Plating apparatus and plating method

Abstract

To provide a plating device and a plating method capable of uniformizing a current density distribution even on a large substrate and thereby obtaining a plated film having a uniform film thickness.SOLUTION: The present invention relates to a plating device and a plating method for plating at least one main surface of a rectangular substrate. The plating device of the present invention comprises: a holding part for holding a substrate in a horizontal attitude with one main surface facing upward in a processing tank; a cathode electrode in contact with a peripheral portion of one main surface of the substrate held by the holding part; an anode electrode part disposed above the substrate held by the holding part and having a lower surface disposed to face one main surface; and a power supply part connected to the anode electrode part and the cathode electrode. The anode electrode part has a first electrode facing a central portion of one main surface and a second electrode facing a portion on an outer side of one main surface. The power supply part has a plurality of current output parts capable of individually setting output currents, and the first electrode and the second electrode are connected to different current output parts.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a plating apparatus and a plating method for plating at least one main surface of a rectangular substrate such as a printed wiring board or a glass substrate, for example.

Background Art

[0002] Techniques for forming a metal thin film by plating on the surface of various substrates such as semiconductor substrates, printed wiring boards, and glass substrates are widely used. For example, Patent Document 1 discloses a plating apparatus for forming a metal film on the surface of a semiconductor wafer as a substrate to be plated. In this plating apparatus, the substrate is held by a jig provided with a cathode electrode, an anode electrode is disposed opposite to the substrate, and an electrolytic plating process is realized by applying a voltage between the two electrodes.

[0003] In this type of electrolytic plating process, due to the non-uniformity of the current distribution, the film thickness of the plating film tends to be larger at the peripheral portion of the substrate than at the central portion. In the above prior art, a shielding plate that shields the current flowing toward the peripheral portion of the substrate is provided in the current path between the anode electrode and the substrate, thereby achieving uniformization of the current density distribution on the substrate surface.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, the size of substrates has been increasing, and for example, large substrates with a side length exceeding 1 meter are being manufactured. The shielding plates corresponding to such large substrates are naturally large in size. Also, in large substrates, the difference in current between the central part and the peripheral part tends to be large, making it very difficult to design a shielding plate to obtain a uniform current distribution. Furthermore, in glass substrates for display devices, etc., a plurality of substrates with slightly different outer dimensions are being produced, and it is practically difficult to prepare optimized shielding plates for each of them.

[0006] For these reasons, even for large substrates, there is a need for a technology that can correct the difference in current density between the central part and the peripheral part of the substrate and achieve uniform current density distribution within the plane of the substrate. In particular, it is desirable to have a technology that can achieve a uniform current density distribution for each of the substrates with different sizes.

[0007] This invention has been made in view of the above problems, and an object thereof is to provide a plating apparatus and a plating method that can uniformize the current density distribution even for large substrates and thereby obtain a plating film with a uniform film thickness.

Means for Solving the Problems

[0008] One aspect of the present invention is a plating apparatus for plating at least one main surface of a rectangular substrate, comprising a treatment tank for storing a plating solution, a holding part for holding the substrate in a horizontal posture with the one main surface facing upward in the treatment tank, a cathode electrode that contacts the peripheral part of the one main surface of the substrate held by the holding part, an anode electrode part disposed above the substrate held by the holding part with the lower surface facing the one main surface, and a power supply part connected to the anode electrode part and the cathode electrode.

[0009] Here, the anode electrode portion has at least one first electrode facing a central portion inside the peripheral portion of the one main surface, and at least one second electrode facing the one main surface outside the central portion, the power supply unit has a plurality of current output units capable of individually setting and changing the output current, and the first electrode and the second electrode are connected to different ones of the current output units.

[0010] Another aspect of the present invention is a plating method for plating at least one main surface of a rectangular substrate. In a processing tank for storing a plating solution, with the one main surface in a horizontal posture facing upward By the holding part a step of holding the substrate, a step of bringing a cathode electrode into contact with a part of the one main surface of the substrate held by the holding portion, and at the same time arranging an anode electrode portion facing the one main surface above the substrate, and a step of outputting a current from a power supply unit connected between the anode electrode portion and the cathode electrode.

[0011] Here, the anode electrode portion has at least one first electrode facing a central portion inside the peripheral portion of the one main surface, and at least one second electrode facing the one main surface outside the central portion, and the power supply unit outputs the current from each of the current output units capable of individually setting and changing the output current and different from each other to the first electrode and the second electrode.

[0012] In the invention configured in this way, the anode electrode portion has a first electrode facing the central portion of the substrate and a second electrode facing the substrate outside this. And individual current output units are connected to each of the first electrode and the second electrode, and the output current of each current output unit can be set individually.

[0013] With such a configuration, it is possible to individually adjust the current density distribution in the central portion of the substrate and the current density distribution in the peripheral portion. Therefore, for example, when there is a tendency for the current density to be higher in the peripheral portion of the substrate than in the central portion, by increasing the input current to the first electrode facing the central portion or, conversely, by decreasing the input current to the second electrode, the difference in current density between the central portion and the peripheral portion can be reduced, and the current density distribution can be made uniform.

[0014] Also, simply applying a predetermined voltage between the first electrode and the second electrode does not always result in a desired current distribution. In contrast, in the present invention, since the current applied to the electrodes is set, that is, the power supply unit outputs a predetermined current, it is possible to directly control the current distribution in each part of the substrate.

Advantages of the Invention

[0015] As described above, according to the present invention, by equalizing the density distribution of the current flowing from the anode electrode toward the substrate, it is possible to make the thickness of the film formed on one main surface of the substrate uniform by electrolytic plating treatment.

Brief Description of the Drawings

[0016]

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Mode for Carrying Out the Invention

[0017] Hereinafter, specific embodiments of the plating apparatus according to the present invention will be described with reference to specific embodiments.

[0018] FIG. 1 is a diagram showing the schematic configuration of an embodiment of a plating apparatus according to the present invention. This plating apparatus 1 is an apparatus for forming a film of metal (for example, gold) by electrolytic plating on at least one main surface of various substrates S such as semiconductor substrates, printed wiring boards, and glass substrates (hereinafter simply referred to as "substrates"). For the following description, an XYZ orthogonal coordinate system is defined as shown in FIG. 1. FIG. 1 is a side view of the plating apparatus 1, and the horizontal direction perpendicular to the plane of FIG. 1 is defined as the X direction, the horizontal direction orthogonal to this and along the plane of FIG. 1 is defined as the Y direction, and the vertical direction is defined as the Z direction. Also, in each figure, the dotted arrows represent the moving directions of the respective members.

[0019] The plating apparatus 1 has a configuration in which each of the parts described later is assembled to a housing 10 formed by combining a plurality of frame members. In FIGS. 1 and the following figures, in order to avoid complication of the drawings, the description of some configurations may be appropriately omitted. Specifically, for configurations such as a holding mechanism for holding parts, a cover for covering parts, and a mechanism for attaching them to the housing 10, which have a relatively low contribution to the establishment of the invention and for which appropriate known techniques can be applied to their structures and no special explanation is required, the illustration may be omitted.

[0020] FIG. 1 is a front view of the plating apparatus 1. The plating apparatus 1 is provided with a transport unit 2 for transporting the substrate S along the Y direction. The transport unit 2 includes a plurality of transport rollers 21 arranged along the Y direction. Each transport roller 21 is rotatably supported with the X direction as the axial direction by a support mechanism (not shown). By rotating the transport roller 21 by a drive mechanism (not shown), the transport unit 2 transports the substrate S in the Y direction in a horizontal posture. The rectangular substrate S is transported with one of the four peripheral sides as the leading edge. Hereinafter, the transport path of the substrate S is represented by the symbol P, and the transport direction is represented by the symbol Dt.

[0021] The plating apparatus 1 further includes a loading unit 3, a plating processing unit 4, a rinsing processing unit 5, an unloading unit 6, a power supply unit 7, and a control unit 9. The loading unit 3, the plating processing unit 4, the rinsing processing unit 5, and the unloading unit 6 are arranged in this order along the transport direction Dt (Y direction) of the substrate by the transport unit 2. That is, in this plating apparatus 1, the substrate S is subjected to the necessary processing in each of the above processing units while being transported in the Y direction by the transport unit 2.

[0022] The loading unit 3 receives the unprocessed substrate S transported from the outside and temporarily holds it, and supplies the substrate S to the plating processing unit 4 at a necessary timing. The plating processing unit 4 is the main processing entity that executes the plating method according to the present invention, and performs a plating process by immersing the substrate S in a plating solution. Its configuration and operation will be described in detail later.

[0023] The rinsing processing unit 5 includes a rinsing tank 51, a vat 52, and a rinsing liquid supply / discharge unit 59. The rinsing tank 51 can store a rinsing liquid in an internal space having a size sufficient to accommodate the substrate S. An opening is provided in a portion of the side surface of the rinsing tank 51 in the Y direction that overlaps the conveyance path P, and shutters 51a and 51b are provided so as to be openable and closable with respect to the opening.

[0024] The vat 52 is disposed below the rinsing tank 51 and receives the rinsing liquid spilled from the rinsing tank 51. The rinsing liquid supply / discharge unit 59 supplies the rinsing liquid to the rinsing tank 51 and discharges the rinsing liquid from the rinsing tank 51 as necessary. The rinsing processing unit 5 performs a rinsing process on the substrate S immersed in the plating solution in the plating processing unit 4. For example, water is used as the rinsing liquid. The carry-out unit 6 temporarily holds the substrate S until the substrate S after the rinsing process is delivered to a post-treatment process by an external conveyance device.

[0025] The power supply unit 7 supplies necessary power to each part of the apparatus. The control unit 9 controls each part of the apparatus configured as described above and causes the plating apparatus 1 to perform a predetermined process. As the hardware configuration of the control unit 9, for example, the same as a general computer device can be used. That is, various processes described later can be realized by the CPU (FIG. 9) provided in the control unit 9 executing a control program prepared in advance. Although not particularly described below, each part of the apparatus operates based on a control command from the control unit 9.

[0026] The plating processing unit 4 includes a plating tank 41, baths 42 and 44, a chuck unit 40, a transfer mechanism 43, an anode electrode unit 45, a cleaning mechanism 48, and a plating solution supply / discharge unit 49. The plating tank 41 is capable of storing a plating solution in an internal space having a size sufficient to accommodate the substrate S. The bath 42 is disposed below the plating tank 41 and receives the spilled plating solution. The chuck unit 40 is disposed above the plating tank 41 and holds the substrate S to be subjected to plating processing. The bath 44 is disposed adjacent to the bath 42 below the plating tank 41 on the (-Y) side. The cleaning mechanism 48 cleans the chuck unit 40 with an appropriate cleaning liquid (for example, water). For this purpose, the cleaning mechanism 48 includes a cleaning nozzle 481 (FIG. 2) provided in the bath 44 and a cleaning liquid supply / discharge unit 482 that supplies the cleaning liquid to the cleaning nozzle 481. The plating solution supply / discharge unit 49 supplies the plating solution to the plating tank 41 and discharges the plating solution from the plating tank 41 as necessary.

[0027] FIGS. 2 and 3 are diagrams showing a schematic configuration of the plating processing unit. More specifically, FIG. 2 is a diagram corresponding to a front view of the main part of the plating processing unit 4 viewed in the (-X) direction, and FIGS. 3(a) and 3(b) are diagrams corresponding to side views of the plating processing unit 4 viewed in the (+Y) direction. In order to avoid making the drawings complicated, the illustration of the anode electrode unit 45 is omitted in FIGS. 2 and 3(a).

[0028] As shown in FIGS. 1 and 2, openings are provided in portions of the (-Y) side surface and the (+Y) side surface of the plating tank 41 that overlap the transfer path P, and shutter 41a and 41b that can be opened and closed are respectively provided in the openings. In the open state of the shutters 41a and 41b, the substrate S conveyed along the transfer path P by the transfer unit 2 can pass through the openings provided in the side surface of the plating tank 41. Thereby, it becomes possible to carry in the unprocessed substrate S into the plating tank 41 and carry out the processed substrate S from the plating tank 41.

[0029] On one hand, in the closed state, the opening provided on the side surface of the plating tank 41 is blocked. At this time, the conveyance path P of the substrate S is blocked, but inside the plating tank 41, it is possible to store the plating solution exceeding the height of the opening. After the substrate S is accommodated in the plating tank 41 with the shutter 41a on the (-Y) side in the open state, the shutter 41a is closed, and the internal space of the plating tank 41 is filled with the plating solution L, whereby the substrate S is immersed in the plating solution L and plated. Then, when the plating solution is discharged and the shutter 41b on the (+Y) side is opened, the liquid level of the plating solution L drops below the lower end of the opening, and the substrate S after the plating process is carried out to the rinsing section 5. Regarding the operations of the shutters 41a and 41b, they may open and close independently of each other or may open and close integrally.

[0030] As shown in Fig. 3(a), a rotation motor 23 is coupled to the rotation shaft 22 of the conveyance roller 21. In response to a control command from the control unit 9, the rotation motor 23 rotates, thereby rotating the conveyance roller 21, and thereby the substrate S is conveyed in the Y direction. Note that some of the rollers may be driven rollers to which a drive source is not connected.

[0031] Also, as shown in Fig. 3(a), two sets of chuck portions 40 are arranged corresponding to both ends of the substrate S accommodated in the plating tank 41 in the X direction. In Figs. 1 and 2, only one set on the (+X) side among them is shown. The two sets of chuck portions 40 are arranged symmetrically with respect to the YZ plane, but the basic structures are the same. That is, each chuck portion 40 includes at least one chuck mechanism 400, a support frame 430 that supports the chuck mechanism 400, and a moving mechanism 43 that moves the support frame 430 in the Y direction.

[0032] The support frame 430 is supported so as to be movable in the Y direction by a moving mechanism 43 attached to the upper frame 11 among the frame members constituting the housing 10. More specifically, the moving mechanism 43 includes a guide rail 431 fixed to the upper frame 11 above the plating treatment unit 4 and extending in the Y direction, a slider 432 engaged with the guide rail 431, and a drive source (not shown) that moves the slider 432 in the Y direction along the guide rail 431. As these configurations, an appropriate linear motion mechanism, for example, a linear motor, a linear guide mechanism, a chain drive mechanism, or a belt drive mechanism, etc. can be applied. For example, a single-axis robot in which such a drive mechanism is integrated in advance can be preferably applied.

[0033] The support frame 430 is coupled to the lower end of the slider 432, and the chuck mechanism 400 is fixed to the support frame 430. Therefore, when the slider 432 moves in the Y direction along the guide rail 431, the support frame 430 and the chuck mechanism 400 attached thereto move integrally in the Y direction. That is, by operating the moving mechanism 43 according to a control command from the control unit 9 to run the slider 432, the chuck mechanism 400 moves in the Y direction.

[0034] In this embodiment, three sets of chuck mechanisms 400 are arranged side by side in the Y direction with respect to one support frame 430, and these move integrally in the Y direction as the support frame 430 moves. Thereby, each chuck mechanism 400 can reciprocate in the Y direction between a "plating position" P1 located above the plating tank 41 and a "washing position" P2 located above the vat 44. In FIG. 2, the chuck mechanism 400 when at the plating position P1 is shown by a solid line, and the chuck mechanism 400 when at the washing position P2 is shown by a dotted line. On the other hand, in FIG. 1, the chuck mechanism 400 at the washing position P2 is shown by a solid line.

[0035] The chuck mechanism 400 grips the substrate S and stably maintains the posture of the substrate S in the plating bath 41, and electrically contacts the built-in cathode electrode with one main surface of the substrate S. Then, by applying a DC voltage between the anode electrode and the cathode electrode described later, a film is formed on the one main surface by electrolytic plating. Here, it is assumed that a film is formed on the upper surface of the substrate S.

[0036] The chuck mechanism 400 grips the substrate S at both end portions in the X direction of the substrate S, that is, at both end portions in the width direction orthogonal to the conveyance direction Dt. Then, by a plurality of chuck mechanisms 400 provided along the Y direction, that is, along the conveyance direction Dt of the substrate S, most of the substrate S is gripped at both end portions in the X direction. The chuck mechanism 400 not only helps to stably maintain the posture of the substrate S by gripping the substrate S, but also can apply a uniform potential over a wide range by bringing the cathode electrode 412 extending in the Y direction into contact with the substrate S. Therefore, this plating apparatus 1 can form a plating film with good uniformity on the substrate S.

[0037] FIG. 4 is a diagram showing a schematic configuration of the chuck mechanism. More specifically, FIG. 4(a) is a perspective view schematically showing the structure of the chuck mechanism 400, and FIG. 4(b) is a diagram showing the gripping state of the substrate S by the chuck mechanism 400. In the following description of the structure and operation of the chuck mechanism 400, the chuck mechanism 400 that mainly holds the (-X) side end portion of the substrate S is exemplified for explanation. However, by considering the same structure inverted around the Z axis, the structure and operation of the chuck mechanism that holds the (+X) side end portion of the substrate S can be understood. Also, in order to enhance the visibility of the figure, some illustrations of the configuration of the chuck mechanism 400 are omitted in FIG. 4(a).

[0038] The chuck mechanism 400 grips the X-direction end of the substrate S with an upper chuck 411 and a lower chuck 421 that can be raised and lowered independently of each other. Specifically, the upper chuck 411 and the lower chuck 421 are each a long and thin flat member extending with the Y direction as the longitudinal direction, and grip the substrate S by a bottom surface 411b of the upper chuck 411 abutting against the (-X) side end of the upper surface Sa of the substrate S and an top surface 421a of the lower chuck 421 abutting against the (-X) side end of the lower surface Sb of the substrate S. In practice, a cathode electrode 412 is attached to the bottom surface 411b of the upper chuck 411, and the cathode electrode 412 comes into contact with the upper surface Sa of the substrate S.

[0039] The cathode electrode 412 is electrically connected to the power supply unit 7. In addition, a sealing member 415 formed in a ring shape from an elastic material is provided so as to surround the periphery of the cathode electrode 412. When the upper chuck 411 is separated from the substrate S, the lower end of the sealing member 415 extends below the lower surface of the cathode electrode 412.

[0040] 4(b), when the cathode electrode 412 comes into contact with the upper surface Sa of the substrate S, the seal member 415 elastically deforms to surround the cathode electrode 412 in an airtight state. Therefore, even when the substrate S is immersed in the plating solution, the cathode electrode 412 is maintained in a dry state without coming into contact with the plating solution. This makes it possible to prevent corrosion of the cathode electrode 412 or formation of a coating due to contact with the plating solution.

[0041] 4(b), the lower chuck 421 abuts against the lower surface Sb of the substrate S from below, thereby acting to determine the position of the substrate S in the height direction (Z direction). The lower chuck 421 also acts as a backup when the cathode electrode 412 provided on the upper chuck 411 is brought into contact with the substrate S. This ensures that the height position of the substrate S is stably maintained, and also ensures reliable electrical contact between the cathode electrode 412 and the substrate upper surface Sa.

[0042] On the upper surface 411a of the upper chuck 411, a shaft member 413 extending in the Z direction is attached, and the shaft member 413 is supported by a lifting mechanism 414 so as to be movable up and down. The upper chuck 411 is fixed to the shaft member 413 using, for example, a screw and is detachable (i.e., replaceable). The lifting mechanism 414 has an appropriate linear motion mechanism such as a solenoid, a linear motor, or a ball screw mechanism, and raises and lowers the shaft member 413. Thereby, the upper chuck 411 attached to the lower end of the shaft member 413 moves up and down. Here, a unit integrally configured including the upper chuck 411, the shaft member 413, the lifting mechanism 414, etc. is referred to as the "upper chuck unit 410".

[0043] Similarly, on the upper surface 421a of the lower chuck 421, a shaft member 423 extending in the Z direction is attached, and the shaft member 423 is supported by a lifting mechanism 424 so as to be movable up and down. The lower chuck 421 is fixed to the shaft member 423 using, for example, a screw and is detachable. The lifting mechanism 424 has an appropriate linear motion mechanism such as a solenoid, a linear motor, or a ball screw mechanism, and raises and lowers the shaft member 423. Thereby, the lower chuck 421 attached to the lower end of the shaft member 423 moves up and down. Here, a unit integrally configured including the lower chuck 421, the shaft member 423, the lifting mechanism 424, etc. is referred to as the "lower chuck unit 420".

[0044] The upper chuck unit 410 is fixed to the support member 401. Therefore, the upper chuck 411 can only move up and down with respect to the support member 401. On the other hand, the lower chuck unit 420 is attached to the support member 401 via a reciprocating mechanism 402. Specifically, a support member 403 to which the lower chuck unit 420 is attached is coupled to the movable part of the reciprocating mechanism 402 having the X direction as the movable direction. The reciprocating mechanism 402 has an appropriate linear motion mechanism such as a solenoid, an air cylinder, a linear motor, or a ball screw mechanism, and its main body is fixed to the support member 401.

[0045] Therefore, due to the operation of the reciprocating mechanism 402, the lower chuck unit 420 can move in the X direction within the movable range defined by a stopper (not shown). Accordingly, the lower chuck 421 can move up and down with respect to the support member 401 by the operation of the lifting mechanism 424, and can move forward and backward in the X direction by the reciprocating mechanism 402 moving the lifting mechanism 424.

[0046] When the lower chuck 421 extends to the most (+X) side within the movable range, as shown by the solid line in Fig. 4(b), the (+X)-side tip of the lower chuck 421 is located on the (+X) side of the end face of the substrate S, and the upper surface 421a of the lower chuck 421 can support the lower surface Sb of the substrate S. On the other hand, as shown by the dotted line in Fig. 4(b), when the lower chuck 421 retracts to the most (-X) side within the movable range, the (+X)-side tip of the lower chuck 421 has retreated to the (-X) side of the end face of the substrate S. For this reason, contact between the lower chuck 421 and the substrate S when the lower chuck 421 moves up and down is avoided.

[0047] In the chuck mechanism 400, the upper chuck 411 and the lower chuck 421 cooperate to grip the substrate S in the plating bath 41. Specifically, the upper chuck 411 and the lower chuck 421 descend from the chuck mechanism 400 positioned at the plating position to the inside of the plating bath 41, and grip the end of the substrate S at the same height as the height of the substrate S supported by the transfer roller 21. For this reason, the substrate S is held in a horizontal posture with a flat upper surface in the plating bath 41. The Z-direction positions of the upper chuck 411 and the lower chuck 421 at this time are hereinafter referred to as the "lower position".

[0048] As shown in Figs. 1 and 3(b), above the transfer path P in the plating bath 41, an anode electrode unit 45 is arranged. The anode electrode unit 45 is divided into a plurality of plate-like members, and includes a plurality of anode electrodes 451 each electrically connected to the power supply unit 7. Further, the anode electrode 451 is housed in a box-shaped isolation tank 450 with an open upper part.

[0049] FIG. 5 is a diagram schematically showing the configuration of the main part of the anode electrode unit. The anode electrode 451 has a plurality of electrode plates arranged in the horizontal direction. In the example shown in FIG. 5(a), nine electrode plates 451a to 451i arranged in a 3×3 matrix constitute the anode electrode 451. The lower surfaces of the respective electrode plates 451a to 451i facing the substrate S are in the same horizontal plane as each other.

[0050] The anode electrode 451 is electrically connected to the power supply unit 7 and receives supply of electrical energy. More specifically, the power supply unit 7 has a plurality of output units 71a to 71i capable of setting output currents independently of each other, and the output unit 71a is connected to the electrode plate 451a, and the main power unit 71b is connected to the electrode plate 451b. In this way, the plurality of electrode plates and the plurality of output units are electrically connected one-to-one. Each of the output units 71a to 71i can be constituted by, for example, a DC constant current source, or a DC or pulsating current voltage source capable of setting an upper limit of the output current.

[0051] The output currents of the respective output units 71a to 71i are determined according to control commands from the control unit 9. Specifically, the power supply unit 7 is provided with a setting storage unit 72, and the setting storage unit 72 stores information regarding the current values that the respective output units 71a to 71i should output. Each of the output units 71a to 71i outputs a current having a predetermined current value based on the information stored in the setting storage unit 72. The current values of the respective output units 71a to 71i stored and saved in the setting storage unit 72 can be changed and set by control commands from the control unit 9 or by user operation inputs.

[0052] The isolation tank 450 includes a frame body 452 that laterally surrounds the anode electrode 451, and an electrolytic diaphragm 453 that closes the lower part of the frame body 452 to form the bottom of the isolation tank 450. The frame body 452 has a substantially rectangular shape in plan view and penetrates in the vertical direction, and is formed of a material having corrosion resistance against the plating solution L, for example, a resin material. Further, the electrolytic diaphragm 453 is formed in a flat plate shape or a sheet shape of a material that blocks non-ionized substances while allowing metal ions to pass through. For example, the electrolytic diaphragm 453 can be constituted by a porous resin material, an ion exchange resin material, or the like.

[0053] By the electrolytic diaphragm 453 closing the lower part of the frame body 452 to form the bottom surface, a rectangular box-shaped isolation tank 450 with an open upper part is constituted. The anode electrode 451 is accommodated in the internal space 454 of this isolation tank 450 as shown by the dashed-dotted arrow. To enable this, the inner wall of the frame body 452 constituting the isolation tank 450 has a rectangular shape that is slightly larger than the outer dimension of the anode electrode 451 in plan view. Further, considering the convenience of the replacement work due to the consumption of the electrode material, the anode electrode 451 is preferably detachable from the isolation tank 450.

[0054] As will be described next, the isolation tank 450 containing the anode electrode 451 is immersed in the plating solution L stored in the plating tank 41.

[0055] FIG. 6 is a diagram schematically showing a state in which the isolation tank is immersed in the plating tank. As shown in FIG. 6(a), in the isolation tank 450, at least the lower surface of the electrolytic diaphragm 453 forming the bottom surface thereof is arranged to be in contact with the plating solution L stored in the plating tank 41. Further, in the internal space 454 of the isolation tank 450, a second plating solution L2 is injected to such an extent that the anode electrode 451 is immersed in the solution. The composition of the second plating solution L2 is not particularly limited, and for example, it can be the same as the plating solution L stored in the plating tank 41. Here, the "same composition" refers to that at the time of supply, and differences may occur in the composition as the treatment progresses. Also, for example, although it is substantially the same in that the type of the main component is the same as that of the first plating solution, its concentration may be different, or at least one of the presence or absence, type, and content of the additive may be partially different. Depending on the purpose, it is also possible to use a liquid having a composition different from that of the first plating solution as the second plating solution.

[0056] Therefore, inside the plating tank 41, the substrate S supported by the chuck mechanism 400 (upper chuck 411, lower chuck 421) and the anode electrode 451 are arranged to face each other via the plating solution L (+L2) and the electrolytic diaphragm 453.

[0057] A predetermined gap G1 greater than zero is provided between the lower surface of the anode electrode 451 and the upper surface of the electrolytic diaphragm 453. Also, a predetermined gap G2 greater than zero is provided between the lower surface of the electrolytic diaphragm 453 and the upper surface of the substrate S. Therefore, the gap G between the lower surface of the anode electrode 451 and the upper surface of the substrate S is expressed by the following formula using the thickness t of the electrolytic diaphragm 453: G = G1 + G2 + t as represented by.

[0058] As shown in FIGS. 5 and 6(b), one output terminal of each of the output portions 71a to 71i is individually connected to each of the electrode plates 451a to 451i, while the other output terminals are collectively connected to the cathode electrode 412. Then, as shown in FIG. 4(b), a cathode electrode 412 is provided at the lower end of the upper chuck 411 and is in contact with the upper surface of the substrate S.

[0059] Therefore, when output currents of a predetermined magnitude are respectively output from each of the output units 71a to 71i of the power supply unit 7, a current flows from the anode electrode 451 through the electrolytic diaphragm 453 toward the upper surface of the substrate S as indicated by the arrow in FIG. 6(b). The electrochemical reaction caused by the action of this current forms a plating film on the upper surface of the substrate S.

[0060] In this electrochemical reaction, the non-uniformity of the current density distribution on the upper surface of the substrate S affects the quality of the plating film. That is, in order to obtain a film with uniform composition and thickness, it is desirable to obtain a uniform current density distribution within the plane of the substrate S. However, due to the fact that the substrate S is made of glass, which is an insulator, its outer shape is rectangular, and the electrical contact with the cathode electrode 412 is limited to the peripheral portion of the substrate S, it is not easy to keep the current density uniform. In the electrolytic plating technique in which an anode electrode is opposed to one main surface of the substrate and a cathode electrode is brought into contact with the peripheral portion of the substrate as in the present embodiment, current concentration easily occurs at the peripheral portion of the substrate. For this reason, there is a tendency for the film thickness at the peripheral portion to become larger than that at the central portion. In particular, when attempting to shorten the tact time of the plating process, it is necessary to increase the amount of current supplied from the power supply unit 7, but this also increases the current bias.

[0061] As a countermeasure against this problem, for example, there is a technique of attempting to alleviate current concentration by covering the peripheral portion of the substrate with a shielding plate. However, for a large substrate such as a glass substrate for a display device, a large shielding plate is also required to cover its periphery, and moreover, it is necessary to optimize the size of the shielding plate according to the substrate size, which leads to an increase in the device cost. Also, regarding the size and shape of an effective shielding plate for a rectangular substrate, there has not been sufficient knowledge so far.

[0062] In this embodiment, the anode electrode 451 is divided into a plurality of electrode plates 451a to 451i. And for each of the electrode plates 451a to 451i, output parts 71a to 71i capable of independently setting the output current are individually connected. For this reason, by individually adjusting the amount of current supplied to each of the electrode plates 451a to 451i, it is possible to change the density distribution of the current flowing from the anode electrode 451 toward the substrate S. Thereby, by correcting the current bias and making the current density approach a uniform distribution, it becomes possible to improve the uniformity of the plating film.

[0063] As described above, in a rectangular substrate, current concentration is likely to occur at the peripheral portion. In view of this, it can be said that among the electrode plates 451a to 451i, the amount of current in the electrode plate 451e facing the central portion of the substrate S is small, and the amount of current in the other electrode plates arranged so as to surround this in the horizontal direction tends to be larger. Therefore, it is expected that by setting the amount of current to the electrode plate 451e arranged in the center to be larger than that of the other electrode plates, the current distribution can be made closer to a uniform one.

[0064] Also, from the holding mode in which the cathode electrodes 412 contact both ends in the X direction of the substrate S, it is predicted that the current tends to be larger at the ends in the X direction than at the ends in the Y direction. From this, it can be said that for the electrode plates 451b and 451h located at both ends in the Y direction in the arrangement of the electrode plates, it is desirable to apply a larger current than the electrode plates 451d and 451f located at both ends in the X direction.

[0065] Thus, it is possible to predetermine the current input to each of the electrode plates 451a to 451i based on the shape of the substrate S and the electrode arrangement. In order to more accurately achieve uniform current density, the current distribution can be measured by a preliminary experiment, and the set value of the current supplied to each of the electrode plates 451a to 451i can be determined for each of the output parts 71a to 71i so as to correct the bias of the current distribution from the result.

[0066] For the purpose of equalizing the current density near the substrate surface, for example, the current set value can be optimized as follows. Here, the value obtained by dividing the current value applied to each electrode plate by the area of the lower surface (the surface facing the substrate S) of the electrode plate (hereinafter referred to as the "electrode area") is defined as the "electrode current density". And if it is considered that this electrode current density represents the current density at the portion of the upper surface Sa of the substrate facing the electrode plate, the output current values to each of the electrode plates 451a to 451i may be determined so that the electrode current density becomes the appropriate current density at each position on the substrate S. In this way, when the electrode areas of the electrode plates 451a to 451i are equal or different, it is possible to appropriately set the output current values for the electrode plates 451a to 451i.

[0067] For example, as in the above-described case, when the current density tends to be high at the peripheral portion of the substrate S and low at the central portion, by setting the electrode current density to be large in the electrode plate 451e arranged at the central portion and small in the other electrode plates arranged around it, it is possible to equalize the overall current density distribution. For those electrode plates in which a part of the lower surface is located outside the substrate S in plan view and there is a portion not facing the substrate S, the area of the portion facing the substrate S may be considered as the effective electrode area. Also, if the peripheral portion of the electrode plate does not protrude significantly outside the substrate S, in fact, the current output from the portion hitting outside the substrate S can also reach the substrate S and contribute to the plating reaction. In this case, the entire electrode plate may be regarded as an effective electrode and included in the electrode area.

[0068] Regarding the determined set value, it can be stored in advance as a preset value in the setting storage unit 72 of the power supply unit 7, and this can be read out to operate each of the output units 71a to 71i. The user and the control unit 9 can change this setting as necessary. Thereby, it is possible to cope even when it is necessary to change the current distribution, for example, when changing the size of the substrate S.

[0069] Regarding the isolation tank 450, it is also conceivable to configure it with a material having ion permeability not only for the bottom surface but also for the side wall surfaces. However, the movement of ions through the side wall surfaces causes current concentration at the peripheral portion of the substrate, impairing the uniformity of the plating film. By allowing only ion movement through the bottom surface of the isolation tank facing the upper surface of the substrate S, such current concentration can be prevented.

[0070] For the same reason, if the cathode electrode 412 is disposed directly below the electrolytic diaphragm 453 forming the bottom of the isolation tank 450, a shorter current path is formed in that portion, resulting in current concentration. To avoid this, in a plan view, the cathode electrode 412 preferably contacts the substrate S outside the region of the upper surface Sa of the substrate facing the anode electrode 451, more preferably outside the bottom of the isolation tank 450.

[0071] In that sense, it is also effective to configure the frame 452 with a material having no ion permeability and to make the outer dimension of the isolation tank 450 in a plan view (more precisely, the outer dimension of the electrolytic diaphragm 453 forming the bottom) smaller than the outer dimension of the substrate S. With these configurations, since the movement of ions through paths other than the electrolytic diaphragm 453 is prevented, it can be said that the isolation tank itself functions in the same way as the blocking plate in the prior art. As shown in FIG. 6(b), these conditions are satisfied in the present embodiment.

[0072] In the electroplating process thus performed, it is possible to form a plating film of a metal on the surface of the substrate S by using, for the anode electrode 451, a metal soluble in the plating solution L which is the electrolyte solution. For example, for the purpose of forming a copper plating film on the substrate S which is a glass substrate, an aqueous solution of copper sulfate can be preferably applied as the plating solution L (L2), and a copper plate can be preferably applied as the anode electrode 451.

[0073] A DC voltage is applied between the anode electrode 451 and the cathode electrode 412, and current is supplied to the anode electrode 451. As a result, the metal material (e.g., copper) is ionized from the anode electrode 451 and dissolved into the plating solution L2. The ionized metal passes through the electrolytic diaphragm 453 and the plating solution L and adheres to the upper surface of the substrate S to form a plating film. That is, the anode electrode 451 in this plating reaction is a so-called soluble electrode that contains the material consumed for the formation of the plating film.

[0074] In this process, the anode electrode 451 gradually dissolves into the plating solution L (L2), and at this time, the insoluble impurities contained in the electrode material are released from the anode electrode 451 into the solution. The insoluble residue thus generated in the plating solution is sometimes called "anode slime" or "anode mud".

[0075] In the present embodiment, a structure is adopted in which the substrate S is supported in a horizontal posture with the surface to be plated facing upward, and the anode electrode 451 is disposed above it. Therefore, the anode slime composed of impurities released from the anode electrode 451 settles in the plating solution toward the substrate S disposed below. When such impurities adhere to the upper surface of the substrate S, which is the surface to be plated, it causes plating defects and deteriorates the quality of the plating film.

[0076] To address this problem, in the present embodiment, the anode electrode 451 and the substrate S are isolated by the isolation layer 450. Specifically, an electrolytic diaphragm 453 is disposed between the lower surface of the anode electrode 451 and the upper surface of the substrate S, and the side of the anode electrode 451 is surrounded by a frame body 452. Then, the isolation tank 450 is immersed in the plating solution L in the plating tank 41, and its internal space 454 is filled with the plating solution L2 having the same composition as the plating solution L.

[0077] Therefore, for the metal ions involved in the plating reaction, a path from the anode electrode 451 to the substrate S through the plating solutions L, L2 and the electrolytic diaphragm 453 is ensured. On the other hand, for the liquid components and insoluble components in the plating solution, the anode electrode 451 and the substrate S are isolated from each other by the isolation tank 450. For this reason, the anodic slime formed by the aggregation of insoluble components is blocked by the electrolytic diaphragm 453 and does not adhere to the substrate S.

[0078] Also, since the upper part of the box-shaped isolation tank 450 is open, the upper part of the anode electrode 451 accommodated in the isolation tank 450 is in an open state. Therefore, it is possible to easily perform the attachment / detachment operation of the anode electrode 451 with respect to the isolation tank 450. As the reaction progresses, the anode electrode 451 is consumed, so periodic replacement is necessary. The above structure also contributes to improving the convenience in such replacement operations.

[0079] And the anode electrode 451 is divided into a plurality of electrode plates 451a to 451i. Therefore, the replacement operation can be performed for each electrode plate. This improves the workability in replacement and also leads to effective utilization of resources because only the electrode plates that are necessary among the anode electrodes 451 can be replaced.

[0080] Regarding the intervals between the electrode plates 451a to 451i in the horizontal direction, for example, they can be made smaller than the distance between the lower surfaces of the electrode plates 451a to 451i and the substrate S, and more preferably, they can be set to be half or less of the said distance. If the intervals between the electrode plates become large, there is a possibility that sufficient current is not supplied in the region of the upper surface Sa of the substrate that does not face any of the electrode plates, resulting in uneven current density. It is known that the current flowing out from the electrode plate spreads to some extent from the outer edge of the electrode plate in the liquid. According to the findings of the inventor of the present application regarding this, it is possible to suppress such current unevenness by setting the intervals as described above.

[0081] Next, a mechanism for supporting the isolation tank 450 in the anode electrode unit 45 will be described. Due to the structural constraint that the bottom surface of the isolation tank 450 is arranged to face the substrate S and the isolation tank 450 is immersed in the plating solution L stored in the plating tank 41, the support mechanism for the isolation tank 450 needs to be provided above the isolation tank 450. Also, in order to refresh the plating solution L2 and suppress the deposition of anode slime on the electrolytic diaphragm 453, it is desirable to periodically replace the plating solution L2 stored in the isolation tank 450. The support mechanism described below meets such requirements.

[0082] FIG. 7 is an external perspective view showing a support mechanism for an isolation tank in the anode electrode unit. In FIG. 7, for the purpose of clearly showing the structure of the support mechanism, the description of the anode electrode 451 accommodated in the internal space 454 of the isolation tank 450 is omitted. In the anode electrode unit 45, the isolation tank 450 is attached to the housing 10 via the support mechanism 460. The support mechanism 460 supports the isolation tank 450 so as to be movable up and down with respect to the plating tank 41 fixed to the frame 10.

[0083] The support mechanism 460 includes support frames 461, 462, 463 arranged in the vertical direction (Z direction). These support frames have the relationship that the first support frame 461 arranged at the lowermost side supports the isolation tank 450, the second support frame 462 arranged above it supports the first support frame 461, the third support frame 463 arranged further above it supports the second support frame 462, and the third support frame 463 is fixed to the upper frame 11 (FIGS. 1 and 3(a)) of the housing 10.

[0084] Each of the support frames 461 to 463 has a generally rectangular outer shape and has a frame-like structure with a central portion penetrating vertically. Among these, four sets of lifting guide mechanisms 466 with the vertical direction as the operating direction are attached to the uppermost third support frame 463. Specifically, linear bushes 466a of the lifting guide mechanism 466 are provided at the four corners of the support frame 463. The linear bush 466a is a hollow cylindrical member penetrating vertically, and a movable rod 466b is inserted into the hollow portion. The movable rod 466b extends downward from the linear bush 466a, and its lower end is coupled to the second support frame 462 below.

[0085] When the lifting mechanism 47 described later operates in response to a control command from the control unit 9, the movable rod 466b moves up and down within a predetermined movable range, whereby the second support frame 462 coupled to the lower end of the movable rod 466b moves up and down. At this time, the first support frame 461 supported by the second support frame 462 and the isolation tank 450 supported by the first support frame 461 also move up and down in the same manner.

[0086] Similarly, four sets of lifting guide mechanisms 465 with the vertical direction as the operating direction are attached to the second support frame 462. Specifically, bushes 465a of the lifting guide mechanism 465 are provided at the four corners of the support frame 462, and a movable rod 465b is inserted into the linear bush 465a. The movable rod 465b extends downward from the linear bush 465a, and its lower end is coupled to the first support frame 461 below.

[0087] When the lifting mechanism 47 operates in response to a control command from the control unit 9, the movable rod 465b moves up and down within a predetermined movable range, whereby the first support frame 461 coupled to the lower end of the movable rod 465b moves up and down. At this time, the isolation tank 450 supported by the first support frame 461 also moves up and down in the same manner.

[0088] In this way, the lifting guide mechanisms 465 and 466 can cooperate with the lifting mechanism 47 to move the isolation tank 450 in the vertical direction. As the lifting guide mechanisms 465 and 466, various mechanisms can be applied in addition to the combination of the cylindrical linear bush and the movable rod described above. For example, various mechanisms capable of restricting the movement of an object in one direction, such as a linear motion guide mechanism combining a guide rail and a slider, can be used. Note that the lifting guide mechanisms 465 and 466 may be provided with a damper function, similar to the lifting guide mechanism 464 described below.

[0089] On the other hand, the first support frame 461 supports the isolation tank 450 so as to be vertically movable and tiltable about the X-axis. Specifically, four sets of lifting guide mechanisms 464 are attached to the first support frame 461, and a movable rod 464b extends downward from the linear bush 464a of the lifting guide mechanism 464. As will be described later, the lifting guide mechanism 464 has a damper mechanism, thereby reducing the impact transmitted to the isolation tank 450 when the isolation tank 450 is lifted or lowered.

[0090] Further, a frame 455 formed by combining a plate material 455a extending in the X direction and a plate material 455b extending in the Y direction is attached to the upper part of the frame body 452 constituting the isolation tank 450, and hinge members 455c are attached to four locations on the upper part of the frame 455. The lower ends of the movable rods 464b extending from the four lifting guide mechanisms 464 are respectively engaged with the hinge members 455c located directly below, and are rotatably attached about an axis parallel to the X-axis. In this way, the isolation tank 450 is supported by the support frame 461 via the support mechanism 460.

[0091] In addition, a roller member 455f rotatably supported by an appropriate support member is provided between the two hinge members 455c and 455c arranged on the (-Y) side among the four hinge members 455c. The roller member 455f is not connected to the drive mechanism and can rotate freely. The function of the roller member 455f will be described later.

[0092] Also, around the isolation tank 450, equipment for supplying and discharging the plating solution L2 to and from the isolation tank 450 is arranged. That is, above the isolation tank 450, a nozzle 491 for discharging the plating solution sent from the plating solution supply / discharge unit 49 toward the internal space 454 of the isolation tank 450 is provided. The nozzle 491 is attached to the frame 455 via an appropriate fixing member.

[0093] The plating solution supply / discharge unit 49 and the nozzle 491 are connected by a pipe 492 to form a supply path for the plating solution. A flexible joint 493 is provided at a position close to the isolation tank 450 in the pipe 492. The flexible joint is a pipe member in which at least a part of the pipe is formed of a flexible material such as rubber, and by being inserted into a part of a piping system mainly composed of non-flexible pipe materials, the bending of the pipe is allowed at the insertion location. For example, for the purpose of absorbing mutual displacement and vibration at the connection location between pipes, flexible joints are widely used.

[0094] As will be described later, in order to efficiently discharge the plating solution, the isolation tank 450 is provided so as to be rotatable about the X axis. By inserting the flexible joint 493 into the pipe 492, a supply path for the plating solution can be formed between the plating solution supply / discharge unit 49 and the nozzle 491 while allowing such rotation.

[0095] Also, the isolation tank 450 is provided with a pipe for discharging the plating solution stored in the internal space 454 to the plating solution supply / discharge unit 49. Specifically, in the frame body 452 constituting the isolation tank 450, a through hole 452a is provided at the lower part of the side surface on the (+Y) side, and a discharge pipe 494 is connected here. Similar to the plating solution supply pipe 492, a flexible joint 495 is also inserted into the discharge pipe 494.

[0096] Furthermore, above the anode electrode unit 45, a lifting mechanism 47 fixed to the frame 11 of the housing 10 is provided. Here, for the purpose of principle explanation, it is assumed that the lifting mechanism 47 is a winch mechanism that raises and lowers an object by winding a wire. That is, a wire 471 is vertically suspended from the lifting mechanism 47, and the wire 471 reaches a position directly above the isolation tank 450 through the openings at the central portions of the support frames 461 to 463. The lower end of the wire 471 is attached to a latching portion 455d provided on the frame 455. The latching portion 455d provided on the frame 455 is disposed at a position closer to the (-Y) side than the intermediate position between the two hinge members 455c and 455c arranged in the Y direction.

[0097] The lifting mechanism 47 operates in response to a control command from the control unit 9, and moves the isolation tank 450 in the vertical direction integrally with the frame 455 latched to the wire 471. Such vertical movement of the isolation tank 450 can be realized by using mechanisms of various drive methods other than the above. For example, known ball screw mechanisms, air cylinder mechanisms, linear motion mechanisms such as linear motor mechanisms, and those commercialized as a dip chain actuator (registered trademark) can be preferably applied.

[0098] FIG. 8 is a diagram schematically showing the state of supply and discharge of the plating solution to the isolation tank. Although simplified in FIG. 7, as shown in FIG. 8(a), the lifting guide mechanism 464 includes a linear bush (also referred to as a linear bearing, linear bearing, etc.) 464a through which a movable rod 464b extending in the vertical direction (Z direction) is inserted, a base member 464c to which the linear bush 464a is attached, a plate-shaped bracket 464d attached to the upper end of the movable rod 464b, and a damper mechanism 464e provided between the plate member 464d and the base member 464c. As the damper mechanism 464e, for example, a known shock absorber can be applied.

[0099] The movable rod 464b is inserted into the linear bush 464a so as to be vertically movable relative thereto. When the movable rod 464b moves up and down, the bracket 464d moves up and down accordingly. When the bracket 464d descends and abuts against the damper mechanism 464e, further downward displacement is restricted. That is, the damper mechanism 464e has a function of defining the movable range while allowing the movable rod 464b to move up and down and reducing the impact at the time of the descent stop.

[0100] In the Y direction, two sets of lifting guide mechanisms 464 are provided at different positions. Further, the lower end of the movable rod 464b of each lifting guide mechanism 464 is engaged with a hinge member 455c attached to the frame 455 of the isolation tank 450. Thereby, in the steady state, the isolation tank 450 is supported in a substantially horizontal posture.

[0101] In the state where the isolation tank 450 is supported in a substantially horizontal posture in this way, as shown by the white arrow in Fig. 8(a), the plating solution L2 is supplied to the isolation tank 450 from the plating solution supply and discharge section 49 through the pipe 491. The plating solution L2 is discharged from the discharge port provided on the lower surface of the nozzle 491 toward the internal space 454 of the isolation tank 450, and thus the plating solution L2 is supplied to the isolation tank 450. The plating process is executed in a state where the anode electrode 451 is immersed in the plating solution L2.

[0102] After the completion of the plating process, the plating solution L2 in the internal space 454 can be refreshed by discharging the existing plating solution and replenishing with a new plating solution. However, when discharging the plating solution L2 from the isolation tank 450, a discharge path cannot be provided below the isolation tank 450. This is because the substrate S is arranged directly below the isolation tank 450.

[0103] In addition, it is also conceivable to flow the plating solution L2 from the separation tank 450 to the plating tank 41 and discharge the plating solution L2 through the plating tank 41. However, if this is done, the anodic slime contained in the plating solution L2 will mix into the plating tank 41. Therefore, it is preferable to discharge the plating solution L2 through a path independent of the discharge from the plating tank 41.

[0104] For the same reason, in the supply of the plating solution to the separation tank 450 and the process of tilting the separation tank 450 described later to promote drainage, it is necessary to avoid the plating solution L2 overflowing from the separation tank 450 and flowing into the plating tank 41.

[0105] In order to drain the liquid while satisfying these requirements, a discharge port is provided on the side wall surface of the separation tank 450 to discharge the plating solution laterally. However, compared with the case where a discharge port is provided on the bottom surface, it is inevitable that the smoothness of the discharge will be impaired. Therefore, in this embodiment, a through hole 452a as a discharge port is provided on the (+Y) side side surface of the separation tank 450, and a discharge pipe 494 is connected. When discharging the plating solution L2, the separation tank 450 is lifted on the side opposite to the discharge port, that is, the (-Y) side, to incline the bottom surface. By doing so, the discharge of the plating solution L2 from the internal space 454 can be promoted.

[0106] Specifically, when the lifting mechanism 47 winds up the wire 471, as shown by the dashed arrow in Fig. 8(b), the frame 455 can be lifted to lift the (-Y) side end of the separation tank 450. In this way, when the separation tank 450 is in an inclined posture with its bottom surface inclined with respect to the horizontal plane, as shown by the white arrow in Fig. 8(b), the plating solution L2 stored in the internal space 454 flows into the through hole 452a serving as the discharge port. In this way, the discharge of the plating solution L2 is promoted. The waste liquid flowing into the pipe 494 is recovered by the plating solution supply and discharge unit 49.

[0107] The support mode of the isolation tank 450 connected via the rotatable hinge member 455c by the lifting guide mechanism 464 allows such an inclination of the isolation tank 450. That is, in each of the pair of lifting guide mechanisms 464, 464 arranged with different positions in the Y direction, the movable rods 464b move up and down independently of each other, so that the isolation tank 450 can be in an inclined state.

[0108] Further, flexible joints 493 and 495 are inserted into the plating liquid supply pipe 492 and the discharge pipe 494 connected to the isolation tank 450, respectively. Therefore, it is possible to incline the isolation tank 450 while these pipes are connected.

[0109] Figs. 9 to 11 are diagrams for explaining the lifting operation of the isolation tank in more detail, and more specifically, diagrams for explaining the action of the roller member 455f. In these diagrams, for ease of understanding, some configurations that are not necessary for the explanation may be omitted from the description or the structure may be simplified for illustration. Also, in order to explain the action of the roller member 455f hidden by the hinge member 455c, its installation position is shown changed to the (+Y) side from the actual position.

[0110] As shown in Fig. 9, a rotatable roller member 455f is provided at the upper part of the isolation tank 450. Also, a tapered member 468 having an inclined surface with its lower surface inclined with respect to the horizontal plane is attached to a position on the lower surface of the support frame 461 that hits directly above the roller member 455f. When the lifting mechanism 47 operates and the wire 471 is wound up as shown by the dashed arrow, the isolation tank 450 is pulled upward while in an inclined posture, and the roller member 455f and the tapered member 468 gradually approach each other.

[0111] As shown in Fig. 10, the roller member 455f abuts against the lower surface of the tapered member 468, that is, the inclined surface, thereby restricting further upward displacement of the roller member 455f. When the isolation tank 450 is further pulled upward in this state, the upward movement of the (-Y) side end of the isolation tank 450 is restricted by the roller member 455f and the tapered member 468, while there is room for further upward movement at the (+Y) side end of the isolation tank 450.

[0112] For this reason, the (+Y) side end of the isolation tank 450 is further lifted, and finally, as shown in Fig. 11, the isolation tank 450 is held in a horizontal posture. In this way, in the process of pulling the isolation tank 450 out of the plating tank 41, the isolation tank 450 is temporarily tilted to discharge the plating solution L2, but finally the isolation tank 450 is returned to the horizontal posture.

[0113] When the isolation tank 450 descends from the position where it has retreated upward, the operation is the reverse of the above. That is, the isolation tank 450 temporarily changes from the horizontal posture to the inclined posture, but returns to the horizontal posture when it is accommodated in the plating tank 41. In this way, it becomes possible to receive a new supply of the plating solution L2.

[0114] Fig. 12 is a diagram showing the lifting operation of the entire support mechanism. Above, the operation of the lifting guide mechanism 464 for lifting and lowering the isolation tank 450 with respect to the support frame 461 has been described. As shown in Fig. 7, this support mechanism 460 has a structure in which the support frame 461 is supported by a lifting guide mechanism 465 attached to the support frame 462, and further the support frame 462 is supported by a lifting guide mechanism 466 attached to the support frame 463.

[0115] The structure and operation of the lifting guide mechanisms 465 and 466 are the same as those of the lifting guide mechanism 464, except that the damper mechanism is omitted. Therefore, the support frame 461 is movable up and down with respect to the support frame 462, and further, the support frame 462 is movable up and down with respect to the support frame 463. Thus, in the support mechanism 460, as shown in the upper diagram of FIG. 12, the support frames 461 and 462 can transition between the state where they are lowered to the maximum extent with respect to their respective support bodies and the state where they are raised to the maximum extent with respect to their respective support bodies, as shown in the lower diagram of FIG. 12. Since the support frame 463 is fixed to the upper frame 11 that constitutes the device housing 10, such a structure contributes to increasing the vertical movement range of the isolation tank 450.

[0116] FIG. 13 is a block diagram showing the electrical configuration of this plating device. In the plating device 1 configured as described above, the control unit 9 controls each part of the device to cause the plating device 1 to perform a predetermined process. As the hardware configuration of the control unit 9, for example, the same as that of a general computer device can be used. That is, as the control unit 9, one including a CPU (Central Processing Unit) 91, a memory 92, a storage 93, an input unit 94, a display unit 95, an interface unit 96, etc. can be used.

[0117] The memory 92 temporarily stores various data generated during the process of processing. The storage 93 stores various data and the control program 931 in the long term. The input unit 94 and the display unit 95 perform the user interface function. The interface unit 96 is responsible for communication with external devices and the like.

[0118] The CPU 91 reads out and executes a control program 931 stored in advance in the storage 93, and based on this, controls each part of the device to perform a predetermined operation, thereby realizing various operations described later. For this purpose, the CPU 91 software-implements functional blocks such as a conveyance control unit 911 that controls the operation of the conveyance unit 2, a chuck control unit 912 that controls the operation of the chuck unit 40, a supply / discharge control unit 913 that controls the supply sources of various fluids and is in charge of their supply and discharge, a flow rate control unit 914 that controls the valves on the pipes to adjust the flow rate of the flowing fluid, and a power supply control unit 915 that controls the power supply to the electrodes by the power supply unit 7. At least a part of these functional blocks may be configured as dedicated hardware, for example.

[0119] Note that in the specification and drawings of Japanese Patent Application No. 2022-094449 previously disclosed by the applicant of the present application, a plating apparatus having a basic configuration similar to that of the plating apparatus 1 of the present embodiment is disclosed, and there are also detailed descriptions about the structure of each part of the apparatus, its functions, the operation of the apparatus, etc.

[0120] Next, the operation of the plating apparatus 1 configured as described above will be described. The basic operation flow of the plating apparatus 1 is generally as follows. The unprocessed substrate S is carried into the loading unit 3. The substrate S is conveyed from the loading unit 3 to the plating processing unit 4, and the plating processing unit 4 executes an electrolytic plating process on the substrate S to form a metal film on its surface (upper surface Sa). The plated substrate S is subjected to a rinsing process in the rinsing processing unit 5 and finally carried out to the unloading unit 6.

[0121] FIG. 14 is a flowchart showing the plating process. FIG. 15 is a diagram schematically showing the operations of each part. More specifically, FIG. 15 shows the operations of each part along with the passage of time T, with the direction from top to bottom as the time axis. After an unprocessed substrate S is provided to the loading unit 3 at time T0, each part of the device executes the following operations. In the figure, the content in parentheses represents the initial state of each part. Also, in FIG. 15, the thick-lined vertical lines of each processing unit mean that the substrate S is present in the corresponding processing unit.

[0122] Each part of the plating apparatus 1 is set to a predetermined initial state in advance. In the initial state, the chuck mechanism 400 is positioned at the plating position above the plating tank 41, and the upper chuck 411 and the lower chuck 421 are positioned at the upper positions where they do not interfere with the plating tank 41. Note that, as long as it does not hinder the conveyance of the substrate S along the conveyance path P, the upper chuck 411 and the lower chuck 421 may be positioned lower.

[0123] In the loading section 3, the loaded substrate S is temporarily held. In the plating section 4, the shutters 41a and 41b of the plating tank 41 are opened, enabling the conveyance of the substrate S along the conveyance path P. At this time, in the plating tank 41, the plating solution supplied from the plating solution supply / drain section 49 is stored up to a height at which it does not flow out from the opening. Also, in the anode electrode unit 45, the isolation tank 450 is retracted upward, and no plating solution is stored in its internal space 454. Also in the rinsing section 5, the shutters 51a and 51b of the rinsing tank 51 are opened, enabling the conveyance of the substrate S along the conveyance path P. At the unloading section 6, the substrate S does not exist at this point.

[0124] At time T1, the conveyance section 2 starts to convey the substrate S, and the substrate S is conveyed along the conveyance path P in the conveyance direction Dt (+Y direction) and is finally conveyed to the plating tank 41 (step S101). In FIG. 15, the dashed arrow represents the transfer of the substrate S by the conveyance section 2.

[0125] When the substrate S is loaded into the plating tank 41, the shutters 41a and 41b are closed. The upper chuck 411 and the lower chuck 421 of the chuck mechanism 400 descend toward the substrate S accommodated in the plating tank 41 and grip the substrate S (step S102). Also, in the anode electrode unit 45, the isolation tank 450 descends and is disposed opposite to the upper surface of the substrate S held in the plating tank 41. Note that, in a mode where the substrate S is conveyed to the plating tank 41 with the isolation tank 450 having descended in advance, this may also be possible.

[0126] In this state, the plating solution L is supplied from the plating solution supply / discharge unit 49 to the plating tank 41 (step S103). In parallel with this, the plating solution L2 is supplied from the plating solution supply / discharge unit 49 to the isolation tank 450. As a result, the substrate S is immersed in the plating solution L in the plating tank 41, the anode electrode 451 is immersed in the plating solution L2 in the isolation tank 450, and a state is realized in which the lower surface of the electrolytic diaphragm 453 on the bottom surface of the isolation tank 450 is in contact with the plating solution L in the plating tank 41 (Fig. 6(a)).

[0127] Then, by outputting a predetermined current from each output unit 71a etc. of the power supply unit 7 (step S104), the substrate S is plated. By bringing cathode electrodes extending long in the Y direction into contact with both end portions in the X direction of the upper surface Sa of the substrate S, variations in the current density on the upper surface Sa of the substrate S can be suppressed, and a plating film with good uniformity can be formed.

[0128] At this time, the chuck mechanism 400 and the transfer roller 21 are interlocked to swing the substrate S in the plating tank 41 (step S105), so that the uniformity of the plating film can be further improved. Specifically, by the operation of the moving mechanism 43, the support frame 430 that supports the chuck mechanism 400 alternately repeats movement in the (+Dt) direction and movement in the (-Dt) direction. As a result, the chuck mechanism 400 attached to the support frame 430 integrally reciprocates in the Y direction, and the substrate S held by the chuck mechanism 400 swings in the Y direction in the plating solution L.

[0129] At this time, the transfer roller 21 is interlocked with the support frame 430. That is, when the support frame 430 moves in the (+Y) direction and the chuck mechanism 400 moves the substrate S in the (+Y) direction, the transfer roller 21 rotates forward, that is, rotates in the direction of transporting the substrate S in the transport direction Dt. On the other hand, when the support frame 430 moves in the (-Y) direction and the chuck mechanism 400 moves the substrate S in the (-Y) direction, the transfer roller 21 rotates reversely, that is, rotates so as to transport the substrate S in the direction opposite to the transport direction Dt (-Dt).

[0130] By oscillating the substrate S in the plating solution L in this way, the plating solution L can be stirred to reduce the deviation of the ion concentration in the solution and improve the uniformity of the plating film. The oscillation of the substrate S in the plating tank 41 is realized by the interlocking of a chuck mechanism 400 that grips the end of the substrate S and a transfer roller 21 that supports the central portion of the substrate S from the lower surface side. Therefore, it is possible to prevent local stress from being applied to the substrate S and to oscillate the substrate S while maintaining a horizontal posture.

[0131] After the state in which the substrate S is immersed in the plating solution L and the substrate S is oscillated while supplying a current between the electrodes is continued for a certain period of time, the current supply is stopped (step S106), and the plating process is stopped. Then, the plating solution L is discharged from the plating tank 41, and the plating solution L2 is discharged from the isolation tank 450 (step S107). When discharging from the isolation tank 450, with the isolation tank 450 retracted upward by the support mechanism 460, the lifting mechanism 47 operates to lift the (-Y) side end of the isolation tank 450.

[0132] Then, the gripping of the substrate S by the chuck mechanism 400 is released (step S108), the shutter 41b is opened, and at time T2, the transfer unit 2 transfers the substrate S from the plating process unit 4 to the rinsing process unit 5 (step S109). By releasing the gripping of the substrate S after discharging the plating solution L, it is possible to avoid the cathode electrode 412 from contacting the plating solution. Note that there is no such restriction on the anode electrode 451. Therefore, the discharge from the isolation tank 450 can be executed at an arbitrary timing after the current stop. That is, it is not necessary to be simultaneous with the discharge of the plating solution L from the plating tank 41.

[0133] In the rinsing process unit 5, when the substrate S is accommodated in the rinsing tank 51, the shutters 51a and 51b are closed, the rinsing solution is supplied from the rinsing solution supply / discharge unit 59, and the substrate S is rinsed (step S110). After the rinsing process is performed for a predetermined period of time, the supply of the rinsing solution is stopped, the shutter 51b is opened, and at time T3, the substrate S is discharged to the carry-out unit 6 (step S111).

[0134] In addition, when discharging the plating solution from the plating tank 41, it is not necessary to completely discharge the liquid in the tank. That is, as long as the liquid is discharged to such an extent that the substrate S supported in the tank is exposed from the liquid and can be carried out, there is no problem even if liquid remains in the tank. Rather, by leaving the liquid, it becomes possible to reduce the amount of liquid required to fill the tank during the treatment of the next substrate S. This contributes to reducing the consumption of liquid and reducing the environmental load.

[0135] On the other hand, after the chuck mechanism 400 releases the grip on the substrate S, it undergoes a cleaning process (step S112) to remove the plating solution adhering to the upper chuck 411 and the lower chuck 421. The content of the cleaning process is arbitrary, but for example, one example is as follows. That is, the support mechanism 43 moves the support frame 430 in the (-Y) direction to position each chuck mechanism 400 at the cleaning position above the vat 44. In this state, the cleaning mechanism 48 cleans the chuck mechanism 400, more specifically, the upper chuck 411 and the lower chuck 421, by appropriately supplying a cleaning liquid and jetting air.

[0136] In the movement of the chuck mechanism 400 between the plating position and the cleaning position, as shown by the dotted line in FIG. 2, the upper chuck 411 and the lower chuck 421 are in a state of being retracted upward by the elevating mechanisms 412 and 422. Thereby, it is prevented that the upper chuck 411 and the lower chuck 421 contact the wall surface of the plating tank 41 during the movement. The Z-direction positions of the upper chuck 411 and the lower chuck 421 at this time are hereinafter referred to as "upper positions".

[0137] The chuck mechanism 400 after cleaning is returned to the plating position (step S113). By thus cleaning the chuck mechanism 400, it is possible to prevent the remaining adhered plating solution from adhering to the substrate S when performing the treatment for the next substrate S. If there is another substrate S to be processed, the process returns to step S101 and the above process is repeated.

[0138] As described above, in the plating apparatus of this embodiment, the substrate S, which is the object of the plating process, is supported in the plating bath 41 in a horizontal posture in which one main surface Sa, which becomes the surface to be plated, faces upward, that is, in a so-called face-up state. The cathode electrode 412 contacts the peripheral edge of the substrate S, and the anode electrode 451 is disposed opposite to the upper surface of the substrate S.

[0139] However, the anode electrode 451 and the substrate S are separated by an electrolytic diaphragm 453. Thereby, while a path for metal ions, which are the materials of the plating film, is secured between the anode electrode 451 and the substrate S, the anode electrode 451 and the substrate S are isolated from non-soluble components and liquid components. Therefore, it is possible to avoid the adhesion of anode slime caused by the free substances from the anode electrode 451 to the substrate S and the deterioration of the quality of the plating film.

[0140] Further, the anode electrode 451 is divided into a plurality of electrode plates 451a to 451i, and output units 71a to 71i, which are constant current sources of the power supply unit 7, are individually connected to each electrode plate. And the output current from each of the output units 71a to 71i can be individually set. For this reason, even when the substrate S is large, it is possible to suppress the deviation of the current density distribution in the plane of the substrate S and to make the film thickness of the plating film uniform.

[0141] Regarding the replacement of the plating solution in the isolation tank 450, due to the fact that the lower surface of the isolation tank 450 is disposed opposite to the substrate S, it is difficult to provide a mechanism for draining below the isolation tank 450. Therefore, in this embodiment, a discharge port is provided on the side wall surface of the isolation tank 450. Further, in order to allow the drainage to proceed efficiently, a mechanism for lifting the end of the isolation tank 450 and inclining the bottom surface is provided on the side opposite to the side wall surface where the discharge port is provided. Thereby, the promotion of the discharge of the plating solution is achieved.

[0142] That is, the isolation tank 450 of this embodiment can switch its posture between a horizontal posture with a horizontal bottom surface and an inclined posture with a bottom surface significantly inclined with respect to the horizontal plane. In the horizontal posture, the anode electrode 451 can be opposed to the substrate S to perform plating treatment. On the other hand, in the inclined posture, the plating solution remaining in the internal space 454 of the isolation tank 451 can be efficiently discharged, and then by receiving a new plating solution, the plating solution stored in the internal space 454 can be maintained in a fresh state.

[0143] <Modification Example> FIG. 16 is a diagram showing a modification example of the anode electrode. The anode electrode 451 in the above embodiment is formed by arranging nine electrode plates 451a to 451i having substantially the same shape in a 3×3 matrix. However, the pattern of dividing the anode electrode into a plurality of parts is not limited to this, and various patterns are conceivable. For example, in the anode electrode 456 shown in FIG. 16(a), electrode plates of substantially the same shape are arranged in a 5×4 matrix. Thus, the number of arranged electrode plates is not limited to that of the above embodiment and is arbitrary.

[0144] Also, in the anode electrode 457 shown in FIG. 16(b), large-area electrode plates are arranged in the central part where it is easy to obtain a relatively uniform current density, while in the peripheral part and corner part where the bias of the current density is likely to occur, the area of the electrode plates is made smaller to facilitate fine adjustment of the current density distribution. Thus, the shape and size of each electrode plate can also be appropriately determined according to the purpose.

[0145] Moreover, the anode electrode 458 shown in FIG. 16(c) has a structure in which the periphery of a rectangular electrode plate arranged in the central part is multiply surrounded by a frame-shaped electrode plate having a rectangular outer shape and an opening in the center. Such a structure can also achieve the purpose of setting the current density independently between the central part and the peripheral part of the substrate S.

[0146] Thus, various anode electrode division patterns can be considered. When setting the division pattern and distributing current to each electrode plate, for example, a method can be adopted in which the current density distribution is actually measured through preliminary experiments and determined based on the results. Specifically, in a region on the substrate surface where the variation in current density is small, there is little need to finely divide the electrode plate facing this region. Conversely, in a region where the variation in current density is large, by finely dividing the electrode plate, it is possible to easily adjust the current density distribution. Also, by making the current set value smaller in regions where the current density is higher, it is possible to achieve uniform current density.

[0147] In particular, when chucking and holding two opposite sides out of the four sides of a rectangular substrate, since the cathode electrode is arranged near these two sides, it is expected that the current distribution will be significantly different from that near the two sides that are not held. Even in such a case, by adjusting the division pattern of the anode electrode and the supply current value to each electrode plate, it is possible to suppress the deviation of the current density distribution and improve the uniformity of the plating film.

[0148] FIG. 17 is a diagram schematically showing a modified example of the support mechanism in the anode electrode unit. Here, components that are common or equivalent to those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the above-described embodiment, the isolation tank 450 is tilted by the lifting mechanism 47 winding up the wire 471 attached to the isolation tank 450 at a position offset in the Y direction from the midpoint between the two hinge members 455c arranged in the Y direction. Instead of this, for example, as shown in FIG. 17(a), a configuration can be adopted in which the isolation tank 450 is supported by two suspension mechanisms 467a and 467b having significantly different spring constants. That is, the suspension mechanisms 467a and 467b attached to the support frame 461 are coupled to the frame 455 of the isolation tank 450, whereby the isolation tank 450 is supported.

[0149] In order to maintain the isolation tank 450 in a horizontal posture, it is preferable to appropriately provide a stopper 469 that restricts the downward displacement of the isolation tank 450. Note that the shape and arrangement position of the stopper are not limited to the illustration, and are arbitrary as long as the downward displacement of the isolation tank 450 can be directly or indirectly restricted.

[0150] As shown in FIG. 17(b), when the support mechanism 460 raises the support frame 461, since the spring constants of the two suspension mechanisms 467a and 467b are different from each other, the isolation tank 450 is in an inclined state. In the example shown in FIG. 17(b), the spring constant of the support mechanism 467a provided on the (-Y) side is larger than the spring constant of the suspension mechanism 467b provided on the (+Y) side. For this reason, the (-Y) side end of the isolation member 450 is lifted. Thereby, the same operation as in the above embodiment can be obtained. Note that when the support mechanism 460 itself supports the isolation tank 450 through a structure for tilting the isolation tank 450 in this way, the lifting mechanism 47 may lift the isolation tank 450 with the intermediate position in the Y direction of the two hinge members 455c as the acting point.

[0151] <Others> As described above, in the above embodiment, the plating apparatus 1 corresponds to the "plating apparatus" of the present invention, and the plating tank 41, the chuck mechanism 400, the cathode electrode 412, and the anode electrode 451 function as the "processing tank", "holding part", "cathode electrode", and "anode electrode part" of the present invention, respectively. Further, the electrode plate 451e disposed at the center of the electrode plates 451a to 451i corresponds to the "first electrode" of the present invention, and the other electrode plates correspond to the "second electrode". Also, in the modified examples shown in FIGS. 16(a) to 16(c), the electrode plate located on the outermost periphery can be regarded as the "second electrode", and the electrode plate located inside it can be regarded as the "first electrode".

[0152] In the above-described embodiment, the frame 452 of the isolation tank 450 functions as the "shielding frame" of the present invention. Also, the power supply unit 7 functions as the "power supply unit" of the present invention, and each of the output units 71a to 71i functions as the "current output unit" of the present invention. Further, the plating solution L and the plating solution L2 correspond to the "plating solution" of the present invention.

[0153] Note that the present invention is not limited to the above-described embodiment, and various modifications can be made other than those described above without departing from the spirit thereof. For example, in the above-described embodiment, the chuck mechanism 400 is provided on two opposing sides of the rectangular substrate S. However, instead of this, all four sides or three of the four sides may be gripped by the chuck mechanism.

[0154] Also, for example, in the above-described embodiment, the chuck mechanism 400 grips the substrate S conveyed into the plating tank 41 by the conveying roller 21. However, the conveying means is not limited to rollers and is arbitrary. On the other hand, an aspect of conveying the substrate while being gripped by the chuck mechanism is also conceivable. In this case, the conveying means is not an essential configuration, but in order to stably maintain the posture of a large substrate, it is desirable to provide some backup means for supporting the central portion of the substrate S from below.

[0155] Note that the substrate to be processed does not need to be a geometric rectangle in the strict sense. For example, even a substrate having some irregularities on any side is sufficient as long as the envelope outer shape can be regarded as being approximately rectangular.

[0156] Also, for example, the power supply unit 7 in the above-described embodiment includes a constant current output source corresponding individually to each electrode plate constituting the anode electrode 451. Instead of this, for example, the power supply unit may be configured by a combination of a single voltage source and a plurality of current limiting elements provided corresponding to each electrode plate.

[0157] Also, for example, in the power supply unit 7 of the above-described embodiment, individual output units are provided for all of the electrode plates constituting the anode electrode 451. However, some of the electrode plates may be electrically connected in parallel and connected to a common output unit. For example, even in the case of the anode electrode 456 having the division pattern shown in FIG. 16(a), by connecting some of the electrode plates in parallel, it is possible to realize substantially the same division pattern as the anode electrode 457 shown in FIG. 16(b). Further, a configuration may be adopted in which the connection relationship between the electrode plate and the power supply is changed as necessary.

[0158] Also, for example, in the above-described embodiment, the anode electrode 451 is divided into a plurality of electrode plates. However, the effect of preventing the adhesion of anodic slime to the substrate, which is obtained by isolating the anode electrode and the substrate with a separation tank, can be similarly obtained in a plating apparatus in which the anode electrode is constituted by a single electrode plate.

[0159] Also, in the above-described embodiment, the liquid stored in the plating tank 41 and the liquid stored in the separation tank 451 are plating liquids having the same or substantially the same composition. However, even when the compositions of these liquids are different, the above-described configuration is effective. That is, each liquid can be independently supplied and discharged, and it is possible to avoid their mixing.

[0160] Also, the anode electrode 451 of the above-described embodiment contains a metal (for example, copper) that becomes a material for the plating film, and is a soluble electrode that is consumed as the plating process progresses. However, even if the electrode material is an insoluble electrode that does not directly contribute to the plating reaction, problems such as non-uniformity of the film thickness and film quality due to the deviation of the current density distribution can similarly occur. Therefore, also in the case of an insoluble electrode, making it possible to individually adjust the current as a divided structure as described above effectively functions to optimize the current density distribution and achieve uniformization of the film thickness.

[0161] As described by way of example in the above specific embodiments, in the plating apparatus according to the present invention, for example, the second electrode may be arranged so as to surround the first electrode in the horizontal direction. According to such a configuration, it becomes possible to independently adjust the current density between the central portion and the peripheral portion of the substrate.

[0162] Also, for example, the lower surface of the first electrode and the lower surface of the second electrode may be arranged such that they form the same plane parallel to one main surface. According to such a configuration, it is possible to enhance the correlation between the current output from each electrode and the current flowing near the surface of the substrate, and to improve the controllability of the current density.

[0163] Also, for example, with respect to the distance between the first electrode and the second electrode in the horizontal direction, it can be made smaller than the distance between the first electrode and one main surface in the vertical direction. If the interval between the electrodes is wide, the area of the one main surface of the substrate that does not face the electrodes becomes large, and unevenness in the current density is likely to occur. By realizing the above-described distance relationship, it is possible to suppress current unevenness by utilizing the spread of the current from the electrodes.

[0164] Also, for example, a shielding frame may be further provided to surround the sides of the first electrode and the second electrode together to shield the flow of ions. In this case, it is preferable that the cathode electrode contacts one main surface outside the shielding frame in plan view. According to such a configuration, by shielding the shortest path of the current from the anode electrode portion to the cathode electrode with the shielding frame, it is possible to reduce the current that does not contribute to the plating process. This not only helps to make the film thickness of the plating film uniform but also serves to suppress the consumption of unnecessary electrical energy.

[0165] Also, for example, at least one of the first electrode and the second electrode may be provided in plurality, and in that case, each of the plurality of electrodes may be connected to a different current output portion. According to such a configuration, it is possible to more finely adjust the current density for each position, so that it becomes possible to bring the current density of the entire substrate closer to a more uniform state.

[0166] Further, in the plating apparatus and plating method according to the present invention, the first electrode and the second electrode may contain a material that is consumed to form a plating film on one main surface. Such an electrode is a so-called soluble electrode in which the material dissolves and is consumed as the plating process progresses. In this case, there is a concern that the current distribution may change as the electrode is consumed, but in the present invention, the output current is set, and the plating process progresses under the condition that a uniform film thickness can be obtained, so the variation in the degree of electrode consumption is small. Therefore, it is possible to reduce the fluctuation of the current density as the plating process progresses. Of course, even in the case of an insoluble electrode, making the structure such that the electrodes can be divided and the current can be adjusted individually is effective for optimizing the current density distribution and achieving uniform film thickness.

[0167] Also, for example, when, for each of the first electrode and the second electrode, the area of the surface facing one main surface is defined as the electrode area, and the value obtained by dividing the input current value by the electrode area is defined as the electrode current density, in the power supply unit, it is preferable that the output current of each current output unit is set so that the electrode current density in the first electrode is larger than the electrode current density in the second electrode. By introducing the concept of electrode current density in this way, it becomes possible to perform adjustment considering not only the current value but also the electrode area. This enables setting of the current value from the viewpoint of the current density on the substrate. And by increasing the electrode current density in the first electrode facing the central portion of the substrate, it is possible to suppress the phenomenon that the film thickness is larger at the peripheral portion than at the central portion and achieve uniform film thickness.

[0168] Also, for example, the output current of each current output unit may be changeable by user operation. Even if a uniform current density distribution is realized, the film thickness of the plating film may not be uniform depending on the size and shape of the substrate. However, an automatic control technique for the amount of current for correcting such a state has not been established. By leaving room for adjustment by user operation, it is possible to realize the conditions for making the film thickness uniform even in such cases.

Industrial Applicability

[0169] The present invention is suitable for a technique of forming a film by plating one main surface of a substrate. In particular, it has a remarkable effect when a large rectangular substrate is the object to be processed.

Explanation of Signs

[0170] 1 Plating apparatus 2 Conveying section 4 Plating processing section 7 Power supply section 41 Plating tank (processing tank) 40, 47 Chuck section (holding section) 71a to 71e Output section (current output section) 400 Chuck mechanism (holding section) 412 Cathode electrode 413, 423 Lifting mechanism 450 Isolation tank 451 Anode electrode (anode electrode section) 451a to 451d, 451f to 451i Electrode plates (second electrodes) 451e Electrode plate (first electrode) 452 Frame body (shielding frame) 453 Anode electrode L, L2 Plating solution (plating solution) S Substrate Sa Upper surface (one main surface) of (substrate S)

Claims

1. A plating apparatus for plating at least one main surface of a rectangular substrate, comprising: a treatment tank for storing a plating solution; a holding unit for holding the substrate in a horizontal posture with the one main surface facing upward in the treatment tank; a cathode electrode that contacts a peripheral portion of the one main surface of the substrate held by the holding unit; an anode electrode portion disposed above the substrate held by the holding unit and having a lower surface disposed opposite to the one main surface; a power supply unit connected to the anode electrode portion and the cathode electrode; wherein the anode electrode portion includes at least one first electrode facing a central portion inside the peripheral portion of the one main surface; and at least one second electrode facing the one main surface outside the central portion; and the power supply unit has a plurality of current output units whose output currents can be individually set and changed, and the first electrode and the second electrode are connected to different ones of the current output units.

2. The plating apparatus according to claim 1, wherein the second electrode is disposed so as to surround the first electrode in the horizontal direction.

3. The plating apparatus according to claim 1, wherein a lower surface of the first electrode and a lower surface of the second electrode form the same plane parallel to the one main surface.

4. The plating apparatus according to claim 1, wherein a distance between the first electrode and the second electrode in the horizontal direction is smaller than a distance between the first electrode and the one main surface in the vertical direction.

5. comprising a shielding frame that collectively surrounds the sides of the first electrode and the second electrode to shield the flow of ions; wherein the cathode electrode contacts the one main surface outside the shielding frame in a plan view.

6. The plating apparatus according to any one of claims 1 to 5, wherein the first electrode and the second electrode contain a material consumed to form a plating film on the one main surface.

7. The plating apparatus according to any one of claims 1 to 5, wherein a plurality of the first electrodes are provided, and each of the plurality of first electrodes is connected to a different one of the current output units.

8. The plating apparatus according to any one of claims 1 to 5, wherein a plurality of the second electrodes are provided, and each of the plurality of second electrodes is connected to a different one of the current output units.

9. For each of the first electrode and the second electrode, when the area of the surface facing the one main surface is defined as the electrode area, and the value obtained by dividing the input current value by the electrode area is defined as the electrode current density, in the power supply unit, the output current of each of the current output units is set such that the electrode current density in the first electrode is greater than the electrode current density in the second electrode, the plating apparatus according to any one of claims 1 to 5.

10. The output current of each of the current output units can be changed and set by a user operation, the plating apparatus according to any one of claims 1 to 5.

11. A plating method for plating at least one main surface of a rectangular substrate, a step of holding the substrate by a holding unit in a horizontal posture with the one main surface facing upward in a treatment tank for storing a plating solution; a step of bringing a cathode electrode into contact with a part of the one main surface of the substrate held by the holding unit, and arranging an anode electrode unit above the substrate so as to face the one main surface; a step of outputting a current from a power supply unit connected between the anode electrode unit and the cathode electrode and comprising the anode electrode unit has at least one first electrode facing a central portion inside the peripheral portion of the one main surface and at least one second electrode facing the one main surface outside the central portion; the power supply unit outputs the current from each of the current output units that can individually set and change the output current with respect to the first electrode and the second electrode and are different from each other, the plating method.

12. The first electrode and the second electrode contain a material consumed for forming a plating film on the one main surface, the plating method according to claim 11.

13. For each of the first electrode and the second electrode, when the area of the surface facing the one main surface is defined as the electrode area, and the value obtained by dividing the input current value by the electrode area is defined as the electrode current density, each of the current output units outputs a current such that the electrode current density in the first electrode is greater than the electrode current density in the second electrode, the plating method according to claim 11 or 12.

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