WO2018062259A1 - Workpiece holding jig and surface treatment device - Google Patents

Abstract

A workpiece holding jig that has: a conductive frame-like member 630; a plurality of conductive first chuck members 610 that are supported on an upper frame member 631 and grip an upper side of a rectangular workpiece 20; a plurality of conductive second chuck members 620 that are supported on a lower frame member 632 and grip a lower side of the rectangular workpiece; a shared power supply part 650; a first conduction part 660 that conducts electricity from the shared power supply part to the upper frame member; and a second conduction part 670 that conducts electricity from the shared power supply part to a pair of vertical frame members 633, 634. The first conduction member is electrically connected and fixed to both end parts of the upper frame member and includes: a pair of first conduction members 661, 662 that, via an insulation member 635, respectively guide the pair of vertical frame members such that the pair of vertical frame members are capable of vertical movement; and a pair of second conduction members 663, 664 that electrically connect the shared power supply part and the pair of first conduction members.

Description

Work holding jig and surface treatment apparatus

The present invention relates to a workpiece holding jig and a surface treatment apparatus used in a surface treatment apparatus such as a continuous plating apparatus.

In a surface treatment apparatus such as a continuous plating apparatus, the work is suspended and held by a work holding jig, and the work is continuously conveyed in the liquid in the surface treatment tank. As shown in Patent Document 1, for example, the workpiece holding jig generally holds the workpiece by chucking the upper end of the workpiece and hanging the workpiece.

Also, another function of the workpiece holding jig is to set the workpiece to the cathode (cathode) with respect to the anode (anode) arranged in the surface treatment tank. An electric field is formed between the cathode and the anode, and the plating solution is electrolyzed to plate the workpiece surface. Therefore, the chuck member that chucks the upper end of the workpiece is formed of a conductive member, and the workpiece is set as a cathode via a workpiece holding jig.

However, there is a limit to ensuring in-plane uniformity of the surface treatment of the workpiece only by securing the energization route at the upper end of the workpiece. Therefore, the applicant of the present application has developed a workpiece holding jig that supplies power from the vertical direction of the workpiece via a chuck member that chucks the upper and lower ends of the workpiece (Patent Document 2).

JP 2009-132958 A Japanese Patent No. 5898540

According to the technique disclosed in Patent Document 2, it is possible to improve the in-plane uniformity of the current distribution of the workpiece. However, for example, the resistance difference of the energization route for energizing the upper and lower ends of the workpiece can be further reduced, or the workpiece It is desired to further improve the in-plane uniformity by reducing the resistance difference of the energization route for energizing the front and back surfaces.

Some aspects of the present invention can further reduce the resistance difference of the energization route for energizing the upper and lower ends of the work or the front and back surfaces, and further improve the in-plane uniformity of the work current distribution. An object is to provide a tool and a surface treatment apparatus.

(1) One aspect of the present invention is a workpiece holding jig for holding a rectangular workpiece in a vertical state in a processing liquid in a processing tank, and setting the workpiece as a cathode,
A conductive frame-like member disposed to surround the workpiece, including a horizontal frame member including an upper frame member and a lower frame member, and a pair of vertical frame members electrically connected to the lower frame member; ,
A plurality of conductive first chuck members supported by the upper frame member and gripping the upper side of the workpiece;
A plurality of conductive second chuck members supported by the lower frame member and gripping the lower side of the workpiece;
A common power supply;
A first energization unit for energizing the upper frame member from the common power supply unit;
A second energization unit having a resistance value smaller than that of the first energization unit, energizing the pair of vertical frame members from the common power supply unit;
Have
The first energization unit includes:
A pair of first conductive members that are electrically connected and fixed to both ends of the upper frame member, and that guide the pair of vertical frame members to move up and down through insulating members;
A pair of second conductive members that electrically connect the common power feeding portion and the pair of first conductive members;
It is related with the workpiece holding jig containing.

According to one aspect of the present invention, the plurality of first chuck members are energized from the common power supply unit via the pair of first and second conductive members that are the first energization unit and the upper frame member. The plurality of second chuck members are energized from the power supply unit through the second energization unit having a smaller resistance value than the first energization unit, the pair of vertical frame members, and the lower frame member.

Here, the first energization section does not directly energize the upper frame member directly by the shortest route as in Patent Document 2, but via a pair of first and second conductive members that also serve as lifting guides for the pair of vertical frame members. Is energized. Therefore, it becomes easy to set the resistance value of the first energization part substantially equal to the total resistance value of the second energization part and the pair of vertical frame members. Thereby, the current flowing from the plurality of first chuck members to the workpiece and the current flowing from the plurality of second chuck members to the workpiece can be made substantially equal, and the in-plane uniformity of the current distribution of the workpiece can be further improved. Further, the pair of first conductive members that are electrically connected and fixed to both ends of the upper frame member are also used as members that guide the pair of vertical frame members so as to move up and down through the insulating member. . As a result, the lower frame member supported by the pair of vertical frame members and the plurality of second chuck members move downward by their own weight to apply tension to the workpiece, and in particular prevent bending that may occur in the thin plate-like workpiece. can do. In addition, since the upper frame member, the pair of first conductive members, and the pair of vertical frame members are electrically insulated by the insulating member, the energization routes of the first and second energization portions are electrically insulated. Can do.

(2) In one aspect of the present invention, each of the pair of second conductive members is formed redundantly, bypassing each shortest route between each of the pair of first conductive members and a common power feeding unit. be able to. In this way, it becomes easier to set the resistance value of the first energization part substantially equal to the total resistance value of the second energization part and the pair of vertical frame members.

(3) In one aspect of the present invention, each of the pair of first conductive members is provided with a vertically long hole, and each of the pair of vertical frame members is provided with the insulating member guided along the vertically long hole. it can. This increases the resistance value of the pair of first conductive members having the longitudinal holes, so that the resistance value of the first energization unit is set to be approximately equal to the total resistance value of the second energization unit and the pair of vertical frame members. Is even easier.

(4) In one aspect of the present invention, the second current-carrying part may include two conductive cables that electrically connect the common power feeding part and the upper ends of the pair of vertical frame members. Thus, by reducing the resistance value of the second energization part, it becomes easier to set the resistance value of the first energization part substantially equal to the total resistance value of the second energization part and the pair of vertical frame members.

(5) In one aspect of the present invention,
The workpiece holding jig is for processing both surfaces of the workpiece by energizing the workpiece,
Each of the plurality of first chuck members and the plurality of second chuck members is
A fixed chuck piece fixed to the horizontal frame member;
A movable chuck piece that is slidably supported with respect to the fixed chuck piece;
An elastic member for maintaining the clamping state of the workpiece sandwiched between the fixed chuck piece and the movable chuck piece;
Including
The elastic member may be a conductive leaf spring that is electrically connected and fixed to at least the horizontal frame member and the movable chuck piece.

(6) Another aspect of the present invention is:
A work holding jig for energizing the work to process both sides of the work,
A fixed chuck piece fixed to the conductive member;
A movable chuck piece which is freely movable with respect to the fixed chuck piece;
An elastic member for maintaining a sandwiched state of the workpiece sandwiched between the fixed chuck piece and the movable chuck piece;
Including
The elastic member relates to a work holding jig that is a conductive leaf spring that is electrically connected and fixed to at least the conductive member and the movable chuck piece.

According to the above aspects (5) and (6), the movable chuck piece can be energized from the horizontal frame member (conductive member) via the leaf spring. In general, the movable chuck piece is slidably supported by a shaft portion supported by the fixed chuck piece, and is inserted into the shaft portion of an elastic member that maintains the clamping state of the work sandwiched between the fixed chuck piece and the movable chuck piece. A torsion coil spring is used. In this case, a fixed chuck piece, a shaft portion, and a torsion coil spring are interposed in an energization route between the conductive member and the movable chuck piece. However, the interposition member which is the shaft portion and the torsion coil spring only makes local contact with the fixed chuck piece and the movable chuck piece. Therefore, the resistance value of the energization route from the conductive member to the movable chuck piece through the interposition member is much larger than the resistance value of the energization route from the conductive member to the fixed chuck piece. When energizing both surfaces of the workpiece and surface-treating both surfaces of the workpiece, the uniformity of the treatment on the front and back surfaces of the workpiece could not be ensured due to the above-described difference in resistance value. According to the above aspects (4) and (5), the uniformity of processing on the front and back surfaces of the workpiece can be improved by energizing the movable chuck piece from the electric member via the leaf spring. Moreover, the number of parts does not increase by using the leaf spring that maintains the clamping state of the workpiece sandwiched between the fixed chuck piece 7 and the movable chuck piece as the current-carrying member.

(7) In still another aspect of the present invention,
The leaf spring is
A first fixed portion that is electrically connected and fixed to the movable chuck piece;
A second fixing portion that is electrically connected and fixed to the conductive member;
A pair of arm portions connecting the first fixing portion and the second fixing portion;
Including
Part of the pair of arm portions disposed on both sides of the fixed chuck piece and the movable chuck piece in a plan view may include a U-shaped curved portion.

In this way, the leaf spring has a line-symmetric shape in plan view, and the clamping force of the leaf spring can be made to act evenly in a line-symmetric manner, and the energization route of the leaf spring from the conductive member to the movable chuck piece is also line-symmetric. Can be secured. Thereby, the in-plane uniformity of the current distribution of the workpiece is increased.

(8) In still another aspect of the present invention,
The fixed chuck piece is electrically insulated and fixed to the conductive member;
The leaf spring is
A first fixed portion that is electrically connected and fixed to the movable chuck piece;
A second fixing portion that is electrically connected and fixed to the conductive member;
A third fixing portion that is electrically connected and fixed to the fixing chuck piece;
A pair of arm portions connecting the first fixing portion and the second fixing portion;
Including
The second fixing part is located between the first fixing part and the third fixing part in the longitudinal direction of the leaf spring,
The pair of arm portions may include a U-shaped curved portion, part of which is disposed on both sides of the fixed chuck piece and the movable chuck piece in a plan view.

In this way, since the energization route is formed in line symmetry from the conductive member to the movable chuck piece via the second fixed portion, the pair of arm portions, and the first fixed portion, the in-plane uniformity of the current distribution of the workpiece is increased. . Further, an energization route is formed in the fixed chuck piece from the conductive member electrically insulated from the fixed chuck piece via the second fixed portion and the third fixed portion of the leaf spring. As a result, both the first energization route from the conductive member to the fixed chuck piece and the second energization route from the conductive member to the movable chuck piece are formed by the leaf springs, and the resistance value between the first and second energization routes. Can be made smaller. Thereby, the uniformity of processing on the front and back surfaces of the workpiece can be further improved.

(9) In another aspect of the present invention, a shaft portion that is supported by the fixed chuck piece and supports the movable chuck piece in a swingable manner is provided, and the first fixed portion is positioned more than the position of the shaft portion. The movable chuck piece can be fixed to the movable chuck piece at a position biased toward the chuck end side.

Thus, the leaf spring can move and bias the chuck end of the movable chuck piece toward the fixed chuck piece, and the resistance value of the second energization route via the U-shaped curved portion of the leaf spring can be increased. This can be offset by shortening the distance from the chuck end of the movable chuck piece.

(10) In another aspect of the invention, there is provided a shaft portion that is supported by the fixed chuck piece and movably supports the movable chuck piece, and the first fixed portion has the shaft in the plan view. The third chuck is fixed to the movable chuck piece at a position biased toward the chuck end of the movable chuck piece relative to the position of the part, and the third fixed part is fixed to the fixed chuck from the position of the shaft part in the plan view. It can be fixed to the fixed chuck piece at a position biased to the end side opposite to the chuck end of the piece.

In this way, by increasing the length of the first energization route from the second fixed portion of the leaf spring to the chuck end of the fixed chuck piece through the third fixed portion, the second fixed portion of the leaf spring, the U-shaped The difference between the resistance value of the second energization route and the resistance value of the first energization route from the curved portion and the first fixed portion to the chuck end of the movable chuck piece can be reduced.

(11) Still another aspect of the present invention provides:
A surface treatment tank containing a treatment liquid and having an upper end opening;
The workpiece holding jig according to any one of (1) to (10), wherein the workpiece immersed in the treatment liquid in the surface treatment tank is suspended and held, and the workpiece is set as a cathode.
In the surface treatment tank, an anode electrode disposed at a position facing the workpiece,
Is defined.

It is a longitudinal cross-sectional view of the surface treatment apparatus which concerns on embodiment of this invention. It is the elements on larger scale of FIG. It is a perspective view of the workpiece holding jig of a comparative example. It is a figure which shows two guide rails and the workpiece holding jig of a comparative example. It is a figure which shows the to-be-energized part of the workpiece holding jig which concerns on embodiment of this invention. It is a front view which shows the electricity supply part and workpiece holding part of the workpiece holding jig which concern on embodiment of this invention. FIG. 7A is a diagram showing a part of the supporting structure of the pair of conductive members that guide the pair of vertical frame members so as to be movable up and down, and FIG. 7B is formed on the first conductive member. It is a figure which shows the vertically long hole. It is a figure which shows the 2nd electric power feeding part of patent document 2. FIG. It is a side view of a 1st, 2nd chuck member. It is a top view of the 1st, 2nd chuck member. It is a bottom view of the first and second chuck members. It is a schematic diagram which shows the anode electrode part arrange | positioned at the processing tank of FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are indispensable as means for solving the present invention. Is not limited.

1. Outline of Surface Treatment Apparatus FIG. 1 is a longitudinal sectional view of a surface treatment apparatus such as a continuous plating treatment apparatus. In the continuous plating apparatus 10, a plurality of conveying jigs 30A each holding a workpiece 20 such as a circuit board are circulated and conveyed in a direction perpendicular to the paper surface of FIG. In FIG. 1, two straight conveyance paths 110 and 120 in parallel of the circulation conveyance path 100 are shown. The two straight conveyance paths 110 and 120 are connected at both ends to form a loop-shaped circulation conveyance path 100.

In the circulation conveyance path 100, a plating tank (surface treatment tank in a broad sense) 200 for surface-treating, for example, plating the workpiece 20 held by each of the plurality of workpiece holding jigs 30 </ b> A, and a circulation conveyance path than the plating tank 200 are provided. An unprocessed workpiece 20 provided upstream of 100 and a carry-in portion (not shown) for carrying in a plurality of conveyance jigs 30 </ b> A, and a processed workpiece 20 provided downstream of the circulation conveyance path 100 with respect to the plating tank 200. And an unloading part (not shown) for unloading from the plurality of work holding jigs 30A.

In the present embodiment, the plating tank 200 is provided along the second straight conveyance path 120, and the carry-in part and the carry-out part are provided in the first straight conveyance path 110. The circulation conveyance path 100 further includes a pretreatment tank group 230 disposed on the upstream side of the plating tank 200 and a posttreatment tank group (not shown) disposed on the downstream side of the plating tank 200.

The pretreatment tank group 230 is configured by arranging, for example, a degreasing tank, a hot water washing tank, a water washing tank, a shower tank, and a pickling tank in order from the upstream side between the carry-in portion and the plating tank 200. The post-treatment tank is configured by arranging, for example, a shower tank and a water washing tank in order from the upstream side between the plating tank 200 and the carry-out section. Note that the number and type of the pretreatment tank group 230 and the posttreatment tank group can be changed as appropriate.

As shown in FIG. 1, the continuous plating apparatus 10 has a plating tank (surface treatment tank in a broad sense) 200 that contains a plating liquid Q (treatment liquid in a broad sense) and has an upper end opening 201. The continuous plating apparatus 10 is further parallel to the longitudinal direction of the plating tank 200 at a position off the upper end opening 201 of the plating tank 200, as shown in FIG. For example, two first guide rails 130 and second guide rails 140 are provided that extend along a first direction (a direction perpendicular to the paper surface). The plurality of conveying jigs 30 </ b> A are arranged in the processing solution of the plating tank 200 to hold the workpiece 20 and are supported by the first and second guide rails 130 and 140. There may be one guide rail or three or more guide rails.

As shown in FIG. 3, each of the plurality of workpiece holding jigs 30 </ b> A roughly includes a conveyance unit 300 and a workpiece holding unit 500. In addition, the conveyance part 300 among the workpiece holding jigs 30A shown in FIG. 1 can be shared with the workpiece holding jig 30B of this embodiment described later. The energizing section 330 and the work holding section 500 of the work holding jig 30A shown in FIG. 1 show a comparative example, and the power feeding section 650 and the work holding section 600 of the work holding jig 30B of the present embodiment shown in FIG. Is different.

The work holding jig 30A shown in FIG. The transport unit 300 includes a horizontal arm unit 301, a first guided unit 310, and a second guided unit 320. As shown in FIG. 3, the horizontal arm unit 301 includes, for example, two first and second horizontal arms 301 </ b> A that extend along a second direction B that is orthogonal (crossed in a broad sense) to the first direction (conveying direction) A. , 301B. As shown in FIG. 4, the first guided portion 310 is supported on one end side of the horizontal arm portion 301 and guided to the first guide rail 130. As shown in FIG. 4, the second guided portion 320 is supported on the other end side of the horizontal arm portion 301 and guided to the second guide rail 140.

As shown in FIG. 3, the energization unit 330 is supported by being suspended from the conductive horizontal arm units 301 (301 </ b> A and 301 </ b> B) that are also used as the transport unit 300, the conductive support plate 331, and the support plate 331. For example, it has two conductive vertical arm portions 332A and 332B (332). As shown in FIG. 3, the support plate 331 is fixed to the horizontal arm portion 301 at a position between the first guided portion 310 and the second guided portion 320.

As described above, each of the plurality of jigs 30A includes the first and second guided portions 310 and 320 on both ends in the second direction B across the vertical arm portion 332 that holds the workpiece 20. 2 It has a form of a doubly supported beam supported by the guide rails 130 and 140. Therefore, in the present embodiment, the workpiece 20 can be stably held and conveyed while suppressing vertical movement during the conveyance of the workpiece holding jig 30A. In addition, since the first and second guide rails 130 and 140 and the first and second guided portions 310 and 320 serving as the sliding portions are located away from above the upper end opening 201 of the plating tank 200, dust or the like Does not fall into the plating tank 200 and contaminate the plating solution.

In the plating apparatus 10, the workpiece 20 is a cathode (cathode), and the plating tank 200 accommodates anodes (anodes: for example, copper-based anode balls) 410 </ b> L and 410 </ b> R on both sides of the conveyance path of the workpiece 20. Part) 202 and 203, an electric field is formed between the cathode and the anode to electrolyze the plating solution, and the workpiece 20 is electroplated. Therefore, it is necessary to energize the workpiece 20 that is immersed in the plating solution Q and conveyed. In order to energize the workpiece 20, for example, at least one of the first and second guide rails 130 and 140 can be an energizing rail. In this case, among the members constituting the workpiece holding jig 30A, the material of the path through which the workpiece 20 is energized from the first and second guide rails 130 and 140 through the energization portion 330 may be formed of an electric conductor.

Alternatively, as shown in FIGS. 1 and 2, the plating apparatus 10 can be provided with at least one energizing rail 210 separately from the first and second guide rails 130 and 140. In particular, the current-carrying rail 210 according to the present embodiment has a plurality of, for example, four divided current-carrying rails 210A to 210A, which are insulated from each other, as shown in FIG. 210D. Each of the plurality of workpiece holding jigs 30A has an energized portion 340 (FIGS. 2 and 3) that is energized in contact with any one of the four divided energizing rails 210A to 210D. The energized part 340 is fixed to the horizontal arm part 301 (301 </ b> A, 301 </ b> B) that is a component of the energizing part 330.

Thus, each of the plurality of jigs 30A includes the first and second guide rails 130, 320 on both ends in the second direction B with the energized portion 340 interposed therebetween. It has the form of a double-sided support supported by 140. Therefore, it is possible to stably maintain the contact with the energizing rail 210 while suppressing the vertical movement of the energized portion 340 during the conveyance of the work holding jig 30A.

FIG. 5 shows details of the energized part 340. The energized portion 340 connects the conductive support plate 350 fixed to the horizontal arm portion 301 (301A, 301B) and the conductive contact portion 341 with conductive, for example, two parallel links 342A, 342B. It has a parallel link mechanism 342 of a knot rotation chain. The two links 342A and 342B are constantly urged to move in the clockwise direction by torsion coil springs 343 and 343 which are urging members. As a result, the contact portion 341 can be brought into contact with the energizing rail 210 with an appropriate contact pressure.

Also, the two parallel links 342A and 342B are inclined such that the upper fulcrum precedes and the lower fulcrum follows. As a result, the contact portion 341 travels while being pulled by the conveying jig 30A, and thus travel is stable.

2. As described above, the energizing section 330 of the workpiece holding jig 30A of the comparative example includes the conductive horizontal arm section 301, the conductive support plate 331, and the like as shown in FIG. And conductive vertical arm portions 332A and 332B (332). Further, a workpiece holding unit 500 as a comparative example is suspended and supported by the two vertical arm portions 332A and 332B.

As shown in FIG. 3, the work holding unit 500 includes a plurality of conductive first chuck members 510 that grip the upper side 20 a of the rectangular work 20, and a lower 20 b that faces the upper side 20 a of the rectangular work 20 in the vertical direction C. And a plurality of conductive second chuck members 520 that surround the rectangular workpiece 20 and a plurality of first chuck members 510 and a frame-like member 530 that supports the plurality of second chuck members 520. .

The frame-shaped member 530 includes a conductive upper frame member 531 that supports the plurality of first chuck members 510, a conductive lower frame member 532 that supports the plurality of second chuck members 520, and both ends of the upper frame member 531. And the two vertical frame members 533 and 534 which connect the both ends and the both ends of the lower frame member 532, respectively.

Thus, in the frame member 530 of the comparative example, the upper frame member 531 and the lower frame member 532 are electrically connected by the two vertical frame members 533 and 534. In order to energize the lower frame member 532 from the two vertical arm portions 332A and 332B functioning as the energization portions, the upper frame member 531 was passed. Therefore, conventionally, the resistance value of the energization route to the lower frame member 532 is necessarily larger than the resistance value of the energization route to the upper frame member 531. Therefore, the current distribution in the workpiece 20 has a higher current value on the upper side 20a and a lower current value on the lower side 20b, and the in-plane uniformity is not good.

3. Workpiece holding part according to the present embodiment as a work holding jig 3.1. FIG. 6 shows a work holding jig 30B according to an embodiment of the present invention, and in particular, a configuration different from the work holding jig 30A of the comparative example. The workpiece holding part 600 which has is shown. Note that the workpiece holding jig 30A of the comparative example and the workpiece holding jig 30B of the present embodiment can share the transport unit 300 shown in FIG. The workpiece holding jig 30B in FIG. 6 is different from the workpiece holding jig 30A in FIG. 3 in the structure of the workpiece holding portion 600 including the common power feeding portion 650. Note that the common power feeding unit 650 passes from the contact portion 341 (FIG. 5) in the transport unit 300 shown in FIG. 3 to the work holding unit 600 via the support plate 350, the horizontal arm portions 301 (301A and 301B), and the support plate 331. Connected to the energizing route. FIG. 6 shows an alternative structure to the vertical arm portion 332 (332A, 332B) and the work holding portion 500 shown in FIG. 3, and the common power feeding portion 650 shown in FIG. 6 is connected to the support plate 331 shown in FIG. .

6 includes a plurality of conductive first chuck members 610 that grip the upper side 20a of the rectangular workpiece 20 and a plurality of conductive second chuck members 620 that grip the lower side 20b of the rectangular workpiece 20. And a frame-like member 630 that is disposed around the rectangular workpiece 20 and supports the plurality of first chuck members 610 and the plurality of second chuck members 620, the common power supply unit 650, the first energization unit 660, and the second energization unit. Part 670. In the present embodiment, the work holding unit 600 connects the common power feeding unit 650 and the frame-like member 630 by, for example, two insulating arms 601 and 601.

Here, when a very thin workpiece is a target for surface treatment, when the workpiece 20 is lowered into the processing tank 200 and loaded, the workpiece 20 is transported in the processing tank 200 in the transport direction A of FIG. At this time, the suspended state of the workpiece 20 cannot be maintained due to the hydraulic pressure.

Since the workpiece holding unit 600 of the present embodiment chucks the upper and lower sides 20a and 20b of the workpiece 20, it can hold the vertical posture of the workpiece 20 even when hydraulic pressure is applied. The second chuck member 620 is movable in the vertical direction. This point will be described later.

This embodiment can prevent deformation even with an extremely thin workpiece 20 such that the thickness of the workpiece 20 is 100 μm or less, preferably 60 μm or less. In the present embodiment, the thickness of the workpiece 20 is, for example, 40 μm = 0.04 mm. In addition, since the workpiece holding part 500 of the comparative example also has the upper and lower first and second chuck members 510 and 520, the point that the deformation of the workpiece 20 can be prevented is the same as in the present embodiment.

However, when the frame-shaped member 530 and the first and second chuck members 510 and 520 are made conductive as in the workpiece holding unit 500 of the comparative example, the lower frame member 532 that supports the second chuck member 520 is connected. The resistance value of the energization route is necessarily larger than the resistance value of the energization route to the upper frame member 531 that supports the first chuck member 510. This is because the energization route to the lower frame member 532 always passes through the energization route to the upper frame member 531. Further, when only the upper end of the workpiece is chucked by the holding jig as in the prior art of Patent Document 1, the energization route is limited only to the upper frame member. Therefore, the current (or the flow of electrons in the opposite direction) flowing from the anode to the work and the frame-like member through the liquid becomes easier to flow toward the upper end side of the work chucked by the work holding jig. The current distribution is non-uniform in the work surface. The in-plane uniformity of the workpiece current distribution affects the surface treatment quality of the workpiece.

In the present embodiment, the frame-shaped member 630 disposed so as to surround the rectangular workpiece 20 includes a conductive upper frame member (horizontal frame member) 631 that supports the plurality of first chuck members 610 and a plurality of second chuck members. A conductive lower frame member (horizontal frame member) 632 that supports 620 and a pair of conductive vertical frame members 633 and 634 can be provided. Note that the plurality of first chuck members 610 are the upper frame member (horizontal frame member) 631, and the plurality of second chuck members 620 are the upper frame member (horizontal frame member) 632. They are arranged symmetrically with respect to the vertical axis. In the present embodiment, the first energization unit 660 that supplies power to the upper frame member 631 from the common power supply unit 650 is connected to the pair of first conductive members 661 and 662 provided at both ends of the upper frame member 631. A pair of second conductive members 663 and 664 that electrically connect the portion 650 and the pair of first conductive members 640A and 640B can be provided. The second energization unit 670 that supplies power to the pair of vertical frame members 633 and 634 from the common power supply unit 650 includes, for example, two vertical frame energization cables 671A and 671B.

An energization route from the common power supply unit 650 to the first chuck member 610 via the first energization unit 660 and an energization route from the common power supply unit 650 to the second chuck member 620 via the second energization unit 670 will be described later. The insulation member 640 is electrically insulated and the resistance value can be set independently. Thereby, the in-plane uniformity of the current distribution of the workpiece 20 is improved, and the surface treatment quality of the workpiece 20 is further improved.

In the present embodiment, the plurality of first chuck members 610 and the plurality of second chuck members 620 are electrically insulated. In addition, the energization from the common power supply unit 650 to the first and second chuck members 610 and 620 is also separated into the first and second energization units 660 and 670 that are electrically insulated from each other. The first energization unit 660 energizes the plurality of first chuck members 610 from the common power supply unit 650 via the upper frame member 531 which is a part of the frame-shaped member 630. The second energization unit 670 energizes the plurality of second chuck members 620 from the common power supply unit 650 through a pair of vertical frame members 533 and 534 and a lower frame member 532 which are other parts of the frame-shaped member 630.

Therefore, the energization route from the common power supply unit 650 to the first chuck member 610 via the first energization unit 660 and the energization route from the common power supply unit 650 to the second chuck member 620 via the second energization unit 670 are The resistance value can be set independently. Accordingly, the resistance value of the energization route from the common power supply unit 650 to the plurality of first chuck members 610 and the resistance value of the energization route from the common power supply unit 650 to the plurality of second chuck members 620 are substantially equal. Can be set. As a result, the in-plane uniformity of the current distribution of the workpiece 20 can be improved, and the surface treatment quality of the workpiece 20 can be further improved.

In particular, in the present embodiment, the first energization unit 660 that energizes the upper frame member 631 from the common power supply unit 650 includes a pair of first conductive members 661 and 662 and a pair of second conductive members 663 and 664. The pair of first conductive members 661 and 662 are electrically connected and fixed to both end portions of the upper frame member 631, and the pair of vertical frame members 533 and 534 can be moved up and down via insulating members 640 described later. invite. The pair of second conductive members 663 and 664 electrically connect the common power feeding unit 650 and the pair of first conductive members 661 and 662. Thus, the 1st electricity supply part 660 is formed redundantly. Further, each of the pair of second conductive members 663 and 664 is redundantly formed by bypassing each shortest route between each of the pair of first conductive members 661 and 662 and the common power feeding unit 650. In the present embodiment, each of the pair of second conductive members 663 and 664 is connected to the vertical piece 665 whose upper end is connected to the common power feeding unit 650 and one end is connected to one of the pair of first conductive members 661 and 662. It has a horizontal piece 666 and an inclined piece 667 that connects the lower end of the vertical piece 665 and the other end of the horizontal piece 666 and is formed redundantly.

Here, according to FIG. 6 of Patent Document 2, the first energization unit 660 directly energizes the upper frame member 631 from the common energization units 301 </ b> A and 301 </ b> B, and some components of the first energization unit 660. The conductive connection portions 662 (662A, 662B) are linearly directed downward vertically, which is the shortest route between the insulating connection portions 661 supporting the common energization portions 301A, 301B and the upper frame member 631. It extends to. In contrast, as shown in FIG. 6, the first energization unit 660 of the present embodiment does not directly supply power to the upper frame member 631 from the common power supply unit 650, and the pair of first conductive members 661 and 662 are connected. Power is supplied to the upper frame member 631 through the interposition. In addition, the pair of second conductive members 663 and 664 that feed power from the common power feeding unit 650 to the pair of first conductive members 661 and 662 are redundantly formed as described above. Therefore, the first energization unit 660 of this embodiment can easily set the resistance value of the power supply path from the common power supply unit 650 to the upper frame member 631 to be larger than the first energization unit 660 of Patent Document 2. it can.

On the other hand, both the patent document 2 and the present embodiment are common in that the second energization unit 670 includes two vertical frame energization cables 671A and 671B. However, in the second energization portion 670 of Patent Document 2, the vertical frame energization cable 671A (671B) is connected to the vertical frame member 633 (634) via the compression coil spring 643 and the fixing member 644, as shown in FIG. Has been. The fixing member 644 fixes the vertical frame energization cables 671A and 671B to the insulating guide member 641 fixed to the upper frame member 631. The insulating guide member 641 has two horizontal pieces 641B and 641C connected to the vertical piece 641A, and the vertical frame energizing cables 671A and 671B are fixed to the horizontal piece 641C by bolts 644A, nuts 644B and washers 644C and 644D. Below the horizontal piece 641B, an insulating cylindrical member 642 for guiding the upper end portion 633A (634A) of the vertical frame member 633 (634) to move up and down is provided. The upper end 633A (634A) has a flange 633B (634B) at a position that is inserted through the hole 642A of the insulating cylindrical member 642 and protrudes upward from the horizontal piece 641B. The compression coil spring 643 is disposed between the washer 644D and the flange 633B (634B), and applies tension to the workpiece 20 by pushing down the vertical frame member 633 (634). Therefore, the second energization unit 670 is more effective in the present embodiment than in Patent Document 2 in which the compression coil spring 643 is required in the power supply path from the common power supply unit 650 to the pair of vertical frame members 633 and 634. The resistance value can be easily set small.

From the above, the resistance value in the first energization unit 660 of the present embodiment can be set substantially equal to the total resistance value of the second energization unit 670 and the vertical frame member 633 (634). Accordingly, the resistance value of the energization route from the common power supply unit 650 to the plurality of first chuck members 610 and the resistance value of the energization route from the common power supply unit 650 to the plurality of second chuck members 620 are substantially equal. Can be set.

3.2. Support structure capable of raising and lowering a pair of vertical frame members The pair of vertical frame members 633 and 634 are supported by the pair of first conductive members 661 and 662 so as to be movable up and down. FIG. 7A shows a support structure that can be raised and lowered, and FIG. 7B shows at least one, for example, two longitudinal holes 661A formed in the first conductive member 661. Similarly, the first conductive member 662 is provided with a vertically long hole 662A (see FIG. 7A).

FIG. 7A shows a vertical frame member 634 supported by the first conductive member 662 so as to be movable up and down. The vertical frame member 633 is also supported by the first conductive member 661 by the same support structure as that in FIG. The vertical frame member 664 includes an insulating member 635 that is guided along a vertical elongated hole 662 </ b> A formed in the first conductive member 662. The insulating member 635 allows the vertical frame member 664 to move up and down along the vertically long hole 662A formed in the first conductive member 662 and is electrically insulated from the first conductive member 662.

The insulating member 635 can include, for example, a shaft portion 635B with a flange 635A and an insulating washer 635C. The flange 635A is disposed between the vertical frame member 634 and the first conductive member 662, and the shaft portion 635B is inserted into the vertical elongated hole 662A. The shaft length of the shaft portion 635 </ b> B is set to be longer than the thickness t of the first conductive member 662. An insulating washer 635C is disposed on the free end surface of the shaft portion 635B that slightly protrudes from the vertically long hole 662A. In this state, the insulating member 635 is fixed to the vertical frame member 634. For example, a fastener 636 such as a screw, a tapping screw, or a bolt is fastened to the vertical frame member 634 via holes formed in the insulating washer 635C, the shaft portion 635B, and the flange 635A.

As shown in FIG. 7A, the shaft portion 635B of the insulating member 635 has a degree of freedom to move up and down along the vertically long hole 662A. Therefore, the vertical frame member 634 moves within the range of the vertically long hole 662A by the dead weights of the vertical frame member 634, the lower frame member 632, and the second chuck member 620, whereby tension can be applied to the workpiece 20. In order not to bend the workpiece 20 that is moved in the liquid, the tension applied to the workpiece 20 is sufficient by the weight of the vertical frame member 634, the lower frame member 632, and the second chuck member 620. Therefore, in this embodiment, an elastic member such as a spring that applies tension to the workpiece 20 is not necessary.

7A is an advantage of the lifting support structure shown in FIG. 7A in that processing for increasing the electrical resistance of the vertical frame members 633 and 634 is unnecessary or minimized. This is because when screws or bolts are used as the fasteners 636, the vertical frame members 633 and 634 need only be provided with screw holes, and screws or bolts are screwed into the screw holes. When a tapping screw is used as the fastener 636, it is only necessary to provide a lower hole in the vertical frame members 633 and 634, and the tapping screw is screwed into the lower hole. In addition, when the flange 635A of the insulating member 635 is fixed to the vertical frame members 633 and 634 by bonding or the like, the processing of the vertical frame members 633 and 634 becomes unnecessary.

Here, the second energization unit 670 and the vertical frame members 633 and 634 are conductive members disposed between the common power supply unit 650 and the lower frame member 632, and the common power supply unit 650 and the upper frame member 631 are connected to each other. It is required to have the same electrical resistance as that of the first energization unit 660 disposed therebetween. For this purpose, it is necessary to reduce the electrical resistance of the vertical frame members 633 and 634. In the present embodiment, the vertical frame members 633 and 634 have, for example, a constant rectangular cross section over the entire length, and it is not necessary to provide a deformed cross section that increases the electrical resistance by providing a long hole or a spring.

3.3. Chuck Structure The structure of the first and second chuck members 610 and 620 will be described with reference to FIGS. In the present embodiment, as shown in FIGS. 9 to 11, each of the plurality of first chuck members 610 and the plurality of second chuck members 620 includes a horizontal frame member 700 (an upper frame member 631 or a lower frame) which is a conductive member. A fixed chuck piece 710 fixed to the member 632), and a movable chuck piece 720 movable with respect to the fixed chuck piece 710. The movable chuck piece 720 is slidably supported by a shaft portion 740 supported by the fixed chuck piece 710. As shown in FIG. 9, the workpiece 20 can be held between the chuck ends 711 and 721 when the chuck end 711 of the fixed chuck piece 710 and the chuck end 721 of the movable chuck piece 720 are closed. By operating the operating portion 722 located on the opposite side of the chuck end 721 with respect to the shaft portion 740 and moving the chuck end 721 away from the chuck end 711, the clamping state of the workpiece 20 can be released.

The workpiece 20 is clamped by the fixed chuck piece 710 that comes into contact with, for example, the front surface of the workpiece 20 and the movable chuck piece 720 that comes into contact with, for example, the back surface of the workpiece 20. The clamping state of the workpiece 20 can be maintained by the elastic member 730. In the present embodiment, the elastic member 730 is a conductive leaf spring that is electrically connected and fixed to at least the horizontal frame member 700 (upper frame member 631 or lower frame member 632) and the movable chuck piece 720. Can do.

Here, a torsion coil spring that is inserted into the shaft portion 740 is generally used as the elastic member that maintains the workpiece sandwiched between the fixed chuck piece 710 and the movable chuck piece 720. In this case, the fixed chuck piece 710, the shaft portion 740, and the torsion coil spring are interposed in the energization route between the conductive member 700 and the movable chuck piece 720. However, the interposition member which is the shaft portion 740 and the torsion coil spring only makes local contact with the fixed chuck piece 710 and the movable chuck piece 720. Therefore, the resistance value of the second energization route from the conductive member 700 to the movable chuck piece 720 through the interposition member is significantly larger than the resistance value of the first energization route from the conductive member 700 to the fixed chuck piece 710. In the case where both surfaces of the workpiece 20 are energized and both surfaces of the workpiece 20 are surface-treated, the uniformity of the treatment on the front and back surfaces of the workpiece 20 cannot be ensured due to the above-described difference in resistance value. According to the structure of the present embodiment, the conductive chuck 700 is energized from the conductive member 700 (the upper frame member 631 or the lower frame member 632) via the leaf spring 730, so that the processing on the front and back surfaces of the workpiece 20 is uniform. Can be improved. In addition, the number of parts does not increase by using the leaf spring 730 that maintains the clamped state of the workpiece 20 sandwiched between the fixed chuck piece 710 and the movable chuck piece 720 as an energizing member.

Here, the leaf spring 730 has at least a first fixing portion 731, a second fixing portion 732, and a pair of arm portions 733 A and 733 B that connect the first fixing portion 731 and the second fixing portion 732. it can. The first fixing portion 731 of the leaf spring 730 is electrically connected to the movable chuck piece 720 by a bolt 750 and fixed. The second fixing portion 732 of the leaf spring 730 is connected to the conductive member 700 (upper frame member 631 or lower frame member 632) by the bolt 751 and, if necessary, the conductive plates 752 and 753 on the front and back sides of the second fixing portion 732. , Electrically conductive and fixed. A conductive or insulating plate 754 may be provided between the conductive member 700 and the fixed chuck piece 71. When the plate 754 is an insulating plate, the third fixing portion 733 of the leaf spring 730 can be electrically connected to the fixed chuck piece 710 and fixed as shown in FIG. 9 or FIG. However, when the plate 754 is a conductive plate or when the plate 754 is not provided, the third fixing portion 733 is not necessarily provided. This is because the fixed chuck piece 710 is electrically connected to the conductive member 700 without passing through the third fixed portion 733. In either case, the pair of arm portions 733A and 733B are partially arranged on both sides of the fixed chuck piece 710 and the movable chuck piece 720 in the plan view shown in FIG. 10 or FIG. A curved portion curved in a U shape is formed.

In this way, the plate spring 730 has a line-symmetric shape in plan view, and the clamping force of the plate spring 730 can be applied evenly in a line-symmetric manner, and the energization route of the plate spring 730 from the conductive member 700 to the movable chuck piece 720. Can also be secured in line symmetry. Thereby, the in-plane uniformity of the current distribution of the workpiece 20 is enhanced.

Here, in the example shown in FIG. 9, the second fixing portion 732 is located between the first fixing portion 731 and the third fixing portion 733 in the longitudinal direction when the leaf spring 730 is deployed. An energization route is formed in the fixed chuck piece 710 from the conductive member 700 electrically insulated from the fixed chuck piece 710 through the second fixed portion 732 and the third fixed portion 733 of the leaf spring 730. Thus, both the first energization route from the conductive member 700 to the fixed chuck piece 710 and the second energization route from the conductive member 700 to the movable chuck piece 720 are formed by the plate spring 730, and the first and second energization routes are formed. The difference in resistance value between the routes can be further reduced. Thereby, the uniformity of processing on the front and back surfaces of the workpiece 20 can be further improved.

In this embodiment, as is clear from FIGS. 9 and 10, the first fixing portion 731 is provided at a position that is biased toward the chuck end 721 side of the movable chuck piece 720 in the plan view. ing. Accordingly, the chuck end 721 of the movable chuck piece 720 can be moved and urged toward the fixed chuck piece 710 by the plate spring 730. In addition, the increase in the resistance value of the second energization route via the U-shaped curved portions of the pair of arm portions 733A and 733B of the leaf spring 730 is increased from the first fixed portion 731 to the chuck end 721 of the movable chuck piece 720. It can be offset or mitigated by shortening the distance.

Further, in the present embodiment, as is apparent from FIGS. 9 and 11, in a plan view, the position of the shaft portion 740 is biased toward the end opposite to the chuck end 711 of the fixed chuck piece 710. A third fixing portion 733 is provided. In this way, the length of the first energization route from the second fixing portion 732 of the leaf spring 730 to the chuck end 711 of the fixed chuck piece 710 through the third fixing portion 733 can be increased. Accordingly, the resistance of the second energization route from the second fixed portion 732 of the leaf spring 730, the U-shaped curved portion of the pair of arm portions 733A and 733B, and the chuck end of the movable chuck piece 720 through the first fixed portion 731. The difference between the value and the resistance value of the first energization route can be reduced.

4). Anode Electrode for Improving In-Plane Uniformity of Current Distribution in Workpiece FIG. 12 schematically shows anode electrodes (anodes) 410R (410L) arranged on both sides of the conveyance path of the workpiece 20 shown in FIG. . The anode electrode 410R (410L) is energized from an anode bar 400 extending along the longitudinal direction of the processing bath 200. Normally, the anode electrode 410R (410L) is directly connected to the anode bar 400. However, in this embodiment, the insulator bar 430 is interposed between the anode bar 400 and the anode electrode 410R (410L) to thereby connect the anode bar 400. An anode electrode 410R (410L) is fixed to the substrate. A relay energization section 420 that hangs down from the anode bar 400 is provided. The contact member 420A at the lower end of the relay energization unit 420 is provided at a position lower than the liquid level Q1 of the processing liquid Q in the processing tank 200. The contact member 420A is connected to, for example, an intermediate position in the vertical direction of the anode electrode 410R (410L) and configured to energize the anode electrode 410R (410L).

The intermediate position in the vertical direction of the anode electrode 410R (410L) to which the relay energization section 420 is connected is preferably a position that bisects the vertical dimension of the work 20 held by the work holding jig 30B. When a plurality of types having different vertical dimensions are used as the workpiece 20, the vertical position of the contact member 420A can be adjusted by using a known lifting mechanism for the relay energization unit 420. The contact member 420A can be brought into contact with the anode electrode 410R (410L) with a predetermined length in a direction perpendicular to the paper surface of FIG.

In the anode electrode 410R (410L), the current from the contact member 420A flows over the anode electrode 410L (410R) when crying and flowing to the workpiece 20 as the cathode (cathode) via the treatment liquid in the treatment tank 200. The flow branches from the height position of the contact member 420A into an upward direction E1 and a downward direction E2. The anode electrode 410R (410L) shown in FIG. 9 is used in combination with the workpiece holding jig 30B having the workpiece holding portion 600 described above, so that the workpiece 20 facing the relay energization portion 420 of the anode electrode 410R (410L) is used. The current flows uniformly from the vertical center position to the first chuck member 610 and the second chuck member 620 on the cathode side, and the current flowing to the workpiece 20 is improved in the non-uniformity of the current distribution in the vertical direction. Is done.

Although the present embodiment has been described in detail as described above, it will be readily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term described at least once together with a different term having a broader meaning or the same meaning in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. All combinations of the present embodiment and the modified examples are also included in the scope of the present invention.

For example, the energization unit 330 of the jig 30B can connect the energized unit 340 and the common power supply unit 650 with a cable without passing through the horizontal arm unit 301 or the like.

10 surface treatment device (continuous plating treatment device), 20 workpiece, 20a upper side,
20b Lower side, 30A, 30B Work holding jig, 200 Surface treatment tank (plating tank),
201 upper end opening, 210 energizing rail, 210A to 210D split energizing rail,
301, 301A, 301B first and second horizontal arms, 340 energized parts,
410L, 410R anode electrode, 600 workpiece holding part, 610 first chuck member,
620 Second chuck member, 630 Frame member,
631 Upper frame member (horizontal frame member, conductive member), 632 Lower frame member (horizontal frame member, conductive member), 633, 634 A pair of vertical frame members, 635 insulating member, 640 insulating member,
641 insulating plate, 642 insulating pin, 643 retaining flange, 650 common power feeding part,
660 1st energization part, 661,662 A pair of 1st conductive members,
663, 664 a pair of second conductive members, 670 second energization unit,
671A, 671B Vertical frame energizing cable, 700 conductive members (upper frame member, lower frame member),
710 fixed chuck piece, 711 chuck end, 720 movable chuck piece,
721 chuck end, 730 elastic member (plate spring), 731 first fixing portion,
732 second fixing portion, 733A, 733B a pair of arm portions, 740 shaft portion,
A first direction (conveying direction), B second direction, C vertical direction, Q treatment liquid (plating liquid),
Q1 liquid level

Claims (11)

1. A workpiece holding jig for holding a rectangular workpiece in a vertical state in a processing solution in a processing tank, and setting the workpiece as a cathode,
   A conductive frame-like member disposed to surround the workpiece, including a horizontal frame member including an upper frame member and a lower frame member, and a pair of vertical frame members electrically connected to the lower frame member; ,
   A plurality of conductive first chuck members supported by the upper frame member and gripping the upper side of the workpiece;
   A plurality of conductive second chuck members supported by the lower frame member and gripping the lower side of the workpiece;
   A common power supply;
   A first energization unit for energizing the upper frame member from the common power supply unit;
   A second energization unit having a resistance value smaller than that of the first energization unit, energizing the pair of vertical frame members from the common power supply unit;
   Have
   The first energization unit includes:
   A pair of first conductive members that are electrically connected and fixed to both ends of the upper frame member, and that guide the pair of vertical frame members to move up and down through insulating members;
   A pair of second conductive members that electrically connect the common power feeding portion and the pair of first conductive members;
   A workpiece holding jig comprising:
2. In the workpiece holding jig according to claim 1,
   Each of the pair of second conductive members is formed redundantly, bypassing each shortest route between each of the pair of first conductive members and a common power feeding portion. .
3. In the workpiece holding jig according to claim 1 or 2,
   A vertically long hole is provided in each of the pair of first conductive members,
   Each of the pair of vertical frame members is provided with the insulating member guided along the vertical elongated hole.
4. In the workpiece holding jig according to any one of claims 1 to 3,
   The work holding jig, wherein the second energization unit includes two conductive cables that electrically connect the common power supply unit and the upper ends of the pair of vertical frame members.
5. In the workpiece holding jig according to any one of claims 1 to 4,
   The workpiece holding jig is for processing both surfaces of the workpiece by energizing the workpiece,
   Each of the plurality of first chuck members and the plurality of second chuck members is
   A fixed chuck piece fixed to the horizontal frame member;
   A movable chuck piece that is slidably supported with respect to the fixed chuck piece;
   An elastic member for maintaining the clamping state of the workpiece sandwiched between the fixed chuck piece and the movable chuck piece;
   Including
   The work holding jig, wherein the elastic member is a conductive leaf spring that is electrically connected and fixed to at least the horizontal frame member and the movable chuck piece.
6. A work holding jig for energizing the work to process both sides of the work,
   A fixed chuck piece fixed to the conductive member;
   A movable chuck piece which is freely movable with respect to the fixed chuck piece;
   An elastic member for maintaining the clamping state of the workpiece sandwiched between the fixed chuck piece and the movable chuck piece;
   Including
   The work holding jig, wherein the elastic member is a conductive leaf spring that is electrically connected and fixed to at least the conductive member and the movable chuck piece.
7. In the workpiece holding jig according to claim 6,
   The leaf spring is
   A first fixed portion that is electrically connected and fixed to the movable chuck piece;
   A second fixing portion that is electrically connected and fixed to the conductive member;
   A pair of arm portions connecting the first fixing portion and the second fixing portion;
   Including
   The workpiece holding jig, wherein the pair of arm portions includes a U-shaped curved portion in a part disposed on both sides of the fixed chuck piece and the movable chuck piece in a plan view.
8. In the workpiece holding jig according to claim 6,
   The fixed chuck piece is electrically insulated and fixed to the conductive member;
   The leaf spring is
   A first fixed portion that is electrically connected and fixed to the movable chuck piece;
   A second fixing portion that is electrically connected and fixed to the conductive member;
   A third fixing portion that is electrically connected and fixed to the fixing chuck piece;
   A pair of arm portions connecting the first fixing portion and the second fixing portion;
   Including
   The second fixing part is located between the first fixing part and the third fixing part in the longitudinal direction of the leaf spring,
   The workpiece holding jig, wherein the pair of arm portions includes a U-shaped curved portion in a part disposed on both sides of the fixed chuck piece and the movable chuck piece in a plan view.
9. In claim 7 or 8,
   A shaft portion that is supported by the fixed chuck piece and supports the movable chuck piece in a swingable manner;
   The first holding portion is fixed to the movable chuck piece at a position biased toward the chuck end side of the movable chuck piece from the position of the shaft portion in the plan view. jig.
10. In claim 8,
    A shaft portion that is supported by the fixed chuck piece and supports the movable chuck piece in a swingable manner;
    The first fixed portion is fixed to the movable chuck piece at a position biased toward the chuck end side of the movable chuck piece from the position of the shaft portion in the plan view,
    The third fixed portion is fixed to the fixed chuck piece at a position that is biased toward the end opposite to the chuck end of the fixed chuck piece from the position of the shaft portion in the plan view. A workpiece holding jig.
11. A surface treatment tank containing a treatment liquid and having an upper end opening;
    The workpiece holding jig according to any one of claims 1 to 10, wherein a rectangular workpiece immersed in the treatment liquid in the surface treatment tank is suspended and held, and the workpiece is set as a cathode. ,
    In the surface treatment tank, an anode electrode disposed at a position facing the workpiece,
    A surface treatment apparatus comprising:
    

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