U.S. patent application number 11/155093 was filed with the patent office on 2005-12-22 for method and apparatus for processing a semiconductor substrate.
Invention is credited to Hong, Jin-Gi, Park, Kun-Sang, Park, Young-Wook.
Application Number | 20050279282 11/155093 |
Document ID | / |
Family ID | 35479256 |
Filed Date | 2005-12-22 |
United States Patent
Application |
20050279282 |
Kind Code |
A1 |
Park, Kun-Sang ; et
al. |
December 22, 2005 |
Method and apparatus for processing a semiconductor substrate
Abstract
In a method of processing a semiconductor substrate, a source
gas is primarily excited into a first plasma state having a first
energy. The primarily excited source gas is provided to a process
chamber. The excited source gas in the process chamber is
secondarily excited into a second plasma state having a second
energy higher than the first energy. The secondarily excited source
gas contacts a semiconductor substrate to process the semiconductor
substrate.
Inventors: |
Park, Kun-Sang;
(Gyeonggi-do, KR) ; Park, Young-Wook;
(Gyeonggi-do, KR) ; Hong, Jin-Gi; (Gyeonggi-do,
KR) |
Correspondence
Address: |
MARGER JOHNSON & MCCOLLOM, P.C.
210 SW MORRISON STREET, SUITE 400
PORTLAND
OR
97204
US
|
Family ID: |
35479256 |
Appl. No.: |
11/155093 |
Filed: |
June 16, 2005 |
Current U.S.
Class: |
118/723MP ;
156/345.35; 156/345.38; 438/710 |
Current CPC
Class: |
C23C 16/34 20130101;
C23C 16/45538 20130101; C23C 16/14 20130101; C23C 16/45525
20130101; H01J 37/32357 20130101; H01J 37/32082 20130101; C23C
16/5096 20130101; C23C 16/452 20130101; H01J 37/32192 20130101;
C23C 16/45527 20130101 |
Class at
Publication: |
118/723.0MP ;
156/345.35; 156/345.38; 438/710 |
International
Class: |
C23F 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 16, 2004 |
KR |
2004-44265 |
Claims
What is claimed is:
1. A method of processing a substrate comprising: providing a
source in a first plasma state having a first energy to a process
chamber; exciting the source having the first energy in the process
chamber into a second plasma state having a second energy higher
than the first energy; and applying the source having the second
energy to the substrate.
2. The method of claim 1 wherein the process chamber is maintained
at a temperature below about 600.degree. C.
3. The method of claim 2 wherein the process chamber is maintained
at a temperature of about 200.degree. C. to about 500.degree.
C.
4. The method of claim 1 wherein the source is excited into the
first plasma state having the first energy using a remote
plasma-generating unit coupled to the process chamber, and the
source having the first energy is excited using a direct
plasma-generating unit within the process chamber.
5. The method of claim 1 wherein the source is excited into the
first plasma state having the first energy by applying microwave
energy to the source, and the source having the first energy is
excited by applying a high frequency energy to the source having
the first energy.
6. A method of processing a substrate comprising: providing a first
source in a first plasma state having a first energy to a process
chamber; exciting the first source having the first energy in the
process chamber into a second plasma state having a second energy
higher than the first energy; applying the first source having the
second energy to the substrate; providing a second source in a
third plasma state having a third energy to a process chamber;
exciting the second source having the second energy in the process
chamber into a fourth plasma state having a fourth energy higher
than the third energy; and applying the second source having the
fourth energy to the substrate;
7. The method of claim 6 wherein providing the first source,
exciting the first source, applying the first source, providing the
second source, exciting the second source and applying the second
source are repeated.
8. The method of claim 6 wherein the first source is excited into
the first plasma state having the first energy using a remote
plasma-generating unit coupled to the process chamber, the first
source having the first energy is excited using a direct
plasma-generating unit, the second source is excited into the third
plasma state having the third energy using the remote
plasma-generating unit, and the second source having the third
energy is excited using the direct plasma-generating unit.
9. The method of claim 6 wherein the first source is excited into
the first plasma state having the first energy by applying a
microwave energy to the first source, the first source having the
first energy is excited by applying a high frequency energy to the
first source having the first energy, the second source is excited
into the third plasma state having the third energy by applying a
microwave energy to the second source, and the second source having
the third energy is excited by applying a high frequency energy to
the second source having the third energy.
10. An apparatus to process a substrate comprising: a process
chamber having a space to process the substrate; a source-supplying
unit to supply a source to the process chamber; a remote
plasma-generating unit, arranged between the source-supplying unit
and the process chamber, to excite the source into a first plasma
state having a first energy; and a direct plasma-generating unit
arranged to excite in the process chamber the source having the
first energy into a second plasma state having a second energy
higher than the first energy.
11. The apparatus of claim 10 wherein the remote plasma-generating
unit comprises: a remote plasma-generating tube to receive the
source from the source-supplying unit; and a power source to apply
energy to the remote plasma-generating tube to excite the source
into the first plasma state having the first energy.
12. The apparatus of claim 11 wherein the power source comprises a
microwave generator.
13. The apparatus of claim 10 wherein the direct plasma-generating
unit comprises: a showerhead arranged to receive the source having
the first energy from the remote plasma-generating unit; and a
power source to apply an energy to the showerhead to excite the
source having the first energy into the second plasma state having
the second energy.
14. The apparatus of claim 13 wherein the power source comprises a
radio frequency power source.
15. The apparatus of claim 10 wherein the source-supplying unit
comprises: a first source-supplying line to supply a first source;
and a second source-supplying line to supply a second source.
16. The apparatus of claim 15 wherein the remote plasma-generating
unit is provided to at least one of the first and second
source-supplying lines.
17. The apparatus of claim 10 further comprising a second
source-supplying unit, connected to the direct plasma-generating
unit, to provide a second source to the process chamber.
18. The apparatus of claim 10 further comprising a heater to heat
the substrate.
19. The apparatus of claim 10 further comprising a chuck positioned
in the process chamber to support the substrate.
20. The apparatus of claim 10 further comprising a vacuum unit
coupled to the process chamber to exhaust byproducts generated in
processing the substrate.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35 USC .sctn. 119 to
Korean Patent Application No. 2004-44265, filed on Jun. 16, 2004,
the contents of which are herein incorporated by reference in their
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method and an apparatus
to process a semiconductor substrate. Embodiments of the present
invention relate to a method of processing a semiconductor
substrate using a source gas excited in plasma state and an
apparatus to process a semiconductor substrate using a source gas
excited in plasma state.
[0004] 2. Description of the Related Arts
[0005] Generally, a semiconductor device may be manufactured by,
for example, forming layers, patterns, and metal wiring. To form a
highly integrated, high capacity semiconductor device, plasma
energy states have been employed.
[0006] Generally, plasma is a phase of matter in which electrons,
ions and neutrons coexist with an overall electrically neutral
polarity. A source gas excited to a plasma state has a high
reactivity supporting precise semiconductor substrate processing.
To form a semiconductor structure of minute pattern or a high
aspect ratio, a source gas excited to a plasma state has been
used.
[0007] FIG. 1 (Prior Art) is a cross sectional view illustrating a
conventional apparatus for processing a semiconductor substrate
using plasma.
[0008] Referring to FIG. 1, a conventional apparatus 10 includes a
process chamber 20, a chuck 32, a heater 34, a showerhead 40, a
first gas supply line 52, a second gas supply line 54 and a high
frequency power supply 60.
[0009] Process chamber 20 provides a space to receive a
semiconductor substrate W for processing. Chuck 32 is located in
process chamber 20 to support semiconductor substrate W. Heater 34
is built into chuck 32 to heat semiconductor substrate W.
Showerhead 40 resides over semiconductor substrate W as positioned
on chuck 32.
[0010] First and second gas supply lines 52 and 54, respectively,
connect to showerhead 40. A source gas enters process chamber 20
via showerhead 40.
[0011] Power supply 60 provides high frequency power to showerhead
40 and thereby creates an electric field having a high potential
difference within process chamber 20. The source gas, exposed to
this electric field, becomes an excited source gas in a plasma
state.
[0012] As described above, electrons, ions and neutrons coexist in
the source gas when in a plasma state. The electrons in the source
gas break molecular bindings of other source gases to excite other
source gases into plasma state. As a result, process chamber 20 is
filled with source gases excited into the plasma state. Molecules
in the source gas, as excited into the plasma state, react with
each other to form a layer on semiconductor substrate W.
[0013] Another conventional apparatus used to process a
semiconductor substrate includes the above-mentioned conventional
apparatus 10 and, further, a remote plasma generator. The remote
plasma generator excites a source gas into plasma state. Showerhead
40 and high frequency power supply 60 excite a cleaning gas into
plasma state. Thus, two conventional apparatuses have substantially
similar elements except for a remote plasma generator.
[0014] To illustrate by example, a conventional method of forming a
titanium nitride layer using conventional apparatus 10 is
described.
[0015] A TiCl.sub.4 gas is provided to the process chamber 20
through first gas supply line 52. An NH.sub.4 gas enters process
chamber 20 through second gas supply line 54. The TiCl.sub.4 gas
and NH.sub.4 gas, being exposed to the high potential electric
field within chamber 20, achieve an excited plasma state. The
TiCl.sub.4 gas and NH.sub.4 gas in the excited plasma state react
to form a titanium nitride layer on semiconductor substrate W and,
as a byproduct, generate an HCl.sub.4 gas. In this method, process
chamber 20 and semiconductor substrate W therein reach a
temperature of no less than about 600.degree. C.
[0016] This conventional method using plasma states uses
significantly high reaction energies of the source gases as excited
in the plasma state and significantly high thermal energies for
successful processing. Unfortunately, under such high thermal
energies desirable characteristics of a semiconductor device may
deteriorate. When thermal energies are low, however, abnormal
phases may be generated in the semiconductor device. For example,
when the temperature of the deposition process is lowered the
reaction ratio between the TiCl.sub.4 gas and NH.sub.4 gas
undesirably reduces and larger amounts of chlorine molecules remain
in the titanium nitride layer. This can cause corrosion of the
titanium nitride layer and increase its resistance. As power from
high frequency power supply 60 increases to increase reaction
energies between the TiCl.sub.4 gas and NH.sub.4 gas, however, the
reaction ratio between the TiCl.sub.4 gas and NH.sub.4 gas may not
be increased to a desired level. Furthermore, an increase of power
can cause undesirable etching of the titanium nitride layer.
[0017] Accordingly, lowering process temperature has been a
desirable goal in manufacture of highly integrated, high capacity
semiconductor devices.
SUMMARY OF THE INVENTION
[0018] Embodiments of the present invention provide a method of
processing and an apparatus to process a semiconductor substrate
with high efficiency yet at a relatively lower processing
temperature.
[0019] In a method of processing a semiconductor substrate in
accordance with one embodiment of the present invention, a source
gas is primarily excited into a first plasma state having a first
energy. The primarily excited source gas enters a process chamber.
The excited source gas in the process chamber is secondarily
excited into a second plasma state having a second energy higher
than the first energy. The secondarily excited source gas is
applied to a semiconductor substrate to process the semiconductor
substrate.
[0020] In a method of processing a semiconductor substrate in
accordance with another embodiment of the present invention, a
first source gas is primarily excited into a first plasma state
having a first energy. The primarily excited first source gas
enters a process chamber. The primarily excited first source gas in
the process chamber is secondarily excited into a second plasma
state having a second energy higher than the first energy. The
secondarily excited first source gas is applied to a semiconductor
substrate to primarily process the semiconductor substrate. A
second source gas is primarily excited into a third plasma state
having a third energy. The primarily excited second source gas
enters the process chamber. The primarily excited second source gas
in the process chamber is secondarily excited into a fourth plasma
state having a fourth energy higher than the third energy. The
secondarily excited second source gas is applied to the
semiconductor substrate to secondarily process the semiconductor
substrate.
[0021] In a method of processing a semiconductor substrate in
accordance with still another embodiment of the present invention,
a first source gas is primarily excited into a first plasma state
having a first energy. The primarily excited first source gas
enters a process chamber. The primarily excited first source gas in
the process chamber is secondarily excited into a second plasma
state having a second energy higher than the first energy. The
secondarily excited first source gas is applied to a semiconductor
substrate to primarily process the semiconductor substrate. A
second source gas enters the process chamber. The second source gas
is excited into a third plasma state having a third energy lower
than the second energy. The excited second source gas is applied to
the semiconductor substrate to secondarily process the
semiconductor substrate.
[0022] In a method of processing a semiconductor substrate in
accordance with still another embodiment of the present invention,
a first source gas enters a process chamber. The first source gas
in the process chamber is excited into a first plasma state having
a first energy. The excited first source gas is applied to a
semiconductor substrate to primarily process the semiconductor
substrate. A second source gas is primarily excited into a second
plasma state having a second energy. The primarily excited second
source gas enters the process chamber. The primarily excited second
source gas in the process chamber is secondarily excited into a
third plasma state having a third energy higher than the second
energy. The secondarily excited second source gas is applied to the
semiconductor substrate to secondarily process the semiconductor
substrate.
[0023] An apparatus for processing a semiconductor substrate in
accordance with another embodiment of the present invention
includes a process chamber to receive therein a semiconductor
substrate. A source gas-supplying unit provides a source gas to the
process chamber. A remote plasma-generating unit resides between
the source gas-supplying unit and the process chamber to excite the
source gas into a first plasma state having a first energy. A
direct plasma-generating unit resides within the process chamber to
further excite the excited source gas into a second plasma state
having a second energy higher than the first energy.
[0024] According to certain embodiments of the present invention,
source gas excitation into the plasma state supports precise
semiconductor processing at a low temperature. Thus,
semiconductor-processing efficiency remarkably improves and failure
ratios in subsequent processes attenuate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The foregoing and other objects, features and advantages of
embodiments the invention will be apparent from the more particular
description of preferred aspects of embodiments of the invention,
as illustrated in the accompanying drawings in which like reference
characters refer to the like parts throughout the different views.
The drawings are not necessarily to scale, with an emphasis instead
upon illustrating principles of embodiments of the invention. In
the drawings, the thicknesses of layers are exaggerated for
clarity.
[0026] FIG. 1 is a cross sectional view illustrating a conventional
apparatus for processing a semiconductor substrate using
plasma.
[0027] FIG. 2 is a schematic cross sectional view illustrating an
apparatus to process a semiconductor substrate in accordance with a
first embodiment of the present invention.
[0028] FIG. 3 is a timing chart illustrating a method of processing
a semiconductor substrate using the apparatus in FIG. 2.
[0029] FIG. 4 is a schematic cross sectional view illustrating an
apparatus to process a semiconductor substrate in accordance with a
second embodiment of the present invention.
[0030] FIG. 5 is a timing chart illustrating a method of processing
a semiconductor substrate using the apparatus in FIG. 4.
[0031] FIG. 6 is a schematic cross sectional view illustrating an
apparatus to process a semiconductor substrate in accordance with a
third embodiment of the present invention.
[0032] FIG. 7 is a timing chart illustrating a method of processing
a semiconductor substrate using the apparatus in FIG. 6.
[0033] FIG. 8 is a flow chart illustrating a method of processing a
semiconductor substrate in accordance with a fourth embodiment of
the present invention.
[0034] FIG. 9 is a flow chart illustrating a method of processing a
semiconductor substrate in accordance with a fifth embodiment of
the present invention.
[0035] FIG. 10 is a flow chart illustrating a method of processing
a semiconductor substrate in accordance with a sixth embodiment of
the present invention.
[0036] FIG. 11 is a flow chart illustrating a method of processing
a semiconductor substrate in accordance with a seventh embodiment
of the present invention.
DESCRIPTION OF THE EMBODIMENTS
[0037] Embodiments of the present invention now will be described
more fully with reference to the accompanying drawings. As used
herein, it will be understood that when a first element, e.g., a
layer, a source, a region or a substrate, is referred to as being
"on", "onto", "applied to", or "contacts" in relation to a second
element, the first element can be directly on, onto, applied, or
contacting the second element or intervening elements therebetween
may also be present.
Embodiment 1
[0038] FIG. 2 is a schematic cross sectional view illustrating an
apparatus to process a semiconductor substrate in accordance with a
first embodiment of the present invention.
[0039] In FIG. 2, an apparatus 100 in accordance with the present
embodiment includes a process chamber 110, a chuck 120, a heater
130, a source-supplying unit 140, a direct plasma-generating unit
150, a remote plasma-generating unit 160 and a vacuum unit 170. In
process, direct plasma-generating unit 150 and remote
plasma-generating unit 160 operate in serially linked fashion.
[0040] Apparatus 100 may include a batch type chamber or
single-substrate type chamber. In the present illustration,
apparatus 100 includes a single type process chamber 110 but as
will be understood and appreciated by those skilled in the art a
batch type chamber can be substituted therefor.
[0041] Process chamber 110 may have a cylindrical shape and
establish a processing space therein to receive a semiconductor
substrate W. Chuck 120 supports semiconductor substrate W as
positioned in the processing space. Heater 130 heats semiconductor
substrate W and may be provided integrally relative to chuck 120.
Additionally, a plurality of halogen lamps (not shown) may be
provided, e.g., on an inner wall of process chamber 110, to heat
process chamber 110.
[0042] An exhaust line 112 at one end of the inner wall of process
chamber 110 connects to vacuum unit 170 by way of exhaust line 112.
Vacuum unit 170 exhausts byproducts and non-reacted gases generated
within camber 110 while processing semiconductor substrate W.
[0043] Direct plasma-generating unit 150 mounts at an upper face of
process chamber 110 and includes a showerhead 152 and a radio
frequency (RF) power source 154. Showerhead 152 lies opposite
semiconductor substrate W when upon chuck 120. RF power source 154
couples to showerhead 152.
[0044] Source-supplying unit 140 provides source gas to process
chamber 110 at showerhead 152. Source-supplying unit 140 includes a
first source tank 141, a second source tank 142 and a
source-supplying line 144. As may be appreciated, source-supplying
unit 140 may include additional source tanks as employed in a
particular semiconductor processing application.
[0045] Source-supplying line 144 extends from showerhead 152 and
couples to remote plasma-generating unit 160. Source-supplying line
144, extending upstream from remote plasma-generating unit 160,
diverges into a first diverged line 146 and a second diverged line
147. Alternatively, e.g., when source-supplying unit 140 includes
additional source tanks, source-supplying line 144 may diverge into
additional diverged lines, e.g., each corresponding to one source
tank.
[0046] First diverged line 146 connects to first source tank 141.
Second diverged line 147 connects to second source tank 142. Mass
flow controllers 149 lie in series along first and second diverged
lines 146 and 147, respectively.
[0047] Remote plasma-generating unit 160 includes a remote
plasma-generating tube 162 and a microwave generator 164 with tube
162 located between first source-supplying line 144 and first and
second diverged lines 146 and 147. Microwave generator 164 connects
to remote plasma-generating tube 162.
[0048] A utility tank 180 supplies a purge or cleaning gas to
process chamber 110 by connection to showerhead 152. Examples of
the purge or cleaning gas include, but are not limited to, an inert
gas, a hydrogen gas, and the like. Utility tank 180 connects to
showerhead 152 through a utility line 182. An additional mass flow
controller 149 lies along utility line 182. Alternatively, utility
tank 180 may connect to showerhead 152 by way of source-supplying
line 144.
[0049] A main controller (not shown) controls each mass flow
controller 149. Persons skilled in the art are familiar with
operation of such a main controller and further discussion thereof
is omitted.
[0050] Different sources for processing semiconductor substrate W
reside in first and second source tanks 141 and 142, respectively.
In particular, a first source resides in first source tank 141 and
a second source in second source tank 142. The first and second
sources may be held in solid, liquid or gaseous states, but
desirably discharged from first and second source tanks 141 and
142, respectively, in a gaseous state.
[0051] As described above, phases of the first and second sources
may vary diversely in operation of apparatus 100 and persons
skilled in the art will readily understand acceptable the phases of
the first and second sources from the following illustrations
without limiting implementation to particular examples shown
herein.
[0052] The first and second sources may be diversely selected in
processing semiconductor substrate W. For example, to form a
silicon oxide layer on semiconductor substrate W, a silane
(SiH.sub.4) gas serves as the first source and an oxygen (O.sub.2)
gas serves as the second source. To form a titanium layer on
semiconductor substrate W, a TiCl.sub.4 gas serves as the first gas
and a hydrogen (H.sub.2) gas serves as the second source. Also, to
form a titanium nitride layer on the semiconductor substrate W, a
TiCl.sub.4 gas serves as the first gas and an NH.sub.4 gas serves
as the second source.
[0053] Other processes applicable semiconductor substrate W under
embodiments of the present invention include but are not limited to
a deposition process, an etching process, a photolithography
process, a polishing process, and the like. Accordingly, first and
second sources may be selected from a broad variety of materials
accordingly to particular applications and processes as will be
appreciated and understood by those skilled in the art, and in
accordance with the variety of processes as disclosed in many known
and available publications
[0054] FIG. 3 is a timing chart illustrating a method of processing
a semiconductor substrate using the apparatus of FIG. 2.
[0055] In FIGS. 2 and 3, to form a titanium layer on semiconductor
substrate W, for example, TiCl.sub.4 gas serves as the first source
and hydrogen gas serves as the second source.
[0056] The TiCl.sub.4 gas originates from first source tank 141 and
flows to remote plasma-generating tube 162 through mass flow
controller 149. Microwave generator 164 applies microwave energy,
e.g., of about 2 kW to about 2.8 kW at a frequency of about 0.05
GHz to about 2.45 GHz, to remote plasma-generating tube 162 to
generate a first electric field with high potential difference in
remote plasma-generating tube 162. The first electric field thereby
excites the TiCl.sub.4 gas into a first plasma state having a first
energy.
[0057] The TiCl.sub.4 gas having the first energy flows from remote
plasma-generating tube 162 to showerhead 152 through
source-supplying line 144. RF power source 154 applies RF energy,
e.g., of about 50 W to about 2,000 W at a frequency of about 0.05
MHz to about 13.56 MHz, to showerhead 152 to generate a second
electric field having a high potential difference in showerhead
152. The second electric field excites the TiCl.sub.4 gas, already
at the first energy, into a second plasma state having a second
energy higher than the first energy. The TiCl.sub.4 gas is thereby
twice excited upon reaching the second energy.
[0058] The TiCl.sub.4 gas, at the second energy, contacts for a
time T1 semiconductor substrate W. Heater 130 heats semiconductor
substrate W at a temperature of below about 600.degree. C.
Conventionally, when semiconductor substrate W is heated at a
temperature of no less than about 600.degree. C., a layer on
semiconductor substrate W is deteriorated due to the high thermal
energy. The deteriorated layer may be deformed in a following
process.
[0059] Preferably, semiconductor substrate W has a lower
temperature. However, when processing semiconductor substrate W at
a temperature of below about 150.degree. C., a reaction ratio of
the TiCl.sub.4 gas may undesirably decrease. Accordingly,
processing semiconductor substrate W at a temperature of about
150.degree. C. to about 550.degree. C., more preferably about
200.degree. C. to about 500.degree. C., has been found desirable.
Those skilled in the art will appreciate suitable selection of a
processing temperature for semiconductor substrate W in relation to
the energy of the TiCl.sub.4 gas.
[0060] Heater 130 heats the surroundings of semiconductor substrate
W as well as semiconductor substrate W. Although illustrations of
embodiments of the present invention focus on the temperature of
semiconductor substrate W, it will be appreciated by persons
skilled in the art that an inside temperature of process chamber
110 may be substantially similar to that of semiconductor substrate
W.
[0061] Heated TiCl.sub.4 gas, having the second energy, is applied
to a surface of semiconductor substrate W to absorb TiCl.sub.x(x=1
to 4) on semiconductor substrate W. Vacuum unit 170 exhausts for a
time T2 a non-reacted TiCl.sub.4 gas and byproducts from process
chamber 110.
[0062] Hydrogen gas flows from second source tank 142 to remote
plasma-generating tube 162 through mass flow controller 149.
Microwave generator 164 applies a microwave energy, e.g., of about
2 kW to about 2.8 kW at a frequency of about 0.05 GHz to about 2.45
GHz, to remote plasma-generating tube 162 to generate a third
electric field with a high potential difference in remote
plasma-generating tube 162. The hydrogen gas is exposed to the
third electric field and thereby excited into a third plasma state
having a third energy. The third energy may be substantially
similar to or different from the first energy. Also, in the present
embodiment, the third energy is not necessarily related in sequence
or magnitude to the first energy.
[0063] The hydrogen gas, having the third energy, flows from remote
plasma-generating tube 162 to showerhead 152 through
source-supplying line 144. RF power source 154 applies an RF
energy, e.g., of about 50 W to about 2,000 W at a frequency of
about 0.05 MHz to about 13.56 MHz, to showerhead 152, thereby
generating a fourth electric field having a high potential
difference in showerhead 152. The hydrogen gas, having the third
energy, is exposed to the fourth electric field and excited
therefrom into a fourth plasma state having a fourth energy higher
than the third energy. In other words, the hydrogen gas is twice
excited upon reaching the fourth energy. Here, the fourth energy is
not necessarily related in sequence or magnitude relative to the
second energy.
[0064] The hydrogen gas, having the fourth energy, contacts for a
time T3 semiconductor substrate W. Heater 130 heats semiconductor
substrate W at a temperature of below about 600.degree. C. When
semiconductor substrate W is heated at a temperature of no less
than about 600.degree. C., a layer on semiconductor substrate W is
deteriorated due to the high thermal energy. Semiconductor
substrate W is heated preferably at a temperature of about
150.degree. C. to about 550.degree. C., more preferably about
200.degree. C. to about 500.degree. C. A suitable temperature of
semiconductor substrate W will be understood by persons skilled in
the art in accordance with the energy of the hydrogen gas.
[0065] The heated hydrogen gas having the fourth energy reacts with
TiClx (x=1 to 4) to generate an HCl gas. As a result, a titanium
layer is formed on semiconductor substrate W. Vacuum unit 170
exhausts for a time T4 any non-reacted TiCl.sub.4 gas and
byproducts from process chamber 110.
[0066] The process performed from time T1 to T4 corresponds to one
cycle. When such cycle repeats a selected number of iterations, the
thickness of the resulting titanium layer is precisely established
in units of atomic layer.
[0067] Conventionally, a deposition process using plasma may be
carried out at a temperature of no less than about 600.degree. C.
The temperature of semiconductor substrate W corresponds to a
processing temperature at which deposition occurs. Accordingly, the
temperature of semiconductor substrate W has great influence on
characteristics of a layer so deposited.
[0068] According to the present embodiment, however, the
temperature of semiconductor substrate W can be well below about
600.degree. C. The potential reduction of reaction ratio between
the sources, e.g., due to the decrease in temperature of
semiconductor substrate W, may be compensated by increased of
energies of the first and second sources.
[0069] Although a titanium layer formed by an atomic layer
deposition (ALD) process is illustrated an a example embodiment of
the present invention, persons skilled in the art will readily
appreciate application of various embodiments of the present
invention to, for example, an etching process, a photolithography
process, a polishing process, and the like.
Embodiment 2
[0070] FIG. 4 is a schematic cross sectional view illustrating an
apparatus for processing a semiconductor substrate in accordance
with a second embodiment of the present invention.
[0071] In FIG. 4, apparatus 200 includes architecture and
particular elements similar to those of apparatus 100, but with a
modified remote plasma-generating unit. FIG. 4 includes similar
reference numerals referring to such similar elements and further
discussion of such similar elements is omitted.
[0072] In FIG. 4, an apparatus 200 in accordance with the present
embodiment includes a process chamber 110, a chuck 120, a heater
130, a source-supplying unit 140, a direct plasma-generating unit
150, a remote plasma-generating unit 260 and a vacuum unit 170. In
operation, e.g., during substrate W processing, direct
plasma-generating unit 150 and remote plasma-generating unit 260
couple in serially linked fashion.
[0073] A source-supplying line 244 extending upstream from
showerhead 152 diverges into a first diverged line 246 and a second
diverged line 247. First diverged line 246 connects to first source
tank 141. Second diverged line 247 connects to second source tank
142. Mass flow controllers 149 each lie along first and second
diverged lines 246 and 247, respectively.
[0074] Remote plasma-generating unit 260 operates between first
source tank 141 and showerhead 152. Remote plasma-generating unit
260 includes a remote plasma-generating tube 262 and a microwave
generator 264. Remote plasma-generating tube 262 mounts along on
first diverged line 246. Microwave generator 264 couples to remote
plasma-generating tube 262.
[0075] In this particular embodiment, remote plasma-generating unit
260 applies to only first diverged line 246 and excites only the
first source into a plasma state. Thus, remote plasma-generating
unit 260 of this particular embodiment may have a scale and volume
less than that of remote plasma-generating unit 160 in Embodiment
1.
[0076] FIG. 5 is a timing chart illustrating a method of processing
a semiconductor substrate W using the apparatus of FIG. 4.
[0077] In FIGS. 4 and 5, a first source originates in first source
tank 141 and flows to remote plasma-generating tube 262 by way of
mass flow controller 149. Microwave generator 264 applies microwave
energy to remote plasma-generating tube 262 and generates a first
electric field having a high potential difference in remote
plasma-generating tube 262. The first electric field excites the
first source into a first plasma state having a first energy.
[0078] The first source, having the first energy, flows from remote
plasma-generating tube 262 to showerhead 152 through
source-supplying line 244. RF power source 154 applies RF energy to
showerhead 152 and generates a second electric field having a high
potential difference in showerhead 152. The first source, having
the first energy but exposed to the second electric field, becomes
excited into a second plasma state having a second energy higher
than the first energy.
[0079] The first source, having the second energy, applies for a
time T1 to semiconductor substrate W. Heater 130 heats
semiconductor substrate W at a temperature of below about
600.degree. C. Process temperature selection of semiconductor
substrate W is illustrated and described in Embodiment 1 and any
further illustrations and discussion with respect to temperature of
semiconductor substrate W are omitted.
[0080] The heated first source, having the second energy, contacts
a surface of the semiconductor substrate W and atoms in the first
source absorb onto semiconductor substrate W. Vacuum unit 170
exhausts for a time T2 any non-reacted first source and byproducts
from process chamber 110.
[0081] The second source flows from second source tank 142 to
showerhead 152 through source-supplying line 244. RF power source
154 applies RF energy to showerhead 152 and generates a third
electric field having a high potential difference in showerhead
152. The second source, having the second energy and exposed to the
third electric field, moves to a third plasma state having a third
energy lower than the second energy. Thus, the first source is
twice excited into the second plasma state while the second source
is once excited into the third plasma state. As a result, the third
energy of the second source may be lower than the second energy of
the first source.
[0082] The second source, having the third energy, contacts for a
time T3 the semiconductor substrate. Heater 130 heats semiconductor
substrate W at a temperature of below about 600.degree. C. The
temperature of semiconductor substrate W is illustrated and
discussed in Embodiment 1 and any further illustrations or
discussions thereof are omitted.
[0083] The heated second source, having the third energy, reacts
with atoms of the first source and forms a layer on semiconductor
substrate W. Vacuum unit 170 exhausts for a time T4 any non-reacted
second source and byproducts from process chamber 110.
[0084] According to the present embodiment, the first source is
twice excited and the second source is once excited. Accordingly,
the remote plasma-generating unit may have a relatively reduced
scale and a volume compared to that in Embodiment 1. Furthermore,
the increased energy of the first source alleviates potential
reduction of the reaction ratio between the sources, e.g.,
reduction due to decrease of the temperature of semiconductor
substrate W. As a result, apparatus 200 of the present embodiment
enjoys improved efficiency in semiconductor substrate
processing.
Embodiment 3
[0085] FIG. 6 is a schematic cross sectional view illustrating an
apparatus for processing a semiconductor substrate in accordance
with a third embodiment of the present invention.
[0086] An apparatus 300 in accordance with the present embodiment
includes elements substantially similar to those of apparatus 100
in Embodiment 1 except for a modified remote plasma-generating
unit. Thus, similar reference numerals refer to similar elements
and any further discussion of such similar elements will be
omitted.
[0087] In FIG. 6, apparatus 300 in accordance with the present
embodiment includes a process chamber 110, a chuck 120, a heater
130, a source-supplying unit 140, a direct plasma-generating unit
150, a remote plasma-generating unit 360 and a vacuum unit 170. In
operation, e.g., during substrate W processing, direct
plasma-generating unit 150 and remote plasma-generating unit 360
couple in serially linked fashion.
[0088] A source-supplying line 344 extends from showerhead 152 and
diverges into a first diverged line 346 and a second diverged line
347. First diverged line 346 connects to first source tank 141.
Second diverged line 347 connects to second source tank 142. Mass
flow controllers 149 reside each along first and second diverged
lines 346 and 347, respectively.
[0089] Remote plasma-generating unit 360 operates between second
source tank 142 and showerhead 152. Remote plasma-generating unit
360 includes a remote plasma-generating tube 362 and a microwave
generator 364. Remote plasma-generating tube 362 mounts along
second diverged line 347. Microwave generator 364 couples to remote
plasma-generating tube 362.
[0090] In the present embodiment, remote plasma-generating unit
360, as coupled only to second diverged line 347, excites only the
second source into a plasma state. Accordingly, remote
plasma-generating unit 360 of the present embodiment may have a
scale and volume less than that of remote plasma-generating unit
160 of Embodiment 1.
[0091] FIG. 7 is a timing chart illustrating a method of processing
a semiconductor substrate using the apparatus in FIG. 6.
[0092] In FIGS. 6 and 7, a first source flows from first source
tank 141 to showerhead 152 by way of mass flow controller 149. RF
power source 154 applies RF energy to showerhead 152 and generates
a first electric field having a high potential difference in
showerhead 152. The first electric field excites the first source
into a first plasma state having a first energy.
[0093] The first source, having the first energy, contacts for a
time T1 semiconductor substrate W. Heater 130 heats semiconductor
substrate W at a temperature of below about 600.degree. C. The
temperature of semiconductor substrate W is illustrated and
discussed in relation to Embodiment 1 and any further illustrations
and discussion with respect to the temperature of semiconductor
substrate W are omitted.
[0094] The first source, having the first energy, contacts a
surface of semiconductor substrate W and atoms in the first source
absorb onto semiconductor substrate W. Vacuum unit 170 exhausts for
a time T2 any non-reacted first source and byproducts from process
chamber 110.
[0095] The second source flows from second source tank 142 to
remote plasma-generating tube 362. Microwave generator 364 applies
microwave energy to remote plasma-generating tube 362 and generates
a second electric field having a high potential difference in
remote plasma-generating tube 362. The second source, being exposed
to the second electric field, achieves a second plasma state having
a second energy higher than the first energy therefor.
[0096] The second source, at the second energy, flows from remote
plasma-generating tube 362 to showerhead 152 through
source-supplying line 344. RF power source 154 applies RF energy to
showerhead 152 and generates a third electric field having a high
potential difference in showerhead 152. The second source, having
the second energy and exposed to the third electric field, reaches
a third plasma state having a third energy higher than the second
energy. The second source is thereby twice excited in reaching the
third plasma state.
[0097] The second source, having the third energy, contacts for a
time T3 semiconductor substrate W. The second source, having the
third energy, reacts with atoms of the first source to form a layer
on semiconductor substrate W. Vacuum unit 170 exhausts for a time
T4 any non-reacted second source and byproducts from process
chamber 110.
[0098] According to the present embodiment, the second source is
twice excited and the first source is once excited whereby remote
plasma-generating unit may have a relatively reduced scale and
volume as compared to that of Embodiment 1. Also, reaction ratio
reduction, e.g., between the sources due to a decreased
semiconductor substrate W temperature, is alleviated by the
increased energy of the second source. As a result, apparatus 300
of the present embodiment offers improved semiconductor processing
efficiency.
Embodiment 4
[0099] FIG. 8 is a flow chart illustrating a method of processing a
semiconductor substrate in accordance with a fourth embodiment of
the present invention.
[0100] In step S110 of FIG. 8, a source for processing a
semiconductor substrate is excited into a first plasma state having
a first energy. In step S120, the source having the first energy is
provided to a process chamber. In step S130, the source having the
first energy in the process chamber is excited into a second plasma
state having a second energy higher than the first energy. In step
S140, the source having the second energy is applied to a surface
of the semiconductor substrate to process the semiconductor
substrate.
[0101] The method of the present embodiment may be employed in a
deposition process, an etching process, an ashing process, a
photolithography process, a polishing process, and the like.
Particularly, the method of the present embodiment may be employed
in a plasma-enhanced chemical vapor deposition (PE-CVD) process, an
atomic layer deposition (ALD) process, a chemically etching
process, an etching process using ions, an etching process using
ion collisions and side protection layers.
[0102] The source may include at least one gas. Also, the source
may be diversely selected in accordance with various semiconductor
substrate processes. For example, to form a silicon oxide layer on
the semiconductor substrate, a silane (SiH.sub.4) gas and an oxygen
(O.sub.2) gas may be selected as the source. To form a titanium
layer on the semiconductor substrate, a TiCl.sub.4 gas and a
hydrogen (H.sub.2) gas may be selected as the source. To form a
titanium nitride layer on the semiconductor substrate, a TiCl.sub.4
gas and an NH.sub.4 gas may be selected as the source. To form a
tungsten layer on the semiconductor substrate, a WF.sub.6 gas and a
hydrogen gas may be selected as the source. Also, to ash a
photoresist film on the semiconductor substrate, an oxygen gas may
be selected as the source.
[0103] Particularly, in step S110, the source may be excited into
the first plasma state having the first energy using a remote
plasma-generating unit. The remote plasma-generating unit applies,
for example, microwave energy to the source to excite the source
into the first plasma state having the first energy, e.g.,
microwave energy having about 2 kW to about 2.8 kW and a frequency
of about 0.05 GHz to about 2.45 GHz. Also, when the source includes
at least two gases, the gases may be sequentially provided to the
remote plasma-generating unit.
[0104] Other energy sources, as well as a microwave source, may be
used to excite the source into the first plasma state having the
first energy as will be appreciated by those persons of skill in
the art.
[0105] In step S120, the source having the first energy is
provided, e.g., from outside the process chamber, to inside of the
process chamber.
[0106] In step S130, the source having the first energy is excited
into the second plasma state having the second energy using, for
example, a direct plasma-generating unit. The direct
plasma-generating unit applies, for example, RF energy to the
source and excites the source into a second plasma state having the
second energy. The RF energy may have about 50 W to about 2,000 W
at a frequency of about 0.05 MHz to about 13.56 MHz. Other devices,
e.g., as well as an RF energy device, may be used to excite the
source into the second plasma state as will be appreciated by those
skilled in the art.
[0107] In step S140, the source having the second energy contacts
the surface of the semiconductor substrate in processing the
semiconductor substrate. The semiconductor substrate is heated to a
temperature of below about 600.degree. C. When the semiconductor
substrate is heated at a temperature of no less than about
600.degree. C., a layer on the semiconductor substrate can
deteriorate due to high thermal energy. The deteriorated layer may
be undesirably deformed in a following process. Accordingly, the
semiconductor substrate has preferably a lower temperature during
processing. However, when the semiconductor substrate is heated at
a temperature of below about 150.degree. C., a reaction ratio of
the source may be reduced. As a result, the semiconductor substrate
is heated preferably at a temperature of about 150.degree. C. to
about 550.degree. C., more preferably about 200.degree. C. to about
500.degree. C. A processing temperature of the semiconductor
substrate may be selected by a person skilled in the art in
accordance with the energy of the source.
[0108] The process chamber as well as the semiconductor substrate
is heated. To suppress heat exchange between the process chamber
and the semiconductor substrate, the process chamber may have a
temperature substantially identical to that of the semiconductor
substrate.
[0109] Generally, a deposition process using plasma has been
carried out at a temperature of no less than about 600.degree. C.
The temperature of the semiconductor substrate corresponds to a
processing temperature at which the deposition occurs and the
temperature of the semiconductor substrate has a great influence on
characteristics of a layer.
[0110] According to embodiments of the present embodiment, the
temperature of the semiconductor substrate is below about
600.degree. C. Increased source energy compensates for potential
reduction of reaction ratio between the sources, e.g., due to the
decrease of the temperature of the semiconductor substrate. As a
result, precise semiconductor substrate processing is achieved.
Embodiment 5
[0111] FIG. 9 is a flow chart illustrating a method of processing a
semiconductor substrate in accordance with a fifth embodiment of
the present invention.
[0112] In step S210 of FIG. 9, a first source for processing a
semiconductor substrate is excited into a first plasma state having
a first energy. In step S215, the first source having the first
energy is provided to a process chamber. In step S220, the first
source having the first energy in the process chamber is excited
into a second plasma state having a second energy higher than the
first energy. In step S225, the first source having the second
energy is then applied to a surface of the semiconductor substrate
to process the semiconductor substrate. In step S230, a non-reacted
first source and byproducts are exhausted from the process
chamber.
[0113] In step S235, a second source for processing the
semiconductor substrate is excited into a third plasma state having
a third energy. In step S240, the second source having the third
energy is provided to the process chamber. In step S245, the second
source having the third energy is excited into a fourth plasma
state having a fourth energy higher than the third energy. In step
S250, the second source having the fourth energy is provided to the
surface of the semiconductor substrate to process the semiconductor
substrate. In step S255, a non-reacted second source and byproducts
are exhausted from the process chamber. The above steps S210 to
S255 may be repeated as indicated in S260.
[0114] As described above, the second energy is higher than the
first energy and the fourth energy is higher than the third energy.
The first energy and the third energy may be substantially similar
to each other or different from each other. Also, the second energy
and the fourth energy may be substantially similar to each other or
different from each other. In the present embodiment, the first
energy is not necessarily related in sequence or magnitude relative
to the third energy and the fourth energy is not necessarily
related in sequence or magnitude relative to the second energy.
[0115] The method of the present embodiment may be employed, for
example, in a deposition process, an etching process, an ashing
process, a photolithography process, a polishing process, and the
like. In the present embodiment, the method is exemplarily employed
in a deposition process for forming a titanium nitride layer by an
ALD process.
[0116] To form the titanium nitride layer on the semiconductor
substrate, a TiCl.sub.4 gas is used as the first source and an
NH.sub.4 gas is used as the second source. The TiCl.sub.4 gas
having the second energy is applied to the semiconductor substrate
to absorb TiClx (x=1 to 4) on the semiconductor substrate. The
semiconductor substrate is heated to a temperature of below about
600.degree. C., preferably about 150.degree. C. to about
550.degree. C. The temperature of the semiconductor substrate is
illustrated and discussed in relation to Embodiment 1 and need not
be further illustrated and discussed here.
[0117] The NH.sub.4 gas having the fourth energy is provided to the
surface of the semiconductor substrate. The NH.sub.4 gas is reacted
with TiClx (x=1 to 4) to generate an HCl gas. As a result, a
titanium nitride layer forms on the semiconductor substrate. The
semiconductor substrate is heated to a temperature of below about
600.degree. C., preferably about 150.degree. C. to about
550.degree. C. The temperature of the semiconductor substrate is
illustrated in Embodiment 1 and need not be further detailed
here.
[0118] By repeating steps S210 to S255, a titanium nitride layer is
formed successively in units of atomic layer.
[0119] Increased energies of the first and second sources
compensate for any reduction of the reaction ratio between the
first and second sources, e.g., reduced reaction ratio due to
decreased of the temperature of the semiconductor substrate. In
this manner, a semiconductor substrate is precisely processed.
Embodiment 6
[0120] FIG. 10 is a flow chart illustrating a method of processing
a semiconductor substrate in accordance with a sixth embodiment of
the present invention.
[0121] The method of the present embodiment is substantially
similar to that in Embodiment 5 except in regard to exciting a
second source.
[0122] In FIG. 10, steps S310-330 correspond to steps S210-S230 of
FIG. 9 as discussed above. In step S335, a second source is
provided to the process chamber, but not excited into a plasma
state.
[0123] In step S340, the second source is excited into a third
plasma state having a third energy. In step S345, the second source
having the third energy is applied to the surface of the
semiconductor substrate to process the semiconductor substrate. In
step S350, a non-reacted second source and byproducts are exhausted
from the process chamber. In step S355, steps S310 to S350 may be
repeatedly a selected number of times as desired.
[0124] The second energy is higher than the first energy and the
third energy may be lower than the second energy. Here, the third
energy may be substantially similar to or different from the first
energy. In the present embodiment, the first energy is not
necessarily related in sequence or magnitude relative to the third
energy.
[0125] The method of the present embodiment may be employed, for
example, in a deposition process, an etching process, an ashing
process, a photolithography process, a polishing process, and the
like. In the present embodiment, the method is exemplarily employed
in a deposition process for forming a titanium nitride layer by an
ALD process.
[0126] The reduction of the reaction ratio between the first and
second sources, e.g., due to a decreased temperature of the
semiconductor substrate, is compensated by an increased energy of
the first source. Also, power used to increase the energy of the
second source may be reduced relative to that of other embodiments.
Thus, the remote plasma-generating unit may have a reduced scale
volume for improved efficiency.
Embodiment 7
[0127] FIG. 11 is a flow chart illustrating a method of processing
a semiconductor substrate in accordance with a seventh embodiment
of the present invention.
[0128] The method of the present embodiment is substantially
similar to that in Embodiment 5 except in regard to exciting a
first source.
[0129] In step S410 of FIG. 11, a first source is provided to a
process chamber. In step S415, the first source in the process
chamber is excited into a first plasma state having a first energy.
In step S420, the first source having the first energy is applied
to a surface of the semiconductor substrate to process the
semiconductor substrate. In step S425, a non-reacted first source
and byproducts are exhausted from the process chamber.
[0130] In step S430, a second source is excited into a second
plasma state having a second energy. In step S435, the second
source having the second energy is provided to the process chamber.
In step S440, the second source having the second energy is excited
into a third plasma state having a third energy. In step S445, the
second source having the third energy is applied to the surface of
the semiconductor substrate to process the semiconductor substrate.
In step S450, a non-reacted second source and byproducts are
exhausted from the process chamber. The above steps S410 to S450
are repeated a selected number of times as desired.
[0131] The second energy may be higher than the first energy and
the third energy may be lower than the second energy. The third
energy may be substantially similar to or different from the first
energy. In this embodiment, the first energy is not necessarily
related in sequence or magnitude relative to the third energy.
[0132] The method of the present embodiment may be employed, for
example, in a deposition process, an etching process, an ashing
process, a photolithography process, a polishing process, and the
like. In the present embodiment, the method is exemplarily employed
in a deposition process for forming a titanium nitride layer by an
ALD process.
[0133] Reduced reaction ratio between the first and second sources,
e.g., due to decreased temperature of the semiconductor substrate,
is alleviated by increased energy of the second source. Power for
increasing the energy of the first source may be reduced relative
to other embodiments and, therefore, the remote plasma-generating
unit may have a reduced scale and volume for improved
efficiency.
[0134] According to embodiments of the present invention, the
source for processing the semiconductor substrate has increased
energy and the semiconductor substrate is precisely processed at a
relatively low temperature with error ratio in subsequent processes
reduced.
[0135] Also, the power for increasing the energy of the source may
be reduced so that efficiency of the process for processing the
semiconductor substrate may be improved.
[0136] While embodiments of the present invention have been
particularly shown and described by example, it will be understood
by those skilled in the art that various changes in form and
details may be made therein without departing from the spirit and
scope of the invention as defined by the appended claims.
* * * * *