JP2001276763A - Ultrasonic treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic treatment apparatus capable of preventing a treatment liquid with a high permeability from penetration and adhesion to an ultrasonic oscillator. SOLUTION: This ultrasonic treatment apparatus comprises an apparatus body 1 which contains a nozzle body 3 in which a first flow channel 4 is formed to pass a treatment liquid to treat an object to be treated and an ultrasonic wave oscillator to give ultrasonic vibrations to the treatment liquid flowing in the flow channel of the nozzle body. In the ultrasonic treatment apparatus, the nozzle body is provided with a supply port 7 supply the treatment liquid to the first flow channel of and a flow-out outlet 6 to discharge the treatment liquid to which ultrasonic waves are supplied through and the part where the ultrasonic vibrations from the ultrasonic oscillator come into the first flow channel is so composed as to have a structure closed liquid-tightly by a permeation wall 5 integrated with the nozzle body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic processing apparatus for applying ultrasonic vibration to a processing liquid for processing an object to be cleaned.

[0002]

2. Description of the Related Art For example, in an apparatus for manufacturing a liquid crystal display device or a semiconductor device, various processes such as cleaning an object to be cleaned such as a glass substrate or a semiconductor wafer with a high degree of cleanliness, and removing a resist or an organic substance. Is required.

[0003] As a method of treating the object to be cleaned, a dip method in which a plurality of objects to be cleaned are immersed in a treatment liquid or a single-wafer method in which the treatment liquid is sprayed toward the object to be cleaned and washed one by one. In recent years, a precise processing accuracy can be obtained, and a single-wafer method which is advantageous in cost is often adopted.

[0004] As one of the single-wafer methods, ultrasonic vibration is applied to a treatment liquid sprayed on a cleaning object, and the vibration action is used to efficiently remove fine particles, resist, organic substances, and the like from the cleaning object. Processing methods have been put to practical use.

[0005] Conventionally, the vibration applied to the processing liquid is 20 to 2 times.
It was an ultrasonic wave of about 00 kHz, but recently
An ultrasonic processing device that applies a sound wave in the ultra-ultrasonic band of about 5000 kHz has been developed.

[0006] The ultrasonic processing apparatus has an apparatus main body, and a flow section through which a processing liquid is supplied is formed in the apparatus main body so as to penetrate vertically. A supply port for supplying the processing liquid communicates with an upper portion of the circulation portion, and a nozzle body is attached to a lower end portion. The nozzle body is formed with a flow path that penetrates vertically, and the processing liquid supplied from the supply port to the distribution section flows in from one end of the flow path and flows out from the other end toward the workpiece. It is supposed to.

In the apparatus main body, a diaphragm having an ultrasonic vibrator attached to a portion facing the upper end of the flow path of the nozzle body is provided so as to close the upper end opening of the flow portion in a liquid-tight manner. ing. In other words, the diaphragm has the surface on which the ultrasonic vibrator is provided facing upward, and the lower surface thereof is liquid-tightly closed through the packing formed of a resin having chemical resistance such as fluororesin. .

An ultrasonic oscillator is connected to the ultrasonic vibrator. The ultrasonic oscillator outputs power of a predetermined frequency and applies the power to the ultrasonic vibrator. As a result, the ultrasonic vibrator vibrates ultrasonically, so that the vibrating plate also vibrates ultrasonically to apply ultrasonic vibration to the processing liquid supplied to the circulation section of the apparatus main body.

[0009]

As the treatment liquid for treating the object to be treated, not only a cleaning solution such as pure water for cleaning the object to be treated as described above, but also a stripping solution for removing the resist, etc. Is used.

[0010] For example, a mixed solution of dimethyl sulfoxide and monoethanolamine is used as the stripping solution. This type of stripper has high permeability. Therefore, a part of the stripping solution supplied to the circulation part of the apparatus main body may pass through a joint portion between the diaphragm and the packing and enter the upper surface side of the diaphragm. Then, the processing liquid adheres to the ultrasonic vibrator attached to the upper surface of the vibration plate, and the electrodes provided on the ultrasonic vibrator are short-circuited.

An object of the present invention is to provide an ultrasonic processing apparatus that prevents a processing liquid from penetrating and attaching to an ultrasonic vibrator even when a processing liquid having high permeability is used. .

[0012]

According to a first aspect of the present invention, there is provided a nozzle body having a device main body, in which a first flow path through which a processing liquid for processing an object to be processed is passed is formed. In an ultrasonic processing apparatus provided with an ultrasonic vibrator for applying ultrasonic vibration to a processing liquid flowing through a flow path of a nozzle body, the nozzle body includes a supply port that supplies the processing liquid to the first flow path; An outlet is formed through which the processing liquid supplied from the supply port to the first flow path and to which the ultrasonic vibration is given is opened, and the ultrasonic vibration from the ultrasonic vibrator is transmitted to the first flow path. The ultrasonic processing apparatus is characterized in that the portion incident on the flow path is closed in a liquid-tight manner by a transmission wall integrally formed with the nozzle body.

According to a second aspect of the present invention, the nozzle body is mounted on a mounting portion formed on the apparatus main body, and the ultrasonic vibrator is provided on the apparatus main body via a diaphragm in a liquid-tight manner. 2. The ultrasonic processing apparatus according to claim 1, wherein a second flow path for passing a fluid is formed between the plate and the permeable wall.

According to a third aspect of the present invention, the angle at which the ultrasonic vibration from the ultrasonic vibrator is incident on the transmission wall of the nozzle body depends on the material of the nozzle body and the fluid flowing through the second flow path. 3. The ultrasonic treatment apparatus according to claim 2, wherein the inclination is within a range of a critical angle determined by the following.

According to a fourth aspect of the present invention, there is provided a nozzle body having a flow path through which a processing liquid for processing an object to be processed is formed, and an ultrasonic vibrator for applying ultrasonic vibration to the processing liquid flowing through the flow path of the nozzle body. In the ultrasonic processing apparatus provided, the nozzle body is
A supply port for supplying the processing liquid to the flow path and an outlet for flowing the processing liquid supplied to the flow path from the supply port are formed in the opening, and the nozzle body is vibrated on the outer surface of the nozzle body. Wherein the ultrasonic vibrator for applying ultrasonic vibration to the processing liquid flowing through the flow path is attached.

According to the first aspect of the present invention, only the supply port and the outflow port of the processing liquid are formed in the nozzle body, and the portion of the nozzle body to which the ultrasonic vibration is incident is formed by the transmission formed integrally with the nozzle body. Closed by a wall. Therefore, since the nozzle body has no joint using packing, the processing liquid supplied to the first flow path of the nozzle body does not permeate to the outside and adhere to the ultrasonic vibrator.

According to the second aspect of the present invention, since the second flow path through which the fluid for cooling the ultrasonic vibrator passes is formed in the apparatus main body, the ultrasonic vibrator can be prevented from being damaged by heat generation. .

According to the third aspect of the present invention, the angle at which the ultrasonic vibration is incident on the transmission wall of the nozzle body is inclined within a critical angle determined by the fluid flowing through the second flow path and the material of the nozzle body. This allows the ultrasonic vibration to be incident on the first flow path of the nozzle body without being reflected by the transmission wall.

According to the fourth aspect of the present invention, only the supply port and the outflow port of the processing liquid are formed in the nozzle body, and the ultrasonic vibrator is attached to the outer surface of the nozzle body to vibrate the nozzle body. Thus, the treatment liquid was vibrated. Therefore, since the nozzle body does not have a joint using packing, the processing liquid does not permeate from the flow path of the nozzle body and adhere to the ultrasonic vibrator.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention.
This shows a point type ultrasonic cleaning device.
It has an apparatus main body 1 made of metal such as stainless steel. This equipment
A mounting part 2 having one end opened at a lower end surface is mounted on a main body 1.
Line O₁To the axis O of the device body ₂Predetermined angle to
It is formed. This inclination angle is indicated by θ in the figure.
You.

A nozzle body 3 is mounted on the mounting portion 2 by packing.
It is screwed liquid-tight through the ring 3a. By that
The nozzle body 3 has an axis whose angle is the same as the inclination angle of the mounting portion 2.
It is provided at an angle θ. Axis of nozzle body 3
Is the same O as the axis of the mounting portion 2₁ It is.

A first flow path 4 is formed in the nozzle body 3. The upper end of the first flow path 4 is closed by a permeable wall 5, and the lower end is an outlet 6 opened on the lower end surface of the nozzle body 3. Further, an upper portion of the first flow path 4 communicates with a supply port 7 formed in the upper side surface of the nozzle body 3.

The transmission wall 5 is thinner than the other parts of the nozzle body 3 and is formed integrally with the nozzle body 3. That is, the nozzle body 3 is formed by grinding the metal block, for example, so that the first wall is left while leaving the transmission wall 5.
, An outlet 6 and a supply port 7 are formed. As a result, the nozzle body 3 has a liquid-tight structure except for the outlet 6 and the supply port 7.

In the apparatus main body 1, a second flow path 11 having a lower end communicating with the mounting portion 2 is formed. In the second flow path 11, a supply port 12 and an outflow port 13 formed on one side surface and the other side surface of the apparatus main body 1 communicate with each other.

Further, the apparatus main body 1 has a recess 15 whose lower end communicates with the second flow path 11 and whose upper end is open to the upper end surface of the apparatus main body 1. The recess 15 is formed to have a larger diameter than the second flow path 11. Thereby,
A step 16 is provided at the boundary between the second flow path 11 and the recess 15.
Are formed.

A diaphragm 17 made of sapphire, stainless steel, or the like is provided on the step 16 in a state where the upper end of the second flow path 11 is closed.
0 and are provided in a liquid-tight manner. An ultrasonic vibrator 18 is attached to the upper surface of the vibrating plate 17.
Incidentally, the plate surface of the vibrating plate 17 is perpendicular to the axis O ₂ of the apparatus main body 1.

As shown in FIG. 2, the ultrasonic transducer 18 is provided with a first electrode 18a and a second electrode 18b. The first electrode 18a is connected to the ultrasonic vibrator 1
7 is provided at the center of the upper surface of the second electrode 18b.
Is provided over the entire lower surface of the ultrasonic vibrator 17 joined to the vibration plate 17 and the peripheral portion of the upper surface. Therefore, the ultrasonic vibrator 17 is connected to the first and second electrodes 1.
As described later, power of a predetermined frequency is supplied to the first electrode 18a and the second electrode 18b.
The ultrasonic wave vibrates in a portion facing the.

A coil spring 23 serving as a first contactor is provided on the upper surface of the vibration plate 17 having the lower surface peripheral portion engaged with the step portion 16, that is, on the first electrode 18a on the upper surface of the ultrasonic vibrator 18. Are provided with their lower ends in contact with each other.
A ring-shaped pressing member 24 as a second contact is in contact with the electrode 18b. The coil spring 23 is housed in a collar 25 made of an insulating material. The pressing member 2
4 is in electrical contact with the second electrode 18b.

A ring-shaped electrode 26 made of a conductive material is provided in the recess 15 of the apparatus main body 1.
The ring-shaped electrode 26 is provided with its lower end surface in electrical contact with the pressing member 24.

Further, a pressing member 27 made of fluororesin is screwed into the recess 15 from above the ring-shaped electrode 26. An insulating member 28 housed in the collar 25 is provided on a lower surface of the pressing member 27. Between the insulating member 28 and the coil spring 23, there is provided an electrode member 29 which enters the collar 25 to press the coil spring 23 and is in electrical contact with the coil spring 23.

The vibrating plate 17 is controlled by the pressing member 27.
Are pressed with a predetermined pressing force. Thereby, the diaphragm 17 closes the open portion at the upper end of the second flow path 11 in a liquid-tight manner by the O-ring 17.

An insertion hole 32 is provided at the center of the pressing member 27.
The end of the coaxial cable 31 is inserted and fixed therein. A core wire 31a at one end of the coaxial cable 31 is connected to the electrode member 29, and a covered wire 31b is connected to the ring electrode 26. The other end of the coaxial cable 31 is connected to an ultrasonic oscillator 33.

Therefore, a voltage is applied to the first electrode 18a and the second electrode 18b of the ultrasonic vibrator 18 by the ultrasonic oscillator 33, and the ultrasonic vibrator 18 can be ultrasonically vibrated. It has become.

An O-ring 36 for preventing liquid from flowing into the concave portion 15 is provided at the upper end opening of the concave portion 15 of the apparatus main body 1, and a pressing member 27 is provided on the upper end surface thereof. A press plate 34 for preventing the slide plate 15 from falling out is fixed by screws 35.

In the ultrasonic vibration device having the above structure, pure water as a cooling fluid is supplied from the supply port 12 of the main body 1 to the second flow path 11, and the first water is supplied from the supply port 7 of the nozzle body 3. A processing liquid such as a stripping liquid or an etching liquid is supplied to the flow path 4. At the same time, the ultrasonic oscillator 33 is operated to supply power to the ultrasonic vibrator 18, so that the ultrasonic vibrator 18 and the diaphragm 17 are ultrasonically vibrated.

The ultrasonic vibration generated by the vibration plate 17
The pure water flowing through the flow path 11 propagates through the transmission wall 5 of the nozzle body 3 and enters the first flow path 4 of the nozzle body 3. Thus, the processing liquid flowing through the first flow path 4 of the nozzle body 3 is subjected to ultrasonic vibration.

The nozzle body 3 has no opening except for the supply port 7 and the outflow port 6. That is, as in the conventional case, in order to make the ultrasonic vibration enter the first flow path 4 of the nozzle body 3, the upper end face of the first flow path 4 facing the ultrasonic vibrator 18 is opened. In this case, the diaphragm 17 is not liquid-tightly joined via a packing.

That is, the nozzle body 3 is provided with a thin transmission wall 5 integrally formed with the nozzle body 3, and ultrasonic vibration is made incident on the first flow path 4 in the nozzle body 3 from the transmission wall 5. I did it.

Therefore, even if the processing liquid supplied to the first flow path 4 is a liquid having a high permeability, such as a stripping liquid, the nozzle body 3 does not have a joint using packing, so that the processing liquid Is penetrated to the outside from the joining portion and adheres to the ultrasonic vibrator 18 like a conventional ultrasonic processing apparatus, and the first electrode 18a and the second electrode 18 provided on the ultrasonic vibrator 18 are provided.
b is not electrically short-circuited.

When the ultrasonic vibrator 18 is driven, heat is generated, and the heat may damage the ultrasonic vibrator 18 or deform the diaphragm 17. However, pure water flows through the second flow path 11 between the nozzle body 3 and the diaphragm 17. Therefore, the vibration plate 17 and the ultrasonic vibrator 18 are cooled by pure water flowing through the second flow path 11, so that the vibration plate 17 and the ultrasonic vibrator 18 may be damaged,
Deformation can be prevented.

The second flow path 11 is provided with a step 15 of the apparatus main body 1.
Is closed by a vibrating plate 17 provided in a liquid-tight manner by an O-ring 17. That is, a joining structure using the O-ring 17 is employed. However, the fluid flowing through the second flow path 11 is pure water, for example, and is not a highly permeable treatment liquid such as a stripping liquid. There is no such thing as to adhere to the ultrasonic vibrator 18 provided on the upper surface.

Similarly, the fluid flowing through the second flow path 11 does not permeate at the joint between the nozzle body 3 and the apparatus main body 1 by the O-ring 3a.

[0044] The nozzle body 3 is inclined at a predetermined angle θ to the axis O ₁ relative to the axis O ₂ of the apparatus main body 1. That is, the plate surface of the transmission wall 5 of the nozzle body 3 is inclined at an angle θ with respect to the axis O ₂ of the apparatus main body 1. This angle θ is inclined within the range of the critical angle of total reflection determined by the pure water flowing through the second flow path 11 through which the ultrasonic vibration from the diaphragm 18 propagates and the material of the transmission wall 5 of the nozzle body 3. ing.
The critical angle can be obtained by the following equation.

That is, generally, the law of refraction is that the incident angle is θ
₁ , assuming that the refraction angle is θ ₂ , sin θ ₁ / sin θ ₂ = V ₁ / V ₂ = λ ₁ / λ ₂ = n (1) Where V ₁ , λ ₁ and V
_2, the lambda ₂ medium before incidence, a propagation speed and wavelength according to the medium after the incident, n represents a constant.

The incident angle θ ₁ when the refraction angle θ ₂ reaches 90 degrees is the critical angle for total reflection.

Since the above equation (1) is sin θ ₁ / sin θ ₂ = V ₁ / V ₂ (2), if θ ₂ = 90 degrees, sin θ ₂ =
1, and the incident angle θ ₁ is given by sin θ ₁ = V ₁ / V ₂ (3) Propagation velocity _{V 1} of the pure water is 1480 m / sec, since the propagation velocity _{V 2} of the stainless steel is 5000 m / sec, from equation (3), the critical angle theta ₁ of the total reflection 17.2
It becomes degree.

Therefore, the inclination angle θ of the axis O ₁ of the nozzle body 3 with respect to the axis O ₂ of the apparatus main body 1 is determined by the critical angle θ
_In the range of _1, the ultrasonic vibration from the vibration plate 17 does not undergo total reflection at the boundary surface between the pure water and the transmission wall 5 but passes through the transmission wall 5 and the first flow of the nozzle body 3 flows. Since the light enters the passage 4, the processing liquid flowing through the first passage 4 can be reliably subjected to ultrasonic vibration.

Moreover, since the plate surface of the transmitting wall 5 is inclined with respect to the axis O ₂ of the apparatus main body 1, that is, the traveling direction of the ultrasonic vibration, the ultrasonic vibration from the diaphragm 17 is transmitted by the transmitting wall 5.
There is no specular reflection and return, and the diaphragm 17 and the ultrasonic vibrator 18 are not damaged.

[0050] In the first embodiment is inclined 5 degrees nozzle body 3 with respect to the axis O ₂ of the apparatus main body 1, but since it is sufficient to tilt within the critical angle, the angle of inclination θ That is, the angle may be set within a range of approximately 1 to 17 degrees.

FIG. 3 shows an ultrasonic processing apparatus according to a second embodiment of the present invention. In the nozzle body 51 of the ultrasonic processing apparatus according to this embodiment, a flow path 53 is formed in a corrosion-resistant metal block such as stainless steel. This channel 53
Is a supply port 54 formed on one side of the metal block.
Outlet 55 which communicates with the
Is in communication with

A processing liquid such as a stripping liquid is supplied to the channel 53 from the supply port 54. This processing liquid flows out from the outlet 55.

An ultrasonic vibrator 18 having the same structure as that shown in FIG. 2 is bonded and fixed to the upper surface of the nozzle body 51 by means such as adhesion. The ultrasonic vibrator 18 is electrically connected to an ultrasonic oscillator 33 by a coaxial cable 31. Therefore, when power of a predetermined frequency is supplied from the ultrasonic oscillator 33 to the ultrasonic vibrator 18, the ultrasonic vibrator 18 ultrasonically vibrates.
The nozzle body 51 can be tuned to this ultrasonic vibration. If the nozzle body 51 vibrates ultrasonically, this nozzle body 5
Ultrasonic vibration is applied to the processing liquid flowing through the flow path 53 formed in the first step.

A cylindrical body 56 is integrally provided on the upper surface of the nozzle body 51, and a holder 56 for holding the coaxial cable 31 is attached to the cylindrical body 56. At least one of the holder 56 and the nozzle body 51 is attached to a fixed portion (not shown) via an elastic member (not shown) so as to be elastically displaceable. Therefore, the nozzle body 51 is ultrasonically vibrated by the ultrasonic vibrator 18 while elastically deforming the elastic member.

According to the ultrasonic processing apparatus having the above-described structure, the nozzle body 51 has only the supply port 54 and the outlet port 55 formed therein, and does not have a joint using packing as in the conventional case. Therefore, even if the processing liquid supplied to the channel 53 is a highly permeable chemical such as a stripping liquid, the nozzle 51
Of the ultrasonic vibrator 18 attached to the outer surface of the nozzle 51
The processing liquid does not adhere to the electrodes, and the electrodes are not electrically short-circuited.

[0056]

According to the first aspect of the present invention, only the supply port and the outflow port of the processing liquid are formed in the nozzle body, and the portion where the ultrasonic vibration enters the nozzle body is integrally formed with the nozzle body. Is closed by a transparent wall.

Therefore, the nozzle body does not have a portion for maintaining a liquid-tight state by using packing as in the conventional case.
Even if the permeability of the processing liquid flowing through the nozzle body is high, the processing liquid does not permeate from the joint portion and adhere to the ultrasonic vibrator.

According to the second aspect of the present invention, the second flow passage through which the fluid flows along the vibrating plate is formed in the apparatus main body.

For this reason, the ultrasonic vibrator is cooled by the fluid flowing through the second flow path via the vibration plate, and the air bubbles adhering to the vibration plate are removed to prevent the diaphragm from being idled. The sonic vibrator can be prevented from being damaged by heat.

According to the third aspect of the present invention, the angle at which the ultrasonic vibration is incident on the transmission wall of the nozzle body is inclined within a critical angle determined by the fluid flowing through the second flow path and the material of the nozzle body. I tried to make it.

For this reason, at the boundary between the fluid flowing through the second flow path and the permeable wall, the ultrasonic vibration can be made incident on the first flow path of the nozzle body without being reflected.
Ultrasonic vibration can be reliably applied to the processing liquid flowing through the flow path.

According to the fourth aspect of the present invention, only the supply port and the outflow port of the processing liquid are formed in the nozzle body, and the ultrasonic vibrator is attached to the outer surface of the nozzle body to vibrate the nozzle body. Thus, the processing liquid flowing through the flow path of the nozzle body is vibrated.

For this reason, the nozzle body does not need to be provided with a joining portion using packing as in the prior art. Even if the processing liquid flowing through the nozzle body has a high permeability, the processing liquid permeates from the joining portion. Thus, it can be prevented from adhering to the ultrasonic vibrator.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an ultrasonic processing apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing the ultrasonic vibrator attached to the diaphragm.

FIG. 3 is a longitudinal sectional view of an ultrasonic processing apparatus showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Device main body 3 ... Nozzle body 4 ... First flow path 5 ... Permeation wall 6, 55 ... Outlet 7, 54 ... Supply port 11 ... Second flow path 18 ... Ultrasonic vibrator 51 ... Nozzle body

Claims (4)

[Claims] A nozzle body having a first flow path through which a processing liquid for processing an object to be processed is formed, and a processing liquid flowing through the flow path of the nozzle body. In an ultrasonic processing apparatus provided with an ultrasonic vibrator that imparts ultrasonic vibration, the nozzle body is configured to supply the processing liquid to the first flow path and to supply the processing liquid from the supply port to the first flow path. An outlet for supplying the processing liquid to which the supplied ultrasonic vibration is applied is formed with an opening, and a portion where the ultrasonic vibration from the ultrasonic vibrator is incident on the first flow path is the nozzle body. An ultrasonic treatment apparatus having a structure closed in a liquid-tight manner by a transmission wall integrally formed with the ultrasonic treatment apparatus. 2. The apparatus according to claim 1, wherein the nozzle body is mounted on a mounting portion formed on the apparatus main body, and the ultrasonic vibrator is provided on the apparatus main body via a diaphragm in a liquid-tight manner. 2. The ultrasonic processing apparatus according to claim 1, wherein a second flow path through which the fluid flows is formed between the ultrasonic processing apparatus and the second processing apparatus. 3. An angle at which ultrasonic vibration from the ultrasonic vibrator is incident on the transmission wall of the nozzle body is a critical angle determined by a material of the nozzle body and a fluid flowing through the second flow path. 3. The ultrasonic processing apparatus according to claim 2, wherein the ultrasonic processing apparatus is inclined within a range. 4. An ultrasonic processing apparatus comprising: a nozzle body having a flow path through which a processing liquid for processing an object is passed; and an ultrasonic vibrator for applying ultrasonic vibration to the processing liquid flowing through the flow path of the nozzle body. In the apparatus, the nozzle body has an opening formed with a supply port for supplying the processing liquid to the flow path and an outlet for flowing the processing liquid supplied to the flow path from the supply port, and an outer surface of the nozzle body. Wherein the ultrasonic vibrator for vibrating the nozzle body to apply ultrasonic vibration to the treatment liquid flowing through the flow path is attached.