U.S. patent application number 14/142507 was filed with the patent office on 2014-04-24 for substrate treating apparatus.
This patent application is currently assigned to Dainippon Screen MFG. Co., Ltd.. The applicant listed for this patent is Dainippon Screen MFG. Co., Ltd.. Invention is credited to Tomoaki AIHARA.
Application Number | 20140109430 14/142507 |
Document ID | / |
Family ID | 40786942 |
Filed Date | 2014-04-24 |
United States Patent
Application |
20140109430 |
Kind Code |
A1 |
AIHARA; Tomoaki |
April 24, 2014 |
SUBSTRATE TREATING APPARATUS
Abstract
A substrate treating apparatus for drying substrates with a
solvent vapor after treating the substrates with a treating liquid.
The apparatus includes a treating tank for storing the treating
liquid, a holder for holding the substrates in the treating tank, a
chamber enclosing the treating tank, a solvent vapor supply device
for supplying the solvent vapor into the chamber, an exhaust device
for exhausting gas from the chamber through an exhaust pipe
connected at one end thereof to the chamber, a drain pipe connected
at one end thereof to the chamber for draining the treating liquid
from the chamber, a gas-liquid separator having the other end of
the exhaust pipe connected thereto for receiving the gas exhausted
by the exhaust device, and having the other end of the drain pipe
connected thereto for receiving the treating liquid drained through
the drain pipe, the gas-liquid separator separating the gas and the
liquid, and a mixer mounted on the exhaust pipe for mixing
deionized water into the gas exhausted by the exhaust device.
Inventors: |
AIHARA; Tomoaki; (Kyoto,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dainippon Screen MFG. Co., Ltd. |
Kyoto |
|
JP |
|
|
Assignee: |
Dainippon Screen MFG. Co.,
Ltd.
Kyoto
JP
|
Family ID: |
40786942 |
Appl. No.: |
14/142507 |
Filed: |
December 27, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12340235 |
Dec 19, 2008 |
8640359 |
|
|
14142507 |
|
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|
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Current U.S.
Class: |
34/201 |
Current CPC
Class: |
B01D 2258/0216 20130101;
H01L 21/02041 20130101; H01L 21/67028 20130101 |
Class at
Publication: |
34/201 |
International
Class: |
H01L 21/02 20060101
H01L021/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 2007 |
JP |
2007-328927 |
Jul 29, 2008 |
JP |
2008-194789 |
Claims
1. A substrate treating apparatus for drying substrates with a
solvent vapor after treating the substrates with a treating liquid,
said apparatus comprising: a treating tank for storing the treating
liquid; a holding device for holding the substrates in the treating
tank; a chamber enclosing the treating tank; a solvent vapor supply
device for supplying the solvent vapor into the chamber; an exhaust
device for exhausting gas from the chamber through an exhaust pipe
connected at one end thereof to the chamber; a drain pipe connected
at one end thereof to the chamber for draining the treating liquid
from the chamber; a gas-liquid separating device having the other
end of the exhaust pipe connected thereto for receiving the gas
exhausted by the exhaust device, and having the other end of the
drain pipe connected thereto for receiving the treating liquid
drained through the drain pipe, the gas-liquid separating device
separating the gas and the liquid; and a mixing device mounted on
the exhaust pipe for mixing deionized water into the gas exhausted
by the exhaust device.
2. The apparatus according to claim 1, wherein the mixing device
includes a static mixer for mixing the gas and the deionized water,
and an injection portion for injecting the deionized water into an
upstream position of the static mixer.
3. The apparatus according to claim 2, further comprising: a
solvent concentration measuring device for measuring a
concentration of solvent in the gas-liquid separating device; a
control valve for adjusting a flow rate of the deionized water
injected to the injection portion; and a control device for
controlling the control valve to increase the flow rate of the
deionized water when the concentration of the solvent measured by
the solvent concentration measuring device is high, and controlling
the control valve to decrease the flow rate of the deionized water
when the concentration of the solvent measured by the solvent
concentration measuring device is low.
4. The apparatus according to claim 1, further comprising: a
discharge portion for discharging the gas through a discharge pipe
from the gas-liquid separating device; and a liquefying device
mounted on the discharge pipe for liquefying the gas discharged
from the discharge portion by compressing and cooling the gas.
5. The apparatus according to claim 2, further comprising: a
discharge portion for discharging the gas through a discharge pipe
from the gas-liquid separating device; and a liquefying device
mounted on the discharge pipe for liquefying the gas discharged
from the discharge portion by compressing and cooling the gas.
6. The apparatus according to claim 3, further comprising: a
discharge portion for discharging the gas through a discharge pipe
from the gas-liquid separating device; and a liquefying device
mounted on the discharge pipe for liquefying the gas discharged
from the discharge portion by compressing and cooling the gas.
7. The apparatus according to claim 4, wherein the liquefying
device includes an orifice for narrowing a flow passage through the
discharge pipe, and a cooling device for cooling the gas from
peripheral surfaces of the orifice, wherein the solvent liquefied
by the liquefying device is allowed to flow downstream of the
orifice.
8. The apparatus according to claim 5, wherein the liquefying
device includes an orifice for narrowing a flow passage through the
discharge pipe, and a cooling device for cooling the gas from
peripheral surfaces of the orifice, wherein the solvent liquefied
by the liquefying device is allowed to flow downstream of the
orifice.
9. The apparatus according to claim 6, wherein the liquefying
device includes an orifice for narrowing a flow passage through the
discharge pipe, and a cooling device for cooling the gas from
peripheral surfaces of the orifice, wherein the solvent liquefied
by the liquefying device is allowed to flow downstream of the
orifice.
10. The apparatus according to claim 4, wherein the liquefying
device includes a cooling device disposed in a flow passage through
the discharge pipe, and a drain pipe disposed downstream of the
cooling device, wherein the solvent liquefied by the liquefying
device is allowed to flow down through the drain pipe.
11. The apparatus according to claim 5, wherein the liquefying
device includes a cooling device disposed in a flow passage through
the discharge pipe, and a drain pipe disposed downstream of the
cooling device, wherein the solvent liquefied by the liquefying
device is allowed to flow down through the drain pipe.
12. The apparatus according to claim 6, wherein the liquefying
device includes a cooling device disposed in a flow passage through
the discharge pipe, and a drain pipe disposed downstream of the
cooling device, wherein the solvent liquefied by the liquefying
device is allowed to flow down through the drain pipe.
13-20. (canceled)
Description
BACKGROUND OF THE INVENTION
[0001] (1) Field of the Invention
[0002] This invention relates a substrate treating apparatus and a
substrate treating method for treating, such as cleaning and
etching with treating liquids or solutions, substrates such as
semiconductor wafers or glass substrates for liquid crystal
displays (hereinafter called simply substrates), and thereafter
drying the substrates with solvent vapor.
[0003] (2) Description of the Related Art
[0004] A conventional apparatus of this type includes a treating
tank for storing deionized water, a chamber enclosing the treating
tank, a holding mechanism for vertically moving substrates between
a treating position inside the treating tank and a drying position
above the treating tank, a vapor generator for generating a vapor
of isopropyl alcohol (IPA), nozzles for supplying the vapor of
isopropyl alcohol into the chamber, and an exhaust pump for
exhausting gas from the chamber (see Japanese Patent No. 3585199,
for example).
[0005] In the apparatus of such construction, the holding mechanism
holding substrates is first moved to the treating position to clean
the substrates as immersed in deionized water. Then, a vapor of
isopropyl alcohol is supplied from the nozzles to fill the chamber
with a solvent atmosphere. Subsequently, the holding mechanism
holding the substrates is moved from the treating position to the
drying position. Next, the exhaust pump is operated to exhaust gas
from and decompress the chamber, and the vapor of isopropyl alcohol
adhering to the substrates is dried to dry the substrates.
[0006] The conventional apparatus with the above construetion has
the following drawback.
[0007] With an increasingly refined process, the conventional
apparatus can have a high concentration of isopropyl alcohol in the
vapor supplied into the chamber. In such a case, the concentration
of isopropyl alcohol in the exhaust gas from the exhaust pump
becomes high, which poses a problem of imposing a load on exhaust
equipment (utility) of the user.
SUMMARY OF THE INVENTION
[0008] This invention has been made having regard to the state of
the art noted above, and its object is provide a substrate treating
apparatus and a substrate treating method that can reduce a burden
imposed on exhaust equipment by collecting a solvent in exhaust gas
to lower the solvent concentration in the exhaust gas.
[0009] The above object is fulfilled, according to this invention,
by a substrate treating apparatus for drying substrates with a
solvent vapor after treating the substrates with a treating liquid,
the apparatus comprising a treating tank for storing the treating
liquid; a holding device for holding the substrates in the treating
tank; a chamber enclosing the treating tank; a solvent vapor supply
device for supplying the solvent vapor into the chamber; an exhaust
device for exhausting gas from the chamber through an exhaust pipe
connected at one end thereof to the chamber; a drain pipe connected
at one end thereof to the chamber for draining the treating liquid
from the chamber; a gas-liquid separating device having the other
end of the exhaust pipe connected thereto for receiving the gas
exhausted by the exhaust device, and having the other end of the
drain pipe connected thereto for receiving the treating liquid
drained through the drain pipe, the gas-liquid separating device
separating the gas and the liquid; and a mixing device mounted on
the exhaust pipe for mixing deionized water into the gas exhausted
by the exhaust device.
[0010] According to this invention, the gas exhausted by the
exhaust device from the chamber through the exhaust pipe having one
end connected to the chamber is mixed with deionized water by the
mixing device and fed into the gas-liquid separating device. Even
if the solvent vapor is included in the gas exhausted from the
chamber, the solvent vapor melts into the deionized water. This
reduces the concentration of solvent included in the gas exhausted
from the gas-liquid separating device.
[0011] In this invention, the mixing device may include a static
mixer for mixing the gas and the deionized water, and an injection
portion for injecting the deionized water into an upstream position
of the static mixer.
[0012] By injecting deionized water from the injection portion, the
gas exhausted from the chamber and the deionized water are mixed by
the static mixer. Thus, the solvent vapor can fully melt into the
deionized water. This further reduces the concentration of solvent
included in the gas exhausted from the gas-liquid separating
device.
[0013] In this invention, the apparatus may further comprise a
solvent concentration measuring device for measuring a
concentration of solvent in the gas-liquid separating device; a
control valve for adjusting a flow rate of the deionized water
injected to the injection portion; and a control device for
controlling the control valve to increase the flow rate of the
deionized water when the concentration of the solvent measured by
the solvent concentration measuring device is high, and controlling
the control valve to decrease the flow rate of the deionized water
when the concentration of the solvent measured by the solvent
concentration measuring device is low.
[0014] The control device controls the control valve to increase
the flow rate of the deionized water when the concentration of the
solvent measured by the solvent concentration measuring device is
high, and controls the control valve to decrease the flow rate of
the deionized water when the concentration of the solvent measured
by the solvent concentration measuring device is low. Thus, the
solvent concentration can be reduced irrespective of variations in
the solvent concentration in the gas exhausted from the
chamber.
[0015] In this invention, the apparatus may further comprise a
discharge portion for discharging the gas through a discharge pipe
from the gas-liquid separating device; and a liquefying device
mounted on the discharge pipe for liquefying the gas discharged
from the discharge portion by compressing and cooling the gas.
[0016] The liquefying device liquefies the gas discharged from the
discharge portion by compressing and cooling the gas. This further
reduces the concentration of solvent included in the gas exhausted
from the gas-liquid separating device.
[0017] In this invention, the liquefying device may include an
orifice for narrowing a flow passage through the discharge pipe,
and a cooling device for cooling the gas from peripheral surfaces
of the orifice, wherein the solvent liquefied by the liquefying
device is allowed to flow downstream of the orifice.
[0018] The cooling device cools the gas from peripheral surfaces of
the orifice, and a solvent liquefied by the cooling device is
allowed to flow downstream. Thus, the solvent included in the gas
can be liquefied and discharged efficiently.
[0019] In this invention, the liquefying device may include a
cooling device disposed in a flow passage through the discharge
pipe, and a drain pipe disposed downstream of the cooling device,
wherein the solvent liquefied by the liquefying device is allowed
to flow down through the drain pipe.
[0020] The cooling device is disposed in the flow passage through
the discharge pipe. This cooling device cools the gas in the
discharge pipe, and the solvent liquefied by the liquefying device
is allowed to flow down through the drain pipe. Thus, the solvent
included in the gas can be liquefied and discharged
efficiently.
[0021] In another aspect of the invention, a substrate treating
method is provided for drying substrates with a solvent vapor after
treating the substrates with a treating liquid, the method
comprising a step of carrying out chemical treatment of the
substrates immersed in treating liquids including a chemical
solution stored in a treating tank; a step of decompressing an
interior of a chamber enclosing the treating tank, to a
predetermined pressure through an exhaust pipe communicating with
the chamber; a step of supplying the solvent vapor into the
chamber; a step of moving the substrates above the treating tank; a
step of resuming decompression of the interior of the chamber
through the exhaust pipe, and mixing deionized water into a gas
flowing through the exhaust pipe, by a mixing device; and a step of
separating and discharging the gas and liquid through a gas-liquid
separating device downstream of the mixing device.
[0022] After chemical treatment, the substrates are cleaned with
deionized water. Subsequently, the interior of the chamber is
decompressed and the solvent vapor is supplied into the chamber. In
a state of solvent vapor atmosphere formed in the chamber, the
substrates are moved up to replace the deionized water adhering to
the substrates with the solvent. Then, the decompression is resumed
to dry the solvent adhering to the substrates. The gas exhausted
from the chamber is mixed with deionized water by the mixing device
and fed into the gas-liquid separating device. Even if the solvent
vapor is included in the gas exhausted from the chamber, the
solvent vapor melts into the deionized water. This reduces the
concentration of solvent included in the gas exhausted from the
gas-liquid separating device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] For the purpose of illustrating the invention, there are
shown in the drawings several forms which are presently preferred,
it being understood, however, that the invention is not limited to
the precise arrangement and instrumentalities shown.
[0024] FIG. 1 is a block diagram showing an outline of a substrate
treating apparatus according to this invention;
[0025] FIG. 2 is a view in vertical section showing an outline of a
static mixer;
[0026] FIG. 3 is a view in vertical section showing an outline of a
gas-liquid separator;
[0027] FIG. 4 is a view in vertical section showing an outline of a
liquefying unit;
[0028] FIG. 5 is a flow chart of operation; and
[0029] FIG. 6 is a view in vertical section showing an outline of a
modified liquefying unit.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] A preferred embodiment of this invention will be described
in detail hereinafter with reference to the drawings.
[0031] FIG. 1 is a block diagram showing an outline of a substrate
treating apparatus according to this invention.
[0032] The substrate treating apparatus in this embodiment includes
a treating tank 1 for storing a treating liquid or solution. The
treating tank 1 storing the treating liquid can receive a plurality
of wafers W in upstanding posture. The treating tank 1 has two jet
pipes 3 arranged in the bottom thereof for supplying the treating
liquid, the jet pipes 3 having long axes extending in a direction
of arrangement of the wafers W (i.e. perpendicular to the plane of
FIG. 1). Each jet pipe 3 is connected to one end of a supply pipe
5. The other end of the supply pipe 5 is connected to a treating
liquid source 7. The flow rate of the treating liquid through the
supply pipe 5 is controlled by a treating liquid valve 9 consisting
of a control valve.
[0033] The treating tank 1 has an upper portion thereof enclosed in
a chamber 11. The chamber 11 has an openable top cover 13. A lifter
15 for holding the wafers W in upstanding posture is movable
between a "standby position" above the chamber 11, a "treating
position" inside the treating tank 1, and a "drying position" above
the treating tank 1 and inside the chamber 11.
[0034] A pair of solvent nozzles 17 and a pair of inert gas nozzles
19 are arranged under the top cover 13 and on an upper inner wall
of the chamber 11. Each solvent nozzle 17 is connected to one end
of a feed pipe 21. The other end of the feed pipe 21 is connected
to a vapor generator 23. The feed pipe 21 has, arranged thereon
from upstream to downstream, a vapor valve 25 consisting of a
control valve for adjusting a flow rate of solvent vapor, a
flowmeter 27 for detecting a flow rate of solvent vapor, and an
in-line heater 29 for heating the solvent vapor. The feed pipe 21
has a larger diameter (about 9.52 mm) than in a conventional
apparatus to reduce channel resistance to the solvent vapor in the
feed pipe 21, thereby to supply the vapor smoothly from the vapor
generator 23 to the solvent nozzles 17.
[0035] The vapor generator 23 has a heater (not shown) mounted
therein for generating a vapor of solvent by controlling or heating
an interior space thereof serving as a vapor generating space to a
predetermined temperature, thereby vaporizing the solvent supplied
into the interior space. The solvent used herein may be isopropyl
alcohol (IPA), for example. Further, the vapor generator 23 has a
vacuum pump (not shown) connected thereto for decompressing the
interior space.
[0036] The solvent nozzles 17 correspond to the "solvent vapor
supply device" in this invention.
[0037] Each inert gas nozzle 19 is connected to one end of a feed
pipe 31. The other end of the feed pipe 31 is connected to an inert
gas source 33 for supplying an inert gas. The feed pipe 31 has,
arranged thereon from upstream to downstream, an inert gas valve 35
consisting of a control valve for controlling a flow rate, and an
in-line heater 37 for heating the inert gas to a predetermined
temperature. The inert gas may be nitrogen gas (N.sub.2), for
example.
[0038] A vacuum pump 39 is provided which can discharge liquid even
when the interior of chamber 11 is decompressed. One end of an
exhaust pipe 41 is connected to a suction side of the vacuum pump
39, while the other end is connected to the bottom of the chamber
11. The exhaust pipe 41 has a vacuum valve 43 mounted thereon for
switching operation. The vacuum pump 39, preferably, is a seal
water type vacuum pump capable of discharging liquid even in a
decompression environment.
[0039] The vacuum pump 39 corresponds to the "exhaust device" in
this invention.
[0040] A breather valve 45 consisting of a switch valve is attached
to the chamber 11 for canceling a decompressed state. Further, the
chamber 11 has a pressure gauge 47 for detecting internal
pressure.
[0041] The treating tank 1 has an outlet port 49 formed in the
bottom thereof. The outlet port 49 has a QDR valve 51 connected
thereto. When the treating liquid in the treating tank 1 is
discharged from the QDR valve 51, the treating liquid will once be
discharged to the bottom of the chamber 11. A drain pipe 55
connected to a gas-liquid separator 53 is attached to the bottom of
the chamber 11. The drain pip 55 has a drain valve 57 mounted
thereon. The gas-liquid separator 53 receives the gas and liquid
from the exhaust pipe 41 and drain pipe 55, and separates and
discharges the gas and liquid.
[0042] While a detailed construction of the gas-liquid separator 53
will be described hereinafter, the gas-liquid separator 53 has
intake ports 59 for taking in the gas and liquid. Connected to the
intake ports 59 are a downstream end of the drain pipe 55, and a
downstream end of an exhaust pipe 61 which receives exhaust gas
from the vacuum pump 39.
[0043] A static mixer 63 is mounted on the exhaust pipe 61 between
the vacuum pump 39 and gas-liquid separator 53. The static mixer 63
has an injection portion 65 disposed in an upstream position
thereof for injecting deionized water. A flow control valve 67
controls a flow rate of deionized water to the injection portion
65. As described in detail hereinafter, the static mixer 63 has no
actuator, but agitates and mixes fluids successively by action of
division, turning and reversal.
[0044] The gas-liquid separator 53 corresponds to the "gas-liquid
separating device" in this invention. The static mixer 63
corresponds to the "mixing device" in this invention.
[0045] Next, reference is made to FIG. 2 which is a view in
vertical section showing an outline of the static mixer 63.
[0046] The static mixer 63 includes a cylindrical body 69 and a
plurality of elements 71 arranged in series in the body 69. Each
element 71 is in the form of a rectangular plate member twisted 180
degrees. Adjoining elements 71 are twisted in opposite directions.
The static mixer 63 has the above-noted injection portion 65
disposed in the upstream position thereof for injecting deionized
water into the exhaust gas (including air, nitrogen, solvent vapor,
and water vapor) flowing through the exhaust pipe 61, and agitates
and mixes the liquid and gas by action of division, turning and
reversal. Such mixing action can improve the efficiency of gas and
liquid separation by the gas-liquid separator 53.
[0047] Next, reference is made to FIG. 3 which is a view in
vertical section showing an outline of the gas-liquid separator
53.
[0048] The gas-liquid separator 53 includes a housing 73, an
introducing portion 74 in the bottom of the housing 73, a filter 75
for filtering the exhaust gas and liquid from the introducing
portion 74, a first storage portion 77 for storing part having a
high specific gravity of the substance having passed the filter 75,
a second storage portion 79 for storing part having a low specific
gravity, the intake ports 59 for taking the gas and liquid into the
introducing portion 74, a first discharge portion 81 for
discharging the liquid from the first storage portion 77, a second
discharge portion 83 for discharging the gas from the second
storage portion 79, and a cooling pipe 85 arranged along the outer
wall of housing 73 for indirectly cooling the filter 75. The filter
75 is a microfiber filter having a function to trap a
differentiated free liquid and flocculate the liquid into coarse
masses. The free liquid differentiated to the order of microns is
flocculated to the order of millimeters, thereby to be
instantaneously distributed into a perfect bilayer system by
specific gravity difference. The housing 73 has a concentration
meter 87 disposed in an upper position thereof for measuring a
solvent concentration in the second storage portion 79.
[0049] The cooling pipe 85 cools the filter 75 to a temperature
lower than the temperature of the exhaust gas. When, for example,
the temperature of the vapor of isopropyl alcohol is 50.degree. C.,
the filter 75 may be cooled to a temperature below 50.degree.
C.
[0050] A controller 89, which corresponds to the "control device"
in this invention, performs an overall control of the apparatus
including the vertical movement of the lifter 15, operation and
stopping of the vacuum pump 39, temperature control of the in-line
heaters 29 and 37, and opening and closing of the control valves
such as treating liquid valve 9, vapor valve 25, inert gas valve
35, vacuum valve 43, breather valve 45, QDR valve 51 and flow
control valve 67. The output signals of the pressure gauge 47 and
concentration meter 87 are given to the controller 89.
[0051] The controller 89 refers to the output signal of the
concentration meter 87, operates the flow control valve 67 to
increase the deionized water flow rate when the solvent
concentration is high, and operates the flow control valve 67 to
decrease the deionized water flow rate when the solvent
concentration is low. Thus, when the solvent concentration in the
exhaust gas is high, deionized water is increased to take in the
solvent in the exhaust gas easily, and when the solvent
concentration in the exhaust gas is low, deionized water is
decreased to reduce consumption of the deionized water. As a
result, the solvent concentration is reduced regardless of
variations in the solvent concentration in the exhaust gas.
[0052] Next, reference is made to FIG. 4 which is a view in
vertical section showing an outline of a liquefying unit.
[0053] An exhaust pipe of the second exhaust portion 83 includes a
liquefying unit 95 having an orifice 91 which narrows the flow
passage through the exhaust pipe to a small cross-sectional area,
and a cooler 93 mounted peripherally of the orifice 91 for cooling
the fluid flowing through the orifice 91. The cooler 93 cools the
fluid to a temperature below an exhaust gas temperature. When, for
example, the temperature of the vapor of isopropyl alcohol is
50.degree. C., the fluid may be cooled to a temperature below
50.degree. C.
[0054] The cooler 93 may, for example, be the type using a Peltier
device, or the type that circulates a coolant through a channel.
Since the vapor of isopropyl alcohol is included in the gas, the
type using a coolant is preferred from the viewpoint of
explosion-proof construction.
[0055] The orifice 91, preferably, has a cooling member 97 forming
a labyrinth structure for increasing an area of contact with the
gas. This cooling member 97 includes a plurality of mesh elements
99 each having cooled portions and portions passing the exhaust
gas. Adjoining mesh elements 99 are arranged to stagger the
portions passing the gas as seen in the direction of passage.
Consequently, the gas flows while contacting the cooled portions of
at least certain of the mesh elements 99, to realize improved
cooling effect.
[0056] Next, operation of the above apparatus will be described
with reference to FIG. 5. FIG. 5 is a flow chart of operation.
[0057] Steps S1 and S2
[0058] The controller 89 opens the top cover 13, and moves the
lifter 15 holding a plurality of wafers W to be treated from the
"standby position" to the "drying position" in the chamber 11. At
this time, the drain valve 57 is maintained open. Next, the
controller 89 reduces the oxygen concentration in the chamber 11.
Specifically, the controller 89 opens the inert gas valve 35 to
supply the inert gas from the inert gas source 33 through the feed
pipe 31 and inert gas nozzles 19 into the chamber 11. Thus, the
inert gas purges air in the interior of the chamber 11 and treating
tank 1, thereby reducing the oxygen concentration in the chamber
11. Further, the controller 89 lowers the lifter 15 from the
"drying position" to the "treating position" in the treating tank
1.
[0059] Step S3
[0060] The controller 89 opens the treating liquid valve 9. Then, a
chemical solution is supplied as the treating solution from the
treating liquid source 7 to the treating tank 1, and the treating
solution overflowing the treating tank 1 is collected at the bottom
of the chamber 11. The collected treating solution is fed through
the drain pipe 55 to the gas-liquid separator 53, and is discharged
through the first discharge portion 81 to a drain treating device
(not shown). This state is maintained for a predetermined time to
treat the wafers W with the treating solution.
[0061] Step S4
[0062] Upon lapse of the predetermined time after start of the
chemical treatment, the controller 89 causes deionized water to be
supplied as treating liquid to replace the chemical solution from
the treating liquid source 7, while maintaining the lifter 15 in
the "treating position". This state is maintained for a
predetermined time to clean the wafers W with the deionized
water.
[0063] Steps S5 and S6
[0064] Upon completion of the deionized water cleaning treatment,
the controller 89 closes the breather valve 45 to block off the
interior of chamber 11, and operates the vacuum pump 39 to
discharges gas from the chamber 11 to the exhaust pipe 41 to start
decompressing the chamber 11. Based on the output signal of the
pressure gauge 47, the controller 89 determines whether the
interior of the chamber 11 has reduced to a predetermined pressure,
and continues the decompression by the vacuum pump 39 until the
predetermined pressure is reached.
[0065] Step S7
[0066] The controller 89 sets the in-line heater 29 to a heating
mode for a predetermined temperature, and opens the vapor valve 25
adjusted to a predetermined flow rate. Consequently, the vapor of
isopropyl alcohol (IPA) generated in the vapor generator 23 is
supplied as heated to the predetermined temperature, through the
feed pipe 21 and solvent nozzles 17 into the chamber 11 by pressure
difference to the interior of the chamber 11. Since the vapor of
isopropyl alcohol is supplied by pressure difference, without using
a carrier gas, the vapor of isopropyl alcohol can be supplied in
high concentration into the chamber 11.
[0067] Step S8
[0068] As the vapor of isopropyl alcohol begins to be supplied into
the chamber 11 as noted above, the vapor fills the interior of the
chamber 11, and the surface of deionized water stored in the
treating tank 1 is gradually replaced by the vapor of isopropyl
alcohol. After a predetermined time, the controller 89 raises the
lifter 15 from the "treating position" to the "drying
position".
[0069] Step S9
[0070] The controller 89 resumes the decompression by the vacuum
pump 39, thereby to exhaust, through the exhaust pipe 41, gases in
the chamber 11, i.e. nitrogen, the vapor of isopropyl alcohol, and
water vapor from waterdrops adhering to the treating tank 1 and
chamber 11. Sealing water leaving the sealing water type vacuum
pump 39 also flows with the exhaust gas into the exhaust pipe 61.
This exhaust gas is agitated and mixed by the static mixer 63
before being fed to the gas-liquid separator 53. Therefore, the
vapor of isopropyl alcohol is mixed with deionized water by the
gas-liquid separator 53 to be drained in liquid state. This
treatment (mixing and separation treatment) continues until the IPA
vapor is stopped, or until lapse of a predetermined time after the
IPA vapor is stopped.
[0071] Consequently, the deionized water adhering to the surfaces
of wafers W in the "drying position" is replaced by the vapor of
isopropyl alcohol.
[0072] Step S10
[0073] Next, the controller 89 closes the vapor valve 25, and stops
the vacuum pump 39. At this time, the decompression of the chamber
11 is maintained to continue drying the wafers W under reduced
pressure. After a predetermined time, the controller 89 opens the
inert gas valve 35 to introduce the inert gas from the inert gas
nozzles 19 into the chamber 11, and opens the breather valve 45 to
return the pressure in the chamber 11 to atmospheric pressure.
[0074] Step S11
[0075] The controller 89 closes the inert gas valve 35, opens the
top cover 13, and raises the lifter 15 from the "drying position"
to the "standby position" outside the chamber 11. Then, the
controller 89 opens the treating liquid valve 9, drain valve 57 and
inert gas valve 35. In this way, a new portion of the treating
solution is supplied into the treating tank 1, and the interior of
chamber 11 is filled with the inert gas, for treatment of next
wafers W.
[0076] According to the apparatus in this embodiment, as described
above, the exhaust gas is mixed with deionized water by the static
mixer 63 even if the vapor of high-concentration isopropyl alcohol
is supplied through the solvent nozzles 17 into the chamber 11
surrounding the treating tank 1. Thus, since the exhaust gas,
although including the vapor of isopropyl alcohol, is fed to the
gas-liquid separator 53 with deionized water, the vapor of
isopropyl alcohol is discharged with deionized water. As a result,
it is possible to reduce the concentration of isopropyl alcohol in
the exhaust gas from the gas-liquid separator 53.
[0077] The exhaust gas and deionized water are efficiently mixed in
the static mixer 63 by injecting deionized water from the injection
portion 65. Thus, isopropyl alcohol in the exhaust gas, the liquid
such as deionized water, and the gas are evenly mixable. This
increases the accuracy of gas-liquid separation in the gas-liquid
separator 53, to further reduce the concentration of isopropyl
alcohol in the exhaust gas.
[0078] The static mixer 63 acts as the mixing device in this
embodiment. Instead, a mixer having a movable portion may be
employed.
[0079] This embodiment provides the injection portion 65 for mixing
deionized water and exhaust gas, and the flow rate of deionized
water is adjusted according to the isopropyl alcohol concentration
in the gas-liquid separator 73. However, the injection portion 65
and flow control valve 67 may be omitted, so that the mixing action
relies simply on the static mixer 63. This simplifies the
construction, and lightens the load on the controller 89.
[0080] According to this embodiment, the gas discharged from the
second exhaust portion 83 of gas-liquid separator 53 is compressed
and cooled by the liquefying unit 95. Thus, the vapor of isopropyl
alcohol included in the gas is condensed into liquid. Therefore,
the vapor of isopropyl alcohol included in the gas is turned into
liquid to flow down the liquefying unit 95 (see FIG. 4). The vapor
of isopropyl alcohol is discharged as liquid. As a result, the
concentration of isopropyl alcohol included in the exhaust gas from
the gas-liquid separator 53 can be reduced.
[0081] According to this embodiment, the exhaust gas is compressed
by the orifice 91, and then cooled by the cooler 93. Thus, the
solvent included in the exhaust gas can be condensed
efficiently.
[0082] The above liquefying unit 95 can be replaced with a
liquefying unit 95A as shown in FIG. 6.
[0083] Reference is now made to FIG. 6 which is a view in vertical
section showing a modified liquefying unit. This liquefying unit
95A has a cooler 93 mounted in the flow passage of the exhaust pipe
from the second exhaust unit 83, and a drain pipe 101 disposed
downstream thereof. Although the orifice 91 as in the liquefying
unit 95 described hereinbefore is not provided here, the cooler 93
mounted in the flow passage narrows the passage as a result. Thus,
the liquefying unit 95A has a function and effect similar to the
foregoing liquefying unit 95. The exhaust gas is directly cooled by
the cooler 93 to increase liquefying efficiency. The condensed
solvent flows down the drain pipe 101 to be discharged.
[0084] The above liquefying units 95 and 95A correspond to the
"liquefying device" in this invention. The above cooler 93
corresponds to the "cooling device" in this invention.
[0085] A blower (pressurizer) may be provided upstream of the
liquefying unit 95 (95A) to increase exhaust gas pressure, thereby
to promote liquefying effect by compression.
[0086] This invention is not limited to the foregoing embodiment,
but may be modified as follows:
[0087] (1) In the foregoing embodiment, the treating tank 1 has a
single tank construction. Instead, a double tank construction may
be employed, which includes an inner tank, and an outer tank for
collecting the treating liquid or solution overflowing the inner
tank.
[0088] (2) The foregoing embodiment uses, by way of example,
isopropyl alcohol as solvent. This invention is not limited to this
solvent. Other solvents may be used to provide similar functions
and effects.
[0089] (3) The foregoing embodiment provides a construction for
supplying nitrogen gas into the chamber 11 to reduce oxygen
concentration. This construction is not absolutely necessary.
[0090] This invention may be embodied in other specific forms
without departing from the spirit or essential attributes thereof
and, accordingly, reference should be made to the appended claims,
rather than to the foregoing specification, as indicating the scope
of the invention.
* * * * *