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] Technology for forming a thin metal film by plating on the surfaces of various substrates, such as semiconductor substrates, printed wiring boards, and glass substrates, is widely used. For example, Patent Document 1 discloses a dip-type plating apparatus for forming a thin metal film on a semiconductor substrate, in which the plating solution is discharged from piping arranged in a grid pattern within the processing tank, thereby achieving uniformity in the plating solution within the processing tank. This prevents uneven thickness of the plating film caused by uneven plating solution composition. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-026708 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, substrates have become larger, and even large substrates with sides exceeding one meter are being manufactured. For such large substrates, it is difficult to hold and transport the substrates vertically as described in Patent Document 1. Therefore, the substrates must be transported horizontally, with the surface to be plated facing upward, using a conveyor or the like. Furthermore, to prevent uneven film thickness due to biased current density distribution, it is necessary to position the anode electrode so that it faces the entire upper surface of the substrate.

[0005] In this configuration, the composition of the plating solution gradually changes in the gap between the substrate and the anode as the plating reaction progresses, which impairs the uniformity of the plating film. In particular, in the center of the substrate, where a fresh supply of plating solution from an external source is not possible, problems such as insufficient film thickness and non-uniform film quality arise. However, no technology has been proposed to address these problems.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a plating apparatus and a plating method that can obtain a plating film with uniform thickness and quality, even when performing plating processing by placing a large substrate and a corresponding anode electrode opposite each other. [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, comprising: a treatment tank for storing a plating solution; a holder for holding the substrate in a horizontal position within the treatment tank with the one main surface facing upward; a cathode electrode in contact with a peripheral edge portion of the one main surface of the substrate held in the holder; an anode electrode disposed above the substrate held in the holder with its underside facing the one main surface; and a liquid supply unit having 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. Here, in one example, the liquid supply unit has a plurality of pipes through which the liquid is transported but which are not connected to each other, and a supply control unit that individually sets the amount of liquid supplied to the plurality of pipes, and the plurality of pipes are each arranged along the underside of the anode electrode in the gap space, and include a pipe arranged along the center of the underside of the anode electrode and a pipe arranged to surround it, and the discharge outlet is provided on the underside of each of the plurality of pipes. In another example, the liquid supply section has a plurality of nozzles arranged on both sides of the gap space, outside the substrate in a plan view, and on the sides of the gap space, and each of the nozzles has an outlet on the side facing the gap space to eject the liquid.

[0008] Another aspect of the present invention is 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; bringing a cathode electrode into contact with a portion of the one main surface of the substrate held by the holder, while placing 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. Here, in one example, a plurality of pipes are provided along the underside of the anode electrode in a gap space sandwiched between the anode electrode and the one main surface, the plurality of pipes including a pipe arranged along the central portion of the underside of the anode electrode and a pipe arranged so as to surround the central portion, and an outlet is provided on the underside of each of the plurality of pipes. During at least a part of the period during which the voltage is applied between the anode electrode and the cathode electrode, Each of the piping A liquid is supplied from a discharge port toward the plating solution filling the gap space. Furthermore, the supply amounts of the liquid to the plurality of pipes are individually set. do. In another example, a plurality of nozzles are provided on both sides of a gap space sandwiched between the anode electrode and the one main surface and outside the substrate in a plan view, and each of the nozzles has an outlet on the side facing the gap space to eject the liquid, and supplies liquid from the outlet of each of the pipes toward the plating solution filling the gap space during at least a portion of the period during which the voltage is applied between the anode electrode and the cathode electrode.

[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. This liquid has the effect of stirring the plating solution filling the gap space, thereby reducing 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, if 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, "substantially the same" liquid composition 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, or cases where only the presence, type, content, etc. of additives are different.

[0011] Furthermore, if the liquid contains metal ions of the same type as the metal that constitutes 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. [Effects of the Invention]

[0012] As described above, according to the present invention, by supplying the liquid toward the gap between the anode electrode and the substrate, non-uniformity in the plating solution filling the gap is eliminated, and therefore, even when a plating process is performed by placing a large substrate and a corresponding anode electrode facing each other, a plating film with uniform thickness and quality can be obtained. [Brief explanation 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; [Figure 2] FIG. 2 is a diagram showing a schematic configuration of a plating processing section. [Figure 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. [Figure 5] FIG. 2 is a diagram schematically illustrating the configuration of a main part of an anode electrode unit. [Figure 6] FIG. 2 is a diagram schematically illustrating a state in which an isolation tank is immersed in a plating tank. [Figure 7] FIG. 10 is an external perspective view showing a support mechanism for a separator in the anode electrode unit. [Figure 8] FIG. 2 is a diagram schematically illustrating the supply and discharge of plating solution to and from an isolation tank. [Figure 9] 1A to 1C are diagrams schematically showing two modes 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] 10A and 10B are diagrams schematically illustrating the effect of liquid supply. [Figure 13] FIG. 10 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 schematically illustrating the operation of each unit. [Figure 17] FIG. 10 is a diagram showing a modified example of the anode electrode. DETAILED DESCRIPTION OF THE INVENTION

[0014] Specific aspects of the plating apparatus according to the present invention will be described below by showing specific embodiments.

[0015] FIG. 1 is a diagram showing the schematic configuration of one embodiment of a plating apparatus according to the present invention. This plating apparatus 1 is an apparatus that forms a metal (e.g., gold) coating 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 boards, 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, with the horizontal direction and perpendicular to the plane of the drawing in FIG. 1 being the X direction, and the horizontal direction perpendicular to this and parallel to the plane of the drawing in FIG. 1 being the Y direction. The vertical direction is also defined as the Z direction. In each diagram, dotted arrows indicate the movement direction of each component.

[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. Note that in FIG. 1 and the following figures, the illustration of some components may be omitted as appropriate to avoid cluttering the drawings. Specifically, components that contribute relatively little to the establishment of the invention, such as a holding mechanism for holding components, a cover for covering the components, and a mechanism for attaching them to the housing 10, and whose structure is considered to be capable of applying appropriate publicly known technology and therefore does not require any special explanation, may be omitted from the illustration.

[0017] FIG. 1 is a front view of a plating apparatus 1. The plating apparatus 1 is provided with a transport unit 2 that transports a substrate S along the Y direction. The transport unit 2 includes multiple transport rollers 21 arranged along the Y direction. The transport rollers 21 are each supported by a support mechanism (not shown) so that they can rotate freely around the X direction as their axial direction. By rotating the transport rollers 21 using a drive mechanism (not shown), the transport unit 2 transports the substrate S in a horizontal position in the Y direction. The rectangular substrate S is transported with one of its four peripheral sides at the front. Hereinafter, the transport path of the substrate S will be represented by the symbol P, and the transport direction will be 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 the necessary processing in each of the above processing sections while being transported in the Y direction by the transport section 2.

[0019] The loading section 3 receives and temporarily holds unprocessed substrates S transported from outside, and supplies the substrates S to the plating section 4 at the required timing. The plating section 4 is the processing main body that performs the plating method according to the present invention, and performs plating by immersing the substrates 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 rinsing liquid in an internal space large enough to accommodate the substrate S. An opening is provided on the Y-direction side surface of the rinsing tank 51 at a portion overlapping with the transport path P, and shutters 51a and 51b are provided to the opening in a manner that allows them to be opened and closed.

[0021] The tray 52 is disposed below the rinse tank 51 and receives the rinse liquid spilled from the rinse tank 51. The rinse liquid supply / discharge unit 59 supplies the rinse liquid to the rinse tank 51 and discharges the rinse liquid from the rinse tank 51 as needed. The rinse processing unit 5 performs a rinse process on the substrates S immersed in the plating solution in the plating processing unit 4. Water, for example, is used as the rinse liquid. The unloading unit 6 temporarily stores the substrates S after the rinse process until they are 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 predetermined processes. The hardware configuration of the control unit 9 can be, for example, 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 control commands from the control unit 9.

[0023] The plating processing unit 4 includes a plating tank 41, vats 42 and 44, a chuck unit 40, a moving mechanism 43, an anode electrode unit 45, a cleaning mechanism 48, and a plating solution supply / discharge unit 49. The plating tank 41 is capable of storing plating solution in an internal space large enough to accommodate a substrate S. The vat 42 is disposed below the plating tank 41 to receive spilled plating solution. The chuck unit 40 is disposed above the plating tank 41 to hold the substrate S to be plated. The vat 44 is disposed adjacent to the vat 42 on the (-Y) side below the plating tank 41. The cleaning mechanism 48 cleans the chuck unit 40 with an appropriate cleaning solution (e.g., water). For this purpose, the cleaning mechanism 48 includes a cleaning nozzle 481 ( FIG. 2 ) disposed within the vat 44 and a cleaning solution supply / discharge unit 482 that supplies cleaning solution to the cleaning nozzle 481. The plating solution supply / discharge unit 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 the 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. To avoid cluttering the figures, 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 that overlap with transport path P, and openable / closable shutters 41a and 41b are provided at the openings, respectively. When shutters 41a and 41b are in the open state, substrates 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 substrates S to be carried into plating tank 41 and processed substrates S to be carried out of plating tank 41.

[0026] On the other hand, in the closed state, the opening on the side of plating tank 41 is closed. At this time, transport path P for substrate S is blocked, but plating solution can be stored inside plating tank 41 to a height exceeding the height of the opening. After substrate S is accommodated in plating tank 41 with shutter 41a on the (-Y) side open, shutter 41a is closed and the internal space of plating tank 41 is filled with plating solution L, whereby substrate S is immersed in plating solution L and plated. Thereafter, when the plating solution is discharged and shutter 41b on the (+Y) side is opened, the liquid level of plating solution L drops below the bottom edge of the opening, and the plated substrate S is transported to rinse unit 5. 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 the rotation shaft 22 of the transport roller 21. The rotary motor 23 rotates in response to a control command from the control unit 9, causing the transport roller 21 to rotate, 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] 3(a), two sets of chuck units 40 are arranged corresponding to both ends in the X direction of the substrate S accommodated in the plating tank 41. In FIGS. 1 and 2, only one set on the (+X) side is shown. The two sets of chuck units 40 are arranged symmetrically with respect to the YZ plane, but have the same basic structure. That is, each chuck unit 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 movement mechanism 43 attached to the upper frame 11, one of the frame members constituting the housing 10. More specifically, the movement mechanism 43 includes a guide rail 431 fixed to the upper frame 11 above the plating processing unit 4 and extending in the Y direction, a slider 432 engaged with the guide rail 431, and a drive source (not shown) that moves the slider 432 in the Y direction along the guide rail 431. These components can be configured using an appropriate linear motion mechanism, such as a linear motor, a linear motion guide mechanism, a chain drive mechanism, or a belt drive mechanism. For example, a single-axis robot with such a drive mechanism already integrated can be suitably used.

[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 movement 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 these 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 orientation of the substrate S in the plating tank 41, and also brings a built-in cathode electrode into electrical contact with one main surface of the substrate S. A DC voltage is then applied between the anode electrode and cathode electrode (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 top 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 is gripped at both ends in the X direction by a plurality of chuck mechanisms 400 provided along the Y direction, i.e., the transport direction Dt of the substrate S. By gripping the substrate S, the chuck mechanisms 400 not only contribute to stably maintaining the orientation of the substrate S, but also apply a uniform potential over a wide area by bringing the cathode electrode 412 extending in the Y direction into contact 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 a 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 grips a substrate S. Note that, when explaining the structure and operation of the chuck mechanism 400 below, the chuck mechanism 400 that holds the (-X) side end of the substrate S will be mainly used as an example. However, by considering the same structure inverted around the Z axis, it is possible to understand the structure and operation of a chuck mechanism that holds the (+X) side end of the substrate S. Also, to improve visibility in the drawing, some of the components of the chuck mechanism 400 are omitted from 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, thin, flat plate-like member extending with the Y direction as its longitudinal direction, and grip the substrate S by having the lower surface 411b of the upper chuck 411 abut against the (-X) side end of the upper surface Sa of the substrate S and the upper surface 421a of the lower chuck 421 abut against the (-X) side end of the lower surface Sb of the substrate S. In practice, a cathode electrode 412 is attached to the lower 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. 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 sealing member 415 elastically deforms to airtightly surround the cathode electrode 412. Therefore, even when the substrate S is immersed in the plating solution, the cathode electrode 412 is kept dry without coming into contact with the plating solution. This makes it possible to prevent corrosion of the cathode electrode 412 or the formation of a film 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 defining the position of the substrate S in the height direction (Z direction). The lower chuck 421 also functions 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 that the cathode electrode 412 and the substrate upper surface Sa are in reliable electrical contact.

[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 an elevating mechanism 414 so as to be movable up and down. The upper chuck 411 is fixed to the shaft member 413 using, for example, a screw, and is detachable (i.e., replaceable). The elevating mechanism 414 has an appropriate direct-acting mechanism such as a solenoid, a linear motor, or a ball screw mechanism, and raises and lowers the shaft member 413. This raises and lowers the upper chuck 411 attached to the lower end of the shaft member 413. Here, a unit integrally configured including the upper chuck 411, the shaft member 413, the elevating mechanism 414, etc. is referred to as the "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 an elevating mechanism 424 so as to be able to move up and down freely. The lower chuck 421 is firmly connected to the shaft member 423 using, for example, a screw, and is therefore detachable. The elevating mechanism 424 has an appropriate direct-acting mechanism, for example, a solenoid, a linear motor, or a ball screw mechanism, and raises and lowers the shaft member 423. This causes the lower chuck 421 attached to the lower end of the shaft member 423 to rise and lower. Here, a unit integrally configured including the lower chuck 421, the shaft member 423, the elevating 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 advancing and retreating mechanism 402. Specifically, a support member 403 to which the lower chuck unit 420 is attached is connected to a movable part of the advancing and retreating mechanism 402, which moves in the X direction. The advancing and retreating 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 / lowering mechanism 424, and can move forward and backward in the X direction by the advancing / retreating mechanism 402 moving the lifting / lowering mechanism 424.

[0043] When the lower chuck 421 is advanced to the farthest (+X) side within its movable range, the (+X) side tip of the lower chuck 421 is positioned on the (+X) side of the edge surface of the substrate S, as shown by the solid line in Fig. 4(b), and the upper surface 421a of the lower chuck 421 can support the lower surface Sb of the substrate S. On the other hand, when the lower chuck 421 is retreated to the farthest (-X) side within its movable range, as shown by the dotted line in Fig. 4(b), the (+X) side tip of the lower chuck 421 is retreated to the (-X) side of the edge surface of the substrate S. This prevents the lower chuck 421 from coming into contact with the substrate S when it is raised or lowered.

[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 height of the substrate S supported by the transport rollers 21. Therefore, the substrate S is held in a horizontal position with its upper surface flat in the plating tank 41. 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 FIGS. 1 and 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 housed in a box-shaped isolation tank 450 that is open at the top.

[0046] 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), the anode electrode 451 is made up of nine electrode plates 451a to 451i arranged in a 3 x 3 matrix. The lower surfaces of the electrode plates 451a to 451i that face the substrate S are in the same horizontal plane.

[0047] Anode electrode 451 is electrically connected to power supply unit 7 and receives a supply of electrical energy. More specifically, power supply unit 7 has multiple output units 71a-71i that can set output currents independently of one another, and the multiple electrode plates are electrically connected to the multiple output units one-to-one, with output unit 71a connected to electrode plate 451a and output unit 71b connected to electrode plate 451b. Each of 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 for the output current.

[0048] The output current of each of the output units 71a to 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 about the current value to be output by each of the output units 71a to 71i. Each of the output units 71a to 71i outputs a current having a predetermined current value based on the information stored in the setting storage unit 72. The current value of each of the output units 71a to 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 user input.

[0049] The isolation tank 450 includes a frame 452 that laterally surrounds the anode electrode 451, and an electrolytic diaphragm 453 that closes the lower part of the frame 452 and forms the bottom of the isolation tank 450. The frame 452 is roughly rectangular in plan view, is perforated in the vertical direction, and is made of a material that is corrosion-resistant to the plating solution L, such as a resin material. The electrolytic diaphragm 453 is formed in the shape of a flat plate or sheet 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, thereby forming a rectangular box-shaped isolation tank 450 that is open at the top. The anode electrode 451 is housed in the internal space 454 of this isolation tank 450, as indicated by the dashed-dotted arrow. To enable this, the frame 452 that constitutes the isolation tank 450 has a rectangular shape in plan view, with its inner wall being slightly larger than the outer size of the anode electrode 451. Furthermore, in consideration of the convenience of replacing the electrode material as it wears out, 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 containing the anode electrode 451 is immersed in the plating solution L stored in the plating tank 41.

[0052] FIG. 6 is a schematic diagram illustrating a state in which an isolation tank is immersed in a plating tank. As shown in FIG. 6(a), the isolation tank 450 is positioned so that at least the lower surface of the electrolytic diaphragm 453 forming the bottom portion thereof is in contact with the plating solution L stored in the plating tank 41. A 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 vary as the treatment progresses. Alternatively, the second plating solution L2 may be substantially the same as the first plating solution, for example, in terms of the type of main component, but may differ in concentration, or in at least one of the presence, type, or content of an additive. Depending on the purpose, a liquid with a different composition from 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 solution L (+L2) and the electrolytic diaphragm 453 interposed between them.

[0054] A predetermined gap G1 greater than zero is provided between the lower surface of the anode electrode 451 and the upper surface of the electrolytic diaphragm 453. A predetermined gap G2 greater than zero is also 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 by the following formula: 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 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, nonuniformity in the current density distribution on the upper surface of the substrate S affects the quality of the plating film. In other words, to obtain a film with uniform composition and thickness, it is desirable to achieve a uniform current density distribution across the surface of the substrate S. However, maintaining a uniform current density is not easy due to the fact that the substrate S is made of insulating glass, its rectangular outer shape, and electrical contact with the cathode electrode 412 is limited to the periphery of the substrate S. In electrolytic plating techniques such as this embodiment, in which an anode electrode faces one main surface of the substrate and a cathode electrode contacts the periphery of the substrate, current concentration is likely to occur at the periphery of the substrate. As a result, the film thickness at the periphery tends to be larger than that at the center. In particular, to shorten the takt time of the plating process, it is necessary to increase the amount of current supplied from the power supply 7, but this also increases current imbalance.

[0058] One approach to this problem is to cover the periphery of the substrate with a shield plate to reduce current concentration. However, for large substrates, such as glass substrates for display devices, 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 yet sufficient knowledge about the size and shape of the shield plate that is effective for rectangular substrates.

[0059] In this embodiment, the anode electrode 451 is divided into multiple electrode plates 451a-451i. Output units 71a-71i, which can set 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 correct the current imbalance and make the current density closer to a uniform distribution, thereby improving the uniformity of the plating film.

[0060] As mentioned above, current concentration is likely to occur at the periphery of a rectangular substrate. In light 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, by setting the amount of current to the centrally arranged electrode plate 451e to be larger than that of the other electrode plates, it is expected that the current distribution can be made more uniform.

[0061] Furthermore, 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 to 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, it is sufficient to measure the current distribution through a preliminary experiment and determine a set value of the current to be supplied to each of the electrode plates 451a to 451i for each of the output units 71a to 71i based on the results so as to correct any bias in the current distribution.

[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 "electrode current density" is defined as the current value applied to each electrode plate divided by the area of ​​the lower surface (surface facing the substrate S) of that electrode plate (hereinafter referred to as the "electrode area"). If this electrode current density is considered to represent the current density in the portion of the substrate upper surface Sa facing that electrode plate, then the output current value to each of the electrode plates 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 of the electrode plates 451a-451i whether the electrode areas of the electrode plates 451a-451i are the same or different.

[0064] For example, in the case described above where the current density tends to be high at the periphery of the substrate S and low at the center, the electrode current density can be set to be high at the electrode plate 451e located in the center and low at the other electrode plates located around it, thereby achieving a uniform current density distribution overall. Note that for electrode plates with a portion of their undersides located outside the substrate S in a plan view and not facing the substrate S, the area of ​​the portion facing the substrate S may be considered the effective electrode area. Furthermore, unless the periphery of the electrode plate protrudes significantly farther outward than the substrate S, the current output from the portion outside the substrate S may also reach the substrate S and contribute to the plating reaction. In this case, the entire electrode plate may be considered 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 can be read out to operate the output units 71a to 71i. The user and the control unit 9 can change these settings as needed. This makes it possible to deal with cases where the current distribution needs to be changed, for example, when changing the size of the substrate S.

[0066] It is also possible to construct the isolation tank 450 using an ion-permeable material not only on the bottom surface but also on the sidewall surface. However, ion migration via the sidewall surface can cause current concentration at the periphery of the substrate, impairing the uniformity of the plating film. By allowing ions to migrate only via the bottom surface of the isolation tank opposite the top surface of the substrate S, such current concentration can be prevented.

[0067] For the same reason, if the cathode electrode 412 is placed directly below the electrolytic diaphragm 453 that forms the bottom of the isolation tank 450, a shorter current path is formed in that portion, causing current concentration. To avoid this, it is preferable that the cathode electrode 412 be in contact with 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 effective to construct the frame 452 from a material that is not permeable to ions, or to make the outer size of the isolation tank 450 in plan view (more precisely, the outer size of the electrolytic diaphragm 453 that forms 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), this embodiment meets these requirements.

[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 example, to form a copper plating film on the substrate S, which is a glass substrate, a copper sulfate aqueous solution can be suitably used as the plating solution L (L2), and a copper plate can be suitably used 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] During this process, the anode electrode 451 gradually dissolves into the plating solution L (L2), and insoluble impurities contained in the electrode material are liberated into the solution from the anode electrode 451. The insoluble residue thus produced 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 placed above it. As a result, anode slime consisting of impurities liberated from the anode electrode 451 settles in the plating solution toward the substrate S placed 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 separated 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 its 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 ensured, 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 insoluble components is blocked by the electrolytic diaphragm 453 and does not adhere to the substrate S.

[0075] Furthermore, since the box-shaped isolation tank 450 has an open top, the anode electrode 451 housed in the isolation tank 450 is open above. This allows the anode electrode 451 to be easily attached to and detached from the isolation tank 450. As the reaction progresses, the anode electrode 451 wears out and must be replaced periodically. The above structure also contributes to increasing the convenience of such replacement work.

[0076] Anode electrode 451 is divided into multiple electrode plates 451a to 451i. Therefore, replacement can be performed for each electrode plate. This not only improves the workability of replacement, but also leads to effective use of resources, since only the electrode plates of anode electrode 451 that need replacing can be replaced.

[0077] The horizontal spacing between the electrode plates 451a-451i can be, for example, smaller than the distance between the bottom surface of each electrode plate 451a-451i and the substrate S, and more preferably, less than half that distance. If the spacing between the electrode plates is too large, sufficient current may not be supplied to areas of the substrate top surface Sa that do not face any of the electrode plates, resulting in uneven current density. It is known that the current flowing from an electrode plate spreads to a certain extent from the outer edge of the electrode plate in the liquid. According to the inventor's knowledge regarding this, setting the spacing as described above makes it possible to suppress such current unevenness.

[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. Furthermore, in order to refresh the plating solution L2 and prevent 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 satisfies these 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, the anode electrode 451 housed in the internal space 454 of the isolation tank 450 is not shown in order to clearly show the structure of the support mechanism. 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 move 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 the following way: the first support frame 461, which is arranged at the bottom, supports the isolation tank 450; the second support frame 462 arranged above it supports the first support frame 461; the third support frame 463 arranged further above it supports the second support frame 462; and the third support frame 463 is fixed to the upper frame 11 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 that is vertically penetrated. Four sets of lift guide mechanisms 466, which operate in the vertical direction, are attached to the third support frame 463, which is the uppermost of these. Specifically, linear bushings 466a of the lift guide mechanisms 466 are provided at the four corners of the support frame 463. The linear bushings 466a are hollow cylindrical members that are vertically penetrated, and a movable rod 466b is inserted into the hollow portion. The movable rod 466b extends downward from the linear bushings 466a, and its lower end is connected to the second support frame 462 located below.

[0082] When the lifting mechanism 47 (described later) operates in response to a control command from the control unit 9, the movable rod 466b moves up and down within a predetermined movable range, thereby lifting and lowering the second support frame 462 connected to the lower end of the movable rod 466b. 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 operating in the up-and-down direction, are attached to the second support frame 462. Specifically, bushings 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 bushings 465a. The movable rods 465b extend downward from the linear bushings 465a, and their lower ends are connected to the first support frame 461 located 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, thereby lifting and lowering the first support frame 461 connected to the lower end of the movable rod 465b. 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 lifting guide mechanisms 465, 466 can move the isolation tank 450 in the vertical direction in cooperation with the lifting mechanism 47. Various mechanisms other than the combination of a cylindrical linear bush and a movable rod described above can be applied to the lifting guide mechanisms 465, 466. For example, various mechanisms that can restrict the movement of an object in one direction can be used, such as a linear guide mechanism that combines a guide rail and a slider. The lifting guide mechanisms 465, 466 may also be provided with a damper function, similar to the lifting guide mechanism 464 described below.

[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 bushings 464a of the lifting guide mechanisms 464. As will be described later, the lifting guide mechanisms 464 have a damper mechanism that reduces the impact transmitted to the isolation tank 450 when the isolation tank 450 is raised or lowered.

[0087] Furthermore, a frame 455 made up of a combination of plate members 455a extending in the X direction and plate members 455b extending in the Y direction is attached to the upper part of a frame 452 constituting the isolation tank 450, and hinge members 455c are attached to four locations on the upper part of the frame 455. The lower ends of 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 axes parallel to the X axis. In this way, the isolation tank 450 is supported by the support frame 461 via the support mechanism 460.

[0088] Furthermore, between the two hinge members 455c, 455c, located on the (-Y) side, of 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 is capable of free rotation. The function of the roller member 455f will be described later.

[0089] Additionally, equipment for supplying and discharging plating solution L2 to and from isolation tank 450 is disposed around isolation tank 450. That is, above isolation tank 450, a nozzle 491 is provided for discharging the plating solution delivered from plating solution supply / discharge unit 49 toward internal space 454 of isolation tank 450. Nozzle 491 is attached to 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 on 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 that is primarily made of non-flexible tubing, thereby allowing the piping to bend at the insertion point. Flexible joints are widely used, for example, to absorb misalignment and vibrations at the connection points between pipes.

[0091] As will be described later, in order to efficiently discharge the plating solution, the isolation tank 450 is provided so as to be rotatable about the X-axis. By inserting a flexible joint 493 into the piping 492, it is possible to form a supply path for the plating solution between the plating solution supply / discharge unit 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 that constitutes the isolation tank 450, and a discharge pipe 494 is connected to this through-hole 452a. Similar to 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, an elevating mechanism 47 fixed to the frame 11 of the housing 10 is provided. For the sake of explaining the principle, the elevating mechanism 47 is assumed to be a winch mechanism that raises and lowers an object by winding up a wire. That is, a wire 471 hangs downward from the elevating mechanism 47, and the wire 471 passes through openings in the centers of the support frames 461 to 463 and reaches a position directly above the isolation tank 450. 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 midpoint between the two hinge members 455c, 455c aligned 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 direct-acting 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 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 bushing (also referred to as a direct acting bearing or linear bearing) 464a through which a movable rod 464b extending in the vertical direction (Z direction) is inserted, a base member 464c to which the linear bushing 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. A known shock absorber, for example, can be used as the damper mechanism 464e.

[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 the function of allowing the movable rod 464b to move up and down while regulating its range of movement and also cushioning 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 the 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 outline 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, the 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, it is not possible to provide a discharge path below the isolation tank 450 because the substrate S is placed directly below the isolation tank 450.

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

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

[0102] To satisfy these requirements while draining the plating solution, an outlet is provided on the sidewall of the isolation tank 450 to drain the plating solution to the side. However, this inevitably impairs the smoothness of drainage compared to when an outlet is provided on the bottom surface. Therefore, in this embodiment, a through-hole 452a serving as an outlet is provided on the (+Y) side surface of the isolation tank 450, and a drain pipe 494 is connected to the through-hole 452a. When draining the plating solution L2, the isolation tank 450 is lifted on the side opposite the outlet, i.e., the (-Y) side, to tilt the bottom surface. This arrangement facilitates the drainage of the plating solution L2 from the internal space 454.

[0103] Specifically, the lifting mechanism 47 winds up the wire 471, thereby pulling up the frame 455 and lifting the (-Y) side end of the isolation tank 450, as shown by the dashed arrow in FIG. 8(b). The isolation tank 450 is thus tilted with its bottom surface tilted relative to the horizontal plane, causing the plating solution L2 stored in the internal space 454 to flow toward the through-hole 452a, which serves as a discharge port, as shown by the hollow arrow in FIG. 8(b). This promotes discharge of the plating solution L2. The waste liquid that flows into the piping 494 is collected by the plating solution supply / 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 for such tilting of the isolation tank 450. That is, in each of a pair of lift guide mechanisms 464, 464 arranged 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] Furthermore, flexible joints 493, 495 are inserted into 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 explanation up to this point has omitted details in order to explain the overall configuration and basic operation of the apparatus, the plating apparatus 1 is provided with a mechanism for supplying a 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 this configuration, plating solution L tends to accumulate in the gap space, which can cause changes in composition as the plating reaction progresses. This is because substances consumed in the plating reaction are not replenished and 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 as needed during the current-carrying period. The liquid supply mechanism provided in this embodiment to enable this is described below.

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

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

[0110] 9(b), liquid supply mechanisms 62 are 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 the 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, the liquid is discharged laterally from the side of the gap space GS, as indicated 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, thereby eliminating stagnation of the plating solution L in the gap space GS. In particular, a more active effect can be expected when the liquid contains a substance that contributes to the plating reaction. 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 will always be 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 is different, or at least one of the presence, type, or content of additives is partially different.

[0113] Furthermore, for example, by using a liquid containing a component whose content in the liquid changes as the plating reaction progresses, it becomes possible to replenish the component that is reduced 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 becomes possible to suppress the reduction of the component and to 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, plating solution L also meets this requirement. In the following, a liquid having the same composition as plating solution L will be used.

[0114] The structure of each embodiment will be described in detail below, but either 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 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, the 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 on / off control of the supply of liquid to each of the pipes 611a to 611j and adjustment of the supply amount.

[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 schematically illustrating 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 indicated by the arrows. This prevents plating liquid from stagnating 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 lost in the plating reaction.

[0120] Because the pipes 611 (611a to 611j) are disposed between the anode electrode 451 and the substrate S, there is a concern that they may block the path of 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), current flowing from a certain point on the anode electrode 451 spreads and diffuses to a certain extent as it proceeds toward the substrate S. The width of the pipes 611 and their horizontal and vertical arrangements can 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 within the predetermined spread angle range when viewed from at least one position, preferably multiple positions, of the anode electrode 451. In this way, the effect of shielding by the pipes can be avoided.

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

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

[0123] 10(b), consider an area that, in plan view, continuously covers all of the discharge ports 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 defining "corresponding areas" in this way, it is possible to define one corresponding area without intersecting with any other corresponding areas or being divided by other areas. 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 configuration in which multiple discharge ports 612 are provided in one pipe 611 as described above, the discharge rate from each discharge port 612 cannot be adjusted individually, and adjustment of the discharge rate is performed for each pipe. For this reason, if the liquid supply from the pipe to be controlled interferes with the liquid supply from another adjacent pipe, the liquid supply rate at each position in the gap space GS may not follow the desired pattern.

[0126] In the piping pattern described above, the region (corresponding region Ri) to which liquid is supplied from one pipe, for example, the outlet 612 connected to pipe 612i, and the region (corresponding region Re) to which liquid is supplied from another pipe, for example, the outlet 612 connected to pipe 612e, can be separated, thereby preventing interference between them. 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 needed. For example, since plating liquid tends to stagnate most significantly in the center of the substrate S, supplying more liquid to the center than to other portions can effectively eliminate stagnation.

[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. This makes it easy for current to concentrate near the cathode electrode 412, which can 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, a similar 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] 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 of 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 cause an obstacle when the substrate S is put in or taken out of the plating tank 41.

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

[0131] 13(a), the six liquid discharge nozzles 621 are each assigned the reference numerals 621a to 621f to distinguish them from one another. 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 in 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 amount of liquid supplied 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 toward its interior, and in particular to have the liquid reach the center, the liquid needs to be ejected at a relatively high speed and with a large flow rate. To make this possible, the liquid ejection nozzle 621 has the following structure. That is, as shown in Figure 13(b), the liquid ejection nozzle 621 has a manifold space 624 inside, and multiple ejection ports 622 provided on the side of the liquid ejection nozzle 621 each communicate with this manifold space 624.

[0133] A liquid supply port 625 communicating with the 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. A plurality of liquid supply ports 625 may be provided as necessary. A liquid, specifically a plating solution, is supplied to this liquid supply port 625 from the plating solution supply / discharge unit 49.

[0134] The liquid supplied to the manifold space 624 through the liquid supply port 625, which has a relatively large opening, is then discharged horizontally at high speed from the smaller 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] When liquid is pumped into the gap space GS from both sides of the gap space GS in the X direction, it is thought 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 discharge from each of the liquid discharge nozzles 621a to 621f, it is possible to generate a complex flow of plating liquid within the gap space GS. In particular, by varying 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 described above, the control unit 9 controls each unit of the apparatus and causes the plating apparatus 1 to perform predetermined processing. The hardware configuration of the control unit 9 can be, for example, the same as that of a general computer device. 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 processing. The storage 93 stores various data and a control program 931 on a long-term basis. The input unit 94 and display unit 95 perform user interface functions. The interface unit 96 handles communication with external devices, etc.

[0139] The CPU 91 reads and executes a control program 931 stored in advance in the storage 93, and controls each unit of the apparatus based on the program to perform predetermined operations, thereby realizing 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 / 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 fluids, and a power supply control unit 915 that controls the power supply to the electrodes from the power supply unit 7. At least some of these functional blocks may be configured as, for example, dedicated hardware.

[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 similar basic configuration to the plating apparatus 1 of this embodiment, and also provide 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 outlined as follows. An unprocessed substrate S is loaded into the loading section 3. The substrate S is transported from the loading 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 then rinsed in the rinsing section 5 and is finally unloaded to the unloading section 6.

[0142] FIG. 15 is a flowchart 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 over time T, with the time axis running 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 diagram, 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. However, the upper chuck 411 and the lower chuck 421 may be positioned lower as long as they do not interfere with 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, 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 solution supplied from the plating solution supply / discharge section 49 is stored in the plating tank 41 to a height that prevents it from overflowing from the opening. In the anode electrode unit 45, the isolation tank 450 is retracted upward, and no plating solution is stored in its internal space 454. In the rinsing processing section 5, 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 point, there is no substrate S 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 Figure 15, the dashed arrows indicate 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 positioned opposite 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, plating solution L is supplied from plating solution supply / discharge unit 49 to plating tank 41 (step S103). In parallel with this, plating solution L2 is supplied from plating solution supply / discharge unit 49 to isolation tank 450. As a result, a state is achieved in which substrate S is immersed in plating solution L in plating tank 41, anode electrode 451 is immersed in plating solution L2 in isolation tank 450, and the lower surface of electrolytic diaphragm 453 on the bottom surface of isolation tank 450 is in contact with plating solution L in 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), thereby plating the substrate S. By bringing the cathode electrodes extending in the Y direction into contact with both ends of the upper surface Sa of the substrate S in the X direction, 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 operated 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 within the plating solution L.

[0150] At this time, the transport rollers 21 move 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 forward, that is, in a direction to transport 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 reversely, that is, to transport the substrate S in the direction (-Dt) opposite to the transport direction Dt.

[0151] By oscillating the substrate S in the plating solution L in this manner, the plating solution L is agitated, reducing unevenness in the ion concentration in the solution and improving the uniformity of the plating film. The oscillation 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 prevents localized stress from being applied to the substrate S and makes it possible to oscillate the substrate S while maintaining a horizontal position.

[0152] Furthermore, during at least a part of the energizing period, and preferably the entire period, liquid is supplied from the liquid supply units 61, 62. This further promotes the flow of 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 of oscillating the substrate S while supplying a current 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 the plating solution from the isolation tank 450, the isolation tank 450 is retracted upward by the support mechanism 460, and the lifting mechanism 47 is operated to lift the (-Y) side end of the isolation tank 450.

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

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

[0156] It should be noted that 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, there is no problem with some liquid remaining in the tank as long as the liquid is drained to the extent that the substrate S supported in the tank is exposed from the liquid and can be removed. In fact, leaving some liquid remaining can reduce the amount of liquid required to fill the tank when processing the next substrate S. This reduces the amount of liquid consumed and contributes to reducing the environmental impact.

[0157] Meanwhile, after releasing the grip of the substrate S, the chuck mechanisms 400 undergo 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 mechanisms 400, more specifically, the upper chuck 411 and the lower chuck 421, by supplying an appropriate cleaning liquid or spraying 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 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 way, it is possible to prevent any remaining plating solution from adhering to the substrate S when processing the next substrate S. If there are more substrates 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 to be plated, 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 position. The cathode electrode 412 contacts the peripheral edge 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 for the plating film, while isolating the anode electrode 451 from the substrate S for insoluble components and liquid components. This prevents anode slime, which is 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 multiple electrode plates 451a-451i, and each electrode plate is individually connected to an output unit 71a-71i, which is a constant current source of the power supply unit 7. The output current from each output unit 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 achieve a uniform thickness of the plating film.

[0163] Furthermore, with regard to replacement of the plating solution in the isolation tank 450, because 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, an outlet is provided on the side wall surface of the isolation tank 450. Furthermore, 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 the side wall surface on which the 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, plating can be performed with the anode electrode 451 facing the substrate S, while in the inclined position, 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 maintaining the plating solution stored in the internal space 454 in a fresh state.

[0165] In this embodiment, liquid supply mechanisms 61 and 62 are provided above the substrate S to supply liquid to the gap space GS between the substrate S and the anode electrode 451. The supply of liquid from these mechanisms toward the gap space GS promotes the flow of liquid in the gap space GS, eliminating stagnation of the plating solution. If the liquid contains a substance that is reduced by the plating reaction, the plating process can be continued stably while replenishing the 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 multiple 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), large-area electrode plates are placed in the center where a relatively uniform current density can be obtained, while smaller areas are placed 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 depending on the purpose.

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

[0169] As described above, various division patterns of the anode electrode are possible. The division pattern and current distribution to each electrode plate can be determined, for example, by measuring the current density distribution through a preliminary experiment and determining the pattern based on the results. Specifically, in areas of the substrate surface where the current density fluctuations are small, there is little need to finely divide the opposing electrode plate. Conversely, in areas where the current density fluctuations are large, finely dividing the electrode plate can make it easier to adjust the current density distribution. Furthermore, by reducing the current setting value in areas with higher current density, the current density can be made more uniform.

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

[0171] While the division pattern of the anode electrode for adjusting the current density distribution in the gap space GS has been described above, 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 multiple divided pipes 611 in the liquid supply mechanism 61 of this embodiment adjust the ion concentration distribution in the liquid by individually controlling the timing and amount of liquid supply, thereby achieving uniformity in the thickness and quality of the plating film.

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

[0173] <Other> As described above, in the above embodiment, plating apparatus 1 corresponds to the "plating apparatus" of the present invention, and plating tank 41, chuck mechanism 400, cathode electrode 412, and anode electrode 451 function as the "processing tank," "holding unit," "cathode electrode," and "anode electrode" of the present invention, respectively. Furthermore, liquid supply units 61 and 62 both function as the "liquid supply unit" of the present invention.

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

[0175] The present invention is not limited to the above-described embodiment, and various modifications other than those described above are possible without departing from the spirit of the present invention. For example, in the above-described 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] Furthermore, 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] The substrate to be processed does not necessarily have to be a geometric rectangle in the strict sense. For example, even if one of the sides of the substrate has some irregularities, it is sufficient as long as the envelope outline can be regarded as roughly rectangular.

[0178] Furthermore, for example, the power supply unit 7 in the above embodiment includes a constant current output source individually corresponding to each of the electrode plates constituting 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] Furthermore, 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 anode electrode 456 having the division pattern shown in FIG. 16(a), it is possible to realize substantially the same division pattern as the anode electrode 457 shown in FIG. 16(b) by connecting some electrode plates in parallel. Furthermore, 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 using an isolation tank, can also be obtained in a plating apparatus in which the anode electrode is composed of a single electrode plate.

[0181] Furthermore, the problem of plating solution stagnation in the gap space GS can occur regardless of whether the anode electrode is divided or whether it is contained in an isolated tank. 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 is in direct contact with the plating solution in the plating tank.

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

[0183] Furthermore, the anode electrode 451 in the above embodiment is a soluble electrode that contains a metal (e.g., copper) that will be used to form 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 biased current density distribution can occur. For this reason, even in the case of a non-soluble electrode, having a divided structure as described above that allows for individual current adjustment 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 embodiment is effective in eliminating stagnation of plating liquid in the space and achieving uniform film thickness and quality.

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

[0186] In this case, the liquid supply unit may include multiple pipes, each having a discharge port and not connected to one another, and a supply control unit that individually sets the liquid supply amount to each of the pipes. This configuration allows the liquid supply amount to be individually adjusted at each position in the gap space. This makes it possible to achieve an optimal supply mode for achieving uniform plating film thickness and film quality.

[0187] Furthermore, when a continuous virtual area including all of the outlets provided in one pipe is defined as the corresponding area of ​​the pipe in 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 that they do not overlap with each other. With this configuration, it is possible to prevent the liquids supplied from the multiple pipes from interfering with each other and to adjust the flow of the liquid in the gap space with good controllability.

[0188] Furthermore, for example, the liquid supply unit may be configured to be disposed on the side of the gap space outside the substrate in a plan view, and have a nozzle with a discharge port on the side facing the gap space for discharging the liquid. With this configuration, the liquid discharged from the side of the gap space toward the gap space can promote the flow of the plating solution within 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 within the gap space can be effectively promoted by supplying the solution from both sides of the gap space, thereby eliminating stagnation of the plating solution.

[0190] Alternatively, for example, an electrolytic diaphragm may be provided between the anode electrode and one main surface, and in this case, the gap space is the space sandwiched between the electrolytic diaphragm and one main surface. For example, to prevent insoluble impurities generated in the plating solution during the plating reaction from falling 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 main surface of the substrate, can be considered 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 substances that decrease as the plating reaction progresses, thereby contributing to the stable continuation of the plating process. Note that "substantially the same" here refers to having the same main components and generally the same basic chemical properties, and includes cases where there are slight differences in the content of each component, or where only the presence, type, or content of additives is 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 processing large rectangular substrates. [Explanation of symbols]

[0193] 1. Plating equipment 2. Conveyor section 4. Plating department 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 board 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 unit that is provided with a discharge port that opens toward a gap space sandwiched 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; Equipped with the liquid supply unit includes a plurality of pipes through which the liquid is respectively fed but which are not connected to each other, and a supply control unit that individually sets the supply amounts of the liquid to the plurality of pipes; the plurality of pipes are each disposed in the gap space along a lower surface of the anode electrode, and include a pipe disposed along a central portion of the lower surface of the anode electrode and a pipe disposed so as to surround the central portion; The plating apparatus has the discharge port provided on the bottom surface of each of the plurality of pipes.

2. A plating apparatus as described in claim 1, wherein a pipe surrounding the pipe arranged along the central portion and a further pipe surrounding the outside of that are provided.

3. 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 unit that is provided with a discharge port that opens toward a gap space sandwiched 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; Equipped with The liquid supply unit has a plurality of nozzles arranged on both sides of the gap space, outside the substrate in a plan view, and to the side of the gap space, and each of the nozzles has an outlet on the side facing the gap space, and ejects the liquid.

4. 4. 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.

5. 4. The plating apparatus according to claim 1, wherein the liquid has the same or substantially the same composition as the plating solution.

6. 4. 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.

7. A plating method for plating at least one main surface of a substrate, comprising: 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 holder, while placing 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 plurality of pipes are provided along a lower surface of the anode electrode in a gap space sandwiched between the anode electrode and the one main surface, the plurality of pipes including a pipe provided along a central portion of the lower surface of the anode electrode and a pipe provided so as to surround the central portion, and a discharge port is provided on a lower surface of each of the plurality of pipes; a plating method in which, during at least a portion of a period in which the voltage is applied between the anode electrode and the cathode electrode, liquid is supplied from the outlet of each of the pipes toward the plating solution filling the gap space, and the supply amounts of the liquid to the plurality of pipes are individually set.

8. A plating method for plating at least one main surface of a substrate, comprising: 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 holder, while placing 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 plurality of nozzles are provided on both sides of a gap space sandwiched between the anode electrode and the one main surface and outside the substrate in a plan view, each of the nozzles having a discharge port on a side surface facing the gap space, and discharging the liquid; a plating method in which a liquid is supplied from the outlet of each of the pipes toward the plating solution filling the gap space during at least a portion of a period in which the voltage is applied between the anode electrode and the cathode electrode.

9. 9. The plating method according to claim 7, wherein the liquid has the same or substantially the same composition as the plating solution.

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