U.S. patent application number 13/600714 was filed with the patent office on 2014-03-06 for methods of forming patterns, and methods of forming integrated circuitry.
This patent application is currently assigned to MICRON TECHNOLOGY, INC.. The applicant listed for this patent is Vishal Sipani. Invention is credited to Vishal Sipani.
Application Number | 20140065823 13/600714 |
Document ID | / |
Family ID | 50032736 |
Filed Date | 2014-03-06 |
United States Patent
Application |
20140065823 |
Kind Code |
A1 |
Sipani; Vishal |
March 6, 2014 |
METHODS OF FORMING PATTERNS, AND METHODS OF FORMING INTEGRATED
CIRCUITRY
Abstract
Some embodiments include methods of forming a pattern. First
lines are formed over a first material, and second lines are formed
over the first lines. The first and second lines form a crosshatch
pattern. The first openings are extended through the first
material. Portions of the first lines that are not covered by the
second lines are removed to pattern the first lines into segments.
The second lines are removed to uncover the segments. Masking
material is formed between the segments. The segments are removed
to form second openings that extend through the masking material to
the first material. The second openings are extended through the
first material. The masking material is removed to leave a
patterned mask comprising the first material having the first and
second openings therein. In some embodiments, spacers may be formed
along the first and second lines to narrow the openings in the
crosshatch pattern.
Inventors: |
Sipani; Vishal; (Boise,
ID) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sipani; Vishal |
Boise |
ID |
US |
|
|
Assignee: |
MICRON TECHNOLOGY, INC.
Boise
ID
|
Family ID: |
50032736 |
Appl. No.: |
13/600714 |
Filed: |
August 31, 2012 |
Current U.S.
Class: |
438/675 ;
257/E21.257; 257/E21.585; 438/703 |
Current CPC
Class: |
H01L 21/0338 20130101;
H01L 21/3088 20130101; H01L 21/76805 20130101; H01L 21/3086
20130101; H01L 21/0337 20130101; H01L 21/266 20130101; H01L
2924/0002 20130101; H01L 2924/00 20130101; H01L 27/1052 20130101;
H01L 21/3205 20130101; H01L 21/76802 20130101; H01L 2924/0002
20130101; H01L 21/31144 20130101 |
Class at
Publication: |
438/675 ;
438/703; 257/E21.585; 257/E21.257 |
International
Class: |
H01L 21/311 20060101
H01L021/311; H01L 21/768 20060101 H01L021/768 |
Claims
1: A method of forming a pattern, comprising: forming a series of
first lines over a first material, the first material being over an
underlying material selected from the group consisting of silicon
nitride, metals, metal comprising compositions and conductively
doped semiconductor materials; forming a series of second lines
over the first lines; the first and second lines forming a
crosshatch pattern over the first material; regions of the first
material being exposed within first openings in the crosshatch
pattern; extending the first openings through the first material;
removing portions of the first lines that are not covered by the
second lines to pattern the first lines into segments; removing the
second lines to uncover the segments; forming masking material
between the segments, the masking material filling the first
openings; removing the segments to form second openings extending
through the masking material to the first material; extending the
second openings through the first material; and removing the
masking material to leave a patterned mask comprising the first
material having the first and second openings therein.
2: The method of claim 1 wherein the first material is over a base,
and further comprising transferring a pattern from the patterned
mask into the base.
3: The method of claim 2 wherein the base comprises an expanse of
silicon nitride over a semiconductor substrate; and wherein the
pattern is transferred into the expanse, and then from the expanse
into one or more materials of the semiconductor substrate.
4: The method of claim 1 further comprising forming electrically
conductive material within the first and second openings of the
patterned mask.
5: The method of claim 1 further comprising forming
anisotropically-etched spacers along sidewalls of the first and
second lines to narrow the first openings prior to extending the
first openings through the first material.
6: The method of claim 1 wherein the first material comprises
amorphous silicon and/or polycrystalline silicon.
7: A method of forming a pattern, comprising: forming stacked first
and second materials over a base, the first material being over an
underlying material selected from the group consisting of silicon
nitride, metals, metal comprising compositions and conductively
doped semiconductor materials, the first and second materials being
of different compositions relative to one another, the second
material being over the first material; patterning the second
material into spaced-apart first lines extending primarily along a
first direction; the first lines and spaces between the first lines
being an undulating topography; forming a third material over the
undulating topography, the third material having a substantially
planar upper surface; patterning the third material into
spaced-apart second lines extending primarily along a second
direction that intersects the first direction; the first and second
lines forming a crosshatch pattern over the first material; regions
of the first material being exposed within first openings in the
crosshatch pattern; forming spacers along sidewalls of the first
and second lines to narrow the first openings in the crosshatch
pattern; extending the narrowed first openings through the first
material; removing the spacers; removing portions of the first
lines that are not covered by the second lines to pattern the first
lines into segments; removing the second lines to uncover the
segments; forming masking material between the segments, the
masking material filling the narrowed first openings; removing the
segments to form second openings extending through the masking
material to the first material; extending the second openings
through the first material; and removing the masking material to
leave a pattern of the second openings and the narrowed first
openings within the first material.
8: The method of claim 7 wherein the second direction is
substantially orthogonal to the first direction.
9: The method of claim 7 wherein the patterning of the second
material comprises forming a photolithographically-patterned
photoresist mask over the second material, and transferring a
pattern from the photoresist mask into the second material.
10: The method of claim 9 wherein the
photolithographically-patterned photoresist mask comprises
spaced-apart features, and further comprising trimming the features
prior to transferring the pattern from the photoresist mask into
the second material.
11: The method of claim 7 wherein the first material consists
essentially of silicon, and wherein the second material comprises
silicon oxynitride.
12: The method of claim 7 wherein the third material is formed over
the undulating topography with a spin-on process.
13: The method of claim 12 wherein the third material is a
carbon-containing material.
14: The method of claim 13 wherein the patterning of the third
material into the second lines comprises forming a hard mask over
the third material, forming a photolithographically-patterned
photoresist mask over the hard mask, transferring a pattern from
the photoresist mask into the hard mask, and transferring a pattern
from the hard mask into the third material.
15: The method of claim 14 wherein the
photolithographically-patterned photoresist mask comprises
spaced-apart features, and further comprising trimming the features
prior to transferring the pattern from the photoresist mask into
the hard mask.
16: The method of claim 14 further comprising trimming the second
lines prior to forming the spacers.
17: The method of claim 7 wherein the spacers comprise silicon
dioxide or silicon nitride.
18: A method of forming a pattern, comprising: forming a first
material over an expanse of underlying material selected from the
group consisting of silicon nitride, metals, metal comprising
compositions and conductively doped semiconductor materials;
forming a second material over the first material, the second
material comprising a different composition from the first
material; patterning the second material into spaced-apart first
lines extending primarily along a first direction; the first lines
and spaces between the first lines being an undulating topography;
depositing third material over the undulating topography with a
spin-on process, the third material having a substantially planar
upper surface; patterning the third material into spaced-apart
second lines extending primarily along a second direction that
intersects the first direction; the first and second lines forming
a crosshatch pattern over the first material; regions of the first
material being exposed within first openings in the crosshatch
pattern; forming spacers along sidewalls of the first and second
lines to narrow the first openings in the crosshatch pattern, the
spacers comprising a different material from the first and second
materials; extending the narrowed first openings through the first
material; removing the spacers; removing portions of the first
lines that are not covered by the second lines to pattern the first
lines into segments; removing the second lines to uncover the
segments; forming masking material between the segments, the
masking material filling the narrowed first openings; removing the
segments to form second openings extending through the masking
material to the first material; extending the second openings
through the first material; and removing the masking material to
leave a repeating pattern comprising the second openings and the
narrowed first openings; said repeating pattern exposing an upper
surface of the expanse.
19: The method of claim 18 wherein the first lines have
sub-lithographic widths.
20: The method of claim 18 wherein the second lines have
sub-lithographic widths.
21: The method of claim 18 wherein the first and second lines have
sub-lithographic widths.
22: The method of claim 18 wherein the masking material is a same
composition as the third material, and is formed utilizing the
spin-on process.
23: The method of claim 22 wherein the third material comprises
carbon.
24: The method of claim 23 wherein the patterning of the third
material into the second lines comprises forming a silicon nitride
hard mask over the third material, forming a
photolithographically-patterned photoresist mask over the hard
mask, transferring a pattern from the photoresist mask into the
hard mask, and transferring a pattern from the hard mask into the
third material.
25: The method of claim 18 wherein the first spaced-apart lines are
on a first pitch, where in the second spaced-apart lines are on the
first pitch, and where the repeating pattern is on a pitch reduced
by a factor of about 2 relative to the first pitch.
26: The method of claim 18 wherein the expanse is over a
semiconductor substrate and comprises silicon nitride; and further
comprising transferring the repeating pattern into the silicon
nitride and then utilizing the patterned silicon nitride for
patterning one or more materials formed over and/or within the
semiconductor substrate.
27: The method of claim 18 wherein the expanse comprises
electrically conductive material, and further comprising forming
one or more electrically conductive materials within the openings
of the repeating pattern and in electrical contact with the
electrically conductive material of the expanse.
28: The method of claim 18 wherein the first material consists
essentially of silicon and the second material consists essentially
of silicon oxynitride.
29: The method of claim 18 wherein the first material consists
essentially of silicon, the second material consists essentially of
silicon oxynitride, and the spacers consist essentially of silicon
dioxide or silicon nitride.
30: The method of claim 29 wherein the forming of the spacers
comprises anisotropically-etching the silicon dioxide or silicon
nitride.
Description
TECHNICAL FIELD
[0001] Methods of forming patterns, and methods of forming
integrated circuitry.
BACKGROUND
[0002] A continuing goal in semiconductor processing is to reduce
the size of individual electronic components, and to thereby enable
smaller and denser integrated circuitry. For instance, it can be
desired to form memory circuitry (such as DRAM, NAND memory, etc.)
to increasingly higher levels of integration.
[0003] A concept commonly referred to as "pitch" can be used to
quantify the density of an integrated circuit pattern. Pitch may be
defined as the distance between an identical point in two
neighboring features of a repeating pattern. Feature size
limitations of a lithographic technique can set a minimum pitch
that can be obtained from the lithographic technique.
[0004] Lithographic processes, such as photolithography, are
commonly utilized during semiconductor processing for fabricating
integrated structures. Lithographic processes have minimum capable
feature sizes, F, which are the smallest feature sizes that can be
reasonably formed with the processes. For instance,
photolithography may be limited by factors such as optics and
radiation wavelength.
[0005] Pitch multiplication, such as pitch-doubling, is a method
for extending the capabilities of lithographic techniques beyond
their minimum pitches. Pitch multiplication may involve forming
sub-lithographic features (i.e., features narrower than minimum
lithographic resolution) by depositing a material to have a
thickness which is less than that of the minimum capable
lithographic feature size, F. The material may be anisotropically
etched to form the sub-lithographic features. The sub-lithographic
features may then be used for integrated circuit fabrication to
create higher density circuit patterns than can be achieved with
conventional lithographic processing.
[0006] It is desired to develop new methods of patterning which are
suitable for fabrication of highly-integrated structures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIGS. 1-60 illustrate a semiconductor construction at
various stages of an example embodiment method of forming a
pattern.
[0008] FIG. 1 shows a top view of the construction, and FIGS. 2-4
show cross-sectional side views along the lines A-A, B-B and C-C of
FIG. 1, respectively.
[0009] FIG. 5 shows a top view of the construction at a processing
stage subsequent to that of FIG. 1, and
[0010] FIGS. 6-8 show cross-sectional side views along the lines
A-A, B-B and C-C of FIG. 5, respectively.
[0011] FIG. 9 shows a top view of the construction at a processing
stage subsequent to that of FIG. 5, and
[0012] FIGS. 10-12 show cross-sectional side views along the lines
A-A, B-B and C-C of FIG. 9, respectively.
[0013] FIG. 13 shows a top view of the construction at a processing
stage subsequent to that of FIG. 9, and
[0014] FIGS. 14-16 show cross-sectional side views along the lines
A-A, B-B and C-C of FIG. 13, respectively.
[0015] FIG. 17 shows a top view of the construction at a processing
stage subsequent to that of FIG. 13, and
[0016] FIGS. 18-20 show cross-sectional side views along the lines
A-A, B-B and C-C of FIG. 17, respectively.
[0017] FIG. 21 shows a top view of the construction at a processing
stage subsequent to that of FIG. 17, and
[0018] FIGS. 22-24 show cross-sectional side views along the lines
A-A, B-B and C-C of FIG. 21, respectively.
[0019] FIG. 25 shows a top view of the construction at a processing
stage subsequent to that of FIG. 21, and
[0020] FIGS. 26-28 show cross-sectional side views along the lines
A-A, B-B and C-C of FIG. 25, respectively.
[0021] FIG. 29 shows a top view of the construction at a processing
stage subsequent to that of FIG. 25, and
[0022] FIGS. 30-32 show cross-sectional side views along the lines
A-A, B-B and C-C of FIG. 29, respectively.
[0023] FIG. 33 shows a top view of the construction at a processing
stage subsequent to that of FIG. 29, and
[0024] FIGS. 34-36 show cross-sectional side views along the lines
A-A, B-B and C-C of FIG. 33, respectively.
[0025] FIG. 37 shows a top view of the construction at a processing
stage subsequent to that of FIG. 33, and
[0026] FIGS. 38-40 show cross-sectional side views along the lines
A-A, B-B and C-C of FIG. 37, respectively.
[0027] FIG. 41 shows a top view of the construction at a processing
stage subsequent to that of FIG. 37, and
[0028] FIGS. 42-44 show cross-sectional side views along the lines
A-A, B-B and C-C of FIG. 41, respectively.
[0029] FIG. 45 shows a top view of the construction at a processing
stage subsequent to that of FIG. 41, and
[0030] FIGS. 46-48 show cross-sectional side views along the lines
A-A, B-B and C-C of FIG. 45, respectively.
[0031] FIG. 49 shows a top view of the construction at a processing
stage subsequent to that of FIG. 45, and
[0032] FIGS. 50-52 show cross-sectional side views along the lines
A-A, B-B and C-C of FIG. 49, respectively.
[0033] FIG. 53 shows a top view of the construction at a processing
stage subsequent to that of FIG. 49, and
[0034] FIGS. 54-56 show cross-sectional side views along the lines
A-A, B-B and C-C of FIG. 53, respectively.
[0035] FIG. 57 shows a top view of the construction at a processing
stage subsequent to that of FIG. 53, and
[0036] FIGS. 58-60 show cross-sectional side views along the lines
A-A, B-B and C-C of FIG. 57, respectively.
[0037] FIG. 61 shows an expanded view of a region labeled "D" in
FIG. 57.
[0038] FIG. 62 shows the construction of FIG. 59 at a processing
stage subsequent to that of FIG. 59 in accordance with an example
embodiment method.
[0039] FIG. 63 shows the construction of FIG. 59 at a processing
stage subsequent to that of FIG. 59 in accordance with another
example embodiment method.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0040] Some embodiments comprise methods of forming patterns in
which a second series of lines is overlaid across a first series of
lines to form a grid. Such grid may be utilized to define a
repeating pattern, and such a pattern may be utilized to fabricate
an array of highly-integrated integrated circuitry, such as a DRAM
array, a NAND memory array, etc.
[0041] Example embodiments are described with reference to FIGS.
1-63.
[0042] Referring to FIGS. 1-4, a semiconductor construction 10 is
shown in top view (FIG. 1) and cross-sectional side views (FIGS.
2-4). The construction comprises a base 12 and a stack 14 of
materials 16, 18 and 20 over the base.
[0043] The base may comprise, consist essentially of, or consist of
monocrystalline silicon, and may be referred to as a semiconductor
substrate, or as a portion of a semiconductor substrate. The terms
"semiconductive substrate," "semiconductor construction" and
"semiconductor substrate" mean any construction comprising
semiconductive material, including, but not limited to, bulk
semiconductive materials such as a semiconductive wafer (either
alone or in assemblies comprising other materials), and
semiconductive material layers (either alone or in assemblies
comprising other materials). The term "substrate" refers to any
supporting structure, including, but not limited to, the
semiconductive substrates described above. In some embodiments, the
base may correspond to a semiconductor substrate containing one or
more materials associated with integrated circuit fabrication. In
such embodiments, such materials may correspond to one or more of
refractory metal materials, barrier materials, diffusion materials,
insulator materials, etc.
[0044] The materials 16, 18 and 20 may be selectively etchible
relative to one another, and may comprise any suitable materials.
For purposes of interpreting this disclosure and the claims that
follow, a first material is considered to be "selectively etchible"
relative to a second material if etching conditions may be chosen
which remove the first material at a faster rate than the second
material; which can include, but is not limited to, embodiments in
which the first material is removed under conditions which are 100
percent selective for the first material relative to the second
material.
[0045] In some embodiments, material 16 may be electrically
insulative material which is ultimately patterned into a hard mask
suitable for forming an integrated circuit pattern which extends
into base 12 (as discussed below with reference to FIG. 63). In
such embodiments, material 16 may comprise, consist essentially of,
or consist of, for example, silicon nitride. In some embodiments,
material 16 may be an electrically conductive material which
ultimately supports electrically conductive contacts formed
thereover (as discussed below with reference to FIG. 62). In such
embodiments, material 16 may comprise, consist essentially of, or
consist of, for example, one or more of various metals (e.g.,
copper, aluminum, tungsten, titanium, etc.), metal-containing
compositions (e.g., metal nitrides, metal carbides, metal
silicides, etc.), and conductively-doped semiconductor materials
(e.g., conductively-doped silicon, conductively-doped germanium,
etc.). In some embodiments, the material 16 may be considered to be
an expanse which extends across at least a portion of base 12.
[0046] In some embodiments, material 18 may comprise, consist
essentially of, or consist of silicon. For instance, material 18
may consist essentially of one or both of polycrystalline silicon
and amorphous silicon.
[0047] In some embodiments, material 20 may comprise silicon
oxynitride (e.g., a deposited antireflective composition (DARC)).
In some embodiments, the silicon oxynitride maybe oxygen
enriched.
[0048] The materials 16, 18 and 20 may be formed to any suitable
thicknesses, and in some embodiments the individual materials may
be formed to thicknesses of from about 50 .ANG. to about 1000
.ANG..
[0049] In some embodiments, materials 18 and 20 are utilized to
form a pattern which is ultimately transferred into one or more
structures underlying the materials (for instance, the structures
underlying materials 18 and 20 include the material 16 and the base
12 in the shown embodiment). In some embodiments, materials 18 and
20 may be referred to as stacked first and second materials,
respectively, which are of different compositions relative to one
another.
[0050] Patterned photoresist 22 is formed over the stack 14. The
patterned photoresist may be formed utilizing photolithography, and
in some embodiments may be referred to as a
photolithographically-patterned photoresist mask. The patterned
photoresist is configured as a plurality of spaced apart lines 24
(which may be referred to as features in some embodiments)
extending across an upper surface of material 20. In the shown
embodiment, the lines 24 extend primarily along a direction of an
axis 5. Although the lines 24 are illustrated to be straight, in
other embodiments the lines may be curved or wavy.
[0051] Referring next to FIGS. 5-8, the photoresist lines 24 are
subjected to trimming to reduce widths of the lines. Although the
tops of the lines 24 are shown to be unaffected by the trimming, in
some embodiments the trimming conditions may decrease the heights
of the lines and/or may induce other changes to the lines (e.g.,
may impose a dome-shape to the lines). For instance, trimming
conditions may be chosen which isotropically etch the lines. The
trimming of the lines may be omitted in some embodiments. If the
trimming is utilized, such trimming may be accomplished with any
suitable processing; including, for example, plasma etching with an
inductively coupled reactor.
[0052] In some embodiments, the trimmed lines 24 at the processing
stage of FIGS. 5-8 may have sub-lithographic widths. In some
embodiments, the initial photoresist lines 24 formed at the
processing stage of FIGS. 1-4 have widths of at least about 40
nanometers (nm), and the trimmed lines 24 at the processing stage
of FIGS. 5-8 have widths of less than 40 nm, less than 20 nm,
etc.
[0053] Referring next to FIGS. 9-12, the pattern of trimmed
photoresist lines 24 (FIGS. 5-8) is transferred into material 20,
and subsequently the photoresist lines are removed. The patterning
of material 20 forms material 20 into a series of lines 26 over an
upper surface of material 18, with the individual lines extending
along the direction of axis 5. The lines 26 are spaced-apart from
one another by spaces 28. The lines 26 and spaces 28 together
define an undulating topography of construction 10.
[0054] Referring next to FIGS. 13-16, a material 30 is formed
across the undulating topography of lines 26 and spaces 28. The
material 30 may be a spin-on material, and may be deposited to a
suitable thickness and under appropriate conditions to form the
shown planarized surface 31 above lines 26. In some embodiments,
material 30 may comprise one or more organic polymers, and
accordingly may be a carbon-containing spin-on material. In some
embodiments, material 30 may comprise other compositions besides
spin-on compositions, and the planarized surface 31 may be formed
by chemical-mechanical polishing (CMP) or other suitable
planarization.
[0055] In some embodiments, material 30 may be referred to as a
third material to distinguish it from the above-discussed first and
second materials 18 and 20. In some embodiments, material 30 may be
about twice as thick as material 20.
[0056] A hard mask material 32 is formed over surface 31, and
patterned photoresist 34 is formed over the hard mask material. The
patterned photoresist may be formed utilizing photolithography, and
in some embodiments may be referred to as a
photolithographically-patterned photoresist mask. The patterned
photoresist is configured as a plurality of spaced-apart lines 36
(which may be referred to as features in some embodiments)
extending across an upper surface of hard mask material 32. In the
shown embodiment, the lines 36 extend primarily along a direction
of an axis 7. The axis 7 intersects the axis 5 (described above in
FIGS. 1-4). In the shown embodiment, axis 7 is substantially
orthogonal to axis 5; with the term "substantially orthogonal"
meaning that the axes are orthogonal to within reasonable
tolerances of fabrication and measurement. In other embodiments,
axis 7 may not be substantially orthogonal to axis 5, and
accordingly may intersect axis 5 at an angle other than about
90.degree..
[0057] Although the lines 36 are illustrated to be straight, in
other embodiments the lines may be curved or wavy.
[0058] The hard mask material 32 may comprise any suitable
composition or combination of compositions, and in some embodiments
may comprise, consist essentially of, or consist of silicon
nitride, silicon oxynitride, etc.
[0059] Referring next to FIGS. 17-20, the pattern of photoresist
lines 36 (FIGS. 13-16) is transferred through hard mask material 32
(FIGS. 13-16) and into material 30, and subsequently the hard mask
material and photoresist lines are removed. The patterning of
material 30 forms material 30 into a series of lines 38 extending
over lines 26 and across an upper surface of the material 18, with
the individual lines 38 extending along the direction of axis 7. In
some embodiments, the lines 38 may be about twice as tall as the
lines 26.
[0060] In some embodiments, the photoresist lines 36 (FIGS. 13-16)
may be trimmed with processing analogous to that of FIGS. 5-8 prior
to transferring the pattern of the photoresist lines into material
30. Accordingly, the lines 38 may have sub-lithographic widths at
the processing stage of FIGS. 17-20.
[0061] Referring next to FIGS. 21-24, the lines 38 are subjected to
trimming to reduce widths of the lines. Although the tops of the
lines 38 are shown to be unaffected by the trimming, in some
embodiments the trimming conditions may decrease the heights of the
lines and/or may induce other changes to the lines (e.g., may
impose a dome-shape to the lines). For instance, trimming
conditions may be chosen which isotropically etch the lines. The
trimming of the lines may be omitted in some embodiments. If the
trimming is utilized, and the lines 38 comprise organic material,
such trimming may be accomplished utilizing, for example, plasma
etching with an inductively coupled reactor.
[0062] In some embodiments, the lines 38 at the processing stage of
FIGS. 21-24 have widths of less than 40 nm, less than 20 nm, etc.
In some embodiments, the trimmed lines 38 at the processing stage
of FIGS. 21-24 may have sub-lithographic widths. In some
embodiments, the trimming shown in FIGS. 21-24 may be omitted. In
some embodiments, the photoresist lines 36 of FIGS. 13-16 may be
trimmed additionally, or alternatively, to trimming the lines 38 of
material 30.
[0063] In some embodiments, the lines 26 of material 20 may be
referred to as first lines, and the lines 38 of material 30 may be
referred to as second lines. Such first and second lines form a
crosshatch pattern (or lattice) over material 18. Openings 40 (only
some of which are labeled) extend through the crosshatch pattern,
with such openings exposing regions of material 18.
[0064] In the shown embodiment, the first and second lines 26 and
38 are both on about the same pitch, P.sub.1, and are orthogonal to
one another. Accordingly, the openings 40 are substantially square.
In other embodiments, the lines 38 may be at an angle which is
other than orthogonal relative to the lines 26, and/or the lines 38
may be on a different pitch than the lines 26. Accordingly, the
openings may be rectangular in some embodiments, and may be of
other polygonal shapes besides square or rectangular in yet other
embodiments. In some embodiments, the lines 26 and/or 38 may be
curved or wavy, and thus at least some of the openings may have
curved shapes.
[0065] In the shown embodiment the lines 38 have about the same
widths as the lines 26, but in other embodiments the lines 38 may
have different widths than the lines 26. In the shown embodiment,
all of the openings 40 are about the same size and shape as one
another. However, in some embodiments the lines 26 may be arranged
in a pattern other than the shown uniform pitch, and/or the lines
38 may be arranged in a pattern other than the shown uniform pitch,
which can enable openings 40 to be formed in a repeating pattern
with some of the openings being larger and/or differently shaped
than others.
[0066] Referring next to FIGS. 25-28, spacer material 42 (only some
of which is labeled) is provided along and over the first and
second lines 26 and 38, and then anisotropically etched to form
spacers 44 (only some which are labeled). The spacers narrow the
openings 40.
[0067] The spacer material 42 may comprise any suitable composition
or combination of compositions; and in some embodiments may
comprise, consist essentially of, or consist of silicon dioxide or
silicon nitride.
[0068] Referring to FIGS. 29-32, the narrowed openings 40 are
extended through material 18 to expose an upper surface of material
16. As discussed above, in some embodiments material 18 comprises
silicon (e.g., polycrystalline and/or amorphous silicon), and
material 16 comprise silicon nitride. Accordingly, in some
embodiments the narrowed openings 40 are extended through a
silicon-containing material to expose an upper surface of a silicon
nitride-containing material. In some embodiments material 16 may be
referred to as an expanse under material 18, and in such
embodiments the narrowed openings may be considered to be extended
through material 18 to expose an upper surface of the expanse. The
openings 40 may be extended through material 18 with any suitable
processing, including, for example, utilization of a plasma
etch.
[0069] Referring next to FIGS. 33-36, the spacers 44 (FIGS. 29-32)
are removed with an etch selective for the spacer material 42
(FIGS. 29-32) relative to materials 16, 18, 20 and 30. For purposes
of interpreting this disclosure and the claims that follow, a first
material is considered to be "selectively removed" relative to a
second material if the first material is removed at a faster rate
than the second material; which can include, but is not limited to,
embodiments in which the first material is removed under conditions
which are 100 percent selective for the first material relative to
the second material. In some embodiments, the spacer material
consists of silicon dioxide, material 16 consists of silicon
nitride, material 18 consists of silicon, material 20 consists of
silicon oxynitride, and material 30 consists of an organic
polymer.
[0070] Referring next to FIGS. 37-40, exposed portions of material
20 are removed selectively relative to material 16, 18 and 30. Such
removes portions of lines 26 (FIGS. 33-36) while leaving segments
48 of the lines 26 underneath the lines 38 of material 30. The
cross-section of FIG. 40 shows some segments 48 of lines 26 under
one of the lines 38 of material 30.
[0071] Referring next to FIGS. 41-44, the lines 38 of material 30
(FIGS. 37-40) are removed to uncover the segments 48 of material
20. In the shown embodiment, the segments 48 are pedestals having
about the same dimensions as openings 40. In other embodiments, the
pedestals may have other dimensions and/or shapes than openings
40.
[0072] The top view of FIG. 41 shows that the segments 48 (i.e.,
the segments of material 20) and the openings 40 together form a
repeating pattern across the construction 10. The processing of
FIGS. 45-60 aligns openings in material 18 to the locations of the
segments 48.
[0073] Referring to FIGS. 45-48, a masking material 50 is formed
between the segments 48. The masking material fills the openings
40, and leaves upper surfaces of the segments 48 exposed. The
material 50 comprises a composition to which material 20 may be
selectively removed, and may comprise any suitable substance. In
some embodiments, the masking material 50 may comprise a spin-on
carbon-containing material, and may be identical to the material 30
described above with reference to FIGS. 13-16. The material 50 may
be formed in the shown configuration by initially forming material
50 to cover the segments 48, and then utilizing CMP or other
suitable planarization to remove excess material 50 from over the
segments 48; and/or utilizing a plasma etch to remove the excess
material 50.
[0074] Referring next to FIGS. 49-52, the segments 48 (FIGS. 45-48)
are removed selectively relative to material 50 to leave openings
52 extending through material 50 to an upper surface of material
18.
[0075] Referring to FIGS. 53-56, the openings 52 are extended
through material 18 to an upper surface of material 16. The
openings 52 may be extended through material 18 with any suitable
processing, including, for example, utilization of a plasma
etch.
[0076] Referring to FIGS. 57-60, the masking material 50 (FIGS.
53-56) is removed. The remaining material 18 is a patterned mask 60
having openings 40 and 52 extending therethrough. The openings 40
and 52 may be referred to as first and second openings,
respectively. In the shown embodiment, such first and second
openings are about the same size and shape as one another, but in
other embodiments the second openings may be different sizes and/or
shapes than the first openings. In the shown embodiment, the first
and second openings are approximately square-shaped. In other
embodiments, the openings may have other shapes, including
rectangular shapes, other polygonal shapes, circular shapes,
elliptical shapes, other curved shapes, etc. In the shown
embodiment, the first openings 40 are all approximately the same
size and shape as one another. As discussed above with reference to
FIGS. 21-24, in other embodiments some of the openings 40 may be of
different size and/or shapes relative to others of such openings.
Thus, the patterned mask 60 may comprise the dense repeating
pattern illustrated in FIGS. 57-60, or may comprise other patterns
in other embodiments.
[0077] In some embodiments, the pattern of openings 40 and 52 of
FIGS. 57-60 may be considered to be suitable for fabrication of a
cross-point array of integrated structures. Such pattern may be
tailored for particular applications by adjusting various aspects
of the pattern including, for example, sizes of the openings,
shapes of the openings, spacings between the openings, pitch
regularity, etc.
[0078] FIG. 61 shows an expanded region "D" of FIG. 57 and shows
that the illustrated dense pattern of mask 60 may have a pitch
P.sub.2 which is reduced relative to the pitch P.sub.1 of the lines
26 and 38 of FIGS. 21-24. In the shown embodiment, the pitch
P.sub.2 is reduced relative to P.sub.1 by a factor of about {square
root over (2)}.
[0079] In subsequent processing, the patterned mask 60 may be
utilized for patterning integrated circuitry. For instance, FIG. 62
shows a construction 10a at a processing stage subsequent to that
of FIG. 59. The construction 10a comprises electrically conductive
material 16, and the mask 60 is utilized for patterning a material
70 into electrically conductive interconnects that extend to the
conductive material 16. As another example, FIG. 63 shows a
construction 10b at a processing stage subsequent to that of FIG.
59 in which the openings 40 are extended through material 16 to
upper surface of base 12. In subsequent processing, one or more
materials may be formed within openings 40 during fabrication of
integrated circuitry supported by base 12, and/or openings 40 may
be extended into one or more materials of base 12, and/or one or
more dopants may be implanted through openings 40 and into base 12.
In some embodiments, the patterned mask 60 may be utilized for
fabricating one or more components of highly-integrated memory
circuitry; such as, for example, DRAM, NAND memory, etc.
[0080] The particular orientation of the various embodiments in the
drawings is for illustrative purposes only, and the embodiments may
be rotated relative to the shown orientations in some applications.
The description provided herein, and the claims that follow,
pertain to any structures that have the described relationships
between various features, regardless of whether the structures are
in the particular orientation of the drawings, or are rotated
relative to such orientation.
[0081] The cross-sectional views of the accompanying illustrations
only show features within the planes of the cross-sections, and do
not show materials behind the planes of the cross-sections in order
to simplify the drawings.
[0082] When a structure is referred to above as being "on" or
"against" another structure, it can be directly on the other
structure or intervening structures may also be present. In
contrast, when a structure is referred to as being "directly on" or
"directly against" another structure, there are no intervening
structures present. When a structure is referred to as being
"connected" or "coupled" to another structure, it can be directly
connected or coupled to the other structure, or intervening
structures may be present. In contrast, when a structure is
referred to as being "directly connected" or "directly coupled" to
another structure, there are no intervening structures present.
[0083] Some embodiments include a method of forming a pattern. A
series of first lines are formed over a first material. A series of
second lines are formed over the first lines. The first and second
lines form a crosshatch pattern over the first material. Regions of
the first material are exposed within first openings in the
crosshatch pattern. The first openings are extended through the
first material. Portions of the first lines that are not covered by
the second lines are removed to pattern the first lines into
segments. The second lines are removed to uncover the segments.
Masking material is formed between the segments. The masking
material fills the first openings. The segments are removed to form
second openings extending through the masking material to the first
material. The second openings are extended through the first
material. The masking material is removed to leave a patterned mask
comprising the first material having the first and second openings
therein.
[0084] Some embodiments include a method of forming a pattern.
Stacked first and second materials are formed over a base. The
first and second materials are of different compositions relative
to one another. The second material is over the first material. The
second material is patterned into spaced-apart first lines
extending primarily along a first direction. The first lines and
spaces between the first lines define an undulating topography. A
third material is formed over the undulating topography. The third
material has a substantially planar upper surface. The third
material is patterned into spaced-apart second lines extending
primarily along a second direction that intersects the first
direction. The first and second lines form a crosshatch pattern
over the first material. Regions of the first material are exposed
within first openings in the crosshatch pattern. Spacers are formed
along sidewalls of the first and second lines to narrow the first
openings in the crosshatch pattern. The narrowed first openings are
extended through the first material. The spacers are removed.
Portions of the first lines that are not covered by the second
lines are removed to pattern the first lines into segments. The
second lines are removed to uncover the segments. Masking material
is formed between the segments. The masking material fills the
narrowed first openings. The segments are removed to form second
openings that extend through the masking material to the first
material. The second openings are extended through the first
material. The masking material is removed to leave a pattern of the
second openings and the narrowed first openings within the first
material.
[0085] Some embodiments include a method of forming a pattern. A
first material is formed over an expanse. A second material is
formed over the first material. The second material comprises a
different composition from the first material. The second material
is patterned into spaced-apart first lines extending primarily
along a first direction. The first lines and spaces between the
first lines define an undulating topography. Third material is
deposited over the undulating topography with a spin-on process.
The third material has a substantially planar upper surface. The
third material is patterned into spaced-apart second lines
extending primarily along a second direction that intersects the
first direction. The first and second lines form a crosshatch
pattern over the first material. Regions of the first material are
exposed within first openings in the crosshatch pattern. Spacers
are formed along sidewalls of the first and second lines to narrow
the first openings in the crosshatch pattern. The spacers comprise
a different material from the first and second materials. The
narrowed first openings are extended through the first material.
The spacers are removed. Portions of the first lines that are not
covered by the second lines are removed to pattern the first lines
into segments. The second lines are removed to uncover the
segments. Masking material is formed between the segments. The
masking material fills the narrowed first openings. The segments
are removed to form second openings that extend through the masking
material to the first material. The second openings are extended
through the first material. The masking material is removed to
leave a repeating pattern comprising the second openings and the
narrowed first openings. The repeating pattern exposes an upper
surface of the expanse.
[0086] In compliance with the statute, the subject matter disclosed
herein has been described in language more or less specific as to
structural and methodical features. It is to be understood,
however, that the claims are not limited to the specific features
shown and described, since the means herein disclosed comprise
example embodiments. The claims are thus to be afforded full scope
as literally worded, and to be appropriately interpreted in
accordance with the doctrine of equivalents.
* * * * *