US20070258837A1

US20070258837A1 - Pump Unit for Supplying Chemical Liquids

Info

Publication number: US20070258837A1
Application number: US11/662,019
Authority: US
Inventors: Katsuya Okumura; Kazuhiro Arakawa; Shigenobu Itoh
Original assignee: Individual
Current assignee: CKD Corp; Octec Inc
Priority date: 2004-09-10
Filing date: 2005-07-29
Publication date: 2007-11-08
Also published as: CN100562664C; JP2006077712A; JP4723218B2; KR20070114693A; CN101023269A; KR101118239B1; WO2006027909A1

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 17 a and 21 b and discharge passages 18 a and 21 c communicating with a pump chamber 25 are disposed on the same line L1.

Description

TECHNICAL FIELD

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

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.
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.
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.
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.
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

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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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

FIG. 1 is a frontal cross-sectional diagram illustrating the pump unit inside the chemical liquid supply system.
FIG. 2 (a) is a side cross-sectional diagram of the pump unit, and (b) is an enlarged cross-sectional diagram of (a).
FIG. 3 is a circuit diagram illustrating the entire circuitry of the chemical liquid supply system.

REFERENCE SYMBOLS

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; 17 a . . . suction passage; 18 . . . discharge-side passage member; 18 a . . . discharge passage; 21 and 22 . . . pump housing; 21 b . . . suction passage; 21 c . . . discharge passage; 25 . . . pump chamber; 33 and 34 . . . seal rings; 33 a and 34 a . . . inner peripheral surfaces; L1 . . . line; R . . . resist liquid.

PREFERRED EMBODIMENTS FOR THE INVENTION

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.
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.
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 21 a and 22 a, 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 21 a and 22 a 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.
A diaphragm 23 partitions the space formed by the concave sections 21 a and 22 a 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.
A suction passage 21 b, 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 21 b is connected to suction passage 17 a of the suction-side passage member 17. A discharge passage 21 c, which is connected to the pump chamber 25 and extends linearly upward, is also formed in the pump housing 21. Furthermore, this discharge passage 21 c is provided on the same line L1 as the suction passage 21 b. 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 21 b and discharge passage 21 c 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.
A supply/withdrawal passage 22 b, 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 22 b 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.
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 21 c. 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 21 b.
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 17 a, which extends nearly linearly downward, is formed in the suction-side passage member 17. This suction passage 17 a is disposed on the same line L1 as the suction passage 21 b 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 17 b is formed around the suction passage 17 a, and the seal ring 33 is housed inside the concave housing section 17 b. 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 17 a and 21 b from leaking out of the gap between the suction-side passage member 17 and the pump housing 21.
The inner peripheral surface 33 a of the seal ring 33 is smoothly continuous with the inner peripheral surfaces of the suction passages 17 a and 21 b. Specifically, the seal ring 33 has a shape in which the inner peripheral surface 33 a is continuous with the inner peripheral surfaces of the suction passages 17 a and 21 b, and in which the concave area gradually deepens toward the outside in the radial direction as the distance from the internal passages 17 a or 21 b 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 17 a and 21 b. This results in a shape that is not smoothly continuous with the inner peripheral surfaces of the passages 17 a and 21 b, 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.
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 17 a 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 13 a is opened to the atmosphere by the switching action of the electro-pneumatic regulator 32, the valve body 13 b of the suction-side flow shut-off valve 13 receives a spring force from a spring 13 c and shuts off the suction passage 17 a; when operating air is supplied to the supply/withdrawal chamber 13 a from the supply source 29, the valve body 13 b sinks by working against the spring force of the spring 13 c and opens the suction passage 17 a. Note that the part of the suction passage 17 a near the valve body 13 b is bent perpendicularly to the degree necessary for ensuring the reliable opening and closing action of the valve body 13 b (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.
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 18 a, which extends nearly linearly upward, is formed in the discharge-side passage member 18. This discharge passage 18 a is disposed on the same line L1 as the discharge passage 21 c 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 18 b is formed around the discharge passage 18 a, and a seal ring 34 is housed inside the concave housing section 18 b. 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 18 a and 21 c from leaking out of the gap between the discharge-side passage member 18 and the pump housing 21.
Like the aforementioned seal ring 33, the inner peripheral surface 34 a of the seal ring 34 is smoothly continuous with the inner peripheral surfaces of the discharge passages 18 a and 21 c, 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 35 a on its other end. The nozzle 35 a 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.
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 18 a 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 14 a is opened to the atmosphere by the switching action of the electro-pneumatic regulator 38, a valve body 14 b of the discharge-side flow shut-off valve 14 receives a spring force from a spring 14 c and shuts off the discharge passage 18 a; when operating air is supplied to the supply/withdrawal chamber 14 a from the supply source 29, the valve body 14 b sinks by working against the spring force of the spring 14 c and opens the discharge passage 18 a. Note that the part of the discharge passage 18 a near the valve body 14 b is bent perpendicularly to the degree necessary for ensuring the reliable opening and closing action of the valve body 14 b (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.
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 35 a, 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 15 a is opened to the atmosphere by the switching action of the electro-pneumatic regulator 39, a valve body 15 b of the suckback valve 15 sinks by receiving a spring force from a spring 15 c and enlarges the volume of the volume-expansion chamber 18 c connected in communication with the discharge passage 18 a, sucking in the predetermined amount of the resist liquid R into the volume-expansion chamber 18 c. In contrast, when operating air is supplied to the supply/withdrawal chamber 15 a from the supply source 29, the valve body 15 b protrudes by working against the spring force of the spring 15 c and reduces the volume of the volume-expansion chamber 18 c provided in the discharge passage 18 a.
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 14 a of the discharge-side shutoff valve 14 and the supply/withdrawal chambers 15 a 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 14 a of the discharge-side shutoff valve 14 and the supply/withdrawal chambers 15 a of the suckback valve 15, thereby operating the discharge-side shutoff valve 14 and the suckback valve 15.
In the pump unit 10 thus configured, the suction passage 17 a inside the suction-side passage member 17, the suction passage 21 b and the discharge passage 21 c inside the pump 11, and the discharge passage 18 a 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.
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.
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 17 a. 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 18 a 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.
Next, the controller 50 controls the electro-pneumatic regulator 38 to switch the discharge-side shutoff valve 14, opening the discharge passage 18 a, 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 35 a at the tip of the discharge pipe 35 via the discharge passage 18 a.
Next, the controller 50 controls the electro-pneumatic regulator 38 to switch the discharge-side shutoff valve 14, shutting off the discharge passage 18 a. This action stops the discharge of the resist liquid R from the nozzle 35 a. 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 35 a.
Next, the controller 50 controls the electro-pneumatic regulator 32 to switch the suction-side flow shut-off valve 13, opening the suction passage 17 a. 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.
Next, the characteristic effects of such an embodiment are described.
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 17 a and 21 b as well as the discharge passages 18 a and 21 c, 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.
Moreover, the fact that the suction passages 17 a and 21 b, as well as the discharge passages 18 a and 21 c, 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.
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.
Additionally, in the present embodiment, the inner peripheral surfaces 33 a and 34 a of the seal rings 33 and 34 are formed into a shape that is smoothly continuous with the inner peripheral surfaces of the passages 17 a, 21 b, 18 a, and 21 c (a shape in which the concave area gradually deepens toward the outside in the radial direction as the distance from the passages 17 a, 21 b, 18 a, and 21 c 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 17 a, 21 b, 18 a, and 21 c, 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.
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.
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).
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.
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.
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.
In the aforementioned embodiment, the pump 11 uses a diaphragm 23. However, the pump may use a tube or bellows instead.
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.
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.
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.
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.
The suckback valve 15 used in the aforementioned embodiment may be omitted.
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.
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.
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.

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.