U.S. patent application number 10/514017 was filed with the patent office on 2005-09-15 for plasma processing system, plasma processing method, plasma film deposition system, and plasma film deposition method.
This patent application is currently assigned to MITSUBISHI HEAVY INDUSTRIES, LTD.. Invention is credited to Inoue, Masahiko, Matsuda, Ryuichi, Shimazu, Tadashi.
Application Number | 20050202183 10/514017 |
Document ID | / |
Family ID | 30002232 |
Filed Date | 2005-09-15 |
United States Patent
Application |
20050202183 |
Kind Code |
A1 |
Matsuda, Ryuichi ; et
al. |
September 15, 2005 |
Plasma processing system, plasma processing method, plasma film
deposition system, and plasma film deposition method
Abstract
A plasma film deposition apparatus (plasma processing apparatus)
is disclosed, which includes a second antenna 11b disposed around
an antenna 11a and located outwardly of a ceiling surface, and
which supplies the second antenna 11b with an electric current
flowing in a direction opposite to the direction of an electric
current supplied to the antenna 11a by power supply means, whereby
lines of magnetic force, F2, heading in a direction opposite to the
direction of lines of magnetic force, F1, appearing at the site of
the antenna 11a are generated at the site of the second antenna
11b. Thus, the magnetic flux density in the direction of the wall
surface is lowered, even when a uniform plasma is generated in a
wide range within a tubular container 2.
Inventors: |
Matsuda, Ryuichi;
(Takasago-shi, JP) ; Shimazu, Tadashi;
(Takasago-shi, JP) ; Inoue, Masahiko; (Kobe-shi,
JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Assignee: |
MITSUBISHI HEAVY INDUSTRIES,
LTD.
Tokyo
JP
|
Family ID: |
30002232 |
Appl. No.: |
10/514017 |
Filed: |
December 16, 2004 |
PCT Filed: |
June 17, 2003 |
PCT NO: |
PCT/JP03/07650 |
Current U.S.
Class: |
427/569 ;
118/723I; 216/68; 427/571 |
Current CPC
Class: |
H01J 37/321 20130101;
C23C 16/507 20130101 |
Class at
Publication: |
427/569 ;
118/723.00I; 216/068; 427/571 |
International
Class: |
C03C 015/00; H05H
001/24; C23F 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 19, 2002 |
JP |
2002-178129 |
Dec 3, 2002 |
JP |
2002-351250 |
Claims
1-16. (canceled)
17. A plasma processing apparatus in which a flat ring-shaped
antenna is disposed at a top of a ceiling surface of a processing
chamber, power is supplied by power supply means to generate a
plasma within the processing chamber, and processing is applied to
a surface of a substrate by atoms and molecules excited and
activated there, comprising a second antenna located outwardly of
the ceiling surface and disposed around the antenna, and second
power supply means for supplying the second antenna with an
electric current flowing in a direction opposite to a direction of
an electric current supplied to the antenna.
18. The plasma processing apparatus according to claim 17, wherein
the power supply means and the second power supply means are an
identical alternating current power source.
19. The plasma processing apparatus according to claim 17, wherein
connection between an alternating current power source as the power
supply means and the antenna, and connection between an alternating
current power source as the second power supply means and the
second antenna are in an identical direction, and phase changing
means is provided for rendering a phase of the alternating current
power source as the power supply means and a phase of the
alternating current power source as the second power supply means
opposite to each other.
20. The plasma processing apparatus according to claim 17, wherein
connection between an alternating current power source as the power
supply means and the antenna, and connection between an alternating
current power source as the second power supply means and the
second antenna are in opposite directions.
21. The plasma processing apparatus according to claim 17, wherein
the processing of the surface of the substrate is film deposition
for producing a film on the surface of the substrate by the excited
and activated atoms and molecules.
22. A plasma processing method which supplies power from above a
top of a ceiling surface of a processing chamber to generate a
plasma within the processing chamber, and applies processing to a
surface of a substrate by atoms and molecules excited and activated
there, comprising generating an electric current, which flows in a
direction opposite to a direction of an electric current supplied
for generation of the plasma, outwardly of the ceiling surface to
apply the processing.
23. A plasma film deposition apparatus including a tubular
container accommodating a substrate, source gas supply means for
supplying a source gas into the tubular container, a flat
ring-shaped antenna, disposed at a top of a ceiling surface of the
tubular container, for converting an interior of the tubular
container into a plasma by power supply, and power supply means for
supplying power to the antenna to generate a plasma of the source
gas within the tubular container, and adapted to produce a film on
a surface of the substrate by atoms and molecules excited and
activated by the plasma within the tubular container, further
comprising: a second antenna disposed around the antenna and
located outwardly of the ceiling surface, and second power supply
means for supplying the second antenna with an electric current
flowing in a direction opposite to a direction of an electric
current supplied to the antenna by the power supply means.
24. The plasma film deposition apparatus according to claim 23,
wherein the power supply means and the second power supply means
are an identical alternating current power source.
25. The plasma film deposition apparatus according to claim 23,
wherein connection between an alternating current power source as
the power supply means and the antenna, and connection between an
alternating current power source as the second power supply means
and the second antenna are in an identical direction, and phase
changing means is provided for rendering a phase of the alternating
current power source as the power supply means and a phase of the
alternating current power source as the second power supply means
opposite to each other.
26. The plasma film deposition apparatus according to claim 23,
wherein connection between an alternating current power source as
the power supply means and the antenna, and connection between an
alternating current power source as the second power supply means
and the second antenna are in opposite directions.
27. A plasma film deposition method which supplies power from above
a top of a ceiling surface of a tubular container to generate a
plasma within the tubular container, and produces a film on a
surface of a substrate by atoms and molecules excited and activated
there, comprising generating an electric current, which flows in a
direction opposite to a direction of an electric current supplied
for generation of the plasma, outwardly of the ceiling surface to
produce the film.
28. A plasma processing apparatus in which a ring-shaped antenna is
disposed at a top of a ceiling surface of a processing chamber,
power is supplied at a frequency of 10 MHz to 30 MHz to the antenna
by power supply means to generate a plasma within the processing
chamber, and processing is applied to a surface of a substrate by
atoms and molecules excited and activated there, wherein the
substrate is located in a region where the plasma has a high
density, but has a low electron temperature.
29. The plasma processing apparatus according to claim 28, wherein
the region where the plasma has the high density has an electron
density such that there are 1,010 electrons or more per cm3, and
the region where the plasma has the low electron temperature is a
region where the electron temperature is 1 electronvolt or
less.
30. A plasma processing apparatus in which a ring-shaped antenna is
disposed at a top of a ceiling surface of a processing chamber,
power is supplied to the antenna by power supply means to generate
a plasma within the processing chamber, and processing is applied
to a surface of a substrate by atoms and molecules excited and
activated there, wherein a high frequency power source with an
output of 2 kW to 15 kW and a frequency of 10 MHz to 30 MHz is
connected to the antenna, and a distance from a lower surface of
the antenna to the substrate is set at 190 mm or more in order to
locate the substrate in a region where an electron temperature is 1
electronvolt or less.
31. A plasma processing apparatus in which a ring-shaped antenna is
disposed at a top of a ceiling surface of a processing chamber,
power is supplied to the antenna by power supply means to generate
a plasma within the processing chamber, and processing is applied
to a surface of a substrate by atoms and molecules excited and
activated there, wherein a high frequency source with an output of
2 kW to 15 kW and a frequency of 10 MHz to 30 MHz is connected to
the antenna, and a distance from a lower surface of the antenna to
the substrate is set at 200 mm or more.
32. A plasma processing method which supplies power at a frequency
of 10 MHz to 30 MHz from above a top of a ceiling surface of a
tubular container to generate a plasma within the tubular
container, and applies processing to a surface of a substrate by
atoms and molecules excited and activated there, comprising
applying the processing to the substrate in a region where the
plasma has a high density, but has a low electron temperature.
Description
TECHNICAL FIELD
[0001] This invention relates to a plasma processing apparatus, and
a plasma processing method which generate a plasma to process a
substrate.
[0002] The present invention also relates to a plasma film
deposition apparatus, and a plasma film deposition method which
generate a plasma to perform film deposition on the surface of a
substrate by vapor phase deposition.
[0003] Currently, film deposition using a plasma CVD (chemical
vapor deposition) apparatus is known in the production of a
semiconductor. The plasma CVD apparatus is an apparatus in which a
material gas serving as a starting material for a film is
introduced into a film deposition chamber within a tubular
container, a high frequency is shot from a high frequency antenna
to convert the material gas into the state of a plasma, and active
excited atoms in the plasma promote a chemical reaction on the
surface of a substrate to carry out film deposition. In the plasma
CVD apparatus, the high frequency antenna in the shape of a flat
ring is disposed on the top of a ceiling surface opposed to the
substrate, and power is supplied to the high frequency antenna to
shoot a high frequency wave into the tubular container.
[0004] A plasma processing apparatus is disclosed, for example, in
Japanese Patent No. 3,172,340.
[0005] With an inductively coupled plasma CVD apparatus having the
flat ring-shaped high frequency antenna disposed on the top of the
ceiling surface opposed to the substrate, lines of magnetic force
(lines of magnetic flux density) of a coil on the outermost
periphery of the high frequency antenna were likely to pass through
the wall (tubular surface) of the tubular container. When the lines
of magnetic force (lines of magnetic flux density) passed through
the wall (tubular surface) of the tubular container, electrons and
ions moved along the lines of magnetic force, so that the electrons
and ions impinged on the wall of the tubular container, thus posing
the possibility of overheating or causing the occurrence of
particles by an etching action.
[0006] To suppress the impingement of the electrons and ions on the
wall surface, it has been conceived to render the diameter of the
flat ring-shaped high frequency antenna smaller than the diameter
of the tubular container so that the magnetic flux density in the
direction of the wall surface at the position of the wall of the
tubular container will become low. In this case, it has become
difficult to generate a uniform plasma over a wide range relative
to the size of the tubular container. This has caused the risk of
lowering the efficiency and decreasing the uniformity of plasma
within the tubular container.
[0007] The present invention has been accomplished in light of the
above-mentioned circumstances. An object of the present invention
is to provide a plasma processing apparatus and a plasma processing
method which can impart a low magnetic flux density in the
direction of the wall surface even when generating a uniform plasma
over a wide range within the tubular container.
[0008] With the plasma CVD apparatus (plasma processing apparatus),
moreover, the plasma density is so high that a voltage is applied
to the electrode on the surface of the semiconductor owing to a
potential difference of space, incurring the risk of destroying the
semiconductor device (device destruction due to a charging effect).
Currently, there is a demand for the development of a plasma
processing apparatus capable of suppressing device destruction due
to the charging effect.
[0009] The present invention has been accomplished in light of the
above-mentioned circumstances. Another object of the present
invention is to provide a plasma processing apparatus and a plasma
processing method which can suppress device destruction due to the
charging effect.
DISCLOSURE OF THE INVENTION
[0010] The plasma processing apparatus of the present invention is
a plasma processing apparatus in which a flat ring-shaped antenna
is disposed at a top of a ceiling surface of a processing chamber,
power is supplied by power supply means to generate a plasma within
the processing chamber, and processing is applied to a surface of a
substrate by atoms and molecules excited and activated there,
characterized in that
[0011] a second antenna located outwardly of the ceiling surface is
disposed around the antenna, and
[0012] second power supply means is provided for supplying the
second antenna with an electric current flowing in a direction
opposite to a direction of an electric current supplied to the
antenna.
[0013] As a result, the plasma processing apparatus can be
constituted such that lines of magnetic force heading in a
direction opposite to the direction of lines of magnetic force
appearing at the site of the antenna are generated at the site of
the second antenna, and even when a uniform plasma is generated
over a wide range within the tubular container, the magnetic flux
density in the direction of the wall surface can be rendered
low.
[0014] The plasma processing apparatus is also characterized in
that the power supply means and the second power supply means are
the same alternating current power source.
[0015] The plasma processing apparatus is also characterized in
that connection between an alternating current power source as the
power supply means and the antenna, and connection between an
alternating current power source as the second power supply means
and the second antenna are in the same direction, and phase
changing means is provided for rendering a phase of the alternating
current power source as the power supply means and a phase of the
alternating current power source as the second power supply means
opposite to each other.
[0016] The plasma processing apparatus is also characterized in
that connection between an alternating current power source as the
power supply means and the antenna, and connection between an
alternating current power source as the second power supply means
and the second antenna are in opposite directions.
[0017] The plasma processing apparatus is also characterized in
that the processing of the surface of the substrate is film
deposition for producing a film on the surface of the substrate by
the excited and activated atoms and molecules.
[0018] The plasma processing method of the present invention is a
plasma processing method which supplies power from above a top of a
ceiling surface of a processing chamber to generate a plasma within
the processing chamber, and applies processing to a surface of a
substrate by atoms and molecules excited and activated there,
characterized by
[0019] generating an electric current, which flows in a direction
opposite to a direction of an electric current supplied for
generation of the plasma, outwardly of the ceiling surface to apply
the processing.
[0020] As a result, the plasma processing method can be constituted
such that even when a uniform plasma is generated over a wide range
within the tubular container, the magnetic flux density in the
direction of the wall surface can be rendered low.
[0021] The plasma film deposition apparatus of the present
invention is a plasma film deposition apparatus including
[0022] a tubular container accommodating a substrate,
[0023] source gas supply means for supplying a source gas into the
tubular container,
[0024] a flat ring-shaped antenna, disposed at a top of a ceiling
surface of the tubular container, for converting an interior of the
tubular container into a plasma by power supply, and
[0025] power supply means for supplying power to the antenna to
generate a plasma of the source gas within the tubular container,
and
[0026] adapted to produce a film on a surface of the substrate by
atoms and molecules excited and activated by the plasma within the
tubular container,
[0027] characterized by:
[0028] a second antenna disposed around the antenna and located
outwardly of the ceiling surface, and
[0029] second power supply means for supplying the second antenna
with an electric current flowing in a direction opposite to a
direction of an electric current supplied to the antenna by the
power supply means.
[0030] As a result, the plasma film deposition apparatus can be
constituted such that lines of magnetic force heading in a
direction opposite to the direction of lines of magnetic force
appearing at the site of the antenna are generated at the site of
the second antenna, and even when a uniform plasma is generated
over a wide range within the tubular container, the magnetic flux
density in the direction of the wall surface can be rendered
low.
[0031] The plasma film deposition apparatus is also characterized
in that the power supply means and the second power supply means
are the same alternating current power source.
[0032] The plasma film deposition apparatus is also characterized
in that connection between an alternating current power source as
the power supply means and the antenna, and connection between an
alternating current power source as the second power supply means
and the second antenna are in the same direction, and phase
changing means is provided for rendering a phase of the alternating
current power source as the power supply means and a phase of the
alternating current power source as the second power supply means
opposite to each other.
[0033] The plasma film deposition apparatus is also characterized
in that connection between an alternating current power source as
the power supply means and the antenna, and connection between an
alternating current power source as the second power supply means
and the second antenna are in opposite directions.
[0034] The plasma film deposition method of the present invention
is a plasma film deposition method which supplies power from above
a top of a ceiling surface of a tubular container to generate a
plasma within the tubular container, and produces a film on a
surface of a substrate by atoms and molecules excited and activated
there, characterized by
[0035] generating an electric current, which flows in a direction
opposite to a direction of an electric current supplied for
generation of the plasma, outwardly of the ceiling surface to
produce the film.
[0036] As a result, the plasma film deposition method can be
constituted such that even when a uniform plasma is generated over
a wide range within the tubular container, the magnetic flux
density in the direction of the wall surface can be rendered
low.
[0037] The plasma processing apparatus of the present invention is
a plasma processing apparatus in which a ring-shaped antenna is
disposed at a top of a ceiling surface of a processing chamber,
power is supplied to the antenna by power supply means to generate
a plasma within the processing chamber, and processing is applied
to a surface of a substrate by atoms and molecules excited and
activated there, characterized in that
[0038] the substrate is located in a region where the plasma has a
high density, but has a low electron temperature.
[0039] As a result, the substrate can be located in a region where
the electron temperature is low even though the electron density is
high. Since the region has a low electron temperature, device
destruction of the substrate due to the charging effect can be
suppressed.
[0040] The plasma processing apparatus is also characterized in
that the region where the plasma has the high density has an
electron density such that there are 1,010 electrons or more per
cm.sup.3, and the region where the plasma has the low electron
temperature is a region where the electron temperature is 1
electronvolt or less.
[0041] Thus, device destruction of the substrate due to the
charging effect can be suppressed reliably.
[0042] The plasma processing apparatus of the present invention is
a plasma processing apparatus in which a ring-shaped antenna is
disposed at a top of a ceiling surface of a processing chamber,
power is supplied to the antenna by power supply means to generate
a plasma within the processing chamber, and processing is applied
to a surface of a substrate by atoms and molecules excited and
activated there, characterized in that
[0043] a high frequency power source with an output of 2 kW to 15
kW and a frequency of 10 MHz to 30 MHz is connected to the antenna,
and
[0044] a distance from a lower surface of the antenna to the
substrate is set at 190 mm or more in order to locate the substrate
in a region where an electron temperature is 1 electronvolt or
less.
[0045] Thus, the substrate can be located in a region where the
plasma has a low electron temperature even though the plasma has a
high density. Since the substrate is located in the region where
the electron temperature is low even though the electron density is
high, device destruction of the substrate due to the charging
effect can be suppressed.
[0046] The plasma processing apparatus of the present invention is
a plasma processing apparatus in which a ring-shaped antenna is
disposed at a top of a ceiling surface of a processing chamber,
power is supplied to the antenna by power supply means to generate
a plasma within the processing chamber, and processing is applied
to a surface of a substrate by atoms and molecules excited and
activated there, characterized in that
[0047] a high frequency source with an output of 2 kW to 15 kW and
a frequency of 10 MHz to 30 MHz is connected to the antenna,
and
[0048] a distance from a lower surface of the antenna to the
substrate is set at 200 mm or more.
[0049] Thus, the substrate can be located in a region where the
plasma has a low electron temperature even though the plasma has a
high density. Since the substrate is located in the region where
the electron temperature is low even though the electron density is
high, device destruction of the substrate due to the charging
effect can be suppressed reliably.
[0050] The plasma processing method of the present invention is a
plasma processing method which supplies power from above a top of a
ceiling surface of a tubular container to generate a plasma within
the tubular container, and applies processing to a surface of a
substrate by atoms and molecules excited and activated there,
characterized by
[0051] applying the processing to the substrate in a region where
the plasma has a high density, but has a low electron
temperature.
[0052] As a result, the substrate can be located in a region where
the electron temperature is low even though the electron density is
high. Since the region has a low electron temperature, device
destruction of the substrate due to the charging effect can be
suppressed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0053] FIG. 1 is a schematic side view of a plasma CVD apparatus
according to an embodiment of the present invention.
[0054] FIG. 2 is a plan view of the plasma CVD apparatus showing
the shape of an antenna.
[0055] FIG. 3 is a plan view of the plasma CVD apparatus showing
the shape of an antenna.
[0056] FIG. 4 is a plan view of the plasma CVD apparatus showing
the shape of an antenna.
[0057] FIG. 5 is a plan view of the plasma CVD apparatus showing
the shape of an antenna.
[0058] FIG. 6 is a schematic side view of a plasma CVD apparatus
according to another embodiment of the present invention.
[0059] FIG. 7 is a graph showing the relationship between the
distance from the lower surface of the antenna to a substrate and
an electron temperature.
BEST MODE FOR CARRYING OUT THE INVENTION
[0060] The present invention will now be described in more detail
with reference to the accompanying drawings.
[0061] An embodiment of the present invention is described
first.
[0062] The present invention is a plasma film deposition apparatus
in which a source gas (a material gas: e.g., SiH.sub.4) is supplied
into a film deposition chamber, and a plasma is generated to excite
and activate atoms and molecules, which form a film of silicon
oxide or silicon nitride on the surface of a substrate. According
to this apparatus, power is supplied from above the top of a
ceiling surface to a flat ring-shaped antenna to generate a plasma
within a tubular container under an inductively coupled system,
thereby forming the film of silicon oxide or silicon nitride on the
surface of the substrate.
[0063] At this time, an electric current flowing in a direction
opposite to the direction of a feed current for generating the
plasma is generated outwardly of the ceiling surface, whereby a
magnetic flux density in the direction of the wall surface at the
position of the wall is decreased to suppress impingement of
electrons and ions on the wall of the tubular container. As a
result, a uniform plasma can be generated over a wide range within
the tubular container with the use of the antenna having a diameter
fitting the diameter of the tubular container. At the same time,
the magnetic flux density in the direction of the wall surface can
be decreased to suppress overheating, and suppress the occurrence
of particles by an etching action.
[0064] Thus, it becomes possible to provide a plasma film
deposition apparatus which can impart a low magnetic flux density
in the direction of the wall surface even when generating a uniform
plasma over a wide range within the tubular container.
[0065] The present invention can also be applied to a plasma
processing apparatus in which a plasma is generated, and atoms and
molecules excited and activated thereby apply processing, such as
etching, to the surface of the substrate.
[0066] An embodiment in which the present invention is applied to a
plasma film deposition apparatus (plasma CVD apparatus) will be
described based on the drawings.
[0067] As shown in FIG. 1, a plasma CVD apparatus 1 is furnished
with a tubular container (container) 2 of a cylindrical shape and
made of aluminum, and a film deposition chamber 3 is formed within
the container 2. A circular ceiling plate 4 made of an insulating
material (for example, alumina: Al.sub.2O.sub.3) is provided at the
top of the container 2, and a wafer support base 5 is provided in
the film deposition chamber 3 at the center of the container 2. The
wafer support base 5 has a disk-shaped bearing portion 7 for
holding a semiconductor substrate 6, and the bearing portion 7 is
supported by a support shaft 8.
[0068] A high frequency antenna 11, for example, in the form of a
circular coil ring (flat ring) is placed on the ceiling plate 4,
and a high frequency power source 12 (alternating current power
source) is connected (power supply means) to the high frequency
antenna 11 via a matching instrument (not shown). Electric power is
supplied to the high frequency antenna, whereby an electromagnetic
wave is thrown into the film deposition chamber 3 of the container
2. The electromagnetic wave, thrown into the container 2, ionizes a
gas within the film deposition chamber 3 to generate a plasma.
[0069] The container 2 is provided with, for example, gas supply
nozzles 13 as source gas supply means for supplying a material gas,
such as silane (for example, SiH.sub.4). A source gas, which serves
as a material for film deposition (for example, Si) , is supplied
through the gas supply nozzles 13 into the film deposition chamber
3. The container 2 is also provided with auxiliary gas supply
nozzles (not shown), which are made of an insulator material (for
example, alumina: Al.sub.2O.sub.3), for supplying an inert gas
(rare gas) such as argon or helium, or an auxiliary gas such as
oxygen or hydrogen. The interior of the container 2 is maintained
at a predetermined pressure by a vacuum device 14.
[0070] The container 2 is also provided with a carry-in/carry-out
port for the substrate 6, although the carry-in/carry-out port is
not shown. Through this carry-in/carry-out port, the substrate 6 is
carried from a transport chamber (not shown) into the container 2,
and carried out of the container 2 to the transport chamber.
[0071] With the above-mentioned plasma CVD apparatus 1, the
substrate 6 is placed on the bearing portion 7 of the wafer support
base 5, and held (by, for example, an electrostatic chuck). A
predetermined flow rate of the source gas is supplied through the
gas supply nozzles 13 into the film deposition chamber 3, and also
a predetermined flow rate of the auxiliary gas is supplied through
the auxiliary gas supply nozzles into the film deposition chamber
3, with the interior of the film deposition chamber 3 being set at
a predetermined pressure suitable for the conditions for film
deposition. Then, electric power is supplied from the high
frequency power source 12 to the high frequency antenna 11 to
generate a high frequency wave.
[0072] By this procedure, the material gas within the film
deposition chamber 3 is electrically discharged to be partly turned
into the state of a plasma. This plasma impinges on other neutral
molecules in the material gas to ionize or excite the neutral
molecules further. The thus produced active particles are adsorbed
onto the surface of the substrate 6 to cause a chemical reaction
with good efficiency, whereby they are deposited to form a CVD
film.
[0073] With the inductively coupled plasma CVD apparatus 1 having
the flat ring-shaped high frequency antenna 11 disposed on the top
of the ceiling surface opposed to the substrate 6, lines of
magnetic force (lines of magnetic flux density) of a coil on the
outermost periphery of the high frequency antenna 11 were likely to
pass through the wall (tubular surface) of the container 2. When
the lines of magnetic force (lines of magnetic flux density) passed
through the wall (tubular surface) of the container 2, electrons
and ions moved along the lines of magnetic force, so that the
electrons and ions impinged on the wall of the container 2, thus
posing the possibility of overheating or causing the occurrence of
particles by an etching action.
[0074] In the present embodiment, therefore, a second antenna is
disposed around an outer part of the antenna on the ceiling
surface, whereby an electric current flowing in a direction
opposite to the direction of the electric current fed to the
antenna is supplied to the second antenna.
[0075] That is, as shown in FIG. 2, the high frequency antenna 11
is made up of an antenna 11a which is a portion of nearly the same
diameter as that of the ceiling surface, and a second antenna 11b
which is a portion located outwardly of the ceiling surface. An
electric current is supplied from the high frequency power source
12 to the site of the second antenna 11b in a state of connection
opposite to that for the site of the antenna 11a (i.e., second
power supply means). In detail, at the site of the second antenna
11b, the high frequency power source 12 is connected to the coil on
the grounded side at the site of the antenna 11a, so that the coil
at the site of the antenna 11a on a side, where the high frequency
power source 12 is connected, is brought into a grounded state.
[0076] Because of the above-described feature, lines of magnetic
force, F2, heading in a direction opposite to the direction of
lines of magnetic force, F1, appearing at the site of the antenna
11a are generated at the site of the second antenna 11b. The lines
F1 of magnetic force passing through the wall (tubular surface) of
the container 2 are merged with the lines F2 of magnetic force
heading in the opposite direction to decrease the lines of magnetic
force passing through the wall (tubular surface) of the container
2. Thus, the magnetic flux density in the direction of the wall
surface at the position of the wall of the container 2 is lowered.
This resolves the problem that the electrons and ions impinge on
the wall of the container 2, thereby causing overheating or causing
the occurrence of particles by an etching action.
[0077] Furthermore, the antenna 11a has nearly the same diameter as
the diameter of the ceiling surface. Thus, a uniform plasma can be
generated over a wide range relative to the size of the container,
there is no decrease in the efficiency, and the uniformity of the
plasma within the container 2 can be maintained. Hence, the plasma
CVD apparatus 1 is constituted such that even when a uniform plasma
is generated over a wide range within the container 2, the magnetic
flux density in the direction of the wall surface can be rendered
low, overheating can be avoided, and the occurrence of particles by
an etching action can be prevented.
[0078] Other embodiments of the plasma CVD apparatuses equipped
with antennas and power supply means according to other embodiments
will be described based on FIGS. 3 to 5. Constituent members other
than the antenna and power supply means are the same as those in
FIG. 1. Thus, explanations will be offered by reference to the plan
views of FIGS. 3 to 5 corresponding to FIG. 2, and descriptions of
the features of the same portions are omitted.
[0079] A second embodiment will be described based on FIG. 3.
[0080] In the embodiment shown in FIG. 3, a high frequency antenna
11, as an antenna, is the same as that in FIGS. 1 and 2 in terms of
its feature, and is in the form of a flat coil. A high frequency
power source 12 is connected to the site of the antenna 11a, while
a second high frequency power source 21 as second power supply
means is connected to the site of a second antenna 11b. An electric
current is supplied from the second high frequency power source 21
to the site of the second antenna 11b in a state of connection
opposite to that for the site of the antenna 11a. In detail, at the
site of the second antenna 11b, the high frequency power source 12
is connected to the coil on the grounded side at the site of the
antenna 11a, so that the coil at the site of the antenna 11a on a
side, where the high frequency power source 12 is connected, is
brought into a grounded state.
[0081] Because of the above-described feature, lines of magnetic
force, F2, heading in a direction opposite to the direction of
lines of magnetic force, F1, appearing at the site of the antenna
11a are generated at the site of the second antenna 11b, as in the
embodiment shown in FIG. 1. The lines F1 of magnetic force passing
through the wall (tubular surface) of the container 2 are merged
with the lines F2 of magnetic force heading in the opposite
direction to decrease the lines of magnetic force passing through
the wall (tubular surface) of the container 2. Thus, the magnetic
flux density in the direction of the wall surface at the position
of the wall of the container 2 is lowered. This resolves the
problem that the electrons and ions impinge on the wall of the
container 2, thereby causing overheating or causing the occurrence
of particles by an etching action.
[0082] Furthermore, the antenna 11a has nearly the same diameter as
the diameter of the ceiling surface. Thus, a uniform plasma can be
generated over a wide range relative to the size of the container,
there is no decrease in the efficiency, and the uniformity of the
plasma within the container 2 can be maintained. Hence, the plasma
CVD apparatus is constituted such that even when a uniform plasma
is generated over a wide range within the container 2, the magnetic
flux density in the direction of the wall surface can be rendered
low, overheating can be avoided, and the occurrence of particles by
an etching action can be prevented.
[0083] A third embodiment will be described based on FIG. 4.
[0084] In the embodiment shown in FIG. 4, a flat coil-shaped high
frequency antenna 22, as an antenna having nearly the same diameter
as the diameter of a ceiling plate 4, is disposed. A second antenna
23, having a different feature from that of the high frequency
antenna 22, is disposed outside of the high frequency antenna 22,
namely, outwardly of the ceiling surface. A high frequency power
source 12 is connected to the high frequency antenna 22, while a
second high frequency power source 24 as second power supply means
is connected to the second antenna 23. The high frequency antenna
22 and the second high frequency power source 24 are connected to
the high frequency power source 12 and the second high frequency
power source 24 in the same direction. The second high frequency
power source 24 is connected to the second antenna 23 via a phase
shifter 25 as phase changing means.
[0085] An electric current of a phase opposite to that of an
electric current fed from the high frequency power source 12 to the
high frequency antenna 22 is supplied from the second high
frequency power source 24 to the second antenna 23 via the phase
shifter 25. Because of this feature, lines of magnetic force
heading in a direction opposite to the direction of lines of
magnetic force appearing at the site of the high frequency antenna
22 are generated at the site of the second antenna 23, as in the
embodiment shown in FIG. 1. The lines of magnetic force passing
through the wall (tubular surface) of the container 2 are merged
with the lines of magnetic force heading in the opposite direction
to decrease the lines of magnetic force passing through the wall
(tubular surface) of the container 2. Thus, the magnetic flux
density in the direction of the wall surface at the position of the
wall of the container 2 is lowered. This resolves the problem that
the electrons and ions impinge on the wall of the container 2,
thereby causing overheating or causing the occurrence of particles
by an etching action.
[0086] Furthermore, the high frequency antenna 22 has nearly the
same diameter as the diameter of the ceiling surface. Thus, a
uniform plasma can be generated over a wide range relative to the
size of the container 2, there is no decrease in the efficiency,
and the uniformity of the plasma within the container 2 can be
maintained. Hence, the plasma CVD apparatus is constituted such
that even when a uniform plasma is generated over a wide range
within the container 2, the magnetic flux density in the direction
of the wall surface can be rendered low, overheating can be
avoided, and the occurrence of particles by an etching action can
be prevented.
[0087] A fourth embodiment will be described based on FIG. 5.
[0088] In the embodiment shown in FIG. 5, a high frequency antenna
31, which has nearly the same diameter as the diameter of a ceiling
plate 4, is composed of antennas 31a, 31b, 31c and 31d each in the
form of a concentric ring. A ring-shaped second antenna 32 is
disposed outside of the high frequency antenna 31, namely,
outwardly of the ceiling surface. A high frequency power source 12
is connected in parallel to the antennas 31a, 31b, 31c, 31d, and
the second antenna 32 is connected to the high frequency power
source 12 in a state of connection opposite to that for the ring
antenna 31. That is, the second antenna 32 is connected to the high
frequency power source 12 in a state opposite to the state of
connection of the antenna 31 to the high frequency power source 12,
namely, such that the connected side and the grounded side for the
second antenna 32 are opposite to those for the antenna 31.
[0089] Because of this feature, lines of magnetic force heading in
a direction opposite to the direction of lines of magnetic force
appearing at the site of the antenna 31 are generated at the site
of the second antenna 32, as in the embodiment shown in FIG. 1. The
lines of magnetic force passing through the wall (tubular surface)
of the container 2 are merged with the lines of magnetic force
heading in the opposite direction to decrease the lines of magnetic
force passing through the wall (tubular surface) of the container
2. Thus, the magnetic flux density in the direction of the wall
surface at the position of the wall of the container 2 is lowered.
This resolves the problem that the electrons and ions impinge on
the wall of the container 2, thereby causing overheating or causing
the occurrence of particles by an etching action.
[0090] Furthermore, the antenna 31 has nearly the same diameter as
the diameter of the ceiling surface. Thus, a uniform plasma can be
generated over a wide range relative to the size of the container
2, there is no decrease in the efficiency, and the uniformity of
the plasma within the container 2 can be maintained. Hence, the
plasma CVD apparatus is constituted such that even when a uniform
plasma is generated over a wide range within the container 2, the
magnetic flux density in the direction of the wall surface can be
rendered low, overheating can be avoided, and the occurrence of
particles by an etching action can be prevented.
[0091] Other embodiments will be described.
[0092] The present invention is a plasma film deposition apparatus
in which a source gas (a material gas: e.g., SiH.sub.4) is supplied
into a film deposition chamber, and a plasma is generated to excite
and activate atoms and molecules, which form a film of silicon
oxide or silicon nitride on the surface of a substrate. According
to this apparatus, power is supplied from above the top of a
ceiling surface to a ring-shaped antenna to generate a plasma
within a tubular container under an inductively coupled system,
thereby forming a film of silicon oxide or silicon nitride on the
surface of the substrate.
[0093] The substrate is located in a region where the plasma has a
low electron temperature even when the plasma has a high density.
The region where the plasma is at a high density has an electron
density such that there are 1,010 electrons or more per cm.sup.3.
The region where the plasma is at a low electron temperature is a
region where the electron temperature is 1 electronvolt or
less.
[0094] Furthermore, a high frequency power source of 10 MHz to 30
MHz is connected to an antenna, and the distance from the lower
surface of the antenna to a substrate is set at 190 mm or more in
order to locate the substrate in a region where the electron
temperature is 1 electronvolt or less.
[0095] Alternatively, a high frequency power source of 10 MHz to 30
MHz is connected to an antenna, and the distance from the lower
surface of the antenna to a substrate is set at 200 mm or more.
[0096] Thus, the substrate is located in a region where the
electron temperature is low even though the electron density is
high. Since the region has a low electron temperature, device
destruction due to the charging effect can be suppressed.
[0097] As the present invention, there can be applied a plasma
processing apparatus in which a plasma is generated to excite and
activate atoms and molecules, which apply processing, such as
etching or ashing, to the surface of a substrate.
[0098] An embodiment in which the present invention is applied to a
plasma film deposition apparatus (plasma CVD apparatus) will be
described based on a drawing.
[0099] As shown in FIG. 6, a plasma CVD apparatus 81 is furnished
with a tubular container (container) 82 of a cylindrical shape and
made of aluminum, and a film deposition chamber 3 (for example,
diameter 250 mm to 500 mm) is formed within the container 82. A
circular ceiling plate 84 made of an insulator material (for
example, alumina: Al.sub.2O.sub.3, thickness 30 mm) is provided at
the top of the container 82, and a wafer support base 85 is
provided in the film deposition chamber 83 at the center of the
container 82. The wafer support base 85 has a disk-shaped bearing
portion 87 for holding a semiconductor substrate 86, and the
substrate 86 is held on the bearing portion 7, for example, by
electrostatic chuck means 88.
[0100] A high frequency antenna 91, as an antenna, for example, in
the form of a circular coil ring (flat ring), is placed on the
ceiling plate 84, and a high frequency power source 92 (alternating
current power source) is connected (high frequency source) to the
high frequency antenna 91 via a matching instrument (not shown).
Electric power is supplied to the high frequency antenna 91,
whereby an electromagnetic wave is thrown into the film deposition
chamber 83 of the container 82. The electromagnetic wave, thrown
into the container 82, ionizes a gas within the film deposition
chamber 83 to generate a plasma.
[0101] The high frequency source with an output of 2 kW to 15 kW
(e.g., 5 kW) and a frequency of 10 MHz to 30 MHz (e.g., 13.56 MHz)
is connected to the high frequency antenna 91.
[0102] The container 82 is provided with, for example, gas supply
nozzles 13 for supplying a material gas, such as silane (for
example, SiH.sub.4). A source gas, which serves as a material for
film deposition (for example, SiO.sub.2), is supplied through the
gas supply nozzles 13 into the film deposition chamber 3. The
container 2 is also provided with auxiliary gas supply nozzles (not
shown), which are made of an insulator material (for example,
alumina: Al.sub.2O.sub.3), for supplying an inert gas (rare gas)
such as argon or helium, or an auxiliary gas such as oxygen or
hydrogen. The interior of the container 82 is maintained at a
predetermined pressure (for example, a vacuum atmosphere on the
order of 0.1 Pa to 10 Pa) by a vacuum device 94.
[0103] The container 82 is provided with a carry-in/carry-out port
for the substrate 86, although the carry-in/carry-out port is not
shown. Through this carry-in/carry-out port, the substrate 86 is
carried from a transport chamber (not shown) into the container 82,
and carried out of the container 82 to the transport chamber.
[0104] With the above-mentioned plasma CVD apparatus 81, the
substrate 86 is placed on the bearing portion 87 of the wafer
support base 85, and held (by, for example, electrostatic chuck
means 88). A predetermined flow rate of the source gas is supplied
through the gas supply nozzles 93 into the film deposition chamber
83, and also a predetermined flow rate of the auxiliary gas is
supplied through the auxiliary gas supply nozzles into the film
deposition chamber 83, with the interior of the film deposition
chamber 83 being set at a predetermined pressure suitable for the
conditions for film deposition. Then, electric power is supplied
from the high frequency power source 92 to the high frequency
antenna 91 to generate a high frequency electromagnetic wave.
[0105] By this procedure, the material gas within the film
deposition chamber 83 is electrically discharged to be partly
turned into the state of a plasma. This plasma impinges on other
neutral molecules in the material gas to ionize or excite the
neutral molecules further. The thus produced active particles are
adsorbed onto the surface of the substrate 86 to cause a chemical
reaction with good efficiency, whereby they are deposited.
[0106] The substrate 86 held on the bearing portion 87 of the wafer
support base 85 is located in a region where the plasma has a low
electron temperature even though the plasma has a high density.
That is, the position of the substrate 86 (the height of the
bearing portion 87) is set such that the distance H from the lower
surface of the high frequency antenna 91 to the substrate 86 is 190
mm to 250 mm (preferably of the order of 200 mm). To adjust the
position of the substrate 86, the bearing portion 87 may be
rendered free to ascend and descend.
[0107] By setting the position of the substrate 86 such that the
distance H from the lower surface of the high frequency antenna 91
to the substrate 86 is 190 mm to 250 mm, a high density plasma
region is produced which has an electron density of 1,010 electrons
or more per cm.sup.3 and has an electron temperature of 1
electronvolt (eV) or less.
[0108] By locating the substrate 86 in the region where the
electron temperature is low even though the electron density is
high, device destruction of the substrate 86 due to the charging
effect can be suppressed, since this region has a low electron
temperature.
[0109] The relationship between the distance H from the lower
surface of the high frequency antenna 91 to the substrate 86 and
the electron temperature is explained based on FIG. 2.
[0110] As shown in FIG. 2, the electron temperature is several eV
when the distance H is in a range of 0 mm to less than 190 mm. When
the distance H is 190 mm, the electron temperature is 1 eV. At the
distance H of 190 mm or more, the electron temperature is 1 eV or
less. By setting the distance H from the lower surface of the high
frequency antenna 91 to the substrate 6 to be 190 mm to 250 mm,
therefore, device destruction of the substrate 6 due to the
charging effect can be suppressed, because of this region having a
low electron temperature.
[0111] Even if the distance H exceeds 300 mm, device destruction of
the substrate 86 due to the charging effect can be suppressed,
because of this region having a low electron temperature. However,
the greater the distance H, the lower the film deposition rate
becomes, making the film deposition time longer. In order to
suppress device destruction of the substrate 86 due to the charging
effect while maintaining the film deposition rate, therefore, one
will note that the distance H from the lower surface of the high
frequency antenna 91 to the substrate 6 should desirably be set at
190 mm to 250 mm.
[0112] Even if the distance H exceeds 200 mm, the electron
temperature sufficiently lowers without lowering of the film
deposition rate, so that device destruction of the substrate 86 due
to the charging effect can be suppressed reliably. A study
involving the distance H set at 200 mm confirmed that although
1,000 films were deposited at a gate oxide film-electrode area
ratio of 2,000,000:1, none of the devices of the substrate 86 were
destroyed by the charging effect.
[0113] By setting the position of the substrate 86 such that the
distance H from the lower surface of the high frequency antenna 91
to the substrate 6 is 190 mm to 250 mm, therefore, a high density
plasma region having an electron density of 1,010 electrons or more
per cm.sup.3 becomes a region having an electron temperature of 1
electronvolt (eV) or less. As noted here, the substrate 6 is
located in the region at a low electron temperature despite a high
electron density. Since this region has a low electron temperature,
device destruction of the substrate 6 due to the charging effect
can be suppressed.
INDUSTRIAL APPLICABILITY
[0114] As described above, there is disclosed a plasma film
deposition method in which power is supplied from above a ceiling
surface of a tubular container to generate a plasma within the
tubular container, and a film is prepared on the surface of a
substrate by atoms and molecules excited and activated there. In
this method, the film is produced, with an electric current in a
direction opposite to the direction of a feed current for plasma
generation being generated outwardly of the ceiling surface. Thus,
it becomes possible to provide a plasma film deposition method
which can impart a low magnetic flux density in the direction of
the wall surface even when generating a uniform plasma over a wide
range within the tubular container.
[0115] Moreover, there is disclosed a plasma processing method in
which power is supplied from above a ceiling surface of a tubular
container to generate a plasma within the tubular container, and
processing is applied to the surface of a substrate by atoms and
molecules excited and activated there. In this method, processing
is applied to the substrate in a region where the plasma has a low
electron temperature even though the plasma has a high density.
Thus, the substrate can be located in the region at a low electron
temperature despite a high electron density. Thus, device
destruction of the substrate by a charging effect can be
suppressed, since the region is at a low electron temperature.
* * * * *