U.S. patent application number 12/835018 was filed with the patent office on 2010-11-04 for method of concurrently patterning a substrate having a plurality of fields and a plurality of alignment marks.
This patent application is currently assigned to MOLECULAR IMPRINTS, INC.. Invention is credited to Byung-Jin Choi, Ian M. McMackin, Christopher Mark Melliar-Smith, Sidlgata V. Sreenivasan.
Application Number | 20100278954 12/835018 |
Document ID | / |
Family ID | 38581610 |
Filed Date | 2010-11-04 |
United States Patent
Application |
20100278954 |
Kind Code |
A1 |
Sreenivasan; Sidlgata V. ;
et al. |
November 4, 2010 |
Method of Concurrently Patterning a Substrate Having a Plurality of
Fields and a Plurality of Alignment Marks
Abstract
Imprint lithography templates for patterning substrates are
described. The templates include a section having a mold a first
pattern of alignment forming areas and template alignment marks.
The additional sections are generally devoid of a mold. One or more
of the additional section may include the first pattern of a second
pattern of alignment forming areas and template alignment marks.
The second pattern may correspond to the first pattern.
Inventors: |
Sreenivasan; Sidlgata V.;
(Austin, TX) ; McMackin; Ian M.; (Austin, TX)
; Melliar-Smith; Christopher Mark; (Austin, TX) ;
Choi; Byung-Jin; (Austin, TX) |
Correspondence
Address: |
MOLECULAR IMPRINTS
PO BOX 81536
AUSTIN
TX
78708-1536
US
|
Assignee: |
MOLECULAR IMPRINTS, INC.
Austin
TX
|
Family ID: |
38581610 |
Appl. No.: |
12/835018 |
Filed: |
July 13, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11695850 |
Apr 3, 2007 |
7780893 |
|
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12835018 |
|
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60788806 |
Apr 3, 2006 |
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Current U.S.
Class: |
425/385 ;
977/902 |
Current CPC
Class: |
B29C 43/021 20130101;
B29C 43/003 20130101; G03F 9/7084 20130101; B82Y 40/00 20130101;
Y10S 977/887 20130101; B29C 2043/025 20130101; G03F 7/0002
20130101; G03F 9/703 20130101; B82Y 10/00 20130101; G03F 9/708
20130101; G03F 9/7042 20130101; B29C 2043/5825 20130101; G03F
9/7076 20130101; B29C 43/58 20130101; B29C 2043/142 20130101 |
Class at
Publication: |
425/385 ;
977/902 |
International
Class: |
B28B 11/08 20060101
B28B011/08 |
Claims
1. A nano imprint lithography template, comprising: a plurality of
sections including: a first section having a mold and a first
subset of alignment forming areas and a plurality of template
alignment marks defining a first pattern; and a second section
having a second subset of alignment forming areas and a plurality
of template alignment marks defining a second pattern; wherein the
first pattern corresponds to the second pattern.
2. The nano imprint lithography template of claim 1, wherein the
second section is devoid of a mold.
3. The nano imprint lithography template of claim 1, wherein the
alignment forming areas are checkerboard forming alignment marks
and the template alignment marks are grating alignment marks.
4. The template of claim 1, wherein the alignment forming areas are
checkerboard forming alignment marks and the template alignment
marks are substantially planar.
5. A nano imprint lithography template, comprising: a first section
having a first dimension of a length and a width, the first section
having a mold with a relief pattern; and, a second section having
second dimensions of a length and a width, the second section
devoid of a mold, wherein the first dimensions are substantially
similar to the second dimensions.
6. The nano imprint lithography template of claim 5, further
comprising a first pattern of alignment forming areas and template
alignment marks positioned adjacent to the first section.
7. The nano imprint lithography template of claim 6, further
comprising a second pattern of alignment forming areas and template
alignment marks positioned adjacent to the second section, wherein
the first pattern is different from the second pattern.
8. A nano imprint lithography template, comprising: a plurality of
sections, each section having substantially similar dimensions of
length and width, with only one of the plurality of sections having
a mold, the mold having a relief pattern defined therein.
9. The template of claim 8, further comprising a plurality of
alignment forming areas and template alignment marks.
10. The template of claim 9, wherein each section is separated from
each adjacent section by a street and each section is separated
from the perimeter of the template by a street and the plurality of
alignment forming areas and template alignment marks are positioned
within the streets.
11. The template of claim 10, wherein the alignment forming areas
are checkerboard forming alignment marks and the template alignment
marks are grating alignment marks.
12. The template of claim 10, wherein the alignment forming areas
are checkerboard forming alignment marks and the template alignment
marks are substantially planar.
13. The template of claim 8, further comprising a first subset of
alignment forming areas and a first subset of template alignment
marks defining a first pattern positioned adjacent to the mold.
14. The template of claim 13, further comprising a second subset of
alignment forming areas and a second subset of template alignment
marks defining a second pattern, wherein the second pattern
corresponds to the first pattern.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a continuation of U.S. patent
application Ser. No. 11/695,850 filed Apr. 3, 2007, which claims
priority to U.S. provisional application No. 60/788,806 filed on
Apr. 3, 2006, both of which are incorporated herein by
reference.
BACKGROUND INFORMATION
[0002] Nano-fabrication involves the fabrication of very small
structures, e.g., having features on the order of nanometers or
smaller. One area in which nano-fabrication has had a sizeable
impact is in the processing of integrated circuits. As the
semiconductor processing industry continues to strive for larger
production yields while increasing the circuits per unit area
formed on a substrate, nano-fabrication becomes increasingly
important. Nano-fabrication provides greater process control while
allowing increased reduction of the minimum feature dimension of
the structures formed. Other areas of development in which
nano-fabrication has been employed include biotechnology, optical
technology, mechanical systems and the like.
[0003] An exemplary nano-fabrication technique is commonly referred
to as imprint lithography. Exemplary imprint lithography processes
are described in detail in numerous publications, such as U.S.
patent application publication no. 2004/0065976 filed as U.S.
patent application Ser. No. 10/264,960; U.S. patent application
publication no. 2004/0065252 filed as U.S. patent application Ser.
No. 10/264,926; and U.S. Pat. No. 6,936,194, entitled "Functional
Patterning Material for Imprint Lithography Processes," all of
which are assigned to the assignee of the present invention.
[0004] The imprint lithography technique disclosed in each of the
aforementioned U.S. patent application publications and U.S. patent
includes formation of a relief pattern in a polymerizable layer and
transferring a pattern corresponding to the relief pattern into an
underlying substrate. The substrate may be positioned upon a stage
to obtain a desired position to facilitate patterning thereof. To
that end, a mold is employed spaced-apart from the substrate with a
formable liquid present between the mold and the substrate. The
liquid is solidified to form a patterned layer that has a pattern
recorded therein that is conforming to a shape of the surface of
the mold in contact with the liquid. The mold is then separated
from the patterned layer such that the mold and the substrate are
spaced-apart. The substrate and the patterned layer are then
subjected to processes to transfer, into the substrate, a relief
image that corresponds to the pattern in the patterned layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a simplified side view of a lithographic system
having a template spaced-apart from a substrate;
[0006] FIG. 2 is a simplified side view of the substrate shown in
FIG. 1, having a patterned layer positioned thereon;
[0007] FIG. 3 is a top down view of the template shown in FIG.
1;
[0008] FIG. 4 is a flow chart of a method of forming the template
shown in FIG. 1;
[0009] FIG. 5 is a top down view of a master template formed from
e-beam lithography, the master template employed to form template
shown in FIG. 1;
[0010] FIG. 6 is a top down view of an intermediate substrate
formed from the master template shown in FIG. 1; the intermediate
substrate having a first field formed and a plurality of substrate
alignment marks;
[0011] FIG. 7 is a top down view of the substrate alignment marks
shown in FIG. 6;
[0012] FIG. 8 is a top down view of the master template, shown in
FIG. 1, in superimposition with a portion of the intermediate
substrate, shown in FIG. 6, with a mesa of the master template
being in superimposition with a second field of the intermediate
substrate;
[0013] FIG. 9 is a top down view of the master template, shown in
FIG. 1, in superimposition with a portion of the intermediate
substrate, shown in FIG. 6, with a mesa of the master template
being in superimposition with a third field of the intermediate
substrate;
[0014] FIG. 10 is a top down view of the master template, shown in
FIG. 1, in superimposition with a portion of the intermediate
substrate, shown in FIG. 6, with a mesa of the master template
being in superimposition with a fourth field of the intermediate
substrate;
[0015] FIG. 11 is a top down view of the intermediate substrate,
shown in FIG. 6, with a plurality of alignment marks being formed
thereon prior to patterning the intermediate substrate; and
[0016] FIG. 12 is a top down view of the master template, the
master template having 9 fields associated therewith.
DETAILED DESCRIPTION
[0017] Referring to FIG. 1, a system 10 to form a relief pattern on
a substrate 12 is shown. Substrate 12 may be coupled to a substrate
chuck 14. Substrate chuck 14 may be any chuck including, but not
limited to, vacuum, pin-type, groove-type, or electromagnetic, as
described in U.S. Pat. No. 6,873,087 entitled "High-Precision
Orientation Alignment and Gap Control Stages for Imprint
Lithography Processes," which is incorporated herein by reference.
In a further embodiment, substrate chuck 14 may be a chuck as
described in U.S. Pat. No. 6,982,783 entitled "Chucking System for
Modulating Shapes of Substrates" and U.S. Pat. No. 6,980,282
entitled "Method for Modulating Shapes of Substrates", both of
which are incorporated herein by reference. Substrate 12 and
substrate chuck 14 may be supported upon a stage 16. Further, stage
16, substrate 12, and substrate chuck 14 may be positioned on a
base (not shown). Stage 16 may provide motion along the x and y
axes.
[0018] Spaced-apart from substrate 12 is a template 18 having a
mold 20 extending therefrom towards substrate 20 with a patterning
surface 22 thereon. Further, mesa 20 may be referred to as a mold
20. Mesa 20 may also be referred to as a nanoimprint mold 20. In a
further embodiment, template 18 may be substantially absent of mold
20. Template 18 and/or mold 20 may be formed from such materials
including but not limited to, fused-silica, quartz, silicon,
organic polymers, siloxane polymers, borosilicate glass,
fluorocarbon polymers, metal, and hardened sapphire. As shown,
patterning surface 22 comprises features defined by a plurality of
spaced-apart recesses 24 and protrusions 26. However, in a further
embodiment, patterning surface 22 may be substantially smooth
and/or planar. Patterning surface 20 may define an original pattern
that forms the basis of a pattern to be formed on substrate 12.
[0019] Template 18 may be coupled to a template chuck 28, template
chuck 28 being any chuck including, but not limited to, vacuum,
pin-type, groove-type, or electromagnetic, as described in U.S.
Pat. No. 6,873,087. In a further embodiment, substrate chuck 14 may
be a chuck as described in U.S. Pat. No. 6,982,783 and U.S. Pat.
No. 6,980,282. Template chuck 28 may be coupled to an imprint head
30 to facilitate movement of template 18 and mold 20.
[0020] System 10 further comprises a fluid dispense system 32.
Fluid dispense system 32 may be in fluid communication with
substrate 12 so as to deposit a polymeric material 34 thereon.
System 10 may comprise any number of fluid dispensers and fluid
dispense system 32 may comprise a plurality of dispensing units
therein. Polymeric material 34 may be positioned upon substrate 12
using any known technique, e.g., drop dispense, spin-coating, dip
coating, chemical vapor deposition (CVD), physical vapor deposition
(PVD), thin film deposition, thick film deposition, and the like.
As shown, polymeric material 34 may be deposited upon substrate 12
as a plurality of spaced-apart droplets 36. Typically, polymeric
material 34 is disposed upon substrate 12 before the desired volume
is defined between mold 20 and substrate 12. However, polymeric
material 34 may fill the volume after the desired volume has been
obtained.
[0021] Referring to FIGS. 1 and 2, system 10 further comprises a
source 38 of energy 40 coupled to direct energy 40 along a path 42.
Imprint head 30 and stage 16 are configured to arrange mold 20 and
substrate 12, respectively, to be in superimposition and disposed
in path 42. Either imprint head 30, stage 16, or both vary a
distance between mold 20 and substrate 12 to define a desired
volume therebetween such that mold 20 contacts polymeric material
34 and the desired volume is filled by polymeric material 34. More
specifically, polymeric material 34 of droplets 36 may ingress and
fill recesses 24 of mold 20. After the desired volume is filled
with polymeric material 34, source 38 produces energy 40, e.g.,
broadband ultraviolet radiation that causes polymeric material 34
to solidify and/or cross-link conforming to the shape of a surface
44 of substrate 12 and patterning surface 22, defining a patterned
layer 46 on substrate 12. Patterned layer 46 may comprise a
residual layer 48 and a plurality of features shown as protrusions
50 and recessions 52.
[0022] System 10 may further comprise an actuation system 58
surrounding template 18/mold 20 to facilitate alignment and overlay
registration between mold 20 and substrate 12. Actuation system 58
facilitates alignment and overlay registration by selectively
deforming template 18/mold 20. This facilitates correcting various
parameters of the pattern shape, i.e., magnification
characteristics, skew/orthogonality characteristics, and
trapezoidal characteristics. An example of an actuation system 58
is described in U.S. Pat. No. 7,150,622 entitled "Systems for
Magnification and Distortion Correction for Imprint Lithography
Processes"; U.S. Pat. No. 7,170,589 entitled "Apparatus to Vary
Dimensions of a Substrate During Nano-Scale Manufacturing"; and
U.S. Pat. No. 6,916,585 entitled "Method of Varying Template
Dimensions to Achieve Alignment During Imprint Lithography"; all of
which are incorporated by reference herein.
[0023] System 10 may be regulated by a processor 54 that is in data
communication with stage 16, imprint head 30, fluid dispense system
32, source 38, and actuation system 58 operating on a computer
readable program stored in memory 56.
[0024] Referring to FIG. 3, a top down view of template 18 is
shown. More specifically, mold 20 of template 18 is shown
comprising a plurality of dies 60, shown as dies 60a-60d. However,
in a further embodiment, mold 20 may comprise any number of dies,
i.e., 2, 4, 6, 8, or 9 dies. Furthermore, each of dies 60a-60d may
have substantially the same relief structure 61 formed therein. To
that end, formation of dies 60 of mold 20 may be formed employing
e-beam lithography. However, employing e-beam lithography may
result in, inter alia, increased formation time of template 18,
which may be undesirable. To that end, a method of minimizing
formation time of dies 60 of mold 20 is described below.
[0025] Referring to FIGS. 3-5, in a first embodiment, a method of
forming dies 60 of mold 20 is shown. More specifically at step 100,
a master template 62 may be formed employing e-beam lithography.
Master template 62 comprises a plurality of sections 64, shown as
sections 64a-64d. However, in a further embodiment, master template
62 may comprise any number of sections 64, i.e., 2, 4, 6, 8, or 9
sections. Each section of sections 64 may be separated from an
adjacent section of sections 64 by a street 66. Further, each of
sections 64 may be separated from a perimeter 68 of master template
62 by a street 70.
[0026] A section of sections 64 may comprises a mesa 72 having a
relief pattern 74 defined therein. As shown, mesa 72 may be
positioned in section 64a, however, in a further embodiment, mesa
72 may be positioned in any section of sections 64. Mesa 72
comprises sides 76a, 76b, 76c, and 76d, with side 76a being
positioned opposite to side 76c and side 76b being positioned
opposite to side 76d. In an example, master template 62 may have a
thickness of equal to or greater than 4 mm.
[0027] Master template 62 may further comprise a plurality of
alignment forming areas 78 and template alignment marks 80.
Alignment forming areas 78 and template alignment marks 80 may be
positioned within streets 66 and 70. In a further embodiment,
alignment forming areas 78 and template alignment marks 80 may be
positioned on a plurality of mesas. In still a further embodiment,
alignment forming areas 78 may comprise checkerboard forming
alignment marks and template alignment marks 80 may comprise
grating alignment marks. In still a further embodiment, template
alignment marks 80 may be substantially planar.
[0028] Positioned adjacent mesa 72 are a first subset of alignment
forming areas 78 and template alignment marks 80 defining a first
pattern 82a. As shown, positioned proximate each of sides 76a, 76b,
76c, and 76d are two alignment forming areas 78 and two template
alignment marks 80. However, in a further embodiment, any number of
alignment forming areas 78 and template alignment marks 80 may be
positioned proximate sides 76a, 76b, 76c, and 76d.
[0029] Master template 62 may further comprise alignment forming
areas 78 and template alignment marks 80 positioned in streets 66
and 70 proximate to the remaining sections 64 of master template
62. More specifically, a second, third, and fourth subsets of
alignment forming areas 78 and template alignment marks 80 may be
positioned in streets 66 and 70 proximate to sections 64b, 64c, and
64d, respectively, defining a second pattern 82b, a third pattern
82c, and a fourth pattern 82d, respectively. The first pattern 82a
may be substantially the same as the third pattern 82c and the
second pattern 82b may be substantially the same as the fourth
pattern 82d. Further, the first and third patterns 82a and 82c may
be differ from the second and fourth patterns 82b and 82d.
[0030] Referring to FIGS. 4-6, at step 102, polymeric material 34
may be positioned on a intermediate substrate 84 by drop dispense,
spin-coating, dip coating, chemical vapor deposition (CVD),
physical vapor deposition (PVD), thin film deposition, thick film
deposition, and the like. More specifically, intermediate substrate
84 may comprise a plurality of fields 86, shown as fields 86a-86d.
However, in a further embodiment, intermediate substrate 84 may
comprises any number of fields 86, i.e. 2, 4, 6, 8, or 9 fields. In
the present example, the number of fields 86 of intermediate
substrate 84 may be substantially the same as the number of
sections 64 of mater template 62. To that end, polymeric material
34 may be positioned on field 586a. Furthermore, polymeric material
34 may be positioned on a plurality of regions 88, with regions
laying 88 outside of fields 86a-86d. In an example, intermediate
substrate 84 may have a thickness of in a range of 0.05 mm to 3
mm.
[0031] At step 104, a desired spatial relationship may be obtained
between master template 62 and intermediate substrate 84, and more
specifically, between field 86a and mesa 72. Further at step 104,
polymeric material 34 of field 86a may fill the desired volume
between field 86a of intermediate substrate 84 and mesa 72 of
master template 62 and polymeric material 34 of regions 88 may fill
the desired volume between regions 88 of substrate and alignment
forming areas 78 of master template 62.
[0032] At step 106, polymeric material 34 positioned on field 86a
and regions 88 of intermediate substrate 84 may be solidified
and/or cross-linked and mesa 72 of master template 62 may be
separated from polymeric material 34 positioned on field 86a,
defining a patterned layer 90a, and may be separated from polymeric
material 34 positioned on regions 88, defining substrate alignment
marks 92. As a result of intermediate substrate 84 having a
thickness substantially less than a thickness of master template
62, a separation force may be minimized, which may be
desirable.
[0033] Referring to FIG. 7, in a further embodiment, each of
substrate alignment marks 92 may further comprise image placement
metrology marks 94. Image placement metrology marks 94 may be
measured known image placement or image registration systems, e.g.,
LMS IPRO available from Leica Microsystems of Bannockburn, Ill.
[0034] Referring to FIGS. 4, 5, and 8, at step 108, polymeric
material 34 may be positioned on field 86b in any of the methods
mentioned above with respect to FIG. 6 and step 102.
[0035] At step 110, a desired spatial relationship may be obtained
between template alignment marks 80 of master template 62 and
substrate alignment marks 92 of intermediate substrate 84 such that
a desired spatial relationship between master template 62 and
intermediate substrate 84 may be obtained, and more specifically,
in the present example, between field 86b and mesa 72. A desired
spatial relationship between template alignment marks 80 and
substrate alignment marks 92 may include template alignment marks
80 and substrate alignment marks 92 being in superimposition;
however, in a further embodiment, template alignment marks 80 and
substrate alignment marks 92 may be offset in the x-y plane a
desired amount to compensate for variations among the first,
second, third, and fourth patterns 82a, 82b, 82c, and 82d of
alignment forming areas 78 and template alignment marks 80.
[0036] Alignment between template alignment marks 80 and substrate
alignment marks 92 may be determined employing an alignment system
as described in U.S. Pat. No. 7,292,326 entitled "Interferometric
Analysis for the Manufacture of Nano-Scale Devices," which is
incorporated herein by reference. Further at step 110, polymeric
material 34 of field 86b may fill the desired volume between field
86b of intermediate substrate 84 and mesa 72 of master template
62.
[0037] At step 112, polymeric material 34 positioned on field 86b
of intermediate substrate 84 may be solidified and/or cross-linked
and mesa 72 of master template 62 may be separated from polymeric
material 34 positioned on intermediate substrate 84, defining a
patterned layer 90b on field 86b.
[0038] Referring to FIGS. 4, 5, and 9, at step 114, polymeric
material 34 may be positioned on field 86c in any of the methods
mentioned above with respect to FIG. 6 and step 102.
[0039] At step 116, a desired spatial relationship may be obtained
between template alignment marks 80 of master template 62 and
substrate alignment marks 92 of intermediate substrate 84 such that
a desired spatial relationship between master template 62 and
intermediate substrate 84 may be obtained, and more specifically,
in the present example, between field 86c and mesa 72. To that end,
to obtain a desired spatial relationship between template alignment
marks 80 of master template 62 and substrate alignment marks 92,
master template 62 may be rotated about the z-axis, and more
specifically, rotated 180.degree. with respect to intermediate
substrate 84. As a result, a desired spatial relationship may be
obtained between template alignment marks 80 and substrate
alignment marks 92. Further at step 116, polymeric material 34 of
field 86c may fill the desired volume between field 86c of
intermediate substrate 84 and mesa 72 of master template 62. In a
further embodiment, master template 62 may be rotated prior to
positioning polymeric material 34 on fields 86c of intermediate
substrate 84.
[0040] At step 118, polymeric material 34 positioned on field 86c
of intermediate substrate 84 may be solidified and/or cross-linked
and mesa 72 of master template 62 may be separated from polymeric
material 34 positioned on field 86a, defining a patterned layer
90c.
[0041] Referring to FIGS. 4 and 5, at step 120, steps 108, 110, and
112 may be repeated for field 86d of intermediate substrate 84,
defining patterned layer 90d on field 86d. In a further embodiment,
steps 108, 110, and 112 may be repeated for any number of fields 86
of intermediate substrate 84.
[0042] Referring to FIGS. 4, 5, and 10, after forming patterned
layers 90a, 90b, 90c, and 90d on fields 86a, 86b, 86c, and 86d,
respectively, intermediate substrate 84 may be employed to form a
pattern in a final substrate 96. More specifically, at step 122,
polymeric material 34 may be positioned on final substrate 96
employing any of the methods mentioned above with respect to step
102 and FIG. 6. Final substrate 96 may comprise a plurality of
fields 98, shown as fields 98a-98d. However, in a further
embodiment, final substrate 96 may comprises any number of fields
98, i.e. 2, 4, 6, 8, or 9 fields. In the present embodiment, the
number of fields 98 of final substrate 96 may be substantially the
same as the number of fields 86 of intermediate substrate 84. To
that end, polymeric material 34 may be positioned on fields 98 of
final substrate 96. In an example, final substrate 96 may have a
thickness of equal to or greater than 4 mm.
[0043] At step 124, a desired spatial relationship may be obtained
between intermediate substrate 84 and final substrate 96 such that
polymeric material 34 on final substrate 96 may fill the desired
volume between intermediate substrate 84 and final substrate
96.
[0044] At step 126, polymeric material 34 positioned on final
substrate 96 may be solidified and/or cross-linked and intermediate
substrate 84 may be separated from polymeric material 34 positioned
on final substrate 96, defining a plurality of patterned layers 99
in each of fields 98, with each of patterned layers 99 being
substantially the same as dies 60 of mold 20, and thus, final
substrate 96 may be substantially the same as template 18.
[0045] Referring to FIGS. 4-6, in a second embodiment, it may be
desired to form template 18 from master template 62 in a single
patterning step. To that end, each of patterned layer 90 positioned
on fields 86 of intermediate substrate 84 may be substantially the
same as dies 60 of mold 20 and thus, intermediate substrate 84 may
be substantially the same as template 18. In the present example,
master template 62 may have a thickness of approximately 2.29 mm
and intermediate substrate 84 may have a thickness of 6.35 mm.
[0046] Referring to FIG. 11, in still a further embodiment,
substrate alignment marks 92 may be formed on intermediate
substrate 84 in a separate step. More specifically, substrate
alignment marks 92 may be formed on intermediate substrate 84 prior
to forming patterned layer 90 on intermediate substrate 84. To that
end, substrate alignment marks 92 may be formed employing a) an
optical lithography tool with accurate global inteferometry, such
as a 913 nm scanner lithography tool available from ASML of the
Netherlands or b) an optical lithography tool with excel
interferometry, such as the Nanoruler described at
http://www.sciencedaily.com/releases/2004/02/040203233840.htm,
which is incorporated herein by reference. As a result, alignment
between fields 86 of intermediate substrate 84 may be obtained,
i.e., field to field alignment.
[0047] Referring to FIGS. 3, 5, and 6, to that end, as described
above, mold 20 may have four dies associated therewith. However, as
mentioned above, mold 20 may have any number of dies associated
therewith, and thus, master template 62, intermediate substrate 84,
and final substrate 96 may scale according. As shown in FIG. 12,
master template 62 may have nine sections 64 associated therewith.
To that end, each of sections 64 of master template 62 may have a
pattern of alignment forming areas 78 and template alignment marks
80 proximate thereto, and more specifically, each section of
sections 64 may have a pattern of alignment forming areas 78 and
template alignment marks 80 differing from a pattern of alignment
forming areas 78 and template alignment marks 80 of surrounding
sections of sections 64. More specifically, sections 64a, 64c, 64e,
64g, and 64i may have a fifth pattern of alignment forming areas 78
and template alignment marks 80 proximate thereto and sections 64b,
64d, 64f, and 64h may have a sixth pattern of alignment forming
areas 78 and template alignment marks 80 proximate thereto, with
the fifth pattern of alignment forming areas 78 and template
alignment marks 80 being substantially the same as the first
pattern mentioned above with respect to FIG. 5, and the sixth
pattern of alignment forming areas 78 and template alignment marks
80 being substantially the same as the third pattern mentioned
above with respect to FIG. 5. Further, each of sections 64e, 64g,
and 64i may be patterned in the above-mentioned method analogous to
patterning of section 64c and each of sections 64f and 64h may be
patterned in the above-mentioned method analogous to patterning of
sections 64b and 64d.
[0048] Furthermore, it may be desired to minimize mechanical
distortions present in template 18 formed in any of the methods
mentioned above. To that end, master template 62, intermediate
substrate 84, and final substrate 96 may be substantially flat.
More specifically, master template 62, intermediate substrate 84,
and final substrate 96 may have a flatness better than 100 nm,
preferably better than 50 nm, preferably better than 20 nm and
further preferably better than 10 nm over the patterning area. To
further minimize the aforementioned mechanical distortions, inter
alia, minimize image placement errors, intermediate substrate 84
may conform to master template 62. To that end, master template 62,
intermediate substrate 84, and final substrate 96 may be positioned
upon a chuck analogous to substrate chuck 14 mentioned above with
respect to FIG. 1. To that end, a shape of master template 62,
intermediate substrate 84, and final substrate 96 may be determined
employing an air gauge system (not shown) coupled with an XY stage
(not shown); a laser distance sensor system (not shown) coupled
with an XY stage (not shown); or a full field 3D profiler (not
shown) as described in
http://www.zygo.com/?/products/metrology.htm, which is incorporated
by reference herein. Moreover, each of master template 62,
intermediate substrate 84, and final substrate 96 may be formed
from substantially the same material, with the material including
but not limited to, fused-silica and ultra-low-expansion glass.
Further, a difference in temperature between master template 62,
intermediate substrate 84, and final substrate 96 may be less than
0.05.degree. C., preferably less than 0.01.degree. C., and further
preferably less than 0.001.degree. C.
[0049] To further minimize, if not prevent, errors present formed
in any of the methods mentioned above, in the first embodiment
mentioned above, master template 62 may have an actuation system
coupled thereto analogous to actuation system 58 mentioned above
with respect to FIG. 1. In the second embodiment mentioned above,
final substrate 96 may have an actuation system coupled thereto
analogous to actuation system 58 mentioned above with respect to
FIG. 1.
[0050] The above-mentioned methods may be analogously employed in
formation of photomasks for photolithography. Photomasks are
typically 4.times. (the relief pattern of the photomask is 5 times
the size of the desired features to be formed on the substrate).
Advanced photomask that may be employed in photolithography with
KrF (248 nm) laser and ArF (193 nm) laser may further comprise
sub-resolution features that are smaller than the primary features.
These sub-resolution features may be also known as optical
proximity correction features or reticle enhanced features. The
sub-resolution features do not print; they are designed to enhance
the quality of the primary features. As mentioned above, the
primary features are 4.times.. For example, for a feature of the
size of 50 nm on the wafer, the primary photomask feature is 200
nm. The sub-resolution features may be as small as 1.times. or
smaller or as large as approaching 4.times.. Typically the small
sub-resolution features are about 1.5.times.; for 50 nm wafer
features, this translates to 75 nm on the photomask. The 4.times.
photomasks are for example are of size 100 mm by 100 mm for a 25 mm
by 35 mm wafer field size; and 104 mm by 132 mm for a 26 mm by 33
mm wafer field size. These fields typically have 2, 4, 6, or more
dies in them each of which have substantially the same pattern
requirements. Thus, the above-mentioned method may be analogously
employed in formation of photomasks for photolithography.
[0051] The embodiments of the present invention described above are
exemplary. Many changes and modifications may be made to the
disclosure recited above, while remaining within the scope of the
invention. Therefore, the scope of the invention should not be
limited by the above description, but instead should be determined
with reference to the appended claims along with their full scope
of equivalents.
* * * * *
References