U.S. patent application number 11/665969 was filed with the patent office on 2007-12-27 for pump for supplying chemical liquids.
This patent application is currently assigned to Octec Inc.. Invention is credited to Kazuhiro Arakawa, Shigenobu Itoh, Katsuya Okumura, Kazuhiro Sugata.
Application Number | 20070297927 11/665969 |
Document ID | / |
Family ID | 36227589 |
Filed Date | 2007-12-27 |
United States Patent
Application |
20070297927 |
Kind Code |
A1 |
Okumura; Katsuya ; et
al. |
December 27, 2007 |
Pump for Supplying Chemical Liquids
Abstract
An opening 22d of a supply/withdrawal passage 22b is positioned
at the center part of the internal wall surface 22c of the
operating chamber 26 (concave area 22a), and a cross-shaped venting
groove 22e extending from the opening 22d of the passage 22b to the
periphery of the wall surface 22c is formed in the wall surface
22c. Thus, an operating air in the chamber 26 is discharged
(sucked) through the passage 22b during drawing in the chemical
liquid. Since the opening 22d communicates with the venting groove
22e extending to the periphery of the chamber 26, if the center of
the diaphragm 23 covers the opening 22d first, the operating air in
the chamber 26 can be continuously evacuated (drew out) from the
venting groove 22e positioned on the outside of the center part
which first comes into contact with the opening 22d
Inventors: |
Okumura; Katsuya; (Tokyo,
JP) ; Itoh; Shigenobu; (Aichi, JP) ; Sugata;
Kazuhiro; (Aichi, JP) ; Arakawa; Kazuhiro;
(Aichi, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 320850
ALEXANDRIA
VA
22320-4850
US
|
Assignee: |
Octec Inc.
Tokyo
JP
CKD Corporation
Aichi
JP
|
Family ID: |
36227589 |
Appl. No.: |
11/665969 |
Filed: |
July 29, 2005 |
PCT Filed: |
July 29, 2005 |
PCT NO: |
PCT/JP05/13921 |
371 Date: |
April 20, 2007 |
Current U.S.
Class: |
417/437 |
Current CPC
Class: |
F04B 43/073
20130101 |
Class at
Publication: |
417/437 |
International
Class: |
F04B 43/073 20060101
F04B043/073 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 29, 2004 |
JP |
2004-316658 |
Claims
1. In a pump for supplying chemical liquids in which a pump chamber
and an operating chamber are divided by means of a diaphragm
comprised of a flexible film, the diaphragm deforms toward the pump
chamber when the interior of the pump chamber is pressurized using
an operating gas, thereby discharging the chemical liquid that has
been supplied into the pump chamber; and when the interior of the
operating chamber reaches a negative pressure because of the
withdrawal of the operating gas or when the interior of the
operating chamber is opened to the surrounding atmosphere, the
diaphragm deforms toward the operating chamber, thereby drawing a
chemical liquid into the pump chamber, and a supply/withdrawal
passage for supplying the operating gas to or withdrawing same from
the operating chamber is formed in the pump housing, and an opening
of the supply/withdrawal passage is provided in part of the
internal wall surface of the operating chamber, and a venting
groove that extends from the opening of the supply/withdrawal
passage to the periphery of the internal wall surface is formed on
the internal wall surface of the operating chamber.
2. The pump for supplying chemical liquids according to claim 1,
wherein the internal wall surface of the operating chamber is
circular in shape, and the opening of the supply/withdrawal passage
is positioned in the center of the internal wall surface of the
operating chamber.
3. The pump for supplying chemical liquids according to claim 1,
wherein the opening of the supply/withdrawal passage is positioned
in the center of the internal wall surface of the operating chamber
with the internal wall formed symmetrically from its center; and
the venting groove is formed to be symmetrical, with the center of
the opening of the supply/withdrawal passage at its center, in
correspondence with the internal wall surface of the operating
chamber.
4. The pump for supplying chemical liquids according to claim 1,
wherein the venting groove is linear in shape.
5. The pump for supplying chemical liquids according to claim 1,
wherein the venting groove is configured from continuous concave
areas obtained by forming a rough internal wall surface in the
operating chamber.
6. The pump for supplying chemical liquids according to any of
claim 5, wherein roughening of the internal wall surface of the
operating chamber is applied to the entire internal wall
surface.
7. The pump for supplying chemical liquids according to claim 1,
wherein the pump housing is formed to be thin in the deformation
direction of the diaphragm.
8. The pump for supplying chemical liquids according to claim 2,
wherein the venting groove is linear in shape.
9. The pump for supplying chemical liquids according to claim 2,
wherein the venting groove is configured from continuous concave
areas obtained by forming a rough internal wall surface in the
operating chamber.
10. The pump for supplying chemical liquids according to claim 9,
wherein roughening of the internal wall surface of the operating
chamber is applied to the entire internal wall surface.
Description
TECHNICAL FIELD
[0001] The present invention relates to a pump 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,
for example, a semiconductor manufacturing device.
BACKGROUND ART
[0002] 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 for supplying chemical
liquids such as that disclosed in Patent Document 1, for example,
is currently in use. This pump is divided by a diaphragm into a
pump chamber and an operating chamber (a pressurization chamber in
Patent Document 1), and driving the diaphragm by supplying air to
or withdrawing air from the operating chamber, via a
supply/withdrawal passage connected to the operating chamber,
changes the volume inside the pump chamber, thereby causing the
pump chamber to suction or discharge a chemical liquid.
[0003] When the pump chamber and the operating chamber are formed
to be thin and the pump is made thin through the use of a diaphragm
comprised of a flexible film, the diaphragm is secured at its
perimeter, and consequently tends to deform more at its center. At
the same time, to ensure efficient deformation of the entire
diaphragm, it has been preferable to position the opening of the
supply/withdrawal passage in the operating chamber in its
center.
[0004] When the interior of the operating chamber is evacuated in
order to draw the chemical liquid into the pump chamber or when the
interior of the operating chamber is opened to the surrounding
atmosphere in order to supply the pressurized chemical liquid, the
diaphragm begins to deform at its center toward the operating
chamber, with the result that the center tends to come into contact
with the internal wall of the operating chamber first. In such a
case, the center of the diaphragm blocks the opening of the
supply/withdrawal passage while the area surrounding the center of
the diaphragm does not contact the internal wall of the operating
chamber. This slows down the deformation of the diaphragm toward
the operating chamber, and moreover, may prevent the diaphragm from
deforming fully. As a result, it may take a long time for the
chemical liquid to fill the pump chamber or it may not be possible
to supply the pump chamber with the specified volume of chemical
liquid.
Patent document 1: Japanese patent application publication No.
2003-49778
DISCLOSURE OF THE INVENTION
[0005] A primary object of the present invention is to provide a
pump for supplying chemical liquids that can ensure quick and
reliable deformation of the diaphragm toward the operating chamber,
and that can shorten the time needed for filling the pump chamber
with a chemical liquid and ensure that the pump chamber is filled
with a sufficient volume of chemical liquid.
[0006] A pump for supplying chemical liquids according to the
present teaching is configured as described below. That is, in a
pump for supplying chemical liquids in which the pump chamber and
operating chamber are divided by means of a diaphragm comprised of
a flexible film, the diaphragm deforms toward the pump chamber when
the interior of the pump chamber is pressurized using an operating
gas, thereby discharging the chemical liquid that has been supplied
into the pump chamber; and when the interior of the operating
chamber reaches a negative pressure because of the withdrawal of
the operating gas or when the interior of the operating chamber is
opened to the surrounding atmosphere, the diaphragm deforms toward
the operating chamber, thereby drawing a chemical liquid into the
pump chamber, and
[0007] a supply/withdrawal passage for supplying the operating gas
to or withdrawing same from the operating chamber is formed in the
pump housing, and the opening of the supply/withdrawal passage is
provided in part of the internal wall surface of the operating
chamber, and
a venting groove that extends from the opening of the
supply/withdrawal passage to the periphery of the internal wall
surface is formed on the internal wall surface of the operating
chamber.
[0008] In this pump for supplying chemical liquids, the opening of
the supply/withdrawal passage is provided in part of the internal
wall surface of the operating chamber, and a venting groove is
formed, which extends from the opening of the supply/withdrawal
passage to the periphery of the interior wall surface. Here, when
the chemical liquid is to be drawn in, the operating gas inside the
operating chamber is evacuated (sucked out) through the
supply/withdrawal passage. In this case, the diaphragm tends to
deform from its center, which may cover the opening of the
supply/withdrawal passage first. However, the opening of the
supply/withdrawal passage is connected to the vent groove, which
opens toward the periphery of the operating chamber as described
above. Therefore, even when the diaphragm deforms from the center,
thus covering the opening of the supply/withdrawal passage first,
because the venting groove positioned on the outside of the
contacted center is open, it is possible to continue to evacuate
(draw out) the operating gas inside the operating chamber through
the open venting groove. In this way, even when such uneven
deformation occurs in the diaphragm, the diaphragm still quickly
and reliably deforms toward the operating chamber, shortening the
time needed for filling the pump chamber with the chemical liquid,
and filling the pump chamber with a sufficient volume of chemical
liquid.
[0009] Note that it is desirable to position the extension
destination of the venting groove as close as possible to the
periphery of the operating chamber, and it is best to extend it to
the periphery. With such a configuration, the diaphragm will not
block the venting groove until the diaphragm has sufficiently
deformed toward the operating chamber, ensuring reliable evacuation
(drawing out) of the operating gas from the operating chamber.
[0010] In a preferred embodiment of the pump for supplying chemical
liquids, the internal wall surface of the operating chamber is
circular in shape and the opening of the supply/withdrawal passage
is positioned in the center of the internal wall surface of the
operating chamber.
[0011] In this configuration, the fact that the opening of the
supply/withdrawal passage is positioned in the center of the
circular internal wall surface of the operating chamber allows the
operating gas to be efficiently supplied to or withdrawn from the
operating chamber.
[0012] In another preferred embodiment of the pump for supplying
chemical liquids, the opening of the supply/withdrawal passage is
positioned in the center of the internal wall surface of the
operating chamber, with the internal wall formed symmetrically from
its center; and the venting groove is formed to be symmetrical,
with the center of the opening of the supply/withdrawal passage at
its center, in correspondence with the internal wall surface of the
operating chamber.
[0013] In this configuration, the venting groove is formed to be
symmetrical from its center positioned at the center of the
internal wall surface of the operating chamber, where the opening
of the supply/withdrawal passage is positioned. Therefore, if,
while a chemical liquid is being drawn in, the center of the
diaphragm covers the opening of the supply/withdrawal passage
first, this venting groove maintains the interior of the operating
chamber at a stable negative pressure, enabling the diaphragm to
stably deform.
[0014] In either of the above configurations, the venting groove
should preferably have a linear shape.
[0015] Such a linear shape allows the venting groove to be easily
formed.
[0016] The venting groove can also be configured from continuous
concave areas obtained by forming a rough internal wall surface in
the operating chamber.
[0017] Configuring the venting groove from continuous concave areas
obtained by forming a rough internal wall surface in the operating
chamber allows the venting groove to be easily formed by simply
roughening the internal wall surface.
[0018] Note that the internal wall surface can be easily roughened
by means of shot blasting, that is, by blasting the surface with
abrasive grains.
[0019] Preferably, the entire internal wall surface of the
operating chamber should be roughened.
[0020] According to this configuration, the roughening of the
internal wall surface of the operating chamber is applied to the
entire internal wall surface, which corresponds to the deformation
region of the diaphragm. Thus, there is no need to separate the
internal wall surface of the operating chamber into an area that
should be roughened and an area that should not be roughened,
thereby simplifying the operation of roughening the internal wall
surface. Furthermore, the fact that the entire internal wall
surface of the operating chamber is roughened prevents the
diaphragm from blocking the venting groove until the diaphragm
deforms sufficiently toward the operating chamber, thus ensuring
reliable evacuation (drawing out) of the operating gas from the
operating chamber.
[0021] In either of the above configurations, the pump housing
should preferably be formed to be thin in the deformation direction
of the diaphragm.
[0022] When the pump housing is formed to be thin in the
deformation direction of the diaphragm, the operating chamber must
also be formed to be thin in the same direction. Since the
resulting structure tends to cause the center of the diaphragm to
contact the internal wall surface of the operating chamber first
during suctioning of a chemical liquid, the significance of
providing the venting groove is great.
BRIEF EXPLANATION OF DRAWINGS
[0023] [FIG. 1] is a frontal cross-sectional diagram illustrating
the pump unit inside the chemical liquid supply system.
[0024] [FIG. 2] (a) is a side cross-sectional diagram of the pump
unit, and (b) is an enlarged cross-sectional diagram of (a).
[0025] [FIG. 3] is a circuit diagram illustrating the entire
circuitry of the chemical liquid supply system.
[0026] [FIG. 4] (a) is the front view of the pump housing on the
operating chamber side, and (b) is a cross-sectional diagram along
line A-A in (a).
[0027] [FIG. 5] (a) and (b) are diagrams explaining the operation
of the diaphragm.
[0028] [FIG. 6] (a) is the front view of the pump housing on the
operating chamber side in another example, and (b) is a
cross-sectional diagram along line B-B in (a).
[0029] [FIG. 7] (a) and (b) are diagrams explaining the operation
of the diaphragm in another example.
EXPLANATION OF SYMBOLS
[0030] 22 . . . pump housing; 22b . . . supply/withdrawal passage;
22c . . . internal wall surface; 22d . . . opening; 22e . . .
venting groove; 22f . . . venting groove; 22g . . . concave area;
23 . . . diaphragm; 25 . . . pump chamber; 26 . . . operating
chamber; R . . . resist liquid (chemical liquid).
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0031] 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.
[0032] 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 discharge-side shut-off valve 14,
a suckback valve 15, a regulator 16, a suction-side passage member
17 and a discharge-side passage member 18.
[0033] The pump 11 has a thin flat prism form having a nearly
square shape when viewed from the front, and a pair of pump
housings 21 and 22. Concave areas 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 areas 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.
[0034] A diaphragm 23 partitions the space formed by the concave
areas 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 operation air for driving the diaphragm
23. Note that in order to reduce the thickness of the pump 11, the
pump housings 21 and 22 are made thin (in this case in the
deformation direction of the diaphragm 23), with the result that
both the pump chamber 25 and the operating chamber 26 form thin
spaces in the same direction.
[0035] 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 deformation
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.
[0036] 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. An opening 22d of the
supply/withdrawal passage 22b on the internal wall surface 22c of
the operating chamber 26 (concave area 22a) is positioned in the
center of the circular concave area 22a. Furthermore, as shown in
FIG. 4, a cross-shaped venting groove 22e, whose end extends to the
periphery of the operating chamber 26, is formed on the internal
wall surface 22c of the operating chamber 26, and the opening 22d
of the supply/withdrawal passage 22b is positioned in the
intersection of the cross-shaped venting groove 22e. This
supply/withdrawal passage 22b is then connected to a solenoid
switching valve 12 secured to the pump housing 22.
[0037] Here, the intake port of the solenoid switching valve 12 is
connected to one end of a supply tube 28 as shown in FIG. 3. The
supply tube 28 has an electro-pneumatic regulator 27 in the middle,
and the other end of the supply tube 28 is connected to a supply
source 29a. The electro-pneumatic regulator 27 is adjusted by a
controller 50, such that the pressure of the operating air supplied
from the supply source 29a to the pump 11 remains constant at a
preset value. The exhaust port of the solenoid switching valve 12
is connected to a vacuum generation source 29b via an exhaust pipe
28b. The solenoid switching valve 12 is controlled and switched by
the controller 50 to connect the operating chamber 26 to either the
supply source 29a or the vacuum generation source 29b. 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.
[0038] 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 evacuates the operating air out of the operating
chamber 26 and the pressure inside the operating chamber 26 becomes
negative, the diaphragm 23, which has been pushed to the pump
chamber 25 side, moves toward the operating chamber 26, introducing
the resist liquid R from the upstream side into the pump chamber 25
via the suction passage 21b.
[0039] Here, during suctioning of the resist liquid R, the
diaphragm 23 deforms to its maximum deformation position to contact
the internal wall surface 22c of the operating chamber 26, as shown
in FIG. 5 (a). During this deformation, the diaphragm 23 tends to
deform at its center, as shown in FIG. 5 (b), such that its center
may cover the opening 22d of the supply/withdrawal passage 22b
before the diaphragm 23 deforms to its maximum deformation
position. In this case, the opening 22d is connected to the venting
groove 22e, which extends to the periphery of the operating chamber
26. Consequently, even when the diaphragm 23 deforms from the
center, thus the center covers the opening 22d of the
supply/withdrawal passage 22b first, the venting groove 22e
positioned on the outside of the contacted center is open.
Therefore, it is possible to continue to evacuate the interior of
the operating chamber 26 through the open venting groove 22e (the
arrow in FIG. 5 (b) indicates the flow of the operating air). As a
result, even when such uneven deformation occurs in the diaphragm
23, the diaphragm 23 still reliably deforms to its maximum
deformation position within a short period, thus shortening the
time needed for filling the pump chamber 25 with the resist liquid
R and ensuring a sufficient charging volume.
[0040] A 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.
[0041] 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, preventing 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.
[0042] The suction-side shut-off valve 13 consisting of an
air-operated valve is assembled together with the suction-side
passage member 17. The suction-side 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 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 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 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 29a, the valve
body 13b sinks by working against the spring force of the spring
13c to open 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.
[0043] 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.
[0044] 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 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.
[0045] A discharge-side shut-off valve 14 consisting of an
air-operated valve is assembled together with the discharge-side
passage member 18. The discharge-side 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 shut-off valve 14 is
constructed in the same way as the aforementioned suction-side
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 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 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 29a, the valve
body 14b sinks by working against the spring force of the spring
14c to open 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.
[0046] 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 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, reducing the
volume of the volume-expansion chamber 18c provided in the
discharge passage 18a.
[0047] 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 shut-off 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 shut-off 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 shut-off 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 shut-off valve 14 and the supply/withdrawal chambers
15a of the suckback valve 15, thereby operating the discharge-side
shut-off valve 14 and the suckback valve 15.
[0048] 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 linear in shape 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.
[0049] 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 shut-off valve 13; and the
electro-pneumatic regulators 38 and 39, which operate the
discharge-side shut-off valve 14 and the suckback valve 15.
[0050] 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 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. During this
process, the discharge passage 18a is shut off by the
discharge-side shut-off valve 14 on the downstream side of the pump
11, preventing discharge of the resist liquid R.
[0051] Next, the controller 50 controls the electro-pneumatic
regulator 38 to switch the discharge-side shut-off 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, the
resist liquid R inside the pump chamber 25, pressurized by the
diaphragm 23, 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.
[0052] Next, the controller 50 controls the electro-pneumatic
regulator 38 to switch the discharge-side shut-off 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
cause the suckback valve 15 to draw in a predetermined amount of
the resist liquid R, preventing unintended dripping of the resist
liquid R from the nozzle 35a.
[0053] Next, the controller 50 controls the electro-pneumatic
regulator 32 to switch the suction-side shut-off valve 13, opening
the suction passage 17a. This action connects the pump 11 to the
resist bottle 30. The controller 50 also switches the solenoid
switching valve 12, causing the operating air to be suctioned from
the operating chamber 26 by means of the vacuum generation source
29b. Then, the pressure inside the operating chamber 26 becomes
negative, with the result that the diaphragm 23 deforms to its
maximum deformation position to contact the internal wall surface
22c of the operating chamber 26 and the resist liquid R is
suctioned into and fills the pump chamber 25.
[0054] During this suctioning, if the center of the diaphragm 23
first covers the opening 22d of the supply/withdrawal passage 22b,
the opening 22d is connected to the venting groove 22e, which
extends to the periphery of the operating chamber 26, causing the
evacuation of the interior of the operating chamber 26 to continue
through the venting groove 22e positioned on the outside of the
center that is contacted first. Therefore, even when such uneven
deformation occurs in the diaphragm 23, the diaphragm 23 can
reliably deform to its maximum deformation position within a short
period, thus shortening the time needed for filling the pump
chamber 25 with the resist liquid R and ensuring a sufficient
charging volume. 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
carried in one after another.
[0055] Next, the characteristic effects of such an embodiment are
described.
[0056] In the present embodiment, the opening 22d of the
supply/withdrawal passage 22b is positioned in the center of the
internal wall surface 22c of the operating chamber 26 (concave area
22a), and the cross-shaped venting groove 22e, which extends from
the opening 22d of the supply/withdrawal passage 22b toward the
periphery of the internal wall surface 22c, is formed on the
internal wall surface 22c. During suctioning of the resist liquid
R, the operating air the operating chamber 26 is evacuated through
the supply/withdrawal passage 22b. In this case, the diaphragm 23
tends to deform in its center, which may cover the opening 22d of
the supply/withdrawal passage 22b first. However, in the present
embodiment, the opening 22d of the supply/withdrawal passage 22b is
connected to the venting groove 22e, which opens toward the
periphery of the operating chamber 26. Therefore, even when the
diaphragm 23 deforms in this manner, the venting groove 22e
positioned on the outside of the contacted center is open, making
it possible to continue to evacuate the operating air inside the
operating chamber 26 through the open venting groove. As a result,
even when such uneven deformation occurs in the diaphragm 23, the
diaphragm 23 can reliably deform to its maximum deformation
position toward the operating chamber 26 within a short period,
thus shortening the time needed for filling the pump chamber 25
with the resist liquid R and ensuring a sufficient charging
volume.
[0057] In the present embodiment, the fact that the opening 22d of
the supply/withdrawal passage 22b is positioned in the center of
the circular internal wall surface 22c of the operating chamber 26
allows the operating air to be efficiently supplied to or withdrawn
from the operating chamber 26.
[0058] In the present embodiment, since the venting groove 22e
extends to the periphery of the operating chamber 26, the diaphragm
23 can be prevented from blocking the venting groove 22e until the
diaphragm 23 deforms sufficiently toward the operating chamber 26,
thus ensuring reliable evacuation of the operating air inside the
operating chamber 26.
[0059] In the present embodiment, the venting groove 22e is formed
in a symmetric cross shape, with its center positioned at the
center of the internal wall surface 22c of the circular operating
chamber 26 (concave area 22a), which has a symmetric shape.
Therefore, during suctioning of the resist liquid R, even if the
center of the diaphragm 23 covers the opening 22d of the
supply/withdrawal passage 22b first, the venting groove 22e
maintains the pressure inside the operating chamber 26 at a stable
negative pressure, enabling the diaphragm 23 to stably deform.
[0060] In the present embodiment, the venting groove 22e is
designed to have a linear shape, which allows it to be easily
formed.
[0061] In the present embodiment, since the pump housing 22 is
formed to be thin in the deformation direction of the diaphragm 23
in order to make the pump 11 thin, the operating chamber 26 is also
formed to be thin in the same direction. Because the resulting
structure tends to cause the center of the diaphragm 23 to contact
the internal wall surface 22c of the operating chamber 26 first
during suctioning of the resist liquid R, the significance of
providing the venting groove 22e is great.
[0062] 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.
[0063] In the aforementioned embodiment, the cross-shaped venting
groove 22e is formed on the internal wall surface 22c of the
operating chamber 26 (concave area 22a). However, the shape of the
venting groove is not limited to such a shape. Although the venting
groove 22e has a cross shape that extends in all four directions
from the opening 22d, it can also have a Y shape that extends in
three directions, for example. The venting groove may also have a
shape that extends in any other odd or even number of directions.
Note that when changing the shape of the venting groove, it is
desirable to position the venting groove as close as possible to
the periphery of the operating chamber, and it is best to extend
the venting groove to the periphery of the operating chamber 26
(concave area 22a) as in the aforementioned embodiment.
[0064] Furthermore, as indicated by the dots in FIG. 6, it is also
possible to form the entire internal wall surface 22c of the
operating chamber 26 as a rough surface, and configure a venting
groove 22f with continuous individual concave areas 22g obtained by
roughening the surface, as indicated by the dash line in FIG. 7
(b). With such a configuration, even when the center of the
diaphragm 23 covers the opening 22d of the supply/withdrawal
passage 22b first during suctioning of the resist liquid R as shown
in FIG. 7 (a), the opening 22d is connected to the venting groove
22f, which extends to the periphery of the operating chamber 26 as
the continuation of the concave areas 22g. This allows the
evacuation of the interior of the operating chamber 26 to continue
through the venting groove 22f, which is positioned on the outside
of the contacted center. (In FIG. 7 (b), the arrow indicates the
flow of the operating air.) Such a configuration also provides
similar effects to those provided by the embodiment described
above.
[0065] Note that the internal wall surface 22c can be easily
roughened by means of shot blasting, that is, by blasting the
surface with abrasive grains. Moreover, since the entire internal
wall surface 22c is roughened, there is no need to mask an area of
the internal wall surface 22c that should not be roughened, thus
simplifying the operation of roughening the internal wall surface
22c.
[0066] In the aforementioned embodiment, the opening 22d of the
supply/withdrawal passage 22b is positioned at the center of the
operating chamber 26 (concave area 22a), but it can also be offset
from the center.
[0067] In the aforementioned embodiment, the pressure inside the
operating chamber 26 is set to be negative during suctioning of the
resist liquid R. However, the operating chamber 26 can also be
opened to the surrounding atmosphere. In this case, the interior of
the resist bottle 30, for example, must be pressurized.
[0068] In the aforementioned embodiment, the pump unit 10 is
comprised of the pump 11, which acts as a pump for supplying
chemical liquids and into which shut-off valves 13 and 14, the
suckback valve 15, or the like are integrated. However, other
configurations that have at least the pump 11 body can also be
used.
[0069] 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.
[0070] 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.
* * * * *