Substrate holder, plating device, and plating method

Abstract

The present invention relates to a substrate holder, a plating device and a plating method. The substrate holder is used to hold a substrate and bring the substrate into contact with a plating liquid for plating. The substrate holder comprises: a connector for contacting a seed layer formed on the surface of the substrate and supplying power; a protective electrode, which is an insoluble electrode and is biased toward a high potential side relative to the connector; and a holder body having an internal space. When the substrate is held by the substrate holder, the internal space accommodates the outer periphery of the substrate, the connector and the protective electrode in a sealed state from the outside of the substrate holder, and holds liquid covering at least a portion of the protective electrode and the contact portion between the seed layer and the connector.

Description

Technical Field

[0001] The present invention relates to a substrate holder, a plating device and a plating method. Background Art

[0002] During electroplating, if the plating liquid leaks into the substrate holder due to certain undesirable conditions (concavities and convexities on the substrate, deterioration of the seal, etc.), the seed layer may be corroded and / or dissolved by the plating liquid invading the inside of the holder, resulting in poor conductivity and reduced uniformity of the plating.

[0003] In U.S. Patent No. 7,727,366 (Patent Document 1) and U.S. Patent No. 8,168,057 (Patent Document 2), it is described that a fluid is pressurized on one side of a seal of a substrate to prevent the fluid from invading from the opposite side of the seal. In Japanese Patent Publication No. 2020-117763 (Patent Document 3) and Japanese Patent Publication No. 2020-117765 (Patent Document 4), it is described that a liquid is injected into the inner space of the outer periphery of the sealed and housed substrate to prevent the plating solution from invading the inner space, thereby preventing the plating solution from precipitating toward the outer periphery of the substrate and the contact parts.

[0004] Patent Document 1: U.S. Patent No. 7,727,366

[0005] Patent Document 2: U.S. Patent No. 8,168,057

[0006] Patent Document 3: Japanese Patent Application Laid-Open No. 2020-117763

[0007] Patent Document 4: Japanese Patent Application Laid-Open No. 2020-117765

[0008] Even if countermeasures such as those described in the above patent documents are adopted, there is a possibility that the plating liquid will invade the internal space, depending on the unevenness of the substrate and the degree of degradation of the seal. However, the above patent documents do not describe any effective countermeasures for the situation where the plating liquid invades the internal space. In addition, in the wet contact method of plating the substrate by partially covering the joint of the substrate holder and the seed layer of the substrate with a liquid (such as pure water), even if the plating liquid does not invade the internal space, the seed layer may be corroded due to the local battery effect caused by the dissolved oxygen concentration gradient in the liquid. Summary of the Invention

[0009] One of the objects of the present invention is to provide a technology for suppressing degradation of a seed layer of a substrate.

[0010] Another object of the present invention is to suppress a decrease in the uniformity of the plating film thickness even when a plating liquid intrudes into the sealed space of a substrate holder.

[0011] Another object of the present invention is to detect in advance that a plating solution has entered into a sealed space of a substrate holder.

[0012] According to one aspect of the present invention, a substrate holder is provided, which is used to hold a substrate and bring the substrate into contact with a plating liquid for plating, and comprises: a connector for contacting a seed layer formed on the surface of the above-mentioned substrate and supplying power; a protective electrode biased toward a high potential side relative to the above-mentioned connector, or comprising a material having a natural potential lower than that of the above-mentioned seed layer and electrically connected to the above-mentioned seed layer directly or via a conductor; and a holder body having an internal space, which, when the above-mentioned substrate is held by the above-mentioned substrate holder, accommodates the outer periphery of the above-mentioned substrate, the above-mentioned connector and the above-mentioned protective electrode in a state sealed from the outside of the above-mentioned substrate holder, and retains liquid covering at least a portion of the above-mentioned protective electrode and the contact portion where the above-mentioned seed layer contacts the above-mentioned connector. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a perspective view showing the overall structure of a plating apparatus according to one embodiment.

[0014] Figure 2 It is a plan view showing the overall structure of a plating apparatus according to one embodiment.

[0015] Figure 3 It is a schematic diagram for explaining the structure of a plating module of a plating apparatus according to one embodiment.

[0016] Figure 4 This is a cross-sectional view schematically showing an enlarged portion of a substrate holder according to one embodiment.

[0017] Figure 5 It is an explanatory diagram for explaining the flow of a method for controlling a plating apparatus.

[0018] Figure 6 It is an explanatory diagram for explaining the flow of a method for controlling a plating apparatus.

[0019] Figure 7 It is a cross-sectional view schematically showing an enlarged portion of a substrate holder having a protective electrode according to an example.

[0020] Figure 8 FIG. 1 is a plan view of a second holding member of a substrate holder having a protective electrode according to an example.

[0021] Figure 9 This is a cross-sectional view schematically showing an enlarged portion of a substrate holder having a protective electrode according to another example.

[0022] Figure 10 It is a top view of a second holding member of a substrate holder having a protective electrode according to another example.

[0023] Figure 11 This is an explanatory diagram explaining the principle of preventing seed layer corrosion using a guard electrode.

[0024] Figure 12 This is a schematic diagram showing the structure of the power-on test model.

[0025] Figure 13 This is a photograph showing the structure of the power-on test model.

[0026] Figure 14 This is an enlarged photo of a portion of the power-on test model.

[0027] Figure 15 These are photographs showing the results of a current-carrying test in which a guard electrode was provided.

[0028] Figure 16 These are photographs showing the results of a current-carrying test in which no guard electrode is provided.

[0029] Figure 17 It is a schematic diagram for explaining the structure of the plating module of the plating apparatus according to the second embodiment.

[0030] Figure 18 This invention shows a structure in which an insoluble or soluble guard electrode is biased toward a high potential side relative to a joint in the internal space of a substrate holder of a vertical plating module.

[0031] Figure 19 The diagram shows a structure for connecting a soluble guard electrode to a connector in the internal space of a substrate holder of a vertical plating module.

[0032] Figure 20 This is an explanatory diagram for explaining the dissolution of the seed layer due to the dissolved oxygen concentration.

[0033] Figure 21 It is an explanatory diagram for explaining the dissolution of the seed layer caused by the shunt current.

[0034] Figure 22 is an equivalent circuit diagram illustrating the shunt current.

[0035] Description of Reference Numerals

[0036] 10… plating tank; 20… overflow tank; 14… adjustment plate; 15… stirring rod; 16… anode; 17… resistor; 30… substrate holder; 31… first holding member; 32… second holding member; 33… sealed space (inner space); 40… rotating mechanism; 41… rotating shaft; 45… tilting mechanism; 46… lifting mechanism; 47… support shaft; 49… busbar; 50… connector; 55… sealing member; 55A… lip; 60… cleaning liquid (pure water); 90… DC power supply; 215, 225… inner seal; 216… outer seal; 100… loading port; 110… conveying robot; 120 …aligner; 200…prewetting module; 210…front plate; 220…rear plate; 231…inlet passage; 231A…valve; 232…exhaust passage; 232A…valve; 235A, 235B…protective electrodes; 236A…DC power supply; 238A, 238B…protective electrodes; 300…prepreg module; 400…plating module; 500…cleaning module; 600…spin rinse and dry module; 700…conveyor; 800…control module; 801…CPU; 802…storage unit; 1000…plating device; Wf…substrate; Sd…seed layer; Ps…plating solution; Rp…resist. DETAILED DESCRIPTION

[0037] Hereinafter, the plating device 1000 and the plating method according to the embodiment of the present invention will be described with reference to the accompanying drawings. In addition, the accompanying drawings are schematically illustrated to facilitate understanding of the characteristics of the article, and the size ratios of the various components are not limited to the same as the actual ones. In addition, in several drawings, the orthogonal coordinates of XYZ are illustrated for reference. In the orthogonal coordinates, the Z direction corresponds to the top and the -Z direction corresponds to the bottom (the direction in which gravity acts).

[0038] In this specification, "substrate" includes not only semiconductor substrates, glass substrates, liquid crystal substrates, and printed circuit substrates, but also magnetic recording media, magnetic recording sensors, reflectors, optical elements, micromechanical elements, or partially manufactured integrated circuits, and any other processed objects. Substrates include substrates of any shape including polygons and circles. In addition, in this specification, "front surface", "rear surface", "upper surface", "lower surface", "front", "rear", "upper", "lower", "left", "right" and the like are sometimes used for expression, but for ease of explanation, the positions and directions on the paper of the accompanying drawings shown as examples are sometimes different in the actual configuration when the device is used.

[0039] (First embodiment)

[0040] Figure 1 It is a perspective view showing the overall structure of the plating apparatus 1000 according to this embodiment. Figure 21 is a top view showing the overall structure of the plating device 1000 of this embodiment. Figure 1 and Figure 2 As shown, the plating apparatus 1000 includes a loading port 100 , a conveying robot 110 , an aligner 120 , a pre-wetting module 200 , a pre-preg module 300 , a plating module 400 , a cleaning module 500 , a spin-rinse-dry module 600 , a conveying device 700 , and a control module 800 .

[0041] The loading port 100 is a module for carrying a wafer (substrate) housed in a box such as a FOUP (not shown) into the plating device 1000 or for carrying a substrate out of the box from the plating device 1000. In the present embodiment, four loading ports 100 are arranged in a horizontal direction, but the number and configuration of the loading ports 100 are arbitrary. The conveying robot 110 is a robot for conveying substrates, and is configured to transfer substrates between the loading port 100, the aligner 120, and the conveying device 700. The conveying robot 110 and the conveying device 700 can transfer substrates via a temporary placement table (not shown) when transferring substrates between the conveying robot 110 and the conveying device 700.

[0042] The aligner 120 is a module for aligning the position of the orientation plane, notch, etc. of the substrate with a specified direction. In the present embodiment, two aligners 120 are arranged in a horizontal direction, but the number and configuration of the aligners 120 are arbitrary. The pre-wet module 200 replaces the air inside the pattern formed on the substrate surface with the treatment liquid by wetting the plated surface of the substrate with a treatment liquid such as pure water or degassed water before the plating process. The pre-wet module 200 is configured to implement a pre-wet process that easily supplies the plating liquid to the interior of the pattern by replacing the treatment liquid inside the pattern with the plating liquid during plating. In the present embodiment, two pre-wet modules 200 are arranged in a vertical direction, but the number and configuration of the pre-wet modules 200 are arbitrary.

[0043] The prepreg module 300 is, for example, configured to implement a prepreg process in which a treatment solution such as sulfuric acid or hydrochloric acid is used to etch away an oxide film having a large resistance such as a seed layer surface formed on the plated surface of the substrate before the plating process, and the plated substrate surface is cleaned or activated. In the present embodiment, two prepreg modules 300 are arranged in an up-down direction, but the number and configuration of the prepreg modules 300 are arbitrary. The plating module 400 implements a plating process to the substrate. In the present embodiment, the components of 12 plating modules 400, which are arranged in a vertical direction with 3 units and in a horizontal direction with 4 units, are two groups, and a total of 24 plating modules 400 are provided, but the number and configuration of the plating modules 400 are arbitrary.

[0044] The cleaning module 500 is configured to implement cleaning process to the substrate in order to remove the residual plating liquid etc. on the substrate after the plating process. In the present embodiment, two cleaning modules 500 are arranged in the vertical direction, but the number and configuration of the cleaning modules 500 are arbitrary. The spin rinse and dry module 600 is a module for rotating the substrate after the cleaning process at high speed and drying it. In the present embodiment, two spin rinse and dry modules 600 are arranged in the vertical direction, but the number and configuration of the spin rinse and dry modules 600 are arbitrary. The conveyor 700 is a device for conveying substrates between the multiple modules in the plating device 1000. The control module 800 is configured to control the multiple modules of the plating device 1000, and for example, can be composed of a general computer or a special computer having an input and output interface for input and output with an operator.

[0045] An example of a series of plating processes performed by the plating apparatus 1000 will be described. First, a substrate stored in a cassette is loaded into the loading port 100. Next, the transport robot 110 removes the substrate from the cassette in the loading port 100 and transports the substrate to the aligner 120. The aligner 120 aligns the positions of the substrate's orientation flats, notches, and other components with a predetermined orientation. The transport robot 110 delivers the substrate, aligned by the aligner 120, to the transport apparatus 700.

[0046] The conveyor device 700 conveys the substrate received from the conveyor robot 110 to the pre-wetting module 200. The pre-wetting module 200 performs a pre-wetting process on the substrate. The conveyor device 700 conveys the pre-wetting substrate to the pre-preg module 300. The pre-preg module 300 performs a pre-preg process on the substrate. The conveyor device 700 conveys the pre-preg substrate to the plating module 400. The plating module 400 performs a plating process on the substrate.

[0047] The conveyor device 700 transports the plated substrates to the cleaning module 500. The cleaning module 500 cleans the substrates. The conveyor device 700 transports the cleaned substrates to the spin rinse and dry module 600. The spin rinse and dry module 600 dries the substrates. The conveyor device 700 transfers the dried substrates to the conveyor robot 110. The conveyor robot 110 transports the substrates received from the conveyor device 700 to the cassette at the load port 100. Finally, the cassette containing the substrates is unloaded from the load port 100.

[0048] In addition, Figure 1 、 Figure 2 The structure of the plating device 1000 described in the above is merely an example, and the structure of the plating device 1000 is not limited to the above. Figure 1 、 Figure 2 structure.

[0049] (Structure of the plating module)

[0050] Next, the plating module 400 will be described. In addition, since the plurality of plating modules 400 included in the plating apparatus 1000 according to the present embodiment have the same structure, one plating module 400 will be described.

[0051] Figure 3 Schematic diagram for explaining the structure of the plating module 400 of the plating apparatus 1000 involved in this embodiment. The plating apparatus 1000 and the plating module 400 involved in this embodiment are what are called face-down type, cup type, or horizontal type plating apparatus and plating module. The plating module 400 of the plating apparatus 1000 involved in this embodiment mainly includes a plating tank 10, a substrate holder 30 also called a plating head, a rotating mechanism 40, a tilting mechanism 45, and a lifting mechanism 46. However, the tilting mechanism 45 may also be omitted.

[0052] The plating tank 10 according to this embodiment is composed of a bottomed container with an upper opening. The plating tank 10 has a bottom wall and an outer peripheral wall extending upward from the outer periphery of the bottom wall. The upper portion of the outer peripheral wall is open. Plating solution Ps is stored within the plating tank 10. In this embodiment, the plating tank 10 has a cylindrical shape.

[0053] The plating solution Ps can be any solution containing ions of the metal element that constitutes the plated film, and its specific example is not particularly limited. In this embodiment, a copper plating process is used as an example of a plating process, and a copper sulfate solution is used as an example of a plating solution Ps. In this embodiment, the plating solution Ps contains a predetermined additive. However, this is not limiting, and the plating solution Ps may also be formed without any additives.

[0054] An anode 16 is disposed within the plating tank 10. The specific type of anode 16 is not particularly limited, and either a soluble anode or an insoluble anode can be used. In this embodiment, an insoluble anode is used as the anode 16. The specific type of the insoluble anode is not particularly limited, and platinum, iridium oxide, or the like can be used.

[0055] An overflow tank 20, which is a bottomed container, is provided outside the plating tank 10. The overflow tank 20 temporarily stores the plating solution Ps that exceeds the upper end of the plating tank 10. In one example, the plating solution Ps in the overflow tank 20 is discharged from a discharge port (not shown) for the overflow tank 20, temporarily stored in a storage tank (not shown), and then returned to the plating tank 10.

[0056] A porous resistor 17 is arranged above the anode 16 inside the plating tank 10. Specifically, the resistor 17 is composed of a porous plate component having a plurality of holes (pores). The plating liquid Ps on the lower side of the resistor 17 can pass through the resistor 17 and flow to the upper side of the resistor 17. The resistor 17 is a component provided to achieve uniformity of the electric field formed between the anode 16 and the substrate Wf. By arranging such a resistor 17 in the plating tank 10, it is possible to easily achieve uniformity of the film thickness of the plating film (plating layer) formed on the substrate Wf. In addition, the resistor 17 is not a necessary structure in the present embodiment, and the present embodiment can also be formed into a structure without the resistor 17.

[0057] The substrate holder 30 is a component that holds the substrate Wf, which serves as the cathode. Specifically, the substrate holder 30 is positioned above the anode 16 (and, in this embodiment, above the resistor 17). The substrate holder 30 holds the substrate Wf so that its lower surface Wfa faces the anode 16 and the resistor 17. The lower surface Wfa of the substrate Wf corresponds to the plated surface.

[0058] The substrate holder 30 involved in this embodiment includes a first holding part 31, a second holding part 32, a joint 50 and a sealing part 55. The first holding part 31 and the second holding part 32 are sometimes collectively referred to as a holder body. The substrate holder 30 holds the substrate Wf in a manner in which the substrate Wf is clamped by the first holding part 31 and the second holding part 32. The first holding part 31 holds the upper surface of the substrate Wf. The second holding part 32 holds the outer periphery of the lower surface Wfa of the substrate Wf and has an opening for exposing the plated surface of the substrate Wf. Specifically, the second holding part 32 involved in this embodiment holds the outer periphery of the lower surface Wfa of the substrate Wf via the sealing part 55. When the substrate holder 30 holds the substrate Wf, the sealing part 55 is tightly attached to the substrate Wf, forming a sealed space (internal space) 33 that protects the contact area of the joint 50 and the substrate Wf (the area of the outer periphery of the substrate that contacts the joint 50) from the influence of the plating liquid.

[0059] The substrate holder 30 is connected to the rotating shaft 41 of the rotating mechanism 40. The rotating mechanism 40 is a mechanism for rotating the substrate holder 30. As the rotating mechanism 40, a known mechanism such as a motor can be used. The tilting mechanism 45 is a mechanism for tilting the rotating mechanism 40 and the substrate holder 30. As the tilting mechanism 45, a known tilting mechanism such as a piston cylinder can be used. The lifting mechanism 46 is supported by a support shaft 47 extending in the vertical direction. The lifting mechanism 46 is a mechanism for lifting the substrate holder 30, the rotating mechanism 40, and the tilting mechanism 45 in the vertical direction. As the lifting mechanism 46, a known lifting mechanism such as a direct-acting actuator can be used.

[0060] The connector 50 of the substrate holder 30 is connected to the negative electrode of a DC power supply 90 via wiring (busbars, etc.) within the substrate holder 30, and the anode 16 is connected to the positive electrode of the DC power supply 90 via wiring. The DC power supply 90 allows a direct current or a pulse current to flow as a plating current between the substrate Wf and the anode 16 via the plating solution Ps. The DC power supply 90 is a power supply driven by a constant current.

[0061] During the plating process, the rotation mechanism 40 rotates the substrate holder 30, and the lifting mechanism 46 moves the substrate holder 30 downward, immersing the substrate Wf in the plating solution Ps in the plating tank 10. Furthermore, while the substrate Wf is immersed in the plating solution Ps, the tilting mechanism 45 can also tilt the substrate holder 30 as needed. Next, the DC power supply 90 causes electricity to flow between the anode 16 and the substrate Wf via the plating solution Ps. This forms a plated film on the lower surface Wfa of the substrate Wf.

[0062] The action of plating module 400 is controlled by control module 800. Control module 800 has a microcomputer, and this microcomputer has CPU (Central Processing Unit: central processing unit) 801 as a processor, as a storage unit 802 of non-temporary storage medium etc. Control module 800 makes CPU801 move based on the instruction of the program stored in storage unit 802, thereby controls the controlled part of plating module 400. The program, for example, includes the control of the conveying control of execution conveying robot arm, conveying device, the control of the processing in each processing module, the control of the plating process in plating module, the control of cleaning process, the abnormal program of detecting various equipment. Storage medium can include non-volatile and / or volatile storage medium. As storage medium, for example, known storage medium such as computer-readable ROM, RAM, flash memory or disk-shaped storage medium such as hard disk, CD-ROM, DVD-ROM or floppy disk can be used. Control module 800 is configured to communicate with the unillustrated host controller of unified control plating device and other associated devices, can exchange data between the database possessed with the host controller.A part or all of the functions of control module 800 can also be composed of hardware such as ASIC.A part or all of the functions of control module 800 can also be composed of PLC, sequencer etc.A part or all of control module 800 can be configured in the inside and / or outside of the housing of plating device.A part or all of control module 800 can be connected communicatively with each part of plating device by wired and / or wireless mode.

[0063] (Substrate Holder)

[0064] Figure 4 A portion of the substrate holder 30 is schematically enlarged. Figure 3 A1 section of the sectional view. Figure 3 and Figure 4 , the substrate holder 30 involved in this embodiment is provided with a connector 50 that contacts the contact area of the outer peripheral portion of the lower surface Wfa of the substrate Wf and supplies power to the substrate Wf. Specifically, the connector 50 involved in this embodiment is arranged on the second holding part 32 of the substrate holder 30. A plurality of connectors 50 involved in this embodiment are arranged in the circumferential direction of the substrate holder 30 (specifically, the circumferential direction of the second holding part 32). Each connector 50 has a plurality of (for example, four) plate-shaped electrodes called fingers. The plurality of connectors 50 are evenly arranged in the circumferential direction of the substrate holder 30. In addition, the number of the plurality of connectors 50 is not particularly limited, and in this embodiment, as an example, it is 12. The plurality of connectors 50 and the DC power supply 90 ( Figure 3 ) is electrically connected to supply electricity supplied from the DC power supply 90 to the substrate Wf (more specifically, the seed layer Sd formed on the lower surface Wa of the substrate Wf).

[0065] like Figure 3 and Figure 4 As shown, the plating module 400 according to this embodiment includes a sealing member 55 for preventing the plating solution Ps in the plating tank 10 from contacting the connector 50. The sealing member 55 includes a lip portion 55A that is configured to protrude toward the substrate side, and the lip portion 55A contacts the lower surface Wfa of the substrate Wf. Specifically, the lip portion 55A of the sealing member 55 according to this embodiment is located closer to the inside of the connector 50 (radially inward of the substrate holder 30), and when the substrate Wf is held in the substrate holder 30, it is clamped between the second holding member 32 of the substrate holder 30 and the lower surface Wfa of the substrate Wf. In this example, the lip portion 55A is located near the radially inner end of the sealing member 55. The sealing member 55 has, for example, a ring shape that extends along the outer periphery of the substrate Wf. The plating module 400 includes such a sealing member 55, thereby effectively preventing the plating solution Ps from contacting the connector 50 when the substrate Wf is immersed in the plating solution Ps.

[0066] like Figure 4 As shown, the second holding component 32 of the substrate holder 30 has an outer peripheral wall 32A and a substrate receiving portion 32B protruding radially inward near the lower end of the outer peripheral wall 32A. The sealing component 55 is provided on the substrate receiving portion 32B. The second holding component 32 is a component that holds the sealing component 55, and is therefore also called a sealing ring holder (SRH). In addition, the second holding component 32 may also be a structure assembled from multiple components. For example, the outer peripheral wall 32A and the substrate receiving portion 32B may also be provided separately and combined with each other. The lip 55A contacts the substrate Wf, as shown in FIG. Figure 3As shown, a sealed space (internal space) 33 is formed in the substrate holder 30 to shield and protect the contact portion between the joint 50 and the substrate Wf (a seed layer Sd in a contact region described later) from the plating solution Ps.

[0067] In this embodiment, it is characterized in that Figure 4 As shown in FIG. 1 , the substrate Wf is plated while the contact portion (in this example, the end portion) of the connector 50 that contacts the substrate Wf is covered with liquid 60. The liquid 60 can be pure water, degassed water, or other liquids (liquids used in pre-wetting, pre-soaking, cleaning, etc.). Specifically, a cleaning nozzle 71 (see FIG. 1 ) is provided that can apply pure water without removing the connector 50 from the device after the plating process. Figure 6 ), and a liquid receiving tray 72 for receiving the cleaning drain liquid, a conductivity meter 74 for measuring the conductivity (electrical conductivity) of the cleaning drain liquid is arranged in the liquid receiving tray 72 and / or the cleaning pipe 73 for discharging the cleaning drain liquid, and the cleaning degree of the joint 50 is measured based on the electrical conductivity of the cleaning drain liquid. When the electrical conductivity is lower than a specified threshold value determined by experiments, etc., the supply of cleaning liquid from the cleaning nozzle 71 is stopped. Thus, the contact portion between the joint 50 and the substrate Wf (seed layer Sd) can be covered with a liquid 60 whose electrical conductivity is managed to be lower than a specified threshold value. The electrical conductivity of the liquid 60 corresponds to the electrical insulation performance that does not allow the current to flow between the conductive parts in the internal space 33 through the liquid 60. However, in the case of using the protective electrode described later, the electrical conductivity may also be a degree that allows the anti-corrosion current to flow between the conductive parts such as the seed layer and the joint and the protective electrode. As Figure 4 As shown, even when the substrate Wf is not placed on the sealing ring holder, it is preferable that the end of the connector 50 is always covered with the liquid 60. Therefore, even when the metal from the seed layer Sd adheres to the end of the connector due to repeated use of the connector, the protective electrode described later can be used to always bias the end of the connector toward the low potential side relative to the protective electrode, thereby suppressing the oxidation of the metal attached to the end of the connector and stabilizing the contact resistance over a long period of time.

[0068] During the plating process, the current is allowed to flow between the connector 50 and the substrate Wf while the contact portion between the connector 50 and the substrate Wf is covered with a liquid 60 (e.g., pure water) having an electrical conductivity less than a predetermined threshold. In this embodiment, the liquid 60 covering the contact portion of the connector 50 with the substrate Wf can be retained in the substrate receiving portion 32B. In addition, in this embodiment, the sealing member 55 (in Figure 4The lip 55A in the example shown serves to inhibit or prevent the liquid 60 from dripping radially inward. Furthermore, the outer peripheral wall 32A on the outer circumference of the substrate receiving portion 32B serves to restrict the movement of the liquid 60. Therefore, the substrate receiving portion 32B, the sealing member 55, and the outer peripheral wall 32A of the substrate holder 30 can also constitute a container / reservoir for holding the liquid 60 (however, the liquid 60 does not necessarily need to come into contact with the outer peripheral wall 32A). In other words, the substrate holder 30 has a container / reservoir for holding the liquid 60 within the internal space 33.

[0069] In the experiment conducted by the applicant, in the configuration of this embodiment, the supply of pure water from the cleaning nozzle 71 is 13 mL or more, during which the substrate holder 30 is rotated at least once, and pure water is evenly supplied to the joint 50. The liquid volume of 13 mL is the value obtained by adding the amount of pure water required to completely wet the contact part of one finger of the joint 50 that contacts the substrate Wf (seed layer Sd) to the amount of 12 joints (the amount of one week of substrate Wf1). In other words, it is the amount of pure water required to completely wet the contact parts of all joints 50 of the substrate holder 30 that contact the substrate Wf. According to the experiments conducted by the applicant, it can be seen that when the conductivity of the liquid (coating liquid) 60 is made less than 50 μS / cm, the seed layer Sd of the substrate Wf will not be damaged (refer to International Patent Application No. 2021 / 038404). Specifically, after cleaning the connector 50, the cleaning liquid (e.g., pure water) adhering to the connector 50 is not removed, and the cleaning liquid, whose conductivity is controlled below a predetermined threshold, is directly used as a coating liquid (coating water) for the connector-substrate contact area for the next substrate processing. This eliminates the need to dry the connector and prevents plating from occurring while the connector 50 and substrate Wf are not fully wetted.

[0070] In addition, in other experiments conducted by the applicant, it is known that when a protective electrode for corrosion protection of the seed layer described later is provided, even if the conductivity of the liquid 60 is increased within a range below 1000 μS / cm, the seed layer Sd of the substrate Wf will not be damaged. Therefore, by providing the protective electrode described later, the management of the conductivity of the coating liquid can be greatly relaxed. In addition, it is known that due to the influence of the deslagging treatment before plating, when using a certain specific substrate whose seed layer surface is covered with a thick oxide film, even if the conductivity is below 50 μS / cm, there are cases where corrosion is more severe than usual. This can be considered to be that when the joint 50 is brought into contact with the seed layer Sd, by pressing the joint with a force greater than a certain amount, the oxide film on the surface of the seed layer and a portion of the seed layer are shaved off, exposing the metal surface, thereby reducing the contact resistance. However, when the seed layer surface is covered with a thick oxide film, the corrosion site is only concentrated near the joint where the metal surface is exposed, and the corrosion is more severe than usual. Even in such a case, by providing the protective electrode described later, corrosion can be effectively suppressed.

[0071] When a guard electrode described later is used, the range of the electrical conductivity of the liquid 60 is greatly relaxed, and thus management of the electrical conductivity of the liquid 60 using a conductivity meter or the like can be omitted.

[0072] In addition, in the present embodiment, the contact area (the area in contact with the connector 50) of the substrate Wf wetted in the pre-treatment such as the pre-wetting treatment is not dried until the plating is completed. Thus, the following undesirable conditions can be suppressed or prevented. If the contact area of the substrate wetted in the pre-treatment is dried, water will leak into the surrounding pattern openings, and bubbles may remain in the pattern openings during plating, causing an abnormality in which the portion is not plated. In addition, the surface of the seed layer in the contact area of the incompletely dried substrate may be oxidized, causing poor conduction. In addition, if the contact portion between the seed layer of the substrate and the connector is not completely wetted, the seed layer Sd may be dissolved due to the local battery effect caused by dissolved oxygen and / or shunt current (shunt current between the connector 50 and the seed layer Sd via liquid flow outside the contact portion between the connector 50 and the seed layer Sd of the substrate Wf), resulting in power supply deviation and reducing the in-plane uniformity of the coating thickness.

[0073] (Principle of seed layer corrosion)

[0074] Figure 20 This is an illustration of the dissolution of the seed layer caused by the local cell effect caused by dissolved oxygen. Consider a sealed space 33 ( Figure 3 ) is mixed with liquid Q in the plating solution. At this time, as shown in the figure, oxygen O2 in the air dissolves into liquid Q, and Cu in the seed layer Sd transfers electrons to O2, which becomes OH. － , and Cu becomes Cu2+ , a local battery effect of dissolution into liquid Q is generated, and the seed layer Sd dissolves. Through this reaction, Cu dissolves from the seed layer Sd, the seed layer Sd becomes thinner, and the resistance of the seed layer Sd increases, which may cause power supply deviation. This phenomenon is caused by the fact that the gas-liquid interface is close to the seed layer Sd. In addition, when the resistance value of the seed layer Sd becomes high due to the corrosion of the seed layer Sd caused by the local battery effect, the dissolution of the seed layer Sd caused by the shunt current described later is also likely to occur, and the dissolution of the seed layer Sd further proceeds.

[0075] Figure 21 It is an explanatory diagram for explaining the dissolution of the seed layer caused by the shunt current. Figure 22 is an equivalent circuit diagram illustrating the shunt current. In the figure, I total is the total current flowing through the connector, I cw is the current flowing through the contact area between the seed layer and the joint, I shunt is the shunt current. R contact is the contact resistance between the contact 50 and the seed layer Sd, R wafer is the resistance of the seed layer Sd, R dissolution is the resistance of the dissolved site on the seed layer side of the shunt current path, R deposition is the resistance of the deposited portion on the connector side of the shunt current path, R electrolyte Indicates the resistance of the plating solution.

[0076] When the contact portion between the connector 50 and the seed layer Sd in the sealed space 33 is covered by a liquid Q with high conductivity (for example, a plating solution or a liquid mixed with the plating solution), the resistance R wafer and / or the contact resistance R between the connector 50 and the seed layer Sd contact When the current is high, due to the ionic conduction in the liquid Q and the redox reaction on the surface of the seed layer Sd and the surface of the joint 50, a shunt current I flows from the seed layer Sd through the liquid Q to the joint 50. shunt (The current I passing through the contact part cw Shunt current I shunt On the surface of the seed layer Sd, Cu becomes Cu 2+ And dissolve into liquid Q, the Cu in liquid Q 2+ It flows as Cu on the surface of the connector 50. Therefore, when a shunt current is generated, the Cu in the seed layer Sd dissolves, thinning the seed layer Sd and increasing the resistance of the seed layer Sd, potentially causing power supply deviation. This shunt current is also generated when the resistance of the seed layer Sd increases locally due to the local battery effect described above.

[0077] As described above, by covering the contact area between the connector and the seed layer with a liquid having a conductivity of 50 μS / cm or less, the corrosion (dissolution) of the seed layer caused by local battery action and / or shunt current can be effectively suppressed. In addition, by using a protective electrode (described later), even if the conductivity of the coating liquid covering the contact area between the connector and the seed layer is increased to 1000 μS / cm, the corrosion (dissolution) of the seed layer caused by local battery action and / or shunt current can be effectively suppressed.

[0078] Figure 5 、 Figure 6 The control method of the plating apparatus according to the present embodiment will be described with reference to these figures.

[0079] In step S11, a pre-wetting process is performed on the substrate Wf having the seed layer Sd provided on the surface to be plated in the pre-wetting module 200. In the pre-wetting process, the surface to be plated of the substrate before the plating process is wetted with a process liquid Lp1 such as pure water or degassed water, and the air inside the resist pattern Rp formed on the surface of the substrate is replaced with the process liquid Lp1. After the pre-wetting process, the substrate Wf is wetted with the process liquid Lp1, and the openings of the resist pattern Rp on the surface of the substrate Wf are filled with the process liquid Lp1 ( Figure 5 ).

[0080] In step S12, in the prepreg module 300, the substrate Wf is subjected to a prepreg treatment. In addition, the prepreg treatment is sometimes omitted. In the prepreg treatment, for example, a treatment liquid Lp2 such as sulfuric acid or hydrochloric acid is used to etch away the oxide film with high resistance existing on the surface of the seed layer Sd formed on the plated surface of the substrate Wf before the plating treatment, thereby cleaning or activating the plated base surface. In addition, after the prepreg treatment, the substrate Wf can also be cleaned with a treatment liquid Lp3 such as pure water or degassed water. The substrate Wf after the prepreg treatment is wetted by the treatment liquid Lp2 (or Lp3), and the opening of the resist pattern Rp on the surface of the substrate Wf is filled with the treatment liquid Lp2 (or Lp3) ( Figure 5 In the following description, the processing liquids Lp1, Lp2, and Lp3 are sometimes collectively referred to as the processing liquid Lp.

[0081] In step S13, the substrate Wf conveyed to the plating module 400 is mounted on the substrate holder 30, which is also called a plating head. Figure 5As shown, the substrate Wf is wetted with the processing liquid Lp (Lp1, Lp2, or Lp3). The contact portion 51 of the joint 50 of the substrate holder 30 is covered with the coating liquid of the liquid 60 supplied during the cleaning process of steps S15 and / or S17 described later. In addition, the contact portion 51 of the joint 50 represents the portion of the joint 50 that contacts the seed layer Sd of the substrate Wf (in this example, the end portion of the joint 50).

[0082] In step S14, the substrate Wf held by the substrate holder 30 is immersed in the plating solution Ps in the plating tank 10, and the plating process is performed on the substrate Wf. Figure 5 In step S14 , the resist pattern Rp of the substrate Wf is omitted. At this time, the contact portion between the joint 50 of the substrate holder 30 and the substrate Wf and a portion of the protective electrode (described later) are covered with the liquid 60 .

[0083] In step S15, after the plating process, the substrate holder 30 is raised to above the liquid level of the plating solution Ps in the plating tank 10, and the plated surface of the substrate Wf is cleaned with the cleaning liquid supplied from the cleaning liquid nozzle 61. Figure 6 ). At this time, the substrate holder 30 and / or the cleaning liquid nozzle 61 can also be rotated to uniformly apply the cleaning liquid to the substrate Wf. Through this cleaning process, the plating liquid attached to the substrate Wf can be recovered and properly reused, and / or by wetting the plated surface of the substrate Wf, the plated surface can be prevented from drying. The cleaning liquid can be, for example, pure water, degassed water, or other liquids (liquids used in pre-wetting, pre-soaking, cleaning, etc.). The cleaning liquid used in the cleaning is recovered to the liquid receiving tray 62 arranged below the substrate Wf and discharged via the drainage pipe 63. A conductivity meter 64 can also be provided on the liquid receiving tray 62 and / or the drainage pipe 63 to measure the conductivity of the recovered cleaning liquid (pure water). In addition, the recovered cleaning liquid can be returned to the plating tank 10 and reused after or without concentration adjustment. For example, the cleaning nozzle 61 and the liquid receiving tray 62 can be configured to move to the bottom of the substrate holder 30 when the substrate holder 30 is raised, and to be able to retract from the bottom of the substrate holder 30 after the cleaning process.

[0084] In step S16, the substrate Wf is removed from the substrate holder 30. The removed substrate Wf is sequentially transported to the cleaning module 500 and the spin rinse and dry module 600, and after being cleaned and dried, is transported to the cassette of the load port 100 (step S18).

[0085] In step S17, the joint 50 and the sealing component 55 of the substrate holder 30 after the substrate Wf is removed are cleaned using a prescribed amount of cleaning liquid 60 supplied from the cleaning nozzle 71. At this time, the substrate holder 30 is rotated at least once to evenly supply pure water to the joint 50. In addition, if pure water is supplied to the joint 50 at least once, the cleaning nozzle 71 can also be rotated, or both the substrate holder 30 and the cleaning nozzle 71 can be rotated. In this embodiment, by wetting both the substrate Wf side and the substrate holder 30 side, it is possible to ensure that the contact portion between the joint 50 and the substrate seed layer Sd is covered with a sufficient amount of water. The cleaning liquid 60 can be, for example, pure water, degassed water, or other liquids (liquids used in pre-wetting, pre-soaking, cleaning, and other processes). The cleaning liquid 60 used in cleaning is recovered to the liquid receiving tray 72 arranged below the substrate Wf and discharged through the drain pipe 73. A conductivity meter 74 is provided on the liquid receiving tray 72 and / or the drainage pipe 73, and the conductivity of the recovered cleaning liquid (pure water) is measured by the conductivity meter 74. The conductivity measured by the conductivity meter 74 is provided to the control module 800. The control module 800 determines whether the measured conductivity of the cleaning liquid is less than a threshold value. If the control module 800 determines that the conductivity of the cleaning liquid is greater than the threshold value, the control module 800 continues the cleaning process. On the other hand, if the control module 800 determines that the conductivity of the cleaning liquid is less than the threshold value, the control module 800 returns to step S13 and waits until the next substrate Wf is moved into the plating module 400 and the next substrate Wf is installed on the substrate holder 30.

[0086] The above process is repeated to sequentially plate multiple substrates Wf. Furthermore, when the initial substrate Wf is plated, or when a certain amount of time has passed since a previously plated substrate Wf was removed from the plating module 400, there is a possibility that the contact portion 51 of the connector 50 of the substrate holder 30 may be dry or incompletely dry. Furthermore, as time passes since cleaning is completed, atmospheric carbon dioxide gradually dissolves into the cleaning liquid on the substrate holder, increasing the conductivity and possibly exceeding the threshold. In such cases, before plating the substrate Wf, step S17 is performed to cover the contact portion 51 of the connector 50 of the substrate holder 30 with liquid 60, and then the moistened substrate Wf is mounted on the substrate holder 30 in step S13.

[0087] In this embodiment, if Figure 6As shown, the liquid 60 for covering the contact portion of the connector 50 that is in contact with the substrate Wf can be retained in the substrate receiving portion 32B. In addition, in the present embodiment, the sealing component 55 (lip 55A) plays a role in suppressing or preventing the liquid 60 from dripping radially inward. In addition, on the outer peripheral side of the substrate receiving portion 32B, the outer peripheral wall 32A plays a role in limiting the movement of the liquid 60. Therefore, the substrate receiving portion 32B, the sealing component 55 and the outer peripheral wall 32A of the substrate holder 30 can also constitute a container portion / storage portion for retaining the liquid 60 (however, the liquid 60 may not be in contact with the outer peripheral wall 23A). That is, the sealed space (internal space) 33 has a container portion / storage portion for retaining the liquid 60. In other words, the holder body (first holding component 31, second holding component 32) has a container portion / storage portion for retaining the liquid 60 or a sealed space (internal space) 33.

[0088] (Guard electrode)

[0089] It is known through experiments that: in the sealed space 33 of the substrate holder 30, in a state where at least the contact portion between the connector 50 and the seed layer Sd is immersed in liquid, the plating of the substrate Wf (wet contact method) is carried out. As described above, if the conductivity of the liquid (for example, pure water) is managed to be below 50μS / cm, the local battery action and the shunt current can be suppressed, thereby suppressing or preventing the corrosion of the seed layer Sd. In the structure of this embodiment, it is known that by further providing the protective electrode (also called the anti-corrosion electrode) described later, even if the conductivity of the liquid covering the connector 50 is expanded to a range below 1000μS / cm, the corrosion of the seed layer Sd of the substrate Wf can be suppressed or prevented. That is, in the wet contact method, by providing the protective electrodes 238A, 238B ( Figure 7 、 Figure 9 ) is immersed in the liquid and arranged near the seed layer Sd, which can effectively suppress the corrosion of the seed layer Sd even when the electrical conductivity of the liquid is high (including the case where a small amount of plating liquid invades the sealed space).

[0090] (External power supply type)

[0091] Figure 7 It is a cross-sectional view schematically showing an enlarged portion of the substrate holder 30 including a protective electrode 238A according to an example. Figure 8 This figure shows a top view of the second holding member 32 of a substrate holder 30 having a guard electrode 238A according to an example. In this example, by biasing the guard electrode 238A toward a higher potential relative to the seed layer Sd, the guard electrode 238A functions as an anode and the seed layer Sd functions as a cathode, thereby suppressing corrosion of the seed layer Sd. In this figure, the connector 50 is shown as being powered via a bus bar 49 disposed within the substrate holder 30.

[0092] In this embodiment, the guard electrode 238A is disposed between the connector 50 and the guard electrode 238A via an insulating spacer 239. The spacer 239 is a structure for electrically isolating the guard electrode 238A from the connector 50. If the guard electrode 238A and the connector 50 are separated and arranged in a manner that ensures electrical insulation between the two, the spacer 239 may be omitted, or any other method may be used to ensure electrical insulation between the two. Furthermore, separation using the spacer 239 is effective in ensuring electrical insulation between the guard electrode 238A and the connector 50 within a confined space such as the internal space 33 of the substrate holder 30.

[0093] (External power supply type, insoluble protective electrode)

[0094] The protective electrode 238A is, for example, an insoluble electrode formed of a material having a natural potential (standard electrode potential) greater (higher) than that of the material of the seed layer Sd, or coated with such a material. A material having a natural potential greater than that of the material of the seed layer Sd refers to a material that is less likely to become an anode (easier to become a cathode) than the seed layer Sd when the seed layer Sd and the protective electrode 238A are immersed in the liquid 60. In addition, the material of the protective electrode 238A is preferably a stable material in which the oxygen overvoltage when oxygen is generated due to the electrode reaction when biased to the high potential side is not too large, and the material components do not dissolve or corrode. The material of the protective electrode 238A can use a material that is generally used as an insoluble electrode for oxygen generation, for example, Pt, Pt / Ti, Pt / SUS, IrO2 / Ti.

[0095] From the viewpoint of suppressing the corrosion of the seed layer Sd, the protective electrode 238A is preferably arranged near the seed layer Sd (contact area) at the periphery (edge portion) of the substrate Wf where the possibility of corrosion is high, such as Figure 8 As shown, the protective electrode 238A is substantially positioned opposite the entire perimeter of the substrate Wf. The distance between the protective electrode 238A and the edge of the substrate Wf is preferably, for example, 10 mm or less. In this figure, the protective electrode 238A is formed continuously along the entire perimeter of the substrate Wf (the entire perimeter of the substrate holder 30), but it can also be provided in sections corresponding to the various sections of the connector 50. The outer perimeter (edge portion) of the substrate Wf refers to, for example, the portion of the substrate positioned within the sealed space 33 when the substrate Wf is held by the substrate holder 30.

[0096] like Figure 7As shown, the protective electrode 238A is configured so that at least a portion thereof is in contact with the liquid 60 or immersed in the liquid 60. In addition, the protective electrode 238A is connected to the positive electrode of the DC power supply 236, and the connector 50 (seed layer Sd) is connected to the negative electrode of the DC power supply 236 via the bus 49. Thus, by biasing the protective electrode 238A to the high potential side relative to the seed layer Sd, the protective electrode 238A functions as an anode and the seed layer Sd functions as a cathode, thereby suppressing the oxidation reaction of Cu in the seed layer Sd and suppressing the corrosion (dissolution) of the seed layer Sd. The DC power supply 236 is a bias power supply driven by a constant voltage or a constant current, as long as a voltage of about 2V can be applied between the protective electrode 238A and the seed layer Sd. In one example, the DC power supply 236 can use a 1.5V dry cell. As a DC power supply, a voltage regulator commonly used for electroplating equipment, etc. can also be used. The voltage regulator can be pre-set to an upper limit voltage value and an upper limit current value, and a constant voltage drive is performed below the upper limit current value, and when the upper limit current value is reached, it is switched to a constant current drive. Thus, when the conductivity of the liquid 60 rises sharply due to leakage of the plating solution, it is possible to prevent the flow of more than necessary current. The voltage of the protective electrode 238A relative to the seed layer Sd is preferably a voltage that is sufficiently greater than the difference between the natural potential of the seed layer Sd and the protective electrode 238A. For example, the natural potential difference between copper and platinum in a 0.1% dilution (with a conductivity of approximately 1000 μS / cm) of a copper sulfate plating solution (copper is 50 g / L, sulfuric acid is 100 g / L, and chlorine is 50 mg / L) is approximately 0.5 V. Therefore, when the material of the seed layer Sd is copper and the material of the protective electrode 238A is platinum, it is preferably applied with a voltage that is sufficiently greater than 0.5 V.

[0097] Figure 11 This is an explanatory diagram for explaining the principle of using a protective electrode to prevent corrosion of the seed layer. The mechanism of using the insoluble protective electrode 238A to prevent corrosion is as follows. In the liquid 60, near the protective electrode 238A, 2H2O → O2 + 4H + On the other hand, in the liquid 60, near the seed layer Sd, O2+4H + +4e→2H2O (production of water), 2H + +2e→H2 (production of hydrogen), Cu 2+ +2e→Cu reduction reaction (when the plating solution is mixed into the liquid 60). In this way, the corrosion of the seed layer Sd is suppressed or prevented by the protective electrode 238A.

[0098] That is, even if a gradient of dissolved oxygen concentration ( Figure 20), by making the protective electrode 238A function as an anode and the seed layer Sd function as a cathode, the oxidation reaction of Cu in the seed layer Sd can be suppressed, and the corrosion of the seed layer Sd caused by the local battery effect can be suppressed or prevented. Therefore, the corrosion of the seed layer Sd can be suppressed or prevented, and the reduction in the uniformity of the plating film thickness can be suppressed or prevented.

[0099] In addition, even if the plating solution is mixed into the liquid 60 due to leakage of the plating solution into the internal space 33, the oxidation reaction of Cu in the seed layer Sd can be suppressed by making the protective electrode 238A function as an anode and the seed layer Sd function as a cathode, and the oxidation reaction of Cu in the seed layer Sd can be suppressed or prevented due to the local battery action ( Figure 20 ) and shunt current ( Figure 21 ) caused by the corrosion of the seed layer Sd. Therefore, the corrosion of the seed layer Sd can be suppressed or prevented, and the reduction in the uniformity of the plating film thickness can be suppressed or prevented. In addition, when an oxide film exists on the surface of the seed layer Sd, the oxide film can be reduced to metal by applying a sufficiently large voltage (for example, 4V or more) between the protective electrode 238A and the connector 50. Thus, even when a specific substrate is used in which the surface of the seed layer is covered with a thick oxide film (for example, a thickness of 50nm), the contact resistance can be stabilized, and the corrosion of the seed layer can be prevented from concentrating near the connector, so that the corrosion of the seed layer can be more effectively suppressed. For example, when such a substrate is used, a large voltage can be applied before plating or at the beginning of plating to reduce the oxide film on the surface of the seed layer, and then the voltage can be reduced to a voltage sufficient to prevent the corrosion of the seed layer for plating. In addition, similar to the oxide film on the surface of the seed layer, even when an oxide film exists at the end of the connector, it can be reduced to metal. For example, it is effective when metal from the seed layer adheres to the end of the connector and oxidizes due to long-term use. This operation can be performed even when the substrate Wf is not present, and can therefore be performed during idle operation when no plating is being performed, etc. By reducing the oxide film at the terminal end of the contact, the contact resistance increased by the oxide film formation can be improved.

[0100] (External power supply type, soluble protective electrode)

[0101] As the material of the protective electrode 238A, a material having a natural potential (standard electrode potential) that is the same as that of the material of the seed layer Sd can also be used. In this case, the protective electrode 238A is biased toward the high potential side relative to the seed layer Sd by the DC power supply 236, so that the protective electrode 238A is dissolved in preference to the seed layer Sd, so that the protective electrode 238A functions as a sacrificial electrode (soluble electrode). The material of the protective electrode 238A can be, for example, the same material as the seed layer Sd. The material of the protective electrode 238A can use a conductor of the same material as the plated metal, for example, an electrode composed of phosphorus copper can be used, similar to the soluble anode. In addition, as the material of the protective electrode 238A, a material having a natural potential that is smaller (lower) than that of the seed layer Sd can also be used. In this case, it can be considered that the protective electrode 238A is more easily dissolved, and its function as a sacrificial electrode is improved.

[0102] The mechanism of preventing corrosion by utilizing the solubility of the protective electrode 238A is as follows. Figure 11 As shown, in the liquid 60, near the soluble guard electrode 238A, M→M n+ +ne (e.g., Cu → Cu n+ On the other hand, in the liquid 60, near the seed layer Sd, O2+4H + +4e→2H2O (production of water), 2H + +2e→H2 (production of hydrogen), Cu 2+ +2e→Cu reduction reaction. In this way, the soluble guard electrode 238A dissolves prior to Cu in the seed layer Sd, and corrosion of the seed layer Sd can be suppressed or prevented.

[0103] That is, even if a gradient of dissolved oxygen concentration ( Figure 20 ), the soluble protective electrode 238A dissolves preferentially over the seed layer Sd, thereby suppressing or preventing corrosion of the seed layer Sd caused by local battery action. Therefore, corrosion of the seed layer Sd can be suppressed or prevented, and a decrease in the uniformity of the coating thickness can be suppressed or prevented.

[0104] Furthermore, even if the plating solution is mixed into the liquid 60 due to leakage of the plating solution into the internal space 33, the soluble protective electrode 238A dissolves preferentially over the seed layer Sd, thereby suppressing or preventing the local battery effect ( Figure 20 ) and shunt current ( Figure 21 ) causes corrosion of the seed layer Sd. Therefore, the corrosion of the seed layer Sd can be suppressed or prevented, and the reduction in uniformity of the plating film thickness can be suppressed or prevented.

[0105] (Leak Detection)

[0106] In either the insoluble or soluble guard electrode 238A, a current detector 237 may be provided within the DC power supply 236A or on the wiring from the DC power supply 236A. In this state, the control module 800 monitors the current flowing between the guard electrode 238A and the connector 50 (or bus bar 49), or the resistance therebetween. The current flowing between the guard electrode 238A and the connector 50 (or bus bar 49) is equivalent to the current flowing through the liquid 60 within the internal space 33. The resistance between the guard electrode 238A and the connector 50 (bus bar 49) is equivalent to the resistance of the liquid 60 within the internal space 33.

[0107] The application of the DC voltage to the guard electrode 238A and the detection of the current (resistance) are controlled by the control module 800. The control module 800 obtains the current flowing in the guard electrode 238A (the current flowing in the liquid 60 in the internal space 33) through the current detector 237, and detects leakage of the plating solution into the internal space 33 based on this current. Alternatively or in addition to this, the control module 800 obtains the current flowing in the guard electrode 238A, calculates the resistance value of the liquid 60 based on the voltage between the guard electrode 238A and the connector 50 (busbar 49) and the detected current, and detects leakage based on the resistance value.

[0108] When the plating solution does not leak into the internal space 33, the resistance of the liquid 60 in the internal space 33 is extremely high, so no current flows between the guard electrode 238A and the connector 50 (busbar 49). Alternatively, an anti-corrosion current due to the water decomposition reaction and hydrogen generation reaction flows from the guard electrode 238A to the connector 50 (busbar 49), but this current is very small compared to the current that would flow if the plating solution leaked. On the other hand, if leakage occurs, the plating solution mixes with the liquid 60, causing the resistance of the liquid 60 to decrease, and current flows (or increases) between the guard electrode 238A and the connector 50 (busbar 49). In this way, leakage of the plating solution into the internal space 33 can be detected via the guard electrode 238A.

[0109] In this structure, by monitoring the electric current (resistance) between the guard electrode 238A and the joint 50 (busbar 49), it is possible to detect in advance whether the plating solution leaks to the inner space 33. Therefore, even if leakage of plating solution occurs, it is also possible to detect in advance the leakage of plating solution by the guard electrode 238A, detect in advance the abnormality of the substrate holder 30 and the replacement period of the seal. In addition, in the event of leakage of the plating solution of the amount that the seed layer Sd may corrode, the dissolution of Cu is also suppressed by the guard electrode 238A as mentioned above, so as to suppress or prevent the corrosion of the seed layer. Therefore, it is possible to detect in advance the leakage of plating solution, thereby suppressing or preventing the reduction of the uniformity of the coating thickness. It is also possible to divide the guard electrode 238A into a plurality of configurations in a manner corresponding to each block of the joint 50, each of which is connected to a separate DC power supply 236 and a current detector 237, and perform the application of DC voltage and leakage detection of the plating solution. This allows the occurrence site of plating solution leakage to be identified to a certain extent, and by individually controlling the anti-corrosion current flowing through each block, corrosion of the seed layer Sd can be more effectively suppressed even when plating solution leakage occurs.

[0110] In addition, Figure 7 In the present invention, a DC voltage based on a DC power supply 236 is applied between the protective electrode 238A and the connector 50 (busbar 49), and the DC current is detected by a current detector 237. However, an AC power supply can also be used instead of the DC power supply 236, and the AC current or impedance between the protective electrode 238A and the connector 50 (busbar 49) is monitored by the current detector to detect leakage.

[0111] Alternatively, the current detector 237 (leakage detection) may be omitted, and the guard electrode 238A may be used only as an electrode for preventing corrosion of the seed layer.

[0112] (Direct connection type, soluble guard electrode)

[0113] Figure 9 1 is a cross-sectional view schematically showing an enlarged portion of a substrate holder 30 including a protective electrode 238B according to another example. Figure 102 is a top view of the second holding component 32 of the substrate holder 30 having a protective electrode 238B according to another example. In this example, an electrode made of a material that is easier to become an anode than the material of the seed layer Sd (a material with a small (low) natural potential) is used as a sacrificial electrode as the protective electrode 238B. In this example, by utilizing the difference in natural potential between the protective electrode 238B and the seed layer Sd, the protective electrode 238A functions as an anode and the seed layer Sd functions as a cathode, thereby suppressing the oxidation reaction of Cu in the seed layer Sd and suppressing the corrosion (dissolution) of the seed layer. In this figure, the connector 50 is shown as a structure in which power is supplied via a busbar 49 arranged in the substrate holder 30.

[0114] like Figure 9 As shown, the protective electrode 238B is electrically connected to the connector 50 by being fixed thereto, and is electrically connected to the seed layer Sd via the connector 50. The protective electrode 238B is a soluble electrode formed from a material with a lower natural potential (standard electrode potential) than the material of the seed layer Sd. A material with a lower natural potential than the material of the seed layer Sd means a material with a lower natural potential than the material of the seed layer Sd and a material that is more likely to become an anode than the seed layer Sd. In the case where the seed layer Sd is Cu, the material of the protective electrode 238B can be selected from, for example, Al, Zn, Fe, etc. Among them, the natural potential of Zn in a 0.1% dilution (conductivity of approximately 1000 μS / cm) of a copper sulfate plating solution (50 g / L copper, 100 g / L sulfuric acid, and 50 mg / L chlorine) is the lowest (approximately -1.1 V relative to Cu), and the corrosion inhibition effect of the seed layer is the highest. In addition, the protective electrode 238B can also be electrically connected to the seed layer Sd via a conductor other than the connector 50, and can also be electrically connected to the connector 50 via a conductor other than the connector 50. Alternatively, a structure may be employed in which the protective electrode 238B is in direct contact with and electrically connected to the seed layer Sd when the substrate Wf is held by the substrate holder 30. When the protective electrode 238B is directly fixed to the connector 50 as in this embodiment, the structure for arranging the protective electrode 238B within the sealed space 33 can be simplified.

[0115] From the viewpoint of suppressing the corrosion of the seed layer Sd, the protective electrode 238B is preferably arranged near the seed layer Sd (contact area) at the periphery (edge portion) of the substrate Wf where the possibility of corrosion is high, such as Figure 10 As shown, the protective electrode 238B is substantially positioned opposite the entire perimeter of the substrate Wf. The distance between the protective electrode 238B and the edge of the substrate Wf is preferably, for example, 10 mm or less. In this figure, the protective electrode 238B is provided in sections corresponding to the respective sections of the connector 50. However, it may be provided continuously along the entire perimeter of the substrate Wf (the entire perimeter of the substrate holder 30).

[0116] like Figure 9 As shown, the protective electrode 238B is configured so that at least a portion thereof is in contact with or immersed in the liquid 60 (pure water, etc.). The protective electrode 238B has a lower natural potential than the seed layer and is electrically connected to the seed layer Sd via the connector 50. Therefore, it functions as a sacrificial electrode that dissolves before the seed layer Sd and functions as an anti-corrosion electrode (anti-corrosion electrode) that suppresses corrosion of the seed layer Sd.

[0117] The mechanism of preventing corrosion by using the protection electrode 238B having a lower natural potential than the seed layer Sd is equivalent to Figure 11 In the embodiment, the DC power supply 236 is omitted and the protection electrode 238A is short-circuited with the connector 50. Figure 11 As shown, in the liquid 60, near the guard electrode 238B, M→M n+ +ne (e.g., Al→Al 3+ +3e) oxidation reaction, the material M of the protective electrode 238B is dissolved in the liquid 60. On the other hand, in the liquid 60, near the seed layer, O2+4H + +4e→2H2O (production of water), 2H+2e→H2 (production of hydrogen), Cu 2+ +2e→Cu reduction reaction (when the plating solution is mixed into the liquid 60). In this way, the protective electrode 238B dissolves before the seed layer Sd, thereby suppressing or preventing corrosion of the seed layer Sd.

[0118] That is, even if a gradient of dissolved oxygen concentration ( Figure 20 ), the soluble protective electrode 238B dissolves preferentially over the seed layer Sd, thereby suppressing or preventing corrosion of the seed layer Sd caused by local battery action. Therefore, corrosion of the seed layer Sd can be suppressed or prevented, and a decrease in the uniformity of the coating thickness can be suppressed or prevented.

[0119] In addition, even if the plating solution is mixed into the liquid 60 due to leakage of the plating solution into the internal space 33, the soluble protective electrode 238B is dissolved in priority to the seed layer Sd, which can suppress or prevent the local battery effect ( Figure 20 ) and shunt current ( Figure 21 ) causes corrosion of the seed layer Sd. Therefore, the corrosion of the seed layer Sd can be suppressed or prevented, and the reduction in uniformity of the plating film thickness can be suppressed or prevented.

[0120] The protective electrode 238B of this embodiment eliminates the need for an external power source to bias the protective electrode 238B, thereby simplifying the structure of the plating module. Furthermore, the surface of the protective electrode 238B is preferably covered with an anode bag, a diaphragm, or the like. This prevents oxides and hydroxides generated on the surface of the protective electrode 238B during corrosion from falling off the electrode surface and contaminating the interior of the substrate holder 30.

[0121] (Electrical test model)

[0122] Figure 12 Schematic diagram showing a current-carrying test model used to test the effectiveness of protective electrodes. Figure 13 This is a photo showing the structure of the power-on test model. Figure 14 This is a magnified photo of a portion of the energized test model. In this energized test model, Figure 12 As shown, an insoluble protective electrode 238A is used, and the protective electrode 238A is biased toward the high potential side relative to the connector 50 (seed layer Sd) by a DC power supply 236. In addition, in the power-on test, a Pt wire (diameter 0.4 mm) is used as the protective electrode 238A. In addition, a power-on test is implemented by causing a current corresponding to the plating current to flow between the connector 50 and the portion of the seed layer Sd away from the connector 50 by a DC power supply 90. That is, instead of causing the plating current to flow between the seed layer Sd of the substrate Wf and the anode 16 ( Figure 3 ) between the contact 50 and the shield electrode 238A, and a current simulating the plating current flows between the portion of the seed layer Sd connected to the connector 50 and the portion away from the connector 50, thereby performing an electric current test that models the plating process. Furthermore, a blank wafer (a type of wafer) without a pattern such as a resist pattern is used as the substrate Wf. The electric current test is performed by covering the contact portion between the connector 50 and the seed layer Sd and a portion of the shield electrode 238A with the liquid 60.

[0123] Figure 13 and Figure 14 The following are photos of an actual power-on test model. As shown in these figures, a blank wafer serving as a substrate Wf is clamped and fixed from above and below by a fixture 901, with one end of the substrate Wf in contact with a connector 50. The connector 50 is held by a fixture 902. The other end of the substrate Wf and the connector 50 are connected to the positive and negative poles of a DC power supply 90, respectively. Figure 14 As shown, a protective electrode 238A composed of a Pt wire is arranged below the connector 50. One end of the Pt wire is bent into an L shape and led upward from the gap of the connector 50. Figure 13 As shown, the lead-out portion of the guard electrode 238A and the connector 50 are respectively connected to the positive and negative electrodes of the DC power supply 236. The gap 903 between the jig 901 and the jig 902 is filled with the liquid 60 (pure water in this example).

[0124] In addition, as a comparison, Figures 12 to 14 In the configuration of the current-carrying test model shown, a current-carrying test was also performed in a configuration in which the guard electrode 238A was omitted. Figure 15 This is a photo showing the results of a current-carrying test with a guard electrode installed. Figure 16 These are photos showing the results of the power-on test without the protection electrode. As can be seen from these figures, corrosion occurs in the seed layer Sd without the protection electrode. Figure 16 ), but by providing the protection electrode 238A, the corrosion of the seed layer Sd can be suppressed ( Figure 15 ).

[0125] (Second embodiment)

[0126] Figure 17 : This is a schematic diagram for illustrating the structure of the plating module of the plating device involved in the second embodiment. The plating module of this embodiment is a vertical (also known as immersion type, panel type) plating module that plates the substrate in a vertical position. As shown in the figure, the plating module 400 includes: a plating tank 10, which holds the plating solution inside; and an anode 16, which is arranged opposite to the substrate holder 30 in the plating tank 10. The anode 16 is held by the anode holder 60 and arranged in the plating tank 10. The substrate holder 30 is configured to hold a substrate Wf such as a wafer in a removable manner and immerse the substrate Wf in the plating solution Ps in the plating tank 10. The anode 16 is connected to the positive pole of the DC power supply 90 via the anode holder 60, and the substrate Wf is connected to the negative pole of the DC power supply 90 via the substrate holder 30. When a voltage is applied between the anode 16 and the substrate Wf, current flows through the substrate Wf, and a metal film is formed on the surface of the substrate Wf in the presence of the plating solution. The substrate Wf may be circular, quadrilateral, other polygonal, or any other arbitrary shape.

[0127] The plating module 400 also includes an overflow tank 20 adjacent to the plating tank 10. The plating liquid in the plating tank 10 flows over the side wall of the plating tank 10 and into the overflow tank 20. The plating liquid Ps overflows from the side wall of the plating tank 10 and flows into the overflow tank 20, and then returns to the plating tank 10 from the overflow tank 20 through the circulation pipeline 58a. A circulation pump 58b, a constant temperature unit 58c and a filter 58d are installed in the circulation pipeline 58a. The plating module 400 also includes: an adjustment plate (regulation plate) 14 having an opening 14a for adjusting the potential distribution on the substrate Wf; and a stirring rod 15 for stirring the plating liquid Ps so that sufficient metal ions are uniformly supplied to the surface of the substrate Wf during the plating of the substrate Wf. In addition, the above structure is an example, and the structure of the plating module 400, etc. can adopt other structures.

[0128] In the vertical plating module, the substrate Wf held in the substrate holder 30 is carried into the plating module 400 after being processed in the pre-wet module 200 and the pre-preg module 300. Figure 18 As shown, the substrate holder 30 includes a front plate 210 and a rear plate 220, and the substrate Wf is sandwiched and held by the front plate 210 and the rear plate 220. A sealed space (inner space) 33 is formed between the front plate 210 and the rear plate 220 of the substrate holder 30, which is enclosed by inner seals 215 and 225 and an outer seal 216.

[0129] like Figure 18 As shown in FIG. 2 , the rear plate 220 is provided with an introduction passage 231 and an exhaust passage 232 for communicating the internal space 33 of the substrate holder 30 with the outside of the substrate holder 30 . Figure 18 2 , the introduction passage 231 and the exhaust passage 232 are shown as one structure for convenience, but they are independent structures. The introduction passage 231 and the exhaust passage 232 are respectively provided with valves 231A and 232A for controlling the conduction and disconnection of each passage. The valves 231A and 232A are controlled by the control module 800. The introduction of liquid into the internal space 33 of the substrate holder 30 can be carried out, for example, by immersing the substrate holder 30 holding the substrate Wf in the liquid (processing liquid, such as pure water) in the processing tank of the pre-wetting module 200 during the pre-wetting process before the plating process, opening the valve 231A of the introduction passage 231, and introducing pure water into the internal space 33 of the substrate holder 30 via the introduction passage 231, thereby filling the internal space 33 with pure water. Alternatively, the substrate holder 30 holding the substrate Wf may be immersed in the liquid within the processing tank, and the valves 231A and 232A may be opened to introduce pure water into the internal space 33 while simultaneously exhausting air and pure water from the internal space 33, thereby filling the internal space 33 with pure water. The internal space 33 is preferably completely filled with pure water to eliminate any residual air, but depending on the desired effect (described later), some residual air or bubbles may be permitted. While an example of introducing pure water into the internal space of the substrate holder in the pre-wetting module has been described, pure water may also be introduced into the internal space of the substrate holder in another module, or another module for introducing a liquid such as pure water into the internal space of the substrate holder may be provided.

[0130] (External power supply type, insoluble protective electrode)

[0131] Figure 18 The structure of the vertical plating module 400 is shown in which the insoluble protective electrode 235A is biased toward the high potential side relative to the joint 50 (seed layer Sd) in the internal space 33 of the substrate holder 30. As described above, the internal space 33 is filled with a liquid (e.g., pure water) such as a processing liquid of the pre-wetting module 200. This structure is equivalent to Figure 7 and Figure 8 The example of using the insoluble protective electrode 238A in the embodiment is applied to the structure of the vertical plating module. According to this structure, Figure 7 and Figure 8 As described above, by making the protective electrode 238A function as an anode and the seed layer Sd function as a cathode, the oxidation reaction of Cu in the seed layer Sd can be suppressed, and the corrosion of the seed layer Sd can be suppressed or prevented. Therefore, the corrosion of the seed layer Sd can be suppressed or prevented, and the reduction in the uniformity of the plating film thickness can be suppressed or prevented.

[0132] (External power supply type, soluble protective electrode)

[0133] exist Figure 18 In the embodiment shown, Figure 7 and Figure 8 Similarly, as the material of the protective electrode 235A, a material having a natural potential (standard electrode potential) that is the same as that of the material of the seed layer Sd, or a material having a natural potential (standard electrode potential) lower than that of the material of the seed layer Sd can also be used. In this case, the protective electrode 235A is biased toward the high potential side relative to the seed layer Sd by the DC power supply 236A, thereby dissolving the protective electrode 235A before the seed layer Sd, so that the protective electrode 235A functions as a sacrificial electrode (soluble electrode). The material of the protective electrode 235A can be, for example, the same material as the seed layer Sd (the same material as the plated metal). According to this configuration, compared with the reference Figure 7 and Figure 8 As described above, the soluble guard electrode 235A dissolves prior to the seed layer Sd, thereby suppressing or preventing corrosion of the seed layer Sd. Therefore, corrosion of the seed layer Sd can be suppressed or prevented, and degradation of the uniformity of the plating film thickness can be suppressed or prevented.

[0134] exist Figure 18 In the embodiment shown, Figure 7 and Figure 8 As described in the embodiment of the present invention, the current detector 237A can monitor the current flowing between the protective electrode 235A and the connector 50 (busbar 49) through the liquid 60 or the resistance therebetween to detect leakage of the plating liquid Ps into the internal space 33. Figure 18 In the example, the protection electrode 235A may not be used for leakage detection, but the protection electrode 235A may be used only as an electrode for preventing the seed layer Sd from corroding. Figure 18In the present invention, a DC voltage based on a DC power supply (DC power supply) 236A is applied between the protective electrode 235A and the connector 50 (busbar 49), and the DC current is detected by a current detector 237A. However, an AC power supply (AC power supply) can also be used instead of the DC power supply 236A, and the AC current or impedance between the protective electrode 235A and the connector 50 (busbar 49) is monitored by the current detector to detect leakage.

[0135] (Direct connection type, soluble guard electrode)

[0136] Figure 19 Indicates a structure in which a soluble protective electrode 235B is connected to the connector 50 in the internal space of the substrate holder of the vertical plating module, that is, the protective electrode 235B is fixed to the connector 50 and electrically connected to the seed layer Sd via the connector 50. In addition, the protective electrode 235B can also be electrically connected to the seed layer Sd via a conductor other than the connector 50, or it can be electrically connected to the connector 50 via a conductor other than the connector 50. In addition, a structure in which the protective electrode 235B directly contacts and is electrically connected to the seed layer Sd when the substrate Wf is held by the substrate holder 30 can also be adopted. This structure is equivalent to Figure 9 and Figure 10 The embodiment of the present invention is applied to the structure of the vertical plating module. According to this structure, Figure 9 and Figure 10 As described above, the soluble guard electrode 235B dissolves before the seed layer Sd, thereby suppressing or preventing corrosion of the seed layer Sd. Therefore, corrosion of the seed layer Sd can be suppressed or prevented, and degradation of the uniformity of the plating film thickness can be suppressed or prevented.

[0137] In addition, Figure 18 and Figure 19 , the structure of a substrate holder 30 for single-sided plating in which both sides of the substrate Wf are exposed to the plating liquid is shown, but it is not limited to a substrate holder for single-sided plating. It can also be a substrate holder for double-sided plating, or a substrate holder for single-sided plating in which only one side of the substrate Wf is exposed.

[0138] According to the above embodiment, since the internal space 33 of the substrate holder 30 is filled with liquid (e.g., pure water), the pressure difference between the inside and outside of the internal space 33 is reduced compared to a case where the internal space 33 is hollow, and leakage of the plating solution into the internal space 33 can be suppressed or prevented. As a result, a decrease in the uniformity of the plating film thickness due to leakage of the plating solution can be suppressed or prevented.

[0139] According to the above embodiment, even if leakage of the plating solution occurs, since the internal space 33 is filled with liquid (e.g., pure water), the intrusion of the plating solution into the internal space 33 is limited to the amount of diffusion and is suppressed to a very small amount, thereby suppressing the dissolution (corrosion) of the seed layer Sd caused by the local battery effect and / or shunt current caused by the dissolved oxygen concentration. In addition, since the plating solution that invades the internal space 33 is diluted by the liquid (e.g., pure water), the corrosion of the seed layer Sd can be further suppressed. Thus, the reduction in the uniformity of the plating film thickness can be suppressed or prevented.

[0140] Furthermore, according to the above embodiment, since the internal space 33 is filled with liquid (e.g., pure water) and has a low oxygen concentration, the dissolution of the seed layer Sd due to local cell action caused by dissolved oxygen can be suppressed. This can suppress or prevent a decrease in the uniformity of the plating film thickness.

[0141] Furthermore, according to the above embodiment, even if a potentially corrosive amount of plating solution leaks, the protective electrodes 235A and 235B can suppress or prevent dissolution of the seed layer Sd. This can suppress or prevent a decrease in the uniformity of the plating film thickness due to plating solution leakage.

[0142] [Other embodiments]

[0143] (1) In the above embodiment, a resist pattern is cited as an example of a pattern on a substrate, but the pattern can be a pattern of a via hole or groove for forming wiring, or a pattern of a resist or insulating film for forming a bump, rewiring, or electrode pad, or any pattern that defines the shape of other plating films.

[0144] (2) The liquid introduced into the interior space of the substrate holder may be a liquid other than water, as long as it does not corrode the structural components exposed to the interior space of the substrate holder. For example, a liquid that does not contain metal salts (a liquid having a metal salt concentration less than a specified concentration (e.g., 5 g / L)) can be used. Examples of such liquids include tap water, natural water, and pure water. Examples of pure water include deionized water (DIW), distilled water, purified water, or RO water.

[0145] (3) The structure of the substrate holder is not limited to the above-mentioned example. The above-mentioned embodiment can be applied to a substrate holder of any structure as long as the substrate holder has an internal space in which the joint is sealed.

[0146] At least the following aspects can be grasped from the above-described embodiment.

[0147] [1] According to one embodiment, a substrate holder is provided, which is used to hold a substrate and bring the substrate into contact with a plating liquid for plating, and comprises: a connector for contacting a seed layer formed on the surface of the substrate and supplying power; a protective electrode biased toward a high potential side relative to the connector, or comprising a material having a natural potential lower than that of the seed layer, and the connector being electrically connected to the seed layer directly or via a conductor; and a holder body having an internal space, which, when the substrate is held by the substrate holder, accommodates the outer periphery of the substrate, the connector and the protective electrode in a sealed state from the outside of the substrate holder, and holds liquid covering at least a portion of the protective electrode and the contact portion between the seed layer and the connector.

[0148] "Liquid that covers at least a portion of the protective electrode and the contact area between the seed layer and the connector" includes: the entire protective electrode is covered by the liquid; the entire seed layer arranged in the internal space is covered by the liquid; the entire connector is covered by the liquid; and / or the entire internal space is covered by the liquid.

[0149] According to this method, the liquid near the protective electrode or the material of the protective electrode is oxidized in preference to the material of the seed layer, which can suppress the material of the seed layer from dissolving in the liquid, and thus can suppress or prevent the corrosion (deterioration) of the seed layer. The effect of the local battery on the surface of the seed layer caused by the dissolved oxygen concentration gradient in the liquid covering the joint etc. can be suppressed, thereby suppressing or preventing the corrosion of the seed layer. In addition, even when the plating solution invades the internal space of the substrate holder, the corrosion of the seed layer caused by the local battery effect and / or the shunt current can be suppressed or prevented. Since the degradation of the seed layer can be suppressed by the protective electrode, the uniformity of the coating thickness can be suppressed or prevented from being reduced.

[0150] [2] According to one embodiment, the guard electrode is an insoluble electrode and is biased toward a higher potential with respect to the connector.

[0151] This method eliminates the need for regular guard electrode replacement or reduces its frequency, making guard electrode maintenance easier. Furthermore, it reduces the likelihood of electrode material (metal) dissolved from the guard electrode being carried into the plating solution and contaminating it. Furthermore, it reduces the likelihood of oxides from the electrode material dissolved from the guard electrode precipitating on joints and seals and contaminating them.

[0152] [3] According to one embodiment, a voltage that is sufficiently larger than the difference between the natural potentials of the protective electrode and the seed layer is applied between the protective electrode and the seed layer.

[0153] According to this aspect, the protective electrode and the seed layer can be made to reliably function as the anode and the cathode, respectively, and dissolution of the seed layer can be reliably suppressed or prevented.

[0154] [4] According to one embodiment, the protective electrode is fixed to the joint via a separator.

[0155] According to this aspect, the guard electrode can be easily and appropriately provided in a narrow sealed space in the substrate holder.

[0156] [5] According to one embodiment, the protective electrode has a lower natural potential than the seed layer, is electrically connected to the seed layer directly or via a conductor, and functions as a soluble sacrificial electrode.

[0157] According to this aspect, an external power supply for biasing the guard electrode is unnecessary, and the structure of the substrate holder and / or the plating module can be simplified.

[0158] [6] According to one embodiment, the protective electrode is fixed to the connector and is electrically connected to the seed layer via the connector.

[0159] According to this aspect, the guard electrode is directly fixed to the tab, thereby electrically connecting the guard electrode to the seed layer via the tab. Therefore, the structure for connecting the guard electrode can be simplified.

[0160] [7] According to one embodiment, the protective electrode is a soluble electrode and is biased toward a higher potential with respect to the connector.

[0161] In this method, if the same material as the seed layer is used as the material of the protective electrode, the protective electrode can function as a sacrificial electrode for the seed layer. In this case, even if the metal dissolved from the protective electrode is brought into the plating solution, the possibility of contaminating the plating solution can be reduced.

[0162] [8] According to one embodiment, the protective electrode is fixed to the joint via a separator.

[0163] According to this aspect, the guard electrode can be easily and appropriately provided in a restricted narrow sealed space in the substrate holder.

[0164] [9] According to one embodiment, the protective electrode is provided continuously or discontinuously at a location surrounding the periphery of the substrate when the substrate holder holds the substrate.

[0165] According to this aspect, the protection electrode can be arranged around the entire periphery (edge portion) of the substrate where corrosion is highly likely, thereby effectively suppressing corrosion of the seed layer.

[0166]

[10] According to one embodiment, the protective electrode is arranged in a circumferential shape so that when the substrate holder holds the substrate, the distance from the edge of the substrate becomes less than a predetermined distance.

[0167] According to this aspect, since the protection electrode is arranged near the edge of the substrate, the seed layer in the outer peripheral portion (edge portion) of the substrate, which is likely to be corroded, can be effectively protected from corrosion.

[0168]

[11] According to one embodiment, the liquid has an electrical conductivity of 1000 μS / cm or less.

[0169] This method allows the conductivity of the liquid covering the joint, etc., to reach 1000 μS / cm. In the wet contact method for plating a substrate while the joint of the substrate holder is covered with liquid, it is known that without a guard electrode, the liquid conductivity must be maintained below 50 μS / cm. On the other hand, using a guard electrode significantly reduces the need to manage the conductivity of the liquid covering the joint, etc., because it can suppress corrosion of the seed layer.

[0170]

[12] According to one embodiment, the liquid is pure water, or pure water that has been degassed or replaced with an inert gas.

[0171] According to this embodiment, pure water such as DIW, which is generally used in plating equipment, can be used as the liquid for covering the joint and the like, and there is no need to separately prepare a liquid for covering the joint and the like.

[0172]

[13] According to one embodiment, the guard electrode functions as a detector configured to detect leakage of the plating solution into the internal space by monitoring a current flowing between the connector or a wiring electrically connected to the connector and the electrode when the liquid is introduced into the internal space. The "wiring electrically connected to the connector" is, for example, a busbar.

[0173] According to this aspect, the presence or absence of leakage of the plating solution can be detected by monitoring the current flowing between the guard electrode and the joint, etc., and therefore, there is no need to separately provide an electrode for leakage detection.

[0174]

[14] According to one embodiment, the substrate holder is used for a horizontal plating module that holds the substrate in a horizontal position, or for a vertical plating module that holds the substrate in a vertical position.

[0175] According to this embodiment, the above-mentioned structure is applied to the substrate holder for the horizontal and vertical plating modules, and the above-mentioned effects can be achieved.

[0176]

[15] According to one embodiment, a plating apparatus is provided, comprising: a substrate holder according to any one of embodiments 1 to 14; a liquid supply module for supplying liquid to the internal space of the substrate holder; and a plating module for contacting the substrate held in the substrate holder with the plating liquid to plate the substrate. The liquid supply module can be composed of a cleaning nozzle, a processing module using liquid (e.g., a pre-wetting module), and the like.

[0177] According to this aspect, the liquid can be automatically supplied to the internal space of the substrate holder by the liquid supply module in the plating apparatus.

[0178]

[16] According to one embodiment, the liquid supply module includes a cleaning nozzle that cleans the internal space of the substrate holder and replaces the liquid in the internal space.

[0179] According to this embodiment, before plating each substrate, the inner space of the substrate holder is cleaned to retain liquid, thereby allowing the joints and the like in the inner space of the substrate holder to be constantly coated with clean liquid for substrate plating.

[0180]

[17] According to one embodiment, a pre-wetting module for pre-wetting the substrate is further provided, and the plating module holds the wetted substrate on the substrate holder.

[0181] According to this aspect, the substrate after the pre-wetting process can be carried into the plating module while being kept wet and held on the substrate holder, and a drying step of the substrate edge is unnecessary.

[0182]

[18] According to one embodiment, a method for plating a substrate is provided, comprising: preparing a substrate holder having a protective electrode, the protective electrode being biased toward a high potential side relative to a connector for contacting a seed layer formed on the surface of the substrate and supplying power, or having a material having a natural potential lower than that of the seed layer of the substrate and being electrically connected to the seed layer directly or via a conductor; introducing a liquid into the internal space of the substrate holder that accommodates the outer periphery of the substrate in a sealed state from the outside, and covering at least a portion of the protective electrode and a contact portion of the connector of the substrate holder with the seed layer of the substrate with the liquid in the internal space; and plating the substrate held in the substrate holder while the liquid is introduced into the internal space of the substrate holder.

[0183] The embodiments of the present invention have been described above, but the embodiments of the invention described above are for ease of understanding of the present invention and do not limit the present invention. The present invention can of course be changed and improved without departing from its main purpose, and its equivalents are also included in the present invention. In addition, within the scope of at least a part of the above-mentioned problems, or within the scope of at least a part of the effect, any combination of the embodiments and modifications can be performed, and any combination or omission of the various constituent elements recorded in the claims and the specification can be performed.

[0184] The entire disclosure of U.S. Patent No. 7,727,366 (Patent Document 1), U.S. Patent No. 8,168,057 (Patent Document 2), Japanese Patent Publication No. 2020-117763 (Patent Document 3), and Japanese Patent Publication No. 2020-117765 (Patent Document 4), including the specification, claims, drawings, and abstract, are incorporated into this application by reference in their entirety.

[0185] The entire disclosure of International Patent Application No. 2021 / 038404 and International Patent Application No. 2021 / 000460 including the specification, claims, drawings and abstract is incorporated into this application by reference in its entirety.

Claims

1. A substrate holder for holding a substrate and allowing the substrate to contact a plating solution for plating, wherein: have: a connector, configured to contact the seed layer formed on the surface of the substrate and supply power; The guard electrode is an insoluble electrode and is biased toward a high potential side relative to the joint; as well as The holder body has an internal space, which, when the substrate is held by the substrate holder, accommodates the outer periphery of the substrate, the connector and the protective electrode in a sealed state from the outside of the substrate holder, and retains the liquid covering at least a portion of the protective electrode and the contact area between the seed layer and the connector.

2. The substrate holder according to claim 1, wherein A voltage greater than a difference between the natural potentials of the guard electrode and the seed layer is applied between the guard electrode and the seed layer.

3. The substrate holder according to claim 1, wherein The guard electrode is fixed to the joint via a separator.

4. The substrate holder according to any one of claims 1 to 3, wherein The protective electrode is provided continuously or discontinuously at a location surrounding the outer periphery of the substrate when the substrate holder holds the substrate.

5. The substrate holder according to any one of claims 1 to 3, wherein The protective electrode is arranged in a circumferential shape so that a distance from an edge of the substrate becomes equal to or less than a predetermined distance when the substrate holder holds the substrate.

6. The substrate holder according to any one of claims 1 to 3, wherein The liquid has an electrical conductivity of 1000 μS / cm or less.

7. The substrate holder according to any one of claims 1 to 3, wherein The liquid is pure water, or pure water that has been degassed or replaced with an inert gas.

8. The substrate holder according to any one of claims 1 to 3, wherein The guard electrode functions as a detector. The detector is configured to detect leakage of the plating solution into the internal space by monitoring a current flowing between the joint or a wiring electrically connected to the joint and the electrode when the liquid is introduced into the internal space.

9. The substrate holder according to any one of claims 1 to 3, wherein The substrate holder is a substrate holder for a horizontal plating module that holds the substrate in a horizontal orientation, or a substrate holder for a vertical plating module that holds the substrate in a vertical orientation.

10. A plating device, wherein: have: The substrate holder according to any one of claims 1 to 9; a liquid supply module that supplies liquid to the inner space of the substrate holder; and The plating module plates the substrate by bringing the substrate held by the substrate holder into contact with a plating liquid.

11. The plating device according to claim 10, wherein The liquid supply module includes a cleaning nozzle that cleans the internal space of the substrate holder and replaces the liquid in the internal space.

12. The plating device according to claim 10, wherein The plating device further comprises a pre-wetting module for performing a pre-wetting process on the substrate. The plating module holds the wet substrate on the substrate holder.

13. A method for plating a substrate, wherein: include: preparing a substrate holder having a protective electrode, the protective electrode being an insoluble electrode and biased toward a higher potential with respect to a contact for contacting a seed layer formed on a surface of the substrate and supplying power; introducing a liquid into an internal space of the substrate holder that accommodates the outer periphery of the substrate in a sealed state from the outside, and covering at least a portion of the guard electrode and a contact portion between the joint of the substrate holder and the seed layer of the substrate in the internal space with the liquid; as well as The substrate held by the substrate holder is plated in a state where liquid is introduced into the internal space of the substrate holder.

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