JP2000156338A - Substrate treating device and trap tank used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate treating device which can accurately detect the remaining amount of a treating solution in a trap tank. SOLUTION: An optical sensor 18 is attached to a flow passage section 15 communicating a branch section 30 from which an injection port 13 and a discharge port 14 are branched off with a solution reservoir section 16 in which a treating solution is reserved. When the quantity of the treating solution contained in a trap tank decreases due to substrate treatment, the surface level of the treating solution in the flow passage section 15 gradually descends. The optical sensor 18 detects that the treating solution in the section 15 runs low when the surface level of the solution becomes lower than its position. Since the treating solution remains in the solution reservoir section 16, the substrate treatment can be performed continuously by using the remaining amount of the solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a photoresist liquid on a substrate such as a semiconductor substrate or a glass substrate for liquid crystal display.
The present invention relates to a substrate processing apparatus including a trap tank in which a processing liquid such as an SOG liquid (Spin On Glass: silica-based film forming material) is temporarily stored before being supplied to a substrate.

[0002]

2. Description of the Related Art Conventionally, a processing liquid such as a photoresist liquid or an SOG liquid is supplied from a processing liquid supply tank to a substrate processing apparatus that supplies a processing liquid to a substrate such as a semiconductor substrate and performs predetermined processing on the substrate. There is provided a trap tank for temporarily storing the treated liquid, and thereafter supplying the treated liquid to the substrate. By providing a trap tank, when the processing liquid in the processing liquid supply tank runs out, the remaining substrate liquid in the trap tank is used to continuously process the substrate remaining on the substrate processing apparatus. Also, the processing efficiency is improved by not stopping the substrate processing even during the replacement of the processing liquid supply tank. For detecting the remaining amount of the processing liquid, a capacitance sensor attached to a processing liquid supply tank or a trap tank is used. The capacitance sensor detects a change in capacitance according to the remaining amount of the processing liquid remaining in the tank.

[0003]

However, the prior art having such a structure has the following problems. In recent years, various processing liquids have been used for processing substrates, and the processing liquids have different dielectric constants. Therefore, even if the remaining amount is the same, the capacitance will be different if the type of the processing liquid is different. Therefore, there is a problem that it is difficult to accurately detect the remaining amount for each processing solution.

Further, with the recent miniaturization of circuit patterns formed on semiconductor substrates and multi-layer wiring, in order to efficiently form an interlayer insulating film having relatively high flatness, an SOG solution is required.
(Spin on glass: a silica-based film forming material) and the like are beginning to be used. A processing liquid such as an SOG liquid for forming such an interlayer insulating film has a characteristic of being easily crystallized. Therefore, when using a processing liquid that easily crystallizes, such as an SOG liquid, the upper or lower surface of the liquid pool where the processing liquid is stored and the side surface are substantially perpendicular to each other, and the processing liquid in the processing liquid pool is If a conventional trap tank in which a dead water area in which the processing liquid stays when flowing is used, there is also a problem that the processing liquid crystallizes in the trap tank.

The present invention has been made in view of such circumstances, and a substrate processing apparatus and a substrate processing apparatus capable of accurately detecting the remaining amount of a processing liquid in a trap tank regardless of the type of the processing liquid. It is intended to provide a trap tank to be used.

[0006]

The present invention has the following configuration in order to achieve the above object. Claim 1
The invention described in (1) is a substrate processing apparatus that performs processing on a substrate by supplying a processing liquid to a substrate from a trap tank having a liquid storage portion in which a processing liquid that has been sent is temporarily stored. A remaining amount detecting means for detecting a remaining amount of the processing liquid, wherein the remaining amount detecting means is a flow path connecting the inlet for injecting the sent processing liquid into the trap tank and the liquid reservoir; It is an optical sensor for detecting the presence or absence of a processing liquid in the inside.

According to a second aspect of the present invention, in the substrate processing apparatus according to the first aspect, the apparatus further includes a discharge path connected to the trap tank for discharging gas in the liquid reservoir. An opening / closing valve that opens and closes, an optical sensor that detects the presence or absence of a processing liquid in a discharge path from the trap tank to the opening / closing valve, and a valve control unit that closes the opening / closing valve when the optical sensor detects a processing liquid. It is provided.

According to a third aspect of the present invention, there is provided a trap tank having a liquid reservoir portion for temporarily storing a processing liquid sent thereto, wherein the trap tank communicates with the liquid reservoir portion at one end side and at least a part of a side wall. Is branched into a flow path portion made of a material that transmits light, and the other end side of the flow path portion into an inlet for injecting the processing liquid and an outlet for discharging gas in the liquid reservoir. The liquid reservoir has a tapered shape in which the upper portion is tapered upward and communicates with the flow channel portion at the upper end position, while the lower portion has a tapered shape which is reduced downward. And a delivery port for delivering the processing liquid is provided at the lower end position.

[0009]

The operation of the present invention is as follows. According to the first aspect of the present invention, the processing liquid sent to the trap tank is injected from the injection port, flows through the flow path, and flows into the liquid reservoir. The inflowing processing liquid is stored in the liquid storage part. The substrate processing apparatus supplies the processing liquid stored in the liquid pool to the substrate. The optical sensor, which is the remaining amount detecting means, detects the processing liquid while the processing liquid is flowing in the flow path of the trap tank, and when the processing liquid is no longer injected from the inlet, the processing liquid flows to the substrate. Since the processing liquid in the flow path runs out earlier than the inside of the liquid pool part according to the supply, it is detected that the processing liquid has run out in a state where the processing liquid is stored in the liquid pool part. The substrate processing apparatus can continuously perform the substrate processing by supplying the processing liquid remaining in the liquid reservoir of the trap tank to the substrate even after the processing liquid is no longer supplied to the trap tank.

According to the second aspect of the present invention, when the discharge passage for discharging gas in the liquid reservoir of the trap tank is opened by the opening / closing valve, the processing liquid supplied to the trap tank is used to discharge the gas into the liquid reservoir. Is discharged from the trap tank. At this time, when all the gas in the trap tank is discharged, the processing liquid flows into the discharge path. Since the optical sensor is provided in the discharge path between the open / close valve and the trap tank, it detects that the processing liquid has flowed into the discharge path before the processing liquid reaches the open / close valve. When the optical sensor detects the processing liquid in the discharge path, the valve control means determines that the gas in the trap tank has been discharged, and closes the open / close valve. This allows
The processing liquid is prevented from flowing to a discharge path outside the on-off valve.

According to the third aspect of the invention, the processing liquid injected from the injection port of the trap tank flows through the flow path and flows into the liquid pool. The gas flowing in with the processing liquid, or bubbles in the processing liquid, which is a gas generated from the processing liquid, are guided into the flow path by the tapered upper portion that becomes smaller above the liquid reservoir,
It passes through the inside of the flow path part and is guided to the discharge port of the branch part. On the other hand, the processing liquid in the liquid pool is sent out from the outlet without staying in the liquid pool by the tapered lower portion that becomes smaller downward. Since at least a part of the side wall of the flow path has permeability, by detecting the presence or absence of the processing liquid in the permeable portion, it becomes easy to detect the remaining amount of the processing liquid in the trap tank.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram illustrating a schematic configuration of a substrate processing apparatus according to an embodiment. As the substrate processing apparatus according to the present invention, for example, a so-called SOG liquid which is a polymer-based processing liquid such as BCB (benzocyclobutene), a silica-based processing liquid such as HSQ (hydrogensilsesquioxane), or a photoresist. There are a coating apparatus that applies a processing liquid such as a liquid to the substrate to apply the processing liquid to the substrate, and a developing apparatus that supplies a developing liquid to the substrate to perform development.

The substrate processing apparatus shown in FIG. 1 includes a spin chuck 3 which holds a substrate W by suction and rotates in a horizontal plane. The spin chuck 3 is attached to an upper end of a rotating shaft 2 that rotates around a vertical axis by driving the electric motor 1 and is connected to a vacuum line (not shown). Above the spin chuck 3, a nozzle 4 for supplying a processing liquid onto the substrate W is provided. Around the spin chuck 3, a scatter prevention cup 5 for receiving the processing liquid scattered by the rotation of the substrate W is provided, and the scatter prevention cup 5 receives the processing liquid scattered from the substrate W. A collecting drain 5a for collecting and an exhaust port 5b for exhausting the inside of the scattering prevention cup 5 are provided.

The processing liquid supplied onto the substrate W is configured to be sent from a processing liquid tank 10, and a pressure line (not shown) for pressurizing the inside of the tank is connected to the processing liquid tank 10. I have. The processing liquid tank 10 sends out the processing liquid in the processing liquid tank 10 to the liquid sending line 11 by being pressurized with, for example, nitrogen gas from a pressurizing line.
The other end of the liquid sending line 11 is connected to an inlet 13 of a trap tank 12 where the processing liquid temporarily accumulates before the processing liquid is supplied to the substrate W.

The trap tank 12 has a liquid reservoir 16 for storing the processing liquid, a flow path 15 having one end communicating with the liquid storage 16, and an inlet for injecting the processing liquid into the other end of the flow path 15. A branch portion 30 is provided for branching into a discharge port 13 for discharging the gas in the trap tank 12.
A liquid feed line 11 is connected to the inlet 13, and the processing liquid sent from the processing liquid tank 10 is injected into the trap tank 12 from the inlet 13. The outlet 14 has a drain line 2 for discharging gas injected together with the processing liquid injected from the inlet 13 and gas generated from the processing liquid from the trap tank 12.
0 is connected for communication. The drain line 20 corresponds to a discharge path in the present invention.

A drain-side optical sensor 21 for detecting a processing liquid entering the drain line 20 is attached to the drain line 20 connected to the discharge port 14. When the processing liquid is detected by the optical sensor 21 on the drain side, the control unit 6 described later controls the drain line 2.
The opening / closing valve 22 for opening / closing 0 is configured to be closed. Further, the terminal side of the drain line 20 is maintained in an inert gas atmosphere (for example, a nitrogen atmosphere) by an inert gas supply unit (not shown). This allows
It is possible to prevent crystallization of the processing liquid due to an air atmosphere flowing into the drain line 20 or the trap tank 12 from the end side of the drain line 20.

The channel portion 15 provided with the branch portion 30 has a tubular shape communicating the branch portion 30 to the liquid reservoir 16 in order to guide the processing liquid injected from the inlet 13 to the liquid reservoir 16. The entire flow path section 15 is formed of a material that transmits light (has transmissivity). An optical sensor 18 on the tank side is attached to the outside of the flow path section 15, and the presence or absence of the processing liquid in the flow path section 15 is detected by the optical sensor 18 on the tank side.

A liquid reservoir 16 with which the flow path 15 communicates.
The upper portion 16a has a tapered shape (for example, an upward conical shape) in which the upper portion 16a decreases upward, and the lower portion 16b has a taper shape (for example, a downward conical shape) in which the lower portion 16b decreases. Are formed in a cylindrical shape. A flow path 15 is communicated with an upper end position of the upper portion 16a, and an outlet 17 for sending out the processing liquid in the liquid reservoir 16 to the nozzle 4 is provided at a lower end position of the lower portion 16b. With this configuration,
The gas flowing into the liquid reservoir 16 together with the processing liquid and the bubbles generated by the gas generated from the processing liquid rise while being guided by the tapered upper portion 16a that becomes smaller upward, and enter into the flow path portion 15. Sent. Further, the bubble rises in the flow path portion 15 and is guided to the outlet 14. Therefore, it is possible to prevent the processing liquid containing bubbles from being supplied to the substrate W. On the other hand, when the processing liquid filled in the liquid reservoir 16 is sent out from the outlet 17,
Since the upper portion 16a has a tapered shape that becomes smaller upward, and the lower portion 16b has a tapered shape that becomes smaller downward, the flow of the processing liquid occurs in the entire liquid pool portion 16. In other words, in the liquid pool 16, no dead water area is generated due to the stagnation of the processing liquid, and the liquid pool 16
The processing liquid in the inside can be sequentially supplied to the substrate W. As a result, crystallization in the trap tank 12 can be prevented even when a processing solution that easily crystallizes is used.

As shown in FIG. 2, the light sensor 18 on the tank side includes a light projecting element 18a for projecting light and a light receiving element for receiving the reflected light by reflecting the projected light on a predetermined surface. And a reflection type optical sensor having the element 18b. More specifically, the light sensor 18 on the tank side detects the light emitted from the light emitting element 18 a
It is mounted so that it is received by the light receiving element 18b when reflected by 5a. The light receiving element 18a is provided on the inner wall surface 1
By receiving the reflected light reflected at 5a, an electric signal is generated by, for example, a photoelectric effect. The drain-side optical sensor 21 has the same configuration.

The optical sensor 18 on the tank side operates as follows. For example, assuming that the refractive index of the material of the channel portion 15 to which the optical sensor 18 is attached is larger than the refractive index of the gas, the inside of the channel portion 15 is filled with the gas as shown in FIG. If there is, the material of the flow path 15 and the flow path 1
Due to the difference in the refractive index from that of the gas in the flow path 5, the light projected from the light projecting element 18a does not enter the flow path 15
5 is reflected by the inner wall surface 15a. When receiving the light reflected by the inner wall surface 15a, the light receiving element 18b generates an electric signal by a photoelectric effect. That is, the optical sensor 18 detects that there is no processing liquid in the flow path unit 15 by generating an electric signal. On the other hand, as shown in FIG. 3B, when the inside of the flow path 15 is filled with the processing liquid, the material of the flow path 15 and the refractive index of the processing liquid in the flow path 15 are almost equal. Since they are equivalent, the light emitted from the light emitting element 18a does not reflect on the inner wall surface 15a of the flow path unit 15, but passes through the processing liquid in the flow path unit 15 and goes out of the flow path unit 15. Go through.
At this time, since the light receiving element 18b does not receive the reflected light,
Do not generate electrical signals. That is, the optical sensor 18 detects the presence of the processing liquid in the flow path unit 15 by not generating an electric signal. The drain-side optical sensor 21
Operates similarly for the drain line 20.

The control unit 6 is composed of a computer including a CPU, a memory, and the like (not shown).
In accordance with a predetermined program, the electric motor 1 is driven to rotate, and the nozzle 4 and the scattering prevention cup 5 are driven to move up and down. The control unit 6 constantly monitors the presence or absence of an electric signal from the optical sensor 18 on the tank side. When the processing liquid in the flow path unit 15 runs out, the control unit 6 operates an alarm unit (not shown) to activate the substrate processing apparatus. Of the processing liquid tank 10 is urged. Further, the control unit 6 opens the opening / closing valve 22 in accordance with an instruction from the input unit 7 operated by the operator, and the light sensor 21 on the drain side.
When the processing liquid is detected in step (1), the opening / closing valve 22 is closed. Note that the control unit 6 corresponds to a valve control unit in the present invention.

Hereinafter, detection of the remaining amount of the processing liquid in the trap tank 12 and so-called air bleeding in the trap tank 12 will be described. The processing liquid sent from the processing liquid tank 10 fills the entirety of the trap tank 12, that is, the branch portion 30, the flow path portion 15, and the liquid pool portion 16. At this time, the inside of the drain line 20 communicatively connected to the outlet 14 of the branch portion 30 is also filled with the processing liquid up to the position of the optical sensor 21 on the drain side by the operation described later of the opening / closing valve 22.

The processing liquid in the trap tank 12 is sent to the nozzle 4 through the supply line 19 to perform the substrate processing.
As the processing of the substrate W proceeds, the processing liquid is consumed, the processing liquid in the processing liquid tank 10 becomes empty, and the liquid level of the processing liquid in the flow path portion 15 of the trap tank 12 gradually decreases. When the liquid level falls below the optical sensor 18 on the tank side, an electric signal is generated from the optical sensor 18 on the tank side. The control unit 6 detects the electric signal and issues an alarm to urge the operator to replace the processing liquid tank 10. Even after the alarm is issued, the processing of the substrate W is continued because a predetermined amount of the processing liquid remains in the trap tank 12.

On the other hand, when the replacement of the processing liquid tank 10 is completed, the operator operates the input unit 7 to discharge the gas in the trap tank 12 and gives an instruction to the control unit 6 to start air bleeding. The control unit 6 opens the opening / closing valve 22 according to this instruction. Thereby, the gas in the trap tank 12 escapes through the drain line 20. When all the gas has escaped from the trap tank 12, the processing liquid flows into the drain line 20 next. This treatment liquid travels along the drain line 20 and reaches the position of the optical sensor 21 on the drain side. Here, the light sensor 21 on the drain side is
The processing liquid in the drain line 20 is detected. Control unit 6
Closes the on-off valve 22 when the processing liquid in the drain line 20 is detected. Thus, the processing liquid does not reach the open / close valve 22 and stops in the drain line 20 before the open / close valve 22.

Therefore, according to the above-described apparatus, the tubular flow path 15 is provided between the branch section 30 and the liquid pool section 16, and the presence or absence of the processing liquid in the flow path section 15 is detected by the optical sensor 18. Therefore, the remaining amount of the processing liquid in the trap tank 12 can be accurately detected from the liquid level in the flow path section 15 that decreases as the processing liquid decreases. In addition, the trap tank 12 having the above-described shape can use the trap tank even with a processing liquid such as an SOG liquid that is easily crystallized. Further, since the end of air release is detected by the optical sensor 21 and the processing liquid in the drain line 20 does not pass through the opening / closing valve 22, contamination of particles or the like due to crystallization of the processing liquid is prevented, and the cost is high. It is possible to prevent the processing liquid from being wasted.

Further, the trap tank 1 of the present invention
The specific configuration of No. 2 will be described in detail with reference to FIG. As described above, the trap tank 12 is roughly composed of the branch part 30, the flow path part 15, and the liquid pool part 16. Specifically, as shown in FIG. 4, the trap tank 12 is
1, a tube 42 that is the flow path section 15, and a liquid pool section 1
6, a top body 43 and a bottom body 44.

The branch tube 41 is formed in a three-pronged shape in which an inlet 13, an outlet 14, and an insertion port 51 of the tube 42 are formed. Liquid feed line 1
1, a drain line 20 is inserted into the outlet 14, respectively, and nuts 52, 53 (shown by two-dot chain lines in the figure)
Fixed by One end of the tube 42 is fixed to the insertion port 51 by a nut 54. Thus, the branch tube 41 and the tube 42 are detachably connected to each other.

The tube 42 is entirely made of a transparent material, and has a branch tube 4 inside.
A flow path for communicating from 1 to the top body 43 is provided. More specifically, for example, the tube diameter is about 12 mm, and the material is formed of PFA (tetrafluoroethylene-perfluoroalkylvinyl ether copolymer). The other end of the tube 42 has a liquid reservoir 1
6, the top body 43 and the bottom body 44 are connected to each other.

The liquid reservoir 16 includes a top body 43,
Bottom body 44 is fitted and constituted. The top body 43 has an opening at the fitting surface with the bottom body 44, and is formed in a tapered shape in which an upper part 16a on the inner side is reduced upward, and a tube 42 is connected to an upper end position of the upper part 16a. Connection port 56 is formed. The other end of the tube 42 is fixed to the connection port 56 by a nut 55, and the liquid reservoir 16 and the tube 42 are removably connected to each other. The bottom body 44 also has an opening at the fitting surface with the top body 43, and a lower portion 16b inside the lower body 16 is formed in a tapered shape so as to decrease downward, and a supply line 19 is provided at a lower end position of the lower portion 16b. The outlet 17 to which is connected is formed. A supply line 19 for supplying the processing liquid to the substrate W is detachably fixed to the delivery port 17 by a nut 57.

According to the configuration of the trap tank 12,
Since the tube 42 for attaching the optical sensor is configured to be detachable, the tube 42 can be easily replaced when the permeability deteriorates due to being attacked by the processing liquid or the like. Also, not only the tube 42,
Since the branch tube 41, the top body 43, and the bottom body 44 are each configured to be detachable, it is possible to easily replace each part.

The present invention can be modified as follows. (1) In the substrate processing apparatus of the above-described embodiment, the entire flow path portion 15 (tube 42) of the trap tank 12 is formed of a material having permeability. However, the present invention is not limited to this. For example, it is also possible to make only a part of the flow path portion 15 a material having permeability. Further, the entire trap tank 12 may be formed of a material having transparency.

(2) In the substrate processing apparatus of the above-described embodiment, a reflection type optical sensor has been described.
The present invention is not limited to this, and may be a transmission type optical sensor.

(3) In the substrate processing apparatus of the above-described embodiment, the upper portion 16a of the liquid reservoir 16 of the trap tank 12
Has been described in a tapered shape in which the lower portion 16b is formed in a downwardly tapered shape, but the present invention is not limited to this.
For example, the upper portion 16a is formed in a tapered polygonal pyramid shape that becomes smaller upward, the flow path portion 15 (tube 42) communicates with the upper end position, and the lower portion 16b is formed in a tapered polygonal pyramid shape that becomes smaller downward. However, the outlet 17 may be formed at the lower end position.

[0034]

As apparent from the above description, the present invention has the following effects. That is, according to the first aspect of the present invention, since the presence or absence of the processing liquid in the flow path is detected by the optical sensor, it is possible to accurately detect the processing liquid regardless of the type of the processing liquid. In addition, since the presence or absence of the processing liquid in the flow path on the upstream side of the liquid pool is detected, even after the processing liquid is no longer supplied to the trap tank, the substrate processing is performed by the processing liquid remaining in the liquid pool. Can continue.

According to the second aspect of the present invention, when the gas in the trap tank is discharged, the processing liquid can be prevented from being discharged together with the gas. It is possible to prevent the occurrence of contamination of the particles and the like, thereby suppressing waste of the processing liquid.

According to the third aspect of the present invention, since the processing liquid does not stay in the liquid pool, fresh processing liquid can be always delivered. In addition, it is possible to prevent the processing solution that easily crystallizes from crystallizing in the trap tank. Furthermore, since at least a part of the flow path has transparency, it is possible to attach, for example, an optical sensor or the like to detect the presence or absence of the processing liquid in the flow path.

[Brief description of the drawings]

FIG. 1 is an overall view showing a schematic configuration of a substrate processing apparatus according to an embodiment.

FIG. 2 is a diagram illustrating an optical sensor.

FIG. 3 is a diagram showing an operation state of an optical sensor in a flow path portion.

FIG. 4 is a longitudinal sectional view showing a trap tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 4 ... Nozzle 6 ... Control part 7 ... Input part 10 ... Processing liquid tank 11 ... Liquid sending line 12 ... Trap tank 13 ... Inlet 14 ... Discharge port 15 ... Flow path part 16 ... Liquid pool part 16a ... Upper part 16b ... Lower part 17 … Sending port 18… Tank side optical sensor 20… Drain line 21… Drain side optical sensor 22… Open / close valve 30… Branch part 41… Branch tube 42… Tube 43… Top body 44… Bottom body W… Substrate

Continued on the front page (72) Inventor Naoyuki Nagata 4-chome, Horikawa-dori-Terauchi, Kamigyo-ku, Kyoto-shi, Kyoto 1-1-1 Dai Nippon Screen Manufacturing Co., Ltd. F-term (reference) 5F046 JA03 in 1 Honkawa-dori Teranouchi, Kamigyo-ku

Claims (3)

[Claims] 1. A substrate processing apparatus for performing processing on a substrate by supplying a processing liquid to a substrate from a trap tank having a liquid storage portion for temporarily storing the processing liquid sent thereto, wherein the processing in the trap tank is performed. And a remaining amount detecting means for detecting a remaining amount of the liquid, wherein the remaining amount detecting means is provided in a flow path connecting an inlet for injecting the fed processing liquid into the trap tank and the liquid reservoir. A substrate sensor for detecting the presence or absence of a processing liquid in the substrate processing apparatus. 2. The substrate processing apparatus according to claim 1, wherein the apparatus further includes an opening / closing valve that opens and closes a discharge path that is connected to the trap tank for discharging gas in the liquid reservoir. A substrate processing apparatus comprising: an optical sensor for detecting the presence or absence of a processing liquid in a discharge path from the trap tank to the on-off valve; and valve control means for closing the on-off valve when the optical sensor detects a processing liquid. 3. A trap tank provided with a liquid reservoir for temporarily storing a processing liquid sent thereto, wherein said trap tank communicates with said liquid reservoir at one end, and at least a part of a side wall is made of a material that transmits light. The formed flow path portion, comprising a branch portion that branches the other end side of the flow path portion into an injection port into which the processing liquid is injected, and a discharge port that discharges gas in the liquid pool portion, The liquid reservoir has a tapered shape in which the upper portion becomes smaller upward and communicates with the flow path portion at the upper end position, while the lower portion has a tapered shape which becomes smaller downward and is processed at the lower end position. A trap tank provided with a delivery port for delivering a liquid.