etch, or
can be removed after the anisotropic etch. If the patterned first
ARC layer 62 is consumed before the anisotropic etch is completed,
the patterned first OPL 60 can be employed as the etch mask during
the remainder of the anisotropic etch. At least partially patterned
mask layer 45 is thus formed.
[0067] For example, if the at least one mask layer 45L includes a
vertical stack, from bottom to top, of the dielectric mask layer
40L and the metallic mask layer 50L, the first pattern is
transferred into the metallic mask layer 50L. The patterned mask
layer is a patterned metallic mask layer 50 in this case. The at
least partially patterned mask layer 45 includes a stack, from
bottom to top, of the dielectric mask layer 40L and the patterned
metallic mask layer 50.
[0068] If the at least one mask layer 45L includes a vertical
stack, from bottom to top, of a metallic mask layer 50L and a
dielectric mask layer 40L, the first pattern is transferred into
the dielectric mask layer 40L. The patterned mask layer is a
patterned dielectric mask layer (not shown) in this case. The at
least partially patterned mask layer 45 includes a stack, from
bottom to top, of the metallic mask layer 50L and the patterned
dielectric mask layer.
[0069] If the at least one mask layer 45L includes a single
metallic mask layer 50L, the first pattern is transferred into the
metallic mask layer 50L. The patterned mask layer is a patterned
metallic mask layer 50 in this case. The at least partially
patterned mask layer 45 consists of the patterned metallic mask
layer 50.
[0070] If the at least one mask layer 45L includes a single
dielectric mask layer 40L, the first pattern is transferred into
the dielectric mask layer 40L. The patterned mask layer is a
patterned dielectric mask layer in this case. The at least
partially patterned mask layer 45 consists of the patterned
dielectric mask layer.
[0071] The anisotropic etch can be a reactive ion etch employing a
plasma of at least one fluorocarbon gas such as CF.sub.4,
CHF.sub.3, and C.sub.4F.sub.8. Argon or nitrogen can also be added
to the plasma. In general, the chemistry of the anisotropic etch
for etching the metallic mask layer 50L is selected to
simultaneously etch the material of the metallic mask layer 50L and
the patterned first ARC layer 62. Thus, the pattern in the first
OPL 60 is transferred into the metallic mask layer 50L to form a
pattern of trenches therein, and the top surface of the dielectric
mask layer 40L is exposed at the bottom of the trenches.
[0072] Because the at least one mask layer 45L does not include any
organic material and includes only non-organic material(s), line
edge roughness and line width roughness in the transferred first
pattern in the at least partially patterned mask layer 45 is
significantly reduced relative to any process that transfers a
similar pattern into an organic material layer such as an amorphous
carbon layer.
[0073] Referring to FIG. 8, the patterned first OPL 60 is removed
selective to the patterned mask layer, e.g., the patterned metallic
mask layer 50. The patterned first OPL 60 can be removed selective
to the patterned metallic mask layer 50 and the dielectric mask
layer 40L, for example, by ashing.
[0074] Referring to FIG. 9, a second OPL 160L, a second ARC layer
162L, and a first photoresist layer 170 are sequentially applied
over the patterned mask layer, e.g., the patterned metallic mask
layer 50. The first photoresist layer 170 is lithographically
patterned with a second pattern. The second pattern includes at
least one blocking area, which is the area of the remaining
portions of the first photoresist layer 170 after lithographic
exposure and development. At least one opening is formed within the
first photoresist layer. The area of the at least one opening is
the complement of the at least one blocking area.
[0075] The at least one blocking area has lithographic dimensions,
i.e., dimensions that are not less than the minimum lithographic
dimension. In one embodiment, the first photoresist layer 170 can
include a mid-ultraviolet (MUV) photoresist material or a
deep-ultraviolet (DUV) photoresist material.
[0076] The first exemplary structure illustrated in FIG. 9 is a
lithographic structure that includes: the underlying material layer
20L located on the substrate 10; a patterned mask layer including
at least one of a dielectric material and a metallic material and
located over the underlying material layer 20L; the second OPL 160L
located over the patterned mask layer; the second ARC layer 162L
located on the second OPL 160L; and the first photoresist layer 170
located over the second ARC layer 162L and including at least one
opening therein.
[0077] In one embodiment, the patterned mask layer can be the
patterned metallic mask layer 50, and a dielectric mask layer 40L
can be present underneath the patterned metallic mask layer 50. The
dielectric mask layer 40L can be located over the underlying
material layer 20L, and the patterned mask layer includes a
metallic material, and is located on a top surface of the
dielectric mask layer 40L.
[0078] In another embodiment, the patterned mask layer can be a
patterned dielectric mask layer (not shown), and a metallic mask
layer can be present underneath the patterned dielectric mask
layer. The metallic mask layer can be located over the underlying
material layer 20L. The patterned mask layer includes a dielectric
material, and is located on a top surface of the metallic mask
layer.
[0079] In yet another embodiment, the patterned mask layer can be a
patterned metallic mask layer 50 that is in direct contact with the
optional dielectric material layer 30L or the underlying material
layer 20L. In still another embodiment, the patterned mask layer
can be a patterned dielectric mask layer that is in direct contact
with the optional dielectric material layer 30L or the underlying
material layer 20L.
[0080] In one embodiment, the patterned mask layer such as the
patterned metallic mask layer 50 can include a periodic pattern of
a plurality of parallel line structures that are laterally spaced
from one another, i.e., the plurality of portions of the metallic
material that constitute the patterned metallic mask layer 50. In
one embodiment, the periodic pattern can have a lithographic
minimum pitch. In another embodiment, the periodic pattern can have
a sublithographic pitch.
[0081] In one embodiment, the underlying material layer 20L can
include a conductive material layer, and the optional dielectric
material layer 30L can have a different composition than the
patterned mask layer. The conductive material layer can include at
least one of a doped polycrystalline semiconductor material and a
metal layer, and the optional dielectric material layer 30L can
include silicon nitride.
[0082] An overlying structure including the second pattern (e.g.,
the first photoresist layer 170) is present over the patterned mask
layer, e.g., the patterned metallic mask layer 50. The second
pattern includes the at least one blocking area.
[0083] Referring to FIG. 10, the second pattern is transferred down
to an upper portion of the second OPL 160L. The second ARC layer
162L and an upper portion of the second OPL 160L are etched in an
anisotropic etch that employs the first photoresist layer 170 as an
etch mask. The first photoresist layer 170 can be consumed during
the etching of the second OPL 160L.
[0084] An overlying structure including the second pattern (e.g.,
the stack of the upper portion of the second OPL 160L and the
second ARC layer 162L) is present over the patterned mask layer,
e.g., the patterned metallic mask layer 50.
[0085] Referring to FIG. 11, the second ARC layer 162L can be
removed during the etching of the second OPL 160L or in a separate
etch step.
[0086] Referring to FIG. 12, physically exposed portions of the
patterned mask layer, e.g., the patterned metallic mask layer 50,
can be removed selective to the material of the layer contacting
the bottom surface of the patterned mask layer, e.g., the
dielectric mask layer 40L. The portions of the patterned mask layer
that do not underlie the blocking area are removed by etching the
portions of the patterned mask layer from within an area of the at
least one opening, i.e., within the area of the second region R2,
which is the area of the complement of the second pattern. The
remaining portions of the patterned mask layer include a composite
pattern that is an intersection of the first pattern and the second
pattern.
[0087] Referring to FIG. 13, the second OPL 160L can be removed,
for example, by ashing. The remaining portions of the second OPL
160L can be removed selective to the remaining portions of the
patterned mask layer.
[0088] The patterned mask layer can include a plurality of
patterned mask portions that is present over a first region R1 of
the underlying material layer 20L, and the patterned mask layer is
not present over a second region R2 of the underlying material
layer. The plurality of patterned mask portions can be a periodic
array of parallel line structures having a pitch that is not
greater than a minimum lithographic pitch. In one embodiment, the
second region R2 can have a width that is greater than twice the
pitch p (See FIG. 3).
[0089] Because the at least partially patterned mask layer 45 does
not include any organic material and includes only non-organic
material(s), the line edge roughness or line width roughness of the
sidewalls of the at least partially patterned mask layer 45 does
not increase during the removal of the second OPL 160L.
[0090] Referring to FIG. 14, a second photoresist layer can be
optionally applied over the remaining portions of the patterned
mask layer, e.g., the patterned metallic mask layer 50. The second
photoresist layer can be applied, for example, by spin coating. The
second photoresist layer can be lithographically patterned by
lithographic exposure and development to form at least one
photoresist block portion 77 having an additional pattern, which is
herein referred to as a third pattern.
[0091] The third pattern can be any lithographic pattern. The third
pattern is present in the area of the at least one photoresist
block portion 77. In one embodiment, the third pattern can be
present within the area of the second region R2. In one embodiment,
the third pattern can define regions having a lateral dimension
greater than the pitch p (See FIG. 3).
[0092] In one embodiment, a trilayer material stack including an
organic planarizing layer, a silicon-containing anti-reflective
coating (ARC) layer, and a photoresist layer can be employed
instead of the second photoresist layer. The organic planarizing
layer can include the same material as the first OPL 60 or as the
second OPL 160, and can be deposited such that a planar topmost
surface of the organic planarizing layer is formed above the
topmost surfaces of the patterned metallic mask layer 50. The
silicon-containing ARC layer can include any silicon-containing ARC
material known in the art. The photoresist layer can be patterned
with the third pattern. After lithographic exposure and development
of the photoresist layer, physically exposed portions of the
silicon-containing ARC layer can be removed by an etch employing
the remaining portions of the photoresist layer as an etch mask.
Subsequently, physically exposed portions of the organic
planarizing layer are removed by another etch, which can employ
remaining portions of the photoresist layer and/or the
silicon-containing ARC layer as an etch mask. At least one organic
planarizing material portion (and optionally at least one
silicon-containing ARC material portion overlying the at least one
organic planarizing material portion) can be present in the area of
the at least one photoresist block portion 77, and subsequently
serve the function of the at least one photoresist block portion 77
in this embodiment.
[0093] Referring to FIG. 15, a pattern derived from the composite
pattern of the intersection of the first pattern and the second
pattern and from the third pattern is transferred into the rest of
the at least partially patterned mask layer 45 and the optional
dielectric material layer 30L. The derived pattern can be a union
of the third pattern and a composite pattern that is the
intersection of the first pattern and the second pattern. For
example, the derived pattern can be transferred into the dielectric
mask layer 40L and the optional dielectric material layer 30L. The
remaining portions of the dielectric mask layer 40L constitute a
patterned dielectric mask layer 40, and the remaining portions of
the optional dielectric material layer 30L constitute an optional
patterned dielectric material layer.
[0094] Because the at least partially patterned mask layer 45 does
not include any organic material and includes only non-organic
material(s), the line edge roughness or line width roughness of the
sidewalls of the at least partially patterned mask layer 45 does
not increase significantly during the pattern transfer etch that
transfers the derived pattern into the optional dielectric material
layer 30L.
[0095] Referring to FIG. 16, the derived pattern is transferred
into an upper portion of the underlying material layer 20L. The
transfer of the derived pattern into the underlying material layer
20 can be effected by etching the underlying material layer 20L
employing the remaining portions of the patterned mask layer, e.g.,
the patterned metallic material layer 50, and the at least one
photoresist block portion 77 as an etch mask.
[0096] Optionally, the patterned mask layer, e.g., the patterned
metallic mask layer 50, can be removed once the derived pattern is
transferred into any layer between the patterned mask layer and the
underlying material layer 20L. For example, the patterned metallic
mask layer 50 can be removed after the derived pattern is
transferred into the patterned dielectric mask layer 40 and/or the
optional patterned dielectric material layer 30.
[0097] In one embodiment, the patterned mask layer, e.g., the
patterned metallic mask layer 50, can be consumed during the
anisotropic etch that transfers the derived pattern into the
dielectric mask layer 40L, the optional dielectric material layer
30L, and/or the underlying material layer 20L. In another
embodiment, the removal of the patterned mask layer, e.g., the
patterned metallic mask layer 50, can be performed by an etch
process that removes the material of the patterned mask layer
selective to physically exposed material underneath the patterned
mask layer. In one embodiment, the remaining portions of the
patterned mask layer, e.g., the patterned metallic mask layer 50,
can be removed selective to the underlying material layer 20L after
the transfer of the derived pattern. The at least one photoresist
block portion 77 can be consumed during the transfer of the derived
pattern, or alternately, can be removed, for example, by
ashing.
[0098] Referring to FIG. 17, the derived pattern is transferred to
the bottom of the underlying material layer 20L. All materials of
the at least one mask layer 45L are removed. For example, the
patterned dielectric mask layer 40 is removed selective to the
materials of the optional patterned dielectric material layer 30
and the patterned underlying material layer 20.
[0099] Referring to FIG. 18, a second exemplary structure according
to a second embodiment of the present disclosure is derived from
the first exemplary structure of FIG. 1 by altering the at least
one mask layer 45L. Specifically, a vertical stack, from bottom to
top, of the metallic mask layer 50L and the dielectric mask layer
40L is employed for the at least one mask layer 45L. The metallic
mask layer 50L of the second embodiment can have the same
composition and thickness as in the first embodiment, and can be
formed by the same method as in the first embodiment. The
dielectric mask layer 40L of the second embodiment can have the
same composition and thickness as in the first embodiment, and can
be formed by the same method as in the first embodiment.
[0100] Referring to FIG. 19, the processing steps of FIGS. 2-6 can
be performed. Subsequently, the first pattern into at least an
upper portion of the at least one mask layer 45L by an anisotropic
etch. The patterned first ARC layer 62 can be employed as the etch
mask during the anisotropic etch. The first pattern is formed in
one of the at least one mask layer 45L. A patterned mask layer
including the first pattern is thus formed. The patterned first ARC
layer 62 can be consumed during the anisotropic etch, or can be
removed after the anisotropic etch. If the patterned first ARC
layer 62 is consumed before the anisotropic etch is completed, the
patterned first OPL 60 can be employed as the etch mask during the
remainder of the anisotropic etch. At least partially patterned
mask layer 45 is thus formed.
[0101] In this embodiment, the first pattern is transferred into
the dielectric mask layer 40L. The patterned mask layer is a
patterned dielectric mask layer 40. The at least partially
patterned mask layer 45 includes a stack, from bottom to top, of
the metallic mask layer 50L and the patterned dielectric mask layer
45.
[0102] The chemistry of the anisotropic etch for etching the
dielectric mask layer 40L is selected to simultaneously etch the
material of the dielectric mask layer 40L and the patterned first
ARC layer 62. Thus, the pattern in the first OPL 60 is transferred
into the dielectric mask layer 40L to form a pattern of trenches
therein, and the top surface of the metallic mask layer 50L is
exposed at the bottom of the trenches.
[0103] Subsequently, the patterned first OPL 60 is removed
selective to the patterned mask layer, e.g., the patterned
dielectric mask layer 40. The patterned first OPL 60 can be removed
selective to the patterned dielectric mask layer 40 and the
metallic mask layer 50L, for example, by ashing.
[0104] Referring to FIG. 20, processing steps of FIGS. 9-11 are
performed. Subsequently, physically exposed portions of the
patterned mask layer, e.g., the patterned dielectric mask layer 40,
can be removed selective to the material of the layer contacting
the bottom surface of the patterned mask layer, e.g., the metallic
mask layer 50L. The portions of the patterned mask layer that do
not underlie the blocking area are removed by etching the portions
of the patterned mask layer from within an area of the at least one
opening, i.e., within the area of the second region R2, which is
the area of the complement of the second pattern. The remaining
portions of the patterned mask layer include a composite pattern
that is an intersection of the first pattern and the second
pattern.
[0105] The second OPL 160L can then be removed, for example, by
ashing. The remaining portions of the second OPL 160L can be
removed selective to the remaining portions of the patterned mask
layer.
[0106] The patterned mask layer, i.e., the patterned dielectric
mask layer 40, can include a plurality of patterned mask portions
that is present over a first region R1 of the underlying material
layer 20L, and the patterned mask layer is not present over a
second region R2 of the underlying material layer. The plurality of
patterned mask portions can be a periodic array of parallel line
structures having a pitch that is not greater than a minimum
lithographic pitch. In one embodiment, the second region R2 can
have a width that is greater than twice the pitch p (See FIG.
3).
[0107] Referring to FIG. 21, the processing step of FIG. 14 is
performed. Subsequently, a pattern derived from the composite
pattern of the intersection of the first pattern and the second
pattern and from the third pattern is transferred into the rest of
the at least partially patterned mask layer 45 and the optional
dielectric material layer 30L. The derived pattern can be a union
of the third pattern and a composite pattern that is the
intersection of the first pattern and the second pattern. For
example, the derived pattern can be transferred into the metallic
mask layer 50L and the optional dielectric material layer 30L. The
remaining portions of the metallic mask layer 50L constitute a
patterned dielectric mask layer 50, and the remaining portions of
the optional dielectric material layer 30L constitute an optional
patterned dielectric material layer.
[0108] Subsequently, the derived pattern is transferred into an
upper portion of the underlying material layer 20L. The transfer of
the derived pattern into the underlying material layer 20 can be
effected by etching the underlying material layer 20L employing the
remaining portions of the patterned mask layer, e.g., the patterned
dielectric material layer 40, and the at least one photoresist
block portion 77 (See FIG. 15) as an etch mask.
[0109] Optionally, the patterned mask layer, e.g., the patterned
dielectric mask layer 40, can be removed once the derived pattern
is transferred into any layer between the patterned mask layer and
the underlying material layer 20L. For example, the patterned
dielectric mask layer 40 can be removed after the derived pattern
is transferred into the patterned metallic mask layer 50 and/or the
optional patterned dielectric material layer 30.
[0110] In one embodiment, the patterned mask layer, e.g., the
patterned dielectric mask layer 40, can be consumed during the
anisotropic etch that transfers the derived pattern into the
metallic mask layer 50L, the optional dielectric material layer
30L, and/or the underlying material layer 20L. In another
embodiment, the removal of the patterned mask layer, e.g., the
patterned dielectric mask layer 40, can be performed by an etch
process that removes the material of the patterned mask layer
selective to physically exposed material underneath the patterned
mask layer. In one embodiment, the remaining portions of the
patterned mask layer, e.g., the patterned dielectric mask layer 40,
can be removed selective to the underlying material layer 20L after
the transfer of the derived pattern. The at least one photoresist
block portion 77 can be consumed during the transfer of the derived
pattern, or alternately, can be removed, for example, by
ashing.
[0111] The anisotropic etch can be continued to provide the same
structure as the first exemplary structure shown in FIG. 17.
[0112] Referring to FIG. 22, a third exemplary structure according
to a third embodiment of the present disclosure is derived from the
first exemplary structure of FIG. 1 by altering the at least one
mask layer 45L. Specifically, a homogeneous mask layer 145L
including a metallic material or a dielectric material can be
employed for the at least one mask layer 45L. The homogeneous mask
layer 145L can have a same composition throughout. The homogeneous
mask layer 145L can have the same composition as the dielectric
mask layer 40L of the first embodiment, or as the metallic mask
layer 50L of the first embodiment. The thickness of the homogeneous
mask layer 145L can be from 30 nm to 600 nm, although lesser and
greater thicknesses can also be employed. The homogeneous mask
layer 145L can be formed employing methods for forming the
dielectric mask layer 40L or employing methods for forming the
metallic mask layer 50L.
[0113] Referring to FIG. 23, the processing steps of FIGS. 2-6 can
be performed. Subsequently, the first pattern into at least an
upper portion of the homogeneous mask layer 145L by an anisotropic
etch. The patterned first ARC layer 62 can be employed as the etch
mask during the anisotropic etch. The first pattern is formed in
one of the homogeneous mask layer 145L. A patterned mask layer
including the first pattern is thus formed. The patterned first ARC
layer 62 can be consumed during the anisotropic etch, or can be
removed after the anisotropic etch. If the patterned first ARC
layer 62 is consumed before the anisotropic etch is completed, the
patterned first OPL 60 can be employed as the etch mask during the
remainder of the anisotropic etch. A patterned homogeneous mask
layer 145 is thus formed.
[0114] In this embodiment, the first pattern is transferred into
the homogeneous mask layer 145L. The patterned mask layer is a
patterned homogeneous mask layer 145.
[0115] The chemistry of the anisotropic etch for etching the
dielectric mask layer 40L is selected to simultaneously etch the
material of the homogeneous mask layer 145L and the patterned first
ARC layer 62. Thus, the pattern in the first OPL 60 is transferred
into the homogeneous mask layer 145L to form a pattern of trenches
therein, and the top surface of the optional dielectric material
layer 30L is exposed at the bottom of the trenches.
[0116] Subsequently, the patterned first OPL 60 is removed
selective to the patterned mask layer, e.g., the patterned
homogeneous mask layer 145. The patterned first OPL 60 can be
removed selective to the patterned homogeneous mask layer 145 and
the optional dielectric material layer 30L, for example, by
ashing.
[0117] Referring to FIG. 24, processing steps of FIGS. 9-11 are
performed. Subsequently, physically exposed portions of the
patterned mask layer, e.g., the patterned homogeneous mask layer
145, can be removed selective to the material of the layer
contacting the bottom surface of the patterned mask layer, e.g.,
the optional dielectric material layer 30L or the underlying
material layer 20L. The portions of the patterned mask layer that
do not underlie the blocking area are removed by etching the
portions of the patterned mask layer from within an area of the at
least one opening, i.e., within the area of the second region R2,
which is the area of the complement of the second pattern. The
remaining portions of the patterned mask layer include a composite
pattern that is an intersection of the first pattern and the second
pattern.
[0118] The second OPL 160L can then be removed, for example, by
ashing. The remaining portions of the second OPL 160L can be
removed selective to the remaining portions of the patterned mask
layer.
[0119] The patterned mask layer, i.e., the patterned homogeneous
mask layer 145, can include a plurality of patterned mask portions
that is present over a first region R1 of the underlying material
layer 20L, and the patterned mask layer is not present over a
second region R2 of the underlying material layer. The plurality of
patterned mask portions can be a periodic array of parallel line
structures having a pitch that is not greater than a minimum
lithographic pitch. In one embodiment, the second region R2 can
have a width that is greater than twice the pitch p (See FIG.
3).
[0120] Referring to FIG. 25, the processing step of FIG. 14 is
performed. Subsequently, a pattern derived from the composite
pattern of the intersection of the first pattern and the second
pattern and from the third pattern is transferred into the optional
dielectric material layer 30L, if present. The derived pattern can
be a union of the third pattern and a composite pattern that is the
intersection of the first pattern and the second pattern. The
remaining portions of the optional dielectric material layer 30L
constitute an optional patterned dielectric material layer.
[0121] Subsequently, the derived pattern is transferred into an
upper portion of the underlying material layer 20L. The transfer of
the derived pattern into the underlying material layer 20 can be
effected by etching the underlying material layer 20L employing the
remaining portions of the patterned mask layer, e.g., the patterned
homogeneous mask layer 145, and the at least one photoresist block
portion 77 (See FIG. 15) as an etch mask.
[0122] Optionally, the patterned mask layer, e.g., the patterned
homogeneous mask layer 145, can be removed once the derived pattern
is transferred into any layer between the patterned mask layer and
the underlying material layer 20L. For example, the patterned
homogeneous mask layer 145 can be removed after the derived pattern
is transferred into the optional patterned dielectric material
layer 30.
[0123] In one embodiment, the patterned mask layer, e.g., patterned
homogeneous mask layer 145, can be consumed during the anisotropic
etch that transfers the derived pattern into the optional
dielectric material layer 30L and/or the underlying material layer
20L. In another embodiment, the removal of the patterned mask
layer, e.g., the patterned homogeneous mask layer 145, can be
performed by an etch process that removes the material of the
patterned mask layer selective to physically exposed material
underneath the patterned mask layer. In one embodiment, the
remaining portions of the patterned mask layer, e.g., the patterned
homogeneous mask layer 145, can be removed selective to the
underlying material layer 20L after the transfer of the derived
pattern. The at least one photoresist block portion 77 can be
consumed during the transfer of the derived pattern, or
alternately, can be removed, for example, by ashing.
[0124] The anisotropic etch can be continued to provide the same
structure as the first exemplary structure shown in FIG. 17.
[0125] Referring to FIG. 26, a fourth exemplary structure according
to a fourth embodiment of the present disclosure can be derived
from the first exemplary structure of FIG. 1 by not forming the
mandrel structures 70 and by applying and lithographically
patterning a photoresist layer to form a patterned photoresist
layer 80 including a first pattern. The patterned photoresist layer
80 can include a set of photoresist material portions.
[0126] The fourth exemplary structure illustrated in FIG. 26 is a
lithographic structure, which includes the underlying material
layer 20L located on the substrate 10; at least one mask layer 45L
including at least one of a dielectric material and a metallic
material and located over the underlying material layer 20L; the
first organic planarizing layer (OPL) 60L located over the at least
one mask layer 45L; the first antireflective coating (ARC) layer
62L located on the first OPL 60L; and the patterned structure of
the patterned photoresist layer 80 located over the first ARC layer
62L.
[0127] In one embodiment, the patterned structure has a pattern of
a plurality of parallel lines. In one embodiment, the patterned
structure includes a set of photoresist material portions having a
lithographic minimum pitch. The processing step of FIG. 5 can be
subsequently performed employing the patterned photoresist layer 80
as an etch mask. Subsequently, processing steps of FIGS. 6-17 can
be performed.
[0128] Referring to FIG. 27, a fifth exemplary structure according
to a fifth embodiment of the present disclosure can be derived from
the second exemplary structure of FIG. 18 by not forming the
mandrel structures 70 and by applying and lithographically
patterning a photoresist layer to form a patterned photoresist
layer 80 including a first pattern. The patterned photoresist layer
80 can include a set of photoresist material portions.
[0129] In one embodiment, the patterned structure has a pattern of
a plurality of parallel lines. In one embodiment, the patterned
structure includes a set of photoresist material portions having a
lithographic minimum pitch. The processing step of FIG. 5 can be
subsequently performed employing the patterned photoresist layer 80
as an etch mask. Processing steps of the second embodiment can be
subsequently performed.
[0130] Referring to FIG. 28, a sixth exemplary structure according
to a sixth embodiment of the present disclosure can be derived from
the second exemplary structure of FIG. 22 by not forming the
mandrel structures 70 and by applying and lithographically
patterning a photoresist layer to form a patterned photoresist
layer 80 including a first pattern. The patterned photoresist layer
80 can include a set of photoresist material portions.
[0131] In one embodiment, the patterned structure has a pattern of
a plurality of parallel lines. In one embodiment, the patterned
structure includes a set of photoresist material portions having a
lithographic minimum pitch. The processing step of FIG. 5 can be
subsequently performed employing the patterned photoresist layer 80
as an etch mask. Processing steps of the third embodiment can be
subsequently performed.
[0132] Referring to FIG. 29, a seventh exemplary structure a
according to a seventh embodiment of the present disclosure can be
derived from any of the fourth, fifth, and sixth exemplary
structures illustrated in FIGS. 26, 27, and 28 by applying and
patterning multiple photoresist layers instead of employing a
single photoresist layer. For example, a primary photoresist layer
70A can be applied and lithographically patterned, and a secondary
photoresist layer 70B can be subsequently applied and
lithographically patterned.
[0133] The seventh exemplary structure illustrated in FIG. 29 is a
lithographic structure, which includes the underlying material
layer 20L located on the substrate 10; at least one mask layer 45L
including at least one of a dielectric material and a metallic
material and located over the underlying material layer 20L; the
first organic planarizing layer (OPL) 60L located over the at least
one mask layer 45L; the first antireflective coating (ARC) layer
62L located on the first OPL 60L; and the patterned structure of
the spacer structures 72 located over the first ARC layer 62L.
[0134] In one embodiment, the patterned structure has a pattern of
a plurality of parallel lines. In one embodiment, the patterned
structure includes a set of first photoresist material portions
including a first photoresist material (e.g., the primary
photoresist layer 70A) and a set of second photoresist material
portions including a second photoresist material that is different
from the first photoresist material (e.g., the secondary
photoresist layer 70B). The processing step of FIG. 5 can be
subsequently performed employing the patterned photoresist layer 80
as an etch mask. Subsequently, processing steps of FIGS. 6-17 can
be performed.
[0135] The various embodiments of the present disclosure enables
high fidelity transfer of the derived pattern including at least
the composite pattern of the first pattern and the second pattern,
and optionally including an additional pattern (the third pattern).
Due to the absence of any organic material within the at least one
mask layer 45L, the material(s) of the at least one mask layer 45L
is/are not prone to increase in line edge roughness or line width
roughness during the transfer of the first pattern therein, or
during the removal of the patterned first OPL 60, or during the
removal of the second OPL 160L, or during the anisotropic etch that
transfers the derived pattern into the underlying layers.
[0136] While the present disclosure has been particularly shown and
described with respect to preferred embodiments thereof, it will be
understood by those skilled in the art that the foregoing and other
changes in forms and details may be made without departing from the
spirit and scope of the present disclosure. It is therefore
intended that the present disclosure not be limited to the exact
forms and details described and illustrated, but fall within the
scope of the appended claims.
* * * * *