Plating apparatus and plating method

Abstract

To provide a plating film with uniform thickness and quality even in a configuration in which a plating treatment is performed while a large-sized substrate and a corresponding anode electrode are arranged face to face.SOLUTION: A plating apparatus of the present invention is used for plating at least one principal surface of a substrate. The plating apparatus comprises: a treatment tank for storing a plating solution; a holding part for holding the substrate in the treatment tank with the principal surface facing upward in a horizontal position; a cathode electrode contacting the peripheral part of the principal surface of the substrate held by the holding part; an anode electrode, which is arranged over the substrate held by the holding part, and the bottom surface of which is oppositely arranged to the principal surface; and a solution supply part having an outlet open toward a gap space sandwiched by the anode electrode and the principal surface, for supplying the solution from the outlet to the plating solution filling the gap space.SELECTED DRAWING: Figure 9

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 substrate such as a printed wiring board or a glass substrate. [Background technology]

[0002] A technology for forming a thin metal film by plating on the surface of various substrates such as semiconductor substrates, printed wiring substrates, and glass substrates is widely used. For example, in Patent Document 1, in a dip-type plating device for forming a thin metal film on a semiconductor substrate, the plating solution is discharged from pipes arranged in a grid pattern in a treatment tank to homogenize the plating solution in the treatment tank. This prevents the thickness of the plating film from becoming uneven due to the unevenness of the plating solution composition. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-026708 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, substrates have become larger, and large substrates with sides exceeding one meter are being manufactured. For such large substrates, it is difficult to hold the substrate vertically and transport it as described in Patent Document 1, and the substrate must be transported horizontally with the surface to be plated facing upwards using a conveyor or the like. In addition, in order to suppress unevenness in the film thickness caused by bias in the current density distribution, it is necessary to arrange an anode electrode so as to face the entire upper surface of the substrate.

[0005] In such a configuration, the composition of the plating solution gradually changes in the gap space between the substrate and the anode electrode as the plating reaction progresses, which impairs the homogeneity of the plating film. In particular, in the central part of the substrate, a fresh supply of plating solution from the outside cannot be expected, which causes problems such as insufficient film thickness and non-uniform film quality. However, no technology capable of dealing with this problem has been proposed so far.

[0006] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a plating apparatus and a plating method that are capable of obtaining a plating film of uniform thickness and quality, even when performing plating processing by opposing a large substrate to a corresponding anode electrode. [Means for solving the problem]

[0007] One aspect of the present invention is a plating apparatus for plating at least one main surface of a substrate, the plating apparatus comprising: a treatment tank for storing a plating solution; a holding unit for holding the substrate in a horizontal position within the treatment tank with the main surface facing upward; a cathode electrode for contacting a peripheral portion of the main surface of the substrate held in the holding unit; an anode electrode for contacting an upper portion of the substrate held in the holding unit with its lower surface facing the main surface; and a liquid supply unit for supplying liquid from the discharge port toward the plating solution that fills the gap space.

[0008] Also, one aspect of the present invention is a plating method for plating at least one main surface of a substrate, the plating method comprising the steps of: holding the substrate in a horizontal position with the one main surface facing upward in a treatment tank storing a plating solution by a holder; bringing a cathode electrode into contact with a part of the one main surface of the substrate held by the holder, while disposing an anode electrode above the substrate so as to face the one main surface; and applying a voltage between the anode electrode and the cathode electrode. During at least a part of a period during which the voltage is applied between the anode electrode and the cathode electrode, liquid is supplied toward the plating solution filling the gap space from a discharge port that opens toward a gap space sandwiched between the anode electrode and the one main surface.

[0009] In the invention configured as described above, a liquid is supplied to a gap space formed between the anode electrode and the substrate by opposing them and filled with a plating solution. The liquid has the effect of stirring the plating solution filling the gap space, thereby reducing the non-uniformity of the plating solution. It is more preferable that the liquid contains a component that contributes to the plating reaction.

[0010] In particular, when the liquid has the same or substantially the same composition as the plating solution, the replacement of the liquid in the gap space is promoted. Here, the "substantially the same" composition of the liquid means that the main components are common and the basic chemical properties are roughly the same, and includes cases where there are slight differences in the content of each component, and cases where only the presence or absence, type, content, etc. of additives are different.

[0011] Furthermore, in the case where the liquid contains metal ions of the same type as the metal constituting the anode electrode, the metal ions that are consumed in film formation and are lost can be replenished, allowing the plating reaction to be carried out continuously and stably. Effect of the Invention

[0012] As described above, according to the present invention, the non-uniformity of the plating solution filling the gap space between the anode electrode and the substrate is eliminated by supplying the liquid toward the gap space between the anode electrode and the substrate, so that a plating film with uniform thickness and quality can be obtained even when a plating process is performed by placing a large substrate and a corresponding anode electrode facing each other. [Brief description of the drawings]

[0013] [Figure 1] 1 is a diagram showing a schematic configuration of an embodiment of a plating apparatus according to the present invention; [Diagram 2] FIG. 2 is a diagram showing a schematic configuration of a plating processing section. [Diagram 3] FIG. 2 is a diagram showing a schematic configuration of a plating processing section. [Figure 4] FIG. 2 is a diagram showing a schematic configuration of a chuck mechanism. [Diagram 5] FIG. 2 is a diagram showing a schematic configuration of a main part of an anode electrode unit. [Figure 6] FIG. 2 is a diagram showing a schematic diagram of an isolation tank immersed in a plating tank. [Figure 7] FIG. 4 is an external perspective view showing a support mechanism for a separator in the anode electrode unit. [Figure 8] FIG. 2 is a diagram showing a schematic diagram of supply and discharge of plating solution to and from an isolation tank. [Figure 9] 1A to 1C are diagrams illustrating two aspects of a liquid supply mechanism. [Figure 10] FIG. 2 is a diagram showing a first embodiment of a liquid supply mechanism. [Figure 11] FIG. 2 is a diagram showing a piping system in a first embodiment of a liquid supply mechanism. [Figure 12] 11A and 11B are diagrams illustrating the effect of liquid supply. [Figure 13] FIG. 13 is a diagram showing a second embodiment of the liquid supply mechanism. [Figure 14] FIG. 2 is a block diagram showing the electrical configuration of the plating apparatus. [Figure 15] 1 is a flowchart showing a plating process. [Figure 16]FIG. 2 is a diagram showing a schematic operation of each unit. [Figure 17] FIG. 13 is a diagram showing a modified example of the anode electrode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, specific aspects of the plating apparatus according to the present invention will be described with reference to specific embodiments.

[0015] FIG. 1 is a diagram showing a schematic configuration of one embodiment of a plating apparatus according to the present invention. This plating apparatus 1 is an apparatus for forming a metal (e.g., gold) film by electrolytic plating on at least one main surface of various substrates S (hereinafter simply referred to as "substrate") such as semiconductor substrates, printed wiring substrates, and glass substrates. For the following explanation, an XYZ Cartesian coordinate system is defined as shown in FIG. 1. FIG. 1 is a diagram showing a side view of the plating apparatus 1, in which the horizontal direction and perpendicular to the paper surface of FIG. 1 is defined as the X direction, and the horizontal direction perpendicular to the X direction and along the paper surface of FIG. 1 is defined as the Y direction. The vertical direction is defined as the Z direction. In each diagram, the dotted arrows indicate the movement directions of each member.

[0016] The plating apparatus 1 has a configuration in which each part described below is assembled in a housing 10 formed by combining multiple frame members. In Fig. 1 and the following figures, in order to avoid cluttering the drawings, some components may be omitted as appropriate. Specifically, components such as a holding mechanism for holding components, a cover for covering the components, and a mechanism for attaching them to the housing 10 may be omitted from illustration because they contribute relatively little to the establishment of the invention and because appropriate publicly known technology can be applied to their structures and therefore no special explanation is considered to be required.

[0017] FIG. 1 is a front view of a plating apparatus 1. The plating apparatus 1 is provided with a transport section 2 that transports a substrate S along the Y direction. The transport section 2 includes a plurality of transport rollers 21 arranged along the Y direction. The transport rollers 21 are each supported by a support mechanism (not shown) so as to be rotatable about the X direction as their axial direction. The transport rollers 21 are rotated by a drive mechanism (not shown) so that the transport section 2 transports the substrate S in the Y direction in a horizontal position. The rectangular substrate S is transported with one of the four peripheral sides at the front. In the following, the transport path of the substrate S is represented by the symbol P, and the transport direction is represented by the symbol Dt.

[0018] The plating apparatus 1 further includes a carry-in section 3, a plating processing section 4, a rinsing processing section 5, an unloading section 6, a power supply section 7, and a control section 9. The carry-in section 3, the plating processing section 4, the rinsing processing section 5, and the unloading section 6 are arranged in this order along the transport direction Dt (Y direction) of the substrate by the transport section 2. That is, in this plating apparatus 1, the substrate S is subjected to necessary processing in each of the above-mentioned processing sections while being transported in the Y direction by the transport section 2.

[0019] The loading section 3 receives and temporarily holds the unprocessed substrate S transported from the outside, and supplies the substrate S to the plating section 4 at the required timing. The plating section 4 is the processing main body that executes the plating method according to the present invention, and performs plating by immersing the substrate S in a plating solution. The configuration and operation of the plating section 4 will be described in detail later.

[0020] The rinsing processing unit 5 includes a rinsing tank 51, a tray 52, and a rinsing liquid supply / discharge unit 59. The rinsing tank 51 is capable of storing a rinsing liquid in an internal space having a size sufficient to accommodate the substrate S. An opening is provided on the Y-direction side surface of the rinsing tank 51 at a portion overlapping the transport path P, and shutters 51a, 51b are provided for the opening in a manner that allows it to be opened and closed freely.

[0021] The tray 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 liquid in the plating processing unit 4. Water, for example, is used as the rinsing liquid. The unloading unit 6 temporarily holds the substrate S after the rinsing process until it is removed to a post-processing step by an external transport device.

[0022] The power supply unit 7 supplies the 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. The hardware configuration of the control unit 9 may be the same as that of a general computer device. That is, the CPU (FIG. 9) provided in the control unit 9 executes a control program prepared in advance to realize various processes described below. Although not specifically described below, each part of the apparatus operates based on a control command from the control unit 9.

[0023] The plating processing section 4 includes a plating tank 41, vats 42 and 44, a chuck section 40, a moving mechanism 43, an anode electrode unit 45, a cleaning mechanism 48, and a plating liquid supply / discharge section 49. The plating tank 41 is capable of storing plating liquid in an internal space having a size sufficient to accommodate the substrate S. The vat 42 is disposed below the plating tank 41 and receives spilled plating liquid. The chuck section 40 is disposed above the plating tank 41 and holds the substrate S to be plated. The vat 44 is disposed adjacent to the vat 42 below the plating tank 41 on the (-Y) side. The cleaning mechanism 48 cleans the chuck section 40 with an appropriate cleaning liquid (e.g., water). For this purpose, the cleaning mechanism 48 includes a cleaning nozzle 481 (FIG. 2) provided in the vat 44 and a cleaning liquid supply / discharge section 482 that supplies cleaning liquid to the cleaning nozzle 481. The plating solution supply / discharge section 49 supplies plating solution to the plating tank 41 and discharges plating solution from the plating tank 41 as required.

[0024] Figures 2 and 3 are diagrams showing a schematic configuration of the plating processing section. More specifically, Figure 2 is a front view of the main parts of the plating processing section 4 as seen in the (-X) direction, and Figures 3(a) and 3(b) are side views of the plating processing section 4 as seen in the (+Y) direction. In order to avoid complicating the drawings, the anode electrode unit 45 is omitted from Figures 2 and 3(a).

[0025] 1 and 2, openings are provided on the (-Y) side surface and the (+Y) side surface of plating tank 41 at portions overlapping with transport path P, and shutters 41a, 41b that can be opened and closed are provided at the openings. When shutters 41a, 41b are in an open state, substrate S transported along transport path P by transport unit 2 can pass through the openings provided on the sides of plating tank 41. This allows unprocessed substrate S to be carried into plating tank 41 and processed substrate S to be carried out of plating tank 41.

[0026] On the other hand, in the closed state, the opening provided on the side of the plating tank 41 is closed. At this time, the transport path P of the substrate S is blocked, but the plating solution can be stored inside the plating tank 41 beyond the height of the opening. After the substrate S is accommodated in the plating tank 41 with the (-Y) side shutter 41a open, the shutter 41a is closed and the internal space of the plating tank 41 is filled with the plating solution L, so that the substrate S is immersed in the plating solution L and plated. After that, when the plating solution is discharged and the (+Y) side shutter 41b is opened, the liquid level of the plating solution L drops to below the lower end of the opening, and the substrate S after plating is transported to the rinsing section 5. The shutters 41a and 41b may be opened and closed independently of each other, or may be opened and closed integrally.

[0027] 3(a), a rotary motor 23 is coupled to a rotary shaft 22 of the transport roller 21. The rotary motor 23 rotates in response to a control command from the control unit 9, thereby rotating the transport roller 21, thereby transporting the substrate S in the Y direction. Note that some of the rollers may be driven rollers that are not connected to a drive source.

[0028] As shown in Fig. 3(a), two sets of chuck parts 40 are arranged corresponding to both ends in the X direction of the substrate S accommodated in the plating tank 41. Only one set on the (+X) side is shown in Figs. 1 and 2. The two sets of chuck parts 40 are arranged symmetrically with respect to the YZ plane, but have the same basic structure. That is, each chuck part 40 includes at least one chuck mechanism 400, a support frame 430 that supports the chuck mechanism 400, and a movement mechanism 43 that moves the support frame 430 in the Y direction.

[0029] The support frame 430 is supported movably 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 processing section 4 and extending in the Y direction, a slider 432 engaged with the guide rail 431, and a driving source (not shown) for moving 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 motion guide mechanism, a chain drive mechanism, a belt drive mechanism, or the like, can be applied. For example, a single-axis robot in which such a drive mechanism is integrated in advance can be suitably applied.

[0030] A 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. In other words, the moving mechanism 43 operates in response to a control command from the control unit 9 to move the slider 432, thereby moving the chuck mechanism 400 in the Y direction.

[0031] In this embodiment, three sets of chuck mechanisms 400 are attached to one support frame 430 in a line in the Y direction, and they move together in the Y direction as the support frame 430 moves. This allows each chuck mechanism 400 to move back and forth in the Y direction between a "plating position" P1 located above the plating tank 41 and a "cleaning position" P2 located above the vat 44. In FIG. 2, the chuck mechanism 400 at the plating position P1 is shown by a solid line, and the chuck mechanism 400 at the cleaning position P2 is shown by a dotted line. Meanwhile, in FIG. 1, the chuck mechanism 400 at the cleaning position P2 is shown by a solid line.

[0032] The chuck mechanism 400 grips the substrate S to stably maintain the position of the substrate S in the plating tank 41, and brings a built-in cathode electrode into electrical contact with one main surface of the substrate S. A DC voltage is then applied between an anode electrode and a cathode electrode, which will be described later, to form a coating on the one main surface by electrolytic plating. In this case, it is assumed that the coating is formed on the upper surface of the substrate S.

[0033] The chuck mechanisms 400 grip the substrate S at both ends in the X direction, i.e., at both ends in the width direction perpendicular to the transport direction Dt. A large portion of the substrate S at both ends in the X direction is gripped by a plurality of chuck mechanisms 400 provided along the Y direction, i.e., the transport direction Dt of the substrate S. The chuck mechanisms 400 grip the substrate S to stably maintain its position, and can apply a uniform potential over a wide range by contacting the cathode electrode 412 extending in the Y direction with the substrate S. This allows the plating apparatus 1 to form a plating film with good uniformity on the substrate S.

[0034] FIG. 4 is a diagram showing a schematic configuration of the chuck mechanism. More specifically, FIG. 4(a) is a perspective view showing a schematic configuration of the chuck mechanism 400, and FIG. 4(b) is a diagram showing a state in which the chuck mechanism 400 holds the substrate S. In the following, when explaining the structure and operation of the chuck mechanism 400, the chuck mechanism 400 that holds the (-X) side end of the substrate S is mainly illustrated as an example, but the structure and operation of the chuck mechanism that holds the (+X) side end of the substrate S can be understood by considering the same structure inverted around the Z axis. In addition, in order to improve the visibility of the figure, part of the configuration of the chuck mechanism 400 is omitted in FIG. 4(a).

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] A shaft member 413 extending in the Z direction is attached to an upper surface 411a of the upper chuck 411, 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 by using a screw, for example, 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 lifts and lowers the shaft member 413. This causes the upper chuck 411 attached to the lower end of the shaft member 413 to lift and lower. Here, a unit integrally formed including the upper chuck 411, the shaft member 413, the lifting mechanism 414, etc. is referred to as an "upper chuck unit 410."

[0040] Similarly, a shaft member 423 extending in the Z direction is attached to an upper surface 421a of the lower chuck 421, 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 by using a screw, for example, and is detachable. The lifting mechanism 424 has an appropriate linear motion mechanism, for example, a solenoid, a linear motor, or a ball screw mechanism, and lifts and lowers the shaft member 423. This causes the lower chuck 421 attached to the lower end of the shaft member 423 to lift and lower. Here, a unit integrally formed including the lower chuck 421, the shaft member 423, the lifting mechanism 424, etc. is referred to as a "lower chuck unit 420."

[0041] The upper chuck unit 410 is fixed to a support member 401. Therefore, the upper chuck 411 can only move up and down relative to the support member 401. On the other hand, the lower chuck unit 420 is attached to the support member 401 via an advance / retract mechanism 402. Specifically, the support member 403 to which the lower chuck unit 420 is attached is connected to a movable part of the advance / retract mechanism 402 whose movable direction is the X direction. The advance / retract 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.

[0042] Therefore, the lower chuck unit 420 can move in the X direction within a movable range defined by a stopper (not shown) by operation of the advancing / retreating mechanism 402. Therefore, the lower chuck 421 can move up and down relative to the support member 401 by operation of the lifting mechanism 424, and can move forward and backward in the X direction by the advancing / retreating mechanism 402 moving the lifting mechanism 424.

[0043] When the lower chuck 421 advances to the furthest position on the (+X) side within its 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 edge 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 retreats to the furthest position on the (-X) side within its movable range, the (+X) side tip of the lower chuck 421 retreats to the (-X) side of the edge face of the substrate S. This prevents the lower chuck 421 from coming into contact with the substrate S when it moves up and down.

[0044] In the chuck mechanism 400, the upper chuck 411 and the lower chuck 421 cooperate to grip the substrate S in the plating tank 41. Specifically, the upper chuck 411 and the lower chuck 421 are lowered from the chuck mechanism 400 positioned at the plating position into the plating tank 41 and grip the edge of the substrate S at the same height as the substrate S supported by the transport rollers 21. Therefore, the substrate S is held in the plating tank 41 in a horizontal position with its upper surface flat. The Z direction positions of the upper chuck 411 and the lower chuck 421 at this time will be referred to as the "lower position" hereinafter.

[0045] As shown in Fig. 1 and Fig. 3(b), an anode electrode unit 45 is disposed above the transport path P in the plating tank 41. The anode electrode unit 45 is divided into a plurality of plate-shaped members and includes a plurality of anode electrodes 451, each of which is electrically connected to the power supply unit 7. The anode electrodes 451 are contained in a box-shaped isolation tank 450 with an open top.

[0046] Fig. 5 is a diagram showing a schematic configuration of the main part of the anode electrode unit. The anode electrode 451 has a plurality of electrode plates arranged in a horizontal direction. In the example shown in Fig. 5(a), nine electrode plates 451a to 451i arranged in a 3 x 3 matrix form the anode electrode 451. The lower surfaces of the electrode plates 451a to 451i facing the substrate S are mutually in the same horizontal plane.

[0047] The anode electrode 451 is electrically connected to the power supply unit 7 and receives a supply of electric energy. More specifically, the power supply unit 7 has a plurality of output units 71a-71i that can set output currents independently of one another, and the plurality of electrode plates and the plurality of output units are electrically connected one-to-one, such that the output unit 71a is connected to the electrode plate 451a, and the main power unit 71b is connected to the electrode plate 451b. Each of the output units 71a-71i can be configured, for example, by a DC constant current source, or a DC or pulsating voltage source that can set an upper limit of the output current.

[0048] The output current of each of the output units 71a-71i is determined in response to a control command from the control unit 9. Specifically, the power supply unit 7 is provided with a setting storage unit 72, which stores information related to the current value to be output by each of the output units 71a-71i. Each of the output units 71a-71i outputs a current having a predetermined current value based on the information stored in the setting storage unit 72. The current value of each of the output units 71a-71i stored and saved in the setting storage unit 72 can be changed in response to a control command from the control unit 9 or by a user's operation input.

[0049] The isolation tank 450 includes a frame 452 that laterally surrounds the periphery of the anode electrode 451, and an electrolytic diaphragm 453 that closes the lower part of the frame 452 to form the bottom of the isolation tank 450. The frame 452 is roughly rectangular in plan view, penetrates in the vertical direction, and is made of a material that is resistant to corrosion by the plating solution L, such as a resin material. The electrolytic diaphragm 453 is formed in a flat or sheet shape from a material that blocks non-ionized substances while allowing metal ions to pass through. For example, the electrolytic diaphragm 453 can be made of a porous resin material, an ion exchange resin material, or the like.

[0050] The electrolytic diaphragm 453 closes the lower part of the frame 452 and forms the bottom surface, thereby forming a rectangular box-shaped isolation tank 450 with an open top. The anode electrode 451 is accommodated in the internal space 454 of this isolation tank 450 as shown by the dashed line arrow. To enable this, the frame 452 constituting the isolation tank 450 has an inner wall that is rectangular in shape in a plan view and is slightly larger than the outer size of the anode electrode 451. In addition, in consideration of the convenience of replacement work associated with wear and tear of the electrode material, it is preferable that the anode electrode 451 be detachable from the isolation tank 450.

[0051] As will be described next, the isolation tank 450 housing the anode electrode 451 is immersed in the plating solution L stored in the plating tank 41.

[0052] FIG. 6 is a schematic diagram showing a state in which the isolation tank is immersed in the plating tank. As shown in FIG. 6(a), the isolation tank 450 is arranged so that at least the lower surface of the electrolytic diaphragm 453 forming the bottom surface of the isolation tank 450 is in contact with the plating solution L stored in the plating tank 41. In addition, the second plating solution L2 is poured into the internal space 454 of the isolation tank 450 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, but it can be the same as the plating solution L stored in the plating tank 41, for example. Note that the "same composition" here refers to the composition at the time of supply, and the composition may differ as the treatment progresses. In addition, for example, the type of main component may be the same as that of the first plating solution, and the second plating solution may be substantially the same, but the concentration may be different, or at least one of the presence, absence, type, and content of additives may be partially different. In addition, depending on the purpose, a liquid having a different composition from that of the first plating solution may be used as the second plating solution.

[0053] 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 positioned facing each other with the plating liquid L (+L2) and the electrolytic diaphragm 453 interposed therebetween.

[0054] A predetermined gap G1 larger than zero is provided between the lower surface of the anode electrode 451 and the upper surface of the electrolytic diaphragm 453. A predetermined gap G2 larger 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 calculated using the thickness t of the electrolytic diaphragm 453 as follows: G=G1+G2+t It is expressed by:

[0055] 5 and 6(b), one output terminal of each of the output units 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), the 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.

[0056] Therefore, when an output current of a predetermined magnitude is output from each of the output ports 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 shown by the arrow in FIG. 6(b). An electrochemical reaction caused by the action of this current produces a plating film on the upper surface of the substrate S.

[0057] 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 a uniform composition and thickness, it is desirable to obtain a uniform current density distribution in the surface of the substrate S. However, it is not easy to maintain a uniform current density 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. In the electrolytic plating technique in which an anode electrode faces one main surface of the substrate and a cathode electrode contacts the peripheral portion of the substrate as in this embodiment, current concentration is likely to occur on the peripheral portion of the substrate. For this reason, the film thickness on the peripheral portion tends to be larger than that in the central portion. In particular, when shortening 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 bias of the current.

[0058] To address this problem, for example, there is a technique for alleviating current concentration by covering the periphery of the substrate with a shield plate. However, for a large substrate such as a glass substrate for a display device, a large shield plate is required to cover the periphery, and the size of the shield plate must be optimized according to the substrate size, which increases the cost of the device. Furthermore, there is not enough knowledge about the size and shape of the shield plate that is effective for a rectangular substrate.

[0059] In this embodiment, the anode electrode 451 is divided into a plurality of electrode plates 451a-451i. Output units 71a-71i capable of setting output currents independently of one another are individually connected to the electrode plates 451a-451i. Therefore, by individually adjusting the amount of current supplied to each of the electrode plates 451a-451i, it is possible to change the density distribution of the current flowing from the anode electrode 451 to the substrate S. This makes it possible to improve the uniformity of the plating film by correcting the bias of the current and bringing the current density closer to a uniform distribution.

[0060] As described above, current concentration is likely to occur at the periphery of a rectangular substrate. In view of this, it can be said that, among the electrode plates 451a to 451i, the amount of current tends to be small in the electrode plate 451e facing the center of the substrate S, and large in the other electrode plates arranged to surround it in the horizontal direction. Therefore, it is expected that the current distribution can be made closer to a uniform one by setting the amount of current to the electrode plate 451e arranged in the center to be larger than that to the other electrode plates.

[0061] In addition, because the cathode electrode 412 is held in contact with both ends of the substrate S in the X direction, it is expected that the current will tend to be larger at the ends in the X direction than at the ends in the Y direction. For this reason, it can be said that it is desirable to apply a larger current to the electrode plates 451b and 451h located at both ends in the Y direction in terms of the arrangement of the electrode plates than to the electrode plates 451d and 451f located at both ends in the X direction.

[0062] In this way, the current input to each of the electrode plates 451a-451i can be determined in advance based on the shape and electrode arrangement of the substrate S. In order to more accurately uniformize the current density, a current distribution may be measured by a preliminary experiment, and a set value of the current to be supplied to each of the electrode plates 451a-451i may be determined for each of the output units 71a-71i so as to correct any bias in the current distribution based on the results.

[0063] For the purpose of uniforming the current density near the substrate surface, the current setting value can be optimized, for example, as follows. Here, the value obtained by dividing the current value given to each electrode plate by the area of ​​the lower surface (surface facing the substrate S) of the electrode plate (hereinafter referred to as the "electrode area") is defined as the "electrode current density". If this electrode current density is considered to represent the current density in the portion of the substrate upper surface Sa facing the electrode plate, the output current value to each electrode plate 451a-451i can be determined so that the electrode current density becomes an appropriate current density at each position on the substrate S. In this way, it is possible to appropriately set the output current value to each electrode plate 451a-451i regardless of whether the electrode areas of the electrode plates 451a-451i are the same or different.

[0064] For example, in the case where the current density tends to be high at the periphery of the substrate S and low at the center, as in the above example, the electrode current density is set to be high in the electrode plate 451e arranged at the center and low in the other electrode plates arranged around it, so that the overall current density distribution can be made uniform. In addition, for electrode plates with a part of the lower surface located outside the substrate S in a plan view and not facing the substrate S, the area of ​​the part facing the substrate S may be considered as the effective electrode area. In addition, unless the peripheral part of the electrode plate protrudes outward considerably from the substrate S, the current output from the part that is actually 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 considered as an effective electrode and included in the electrode area.

[0065] The determined setting values ​​are stored in advance as preset values ​​in the setting storage unit 72 of the power supply unit 7, and these can be read out to operate the output units 71a to 71i. The user and the control unit 9 can change these settings as necessary. This makes it possible to deal with cases where it is necessary to change the current distribution, for example, when changing the size of the substrate S.

[0066] It is also possible to use a material having ion permeability not only for the bottom surface but also for the sidewall surface of the isolation tank 450. However, the movement of ions through the sidewall surface can cause current concentration at the periphery of the substrate, impairing the uniformity of the plating film. By allowing ions to move only through the bottom surface of the isolation tank that faces the top surface of the substrate S, such current concentration can be prevented.

[0067] 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 current path shorter than the other portions is formed in that portion, causing current concentration. To avoid this, it is preferable that the cathode electrode 412 contacts the substrate S outside the region of the substrate upper surface Sa that faces the anode electrode 451, more preferably outside the bottom of the isolation tank 450, in a plan view.

[0068] In this sense, it is also effective to construct the frame 452 from a material that is not permeable to ions, and to make the outer size of the isolation tank 450 in a plan view (more precisely, the outer size of the electrolytic diaphragm 453 forming the bottom) smaller than the outer size of the substrate S. In these configurations, ions are prevented from moving through any route other than the electrolytic diaphragm 453, so it can be said that the isolation tank itself fulfills the same function as a blocking plate in the prior art. As shown in FIG. 6(b), these conditions are met in this embodiment.

[0069] In the electrolytic plating process carried out in this manner, a metal soluble in the plating solution L, which is an electrolytic solution, can be used as the anode electrode 451 to form a plating film of the metal on the surface of the substrate S. For the purpose of forming a copper plating film on the substrate S, which is, for example, a glass substrate, it is suitable to use, for example, an aqueous copper sulfate solution as the plating solution L (L2) and, for example, a copper plate as the anode electrode 451.

[0070] When a DC voltage is applied between the anode electrode 451 and the cathode electrode 412 and a current is supplied to the anode electrode 451, a 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. In other words, the anode electrode 451 in this plating reaction is a so-called soluble electrode that contains material that is consumed to form the plating film.

[0071] In this process, the anode electrode 451 gradually dissolves into the plating solution L (L2), and at this time, insoluble impurities contained in the electrode material are liberated into the solution from the anode electrode 451. The insoluble residue thus generated in the plating solution is sometimes called "anode slime" or "anode mud."

[0072] In this embodiment, the substrate S is supported in a horizontal position with the surface to be plated facing upward, and the anode electrode 451 is disposed above the substrate S. As a result, anode slime consisting of impurities liberated from the anode electrode 451 settles in the plating solution toward the substrate S disposed below. If such impurities adhere to the upper surface of the substrate S, which is the surface to be plated, this can cause plating defects and reduce the quality of the plating film.

[0073] To address this problem, in this embodiment, the anode electrode 451 and the substrate S are isolated by an 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 sides of the anode electrode 451 are surrounded by a frame 452. The isolation tank 450 is immersed in the plating solution L in the plating tank 41, and the internal space 454 is filled with a plating solution L2 having the same composition as the plating solution L.

[0074] Therefore, for the metal ions involved in the plating reaction, a path from the anode electrode 451 to the substrate S via the plating solutions L, L2 and the electrolytic diaphragm 453 is secured, while 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 anode slime generated by the aggregation of the insoluble components is blocked by the electrolytic diaphragm 453 and does not adhere to the substrate S.

[0075] In addition, since the box-shaped isolation tank 450 has an opening at its top, the upper part of the anode electrode 451 contained in the isolation tank 450 is open. Therefore, the anode electrode 451 can be easily attached / detached from the isolation tank 450. As the reaction progresses, the anode electrode 451 wears out and must be replaced periodically. The above structure contributes to increasing the convenience of such replacement work.

[0076] The anode electrode 451 is divided into a plurality of electrode plates 451a to 451i. Therefore, the replacement work can be performed for each electrode plate. This improves the workability of the replacement work, and also leads to effective use of resources because only the electrode plate of the anode electrode 451 that needs to be replaced can be replaced.

[0077] The interval between the electrode plates 451a-451i in the horizontal direction can be, for example, smaller than the distance between the lower surface of each electrode plate 451a-451i and the substrate S, and more preferably, can be set to half or less of the distance. If the interval between the electrode plates is large, a sufficient current may not be supplied to the area of ​​the substrate upper surface Sa that does not face any of the electrode plates, causing unevenness in the current density. It is known that the current flowing out from the electrode plate has a certain degree of spread from the outer edge of the electrode plate in the liquid. According to the knowledge of the inventor of the present application in this regard, it is possible to suppress such current unevenness by setting the interval as described above.

[0078] Next, a mechanism for supporting the isolation tank 450 in the anode electrode unit 45 will be described. Due to the structural constraints that the bottom surface of the isolation tank 450 is disposed opposite the substrate S and that 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. In addition, in order to refresh the plating solution L2 and suppress the accumulation 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.

[0079] Fig. 7 is an external perspective view showing a support mechanism for the isolation tank in the anode electrode unit. Note that in Fig. 7, in order to clearly show the structure of the support mechanism, the illustration 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 a support mechanism 460. The support mechanism 460 supports the isolation tank 450 so that it can be moved up and down relative to the plating tank 41 fixed to the frame 10.

[0080] The support mechanism 460 includes support frames 461, 462, and 463 arranged in the vertical direction (Z direction). These support frames are related in such a way that the first support frame 461 arranged at the bottom supports the isolation tank 450, the second support frame 462 arranged above supports the first support frame 461, the third support frame 463 arranged further above supports the second support frame 462, and the third support frame 463 is fixed to the upper frame 11 of the housing 10 (FIGS. 1 and 3(a)).

[0081] Each of the support frames 461 to 463 has a roughly rectangular outer shape and a frame-like structure with a central portion penetrating in the vertical direction. Four sets of lift guide mechanisms 466 whose operating direction is the vertical direction are attached to the third support frame 463 at the top of the frames. Specifically, linear bushes 466a of the lift guide mechanisms 466 are provided at the four corners of the support frame 463. The linear bushes 466a are hollow cylindrical members penetrating in the vertical direction, and a movable rod 466b is inserted into the hollow portion. The movable rod 466b extends downward from the linear bushes 466a, and its lower end is connected to the second support frame 462 below.

[0082] When the lifting mechanism 47, which will be 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 connected 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.

[0083] Similarly, four sets of lift guide mechanisms 465, each of which operates in the up-down direction, are attached to the second support frame 462. Specifically, bushes 465a of the lift guide mechanisms 465 are provided at the four corners of the support frame 462, and movable rods 465b are inserted into the linear bushes 465a. The movable rods 465b extend downward from the linear bushes 465a, and their lower ends are connected to the first support frame 461 below.

[0084] 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 connected 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.

[0085] In this way, the lift guide mechanisms 465, 466 can move the isolation tank 450 in the up and down direction in cooperation with the lift guide mechanism 47. As the lift guide mechanisms 465, 466, various mechanisms other than the combination of the cylindrical linear bush and the movable rod described above can be applied. For example, various mechanisms that can restrict the movement of the object in one direction can be used, such as a linear guide mechanism that combines a guide rail and a slider. Note that the lift guide mechanisms 465, 466 may be provided with a damper function, similar to the lift guide mechanism 464 described next.

[0086] Meanwhile, the first support frame 461 supports the isolation tank 450 so that it can move up and down and tilt around the X-axis. Specifically, four sets of lifting guide mechanisms 464 are attached to the first support frame 461, and movable rods 464b extend downward from linear bushes 464a of the lifting guide mechanisms 464. As described below, the lifting guide mechanisms 464 have a damper mechanism, which reduces the impact transmitted to the isolation tank 450 when the isolation tank 450 is lifted or lowered.

[0087] Further, a frame 455, which is a combination of a plate member 455a extending in the X direction and a plate member 455b extending in the Y direction, is attached to the upper part of the frame 452 constituting the isolation tank 450, and hinge members 455c are attached to four points on the upper part of the frame 455. The lower ends of the movable rods 464b extending from the four lift guide mechanisms 464 are engaged with the hinge members 455c located directly below them, and are attached so as to be rotatable around an axis parallel to the X axis. In this manner, the isolation tank 450 is supported by the support frame 461 via the support mechanism 460.

[0088] In addition, between the two hinge members 455c, 455c arranged on the (-Y) side among the four hinge members 455c, a roller member 455f rotatably supported by an appropriate support member is provided. The roller member 455f is not connected to a drive mechanism and can rotate freely. The function of the roller member 455f will be described later.

[0089] Moreover, equipment for supplying and discharging plating solution L2 to and from the isolation tank 450 is disposed around the isolation tank 450. That is, a nozzle 491 for discharging the plating solution sent from the plating solution supply and discharge part 49 toward the internal space 454 of the isolation tank 450 is provided above the isolation tank 450. The nozzle 491 is attached to the frame 455 via an appropriate fixing member.

[0090] Plating solution supply / discharge unit 49 and nozzle 491 are connected by piping 492 to form a supply path for the plating solution, and flexible joint 493 is provided in piping 492 at a position close to isolation tank 450. A flexible joint is a piping component in which at least a portion of the piping is made of a flexible material such as rubber, and is inserted into a portion of a piping system mainly made of non-flexible tubing material to allow the piping to bend at the insertion point. Flexible joints are widely used, for example, for the purpose of absorbing mutual positional deviations and vibrations at the connection points between pipes.

[0091] As 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 a flexible joint 493 into the pipe 492, it is possible to form a supply path for the plating solution between the plating solution supply / discharge part 49 and the nozzle 491 while allowing such rotation.

[0092] The isolation tank 450 is also provided with a pipe for discharging the plating solution stored in the internal space 454 to the plating solution supply / discharge unit 49. Specifically, a through hole 452a is provided in the lower part of the side surface on the (+Y) side of the frame 452 constituting the isolation tank 450, and a discharge pipe 494 is connected to this through hole 452a. As with the plating solution supply pipe 492, a flexible joint 495 is also inserted into the discharge pipe 494.

[0093] Furthermore, above the anode electrode unit 45, a lifting mechanism 47 fixed to the frame 11 of the housing 10 is provided. For the purpose of explaining the principle, the lifting mechanism 47 is assumed to be a winch mechanism that lifts and lowers an object by winding up a wire. That is, a wire 471 hangs downward from the lifting mechanism 47, and the wire 471 reaches a position directly above the isolation tank 450 through openings in the center of each of the support frames 461 to 463. The lower end of the wire 471 is attached to a connecting portion 455d provided on the frame 455. The connecting portion 455d provided on the frame 455 is disposed at a position closer to the (-Y) side than the middle position between the two hinge members 455c, 455c arranged in the Y direction.

[0094] The lifting mechanism 47 operates in response to a control command from the control unit 9, and moves the isolation tank 450 up and down together with the frame 455 connected to the wire 471. Such up and down movement of the isolation tank 450 can be achieved using various drive mechanisms other than those described above. For example, a known linear motion mechanism such as a ball screw mechanism, an air cylinder mechanism, or a linear motor mechanism, or a device commercially available as a Zip Chain Actuator (registered trademark) can be suitably applied.

[0095] Fig. 8 is a diagram showing a schematic diagram of the supply and discharge of plating solution to and from the isolation tank. Although simplified in Fig. 7, as shown in Fig. 8(a), the lift guide mechanism 464 includes a linear bush (also called a linear bearing or linear bearing) 464a into 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.

[0096] The movable rod 464b is inserted into the linear bushing 464a so as to be movable up and down. When the movable rod 464b moves up and down, the bracket 464d also moves up and down accordingly. When the bracket 464d descends, it comes into contact with the damper mechanism 464e, and further downward displacement is restricted. In other words, the damper mechanism 464e has a function of allowing the movable rod 464b to move up and down, while regulating its movable range, and also mitigating the impact when the descent stops.

[0097] Two sets of lift guide mechanisms 464 are provided at different positions in the Y direction. The lower ends of movable rods 464b of each lift guide mechanism 464 are engaged with hinge members 455c attached to the frame 455 of the isolation tank 450. As a result, the isolation tank 450 is supported in a substantially horizontal position in a steady state.

[0098] With the isolation tank 450 supported in a substantially horizontal position in this manner, as shown by the outlined arrow in Fig. 8(a), the plating solution L2 is supplied to the isolation tank 450 from the plating solution supply / discharge unit 49 through the piping 491. The plating solution L2 is discharged from a 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. With the anode electrode 451 immersed in the plating solution L2, a plating process is performed.

[0099] After the plating process is completed, the plating solution L2 in the internal space 454 can be refreshed by discharging the existing plating solution and refilling it with 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 because the substrate S is placed directly below the isolation tank 450.

[0100] It is also possible to flow the plating solution L2 from the isolation tank 450 into the plating tank 41 and discharge the plating solution L2 through the plating tank 41. However, doing so would result in the anode slime contained in the plating solution L2 being mixed into the plating tank 41, so it is preferable to discharge the plating solution L2 through a route independent of the discharge from the plating tank 41.

[0101] For the same reason, when supplying plating solution to isolation tank 450 and when tilting isolation tank 450 to promote drainage, as described below, it is necessary to prevent plating solution L2 from overflowing from isolation tank 450 and flowing into plating tank 41.

[0102] In order to discharge the plating solution while satisfying these requirements, a discharge port is provided on the side wall of the isolation tank 450 to discharge the plating solution to the side, but this inevitably impairs the smoothness of discharge compared to when a discharge port is provided on the bottom surface. Therefore, in this embodiment, a through hole 452a is provided as a discharge port on the (+Y) side surface of the isolation tank 450, and a discharge pipe 494 is connected to the through hole 452a. When discharging the plating solution L2, the isolation tank 450 is lifted on the side opposite to the discharge port, i.e., the (-Y) side, to incline the bottom surface. This can promote the discharge of the plating solution L2 from the internal space 454.

[0103] Specifically, by winding up wire 471, lifting mechanism 47 can pull up frame 455 and lift the (-Y) side end of isolation tank 450, as shown by the dashed arrow in Fig. 8(b). In this way, isolation tank 450 is inclined with its bottom surface inclined relative to the horizontal plane, so that plating solution L2 stored in internal space 454 flows toward through hole 452a, which serves as a discharge port, as shown by the hollow arrow in Fig. 8(b). In this way, discharge of plating solution L2 is promoted. Waste liquid that has flowed into piping 494 is collected by plating solution supply and discharge unit 49.

[0104] The manner in which the isolation tank 450 is supported by the lift guide mechanism 464 connected via the rotatable hinge member 455c allows such tilting of the isolation tank 450. That is, in a pair of lift guide mechanisms 464, 464 disposed at different positions in the Y direction, the movable rods 464b move up and down independently of each other, thereby realizing a tilted state of the isolation tank 450.

[0105] Moreover, flexible joints 493, 495 are inserted in a plating solution supply pipe 492 and a discharge pipe 494 connected to the isolation tank 450. Therefore, the isolation tank 450 can be tilted with these pipes still connected.

[0106] Although the description so far has been omitted in order to explain the overall configuration and basic operation of the apparatus, the plating apparatus 1 is provided with a mechanism for supplying liquid to a gap space between the anode electrode 451 and the substrate S, more precisely, between the lower surface of the electrolytic diaphragm 453 forming the bottom surface of the isolation tank 450 and the upper surface (one main surface) Sa of the substrate S. In this embodiment, the anode electrode 451 (more precisely, the isolation tank 450 containing the anode electrode 451) is disposed above the large substrate S, and a narrow gap space is formed between them, and the gap space is filled with the plating solution L.

[0107] In such a configuration, the plating solution L tends to remain in the gap space, and the composition may change as the plating reaction progresses. This is because the substances consumed in the plating reaction are not replenished, and the by-products produced in the reaction are not discharged. This can cause unevenness in the thickness and quality of the plating film, so it is desirable to refresh the liquid filling the gap space at least during the current application period. The liquid supply mechanism provided in this embodiment to make this possible will be described below.

[0108] 9 is a diagram showing two modes of the liquid supply mechanism. Either of these mechanisms supplies liquid toward the gap space GS between the substrate S and an isolation tank 450 disposed above the substrate S, thereby refreshing the plating solution filling the gap space GS.

[0109] In a first embodiment shown in Fig. 9(a), a liquid supply mechanism 61 is provided in the gap space GS. Although details will be described later, in the liquid supply mechanism 61, pipes 611 through which liquid is conveyed are arranged two-dimensionally along the bottom surface of the isolation tank 450, and outlets 612 that function as liquid outlet nozzles are provided on the bottom surface of the pipes 611. That is, in this embodiment, liquid is ejected downward from the upper part of the gap space GS, as shown by the outlined arrow in Fig. 9(a).

[0110] On the other hand, in a second embodiment shown in Fig. 9(b), a liquid supply mechanism 62 is provided outside the gap space GS, more specifically, on both sides of the gap space GS in the X direction. In the liquid supply mechanism 62, a liquid discharge nozzle 621 through which liquid is delivered extends in the Y direction. A discharge port 622 is provided on the side of the liquid discharge nozzle 621 facing the gap space GS. That is, in this embodiment, liquid is discharged laterally from the side of the gap space GS, as shown by the outline arrow in Fig. 9(b).

[0111] In these embodiments, the liquid discharged from the liquid supply mechanisms 61, 62 has the effect of stirring and flowing the liquid filling the gap space GS, and has the effect of eliminating stagnation of the plating solution L in the gap space GS. In particular, when the liquid contains a substance that contributes to the plating reaction, a more active effect can be expected. For example, if the discharged liquid has the same composition as the plating solution L stored in the plating tank 41, the gap space GS is always filled with fresh plating solution during the plating process, which is extremely effective in uniforming the thickness and film quality of the plating film.

[0112] Furthermore, even if the composition is not completely the same, it can be said to be substantially the same, for example, if the type of main component is the same as that of plating solution L, but the concentration of the main component is different, or at least one of the presence, type, or content of additives is partially different, may be used.

[0113] Also, for example, if a liquid containing a component whose content in the liquid changes with the progress of the plating reaction is used, it is possible to replenish the component that decreases in the liquid. For example, if the metal material consumed in the formation of the plating film is contained in the liquid in the form of ions, it is possible to suppress the decrease in the component and stably form the plating film. For example, in the case of a process for forming a copper thin film on a glass substrate, a liquid containing at least copper ions can be suitably used. Naturally, the plating solution L also meets this requirement. In the following, a liquid having the same composition as the plating solution L is used.

[0114] The structure of each embodiment will be described in detail below, but only one or both of these liquid supply mechanisms 61, 62 may be provided in one plating apparatus 1. When two liquid supply mechanisms 61, 62 are provided in one apparatus, they may be selectively operated, or the two liquid supply mechanisms 61, 62 may be configured to operate in one process.

[0115] Figure 10 shows a first embodiment of the liquid supply mechanism. Figure 10(a) is a perspective view of liquid supply mechanism 61 as viewed from below, and Figure 10(b) is a bottom view. Figure 11 shows the piping system in the first embodiment of the liquid supply mechanism.

[0116] 10(a), the liquid supply mechanism 61 includes a plurality of pipes 611 (611a to 611j) arranged two-dimensionally along the bottom surface of the isolation tank 450. These pipes 611a to 611j are attached to the frame 452 of the isolation tank 450 by appropriate fixing members (not shown). The plurality of pipes 611a to 611j are not connected to each other and are independent of each other. Therefore, liquid is supplied individually to each of the pipes 611a to 611j.

[0117] 11, each of the pipes 611a to 611j is connected to the plating solution supply / discharge unit 49, and a control valve 613a to 613j corresponding to each of the pipes 611a to 611j is inserted in the path. Each of the control valves 613a to 613j operates independently in response to a control command from the control unit 9, thereby enabling the supply of liquid to each of the pipes 611a to 611j to be turned on and off and the supply amount to be adjusted.

[0118] A plurality of discharge ports 612 are provided on the bottom surface of each of the pipes 611a to 611j, and the liquid supplied to each of the pipes 611a to 611j is discharged downward from the discharge ports 612. In this manner, the liquid is supplied to the gap space GS, particularly to the space close to the upper surface Sa of the substrate S. If the liquid has a composition similar to that of the plating liquid L, fresh plating liquid will always be supplied.

[0119] 12A and 12B are diagrams showing the effect of liquid supply. As shown by the dotted lines in FIG. 12A, when liquid is discharged from a plurality of discharge ports 612 provided above the substrate S, a flow of plating liquid occurs above the substrate S as shown by the arrows. This makes it possible to eliminate stagnation of plating liquid in the gap space GS, particularly in a position close to the substrate S. As described above, by appropriately setting the composition of the liquid, it is possible to replenish components that are reduced in the plating reaction.

[0120] Since the pipes 611 (611a to 611j) are disposed between the anode electrode 451 and the substrate S, there is a concern that the pipes 611 (611a to 611j) may block the path of the current flowing from the anode electrode 451 to the substrate S. This problem can be addressed as follows. In such an electrolytic plating reaction, it has been found that, as shown by the dotted line in FIG. 12(b), the current flowing from one point on the anode electrode 451 spreads to a certain extent and spreads toward the substrate S. The width of the pipes 611 and their horizontal and vertical arrangements may be determined according to the set value θ by appropriately setting a predetermined spread angle θ so that all positions on the substrate S are included within the above-mentioned predetermined spread angle range when viewed from at least one position, preferably multiple positions, of the anode electrode 451. In this way, the influence of shielding by the pipes can be avoided.

[0121] Furthermore, if the pipe 611 is a conductor, it may affect the electric field distribution in the gap space GS, which may cause bias in the current density distribution. To avoid this, it is preferable that the pipe 611 is an insulator. From the viewpoint of corrosion resistance against the plating solution L, it is preferable that the pipe 611 is made of a resin material having excellent chemical resistance.

[0122] 10(b), the pipes 611a-611j are arranged so that the pipes 611e-611h surround the pipes 611i, 611j provided in the center, and the pipes 611a-611g surround the pipes 611e-611h on the outermost side. The timing and amount of liquid supplied to these pipes 611a-611j can be individually controlled.

[0123] 10(b), consider an area that, in plan view, continuously covers all of the outlets 612 provided in one pipe 611. Here, such a virtual area is referred to as a "corresponding area" in the sense of the range affected by the liquid supplied from that pipe, and the corresponding areas corresponding to the pipes 611a to 611j, respectively, are represented by symbols Ra to Rj.

[0124] When "corresponding regions" are defined in this way, it is possible to define one corresponding region without intersecting with any other corresponding regions and without being divided by other regions. In other words, the piping pattern is set in advance to achieve such a relationship. By using such a piping pattern, the following effects can be obtained.

[0125] That is, in the above-described configuration in which multiple discharge ports 612 are provided in one pipe 611, the discharge amount from each discharge port 612 cannot be adjusted individually, and the discharge amount is adjusted for each pipe. For this reason, if the liquid supply from the pipe to be controlled and the liquid supply from another adjacent pipe interfere with each other, the liquid supply amount at each position in the gap space GS may not follow a desired pattern.

[0126] In the above piping pattern, an area (corresponding area Ri) to which liquid is supplied from one pipe, for example, the outlet 612 connected to the pipe 612i, and an area (corresponding area Re) to which liquid is supplied from another pipe, for example, the outlet 612 connected to the pipe 612e, can be separated, so that interference between them can be avoided. This makes it possible to accurately control the amount of liquid supplied to each position.

[0127] With this configuration, it is possible not only to uniformly discharge the liquid from each of the pipes 611a to 611j, but also to increase or decrease the amount of liquid supplied to a specific portion as necessary. For example, since the accumulation of plating liquid is most noticeable in the center portion of the substrate S, it is possible to effectively eliminate the accumulation by supplying a larger amount of liquid to the center portion than to other portions.

[0128] In this embodiment, as shown in Fig. 4(b), the cathode electrode 412 abuts against both ends of the lower surface Sb of the substrate S in the Y direction. For this reason, current concentration is likely to occur near the cathode electrode 412, which may result in a local increase in the thickness of the plating film. In this embodiment, this problem can be addressed by dividing the anode electrode 451 into multiple parts and adjusting the current distribution among them. Alternatively or in addition to this, the same effect can be expected by locally varying the amount of liquid supplied to the gap space GS as described above and adjusting the ion concentration distribution in the liquid.

[0129] Fig. 13 is a diagram showing a second embodiment of the liquid supply mechanism. As shown in Fig. 12(a), in this liquid supply mechanism 62, liquid discharge nozzles 621 are provided on both sides of the substrate S in the X direction in the plating tank 41. In this example, three liquid discharge nozzles 621 are arranged in the Y direction on each side so as to sandwich the substrate S in the X direction. However, the number of liquid discharge nozzles 621 to be arranged is arbitrary. As shown in Fig. 9(b), the liquid discharge nozzles 621 are arranged in a position close to the upper surface of the substrate S, and therefore may become an obstacle when the substrate S is inserted into or removed from the plating tank 41.

[0130] Since the transport direction Dt (FIG. 1) of the substrate S is the Y direction, the liquid discharge nozzle 621 may be provided on the outside of both ends in the X direction of the substrate S. This makes it possible to dispose the liquid discharge nozzle 621 close to the substrate S without impeding the transport of the substrate S.

[0131] In order to distinguish the six liquid discharge nozzles 621 from one another, they are denoted by reference numerals 621a to 621f, as shown in Fig. 13(a). Each liquid discharge nozzle 621 is connected to the plating liquid supply / discharge unit 49, and a control valve 623a to 623f corresponding to each liquid discharge nozzle 621a to 621f is inserted on the path. Each control valve 623a to 623f operates independently in response to a control command from the control unit 9, thereby enabling the supply of liquid to each liquid discharge nozzle 621a to 621f to be turned on and off and the supply amount to each liquid discharge nozzle 621a to 621f to be adjusted.

[0132] In order to send liquid from the outside of the gap space GS to the inside thereof, and in particular to have the liquid reach the center, the liquid needs to be discharged at a relatively high speed and with a large flow rate. To make this possible, the liquid discharge nozzle 621 has the following structure. That is, as shown in Fig. 13(b), the liquid discharge nozzle 621 has a manifold space 624 inside, and the multiple discharge ports 622 provided on the side of the liquid discharge nozzle 621 each communicate with this manifold space 624.

[0133] A liquid supply port 625 communicating with a manifold space 624 is provided on the side surface of the liquid discharge nozzle 621 opposite to the discharge port 622, and the opening area of ​​the liquid supply port 625 is sufficiently larger than the opening area of ​​the discharge port 622. In addition, a plurality of liquid supply ports 625 may be provided as necessary. A liquid, specifically a plating solution, is supplied to the liquid supply port 625 from the plating solution supply / discharge unit 49.

[0134] The liquid supplied to the manifold space 624 via the relatively large opening of the liquid supply port 625 is discharged horizontally at high speed from the smaller opening of the discharge port 622. By supplying a sufficient amount of liquid to the liquid supply port 625, the objective of discharging the liquid at high speed and at a large flow rate toward the gap space GS is achieved.

[0135] In a mode in which liquid is fed into the gap space GS from both sides of the gap space GS in the X direction, it is considered that the flow of liquid is difficult to occur in the center of the gap space GS. This problem can be solved by individually controlling the supply timing and supply amount of liquid to each of the multiple liquid discharge nozzles 621a to 621f.

[0136] That is, by varying the timing and amount of liquid discharged from each of the liquid discharge nozzles 621a to 621f, it is possible to generate a complex flow of plating liquid in the gap space GS. In particular, by changing the amount of liquid discharged from each of the liquid discharge nozzles 621a to 621f over time, a more complex flow can be generated, which is more effective in eliminating stagnation.

[0137] Fig. 14 is a block diagram showing the electrical configuration of this plating apparatus. In the plating apparatus 1 configured as above, the control unit 9 controls each unit of the apparatus to cause the plating apparatus 1 to perform a predetermined process. The hardware configuration of the control unit 9 can be the same as that of a general computer device, for example. That is, the control unit 9 can be equipped with a CPU (Central Processing Unit) 91, memory 92, storage 93, input unit 94, display unit 95, interface unit 96, etc.

[0138] The memory 92 temporarily stores various data generated during the process. The storage 93 long-term stores various data and a control program 931. The input unit 94 and the display unit 95 perform a user interface function. The interface unit 96 performs communication with external devices and the like.

[0139] The CPU 91 reads out and executes a control program 931 stored in advance in the storage 93, and controls each part of the apparatus based on the control program to perform a predetermined operation, thereby implementing various operations described below. For this purpose, the CPU 91 realizes, in software, functional blocks such as a transfer control unit 911 that controls the operation of the transfer unit 2, a chuck control unit 912 that controls the operation of the chuck unit 40, a supply and discharge control unit 913 that controls the supply sources of various fluids to manage their supply and discharge, a flow rate control unit 914 that controls valves on the piping to adjust the flow rate of the circulating fluid, and a power supply control unit 915 that controls the power supply to the electrodes by the power supply unit 7. At least some of these functional blocks may be configured as dedicated hardware, for example.

[0140] In addition, the specification and drawings of Patent Application No. 2022-094449 previously disclosed by the applicant of the present application disclose a plating apparatus having a basic configuration similar to that of the plating apparatus 1 of this embodiment, and include detailed descriptions of the structure and functions of each part of the apparatus, as well as the operation of the apparatus.

[0141] Next, the operation of the plating apparatus 1 configured as described above will be described. The basic operational flow of the plating apparatus 1 is roughly as follows. An unprocessed substrate S is carried into the carry-in section 3. The substrate S is transported from the carry-in section 3 to the plating section 4, which performs electrolytic plating on the substrate S to form a metal coating on its surface (upper surface Sa). The plated substrate S is rinsed in the rinsing section 5 and is finally carried out to the unloading section 6.

[0142] FIG. 15 is a flow chart showing the plating process. FIG. 16 is a diagram showing the operation of each part. More specifically, FIG. 16 shows the operation of each part as time T progresses, with the time axis being from top to bottom. After an unprocessed substrate S is provided to the loading part 3 at time T0, each part of the apparatus performs the following operations. In the figure, the parentheses indicate the initial state of each part. In FIG. 16, the parts of each processing part shown with thick vertical lines indicate that the substrate S is present in that processing part.

[0143] Each part of the plating apparatus 1 is set in advance to a predetermined initial state. In the initial state, the chuck mechanism 400 is positioned at a plating position above the plating tank 41, and the upper chuck 411 and the lower chuck 421 are positioned at upper positions that do not interfere with the plating tank 41. Note that the upper chuck 411 and the lower chuck 421 may be positioned lower as long as they do not impede the transport of the substrate S along the transport path P.

[0144] In the loading section 3, the loaded substrate S is temporarily stored. In the plating processing section 4, the shutters 41a and 41b of the plating tank 41 are opened, allowing the substrate S to be transported along the transport path P. At this time, the plating tank 41 is stored to a height such that the plating solution supplied from the plating solution supply / discharge section 49 does not flow out of the opening. In the anode electrode unit 45, the isolation tank 450 is retracted upward, and no plating solution is stored in the internal space 454. In the rinsing processing section 5, the shutters 51a and 51b of the rinsing tank 51 are also opened, allowing the substrate S to be transported along the transport path P. At this time, the substrate S is not present in the unloading section 6.

[0145] At time T1, the transport unit 2 starts transporting the substrate S, and the substrate S is transported in the transport direction Dt (+Y direction) along the transport path P, and is finally transported to the plating tank 41 (step S101). In Fig. 15, the dashed arrow indicates the transfer of the substrate S by the transport unit 2.

[0146] When the substrate S is carried 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 are lowered toward the substrate S accommodated in the plating tank 41 to grip the substrate S (step S102). In the anode electrode unit 45, the isolation tank 450 is lowered and disposed to face the upper surface of the substrate S held in the plating tank 41. Note that the substrate S may be transported to the plating tank 41 with the isolation tank 450 already lowered.

[0147] 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, a state is realized in which 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 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)).

[0148] Then, a predetermined current is output from each output portion 71a of the power supply 7 (step S104), whereby the substrate S is plated. By contacting the cathode electrodes extending long in the Y direction with both ends in the X direction of the upper surface Sa of the substrate S, the variation in current density on the upper surface Sa of the substrate S is suppressed, and it becomes possible to form a plating film with good uniformity.

[0149] At this time, the chuck mechanism 400 and the transport rollers 21 work together to oscillate the substrate S in the plating tank 41 (step S105), thereby further improving the uniformity of the plating film. Specifically, the movement mechanism 43 is actuated to cause the support frame 430 supporting the chuck mechanism 400 to alternately move in the (+Dt) direction and the (-Dt) direction. As a result, the chuck mechanism 400 attached to the support frame 430 moves back and forth integrally in the Y direction, and the substrate S held by the chuck mechanism 400 oscillates in the Y direction in the plating solution L.

[0150] At this time, the transport rollers 21 work in conjunction 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 transport rollers 21 rotate in the forward direction, that is, in the direction 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 transport rollers 21 rotate in the reverse direction, that is, to transport the substrate S in the direction (-Dt) opposite to the transport direction Dt.

[0151] By rocking the substrate S in the plating solution L in this manner, the plating solution L is stirred, reducing bias in the ion concentration in the solution and improving the uniformity of the plating film. The rocking of the substrate S in the plating tank 41 is achieved by the cooperation of a chuck mechanism 400 that grips the edge of the substrate S and a transport roller 21 that supports the center of the substrate S from the underside. This makes it possible to prevent local stress from being applied to the substrate S and to rock the substrate S while maintaining a horizontal position.

[0152] During at least a part of the energizing period, and preferably during the entire period, liquid is supplied from the liquid supply units 61, 62. This further promotes the flow of the plating solution in the gap space GS and replenishes necessary components, enabling the plating process to be carried out satisfactorily.

[0153] After the substrate S is immersed in the plating solution L and the state in which the substrate S is oscillated while a current is supplied between the electrodes is continued for a certain period of time, the current supply is stopped (step S106), thereby stopping the plating process. 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, the lifting mechanism 47 is operated to lift the (-Y) side end of the isolation tank 450 while the isolation tank 450 is retracted upward by the support mechanism 460.

[0154] Then, the substrate S is released from the chuck mechanism 400 (step S108), the shutter 41b is opened, and the transport unit 2 transfers the substrate S from the plating unit 4 to the rinsing unit 5 at time T2 (step S109). By releasing the substrate S from the plating unit after the plating solution L is discharged, it is possible to prevent the cathode electrode 412 from coming into contact with the plating solution. There is no such restriction for the anode electrode 451. Therefore, the discharge from the isolation tank 450 can be performed at any timing after the current is stopped. In other words, it is not necessary to be performed simultaneously with the discharge of the plating solution L from the plating tank 41.

[0155] In the rinsing processing unit 5, when the substrate S is accommodated in the rinsing tank 51, the shutters 51a and 51b are closed, and a rinsing liquid is supplied from the rinsing liquid supply / discharge unit 59 to rinse the substrate S (step S110). After the rinsing process is performed for a predetermined time, the supply of the rinsing liquid is stopped, the shutter 51b is opened, and at time T3, the substrate S is discharged to the unloading unit 6 (step S111).

[0156] When discharging the plating solution from the plating tank 41, it is not necessary to completely drain the liquid in the tank. In other words, as long as the liquid is discharged to the extent that the substrate S supported in the tank is exposed from the liquid and can be removed, there is no problem with the liquid remaining in the tank. In fact, by leaving the liquid remaining, it is possible to reduce the amount of liquid required to fill the tank when processing the next substrate S. This contributes to reducing the consumption of liquid and the environmental load.

[0157] Meanwhile, after releasing the grip of the substrate S, the chuck mechanism 400 undergoes a cleaning process to remove the plating solution adhering to the upper chuck 411 and the lower chuck 421 (step S112). The cleaning process may be carried out in any manner, but an example thereof 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 a 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 supplying an appropriate cleaning liquid or injecting air.

[0158] When the chuck mechanism 400 moves between the plating position and the cleaning position, the upper chuck 411 and the lower chuck 421 are retracted upward by the lifting mechanisms 412, 422, as shown by the dotted lines in Fig. 2. This prevents the upper chuck 411 and the lower chuck 421 from contacting 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 will be referred to as the "upper position" hereinafter.

[0159] After cleaning, the chuck mechanism 400 is returned to the plating position (step S113). By cleaning the chuck mechanism 400 in this manner, it is possible to prevent the remaining plating solution from adhering to the substrate S when processing the next substrate S. If there is another substrate S to be processed, the process returns to step S101 and the above processing is repeated.

[0160] As described above, in the plating apparatus of this embodiment, the substrate S, which is the object of plating, is supported in the plating tank 41 in a horizontal position with one main surface Sa, which is the surface to be plated, facing upward, that is, in a so-called face-up state. The cathode electrode 412 contacts the peripheral portion of the substrate S, and the anode electrode 451 is disposed opposite the upper surface of the substrate S.

[0161] However, the anode electrode 451 and the substrate S are separated by an electrolytic diaphragm 453. This ensures a path between the anode electrode 451 and the substrate S for metal ions that are the material of the plating film, while isolating the anode electrode 451 and the substrate S for non-soluble components and liquid components. This prevents anode slime generated by substances liberated from the anode electrode 451 from adhering to the substrate S and degrading the quality of the plating film.

[0162] The anode electrode 451 is divided into a plurality of electrode plates 451a-451i, and output units 71a-71i, which are constant current sources of the power supply unit 7, are individually connected to the respective electrode plates. The output current from each of the output units 71a-71i can be individually set. Therefore, even if the substrate S is large, it is possible to suppress unevenness in the current density distribution within the surface of the substrate S and to achieve a uniform thickness of the plating film.

[0163] Furthermore, with regard to replacement of the plating solution in the isolation tank 450, since the bottom surface of the isolation tank 450 is disposed opposite the substrate S, it is difficult to provide a mechanism for draining the solution below the isolation tank 450. Therefore, in this embodiment, a drain outlet is provided on the side wall surface of the isolation tank 450. Furthermore, in order to efficiently drain the solution, a mechanism for lifting the end of the isolation tank 450 and tilting the bottom surface is provided on the side opposite to the side wall surface on which the drain outlet is provided. This promotes drainage of the plating solution.

[0164] That is, the isolation tank 450 of this embodiment can be switched between a horizontal position where the bottom surface is horizontal and an inclined position where the bottom surface is significantly inclined with respect to the horizontal plane. In the horizontal position, the anode electrode 451 can be placed opposite the substrate S for plating, while in the inclined position, the plating solution remaining in the internal space 454 of the isolation tank 451 can be efficiently discharged and new plating solution can be received thereafter, thereby keeping the plating solution stored in the internal space 454 fresh.

[0165] In this embodiment, liquid supply mechanisms 61, 62 are provided above the substrate S to supply liquid to the gap space GS between the substrate S and the anode electrode 451. Supplying liquid from these mechanisms to the gap space GS promotes the flow of liquid in the gap space GS, eliminating stagnation of the plating solution. If a liquid containing a substance that decreases due to a plating reaction is used, the plating process can be continued stably while replenishing such a substance.

[0166] <Modification> FIG. 17 is a diagram showing a modified 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 for dividing the anode electrode into a plurality of parts is not limited to this, and various patterns are possible. For example, in the anode electrode 456 shown in FIG. 17(a), electrode plates having substantially the same shape are arranged in a 5×4 matrix. In this way, the number of electrode plates arranged is not limited to that in the above embodiment, and can be any number.

[0167] 17(b), a large-area electrode plate is arranged in the center where a relatively uniform current density can be obtained, while the area of ​​the electrode plate is made smaller in the peripheral and corner areas where bias in the current density is likely to occur, making it easier to fine-tune the current density distribution. In this way, the shape and size of each electrode plate can be appropriately determined according to the purpose.

[0168] 17(c) has a structure in which a rectangular electrode plate arranged in the center is surrounded by multiple frame-shaped electrode plates with a rectangular outline and an opening in the center. With such a structure, it is possible to achieve the object of setting the current density independently in the center and the periphery of the substrate S.

[0169] Thus, various division patterns of the anode electrode are possible. When setting the division pattern and distributing the current to each electrode plate, for example, a method can be adopted in which the current density distribution is actually measured by a preliminary experiment and the current is determined based on the results. Specifically, in an area of ​​the substrate surface where the current density fluctuation is small, there is little need to finely divide the opposing electrode plate, and conversely, in an area where the current density fluctuation is large, finely dividing the electrode plate makes it easier to adjust the current density distribution. In addition, the current setting value can be reduced in areas where the current density is higher, thereby making the current density uniform.

[0170] In particular, when two opposing sides of the four sides of a rectangular substrate are chucked, the cathode electrodes are placed near these two sides, so it is expected that the current distribution will be significantly different from the two sides that are not held. Even in such a case, it is possible to suppress bias in the current density distribution and improve the uniformity of the plating film by adjusting the division pattern of the anode electrode and the current value supplied to each electrode plate.

[0171] Although the division pattern of the anode electrode for adjusting the current density distribution in the gap space GS has been described here, the same can be said for the arrangement pattern of the pipes 611 in the liquid supply mechanism 61. That is, as described above, the pipes 611 divided into a plurality of parts in the liquid supply mechanism 61 of this embodiment adjust the ion concentration distribution in the liquid by individually controlling the supply timing and supply amount of the liquid, thereby achieving uniformity in the thickness and quality of the plating film.

[0172] Therefore, for the piping 611 in the body supply mechanism 61, various arrangement patterns can be adopted as necessary, similar to the electrode patterns shown in FIGS. 17(a) to (c).

[0173] <Other> 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 "treatment tank", the "holding unit", the "cathode electrode" and the "anode electrode" of the present invention, respectively. In addition, the liquid supply units 61 and 62 each function as the "liquid supply unit" of the present invention.

[0174] Moreover, the pipes 611 (611a to 611i) and the discharge port 612 in the liquid supply unit 61 correspond to the "pipes" and "discharge port" of the present invention, respectively. Moreover, in the liquid supply unit 62, the liquid discharge nozzle 621 corresponds to the "nozzle" of the present invention, and the discharge port 622 corresponds to the "discharge port" of the present invention. Moreover, the control valves 613a to 613i connected to each pipe function as the "supply control unit" of the present invention.

[0175] The present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-mentioned embodiment, the chuck mechanisms 400 are provided for 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 mechanisms.

[0176] Also, for example, in the above embodiment, the chuck mechanism 400 grips the substrate S transported into the plating tank 41 by the transport rollers 21. However, the transport means is not limited to rollers and is optional. On the other hand, a mode in which the substrate is transported while being gripped by the chuck mechanism is also conceivable. In this case, the transport means is not an essential component, but in order to stably maintain the posture of a large substrate, it is desirable to provide some kind of backup means that supports the center of the substrate S from below.

[0177] It should be noted that the substrate to be processed does not necessarily have to be a geometric rectangle in the strict sense of the word. For example, even if one of the sides of the substrate has some irregularities, it is sufficient if the envelope outline can be regarded as being approximately rectangular.

[0178] Furthermore, for example, the power supply unit 7 in the above embodiment includes a constant current output source that individually corresponds to each of the electrode plates that constitute the anode electrode 451. Alternatively, the power supply unit may be configured by, for example, a combination of a single voltage source and a plurality of current limiting elements provided corresponding to each of the electrode plates.

[0179] Also, for example, in the power supply unit 7 of the above 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), it is possible to realize a division pattern substantially the same as that of the anode electrode 457 shown in FIG. 16(b) by connecting some electrode plates in parallel. Also, the connection relationship between the electrode plates and the power supply may be changed as necessary.

[0180] Furthermore, for example, in the above embodiment, the anode electrode 451 is divided into multiple electrode plates, but the effect of preventing adhesion of anode slime to the substrate, which is obtained by isolating the anode electrode and the substrate by an isolation tank, can be similarly obtained in a plating apparatus in which the anode electrode is constituted by a single electrode plate.

[0181] In addition, the retention of plating solution in the gap space GS is also a problem that can occur regardless of whether the anode electrode is divided or not, and whether it is contained in an isolated tank or not. Therefore, the liquid supply units 61, 62 of the above embodiment function effectively even when the anode electrode is a single member that is not divided, or when the anode electrode is not isolated and directly comes into contact with the plating solution in the plating tank.

[0182] In addition, in the above embodiment, the liquid stored in the plating tank 41 and the liquid stored in the isolation tank 451 are plating solutions having the same or substantially the same composition, but the above configuration is effective even when these liquids have different compositions. That is, each liquid can be supplied and discharged independently, and mixing of the two is prevented.

[0183] Furthermore, the anode electrode 451 in the above embodiment is a soluble electrode that contains a metal (e.g., copper) that is the material of the plating film and is consumed as the plating process progresses. However, even in the case of a non-soluble electrode whose electrode material does not directly contribute to the plating reaction, problems such as uneven film thickness and film quality due to bias in current density distribution can occur. For this reason, even in the case of a non-soluble electrode, making it possible to individually adjust the current by using a divided structure as described above is effective in optimizing the current density distribution and achieving uniform film thickness.

[0184] Similarly, in a plating apparatus using non-soluble electrodes, the supply of liquid to the gap space GS by the liquid supply units 61, 62 of the above embodiments is effective in eliminating stagnation of the plating solution in the space and achieving uniform film thickness and quality.

[0185] As described above by way of example of specific embodiments, in the plating apparatus according to the present invention, the liquid supply unit may have a pipe arranged along the lower surface of the anode electrode in the gap space and through which the liquid is delivered, and a discharge port is provided on the lower surface of the pipe. With this configuration, the liquid is discharged from the discharge port that opens downward in the gap space, thereby effectively promoting the flow of the plating liquid in the gap space.

[0186] In this case, the liquid supply unit may have a plurality of pipes each having an outlet and not connected to each other, and a supply control unit that sets the supply amount of liquid to each of the pipes individually. With this configuration, the supply amount of liquid can be individually adjusted at each position in the gap space. This makes it possible to realize an optimal supply mode for making the plating film uniform in thickness and quality.

[0187] Furthermore, when a continuous virtual area including all the outlets provided in one pipe is defined as a corresponding area of ​​the pipe in a plan view, it is preferable that the arrangement of the pipes is set so that the corresponding areas of the multiple pipes can be defined so as not to overlap each other. With this configuration, it is possible to suppress interference between the liquids supplied from the multiple pipes and to adjust the flow of the liquid in the gap space with good controllability.

[0188] For example, the liquid supply unit may be disposed on the side of the gap space outside the substrate in a plan view, and may have a nozzle having a discharge port on a side surface facing the gap space for discharging the liquid. With such a configuration, the liquid discharged from the side of the gap space toward the gap space can promote the flow of the plating solution in the gap space.

[0189] In this case, for example, a pair of nozzles may be provided on either side of the gap space, and by using such a configuration, the flow of the plating solution in the gap space can be effectively promoted and the stagnation of the plating solution can be eliminated by feeding the liquid from both sides of the gap space.

[0190] For example, an electrolytic diaphragm may be provided between the anode electrode and one of the main surfaces, and in this case, the gap space is the space sandwiched between the electrolytic diaphragm and one of the main surfaces. For example, in order to prevent insoluble impurities generated in the plating solution by the plating reaction from dropping onto the substrate, an electrolytic diaphragm that does not allow such impurities to pass but allows ions to pass may be provided between the anode electrode and the substrate. In such a configuration, the space directly above the substrate, i.e., the space sandwiched between the electrolytic diaphragm and one of the main surfaces of the substrate, can be regarded as the gap space, and the present invention can be applied.

[0191] The liquid supplied to the gap space may have the same or substantially the same composition as the plating solution, or may contain the same type of metal ions as the metal constituting the plating film to be formed. These liquids replenish the substances that decrease as the plating reaction progresses, thereby contributing to the stable continuation of the plating process. Note that "substantially the same" here means that the main components are common and the basic chemical properties are roughly the same, and includes cases where there are slight differences in the content of each component, and cases where only the presence or absence, type, content, etc. of additives are different. [Industrial Applicability]

[0192] The present invention is suitable for use in a technique for forming a coating by plating one main surface of a substrate, and is particularly effective when a large rectangular substrate is to be processed. [Explanation of symbols]

[0193] 1. Plating equipment 2. Conveyor section 4. Plating section 7 Power supply section 41 Plating tank (treatment tank) 40,47 Chuck part (holding part) 61,62 Liquid supply section 400 Chuck mechanism (holding part) 412 Cathode Electrode 413,423 Lifting mechanism 450 Isolation tank 451 Anode Electrode 453 Anode Electrode 611(611a~611i) Piping 612,622 Discharge port 613a~613i Control valve (supply control section) GS Gap Space L, L2 Plating solution (plating solution) S-substrate Sa (of substrate S) top surface (one main surface)

Claims

1. A plating apparatus for plating at least one main surface of a substrate, comprising: A treatment tank for storing a plating solution; a holder that holds the substrate in a horizontal position with the one main surface facing upward in the processing tank; a cathode electrode in contact with a peripheral portion of the one main surface of the substrate held by the holding portion; an anode electrode disposed above the substrate held by the holder, the anode electrode having a lower surface facing the one main surface; a liquid supply section that is provided with a discharge port that opens toward a gap space between the anode electrode and the one main surface, and that supplies liquid from the discharge port toward the plating solution that fills the gap space; A plating apparatus comprising:

2. 2. The plating apparatus according to claim 1, wherein the liquid supply unit has a pipe disposed in the gap space along a lower surface of the anode electrode and through which the liquid is delivered, the discharge port being provided on a lower surface of the pipe.

3. The liquid supply unit includes: A plurality of the pipes each having the discharge port and not connected to each other; a supply control unit that sets the supply amount of the liquid to each of the plurality of pipes individually; The plating apparatus according to claim 2 .

4. 4. The plating apparatus according to claim 3, wherein when a continuous virtual area including all of the outlets provided in one of the pipes is defined as a corresponding area of ​​the pipe in a plan view, the corresponding areas of each of the multiple pipes can be defined so as not to overlap with each other.

5. 2. The plating apparatus according to claim 1, wherein the liquid supply unit is disposed to the side of the gap space outside the substrate in a plan view, and has a nozzle with the discharge port provided on a side facing the gap space for discharging the liquid.

6. The plating apparatus according to claim 5 , wherein a pair of the nozzles are provided with the gap space therebetween.

7. 2. The plating apparatus according to claim 1, wherein an electrolytic diaphragm is provided between the anode electrode and the one main surface, and the gap space is a space sandwiched between the electrolytic diaphragm and the one main surface.

8. The plating apparatus of claim 1 , wherein the liquid has the same or substantially the same composition as the plating solution.

9. 2. The plating apparatus according to claim 1, wherein the liquid contains metal ions of the same kind as the metal constituting the plating film to be formed.

10. A plating method for plating at least one main surface of a substrate, comprising the steps of: holding the substrate by a holder in a horizontal position with the one main surface facing upward in a treatment tank that stores a plating solution; a step of bringing a cathode electrode into contact with a portion of the one main surface of the substrate held by the holding unit, while disposing an anode electrode above the substrate so as to face the one main surface; applying a voltage between the anode electrode and the cathode electrode; Equipped with a discharge port that opens toward a gap space between the anode electrode and the one main surface, and a liquid is supplied toward the plating solution filling the gap space, during at least a portion of a period during which the voltage is applied between the anode electrode and the cathode electrode.

11. The plating method of claim 10 , wherein the liquid has the same or substantially the same composition as the plating solution.

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