US20180087170A1

US20180087170A1 - Wet Surface Treatment Apparatus

Info

Publication number: US20180087170A1
Application number: US15/571,996
Authority: US
Inventors: Toshinori Kawamura; Hiroshi Nakano
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2015-05-08
Filing date: 2016-03-11
Publication date: 2018-03-29
Also published as: CN107532323B; WO2016181698A1; CN107532323A; JPWO2016181698A1; JP6496015B2

Abstract

There is provided a wet surface treatment apparatus which can perform surface treatment on a desired place of a surface treatment target member, irrespective of an installed place of the surface treatment target member, or a shape of the surface treatment target member. A wet surface treatment apparatus according to the present invention has a tank that contains a treatment liquid, a nozzle that ejects the treatment liquid to a surface treatment target member, and a power source that supplies a current to the nozzle. The nozzle has a nozzle body, which has a flow path of the treatment liquid, a nozzle cover in which one end is connected to a tip of the nozzle body and the other end comes into contact with the surface treatment target member, and a power feeder line which supplies the current from the power source to the nozzle body and the nozzle cover.

Description

TECHNICAL FIELD

The present invention relates to a wet surface treatment apparatus.

BACKGROUND ART

General wet surface treatment represented by plating is performed as follows. A plurality of treatment tanks including a water washing tank, or anterior and posterior surface treatment tanks are arrayed in order of processes, and a surface treatment target member moves to the respective treatment tanks in sequence. Therefore, a wet surface treatment apparatus is lengthened in size long as a whole. In addition, due to immersion treatment, the treatment tank needs to be larger than the surface treatment target member. Consequently, a size of the wet surface treatment apparatus increases. Furthermore, when the surface treatment is partially performed, it is necessary to form a resist on a surface treatment target portion.
For example, as a wafer plating apparatus in the related art, PTL 1 (JP-A-6-57497) discloses the following plating apparatus. The plating apparatus includes a cup into which a plating solution is injected, multiple plating solution outflow hole radially disposed on an upper wall portion of the cup, a ring-shaped rubber sheet disposed on an upper surface of the cup, and a cathode electrode disposed on an upper surface of the rubber sheet in a state where an end portion is located outward as far as a predetermined distance from an inner peripheral end of the rubber sheet. In a state where a plating connection terminal disposed on a plating target surface of a wafer is brought into contact with the cathode electrode, a substantial periphery of the plating target surface is brought into close contact with the upper surface of the rubber sheet.
In addition, as an apparatus for decreasing a size of the wet surface treatment apparatus, PTL 2 (JP-A-2012-67362) proposes the following plating apparatus, for example. In order to continuously performing plating with a single treatment tank, the plating apparatus includes one treatment tank and a switching valve for causing only one or more pipes selected from a plurality of pipes to communicate with the treatment tank. In addition, as a method of partially performing the wet surface treatment, PTL 3 (JP-A-59-96289) proposes the following plating apparatus, for example. In order to partially performing the plating by ejecting a plating solution from a nozzle connected to a mask, the plating apparatus includes a mantle box having an exclusion port connected to the mask and an aspiration mechanism for bringing the inside of the nozzle and the mantle box into a negative pressure state.

CITATION LIST

Patent Literature

PTL 1: JP-A-6-57497
PTL 2: JP-A-2012-67362
PTL 3: JP-A-59-96289

Summary of Invention

Technical Problem

In a case where a large structure member or a structure member fixed onto the land is a surface treatment target, a surface treatment apparatus needs to be portable, and does not need to choose a shape of a surface treatment target member. However, the apparatuses disclosed in PTLS 1 to 3 are less likely to satisfy this requirement. That is, according to techniques disclosed in PTLS 1 to 3, the surface treatment apparatuses themselves are not movably used. The apparatuses are so-called in-line apparatuses. In addition, the apparatuses have an apparatus configuration adapted to the surface treatment target member having a shape and a size which are determined to a certain extent, and thus, the apparatuses cannot perform surface treatment on any desired portion of the large structure member or the structure member fixed onto the land.
PTL 2 attempts to decrease the size of the wet surface treatment apparatus by using a switching valve so as to employ one treatment tank. However, the surface treatment target member has to be installed inside the treatment tank. Consequently, the treatment tank needs to be larger in size than the surface treatment target member, and thus, the large structure member or the structure member fixed onto the land cannot be a plating treatment target.
In PTLS 1 and 3, a wafer or an IC chip is the plating treatment target. PTL 1 does not enable partial plating treatment. In addition, PTL 3 enables partial plating treatment by ejecting the plating solution from the nozzle connected to the mask. However, PTL 3 adopts an apparatus configuration on the assumption that a flat substrate is set as the surface treatment target member. Therefore, in order to obtain adhesion between the surface treatment target member and the mask, a surface of the surface treatment target member has to be flat, and it is necessary to press the mask or the surface treatment target member. Consequently, the wet surface treatment is less likely to be performed on an irregular surface, a curved surface, and a large surface area.
In view of the above-described circumstances, the present invention aims to provide a wet surface treatment apparatus which can perform surface treatment on a desired place of a surface treatment target member, irrespective of an installed place of the surface treatment target member, or a shape and a size of the surface treatment target member.

Solution to Problem

According to the present invention, in order to achieve the above-described object, there is provided a wet surface treatment apparatus including a tank that contains a treatment liquid, a nozzle that ejects the treatment liquid to a surface treatment target member, and a power source that supplies a current to the nozzle. The nozzle has a nozzle body which has a flow path of the treatment liquid, a nozzle cover in which one end is connected to a tip of the nozzle body and the other end comes into contact with the surface treatment target member, and a power feeder line which supplies the current from the power source to the nozzle body and the nozzle cover.

Advantageous Effects of Invention

According to the present invention, it is possible to provide a wet surface treatment apparatus which can perform surface treatment on a desired place of a surface treatment target member, irrespective of an installed place of the surface treatment target member, or a shape and a size of the surface treatment target member.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram illustrating a first embodiment of a wet surface treatment apparatus according to the present invention.

FIG. 2A is a top view of a nozzle cover illustrated in FIG. 1.

FIG. 2B is a bottom view of the nozzle cover illustrated in FIG. 1.

FIG. 3A is a sectional view taken along line A-A′ in FIG. 2A.

FIG. 3B is a sectional view taken along line B-B′ in FIG. 2A.

FIG. 1 is a schematic diagram illustrating a second embodiment of a wet surface treatment apparatus according to the present invention.

FIG. 5A is a top view of a nozzle cover illustrated in FIG. 4.

FIG. 5B is a bottom view of the nozzle cover illustrated in FIG. 4.

FIG. 6A is a sectional view taken along line A-A′ in FIG. 5A.

FIG. 6B is a sectional view taken along line B-B′ in FIG. 5A.

FIG. 7A is a top view schematically illustrating a nozzle cover of a third embodiment of a wet surface treatment apparatus according to the present invention.

FIG. 7B is a bottom view schematically illustrating the nozzle cover of the third embodiment of the wet surface treatment apparatus according to the present invention.

FIG. 8A is a sectional view taken along line A-A′ in FIG. 7A.

FIG. 8B is a sectional view taken along line B-B′ in FIG. 7A.

FIG. 9 is a sectional view schematically illustrating another embodiment of a nozzle cover of a wet surface treatment apparatus according to the present invention.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
However, the present invention is not limited to these embodiments. Improvements and modifications can be appropriately added to the present invention within the scope in which the gist of the invention is not changed.

First Embodiment

FIG. 1 is a schematic diagram illustrating a first embodiment of a wet surface treatment apparatus according to the present invention. First of all, an overall configuration of the wet surface treatment apparatus according to the present invention will be described with reference to FIG. 1. As illustrated in FIG. 1, a wet surface treatment apparatus 100 a according to the present invention has a tank 11 that contains a treatment liquid, a nozzle 4 that ejects the treatment liquid onto a surface of a surface treatment target member 7, and a power source (DC power source) 8 that supplies a current to the nozzle 4. In the wet surface treatment apparatus according to the present invention, the nozzle 4 has a portable size and shape. Even if the surface treatment target member 7 is a large structure member or a structure member fixed onto the land, the wet surface treatment apparatus has a configuration in which surface treatment can be partially performed on the structure member. Hereinafter, a specific configuration will be described.
The nozzle 4 has a nozzle body 4 a and a nozzle cover 4 b. The nozzle body 4 a internally has a flow path of the treatment liquid. It is preferable that the nozzle cover 4 b is flexible. In this manner, the nozzle cover 4 b is installed so as to be in close contact with the surface treatment target member 7, and thus, the treatment liquid can be prevented from leaking. A configuration of the nozzle body 4 a and the nozzle cover 4 b will be described in detail later. A shape and a size of the nozzle 4 are not particularly limited. However, it is preferable that the shape and the size allow easy manual operation. If necessary, it is preferable to provide a function to switch the treatment liquid to the nozzle 4, a function to switch a polarity of the current, a function to adjust the amount of the current, and a function to adjust an ejection amount, thereby improving workability.
The power source 8 supplies the current to the treatment liquid and the surface treatment target member 7 via the nozzle 4. Although not illustrated in FIG. 1, the nozzle body 4 a and the nozzle cover 4 b internally have a power feeder line so as to adopt a configuration in which the current can be supplied thereto via the power feeder line.
The treatment liquid (surface treatment liquid used for the surface treatment of the surface treatment target member 7) contained in the tank 11 is supplied to the nozzle 4 via a treatment liquid circulation tube (hereinafter, simply referred to as a “tube”) 9 and a circulation pump 10. In addition, in the treatment liquid ejected from the nozzle 4, the treatment liquid (waste liquid) which is not applied to the surface treatment target member 7 is contained again in the tank 11 via an outflow hole disposed in the nozzle cover 4 b (to be described later), a tube 9′, and a circulation pump 10′. In this manner, the waste liquid is reused.
If necessary, the tank 11 may contain a plurality of different treatment liquids by being internally divided into a plurality of rooms. In this case, a desired treatment liquid can be selected by a switching valve 12, and can be fed to the nozzle 4. In addition, the collected treatment liquid can be collected into the desired room by a switching valve 12′. Each switching port of the switching valves 12 and 12′ is disposed depending on the number of rooms.
Next, the nozzle body 4 a and the nozzle cover 4 b which configure the nozzle 4 will be described. FIG. 2A is a top view of the nozzle cover 4 b in FIG. 1, and FIG. 2B is a bottom view of the nozzle cover 4 b in FIG. 1. The top view of the nozzle cover 4 b is a view when viewed in a direction toward the nozzle cover 4 b from the nozzle body 4 a, and the bottom view of the nozzle cover 4 b is a view when viewed in a direction toward the nozzle body 4 a from a surface on which the nozzle cover 4 b comes into contact with the surface treatment target member 7. FIG. 3A is a sectional view taken along line A-A′ in FIG. 2A, and FIG. 3B is a sectional view taken along line B-B′ in FIG. 2A. As illustrated in FIGS. 2A, 3A, and 3B, inside the nozzle cover 4 b, a power feeder line 2 for supplying the current to the surface treatment target member 7 is disposed from a nozzle body tip portion 4 c (portion to which the nozzle cover 4 b is connected) toward the surface treatment target member 7. That is, the power feeder line 2 is disposed from the power source 8 via the nozzle body 4 a to the tip of the nozzle cover 4 b so as to supply the current to the nozzle cover 4 b. The number of power feeder lines 2 is not particularly limited. However, it is desirable to provide two or more power feeder lines 2 in order to improve power feeding capacity for the surface treatment target member 7.
As illustrated in FIG. 2B, the tip portion of the power feeder line 2 is exposed on a surface (contact surface) 4 d where the nozzle cover 4 b comes into contact with the surface treatment target member 7. The power feeder line 2 is disposed inside the nozzle cover 4 b, thereby shortening a power feeding distance to the surface treatment target member 7. Even if the power is fed to the surface treatment target member 7 having high electrical resistivity, it is possible to improve the power feeding capacity, and the surface treatment can be performed. In addition, a plurality of exposed surfaces of the power feeder line 2 are disposed along the circumferential direction of the contact surface 4 d, thereby enabling the power is supplied so as to surround the surface treatment target member 7. Accordingly, it is possible to improve uniformity in distributing the current density. As a result, a coating film having a desired film thickness and a uniform film thickness can be obtained. From a viewpoint of uniform current density distribution, it is preferable that the exposed surface of the power feeder line 2 is disposed symmetrically up and down and right and left on the contact surface 4 d.
As illustrated in FIGS. 2A, 2B, and 3B, the nozzle cover 4 b has an outflow hole 3 for discharging the excess treatment liquid (waste liquid) which is not used for applying the surface treatment target member 7. The outflow hole 3 is connected to the above-described tube 9′. The treatment liquid which is not used is collected in the tank 11, and is reused.
As illustrated in FIG. 3A, the insoluble electrode 5 serving as a flow path of a treatment liquid 6 is disposed inside the nozzle body 4 a. The insoluble electrode 5 is disposed along the flowing direction of the treatment liquid 6. While the power is fed to the treatment liquid 6 supplied from the tube 9, the treatment liquid 6 is supplied to the nozzle body tip portion 4 c. The insoluble electrode 5 is disposed on the entire inner surface (that is, the entire surface of the flow path of the treatment liquid 6) of the nozzle body 4 a. In this manner, it is possible to improve power feeding capacity for the treatment liquid 6. In addition, the insoluble electrode 5 is disposed up to the nozzle body tip portion 4 c, thereby the distance to the surface treatment target member 7 to be shortened. Accordingly, the electrical resistance between both poles of the insoluble electrode 5 and the surface treatment target member 7 can be reduced. Furthermore, an electrode member is configured to include the insoluble electrode 5. Accordingly, the polarity of the current applied to the treatment liquid 6 can be changed. The surface treatment using both plating and etching can be performed on the surface treatment target member 7.
As a material of the nozzle cover 4 b, a material having electrical insulating properties and chemical resistance is used, and a flexible material (elastic material) is used so that the nozzle cover 4 b can come into close contact with the treatment target member 7 having various shapes (so as to ensure followability to a non-planar surface). For example, as the flexible material, a silicone resin or a fluorine resin is preferably used.
FIG. 9 is a sectional view schematically illustrating another embodiment of a nozzle cover of a wet surface treatment apparatus according to the present invention. The shape of the nozzle cover 4 b is not particularly limited. However, in addition to a hemispherical shape illustrated in FIGS. 3A and 3B, a multi-stage bellows shape as illustrated in FIG. 9 may be used. The flexibility of the nozzle cover 4 b can be provided using a material or a shape of the nozzle cover 4 b. In a case where the nozzle cover 4 b has the above-described material and shape, regardless that the treatment surface of the surface treatment target member 7 has any shape, the nozzle cover 4 b and the surface treatment target member 7 can be brought into close contact with each other, thereby reliably enabling the power feeding to the surface treatment target member 7 and the alignment in the ejecting direction of the treatment liquid. As means for fixing the nozzle cover 4 b to the surface treatment target member 7 is not particularly limited. However, it is possible to use an adhesive tape having chemical resistance.
A material of the power feeder line 2 is not particularly limited. However, it is preferable to use metal or a metal alloy having low electrical resistivity. More specifically, Cu (copper) or Au (gold) is preferably used.
A material of the insoluble electrode 5 is not particularly limited. However, it is preferable to use a material which has low electrical resistance and which is stable chemically and electrochemically. Specifically, a layered electrode of Ti (titanium)/Pt (platinum) and Ti (titanium)/Ir (iridium), or C (graphite) is preferably used.
A material of a housing (portion covering the flow path of the treatment liquid) of the nozzle body 4 a is not particularly limited. However, it is preferable to use a material having rigidity, chemical resistance, and electrical insulating properties. Specifically, polypropylene, polycarbonate, or fluorine resin is preferably used.
A material of the tubes 9 and 9′ is not particularly limited. However, it is preferable that the material has chemical resistance and is flexible. In addition, it is preferable that the tubes 9 and 9′ between the treatment liquid tank 11 and the switching valves 12 and 12′ are disposed depending on the number of rooms inside the treatment liquid tank 11.
The number of circulation pumps 10 and 10′ is not particularly limited. However, it is preferable to provide two or more circulation pumps in order to improve the circulating performance of the treatment liquid 6. For example, it is preferable to dispose the circulation pumps at two locations between the treatment liquid tank 11 and the nozzle 4, and between the outflow hole 3 of the nozzle cover 4 b and the treatment liquid tank 11.
The treatment liquid tank 11 is not particularly limited. However, it is desirable that the treatment liquid tank 11 contains a cleaner used in a series of the surface treatment steps or the treatment liquid 6 including etching and washing solutions. A plurality of different treatment liquids are provided, thereby enabling one apparatus to continuously perform a series of the surface treatment steps on the surface treatment target member 7. In addition, a multilayered film can be formed. In addition, it is desirable that the volume of the treatment liquid tank 11 is set in accordance with a treatment area of the surface treatment target member 7.
The characteristics of the configuration of the wet surface treatment apparatus according to the first embodiment described above are as follows. (1) The treatment liquid 6 is ejected from the nozzle 4, thereby enabling partial wet surface treatment. (2) Even in a case where the surface treatment target member 7 has a non-planar shape, the flexible nozzle cover 4 b and the power feeder line 2 exposed on the contact surface 4 d of the nozzle cover 4 b can ensure power feeding capacity. (3) The liquid supply pipe is unified by the switching valves 12 and 12′, thereby reducing the number of configuration components of the wet surface treatment apparatus. The respective configuration components are connected to each other using the flexible tubes 9 and 9′, thereby enabling the transportability of the wet surface treatment apparatus to be improved.
According to the above-described configurations of the wet surface treatment apparatus of the present invention, for example, even if the surface treatment target member 7 is a large structure member such as abridge girder and a power plant and is fixed onto the ground, the surface treatment can be performed on a desired site. Therefore, surface repair work can be easily carried out without disassembling the large structure member.

Second Embodiment

FIG. 4 is a schematic diagram illustrating a second embodiment of a wet surface treatment apparatus according to the present invention. In addition, FIG. 5A is a top view of a nozzle cover in FIG. 4, and FIG. 5B is a bottom view of the nozzle cover in FIG. 4. In addition, FIG. 6A is a sectional view taken along line A-A′ in FIG. 5A, and FIG. 6B is a sectional view taken along line B-B′ in FIG. 5A. A different point from that according to the first embodiment of the present embodiment is as follows. A vacuum pump 16 is disposed, and a plurality of decompressing holes 14 are disposed on a contact surface 4 d′ of a nozzle cover 4 b′. A connection portion 15 between the decompressing hole 14 and the vacuum pump 16 is disposed in a portion of the nozzle cover 4 b′. According to this configuration, the decompressing hole 14 is decompressed and evacuated by the vacuum pump 16, thereby improving the adhesion between the nozzle cover 4 b′ and the surface treatment target member 7. Therefore, the wet surface treatment apparatus can correspond to the surface target member 7 having various surface shapes.
As illustrated in FIG. 5A, the respective decompressing holes 14 are connected to each other in a circumferential direction of the nozzle cover 4 b′, and are connected to the vacuum pump 16 from a portion of the nozzle cover 4 b′. The number of decompressing holes 14 disposed on the contact surface 4 d′ is not particularly limited. However, it is preferable to dispose three or more decompressing holes in order to improve the adhesion.
As illustrated in FIG. 5B, the power feeder line 2 and the decompressing hole 14 are alternately arranged on a lower surface side of the nozzle cover 4 b. Since the power feeder line 2 and the decompressing hole 14 are alternately arranged, it is possible to secure both the power feeding capacity and the adhesion, even in a case where the surface treatment target member 7 has a non-planar shape.

Third Embodiment

FIG. 7A is a top view schematically illustrating a nozzle cover of a third embodiment of a wet surface treatment apparatus according to the present invention, and FIG. 7B is a bottom view schematically illustrating the nozzle cover of the third embodiment of the wet surface treatment apparatus according to the present invention. In addition, FIG. 8A is a sectional view taken along line A-A′ in FIG. 7A, and FIG. 8B is a sectional view taken along line B-B′ in FIG. 7A. A different point from that according to the first embodiment is as follows. The plurality of decompressing holes 14 are disposed in a contact surface 4 d″ of a nozzle cover 4 b″. The tip portion 4 c of the nozzle body 4 a has an aspirator 20. The decompressing hole 14 and the aspirator 20 are connected to each other inside the nozzle cover 4 b″. According to this configuration, without disposing the vacuum pump, the aspirator 20 using a flow (flow velocity) of the treatment liquid 6 flowing inside the nozzle body 4 b is employed. In this manner, the decompressing hole 14 is decompressed by the aspirator 20, thereby enabling the nozzle cover 4 b to be adsorbed to the surface treatment target portion 7.
As described above, the wet surface treatment apparatus according to the present invention is used. In this manner, irrespective of an installed place of the surface treatment target member, or a shape and a size of the surface treatment target member, the surface treatment can be performed on a desired place of the surface treatment target member. According to the above-described configuration, the transportation of the wet surface treatment apparatus is facilitated. For example, partial repair work using the wet surface treatment can be carried out for a non-planar member which is less likely to be transported, such as large infrastructure equipment installed out of doors.
The present invention is not limited to the above-described embodiments, and includes various modification embodiments. For example, the embodiments have been described above in detail in order to facilitate the understanding of the present invention, and the present invention does not necessarily include all of the described configurations. In addition, the configuration according to one embodiment can be partially substituted with the configuration of the other embodiment. In addition, the configuration of one embodiment can be added to the configuration of the other embodiment. In addition, additions, deletions, and substitutions of other configurations can be made for a partial configuration of the respective embodiments.

REFERENCE SIGNS LIST

2: POWER FEEDER LINE
3: OUTFLOW HOLE
4: NOZZLE
4 a: NOZZLE BODY
4 b, 4 b′, 4 b″, 4 b′″: NOZZLE COVER
4 c: NOZZLE BODY TIP PORTION
4 d, 4 d′, 4 d″: CONTACT SURFACE
4 e: TREATMENT LIQUID EJECTION PORT
5: INSOLUBLE ELECTRODE
6: TREATMENT LIQUID
7: SURFACE TREATMENT TARGET MEMBER
8: DC POWER SOURCE
9, 9′: TREATMENT LIQUID CIRCULATION TUBE
10, 10′: CIRCULATION PUMP
11: TREATMENT LIQUID TANK
12, 12′ : SWITCHING VALVE
14: DECOMPRESSING HOLE
15: CONNECTION PORTION BETWEEN DECOMPRESSING HOLE AND VACUUM PUMP
16: VACUUM PUMP
20: ASPIRATOR
100 a, 100 b: WET SURFACE TREATMENT APPARATUS

Claims

1. A wet surface treatment apparatus comprising:

a tank that accommodates a treatment liquid;

a nozzle that ejects the treatment liquid to a surface treatment target member; and

a power source that supplies a current to the nozzle,

wherein the nozzle has a nozzle body which has a flow path of the treatment liquid, a nozzle cover in which one end is connected to a tip of the nozzle body and the other end comes into contact with the surface treatment target member, and a power feeder line through which the current from the power source is supplied to the nozzle body and the nozzle cover.

2. The wet surface treatment apparatus according to claim 1,

wherein the nozzle cover is flexible.

3. The wet surface treatment apparatus according to claim 1,

wherein in the nozzle cover, a surface on which the nozzle cover comes into contact with the surface treatment target member has a decompressing hole.

4. The wet surface treatment apparatus according to claim 1,

wherein the nozzle cover has an outflow hole through which a waste liquid of the treatment liquid is discharged outward of the nozzle cover.

5. The wet surface treatment apparatus according to claim 1,

wherein the power feeder line is exposed on a surface on which the nozzle cover comes into contact with the surface treatment target member, and the power feeder line comes into contact with the surface treatment target member so as to supply the current to the surface treatment target member.

6. The wet surface treatment apparatus according to claim 1,

wherein the flow path of the treatment liquid is formed from an insoluble electrode.

7. The wet surface treatment apparatus according to claim 3,

wherein the nozzle has an aspirator which decompresses an interior of the nozzle cover, and is configured to perform aspiration through the decompressing hole, and

wherein the aspirator decompresses and evacuates the interior of the nozzle cover by using a flow of the treatment liquid ejected from the nozzle.

8. The wet surface treatment apparatus according to claim 2,

wherein the nozzle cover is formed of a resin material having chemical resistance.

9. The wet surface treatment apparatus according to claim 8,

wherein the resin material contains either a silicone resin or a fluorine resin.

10. The wet surface treatment apparatus according to claim 2,

wherein the nozzle cover has a multi-stage bellows shape.

11. The wet surface treatment apparatus according to claim 1, further comprising:

a tube that connects the tank and the nozzle to each other; and

a circulation pump that is disposed in the tube,

wherein a waste liquid of the treatment liquid supplied from the tank to the nozzle is collected to the tank via the tube and the circulation pump.

12. The wet surface treatment apparatus according to claim 3, further comprising:

a vacuum pump that is connected to the decompressing hole,

wherein the decompressing hole is decompressed and evacuated by the vacuum pump so as to bring the nozzle cover and the surface treatment target member into close contact with each other.

13. The wet surface treatment apparatus according to claim 1,

wherein the treatment tank accommodates a plurality of different treatment liquids.

14. The wet surface treatment apparatus according to claim 6,

wherein a polarity of the insoluble electrode is changed by the power source.

15. The wet surface treatment apparatus according to claim 1,

wherein the surface treatment target member is a large structure member fixed onto the land.

16. The wet surface treatment apparatus according to claim 15,

wherein the large structure member is a structure member of a bridge or a power plant.