U.S. patent application number 12/379052 was filed with the patent office on 2009-09-03 for electrode for plasma processing apparatus, plasma processing apparatus, plasma processing method and storage medium.
This patent application is currently assigned to TOKYO ELECTRON LIMITED. Invention is credited to Shinji Himori, Masanobu Honda.
Application Number | 20090221151 12/379052 |
Document ID | / |
Family ID | 41013518 |
Filed Date | 2009-09-03 |
United States Patent
Application |
20090221151 |
Kind Code |
A1 |
Honda; Masanobu ; et
al. |
September 3, 2009 |
Electrode for plasma processing apparatus, plasma processing
apparatus, plasma processing method and storage medium
Abstract
The present invention provides an upper electrode used in an
etching apparatus and the etching apparatus including the upper
electrode, both of which can properly reduce intensity of electric
field of plasma around a central portion of a substrate to be
processed, thus enhancing in-plane uniformity of a plasma process.
In this apparatus, a recess, serving as a space for allowing a
dielectric to be injected therein, is provided around a central
portion of the upper electrode. A dielectric supply passage
configured for supplying the dielectric into the space and a
dielectric discharge passage configured for discharging the
dielectric from the space are connected with the space,
respectively. With such configuration, the dielectric can be
controllably supplied into the recess, such that in-plane
distribution of the intensity of the electric field can be
uniformed, corresponding to in-plane distribution of the intensity
of the electric field of the plasma generated under various process
conditions, such as a kind of each wafer that will be etched, each
processing gas that will be used, and the like.
Inventors: |
Honda; Masanobu;
(Nirasaki-shi, JP) ; Himori; Shinji;
(Nirasaki-shi, JP) |
Correspondence
Address: |
SMITH, GAMBRELL & RUSSELL
1130 CONNECTICUT AVENUE, N.W., SUITE 1130
WASHINGTON
DC
20036
US
|
Assignee: |
TOKYO ELECTRON LIMITED
Tokyo-To
JP
|
Family ID: |
41013518 |
Appl. No.: |
12/379052 |
Filed: |
February 11, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61071556 |
May 6, 2008 |
|
|
|
Current U.S.
Class: |
438/729 ;
156/345.27; 156/345.43; 257/E21.485; 438/711 |
Current CPC
Class: |
H01J 37/3244 20130101;
H01J 37/32091 20130101; H01J 37/32009 20130101; H01J 37/32541
20130101; H01J 37/32449 20130101 |
Class at
Publication: |
438/729 ;
438/711; 156/345.43; 156/345.27; 257/E21.485 |
International
Class: |
H01L 21/465 20060101
H01L021/465; C23F 1/08 20060101 C23F001/08 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 29, 2008 |
JP |
2008-050745 |
Claims
1. An electrode for use in a plasma process, wherein the electrode
is provided to be opposed to a lower electrode on which a substrate
is placed in a processing space, wherein high frequency power is
supplied to a space between the electrode and the lower electrode,
so as to generate plasma therein and perform the plasma process to
the substrate, and wherein the electrode comprises: an electrode
plate provided to be opposed to the lower electrode; a support
member provided opposite to the lower electrode across the
electrode plate, configured for supporting the electrode plate, and
having a dielectric injection space formed therein such that a
dielectric used for controlling intensity of an electric field in
the processing space can be injected into the dielectric injection
space; a dielectric supply source connected with the dielectric
injection space of the support member via a dielectric supply
passage and configured for supplying the dielectric into the
dielectric injection space; and a dielectric discharge passage
connected with the dielectric injection space of the support member
and configured for discharging the dielectric from the dielectric
injection space.
2. The electrode for use in the plasma process according to claim
1, wherein the dielectric injection space of the support member is
provided along a face on the side of the electrode plate of the
support member.
3. The electrode for use in the plasma process according to claim
1, wherein a member having a gas diffusion space formed therein is
provided, the gas diffusion space being connected with a processing
gas supply source configured for supplying a processing gas to the
substrate, and wherein a plurality of gas discharge ports are
provided on the electrode plate, each of the gas discharge ports
being in communication with the gas diffusion space and configured
for injecting the processing gas into the processing space, like a
shower.
4. The electrode for use in the plasma process according to claim
3, wherein the member having the gas diffusion space formed therein
is also used as the electrode plate or used as the support
member.
5. The electrode for use in the plasma process according to claim
3, wherein the member having the gas diffusion space formed therein
is provided between the electrode plate and the support member.
6. The electrode for use in the plasma process according to claim
5, wherein the member having the gas diffusion space formed therein
is formed from a dielectric having a relative permittivity within a
range of 1 to 10.
7. The electrode for use in the plasma process according to claim
1, wherein a gas supply member is provided to be projected downward
from a central portion of the electrode plate, the gas supply
member having a dome-like shape and a plurality of gas discharge
apertures formed therein, each of the gas discharge apertures being
configured for injecting the processing gas into the processing
space.
8. The electrode for use in the plasma process according to claim
1, wherein a temperature control mechanism adapted for controlling
the temperature of the support member is provided to the support
member.
9. An electrode for use in a plasma process, wherein the electrode
is provided to be opposed to an upper electrode in a processing
space, wherein high frequency power is supplied to a space between
the electrode and the upper electrode, so as to generate plasma
therein and perform the plasma process to a substrate placed on one
face of the electrode, and wherein the electrode comprises: an
electrode member provided to be opposed to the upper electrode,
wherein at least one of a first high frequency power source for
generating the plasma and a second high frequency power source for
introducing ions present in the plasma is connected with the
electrode member; a dielectric-injection-space-constituting member
having a dielectric injection space formed therein such that a
dielectric used for controlling intensity of an electric field in
the processing space can be injected into the dielectric injection
space; a dielectric supply source connected with the dielectric
injection space of the dielectric-injection-space-constituting
member via a dielectric supply passage and configured for supplying
the dielectric into the dielectric injection space; and a
dielectric discharge passage connected with the dielectric
injection space and configured for discharging the dielectric from
the dielectric injection space.
10. The electrode for use in the plasma process according to claim
1 or 9, wherein the dielectric injection space is provided in a
position corresponding to a central portion of the substrate.
11. The electrode for use in the plasma process according to claim
1 or 9, wherein the dielectric discharge passage is connected with
the dielectric supply source, such that the dielectric can be
circulated between the dielectric injection space and the
dielectric supply source.
12. The electrode for use in the plasma process according to claim
1 or 9, further comprising a storage unit adapted for storing
therein data correlating a kind of each process with an injection
amount of the dielectric into the dielectric injection space, and a
means adapted for reading the injection amount of the dielectric
corresponding to the kind of each selected process from the storage
unit then controlling the injection amount of the dielectric.
13. A plasma processing apparatus including an upper electrode, a
table constituting a lower electrode, and a processing vessel
having a processing space containing the upper electrode and the
lower electrode therein, the plasma processing apparatus
comprising: a first high frequency power source connected with the
lower electrode and used for generating plasma; a gas supply
passage configured for supplying a processing gas into the
processing vessel; and a vacuum exhaust means adapted for
evacuating the interior of the processing vessel, wherein the upper
electrode comprises: an electrode plate provided to be opposed to
the lower electrode; a support member provided opposite to the
lower electrode across the electrode plate, configured for
supporting the electrode plate, and having a dielectric injection
space formed therein such that a dielectric used for controlling
intensity of an electric field in the processing space can be
injected into the dielectric injection space; a dielectric supply
source connected with the dielectric injection space of the support
member via a dielectric supply passage and configured for supplying
the dielectric into the dielectric injection space; and a
dielectric discharge passage connected with the dielectric
injection space of the support member and configured for
discharging the dielectric from the dielectric injection space.
14. A plasma processing apparatus including an upper electrode, a
table constituting a lower electrode, and a processing vessel
having a processing space containing the upper electrode and lower
electrode therein, the plasma processing apparatus comprising: a
first high frequency power source connected with the lower
electrode and used for generating plasma; a gas supply passage
configured for supplying a processing gas into the processing
vessel; and a vacuum exhaust means adapted for evacuating the
interior of the processing vessel, wherein the lower electrode
comprises: an electrode member provided to be opposed to the upper
electrode; a dielectric-injection-space-constituting member having
a dielectric injection space formed therein such that a dielectric
used for controlling intensity of an electric field in the
processing space can be injected into the dielectric injection
space; a dielectric supply source connected with the dielectric
injection space of the dielectric-injection-space-constituting
member via a dielectric supply passage and configured for supplying
the dielectric into the dielectric injection space; and a
dielectric discharge passage connected with the dielectric
injection space and configured for discharging the dielectric from
the dielectric injection space.
15. A plasma processing apparatus including an upper electrode, a
table constituting a lower electrode, and a processing vessel
having a processing space containing the upper electrode and the
lower electrode therein, the plasma processing apparatus
comprising: a first high frequency power source connected with
either one of the upper electrode and lower electrode and used for
generating plasma; a second high frequency power source connected
with the lower electrode and used for introducing ions present in
the plasma; a gas supply passage configured for supplying a
processing gas into the processing vessel; and a vacuum exhaust
means adapted for evacuating the interior of the processing vessel
into a vacuum state, wherein the upper electrode comprises: an
electrode plate provided to be opposed to the lower electrode; a
support member provided opposite to the lower electrode across the
electrode plate, configured for supporting the electrode plate, and
having a dielectric injection space formed therein such that a
dielectric used for controlling intensity of an electric field in
the processing space can be injected into the dielectric injection
space; a dielectric supply source connected with the dielectric
injection space of the support member via a dielectric supply
passage and configured for supplying the dielectric into the
dielectric injection space; and a dielectric discharge passage
connected with the dielectric injection space of the support member
and configured for discharging the dielectric from the dielectric
injection space.
16. A plasma processing apparatus including an upper electrode, a
table constituting a lower electrode, and a processing vessel
having a processing space containing the upper electrode and the
lower electrode therein, the plasma processing apparatus
comprising: a first high frequency power source connected with
either one of the upper electrode and the lower electrode and used
for generating plasma; a second high frequency power source
connected with the lower electrode and used for introducing ions
present in the plasma; a gas supply passage configured for
supplying a processing gas into the processing vessel; and a vacuum
exhaust means adapted for evacuating the interior of the processing
vessel, wherein the lower electrode comprises: an electrode member
provided to be opposed to the upper electrode; a
dielectric-injection-space-constituting member having a dielectric
injection space formed therein such that a dielectric used for
controlling intensity of an electric field in the processing space
can be injected into the dielectric injection space; a dielectric
supply source connected with the dielectric injection space of the
dielectric-injection-space-constituting member via a dielectric
supply passage and configured for supplying the dielectric into the
dielectric injection space; and a dielectric discharge passage
connected with the dielectric injection space and configured for
discharging the dielectric from the dielectric injection space.
17. A plasma processing method using a plasma processing apparatus
including an upper electrode, a table constituting a lower
electrode, a processing vessel configured for containing the upper
electrode and the lower electrode therein, and a first high
frequency power source connected with the lower electrode and used
for generating plasma, wherein the upper electrode and the lower
electrode are arranged to be opposed to each other, and wherein the
plasma processing method comprises the steps of: supplying a
dielectric into a dielectric injection space formed in the upper
electrode; placing a substrate on the table; supplying a processing
gas into the processing vessel; and changing the processing gas
into the plasma between the upper electrode and the lower
electrode, so as to perform a plasma process to the substrate with
the plasma, wherein the step of supplying the dielectric is
performed for controlling a supply amount of the dielectric, such
that in-plane uniformity of intensity of an electric field of the
plasma can be enhanced, as compared with the case in which the
dielectric is not supplied into the dielectric injection space.
18. A plasma processing method using a plasma processing apparatus
including an upper electrode, a table constituting a lower
electrode, a processing vessel configured for containing the upper
electrode and the lower electrode therein, a first high frequency
power source connected with either one of the upper electrode and
the lower electrode and used for generating plasma, and a second
high frequency power source connected with the lower electrode and
used for introducing ions present in the plasma, wherein the upper
electrode and the lower electrode are arranged to be opposed to
each other, and wherein the plasma processing method comprises the
steps of: supplying a dielectric into a dielectric injection space
formed in the upper electrode; placing a substrate on the table;
supplying a processing gas into the processing vessel; and changing
the processing gas into the plasma between the upper electrode and
the lower electrode, so as to provide a plasma process to the
substrate with the plasma, wherein the step of supplying the
dielectric is performed for controlling a supply amount of the
dielectric, such that in-plane uniformity of intensity of an
electric field of the plasma can be enhanced, as compared with the
case in which the dielectric is not supplied into the dielectric
injection space.
19. A plasma processing method using a plasma processing apparatus
including an upper electrode, a table constituting a lower
electrode, a processing vessel configured for containing the upper
electrode and the lower electrode therein, and a first high
frequency power source connected with the lower electrode and used
for generating plasma, wherein the upper electrode and the lower
electrode are arranged to be opposed to each other, and wherein the
plasma processing method comprises the steps of: supplying a
dielectric into a dielectric injection space formed in the lower
electrode; placing a substrate on the table; supplying a processing
gas into the processing vessel; and changing the processing gas
into the plasma between the upper electrode and the lower
electrode, so as to perform a plasma process to the substrate with
the plasma, wherein the step of supplying the dielectric is
performed for controlling a supply amount of the dielectric, such
that in-plane uniformity of intensity of an electric field of the
plasma can be enhanced, as compared with the case in which the
dielectric is not supplied into the dielectric injection space.
20. A plasma processing method using a plasma processing apparatus
including an upper electrode, a table constituting a lower
electrode, a processing vessel configured for containing the upper
electrode and the lower electrode therein, a first high frequency
power source connected with either one of the upper electrode and
the lower electrode and used for generating plasma, and a second
high frequency power source connected with the lower electrode and
used for introducing ions present in the plasma, wherein the upper
electrode and the lower electrode are arranged to be opposed to
each other, and wherein the plasma processing method comprises the
steps of: supplying a dielectric into a dielectric injection space
formed in the lower electrode; placing a substrate on the table;
supplying a processing gas into the processing vessel; and changing
the processing gas into the plasma between the upper electrode and
the lower electrode, so as to perform a plasma process to the
substrate with the plasma, wherein the step of supplying the
dielectric is performed for controlling a supply amount of the
dielectric, such that in-plane uniformity of intensity of an
electric field of the plasma can be enhanced, as compared with the
case in which the dielectric is not supplied into the dielectric
injection space.
21. The plasma processing method according to any one of claims 17
to 20, further comprising the steps of: reading data correlating a
kind of each process with an injection amount of the dielectric
into the dielectric injection space, prior to the step of supplying
the dielectric; and controlling the injection amount of the
dielectric into the dielectric injection space.
22. A storage medium for storing therein a computer program for
driving a computer to execute a plasma processing method, wherein
the plasma processing method uses a plasma processing apparatus
including an upper electrode, a table constituting a lower
electrode, a processing vessel configured for containing the upper
electrode and the lower electrode therein, and a first high
frequency power source connected with the lower electrode and used
for generating plasma, wherein the upper electrode and the lower
electrode are arranged to be opposed to each other, and wherein the
plasma processing method comprises the steps of: supplying a
dielectric into a dielectric injection space formed in the upper
electrode; placing a substrate on the table; supplying a processing
gas into the processing vessel; and changing the processing gas
into the plasma between the upper electrode and the lower
electrode, so as to perform a plasma process to the substrate with
the plasma, wherein the step of supplying the dielectric is
performed for controlling a supply amount of the dielectric, such
that in-plane uniformity of intensity of an electric field of the
plasma can be enhanced, as compared with the case in which the
dielectric is not supplied into the dielectric injection space.
23. A storage medium for storing therein a computer program for
driving a computer to execute a plasma processing method, wherein
the plasma processing method uses a plasma processing apparatus
including an upper electrode, a table constituting a lower
electrode, a processing vessel configured for storing the upper
electrode and the lower electrode therein, a first high frequency
power source connected with either one of the upper electrode and
the lower electrode and used for generating plasma, and a second
high frequency power source connected with the lower electrode and
used for introducing ions present in the plasma, wherein the upper
electrode and the lower electrode are arranged to be opposed to
each other, and wherein the plasma processing method comprises the
steps of: supplying a dielectric into a dielectric injection space
formed in the upper electrode; placing a substrate on the table;
supplying a processing gas into the processing vessel; and changing
the processing gas into the plasma between the upper electrode and
the lower electrode, so as to perform a plasma process to the
substrate with the plasma, wherein the step of supplying the
dielectric is performed for controlling a supply amount of the
dielectric, such that in-plane uniformity of intensity of an
electric field of the plasma can be enhanced, as compared with the
case in which the dielectric is not supplied into the dielectric
injection space.
24. A storage medium for storing therein a computer program for
driving a computer to execute a plasma processing method, wherein
the plasma processing method uses a plasma processing apparatus
including an upper electrode, a table constituting a lower
electrode, a processing vessel configured for containing the upper
electrode and the lower electrode therein, and a first high
frequency power source connected with the lower electrode and used
for generating plasma, wherein the upper electrode and lower
electrode are arranged to be opposed to each other, and wherein the
plasma processing method comprises the steps of: supplying a
dielectric into a dielectric injection space formed in the lower
electrode; placing a substrate on the table; supplying a processing
gas into the processing vessel; and changing the processing gas
into the plasma between the upper electrode and the lower
electrode, so as to perform a plasma process to the substrate with
the plasma, wherein the step of supplying the dielectric is
performed for controlling a supply amount of the dielectric, such
that in-plane uniformity of intensity of an electric field of the
plasma can be enhanced, as compared with the case in which the
dielectric is not supplied into the dielectric injection space.
25. A storage medium for storing therein a computer program for
driving a computer to execute a plasma processing method, wherein
the plasma processing method uses a plasma processing apparatus
including an upper electrode, a table constituting a lower
electrode, a processing vessel configured for containing the upper
electrode and the lower electrode therein, a first high frequency
power source connected with either one of the upper electrode and
the lower electrode and used for generating plasma, and a second
high frequency power source connected with the lower electrode and
used for introducing ions present in the plasma, wherein the upper
electrode and the lower electrode are arranged to be opposed to
each other, and wherein the plasma processing method comprises the
steps of: supplying a dielectric into a dielectric injection space
formed in the lower electrode; placing a substrate on the table;
supplying a processing gas into the processing vessel; and changing
the processing gas into the plasma between the upper electrode and
the lower electrode, so as to perform a plasma process to the
substrate with the plasma, wherein the step of supplying the
dielectric is performed for controlling a supply amount of the
dielectric, such that in-plane uniformity of intensity of an
electric field of the plasma can be enhanced, as compared with the
case in which the dielectric is not supplied into the dielectric
injection space.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on the prior Japanese Patent
Application No. 2008-50745 filed on Feb. 29, 2008 and U.S.
Provisional Patent Application No. 61/71556 filed on May 6, 2008,
the entire contents of which are incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an upper electrode, a table
(or lower electrode), a plasma processing apparatus including at
least one of the upper electrode and table, a plasma processing
method and a storage medium, each used for processing a substrate
to be processed, such as a semiconductor wafer or the like, to
which a plasma process is provided.
[0004] 2. Background Art
[0005] In a step for manufacturing semiconductor devices, for
example, a dry etching process, an ashing process and the like has
been known, as the plasma process for processing the substrate by
changing a processing gas into plasma. In an etching apparatus for
performing the dry etching process, for example, a pair of parallel
and flat electrodes are vertically arranged to be opposed to each
other. By application of high frequency electric power to a space
between the two electrodes, the processing gas introduced into the
space can be changed into the plasma. As a result, the substrate to
be processed, such as the semiconductor wafer (hereinafter referred
to as "the wafer") or the like, which is placed on the lower
electrode, can be subjected to the etching process. For example, as
the etching process, a process for forming recesses in a film
formed on the wafer, by using a resist pattern, as a mask, provided
on the film to be etched, has been known.
[0006] In recent years, a "lower energy and higher density"
process, requiring lower ion energy in the plasma and higher
electron density, has been widely used in the plasma process. For
instance, in the case of etching a silicon film or any other
organic film, properly high frequency electric power is generally
applied to the electrode provided on a lower side, in order to
generate higher density plasma and suppress introduction or capture
of ions into the wafer.
[0007] In some cases, for the generation of such lower energy and
higher density plasma, an extremely high frequency, e.g., 100 MHz,
of the high frequency electric power should be required, as
compared with the frequency (e.g., approximately several ten MHz)
that has been employed so far. However, such an extremely high
frequency of the electric power applied to the apparatus may tend
to considerably increase intensity of an electric field around a
central portion of a surface of the electrode, i.e., a region
corresponding to a central portion of the wafer, while relatively
decreasing the intensity of the electric field around the periphery
of the wafer. Therefore, as shown in FIG. 16, the etching process
is progressed at a higher rate around the central portion of the
wafer, while exhibiting a significantly lower etching rate around
the periphery of the wafer.
[0008] To address such problems, Patent Documents 1 and 2 disclose
improved etching apparatuses, respectively. Each of these
apparatuses is intended for enhancing in-plane uniformity of the
plasma process, by embedding a dielectric in a region around the
central portion of the upper electrode, such that distribution of
the electric field can made uniform by the dielectric. In fact,
such an etching apparatus is suitable for providing the plasma
process to each wafer having the same layered structure under the
same conditions. In some cases, however, the etching process should
be provided to different wafers, such as those having different
films to be etched and/or different kinds of resist pattern films
formed thereon.
[0009] Additionally, although having the same layered structure,
each wafer sometimes has the resist pattern formed thereon with a
different shape and/or is sometimes designed to have the recesses
each formed in the film while having a different aspect ratio
(i.e., a ratio of a depth of the recess relative to a diameter of
an opening thereof).
[0010] In such a case, the process conditions, such as a kind
and/or pressure of each processing gas used, each value of the high
frequency electric power and the like, should be controlled,
corresponding to a kind or the like of each wafer. Therefore, the
state or condition of the plasma should also be changed with such
control of the process conditions. Thus, for enhancing the in-plane
uniformity of the plasma process, it is necessary to control the
distribution of the electric field, corresponding to the process
conditions. However, in the etching apparatus having the dielectric
provided in the upper electrode as disclosed in the above Patent
Documents, the dielectric should be exchanged with another one,
such as by disassembling the apparatus, in order to control the
distribution of the electric field. This makes it substantially
difficult to optionally control the distribution of the electric
field, corresponding to the process conditions.
[0011] Patent Document 3 describes a technique for controlling a
relative permittivity, by providing a control part formed from a
dielectric material, between a chamber body and a first electrode.
More specifically, the control part has a tank-like structure
provided therein, such that a material that can optionally control
the relative permittivity can be supplied into the tank-like
structure. This configuration is only aimed to control the
equivalent relative permittivity, by controlling a degree of
electrical connection between the first electrode and the grounded
chamber body. Accordingly, this technique cannot solve the above
problems in nature.
[0012] Patent Document 1: JP2000-323456A (Paragraph [0049], FIG.
4)
[0013] Patent Document 2: JP2005-228973A (Paragraphs [0030] to
[0033], FIG. 1)
[0014] Patent Document 3: JP2007-48748A (Paragraph [0038], FIGS. 3
to 5)
SUMMARY OF THE INVENTION
[0015] The present invention was made in light of the above
circumstances, and therefore it is an object of this invention to
provide a new upper electrode and/or table (or lower electrode),
which is used for the plasma processing apparatus and adapted for
providing the plasma process to the substrate or wafer with higher
in-plane uniformity, by enhancing the in-plane uniformity of the
intensity of the electric field of the plasma, with a simple
structure, corresponding to the process conditions. Another object
of this invention is to provide an improved plasma processing
apparatus including at least one of the upper electrode and table
related to this invention, a plasma processing method using this
plasma processing apparatus, and a storage medium for storing this
plasma processing method therein.
[0016] The present invention is an electrode for use in a plasma
process, wherein the electrode is provided to be opposed to a lower
electrode on which a substrate is placed in a processing space,
wherein high frequency power is supplied to a space between the
electrode and the lower electrode, so as to generate plasma therein
and perform the plasma process to the substrate, and wherein the
electrode comprises: an electrode plate provided to be opposed to
the lower electrode; a support member provided opposite to the
lower electrode across the electrode plate, configured for
supporting the electrode plate, and having a dielectric injection
space formed therein such that a dielectric used for controlling
intensity of an electric field in the processing space can be
injected into the dielectric injection space; a dielectric supply
source connected with the dielectric injection space of the support
member via a dielectric supply passage and configured for supplying
the dielectric into the dielectric injection space; and a
dielectric discharge passage connected with the dielectric
injection space of the support member and configured for
discharging the dielectric from the dielectric injection space.
[0017] In the electrode for use in the plasma process according to
the present invention, the dielectric injection space of the
support member is provided along a face on the side of the
electrode plate of the support member.
[0018] In the electrode for use in the plasma process according to
the present invention, a member having a gas diffusion space formed
therein is provided, the gas diffusion space being connected with a
processing gas supply source configured for supplying a processing
gas to the substrate, wherein a plurality of gas discharge ports
are provided on the electrode plate, each of the gas discharge
ports being in communication with the gas diffusion space and
configured for injecting the processing gas into the processing
space, like a shower.
[0019] In the electrode for use in the plasma process according to
the present invention, the member having the gas diffusion space
formed therein is also used as the electrode plate or used as the
support member.
[0020] In the electrode for use in the plasma process according to
the present invention, the member having the gas diffusion space
formed therein is provided between the electrode plate and the
support member.
[0021] In the electrode for use in the plasma process according to
the present invention, the member having the gas diffusion space
formed therein is formed from a dielectric having a relative
permittivity within a range of 1 to 10.
[0022] In the electrode for use in the plasma process according to
the present invention, a gas supply member is provided to be
projected downward from a central portion of the electrode plate,
the gas supply member having a dome-like shape and a plurality of
gas discharge apertures formed therein, each of the gas discharge
apertures being configured for injecting the processing gas into
the processing space.
[0023] In the electrode for use in the plasma process according to
the present invention, a temperature control mechanism adapted for
controlling the temperature of the support member is provided to
the support member.
[0024] Alternatively, the present invention is an electrode for use
in a plasma process, wherein the electrode is provided to be
opposed to an upper electrode in a processing space, wherein high
frequency power is supplied to a space between the electrode and
the upper electrode, so as to generate plasma therein and perform
the plasma process to a substrate placed on one face of the
electrode, and wherein the electrode comprises: an electrode member
provided to be opposed to the upper electrode, a
dielectric-injection-space-constituting member having a dielectric
injection space formed therein such that a dielectric used for
controlling intensity of an electric field in the processing space
can be injected into the dielectric injection space; a dielectric
supply source connected with the dielectric injection space of the
dielectric-injection-space-constituting member via a dielectric
supply passage and configured for supplying the dielectric into the
dielectric injection space; and a dielectric discharge passage
connected with the dielectric injection space and configured for
discharging the dielectric from the dielectric injection space.
[0025] In the electrode for use in the plasma process according to
the present invention, the dielectric injection space is provided
in a position corresponding to a central portion of the
substrate.
[0026] In the electrode for use in the plasma process according to
the present invention, the dielectric discharge passage is
connected with the dielectric supply source, such that the
dielectric can be circulated between the dielectric injection space
and the dielectric supply source.
[0027] The electrode for use in the plasma process according to the
present invention, further comprises a storage unit adapted for
storing therein data correlating a kind of each process with an
injection amount of the dielectric into the dielectric injection
space, and a means adapted for reading the injection amount of the
dielectric corresponding to the kind of each selected process from
the storage unit then controlling the injection amount of the
dielectric.
[0028] Alternatively, the present invention is a plasma processing
apparatus including an upper electrode, a table constituting a
lower electrode, and a processing vessel having a processing space
containing the upper electrode and the lower electrode therein, the
plasma processing apparatus comprising: a first high frequency
power source connected with the lower electrode and used for
generating plasma; a gas supply passage configured for supplying a
processing gas into the processing vessel; and a vacuum exhaust
means adapted for evacuating the interior of the processing vessel,
wherein the upper electrode comprises: an electrode plate provided
to be opposed to the lower electrode; a support member provided
opposite to the lower electrode across the electrode plate,
configured for supporting the electrode plate, and having a
dielectric injection space formed therein such that a dielectric
used for controlling intensity of an electric field in the
processing space can be injected into the dielectric injection
space; a dielectric supply source connected with the dielectric
injection space of the support member via a dielectric supply
passage and configured for supplying the dielectric into the
dielectric injection space; and a dielectric discharge passage
connected with the dielectric injection space of the support member
and configured for discharging the dielectric from the dielectric
injection space.
[0029] Alternatively, the present invention is a plasma processing
apparatus including an upper electrode, a table constituting a
lower electrode, and a processing vessel having a processing space
containing the upper electrode and the lower electrode therein, the
plasma processing apparatus comprising: a first high frequency
power source connected with the lower electrode and used for
generating plasma; a gas supply passage configured for supplying a
processing gas into the processing vessel; and a vacuum exhaust
means adapted for evacuating the interior of the processing vessel,
wherein the lower electrode comprises: an electrode member provided
to be opposed to the upper electrode, wherein at least one of the
first high frequency power source for generating the plasma and a
second high frequency power source for introducing ions present in
the plasma is connected with the electrode member; a
dielectric-injection-space-constituting member having a dielectric
injection space formed therein such that a dielectric used for
controlling intensity of an electric field in the processing space
can be injected into the dielectric injection space; a dielectric
supply source connected with the dielectric injection space of the
dielectric-injection-space-constituting member via a dielectric
supply passage and configured for supplying the dielectric into the
dielectric injection space; and a dielectric discharge passage
connected with the dielectric injection space and configured for
discharging the dielectric from the dielectric injection space.
[0030] Alternatively, the present invention is a plasma processing
apparatus including an upper electrode, a table constituting a
lower electrode, and a processing vessel having a processing space
containing the upper electrode and the lower electrode therein, the
plasma processing apparatus comprising: a first high frequency
power source connected with either one of the upper electrode and
lower electrode and used for generating plasma; a second high
frequency power source connected with the lower electrode and used
for introducing ions present in the plasma; a gas supply passage
configured for supplying a processing gas into the processing
vessel; and a vacuum exhaust means adapted for evacuating the
interior of the processing vessel into a vacuum state, wherein the
upper electrode comprises: an electrode plate provided to be
opposed to the lower electrode; a support member provided opposite
to the lower electrode across the electrode plate, configured for
supporting the electrode plate, and having a dielectric injection
space formed therein such that a dielectric used for controlling
intensity of an electric field in the processing space can be
injected into the dielectric injection space; a dielectric supply
source connected with the dielectric injection space of the support
member via a dielectric supply passage and configured for supplying
the dielectric into the dielectric injection space; and a
dielectric discharge passage connected with the dielectric
injection space of the support member and configured for
discharging the dielectric from the dielectric injection space.
[0031] Alternatively, the present invention is a plasma processing
apparatus including an upper electrode, a table constituting a
lower electrode, and a processing vessel having a processing space
containing the upper electrode and the lower electrode therein, the
plasma processing apparatus comprising: a first high frequency
power source connected with either one of the upper electrode and
the lower electrode and used for generating plasma; a second high
frequency power source connected with the lower electrode and used
for introducing ions present in the plasma; a gas supply passage
configured for supplying a processing gas into the processing
vessel; and a vacuum exhaust means adapted for evacuating the
interior of the processing vessel, wherein the lower electrode
comprises: an electrode member provided to be opposed to the upper
electrode, a dielectric-injection-space-constituting member having
a dielectric injection space formed therein such that a dielectric
used for controlling intensity of an electric field in the
processing space can be injected into the dielectric injection
space; a dielectric supply source connected with the dielectric
injection space of the dielectric-injection-space-constituting
member via a dielectric supply passage and configured for supplying
the dielectric into the dielectric injection space; and a
dielectric discharge passage connected with the dielectric
injection space and configured for discharging the dielectric from
the dielectric injection space.
[0032] Alternatively, the present invention is a plasma processing
method using a plasma processing apparatus including an upper
electrode, a table constituting a lower electrode, a processing
vessel configured for containing the upper electrode and the lower
electrode therein, and a first high frequency power source
connected with the lower electrode and used for generating plasma,
wherein the upper electrode and the lower electrode are arranged to
be opposed to each other, and wherein the plasma processing method
comprises the steps of: supplying a dielectric into a dielectric
injection space formed in the upper electrode; placing a substrate
on the table; supplying a processing gas into the processing
vessel; and changing the processing gas into the plasma between the
upper electrode and the lower electrode, so as to perform a plasma
process to the substrate with the plasma, wherein the step of
supplying the dielectric is performed for controlling a supply
amount of the dielectric, such that in-plane uniformity of
intensity of an electric field of the plasma can be enhanced, as
compared with the case in which the dielectric is not supplied into
the dielectric injection space.
[0033] Alternatively, the present invention is a plasma processing
method using a plasma processing apparatus including an upper
electrode, a table constituting a lower electrode, a processing
vessel configured for containing the upper electrode and the lower
electrode therein, a first high frequency power source connected
with either one of the upper electrode and the lower electrode and
used for generating plasma, and a second high frequency power
source connected with the lower electrode and used for introducing
ions present in the plasma, wherein the upper electrode and the
lower electrode are arranged to be opposed to each other, and
wherein the plasma processing method comprises the steps of:
supplying a dielectric into a dielectric injection space formed in
the upper electrode; placing a substrate on the table; supplying a
processing gas into the processing vessel; and changing the
processing gas into the plasma between the upper electrode and the
lower electrode, so as to provide a plasma process to the substrate
with the plasma, wherein the step of supplying the dielectric is
performed for controlling a supply amount of the dielectric, such
that in-plane uniformity of intensity of an electric field of the
plasma can be enhanced, as compared with the case in which the
dielectric is not supplied into the dielectric injection space.
[0034] Alternatively, the present invention is a plasma processing
method using a plasma processing apparatus including an upper
electrode, a table constituting a lower electrode, a processing
vessel configured for containing the upper electrode and the lower
electrode therein, and a first high frequency power source
connected with the lower electrode and used for generating plasma,
wherein the upper electrode and the lower electrode are arranged to
be opposed to each other, and wherein the plasma processing method
comprises the steps of: supplying a dielectric into a dielectric
injection space formed in the lower electrode; placing a substrate
on the table; supplying a processing gas into the processing
vessel; and changing the processing gas into the plasma between the
upper electrode and the lower electrode, so as to perform a plasma
process to the substrate with the plasma, wherein the step of
supplying the dielectric is performed for controlling a supply
amount of the dielectric, such that in-plane uniformity of
intensity of an electric field of the plasma can be enhanced, as
compared with the case in which the dielectric is not supplied into
the dielectric injection space.
[0035] Alternatively, the present invention is a plasma processing
method using a plasma processing apparatus including an upper
electrode, a table constituting a lower electrode, a processing
vessel configured for containing the upper electrode and the lower
electrode therein, a first high frequency power source connected
with either one of the upper electrode and the lower electrode and
used for generating plasma, and a second high frequency power
source connected with the lower electrode and used for introducing
ions present in the plasma, wherein the upper electrode and the
lower electrode are arranged to be opposed to each other, and
wherein the plasma processing method comprises the steps of:
supplying a dielectric into a dielectric injection space formed in
the lower electrode; placing a substrate on the table; supplying a
processing gas into the processing vessel; and changing the
processing gas into the plasma between the upper electrode and the
lower electrode, so as to perform a plasma process to the substrate
with the plasma, wherein the step of supplying the dielectric is
performed for controlling a supply amount of the dielectric, such
that in-plane uniformity of intensity of an electric field of the
plasma can be enhanced, as compared with the case in which the
dielectric is not supplied into the dielectric injection space.
[0036] The plasma processing method according to the present
invention further comprises the steps of: reading data correlating
a kind of each process with an injection amount of the dielectric
into the dielectric injection space, prior to the step of supplying
the dielectric; then controlling the injection amount of the
dielectric into the dielectric injection space.
[0037] Alternatively, the present invention is a storage medium for
storing therein a computer program for driving a computer to
execute a plasma processing method, wherein the plasma processing
method uses a plasma processing apparatus including an upper
electrode, a table constituting a lower electrode, a processing
vessel configured for containing the upper electrode and the lower
electrode therein, and a first high frequency power source
connected with the lower electrode and used for generating plasma,
wherein the upper electrode and the lower electrode are arranged to
be opposed to each other, and wherein the plasma processing method
comprises the steps of: supplying a dielectric into a dielectric
injection space formed in the upper electrode; placing a substrate
on the table; supplying a processing gas into the processing
vessel; and changing the processing gas into the plasma between the
upper electrode and the lower electrode, so as to perform a plasma
process to the substrate with the plasma, wherein the step of
supplying the dielectric is performed for controlling a supply
amount of the dielectric, such that in-plane uniformity of
intensity of an electric field of the plasma can be enhanced, as
compared with the case in which the dielectric is not supplied into
the dielectric injection space.
[0038] Alternatively, the present invention is a storage medium for
storing therein a computer program for driving a computer to
execute a plasma processing method, wherein the plasma processing
method uses a plasma processing apparatus including an upper
electrode, a table constituting a lower electrode, a processing
vessel configured for storing the upper electrode and the lower
electrode therein, a first high frequency power source connected
with either one of the upper electrode and the lower electrode and
used for generating plasma, and a second high frequency power
source connected with the lower electrode and used for introducing
ions present in the plasma, wherein the upper electrode and the
lower electrode are arranged to be opposed to each other, and
wherein the plasma processing method comprises the steps of:
supplying a dielectric into a dielectric injection space formed in
the upper electrode; placing a substrate on the table; supplying a
processing gas into the processing vessel; and changing the
processing gas into the plasma between the upper electrode and the
lower electrode, so as to perform a plasma process to the substrate
with the plasma, wherein the step of supplying the dielectric is
performed for controlling a supply amount of the dielectric, such
that in-plane uniformity of intensity of an electric field of the
plasma can be enhanced, as compared with the case in which the
dielectric is not supplied into the dielectric injection space.
[0039] Alternatively, the present invention is a storage medium for
storing therein a computer program for driving a computer to
execute a plasma processing method, wherein the plasma processing
method uses a plasma processing apparatus including an upper
electrode, a table constituting a lower electrode, a processing
vessel configured for containing the upper electrode and lower
electrode therein, and a first high frequency power source
connected with the lower electrode and used for generating plasma,
wherein the upper electrode and the lower electrode are arranged to
be opposed to each other, and wherein the plasma processing method
comprises the steps of: supplying a dielectric into a dielectric
injection space formed in the lower electrode; placing a substrate
on the table; supplying a processing gas into the processing
vessel; and changing the processing gas into the plasma between the
upper electrode and the lower electrode, so as to perform a plasma
process to the substrate with the plasma, wherein the step of
supplying the dielectric is performed for controlling a supply
amount of the dielectric, such that in-plane uniformity of
intensity of an electric field of the plasma can be enhanced, as
compared with the case in which the dielectric is not supplied into
the dielectric injection space.
[0040] Alternatively, the present invention is a storage medium for
storing therein a computer program for driving a computer to
execute a plasma processing method, wherein the plasma processing
method uses a plasma processing apparatus including an upper
electrode, a table constituting a lower electrode, a processing
vessel configured for containing the upper electrode and the lower
electrode therein, a first high frequency power source connected
with either one of the upper electrode and the lower electrode and
used for generating plasma, and a second high frequency power
source connected with the lower electrode and used for introducing
ions present in the plasma, wherein the upper electrode and the
lower electrode are arranged to be opposed to each other, and
wherein the plasma processing method comprises the steps of:
supplying a dielectric into a dielectric injection space formed in
the lower electrode; placing a substrate on the table; supplying a
processing gas into the processing vessel; and changing the
processing gas into the plasma between the upper electrode and the
lower electrode, so as to perform a plasma process to the substrate
with the plasma, wherein the step of supplying the dielectric is
performed for controlling a supply amount of the dielectric, such
that in-plane uniformity of intensity of an electric field of the
plasma can be enhanced, as compared with the case in which the
dielectric is not supplied into the dielectric injection space.
[0041] According to the present invention, with the provision of
the dielectric injection space configured for allowing the
dielectric to be injected therein, to the upper electrode or table
constituting the lower electrode, each used in the plasma
processing apparatus, as well as with the provision of the
dielectric supply passage and dielectric discharge passage, each
being in communication with the dielectric injection space, the
dielectric can be controllably supplied into the dielectric
injection space. Accordingly, with such control of the amount of
the dielectric injected into the dielectric injection space, a
capacitor component due to the dielectric injection space can be
optionally changed. Thus, in-plane distribution of the intensity of
the electric field of the plasma can be controlled with ease,
thereby to provide the plasma process with significantly higher
in-plane uniformity, corresponding to various process
conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 is a longitudinal side cross section showing one
example of an etching apparatus including an upper electrode of the
present invention.
[0043] FIG. 2 is a longitudinal side cross section showing one
example of the upper electrode.
[0044] FIG. 3 is a plan view of the upper electrode when it is seen
from below.
[0045] FIG. 4 is a schematic diagram showing one example of a
control unit related to the etching apparatus.
[0046] FIG. 5 is a schematic diagram showing one exemplary
operation of the etching apparatus.
[0047] FIG. 6 is a schematic diagram showing another example of the
operation of the etching apparatus.
[0048] FIG. 7 is a longitudinal side cross section showing another
example of the upper electrode of the present invention.
[0049] FIG. 8 is a longitudinal side cross section showing still
another example of the upper electrode of the present
invention.
[0050] FIG. 9 is a longitudinal side cross section showing one
example in which a recess is provided in a table, rather than
provided in the upper electrode.
[0051] FIG. 10 is a longitudinal side cross section showing another
example of the etching apparatus.
[0052] FIGS. 11(a) through 11(e) illustrate profiles, respectively
showing results related to examples of the present invention.
[0053] FIGS. 12(a) through 12(f) illustrate other profiles,
respectively showing results related to examples of the present
invention.
[0054] FIGS. 13(a) through 13(e) illustrate other profiles,
respectively showing results related to examples of the present
invention.
[0055] FIGS. 14(a) through 14(d) illustrate other profiles,
respectively showing results related to examples of the present
invention.
[0056] FIGS. 15(a) through 15(d) illustrate other profiles,
respectively showing results related to examples of the present
invention.
[0057] FIG. 16 is a schematic diagram showing a state of plasma in
one conventional etching apparatus.
DETAILED DESCRIPTION OF THE INVENTION
[0058] Hereinafter, one embodiment will be described with reference
to FIG. 1, wherein one exemplary upper electrode related to the
present invention is applied to an etching apparatus. FIG. 1 shows
one example of the etching apparatus of an RIE (Reactive Ion
Etching) type, which is adapted for providing an etching process to
a semiconductor wafer (hereinafter referred to as a "wafer") W
having, for example, a 300 mm diameter. This etching apparatus
includes a processing vessel 21 (e.g., a vacuum chamber having a
space hermetically sealed therein) formed of an electrically
conductive material, for example, aluminum; a table 30 provided on
a central portion of a bottom face of the processing vessel 21; and
an upper electrode 50 located above the table 30 while being
opposed to the table 30.
[0059] An exhaust port 22 is provided through the bottom face of
the processing vessel 21, and is communicated with a vacuum exhaust
system 23 (or vacuum exhaust means) including a vacuum pump or the
like means, via an exhaust pipe 24 provided with a pressure control
means (not shown). A transfer port 25 for the wafer W is provided
in a wall face of the processing vessel, such that the port 25 can
be optically opened and closed by a gate valve 26. In a site (i.e.,
an inner wall and a top wall of the processing vessel 21) outside a
processing space 1 defined between the upper electrode 50 and the
table 30 in the processing vessel 21, a covering member 21a is
provided for suppressing attachment, to the apparatus, of unwanted
by-products that will be generated, such as by etching. It is noted
that the processing vessel 21 is grounded.
[0060] The table 30 is composed of a lower electrode 31, which
serves as an electrode member, and a support member 32 adapted for
supporting the lower electrode 31 from below. The table 30 is
provided on the bottom face of the processing vessel 21, via an
insulating member 33. In addition, the table 30 is covered, around
its side face, by a ring member 40. Further, a covering member 41
is provided, around the ring member 40, for suppressing the
attachment of the by-products that will be generated, such as by
etching.
[0061] To an upper portion of the table 30, an electro-static chuck
34 having a plurality of through-holes (not shown) formed therein
is provided. In this manner, when some voltage is applied to an
electrode film 34a formed in the electro-static chuck 34 from a
high-voltage direct-current power source 35, the wafer W will be
electro-statically chucked on the table 30.
[0062] In the table 30, a temperature control flow passage 37 is
formed. This temperature control flow passage 37 is configured for
allowing a predetermined temperature control medium to flow
therethrough. Thus, the wafer W can be controlled to a desired
temperature by the temperature control medium flowed through the
temperature control flow passage 37. Additionally, a gas flow
passage 38, configured for supplying a heat conducting gas, such as
a He (helium) gas or the like, used as a back-side gas, is provided
in the table 30. The gas flow passage 38 is opened at several
points in a top face of the table 30. The openings of the gas flow
passage 38 are respectively communicated with the through-holes
formed in the electro-static chuck 34. As such, the back-side gas
can be supplied to a rear face or back-side face of the wafer
W.
[0063] To the lower electrode 31, a first high-frequency power
source 6a adapted for supplying first high-frequency power of, for
example, 100 MHz, and a second high-frequency power source 6b
adapted for supplying second high-frequency power of, for example,
3.2 MHz, which is lower than the frequency of the first
high-frequency power source 6a, are connected, via matching
circuits 7a, 7b, respectively. The first high-frequency power
supplied from the first high-frequency power source 6a is used for
changing a processing gas, as will described later, into plasma,
while the second high-frequency power supplied from the second
high-frequency power source 6b is used for applying bias power to
the wafer W so as to introduce ions present in the plasma into a
surface of the wafer.
[0064] A focus ring 39 is located on an outer periphery of the
lower electrode 31, such that the ring 39 surrounds the
electro-static chuck 34. Thus, when the plasma is generated, the
plasma can be focused on the wafer W placed on the table 30, via
the focus ring 39.
[0065] Between the covering member 41 located in a lower position
of the processing vessel 21 and the inner wall of the processing
vessel 21 (or covering member 21a), a baffle plate 28, as a gas
distributor for controlling the flow of the processing gas, is
provided.
[0066] Next, one embodiment of the upper electrode 50 of this
invention will be described. The upper electrode 50 includes an
electrode plate 54, a support member 51 adapted for supporting the
electrode plate 54, and a gas diffusion member 54a located between
the electrode plate 54 and the support member 51. In this case, the
support member 51, gas diffusion member 54a and electrode plate 54
are layered in this order from the top. The support member 51 is
provided to have a bottom-face diameter (i.e., a diameter of a
bottom face thereof) slightly larger, for example, by approximately
10 mm, than the diameter of the wafer W, and is formed from
electrically conductive aluminum. The upper electrode 50 is
circumferentially supported by the top wall of the processing
vessel 21 via an insulating member 52.
[0067] As shown in FIG. 2, the gas diffusion member 54a is formed
to have the same diameter as the bottom-face diameter of the
support member 51, and has a gas supply port 55 provided in a
central position of a top face thereof. In the gas diffusion member
54a, a gas diffusion passage 56, i.e., a horizontally extending
space for diffusing a gas, is provided to be in communication with
the gas supply port 55. The gas diffusion member 54a is formed
from, for example, a metal having higher electrical resistance, or
from a dielectric, such as a PTFE (polytetrafluoroethylene) resin
or the like, having a relative permittivity within a range of from
1 to 10.
[0068] The electrode plate 54 is formed from, for example, silicon,
and has a plurality of gas discharge ports 53 formed in its bottom
face. Each of the gas discharge ports 53 is configured for
supplying the processing gas into the processing space 1, like a
shower, and is in communication with the gas diffusion passage 56.
The electrode plate 54 is formed to have the same diameter as the
bottom-face diameter of the support member 51, and has a thickness
t1 of, for example, 5 mm, and resistivity of 0.5 .OMEGA.m at
25.degree. C.
[0069] As shown in FIGS. 2 and 3, a recess 57, having a diameter R
of, for example, 160 mm and a depth t2 of, for example, 5 mm, is
formed in a central portion of the bottom face of the support
member 51. The recess 57 serves as a dielectric injection space for
storing the dielectric therein, as will be described below, and is
located in a position corresponding to a central portion of the
wafer W. While not shown in FIGS. 1 and 2, a sealing member 58 is
provided at the bottom face of the support member 51 around the
recess 57, wherein the sealing member 58 is fit in a ring-like
groove. With such configuration, when the electrode plate 54 and
support member 51 are firmly contacted together, by pressure, due
to a fixing means, such as by using bolts or the like (not shown),
the recess 57 will be kept in a hermetically sealed state.
[0070] Additionally, a gas supply pipe 59 is provided in the
central portion of the support member 51. The gas supply pipe 59
constitutes a gas flow passage vertically extending through the
support member 51. The gas supply pipe 59 extends, at its lower end
portion, through the recess 57, and is airtightly connected with
the gas supply port 55 on the top face of the gas diffusion member
54a. Accordingly, the recess 57 is airtightly separated from the
gas supply pipe 59 and processing space 1.
[0071] A top end of the gas supply pipe 59 is connected with a gas
supply pipe 60 constituting a gas supply passage provided in the
top face of the support member 51. To an upstream end of the gas
supply pipe 60, a processing gas supply source 83 storing therein
the processing gas used for etching is connected, via a gas supply
system 100 including a valve 81 and a flow-rate controller 82.
While not shown in the drawings, a plurality of processing gas
supply sources are connected with the processing gas supply source
83, via, for example, a plurality of branch passages, valves and/or
flow-rate controllers. As such, suitable processing gases can be
switched, corresponding to a kind of each wafer W that will be
subjected to the process.
[0072] Furthermore, a dielectric supply passage 61 and a dielectric
discharge passage 62, both connected with a top face (or face
opposed to the gas diffusion member 54a) of the recess 57, are
provided in the support member 51, such that the two passages 61,
62 can be in communication with the recess 57, respectively. The
dielectric supply passage 61 is opened at a level of the top face
of the recess 57, while the dielectric discharge passage 62 is
opened in the recess 57, in a position adjacent to the gas
diffusion member 54a. To an upstream end of the dielectric supply
passage 61, a dielectric supply source 65 is connected, via a valve
63 and a liquid feeding means 64, such as a rotary pump or the
like. In the dielectric supply source 65, a dielectric is stored,
which is a liquid having a relative permittivity of approximately
1.9, such as a fluorine-containing inert liquid (C.sub.6F.sub.14).
The dielectric supply passage 61 is also opened in the dielectric
supply source 65 in a position adjacent to a bottom face
thereof.
[0073] To a portion of the dielectric supply passage 61 extending
downstream (or on the side of the support member 51) relative to
the valve 63, one end of a discharge gas supply passage 91 is
connected. The discharge gas supply passage 91 is configured for
supplying, for example, a nitrogen gas, into the recess 57, via the
dielectric supply passage 61, so as to discharge the dielectric
stored in the recess 57 to the outside, via the dielectric
discharge passage 62, by pressure of the nitrogen gas. Meanwhile,
the other end of the discharge gas supply passage 91 is connected
with a discharge gas supply source 94 storing, for example, the
nitrogen gas, therein, via a valve 92 and a flow-rate controller
93. To a downstream end (or one end opposite to the recess 57) of
the dielectric discharge passage 62, the dielectric supply source
65 is connected. Thus, the dielectric stored in the recess 57 can
be returned into the dielectric supply source 65, via the
dielectric discharge passage 62. To a top face of the dielectric
supply source 65, a gas exhaust pipe 66, configured for discharging
a gas present in the dielectric supply source 65 to the outside, is
connected. When the dielectric and/or nitrogen gas is supplied into
the recess 57, the nitrogen gas that has been supplied into the
dielectric supply source 65 via the dielectric discharge passage 62
is discharged, by opening the valve 67 provided to the gas exhaust
pipe 66. These valves 63, 67, 92, liquid feeding means 64 and
flow-rate controller 93 constitute, together, a dielectric supply
system 101.
[0074] Above the recess 57 in the support member 51, a temperature
control flow passage 71, which serves as a temperature control
mechanism, having a snake-like shape, extends in a horizontal
direction, as shown in FIG. 3. To both ends of the temperature
control flow passage 71, a temperature-control-medium supply
passage 72 and a temperature-control-medium discharge passage 73,
both extending through the top face of the support member 51, are
connected, respectively. To an upstream end of the
temperature-control-medium supply passage 72, as shown in FIG. 1, a
temperature-control-medium supply source 78 is connected, via a
temperature control mechanism 75, such as a heater, a chiller and
the like, a valve 76, and a liquid feeding means 77 including a
flow rate controller. Thus, the temperature of the electrode plate
54 can be controlled within a predetermined range of, for example,
60.degree. C. to 200.degree. C., with a temperature control medium
controlled within such a predetermined temperature range of, for
example, 60.degree. C. to 200.degree. C. and flowed through the
support member 51. The temperature-control-medium supply source 78
is also connected with a downstream end (or discharge side end) of
the temperature-control-medium discharge passage 73. Thus, the
temperature control medium can be circulated by the liquid feeding
means 77. In this case, the temperature control mechanism 75, valve
76 and liquid feeding means 77 constitute, together, a
temperature-control-medium supply system 102.
[0075] Additionally, in the top face of the support member 51, a
heater 51a connected with a power source 110 is provided as a part
of the temperature control mechanism. The heater 51a is adapted for
heating the electrode plate 54 up to, for example, 60.degree. C. to
200.degree. C., via the support member 51 and gas diffusion member
54a. On a top face of the insulating member 52 beside the heater
51a, a temperature detection means 51b, such as a thermocouple or
the like, is provided. Thus, the temperature of the central portion
of the bottom face of the electrode plate 54 can be measured,
indirectly, based on a temperature detected on the top face of the
insulating member 52. With such detection of the temperature of the
electrode plate 54 by the temperature detection means 51b, a
control unit 10, as will be described later, can control the
temperature of the electrode plate 54, by controlling the
temperature of the heater 51a as well as by controlling the
temperature and flow rate of the temperature control medium flowed
through the temperature control flow passage 71. It is noted that
the support member 51 is grounded, and that FIG. 3 shows the
support member 51 when it is seen from below.
[0076] This etching apparatus includes, as shown in FIG. 4, the
control unit 10 composed of, for example, a computer, as a means
for controlling an injection amount of the dielectric after reading
the injection amount. The control unit 10 includes a data
processing unit or the like, which is composed of a CPU 11, a
memory 12, a program 13 and a work memory 14 for the working. The
memory 12 has storage regions respectively provided for a kind of
each process (recipe). Namely, in each of the storage regions of
the memory 12, values of the processing conditions for each
process, including a kind of each processing gas, a processing
pressure, a processing temperature, a processing time, a gas flow
rate, a frequency and power of the high frequency power and the
like; and data, such as the amount (volume) of the dielectric
supplied into the recess 57, temperature of the electrode plate 54
and the like, are written, respectively. In this case, the amount
(volume) of the dielectric and the temperature of the electrode
plate 54 have been obtained, in advance, for example, by
experiments and/or calculations, such that the in-plane uniformity
of the electric field of the plasma (or electron density) can be
adequately applicable to a selected process, upon changing the
processing gas into the plasma under the above processing
conditions, and such that a capacitor component due to the recess
57 and resistance (or resistivity) of the electrode plate 54 can be
set at predetermined values, respectively. More specifically, the
amount of the dielectric in the recess 57 and the temperature of
the electrode plate 54, for rendering the in-plane uniformity of
the electric field of the plasma applicable or preferable, can be
obtained for the following reasons.
[0077] Assuming that electrical capacitance of the capacitor
component provided by the recess 57, the relative permittivity of
the dielectric constituting the capacitor, an area of the electrode
also constituting the capacitor and a thickness of the dielectric
constituting the capacitor are expressed by C, .di-elect cons., S,
d, respectively, the following relation can be obtained.
C=.di-elect cons.(S/d) (1)
[0078] In this relational expression (1), the thickness d can be
controlled, by controlling the amount of the dielectric supplied
into the recess 57. As a result, the capacitance C of the capacitor
component due to the recess 57 can be changed.
[0079] For instance, when the capacitance C of the capacitor
component due to the recess 57 is decreased, impedance between the
upper electrode 50 and the table 30 will be increased. Thus,
apparent high frequency power supplied into the processing space 1
will be decreased, as such reducing the intensity of the electric
field of the plasma. Contrary, when the capacitance C of the
capacitor component due to the recess 57 is increased, the
impedance between the upper electrode 50 and the table 30 will be
decreased. Thus, the intensity of the electric field of the plasma
will be increased. Therefore, by controlling the capacitance C of
the capacitor component due to the recess 57, corresponding to the
in-plane distribution of the electric field of the plasma, or by
reducing the capacitance C of the capacitor component by injecting
the dielectric into the recess 57, in a region of higher intensity
of the electric field of the plasma (or central region of the wafer
W), the in-plane uniformity of the plasma can be positively
enhanced.
[0080] Further, assuming that a skin depth of the electrode plate
54 relative to the high frequency power supplied from the first
high-frequency power source 6a, the frequency of the high frequency
power supplied from the first high-frequency power source 6a,
magnetic permeability of the electrode plate 54, resistivity of the
electrode plate 54 and the ratio of the circumference of a circle
to its diameter are expressed by .delta., f, .mu., .rho., .pi.,
respectively, the following relation can be established.
.delta.=(2/.omega..mu..sigma.).sup.1/2, .omega.=2.pi.f,
.sigma.=1/.rho. (2)
[0081] Therefore, by controlling the temperature of the electrode
plate 54, the value .rho. in this relation (2) can be controlled.
Thus, with such control of the temperature of the electrode plate
54, an effect of the plasma due to the recess 57 can be changed,
thereby controlling the distribution of the electric field.
[0082] Namely, this embodiment is intended to control the amount of
the dielectric supplied into the recess 57 as well as the
temperature of the electrode plate 54. It should be appreciated
that each processing parameter may be calculated each time a
selected process is performed, without storing the amount of the
dielectric supplied into the recess 57 and temperature of the
electrode plate 54, in advance, in the memory 12.
[0083] The program 13 incorporates instructions, each provided for
sending a control signal to each part or unit of the etching
apparatus from the control unit 10, so as to drive the part or unit
to carry out each step as will be described later, thereby
performing a necessary process or transfer operation for the wafer
W. Additionally, the program 13 incorporates other instructions,
respectively provided for controlling the liquid feeding means 64,
77, valves 63, 67, 92 and flow-rate controller 93, so as to achieve
the amount of the dielectric and temperature of the electrode plate
54 written in the above memory 12. When each instruction of the
program 13 is executed by the CPU 11, the processing conditions are
read by the work memory 14, and the control signal (or signals)
corresponding to the conditions is then sent to each part or unit
of the etching apparatus. The program 13 (including a program
related to input and/or display operations of the processing
conditions) is first stored in a storage unit 15, i.e., a computer
storage medium, such as a flexible disk, a compact disk, an MO (or
magneto-optical disk) or the like, and is then installed into the
control unit 10.
[0084] Next, an operation of the etching apparatus will be,
described, with reference to FIGS. 5 and 6. First, a recipe of the
process that is about to be performed is selected, and the process
conditions corresponding to the selected recipe are then read by
the work memory 14 from the memory 12. Thereafter, as shown in FIG.
5, the valves 63, 67 are opened, while the liquid feeding means 64
is actuated to supply the dielectric into the recess 57 from the
dielectric supply source 65, such that the amount of the dielectric
in the recess 57 will correspond to the processing conditions. As
the dielectric is filled in the recess 57, an ambient gas, for
example, a nitrogen gas, filled in advance in the recess 57, is
purged by the dielectric toward the dielectric supply source 65 via
the dielectric discharge passage 62. Eventually, the nitrogen gas
is discharged to the outside of the etching apparatus via the gas
exhaust passage 66. Simultaneously, the temperature control medium
is flowed through the temperature control flow passage 71 by the
liquid feeding means 77, while the heater 51a is turned on. Thus,
the temperature of the electrode plate 54 can be controlled at a
predetermined temperature, for example, 90.degree. C.
[0085] Then, the gate valve 26 is opened, and the wafer W is
carried into the processing vessel 21 by a carrier means (not
shown), and placed on the table 30. On the surface of the wafer W,
for example, a silicon oxide film (not shown) is formed. In
addition, a patterned resist mask (not shown) is layered on the
silicon oxide film. Thereafter, the wafer W is chucked by the
electro-static chuck 34, while the flow rates of the temperature
control medium and heat conducting gas, respectively flowed through
the temperature control flow passage 37 and gas flow passage 38,
are controlled, respectively, to adjust the temperature of the
wafer W at, for example, 30.degree. C. Subsequently, the processing
gas, for example, C.sub.4F.sub.8/A.sub.r/O.sub.2, of a
predetermined flow rate is supplied into the processing vessel 21,
while the throughput of the vacuum exhaust system 23 is controlled
to set the interior of the processing vessel 21 at a desired degree
of vacuum.
[0086] Thereafter, predetermined high frequency power is supplied
to the table 30 from the first high-frequency power source 6a and
second high-frequency power source 6b, respectively, so as to
change the processing gas into the plasma as well as to introduce
the ions present in the plasma into the wafer W. At this time, if
the recess 57 (or dielectric) is not provided in the upper
electrode 50, the etching process would be progressed at a higher
speed around the central portion of the wafer W, as shown in FIG.
16, while the etching rate would be significantly lowered around
the periphery of the wafer W, as compared with the central portion.
However, by using the upper electrode 50 of this embodiment, the
amount of the dielectric in the recess 57 and the temperature of
the electrode plate 54 can be optionally controlled as described
above. Therefore, the intensity of the electric field (or electron
density) around the central portion of the wafer W can be
adequately decreased. Thus, as shown in FIG. 6, the intensity of
the electric field of the plasma can be substantially uniformed in
the surface of the wafer W, thereby rendering the etching rate
adequately uniform in the surface. It is noted that arrows depicted
in the plasma shown in FIG. 6 schematically express the intensity
of the electric field of the plasma, respectively.
[0087] Once the etching process is completed, the supply of the
high frequency power is stopped, and the supply of the processing
gas is also stopped. Thereafter, the processing vessel 21 is
evacuated, and the wafer W is then carried out from the processing
vessel 21. Then, in the case of further providing a desired process
to another wafer W that will be processed under different
conditions, the amount of the dielectric in the recess 57 and the
temperature of the electrode plate 54 are newly controlled,
corresponding to a new recipe, via the dielectric supply system 101
and temperature-control-medium supply system 102, in the same
manner as described above. In this case, if the amount of the
dielectric in the recess 57 is required to be increased, the valves
63, 67 are respectively opened, so that the dielectric can be
further supplied into the recess 57 by the liquid feeding means 64.
Contrary, if the amount of the dielectric in the recess 57 is
needed to be decreased, the valve 63 is closed while the valves 67,
92 are respectively opened, so that the nitrogen gas can be
supplied into the recess 57 from the discharge gas supply source
94. Consequently, the dielectric in the recess 57 can be discharged
toward the discharge supply source 65 via the dielectric discharge
passage 62.
[0088] According to this embodiment, by providing the recess 57 in
the support member 51 as well as the provision of the dielectric
supply passage 61 and dielectric discharge passage 62 both
communicated with the recess 57, the dielectric can be controllably
supplied into the recess 57. Additionally, the in-plane
distribution of the intensity of the electric field of the plasma
that will be changed, corresponding to the process conditions, such
as the kind of each wafer W (e.g., the composition of the film to
be etched and/or mask), kind of each processing gas and/or gas
pressure, is obtained in advance, by experiments and/or
calculations. Therefore the amount of the dielectric in the recess
57 can be optionally controlled to render the in-plane distribution
of the intensity of the electric field of the plasma substantially
uniformed. Thus, the in-plane distribution of the intensity of the
electric field of the plasma generated from the processing gas can
be uniformed with ease, as such providing the etching process with
higher in-plane uniformity, corresponding to various processing
conditions. Moreover, in addition to the control of the amount of
the dielectric in the recess 57, the resistance (or resistivity) of
the electrode plate 54 can be adequately controlled, by controlling
the temperature of the electrode plate 54. Therefore, as is also
demonstrated in several examples discussed below, the in-plane
distribution of the intensity of the electric field of the plasma
can be finely controlled.
[0089] Because the electrode plate 54 (and/or gas diffusion member
54a) is provided to cover the bottom face of the support member 51,
the recess 57 formed in the support member 51, including a face
joined to the electrode plate 54, is not exposed to the processing
space 1. Thus, occurrence of unwanted particles from each face of
the recess 57 can be suppressed or substantially eliminated.
[0090] In the above example, the diameter R of the recess 57 is 160
mm, and the depth t2 thereof is 5 mm. However, as seen in the
examples discussed below, the diameter R may be changed within a
range of approximately 100 to 300 mm, while the thickness t2 may be
set within a range of approximately 5 to 10 mm. Additionally, in
the above example, the amount of the dielectric in the recess 57
and the temperature of the electrode plate 54 are controlled or
changed together. However, only the amount of the dielectric
supplied into the recess 57 may be controlled, without any control
of the temperature of the electrode plate 54. As the material for
the electrode plate 54, for example, carbon or the like material
other than silicon can be used.
[0091] In the above example, the gas diffusion passage 56
configured for diffusing the processing gas into the gas diffusion
member 54a is provided. However, the electrode plate 54 may be
modified as shown in FIG. 7. Furthermore, as shown in FIG. 8, the
gas diffusion member 54a may be eliminated. Instead, the electrode
plate 54 may be directly contacted with the support member 51. In
this case, a gas introduction passage 121, extending through the
electrode plate 54 while being in communication with the gas supply
pipe 59, may be provided in the electrode plate 54. Additionally,
as shown in FIG. 8, a gas supply member 122a, having a downwardly
convex dome-like shape and a plurality of apertures formed therein,
may be provided on the bottom face of the electrode plate 54, such
that the gas supply member 122a can be in communication with the
gas introduction passage 121. In this manner, the processing gas
can be radially supplied onto the wafer W from the gas injection
ports 122 of the dome-like gas supply member 122a. With such
configuration, a similar effect to the above example can also be
obtained. It is noted that the recess 57 may be completely
surrounded by the support member 51.
[0092] Unlike the table 30 in which the electro-static chuck 34,
temperature control flow passage 37 or gas flow passage 38 are
provided as described above, the recess 57 is provided in the
support member 51, with pipes and wirings arranged in significantly
reduced numbers, as compared with the table 30. Therefore, such a
recess 57 can be formed easily. However, as shown in FIG. 9, the
recess 57 may be provided in the table 30 (or lower electrode 31).
In such a case, the lower electrode 31 serves as a
dielectric-injection-space-constituting member. In FIG. 9, the
recess 57 is located more adjacent the wafer W than that in the
above example. Therefore, the intensity of the electric field of
the plasma can be further uniformed due to the dielectric, thereby
to provide the etching process with much higher in-plane
uniformity. In this case, the thickness of the electrode of the
electro-static chuck 34 is set at, for example, 20 mm or less.
Additionally, in FIG. 9, the same parts described in the above
example are designated by the same reference numerals. Furthermore,
the recess 57 may be provided in both of the support member 51 and
table 30. While the processing gas is supplied onto the wafer W
from the upper electrode 50 in the above example, the supply manner
of the processing gas is not limited to this manner. For instance,
the gas supply pipe 60 may be provided laterally to the wafer
W.
[0093] In the above example, the fluorine-containing inert liquid
having a relative permittivity of 1.9 is used as the dielectric
supplied into the recess 57. However, other CF-type polymers or
CHF-type polymers (e.g., CFC-type liquids nonvolatile at a normal
temperature) having a relative permittivity within a range of
approximately 1 to 3 may also be used. Alternatively, as the
dielectric, powder formed from ceramics, e.g., Al.sub.2O.sub.3,
having a relative permittivity of approximately 1 to 20,
S.sub.iO.sub.2 (or glass wool) having a relative permittivity of
approximately 1 to 4 (or 1 to 7), powder of a resin, e.g., PTFE,
having a relative permittivity of approximately 2, and a nitrogen
(N.sub.2) gas having a relative permittivity of approximately 1 may
be used. Alternatively, the interior of the recess 57 may be
brought into a vacuum state (.di-elect cons.: 1), by suitably
providing a valve, a flow-rate controller and a vacuum pump (not
shown) to the dielectric discharge passage 62. Additionally, the
above dielectrics may be used in a mixed state.
[0094] Alternatively or additionally, several storage tanks may be
provided for storing therein each of such dielectrics as mentioned
above, so that the kind of each dielectric supplied into the recess
57 can be changed, corresponding to the various processing
conditions. In this case, the value .di-elect cons. in the above
relation can also be controlled. Thus, the distribution of the
intensity of the electric field can be controlled in a greater
range than in the above example. Furthermore, in the above example,
the dielectric can be circulated between the recess 57 and the
dielectric supply source 65 via the dielectric discharge passage
62. However, in the case of using the aforementioned gas as the
dielectric, such a gas may be discharged to the outside via the
dielectric discharge passage 62, without being circulated in the
system.
[0095] In the above example, the amount of the dielectric injected
into the recess 57 is controlled for each recipe. However, for
example, in such a case in which the in-plane distribution of the
intensity of the electric field of the plasma is changed during a
certain process provided to the wafer W, the amount of the
dielectric may be controlled during the process, in response to the
change.
[0096] As described above, one method for controlling the relative
permittivity of the upper electrode 50 has been discussed, with
respect to the case in which the intensity of the electric field of
the plasma around the central region of the wafer W is relatively
increased, by way of example. This invention can also be applied to
the case in which the intensity of the electric field of the plasma
in the central region of the wafer W is relatively lowered. In such
a case, the dielectric having a relatively high relative
permittivity may be supplied into the recess 57, or otherwise the
temperature of the electrode plate 54 may be lowered.
Alternatively, as described above, both of the amount of the
dielectric in the recess 57 and the temperature of the electrode
plate 54 may be controlled at the same time.
[0097] Other than such a lower-electrode-two-high-frequency-type
apparatus as described above, the present invention can also be
applied to an upper-and-lower-electrode-two-high-frequency-type
etching apparatus, as shown in FIG. 10. Also in this case, the
intensity of the electric field of the plasma in the surface of the
wafer W can be uniformed, thus providing the etching process with
significantly higher in-plane uniformity. Although not shown in
FIG. 10, the support member 51 is grounded via a low pass filter
(LPF), while the lower electrode 31 is grounded via a high pass
filter (HPF). Furthermore, in a structure as shown in FIG. 1, a
lower-electrode-one-high-frequency-type apparatus, which is not
provided with the second high-frequency power source 6b for
introducing the ions present in the plasma, is also applicable
herein.
[0098] Other than the etching process, this invention may also be
applied to another plasma processing apparatus configured for
performing the ashing process, CVD process or the like, with the
plasma.
[0099] Furthermore, the region in which the recess 57 is provided
is not limited to the region corresponding to the central portion
of the wafer W. For instance, the recess 57 may be provided to have
a ring-like shape, in a position corresponding to the periphery of
the wafer W, along the circumference of the upper electrode 50. As
the upper electrode 50 in this case, one construction can be
mentioned, by way of example. Namely, in this construction, a first
dielectric having a relative permittivity of, for example,
.di-elect cons.1, is embedded in the position corresponding to the
central portion of the wafer W, with a second dielectric of a
relative permittivity lower than .di-elect cons.1 being injected
into the recess 57, while surrounding the first dielectric.
EXAMPLES
[0100] In order to study influence on the plasma, due to the amount
of the dielectric of the upper electrode 50 and the temperature of
the electrode plate 54 in the present invention, the magnitude of a
sheath electric field (or voltage) was calculated, over a region
from the central position to the periphery of the wafer W, in a
position spaced away from and along the bottom face of the
electrode plate 54 (i.e., 3 mm lower than the bottom face of the
electrode plate 54), by simulation using Multiphysics (softwear
produced by Ansis Co., Ltd.), with the relative permittivity of the
upper electrode 50 being variously changed, as will be described
below. It should be appreciated that the sheath electric field was
used as an index for assessing the intensity of the electric field
of the plasma because the sheath electric field is directly
influenced by a state or condition (i.e., distribution of the
intensity of the electric field) of the plasma. In FIGS. 11 through
15, a ratio obtained by dividing each magnitude of the calculated
sheath electric field by a maximum value thereof in the surface of
the wafer W is shown, respectively. For the simulation, the
calculation was performed, on the assumption that the resistivity
of the plasma was 1.5 .OMEGA.m.
Example 1
[0101] Under the following conditions, the simulation as described
above was performed. In this simulation, the magnitude of the
sheath electric field was calculated, with the size of the recess
57 being fixed, while the relative permittivity of the dielectric
in the recess 57 and the resistivity of the electrode plate 54 were
changed, respectively.
(Simulation Conditions)
[0102] Diameter R of the recess 57: 100 mm
[0103] Thickness t2 of the recess 57: 5 mm
[0104] High frequency for the plasma generation: 100 MHz
[0105] Relative permittivity (.di-elect cons.) of the dielectric in
the recess 57: 1/3.8/10/50
[0106] Resistivity (.OMEGA.m) of the electrode plate 54:
no/0.02/0.5/1/5/10
[0107] As the material actually used for setting the dielectric in
the recess 57 at the relative permittivity as described above, a
vacuum (.di-elect cons.: 1), powder of silicon dioxide (.di-elect
cons.: 3.8), powder of ceramics, e.g., Al.sub.2O.sub.3 (.di-elect
cons.: 10 to 50) and the like can be mentioned. In the case of
setting the resistivity into the range as described above, each
desired range of the resistivity can be achieved, by controlling
the temperature of the electrode plate 54 as well as by controlling
a doping amount of suitable impurities, such as boron (B) and the
like, by properly doping them into the electrode plate 54.
(Simulation Results)
[0108] FIG. 11(a) shows a result obtained by calculating the sheath
electric field, without the electrode plate 54, while changing the
relative permittivity of the dielectric in the recess 57, and FIGS.
11(b) through 11(e) show results obtained by calculating the sheath
electric field, while changing the relative permittivity of the
dielectric in the recess 57, as described above, as well as
changing the resistivity of the electrode plate 54, respectively.
In FIGS. 11(b) through 11(e), a value shown in FIG. 11(a), which
was calculated without the electrode plate 54, is also shown, as a
reference. It is noted that each legend shown in FIGS. 11(b)
through 11(e) designates the resistivity of the electrode plate
54.
[0109] With this simulation, it was found that the intensity of the
electric field of the plasma over a region corresponding to the
recess 57 (i.e., a region from the center of the wafer W to an
approximately 50 mm radial point) can be reduced by gradually
decreasing the relative permittivity of the recess 57. Such
reduction of the intensity of the electric field of the plasma can
be attributed to the fact that the high frequency power for
generating the plasma, supplied into the processing space 1, is
locally decreased in the region corresponding to the recess 57. In
addition, it was found that the intensity of the electric field of
the plasma can be controlled, over the whole surface of the wafer
W, by changing the resistivity of the electrode plate 54 together
with the relative permittivity of the recess 57. Specifically, with
decrease of the resistivity of the electrode plate 54, a gradient
of the change in the intensity of the electric field of the plasma
at a point corresponding to an outer periphery of the recess 57
(i.e., the 50 mm radial point from the center of the wafer W)
becomes more gentle.
[0110] Therefore, even in the case in which the intensity of the
electric field of the plasma is considerably increased in the
central portion of the wafer W as described above, the magnitude of
the sheath electric field (or intensity of the electric field of
the plasma) can be controlled, corresponding to each state or
condition of the plasma (i.e., the processing conditions or the
like), in order to enhance the in-plane uniformity, by controlling
the amount of the dielectric supplied into the recess 57 and the
temperature of the electrode plate 54. Thus, the wafer W can be
etched with higher in-plane uniformity.
Example 2
[0111] Another simulation similar to the simulation in the above
Example 1 was carried out, with the recess 57 having a 200 mm
diameter R. As shown in FIGS. 12(a) to 12(e), it was found that the
intensity of the electric field of the plasma can be reduced, over
the region corresponding to the recess 57 (i.e., a region from the
center of the wafer W to an approximately 100 mm radial point) can
be reduced by gradually decreasing the relative permittivity of the
recess 57, in the same manner as in the above simulation.
Similarly, it was found that the intensity of the electric field of
the plasma can be controlled, over the whole surface of the wafer
W, by changing the resistivity of the electrode plate 54 together
with the relative permittivity of the recess 57.
[0112] Additionally, as shown in FIG. 12(f), the intensity of the
electric field of the plasma can be similarly controlled, by
changing the relative permittivity of the dielectric in the recess
57 as well as by changing the thickness t2 of the recess 57, from 5
mm to 1.31 mm or 0.5 mm.
Example 3
[0113] Next, as shown in FIG. 13, still another simulation similar
to the simulation in the above Example 1 was carried out, with the
recess 57 having a 300 mm diameter R. Also in this simulation, it
was found that the intensity of the electric field of the plasma
can be reduced, over the region corresponding to the recess 57
(i.e., a region from the center of the wafer W to an approximately
150 mm radial point) can be reduced by gradually decreasing the
relative permittivity of the recess 57, in the same manner as
described above. Again, it was found that the intensity of the
electric field of the plasma can be controlled, over the whole
surface of the wafer W, by changing the resistivity of the
electrode plate 54 together with the relative permittivity of the
recess 57. From these results, it was found that the diameter R of
the recess 57 is preferably set at a value less than the diameter
of the support member 51, for example, 300 mm or less, because the
sheath electric field (or intensity of the electric field of the
plasma) is changed, using each end (or peripheral end) of the
dielectric in the recess 57 as a node (or fixed end).
Example 4
[0114] Next, in the above Example 3, another simulation for
calculating the magnitude of the sheath electric field was carried
out, with the thickness t2 of the recess 57 being set at 10 mm,
while the relative permittivity of the dielectric in the recess 57
and the resistivity of the electrode plate 54 were respectively
changed.
[0115] As a result, as shown in FIG. 14, it was found that the
magnitude of the sheath electric field can be further reduced than
the result of the above Example 3 (t2: 5 mm), by setting the
thickness t2 of the recess 57 at 10 mm. Thus, it was found that the
intensity of the electric field of the plasma can be controlled in
a greater range by increasing the thickness t2 of the recess
57.
Example 5
[0116] In this example, still another simulation was carried out,
with the size of the recess 57 and the relative permittivity of the
dielectric in the recess 57 being respectively fixed, while the
resistivity of the electrode plate 54 and the frequency of the high
frequency power used for the plasma generation were respectively
changed.
(Simulation Conditions)
[0117] Diameter R of the recess 57: 300 mm
[0118] Thickness t2 of the recess 57: 5 mm
[0119] Relative permittivity (.di-elect cons.) of the dielectric in
the recess 57: 1
[0120] High frequency for the plasma generation: 2/13.6/40/100/200
MHz
[0121] Resistivity (.OMEGA.m) of the electrode plate 54:
0.5/1/5/10
(Simulation Results)
[0122] As a result, as shown in FIG. 15, it was found that the
sheath electric field will be changed into a greater wave form,
with increase of the frequency of the high frequency power. In
addition, it was found that the degree of this change will be
higher, with increase of the resistivity of the electrode plate
54.
[0123] From the results of the above Experiments 1 through 5, it
was found that the distribution of the sheath electric field can be
variously changed, by suitably changing the diameter R, thickness
t2 and relative permittivity of the recess 57 (or amount and/or
kind of each dielectric supplied into the recess 57) as well as by
changing the resistivity of the electrode plate 54. Accordingly, it
was found that the in-plane uniformity of the intensity of the
electric field of the plasma can be substantially enhanced, by
controlling the amount and/or kind of each dielectric supplied into
the recess 57, dimensions of the recess 57, temperature of the
electrode plate 54 and the like, in order to reduce or eliminate
unwanted change of the intensity of the electric field of the
plasma, even in the case in which the in-plane uniformity of the
electron density of the plasma may tend to be considerably
deteriorated by changing the frequency of the high frequency power
and/or other processing parameters. This can be achieved, by
carrying out the experiments and/or simulations as described above,
in advance, in order to check or estimate how the intensity of the
electric field will be changed. It is noted that each legend shown
in FIG. 15 denotes the frequency of the high frequency power.
* * * * *