U.S. patent application number 14/674127 was filed with the patent office on 2016-10-06 for methods of fabricating features associated with semiconductor substrates.
This patent application is currently assigned to Micron Technology, Inc.. The applicant listed for this patent is Micron Technology, Inc.. Invention is credited to Gurtej S. Sandhu, Scott E. Sills.
Application Number | 20160293433 14/674127 |
Document ID | / |
Family ID | 57006272 |
Filed Date | 2016-10-06 |
United States Patent
Application |
20160293433 |
Kind Code |
A1 |
Sills; Scott E. ; et
al. |
October 6, 2016 |
Methods of Fabricating Features Associated With Semiconductor
Substrates
Abstract
Some embodiments include a method of fabricating features
associated with a semiconductor substrate. A first region of the
semiconductor substrate is altered relative to a second region. The
altered first region has different physisorption characteristics
for polynucleotide relative to the second region. The altered first
region and the second region are exposed to polynucleotide. The
polynucleotide selectively adheres to either the altered first
region or the second region to form a polynucleotide mask. The
polynucleotide mask is used during fabrication of features
associated with the semiconductor substrate.
Inventors: |
Sills; Scott E.; (Boise,
ID) ; Sandhu; Gurtej S.; (Boise, ID) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Micron Technology, Inc. |
Boise |
ID |
US |
|
|
Assignee: |
Micron Technology, Inc.
|
Family ID: |
57006272 |
Appl. No.: |
14/674127 |
Filed: |
March 31, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/3086 20130101;
H01L 21/0271 20130101; H01L 21/266 20130101; H01L 21/3081
20130101 |
International
Class: |
H01L 21/308 20060101
H01L021/308 |
Claims
1. (canceled)
2. A method of fabricating features associated with a semiconductor
substrate, comprising: altering surface potential characteristics
of a first region of the semiconductor substrate relative to a
second region; the altered first region having different
physisorption characteristics for polynucleotide relative to the
second region; exposing the altered first region and the second
region to polynucleotide; the polynucleotide selectively adhering
to either the altered first region or the second region to form a
polynucleotide mask; using the polynucleotide mask during
fabrication of features associated with the semiconductor
substrate; and wherein the using of the polynucleotide mask during
fabrication of the features includes etching into the semiconductor
substrate while using the polynucleotide mask to define a pattern
for the etch.
3. (canceled)
4. A method of fabricating features associated with a semiconductor
substrate, comprising: altering surface potential characteristics
of a first region of the semiconductor substrate relative to a
second region; the altered first region having different
physisorption characteristics for polynucleotide relative to the
second region; exposing the altered first region and the second
region to polynucleotide; the polynucleotide selectively adhering
to either the altered first region or the second region to form a
polynucleotide mask; using the polynucleotide mask during
fabrication of features associated with the semiconductor
substrate; wherein the surface potential characteristics are
altered by providing an electrical bias to at least one of the
first and second regions; and wherein wiring is provided along the
first region, and wherein the electrical bias is provided along the
wiring to selectively adhere the polynucleotide to the wiring
relative to the second region of the substrate or to selectively
repel polynucleotide from the wiring relative to the second region
of the substrate.
5. The method of claim 4 wherein the wiring comprises one or more
materials formed over the substrate.
6. The method of claim 4 wherein the wiring comprises dopant
implanted into the substrate.
7. A method of fabricating features associated with a semiconductor
substrate, comprising: altering surface potential characteristics
of a first region of the semiconductor substrate relative to a
second region; the altered first region having different
physisorption characteristics for polynucleotide relative to the
second region; exposing the altered first region and the second
region to polynucleotide; the polynucleotide selectively adhering
to either the altered first region or the second region to form a
polynucleotide mask; using the polynucleotide mask during
fabrication of features associated with the semiconductor
substrate; and wherein the surface potential characteristics are
altered utilizing a corona discharge to selectively alter surface
potential characteristic of the first region relative to the second
region.
8. A method of fabricating features associated with a semiconductor
substrate, comprising: altering surface potential characteristics
of a first region of the semiconductor substrate relative to a
second region; the altered first region having different
physisorption characteristics for polynucleotide relative to the
second region; exposing the altered first region and the second
region to polynucleotide; the polynucleotide selectively adhering
to either the altered first region or the second region to form a
polynucleotide mask; using the polynucleotide mask during
fabrication of features associated with the semiconductor
substrate; wherein the surface potential characteristics are
altered by providing an electrical bias to at least one of the
first and second regions; and wherein insulative material extends
across the first and second regions; and wherein the surface
potential characteristics of the first region are altered by
providing conductive material across the first region and
subsequently applying the electrical bias to the conductive
material.
9. The method of claim 8 wherein the conductive material includes
an oriented molecular arrangement.
10. The method of claim 8 wherein the conductive material includes
conductively-doped semiconductor material.
11. A method of fabricating features associated with a
semiconductor substrate, comprising: providing dopant into a first
region of the semiconductor substrate to alter the first region
relative to a second region; the altered first region having
different physisorption characteristics for polynucleotide relative
to the second region; exposing the altered first region and the
second region to polynucleotide; the polynucleotide selectively
adhering to either the altered first region or the second region to
form a polynucleotide mask; and using the polynucleotide mask
during fabrication of features associated with the semiconductor
substrate.
12. The method of claim 11 wherein the using of the polynucleotide
mask during fabrication of the features includes one or more of
incorporating at least some of the polynucleotide mask into an
integrated assembly, etching into the semiconductor substrate while
using the polynucleotide mask to define a pattern for the etch, and
adhering one or more materials to the polynucleotide mask to
pattern said one or more materials.
13. The method of claim 11 wherein said providing of the dopant
comprises implanting the dopant into the first region.
14. The method of claim 11 wherein said providing of the dopant
comprises implanting the dopant into the first region utilizing
shallow ion implantation and/or plasma doping (PLAD).
15. The method of claim 11 wherein the first and second regions
comprise semiconductor material of the semiconductor substrate.
16. The method of claim 11 wherein the first and second regions
comprise a second material formed over semiconductor material of
the semiconductor substrate.
17. The method of claim 16 wherein the second material is
insulative.
18. The method of claim 16 wherein the second material is
conductive.
19. The method of claim 11 wherein the dopant is initially within a
layer formed across the first region, and is provided into the
first region by transferring the dopant from the layer into the
first region.
20. A method of fabricating features associated with a
semiconductor substrate, comprising: depositing a material across a
first region of the semiconductor substrate to alter the first
region relative to a second region; the altered first region having
different physisorption characteristics for polynucleotide relative
to the second region; the depositing incorporating components
within the material that alter the physisorption characteristics of
the material for the polynucleotide; exposing the altered first
region and the second region to polynucleotide; the polynucleotide
selectively adhering to either the altered first region or the
second region to form a polynucleotide mask; and using the
polynucleotide mask during fabrication of features associated with
the semiconductor substrate.
21. The method of claim 20 wherein the using of the polynucleotide
mask during fabrication of the features includes one or more of
incorporating at least some of the polynucleotide mask into an
integrated assembly, etching into the semiconductor substrate while
using the polynucleotide mask to define a pattern for the etch, and
adhering one or more materials to the polynucleotide mask to
pattern said one or more materials.
22. The method of claim 20 wherein the depositing comprises one or
both of atomic layer deposition or chemical vapor deposition.
23. The method of claim 20 wherein the material is insulative.
24. The method of claim 20 wherein the material is conductive.
25. The method of claim 20 wherein the components include one or
more of organometallics, hydrogen, and organo-alkaline earth
compounds.
26. The method of claim 20 wherein the components include one or
both of calcium and magnesium.
27. The method of claim 20 wherein the components include trapped
charges.
28. A method of fabricating features associated with a
semiconductor substrate, comprising: forming a material across a
first region of the semiconductor substrate to alter the first
region relative to a second region; the altered first region having
different physisorption characteristics for polynucleotide relative
to the second region; the forming of the material comprising
orienting a molecular arrangement relative to a surface of the
semiconductor substrate; the molecular arrangement comprising a
brush layer formed along a surface of the first region, or a
self-assembling pattern formed along the surface of the first
region; exposing the altered first region and the second region to
polynucleotide; the polynucleotide selectively adhering to either
the altered first region or the second region to form a
polynucleotide mask; and using the polynucleotide mask during
fabrication of features associated with the semiconductor
substrate.
29. The method of claim 28 wherein the using of the polynucleotide
mask during fabrication of the features includes one or more of
incorporating at least some of the polynucleotide mask into an
integrated assembly, etching into the semiconductor substrate while
using the polynucleotide mask to define a pattern for the etch, and
adhering one or more materials to the polynucleotide mask to
pattern said one or more materials.
30. The method of claim 28 wherein the molecular arrangement
comprises the brush layer.
31. The method of claim 28 wherein the molecular arrangement
comprises the self-assembling pattern.
32. The method of claim 28 wherein the molecular arrangement
comprises negatively-charged terminal groups to repel the
polynucleotide.
33. The method of claim 28 wherein the molecular arrangement
comprises positively-charged terminal groups to attract the
polynucleotide.
34. The method of claim 28 wherein the molecular arrangement
comprises poly(dimethylamino)ethyl methacrylate.
35. The method of claim 28 wherein the molecular arrangement
comprises a coordinated transition metal.
Description
TECHNICAL FIELD
[0001] Methods of fabricating features associated with
semiconductor substrates.
BACKGROUND
[0002] A variety of methods have been developed for creating
patterned masks suitable for patterning underlying materials during
fabrication of integrated circuitry. A continuing goal of
integrated circuit fabrication is to increase integrated circuit
density, and accordingly to decrease the size of individual
integrated circuit components. There is thus a continuing goal to
form patterned masks having reduced feature sizes.
[0003] A typical patterned mask utilized for integrated circuit
fabrication is photolithographically-patterned photoresist. Such
may be utilized to form feature sizes approaching about 40
nanometers (nm). Sublithographic feature sizes may be formed
utilizing pitch-multiplication methodologies (which reduce pitch
size by a given multiple; for instance, pitch-doubling methodology
reduces pitch size by a multiple of two). However,
pitch-multiplication methodologies may be costly due to the
complexities associated with such methodologies. Another method
showing promise for creating sublithographic feature sizes involves
self-assembly of block copolymer to form repeating patterns.
Unfortunately, there is often poor control of the final pattern
created with the block copolymer. Accordingly, there may be too
many defects remaining in the final pattern for commercial
viability.
[0004] It is desirable to develop new methods for patterning
sublithographic features suitable for semiconductor
fabrication.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIGS. 1-27 are diagrammatic cross-sectional views of example
constructions at process stages of example methods.
[0006] FIG. 2A is a top view of the construction of FIG. 2, with
the view of FIG. 2 being along the line 2-2 of FIG. 2A.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0007] Polymer which may be utilized to form patterns with a high
degree of specificity is polynucleotide (for instance,
deoxyribonucleic acid [DNA], ribonucleic acid [RNA], etc.). In some
embodiments, methods are developed for selective physisorption of
polynucleotide on one region of a semiconductor substrate relative
to another during fabrication of features associated with the
semiconductor substrate. In some embodiments the features may be
sublithographic, and may have dimensions much smaller than 40 nm;
such as, for example, dimensions of less than or equal to about 10
nm, less than or equal to about 5 nm, etc.
[0008] For purposes of interpreting this disclosure and the claims
that follow, the term "polynucleotide" means a polymer comprising
two or more nucleotides. There is some historic distinction between
polymers referred to as "polynucleotide" and polymers referred to
as "oligonucleotide", with both comprising the same subunits and
"polynucleotides" being understood to be longer than
"oligonucleotides". For purposes of interpreting this disclosure
and the claims that follow, the term "polynucleotide" is used to
encompass all polymer lengths, and accordingly to generically
encompass polymer lengths sometimes referred to in the art as
"oligonucleotides", as well as the longer polymer lengths.
[0009] The term "physisorption" as used herein is generic for any
non-covalent mechanism of adsorption, attraction or adhesion;
including, for example, van der Waals interactions, ionic bonding
interactions, hydrogen bonding interactions, electrostatic
interactions, etc.
[0010] Example embodiments are described with reference to FIGS.
1-27.
[0011] Referring to FIG. 1, a construction 10 comprises a
semiconductor substrate 12. The term "semiconductor substrate"
means 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 semiconductor substrates described above. The semiconductor
substrate 12 may comprise any suitable semiconductor material, and
in some embodiments may comprise, consist essentially of, or
consist of monocrystalline silicon.
[0012] In some embodiments, semiconductor substrate 12 may comprise
one or more materials associated with integrated circuit
fabrication. Some of the materials may be under the shown region of
semiconductor substrate 12 and/or may be laterally adjacent the
shown region of semiconductor substrate 12; and may correspond to,
for example, one or more of refractory metal materials, barrier
materials, diffusion materials, insulator materials, etc.
[0013] The semiconductor substrate 12 is shown comprising a first
region 14 and a second region 16. The first and second regions have
uppermost surfaces 15 and 17, respectively. In some embodiments, it
is desired to form a polynucleotide mask across one of the first
and second regions selectively relative to the other of the first
and second regions. For instance, in some embodiments a memory
array is formed across one of the first and second regions, while
peripheral circuitry is formed across the other of the first and
second regions. The polynucleotide mask may be utilized for
fabricating densely-spaced components of the memory array.
Accordingly, it may be desired to form the polynucleotide mask
across the memory array region, but not across the peripheral
region. In other embodiments, the polynucleotide mask may be
utilized for selectively fabricating peripheral circuitry relative
to memory array circuitry; or for other applications. Regardless,
it is desired to selectively form the polynucleotide mask so that
it is on one of the regions 14 and 16, and not the other.
[0014] In some embodiments, one of the regions 14 and 16 is treated
so that such region has different physisorption characteristics for
polynucleotide relative to the other of the regions 14 and 16. The
treatment may comprise one or more of a dopant implant, provision
of electrical bias, formation of a molecular arrangement with
positively-charged terminal groups or negatively-charged terminal
groups, etc. Various example embodiments for altering physisorption
characteristics of a region of a semiconductor substrate are
described with more specificity with reference to FIGS. 10-27. The
polynucleotide over a region of a semiconductor substrate may be
utilized for fabricating features, and example methods of such
feature fabrication are described with reference to FIGS. 2-9.
[0015] FIG. 2 shows construction 10 at a processing stage after one
of the regions 14 and 16 is treated to alter its physisorption
characteristics for polynucleotide relative to the other region,
and after exposure to polynucleotide 18 under suitable conditions
for physisorption. Such conditions may include, for example,
appropriate pH, ionic strength, etc. In the shown embodiment, the
polynucleotide selectively adheres to the surface 15 of region 14
relative to the surface 17 of region 16 due to the different
physisorption characteristics of the regions.
[0016] The illustrated polynucleotide self-assembles into a pattern
comprising spaces 20. Such pattern is further illustrated in a top
view of FIG. 2A (only some of the spaces 20 are labeled in the top
view of FIG. 2A).
[0017] The polynucleotide may comprise any suitable composition for
achieving the desired self-assembly. For instance, the
polynucleotide may correspond to DNA, and the self-assembly may
occur through DNA origami assembly, DNA canvas assembly (i.e.,
assemblies comprising DNA tiles), etc. As another example, the
polynucleotide may correspond to RNA, and the self-assembly may
occur through RNA canvas assembly (i.e., assemblies comprising RNA
tiles), etc. Example structures that may be formed through
polynucleotide self-assembly are described in Wei et al., "Complex
shapes self-assembled from single-stranded DNA tiles," Nature, Vol.
485, (May 31, 2012), pp. 623-626; Kershner et al. "Placement and
orientation of individual DNA shapes on lithographically patterned
surfaces," Nature Nanotechnology, (Aug. 16, 2009), pp. 1-4; and
Anderson et al., "Self-assembly of a nanoscale DNA box with a
controllable lid," Nature Vol. 459, (May 7, 2009), pp. 73-76.
[0018] The illustrated pattern of FIGS. 2 and 2A is an example
pattern. Self-assembly of polynucleotide may be utilized to create
other desired patterns in other embodiments. The specific pattern
of FIGS. 2 and 2A may be utilized to fabricate a tight spacing of
contacts or other features, and may be utilized, for example, to
fabricate highly-integrated memory, sensors logic, MEMS
(microelectromechanical systems), etc.
[0019] The polynucleotide 18 may be considered to be a
polynucleotide mask formed over semiconductor substrate 12.
Numerous methods may be utilized for transferring a pattern from
the polynucleotide mask to the underlying semiconductor substrate
12. Example methods are described with reference to FIGS. 3-8.
Referring to FIG. 3, a material 22 is selectively formed on an
upper surface of polynucleotide 18 relative to upper surfaces of
substrate 12. The material 22 may comprise any suitable material.
For instance, in some embodiments material 22 may comprise
electrically insulative material (for instance, silicon dioxide),
or electrically conductive material (for instance, metal or
metal-containing compositions). Example methods for adhering
material selectively to polynucleotide relative to other surfaces
are described in, for example, Surwade et al., "Nanoscale growth
and patterning of inorganic oxides using DNA nanostructures
templates," Journal of the American Chemical Society (2013), 135,
pp 6778-6781.
[0020] Referring to FIGS. 4 and 5, the material 22 may be utilized
as a mask for fabricating features associated with semiconductor
substrate 12. FIG. 4 shows an application in which the material 22
is utilized as an etch mask to protect underlying features during
an etch into semiconductor substrate 12. FIG. 5 shows an
application in which the material 22 is utilized as a mask during
implanting of dopant into the exposed regions of a semiconductor
substrate 12 to form doped regions 24. The processing of FIGS. 4
and 5 may also be combined so that etching is conducted into the
exposed regions of semiconductor substrate 12, and dopant is
implanted into the exposed regions. In some embodiments, processing
of FIGS. 4 and 5 may be combined with other masking processes (for
example, photolithography). Thus, region 16 may be protected with a
photolithographically-patterned mask during the etch of FIG. 4 or
the implant of FIG. 5.
[0021] The patterns established by material 22 in FIGS. 4 and 5 are
defined by the polynucleotide mask formed with polynucleotide 18.
Such polynucleotide mask may or may not remain under material 22
during the processing of FIGS. 4 and 5, depending on whether or not
the polynucleotide can survive the processing conditions.
[0022] The processing of FIG. 3 forms a positive mask over
polynucleotide 18 (i.e., the mask has the same shape as the
underlying polynucleotide). In other embodiments, a negative mask
may be formed relative to the polynucleotide 18 (i.e., the mask may
have a complementary shape relative to the underlying
polynucleotide). FIG. 6 shows construction 10 at a processing stage
subsequent to that of FIG. 2 in accordance with an embodiment in
which masking material 22 forms a negative mask relative to
polynucleotide 18. Example methods for forming a negative mask
relative to polynucleotide are described in, for example, Surwade
et al., "Nanoscale growth and patterning of inorganic oxides using
DNA nanostructures templates," Journal of the American Chemical
Society (2013), 135, pp 6778-6781.
[0023] Referring to FIGS. 7 and 8, the polynucleotide 18 (FIG. 6)
is removed and the remaining material 22 is utilized as a mask for
fabricating features associated with semiconductor substrate 12.
FIG. 7 shows an application in which the material 22 is utilized as
an etch mask to protect underlying features during an etch into
semiconductor substrate 12. FIG. 8 shows an application in which
the material 22 is utilized as a mask during implanting of dopant
into the exposed regions of a semiconductor substrate 12 to form
doped regions 26. The processing of FIGS. 7 and 8 may also be
combined so that etching is conducted into the exposed regions of
semiconductor substrate 12, and dopant is implanted into the
exposed regions. In some embodiments, processing of FIGS. 7 and 8
may be combined with other masking processes (for example,
photolithography). The patterns established by material 22 in FIGS.
7 and 8 are defined by the polynucleotide mask formed with
polynucleotide 18, and correspond to an approximate inverse image
of such pattern.
[0024] In some embodiments, polynucleotide 18 is a sacrificial
material utilized for patterning features associated with
semiconductor substrate 12. In other embodiments, polynucleotide 18
may be incorporated into the features associated with semiconductor
substrate 12. In some embodiments polynucleotide 18 may be referred
to as a "polynucleotide mask" incorporated into features associated
with semiconductor substrate 12. In such embodiments, at least some
of the "polynucleotide mask" corresponds to patterned
polynucleotide suitable for incorporation into the desired
features; and may or may not also be used for patterning etches,
implants, etc. as a traditional "mask". FIG. 9 illustrates an
example embodiment in which polynucleotide 18 is incorporated into
an integrated assembly, and specifically is incorporated into
features 28. Such features may comprise, for example, transistors,
wiring, etc. The polynucleotide may be an important component of
the features. For instance, the polynucleotide may provide desired
physical and/or chemical properties to the features. Further, the
polynucleotide may be configured for specific binding of one or
more molecules, and such binding may alter electrical properties of
the features so that the polynucleotide may be incorporated into an
indicator for detecting the presence of such molecules, and
possibly also for determining a concentration of the molecules
(i.e., in sensor applications).
[0025] FIGS. 10 and 11 illustrate an example method for altering
one of the regions 14 and 16 relative to the other. FIG. 10 shows a
mask 30 formed across region 16 relative to region 14. Such mask
may be formed with any suitable processing, including, for example,
photolithographic processing, pitch-multiplication processing, etc.
In some embodiments, mask 30 may comprise photoresist.
[0026] The mask 30 protects region 16 while leaving the region 14
exposed. In some embodiments, the mask 30 over region 16 is enough
to create the difference in physisorption desired so that
polynucleotide specifically adheres to region 14 relative to region
16 (or vice versa). In some embodiments, the physisorption may be
enhanced by providing dopant within region 14. For instance, dopant
may be implanted into the exposed region 14 to form the doped
region 32. The polynucleotide may be specifically adhered to region
14 after formation of the doped region 32. The mask 30 may remain
over region 16 while the polynucleotide is adhered to region 14, or
alternatively the mask 38 may be removed.
[0027] FIG. 11 shows a processing stage subsequent to that of FIG.
10, and shows mask 30 removed. The construction 10 of FIG. 11 may
be subsequently exposed to polynucleotide, and the polynucleotide
may selectively adhere to region 14 relative to region 16 due to
the doped region 32. Alternatively, the polynucleotide may
specifically adhere to region 16 relative to region 14 due to the
doped region 32; depending on the type of dopant utilized, the
surface characteristics of regions 14 and 16, etc.
[0028] The doping of FIG. 10 may be accomplished with any suitable
processing. For instance, dopant may be implanted into substrate 12
with conventional implantation technology, and may be implanted to
form a relatively deep doped region 32. Alternatively, the dopant
may be implanted utilizing shallow ion implantation and/or plasma
doping (PLAD) to form a relatively shallow doped region 32.
[0029] The dopant within doped region 32 may be any suitable dopant
including, for example, p-type dopant, n-type dopant, neutral
dopant, metal, etc. For instance, in some embodiments, the dopant
may comprise one or more of phosphorus, arsenic, boron, magnesium,
potassium, calcium, etc.
[0030] The construction 10 at the processing stage of FIG. 11 has
an altered first region 14 with different physisorption
characteristics for polynucleotide relative to the second region
16. The altered first region may have enhanced affinity for
polynucleotide relative to the second region in some embodiments,
and in other embodiments may have reduced affinity for
polynucleotide relative to the second region. Subsequent processing
analogous to that described above with reference to FIGS. 1-9 may
be conducted to form a polynucleotide mask across one of the
regions 14 and 16 of FIG. 11, and to utilize such mask for
fabrication of features associated with semiconductor substrate
12.
[0031] The exposed surfaces 15 and 17 of regions 14 and 16 at the
processing stage of FIG. 11 may comprise semiconductor material of
substrate 12. Alternately, one or both of such exposed surfaces may
comprise insulative material and/or conductive material formed
across semiconductor material of substrate 12. For instance, FIGS.
12 and 13 show construction 10 at processing stages analogous to
those of FIGS. 10 and 11, respectively, but in which a second
material 34 is formed across semiconductor material of substrate
12. The second material may be conductive, insulative or
semiconductive. The doped region 32 extends into the second
material to alter polynucleotide physisorption characteristics of
the second material within region 14 relative to the second
material within region 16. In the shown embodiment doped region 32
extends only into material 34, but in other embodiments the doped
region may extend through material 34 and into underlying material
of substrate 12.
[0032] The construction 10 at the processing stage of FIG. 13 has
an altered first region 14 with different physisorption
characteristics for polynucleotide relative to the second region
16. The altered first region may have enhanced affinity for
polynucleotide relative to the second region in some embodiments,
and in other embodiments may have reduced affinity for
polynucleotide relative to the second region. Subsequent processing
analogous to that described above with reference to FIGS. 1-9 may
be conducted to form a polynucleotide mask across one of the
regions 14 and 16 of FIG. 13, and to utilize such mask for
fabrication of features associated with semiconductor substrate
12.
[0033] Dopant may be provided selectively into one of regions 14
and 16 relative to the other with any suitable processing. The
processing of FIGS. 9-13 comprises direct implanting of dopant into
a material. Another method is to provide dopant within a
sacrificial layer, and to then transfer dopant from the sacrificial
layer into one of the regions 14 and 16. For instance, FIG. 14
shows construction 10 at a processing stage in which a sacrificial
layer 36 is formed across substrate 12. The sacrificial layer has
dopant 38 provided therein, with such dopant being indicated by
stippling.
[0034] Referring next to FIG. 15, at least some of the dopant is
transferred from the layer 36 into semiconductor substrate 12 to
form the doped region 32 within substrate 12. Such transfer may be
accomplished utilizing thermal anneal conditions, electric field
conditions, electrochemical conditions, or any other suitable
methodology.
[0035] Referring to FIG. 16, layer 36 (FIG. 15) is removed to leave
a construction analogous to that described above with reference to
FIG. 11. In other example embodiments, a second layer analogous to
the layer 34 of FIG. 12 may be formed across substrate 12 prior to
forming sacrificial layer 36, and the construction of FIG. 16 may
be fabricated to be analogous to that of FIG. 13.
[0036] The construction 10 at the processing stage of FIG. 16 has
an altered first region 14 with different physisorption
characteristics for polynucleotide relative to the second region
16. The altered first region may have enhanced affinity for
polynucleotide relative to the second region in some embodiments,
and in other embodiments may have reduced affinity for
polynucleotide relative to the second region. Subsequent processing
analogous to that described above with reference to FIGS. 1-9 may
be conducted to form a polynucleotide mask across one of the
regions 14 and 16 of FIG. 16, and to utilize such mask for
fabrication of features associated with semiconductor substrate
12.
[0037] Another method for altering polynucleotide physisorption
characteristics of region 14 relative to region 16 is described
with reference to FIGS. 17 and 18. Referring to FIG. 17, a material
40 is formed across the semiconductor substrate 12. Material 40 may
have components incorporated therein which alter physisorption
characteristics of the material for polynucleotide. Such components
may include chemical species (for instance, organometallic
substances, hydrogen, organo-alkaline earth compounds, magnesium
ion, calcium ion, etc.); and/or may include trapped charges (e.g.,
unsaturated bonds, dangling bonds, unbound electrons, etc.).
Material 40 may be insulative, conductive, semiconductive, etc.
[0038] The material 40 may be deposited with any suitable
methodology including, for example, chemical vapor deposition
(CVD), atomic layer deposition (ALD), plasma-enhanced chemical
vapor deposition (PECVD), etc. In some embodiments, charging or
polarizing components may be introduced in a gas flow during a
deposition process (for instance, CVD, ALD and/or reactive
sputtering) to incorporate desired components within the material
40. For instance, additional hydrogen may be introduced into the
gas flow. Additionally, or alternatively, one or both of various
organometallic materials and/or various organo-alkaline earth
compounds may be introduced into the gas flow. Example materials
are calcium bis (2,2,6,6-tetramethyl-3,5-heptanedionate), calcium
2-ethylhexanoate, calcium methoxide, bis
(2,2,6,6-tetramethyl-3,5-heptanedionato) magnesium II dihydrate,
etc.
[0039] In some embodiments, material 40 may comprise a composition
deposited under conditions which incorporate trapped charges within
at least a portion of the thickness of material 40. Such
composition may comprise, for example, silicon dioxide, silicon
nitride, carbon, etc.
[0040] A masking material 42 is formed and patterned over material
40. The masking material may comprise any suitable material, and in
some embodiments may comprise photoresist patterned utilizing
photolithography and/or may comprise material patterned utilizing
pitch-multiplication methodologies.
[0041] Referring to FIG. 18, material 40 is patterned utilizing
masking material 42 (FIG. 17) and an appropriate etch, and
subsequently masking material 42 is removed. The construction 10 of
FIG. 18 comprises a region 14 with an upper surface corresponding
to the upper surface of material 40, and a region 16 with an upper
surface corresponding to the upper surface of substrate 12. The
upper surface of region 14 may have different physisorption
characteristics for polynucleotide relative to the upper surface of
region 16. Depending on the nature of material 40 and substrate 12,
region 14 may have enhanced physisorption of polynucleotide as
compared to region 16 or may have reduced physisorption of
polynucleotide as compared to region 16.
[0042] The construction 10 at the processing stage of FIG. 18 has
an altered first region 14 with different physisorption
characteristics for polynucleotide relative to the second region
16. The altered first region may have enhanced affinity for
polynucleotide relative to the second region in some embodiments,
and in other embodiments may have reduced affinity for
polynucleotide relative to the second region. Subsequent processing
analogous to that described above with reference to FIGS. 1-9 may
be conducted to form a polynucleotide mask across one of the
regions 14 and 16 of FIG. 18, and to utilize such mask for
fabrication of features associated with semiconductor substrate
12.
[0043] Another method for altering polynucleotide physisorption
characteristics of region 14 relative to region 16 is described
with reference to FIGS. 19-21. Referring to FIG. 19, a conductive
material 44 is formed and patterned across the semiconductor
substrate 12. Material 44 may comprise any suitable composition or
combination of compositions; and in some embodiments may comprise,
consist essentially of, or consist of one or more of various metals
(for example, tungsten, titanium, etc.), metal-containing
compositions (for instance, metal nitride, metal carbide, metal
silicide, etc.), and conductively-doped semiconductor materials
(for instance, conductively-doped silicon, conductively-doped
germanium, etc.). The material 44 may be patterned with any
suitable processing, including, for example, utilization of a
patterned mask (not shown) and suitable etching; and/or direct
deposition of material 44 into the desired pattern. The material 44
may be patterned in any suitable configuration, including, for
example, wiring, a memory cell array, etc.
[0044] Referring to FIGS. 20 and 21, the construction of FIG. 19 is
illustrated after it has been exposed to polynucleotide which
selectively adheres to region 14 relative to region 16 (FIG. 20),
or to region 16 relative to region 14 (FIG. 21). In the shown
embodiments, the polynucleotide self-assembles to form a pattern
with openings 20 extending therethrough, analogous to the pattern
described above with reference to FIG. 2. In subsequent processing,
a pattern from the polynucleotide may be transferred into or
through materials underlying the polynucleotide analogous to the
processing described above with reference to FIGS. 4 and 7, and/or
the pattern from the polynucleotide may be utilized for patterning
a dopant implant in processing analogous to that described above
with reference to FIGS. 5 and 8. For instance, in processing
subsequent to that of FIG. 20, the pattern from the mask of
polynucleotide 18 may be transferred into or through conductive
material 44 to fabricate such conductive material into one or more
conductive components. Additionally, or alternatively, the
polynucleotide 18 may be incorporated into an integrated assembly
analogous to the assembly described above with reference to FIG.
9.
[0045] Although wiring 44 is shown formed over the surface of
substrate 12, in other embodiments the wiring may be in trenches
that extend into substrate 12 (for instance, the wiring may be
formed with damascene processing) and/or the wiring may correspond
to doped regions along the upper surface of substrate 12. In some
embodiments in which the wiring corresponds to doped regions,
processing analogous to that of FIGS. 20 and 21 may follow the
processing stage of FIG. 11, FIG. 13 or FIG. 16.
[0046] In some embodiments, the processing of FIGS. 19-21 may
utilize an alteration of the surface potential characteristics of
region 14 relative to region 16, which in turn alters
polynucleotide physisorption characteristics of region 14 relative
to region 16. Specifically, electrical bias may be applied to the
conductive material 44 to attract the polynucleotide and thereby
enhance physisorption of the polynucleotide along the upper surface
of the conductive material, or to repel the polynucleotide and
thereby reduce physisorption of the polynucleotide along the upper
surface of the conductive material. Electrical bias may be utilized
similarly in embodiments of the types described above with
reference to FIGS. 11, 13 and 16. Specifically, a doped region may
be provided with sufficient dopant to become electrically
conductive, and electrical bias may be provided to such
electrically conductive region to either attract polynucleotide or
repel polynucleotide. In some embodiments, electrical bias may be
applied to both of regions 14 and 16 to alter surface potential of
one of the regions relative to the other.
[0047] Another method for altering polynucleotide physisorption
characteristics of region 14 relative to region 16 is described
with reference to FIGS. 22 and 23. FIG. 22 shows construction 10 at
a processing stage in which there is no difference between the
upper surfaces of regions 14 and 16. FIG. 23 shows the construction
after region 14 is exposed to a corona discharge which creates an
altered upper portion 46 of region 14 and changes polynucleotide
physisorption characteristics of region 14. Accordingly, the
construction 10 at the processing stage of FIG. 23 has an altered
first region 14 with different physisorption characteristics for
polynucleotide relative to the second region 16. The altered first
region may have enhanced affinity for polynucleotide relative to
the second region in some embodiments, and in other embodiments may
have reduced affinity for polynucleotide relative to the second
region. Subsequent processing analogous to that described above
with reference to FIGS. 1-9 may be conducted to form a
polynucleotide mask across one of the regions 14 and 16 of FIG. 23,
and to utilize such mask for fabrication of features associated
with semiconductor substrate 12.
[0048] In some embodiments, the corona discharge may be considered
an example of a method utilized to alter surface potential
characteristics of the first region 14 relative to the second
region 16.
[0049] Another method for altering polynucleotide physisorption
characteristics of region 14 relative to region 16 is described
with reference to FIGS. 24 and 25. Referring to FIG. 24, regions 14
and 16 have upper surfaces 15 and 17 which differ relative to one
another. The difference between upper surfaces 15 and 17 may be,
for example, a difference in physical characteristics, chemical
characteristics, electrically characteristics, etc. In the shown
embodiment, the upper surfaces 15 and 17 are along materials 45 and
47 which differ from one another. The construction of FIG. 24 is an
example construction having upper surfaces of regions 14 and 16
differing relative to one another, and may be replaced with other
suitable configurations in other embodiments. For instance, the
construction of FIG. 24 may be replaced with any of the
constructions of FIGS. 11, 13, 16, 18, 19 and 23 in other
embodiments.
[0050] Referring to FIG. 25, construction 10 is exposed to material
50 which alters polynucleotide physisorption characteristics of the
upper surface of region 14 relative to the upper surface of region
16. Material 50 has an oriented molecular arrangement relative to
the upper surface of region 14, and does not adhere with the upper
surface of region 16. The material 50 may comprise a brush layer, a
self-assembling pattern (for instance, a self-assembling
monolayer), etc. The individual molecules of material 50 may
comprise head groups oriented toward the upper surface of region
14, and tail groups which extend outwardly from substrate 12. The
tail groups may be considered to be terminal groups, and in the
embodiment of FIG. 25 are indicated with boxes 51 (only some of
which are labeled). Such terminal groups may be configured to
either repel polynucleotide or attract polynucleotide. For
instance, in some embodiments the terminal groups may be negatively
charged, partially negatively charged, positively charged or
partially positively charged. In some embodiments the terminal
groups may comprise charged carboxylate groups or charged amino
groups. In some embodiments, material 50 comprises
poly(dimethylamino)ethyl methacrylate. In some embodiments,
material 50 comprises one or more coordinated transition metals. In
some embodiments, material 50 comprises a di-positive nickel
macrocycle, such as, for example, dinickel (II) (2,2'-bis
(1,3,5,8,12-pentaazacyclotetradec-3-yl)-diethyl disulfide)
perchlorate.
[0051] The construction 10 at the processing stage of FIG. 25 has
an altered first region 14 with different physisorption
characteristics for polynucleotide relative to the second region
16. The altered first region may have enhanced affinity for
polynucleotide relative to the second region in some embodiments,
and in other embodiments may have reduced affinity for
polynucleotide relative to the second region. Subsequent processing
analogous to that described above with reference to FIGS. 1-9 may
be conducted to form a polynucleotide mask across one of the
regions 14 and 16 of FIG. 25, and to utilize such mask for
fabrication of features associated with semiconductor substrate
12.
[0052] Another method for altering polynucleotide physisorption
characteristics of region 14 relative to region 16 is described
with reference to FIGS. 26 and 27. Referring to FIG. 26, a
conductive material 60 extends across the regions 14 and 16 of
semiconductor substrate 12. A masking material 62 covers the
portion of conductive material 60 across region 16, while leaving
the portion across region 14 exposed. In some embodiments,
conductive material 60 may comprise wiring which extends across a
memory array region and a peripheral region adjacent such memory
array region. In such embodiments, the masking material 62 may
protect the portion of the wiring across the peripheral region
while leaving a remaining portion of the wiring exposed for further
patterning, or vice versa.
[0053] Referring to FIG. 27, construction 10 is illustrated after
physisorption of polynucleotide 18 onto the exposed portion of
conductive material 60, and after self-assembly of the
polynucleotide to form a pattern.
[0054] The physisorption of polynucleotide 18 onto conductive
material 60 may comprise application of an electrical bias to the
conductive material to attract the polynucleotide onto an upper
surface of the conductive material. Although the illustrated
conductive material is wiring provided over semiconductor substrate
12, in other embodiments other conductive configurations may be
utilized. For instance, the conductive material may correspond to
dopant provided within substrate 12, to wiring provided within
trenches in the substrate through damascene processing, etc. In
some applications, wiring 60 may be replaced with a molecular
arrangement 50 of the type shown in FIG. 25, and mask 62 may be
utilized to cover part of the molecular arrangement while leaving
the remainder of the molecular arrangement exposed for
physisorption of polynucleotide.
[0055] The polynucleotide 18 of FIG. 27 may be considered to form a
patterned mask over region 14. In subsequent processing, such
patterned mask may be utilized in processing analogous to that
described above with reference to FIGS. 3-8 for fabricating
features associated with substrate 12.
[0056] The physisorption of the embodiments of FIGS. 1-27 may be
utilized in combination with other processes. For instance, in some
embodiments physisorption may be combined with chemical bonding
(i.e., chemisorption) to lock a polynucleotide into a desired
configuration. Example chemisorption may comprise chemical bonding
of polynucleotide to a substrate (for instance, thermal or
ultraviolet assisted cross-linking of the polynucleotide to the
substrate). In some embodiments, physisorption may be used to
loosely orient polynucleotide to a surface, and then chemisorption
may be used to lock the polynucleotide into a desired
alignment.
[0057] The physisorption processes described herein may offer
advantages relative to conventional methods. For instance, some
conventional methods may not be suitable for semiconductor
fabrication in that they may introduce undesired contaminants into
a fabrication process. In contrast, methodology described herein
may enable physisorption of polynucleotide to underlying materials
through controlled ionic interactions (i.e., utilization of dopant,
terminal groups of oriented molecules, electrostatic double layers
in ionic solution, etc.), and/or through utilization of electrical
bias. Accordingly, some embodiments provided herein advantageously
enable polynucleotide physisorption onto semiconductor substrates
while omitting problematic salts and other materials associated
with conventional methods of polynucleotide physisorption.
[0058] Unless specified otherwise, the various materials,
substances, compositions, etc. described herein may be formed with
any suitable methodologies, either now known or yet to be
developed, including, for example, atomic layer deposition (ALD),
chemical vapor deposition (CVD), physical vapor deposition (PVD),
etc.
[0059] Both of the terms "dielectric" and "insulative" may be
utilized to describe materials having insulative electrical
properties. The terms are considered synonymous in this disclosure.
The utilization of the term "dielectric" in some instances, and the
term "insulative" in other instances, may be to provide language
variation within this disclosure to simplify antecedent basis
within the claims that follow, and is not utilized to indicate any
significant chemical or electrical differences.
[0060] 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.
[0061] 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.
[0062] 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.
[0063] Some embodiments include a method of fabricating features
associated with a semiconductor substrate. Surface potential
characteristics of a first region of the semiconductor substrate
are altered relative to a second region. The altered first region
has different physisorption characteristics for polynucleotide
relative to the second region. The altered first region and the
second region are exposed to polynucleotide. The polynucleotide
selectively adheres to either the altered first region or the
second region to form a polynucleotide mask. The polynucleotide
mask is used during fabrication of features associated with the
semiconductor substrate.
[0064] Some embodiments include a method of fabricating features
associated with a semiconductor substrate. Dopant is provided into
a first region of the semiconductor substrate to alter the first
region relative to a second region. The altered first region has
different physisorption characteristics for polynucleotide relative
to the second region. The altered first region and the second
region are exposed to polynucleotide. The polynucleotide
selectively adheres to either the altered first region or the
second region to form a polynucleotide mask. The polynucleotide
mask is used during fabrication of features associated with the
semiconductor substrate.
[0065] Some embodiments include a method of fabricating features
associated with a semiconductor substrate. A material is deposited
across a first region of the semiconductor substrate to alter the
first region relative to a second region. The altered first region
has different physisorption characteristics for polynucleotide
relative to the second region. The deposition incorporates
components within the material that alter the physisorption
characteristics of the material for the polynucleotide. The altered
first region and the second region are exposed to polynucleotide.
The polynucleotide selectively adheres to either the altered first
region or the second region to form a polynucleotide mask. The
polynucleotide mask is used during fabrication of features
associated with the semiconductor substrate.
[0066] Some embodiments include a method of fabricating features
associated with a semiconductor substrate. A material is formed
across a first region of the semiconductor substrate to alter the
first region relative to a second region. The altered first region
has different physisorption characteristics for polynucleotide
relative to the second region. The forming of the material
comprises orienting a molecular arrangement relative to a surface
of the semiconductor substrate. The altered first region and the
second region are exposed to polynucleotide. The polynucleotide
selectively adheres to either the altered first region or the
second region to form a polynucleotide mask. The polynucleotide
mask is used during fabrication of features associated with the
semiconductor substrate.
[0067] 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.
* * * * *