U.S. patent application number 12/192077 was filed with the patent office on 2012-11-08 for system and method for critical dimension reduction and pitch reduction.
Invention is credited to Robert Charatan.
Application Number | 20120279656 12/192077 |
Document ID | / |
Family ID | 41680448 |
Filed Date | 2012-11-08 |
United States Patent
Application |
20120279656 |
Kind Code |
A9 |
Charatan; Robert |
November 8, 2012 |
SYSTEM AND METHOD FOR CRITICAL DIMENSION REDUCTION AND PITCH
REDUCTION
Abstract
A system for forming a feature includes forming a mask of a
first material on an underlying layer, the mask having an incorrect
profile. The profile of the mask is corrected and a feature is
formed in the underlying layer. A method of forming a feature is
also disclosed.
Inventors: |
Charatan; Robert; (Portland,
OR) |
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20100038032 A1 |
February 18, 2010 |
|
|
Family ID: |
41680448 |
Appl. No.: |
12/192077 |
Filed: |
August 14, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11173733 |
Jun 30, 2005 |
7427458 |
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12192077 |
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Current U.S.
Class: |
156/345.24 ;
257/E21.252 |
Current CPC
Class: |
G03F 7/40 20130101; H01L
21/0273 20130101 |
Class at
Publication: |
156/345.24 ;
257/E21.252 |
International
Class: |
H01L 21/306 20060101
H01L021/306 |
Claims
1. A system for forming devices in a substrate comprising: a
process chamber for enclosing a substrate for processing, the
process chamber coupled to a gas manifold and a controller; a
plurality of process gas sources fluidly coupled to the gas
manifold, the gas manifold coupled to the controller; and the
controller including a recipe, the recipe including: logic for
forming a mask on the substrate, the mask being formed of a first
material, wherein the logic for forming the mask includes logic for
forming a mask layer on the first layer and logic for forming at
least one opening in the mask layer, the at least one opening in
the mask layer having an incorrect profile of at least one side of
the opening or a bottom of the opening; logic for correcting the
incorrect profile of at least one side of the opening or a bottom
of the at least one opening in the mask layer includes at least one
of: logic for removing a bottom portion of at least one side of the
at least one opening in the mask layer such that the at least one
side is substantially perpendicular to top surface of the mask
layer; or logic for adding a second portion material to at least
one side of the opening in the mask layer such that the at least
one side of the opening is substantial perpendicular to a top
surface of the mask layer; and logic for forming a feature in the
first layer.
2. The system of claim 1, wherein the recipe further includes logic
for removing the mask layer from the first layer.
3. The system of claim 1, wherein the logic for forming the at
least one opening in the mask layer includes logic for forming the
at least one opening in the mask layer with a photolithographic
process wherein the photolithographic process is optimized for a
first critical dimension and wherein the at least one opening in
the mask layer has a second critical dimension that is
substantially less than the first critical dimension.
4. The system of claim 1, wherein the logic for forming the at
least one opening in the mask layer includes logic for forming the
at least one opening in the mask layer with a photolithographic
process wherein the photolithographic process is optimized for a
first density of openings and wherein the mask layer has a second
density of openings that is substantially greater than the first
density of openings.
5. The system of claim 1, wherein the logic for removing the bottom
portion of the at least one side of the opening in the mask layer
includes at least one of logic for applying a low pressure etch
process or logic for applying a selective deposition process.
6. The system of claim 5, wherein the low pressure etch process
includes an etch process pressure of less than about 70
milliTorr.
7. The system of claim 5, wherein the selective deposition process
includes an deposition process system pressure of greater than
about 50 milliTorr.
8. The system of claim 1, wherein the logic for adding a second
portion of material to the at least one side of the opening in the
mask layer includes at least one of logic for applying a low
pressure etch process or logic for applying a selective deposition
process.
9. The system of claim 1, wherein the recipe further includes logic
for narrowing the corrected profile of the at least one opening in
the mask layer.
10. The system of claim 9, wherein the logic for narrowing the
corrected profile of the opening in the mask layer includes logic
for adding a third portion of material to the at least one side of
the opening in the mask layer.
11. The system of claim 9, wherein the feature formed in the first
layer is substantially equal to or less than the narrowed opening
in the mask layer.
12. The system of claim 1, wherein correcting the profile of the at
least one opening in the mask layer includes removing a bottom
portion of at least one side of the at least one opening in the
mask layer such that the bottom of the opening is substantially
parallel to the top surface of the mask layer and that the bottom
of opening has a desired width.
13. A system for forming a feature in a substrate comprising: a
process chamber for enclosing a substrate for processing, the
process chamber coupled to a gas manifold and a controller; a
plurality of process gas sources fluidly coupled to the gas
manifold, the gas manifold coupled to the controller; and the
controller including a recipe, the recipe including: logic for
forming a mask on the substrate, the mask being formed of a first
material, wherein the logic for forming the mask includes logic for
forming a mask layer on the first layer and logic for forming at
least one opening in the mask layer, the at least one opening in
the mask layer having an incorrect profile of at least one side of
the opening or a bottom of the opening, wherein the at least one
opening in the mask layer is formed with a photolithographic
process, the photolithographic process is optimized for a first
critical dimension and wherein the at least one opening in the mask
layer has a second critical dimension that is substantially less
than the first critical dimension; logic for correcting the
incorrect profile of at least one side of the opening or a bottom
of the at least one opening in the mask layer includes: logic for
removing a bottom portion of at least one side of the at least one
opening in the mask layer such that the at least one side is
substantially perpendicular to top surface of the mask layer; and
logic for adding a second portion material to at least one side of
the opening in the mask layer such that the at least one side of
the opening is substantial perpendicular to a top surface of the
mask layer; and logic for forming a feature in the first layer.
14. The system of claim 13, wherein the bottom portion of at least
one side of the at least one opening in the mask layer is removed
from the at least one side of the opening in the mask layer
substantially simultaneously when the second portion of the
material is added to the at least one side of the opening in the
mask layer.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to forming devices
in a substrate, and more particularly, to methods and systems for
reducing the critical dimension and reducing the pitch in
lithographic systems and processes.
[0003] 2. Description of the Related Art
[0004] Reducing the device size (i.e., critical dimension of the
devices) and increasing the density of the devices (i.e., pitch
reduction) is a constant goal in semiconductor production. These
goals aid in reducing the power consumption and cost of the
semiconductor device being formed while also increasing the
performance of the semiconductor device. Unfortunately, the reduced
critical dimension and/or the reduced pitch often require new and
expensive equipment to achieve these goals. By way of example, if a
photolithographic system is optimized for forming devices having a
critical dimension of about 0.4 micron, and a desired critical
dimension is about 0.3 micron (an about 25% smaller critical
dimension) then the photolithographic system must be replaced
and/or extensively modified to accurately achieve the 0.3 micron
critical dimension.
[0005] Further, more devices having a 0.3 micron critical dimension
can be formed in the same area of the substrate (i.e., the pitch
can be reduced). By way of example, about 30 devices can be formed
in a width of about 24 micron having if each of the devices has a
0.4 micron critical dimension and about 0.4 micron pitch between
each device. In comparison, about 40 devices can be formed in the
same 24 micron width if each device has a 0.3 micron critical
dimension and about 0.3 micron pitch between each device. The
photolithographic system optimized for forming devices having the
critical dimension of about 0.4 micron pitch must be replaced
and/or extensively modified to accurately achieve the 0.3 micron
pitch.
[0006] As a result, the constant drive for reduced critical
dimension and decreased device pitch add to the capital cost of
producing semiconductors. In view of the foregoing, there is a need
for a system and method for extending the capabilities of a
photolithographic process so as to allow reducing the critical
dimension and reducing the pitch of the devices.
SUMMARY
[0007] Broadly speaking, the present invention fills these needs by
providing a system and method for extending the capabilities of a
photolithographic process so as to allow reducing the critical
dimension and reducing the pitch of the devices. It should be
appreciated that the present invention can be implemented in
numerous ways, including as a process, an apparatus, a system,
computer readable media, or a device. Several inventive embodiments
of the present invention are described below.
[0008] One embodiment provides a method of forming a feature. The
method includes forming a mask of a first material on an underlying
layer, the mask having an incorrect profile. Correcting the profile
of the mask and forming a feature in the underlying layer. The can
also include removing the mask.
[0009] Forming the mask on the underlying layer can include forming
the mask with a photolithographic process. The photolithographic
process is optimized for a first critical dimension and the mask
has a second critical dimension that is substantially less than the
first critical dimension.
[0010] Forming the mask on the underlying layer can include forming
the mask with a photolithographic process, the photolithographic
process is optimized for a first density and the mask has a second
density that is substantially greater than the first density.
[0011] Correcting the profile of the mask can include removing a
first portion of the sides of the mask. Removing a first portion of
the sides of the mask can include at least one of a low pressure
etch process or a selective deposition process. The low pressure
etch process can include an etch process pressure of less than
about 70 milliTorr. The selective deposition process can include a
deposition process pressure of greater than about 50 milliTorr.
[0012] Correcting the profile of the mask can include adding a
second portion material to the sides of the mask. Adding a second
portion of material to the sides of the mask can include at least
one of a low pressure etch process or a selective deposition
process.
[0013] The method can also include narrowing the corrected profile
of the mask. Narrowing the corrected profile of the mask can
include adding a third portion of material to the sides of the
mask. The feature formed in the underlying layer can be
substantially equal to or less than the narrowed mask.
[0014] Another embodiment provides a method of forming a feature.
The method includes forming a mask of a first material on an
underlying layer. The mask having an incorrect profile and the mask
is formed with a photolithographic process. The photolithographic
process is optimized for a first critical dimension and the mask
has a second critical dimension that is substantially less than the
first critical dimension. The profile of the mask is corrected
including removing a first portion of the sides of the mask and
adding a second portion of material to the sides of the mask. A
feature can be formed in the underlying layer. The first portion
can be removed from the sides of the mask substantially
simultaneously with the second portion of the material being added
to the sides of the mask.
[0015] Yet another embodiment provides a system for forming devices
in a substrate. The system includes a process chamber for enclosing
a substrate for processing. The process chamber coupled to a gas
manifold and a controller. Multiple process gas sources are fluidly
coupled to the gas manifold. The gas manifold coupled to the
controller and the controller includes a recipe. The recipe
including logic for correcting a profile of a mask formed on the
substrate, the mask being formed of a first material.
[0016] The logic for correcting the profile of the mask includes
logic for removing a first portion of the sides of the mask and
logic for adding a second portion of material to the sides of the
mask. The recipe can also include logic for narrowing the corrected
profile of the mask.
[0017] Other aspects and advantages of the invention will become
apparent from the following detailed description, taken in
conjunction with the accompanying drawings, illustrating by way of
example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The present invention will be readily understood by the
following detailed description in conjunction with the accompanying
drawings.
[0019] FIG. 1A is a cross-sectional view of a mask formed on a
semiconductor substrate, in accordance with one embodiment of the
present invention.
[0020] FIG. 1B is a cross-sectional view of features formed using
the mask, in accordance with one embodiment of the present
invention.
[0021] FIG. 1C is a cross-sectional view of features, in accordance
with one embodiment of the present invention.
[0022] FIG. 1D is a cross-sectional view of 0.3 micron mask formed
by the 0.4 micron-optimized photolithographic process, in
accordance with one embodiment of the present invention.
[0023] FIG. 1E is a cross-sectional view of the features formed by
the 0.3 micron mask, in accordance with one embodiment of the
present invention.
[0024] FIG. 1F is a detailed view of the profile of a mask, in
accordance with one embodiment of the present invention.
[0025] FIG. 2 is a flowchart of the method operations for
correcting the profile of the mask, in accordance with one
embodiment of the present invention.
[0026] FIGS. 3A and 3B are a cross-sectional view of features
formed in the underlying intermediate layer, in accordance with one
embodiment of the present invention.
[0027] FIG. 4 is a cross-sectional view of features formed in the
underlying intermediate layer, in accordance with one embodiment of
the present invention.
[0028] FIG. 5 is flowchart of the method-operations for narrowing a
mask, in accordance with one embodiment of the present
invention.
[0029] FIG. 6 is flowchart of the method-operations for gas
modulation for correcting a profile of a mask, in accordance with
one embodiment of the present invention.
[0030] FIG. 7 is a block diagram of a system, in accordance with
one embodiment of the present invention.
DETAILED DESCRIPTION
[0031] Several exemplary embodiments for a system and method for
extending the capabilities of a photolithographic process so as to
allow reducing the critical dimension and reducing the pitch of the
devices will now be described. It will be apparent to those skilled
in the art that the present invention may be practiced without some
or all of the specific details set forth herein.
[0032] The various embodiments described herein provide a system
and method for enhancing the performance of existing
photolithographic processes and systems. As a result, a
photolithographic process and system can be used to form
semiconductor devices having smaller critical dimension and
increased device density.
[0033] FIG. 1A is a cross-sectional view 100 of a mask 104A formed
on a semiconductor substrate 102, in accordance with one embodiment
of the present invention. The mask 104A is formed using a
photolithographic process optimized for forming devices having a
critical dimension (i.e., width) of about 0.4 micron or larger
features (i.e., a 0.4 micron process). The 0.4 micron process forms
features 104B in the mask material 104. Typically, the 0.4 micron
process includes a photolithographic sub process applied to a
photoresist mask material 104 (or other photosensitive material).
The exposed portions 104A of the mask material 104 are transformed
by exposure to the light. The non-exposed portions (not shown) are
removed in a subsequent cleaning process to form the features 104B
between the mask 104A.
[0034] Each of the removed portions 104B has a width of about 0.4
micron. Each of the removed portions 104B are separated by the mask
104A, that is equal to or larger than about 0.4 micron in
width.
[0035] The photolithographic process used to form the mask 104A is
optimized to form a mask having widths of about 0.4 micron or more
in width and a density of about 0.4 micron or more apart. As a
result, mask 104A has an optimum profile. The optimum profile mask
104A has sides that are substantially vertical. By way of example,
the sides of the mask 104A form an angle .theta. between about 75
and about 90 degrees to the top surface of the mask layer 104.
Further, substantially all of the material in the mask layer 104
has been removed in the removed portions such that the optimum
profile mask 104A have a bottom surface 104C that is substantially
parallel to the top surface of the mask layer 104.
[0036] FIG. 1B is a cross-sectional view 100' of features 102A
formed using the mask 104A, in accordance with one embodiment of
the present invention. The substrate 101 has an intermediate layer
102 formed thereon. The mask 104A is formed on the top surface of
the intermediate layer 102 as described above in FIG. 1A. An
etching process can be used to form features 102A in the
intermediate layer 102.
[0037] The shape of the mask 104A helps ensure the shape of the
resulting features 102A. By way of example, if the mask 104A has an
optimum profile then the resultant features 102A will in many
cases, also have an optimum profile of substantially the same
width. Similarly, if the mask 104A does not have an optimum profile
then the resultant features 102A will more than likely have a less
than optimum profile (e.g., less than optimum and/or inconsistent
depth and/or width).
[0038] FIG. 1C is a cross-sectional view 100'' of features 102A, in
accordance with one embodiment of the present invention. After the
mask 104A is used to form the features 102A as described above in
FIG. 1B, the mask is no longer needed. As shown in FIG. 1C, the
mask 104A has been removed. Typically the mask is removed by a
chemical mechanical planarization or a selective etching process or
any other suitable process to remove the mask 104A. The substrate
is then ready for subsequent processing. By way of example the
features 102A can be filled with a conductive material (e.g.,
copper, copper alloy or other conductive materials) to form a
conductive trace or a via or other device.
[0039] As the photolithographic process is optimized to form
features 102A having widths of about 0.4 micron or more in width
and about 0.4 micron or more apart, then the photolithographic
process cannot accurately form features having width or densities
less than about 0.4 micron. FIG. 1D is a cross-sectional view of
0.3 micron mask 108A formed by the 0.4 micron-optimized
photolithographic process, in accordance with one embodiment of the
present invention. FIG. 1F is a detailed view of the profile of a
mask 108A, in accordance with one embodiment of the present
invention. As the 0.4 micron-optimized photolithographic process is
not optimized to produce the mask 108A having widths of about 0.3
micron, the mask 108A does not have an optimum profile. By way of
example, the bottom 108C of the removed portions 108B is rounded or
may even be pointed and is not substantially parallel to the top
surface of the upper layer 104. Further, the mask 108A has sides
that form an angle .theta.' less than about 75 degrees to the top
surface of the mask layer 104.
[0040] FIG. 1E is a cross-sectional view 120' the features 118A-F
formed by the 0.3 micron mask 108A, in accordance with one
embodiment of the present invention. As shown, the features 118A-F
formed in the intermediate layer 102 have very inconsistent and
unsymmetrical profile, depth and width. Further, the features
118A-F undercut the mask 108A. Further still, the opening to the
features 118A-F is too narrow and has inconsistent widths. Once the
mask 108A is removed, the inconsistent width of the openings to the
features 118A-F will cause inconsistent filling of the features and
thus provide poor contact to the underlying layer 101 and/or poor
contact to a conductive layer that may be subsequently formed on
top of the filled features 118A-F.
[0041] In summary the mask 108A has undesirable, excess material
124 remaining at the bottom 108C of the removed portion 108B.
Further, too much material 122 has been removed from the top
portion of the mask 108A causing a rounding-off of the top edges of
the feature. If the mask 108A were used to attempt to form features
(e.g., features 102A) in the intermediate layer 102, the resulting
features would not have a predictable and optimum profile as the
profile of the mask 108A is not optimum.
[0042] One embodiment of the present invention provides a system
and method for correcting the profile of the mask 108A to an
optimum profile shape. Correcting the profile of the mask 108A can
include replacing the material 122 that was removed from the top
edge of the mask 108A. Correcting the profile of the mask 108A can
also include removing the undesirable excess material 124 remaining
at the bottom 108C of the removed portion 108B.
[0043] FIG. 2 is a flowchart of the method operations 200 for
correcting the profile of the mask 108A, in accordance with one
embodiment of the present invention. In an operation 205, a mask is
formed on an underlying layer. The mask can have an incorrect
profile (e.g., mask 108A).
[0044] In an operation 210, the profile of the mask 108A is
corrected. The profile can be corrected by adding material to the
top portion 122 of the mask 108A. Correcting the profile of the
mask 108A can also include removing additional material 124 from
the bottom portion of the mask 108A. The profile of the mask 108A
is corrected until the profile has a desirable profile. By way of
example, if the bottom of the mask 108C is sufficiently cleared of
material (e.g., similar to bottom 108C of FIG. 1E), however, too
much material 122 has been removed from the top portion of the mask
108A, then the only the portions of material 122 may be added to
the mask 108A to correct the profile. The profile of the mask 108A
can be corrected through gas modulation as will be described in
more detail below.
[0045] The profile of the mask 108A can be corrected by applying or
depositing a material with a non-uniform (e.g., depth dependent)
sticking coefficient to the sides of the mask. By way of example, a
depositing a material with a non-uniform sticking coefficient
material may build up on the top portions 122 of the mask faster
than at the bottom 108C of the mask and as a result, the
non-uniform sticking coefficient material can replace the material
122 at the top portions of the mask 108A.
[0046] Varying plasma conditions can change the amount of material
deposited at different locations within the opening of the mask
108B. For example, by increasing the hydrogen to fluorocarbon ratio
it is possible to change from a net etching to net depositing
plasma. Additional process parameters such as Argon flow and
pressure can be employed to control the relative amounts of
deposition and etching which occur at profile sidewalls (e.g.,
material 122) and bottom 108 (e.g., material 124). More generally,
to get a directional etch with little or no sidewall deposition, it
is beneficial to employ a low pressure (e.g., less than about 70
milliTorr), hydrogen free plasma while a net depositing condition
is achievable with a plasma process which utilizes higher pressure
and hydrogen flow. One representative example of a recipe which has
net etching characteristics is a plasma chamber pressure of about
30 milliTorr, with plasma power of about 800 watts at 27 MHz and 0
watts at 2 MHz, about 180 sccm Argon and about 150 sccm CF.sub.4.
In comparison, an example of a net depositing recipe is a plasma
chamber pressure of about 70 milliTorr, with plasma power of about
800 watts at 27 MHz and 400 watts at 2 MHz, about 240 sccm Argon
and about 75 sccm CF.sub.4, and about 100 sccm H.sub.2. In the
context of integrating reducing critical dimension and pitch, the
low pressure etch can remove more material (e.g., material 124)
from the bottom 108C of the opening in the mask than from the
sidewalls of the mask 108A. Removing the material 124 from the
bottom 108C of the opening in the mask 108A corrects at least a
portion of the profile of the opening 108B' in the mask. A
selective deposition process could be used instead of or in
combination with an etch process at a somewhat lower pressure. By
way of example, the selective deposition process could be applied
at about 70 milliTorr and the etch process be applied at a pressure
less than 70 milliTorr (e.g., about 50 milliTorr or between about
20 milliTorr and about 70 milliTorr but less than the pressure of
the selective deposition process). The selective deposition process
can deposit more or equivalent material on the sidewalls of the
mask 108A (e.g., material 122) than on the bottom 108C of the
opening in the mask. (For equivalent, what is meant is that if one
etches and removes more material from the bottom than the sidewall
and then deposits equivalent amounts of material on the sidewall
and bottom, then the net effect is still an etched feature with a
reduced opening 108B size.) Adding the additional material 122 to
the sidewalls of the mask 108A not only can iteratively reduce the
mask (and as a consequence to be etched feature) dimension, but
also can correct the profile of the opening 108B' in the mask.
Whether the low pressure etch process and/or the selective
deposition process is used is determined by the specific needs of
the mask 108A. By way of another example, if the top portion of the
profile of the mask 108A is acceptable, e.g., material 122 is
already substantially present), then the selective deposition may
be attenuated.
[0047] In an operation 215, a feature 302A is formed in the
underlying layer (e.g., layer 102) using the mask 108A' having the
corrected profile. The corrected profile of the mask 108A' allows
the features 302 to be formed with a desirable profile.
[0048] FIGS. 3A and 3B are a cross-sectional view 300 of features
302A formed in the underlying intermediate layer 102, in accordance
with one embodiment of the present invention. The 0.3 micron mask
108A was formed using a photolithographic process optimized for 0.4
micron device widths. The 0.3 micron mask 108A had an incorrect
profile such as shown in FIGS. 1D-E above. The profile of the mask
108A was corrected as described above to form mask 108A'. The
corrected profile mask 108A' is used to form features 302A in the
underlying intermediate layer 102.
[0049] As described above in FIGS. 1D-3B, an exemplary 0.4 micron
mask has been reduced to form a 0.3 micron mask. It should be
understood that similar reduction processes can be employed to
reduce other sizes of masks. By way of example a 0.25 micron mask
can be reduced to an about 0.15 micron mask. Similarly, a 0.5
micron mask could be reduced to an about 0.4 micron mask.
[0050] As described above in FIGS. 1D-3B, a mask can be formed with
an incorrect profile such as a mask formed with widths too small
for the photolithographic process employed. Then the profile of the
mask can be corrected so that it can be used to form features
(e.g., features 302A) that have similar smaller widths than
intended by the photolithographic process employed. The resulting
features can also be closer together than intended by the
photolithographic process employed.
[0051] FIG. 4 is a cross-sectional view 400 of a feature 402A
formed in the underlying intermediate layer 102, in accordance with
one embodiment of the present invention. FIG. 5 is flowchart of the
method-operations 500 for narrowing a mask, in accordance with one
embodiment of the present invention. In an operation 505, the mask
108A is formed. In an operation 510, the profile of the mask 108A
is corrected as described above.
[0052] In an operation 515, additional material 422 is added to the
sides of the mask 108A to further narrow the mask 108. By way of
example, as described above, a 0.4 micron photolithographic process
was used to form a 0.3 micron mask. The profile of the 0.3 micron
mask was corrected and then used to form features (e.g., features
302A of FIG. 3B above). The features 302A have substantially the
same width as the mask 108A' (e.g., about 0.3 micron). As shown in
FIG. 4, the additional material 422 can be added to the sidewalls
of the mask 108A to narrow the opening in the mask 108B'' to
substantially less than 0.3 micron (e.g., about 0.20 or 0.25 micron
width).
[0053] The opening in the mask 108B'' can be narrowed by gas
modulation. The opening in the mask 108B'' can be narrowed by
adding non-depth dependent, uniform sticking coefficient material
to the sides of the mask 108A.
[0054] As described above, varying plasma conditions can change the
amount of material deposited at different locations within the
feature. For example, a lower pressure (e.g., less than about 70
milliTorr) etch process, such as described above can be at least
somewhat directional in nature. The low pressure etch can remove
more material from the bottom 108C of the opening in the mask than
from the sidewalls of the mask 108A. A selective deposition process
could be used instead of or in combination with the lower pressure
etch process. The selective deposition can be deposit more material
on the sidewalls of the mask 108A than on the bottom 108C of the
opening in the mask. Adding the additional material 422 to the
sidewalls of the mask 108A reduces the width of the opening in the
mask 108B''.
[0055] In an operation 520, the narrowed opening 108A'' can be used
to form a similarly narrowed feature 402A. By way of example, if
the narrowed opening 108A'' has a width of about 0.25 micron then
the feature 402A can have a width of about 0.2 micron to about 0.25
micron.
[0056] FIG. 6 is flowchart of the method-operations 600 for gas
modulation for correcting a profile of a mask, in accordance with
one embodiment of the present invention. In an operation 605, a
substrate 101 is placed in a process chamber. The substrate has an
undesirable profile as described in FIGS. 1D-F above. The process
chamber can be any suitable process chamber (e.g., a plasma
chamber, etch chamber, deposition chamber, etc.).
[0057] In an operation 610, a first process is applied to the
substrate 101. By way of example and with reference to FIG. 1F
above, the first process can remove the excess material 124 from
the bottom 108C of the opening 108B in the mask 108A. The excess
material 124 can be removed in a selective etch process.
[0058] In an operation 615, a second process can be applied to the
substrate 101. By way of example and with reference to FIG. 1F
above, the second process can add the additional material 122 to
the top portion of the mask 108A. The additional material 122 can
be deposited in a deposition process. It should be understood that
the operations 610 and 615 can occur in any order and even be
iteratively applied to achieve a desired profile.
[0059] If, in an operation 620, the profile of the mask 108A is
corrected, then the method operations can end. Alternatively, if in
operation 620, the profile of the mask 108A is not yet corrected,
then the method operations can continue in operation 610. The
operations 610 and 615 can also occur substantially
simultaneously.
[0060] FIG. 7 is a block diagram of a system 700, in accordance
with one embodiment of the present invention. The system includes a
process chamber 702 coupled to a controller 710. The controller 710
includes one or more recipes 712 for controlling the processes
carried out in the process chamber 702. One or more process gas
sources 720A-N are coupled to the process chamber 702 through a gas
manifold 722. The gas manifold 722 is coupled to the controller
710. The gas manifold 722 allows the controller 710 to control the
pressure, flowrate, mixture and concentration of the process gases
from the process gas sources 720A-N in the processing chamber
702.
[0061] With the above embodiments in mind, it should be understood
that the invention may employ various computer-implemented
operations involving data stored in computer systems. These
operations are those requiring physical manipulation of physical
quantities. Usually, though not necessarily, these quantities take
the form of electrical or magnetic signals capable of being stored,
transferred, combined, compared, and otherwise manipulated.
Further, the manipulations performed are often referred to in
terms, such as producing, identifying, determining, or
comparing.
[0062] Any of the operations described herein that form part of the
invention are useful machine operations. The invention also relates
to a device or an apparatus for performing these operations. The
apparatus may be specially constructed for the required purposes,
or it may be a general-purpose computer selectively activated or
configured by a computer program stored in the computer. In
particular, various general-purpose machines may be used with
computer programs written in accordance with the teachings herein,
or it may be more convenient to construct a more specialized
apparatus to perform the required operations.
[0063] The invention can also be embodied as computer readable code
on a computer readable medium. The computer readable medium is any
data storage device that can store data which can thereafter be
read by a computer system. Examples of the computer readable medium
include hard drives, network attached storage (NAS), read-only
memory, random-access memory, CD-ROMs, CD-Rs, CD-RWs, magnetic
tapes, and other optical and non-optical data storage devices. The
computer readable medium can also be distributed over a network
coupled computer systems so that the computer readable code is
stored and executed in a distributed fashion.
[0064] It will be further appreciated that the instructions
represented by the operations in the above figures are not required
to be performed in the order illustrated, and that all the
processing represented by the operations may not be necessary to
practice the invention. Further, the processes described in any of
the above figures can also be implemented in software stored in any
one of or combinations of the RAM, the ROM, or the hard disk
drive.
[0065] Although the foregoing invention has been described in some
detail for purposes of clarity of understanding, it will be
apparent that certain changes and modifications may be practiced
within the scope of the appended claims. Accordingly, the present
embodiments are to be considered as illustrative and not
restrictive, and the invention is not to be limited to the details
given herein, but may be modified within the scope and equivalents
of the appended claims.
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