U.S. patent application number 11/354506 was filed with the patent office on 2006-06-22 for particle-removing apparatus for a semiconductor device manufacturing apparatus and method of removing particles.
Invention is credited to Natsuko Ito, Tsuyoshi Moriya, Fumihiko Uesugi.
Application Number | 20060131272 11/354506 |
Document ID | / |
Family ID | 14291408 |
Filed Date | 2006-06-22 |
United States Patent
Application |
20060131272 |
Kind Code |
A1 |
Ito; Natsuko ; et
al. |
June 22, 2006 |
Particle-removing apparatus for a semiconductor device
manufacturing apparatus and method of removing particles
Abstract
In a semiconductor device manufacturing apparatus that
processing a substrate by applying a voltage to a gas to create a
plasma, positively charged particles are trapped or guided at the
instant that the cathode voltage is stopped, by an electrode to
which is imparted a negative voltage, so as to prevent particles
reaching the substrate.
Inventors: |
Ito; Natsuko; (Tokyo,
JP) ; Uesugi; Fumihiko; (Tokyo, JP) ; Moriya;
Tsuyoshi; (Tokyo, JP) |
Correspondence
Address: |
Muirhead and Saturnelli, LLC
Suite 1001
200 Friberg Parkway
Westborough
MA
01581
US
|
Family ID: |
14291408 |
Appl. No.: |
11/354506 |
Filed: |
February 15, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09971463 |
Oct 5, 2001 |
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11354506 |
Feb 15, 2006 |
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09685351 |
Oct 10, 2000 |
6423176 |
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09971463 |
Oct 5, 2001 |
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09290636 |
Apr 12, 1999 |
6184489 |
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09685351 |
Oct 10, 2000 |
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Current U.S.
Class: |
216/67 ;
156/345.47 |
Current CPC
Class: |
H01J 2237/022 20130101;
Y10S 156/916 20130101; H01J 37/32431 20130101; H01L 21/67069
20130101 |
Class at
Publication: |
216/067 ;
156/345.47 |
International
Class: |
C23F 1/00 20060101
C23F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 13, 1998 |
JP |
101090/1998 |
Claims
1-34. (canceled)
35. A particle-removing method for a semiconductor device
manufacturing apparatus comprising an etching processing chamber, a
pair of processing electrodes formed by an upper electrode and a
lower electrode, which are installed within said processing
chamber, and a susceptor that holds a substrate to be processed
onto the top of said lower electrode, a processing gas being
introduced into said etching processing chamber, and a prescribed
voltage being applied to said processing electrodes, so as to
generate a plasma of said gas, thereby processing the substrate on
the susceptor, wherein said method forming a plasma having a size
that extends greatly beyond said substrate, so that particles
within said processing chamber fall along the outer periphery of
said plasma, thereby being prevented from becoming attached to said
substrate.
36. A particle-removing apparatus comprising an etching processing
chamber, a pair of processing electrodes formed by an upper
electrode and a lower electrode, which are installed within said
processing chamber, and a susceptor that holds a substrate to be
processed onto the top of said lower electrode, a processing gas
being introduced into said etching processing chamber, and a
prescribed voltage being applied to said processing electrodes, so
as to generate a plasma of said gas, thereby processing the
substrate on the susceptor, wherein said apparatus comprising means
for forming a plasma having a size that extends greatly beyond said
substrate, so that particles within said processing chamber fall
along the outer periphery of said plasma, thereby being prevented
from becoming attached to said substrate.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a particle-removing
apparatus for a semiconductor device manufacturing apparatus and to
a method of removing particles, and more specifically it relates-to
a particle-removing apparatus that prevents the falling of
particles that are generated during a process onto a wafer, and to
a method for removing particles.
[0003] 2. Description of the Related Art
[0004] Particles that are generated in the process of manufacturing
a semiconductor device, and in particular in a process that makes
use of plasma, are a cause of reduced yield and a deterioration of
uptime. These particles can be caused by the peeling off of
substances that have been deposited within the process equipment by
reactions and by growth of substances generated by reaction within
the plasma. To prevent the falling of these particles onto a
substrate, as described in the Japanese Unexamined Patent
Publications (KOKAI) No. 5-29272 and No. 7-58033, there has been a
proposal of an apparatus in which the substrate is covered after a
process is completed.
[0005] FIG. 9 (a) is a drawing that shows a plasma etching
apparatus of the past, in which the reference numeral 2100 denotes
a processing chamber, inside which are provided an upper processing
electrode 2200 and a lower processing electrode 2300, the upper
processing electrode 2200 being grounded, and a high-frequency
power supply 2400 being connected to the lower processing electrode
2300.
[0006] Above the lower processing electrode 2300 there is provided
an electrostatic chuck electrode 2700, which is insulated by means
of an insulator 1900, a voltage being applied to this electrostatic
chuck electrode 2700 from a power supply 2600, so as to hold a
semiconductor substrate 3000. The processing chamber 2100 is
provided with an intake port 3100 for processing gas and an exhaust
port 3200. A cover 3600 is provided so that particles do not fall
onto the semiconductor substrate 3000.
[0007] FIG. 9 (b) illustrates the general equipment operation cycle
of a plasma etching process in a semiconductor device manufacturing
process.
[0008] This process is for the case of a cycle in which a single
substrate is processed. The substrate 3000, which is transported
from a transporting port 3800, is transported to within the
processing chamber 2100, at which point the process gas is
introduced from the process gas intake port 3100. When the pressure
within the processing chamber 2100 reaches a prescribed value, a
high-frequency voltage is applied from the power supply 2400, so as
to generated a plasma that etches the substrate 3000.
Simultaneously with the above, the substrate 3000 is held by the
electrostatic chuck. After completion of the etching, the supply of
the high-frequency voltage, the supply of the process gas, and the
electrostatic chuck are all stopped. After several seconds, an
inert gas that does not contribute to etching is supplied for a
prescribed amount of time in order to quickly purge the chamber of
the process gas. The substrate 3000, after completion of this
processing, is transported to outside the processing chamber 2100
from the transporting port 3800.
[0009] In an apparatus of the past as described above, in order to
prevent particles from falling onto the substrate 3000, the cover
3600 is provided over the substrate 3000. According to an
experiment by the inventor, however, in a semiconductor device
manufacturing process that uses plasma, the timing of the falling
of particles onto a substrate was shown to be intimately connected
with the operating status of the semiconductor device manufacturing
apparatus. Specifically, in the above-noted publications of the
past, there was absolutely no consideration given to the timing of
the covering of the substrate, this representing a major problem
with regard to not being able to prevent the attachment of
particles to the substrate.
[0010] Accordingly, it is an object of the present invention to
improve over the above-noted drawback in the prior art, in
particular by providing a novel particle-removing apparatus of a
semiconductor device manufacturing apparatus and a method of
removing particles whereby, by controlling the timing of the
covering by a cover provided over the substrate in accordance with
the processing condition-of the substrate, the attachment of
particles that are generated within the manufacturing apparatus
during a process that uses plasma to the substrate is
prevented.
[0011] It is another object of the present invention to provide
novel particle-removing apparatus of a semiconductor device
particle and method of removing particles whereby, by making use of
the characteristic that particles are positively charged,
attachment of the particles to the substrate is prevented without
the use of a cover or the like.
SUMMARY OF THE INVENTION
[0012] In order to achieve the above-noted object, the present
invention ad-opts the following basic technical constitution.
[0013] Specifically, a first aspect of a particle-removing
apparatus of a semiconductor device manufacturing apparatus
according to the present invention is a particle-removing apparatus
in which a high-frequency voltage is applied between an upper
electrode and a lower electrode so as to generate a plasma within a
processing chamber that processes a substrate located in the
processing chamber, in which is provided a cover that covers the
substrate, the substrate being covered by closing this cover, so as
to prevent the attachment of particles within the processing
chamber to the substrate, this particle-removing apparatus being
provided with a first control means for controlling the timing of
the drive of the above-noted cover, this control means performing
control so as to change the cover from the opened condition to the
closed condition immediately before stopping the application of the
high-frequency voltage.
[0014] In a second aspect of a particle-removing apparatus
according to the present invention, control is performed so as to
change the above-noted cover from the closed condition to the
opened condition in synchronization with a tranport operation of a
substrate-transporting apparatus that is provided in the
semiconductor device manufacturing apparatus.
[0015] In a third aspect of a particle-removing apparatus according
to the present invention, the timing of control of changing the
cover from the closed condition to the opened condition is
immediately before transporting the substrate after completion of
processing to outside the processing chamber.
[0016] In a fourth aspect of a particle-removing apparatus
according to the present invention, the timing of control of
changing the cover from the closed condition to the opened
condition is immediately after transporting the substrate after
completion of processing to outside the processing chamber.
[0017] In a fifth aspect of a particle-removing apparatus according
to the present invention, the timing of the control of changing the
cover from the closed condition to the opened condition is
immediately before the application of the high-frequency
voltage.
[0018] In a sixth aspect of a particle-removing apparatus according
to the present invention, in addition to imparting a potential to
the above-noted cover, a second control means, for controlling the
timing of application of the potential to the cover, is provided,
this second control means performing control so that the potential
is imparted to the cover minimally from immediately before the
stopping of application of the high-frequency voltage to several
seconds after the starting of introduction of a purging gas.
[0019] In a seventh aspect of a particle-removing apparatus
according to the present invention, the above-noted potential is
imparted minimally until immediately before the introduction of the
purging gas.
[0020] In an eighth aspect of a particle-removing apparatus
according to the present invention, the above-noted potential is
imparted until the time at which the substrate is transported to
outside the processing chamber.
[0021] In a ninth aspect of a particle-removing apparatus according
to the present invention, the above-noted potential either is
equivalent to a self-bias potential that appears on the lower
electrode of the processing electrodes or has the same polarity- as
and a larger absolute value than the above-noted self-bias
potential.
[0022] In a tenth aspect of a particle-removing, apparatus
according to the present invention, the above-noted potential is a
potential that is equivalent to the potential on the lower
electrode of the processing electrodes.
[0023] A first aspect of a particle-removing method according to
the present invention is a particle-removing method in a
semiconductor device manufacturing apparatus in which a
high-frequency voltage is applied between an upper electrode and a
lower electrode so as to generate a plasma within a processing
chamber that processes a substrate located in the processing
chamber, in which is provided a cover that covers the substrate,
the substrate being covered by closing this cover, so as to prevent
the attachment of particles within the processing chamber to the
substrate, this particle-removing method performing control so as
to change the cover from the opened condition to the closed
condition immediately before stopping the application of the
high-frequency voltage.
[0024] In a second aspect of a particle-removing method according
to the present invention, control is performed so as to change the
above-noted cover from the closed condition to the opened condition
in synchronization with a transport operation of a substrate
transport apparatus that is provided in the semiconductor device
manufacturing apparatus.
[0025] A third aspect of a particle-removing method according to
the present invention is a particle-removing method apparatus in a
semiconductor device manufacturing apparatus in which a
high-frequency voltage is applied between an upper electrode and a
lower electrode so as to generate a plasma within a processing
chamber that processes a substrate located in the processing
chamber, in which is provided a cover that covers the substrate,
the substrate being covered by closing this cover, so as to prevent
the attachment of particles within the processing chamber to the
substrate, this particle-removing method having a first step of
changing the cover from the opened condition to the closed
condition, a second step of stopping the application of the
high-frequency voltage immediately after the cover is placed in the
closed condition, and a third step of imparting a potential to the
above-noted cover.
[0026] An eleventh aspect of a particle-removing apparatus of a
semiconductor device manufacturing apparatus according to the
present invention is a particle-removing apparatus in a
semiconductor device manufacturing apparatus that has an etching
processing chamber, a pair of processing electrodes formed by an
upper electrode and a lower electrode, which are installed within
the processing chamber, and a susceptor that holds a substrate to
be processed onto the top of the above-noted lower electrode, a
processing gas being introduced into the etching processing chamber
and a prescribed voltage being applied to the above-noted
processing electrodes, so as to generate a plasma thereof, thereby
processing the substrate on the above-noted susceptor, this
particle-removing apparatus being provided with a particle-removing
electrode for the purpose of removing particles inside the
processing chamber, a negative voltage being applied to this
particle-removing electrode, thereby causing removal of charged
particles in the processing chamber.
[0027] In a twelfth aspect of a particle-removing apparatus
according to the present invention, the above-noted
particle-removing electrode is provided between the upper electrode
and the lower electrode.
[0028] In a thirteenth aspect of a particle-removing apparatus
according to the present invention, an exhaust port is provided on
a side wall of the etching processing chamber in the region in
which the particle-removing electrode is provided.
[0029] In a fourteenth aspect of a particle-removing apparatus
according to the present invention, the particle-removing electrode
is provided over the above-noted lower electrode, in a manner so as
to surround the substrate.
[0030] In a fifteenth aspect of a particle-removing apparatus
according to the present invention, the particle-removing electrode
is provided between the processing electrodes and a processing
chamber side wall.
[0031] In a sixteenth aspect of a particle-removing apparatus
according to the present invention, the particle-removing electrode
is an attachment-preventing plate that prevents attachment of
sediments onto a wall surface of the processing chamber.
[0032] In a seventeenth aspect of a particle-removing apparatus
according to the present invention, the particle-removing electrode
is provided either within a gas intake or in the region of a gas
exhaust port of the etching processing chamber.
[0033] An eighteenth aspect of a particle-removing apparatus of a
semiconductor device manufacturing apparatus according to the
present invention is a particle-removing apparatus in a
semiconductor device manufacturing apparatus that has an etching
processing chamber, a pair of processing electrodes formed by an
upper electrode and a lower electrode, which are installed within
the processing chamber, and a susceptor that holds a substrate to
be processed onto the top of the above-noted lower electrode, a
processing gas being introduced into the etching processing chamber
and a prescribed voltage being applied to the above-noted
processing electrodes, so as to generate a plasma of the gas,
thereby processing the substrate on the susceptor, this
particle-removing apparatus having a gas exhaust port of the
processing chamber that is formed by an electrically conductive
material, to which a negative voltage is applied so as to remove
charged particles from within the processing chamber.
[0034] A nineteenth aspect of a particle-removing apparatus of a
semiconductor device manufacturing apparatus according to the
present invention is a particle-removing apparatus in a
semiconductor device manufacturing apparatus that has an etching
processing chamber, a pair of processing electrodes formed by an
upper electrode and a lower electrode, which are installed within
the processing chamber, and a susceptor that holds a substrate to
be processed onto the top of the above-noted lower electrode, a
processing gas being introduced into the etching processing chamber
and a prescribed voltage being applied to the above-noted
processing electrodes, so as to generate a plasma of the gas,
thereby processing the substrate on the susceptor, this
particle-removing apparatus being provided, between the upper
electrode and the lower electrode, with an electrically conductive
grid-configured material for the purpose of removing particles, a
negative voltage being applied to the grid-configured material, so
as to remove charged particles from within the processing
chamber.
[0035] A twentieth aspect of a particle-removing apparatus or a
semiconductor device manufacturing apparatus according to the
present invention is a particle-removing apparatus in a
semiconductor device manufacturing apparatus that has an etching
processing chamber, a pair of processing electrodes formed by an
upper electrode and a lower electrode, which are installed within
the processing chamber, and a susceptor that holds a substrate to
be processed onto the top of the above-noted lower electrode, a
processing gas being introduced into the etching processing chamber
and a prescribed voltage being applied to the above-noted
processing electrodes, so as to generate a plasma of the gas,
thereby processing the substrate on the susceptor, this
particle-removing apparatus being provided, in the region of
substrate, with a particle-removing electrode for the purpose of
removing particles, a negative voltage having an absolute value
that is greater than the self-bias voltage of the above-noted lower
electrode being applied to this particle-removing electrode, so as
to prevent the falling of particles within the processing chamber
onto the substrate.
[0036] A twenty-first aspect of a particle-removing apparatus of a
semiconductor device manufacturing apparatus according to the
present invention is a particle-removing apparatus in a
semiconductor device manufacturing apparatus that has an etching
processing chamber, a pair of processing electrodes formed by an
upper electrode and a lower electrode, which are installed within
the processing chamber, and a susceptor that holds a substrate to
be processed onto the top of the above-noted lower electrode, a
processing gas being introduced into the etching processing chamber
and a prescribed voltage being applied to the above-noted
processing electrodes, so as to generate a plasma of the gas,
thereby processing the substrate on the susceptor, a prescribed
bias being added to the voltage that is applied to the lower
electrode, this being varied in the same manner as the self-bias
voltage, thereby causing charged particles to be directed toward
the lower electrode, so as to prevent these particles from falling
onto the above-noted substrate.
[0037] In a twenty-second aspect of a particle-removing apparatus
according to the present invention, a laser apparatus is provided
for the purpose of detecting the occurrence of the above-noted
particles, light from this laser apparatus being shined in an area
surrounding the above-noted upper electrode so as to detect the
presence of particles inside the processing chamber, and a third
control means being further provided for the purpose of applying a
negative voltage to the particle-removing electrode, based on the
results of this detection.
[0038] A twenth-third aspect of a particle-removing apparatus of a
semiconductor device manufacturing apparatus according to the
present invention is a particle-removing apparatus in a
semiconductor device manufacturing apparatus that has an etching
processing chamber, a pair of processing electrodes formed by an
upper electrode and a lower electrode, which are installed within
the processing chamber, and a susceptor that holds a substrate to
be processed onto the top of the above-noted lower electrode, a
processing gas being introduced into the etching processing chamber
and a prescribed voltage being applied to the above-noted
processing electrodes, so as to generate a plasma thereof, thereby
processing the substrate on the above-noted susceptor, this
particle-removing apparatus being provided with a electrically
conductive planar particle-removing electrode for the purpose of
removing particles inside the processing chamber, a negative
voltage being applied to this particle-removing electrode, thereby
causing removal of charged particles in the processing chamber.
[0039] In a twenty-fourth aspect of a particle-removing apparatus
according to the present invention, the above-noted
particle-removing electrode is in the form of a grids-configured
electrically conductive electrode.
[0040] In a twenty-fifth aspect of a particle-removing apparatus
according to the present invention, the above-noted negative
voltage is applied after the completion of etching.
[0041] In a twenty-sixth aspect of a particle-removing apparatus
according to the present invention, the above-noted negative
voltage is applied during transport of the substrate.
[0042] A fourth aspect of a particle-removing method of a
semiconductor device manufacturing apparatus according to the
present invention is a particle-removing method for a semiconductor
device manufacturing apparatus that has an etching processing
chamber, a pair of processing electrodes formed by an upper
electrode and a lower electrode, which are installed within the
processing chamber, and a susceptor that holds a substrate to be
processed onto the top of the above-noted lower electrode, a
processing gas being introduced into the etching processing
chamber, a prescribed voltage being applied to the above-noted
processing electrodes, so as to generate a plasma of the gas,
thereby processing the substrate on the susceptor, and a
particle-removing electrode for the purpose of removing particles
being provided inside the processing chamber, whereby, after
completion of the etching of the substrate, a negative voltage is
applied to the particle-removing electrode, so that charged
particles inside the processing chamber are guided to this
particle-removing electrode and caused to be attached to the
particle-removing electrode, thereby preventing the particles from
becoming attached to the substrate.
[0043] In a fifth aspect of a particle-removing method according to
the present invention, after the application of the negative
voltage to the particle-removing electrode, the etching gas in the
processing chamber is exhausted.
[0044] A sixth aspect of a particle-removing method of a
semiconductor device manufacturing apparatus according to the
present invention is a particle-removing method for a semiconductor
device manufacturing apparatus that has an etching processing
chamber, a pair of processing electrodes formed by an upper
electrode and a lower electrode, which are installed within the
processing-chamber, and a susceptor that holds a substrate to be
processed onto the top of the above-noted lower electrode, a
processing gas being introduced into the etching processing
chamber, and a prescribed voltage being applied to the above-noted
processing electrodes, so as to generate a plasma of the gas,
thereby processing the substrate on the susceptor, wherein a gas
exhaust port of the processing chamber is formed of an electrically
conductive material, and a negative voltage is applied to this
exhaust port, so as to guide charged particles toward the gas
exhaust port and simultaneously exhaust the etching gas from within
the processing chamber.
[0045] An seventh aspect of a particle-removing method of a
semiconductor device manufacturing apparatus according to the
present invention is a particle-removing method for a semiconductor
device manufacturing apparatus that has an etching processing
chamber, a pair of processing electrodes formed by an upper
electrode and a lower electrode, which are installed within the
processing chamber, and a susceptor that holds a substrate to be
processed onto the top of the above-noted lower electrode, a
processing gas being introduced into the etching processing
chamber, and a prescribed voltage being applied to the above-noted
processing electrodes, so as to generate a plasma of the gas,
thereby processing the substrate on the susceptor, wherein by
causing the size of the generated plasma to greatly extend beyond
the substrate, particles inside the processing chamber are caused
to fall along the periphery of the plasma, so that they are
prevented from becoming attached to the substrate.
[0046] A particle-removing apparatus for a semiconductor device
manufacturing apparatus according to the present invention is a
particle-removing apparatus for a semiconductor device
manufacturing apparatus in which a high-frequency voltage is
applied between an upper electrode and a lower electrode to cause a
plasma within the processing chamber so as to process a substrate
therewithin, a cover that covers the substrate being provided, the
substrate being covered by changing cover to the closed condition,
so as to prevent particles within the processing chamber from
becoming attached to the substrate, and a first control means that
controls the timing of the drive timing of the cover being also
provided, this first control means performing control so that the
cover is changed from the opened condition to the closed condition
immediately before stopping the application of the above-noted
high-frequency voltage applied between an upper electrode and a
lower electrode, and so that the cover is changed from the closed
condition to the opened condition in synchronization with a
transporting operation of a substrate transport apparatus provided
in the semiconductor device-manufacturing apparatus.
[0047] Therefore, by driving the cover so as to cover the substrate
immediately before particles are generated, the attachment of the
particles to the substrate is prevented.
[0048] Additionally, by imparting an appropriate potential to the
cover, the cover has a dust-collecting action, enabling even more
effective prevention of attachment of the particles to the
substrate.
[0049] Next, yet another aspect of an embodiment of the present
invention will be described.
[0050] FIG. 21 is a photograph of the behavior of particles in a
plasma, inserted into a schematic representation of the apparatus.
The right edge of the drawing corresponds to the region at the
center of the process apparatus, and the left edge corresponds to
the region of the wall of the process apparatus.
[0051] Particles are trapped in a sheath region in proximity to the
upper electrode as shown in FIG. 21 and, at the instant the plasma
collapses, so that the particles in the region of the upper
electrode fly toward the outer walls by the potential of the
afterglow plasma. In the center part of the chamber, however, the
particles fall downward around the outside of the plasma, and in
the region of the lower electrode, this being the region of the
wafer, it can be seen that the negative self-bias-potential causes
the particles to fly towards the wafer.
[0052] From the above-noted results, the particles are seen to be
positively charged, and the basis of the present invention is the
use of this fact to remove the particles using electrostatic
induction.
[0053] FIG. 9 (b) shows an example of the relationship between the
number of particles that are generated in the etching apparatus
during operation, and the operation-condition of the apparatus at
that time.
[0054] The apparatus that is shown in FIG. 9 (a) is an etching
apparatus of the past that has flat parallel processing
electrodes.
[0055] FIG. 9 (b) is a representation of a cycle of processing one
substrate. When the substrate is transported to inside the
processing chamber from the transporting port, the processing gas
is supplied and, when the pressure within the processing chamber
reaches a prescribed value, a high-frequency voltage is applied, so
as to generate a plasma, thereby causing etching of the substrate.
When this is done, the substrate is held by the susceptor on the
top of the lower electrode.
[0056] After completion of the above-noted etching, the supply of
the high-frequency voltage, the supply of the process gas, and the
electrostatic chucking are all stopped. After several seconds, an
inert gas that does not contribute to etching is supplied for a
prescribed amount of time in order to quickly purge the chamber of
the process gas, this causing the pressure within the processing
chamber to rise.
[0057] The substrate, after completion of this processing, is
transported to outside the processing chamber from the transporting
port. In the drawing, the number of particles P represented by the
ellipses is the result of introducing the light from a laser into
the region over the substrate in the processing chamber, and using
a CCD camera to photograph the light scattered by particles that
traverse this laser light, a signal that indicates the operating
condition of the etching apparatus being simultaneously captured.
The number shown is the accumulated number obtained from the
processing of 25 substrates.
[0058] From FIG. 9 (b), it is clear that the occurrence of
particles P during etching corresponds to the operating condition
of the apparatus. That is, while there is almost no particle
generation during etching, when the etching is completed, there is
a time when a large number of particles are generated, and the
frequency of generation of particles is high when the purging gas
is introduced.
[0059] A detailed examination of the images obtained from the light
scattered by the particles revealed that the traces of particles at
the time of the completion of the etching exhibit a tendency to be
directed toward the substrate, and a tendency to be directed toward
the exhaust port when the purging gas is introduced.
[0060] From the above, it can be envisioned that because the
high-frequency power supply is stopped when the etching is
completed, particles that float during etching fall and, because
the viscous flow of the processing gas is small, the particles fly
toward the substrate, on which all of its electrical charge have
not been removed.
[0061] It is further envisioned, however, that several seconds
after the completion of etching, purging gas is introduced, the
result being that the particles head toward the exhaust port with
the purging gas.
[0062] In the present invention, the wafer is covered when the
supply of voltage is stopped. Also, using the fact that the
particles in the processing chamber are positively charged, by
imparting a negative potential to an electrically conductive plate
or grid, the generated particles are trapped, or caused to migrate
toward the exhaust port, thereby preventing them from reaching the
substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0063] FIG. 1 is block diagrams that show a particle-removing
apparatus of a semiconductor device manufacturing apparatus
according to-the present invention.
[0064] FIG. 2 is a drawing that shows the configuration of a
particle-removing apparatus according to the present invention.
[0065] FIG. 3 is a drawing that shows the operational timing of a
substrate cover in the first embodiment of the present
invention.
[0066] FIG. 4 is a drawing that shows the operational timing of a
substrate cover in the second embodiment of the present
invention.
[0067] FIG. 5 is a drawing that shows the operational timing of a
substrate cover in the third embodiment of the present
invention.
[0068] FIG. 6 is a drawing that shows the timing of the application
of a potential to the substrate cover in the fourth embodiment of
the present invention.
[0069] FIG. 7 is a drawing that shows the timing of the application
of a potential to the substrate cover in the fifth embodiment of
the present invention.
[0070] FIG. 8 is a drawing that shows the timing of the application
of a potential to the substrate cover in the sixth embodiment of
the present invention.
[0071] FIG. 9 (a) is a drawing that shows the configuration of an
etching apparatus of the past, and FIG. 9 (b) is a drawing that
shows the relationship between the operating condition of an
etching apparatus and the number of particles generated.
[0072] FIG. 10 is a drawing that shows the operational timing in a
conventional etching apparatus.
[0073] FIG. 11 is drawing that shows the seventh embodiment of the
present invention.
[0074] FIG. 12 is drawing that shows the eight embodiment of the
present invention.
[0075] FIG. 13 is drawing that shows the ninth embodiment of the
present invention.
[0076] FIG. 14 is drawing that shows the tenth embodiment or the
present invention.
[0077] FIG. 15 is drawing that shows the eleventh embodiment of the
present invention.
[0078] FIG. 16 is drawing that shows the twelfth embodiment of the
present invention.
[0079] FIG. 17 is drawing that shows the thirteenth embodiment of
the present invention.
[0080] FIG. 18 is drawing that shows the fourteenth embodiment of
the present invention.
[0081] FIG. 19 is drawing that shows the fifteenth embodiment of
the present invention.
[0082] FIG. 20 is drawing that shows the sixteenth embodiment of
the present invention.
[0083] FIG. 21 is a photograph that show the movement of particles
in a plasma.
[0084] FIG. 22 is a drawing that shows the operational timing of a
substrate cover in the seventeenth embodiment of the present
invention.
[0085] FIG. 23 is a drawing that shows the operational timing of a
substrate cover in the eighteenth embodiment of the present
invention.
[0086] FIG. 24 is a drawing that shows the operational timing of a
substrate cover in the nineteenth embodiment of the present
invention.
[0087] FIG. 25 is a drawing that shows the timing of the
application of a potential to the substrate cover in the twentieth
embodiment of the present invention.
[0088] FIG. 26 is a drawing that shows the timing of the
application of a potential to the substrate cover in the
twenty-first embodiment of the present invention.
[0089] FIG. 27 is a drawing that shows the timing of the
application of a potential to the substrate cover in the
twenty-second embodiment of the present invention.
[0090] FIG. 28 is a cross-sectional view that shows the structure
of a general DC plasma processing apparatus.
[0091] FIG. 29 is a drawing that shows the twenty-third embodiment
of the present invention.
[0092] FIG. 30 is a drawing that shows the twenty-fourth embodiment
of the present invention.
[0093] FIG. 31 is a drawing that shows the twenty-fifth embodiment
of the present invention.
[0094] FIG. 32 is a drawing that shows the twenty-sixth- embodiment
of the present invention.
[0095] FIG. 33 is a drawing that shows the twenty-seventh
embodiment of the present invention.
[0096] FIG. 34 is a drawing that shows the twenty-eight embodiment
of the present invention.
[0097] FIG. 35 is a drawing that shows the twenty-ninth embodiment
of the present invention.
[0098] FIG. 36 is a drawing that shows the thirtieth embodiment of
the present invention.
[0099] FIG. 37 is a drawing that shows the thirty-first embodiment
of: the present invention.
[0100] FIG. 38 is a drawing that shows the thirty-second embodiment
of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0101] Embodiments of the present invention are described below in
detail, with reference being made to the relevant accompanying
drawings.
[0102] FIG. 1 (a) is a block diagram that show the structure of an
embodiment of the present invention, this being a semiconductor
device manufacturing apparatus.
[0103] This block diagrams shows a semiconductor device
manufacturing apparatus 4000 in which a high-frequency voltage is
applied between an upper electrode 2200 and a lower electrode 2300,
so as to generate a plasma inside a processing chamber 3100,
thereby processing a substrate 3000, a cover 3600 being provided
which covers the substrate, this cover 3600 being closed to cover
the substrate 3000, thereby preventing the attachment of particles
to the substrate 3000.
[0104] In the above-noted apparatus, there is provided a first
control means 200, which controls the drive timing of the cover
3600, this control means 200 performing control so that the cover
is changed from the opened condition to the closed condition
immediately before stopping the application of the high-frequency
voltage, and also performing control so that the cover 3600 is
changed from the closed condition to the opened condition in
synchronization with a transport operation of a substrate transport
apparatus 1600, which is provided in the semiconductor device
manufacturing apparatus 4000.
[0105] FIG. 1 (b) is a block diagram that shows the overall
configuration a plasma etching apparatus according to the present
invention, this being formed by a driving apparatus 400 for the
cover 3600, an etching gas supply apparatus 1200 for supplying
etching gas to inside the processing chamber 2100, a purging gas
supply apparatus 1300 for supplying purging gas to inside the
processing chamber so as to exhaust the etching gas therefrom, a
vacuum adjustment apparatus 1400 for the purpose of adjusting the
degree of vacuum inside the processing chamber, an exhausting
apparatus 1500 for exhausting the gas from within the processing
chamber, a substrate transporting apparatus 1600 for transporting
the substrate, a high-frequency (less than 10 GHz) power supply
2400 for generating a plasma, and a controller 1700, a DC power
supply 2600 for the electrostatic chuck that holds the substrate,
controller 1700, such as a microcomputer or sequencer or the like,
which controls a driving apparatus 400, an etching gas supply
apparatus 1200, a purging gas supply apparatus 1300, a vacuum
adjustment apparatus 1400, an exhausting apparatus 1500, a
substrate transporting apparatus 1600, a high-frequency power
supply 2400, and the configuration being such that the substrate
3000 is subjected to the prescribed processing.
[0106] In the above-noted apparatus 4000, the first control means
200 and a second control means 300 are included within the
controller 1700. Thus, the semiconductor device manufacturing
apparatus used in the present invention, with the exception of the
control of the cover 3600, has the same configuration as in the
past.
[0107] FIG. 9 (b) is a drawing that shows the relationship between
the number of particles P that are generated during plasma etching
and the operating condition of the etching apparatus.
[0108] In this drawing, the number of particles P that are
represented by the ellipses is the result of introducing the light
from a laser into the region over the substrate in the processing
chamber, and using a CCD camera to photograph the light scattered
by particles that traverse this laser light, a signal that
indicates the operating condition of the etching apparatus being
simultaneously captured, this number being the accumulated value
obtained by processing 25 substrates. The generation of particles P
during etching has a clear relationship to the operating condition
of the apparatus. That is, while there is almost no particle
generation during etching, when the etching is completed, there is
a time when a large number of particles are generated, and the
frequency of generation of particles is high when the purging gas
is introduced.
[0109] If a detailed examination is made of the images obtained-
from the light scattered by the particles, it is seen that the
traces of particles at the time of the completion of the etching
exhibit a tendency to be directed toward the substrate, and a
tendency to be directed toward the exhaust port when the purging
gas is introduced.
[0110] From the above, it can be envisioned that because the
high-frequency power supply is stopped when the etching is
completed, particles that float during etching fall and, because
the viscous flow of the processing gas is small, the particles fly
toward the substrate, on which all of its electrical charge have
not been removed. It is further envisioned, however, that several
seconds'after the completion of etching, purging gas is introduced,
the result being that the particles head toward the exhaust port
with the purging gas.
[0111] The embodiments of the present invention to be described
below were invented with the above-noted phenomenon as a basis.
[0112] The first to sixteenth embodiments of the present invention
described below all can be applied to an RF plasma CVD apparatus,
an RF plasma etching apparatus, and an RF plasma sputtering
apparatus. Unless specifically indicated, the descriptions of the
embodiments will be for the case of application to an RF plasma
etching apparatus. However, it shall be understood that these
embodiments can be applied as well to the above-noted other types
of RF processing apparatuses.
[0113] (First Embodiment)
[0114] The flow of cover operation timing in the first embodiment
of the present invention is shown in FIG. 3 (a). At the time t1,
immediately before the stopping of the high-frequency voltage, the
cover 3600 that covers the substrate 3000 is closed and, at the
instant that the high-frequency voltage is stopped, particles that
fall toward the substrate 3000 are caught by the cover 3600. The
cover 3600 remains closed during the introduction of the purging
gas, at which time there is a high frequency of generation of
particles and, after the introduction of the purging gas is
stopped, at the time t2, immediately before the processed substrate
is transported to outside the processing chamber 2100, the cover is
opened. Thus, during the period of time when many particles P would
fall onto the substrate, because the cover 3600 is in the closed
condition, thereby reliably covering the substrate 3000, the
attachment of the particles onto the substrate 3000 is
prevented.
[0115] The shape of the cover can be that of a single sheet, or
that of a plurality of blades, such as those of a camera shutter.
In contrast to the prior art, the present invention is not limited
in application to a plasma etching apparatus, and can be applied as
well to other apparatuses, such as a plasma CVD apparatus, which
uses plasma to perform processing.
[0116] As shown in FIG. 3 (b), the timing of the opening of the
cover can be established at time t21, which is immediately after
the transport of the processed substrate to outside the processing
chamber 2100.
[0117] (Second Embodiment)
[0118] The flow of cover operation timing in the second embodiment
of the present invention is shown in FIG. 4. At the time t1,
immediately before the stopping of the high frequency voltage, the
cover 3600 that covers the substrate 3000 is closed and, at the
instant that the high-frequency voltage is stopped, particles that
fall toward the substrate 3000 are caught by the cover 3600. After
the processed substrate 3000 is transported to outside the
processing chamber 2100, at the time t3, immediately before the
next substrate is transported into the processing chamber, the
cover 3600 is opened. Thus, by operating the cover 3600 in this
manner, attachment of particles that fall onto the substrate is
prevented.
[0119] (Third Embodiment)
[0120] The flow of cover operation timing in the third embodiment
of the present invention is shown in FIG. 5. At the time t4,
immediately before the application of the high-frequency voltage,
the cover 3600 that covers the substrate 3000 is opened and, at
time t1, immediately before the high-frequency voltage is stopped,
the cover is closed. By closing the cover when etching is not being
performed, particles occurring because of peeling from the upper
electrode 2200 or from the inside walls of the processing chamber
2000 are caught by the cover, thereby preventing the attachment of
these particles to the substrate.
[0121] Furthermore, in addition to the above-noted configurations,
it is possible to use a configuration in which a detection means is
provided that detects that the cover has been placed in the closed
condition, the result of the detection by this detection means
being used to turn off the high-frequency power supply 2400.
[0122] (Fourth Embodiment)
[0123] The flow of cover operation timing in the fourth embodiment
of the present invention is shown in FIG. 6 (a). In addition to the
first to the third embodiments, during the period of time from t5,
immediately before the stopping of the application of the
high-frequency voltage, to the time t6, several seconds after the
start of the introduction of the purging gas, a potential is
imparted to the cover 3600. Because even immediately after the
stopping of the application of the high-frequency voltage,
particles fall toward the charged substrate that has a residual
charge from the electrostatic chuck, this cover potential can be
selected as a value that is either equivalent to the self-bias
potential of the lower electrode 2300, or as a potential with the
same polarity as and a larger absolute value than the above-noted
self-bias potential. Particles that are generated immediately after
the stopping of application of the high-frequency voltage fall
toward the cover and are attracted to the cover 3600. Particles
that are generated after the introduction of the purging gas follow
the flow of the purging gas, and fall toward the exhaust port, so
that they do not become attached to the substrate.
[0124] The material of the cover 3600 can be the same conductive
material as the processing chamber 2100 inner wall, this being for
example an aluminum alloy and, to reduce the number of particles
that are generated, it can also have a metallic surface that is
covered with aluminum oxide or silicon oxide.
[0125] It is also possible, as shown in FIG. 6 (b), to impart the
potential at time t61, immediately before the introduction of the
purging gas.
[0126] (Fifth Embodiment)
[0127] The flow of cover operation timing in the fifth embodiment
of the present invention is shown in FIG. 7.
[0128] In the cases of the second and third embodiments of the
present invention, as shown in FIG. 4 and FIG. 5, it is possible to
impart a potential to the cover from the time t7, at which the
application of the high-frequency voltage is stopped, until time
t8, at which point the processed substrate has been completely
transported to outside the processing chamber, this cover potential
being selectable either as equivalent to the self-bias potential of
the lower electrode 2300, or as a potential with the same polarity
as and a larger absolute value than the above-noted self-bias
potential. Particles that are generated in the period from the time
immediately after the stopping of application of the high-frequency
voltage to the time the transporting port opens are collected by
the cover, and therefore do not become attached to the
substrate.
[0129] (Sixth Embodiment)
[0130] The flow of cover operation timing in the sixth embodiment
of the present invention is shown in FIG. 8.
[0131] In the cases of the second and third embodiments of the
present invention, as shown in FIG. 4 and FIG. 5, it is possible to
impart a potential to the cover, from the time that the cover is
started to be closed until the time the cover is opened. By making
the cover 3600 the same potential as the lower processing electrode
2300 during the application of the high-frequency voltage, there is
no discharge between the substrate 3000 and the cover 3600, thereby
enabling prevention of damage to the substrate and the generation
of particles between the cover and the substrate.
[0132] Then, after the application of the high-frequency voltage is
stopped, the cover potential is either made equivalent to the
self-bias potential, or a potential that has the same polarity as
and an absolute value that is greater than the self-bias value.
[0133] It is also possible to apply this embodiment to the first
embodiment.
[0134] (Seventh Embodiment)
[0135] FIG. 10 shows one typical operating cycle of an etching
apparatus generally used in a semiconductor device plant.
[0136] Etching is performed by introducing a highly reactive
processing gas such as chlorine into the processing chamber from a
spraying plate that also serves as the upper processing electrode
that is in opposition to the substrate and, when the pressure
reaches a prescribed pressure, applying a voltage between the
electrodes, so as to generate a plasma of the processing gas.
[0137] When etching is completed, the application of the
high-frequency voltage and the introduction of the processing gas
are stopped simultaneously and, after several seconds have elapsed,
a purging gas having a low reactivity, such as a halogen gas, is
introduced.
[0138] In an etching apparatus of the seventh embodiment of the
present invention, as shown in FIG. 11, the process gas supply is
stopped when the etching is completed. When this is done, it is
known that the particles have a positive charge and, by making use
of this phenomenon, by imparting a negative potential to an
electrically conductive particle-removing electrode 11 that is
provided between the upper processing electrode 2200 and lower
processing electrode 2300 inside the processing chamber 2100,
particles are forcibly removed. As long as there is no influence on
the process, the particle-removing electrode 11 can be any shape
such as that of a sheet or grid.
[0139] The large number of falling particles that are generated at
the instant that the high-frequency voltage is stopped are trapped
by the particle-removing electrode 11, thereby preventing their
reaching the substrate 3000.
[0140] It is also possible to adopt a configuration in which a
power supply controller 420 and a negative power supply 410 are
provided, whereby a negative potential is applied to the electrode
11 in synchronization with the completion of the etching.
[0141] (Eighth Embodiment)
[0142] FIG. 12 shows an etching apparatus into which a function has
been built to trap particles, using an attachment-prevention
shield.
[0143] In a semiconductor device manufacturing apparatus, an
attachment-prevention shield 12 is often used to prevent the
attachment of sediments that occur during processing onto the
chamber walls.
[0144] These attachment-prevention shields 12 are provided between
the processing electrodes 2200, 2300 and the side walls of the
processing chamber 2100, and intentionally cause sediments to be
deposited onto these attachment-prevention shields 12, and by
replacing the attachment-prevention shields 12, it is possible to
reduce the number of times the inside of the chamber needs to be
cleaned.
[0145] The attachment-prevention shield 12 is often made of an
electrically conductive metal, the attachment-prevention shield 12
being kept electrically insulated from the processing chamber, and
when the etching is completed the supply of processing gas is
stopped and a negative potential is imparted to the
attachment-prevention shield 12.
[0146] The large number of positively charged falling particles
that are generated at the instant that the high-frequency voltage
is stopped are pulled in by the negative potential on the
attachment-prevention shield 12 and trapped and ultimately are
trapped on the wall of the attachment-prevention shield 12, thereby
preventing their reaching the substrate 3000.
[0147] (Ninth Embodiment)
[0148] FIG. 13 shows an etching apparatus into which a function has
built to trap particles, using an electrically conductive grid
13.
[0149] Specifically, the grid 13 is provided between the processing
electrodes 2200, 2300 and the side walls of the processing chamber
2100, this grid 13 being installed so that it is electrically
insulated from the processing chamber and, when the etching is
completed, the supply of processing gas is stopped and a negative
potential is imparted to the grid 13.
[0150] The large number of positively charged particles that fall
when the high-frequency voltage is stopped are pulled in by the
negative potential of the grid 13, and are ultimately trapped by
this grid 13, so that they are prevented from reaching the
substrate.
[0151] (Tenth Embodiment)
[0152] FIG. 14 shows an etching apparatus in which a gas exhaust
port 14 at the bottom of the processing chamber is formed of an
electrically conductive material such as a metal, this gas exhaust
port 14 being electrically insulated, so that particles are guided
to the exhaust port and forcibly exhausted, the result being that
the particles do not fall onto the substrate.
[0153] That is, when the supply of the processing gas is stopped at
the completion of the etching, a negative potential is imparted to
the exhaust port 14, the result being that the large number of
positively charged particles that fall at the instant the
high-frequency voltage is stopped are pulled in toward the exhaust
port 14, which has a negative potential, these particles being
ultimately exhausted, so that they are prevented from reaching the
substrate.
[0154] (Eleventh Embodiment)
[0155] FIG. 15 shows an etching apparatus in which an electrically
conductive grid 13 is provided in proximity to the gas exhaust port
14, this grid serving to trap particles.
[0156] Specifically, the grid 13 is installed in front of the
exhaust port 14 so that it is electrically insulated with respect
to the chamber, the supply of the processing gas being stopped and
a negative potential being imparted to the grid 13 when etching is
completed.
[0157] The large number of positively charged particles that fall
at the instant the high-frequency voltage is stopped are pulled in
toward the grid 13 because of its negative potential, and are
ultimately trapped by the grid 13 or exhausted from the exhaust
port 14, so that they are prevented from reaching the
substrate.
[0158] (Twelfth Embodiment)
[0159] FIG. 16 shows the twelfth embodiment of the present
invention.
[0160] In this embodiment, the electrically conductive grid 13 is
installed between the upper electrode 2200 and the lower electrode
2300, and is placed in an electrically floating condition. By doing
this, during the process, that is during discharge, the grid 13
tracks to the potential of the plasma, so that it is in the
floating condition.
[0161] After the process is completed, when a negative potential is
imparted to the grid 13, particles are pulled in toward the
negative potential of the grid 13, thereby being prevented from
reaching the substrate. Then, in this condition, the semiconductor
substrate 3000 is transported.
[0162] (Thirteenth Embodiment)
[0163] FIG. 17 shows the thirteenth embodiment of the present
invention.
[0164] In this embodiment, a plasma PZ is generated that is
sufficiently large with respect to the semiconductor substrate
3000. This plasma PZ is generated in accordance with the diameters
of the upper electrode 2200 and the lower electrode 2300 and, in
the case of FIG. 17, this is a plasma that is generated to
considerably outside the substrate 3000.
[0165] By doing this, so that the plasma PZ extends greatly beyond
the substrate 3000, particles drop along the outer periphery of the
plasma PZ, thereby preventing them from falling onto the substrate
3000.
[0166] (Fourteenth Embodiment)
[0167] FIG. 18 shows the fourteenth embodiment of the present
invention.
[0168] In this embodiment, a donut-shaped electrode 15 is installed
over the lower electrode 2300 so as to surround the substrate 3000,
a negative voltage that has an absolute value that is greater than
the self-bias voltage being applied to the electrode 15, in which
case the applied voltage can be a DC voltage.
[0169] The timing of the application of the above-noted voltage is
the time that the process is completed and the time that the plasma
power supply is turned off.
[0170] A negative bias is applied with respect to the voltage
applied to the lower electrode 2300, which is the cathode
electrode, and this is caused to vary in the same manner as the
self-bias voltage.
[0171] By doing the above, positively charged particles are guided
to the electrode 15, thereby preventing them from falling onto the
substrate 3000.
[0172] (Fifteenth Embodiment)
[0173] FIG. 19 shows the fifteenth embodiment of the present
invention.
[0174] In this embodiment, a laser apparatus is introduced for the
purpose of monitoring the generation of particles. The location at
which the laser light is shined is the region under the anode
electrode, this being the upper electrode 2200. By adopting this
configuration, it is possible to detect particles at an early stage
that are trapped in the region near the plasma sheath.
[0175] Then, after the particles are detected, a negative voltage
is applied to the electrode 15, so as to collect the particles,
preventing them from falling onto the substrate 3000.
[0176] (Sixteenth Embodiment)
[0177] FIG. 20 shows the sixteenth embodiment of the present
invention.
[0178] In this embodiment, a particle-removing electrode 15 is
provided between the upper electrode 2200 and the lower electrode
2300, and a gate valve 17 is installed on a side wall of the
processing chamber near the particle-removing electrode 15, a
vacuum pump or other such exhausting apparatus being connected to
the outside thereof. A provision is also made to apply a negative
voltage to the electrode 15.
[0179] When the processing is completed and the voltage applied to
the cathode electrode, which is the lower electrode 2300, is cut
off, a negative voltage is applied to the electrode 15. By doing
this, particles are pulled toward the gate valve 17. When this
occurs, the gate valve 17 is simultaneously opened, so that the
particles are exhausted, thereby preventing the particle from
falling onto the substrate 3000.
[0180] In FIG. 19, the reference numeral 450 denotes a third
control means for the purpose of applying a negative voltage to the
particle-removing electrode 15, based on the results of the
detection of particles within the processing chamber.
[0181] All of the above-described first embodiment through
sixteenth embodiment can be applied in common to an RE plasma CVD
apparatus, an RE plasma etching apparatus, and an RE plasma
sputtering apparatus.
[0182] In contrast to the above, the seventeenth through
thirty-second embodiments to be described below can be applied in
common to a DC plasma CVD apparatus, a DC plasma etching apparatus,
and a DC plasma sputtering apparatus.
[0183] (Seventeenth Embodiment)
[0184] The flow of cover operation timing in the seventeenth
embodiment of the present invention is shown in FIG. 22.
[0185] At the time t11, immediately before the stopping of the DC
voltage, the cover 3600 that covers the substrate 3000 is closed
and, at the instant that the DC voltage is stopped, particles that
fall toward the substrate 3000 are caught by the cover 3600. The
cover 3600 remains closed during the introduction of the purging
gas, at which time there is a high frequency of generation of
particles and, after the introduction of the purging gas is
stopped, at the time t12, immediately before the processed
substrate is transported to outside the processing chamber 2100,
the cover is opened. Thus, during the period of time when many
particles P would fall onto the substrate, because the cover 3600
is in the closed condition, thereby reliably covering the substrate
3000, the attachment of the particles P onto the substrate 3000 is
prevented.
[0186] The shape of the cover can be that of a single sheet, or
that of a plurality of blades, such as those of a camera
shutter.
[0187] (Eighteenth Embodiment)
[0188] The flow of cover operation timing in the eighteenth
embodiment of the present invention is shown in FIG. 23. At the
time t11, immediately before the stopping of the DC voltage, the
cover 3600 that covers the substrate 3000 is closed and, at the
instant that the DC voltage is stopped, articles that fall toward
the substrate 3000 are caught by the cover 3600. After the
processed substrate 3000 is transported to outside the processing
chamber 2100, at the time t13, immediately before the next
substrate is transported into the processing chamber, the cover
3600 is opened. Thus, by operating the cover in this manner,
attachment of particles that fall onto the substrate is
prevented.
[0189] (Nineteenth Embodiment)
[0190] The flow of cover operation timing in the nineteenth
embodiment of the present invention is shown in FIG. 24.
[0191] At the time t14, immediately before the application of the
DC voltage, the cover that covers the substrate 3000 is opened and,
at time t11, immediately before the DC voltage is stopped, the
cover is closed. By closing the cover when etching is not being
performed, particles occurring because of peeling from the upper
electrode 2200 or from the inside walls of the processing chamber
2000 are caught by the cover, thereby preventing the attachment of
these particles to the substrate.
[0192] Furthermore, in addition to the above-noted configurations,
it is possible to use a configuration in which a detection means is
provided that detects that the cover 3600 has been placed in the
closed condition, the result of the detection by this detection
means being used to turn off the DC power supply 2400.
[0193] (Twentieth Embodiment)
[0194] The flow of cover operation timing in the twentieth
embodiment of the present invention is shown in FIG. 25.
[0195] In addition to the seventeenth to the nineteenth
embodiments, during the period of time from t15, immediately before
the stopping of the application of the DC voltage, to the time t16,
several seconds after the start of the introduction of the purging
gas, a potential is imparted to the cover 3600. Particles that are
generated immediately after the stopping of application of the DC
voltage fall toward and are attracted to the cover 3600. Particles
that are generated after the introduction of the purging gas follow
the flow of the purging gas, and fall toward the exhaust port, so
that they do not become attached to the substrate.
[0196] The material of the cover 3600 can be the same conductive
material as the processing chamber 2100 inner wall, this being for
example an aluminum alloy and, to reduce the number of particles
that are generated, it can also have a metallic surface that is
covered with aluminum oxide or silicon oxide.
[0197] (Twenty-First Embodiment)
[0198] The flow of cover operation timing in the twenty-first
embodiment of the present invention is shown in FIG. 26.
[0199] In the cases of the eighteenth and nineteenth embodiments of
the present invention, as shown in FIG. 23 and FIG. 24, it is
possible to impart a potential to the cover from the time t17, at
which the application of the DC voltage is stopped, until time t18,
at which point the processed substrate has been completely
transported to outside the processing chamber. Particles that are
generated in the period from the time immediately after the
stopping of application of the DC voltage to the time the
transporting port opens are collected by the cover, and therefore
do not become attached to the substrate.
[0200] (Twenty-Second Embodiment)
[0201] The flow of cover operation timing in the twenty-second
embodiment of the present invention is shown in FIG. 27.
[0202] In the cases of the eighteenth and nineteenth embodiments of
the present invention, as shown in FIG. 23 and FIG. 24, it is
possible to impart a potential to the cover, from the time that the
cover is started to be closed until the time the cover is opened.
By making the cover 3600 the same potential as the lower processing
electrode 2300 during 10 the application of the DC voltage, there
is no discharge between the substrate 3000 and the cover 3600,
thereby enabling prevention of damage to the substrate and the
generation of particles between the cover and the substrate.
[0203] Then, after the application of the DC voltage is stopped,
the cover potential is either made equivalent to the self-bias
potential, or a potential that has the same polarity as and an
absolute value that is greater than the self-bias value.
[0204] It is also possible to apply this embodiment to the
seventeenth embodiment.
[0205] (Twenty-Third Embodiment)
[0206] FIG. 28 shows one typical operating cycle of a DC plasma
processing apparatus generally used in a semiconductor device
plant.
[0207] In the twenty-third embodiment of a DC plasma processing
apparatus shown in FIG. 29, when the DC plasma processing is
completed, it is known that the particles have a positive charge
and, by making use of this phenomenon, by imparting a negative
potential to an electrically conductive particle-removing electrode
11, particles are removed. As long as there is no influence on the
DC plasma process, the particle-removing electrode 11 can be any
shape such as that of a sheet or grid.
[0208] The large number of falling particles that are generated at
the instant that the DC voltage is stopped are trapped by the
particle-removing electrode 11, thereby preventing their reaching
the substrate 3000.
[0209] (Twenty-Fourth Embodiment)
[0210] FIG. 30 shows a DC etching apparatus into which a function
has been built to trap particles, using an attachment-prevention
shield.
[0211] In a semiconductor device manufacturing apparatus, an
attachment-prevention shield 12 is often used to prevent the
attachment of sediments that occur during processing onto the
chamber walls.
[0212] These attachment-prevention shields intentionally cause
sediments to be deposited onto these attachment-prevention shields
12, and by replacing the attachment-prevention shields 12, it is
possible to reduce the number of times the inside of the chamber
needs to be cleaned.
[0213] The attachment-prevention shield 12 is often made of an
electrically conductive metal, the attachment-prevention shield 12
being kept electrically insulated from the processing chamber, and
when the etching is completed, a negative potential is imparted to
the attachment-prevention shield 12.
[0214] The large number of positively charged falling particles
that are generated at the instant that the DC voltage is stopped
are pulled in by the negative potential on the
attachment-prevention shield 12 and trapped and ultimately are
trapped on the wall of the attachment-prevention shield 12, thereby
preventing their reaching the substrate 3000.
[0215] (Twenty-Fifth Embodiment)
[0216] FIG. 31 shows an etching apparatus into which a function has
built to trap particles, using an electrically conductive grid
13.
[0217] Specifically, the grid 13 is installed so that it is
electrically insulated from the processing chamber and, when the
etching is completed, a negative potential is imparted to the grid
13.
[0218] The large number of positively charged particles that fall
when the DC voltage is stopped are pulled in by the negative
potential of the grid 13, and are ultimately trapped by this grid
13, so that they are prevented from reaching the substrate.
[0219] (Twenty-Sixth Embodiment)
[0220] FIG. 32 shows a DC plasma processing apparatus in which a
gas exhaust port 14 is formed at the bottom of the processing
chamber and is electrically insulated from the chamber, thereby
forcibly exhausting particles.
[0221] That is, in the above-noted particle-removing apparatus,
when the DC plasma processing is completed, a negative potential is
imparted to the exhaust port 14, the result being that the large
number of positively charged particles that fall at the instant the
DC voltage is stopped are pulled in toward the exhaust port 14,
which has a negative potential, these particles being ultimately
exhausted, so that they are prevented from reaching the substrate
3000.
[0222] (Twenty-Seventh Embodiment)
[0223] FIG. 33 shows an etching apparatus in which an electrically
conductive grid 13 is provided in proximity to the gas exhaust port
14, this grid serving to trap particles.
[0224] Specifically, the grid 13 is installed in front of the
exhaust port 14 so that it is electrically insulated with respect
to the chamber, a negative potential being imparted to the grid 13
when DC plasma processing is completed.
[0225] The large number of positively charged particles that fall
at the instant the DC voltage is stopped are pulled in toward the
grid 13 because of its negative potential, and are ultimately
trapped by the grid 13 or exhausted from the exhaust port 14, so
that they are prevented from reaching the substrate 3000.
[0226] (Twenty-Eighth Embodiment)
[0227] FIG. 34 shows the twenty-eighth embodiment of the present
invention.
[0228] In this embodiment, the electrically conductive grid 13 is
installed between the upper electrode 2200 and the lower electrode
2300, and is placed in an electrically floating condition. By doing
this, during the process, that is during discharge, the grid 13
tracks to the potential of the plasma, so that it is in the
floating condition.
[0229] After the process is completed, the grid 13 is connected to
a power supply 4400, and a discharge is caused between the grid 13
and the upper electrode 2200. When this is done, the- power supply
4400 is not connected to the lower electrode 2300.
[0230] Then, in this condition, the semiconductor substrate 3000 is
transported. By doing this, particles remain trapped between the
upper electrode 2200 and the grid 13 and fly toward the area
surrounding the plasma where they fall around the periphery
thereof, so that they do not fall onto the substrate.
[0231] (Twenty-Ninth Embodiment)
[0232] FIG. 35 shows the twenty-ninth embodiment of the present
invention.
[0233] In this embodiment, a plasma PZ is generated that is
sufficiently large with respect to the semiconductor substrate
3000. This plasma PZ is generated in accordance with the diameters
of the upper electrode 2200 and the lower electrode 2300 and, in
the case of FIG. 35, this is a plasma that is generated to
considerably outside the substrate 3000.
[0234] By doing this, so that the plasma PZ extends greatly beyond
the substrate 3000, particles drop along the outer periphery of the
plasma PZ, thereby preventing them from falling onto the substrate
3000.
[0235] (Thirtieth Embodiment)
[0236] FIG. 36 shows the thirtieth embodiment of the present
invention.
[0237] In this embodiment, a donut-shaped electrode 15 is installed
over the lower electrode 2300 so as to surround the substrate 3000,
a negative voltage being applied to the electrode 15.
[0238] The timing of the application of the above-noted voltage is
the time that the process is completed and the time that the plasma
power supply is turned off.
[0239] By doing the above, positively charged particles are guided
to the electrode 15, thereby preventing them from falling onto the
substrate 3000.
[0240] (Thirty-First Embodiment)
[0241] FIG. 37 shows the thirty-first embodiment of the present
invention.
[0242] In this embodiment, a laser apparatus is introduced for the
purpose of monitoring the generation of particles. The location at
which the laser light is shined is the region under the upper
electrode 2200. By adopting this configuration, it is possible'to
detect at an early stage particles that are trapped in the region
near the plasma sheath.
[0243] Then, after the-particles are detected, a negative voltage
is applied to the electrode 15, so as to collect the particles,
preventing them from falling onto the substrate 3000.
[0244] (Thirty-Second Embodiment)
[0245] FIG. 38 shows the thirty-second embodiment of the -present
invention.
[0246] In this embodiment, gate valves 17 are installed on the side
wall of the processing chamber near the upper electrode 2200, a
vacuum pump or other such exhausting apparatus being connected to
the outside thereof. An electrode 15 is installed in front of the
gate valve 17, and a provision is also made to apply a negative
voltage to this electrode 15.
[0247] When the processing is completed and the voltage applied to
the lower electrode 2300, is cut off, a negative voltage is applied
to the electrode 15. By doing this, particles are pulled toward the
gate valve 17. When this occurs, the gate valve 17 is opened, so
that the particles are exhausted, thereby preventing the particle
from falling onto the substrate 3000.
[0248] As described in detail above, the present invention is
capable of reducing the particles that become attached to a
substrate, and is an invention that is based on the charged
condition of the particles, enabling highly efficient prevention of
attachment of particles.
* * * * *