U.S. patent application number 09/735150 was filed with the patent office on 2001-06-28 for substrate processing apparatus and substrate processing method.
This patent application is currently assigned to TOKYO ELECTRON LIMITED OF JAPAN. Invention is credited to Kamikawa, Yuji, Kitahara, Shigenori, Ueno, Kinya.
Application Number | 20010004898 09/735150 |
Document ID | / |
Family ID | 18439899 |
Filed Date | 2001-06-28 |
United States Patent
Application |
20010004898 |
Kind Code |
A1 |
Kamikawa, Yuji ; et
al. |
June 28, 2001 |
Substrate processing apparatus and substrate processing method
Abstract
A substrate processing apparatus (1) for processing wafers (W)
has a first processing chamber (2) capable of containing the wafers
(W) and a second processing chamber (4) capable of containing the
wafers (W). The second processing chamber (4) is formed below and
near the first processing chamber (2) and is capable of
communicating with the first processing chamber (2). A wafer guide
(6) carries the wafers (W) vertically between the first and second
processing chambers (2, 4). A shutter (7) is opened to allow the
first and second processing chambers (2, 4) to communicate with
each other and is closed to isolate the same from each other. A
steam supply system (8) including steam supply port, an ozone gas
supply system (9) including ozone gas supply port and an IPA supply
system (10) including IPA supply port are combined with the first
processing chamber (2). A pure water supply system (11) including
pure water supply port and a draining unit (12) including a drain
pipe-line (141) through which pure water is drained are combined
with the second processing chamber (4).
Inventors: |
Kamikawa, Yuji; (Tosu-Shi,
JP) ; Kitahara, Shigenori; (Tosu-Shi, JP) ;
Ueno, Kinya; (Nirasaki-Shi, JP) |
Correspondence
Address: |
MORRISON & FOERSTER LLP
Suite 3500
555 West Fifth Street
Los Angeles
CA
90013-1024
US
|
Assignee: |
TOKYO ELECTRON LIMITED OF
JAPAN
|
Family ID: |
18439899 |
Appl. No.: |
09/735150 |
Filed: |
December 12, 2000 |
Current U.S.
Class: |
134/2 ; 134/21;
134/30; 134/61; 134/902; 134/95.2; 134/95.3; 438/689; 438/704;
438/706 |
Current CPC
Class: |
H01L 21/67028 20130101;
Y10S 134/902 20130101 |
Class at
Publication: |
134/2 ; 438/704;
438/706; 438/689; 134/21; 134/30; 134/61; 134/95.2; 134/95.3;
134/902 |
International
Class: |
B08B 003/02; H01L
021/302; H01L 021/461 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 14, 1999 |
JP |
1999-354785 |
Claims
What is claimed is:
1. A substrate processing apparatus for processing a substrate by a
plurality of processes, comprising: a first processing chamber for
containing the substrate; a second processing chamber for
containing the substrate, adjoining the first processing chamber
and capable of communicating with the first processing chamber; a
supporting member for supporting the substrate so as to carry the
substrate between the first processing chamber and the second
processing chamber; a solvent vapor supply port through which
solvent vapor is supplied into the first processing chamber; a
processing gas supply port through which a processing gas is
supplied into the first processing chamber; a drying gas supply
port through which a drying gas is supplied into the first
processing chamber; and a processing liquid supply port through
which a processing liquid is supplied into the second processing
chamber.
2. The substrate processing apparatus according to claim 1,
wherein: the solvent vapor supplied through the solvent vapor
supply port is a steam, the processing gas supplied through the
processing gas supply port is an ozone gas, the drying gas supplied
through the drying gas supply port is a gas containing IPA vapor,
and the processing liquid supplied through the processing liquid
supply port is a water.
3. The substrate processing apparatus according to claim 1, further
comprising: a vessel forming therein the first processing chamber
and the second processing chamber; and an exhaust pipe-line to
exhaust at least an atmosphere in the vessel.
4. The substrate processing apparatus according to claim 1, wherein
an inert gas pipe-line is connected to the processing gas supply
port so as to supply the inert gas from the processing gas supply
port into the first processing chamber.
5. The substrate processing apparatus according to claim 4, wherein
at least one of the solvent vapor, the processing gas and the
drying gas is purged from the first processing chamber by the inert
gas supplied through the inert gas pipe-line so that an atmosphere
in the first processing chamber is displaced.
6. The substrate processing apparatus according to claim 1, wherein
the second processing chamber is formed below the first processing
chamber.
7. The substrate processing apparatus according to claim 6, wherein
an exhaust pipe-line is connected to the first processing chamber
so as to exhaust the atmosphere in the first processing
chamber.
8. The substrate processing apparatus according to claim 7, wherein
a flow control valve is provided in the exhaust pipe-line so as to
control a flow rate of the atmosphere exhausted through the exhaust
pipe-line to regulate a pressure in the first processing
chamber.
9. The substrate processing apparatus according to claim 1, further
comprising a shutter disposed between the first processing chamber
and the second processing chamber, and capable of being opened and
closed.
10. The substrate processing apparatus according to claim 6,
further comprising a shutter disposed between the first processing
chamber and the second processing chamber and capable of being
opened and closed.
11. The substrate processing apparatus according to claim 1,
wherein a plurality of processing gas supply pipe-lines through
which different processing gases are supplied, respectively, are
connected to the processing gas supply port.
12. The substrate processing apparatus according to claim 11,
wherein an inert gas pipe-line is connected to the processing gas
supply port so as to supply the inert gas from the processing gas
supply port into the first processing chamber.
13. The substrate processing apparatus according to claim 1,
wherein a plurality of processing liquid supply pipe-lines through
which different processing liquids are supplied, respectively, are
connected to the processing liquid supply port.
14. The substrate processing apparatus according to claim 13,
further comprising a plurality of draining pipe-lines to drain
different processing liquids, respectively, from the second
processing chamber.
15. The substrate processing apparatus according to claim 1,
wherein a plurality of processing liquid supply pipe-lines through
which different processing liquids are supplied, respectively, are
connected to the processing liquid supply port.
16. The substrate processing apparatus according to claim 15,
further comprising a plurality of draining pipe-lines to drain
different processing liquids, respectively, from the second
processing chamber.
17. A substrate processing method for processing a substrate, on
which a resist film is formed, by a plurality of processes,
comprising the steps of: (a) carrying the substrate into a first
processing chamber for containing the substrate; (b) altering the
resist film on the substrate into a water-soluble film in the first
processing chamber; (c) carrying the substrate, on which the resist
film is altered, from the first processing chamber into a second
processing chamber for containing the substrate; (d) rinsing the
substrate with a water in the second processing chamber so that the
water-soluble film is removed from the substrate; (e) carrying the
rinsed substrate from the second processing chamber into the first
processing chamber; and (f) drying the rinsed substrate in the
first processing chamber.
18. The substrate processing method according to claim 17, wherein
the step of altering the resist film comprises supplying an ozone
gas and a water vapor into the first processing chamber.
19. The substrate processing method according to claim 18, wherein
the step of altering the resist film is carried out in a
pressurized atmosphere in the first processing chamber.
20. The substrate processing method according to claim 17, wherein
the first and second processing chambers are isolated by a shutter
while the step of altering the resist film and the step of drying
the rinsed substrate are carried out.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a substrate processing
apparatus and method for processing substrates, such as
semiconductor wafers by a plurality of processes including a
cleaning process and drying process.
[0003] 2. Description of the Related Art
[0004] A semiconductor device fabricating process employs a
processing apparatus that cleans substrates, such as semiconductor
wafers (hereinafter referred to simply as "wafers") to remove a
resist film formed on the wafers for a photolithographic process,
and contaminants adhering to the wafers, such as particles organic
substances and metallic impurities, from the wafers. Widely known
conventional processing apparatuses of this type are of batch
processing systems that clean and dry a plurality of wafers in a
batch.
[0005] Such a processing apparatus is provided with a wafer
processing unit, a rinsing unit and a wafer drying unit. The wafer
processing unit processes wafers by supplying process gases and
steam into a processing chamber. The rinsing unit immerses wafers
in pure water contained in a cleaning tank for rinsing (rinsing
process). The wafer drying unit dries wafers by supplying isopropyl
alcohol (hereinafter abbreviated to "IPA") into a drying chamber.
Processed wafers are subjected sequentially to a rinsing process
and a drying process.
[0006] An ozone-assisted process is carried out for altering resist
films formed on wafers by using, for example, ozone gas (O.sub.3
gas) and steam into water-soluble films that can be easily removed
from the wafers by a subsequent rinsing process. A hydrofluoric
acid cleaning process for removing an natural oxide film and
contaminants from wafers uses hydrofluoric acid vapor (HF vapor).
When carrying out a plurality of wafer processing processes by a
single wafer processing apparatus, a wafer processing unit and a
rinsing unit are used for each of the plurality of wafer processing
processes, and the plurality of wafer processing processes and
rinsing processes are carried out alternately.
[0007] However, since the conventional wafer processing apparatus
is provided with an individual wafer processing unit, an individual
rinsing unit and an individual wafer drying unit, the wafer
processing apparatus is large. When carrying out a plurality of
processes by a plurality of processing units included in a single
processing apparatus, the processing apparatus must be provided
with a plurality of wafer processing units and a plurality of
rinsing units. Consequently, the processing apparatus needs a large
floor space for installation. Wafers processed by a process using a
mixture of a processing gas and steam are carried to a rinsing
unit. While the wafers are being carried to the rinsing unit, the
wafers are exposed to the atmosphere, which is undesirably because
the exposure of the wafers to the atmosphere the possibility of
formation of a natural oxide film on the wafers. If carrying the
wafers to the rinsing unit takes a long time, reaction products
produced on the wafers by the process using the mixture of the
processing gas and steam and deteriorated films formed on the
wafers are changed into the different matters when the same are
exposed to the atmosphere. Consequently, it is possible that the
reaction products and films which are expected to be easily rinsed
off the wafers by a subsequent rinsing process are hardened or
become insoluble and remain as contaminants on the wafers.
SUMMARY OF THE INVENTION
[0008] Accordingly, it is an object of the present invention to
provide a substrate processing apparatus small in size and capable
of preventing exposure of processed substrates to the atmosphere
and to provide a substrate processing method in connection with the
apparatus.
[0009] To achieve the object, according to one aspect of the
present invention, there is provided a substrate processing
apparatus for processing a substrate by a plurality of processes,
comprising: a first processing chamber for containing a substrate;
a second processing chamber for containing the substrate, adjoining
the first processing chamber and capable of communicating with the
first processing chamber; a supporting member for supporting the
substrate so as to carry the substrate between the first processing
chamber and the second processing chamber; a solvent vapor supply
port through which solvent vapor is supplied into the first
processing chamber; a processing gas supply port through which a
processing gas is supplied into the first processing chamber; a
drying gas supply port through which a drying gas is supplied into
the first processing chamber; and a processing liquid supply port
through which a processing liquid is supplied into the second
processing chamber.
[0010] First, the substrate is placed in the first processing
chamber when processing the substrate by this substrate processing
apparatus. A solvent vapor is supplied through the solvent vapor
supply port into the first processing chamber and a processing gas
is supplied through the processing gas supply port into the first
processing chamber to process the substrate. After the substrate
has been processed, the supporting member carries the substrate
from the first processing chamber into the second processing
chamber. Then, a processing liquid is supplied through the
processing liquid supply port into the second processing chamber to
process the substrate with the processing liquid. Then, the
supporting member carries the substrate from the second processing
chamber into the first processing chamber. Then, a drying gas is
supplied through the drying gas supply port into the first
processing chamber to dry the substrate by a drying process.
[0011] Since the process using the processing gas and the solvent
vapor, the process using the processing liquid and the drying
process are carried out in the first and second processing chambers
adjoining each other and capable of communicating with each other,
the substrate processing apparatus can be formed in a small size.
Since the substrate are not taken out of the processing apparatus
during all the processes, the exposure of the substrate, which has
been processed by the process using the processing gas and the
solvent vapor, to the atmosphere can be prevented.
[0012] Since the first and second processing chambers adjoin each
other, the substrate can be quickly carried from the first
processing chamber to the second processing chamber, can be
processed with the processing liquid immediately after the process
using the processing gas and the solvent vapor, and can be
processed with the drying gas immediately after the process using
the processing liquid. Accordingly, the formation of the natural
oxide film on the substrate, and the change of reaction products
formed and altered on the substrate into different matters can be
prevented. Then, processes can be properly carried out and the
throughput of the processes can be improved.
[0013] Possible processing gases to be supplied through the
processing gas supply port include gases containing reactive
species (radicals, ions), such as ozone gas, chlorine gas fluorine
gas and the like.
[0014] For example, the solvent vapor supplied through the solvent
vapor supply port may be a steam, the processing gas supplied
through the processing gas supply port may be an ozone gas, the
drying gas supplied through the drying gas supply port may be a gas
containing IPA vapor, and the processing liquid supplied through
the processing liquid supply port may be a water.
[0015] The substrate processing apparatus may process the substrate
by an ozone-assisted process that supplies ozone gas through the
processing gas supply port into the first processing chamber
containing the substrate after supplying steam through the solvent
vapor supply port into the first processing chamber, carry the
substrate from the first processing chamber into the second
processing chamber by the supporting member, process the substrate
by a rinsing process by supplying water through the processing
liquid supply port into the second processing chamber, carry the
substrate from the second processing chamber into the first
processing chamber by the supporting member, and dry the substrate
by a drying process that supplies a gas containing IPA vapor
through the drying gas supply port into the first processing
chamber.
[0016] In the substrate processing apparatus, an inert gas
pipe-line may be connected to the processing gas supply port so as
to supply the inert gas from the processing gas supply port into
the first processing chamber.
[0017] Preferably, in this case, at least one of the solvent vapor,
the processing gas and the drying gas is purged from the first
processing chamber by the inert gas supplied through the inert gas
pipe-line so that an atmosphere in the first processing chamber is
displaced
[0018] In the substrate processing apparatus, the second processing
chamber may be formed below the first processing chamber.
[0019] Thus, the process using the processing gas and the solvent
vapor, the process using the liquid and the drying process can be
carried out by the substrate processing apparatus requiring a floor
space for one processing chamber.
[0020] Preferably, in this case, an exhaust pipe-line is connected
to the first processing chamber so as to exhaust the atmosphere in
the first processing chamber.
[0021] Preferably, in this case, a flow control valve is provided
in the exhaust pipe-line so as to control a flow rate of the
atmosphere exhausted through the exhaust pipe-line to regulate a
pressure in the first processing chamber.
[0022] Preferably, the substrate processing apparatus is provided
with a shutter disposed between the first processing chamber and
the second processing chamber and capable of being opened and
closed.
[0023] The diffusion of the atmosphere created in the first
processing chamber into the second processing chamber and the flow
of the liquid atmosphere created in the second processing chamber
into the first processing chamber can be prevented by closing the
shutter while processes are carried out in the first processing
chamber and second processing chambers.
[0024] Preferably, a plurality of processing gas supply pipelines
through which different processing gases are supplied,
respectively, are connected to the processing gas supply port.
[0025] Thus, a plurality of kinds of processes can be achieved by
individually using the different gases in combination with a
solvent vapor.
[0026] Preferably, a plurality of processing liquid supply
pipe-lines through which different processing liquids are supplied,
respectively, are connected to the processing liquid supply
port.
[0027] Thus, a plurality of kinds of processes can be achieved by
individually using the different processing liquids.
[0028] Preferably, in this case, the substrate processing apparatus
is provided with a plurality of draining pipe-lines to drain
different processing liquids, respectively, from the second
processing chamber.
[0029] According to another aspect of the present invention, there
is provided a substrate processing method for processing a
substrate, on which a resist film is formed, by a plurality of
processes, comprising the steps of: carrying the substrate into a
first processing chamber for containing the substrate; altering the
resist film on the substrate into a water-soluble film in the first
processing chamber; carrying the substrate, on which the resist
film is altered, from the first processing chamber into a second
processing chamber for containing the substrate; rinsing the
substrate with a water in the second processing chamber so that the
water-soluble film is removed from the substrate; carrying the
rinsed substrate from the second processing chamber into the first
processing chamber; and drying the rinsed substrate in the first
processing chamber.
[0030] The step of altering the resist film may comprise supplying
an ozone gas and a water vapor into the first processing
chamber.
[0031] Preferably, in this case, the step of altering the resist
film is carried out in a pressurized atmosphere in the first
processing chamber.
[0032] Preferably, the first and second processing chambers are
isolated by a shutter while the step of altering the resist film
and the step of drying the rinsed substrate are carried out.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a typical view of a substrate processing apparatus
in a first embodiment according to the present invention;
[0034] FIG. 2 is an enlarged typical view of a vessel and a
cleaning tank included in the substrate processing apparatus shown
in FIG. 1;
[0035] FIG. 3 is a perspective view of a wafer guide;
[0036] FIG. 4 is a perspective bottom view of a shutter;
[0037] FIG. 5 is a piping diagram of a steam supply system, an
ozone gas supply system, an IPA supply system and a pure water
supply system;
[0038] FIG. 6 is an enlarged piping diagram of an essential portion
of the steam supply system;
[0039] FIG. 7 is a side elevation of a steam supply member;
[0040] FIG. 8 is a flow chart of a substrate processing procedure
to be carried out by the substrate processing apparatus shown in
FIG. 1;
[0041] FIG. 9 is an enlarged typical view, similar to FIG. 2, of
the substrate processing apparatus when an exhaust pipe is provided
with a flow control valve;
[0042] FIG. 10 is a typical view of a substrate processing
apparatus in a second embodiment according to the present
invention; and
[0043] FIG. 11 is a diagram showing processes to be carried out in
step S3' instead of step S3 of the substrate processing procedure
shown in FIG. 8.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0044] Preferred embodiments of the present invention will be
described with reference to the accompanying drawings. The present
invention will be described as applied to substrate processing
apparatus that clean, for example, fifty-two wafers in a batch. The
substrate processing apparatus remove a resist from wafers by using
ozone gas.
First Embodiment
[0045] A substrate processing apparatus 1 in a first embodiment
according to the present invention will be described with reference
to FIGS. 1 to 9.
[0046] Referring to FIG. 1, the substrate processing apparatus 1
includes a vessel 3, a cleaning tank 5, a wafer guide 6, a shutter
7, a steam supply system 8, an ozone gas supply system 9, an IPA
supply system 10, a pure water supply system 11 and a draining unit
12. The vessel 3 defines a first processing chamber 2 capable of
containing fifty-two wafers W. The cleaning tank 5 disposed below
the vessel 3 defining the first processing chamber 2 defines a
second processing chamber 4 capable of containing fifty-two wafers
W. The wafer guide 6, served as a supporting member, is one of the
components of a supporting member for supporting the substrate so
as to carry wafers W between the first processing chamber 2 and the
second processing chamber 4. The a shutter 7 is disposed so as to
allow the first processing chamber 2 and the second processing
chamber 4 to communicate with each other and to isolate the first
processing chamber 2 and the second processing chamber 4 from each
other. The steam supply system 8, the ozone gas supply system 9 and
the IPA supply system 10 supply steam, i.e., a solvent vapor, ozone
gas (O.sub.3 gas), i.e., a processing gas, and IPA vapor, i.e., a
drying gas, respectively, into the first processing chamber 2. The
pure water supply system 11 supplies pure water, i.e., a processing
liquid, into the second processing chamber 4.
[0047] As shown in FIG. 2, the vessel 3 can be roughly divided into
a body 20 and a cover 21 capable of being joined to the body 20 so
as to cover the open upper end of the body 20 and of being removed
from the body 20 to open the open upper end of the body 20. The
open lower end of the vessel 3 opens into an open space 46 in a
passage unit 45. When the open upper end of the body 20 is covered
with the cover 21 as shown in FIG. 2, a lip O ring 23 is placed
between the body 20 and the cover 21 to prevent the leakage of an
atmosphere in the first processing chamber 2 outside the vessel
3.
[0048] A lamp heating unit 25 is attached to the outer surface of
the cover 21. The lamp heating unit 25 heats wafers W and an
atmosphere surrounding the wafers W at a predetermined temperature.
Exhaust boxes 26 are placed in the first processing chamber 2. The
atmosphere in the first processing chamber 2i is sucked into the
exhaust boxes 26 and is discharged outside. An exhaust pipe 27 has
one end connected to the exhaust boxes 26 and the other end
connected to a plant exhaust system. The cleaning tank 5 has an
inner tank 30 defining the second processing chamber 4, a middle
tank 31 joined to the inner tank 30 so as to surround the open
upper end of the inner tank 30, and an outer tank 32 joined to the
middle tank 31 so as to surround the open upper end of the middle
tank 31. The open upper end of the inner tank 30 opens into the
open space 46. The second processing chamber 4 is filled with a
processing liquid.
[0049] A drain pipe 33 for draining the processing liquid contained
in the second processing chamber 4 is connected to a central
portion of the bottom wall of the inner tank 30. The drain pipe 33
is provided with a shutoff valve 34. The processing liquid
overflowed the inner tank 30 is received by the middle tank 31 and
is drained through an overflow pipe 35 connected to the bottom of
the inner tank 30. The overflow pipe 35 is provided with a shutoff
valve 36. Pure water is contained always in the outer tank 32. An
annular sealing plate 37 is placed in the outer tank 32. The upper
end of the sealing plate 37 is in close contact with the bottom
surface of the passage unit 45. Thus, the outer tank 32 has a
water-sealing function using pure water to prevent the leakage of a
liquid atmosphere in the cleaning tank 5 outside the cleaning tank
5.
[0050] The wafer guide 6 is moved vertically, i.e., in the
directions of the arrows in FIG. 3, by a lifting mechanism, not
shown. The wafer guide 6 and the lifting mechanism constitute the
supporting member. As shown in FIG. 3, the wafer guide 6 includes a
guide member 40, and four parallel holding members 41a, 41b, 41c
and 41d fixedly attached to the guide member 40 in a horizontal
position. Each of the holding members 41a to 41d is provided with
fifty-two grooves 42 arranged at equal intervals. Lower portions of
peripheries of wafers W are received in the grooves 42. Fifty-two
wafers W can be held at equal intervals on the wafer guide 6. In
view of chemical resistance and hardness, it is preferable that
each of the guide member 40 and the holding members 41a to 41d is a
structure formed of PCTFE (polychlorotrifluoroetylene) and provided
with a core of a stainless steel.
[0051] As shown in FIGS. 2 and 4, the shutter 7 can be moved by a
driving mechanism, not shown, in vertical directions (directions of
the arrows Z in FIG. 4) and horizontal directions (directions of
the arrows X in FIG. 4). Sealing members 42 are placed on the upper
surface of the shutter 7. The shutter 7 is moved for opening and
closing operations in the passage unit 45. The passage unit 45 is
interposed between the vessel 3 and the cleaning tank 5. The
passage unit 45 has the open space 46 and a shutter receiving space
47. In FIG. 2, the shutter 7 indicated by continuous lines is moved
to the open space 46 by the driving mechanism, and the sealing
members 42 are in close contact with the inner surface of the top
wall of the passage unit 45 to isolate the atmosphere in the first
processing chamber 2 and the atmosphere in the second processing
chamber 4 from each other. In FIG. 2, the shutter 7 indicated by
two-dot chain lines 7' is moved to the shutter receiving space 47
by the driving mechanism to permit the first processing chamber 2
and the second processing chamber 4 to communicate with each
other.
[0052] The shutter 7 has a bottom wall divided into four sections
50a, 50b, 50c and 50d. The sections 50a to 50d are sloped down from
the periphery toward a central portion of the bottom wall. The
shutter 7 also has a top wall having substantially the same
configuration as the bottom wall. A drain pipe-line 56 is connected
to the central portion of the shutter 7. A draining member 51 is
disposed in the bottom of the shutter receiving space 47 of the
passage unit 45. A drain pipe 52 is connected to the draining
member 51. The drain pipe 52 is provided with a shutoff valve 53.
When the shutter 7 is closed, liquid drops formed on the bottom
wall of the shutter 7 by the condensation of the liquid atmosphere
in the cleaning tank 5 flow along the sections 50a to 50d of the
bottom wall and gather in a central portion of the bottom wall and
the gathered liquid drops are drained through a drain pipe-line 56
extended in the passage unit 45. Liquid drops formed on the top
wall of the shutter 7 by the condensation of the atmosphere in the
first processing chamber gather in the central portion of the
shutter 7 and the gathered liquid drops are drained by a pump 54.
When the shutter 7 wetted with liquid drops is opened, the liquid
drops fallen off the shutter 7 are drained through draining member
51 and the drain pipe 52.
[0053] N.sub.2 supply ports 55 are formed in opposite end portions
(right and left end portions as viewed in FIG. 2) of the bottom
wall 45a of the passage unit 45, respectively. N.sub.2 gas is
jetted through the N.sub.2 supply ports 55 to form an air curtain
over the second processing chamber 4. The atmospheres in the first
processing chamber 2 and the second processing chamber 4 can be
separated from each other by the air curtain.
[0054] Referring to FIGS. 5 and 6, the steam supply system 8 has a
pure water supply pipe-line 60 for supplying pure water, a steam
generating unit 61 that gasifies pure water supplied through the
pure water supply pipe-line 60 to generate steam, and a steam
supply pipe-line 62 through which steam generated by the steam
generating unit 61 is supplied. Water vapor supplied through the
steam supply pipe-line 62 is discharged through steam supply
members 63, each forming solvent vapor supply ports, into the first
processing chamber 2. The inlet end of the pure water supply
pipe-line 60 is connected to a pure water supply pipe-line 130
included in the pure water supply system 11, which will be
described later.
[0055] As shown in FIG. 6, the pure water supply pipe-line 60 is
provided with a flow controller 70 and a shutoff valve 71. The flow
controller 70 is connected to a controller 73. The steam generating
unit 61 has a cylinder 74. The pure water supply pipe-line 60 is
connected to an upper portion of the cylinder 74. A rubber heater
75 is applied to the side surface of the cylinder 74. A cartridge
heater 76 is inserted in the cylinder 74. The sensing head of a
temperature sensor 77 is inserted in the cylinder 74. The
temperature sensor 77 gives a signal indicating the temperature of
the interior of the cylinder 74 measured by the temperature sensor
77 to the controller 73 and the controller 73 monitors the
temperature of the interior of the cylinder 74. The temperature
sensor 77 is, for example, a K-type thermocouple. A pure water
draining pipe-line 78 is connected to the bottom wall of the
cylinder 74 to drain pure water that could not have been gasified
from the cylinder 74. The pure water draining pipe-line 78 is
provided with a flow control valve 79.
[0056] The rubber heater 75 is connected to the controller 73. The
controller 73 supplies power to the rubber heater 75 to heat the
interior of the cylinder 74. A temperature control sensor 80 and an
overheat sensor 81 are connected to the rubber heater 75 and the
controller 73. The controller 73 receives a signal indicating the
present temperature of the rubber heater 75 from the temperature
control sensor 80 to control the heating operation of the rubber
heater 75. The controller 73 receives a signal indicating the
temperature of the rubber heater 75 from the overheat sensor 81 and
monitors the temperature of the rubber heater 75 to prevent the
overheat of the rubber heater 75. The rubber heater 75 has a large
specific heating capacity, i.e., a large thermal output per unit
area. The temperature control sensor 80 and an overheat sensor 81
are, for example, K-type thermocouples. The rubber heater 75 is
lagged with an heat insulating material, not shown, to prevent the
thermal influence of the rubber heater 75 on surroundings. The heat
insulating material is a material capable of withstanding heat of
200.degree. C. or above, such as silicone rubber.
[0057] The cartridge heater 76 has a heating pipe 85 and a
plurality of disks 86 attached to the outer circumference of the
heating pipe 85. The cartridge heater 76 generates heat when power
is supplied thereto by the controller 73. A temperature control
sensor 87 and an overheat sensor 88 are connected to the cartridge
heater 76. The temperature control sensor 87 and the overheat
sensor 88 are connected to the controller 73. The heating operation
of the cartridge heater 76, similarly to that of the rubber heater
75, is controlled properly by the controller 73. Pure water
supplied through the pure water supply pipe-line 60 is dropped at a
low rate on the heated heating pipe 85 and the disks 86 to generate
steam. Flow of pure water, steam generating rate, and the density
and temperature of steam can be properly controlled by controlling
the opening of the flow controller 71. The steam generating unit 61
may be provided with a level gage pipe that enables the visual
observation of the level of pure water in the cylinder 74 to
monitor the level of pure water that has not been gasified and
remaining in the cylinder 74.
[0058] The steam supply pipe-line 62 is connected to an upper
portion of the cylinder 74 and is provided with a shutoff valve 90.
A plate heater 90 is combined with the shutoff valve 90. The
controller 73 supplies power to the plate heater 91 to make the
plate heater 91 generate heat. The maximum heating temperature
(effective temperature) of the plate heater 91 is, for example,
150.degree. C. A temperature control sensor 92 and an overheat
sensor 93 are attached to the plate heater 91. The respective
outputs of the temperature control sensor 92 and the overheat
sensor 93 are connected to the controller 73. The controller 73
controls the heating operation of the plate heater 91 properly.
[0059] A ribbon heater 95 is combined with the steam supply
pipe-line 62. The controller 73 supplies power to the ribbon heater
95 to make the ribbon heater 95 generate heat. The effective
temperature of the ribbon heater 95 is in the range of 90 to
120.degree. C. A temperature control sensor 96 and an overheat
sensor 97 are attached to the ribbon heater 95. The respective
outputs of the temperature control sensor 96 and the overheat
sensor 97 are connected to the controller 73. The controller 73
controls the heating operation of the ribbon heater 97 properly.
The plate heater 91 and the ribbon heater 95 heat steam flowing
through the steam supply pipe-line 62 to prevent the steam from
liquefying. A steam discharge pipe-line may be connected to the
steam supply pipe-line 62 to discharge steam through the steam
discharge pipe-line in an initial stage of steam generation until
the temperature of the cylinder 74 and steam generation in the
cylinder 74 are stabilized. A N.sub.2 supply pipe or an air supply
pipe may be connected to the cylinder 74 to send out steam from the
cylinder 74 by N.sub.2 gas or air.
[0060] As shown in FIG. 7 the steam supply member 63 has an inner
pipe 100 and an outer pipe 101 surrounding the inner pipe 100. The
inner pipe 100 is provided with, for example, five ports 102
arranged at equal intervals and a 0.8 mm diameter hole 103 formed
in an end portion thereof. The outer pipe 101 is provided with
fifty-two-six ports 104 arranged at equal intervals corresponding
to, for example, the pitches of 3.175 mm of wafers W held in the
first processing chamber 2 on one side thereof opposite the other
side thereof on the side of the ports 102. Each steam supply member
63 distributes steam supplied into the inner pipe 100 uniformly in
the outer pipe 101 to discharge the steam uniformly through the
ports 104.
[0061] As shown in FIG. 5, the ozone gas supply system 9 has a
branch pipe-line 110 branched from the pure water supply pipe-line
60, an ozone gas generator 111 that generates ozone gas, and an
ozone gas supply pipe-line 112 through which ozone gas generated by
the ozone gas generator 111 is supplied. Ozone gas supplied through
the ozone gas supply pipe-line 112 is discharged through ozone gas
supply members, each forming processing gas supply ports.
[0062] The ozone gas generator 111 is connected to the branch
pipe-line 110. The ozone gas generator 111 generates ozone gas
through the electrolysis of pure water supplied thereto through the
branch pipe-line 110. Desirably, ozone gas having an ozone
concentration of, for example, about 141 g/m.sup.3 (normal) (about
6.6% by volume) is generated and is supplied through the ozone gas
supply pipe-line 112 at a flow rate of about 50 l/min. The ozone
gas generator 111 may use oxygen gas (O.sub.2 gas) instead of pure
water and may generate ozone gas by passing oxygen gas through a
space between discharge electrodes. The ozone gas supply pipe-line
112 is provided with a shutoff valve 114. The ozone gas supply
members 113 are similar in construction to the steam supply members
63, and hence the description thereof will be omitted.
[0063] The IPA supply system 10 has an IPA vapor generating unit
120 that generates IPA vapor, and an IPA supply pipe-line 121
through which IPA vapor generated by the IPA vapor generating unit
120 is supplied. IPA vapor supplied through the IPA vapor supply
pipe-line 121 is discharged through IPA vapor supply members 122,
each forming drying gas supply ports, into the first processing
chamber 2. The IPA supply pipe-line 121 is provided with a shutoff
valve 123. The IPA vapor supply members 122 are similar in
construction to the steam supply members 63 and the ozone gas
supply members 113 and hence the description thereof will be
omitted. A N.sub.2 gas supply pipe may be connected to the IPA
vapor supply pipe-line 121, IPA vapor and N.sub.2 gas may be mixed
in the IPA vapor supply pipe-line 121 to produce a mixed gas, and
the mixed gas may be supplied to the IPA vapor supply members
122.
[0064] The pure water supply system 11 has the pure water supply
pipe-line 130 through which pure water (DIW) is supplied. Pure
water supplied through the pure water supply pipe-line 130 is
discharged through pure water supply members 131, each forming
processing liquid supply ports, into the second processing chamber
4. An inlet end of the pure water supply pipe-line 130 is connected
to a pure water source, not shown. The pure water supply pipe-line
130 is provided with a flow controller 132 and a shutoff valve
133.
[0065] Referring to FIGS. 1 and 2, the draining unit 12 has a box
140 containing the vessel 3 and the cleaning tank 5, and a drain
pipe-line 141 (FIG. 1) through which the processing liquid is
drained. As shown in FIG. 2, the drain pipe, 33, the overflow pipe
35, the drain pipe 52 and the drain pipe-line 56 are extended in
the box 140 and the respective outlets thereof are opened into the
box 140. The drain pipe-line 141 has one end connected to a bottom
portion of the box 140 and the other end connected to a drain
system of the plant. The drain pipe-line 141 is provided with a
shutoff valve 142. The shutoff valve 142 is opened to drain the
processing liquids drained through the drain pipes 33 and 52 and
the overflow pipe 35 into the box 140 through the drain pipe-line
141 to the drain system of the plant. An exhaust pipe-line 143 for
exhausting the box 140 is connected to the box 140. An atmosphere
around the vessel 3 and the cleaning tank 4 can be exhausted from
the box 140. Thus, the diffusion of the atmosphere in the first
processing chamber 2 and the liquid atmosphere in the cleaning tank
5 into the external space can be prevented, for example, when the
cover 21 is removed to carry wafers W into and out of the vessel
3.
[0066] Referring to FIGS. 1 and 5, a N.sub.2 gas supply pipe-line
150 for supplying N.sub.2 gas or hot N.sub.2 gas is connected to
the ozone gas supply pipe-line 112 of the ozone gas supply system
9. The inlet end of the N.sub.2 gas supply pipe-line 150 is
connected to a N.sub.2 gas source, not shown. The N.sub.2 gas
supply pipe-line 150 is provided with a heater 151 for heating
N.sub.2 gas and a shutoff valve 152. Thus, N.sub.2 gas or hot
N.sub.2 gas can be supplied to the ozone gas supply members 113.
When the shutoff valves 114 and 152 are opened and the heater 151
is energized, N.sub.2 gas of an ordinary temperature supplied from
the N.sub.2 gas source can be heated at a predetermined temperature
and hot N.sub.2 gas can be discharged through the ozone gas supply
members 113. Wafers W can be quickly heated at a predetermined
temperature or dried by blowing hot N.sub.2 gas directly against
the wafers W. When the heater 151 is not energized, N.sub.2 gas of
an ordinary temperature can be discharged for purging. For example,
N.sub.2 purging is carried out in a period between the time after
processed wafers W have been carried out of the vessel 3 and the
time before carrying wafers W to be processed into the vessel 3 to
purge the first processing chamber 2 of ozone gas and steam, i.e.,
to replace the atmosphere in the first processing chamber 3 with
N.sub.2 gas.
[0067] Hot air may be used instead of hot N.sub.2 gas for heating
wafers W. When hot air is used to heat wafers W, a hot air supply
pipe-line for supplying hot air and a purging N.sub.2 gas supply
pipe-line are extended individually. The hot air supply pipe-line
or the N2 gas supply pipe-line is connected selectively to the
ozone gas supply members 113; that is, the hot air supply pipe-line
is connected to the ozone gas supply members 113 when heating
wafers W, or the N2 gas supply pipe-line is connected to the ozone
gas supply members 113 when carrying out N.sub.2 purging.
[0068] The substrate processing apparatus 1 moves the wafer guide 6
vertically to place wafers W in the first processing chamber 2 or
the second processing chamber 4. In FIGS. 1 and 2, wafers W held on
the wafer guide 6 raised to an upper position in the first
processing chamber 2 are indicated by continuous lines, and wafers
held on the wafer guide 6 lowered to a lower position in the second
processing chamber 4 are indicated by two-dot chain line W'
[0069] In a state where wafers W are placed in the first processing
chamber 2, an ozone-assisted process can be achieved by supplying
ozone gas by the ozone gas supply system 9 and steam by the steam
supply system 8 into the first processing chamber 2, and a drying
process can be achieved by supplying IPA vapor by the IPA supply
system 10 into the first processing chamber 2. In a state where
wafers W are placed in the second processing chamber 4, a rinsing
process can be achieved by supplying pure water into the second
processing chamber 4 by the pure water supply system 11. Thus, the
substrate processing apparatus carries out continuously the
ozone-assisted process (a wafer processing process using steam as a
processing gas) and a subsequent rinsing process and a drying
process in a sealed space.
[0070] A cleaning method to be carried out by the substrate
processing apparatus 1 will be described with reference to a flow
chart shown in FIG. 8. The cover 21 is opened and, for example,
fifty-two wafers W provided with a resist film is carried into the
vessel 3 in step S1. The cover 21 is closed in step S2. The shutter
7 is closed and an air curtain is formed by discharging N.sub.2 gas
through the N.sub.2 ports 55 to isolate the atmosphere in the first
processing chamber 2 from that in the second processing chamber
4.
[0071] Subsequently, an ozone-assisted process is carried out in
the first processing chamber 2 in step S3. The lamp heating unit 25
is energized to generate heat, hot N.sub.2 gas is discharged
through the ozone gas supply members 113 to heat the wafers W at a
predetermined temperature. Preferably, the predetermined
temperature is lower than the dew point of steam supplied into the
first processing chamber 2 and in a temperature range that is
optimum for the process.
[0072] After heating the wafers W for a predetermined heating time,
the discharge of hot N.sub.2 gas is stopped and the steam supply
system 8 supplies steam into the first processing chamber 2. Since
the wafers W are heated at the temperature lower than the dew point
of the steam, the steam that comes into contact with the wafers W
condenses properly and thin pure water films can be formed on the
wafers W. Subsequently, the ozone gas supply system 9 supplies
ozone gas into the first processing chamber 2. Consequently, the
ozone gas dissolves in the thin pure water films to form
ozone-containing liquid films on the wafers W. The ozone-containing
liquid films contain a large amount of radicals of oxygen atoms,
hydrogen atoms and hydroxyl groups. The radicals do not become
extinct and cause an oxidizing reaction immediately to decompose
the resist forming the resist films into carboxylic acid, carbon
dioxide and water.
[0073] Thus, the resist films can be sufficiently oxidized and
decomposed and are altered into water-soluble films by the
ozone-containing liquid films. Since the wafers W are heated by
heat generated by the lamp heating unit 25 at temperatures in a
temperature range that ensures active oxidizing reaction, the
ozone-assisted process can be promoted. The water-soluble resist
films can be easily removed by the subsequent rinsing process.
[0074] The supply of steam and ozone gas is stopped to terminate
the ozone-assisted process. Subsequently, the rinsing process is
carried out in the second processing chamber 4 in step S4. Pure
water is supplied into the second processing chamber 4 through the
pure water supply members 131 of the pure water supply system 11.
After the second processing chamber 4 has been filled up with pure
water, the shutter 7 is opened, the wafer guide 6 is lowered to
carry the wafers W quickly into the second processing chamber 4 in
the substrate processing apparatus 1. Thus, the wafers W can be
immerse in the pure water in a short time without being exposed to
the external atmosphere for rinsing process. As mentioned above,
since the resist film is altered into the water-soluble films, the
resist films can be easily removed from the wafers W in the second
processing chamber 4.
[0075] During the rinsing process, new pure water is supplied
continuously by the pure water supply system 11, and the pure water
overflowed the inner tank 30 defining the second processing chamber
4 is received by the middle tank 31. Thus, pure water is supplied
during the rinsing process so as to overflow the inner tank 30 for
overflow rinsing. The valve 36 is opened to drain the overflowed
pure water through the overflow pipe 35 and the box 140 into a
draining unit 12. During the rinsing process, rising currents of
the pure water are produced in the second processing chamber 4.
Thus, the pure water can be uniformly applied to the wafers W for
uniform rinsing.
[0076] Then, the wafers W are subjected to a drying process in the
first processing chamber 2 in step S5. The wafer guide 6 is raided
to carry the wafers W quickly into the first processing chamber 2,
and then the shutter 7 is closed. IPA vapor or a mixture of IPA
vapor and N.sub.2 gas is supplied into the first processing chamber
2 by the IPA supply system 10. An IPA component, such as carbon,
remaining on the wafers W can be vaporized and removed from the
wafers W by blowing hot N.sub.2 gas through the ozone gas supply
members 113 against the wafers W after supplying IPA vapor or a
mixture of IPA vapor and N.sub.2 gas into the first processing
chamber 2. Hot N.sub.2 gas may be blown against the wafers W for
the drying process through the ozone gas supply members 113 of the
ozone gas supply system 9 instead of blowing IPA vapor or a mixture
of IPA vapor and N.sub.2 gas against the wafers W.
[0077] It is desirable to create an atmosphere of an ordinary
temperature in the first processing chamber 2 after the completion
of the drying process to provide a safe working environment by
supplying N.sub.2 gas of an ordinary temperature through the ozone
gas supply members 113 of the ozone gas supply system 9 into the
first processing chamber 2. It is preferable to supply IPA vapor or
a mixture of IPA vapor and N.sub.2 gas into the first processing
chamber 2 so as to fill up the first processing chamber 2 before
carrying the wafers W from the second processing chamber 4 into the
first processing chamber 2 because the IPA vapor or the mixture of
IPA vapor and N.sub.2 gas filling up the first processing chamber 2
promotes the drying process.
[0078] After the drying process has been completed, the cover 21 is
opened in step S6, and the wafers W are taken out of the vessel 3
and are carried away from the substrate processing apparatus 1 in
step S7. When the cover 21 is opened, the atmosphere surrounding
the vessel 3 and the cleaning tank 5 is exhausted from the box 140
to prevent the diffusion of the atmospheres in the first processing
chamber 2 and the second processing chamber 4. The first processing
chamber 2 is purged of the atmosphere by supplying N.sub.2 gas of
an ordinary temperature through the ozone gas supply members 113 of
the ozone gas supply system 9 into the first processing chamber 2
before receiving fifty-two wafers W to be processed by the next
processing cycle into the first processing chamber 2.
[0079] Since the second processing chamber 4 is formed below the
first processing chamber 2, the substrate processing apparatus 1 is
able to carry out the ozone-assisted process, the rinsing process
and the drying process continuously by using a floor space for one
processing chamber. Thus, the substrate processing apparatus can be
formed in a small size. Since the wafers W are not taken out of the
substrate processing apparatus 1 throughout a period between the
start of the ozone-assisted process and the completion of the
drying process, the exposure of the wafers W to air outside the
substrate processing apparatus after the ozone-assisted process can
be prevented.
[0080] Since the second processing chamber 4 is formed below the
first processing chamber 2, the wafers can be quickly moved in
vertical directions to start the rinsing process immediately after
the ozone-assisted process and to start the drying process
immediately after the rinsing process. Thus, it is possible for the
substrate processing apparatus to prevent the formation of a
natural oxide film on the wafer W and the alteration of the
water-soluble resist film formed by the alteration of the resist
film by the ozone-assisted process into an insoluble film by the
agency of air outside the substrate processing apparatus. It is
possible for the substrate processing apparatus to prevent the
alteration of various reactive reaction products produced on the
wafer W by the ozone-assisted process into other substances, such
as contaminants, by the agency of air outside the substrate
processing apparatus. Consequently, the rinsing process can be
properly carried out and the throughput of the substrate processing
apparatus can be enhanced.
[0081] When carrying out various processes in the first processing
chamber 2 and the second processing chamber 4, the shutter 7 can be
closed and an air curtain can be formed. Therefore, it is possible
to prevent the diffusion of the atmosphere in the first processing
chamber 2 into the second processing chamber 4 and the diffusion of
the liquid atmosphere in the second processing chamber 4 into the
first processing chamber 2.
[0082] Although the substrate processing apparatus in the first
embodiment discharges the atmosphere in the first processing
chamber 2 freely through the exhaust pipe 27 during the
ozone-assisted process, the exhaust pipe 27 may be provided with a
flow control mechanism as shown in FIG. 9 to control pressure in
the first processing chamber 2 optionally. As shown in FIG. 9, the
exhaust pipe 27 is provided with a flow control valve 155. The flow
control valve 155 is connected to the controller 73. Pressure in
the first processing chamber 2 is measured by a pressure sensor
156. The pressure sensor 156 is connected to the controller 73. The
controller 73 controls the opening of the flow control valve 155 on
the basis of a signal given thereto by the pressure sensor 156.
[0083] During the process, the opening of the flow control valve
155 of the exhaust pipe 27 is reduced to discharge the atmosphere
at a low rate so that a pressurized atmosphere of, for example, 196
kPa is created in the first processing chamber 2. Thus, the ozone
concentration of the atmosphere in the first processing chamber 2
can be increased. When forming a liquid film containing ozone on
the wafer W for processing by dissolving ozone gas in a pure water
film, an increased quantity of ozone gas can be dissolved in the
pure water film. Thus, a liquid film containing ozone in a very
high ozone concentration can be formed, which further enhances the
processing ability.
[0084] In the foregoing cleaning method supplies ozone gas after
supplying steam, steam and ozone gas may be simultaneously supplied
into the first processing chamber 2. When steam and ozone gas are
supplied simultaneously into the first processing chamber 2, the
steam and the ozone gas collide and mix to produce a mixed gas in
the first processing chamber 2. The mixed gas contains a large
amount of free radicals of oxygen and hydrogen. The radicals
reaching the wafer W cause an oxidizing reaction and, similarly to
the ozone-containing liquid film, decompose the resist forming the
resist films into carboxylic acid, carbon dioxide and water. Thus,
the resist film can be satisfactorily oxidized and decomposed into
water-soluble substances by the mixed gas of steam and ozone
gas.
[0085] The steam supply system 8 and the ozone gas supply system 9
are arranged individually to generate steam and ozone gas
individually and steam and ozone gas are supplied simultaneously.
Therefore, the mixed gas can be produced and radicals can be
produced in the first processing chamber 2. Consequently, the life
of the mixed gas of steam and ozone gas can be extended and the
mixed gas is able to reach the wafer W easily. The resist film
formed on the wafer W is altered into a water-soluble film not only
by the direct interaction of the mixed gas and the resist film but
by various modes and reactions in the first processing chamber 2.
For example, an ozone-containing liquid film is formed immediately
by condensing the mixed gas properly on the wafer W. This
ozone-containing film contains a large amount of reactive species
including radicals of oxygen and hydrogen and is capable of
satisfactorily oxidizing and decomposing the resist film to alter
the same into a water-soluble film.
[0086] Instead of carrying out the rinsing process by a dip
cleaning system that dips wafers W in pure water supplied through
the pure water supply members 131, the rinsing process may be
carried out by a shower cleaning system that jets pure water upward
and downward against wafers W through shower heads disposed in
upper and lower regions of the second processing chamber 4. The
pure water supply system 11 may be provided with both the pure
water supply members 131 and shower heads. When the pure water
supply system 11 is provided with both the pure water supply
members 131 and shower heads, the rinsing process can be carried
out by both the dip cleaning system and the shower cleaning system
in the second processing chamber 4.
Second Embodiment
[0087] A substrate processing apparatus 160 in the second
embodiment according to the present invention will be described
with reference to FIG. 10.
[0088] The substrate processing apparatus 160, differing from the
substrate processing apparatus 1 that carries out one kind of wafer
processing process using one kind of processing gas and steam and
one kind of liquid processing process using one kind of processing
liquid, is a multiple-purpose substrate processing apparatus that
carries out a plurality of kinds of wafer processing processes
using a plurality of kinds of processing gases and steam and
carries out a plurality of kinds of liquid processing
processes.
[0089] Referring to FIG. 10, the substrate processing apparatus 160
has a processing gas supply system 161 capable of supplying ozone
gas, hydrofluoric acid vapor (HF vapor) and chlorine gas (Cl.sub.2
gas) and a processing liquid supply system 162 capable of supplying
pure water, an ammonia solution (NH.sub.4OH), a hydrogen peroxide
solution (H.sub.2O.sub.2), hydrochloric acid and hydrofluoric acid.
The substrate processing apparatus 160 is provided with a draining
system 163 for draining APM, HPM and DHF in addition to pure water.
The substrate processing apparatus 160 is the same in construction
as the previously described substrate processing apparatus 1,
except that the former is provided with the processing gas supply
system 161, the processing liquid supply system 162 and the
draining system 163. Therefore, parts shown in FIG. 10 like or
corresponding to those of the substrate processing apparatus 1
shown in FIG. 1 are denoted by the same reference characters and
the description thereof will be omitted.
[0090] The processing gas supply system 161 has gas supply members,
each forming gas ports, and a gas supply pipe-line 164 connected to
the gas supply members 161. An ozone gas supply pipe-line 166, a
hydrofluoric acid vapor supply pipe-line 169 and a chlorine gas
supply pipe-line 172 are connected to the gas supply pipe-line 164.
The ozone gas supply pipe-line 166 is connected through the shutoff
valve 114 to the ozone gas generator 111. The hydrofluoric acid
vapor supply pipe-line 169 is connected through a shutoff valve 168
to a hydrofluoric acid vapor generating unit 167. The chlorine gas
supply pipe-line 172 is connected through a shutoff valve 171 to a
chlorine gas supply unit 170. A N2 gas supply pipe-line is
connected to the gas supply pipe-line 164 to carry out N.sub.2
purging by supplying N.sub.2 gas through the gas supply members
165.
[0091] The processing liquid supply system 162 has a processing
liquid supply pipe-line 175 connected to liquid supply members 176,
each forming liquid ports. A junction pipe 177 is connected to the
inlet end of the processing liquid supply pipe-line 175 to mix
different processing liquids therein. A pure water supply pipe-line
178, an ammonia solution supply pipe-line 183, a hydrogen peroxide
solution supply pipe-line 188, a hydrochloric acid supply pipe-line
193 and a hydrofluoric acid supply pipe-line 198 are connected to
the junction pipe 177. The pure water supply pipe-line 178 is
provided with the flow controller 132 and the shutoff valve 133.
The ammonia solution supply pipe-line 183 is connected through a
flow controller 181 and a shutoff valve 182 to an ammonia solution
supply unit 180. The hydrogen peroxide solution supply pipe-line
188 is connected through a flow controller 186 and a shutoff valve
187 to a hydrogen peroxide solution supply unit 185. The
hydrochloric acid supply pipeline 193 is connected through a flow
controller 191 and a shutoff valve 192 to a hydrochloric acid
supply unit 190. The hydrofluoric acid supply pipe-line 198 is
connected through a flow controller 196 and a shutoff valve 197 to
a hydrofluoric acid supply unit 195.
[0092] The APM (processing liquid) can be produced by properly
controlling the respective openings of the flow controllers 132,
181 and 186 to mix an ammonia solution, a hydrogen peroxide
solution and pure water in a predetermined mixing ratio in the
junction pipe 177. The HPM (processing liquid) can be produced by
properly controlling the respective openings of the flow
controllers 132, 186 and 191 to mix hydrochloric acid, a hydrogen
peroxide solution and pure water in a predetermined mixing ratio in
the junction pipe 177. The DHF (processing liquid) can be produced
by properly controlling the respective openings of the flow
controllers 186 and 196 to mix hydrofluoric acid and a hydrogen
peroxide solution in a predetermined mixing ratio in the junction
pipe 177. Chemical liquid cleaning processes, i.e., an SC1 cleaning
process using the APM (SC1 treatment), an SC2 cleaning process
using the HPM (SC2 treatment) and an HF cleaning process using the
DHF (HF treatment), can be carried out in the second processing
chamber 4. Only pure water is supplied into the second processing
chamber 4 to carry out a rinsing process (QDR rinsing) or the OF
rinsing process between different chemical liquid cleaning
processes.
[0093] The draining system 163 has an APM drain pipe-line 201, an
HPM drain pipe-line 203, a DHF drain pipe-line 205 and a pure water
drain pipe-line 207, which are connected to bottom portions of the
box 140. The APM drain pipe-line 201, the HPM drain pipe-line 203,
the DHF drain pipe-line 205 and the pure water drain pipe-line 207
are provided with shutoff valves 200, 202, 204 and 206,
respectively.
[0094] Basically, a cleaning method to be carried out by the
substrate processing apparatus 160 thus constructed is the same as
the cleaning method expressed by the flow chart shown in FIG. 8,
except that the cleaning method to be carried out by the substrate
processing apparatus 160 executes step S3' shown in FIG. 11 instead
of step S3 after carrying wafers W into the vessel 3 in step S1 and
closing the cover 21 in step S2. In the first processing chamber 2,
a hydrofluoric acid vapor cleaning process using hydrofluoric acid
vapor and steam (hydrofluoric acid treatment) and hydrochloric acid
cleaning process using hydrochloric acid gas and steam
(hydrochloric acid treatment) can be carried out in addition to an
ozone-assisted cleaning process using ozone.
[0095] When carrying out the hydrofluoric acid treatment in the
first processing chamber 2, steam is supplied first, and then
hydrofluoric acid vapor is supplied to form a hydrofluoric acid
solution film on wafers W. Natural oxide films formed on the wafers
W and particles adhering to the wafers W are removed from the
wafers W by the agency of radicals of fluorine atoms. Steam and
hydrofluoric acid vapor may be simultaneously supplied to use
radicals of fluorine atoms produced in a mixed gas of steam and
hydrofluoric acid vapor for removing natural oxide films and
particles from the wafers W. When carrying out the hydrochloric
acid treatment, steam is supplied first, and then hydrochloric acid
gas is supplied to form a hydrochloric acid solution film on the
wafers W. Natural oxide films formed on the wafers W and particles
adhering to the wafers W are removed from the wafers W by the
agency of radicals of hydrochloric acid. Steam and hydrochloric
acid vapor may be simultaneously supplied to use radicals of
hydrochloric acid produced in a mixed gas of steam and hydrochloric
acid vapor for removing natural oxide films and particles from the
wafers W.
[0096] The SC1 treatment, the SC2 treatment, the HF treatment and
the rinsing process can be carried out in the second processing
chamber 4. The SC1 treatment removes organic contaminants and
particles from wafers W by the agency of the APM. The SC2 treatment
removes metallic impurities from wafers W by the agency of the HPM.
The HF treatment removes natural oxide films and particles from
wafers W by the agency of the DHF.
[0097] In step S3', those processes can be selectively carried out
in a desired sequence. For example, the ozone-assisted process is
carried out in the first processing chamber 2 to alter resist films
into water-soluble films and the rinsing process is carried out in
the second processing chamber 4. Then, hydrofluoric acid treatment
is carried out in the first processing chamber 2 or the HF
treatment is carried out in the second processing chamber 4 to
clean the wafers W of impurities by etching the surfaces of wafers
W of silicon. Then, the rinsing process is carried out in the
second processing chamber 4 and, finally, a drying process is
carried out in the first processing chamber 2. The substrate
processing apparatus 160 can be used for specific wafer processing.
For example, the hydrofluoric acid treatment is carried out in the
first processing chamber 2, and then the rinsing process and the
drying process are carried out. It is possible to carry out the SC1
treatment, the rinsing process, the SC2 treatment, the rinsing
process, the HF treatment and the rinsing process successively in
the second processing chamber 4, and to carry out the drying
process finally in the first processing chamber 2.
[0098] The APM is drained through the APM drain pipe-line 201 after
the completion of the SC1 treatment, THE HPM is drained through the
HPM drain pipe-line 203 after the completion of the SC2 treatment,
and the DHF is drained through the DHF drain pipe-line 205 after
the completion of the HF treatment. Since the different processing
liquids are drained through the individual drain pipe-lines,
cross-contamination, i.e. the production of contaminants, such as
salts, by the mixing of, for example, an acidic substance and an
alkaline substance in a pipe forming the drain pipe-line can be
prevented.
[0099] The substrate processing apparatus 160 is capable of
carrying out a plurality of chemical liquid cleaning processes
(liquid treatments) and a plurality of vapor cleaning processes
(processes each using a processing gas and steam) in combination by
using a floor space for one processing chamber. Thus, the substrate
processing apparatus 160 is capable of further efficiently using
floor space. During the process, N.sub.2 gas can be continuously
supplied to carry out the processes properly in an N.sub.2
atmosphere. The substrate processing apparatus 160, similarly to
the substrate processing apparatus 1, is capable of preventing the
exposure of wafers to air outside the substrate processing
apparatus 160.
[0100] Although the invention has been described in its preferred
embodiments, the present invention is not limited thereto in its
practical application and various modifications are possible. It is
effective to activate an oxidizing reaction through the promotion
of the production of radicals of oxygen atoms in the liquid film by
supplying a small amount of a catalyst gas, such as NO.sub.x gas,
into the vessel 3.
[0101] The processing gas may be subjected to an excitation
reaction to make radicals grow. The cleaning process can be
promoted by supplying ozone gas containing radicals of oxygen
atoms, chlorine gas containing radicals of chlorine atoms and
fluorine gas containing radicals of fluorine atoms to produce an
increased quantity of radicals.
[0102] The present invention can be applicable not only to a
substrate processing apparatus that processes a plurality of
substrates in a batch but also to a substrate processing apparatus
that processes substrates one at a time. The substrates are not
limited to wafers W and may be CD substrates, printed wiring boards
and ceramic substrates.
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