U.S. patent application number 13/670477 was filed with the patent office on 2014-05-08 for method of forming pattern in substrate.
This patent application is currently assigned to Winbond Electronics Corp.. The applicant listed for this patent is WINBOND ELECTRONICS CORP.. Invention is credited to Lu-Ping Chiang.
Application Number | 20140127905 13/670477 |
Document ID | / |
Family ID | 50441389 |
Filed Date | 2014-05-08 |
United States Patent
Application |
20140127905 |
Kind Code |
A1 |
Chiang; Lu-Ping |
May 8, 2014 |
METHOD OF FORMING PATTERN IN SUBSTRATE
Abstract
A method of forming a pattern in a substrate is provided, in
which the substrate having a pattern region is provided first. A
plurality of stripe-shaped mask layers is formed on the substrate
in the pattern region. Each of at least two adjacent stripe-shaped
mask layers among the stripe-shaped mask layers has a protrusion
portion and the protrusion portions face to each other. A spacer is
formed on sidewalls of the stripe-shaped mask layers, wherein a
thickness of the spacer is greater than a half of a distance
between two of the protrusion portions. Subsequently, the
stripe-shaped mask layers are removed. An etching process is
performed by using the spacer as a mask to form trenches in the
substrate. Thereafter, the trenches are filled with a material.
Inventors: |
Chiang; Lu-Ping; (Hsinchu
City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WINBOND ELECTRONICS CORP. |
Taichung City |
|
TW |
|
|
Assignee: |
Winbond Electronics Corp.
Taichung City
TW
|
Family ID: |
50441389 |
Appl. No.: |
13/670477 |
Filed: |
November 7, 2012 |
Current U.S.
Class: |
438/675 |
Current CPC
Class: |
H01L 21/31144 20130101;
H01L 21/0338 20130101; H01L 21/0337 20130101; H01L 2924/0002
20130101; H01L 2924/0002 20130101; H01L 29/06 20130101; H01L
21/76816 20130101; H01L 2924/00 20130101; H01L 21/04 20130101; H01L
23/528 20130101 |
Class at
Publication: |
438/675 |
International
Class: |
H01L 21/04 20060101
H01L021/04 |
Claims
1. A method for forming a pattern in a substrate, comprising :
providing the substrate having a pattern region; forming a
plurality of stripe-shaped mask layers on the substrate in the
pattern region, wherein each of at least two adjacent stripe-shaped
mask layers among the stripe-shaped mask layers has a protrusion
portion and the protrusion portions face to each other; forming a
spacer on sidewalls of the stripe-shaped mask layers, wherein a
thickness of the spacer is greater than a half of a distance
between two of the protrusion portions; removing the stripe-shaped
mask layers; performing an etching process by using the spacer as a
mask to form trenches in the substrate; and filling the trenches
with a material.
2. The method for forming the pattern in the substrate as claimed
in claim 1, wherein a material of the stripe-shaped mask layers
comprises a photoresist or carbon.
3. The method for forming the pattern in the substrate as claimed
in claim 1, wherein an etching rate of the spacer is smaller than
an etching rate of the substrate during the etching process.
4. The method for forming the pattern in the substrate as claimed
in claim 1, wherein the material comprises a conductive
material.
5. The method for forming the pattern in the substrate as claimed
in claim 4, wherein the substrate comprises a dielectric
substrate.
6. The method for forming the pattern in the substrate as claimed
in claim 1, wherein the material comprises a dielectric material
and a conductive material formed on the dielectric material.
7. The method for forming the pattern in the substrate as claimed
in claim 6, wherein the substrate comprises a silicon
substrate.
8. The method for forming the pattern in the substrate as claimed
in claim 1, further comprising forming a block-shaped mask layer
outside the pattern region after forming the spacer and before
removing the stripe-shaped mask layers, wherein the block-shaped
mask layer is adjacent to terminals of the stripe-shaped mask
layers and covers a portion of the spacer at the terminals of the
stripe-shaped mask layers.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a semiconductor manufacturing
process. More particularly, the invention relates to a method for
forming a pattern in a substrate.
[0003] 2. Description of Related Art
[0004] In general, a method for forming a pattern in a substrate
includes forming a patterned mask layer on the substrate first.
Thereafter, by using the patterned mask layer as a mask, an etching
process is performed to form trenches in the substrate. Then, a
material of the predetermined pattern is filled in the
trenches.
[0005] With the tendency of device miniaturization and device
integration, the sizes of the line width and the space of the
devices are reduced. It is difficult to form the pattern having
required line width and space by using the above method.
Accordingly, a double patterning method is developed.
[0006] FIGS. 1A-1E are cross-sectional views showing a double
patterning method in the related art. First, referring to FIG. 1A,
a patterned photoresist layer 12 is formed on a substrate 10. The
patterned photoresist layer 12 has a pattern which has a ratio of
the line width to the space of 1:3. Then, referring to FIG. 1B, a
spacer 14 is formed on the sidewall of the patterned photoresist
layer 12. A thickness of the spacer 14 is equivalent to a line
width of the patterned photoresist layer 12. Subsequently,
referring to FIG. 1C, the patterned photoresist layer 12 is
removed. Thereafter, referring to FIG. 1D, using the spacer 14 as a
mask, an etching process is carried out to form trenches 16 in the
substrate 10. After that, referring to FIG. 1E, a conductive
material 18 is filled in the trenches 16. As such, a conductive
pattern having a ratio of the line width to the space of 1:1 is
formed in the substrate 10 (a top view thereof is shown in FIG.
2).
[0007] In the method, the patterned photoresist layer 12 has the
pattern with a ratio of the line width to the space of 1:3 so that
the patterned photoresist layer 12 can be easily formed if the
device size is smaller and smaller and the conductive pattern
having the ratio of the line width to the space of 1:1 is further
liable to be formed.
[0008] In some specific requirements, the conductive pattern needs
be modified. For example, one of the conductive layers in the
conductive pattern may require to be cutted. In specific, for
cutting one conductive layer depicted in FIG. 2 at where the
rectangle 20 is, a mask layer 22 as depicted in FIG. 1B needs be
formed at the location corresponding to the rectangle 20 before
performing the etching process depicted in FIG. 1C such that the
portion of the substrate 10 at the rectangle 20 is prevented from
being formed with a trench 16. Accordingly, the conductive pattern
with the cut pattern is formed after the conductive material 18 is
filled in the trenches 16.
[0009] However, the fabrication of the mask layer 22 requires the
use of an additional mask, which increases the fabrication cost. In
addition, for achieving a smaller and smaller line width, the
fabrication of the mask layer is quite difficult.
SUMMARY OF THE INVENTION
[0010] The present invention provides a method for forming a
pattern in a substrate, which efficiently reduces the fabrication
cost and the fabrication steps.
[0011] A method of forming a pattern in a substrate is provided, in
which the substrate having a pattern region is provided first. A
plurality of stripe-shaped mask layers is formed on the substrate
in the pattern region. Each of at least two adjacent stripe-shaped
mask layers among the stripe-shaped mask layers has a protrusion
portion and the protrusion portions face to each other. A spacer is
formed on sidewalls of the stripe-shaped mask layers, wherein a
thickness of the spacer is greater than a half of a distance
between two of the protrusion portions. Subsequently, the
stripe-shaped mask layers are removed. An etching process is
performed by using the spacer as a mask to form trenches in the
substrate. The trenches are then filled with a material.
[0012] According to the method for forming the pattern in the
substrate described in an embodiment of the present invention, a
material of the stripe-shaped mask layers includes a photoresist or
carbon.
[0013] According to the method for forming the pattern in the
substrate described in an embodiment of the present invention, an
etching rate of the spacer is smaller than an etching rate of the
substrate during the etching process.
[0014] According to the method for forming the pattern in the
substrate described in an embodiment of the present invention, the
material can be a conductive material and the substrate is, for
example, a dielectric substrate.
[0015] According to the method for forming the pattern in the
substrate described in an embodiment of the present invention, the
material can be a dielectric material and a conductive material
formed on the dielectric material and the substrate is, for
example, a silicon substrate.
[0016] According to the method for forming the pattern in the
substrate described in an embodiment of the present invention, a
block-shaped mask layer is further formed outside the pattern
region after forming the spacer and before removing the
stripe-shaped mask layers, wherein the block-shaped mask layer is
adjacent to terminals of the stripe-shaped mask layers and covers a
portion of the spacer at the terminals of the stripe-shaped mask
layers.
[0017] In light of the foregoing, according to the invention, the
stripe-shaped mask layers are firstly formed on the substrate and
at least two adjacent stripe-shaped mask layers respectively have a
protrusion portion. Thereafter, a spacer is formed on the sidewalls
of the stripe-shaped mask layers and the thickness of the spacer is
greater than a half of a distance between two of the protrusion
portions. Accordingly, a portion of the substrate located between
the two protrusion portions is covered by the spacer and is not
exposed. After performing the etching process, the portion of the
substrate between the two protrusion portions is not formed with
the trench. Therefore, the pattern subsequently formed in the
substrate can have the required cut pattern at the region between
the two protrusion portions, in which no additional mask is needed
to define the mask layer for protecting the portion of the
substrate between the two protrusion portions.
[0018] In order to make the aforementioned and other features and
advantages of the invention more comprehensible, embodiments
accompanying figures are described in detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIGS. 1A-1E are cross-sectional views showing a double
patterning method in the related art.
[0020] FIG. 2 is a schematic top view of FIG. 1E.
[0021] FIGS. 3A through 3D are schematic top views showing the
method for forming a pattern in a substrate according to one
embodiment of the invention.
[0022] FIGS. 4A through 4D are cross-sectional views along a line
I-I' respectively in FIGS. 3A through 3D.
[0023] FIGS. 5A through 5D are cross-sectional views along a line
II-II' respectively in FIGS. 3A through 3D.
DESCRIPTION OF EMBODIMENTS
[0024] FIGS. 3A through 3D are schematic top views showing the
method for forming a pattern in a substrate according to one
embodiment of the invention. FIGS. 4A through 4D are
cross-sectional views along a line I-I' respectively in FIGS. 3A
through 3D. FIGS. 5A through 5D are cross-sectional views along a
line II-II' respectively in FIGS. 3A through 3D.
[0025] First, referring concurrently to FIGS. 3A, 4A and 5A, a
substrate 100 having a pattern region 100a is provided. According
to the embodiment, the substrate 100 is exemplified as a dielectric
substrate, which can be a dielectric layer formed on a
semiconductor wafer or a dielectric layer in other structure. The
pattern region 100a is, for example, a region for wiring layout in
the substrate 100. A plurality of stripe-shaped mask layers 102 is
then formed on the substrate 100 in the pattern region 100a. A
material of the stripe-shaped mask layers 102 includes, for
example, photoresist or carbon. In addition, each of at least two
adjacent stripe-shaped mask layers 102 among the stripe-shaped mask
layers 102 has a protrusion portion 102a and the two protrusion
portions 102a face to each other. In the present embodiment, three
stripe-shaped mask layers 102 are illustrated and the two adjacent
stripe-shaped mask layers 102 at the most left side respectively
have a protrusion portion 102a. However, the invention is not
limited thereto and the number can be arbitrarily modified
according to the actual requirement by the person who has ordinary
skill in the art.
[0026] Next, referring to FIGS. 3B, 4B and 5B together, a spacer
104 is formed on sidewalls of the stripe-shaped mask layers 102.
The etching rate of the spacer 104 can be smaller than the etching
rate of the substrate 100 during the etching process. Therefore,
the spacer 104 can be served as an etching mask during etching the
substrate 100 in the subsequent etching process. A material of the
spacer 104 includes oxide, for example. Furthermore, a thickness of
the spacer 104 is greater than a half of a distance between the two
protrusion portions 102a. Accordingly, at least the region between
the two protrusion portions 102a is filled with the spacer 104,
i.e. at least the portion of the substrate 100 between the two
protrusion portions 102a is not exposed. Furthermore, in the
present embodiment, a block-shaped mask layer 106 is formed outside
the pattern region 100a after the formation of the spacer 104. The
block-shaped mask layer 106 is adjacent to the terminals of the
stripe-shaped mask layers 102 and covers a portion of the spacer
104 at the terminals of the stripe-shaped mask layers 102. The
block-shaped mask layer 106 is formed for preventing a portion of
the substrate 100 outside the pattern region 100a from being etched
in the subsequent etching process.
[0027] In the foregoing steps, the region between the two
protrusion portions 102a is filled with the spacer 104. Therefore,
no additional mask is required to define the mask layer covering
the portion of the substrate 100 between the two protrusion
portions 102a, which can reduce the fabrication steps and the
fabrication cost.
[0028] Next, refer to FIGS. 3C, 4C and 5C, the stripe-shaped mask
layers 102 are removed to expose a portion of the substrate 110.
Thereafter, by using the spacer 104 and the block-shaped mask layer
106 as a mask, an etching process is implemented to form trenches
108 in the substrate 100. Notably, in the present embodiment, the
spacer 104 is formed between the two protrusion portions 102a such
that the portion of the substrate 100 between the two protrusion
portions 102a is not etched during the etching process, i.e. the
trenches 108 are not formed between the two protrusion portions
102a.
[0029] After that, referring to FIGS. 3D, 4D and 5D, a material is
filled in the trenches 108. In the present embodiment, the material
filled in the trenches 108 is, for example, a conductive material.
Namely, the stripe-shaped conductive layers 110 capable of being
served as the wiring layers are formed after the conductive
material is filled in the trenches 108. The method for filling the
material into the trenches 108 includes, for example, applying and
coating the material on the whole substrate 100 to completely fill
the trenches 108 with the material and performing a planarization
process (such as the chemical-mechanical polishing process, CMP
process) for removing the material outside the trenches 108.
Notably, in the present embodiment, the portion of the substrate
100 between the two protrusion portions 102a does not have the
trenches 108 such that the conductive layers 110 are not formed in
the region between the two protrusion portions 102a after filling
the trenches 108 with the conductive material. In other words,
according to the present embodiment, a part of the stripe shaped
conductive layers 110 can have a cut portion. As shown in FIG. 3D,
the second one of the conductive layers 110 counted from the most
left side has the cut portion 110a.
[0030] In the present embodiment, only two adjacent stripe-shaped
mask layers have the protrusion portions respectively (i.e. the two
stripe-shaped mask layers 102 at the most left side in FIG. 3A and
3B), and thus one conductive layer having the cut portion is
formed. However, the invention is not limited thereto and a person
who has ordinary skill in the art can form a plurality of
conductive layers with the cut portion according to the above
method.
[0031] On the other hand, according to the present embodiment, the
substrate 100 is exemplified as a dielectric substrate and the
material filled in the trenches 108 is a conductive material, which
is, however, not limited in the present invention. In an
alternative embodiment, the substrate 100 can be a silicon
substrate (such as a semiconductor wafer) and the material filled
in the trenches 108 can be a dielectric material and a conductive
material formed on the dielectric material. Namely, the trenches
108 can be formed with the gate insulation layer (dielectric
material) and the gate (conductive material) of a transistor.
[0032] Although the invention has been described with reference to
the above embodiments, it will be apparent to one of the ordinary
skill in the art that modifications to the described embodiment may
be made without departing from the spirit of the invention.
Accordingly, the scope of the invention will be defined by the
attached claims not by the above detailed descriptions.
* * * * *