U.S. patent application number 13/486243 was filed with the patent office on 2013-12-05 for device manufacturing and cleaning method.
This patent application is currently assigned to TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD.. The applicant listed for this patent is Sheng-Chi Chin, Ting-Hao Hsu, Kuan-Wen Lin, Chi-Lun Lu, Ching-Wei Shen. Invention is credited to Sheng-Chi Chin, Ting-Hao Hsu, Kuan-Wen Lin, Chi-Lun Lu, Ching-Wei Shen.
Application Number | 20130323931 13/486243 |
Document ID | / |
Family ID | 49640705 |
Filed Date | 2013-12-05 |
United States Patent
Application |
20130323931 |
Kind Code |
A1 |
Lu; Chi-Lun ; et
al. |
December 5, 2013 |
DEVICE MANUFACTURING AND CLEANING METHOD
Abstract
A method of manufacturing is disclosed. An exemplary method
includes providing a substrate and forming one or more layers over
the substrate. The method further includes forming a surface layer
over the one or more layers. The method further includes performing
a patterning process on the surface layer thereby forming a pattern
on the surface layer. The method further includes performing a
cleaning process using a cleaning solution to clean a top surface
of the substrate. The cleaning solution includes tetra methyl
ammonium hydroxide (TMAH), hydrogen peroxide (H.sub.2O.sub.2) and
water (H.sub.2O).
Inventors: |
Lu; Chi-Lun; (Hsinchu City,
TW) ; Lin; Kuan-Wen; (Taichung City, TW) ;
Shen; Ching-Wei; (Taichung City, TW) ; Hsu;
Ting-Hao; (Hsinchu City, TW) ; Chin; Sheng-Chi;
(Jhubei City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lu; Chi-Lun
Lin; Kuan-Wen
Shen; Ching-Wei
Hsu; Ting-Hao
Chin; Sheng-Chi |
Hsinchu City
Taichung City
Taichung City
Hsinchu City
Jhubei City |
|
TW
TW
TW
TW
TW |
|
|
Assignee: |
TAIWAN SEMICONDUCTOR MANUFACTURING
COMPANY, LTD.
Hsinchu
TW
|
Family ID: |
49640705 |
Appl. No.: |
13/486243 |
Filed: |
June 1, 2012 |
Current U.S.
Class: |
438/703 ;
257/E21.249 |
Current CPC
Class: |
G03F 7/42 20130101; G03F
1/00 20130101; H01L 21/02057 20130101; G03F 7/425 20130101; G03F
7/423 20130101; H01L 21/311 20130101 |
Class at
Publication: |
438/703 ;
257/E21.249 |
International
Class: |
H01L 21/311 20060101
H01L021/311 |
Claims
1. A method of manufacturing comprising: forming one or more layers
over a substrate; forming a surface layer over the one or more
layers, patterning the surface layer; after patterning the surface
layer, performing a cleaning process using a cleaning solution to
clean a top surface of the substrate, wherein the cleaning solution
includes hydrogen peroxide (H.sub.2O.sub.2) and water (H.sub.2O),
and at least one of tetra methyl ammonium hydroxide (TMAH) and
tetrabutylammonium hydroxide (TBAH); forming a capping layer over
the one or more layers and under the surface layer; forming an
absorber layer over the capping layer and under the surface layer;
after patterning the surface layer, etching the absorber layer
using the surface layer; and after etching the absorber layer,
removing the surface layer.
2. (canceled)
3. The method of claim 1 further comprising: performing a rinsing
process using a surfactant, wherein the substrate is part of a
reticle and includes a material selected from the group consisting
of quartz, a ultra low expansion (ULE) material, and a low thermal
expansion material (LTEM), wherein the one or more layers include
alternating layers of molybdenum (Mo) and silicon (Si), wherein the
absorber layer includes silver oxide (Ag.sub.2O), wherein the
capping layer includes ruthenium (Ru), and wherein the
concentration of TMAH in the cleaning solution ranges from about
0.1 wt % to about 0.003 wt %.
4. The method of claim 1 wherein the cleaning process is performed
after the surface layer is removed by a stripping process, wherein
performing the cleaning process includes using a high frequency
system, wherein the cleaning solution is free of ammonia
(NH.sub.3), and wherein the cleaning solution includes a
surfactant.
5. The method of claim 1 wherein the cleaning process is performed
before the surface layer is removed, wherein the cleaning process
includes using UV irradiation to thereby remove the surface layer,
wherein the cleaning solution is free of ammonia (NH.sub.3), and
wherein the cleaning solution includes a surfactant.
6. (canceled)
7. The method of claim 1 further comprising: performing a rinsing
process using a surfactant, wherein the substrate is part of a
wafer and includes silicon (Si), wherein the one or more layers
include Si, and wherein the concentration of TMAH in the cleaning
solution ranges from about 0.1 wt % to about 0.003 wt %.
8. The method of claim 7 wherein the cleaning process is performed
after the surface layer is removed by a stripping process, wherein
the cleaning process includes using a high frequency system, and
wherein the cleaning solution includes a surfactant.
9. The method of claim 7 wherein the cleaning process is performed
before the surface layer is removed, wherein the cleaning process
includes using UV irradiation to thereby remove the surface layer,
and wherein the cleaning solution includes a surfactant.
10. A method of manufacturing comprising: forming a plurality of
layers on a substrate; forming a patterned surface layer having one
or more openings on the plurality of layers; etching a top layer of
the plurality of layers through the one or more openings of the
patterned surface layer, wherein etching the top layer of the
plurality of layers includes forming contamination debris on a
surface of the top layer of the plurality of layers; performing a
cleaning process using a cleaning solution to remove the
contamination debris, wherein the cleaning solution includes tetra
methyl ammonium hydroxide (TMAH), hydrogen peroxide
(H.sub.2O.sub.2) and water (H.sub.2O), wherein the concentration of
TMAH in the cleaning solution is less than about 2.38 wt %; after
etching the top layer of the plurality of layers and before
performing the cleaning process, removing the surface layer; and
after performing the cleaning process, performing a rinsing process
using a surfactant.
11. (canceled)
12. The method of claim 10 wherein removing the surface layer
during the cleaning process includes using UV irradiation.
13. The method of claim 10 wherein the cleaning solution includes a
surfactant.
14. A method comprising: providing a reticle including a substrate;
forming a plurality of layers on the substrate; forming an
intermediate layer on the plurality of layers; forming a patterned
surface layer having one or more openings on the intermediate
layer; etching the intermediate layer through the one or more
openings of the patterned surface layer, wherein etching the
intermediate layer includes forming contamination debris on a
surface of the intermediate layer; and performing a cleaning
process using a cleaning solution to remove the contamination
debris, wherein the cleaning solution includes tetra methyl
ammonium hydroxide (TMAH), hydrogen peroxide (H.sub.2O.sub.2) and
water (H.sub.2O), wherein the concentration of TMAH in the cleaning
solution ranges from about 0.1 wt % to about 0.003 wt %.
15. The method of claim 14 further comprising: after etching the
intermediate layer and before performing the cleaning process,
removing the surface layer; and after performing the cleaning
process, performing a rinsing process using a surfactant.
16. The method of claim 14 further comprising: after etching the
intermediate layer, removing the surface layer during the cleaning
process by using UV irradiation; and after performing the cleaning
process, performing a rinsing process using a surfactant.
17. The method of claim 14 wherein performing the cleaning process
includes using a high frequency system.
18. The method of claim 14 wherein the reticle is an extreme
ultraviolet (EVU) reticle, wherein the substrate includes a
material selected from the group consisting of an ultra low
expansion (ULE) material and a low thermal expansion material
(LTEM), wherein the plurality of layers include alternating layers
of molybdenum (Mo) and silicon (Si), and wherein the intermediate
layer is an absorber including silver oxide (Ag.sub.2O).
19. The method of claim 18 wherein the cleaning solution is free of
ammonia (NH.sub.3), and wherein the cleaning solution includes a
surfactant.
20. The method of claim 18 wherein the intermediate layer is less
than about 32 nanometers (nm) thick.
21. The method of claim 1, wherein the concentration of TMAH in the
cleaning solution is less than about 2.38 wt %.
22. The method of claim 10, wherein the cleaning solution includes
tetrabutylammonium hydroxide (TBAH).
23. The method of claim 14, wherein the cleaning solution includes
tetrabutylammonium hydroxide (TBAH).
Description
BACKGROUND
[0001] The semiconductor integrated circuit (IC) industry has
experienced rapid growth. In the course of the IC evolution,
functional density (i.e., the number of interconnected devices per
chip area) has generally increased while geometry size (i.e., the
smallest component (or line) that can be created using a
fabrication process) has decreased. This scaling down process
generally provides benefits by increasing production efficiency and
lowering associated costs. Such scaling down has also increased the
complexity of processing and manufacturing ICs and, for these
advances to be realized, similar developments in IC manufacturing
are needed.
[0002] For example, as the semiconductor industry has progressed
into nanometer technology process nodes in pursuit of higher device
density, higher performance, and lower costs, the requirement for a
cleaner surface during the manufacturing process is becoming more
stringent. The existing cleaning processes and cleaning solutions,
however, may result in critical dimension (CD) loss and damage to
layers exposed to the cleaning solution during the cleaning
process. As such, the cleanliness of a surface may be limited by
the potential of CD loss/damage. Accordingly, although existing
methods of manufacturing and cleaning devices have been generally
adequate for their intended purposes, they have not been entirely
satisfactory in all respects.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The present disclosure is best understood from the following
detailed description when read with the accompanying figures. It is
emphasized that, in accordance with the standard practice in the
industry, various features are not drawn to scale and are used for
illustration purposes only. In fact, the dimensions of the various
features may be arbitrarily increased or reduced for clarity of
discussion.
[0004] FIG. 1 is a flowchart of one embodiment of a method 100 for
manufacturing and cleaning a structure according to various aspects
of the present disclosure.
[0005] FIGS. 2 to 6 illustrate diagrammatic sectional views of one
embodiment of a structure at various stages, according to the
method 100 of FIG. 1.
[0006] FIG. 7 is a flowchart of one embodiment of a method 300 for
manufacturing and cleaning a structure according to various aspects
of the present disclosure.
[0007] FIGS. 8 to 11 illustrate diagrammatic sectional views of one
embodiment of a structure at various stages, according to the
method 300 of FIG. 7.
DETAILED DESCRIPTION
[0008] The following disclosure provides many different
embodiments, or examples, for implementing different features of
the invention. Specific examples of components and arrangements are
described below to simplify the present disclosure. These are, of
course, merely examples and are not intended to be limiting. For
example, the formation of a first feature over or on a second
feature in the description that follows may include embodiments in
which the first and second features are formed in direct contact,
and may also include embodiments in which additional features may
be formed between the first and second features, such that the
first and second features may not be in direct contact. In
addition, the present disclosure may repeat reference numerals
and/or letters in the various examples. This repetition is for the
purpose of simplicity and clarity and does not in itself dictate a
relationship between the various embodiments and/or configurations
discussed. Also, the components disclosed herein may be arranged,
combined, or configured in ways different from the exemplary
embodiments shown herein without departing from the scope of the
present disclosure. It is understood that those skilled in the art
will be able to devise various equivalents that, although not
explicitly described herein, embody the principles of the present
invention.
[0009] With reference to FIG. 1, a method 100 of cleaning a surface
of a structure begins at block 102 where a semiconductor substrate
is provided. Further, formed over the substrate is an underlying
layer, and formed over the underlying layer is a patterned surface
layer. At block 104, the patterned surface layer is used to etch at
least one underlying layer. At block 106, the patterned surface
layer is removed. The method 100 continues with block 108 where a
cleaning process is performed to remove contamination from the
surface of the structure. The cleaning process uses a cleaning
solution that may include tetra methyl ammonium hydroxide (TMAH),
hydrogen peroxide (H.sub.2O.sub.2) and water (H.sub.2O). In
alternative embodiments, the cleaning solution includes TBAH. At
block 110, a rinsing process is performed using a surfactant to
further remove contamination and/or cleaning solution. The method
100 continues with block 112 where fabrication is completed.
Additional steps can be provided before, during, and after the
method 100, and some of the steps described can be replaced or
eliminated for other embodiments of the method. The discussion that
follows illustrates various embodiments of a process according to
the method 100 of FIG. 1.
[0010] FIGS. 2 to 6 illustrate diagrammatic sectional views of one
embodiment of manufacturing and cleaning a structure 200 at various
stages, according to the method 100 of FIG. 1. In the present
embodiment, the structure 200 includes a semiconductor wafer. It is
understood that the structure 200 may be any structure that may
benefit from the present disclosure. Further, it is understood that
the structure 200 may include various devices and features, such as
other types of transistors such as bipolar junction transistors,
resistors, capacitors, diodes, fuses, etc. FIGS. 2-6 have been
simplified for the sake of clarity to better understand the
inventive concepts of the present disclosure. Additional features
can be added in the structure 200, and some of the features
described below can be replaced or eliminated in other embodiments
of the structure 200.
[0011] Referring to FIG. 2, the structure 200 includes a
semiconductor substrate 210. In the present embodiment the
semiconductor substrate 210 is a substrate of a semiconductor
wafer. The semiconductor substrate 210, for example, includes an
elementary semiconductor, such as silicon or germanium in a
crystalline structure; a compound semiconductor, such as silicon
germanium, silicon carbide, gallium arsenic, gallium phosphide,
indium phosphide, indium arsenide, and/or indium antimonide; or
combinations thereof.
[0012] Still referring to FIG. 2, formed over a surface of the
semiconductor substrate 210 are one or more underlying layers 212
including various materials such as conductive materials and
dielectric materials. The underlying layers 212 can include
patterned and unpatterned layers. Forming the underlying layers 212
may include single or multiple patterning and deposition processes,
etching processes, chemical mechanical polishing (CMP) processes, a
combination of these processes, or any other suitable process.
[0013] Still referring to FIG. 2, formed over the underlying layers
212 is a surface layer 214. The surface layer 214 may be a
patterned or an unpatterned layer. Depending on the purpose of the
surface layer 214, the surface layer 214 may include a dielectric
material, a conductive material, a combination thereof, or any
other suitable material. Forming the surface layer 214 may include
single or multiple patterning and deposition processes, wet/dry
etching processes, chemical mechanical polishing (CMP) processes, a
combination of these processes, or any other suitable process. In
the present embodiment, for example, the surface layer 214 is a
photoresist layer patterned by any suitable process. Patterning the
photoresist layer may include exposing the photoresist layer to a
pattern, performing a post-exposure bake process, and developing
the photoresist layer thereby forming a patterned photoresist
layer. The patterning may also be implemented or replaced by other
proper methods, such as maskless photolithography, electron-beam
writing, ion-beam writing, and molecular imprint. As such, in the
present embodiment, the surface layer 214 (photoresist) is a
temporary layer used in processing of the final device and which
will ultimately be removed. It is understood that the surface layer
214 may be a permanent layer that will be included in a final
device and may be formed of and/or include any other suitable
conductive and/or dielectric materials, according to design
requirements.
[0014] After the formation of the patterned surface layer 214,
contamination debris 216a such as organic particles, particles from
the patterned surface layer 214, particles from other layers,
particles from processing solutions, or other unwanted contaminants
may be present on exposed surfaces of the surface layer 214 or on
exposed surfaces of the underlying layers 212. The debris 216a may
be evenly or unevenly disbursed on all or some of the exposed
surfaces. Therefore contamination debris 216a may include the
debris 216 (FIG. 2)
[0015] Referring to FIG. 3, after the formation of the patterned
surface layer 214, part of one or more of the underlying layers 212
is removed by an etching process, thereby forming a pattern
thereon. The etching process uses the patterned surface layer 214
to define the area to be etched. The etching process may be a
single or a multiple step etching process. Further, the etching
process may include wet etching, dry etching, or a combination
thereof. The dry etching process may be an anisotropic etching
process. The etching process may use reactive ion etch (RIE) and/or
other suitable process. In one example, a dry etching process is
used to etch the underlying layers 212 that includes
fluorine-containing gas. In furtherance of the example, the
chemistry of the dry etch includes CF4, SF6, or NF3. After the
etching process, contamination debris 216b such as organic
particles, particles from the patterned surface layer 214,
particles from other layers, particles from processing solutions,
or other unwanted contaminants may be present on exposed surfaces
of the surface layer 214 or on exposed surfaces of the underlying
layers 212. The contamination debris 216b may be evenly or unevenly
disbursed on all or some of the exposed surfaces. The contamination
debris 216b may include the debris 216a of FIG. 2.
[0016] Referring to FIG. 4, in the present embodiment, after the
etching process, the surface layer 214 is removed by any suitable
process. For example, the surface layer 214 (photoresist) may be
removed by a liquid "resist stripper", which chemically alters the
resist so that it no longer adheres to the underlying hardmask.
Alternatively, surface layer 214 may be removed by a plasma
containing oxygen, which oxidizes it. Removing the surface layer
214 may further create debris 216 on exposed surfaces of the
underlying layers 212. In alternative embodiments, the surface
layer 214 is removed during the cleaning process, as disclosed
below. After the removing the surface layer 214, contamination
debris 216c such as organic particles, particles from the patterned
surface layer 214, particles from other layers, particles from
processing solutions, or other unwanted contaminants may be present
on exposed surfaces of the underlying layers 212. The contamination
debris 216c may be evenly or unevenly disbursed on all or some of
the exposed surfaces. The contamination debris 216c may include the
debris 216b of FIG. 3 and/or debris 216a of FIG. 2.
[0017] Referring to FIG. 5, a cleaning process is performed on the
structure 200 to remove debris 216 or other contamination. In the
present embodiment, performing the cleaning process includes
exposing the contaminated structure 200 to a cleaning solution 220
including tetra methyl ammonium hydroxide (TMAH). In alternative
embodiments, the cleaning solution 220 does not include TMAH but
rather includes tetrabutylammonium hydroxide (TBAH). In still
further embodiments, the cleaning solution 220 includes a
combination of both TMAH and TBAH. The present embodiment will
proceed with the cleaning solution including only TMAH, however, it
is understood that the description that follows is equally
applicable to the alternative embodiments that include TBAH or a
combination of both TMAH and TBAH. In the present embodiment, the
cleaning solution 220 further includes hydrogen peroxide
(H.sub.2O.sub.2) and water (H.sub.2O), thereby diluting the
cleaning solution 220 including TMAH. As such, the cleaning
solution 220 may be a solution having a concentration of TMAH of
less than about 2.38 wt %. For example, the cleaning solution 220
may be an ultra-dilute solution having a concentration of TMAH of
from about 0.1 wt % to about 0.003 wt %. Because the TMAH
concentration is less than 2.38 wt %, there is relatively
little/minimal etching of certain films, such as, for example, Si
of a wafer and MoSi film. Depending on the chemicals included and
concentration of the respective chemicals, the cleaning solution
220 may have a pH ranging from about 10 to about 14 and a
zeta-potential ranging from about -100 mV to about -160 mV.
[0018] In the present embodiment, the cleaning solution 220
includes a surfactant to enhance particle removal capability. The
surfactant may be cationic, antonic, or nonionic surfactant. The
surfactant may be a commercially available surfactant such as BASF
C-2101, or any suitable surfactant. When the surfactant is put into
the cleaning solution 220, it will readily dissolve if the
surfactant concentration is low. The surfactant concentration may
range from about 0.001 wt % to about 1.0 wt %.
[0019] The structure 200 may be exposed to the cleaning solution
220 by any appropriate processes. For example, the structure 200
may be dipped and/or immersed into the cleaning solution 220.
Alternatively, the cleaning solution 220 may be sprayed on the
exposed surface of the structure 200. In the present embodiment,
the structure 200 is dipped and/or immersed into the cleaning
solution 220. After the structure 200 has been exposed to the
cleaning solution 220, the debris 216 and/or other contaminants
have been substantially removed.
[0020] With continued reference to FIG. 5, in the present
embodiment, while the structure 200 is immersed into the cleaning
solution 220, the structure 200 is exposed to UV lamp 224
irradiation 226 to aid in the removal of debris 216c (which may
include debris 216b and 216a) and/or other contaminants. Further,
in embodiments where the surface layer 214 has not yet been
removed, the UV irradiation 226 functions to destroy and/or remove
the surface layer 214 (photoresist). In alternative embodiments,
the structure 200 is not exposed to the UV lamp 224 irradiation 226
and the surface layer 214 is not removed, thereby allowing the
surface layer 214 to be used in subsequent processing. In an
alternative embodiment, a cleaning process, substantially similar
to the cleaning process described above, is performed on the
structure 200 prior to the etching process of FIG. 3.
[0021] With reference to FIG. 6, in the present embodiment, after
exposing the structure 200 to the cleaning solution 220 and
removing the surface layer 214 (by either stripping or exposing the
surface layer 214 to the UV irradiation during the cleaning), the
cleaned structure 200 is rinsed with a surfactant 228 to remove any
cleaning solution 220 that remains and/or make the surface
hydrophobic, thereby preventing re-deposition of contaminants such
as debris/particles, or other unwanted materials. The surfactant
228 may be cationic, antonic, or nonionic. The surfactant 228, for
example, may be a surfactant such as BASF C-2101, or any suitable
surfactant. The surfactant 228 is sprayed by one or more nozzle 230
onto the surface of the structure 200 to thereby rinse the
structure 200. Alternatively, the structure 200 may be dipped
and/or immersed into the surfactant 228, or exposed to the
surfactant 228 by any suitable process, thereby rinsing the
structure 200. In alternative embodiments, the structure 200 is not
exposed to a surfactant after exposing the structure 200 to the
cleaning solution 220.
[0022] With reference to FIG. 7, a method 300 of cleaning a surface
of a structure is described below. The method 300 begins at block
302 where a substrate is provided. In the present embodiment, the
substrate is a substrate of a reticle/photomask. The substrate, for
example, may be the substrate of an EVU reticle or a DUV reticle.
Further, formed over the substrate is a metal layer, formed over
the metal layer is an absorber layer, and formed over the absorber
layer is a patterned surface layer. A capping layer may be
interposed between the metal layer and the absorber layer. At block
304, the patterned surface layer is used to etch the absorber
layer. At block 306, the patterned surface layer is removed. The
method 300 continues with block 308 where a cleaning process is
performed to remove contamination from the surface of the
structure. The cleaning process uses a cleaning solution that may
include tetra methyl ammonium hydroxide (TMAH), hydrogen peroxide
(H.sub.2O.sub.2) and water (H.sub.2O). In alternative embodiments,
the cleaning solution includes TBAH. At block 310, a rinsing
process is performed using a surfactant to further remove
contamination and/or cleaning solution. The method 300 continues
with block 312 where fabrication is completed. Additional steps can
be provided before, during, and after the method 300, and some of
the steps described can be replaced or eliminated for other
embodiments of the method. The discussion that follows illustrates
various embodiments of a process according to the method 300 of
FIG. 7.
[0023] FIGS. 8 to 11 illustrate diagrammatic sectional views of one
embodiment of a structure 400 at various stages, according to the
method 300 of FIG. 7. It is understood that the structure 400 may
be any structure that may benefit from the present disclosure.
Further, it is understood that the structure 400 may include
various other features. FIGS. 8-11 have been simplified for the
sake of clarity to better understand the inventive concepts of the
present disclosure. Additional features can be added in the
structure 400, and some of the features described below can be
replaced or eliminated in other embodiments of the structure
400.
[0024] Referring to FIG. 8, the structure 400 includes a substrate
410. In the present embodiment the substrate 410 is a substrate of
a reticle/photomask. The reticle/photomask may be an extreme
ultraviolet (EVU) photomask or a deep ultraviolet (DUV) photomask.
The substrate 410 may include a material such as quartz, a ultra
low expansion (ULE) material, a low thermal expansion material
(LTEM), or any other suitable material.
[0025] Still referring to FIG. 8, formed over a surface of the
substrate 410 is a metal layer (ML) 412 including one or more
layers of materials. For example, the ML 412 may include
alternating materials such as molybdenum (Mo) and silicon (Si), or
any other suitable materials. ML 412 may be formed by any suitable
processing including chemical vapor deposition (CVD), high density
plasma CVD (HDP-CVD), spin-on, physical vapor deposition (PVD or
sputtering), or other suitable methods. The CVD process, for
example, may use chemicals including Hexachlorodisilane (HCD or
Si2Cl6), Dichlorosilane (DCS or SiH2Cl2), Bis(TertiaryButylAmino)
Silane (BTBAS or C8H22N2Si) and Disilane (DS or Si2H6).
[0026] Still referring to FIG. 8, formed over ML 412 is a capping
layer 414 used to protect the underlying layers. The capping layer
414 may include a material such as ruthenium (Ru), or any other
suitable material. The capping layer 414 may be formed by any
suitable process such as chemical vapor deposition (CVD), high
density plasma CVD (HDP-CVD), spin-on, physical vapor deposition
(PVD or sputtering), or other suitable methods. The CVD process,
for example, may use chemicals including Hexachlorodisilane (HCD or
Si2Cl6), Dichlorosilane (DCS or SiH2Cl2), Bis(TertiaryButylAmino)
Silane (BTBAS or C8H22N2Si) and Disilane (DS or Si2H6).
[0027] With further reference to FIG. 8, formed over the capping
layer 414 is an absorber 416. The absorber 416 may include a
material such as silver oxide TaN/TaON, TaBn/TaBo, TaBn, Ag2O, or
any other suitable material. The absorber 416 may be formed having
a thickness T ranging from about 60 nanometers (nm) to about 10 nm.
In the present embodiment, the thickness T of the absorber 416 is
about 32 nm. The absorber 416 is formed by any suitable process
such as chemical vapor deposition (CVD), high density plasma CVD
(HDP-CVD), spin-on, physical vapor deposition (PVD or sputtering),
or other suitable methods. The CVD process, for example, may use
chemicals including Hexachlorodisilane (HCD or Si2Cl6),
Dichlorosilane (DCS or SiH2Cl2), Bis(TertiaryButylAmino) Silane
(BTBAS or C8H22N2Si) and Disilane (DS or Si2H6).
[0028] Formed over the absorber 416 is a surface layer 418. The
surface layer 418 may be a patterned or an unpatterned layer.
Forming the surface layer 418 may include single or multiple
patterning and deposition processes, wet/dry etching processes,
chemical mechanical polishing (CMP) processes, a combination of
these processes, or any other suitable process. In the present
embodiment, for example, the surface layer 418 is a photoresist
layer patterned by any suitable process. Patterning the surface
layer 418 may include exposing the surface layer 418 to a pattern,
performing a post-exposure bake process, and developing the surface
layer 418 (photoresist) thereby forming a patterned surface layer
418 (photoresist). The patterning may also be implemented or
replaced by other proper methods, such as maskless
photolithography, electron-beam writing, ion-beam writing, and
molecular imprint. As such, in the present embodiment, the surface
layer 418 (photoresist) is a temporary layer used in processing of
the final device and which will ultimately be removed. It is
understood that the surface layer 418 may be a permanent layer that
will be included in a final device and may be formed of and/or
include any other suitable conductive and/or dielectric materials,
according to design requirements.
[0029] After the formation of the patterned surface layer 418,
contamination debris 420a such as organic particles, particles from
the patterned surface layer 418, particles from other layers,
particles from processing solutions, or other unwanted contaminants
may be present on exposed surfaces of the surface layer 418 or on
exposed surfaces of the absorber 416. The contamination debris 420a
may be evenly or unevenly disbursed on all or some of the exposed
surfaces.
[0030] Referring to FIG. 9, after the formation of the patterned
surface layer 418, part of the absorber 416 is removed by an
etching process, thereby exposing the top surface of the capping
layer 414. The etching process uses the patterned surface layer 418
to define the area to be etched. The etching process may be a
single or a multiple step etching process. Further, the etching
process may include wet etching, dry etching, or a combination
thereof. The dry etching process may be an anisotropic etching
process. The etching process may use reactive ion etch (RIE) and/or
other suitable process. In one example, a dry etching process is
used to etch the absorber 416 that includes Cl.sub.2+O.sub.2 gas.
After the etching process, additional contamination debris 420b may
be formed and present on all or some of the exposed surfaces. The
contamination debris 420b may include the contamination debris 420a
of FIG. 8.
[0031] Referring to FIG. 10, in the present embodiment, after the
etching process, the surface layer 418 is removed by any suitable
process. For example, the surface layer 418 (photoresist) may be
removed by a liquid "resist stripper", which chemically alters the
resist so that it no longer adheres to the underlying hardmask.
Alternatively, surface layer 418 may be removed by a plasma
containing oxygen, which oxidizes it. Removing the surface layer
418 may further create debris 420 on exposed surfaces of the
absorber 416 and the capping layer 414. After removing the surface
layer 418, additional contamination debris 420c may be formed and
present on all or some of the exposed surfaces. The contamination
debris 420c may include the contamination debris 420b of FIG. 9
and/or contamination debris 420a of FIG. 8. In alternative
embodiments, the surface layer 418 is removed during the cleaning
process, as disclosed below.
[0032] Still referring to FIG. 10, a cleaning process is performed
on the structure 400 to remove debris 420c or other contamination.
In the present embodiment, performing the cleaning process includes
exposing the contaminated structure 400 to a cleaning solution 422
including tetra methyl ammonium hydroxide (TMAH). In alternative
embodiments, the cleaning solution 422 does not include TMAH but
rather includes tetrabutylammonium hydroxide (TBAH). In still
further embodiments, the cleaning solution 422 includes a
combination of both TMAH and TBAH. The present embodiment will
proceed with the cleaning solution including only TMAH, however, it
is understood that the description that follows is equally
applicable to the alternative embodiments that include TBAH or a
combination of both TMAH and TBAH. In the present embodiment, the
cleaning solution 422 further includes hydrogen peroxide
(H.sub.2O.sub.2) and water (H.sub.2O), thereby diluting the
cleaning solution 422 including TMAH. As such, the cleaning
solution 422 may a solution having a concentration of TMAH of less
than about 2.38 wt %. For example, the cleaning solution 422 may be
an ultra-dilute solution having a concentration of TMAH of from
about 0.1 wt % to about 0.003 wt %. Because the TMAH concentration
is an ultra-dilute solution, there is relatively little/minimal
etching of certain materials, such as, for example, Si of a wafer
and MoSi film, or other materials.
[0033] In the present embodiment, the cleaning solution 422 also
includes a surfactant to enhance particle removal capability. The
surfactant may be cationic, antonic, or nonionic surfactants. The
surfactant, for example, may be a surfactant such as BASF C-2101,
or any suitable surfactant. When the surfactant is put into the
cleaning solution 422, it will readily dissolve if the surfactant
concentration is low. The surfactant concentration may range from
about 0.001% wt to about 1.0 wt %. Depending on the chemicals
included and concentration of the respective chemicals, the
cleaning solution 422 may have a pH ranging from about 7 to about
14. Notably, because in the present embodiment the chemical
composition of the absorber 416 is Ag2O, using cleaning solution
422 that is ammonia (NH3) base chemical free may be beneficial as
NH3 reacts with the Ag2O material of the absorber 416 thereby
resulting in damage to the absorber 416. In alternative
embodiments, however, where no such concerns are present, the
cleaning solution 422 including NH3 may not have such adverse
affects.
[0034] With further reference to FIG. 10, the structure 400 is
exposed to the cleaning solution 400. The structure 400 may be
exposed to the cleaning solution 422 by any appropriate processes.
For example, the structure 400 may be dipped and/or immersed into
the cleaning solution 422. Alternatively, the cleaning solution 422
may be sprayed on the exposed surface of the structure 400. The
cleaning solution 422 may exposed to the structure 400 in
conjunction with other process. For example, the cleaning solution
422 may be used with a high frequency system such as an
ultrasonic/megasonic system to enhance particle removal without
damage to the pattern formed on the structure 400. Further, for
example, the cleaning solution 422 may be used during UV
irradiation to remove particles and/or the surface layer (e.g.,
photoresist) if still present. It is understood that both the UV
irradiation and the ultrasonic/megasonic system may be used
together (at the same time) or separately (at different times). In
the present embodiment, the structure 400 is exposed to the
cleaning solution 422 using a high frequency ultrasonic/megasonic
system 424. The ultrasonic/megasonic system 424 may include a unit
including a transducer, a quartz window, a media inlet that
receives the cleaning solution 422, and a nozzle tip that dispenses
the cleaning solution 422. The ultrasonic/megasonic system 424 may
provide vibration energy having a frequency range from about 100
kHz to about 9 MHz. Although the current embodiment depicts a
single ultrasonic/megosonic system 424 unit, it is understood that
the ultrasonic/megasonic system 424 may comprise multiple
ultrasonic/megasonic system 424 units.
[0035] Referring to FIG. 11, after the structure 400 has been
exposed to the cleaning solution 422 and the debris 420 and/or
other contaminants have been substantially removed, the structure
400 is rinsed with a surfactant 426. Surfactant 426 aids in the
removal of any cleaning solution 422 that remains and/or makes the
surface hydrophobic, thereby preventing re-deposition of
contaminants such as debris/particles, or other unwanted materials.
The surfactant 426 may be cationic, antonic, or nonionic. The
surfactant 426, for example, may be a surfactant such as BASF
C-2101, or any suitable surfactant. The surfactant 426 is sprayed
by one or more nozzle 428 onto the surface of the structure 400 to
thereby rinse the structure 400. Alternatively, the structure 400
may be dipped and/or immersed into the surfactant 426, or the
structure 400 may be exposed to the surfactant 426 by any suitable
process, thereby rinsing the structure 400. In alternative
embodiments, the structure 400 is not exposed to a surfactant after
exposing the structure 400 to the cleaning solution 422.
[0036] The above methods 100 and 300 provide for a cleaning process
using an improved cleaning solution including TMAH and H2O2 to form
and clean various structures such as wafers and
reticles/photomasks. The improved cleaning solution provides high
zeta-potential and thereby enhances the cleaning capability of the
cleaning process while providing for limited corrosion of
layers/films such as MoSi or Si, or other layers, thereby allowing
for improved critical dimensions (CD) and subsequent overlay
control. Also, because the cleaning process using the improved
cleaning solution does not require physical force (for example
brushes) to remove contaminants, loss/corrosion of layers/films is
further limited. Also, the improved cleaning solution may be
combined with a surfactant to further enhance particle removal such
as organic particles. Additionally, the improved cleaning solution
can be utilized at high temperatures, for example by using UV lamp
irradiation, during the cleaning process, thereby also allowing for
the removal of a photoresist in a single cleaning step. The clean
surface reduces manufacturing cost, cycle time, and provides for
higher production yields, when compared with traditional
manufacturing processes. Further, the methods described herein can
be easily implemented into current manufacturing process and
technology, thereby lowering cost and minimizing complexity.
Different embodiments may have different advantages, and no
particular advantage is necessarily required of any embodiment.
[0037] Thus, provided is a method. The exemplary method includes
providing a substrate and forming one or more layers over the
substrate. The method further includes forming a surface layer over
the one or more layers. The method further includes patterning the
surface layer. The method further includes performing a cleaning
process using a cleaning solution to clean a top surface of the
substrate. The cleaning solution includes tetra methyl ammonium
hydroxide (TMAH), hydrogen peroxide (H.sub.2O.sub.2) and water
(H.sub.2O).
[0038] In some embodiments, the method further includes forming a
capping layer over the one or more layers and under the surface
layer; forming an absorber layer over the capping layer and under
the surface layer; etching the absorber layer using the patterned
absorber layer; and after etching the absorber layer, removing the
surface layer. In further embodiments, the method may further
include performing a rinsing process using a surfactant, wherein
the substrate is part of a reticle and includes a material selected
from the group consisting of quartz, a ultra low expansion (ULE)
material, and a low thermal expansion material (LTEM), wherein the
one or more layers includes molybdenum (Mo) and silicon (Si),
wherein the absorber layer includes silver oxide (Ag2O), wherein
the capping layer includes ruthenium (Ru), and wherein the
concentration of TMAH in the cleaning solution ranges from about
0.1 wt % to about 0.003 wt %. In some embodiments the cleaning
process is performed after the surface layer is removed by a
stripping process, performing the cleaning process includes using a
high frequency system, the cleaning solution is free of ammonia
(NH3), and the cleaning solution includes a surfactant. In various
embodiments, the cleaning process is performed before the surface
layer is removed, the cleaning process includes using UV
irradiation to thereby remove the surface layer, the cleaning
solution is free of ammonia (NH3), and the cleaning solution
includes a surfactant.
[0039] In some embodiments, the method further includes etching a
top layer of the one or more layers using the patterned surface
layer; and after etching the top layer of the one or more layers,
removing the surface layer. In various embodiments, the method
further includes performing a rinsing process using a surfactant,
wherein the substrate is part of a wafer and includes silicon (Si),
wherein the one or more layers includes Si, and wherein the
concentration of TMAH in the cleaning solution ranges from about
0.1 wt % to about 0.003 wt %. In some embodiments, the cleaning
process is performed after the surface layer is removed by a
stripping process, the cleaning process includes using an high
frequency system, and the cleaning solution includes a surfactant.
In various embodiments, the cleaning process is performed before
the surface layer is removed, the cleaning process includes using
UV irradiation to thereby remove the surface layer, the cleaning
solution includes a surfactant.
[0040] Also provided is an alternative embodiment of a method. The
exemplary method includes providing a wafer including a substrate
and forming a plurality of layers on the substrate. The method
further includes forming a patterned surface layer having a
plurality of openings on the plurality of layers. The method
further includes etching a top layer of the plurality of layers
through the plurality of openings of the patterned surface layer,
wherein etching the top layer of the plurality of layers includes
forming contamination debris on a surface of the top layer of the
plurality of layers. The method further includes performing a
cleaning process using a cleaning solution to remove the
contamination debris, wherein the cleaning solution includes tetra
methyl ammonium hydroxide (TMAH), hydrogen peroxide
(H.sub.2O.sub.2) and water (H.sub.2O). the concentration of TMAH in
the cleaning solution ranges from about 0.1 wt % to about 0.003 wt
%.
[0041] In some embodiments, the method further includes after
etching the top layer of the plurality of layers and before
performing the cleaning process, removing the surface layer; and
after performing the cleaning process, performing a rinsing process
using a surfactant. In various embodiments, the method further
includes after etching the top layer of the plurality of layers,
removing the surface layer during the cleaning process by using UV
irradiation; and after performing the cleaning process, performing
a rinsing process using a surfactant. In some embodiments, the
cleaning solution includes a surfactant.
[0042] Also provided is yet another alternative method. The
exemplary method includes providing a reticle including a substrate
and forming a plurality of layers on the substrate. The method
further includes forming an intermediate layer on the plurality of
layers. The method further includes forming a patterned surface
layer having a plurality of openings on the intermediate layer. The
method further includes etching the intermediate layer through the
plurality of openings of the patterned surface layer. Etching the
intermediate layer includes forming contamination debris on a
surface of the intermediate layer. The method further includes
performing a cleaning process using a cleaning solution to remove
the contamination debris, wherein the cleaning solution includes
tetra methyl ammonium hydroxide (TMAH), hydrogen peroxide
(H.sub.2O.sub.2) and water (H.sub.2O). The concentration of TMAH in
the cleaning solution ranges from about 0.1 wt % to about 0.003 wt
%.
[0043] In some embodiments, the method further includes after
etching the intermediate layer and before performing the cleaning
process, removing the surface layer; and after performing the
cleaning process, performing a rinsing process using a surfactant.
In various embodiments, the method further includes after etching
the intermediate layer, removing the surface layer during the
cleaning process by using UV irradiation; and after performing the
cleaning process, performing a rinsing process using a
surfactant.
[0044] In some embodiments, performing the cleaning process
includes using an high frequency system. In various embodiments,
the reticle is an extreme ultraviolet (EVU) reticle, the substrate
includes a material selected from the group consisting of a ultra
low expansion (ULE) material and a low thermal expansion material
(LTEM), the plurality of layers include alternating layers of
molybdenum (Mo) and silicon (Si), and the intermediate layer is an
absorber including silver oxide (Ag2O). In further embodiments, the
cleaning solution is free of ammonia (NH3), and the cleaning
solution includes a surfactant. In certain embodiments, the
intermediate layer is less than about 32 nanometers (nm) thick.
[0045] The foregoing outlines features of several embodiments so
that those skilled in the art may better understand the aspects of
the present disclosure. Those skilled in the art should appreciate
that they may readily use the present disclosure as a basis for
designing or modifying other processes and structures for carrying
out the same purposes and/or achieving the same advantages of the
embodiments introduced herein. Those skilled in the art should also
realize that such equivalent constructions do not depart from the
spirit and scope of the present disclosure, and that they may make
various changes, substitutions, and alterations herein without
departing from the spirit and scope of the present disclosure.
* * * * *