U.S. patent application number 11/662019 was filed with the patent office on 2007-11-08 for pump unit for supplying chemical liquids.
Invention is credited to Kazuhiro Arakawa, Shigenobu Itoh, Katsuya Okumura.
Application Number | 20070258837 11/662019 |
Document ID | / |
Family ID | 36036202 |
Filed Date | 2007-11-08 |
United States Patent
Application |
20070258837 |
Kind Code |
A1 |
Okumura; Katsuya ; et
al. |
November 8, 2007 |
Pump Unit for Supplying Chemical Liquids
Abstract
A pump unit for supplying chemical liquids capable of reducing
the trapping of air bubbles and chemical liquids inside the
chemical liquid passage of the unit while reducing the size by
forming the pump and open/close valves in the vicinity of the pump
into a single unit. The pump unit 10 is formed by integrally
mounting a suction-side passage member 17 with which a suction-side
shutoff valve 13 is assembled together and a discharge-side passage
member 18 with which a discharge side shutoff valve 14 is assembled
together on the pump 11 (pump housings 21, 22). Suction passages
17a and 21b and discharge passages 18a and 21c communicating with a
pump chamber 25 are disposed on the same line L1.
Inventors: |
Okumura; Katsuya; (Tokyo,
JP) ; Arakawa; Kazuhiro; (Aichi, JP) ; Itoh;
Shigenobu; (Aichi, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Family ID: |
36036202 |
Appl. No.: |
11/662019 |
Filed: |
July 29, 2005 |
PCT Filed: |
July 29, 2005 |
PCT NO: |
PCT/JP05/13920 |
371 Date: |
March 9, 2007 |
Current U.S.
Class: |
417/472 |
Current CPC
Class: |
F04B 53/06 20130101;
F04B 43/06 20130101 |
Class at
Publication: |
417/472 |
International
Class: |
F04B 43/02 20060101
F04B043/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2004 |
JP |
2004-264423 |
Claims
1.-6. (canceled)
7. A pump unit for supplying chemical liquids, provided with a pump
having a pump chamber for suctioning and discharging a chemical
liquid, a suction-side open/close valve that is connected to the
pump chamber and which opens/closes a suctioning passage for
suctioning the chemical liquid into the pump chamber, and a
discharge-side open/close valve that is connected to the pump
chamber and which opens/closes a discharging passage for
discharging the chemical liquid from the pump chamber; wherein both
the suctioning passage and the discharging passage are nearly
linear in shape and are disposed on the same line; and the pump,
the suction-side open/close valve, and the discharge-side
open/close valve are assembled together; and the pump unit, also
provided with a suction-side passage member with which the
suction-side open/close valve is assembled together, and a
discharge-side passage member with which the discharge-side
open/close valve is assembled together; and wherein the pump has a
pump housing, and the pump housing has a thin flat shape provided
with an internal diaphragm that comprises part of the pump chamber,
the suction-side passage member and the discharge-side passage
member are both rod-shaped and are disposed along the flat
direction of the pump housing, and the suction-side open/close
valve and the discharge-side open/close valve are disposed
perpendicularly to the suction-side passage member and the
discharge-side passage member, respectively, and along the flat
direction of the pump housing.
8. The pump unit for supplying chemical liquids according to claim
7, wherein the pump housing and the passage members have internal
passages, a seal ring for preventing the chemical liquid inside the
internal passages of the pump housing and the passage members from
leaking through the gap between the pump housing and the individual
passage member is provided between the pump housing and the
individual passage member, and an inner peripheral surface of the
seal ring is formed in a shape that is smoothly continuous with
inner peripheral surfaces of the internal passages upstream and
downstream of the seal ring.
9. The pump unit for supplying chemical liquids according to claim
8, wherein a suckback valve that sucks in a predetermined amount of
the chemical liquid inside the discharge passage is assembled into
the downstream side of the suction-side open/close valve.
10. The pump unit for supplying chemical liquids according to claim
9, wherein at least one of the valves is operated by operating air
that is supplied/withdrawn and at least one of the
electro-pneumatic regulators that control the operating air is
integrally assembled.
11. The pump unit for supplying chemical liquids according to claim
7, wherein a suckback valve that sucks in a predetermined amount of
the chemical liquid inside the discharge passage is assembled into
the downstream side of the suction-side open/close valve.
12. The pump unit for supplying chemical liquids according to claim
11, wherein at least one of the valves is operated by operating air
that is supplied/withdrawn and at least one of the
electro-pneumatic regulators that control the operating air is
integrally assembled.
13. The pump unit for supplying chemical liquids according to claim
7, wherein at least one of the valves is operated by operating air
that is supplied/withdrawn and at least one of the
electro-pneumatic regulators that control the operating air is
integrally assembled.
Description
TECHNICAL FIELD
[0001] The present invention relates to a pump unit for supplying
chemical liquids that is suitable for applying a predetermined
volume of a chemical liquid, such as a photoresist liquid, to
individual semiconductor wafers in the chemical-using process of a
semiconductor manufacturing device, for example.
BACKGROUND ART
[0002] In a chemical liquid supply system, in order to pump a
chemical liquid such as a photoresist out of a bottle and apply a
predetermined volume of this liquid to individual semiconductor
wafers, a pump and various necessary open/close valves individually
disposed in the vicinity of the pump are usually connected using
tubes. However, in such a system configuration, each tube
connection requires a coupling, and the space necessary for
installing these tubes and couplings increases the size of the
chemical liquid supply system.
[0003] Furthermore, to apply a chemical liquid simultaneously to
multiple semiconductor wafers, multiple processing chambers
(chambers in which the chemical liquid is applied to semiconductor
wafers) are usually stacked vertically in several stages. However,
the spaces inside these processing chambers are too small to house
all of the necessary items, such as the nozzles for discharging the
chemical liquid into the processing chambers, the discharge-side
open/close valves, the pump, and the suction-side open/close
valves. Only the nozzles and the discharge-side open/close valves
can be positioned inside the processing chambers, while the pump,
the suction-side open/close valves and the others must be gathered
inside a housing area provided below the processing chambers.
Consequently, the length of the tube downstream of the pump and the
height from the pump to the nozzle (pump head) differ for the
individual processing chambers, resulting in differing levels of
pressure loss. Such differences can cause the volume of chemical
liquid discharged from the individual processing chambers to vary,
making it difficult to ensure a uniform discharging volume among
all of the processing chambers.
[0004] Therefore, in the chemical liquid supply system disclosed in
patent reference 1 for example, the pump and the necessary
open/close valves (input valves and output valves) in the vicinity
of the pump are assembled together into a single unit. That is, a
small pump unit is formed by omitting the tubes between the pump
and the individual open/close valves and the required couplings,
and such a pump unit can be provided for each processing chamber.
As a result, the tube length and the height between the pump and
the nozzle (pump head) can be made uniform for all processing
chambers, making it easy to obtain a uniform discharge volume for
all processing chambers.
[0005] In addition, immediately after an empty bottle is replaced
with a new bottle filled with a chemical liquid, for example, air
bubbles can enter the chemical liquid passage. Since these air
bubbles would prevent the specified volume of chemical liquid from
being discharged, the bubbles must be removed from the chemical
liquid passage, and in this case, a predetermined volume of
chemical liquid is purged (released) from the nozzle to expel the
air bubbles.
[0006] Since chemical liquids such as photoresists are expensive,
it is important to minimize the volume of chemical liquid to be
purged in the process of expelling the air bubbles. However, in the
pump unit in patent reference 1, there is a 90-degree difference
between the chemical liquid introduction direction in the input
port and the chemical liquid discharge direction in the output
port, and moreover, there are complicated bends in the chemical
liquid passage inside the pump unit from the input port to the
output port. That is, the fact that air bubbles become trapped in
some areas inside the chemical liquid passage prevents them from
being reliably expelled using a small purging volume, necessitating
a problematically large purge volume. The chemical liquid also
becomes trapped in the same areas as the air bubbles, and extended
exposure to the trapped air can problematically deteriorate.
Patent reference 1: Japanese Published Patent Application No.
2003-49778
DISCLOSURE OF THE INVENTION
[0007] An object of the present invention is to reduce the size of
the pump unit by forming the pump and the individual open/close
valves in the vicinity of the pump into a single unit and to
provide a pump unit for supplying chemical liquids that can reduce
the trapping of air bubbles and chemical liquid inside the chemical
liquid passage of the unit.
[0008] A pump unit for supplying chemical liquids according to the
present teaching is configured as described below. That is, a pump
unit for supplying chemical liquids can be provided with a pump
having a pump chamber for suctioning and discharging a chemical
liquid, a suction-side open/close valve that is connected to the
pump chamber and which opens/closes a suctioning passage for
suctioning the chemical liquid into the pump chamber, and a
discharge-side open/close valve that is connected to the pump
chamber and which opens/closes a discharging passage for
discharging the chemical liquid from the pump chamber. In this pump
unit, both of the suctioning passage and the discharging passage
are nearly linear in shape and are disposed on the same line, and
the pump, the suction-side open/close valve, and the discharge-
side open/close valve are assembled together.
[0009] In this pump unit for supplying chemical liquids, the
suctioning passage and discharging passage connected to the pump
chamber are both nearly linear in shape, and the pump, the
suction-side open/close valve that opens/closes the suctioning
passage, and the discharge-side open/close valve that opens/closes
the discharging passage are assembled together such that the
suctioning passage and the discharging passage are disposed on the
same line. Assembling the pump, the suction-side open/close valve,
and the discharge-side open/close valve together in this manner
eliminates the couplings and tube that would be required for
connecting the pump to the suction-side open/close valve, as well
as the couplings and tube that would be required for connecting the
pump to the discharge-side open/close valve, resulting in a compact
pump unit. As a result, the pump unit can be housed inside the
processing chamber, and the length of the tube downstream of the
pump and the height from the pump to the nozzle (pump head) can be
made uniform for all individual processing chambers, thus
preventing variations in the discharge volume. Moreover, the fact
that the suctioning passage and discharging passage connected to
the pump chamber are both nearly linear in shape and are disposed
on the same line nearly eliminates areas inside the chemical liquid
passage of the pump unit where air bubbles or chemical liquid could
become trapped. This allows the air bubbles to be reliably expelled
using only a small purging volume and reduces chemical liquid
deterioration.
[0010] A specific example of the pump unit for supplying chemical
liquid can be a pump unit for supplying chemical liquids, provided
with a pump having a pump chamber for suctioning and discharging a
chemical liquid, a suction-side open/close valve that is connected
to the pump chamber and that opens/closes a suctioning passage for
suctioning the chemical liquid into the pump chamber, and a
discharge-side open/close valve that is connected to the pump
chamber and that opens/closes a discharging passage for discharging
the chemical liquid from the pump chamber. This pump unit can be
provided with a suction-side passage member having a nearly linear
internal passage and with which the suction-side open/close valve
is assembled together, and a discharge-side passage member having a
nearly linear internal passage and with which the discharge-side
open/close valve is assembled together. In this pump unit, the pump
may be provided inside its pump housing with a nearly linear
internal passage that is connected to the internal passage to
comprise the suction passage and a nearly linear internal passage
that is connected to the internal passage to comprise the discharge
passage. Furthermore, the suction-side passage member and the
discharge-side passage member are assembled together with the pump
housing such that the suction passage and the discharge passage are
disposed on the same line.
[0011] In this pump unit for supplying chemical liquids, the
suction passage connected to the pump chamber (the internal passage
of the pump housing and the internal passage of the suction-side
passage member) and the discharge passage (the internal passage of
the pump housing and the internal passage of the discharge-side
passage member) both have a nearly linear shape, and the
suction-side passage member and the discharge-side passage member
are assembled together with the pump housing such that the suction
passage and the discharge passage are disposed on the same line.
That is, the fact that the suction-side open/close valve is
assembled together with the suction-side passage member and the
discharge-side open/close valve is assembled together with the
discharge-side passage member eliminates the couplings and tube
that would be required for connecting the pump to the suction-side
open/close valve, as well as the couplings and tube that would be
needed for connecting the pump to the discharge-side open/close
valve, resulting in a compact pump unit. As a result, the pump unit
can be housed inside the processing chamber, and the length of the
tube downstream of the pump and the height from the pump to the
nozzle (pump head) can be made uniform for all individual
processing chambers, thus preventing variations in the discharge
volume. Moreover, the fact that the suctioning passage and
discharging passage connected to the pump chamber are both nearly
linear in shape and are disposed on the same line nearly eliminates
areas inside the chemical liquid passage of the pump unit where air
bubbles or chemical liquid could become trapped. This allows the
air bubbles to be reliably expelled using only a small purging
volume and reduces generation of deteriorated chemical liquid.
[0012] In the pump unit for supplying chemical liquid shown as a
specific example, a seal ring for preventing the chemical liquid
inside the internal passages from leaking through the gap between
the pump housing and the individual passage member can be provided
between the pump housing and the individual passage member, and an
inner peripheral surface of the seal ring is preferably formed in a
shape that is smoothly continuous with inner peripheral surfaces of
the internal passages upstream and downstream of the seal ring.
[0013] In this configuration, the inner peripheral surface of the
seal ring is smoothly continuous with the inner peripheral surfaces
of the internal passages provided in the pump housing and
individual passage members. Here, a shape that is smoothly
continuous means a shape that does not produce any acute- angled
dips between the internal passages upstream and downstream of the
seal ring, and for example, means a shape that is continuous with
the inner peripheral surfaces of the internal passages and in which
a concave area gradually deepens toward the outside in the radial
direction as the distance from the internal passage toward the
center of the seal ring in its thickness direction increases. Such
a shape allows the chemical liquid to flow smoothly in the seal
ring area, preventing the trapping of the chemical liquid and air
bubbles.
[0014] Furthermore, the pump housing may have a thin flat shape
provided with an internal diaphragm, the suction-side passage
member and the discharge-side passage member can be both rod-shaped
and may be disposed along the flat direction of the pump housing,
and the suction-side open/close valve and the discharge-side
open/close valve should preferably be disposed perpendicularly to
the suction-side passage member and the discharge-side passage
member, respectively, and along the flat direction of the pump
housing.
[0015] In this configuration, the pump (pump housing) equipped with
a diaphragm may have a thin flat shape that extends in the
direction of the diaphragm. When the rod-shaped suction-side
passage member and discharge-side passage member are disposed along
the flat direction of such a pump housing, the passage members
either do not protrude at all in the direction perpendicular to the
flat direction or protrude very little. Furthermore, when the
suction-side open/close valve and the discharge-side open/close
valve are disposed in the direction perpendicular to the
suction-side passage member and discharge-side passage member and
along the flat direction of the pump housing, the open/close valves
either do not protrude at all in the direction perpendicular to the
flat direction or protrude very little, nor do they protrude much
in the flat direction. As a result, the pump unit can be made thin
and compact.
[0016] In the above configurations, it is preferable to assemble a
suckback valve that sucks in a predetermined amount of the chemical
liquid inside the discharge passage into the downstream side of the
suction-side open/close valve.
[0017] The suckback valve must be disposed on the downstream side
(for example, the farthest downstream area of the chemical liquid
passage) of the discharge-side open/close valve, and is more likely
to be disposed inside a processing chamber. Assembling such a
suckback valve together with a pump unit for supplying chemical
liquids eliminates the tubes and couplings that would be required
for connecting the suckback valve. That is, the absence of tubes
and couplings allows the pump unit for supplying chemical liquid to
be made that much smaller compared to a case in which the suckback
valve is separately installed. Note that disposing this suckback
valve along the flat direction of the pump, as were the open/close
valves in the aforementioned configuration, also helps to reduce
the size (thickness) of the pump unit.
[0018] Furthermore, in the aforementioned configurations, it is
preferable for at least one of the valves to be operated by
operating air that is supplied/withdrawn and at least one of the
electro-pneumatic regulators that control the operating air to be
assembled together with the pump unit.
[0019] For example, if a space for disposing the electro-pneumatic
regulators that control the operating air for operating the various
aforementioned valves is available near the pump unit for supplying
chemical liquids, assembling the electro-pneumatic regulators into
the pump unit reduces the number of parts to be attached to the
chemical liquid supply system. Note that also disposing these
electro-pneumatic regulators in the flat direction of the pump
helps to reduce the size (thickness) of the pump unit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a frontal cross-sectional diagram illustrating the
pump unit inside the chemical liquid supply system.
[0021] FIG. 2 (a) is a side cross-sectional diagram of the pump
unit, and (b) is an enlarged cross-sectional diagram of (a).
[0022] FIG. 3 is a circuit diagram illustrating the entire
circuitry of the chemical liquid supply system.
REFERENCE SYMBOLS
[0023] 11 . . . pump; 13 . . . suction-side shutoff valve
(suction-side open/close valve); 14 . . . discharge-side shutoff
valve (discharge-side open/close valve); 15 . . . suckback valve;
17 . . . suction-side passage member; 17a . . . suction passage; 18
. . . discharge-side passage member; 18a . . . discharge passage;
21 and 22 . . . pump housing; 21b . . . suction passage; 21c . . .
discharge passage; 25 . . . pump chamber; 33 and 34 . . . seal
rings; 33a and 34a . . . inner peripheral surfaces; L1 . . . line;
R . . . resist liquid.
PREFERRED EMBODIMENTS FOR THE INVENTION
[0024] An embodiment in which the present invention is implemented
into a pump unit of a chemical liquid supply system used in a
manufacturing line of a semiconductor device, etc. is explained
below, referencing the drawings. Note that FIG. 1 and FIG. 2
illustrate a pump unit 10, which is a primary component of the
system, while FIG. 3 illustrates the entire chemical liquid supply
system.
[0025] As shown in FIGS. 1 and 2, the pump unit 10 is formed by
assembling together a pump 11, a solenoid switching valve 12, a
suction-side shut-off valve 13, a suckback valve 15, a regulator
16, a suction-side passage member 17 and a discharge-side passage
member 18.
[0026] The pump 11 has a thin flat prism form having a nearly
square shape when viewed from the front, and has a pair of pump
housings 21 and 22. Concave sections 21a and 22a, opened in almost
circular dome shapes, are formed in the center of the opposing
faces of pump housings 21 and 22, respectively. In the pump
housings 21 and 22, the peripheries of the concave sections 21a and
22a hold and support a diaphragm 23 comprised of a circular
flexible film made of a fluorine resin or the like, and the pump
housings 21 and 22 are secured to each other using eight screws
24.
[0027] A diaphragm 23 partitions the space formed by the concave
sections 21a and 22a of the pump housings 21 and 22, with the space
on the side of pump housing 21 (the left side of the diaphragm 23
in FIG. 2) used as a pump chamber 25 and the space on the side of
pump housing 22 (the right side of the diaphragm 23 in FIG. 2) used
as an operating chamber 26. The pump chamber 25 is a space for
supplying/withdrawing the resist liquid R (see FIG. 3) used as a
chemical liquid, and the operating chamber 26 is a space for
supplying/withdrawing the operating air for driving the diaphragm
23.
[0028] A suction passage 21b, which is connected to the pump
chamber 25 and extends linearly downward, is formed in pump housing
21 on the pump chamber 25 side. The suction passage 21b is
connected to suction passage 17a of the suction-side passage member
17. A discharge passage 21c, which is connected to the pump chamber
25 and extends linearly upward, is also formed in the pump housing
21. Furthermore, this discharge passage 21c is provided on the same
line L1 as the suction passage 21b. Since the pump chamber 25 in
this embodiment is formed as a thin space in the thickness
direction of the diaphragm 23, the suction passage 21b and
discharge passage 21c connected to this pump chamber 25 are bent
perpendicularly near the pump chamber 25 to the degree necessary
for connection (roughly equaling the width of the passage) (see
FIG. 2). However, these bends do not significantly impact (create
resistance to) the flow of the resist liquid R inside the pump 11,
but allow the resist liquid R to flow smoothly in these areas.
[0029] A supply/withdrawal passage 22b, which supplies operating
air to the operating chamber 26, is formed in the pump housing 22
on the operating chamber 26 side. The supply/withdrawal passage 22b
is connected to the solenoid switching valve 12 secured to the pump
housing 22. Here, the solenoid switching valve 12 is connected to a
supply source 29 via a supply tube 28 having an electropneumatic
regulator 27 in the middle, as shown in FIG. 3. The
electropneumatic regulator 27 has an exhaust port that can be
opened to the atmosphere and is adjusted by a controller 50, such
that the pressure of the operating air supplied from the supply
source 29 to the pump 11 remains constant at a preset value. The
solenoid switching valve 12 is switched so that the controller 50
either connects the operating chamber 26 to the supply tube 28 or
opens it to the atmosphere. This switching action either supplies
operating air to or withdraws it from the operating chamber 26,
thereby switching the pump 11 between suctioning and discharging
actions.
[0030] That is, when the action of the solenoid switching valve 12
supplies operating air to the operating chamber 26, the interior of
the operating chamber 26 is pressurized, pushing the diaphragm 23
to the pump chamber 25 side and discharging the resist liquid R
contained inside the pump chamber 25 to the downstream side via the
discharge passage 21c. In contrast, when the action of the solenoid
switching valve 12 discharges the operating air inside the
operating chamber 26 to the atmosphere, the diaphragm 23, which has
been pushed to the pump chamber 25 side, moves toward the operating
chamber 26, returning to the middle position, introducing the
resist liquid R from the upstream side into the pump chamber 25 via
the suction passage 21b.
[0031] The rod-shaped, suction-side passage member 17 is secured to
the center of the bottom of the pump housings 21 and 22. The
suction-side passage member 17 is disposed along the flat direction
of the pump 11. A suction passage 17a, which extends nearly
linearly downward, is formed in the suction-side passage member 17.
This suction passage 17a is disposed on the same line L1 as the
suction passage 21b of the pump 11. On the surface of the
suction-side passage member 17 where it faces the pump housing 21,
a concave housing section 17b is formed around the suction passage
17a, and the seal ring 33 is housed inside the concave housing
section 17b. The seal ring 33 is disposed between the suction-side
passage member 17 and the pump housing 21, preventing the resist
liquid R inside the suction passages 17a and 21b from leaking out
of the gap between the suction-side passage member 17 and the pump
housing 21.
[0032] The inner peripheral surface 33a of the seal ring 33 is
smoothly continuous with the inner peripheral surfaces of the
suction passages 17a and 21b. Specifically, the seal ring 33 has a
shape in which the inner peripheral surface 33a is continuous with
the inner peripheral surfaces of the suction passages 17a and 21b,
and in which the concave area gradually deepens toward the outside
in the radial direction as the distance from the internal passages
17a or 21b toward the center of the seal ring 33 in its thickness
direction increases. In other words, this shape allows the resist
liquid R to flow smoothly in the seal ring 33 area and prevents the
resist liquid R and air bubbles from becoming trapped. Note that
using an ordinary seal ring (O-ring) having a circular cross
section creates an acute-angled dip between the seal ring and
suction passages 17a and 21b. This results in a shape that is not
smoothly continuous with the inner peripheral surfaces of the
passages 17a and 21b, and causes the resist liquid R and air
bubbles to problematically become trapped in this area.
Additionally, as shown in FIG. 3, the suction-side passage member
17, using a coupling 19 provided at its tip, is connected to one
end of a suction tube 31, while the other end of the suction tube
31 is guided into the resist liquid R contained inside a resist
bottle 30. Note that a pressurizing device not shown in the figure
keeps the interior of the resist bottle 30 under pressure.
[0033] The suction-side shutoff valve 13 consisting of an
air-operated valve is assembled together with the suction-side
passage member 17. The suction-side flow shut-off valve 13 has a
nearly square prism shape, and is disposed in the direction
perpendicular to the suction-side passage member 17 and along the
flat direction of the pump 11 (pump housings 21 and 22). Here, as
shown in FIG. 3, the suction-side flow shut-off valve 13 switches
between opening and closing the suction passage 17a based on the
switching action of an electro-pneumatic regulator 32 that is
controlled by the controller 50. That is, the suction-side flow
shut-off valve 13 has the structure shown in FIG. 1. When its
supply/withdrawal chamber 13a is opened to the atmosphere by the
switching action of the electro-pneumatic regulator 32, the valve
body 13b of the suction-side flow shut-off valve 13 receives a
spring force from a spring 13c and shuts off the suction passage
17a; when operating air is supplied to the supply/withdrawal
chamber 13a from the supply source 29, the valve body 13b sinks by
working against the spring force of the spring 13c and opens the
suction passage 17a. Note that the part of the suction passage 17a
near the valve body 13b is bent perpendicularly to the degree
necessary for ensuring the reliable opening and closing action of
the valve body 13b (roughly equaling the width of the passage).
However, this bend does not significantly impact (create resistance
to) the flow of the resist liquid R inside the passage member 17,
but allows the resist liquid R to flow smoothly in this area as
well.
[0034] The rod-shaped, discharge-side passage member 18 is secured
to the center of the top of the pump housings 21 and 22. The
discharge-side passage member 18 is disposed along the flat
direction of the pump 11. The discharge passage 18a, which extends
nearly linearly upward, is formed in the discharge-side passage
member 18. This discharge passage 18a is disposed on the same line
L1 as the discharge passage 21c of the pump 11. On the surface of
the discharge-side passage member 18 where it faces the pump
housing 21, a concave housing section 18b is formed around the
discharge passage 18a, and a seal ring 34 is housed inside the
concave housing section 18b. The seal ring 34 is disposed between
the discharge-side passage member 18 and the pump housing 21,
preventing the resist liquid R inside the discharge passages 18a
and 21c from leaking out of the gap between the discharge-side
passage member 18 and the pump housing 21.
[0035] Like the aforementioned seal ring 33, the inner peripheral
surface 34a of the seal ring 34 is smoothly continuous with the
inner peripheral surfaces of the discharge passages 18a and 21c,
resulting in a structure that prevents the resist liquid R and air
bubbles from becoming trapped. Additionally, as shown in FIG. 3,
the discharge-side passage member 18, using a coupling 20 provided
at its tip, is connected to one end of a discharge tube 35 having a
nozzle 35a on its other end. The nozzle 35a is orientated downward
and is disposed in a position that allows it to drip the resist
liquid R onto the center of a semiconductor wafer 37 that is placed
on and spins with a spinning platform 36.
[0036] A discharge-side shutoff valve 14 consisting of an
air-operated valve is assembled together with the discharge-side
passage member 18. The discharge-side flow shut-off valve 14 has a
nearly square prism shape, and is disposed in the direction
perpendicular to the discharge-side passage member 18 and along the
flat direction of the pump 11 (pump housings 21 and 22). Here, as
shown in FIG. 3, the discharge-side flow shut-off valve 14 is
constructed in the same way as the aforementioned suction-side flow
shut-off valve 13 and switches between opening and closing the
discharge passage 18a based on the switching action of an
electro-pneumatic regulator 38 that is controlled by the controller
50. That is, the discharge-side flow shut-off valve 14 has the
structure shown in FIG. 1. When its supply/withdrawal chamber 14a
is opened to the atmosphere by the switching action of the
electro-pneumatic regulator 38, a valve body 14b of the
discharge-side flow shut-off valve 14 receives a spring force from
a spring 14c and shuts off the discharge passage 18a; when
operating air is supplied to the supply/withdrawal chamber 14a from
the supply source 29, the valve body 14b sinks by working against
the spring force of the spring 14c and opens the discharge passage
18a. Note that the part of the discharge passage 18a near the valve
body 14b is bent perpendicularly to the degree necessary for
ensuring the reliable opening and closing action of the valve body
14b (roughly equaling the width of the passage). However, this bend
does not significantly impact (create resistance to) the flow of
the resist liquid R inside the passage member 18, but allows the
resist liquid R to flow smoothly in this area as well.
[0037] The suckback valve 15 consisting of an air-operated valve is
assembled together with the discharge-side passage member 18, next
to and on the downstream side of the discharge-side flow shut-off
valve 14. The suckback valve 15 also has a nearly square prism
shape, and is disposed in the direction perpendicular to the
discharge-side passage member 18 and along the flat direction of
the pump 11 (pump housings 21 and 22). Here, as shown in FIG. 3,
the suckback valve 15 is designed to suck back a predetermined
amount of the resist liquid R located downstream of the valve 15 to
the upstream side to prevent unintended dripping of the resist
liquid R from the nozzle 35a, based on the switching actions of an
electro-pneumatic regulator 39. That is, the suckback valve 15 has
the structure shown in FIG. 1. When its supply/withdrawal chamber
15a is opened to the atmosphere by the switching action of the
electro-pneumatic regulator 39, a valve body 15b of the suckback
valve 15 sinks by receiving a spring force from a spring 15c and
enlarges the volume of the volume-expansion chamber 18c connected
in communication with the discharge passage 18a, sucking in the
predetermined amount of the resist liquid R into the
volume-expansion chamber 18c. In contrast, when operating air is
supplied to the supply/withdrawal chamber 15a from the supply
source 29, the valve body 15b protrudes by working against the
spring force of the spring 15c and reduces the volume of the
volume-expansion chamber 18c provided in the discharge passage
18a.
[0038] Furthermore, the regulator 16 having the shape of an
approximate rectangular parallelepiped is secured to the
discharge-side passage member 18 on the side opposite from the
discharge-side shutoff valve 14 and the suckback valve 15. That is,
the regulator 16 is installed on the discharge-side passage member
18 along the flat direction of the pump 11. A base 41 of the
regulator 16 is secured to the discharge-side passage member 18. A
securing platform 42 is secured to the base 41, and the
electro-pneumatic regulators 38 and 39, which switch the
discharge-side shutoff valve 14 and the suckback valve 15, are
secured to the securing platform 42. A cover 43 that covers the
electro-pneumatic regulators 38 and 39 is installed on this
securing platform 42. Furthermore, communication passages 45 and
46, which are connected to the electro-pneumatic regulators 38 and
39, are respectively formed on the securing platform 42 and the
base 41, and are respectively connected to the supply/withdrawal
chambers 14a of the discharge-side shutoff valve 14 and the
supply/withdrawal chambers 15a of the suckback valve 15, though not
shown in the figure. Based on the control by the controller 50, the
electro-pneumatic regulators 38 and 39 either supply operating air
to or withdraw it from the supply/withdrawal chambers 14a of the
discharge-side shutoff valve 14 and the supply/withdrawal chambers
15a of the suckback valve 15, thereby operating the discharge-side
shutoff valve 14 and the suckback valve 15.
[0039] In the pump unit 10 thus configured, the suction passage 17a
inside the suction-side passage member 17, the suction passage 21b
and the discharge passage 21c inside the pump 11, and the discharge
passage 18a of the discharge-side passage member 18, through all of
which the resist liquid R passes, are all made linear and disposed
on the same line L1. That is, the structure of this pump unit 10
allows the length of the resist liquid R passage to be short as
much as possible, while nearly eliminating areas inside the resist
liquid R passage where the resist liquid R or air bubbles could
become trapped. The structure of the seal rings 33 and 34 also
nearly eliminates areas where the resist liquid R or air bubbles
could become trapped.
[0040] As shown in FIG. 3, the controller 50 controls a series of
actions of the chemical liquid supply system, by controlling the
electro-pneumatic regulator 27 to set the operating air supplied to
the pump 11 at the predetermined pressure level, and also by
controlling the solenoid switching valve 12, which switches and
operates the pump 11; the electro-pneumatic regulator 32, which
switches and operates the suction-side flow shut-off valve 13; and
the electro-pneumatic regulators 38 and 39, which operate the
discharge-side shutoff valve 14 and the suckback valve 15.
[0041] That is, when a command to begin the operation of the
chemical liquid supply system is generated, the controller 50 first
controls the electro-pneumatic regulator 32 to switch the
suction-side flow shut-off valve 13, shutting off the suction
passage 17a. This action cuts the pump 11 off from the resist
bottle 30. The controller 50 also switches the solenoid switching
valve 12 to supply operating air adjusted to the predetermined
pressure to the operating chamber 26 inside the pump 11. This
action causes the diaphragm 23 to move toward the pump chamber 25,
pressurizing the resist liquid R contained inside the pump chamber
25. Note that when the pump chamber 25 is not filled with the
resist liquid R, such as during the initial startup of the system,
the interior of the pump chamber 25 is pressurized. During this
process, the discharge passage 18a is shut off by the
discharge-side shutoff valve 14 on the downstream side of the pump
11, and therefore no resist liquid R is discharged.
[0042] Next, the controller 50 controls the electro-pneumatic
regulator 38 to switch the discharge-side shutoff valve 14, opening
the discharge passage 18a, and also controls the electro-pneumatic
regulator 39 to cancel the sucking-in of the resist liquid R by the
suckback valve 15. During this process, since the resist liquid R
inside the pump chamber 25 is pressurized by the diaphragm 23, the
resist liquid R is discharged from the pump 11, and a predetermined
amount of this resist liquid R is dripped onto a semiconductor
wafer from the nozzle 35a at the tip of the discharge pipe 35 via
the discharge passage 18a.
[0043] Next, the controller 50 controls the electro-pneumatic
regulator 38 to switch the discharge-side shutoff valve 14,
shutting off the discharge passage 18a. This action stops the
discharge of the resist liquid R from the nozzle 35a. The
controller 50 also controls the electro-pneumatic regulator 39 to
make the suckback valve 15 draw in a predetermined amount of the
resist liquid R, preventing unintended dripping of the resist
liquid R from the nozzle 35a.
[0044] Next, the controller 50 controls the electro-pneumatic
regulator 32 to switch the suction-side flow shut-off valve 13,
opening the suction passage 17a. This action connects the pump 11
to the resist bottle 30. The controller 50 also controls the
solenoid switching valve 12, opening the operating chamber 26 to
the atmosphere. Then, the operating air inside the operating
chamber 26 is discharged into the atmosphere, causing the diaphragm
23 to return to its original position. In this case, since the
resist bottle 30 is pressurized, based on the return of this
diaphragm 23, the resist liquid R is introduced into and fills the
pump chamber 25. From this point on, the controller 50 repeats the
aforementioned actions such that a predetermined amount of resist
liquid R is dripped onto each semiconductor wafer 37, as they are
fed in one after another.
[0045] Next, the characteristic effects of such an embodiment are
described.
[0046] In the pump unit 10 in the present embodiment, the
suction-side passage member 17 and the discharge-side passage
member 18 are assembled together onto the pump 11 (pump housings 21
and 22) such that the suction passages 17a and 21b as well as the
discharge passages 18a and 21c, connected to the pump chamber 25,
are disposed on the same line L1. That is, the fact that the
suction-side flow shut-off valve 13 is assembled onto the
suction-side passage member 17 and the discharge-side shutoff valve
14 is assembled onto the discharge-side passage member 18
eliminates the pipes and couplings that would be required for
connecting the pump 11 to the suction-side flow shut-off valve 13
and to the discharge-side shutoff valve 14, making the pump unit 10
small. As a result, the pump unit 10 can be disposed inside the
processing chamber, and the length of the tube downstream of the
pump 11 and the height from the pump to the nozzle (pump head) can
be made uniform for all individual processing chambers, thus
preventing variations in the discharge volume.
[0047] Moreover, the fact that the suction passages 17a and 21b, as
well as the discharge passages 18a and 21c, connected to the pump
chamber 25, are nearly linear and are disposed on the same line L1
nearly eliminates areas inside the chemical liquid passage of the
pump unit 10 where air bubbles or chemical liquid could become
trapped. This allows the air bubbles to be reliably expelled using
only a small purging volume and reduces chemical liquid
deterioration.
[0048] Furthermore, when the pump unit 10 is installed such that
the tip of the suction-side passage member 17 is pointed downward
while the discharge-side passage member 18 is pointed upward, thus
orientating the chemical liquid passage in the vertical direction,
the air bubbles inside the chemical liquid passage naturally move
toward the discharge side, making it possible to reliably expel
them. Therefore, the pump unit 10 in the present embodiment should
preferably be installed in such a manner.
[0049] Additionally, in the present embodiment, the inner
peripheral surfaces 33a and 34a of the seal rings 33 and 34 are
formed into a shape that is smoothly continuous with the inner
peripheral surfaces of the passages 17a, 21b, 18a, and 21c (a shape
in which the concave area gradually deepens toward the outside in
the radial direction as the distance from the passages 17a, 21b,
18a, and 21c toward the center of the seal rings 33 and 34 in their
thickness direction increases). This shape creates no acute-angled
dip between the seal rings 33 and 34 and the passages 17a, 21b,
18a, and 21c, and thus allows the resist liquid R to flow smoothly
in the areas of seal rings 33 and 34 and prevents the trapping of
the resist liquid R and air bubbles.
[0050] Furthermore, in the present embodiment, rod-shaped,
suction-side passage member 17 and discharge-side passage member 18
are disposed along the flat direction of the pump 11 (pump housings
21 and 22), which has a thin, flat shape. Moreover, the
suction-side flow shut-off valve 13 and discharge-side shutoff
valve 14 are disposed in the direction perpendicular to the passage
members 17 and 18, and along the flat direction of the pump
housings 21 and 22. When the rod-shaped, passage members 17 and 18
are disposed along the flat direction of the pump housings 21 and
22 in this way, the passage members 17 and 18 do not protrude in
the direction perpendicular to the flat direction. Additionally,
when the shut-off valves 13 and 14 are disposed in the direction
perpendicular to the passage members 17 and 18, and along the flat
direction of the pump housings 21 and 22, the open/close valves 13
and 14 do not protrude in the direction perpendicular to the flat
direction, nor do they significantly protrude in the flat
direction. As a result, the pump unit 10 can be made thin and
compact.
[0051] Furthermore, the structure in which the suckback valve 15
and the electro-pneumatic regulators 38 and 39 are also disposed
along the flat direction of the pump 11 also helps make the pump
unit 10 small (thin).
[0052] The suckback valve must be disposed on the downstream side
(the farthest downstream area of the chemical liquid passage) of
the discharge-side shutoff valve 14, and is more likely to be
disposed inside a processing chamber. In the present embodiment,
assembling the suckback valve 15 together with the discharge-side
passage member 18 eliminates the tubes and couplings that would be
required for connecting the suckback valve 15. The absence of these
tubes and couplings allows the pump unit 10 to be that much smaller
compared to a case in which the suckback valve 15 is separately
installed.
[0053] Additionally, in the present embodiment, when a space is
available near the pump unit 10 for disposing the electro-pneumatic
regulators 38 and 39 for controlling the operating air for
operating the discharge-side shutoff valve 14 and the suckback
valve 15, the electro-pneumatic regulators 38 and 39 can be
assembled into the pump unit 10, thus reducing the number of parts
to be attached to the chemical liquid supply system.
[0054] Note that the present invention is not limited to the
described contents of the aforementioned embodiment and may be
implemented in other ways, as in the following examples.
[0055] In the aforementioned embodiment, the pump 11 uses a
diaphragm 23. However, the pump may use a tube or bellows
instead.
[0056] In the aforementioned embodiment, the suction-side passage
member 17 and the discharge-side passage member 18 are assembled
onto the pump 11. However, it is also possible to form areas
equivalent to the suction-side passage member 17 and the
discharge-side passage member 18 integrally with the pump 11.
[0057] In the aforementioned embodiment, the electro-pneumatic
regulators 38 and 39 are assembled onto the discharge-side passage
member 18. However, these regulators may be provided separately.
Alternatively, the electro-pneumatic regulator 32 for operating the
suction-side flow shut-off valve 13 may be assembled onto the
suction-side passage member 17, for example.
[0058] In the aforementioned embodiment, the shut-off valves 13 and
14 and the suckback valve 15 are comprised of air-operated valves
that are operated by operating air. However, they may also be
comprised of solenoid-driven valves or motor-driven valves.
[0059] In place of the shutoff valve 14 in the aforementioned
embodiment, it is also possible to use an open/close valve that can
be adjusted to open/close at a relatively slow speed.
[0060] The suckback valve 15 used in the aforementioned embodiment
may be omitted.
[0061] In the aforementioned embodiment, the solenoid switching
valve 12 is switched to either connect the operating chamber 26 to
the supply tube 28 or open it to the atmosphere. However, the port
to be opened to the atmosphere may be connected to a negative
pressure generation source. Using negative pressure in this way
increases the suction force of the diaphragm 23 when the pump 11 is
sucking in the resist liquid R, making it possible to stop the
pressurization of the interior of the resist bottle 30 that was
done in the aforementioned embodiment.
[0062] In the aforementioned embodiment, an explanation is provided
using operating air as an example. However, it is also possible to
use another gas such as nitrogen in place of air.
[0063] In the aforementioned embodiment, an example using the
resist liquid R is described. This is because the target onto which
the chemical liquid is to be dripped is assumed to be a
semiconductor wafer 37. However, other chemical liquids and other
chemical liquid dripping targets may also be used.
* * * * *