U.S. patent application number 13/214881 was filed with the patent office on 2011-12-15 for substrate processing system, substrate processing method, and storage medium.
This patent application is currently assigned to TOKYO ELECTRON LIMITED. Invention is credited to Eiichi NISHIMURA.
Application Number | 20110303642 13/214881 |
Document ID | / |
Family ID | 39525415 |
Filed Date | 2011-12-15 |
United States Patent
Application |
20110303642 |
Kind Code |
A1 |
NISHIMURA; Eiichi |
December 15, 2011 |
SUBSTRATE PROCESSING SYSTEM, SUBSTRATE PROCESSING METHOD, AND
STORAGE MEDIUM
Abstract
A substrate processing system that can reliably prevent a rear
surface of a substrate from getting scratched without bringing
about a decrease in the throughput. A printing module connected to
a loader module prints a protective film on the rear surface of the
substrate before the substrate is subjected to plasma etching
processing. A cleaning module connected to the loader module
removes the protective film from the rear surface of the substrate
after the substrate has been subjected to the plasma etching
processing.
Inventors: |
NISHIMURA; Eiichi;
(Nirasaki-shi, JP) |
Assignee: |
TOKYO ELECTRON LIMITED
Tokyo
JP
|
Family ID: |
39525415 |
Appl. No.: |
13/214881 |
Filed: |
August 22, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11950832 |
Dec 5, 2007 |
|
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13214881 |
|
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60891911 |
Feb 27, 2007 |
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Current U.S.
Class: |
216/67 |
Current CPC
Class: |
H01L 21/6831 20130101;
H01L 21/67069 20130101; H01L 21/67051 20130101; H01L 21/0209
20130101 |
Class at
Publication: |
216/67 |
International
Class: |
C23F 1/00 20060101
C23F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 19, 2006 |
JP |
2006-341282 |
Claims
1. A substrate processing method in a substrate processing system
having at least an etching apparatus that subjects a substrate to
plasma etching processing, wherein the etching apparatus has a
mounting stage that electrostatically attracts and holds the
substrate, and the mounting stage contacts a rear surface of the
substrate, the substrate processing method comprising: a printing
step of printing a protective film on the rear surface of the
substrate; an etching step of subjecting a front surface of the
substrate to the plasma etching processing; and a removing step of
removing the protective film.
2. A substrate processing method as claimed in claim 1, wherein in
said printing step, the protective film is printed by carrying out
a screen printing process.
3. A substrate processing method as claimed in claim 1, wherein in
said printing step, the protective film is printed by attaching a
predetermined film.
4. A substrate processing method as claimed in claim 1, wherein in
said removing step, the protective film is removed by carrying out
a normal pressure plasma ashing process.
5. A substrate processing method as claimed in claim 1, wherein in
said removing step, the protective film is removed by carrying out
a superheated steam jetting process.
6. A substrate processing method as claimed in claim 1, wherein the
protective film is made of resin.
7. A substrate processing method as claimed in claim 1, wherein the
protective film is made of one selected from the following: silica,
organic polymer of fluorine-free aromatic hydrocarbon, polyimide,
and resist.
8. A substrate processing method as claimed in claim 1, wherein the
substrate processing system further comprises a protective film
removing apparatus that removes the protective film from the rear
surface of the substrate after the substrate has been subjected to
the plasma etching processing, wherein the protective film removing
apparatus includes a second mounting stage having a cylindrical
shape on which the substrate is mounted, and the second mounting
stage has on a top surface thereof jet holes, which jet protective
film removing agent, and lift pins projecting from the top surface,
and wherein in said removing step, the lift pins move the substrate
so that a gap between the protective film printed on the rear
surface of the substrate and each jet hole becomes 1 to 3 mm.
9. A substrate processing method as claimed in claim 1, wherein in
said removing step, if a portion of the protective film on a
contact area, where the substrate is in contact with the lift pin,
cannot be removed, a transfer arm mechanism which transfers the
substrate shifts the position of the substrate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 11/950,832, filed Dec. 5, 2007, the contents of which are
incorporated herein by reference, and is based upon and claims the
benefit of priority from U.S. Provisional Application No.
60/891,911, filed Feb. 27, 2007, and prior Japanese Patent
Application No. 2006-341282, filed Dec. 19, 2006.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a substrate processing
system, a substrate processing method, and a storage medium, and in
particular to a substrate processing system having an etching
apparatus that electrostatically attracts and holds a
substrate.
[0004] 2. Description of the Related Art
[0005] To form a wiring trench or a via hole with a desired pattern
on a surface of a wafer as a substrate using plasma, a photoresist
apparatus that forms a resist with a desired pattern on the surface
of the wafer, an etching apparatus that subjects the surface of the
wafer to etching processing such as RIE (Reactive Ion Etching), and
a cleaning apparatus that removes the resist are used. Here, the
photoresist apparatus has a coater that coats photosensitive resin
on a surface of a wafer, a stepper that exposes the photosensitive
resin to light, and a developer that removes the photosensitive
resin which has not yet hardened from the surface of the wafer. The
etching apparatus has a chamber in which the wafer is housed and
plasma is produced, and an electrostatic chuck that is disposed in
the chamber and electrostatically attracts and holds the wafer
while the wafer is subjected to the etching processing (see, for
example, Japanese Laid-Open Patent Publication (Kokai) No.
2005-347620).
[0006] The stepper irradiates a ray of ultraviolet light or the
like with a desired pattern onto the photosensitive resin on the
surface of the wafer. In recent years, due to miniaturization of
the desired pattern, a ray of ultraviolet light with a short
wavelength, for example, a wavelength of 193 nm has been used. When
the wavelength is short, the depth of focus is also small, and
hence the allowable flatness and inclination of the wafer are
small. Moreover, in the stepper, a plurality of pin-shaped
projections support the rear surface of the wafer, and hence
scratches, foreign matter, etc. on the rear surface of the wafer
greatly affect the flatness and inclination of the wafer.
[0007] Meanwhile, to realize complicated wiring structure and
electrode structure of a wafer for a semiconductor device, the
wafer is repeatedly subjected to etching by a substrate processing
system, and each time etching is carried out, the wafer is
electrostatically attracted to and held on the electrostatic chuck.
A surface of the electrostatic chuck is coated with yttria
(Y.sub.2O.sub.3), and hence a rear surface of the attracted wafer
made of silicon (Si) may get scratched. Also, the surface of the
electrostatic chuck may get scratched due to contact with the
attracted wafer. Then, foreign matter produced due to the scratched
surface of the electrostatic chuck may be transferred and attached
to the rear surface of the wafer.
[0008] Conventionally, foreign matter attached to a rear surface of
a wafer can be removed by wet cleaning using a cleaning solution or
the like, but there is unknown a method of effectively removing
scratches on the rear surface of the wafer. As a result, there is a
possibility that the allowable flatness and inclination of the
wafer will not be maintained due to scratches on the rear surface
of the wafer as described above. Therefore, it is necessary to
prevent the rear surface of the wafer from getting scratched when
the wafer is attracted to the electrostatic chuck.
[0009] For this reason, the present inventors have proposed a
substrate processing system that forms a protective film on a rear
surface of a wafer prior to etching processing by carrying out
deposition processing, i.e. CVD processing, or coating processing,
i.e. spin coat processing, and brings the protective film formed on
the rear surface of the wafer into contact with a surface of an
electrostatic chuck when the wafer is attracted to the
electrostatic chuck, so that the rear surface of the wafer can be
prevented from getting scratched.
[0010] However, in the above described CVD processing or spin coat
processing, a protective film is thinly formed on a rear surface of
a wafer, and when the wafer is repeatedly electrostatically
attracted to and held on the electrostatic chuck, the protective
film thinly formed on the rear surface of the wafer may be broken,
and as a result, the rear surface of the wafer may get
scratched.
[0011] Moreover, the above described wet cleaning and CVD
processing or spin coat processing has brought about a significant
decrease in the throughput of the substrate processing system.
SUMMARY OF THE INVENTION
[0012] The present invention provides a substrate processing
system, a substrate processing method, and a storage medium, which
can reliably prevent a rear surface of a substrate from getting
scratched without bringing about a decrease in the throughput.
[0013] Accordingly, in a first aspect of the present invention,
there is provided a substrate processing system having an etching
apparatus that subjects a substrate to plasma etching processing, a
vacuum substrate transfer apparatus having the etching apparatus
connected thereto, and an atmospheric substrate transfer apparatus
connected to the vacuum substrate transfer apparatus, wherein the
etching apparatus has a mounting stage that electrostatically
attracts and holds the substrate, and the mounting stage contacts a
rear surface of the substrate, the substrate processing system
comprising a protective film printing apparatus that is connected
to the atmospheric substrate transfer apparatus and prints a
protective film on the rear surface of the substrate before the
substrate is subjected to the plasma etching processing, and a
protective film removing apparatus that is connected to the
atmospheric substrate transfer apparatus and removes the protective
film from the rear surface of the substrate after the substrate has
been subjected to the plasma etching processing.
[0014] According to the first aspect of the present invention,
because a protective film is printed on a rear surface of a
substrate before the substrate is subjected to the plasma etching
processing, and the protective film is removed from the rear
surface of the substrate after the substrate has been subjected to
the plasma etching processing, the mounting stage contacts the
protective film thickly printed on the rear surface of the
substrate. Therefore, even when the substrate is repeatedly
attracted to and held on the mounting stage, the rear surface of
the substrate can be reliably prevented from getting scratched.
[0015] The present invention can provide a substrate processing
system, wherein the protective film printing apparatus prints the
protective film by carrying out a screen printing process.
[0016] According to the first aspect of the present invention,
because a protective film is printed by carrying out the screen
printing process, the protective film can be reliably thickly
printed. Further, because the screen printing process is carried
out at normal pressure, the throughput of the substrate processing
system is not significantly decreased.
[0017] The present invention can provide a substrate processing
system, wherein the protective film printing apparatus prints the
protective film by attaching a predetermined film.
[0018] According to the first aspect of the present invention,
because a protective film is printed by attaching a predetermined
film, the protective film can be reliably thickly printed. Further,
because the attachment of the predetermined film is carried out at
normal pressure, the throughput of the substrate processing system
is not significantly decreased.
[0019] The present invention can provide a substrate processing
system, wherein the protective film removing apparatus removes the
protective film by carrying out a normal pressure plasma ashing
process.
[0020] According to the first aspect of the present invention, a
protective film is removed by carrying out the normal pressure
plasma ashing process, the protective film can be reliably removed.
Further, because the normal pressure plasma ashing process is
carried out at normal pressure, the throughput of the substrate
processing system is not significantly decreased.
[0021] The present invention can provide a substrate processing
system, wherein the protective film removing apparatus removes the
protective film by carrying out a superheated steam jetting
process.
[0022] According to the first aspect of the present invention, a
protective film is removed by carrying out the superheated steam
jetting process, the protective film can be reliably removed.
Further, because the superheated steam jetting process is carried
out at normal pressure, the throughput of the substrate processing
system is not significantly decreased.
[0023] The present invention can provide a substrate processing
system, wherein the protective film is made of resin.
[0024] According to the first aspect of the present invention,
because a protective film is made of resin, the protective film can
be thickly printed with ease.
[0025] The present invention can provide a substrate processing
system, wherein the protective film is made of one selected from
the following: silica, organic polymer of fluorine-free aromatic
hydrocarbon, polyimide, and resist.
[0026] According to the first aspect of the present invention,
because a protective film is made of one selected from the
following: silica, organic polymer of fluorine-free aromatic
hydrocarbon, polyimide, and resist, the protective film can be
thickly printed with ease.
[0027] The present invention can provide a substrate processing
system, wherein in an upper portion of the mounting stage, a base
material of the mounting stage is exposed.
[0028] According to the first aspect of the present invention, in
the upper portion of the mounting stage, the base material of the
mounting stage is exposed. As a result, in a case where a substrate
having a rear surface with a protective film thickly printed
thereon is mounted on the upper surface of the mounting stage, the
substrate is mounted on the upper surface of the mounting stage
whose base material is exposed. Therefore, the substrate can be
attracted and held without disposing an electrostatic chuck in the
upper portion of the mounting stage, and hence the construction of
the mounting stage can be simplified.
[0029] The present invention can provide a substrate processing
system, wherein the protective film removing apparatus holds the
substrate without contacting the substrate.
[0030] According to the first aspect of the present invention, the
protective film removing apparatus holds the substrate without
contacting the substrate when a protective film is removed, the
protective film can be reliably removed, and a decrease in the
throughput of the substrate processing system can be reliably
prevented.
[0031] Accordingly, in a second aspect of the present invention,
there is provided a substrate processing method in a substrate
processing system having at least an etching apparatus that
subjects a substrate to plasma etching processing, wherein the
etching apparatus has a mounting stage that electrostatically
attracts and holds the substrate, and the mounting stage contacts a
rear surface of the substrate, the substrate processing method
comprising a printing step of printing a protective film on the
rear surface of the substrate, an etching step of subjecting a
front surface of the substrate to the plasma etching processing,
and a removing step of removing the protective film.
[0032] The present invention can provide a substrate processing
method, wherein in the printing step, the protective film is
printed by carrying out a screen printing process.
[0033] The present invention can provide a substrate processing
method, wherein in the printing step, the protective film is
printed by attaching a predetermined film.
[0034] The present invention can provide a substrate processing
method, wherein in the removing step, the protective film is
removed by carrying out a normal pressure plasma ashing
process.
[0035] The present invention can provide a substrate processing
method, wherein in the removing step, the protective film is
removed by carrying out a superheated steam jetting process.
[0036] The present invention can provide a substrate processing
method, wherein the protective film is made of resin.
[0037] The present invention can provide a substrate processing
method, wherein the protective film is made of one selected from
the following: silica, organic polymer of fluorine-free aromatic
hydrocarbon, polyimide, and resist.
[0038] The present invention can provide a substrate processing
method, wherein in the removing step, the substrate is held without
contact.
[0039] Accordingly, in a third aspect of the present invention,
there is provided a computer-readable storage medium storing a
program for causing a computer to execute a substrate processing
method in a substrate processing system having at least an etching
apparatus that subjects a substrate to plasma etching processing,
wherein the etching apparatus has a mounting stage that
electrostatically attracts and holds the substrate, and the
mounting stage contacts a rear surface of the substrate, the
substrate processing method comprising a printing step of printing
a protective film on the rear surface of the substrate, an etching
step of subjecting a front surface of the substrate to the plasma
etching processing, and a removing step of removing the protective
film.
[0040] The features, and advantages of the invention will become
more apparent from the following detailed description taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] FIG. 1 is a plan view schematically showing the construction
of a substrate processing system according to an embodiment of the
present invention;
[0042] FIG. 2 is sectional view schematically showing the
construction of a printing module appearing in FIG. 1;
[0043] FIG. 3 is sectional view schematically showing the
construction of a process module appearing in FIG. 1;
[0044] FIG. 4 is sectional view schematically showing the
construction of a cleaning module appearing in FIG. 1; and
[0045] FIG. 5 is a sectional view schematically showing a variation
of the cleaning module that removes a protective film from a rear
surface of a wafer.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0046] The present invention will now be described in detail below
with reference to the accompanying drawings showing a preferred
embodiment thereof.
[0047] First, a description will be given of a substrate processing
system according to an embodiment of the present invention.
[0048] FIG. 1 is a plan view schematically showing the construction
of a substrate processing system according to the embodiment.
[0049] As shown in FIG. 1, the substrate processing system 10 is
comprised of a transfer module 11 (vacuum substrate transfer
apparatus) that is hexagonal in plan view, four process modules 12
to 15 that are arranged in a radial pattern around the transfer
module 11 and subject wafers for semiconductor devices (hereinafter
referred to merely as "wafers") W (substrates) to predetermined
processing, a loader module 16 (atmospheric substrate transfer
apparatus) as a common rectangular transfer chamber, two load-lock
modules 17 and 18 that are disposed between the transfer module 11
and the loader module 16 and connect the transfer module 11 and the
loader module 16 together.
[0050] The interiors of the transfer module 11 and the process
modules 12 to 15 are maintained under vacuum, and the transfer
module 11 and the process modules 12 to 15 are connected together
via respective vacuum gate valves 19 to 22.
[0051] In the substrate processing system 10, the interior of the
loader module 16 is maintained at atmospheric pressure, while the
interior of the transfer module 11 is maintained under vacuum.
Thus, the load-lock modules 17 and 18 have vacuum gate valves 23
and 24, respectively, at joints to the transfer module 11, and have
atmospheric door valves 25 and 26, respectively, at joints to the
loader module 16, so that the load-lock modules 17 and 18 act as
vacuum auxiliary transfer chambers of which internal pressures are
controllable. The load-lock modules 17 and 18 also have wafer
mounting stages 27 and 28, respectively, on which wafers W
transferred between the loader module 16 and the transfer module 11
are temporarily mounted.
[0052] The transfer module 11 has therein a transfer arm 29 of a
frog leg type which is constructed such as to be able to bend,
extend and whirl about a pivot thereof, and the transfer arm 29
transfers wafers W between the process modules 12 to 15 and the
load-lock modules 17 and 18.
[0053] To the loader module 16 are connected three FOUP (Front
Opening Unified Pod) mounting stages 31 on which respective FOUPs
30 as containers each housing 25 wafers W are mounted, a printing
module 34 that prints a protective film, described later, on a rear
surface of a wafer W via a wafer inverting module 36 that inverts
the wafer W, and a cleaning module 35 that removes the protective
film from the rear surface of the wafer W, as well as the above
described load-lock modules 17 and 18.
[0054] The load-lock modules 17 and 18 are connected to a side wall
of the loader module 16 in the longitudinal direction thereof and
disposed such as to face the three FOUP mounting stages 31 across
the loader module 16. The printing module 34 is disposed at one end
of the loader module 16 as viewed in the longitudinal direction
thereof, and the cleaning module 35 is disposed at the other end of
the loader module 16 as viewed in the longitudinal direction
thereof.
[0055] The loader module 16 has therein a transfer arm mechanism 32
of a SCARA dual arm type for transferring wafers W, and three load
ports 33 through which wafers W are transferred and which are
disposed on a side wall of the loader module 16 such as to
correspond to the respective FOUP mounting stages 31. The transfer
arm mechanism 32 removes each wafer W from the FOUPs 30 mounted on
the FOUP mounting stages 31 via the load ports 33 and transfers the
removed wafer W into the printing module 34 and the cleaning module
35 via the load-lock module 17 and 18 and the wafer inverting
module 36.
[0056] In the substrate processing system 10, the printing module
34 (protective film printing apparatus) prints a protective film,
described later, on a rear surface of a wafer W, the process module
13 (etching apparatus) subjects the wafer W to the RIE processing,
and the cleaning module 35 (protective film removing apparatus)
removes the protective film printed on the rear surface of the
wafer W. In the substrate processing system 10, the wafer W is
sequentially transferred to the printing module 34, the process
module 13, and the cleaning module 35 in this order. It should be
noted that the wafer W is inverted by the wafer inverting module 36
before being transferred into the printing module 34.
[0057] FIG. 2 is sectional view schematically showing the
construction of the printing module 34 appearing in FIG. 1.
[0058] As shown in FIG. 2, the printing module 34 has a box-shaped
chamber 37 in which a wafer W is housed, a mounting stage 39 that
is disposed in a bottom portion 38 of the chamber 37, and a screen
printing unit 40 that is disposed at a predetermined distance from
the mounting stage 39 such as to face the mounting stage 39.
[0059] The mounting stage 39 is a cylindrical projection, and a
plurality of lift pins 41 are disposed on an upper surface of the
mounting stage 39. The top of each lift pin 41 has an oblique
surface, and the lift pins 41 contact a peripheral portion of a
surface of a wafer W transferred into the chamber 37 and support
the wafer W. The lift pins 41 are able to move the wafer W up and
down (vertically) as viewed in the drawing. When a wafer W is to be
transferred into and out from the chamber 37, the lift pins 41 move
the wafer W so that the wafer W can be positioned at the height of
a transfer port 47 for the wafers W, which is provided in a side
wall of the chamber 37.
[0060] The screen printing unit 40 has a screen film 43 on which a
print film 42 having the same shape as the rear surface of the
wafer W is formed, a frame 44 to which the screen film 43 is
attached in a stretched manner, and a spatula-shaped squeegee 45
disposed above the screen film 43.
[0061] The printing module 34 carries out a screen printing process
so as to print a protective film made of resin on the rear surface
of the wafer W. Specifically, first, the lift pins 41 move the
wafer W so that the rear surface of the wafer W can be positioned
at a predetermined height below the screen printing unit 40, and
then an insulating resin 46 is placed on the screen film 43. The
squeegee 45 is moved in the horizontal direction as viewed in the
drawing while the resin 46 is being pressurized against the screen
film 41, in particular, against the print film 42 by the squeegee
45, so that a protective film made of the resin 46 is printed on
the rear surface of the wafer W.
[0062] The printing module 34 prints a protective film with a
thickness of 30 to 50 .mu.m on the rear surface of the wafer W. It
should be noted that the resin 46 to be printed has only to be, for
example, polyimide. Also, the protective film to be printed is not
limited to being a protective film made of resin, but may be a
protective film made of silica (SiO.sub.2) or a resist, or a
protective film made of an organic polymer comprised of
fluorine-free aromatic hydrocarbon, i.e. a SILK (registered
trademark).
[0063] Although in the present embodiment, the protective film is
printed on the rear surface of the wafer W by carrying out the
screen printing process, the protective film may be printed on the
rear surface of the wafer W by carrying out a film attaching
process in which a resin film (predetermined film) produced in
advance such as to suit the shape of the rear surface of the wafer
W is attached to the rear surface of the wafer W.
[0064] The wafer W having the rear surface with the protective film
formed thereon by the printing module 34 is transferred out from
the chamber 37, then inverted by the wafer inverting module 36, and
further transferred by the loader module 16.
[0065] FIG. 3 is a sectional view schematically showing the
construction of the process module 13 appearing in FIG. 1.
[0066] As shown in FIG. 3, the process module 13 has a chamber 51
in which is housed a wafer W having a rear surface with a
protective film 48 formed thereon by the above described printing
module 34, and a cylindrical susceptor 52 as a mounting stage on
which the wafer W is mounted is disposed in the chamber 51.
[0067] In the process module 13, a side exhaust path 53 that acts
as a flow path through which gas above the susceptor 52 is
discharged to the outside of the chamber 51 is formed between the
inside wall of the chamber 51 and the side face of the susceptor
52. An exhaust plate 54 is disposed part way along the exhaust path
53.
[0068] The exhaust plate 54 is a plate-shaped member having a large
number of holes therein and acts as a partition plate that
partitions the chamber 51 into an upper part and a lower part
thereof. In the upper part 57 of the chamber 51 partitioned by the
exhaust plate 54, the susceptor 52 on which the wafer W is mounted
and other components are disposed, and plasma is produced. The
upper part of the chamber 51 will be hereinafter referred to as the
"reactive chamber." Moreover, a roughing exhaust pipe 55 and a main
exhaust pipe 56 through which gas in the chamber 51 is discharged
are provided opening out from the lower part (hereinafter referred
to as the "exhaust chamber (manifold)") 58 of the chamber 51. The
roughing exhaust pipe 55 has a DP (dry pump) (not shown) connected
thereto, and the main exhaust pipe 56 has a TMP (turbo-molecular
pump) (not shown) connected thereto. The exhaust plate 54 captures
or reflects ions and radicals, which are produced in a processing
space S, described later, of the reactive chamber 57, so as to
prevent the ions and the radicals from leaking into the manifold
58.
[0069] The roughing exhaust pipe 55, the main exhaust pipe 56, the
DP, the TMP, and so on constitute an exhausting apparatus, which
discharges gas in the reactive chamber 57 to the outside of the
chamber 51 via the manifold 58. Specifically, the roughing exhaust
pipe 55 reduces the pressure in the chamber 51 from atmospheric
pressure down to a low vacuum state, and the main exhaust pipe 56
is operated in collaboration with the roughing exhaust pipe 55 to
reduce the pressure in the chamber 51 from atmospheric pressure
down to a high vacuum state (e.g. a pressure of not more than 133
Pa (1 Torr)), which is at a lower pressure than the low vacuum
state.
[0070] A lower radio frequency power source 59 is connected to the
susceptor 52 via a matcher 60. The lower radio frequency power
source 59 supplies radio frequency electrical power of a
predetermined frequency to the susceptor 52. The susceptor 52 thus
acts as a lower electrode. The matcher 60 reduces reflection of the
radio frequency electrical power from the susceptor 52 so as to
maximize the efficiency of the supply of the radio frequency
electrical power into the susceptor 52.
[0071] In general, a disk-shaped electrostatic chuck made of an
insulating member, such as yttria, alumina (Al.sub.2O.sub.3), or
silica, having therein an electrode plate to which a DC power
source is electrically connected is provided in an upper portion of
the susceptor 52. When a wafer W is mounted on the susceptor 52,
the wafer W is disposed on the electrostatic chuck. Upon a negative
DC voltage being applied to the electrode plate, a potential
difference arises between the electrode plate and the rear surface
of the wafer W, and hence the wafer W is attracted to and held on
an upper surface of the electrostatic chuck through a Coulomb force
or a Johnsen-Rahbek force due to the potential difference. On the
other hand, in the present embodiment, the base material of the
susceptor 52, such as aluminum, is exposed in the upper portion of
the susceptor 52.
[0072] In the present embodiment, because the protective film 48
made of an insulating resin with a thickness of 30 to 50 .mu.m is
printed on the rear surface of the wafer W, the wafer W can be
attracted to and held on the upper surface of the susceptor 52 in a
state with the base material of the susceptor 52 being exposed
without disposing the above-mentioned electrostatic chuck in the
upper portion of the susceptor 52. Specifically, a DC power source
61 is electrically connected to the susceptor 52. Upon a negative
DC voltage being applied to the susceptor 52, a positive potential
is produced at a boundary between the wafer W and the protective
film 48, and a negative potential is produced on a front surface of
the wafer W. A potential difference thus arises between the upper
surface of the susceptor 52 and the boundary between the wafer W
and the protective film 48, and hence the wafer W is attracted to
and held on the upper surface of the susceptor 52 through a Coulomb
force or a Johnsen-Rahbek force due to the potential difference. It
should be noted that in the present embodiment, the electrostatic
chuck may be disposed in the upper portion of the susceptor 52.
[0073] An annular focus ring 62 is provided on an upper portion of
the susceptor 52 so as to surround the wafer W attracted to and
held on the upper surface of the susceptor 52. The focus ring 62 is
exposed to the processing space S and focuses plasma in the
processing space S toward the front surface of the wafer W, thus
improving the efficiency of the RIE processing.
[0074] An annular coolant chamber 63 that extends, for example, in
a circumferential direction of the susceptor 52 is provided inside
the susceptor 52. A coolant, for example cooling water or a Galden
(registered trademark) fluid, at a predetermined temperature is
circulated through the coolant chamber 63 via coolant piping 64
from a chiller unit (not shown). The processing temperature of the
wafer W attracted to and held on the upper surface of the susceptor
52 is controlled through the temperature of the coolant.
[0075] A plurality of heat transfer gas supply holes 65 are
provided in a portion of the upper surface of the susceptor 52 on
which the wafer W is attracted and held (hereinafter referred to as
the "attracting surface"). The heat transfer gas supply holes 65
are connected to a heat transfer gas supply unit (not shown) via a
heat transfer gas supply line 66. The heat transfer gas supply unit
supplies helium gas as a heat transfer gas via the heat transfer
gas supply holes 65 into a gap between the attracting surface of
the susceptor 52 and the rear surface of the wafer W. The helium
gas supplied into the gap between the attracting surface of the
susceptor 52 and the rear surface of the wafer W transfers heat of
the wafer W to the susceptor 52.
[0076] A plurality of pusher pins (not shown) are provided in the
attracting surface of the susceptor 52 as lifting pins that can be
made to project out from the attracting surface of the susceptor
52. The pusher pins are connected to a motor (not shown) by a ball
screw (not shown) and can be made to project out from the
attracting surface of the susceptor 52 through rotational motion of
the motor, which is converted into linear motion by the ball screw.
The pusher pins are housed inside the susceptor 52 when a wafer W
is being attracted to and held on the attracting surface of the
susceptor 52 so that the wafer W can be subjected to the RIE
processing, and are made to project out from the upper surface of
the susceptor 52 so as to lift the wafer W up away from the
susceptor 52 when the wafer W is to be transferred out from the
chamber 51 after having been subjected to the RIE processing.
[0077] A gas introducing shower head 67 is disposed in a ceiling
portion of the chamber 51 (reactive chamber 57) so as to face the
susceptor 52. An upper radio frequency power source 69 is connected
to the gas introducing shower head 67 via a matcher 68, and the
upper radio frequency power source 69 supplies radio frequency
electrical power of a predetermined frequency into the gas
introducing shower head 67. The gas introducing shower head 67 thus
acts as an upper electrode. It should be noted that the matcher 68
has a similar function to the matcher 60.
[0078] The gas introducing shower head 67 has a ceiling electrode
plate 71 having a number of gas holes 70 therein, and an electrode
support 72 that detachably supports the ceiling electrode plate 71.
A buffer chamber 73 is provided inside the electrode support 72,
and a processing gas introducing pipe 74 is connected to the buffer
chamber 73. A processing gas supplied from the processing gas
introducing pipe 74 into the buffer chamber 73 is supplied by the
gas introducing shower head 67 into the chamber 51 (reactive
chamber 57) via the gas holes 70.
[0079] A transfer port 75 for the wafers W is provided in a side
wall of the chamber 51 in a position at the height of a wafer W
that has been lifted up from the susceptor 52 by the pusher pins.
The vacuum gate valve 20 for opening and closing the transfer port
75 is provided in the transfer port 75.
[0080] In the chamber 51 of the process module 13, radio frequency
electrical power is supplied into the susceptor 52 and the gas
introducing shower head 67, and thus the radio frequency electrical
power is applied to the processing space S between the susceptor 52
and the gas introducing shower head 67 as described above, whereby
the processing gas supplied into the processing space S from the
gas introducing shower head 67 is turned into high-density plasma,
so that ions and radicals are produced. The wafer W is subjected to
the RIE processing by the ions and radicals.
[0081] FIG. 4 is sectional view schematically showing the
construction of the cleaning module 35 appearing in FIG. 1.
[0082] As shown in FIG. 4, the cleaning module 35 has a chamber 81
as a box-shaped container housing a wafer W having a rear surface
on which the protective film 48 described above has been printed
and a front surface which has been subjected to the RIE processing
described above, a mounting stage 83 that is disposed in a bottom
portion 82 of the chamber 81, and an exhaust pipe 84 that
discharges gas and the like in the chamber 81 to the outside.
[0083] The mounting stage 83 is a cylindrical projection and has
therein a normal pressure plasma producing unit (not shown) that
turns a processing gas supplied at normal pressure into plasma to
produce ions and radicals, and has an upper surface in which are
formed a plurality of jet holes 85 from which the ions and radicals
produced by the normal pressure plasma producing unit are jetted. A
plurality of lift pins 86 are disposed on an upper surface of the
mounting stage 83. The top of each lift pin 86 is conical, and the
lift pins 86 contact the protective film 48 printed on a rear
surface of a wafer W transferred into the chamber 81 and support
the wafer W. The lift pins 86 can move the wafer W vertically as
viewed in the drawing. To remove the protective film 48 printed on
the rear surface of the wafer W, the lift pins 86 move the wafer W
so that the gap between the protective film 48 printed on the rear
surface of the wafer W and each jet hole 85 can be 1 to 3 mm, and
when the wafer W is to be transferred into and out from the chamber
81, the lift pins 86 move the wafer W so that the wafer W can be
positioned at the height of a transfer port 87 for the wafers W,
which is provided in a side wall of the chamber 81.
[0084] In the cleaning module 35, ions and the like are jetted from
the jet holes 85 toward the protective film 48 printed on the rear
surface of the wafer W supported by the lift pins 86. The ions and
the like jetted from the jet holes 85 decompose and remove the
protective film 48 (normal pressure plasma aching process). It
should be noted that areas of contact of the protective film 48
with the lift pins 86 cannot be decomposed and removed because
contact of the ions and the like is obstructed by the lift pins 86.
Therefore, the transfer arm mechanism 32 shifts the position of the
wafer W to bring the wafer W into contact with the lift pins 86
again, so that the protective film in the areas of contact is
decomposed and removed in the same manner.
[0085] Although in the present embodiment, the mounting stage 83
has therein the normal pressure plasma producing unit, and ions and
the like produced by the normal pressure plasma producing unit are
jetted from the plurality of jet holes 85 so that the protective
film 48 can be decomposed and removed by the ions and the like,
this is not limitative, but rather the mounting stage 83 may have a
superheated steam producing unit that produces superheated steam in
the mounting stage 83, and the superheated steam produced by the
superheated steam producing unit may be jetted from the plurality
of jet holes 85 so that the protective film 48 can be removed by
the superheated steam (superheated steam jetting process). Here,
superheated steam with a temperature of not less than 120.degree.
C. is used.
[0086] Moreover, in the present embodiment, at least one suction
port for sucking ions and the like and superheated steam and the
like jetted from the jet holes 85 may be provided in the upper
surface of the mounting stage 83.
[0087] Referring again to FIG. 1, the substrate processing system
10 has a system controller (not shown) that controls operation of
the component elements, for example, the transfer module 11, the
process modules 12 to 15, and the loader module 16, and an
operation panel 90 disposed at one end of the loader module 16 as
viewed in the longitudinal direction thereof.
[0088] The operation panel 90 has a display unit comprised of, for
example, an LCD (liquid crystal display), and the display unit
displays operating states of the component elements of the
substrate processing system 10.
[0089] According to the substrate processing system 10 described
above, the protective film 48 with a thickness of 30 to 50 .mu.m is
printed on the rear surface of the wafer W before the wafer W is
subjected to the RIE processing, and the protective film 48 is
removed from the rear surface of the wafer W by the normal pressure
plasma ashing process after the wafer W has been subjected to the
RIE processing, and hence the protective film 48 can be thickly
printed on the rear surface of the wafer W, and also the protective
film 48 can be reliably removed. Moreover, in the process module
13, the susceptor 52 contacts the thick protective film 48 printed
on the rear surface of the wafer W. Thus, even when the wafer W is
being repeatedly attracted to and held on the susceptor 52
electrostatically, the rear surface of the wafer W and the upper
surface of the susceptor 52 can be reliably prevented from getting
scratched, and the degree of adhesion between the wafer W and the
susceptor 52 is increased, so that the temperature of the wafer W
can be controlled in a more reliably manner. Moreover, the wafer W
can be attracted to and held on the upper surface of the susceptor
52 in a state with the base material of the susceptor 52 being
exposed without disposing the electrostatic chuck in the upper
portion of the susceptor 52, and hence the construction of the
susceptor 52 can be simplified.
[0090] In the substrate processing system 10, because the printing
module 34 prints the protective film 48 by carrying out the screen
printing process, the printing module 34 is an atmospheric
processing apparatus. Therefore, the protective film 48 can be
printed on the rear surface of the wafer W at normal pressure, and
hence the throughput of the substrate processing system 10 is not
significantly decreased. Moreover, because the loader module 16 is
an atmospheric substrate transfer apparatus, the printing module 34
can be easily connected to the loader module 16. Therefore, it is
not necessary to make substantial changes to the construction of a
conventional substrate processing system for the connecting
printing module 34 to the loader module 16.
[0091] Moreover, in the substrate processing system 10, because the
cleaning module 35 removes the protective film 48 by carrying out
the normal pressure plasma ashing process, the cleaning module 35
is an atmospheric processing apparatus. Therefore, the protective
film 48 can be removed from the rear surface of the wafer W at
normal pressure, and hence the throughput of the substrate
processing system 10 is not significantly decreased. Moreover,
because the loader module 16 is an atmospheric substrate transfer
apparatus, the cleaning module 35 can be easily connected to the
loader module 16. Therefore, it is not necessary to make
substantial changes to the construction of a conventional substrate
processing system for connecting the cleaning module 35 to the
loader module 16.
[0092] Next, a description will be given of a variation of the
above described cleaning module that removes the protective film
from the rear surface of the wafer W.
[0093] The present variation is basically the same as the cleaning
module 35 described above in terms of construction and operation,
differing from the cleaning module 35 in the way of holding the
wafer W. Features of the construction and operation that are the
same as those of the cleaning module 35 will thus not be described,
only features that are different from those of the cleaning module
35 being described below.
[0094] FIG. 5 is a sectional view schematically showing the
construction of the variation of the cleaning module that removes
the protective film from the rear surface of the wafer W.
[0095] As shown in FIG. 5, the cleaning module 91 has a Bernoulli
chuck unit 92 provided above the mounting stage 83. The Bernoulli
chuck unit 92 has a gas introducing pipe 93, and a nozzle 94 that
is connected to the gas introducing pipe 93, broadens toward the
end, and has an outer end thereof bending inward.
[0096] As shown in FIG. 5, the Bernoulli chuck unit 92 introduces a
predetermined gas from the gas introducing pipe 93 into the nozzle
94, which then supplies the introduced gas toward the wafer W from
the front surface side thereof. Then, the gas introduced from the
front surface side of the wafer W passes to the rear surface side
of the wafer W, and the wafer W is caused to float due to a gas
pressure difference produced between the front surface side and the
rear surface side of the wafer W, so that the wafer W can be
suspended without contacting not only the Bernoulli chuck unit 92
but also the mounting stage 83.
[0097] In the cleaning module 91, the normal pressure plasma ashing
process or the superheated steam jetting process is carried out on
the protective film 48 printed on the rear surface of the wafer W,
which is suspended without contacting not only the Bernoulli chuck
unit 92 but also the mounting stage 83, so as to remove the
protective film 48 from the rear surface of the wafer W.
[0098] According to the present variation, because the protective
film 48 is removed from the rear surface of the wafer W, which is
suspended without contacting not only the Bernoulli chuck unit 92
but also the mounting stage 83, by carrying out the normal pressure
plasma ashing process or the superheated steam jetting process, the
protective film 48 can be reliably removed from the rear surface of
the wafer W. Therefore, it is unnecessary to shift the position of
the wafer W and carry out the normal pressure ashing process or the
superheated steam jetting process again as in the case of the above
described cleaning module 35, and hence a decrease in the
throughput of the substrate processing system 10 can be reliably
prevented.
[0099] Further, the substrates subjected to the etching processing
in the substrate processing system according to the present
embodiment are not limited to being semiconductor wafers, but
rather may instead be any of various substrates used in LCDs
(Liquid Crystal Displays), FPDs (Flat Panel Displays) or the like,
photomasks, CD substrates, printed substrates, or the like.
[0100] It is to be understood that the object of the present
invention may also be accomplished by supplying a system or an
apparatus with a storage medium in which a program code of
software, which realizes the functions of the above described
embodiment is stored, and causing a computer (or CPU or MPU) of the
system or apparatus to read out and execute the program code stored
in the storage medium.
[0101] In this case, the program code itself read from the storage
medium realizes the functions of the above described embodiment,
and hence the program code and a storage medium on which the
program code is stored constitute the present invention.
[0102] Examples of the storage medium for supplying the program
code include a floppy (registered trademark) disk, a hard disk, a
magnetic-optical disk, an optical disk such as a CD-ROM, a CD-R, a
CD-RW, a DVD-ROM, a DVD-RAM, a DVD-RW, and a DVD+RW, a magnetic
tape, a nonvolatile memory card, and a ROM. Alternatively, the
program code may be downloaded via a network.
[0103] Further, it is to be understood that the functions of the
above described embodiment may be accomplished not only by
executing a program code read out by a computer, but also by
causing an OS (operating system) or the like which operates on the
computer to perform a part or all of the actual operations based on
instructions of the program code.
[0104] Further, it is to be understood that the functions of the
above described embodiment may be accomplished by writing a program
code read out from the storage medium into a memory provided in an
expansion board inserted into a computer or a memory provided in an
expansion unit connected to the computer and then causing a CPU or
the like provided in the expansion board or the expansion unit to
perform a part or all of the actual operations based on
instructions of the program code.
* * * * *