TW202407166A - Substrate holder, apparatus for plating, and method of plating - Google Patents

Abstract

There is provided a substrate holder configured to hold a substrate such that the substrate is exposed to and is brought into contact with a plating solution to be plated. The substrate holder comprises a contact that comes into contact with a seed layer formed on a surface of the substrate to feed electricity; a protective electrode that is biased to a higher potential side relative to the contact or that comprises a material having a lower spontaneous potential than a spontaneous potential of the seed layer and that is electrically connected with the seed layer directly or via an electrical conductor; and a holder main body provided with an internal space being configured to place therein an outer circumferential portion of the substrate, the contact and the protective electrode such as to be sealed from outside of the substrate holder in a state that the substrate is held by the substrate holder and configured to store therein a liquid that covers at least part of the protective electrode and at least a contact location between the seed layer and the contact.

Description

Substrate holder, plating device, and plating method

The present invention relates to a substrate holder, a plating device, and a plating method.

In electroplating, if the plating liquid leaks into the substrate holder due to some undesirable conditions (eg, irregularities in the substrate, deterioration of seals, etc.), the seed layer will corrode due to the plating liquid intruding into the holder. and/or dissolution, resulting in poor conduction, resulting in reduced plating uniformity.

U.S. Patent No. 7727366 (Patent Document 1) and U.S. Patent No. 8168057 (Patent Document 2) describe pressurizing one side of the seal of the substrate with a fluid to prevent the fluid from intruding from the opposite side of the seal. . Japanese Patent Application Laid-Open No. 2020-117763 (Patent Document 3) and Japanese Patent Application Laid-Open No. 2020-117765 (Patent Document 4) describe injecting liquid into an internal space that seals and accommodates the outer peripheral portion of a substrate to prevent plating liquid By intruding into the internal space, the plating liquid is prevented from being deposited on the outer peripheral portion of the substrate and the contact parts.

Patent Document 1: U.S. Patent No. 7727366 Specification Patent Document 2: U.S. Patent No. 8168057 Specification Patent Document 3: Japanese Patent Application Publication No. 2020-117763 Patent Document 4: Japanese Patent Application Publication No. 2020-117765

Even if countermeasures such as the technology described in the above-mentioned patent document are taken, there is a possibility that the plating liquid will invade the internal space depending on the unevenness of the substrate and the degree of deterioration of the seal. However, the above-mentioned patent document does not describe any countermeasures for plating. Effective countermeasures against liquid intrusion into the internal space. In addition, in the wet contact method in which the contact of the substrate holder and the seed layer of the substrate are partially covered with a liquid (pure water, etc.) to plate the substrate, even if the plating liquid does not invade the internal space , the seed layer may also corrode due to local cell action caused by dissolved oxygen concentration gradients in the liquid.

One object of the present invention is to provide a technology for suppressing deterioration of a seed layer of a substrate. Furthermore, one of the objects of the present invention is to suppress a decrease in the uniformity of the thickness of the plating film even when the plating liquid invades the sealed space of the substrate holder. In addition, one of the objects of the present invention is to detect in advance that the plating liquid has invaded the sealed space of the substrate holder.

According to one aspect of the present invention, there is provided a substrate holder for holding a substrate and bringing the substrate into contact with a plating liquid to perform plating, and having a contact for contacting a seed formed on the surface of the substrate. layer contacts and supplies power; the protective electrode has a material that is biased toward the high potential side relative to the above-mentioned contact point, or has a lower natural potential than the above-mentioned seed layer, and the protective electrode is electrically connected to the above-mentioned seed layer directly or via a conductor. connection; and a holder main body having an internal space that seals the outer peripheral portion of the substrate, the contact point, and the above-mentioned substrate from the outside of the substrate holder while the substrate is held by the substrate holder. The protective electrode accommodates and holds the liquid covering at least a part of the protective electrode and a contact portion between the seed layer and the contact.

Hereinafter, the plating apparatus 1000 and the plating method according to the embodiment of the present invention will be described with reference to the drawings. In addition, the drawings are schematically illustrated in order to make it easy to understand the characteristics of the article, and the dimensional ratio of each component is not necessarily the same as the actual one. In addition, in several figures, the orthogonal coordinates of X-Y-Z are illustrated for reference. In this orthogonal coordinate, the Z direction corresponds to the upward direction, and the -Z direction corresponds to the downward direction (the direction of gravity).

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, mirrors, optical components, micromechanical components, or partially manufactured integrated circuits. , any other object to be processed. The substrate includes any shape including a polygon and a circle. In addition, in this manual, "front surface", "rear surface", "upper surface", "lower surface", "front", "rear", "upper", "lower", "left", However, for convenience of explanation, the position and direction on the paper of the drawings showing the illustrations may be different in the actual layout such as when the device is used.

(first embodiment) FIG. 1 is a perspective view showing the overall structure of a plating apparatus 1000 according to this embodiment. FIG. 2 is a plan view showing the overall structure of the plating apparatus 1000 according to this embodiment. As shown in FIGS. 1 and 2 , the plating device 1000 includes a load port 100 , a transfer robot 110 , an aligner 120 , a prewet module 200 , a prepreg module 300 , and a plating device 1000 . Module 400, cleaning module 500, rotary rinsing and drying module 600, conveying device 700 and control module 800.

The load port 100 is a module for loading wafers (substrates) stored in a cassette such as a FOUP (not shown) into the plating apparatus 1000 or for unloading substrates from the plating apparatus 1000 to the cassette. In this embodiment, four loading ports 100 are arranged in a horizontal direction, but the number and arrangement of the loading ports 100 are arbitrary. The transport robot 110 is a robot for transporting substrates, and is configured to transfer substrates between the loading port 100 , the aligner 120 , and the transport device 700 . The transfer robot 110 and the transfer device 700 can transfer the substrates via a temporary placement table (not shown) when transferring substrates between the transfer robot 110 and the transfer device 700 .

The aligner 120 is a module for aligning the position of the orientation plane, notches, etc. of the substrate with a predetermined direction. In this embodiment, two aligners 120 are arranged horizontally, but the number and arrangement of the aligners 120 are arbitrary. The prewet module 200 makes the treatment liquid such as pure water or degassed water wet the plated surface of the substrate before the plating process, thereby replacing the air inside the pattern formed on the surface of the substrate with the treatment liquid. The prewet module 200 is configured to perform a prewet process in which the treatment liquid inside the pattern is replaced with the plating liquid during plating, thereby easily supplying the plating liquid to the inside of the pattern. In this embodiment, two pre-moistening modules 200 are arranged vertically, but the number and arrangement of the pre-moistening modules 200 are arbitrary.

For example, the prepreg module 300 is configured to remove an oxide film with high resistance existing on the surface of a seed layer formed on the plated surface of the substrate before plating using a treatment solution such as sulfuric acid or hydrochloric acid to remove the plated base surface. Pre-soak for cleaning or activation. In this embodiment, two prepreg modules 300 are arranged vertically, but the number and arrangement of the prepreg modules 300 are arbitrary. The plating module 400 performs a plating process on the substrate. In this embodiment, the components of the 12 plating modules 400 arranged with three units arranged in the up-down direction and four units arranged in the horizontal direction are two groups, and a total of 24 plating modules 400 are provided. However, the plating modules 400 are arranged in two groups. The number and configuration of groups 400 is arbitrary.

The cleaning module 500 is configured to perform a cleaning process on the substrate in order to remove the plating liquid and the like remaining on the substrate after the plating process. In this embodiment, two cleaning modules 500 are arranged vertically, but the number and arrangement of the cleaning modules 500 are arbitrary. The spin rinse and dry module 600 is a module for drying the cleaned substrate by rotating it at high speed. In this embodiment, two rotary rinsing and drying modules 600 are arranged vertically, but the number and arrangement of the rotary rinsing and drying modules 600 are arbitrary. The transport device 700 is a device for transporting substrates between a plurality of modules in the plating device 1000 . The control module 800 is configured as a plurality of modules for controlling the plating apparatus 1000, and can be configured as a general computer or a special-purpose computer equipped with an input/output interface for input and output with an operator, for example.

An example of a series of plating processes performed by the plating apparatus 1000 will be described. First, the substrate stored in the cassette is loaded into the loading port 100 . Next, the transport robot 110 takes out the substrate from the cassette in the loading port 100 and transports the substrate to the aligner 120 . The aligner 120 aligns the position of the orientation plane, notches, etc. of the substrate with a predetermined direction. The transfer robot 110 delivers the substrate whose direction has been aligned by the aligner 120 to the transfer device 700 .

The conveying device 700 conveys the substrate received from the conveying robot arm 110 to the premoistening module 200 . The pre-wetting module 200 performs pre-wetting treatment on the substrate. The conveying device 700 conveys the pre-wetted substrate to the prepreg module 300 . The prepreg module 300 performs prepreg processing on the substrate. The conveying device 700 conveys the prepreg-processed substrate to the plating module 400 . The plating module 400 performs a plating process on the substrate.

The transport device 700 transports the plated substrate to the cleaning module 500 . The cleaning module 500 performs cleaning processing on the substrate. The conveying device 700 conveys the cleaned substrate to the rotary rinsing and drying module 600 . The rotating rinse and dry module 600 performs a drying process on the substrate. The conveying device 700 delivers the dried substrate to the conveying robot 110 . The transport robot 110 transports the substrate received from the transport device 700 to the cassette of the loading port 100 . Finally, the cassette containing the substrate is unloaded from the loading port 100 .

In addition, the structure of the plating apparatus 1000 demonstrated in FIG. 1 and FIG. 2 is just an example, and the structure of the plating apparatus 1000 is not limited to the structure of FIG. 1, FIG. 2.

(Structure of plating module) 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 this embodiment have the same structure, one plating module 400 will be described.

FIG. 3 is a schematic diagram for explaining the structure of the plating module 400 of the plating apparatus 1000 according to this embodiment. The plating apparatus 1000 and the plating module 400 according to this embodiment are of a type called a face-down type, a cup type, or a horizontal type. The plating module 400 of the plating apparatus 1000 according to this embodiment mainly includes the plating tank 10 , a substrate holder 30 also called a plating head, a rotation mechanism 40 , a tilt mechanism 45 , and a lifting mechanism 46 . However, the tilt mechanism 45 may be omitted.

The plating tank 10 according to this embodiment is composed of a bottomed container having an opening at the upper side. The plating tank 10 has a bottom wall and an outer peripheral wall extending upward from an outer peripheral edge of the bottom wall, and the upper portion of the outer peripheral wall is open. The plating liquid Ps is accumulated inside the plating tank 10 . In this embodiment, the plating tank 10 has a cylindrical shape.

The plating liquid Ps is not particularly limited as long as it is a solution containing ions of metal elements constituting the plating film. 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 liquid Ps. In addition, in this embodiment, the plating liquid Ps contains a predetermined additive. However, it is not limited to this structure, and the plating liquid Ps may also be a structure which does not contain an additive.

An anode 16 is arranged inside the plating tank 10 . The specific type of anode 16 is not particularly limited, and 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, etc. can be used.

An overflow tank 20 composed of a bottomed container is provided outside the plating tank 10 . The overflow tank 20 temporarily stores the plating liquid Ps exceeding the upper end of the plating tank 10 . In one example, the plating liquid Ps in the overflow tank 20 is discharged from a discharge port (not shown) for the overflow tank 20 , is temporarily stored in a storage tank (not shown), and then returns to the plating tank 10 again.

A porous resistor 17 is disposed above the anode 16 inside the plating tank 10 . Specifically, the resistor 17 is composed of a porous plate member having a plurality of pores (pores). The plating liquid Ps on the lower side than the resistive body 17 can flow to the upper side than the resistive body 17 through the resistive body 17 . This resistor 17 is a component provided to uniformize the electric field formed between the anode 16 and the substrate Wf. By arranging such a resistor 17 in the plating tank 10 , the thickness of the plating film (plated layer) formed on the substrate Wf can be easily made uniform. In addition, the resistor 17 is not an essential structure in this embodiment, and this embodiment can also be a structure without the resistor 17 .

The substrate holder 30 is a member that holds the substrate Wf serving as the cathode. Specifically, the substrate holder 30 is disposed above the anode 16 (and above the resistor 17 in this embodiment). The substrate holder 30 holds the substrate Wf so that the lower surface Wfa of the substrate Wf faces the anode 16 and the resistor 17 . In addition, the lower surface Wfa of the substrate Wf corresponds to the surface to be plated.

The substrate holder 30 according to this embodiment includes a first holding member 31 , a second holding member 32 , a contact 50 , and a sealing member 55 . The first holding member 31 and the second holding member 32 may be collectively referred to as a holder body. The substrate holder 30 holds the substrate Wf so that the substrate Wf is sandwiched between the first holding member 31 and the second holding member 32 . The first holding member 31 holds the upper surface of the substrate Wf. The second holding member 32 holds the outer peripheral portion of the lower surface Wfa of the substrate Wf and has an opening through which the plated surface of the substrate Wf is exposed. Specifically, the second holding member 32 according to this embodiment holds the outer peripheral portion of the lower surface Wfa of the substrate Wf via the sealing member 55 . When the substrate holder 30 holds the substrate Wf, the sealing member 55 is in close contact with the substrate Wf to protect the contacts 50 and the contact area of the substrate Wf (the area of the outer peripheral portion of the substrate in contact with the contacts 50 ) from plating. The sealing space (inner space) affected by the covering liquid 33.

The substrate holder 30 is connected to the rotation shaft 41 of the rotation mechanism 40 . The rotation mechanism 40 is a mechanism for rotating the substrate holder 30 . As the rotation mechanism 40, a known mechanism such as a motor can be used. The tilt mechanism 45 is a mechanism for tilting the rotation mechanism 40 and the substrate holder 30 . As the tilt mechanism 45, a known tilt mechanism such as a piston cylinder can be used. The lifting mechanism 46 is supported by a support shaft 47 extending in the up-and-down 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 linear actuator can be used.

The contact point 50 of the substrate holder 30 is connected to the negative electrode of the DC power supply 90 via wiring (bus bar, etc.) in the substrate holder 30 , and the anode 16 is connected to the positive electrode of the DC power supply 90 via the wiring. The DC power supply 90 causes a DC current or pulse current to flow between the substrate Wf and the anode 16 via the plating liquid Ps as a plating current. The DC power supply 90 is a power supply driven by a constant current.

When the plating process is performed, the rotation mechanism 40 rotates the substrate holder 30 and the lifting mechanism 46 moves the substrate holder 30 downward to immerse the substrate Wf in the plating liquid Ps of the plating tank 10 . In addition, in this manner, when the substrate Wf is immersed in the plating liquid Ps, the tilt mechanism 45 may tilt the substrate holder 30 as necessary. Next, the DC power supply 90 causes electricity to flow between the anode 16 and the substrate Wf via the plating liquid Ps. Thereby, a plating film is formed on the lower surface Wfa of the substrate Wf.

The action of the plating module 400 is controlled by the control module 800 . The control module 800 includes a microcomputer including a CPU (Central Processing Unit: central processing unit) 801 as a processor, a storage unit 802 as a non-transitory storage medium, and the like. The control module 800 controls the controlled part of the plating module 400 by causing the CPU 801 to operate based on the instructions of the program stored in the storage unit 802 . Programs include, for example, programs that execute conveyance control of conveyor arms and conveyor devices, control of processes in each processing module, control of plating processes in plating modules, control of cleaning processes, and programs that detect abnormalities in various equipment. . Storage media can include non-volatile and/or volatile storage media. As the storage medium, well-known storage media such as computer-readable memories such as ROM, RAM, and flash memory, or disk-shaped storage media such as hard disks, CD-ROMs, DVD-ROMs, and floppy disks can be used. The control module 800 is configured to communicate with a higher-level controller (not shown) that collectively controls the plating device and other related devices, and to exchange data with a database included in the higher-level controller. Part or all of the functions of the control module 800 can also be composed of hardware such as ASIC. Part or all of the functions of the control module 800 may also be composed of a PLC, a sequencer, etc. Part or all of the control module 800 can be disposed inside and/or outside the casing of the plating device. Part or all of the control module 800 is communicably connected to each part of the plating device through wired and/or wireless means.

(Substrate holder) FIG. 4 is a schematic enlarged cross-sectional view showing a part of the substrate holder 30 (portion A1 in FIG. 3 ). Referring to FIGS. 3 and 4 , the substrate holder 30 according to this embodiment is provided with contacts 50 that come into contact with the contact area of the outer peripheral portion of the lower surface Wfa of the substrate Wf to supply power to the substrate Wf. Specifically, the contact 50 according to this embodiment is arranged on the second holding member 32 of the substrate holder 30 . A plurality of contacts 50 according to this embodiment are arranged in the circumferential direction of the substrate holder 30 (specifically, the circumferential direction of the second holding member 32 ). Each contact 50 includes a plurality (for example, four) of plate-shaped electrodes called fingers. The plurality of contacts 50 are evenly arranged in the circumferential direction of the substrate holder 30 . In addition, the number of the plurality of contacts 50 is not particularly limited. In the present embodiment, the number of contacts 50 is 12 as an example. The plurality of contacts 50 are electrically connected to the DC power supply 90 ( FIG. 3 ), and power supplied from the DC power supply 90 is supplied to the substrate Wf (more specifically, the seed layer Sd formed on the lower surface Wa of the substrate Wf).

As shown in FIGS. 3 and 4 , the plating module 400 according to this embodiment includes a sealing member 55 for suppressing contact between the plating liquid Ps in the plating tank 10 and the contacts 50 . The sealing member 55 has a lip portion 55A provided to protrude toward the substrate side, and the lip portion 55A is in contact with the lower surface Wfa of the substrate Wf. Specifically, the lip portion 55A of the sealing member 55 according to this embodiment is arranged inside the contact point 50 (radially inside the substrate holder 30 ), and is sandwiched when the substrate Wf is held by the substrate holder 30 . It is held 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 55A is provided near the radially inner end of the sealing member 55 . The sealing member 55 has, for example, a ring shape so as to follow the outer peripheral portion of the substrate Wf. The plating module 400 includes such a sealing member 55 , thereby effectively preventing the plating liquid Ps from contacting the contacts 50 when the substrate Wf is immersed in the plating liquid Ps.

As shown in FIG. 4 , the second holding member 32 of the substrate holder 30 includes 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 member 55 is provided in the substrate receiving portion 32B. The second holding member 32 is a member that holds the sealing member 55 and is therefore also called a seal ring holder (SRH). In addition, the second holding member 32 may have a structure in which a plurality of components are assembled. For example, the outer peripheral wall 32A and the substrate receiving portion 32B may be provided separately and coupled to each other. The lip 55A contacts the substrate Wf, and as shown in FIG. 3 , a sealed space (inner space) 33 is formed in the substrate holder 30 to shield/protect the contact between the contact 50 and the substrate Wf (seed layer Sd of the contact area described later). The parts are protected from the influence of plating solution Ps.

The present embodiment is characterized in that, as shown in FIG. 4 , the substrate Wf is plated while the contact portion (the end portion in this example) of the contact 50 that is in contact with the substrate Wf is covered with the liquid 60 . Overwrite processing. The liquid 60 can be pure water, degassed water, or other liquids (liquids used in processes such as prewetting, presoaking, and cleaning). Specifically, a cleaning nozzle 71 (see FIG. 6 ) that can pour pure water on the contact 50 without removing the contact 50 from the device after the plating process, and a liquid receiving tray 72 that receives the cleaning drainage liquid are provided. A conductivity meter 74 that measures the conductivity (conductivity) of the cleaning drain liquid is disposed in the liquid receiving tray 72 and/or the cleaning pipe 73 that discharges the cleaning drain liquid, and the cleaning degree of the contact 50 is measured based on the conductivity of the cleaning drain liquid. When the electrical conductivity is lower than a predetermined threshold value determined through experiments or the like, supply of the cleaning liquid from the cleaning nozzle 71 is stopped. This allows the contact portion between the contact 50 and the substrate Wf (seed layer Sd) to be covered with the liquid 60 whose conductivity is controlled to be less than a predetermined threshold value. The electrical conductivity of the liquid 60 corresponds to the electrical insulating properties such that electric current does not flow via the liquid 60 between the electrically conductive components within the interior space 33 . However, when a protective electrode described below is used, the electrical conductivity may be a level that allows an anti-corrosion current to flow between conductive members such as seed layers and contacts and the protective electrode. As shown in FIG. 4 , even when the substrate Wf is not placed on the seal ring holder, it is preferable that the ends of the contacts 50 are always covered with the liquid 60 . Accordingly, even if the metal from the seed layer Sd adheres to the contact end due to repeated use of the contact, the contact end can always be biased to the low potential side with respect to the protective electrode by the protective electrode described later. This can prevent the metal attached to the contact end from being oxidized and stabilize the contact resistance over a long period of time.

During the plating process, current flows between the contact 50 and the substrate Wf in a state where the contact portion between the contact 50 and the substrate Wf is covered with the liquid 60 (for example, pure water) whose conductivity is less than a predetermined threshold. In this embodiment, the liquid 60 for covering the contact portion of the contact 50 with the substrate Wf can be held in the substrate receiving portion 32B. In addition, in this embodiment, the sealing member 55 (lip 55A in the example of FIG. 4 ) functions to suppress or prevent 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 functions 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 portion/storage portion for holding the liquid 60 (however, the liquid 60 does not need to be in contact with the outer peripheral wall 32A). That is, the substrate holder 30 has a container part/storage part for holding the liquid 60 in the internal space 33 .

In the experiment conducted by the applicant, in the configuration of this embodiment, the supply of pure water from the cleaning nozzle 71 was 13 mL or more. During this period, the substrate holder 30 was rotated at least once to uniformly supply pure water to the contacts 50 . The liquid volume of 13 mL is the amount of pure water required to completely wet the contact portion of one finger of the contact 50 with the substrate Wf (seed layer Sd). The liquid volume is the amount of pure water required for 12 contacts (one week of the substrate Wf1 The value obtained by adding the amounts), in other words, is the amount of pure water required to completely wet the contact portions of all the contacts 50 of the substrate holder 30 that are in contact with the substrate Wf. According to experiments conducted by the applicant, it is known that when the conductivity of the liquid (coating liquid) 60 is 50 μS/cm or less, the seed layer Sd of the substrate Wf will not be damaged (see International Patent Application No. 2021/038404) . That is, it is characterized in that after the contact 50 is cleaned, there is no need to shake off the liquid (for example, pure water) adhering to the contact 50, and the cleaning liquid whose conductivity is controlled below a predetermined threshold value is directly used for the next substrate processing. The coating liquid (coating water) used for the contact and substrate contact parts. This eliminates the trouble of drying the contacts and prevents the plating process from being performed in a state where the contacts 50 and the substrate Wf are not completely wetted. In addition, in other experiments conducted by the applicant, it was found that even if the conductivity of the liquid 60 is increased in the range of 1000 μS/cm or less when a protective electrode for anti-corrosion of the seed layer described below is provided, there will be no damage to the substrate. The seed layer Sd of Wf causes damage. Therefore, by providing a protective electrode described below, it is possible to significantly relax the control of the electrical conductivity of the coating liquid. In addition, it was found that due to the influence of de-scum treatment before plating, etc., when a certain substrate whose seed layer surface is covered with a thick oxide film is used, even if the conductivity is 50 μS/cm or less, There are also cases where corrosion proceeds more severely than usual. This is considered to be because, when the contact 50 is brought into contact with the seed layer Sd, the contact is pressed with a force exceeding a certain level, and the oxide film on the surface of the seed layer and a part of the seed layer are shaved off to expose the metal surface, thereby reducing the size of the seed layer. Contact resistance, but when the surface of the seed layer is covered by a thick oxide film, the corrosion parts are only concentrated near the contacts exposed on the metal surface, and the corrosion proceeds more seriously than usual. Even in such a case, corrosion can be effectively suppressed by providing a protective electrode described below. When a guard electrode described below is used, the range of the electrical conductivity of the liquid 60 is greatly relaxed, and therefore management of the electrical conductivity of the liquid 60 using a conductivity meter or the like can be omitted.

In addition, in the present embodiment, the contact area of the substrate Wf (the area in contact with the contact 50 ) that is wetted in pre-processing such as pre-moistening treatment is not dried until plating is completed. Thereby, the following malfunctions can be suppressed or prevented. If the contact area of the substrate that was wetted during the pretreatment is dried, water will leak into the surrounding pattern openings, and air bubbles may remain in the pattern openings during plating, resulting in an abnormality in which this part is not plated. In addition, , the surface of the seed layer in the contact area of the incompletely dried substrate may be oxidized and cause poor conduction. In addition, if the contact area between the seed layer of the substrate and the contact is not completely wetted, the seed layer Sd may cause local battery effects due to dissolved oxygen and/or shunt current (between the contact 50 and the seed layer Sd of the substrate Wf). Except for the contact area, the liquid is dissolved between the contact 50 and the seed layer Sd through the shunt of the liquid flow, causing power supply deviation and reducing the in-plane uniformity of the coating thickness.

(Principle of Seed Layer Corrosion) FIG. 20 is an explanatory diagram illustrating the dissolution of the seed layer due to the local cell effect caused by dissolved oxygen. Consider the situation where the plating liquid is mixed into the liquid Q in the air-filled sealed space 33 (Fig. 3). At this time, as shown in this figure, oxygen _O2 in the air dissolves into the liquid Q, Cu in the seed layer Sd transfers electrons to _O2 , _O2 becomes OH ^- , and Cu becomes ^{Cu2 +} , causing dissolution into the liquid Q As a result of the local cell, the seed layer Sd dissolves. Through this reaction, Cu is eluted from the seed layer Sd, the seed layer Sd becomes thinner, the resistance of the seed layer Sd increases, and there is a possibility that power supply deviation occurs. 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 increases due to corrosion of the seed layer Sd due to local battery action, dissolution of the seed layer Sd due to a shunt current described later is likely to occur, and the dissolution of the seed layer Sd further proceeds.

FIG. 21 is an explanatory diagram illustrating the dissolution of the seed layer caused by the shunt current. FIG. 22 is an equivalent circuit diagram illustrating the shunt current. In the figure, I _total is the total current flowing through the contacts, I _cw is the current flowing through the contact portion between the seed layer and the contacts, and 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 dissolution site on the seed layer side of the shunt current path, and R _deposition is the contact point of the shunt current path. The resistance of the deposition site on the side, R _electrolyte represents the resistance of the plating solution.

When the contact portion between the contact 50 and the seed layer Sd in the sealed space 33 is covered by a liquid Q with high conductivity (for example, a plating liquid or a liquid mixed with a plating liquid), when the resistance R _wafer of the seed layer Sd And/or when the contact resistance _Rcontact between the contact 50 and the seed layer Sd is high, due to the ion conductivity in the liquid Q and the oxidation-reduction reaction on the surface of the seed layer Sd and the surface of the contact 50, the voltage from the seed layer Sd is generated. The shunt current I _shunt flows to the contact 50 via the liquid Q (the shunt of the current I _cw passing through the contact part). The shunt current I _shunt flows because Cu turns into Cu ^{2 +} on the surface of the seed layer Sd and melts into the liquid Q. The Cu ^{2 +} in the liquid Q turns into Cu on the surface of the contact 50 and flows. Therefore, when a shunt current is generated, Cu in the seed layer Sd is dissolved, the seed layer Sd becomes thinner, and the resistance of the seed layer Sd increases, which may cause power supply deviation. This shunt current also occurs when the resistance value of the seed layer Sd is locally increased due to the above-mentioned local battery effect.

As described above, by covering the contact area between the contact and the seed layer with a liquid having a conductivity of 50 μS/cm or less, 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 portion between the contact and the seed layer is increased to 1000 μS/cm, local battery effects and/or shunt currents can be effectively suppressed. Causes corrosion (dissolution) of the seed layer.

5 and 6 are explanatory diagrams illustrating the flow of the control method of the plating device. The control method of the plating apparatus according to this embodiment will be described with reference to these drawings.

In step S11, in the pre-wet module 200, a pre-wet process is performed on the substrate Wf with the seed layer Sd provided on the surface to be plated. In the prewet treatment, the plated surface of the substrate before plating treatment is wetted with the treatment liquid Lp1 such as pure water or degassed water, thereby replacing the air inside the resist pattern Rp formed on the substrate surface with the treatment liquid Lp1. . The pre-wetted substrate Wf is wetted by the processing liquid Lp1, and the openings of the resist pattern Rp on the surface of the substrate Wf are filled with the processing liquid Lp1 (Fig. 5).

In step S12, in the prepreg module 300, a prepreg process is performed on the substrate Wf. In addition, presoaking is sometimes omitted. In the prepreg treatment, for example, a treatment liquid Lp2 such as sulfuric acid or hydrochloric acid is used to remove an 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, and then the plated base is Surface cleaning or activation. In addition, after the pre-soaking process, the substrate Wf may be cleaned with the treatment liquid Lp3 such as pure water or degassed water. The prepreg-processed substrate Wf is wetted by the processing liquid Lp2 (or Lp3), and the openings of the resist pattern Rp on the surface of the substrate Wf are filled with the processing liquid Lp2 (or Lp3) (Fig. 5). In the following description, the processing liquids Lp1, Lp2, and Lp3 may be collectively referred to as the processing liquid Lp.

In step S13, the substrate Wf transported to the plating module 400 is mounted on the substrate holder 30, which is also called a plating head. At this time, as shown in FIG. 5 , the substrate Wf is wetted by the processing liquid Lp (Lp1, Lp2, or Lp3). The contact portion 51 of the contact point 50 of the substrate holder 30 is covered with the coating liquid of the liquid 60 supplied in the cleaning process of steps S15 and/or S17 described below. In addition, the contact portion 51 of the contact 50 indicates a portion of the contact 50 that contacts the seed layer Sd of the substrate Wf (in this example, the end portion of the contact 50 ).

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

In step S15, after the plating process, the substrate holder 30 is raised above the liquid level of the plating liquid Ps in the plating tank 10, and the cleaning liquid supplied from the cleaning liquid nozzle 61 is used to clean the substrate Wf with the cleaning liquid. The plated surface (Figure 6). At this time, the substrate holder 30 and/or the cleaning liquid nozzle 61 may be rotated to apply the cleaning liquid uniformly to the substrate Wf. Through this cleaning process, the plating liquid adhering to the substrate Wf can be recovered and appropriately reused, and/or the plated surface of the substrate Wf can be wetted to prevent the plated surface from drying out. The cleaning liquid can be, for example, pure water, degassed water, or other liquids (liquids used in processes such as prewetting, presoaking, and cleaning). The cleaning liquid used for cleaning is collected in the liquid receiving tray 62 arranged below the substrate Wf, and is discharged through the drain pipe 63 . A conductivity meter 64 may be provided on the liquid receiving tray 62 and/or the drain pipe 63 to measure the conductivity of the recovered cleaning liquid (pure water). In addition, the collected cleaning liquid may be returned to the plating tank 10 and reused after concentration adjustment or without concentration adjustment. For example, the cleaning nozzle 61 and the liquid receiving tray 62 can be configured to move below the substrate holder 30 when the substrate holder 30 rises, and to be retractable from below the substrate holder 30 after the cleaning process.

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 rotary rinsing and drying module 600. After cleaning and drying are performed, the substrate Wf is transported to the cassette of the loading port 100 (step S18).

In step S17 , the contacts 50 and the sealing member 55 of the substrate holder 30 after the substrate Wf is removed are cleaned with a predetermined amount of cleaning liquid 60 supplied from the cleaning nozzle 71 . At this time, the substrate holder 30 is rotated at least once to uniformly supply pure water to the contacts 50 . In addition, if pure water is supplied to the contact point 50 at least once, the cleaning nozzle 71 may be rotated, or both the substrate holder 30 and the cleaning nozzle 71 may be rotated. In this embodiment, by moistening both the substrate Wf side and the substrate holder 30 side, it is possible to ensure that the contact portion between the contact 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 processes such as prewetting, presoaking, and cleaning). The cleaning liquid 60 used for cleaning is collected in the liquid receiving tray 72 arranged below the substrate Wf, and is discharged through the drain pipe 73 . A conductivity meter 74 is provided on the liquid receiving tray 72 and/or the drain pipe 73 , and the conductivity meter 74 measures the conductivity of the recovered cleaning liquid (pure water). 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 fluid is less than a threshold. When the control module 800 determines that the conductivity of the cleaning liquid is above the threshold value, the control module 800 continues the cleaning process. On the other hand, when the control module 800 determines that the conductivity of the cleaning liquid is less than the threshold value, it returns to step S13 and waits until the next substrate Wf is loaded into the plating module 400 to mount the next substrate Wf on the substrate. Holder 30.

The above process is repeated, and the plurality of substrates Wf are sequentially plated. In addition, when the first substrate Wf is plated, or when a certain time elapses from the time when the previously plated substrate Wf is taken out from the plating module 400 , the substrate holder 30 is present. There is a possibility that the contact portion 51 of the contact 50 is dry or incompletely dry. In addition, if time passes from the time when cleaning is completed, carbon dioxide in the atmosphere gradually dissolves into the cleaning liquid on the substrate holder, causing the conductivity to increase and possibly exceed the threshold value. In this case, before the substrate Wf is plated, the process of step S17 is performed to cover the contact portion 51 of the contact 50 of the substrate holder 30 with the liquid 60, and then the wetted substrate is removed in step S13. Wf is attached to the substrate holder 30 .

In this embodiment, as shown in FIG. 6 , the liquid 60 for covering the contact portion of the contact 50 with the substrate Wf can be held in the substrate receiving portion 32B. In addition, in this embodiment, the sealing member 55 (lip portion 55A) functions to suppress or prevent 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 functions 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 portion/storage portion for holding the liquid 60 (however, the liquid 60 does not need to be in contact with the outer peripheral wall 23A). That is, the sealed space (inner space) 33 includes a container part/storage part that holds the liquid 60 . In other words, the holder main body (the first holding member 31 and the second holding member 32 ) includes a container part/storage part or a sealed space (inner space) 33 that holds the liquid 60 .

(protective electrode) It has been found through experiments that in the sealed space 33 of the substrate holder 30, the plating of the substrate Wf (wet contact method) is performed with at least the contact portion of the contact 50 and the seed layer Sd immersed in the liquid, as described above. , if the conductivity of the liquid (for example, pure water) is managed below 50 μS/cm, local battery effects and shunt currents can be suppressed, thereby suppressing or preventing corrosion of the seed layer Sd. In the structure of this embodiment, it is found that by further providing a protective electrode (also called an anti-corrosion electrode) described below, even if the conductivity of the liquid covering the contact 50 is expanded to a range of 1000 μS/cm or less, it is possible to suppress or prevent the substrate from being damaged. Corrosion of the seed layer Sd of Wf. That is, in the wet contact method, by immersing the protective electrodes 238A and 238B (Figs. 7 and 9) in the liquid and disposing them near the seed layer Sd, even when the conductivity of the liquid is high (including a small amount of plating liquid Intrusion into the sealed space), the corrosion of the seed layer Sd can also be effectively suppressed.

(External power supply type) FIG. 7 is a schematic enlarged cross-sectional view showing a part of the substrate holder 30 having the protective electrode 238A according to an example. FIG. 8 is a plan view of the second holding member 32 of the substrate holder 30 having the protective electrode 238A according to an example. In this example, the protective electrode 238A is biased toward the high potential side with respect to the seed layer Sd, so that the protective 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 contact 50 is shown in a structure in which power is supplied via the bus bar 49 arranged in the substrate holder 30 .

In this embodiment, the protective electrode 238A is disposed with an insulating spacer 239 between the protective electrode 238A and the contact 50 . The spacer 239 is a structure for electrically insulating the protective electrode 238A and the contact 50 . If the protective electrode 238A and the contact 50 are separated and arranged to ensure electrical insulation between them, the separator 239 may be omitted, or any other method may be used to ensure electrical insulation between the two. Furthermore, in order to ensure electrical insulation between the protective electrode 238A and the contact 50 in a limited space such as the inner space 33 of the substrate holder 30 , separation by the spacer 239 is effective.

(External power supply type, insoluble protective electrode) The protective electrode 238A is, for example, an insoluble electrode formed of a material whose natural potential (standard electrode potential) is larger (higher) than the material of the seed layer Sd, or coated with such a material. A material with a higher natural potential than the material of the seed layer Sd is 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 that does not cause an excessively large oxygen overvoltage when oxygen is generated due to the electrode reaction when biased to the high potential side, and the material components do not elute or corrode. The material of the protective electrode 238A can be a material generally used as an insoluble electrode for oxygen generation, and can be, for example, Pt, Pt/Ti, Pt/SUS, or IrO2/Ti.

From the viewpoint of suppressing corrosion of the seed layer Sd, the protective electrode 238A is preferably disposed in the vicinity of the seed layer Sd (contact area) in the outer peripheral portion (edge portion) of the substrate Wf, which is highly likely to be corroded, as shown in FIG. 8 . is provided at a position facing the entire circumference of the substrate Wf. The distance between the protective electrode 238A and the edge of the substrate Wf is preferably 10 mm or less, for example. In this figure, the protective electrode 238A is formed continuously over the entire edge circumference of the substrate Wf (the entire circumference of the substrate holder 30 ), but it may be divided and provided corresponding to each block of the contact 50 . In addition, the outer peripheral portion (edge portion) of the substrate Wf refers to, for example, the portion of the substrate arranged in the sealed space 33 when the substrate Wf is held by the substrate holder 30 .

As shown in FIG. 7 , the protective electrode 238A is configured so that at least a part thereof is in contact with the liquid 60 or is 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 contact 50 (seed layer Sd) is connected to the negative electrode of the DC power supply 236 via the bus bar 49 . Thus, by biasing the protective electrode 238A to the high potential side with respect 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 Corrosion (dissolution) of seed layer Sd. The DC power supply 236 is a bias power supply that is driven by a constant voltage or a constant current, and it suffices as long as it can apply a voltage of about 2V between the protective electrode 238A and the seed layer Sd. In one example, DC power supply 236 can use a 1.5V dry cell battery. As the DC power supply, a stabilized power supply generally used in electroplating equipment and the like can also be used. The upper limit voltage value and upper limit current value can be preset for the regulated power supply, constant voltage drive is performed below the upper limit current value, and switched to constant current drive when the upper limit current value is reached. Accordingly, when the conductivity of the liquid 60 rises sharply due to leakage of the plating liquid or the like, it is possible to prevent an excess current from flowing. The voltage of the protective electrode 238A with respect to the seed layer Sd is preferably a voltage that is sufficiently larger than the difference in natural potential between the seed layer Sd and the protective electrode 238A. For example, the difference in natural potential between copper and platinum in a 0.1% dilution (conductivity of about 1000 μS/cm) of a copper sulfate plating solution (50 g/L copper, 100 g/L sulfuric acid, 50 mg/L chlorine) is about 0.5V. Therefore, when the material of the seed layer Sd is copper and the material of the protective electrode 238A is platinum, it is preferable to apply a voltage sufficiently greater than 0.5V.

FIG. 11 is an explanatory diagram illustrating the principle of preventing seed layer corrosion using a protective electrode. The mechanism of preventing corrosion by the insoluble protective electrode 238A is as follows. In the liquid 60, an oxidation reaction of 2H ₂ O → O ₂ +4H ⁺ +4e (decomposition of water) occurs near the protective electrode 238A. On the other hand, in the liquid 60, O ₂ + 4H ⁺ +4e → 2H ₂ O (generation of water), 2H ⁺ +2e → H ₂ (generation of hydrogen), and Cu ^{2 +} +2e → Cu are generated near the seed layer Sd. (when the plating liquid is mixed into the liquid 60). In this way, corrosion of the seed layer Sd is suppressed or prevented by the protective electrode 238A.

That is, even if a gradient of dissolved oxygen concentration occurs in the liquid 60 ( FIG. 20 ), by causing the protective electrode 238A to function as an anode and the seed layer Sd to function as a cathode, the oxidation reaction of Cu in the seed layer Sd can be suppressed, and the oxidation reaction of Cu in the seed layer Sd can be suppressed. Or prevent 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 thickness of the plating film can be suppressed or prevented.

In addition, even if the plating liquid is mixed into the liquid 60 due to leakage of the plating liquid into the internal space 33, the seed layer Sd can be suppressed by causing the protective electrode 238A to function as an anode and the seed layer Sd to function as a cathode. The oxidation reaction of Cu in the copper can inhibit or prevent the corrosion of the seed layer Sd caused by local battery action (Figure 20) and shunt current (Figure 21). Therefore, corrosion of the seed layer Sd can be suppressed or prevented, and a decrease in the uniformity of the thickness of the plating film 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, 4 V or more) between the protective electrode 238A and the contact 50 . Accordingly, even when using a specific substrate in which the surface of the seed layer is covered with a thick oxide film (eg, 50 nm thick), the contact resistance can be stabilized and the corrosion of the seed layer can be prevented from being concentrated near the contact, so it is possible More effectively inhibits corrosion of the seed layer. For example, when such a substrate is used, a large voltage can be applied to reduce the oxide film on the surface of the seed layer before plating or at the beginning of plating, and then the voltage can be reduced to a voltage sufficient to prevent corrosion of the seed layer to perform plating. Overwrite processing. In addition, like the oxide film on the surface of the seed layer, even when an oxide film exists at the contact end, it can be reduced to metal. For example, it is effective in the case where metal from the seed layer adheres to the contact end and is oxidized due to long-term use. This operation can be performed even when the substrate Wf is not present, and therefore can be performed during idling when no plating process is performed. By reducing the oxide film at the contact end, the contact resistance increased due to the formation of the oxide film can be improved.

(External power supply type, soluble protective electrode) As the material of the protective electrode 238A, a material whose natural potential (standard electrode potential) is approximately the same as the material of the seed layer Sd may be used. In this case, the DC power supply 236 biases the protective electrode 238A to the high potential side with respect to the seed layer Sd, thereby dissolving the protective electrode 238A prior to the seed layer Sd, and the protective electrode 238A serves as a sacrificial electrode (soluble electrode). ) function. 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 be a conductor made of the same material as the plated metal. For example, like the soluble anode, an electrode made of phosphorus-containing copper can be used. In addition, as the material of the protective electrode 238A, a material having a smaller (lower) natural potential than the seed layer Sd may be used. In this case, it is considered that the protective electrode 238A is more easily dissolved and its function as a sacrificial electrode is improved.

The mechanism of preventing corrosion by the soluble protective electrode 238A is as follows. As shown in FIG. 11 , in the liquid 60 , an oxidation reaction of M→M ^{n ++} ne (for example, Cu→Cu ^{n ++} ne) occurs near the soluble protective electrode 238A. On the other hand, in the liquid 60, O ₂ + 4H ⁺ +4e → 2H ₂ O (generation of water), 2H ⁺ +2e → H ₂ (generation of hydrogen), and Cu ^{2 +} +2e → Cu are generated near the seed layer Sd. reduction reaction. In this way, the soluble protective electrode 238A has priority in dissolving Cu in the seed layer Sd, and can suppress or prevent corrosion of the seed layer Sd.

That is, even if a gradient of dissolved oxygen concentration occurs in the liquid 60 ( FIG. 20 ), the soluble protective electrode 238A dissolves prior to the seed layer Sd, thereby suppressing or preventing the corrosion of the seed layer Sd caused by the local battery action. Therefore, corrosion of the seed layer Sd can be suppressed or prevented, and a decrease in the uniformity of the thickness of the plating film can be suppressed or prevented.

In addition, even if the plating liquid is mixed into the liquid 60 due to leakage of the plating liquid into the internal space 33, the soluble protective electrode 238A is dissolved prior to the seed layer Sd, thereby suppressing or preventing the local battery action (Fig. 20) and the corrosion of seed layer Sd caused by shunt current (Fig. 21). Therefore, corrosion of the seed layer Sd can be suppressed or prevented, and a decrease in the uniformity of the thickness of the plating film can be suppressed or prevented.

(leak detection) In either of the insoluble and soluble protective electrodes 238A, the current detector 237 may be provided in 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 protective electrode 238A and the contact 50 (or the bus bar 49 ) or the resistance between them. The current flowing between the protective electrode 238A and the contact point 50 (or the bus bar 49 ) corresponds to the current flowing in the liquid 60 in the internal space 33 . The resistance between the protective electrode 238A and the contact point 50 (bus bar 49 ) is equivalent to the resistance of the liquid 60 in the internal space 33 .

The application of DC voltage to the protective electrode 238A and the detection of current (resistance) are controlled by the control module 800 . The control module 800 obtains the current flowing in the protective electrode 238A (the current flowing in the liquid 60 in the internal space 33 ) through the current detector 237 , and detects the leakage of the plating liquid into the internal space 33 based on this current. Instead or based on this, the control module 800 obtains the current flowing in the protective electrode 238A, calculates the resistance value of the liquid 60 based on the voltage between the protective electrode 238A and the contact 50 (bus bar 49) and the detected current, and Leak detection based on resistance value.

In the case where the plating liquid does not leak into the internal space 33 , since the resistance of the liquid 60 in the internal space 33 is extremely high, no current flows between the protective electrode 238A and the contact 50 (bus bar 49 ), or The anti-corrosion current accompanying the decomposition and generation reaction of water and the generation reaction of hydrogen flows from the protective electrode 238A to the contact 50 (bus bar 49 ), but is very small compared with the current flowing when the plating solution leaks. On the other hand, when leakage occurs, the plating liquid is mixed into the liquid 60 , the resistance of the liquid 60 decreases, and a current flows (or the current increases) between the protective electrode 238A and the contact 50 (bus bar 49 ). In this way, the leakage of the plating liquid into the internal space 33 can be detected by the protective electrode 238A.

In this structure, by monitoring the current (resistance) between the protective electrode 238A and the contact 50 (bus bar 49 ), it is possible to detect in advance whether the plating liquid leaks into the internal space 33 . Therefore, even if the leakage of the plating liquid occurs, the leakage of the plating liquid can be detected in advance through the protective electrode 238A, and the abnormality of the substrate holder 30 and the replacement timing of the seal can be detected in advance. In addition, even if the plating solution leaks in an amount that may corrode the seed layer Sd, the dissolution of Cu is also suppressed by the protective electrode 238A as described above, thereby suppressing or preventing corrosion of the seed layer. Therefore, leakage of the plating solution can be detected in advance, thereby suppressing or preventing a decrease in the uniformity of the thickness of the plating film. It is also possible to divide the protective electrode 238A into a plurality of pieces corresponding to each block of the contact 50 and arrange them, and connect each piece to an independent DC power supply 236 and current detector 237 to apply a DC voltage and supply the plating solution. Leak detection. This makes it possible to specify the location where leakage of the plating liquid occurs to a certain extent, and by individually controlling the anti-corrosion current flowing through each block, even when leakage of the plating liquid occurs, it is possible to more effectively Suppresses corrosion of seed layer Sd.

In addition, in FIG. 7 , a DC voltage from a DC power supply 236 is applied between the protective electrode 238A and the contact point 50 (bus bar 49 ), and the DC current is detected by the current detector 237 . However, an AC power supply may also be used. Instead of the DC power supply 236, a current detector monitors the AC current or impedance between the protective electrode 238A and the contact point 50 (bus bar 49) to detect leakage.

In addition, the current detector 237 (leakage detection) may be omitted and the protective electrode 238A may be used only as an electrode for preventing corrosion of the seed layer.

(Direct connection type, soluble protective electrode) FIG. 9 is a schematic enlarged cross-sectional view showing a part of the substrate holder 30 having the protective electrode 238B according to another example. FIG. 10 is a plan view of the second holding member 32 of the substrate holder 30 having the protective electrode 238B according to another example. In this example, as the protective electrode 238B, an electrode made of a material that is easier to become an anode (a material that has a small (low) natural potential) than the material of the seed layer Sd is used as a sacrificial electrode. In this example, by utilizing the natural potential difference 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 contact 50 is shown in a structure in which power is supplied via the bus bar 49 arranged in the substrate holder 30 .

As shown in FIG. 9 , the protective electrode 238B is fixed to the contact point 50 to be electrically connected thereto, and is electrically connected to the seed layer Sd via the contact point 50 . The protective electrode 238B is a soluble electrode made of a material whose natural potential (standard electrode potential) is smaller than the material of the seed layer Sd. A material with a lower natural potential than the material of the seed layer Sd refers to a material with a lower natural potential than the material of the seed layer Sd, and is a material that is easier to serve as an anode than the material of the seed layer Sd. When the seed layer Sd is Cu, the material of the protective electrode 238B can be selected from Al, Zn, Fe, etc., for example. Among them, the natural potential of Zn is the lowest (relative to Cu (approximately -1.1V), the seed layer has a high corrosion inhibition effect. In addition, the protective electrode 238B may be electrically connected to the seed layer Sd via a conductor other than the contact point 50 , or may be electrically connected to the contact point 50 via a conductor other than the contact point 50 . In addition, when the substrate Wf is held by the substrate holder 30, the protective electrode 238B may be in direct contact with the seed layer Sd and be electrically connected. When the protective electrode 238B is directly fixed to the contact 50 as in this embodiment, the structure for installing the protective electrode 238B in the sealed space 33 can be simplified.

From the viewpoint of suppressing corrosion of the seed layer Sd, the protective electrode 238B is preferably disposed in the vicinity of the seed layer Sd (contact area) in the outer peripheral portion (edge portion) of the substrate Wf, which is highly likely to be corroded. As shown in FIG. 10 , essentially is provided at a position facing the entire circumference of the substrate Wf. The distance between the protective electrode 238B and the edge of the substrate Wf is preferably 10 mm or less, for example. In this figure, the protective electrode 238B is divided and provided corresponding to each block of the contact 50 . However, it may be provided continuously over the entire edge circumference of the substrate Wf (the entire circumference of the substrate holder 30 ).

As shown in FIG. 9 , the protective electrode 238B is arranged so that at least a part thereof is in contact with or immersed in the liquid 60 (pure water, etc.). The protective electrode 238B has a smaller natural potential than the seed layer and is electrically connected to the seed layer Sd via the contact point 50 . Therefore, it functions as a sacrificial electrode that dissolves prior to the seed layer Sd and serves as an anti-corrosion electrode that suppresses corrosion of the seed layer Sd. The electrode (anti-corrosion electrode) functions.

The mechanism of preventing corrosion by using the protective electrode 238B having a lower natural potential than the seed layer Sd is equivalent to the case where the DC power supply 236 is omitted and the protective electrode 238A and the contact 50 are short-circuited in FIG. 11 . As shown in FIG. 11 , in the liquid 60 , an oxidation reaction of M → M ^{n +} +ne (for example, Al → Al ^{3 +} +3e) occurs near the protective electrode 238B, and 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, O ₂ + 4H ⁺ +4e → 2H ₂ O (generation of water), 2H + 2e → H ₂ (generation of hydrogen), Cu ^{2 +} +2e → Cu (in the liquid 60 (when the plating solution is mixed with the plating solution). In this way, the protective electrode 238B is dissolved prior to the seed layer Sd, thereby suppressing or preventing corrosion of the seed layer Sd.

That is, even if a gradient of dissolved oxygen concentration occurs in the liquid 60 ( FIG. 20 ), the soluble protective electrode 238B dissolves prior to the seed layer Sd, thereby suppressing or preventing the corrosion of the seed layer Sd caused by the local battery action. Therefore, corrosion of the seed layer Sd can be suppressed or prevented, and a decrease in the uniformity of the thickness of the plating film can be suppressed or prevented.

In addition, even if the plating liquid is mixed into the liquid 60 due to the leakage of the plating liquid into the internal space 33, the soluble protective electrode 238B is dissolved prior to the seed layer Sd, thereby suppressing or preventing the local battery action (Fig. 20) and the corrosion of seed layer Sd caused by shunt current (Fig. 21). Therefore, corrosion of the seed layer Sd can be suppressed or prevented, and a decrease in the uniformity of the thickness of the plating film can be suppressed or prevented.

According to the protective electrode 238B according to this example, an external power supply for biasing the protective electrode 238B is not required, so the structure of the plating module can be simplified. In addition, the surface of the protective electrode 238B is preferably covered with an anode bag, a separator, or the like. This can prevent the oxides and hydroxides generated on the surface of the protective electrode 238B during corrosion from falling off the electrode surface and contaminating the inside of the substrate holder 30 .

(Power-on test model) FIG. 12 is a schematic diagram showing an energization test model for testing the effect of the protective electrode. FIG. 13 is a photograph showing the structure of the energization test model, and FIG. 14 is a partially enlarged photograph of the energization test model. In this energization test model, as shown in FIG. 12 , an insoluble protective electrode 238A is used, and the protective electrode 238A is biased toward the high potential side with respect to the contact 50 (seed layer Sd) by the DC power supply 236 . In addition, in the energization test, a Pt wire (diameter: 0.4 mm) was used as the protective electrode 238A. In addition, a current corresponding to the plating current is caused to flow between the contact point 50 and the portion of the seed layer Sd away from the contact point 50 by the DC power supply 90 to perform a current conduction test. That is, instead of causing the plating current to flow between the seed layer Sd of the substrate Wf and the anode 16 ( FIG. 3 ), a current simulating the plating current flows between the connection portion of the seed layer Sd connected to the contact point 50 and away from the contact point. 50 flows between the parts, thereby performing a current-carrying test modeling the plating process. In addition, a blank wafer (Blanket Wafer) on which a pattern such as a resist pattern is not formed is used as the substrate Wf. The contact portion between the contact 50 and the seed layer Sd and a part of the protective electrode 238A are covered with the liquid 60 to perform a current conduction test.

Figures 13 and 14 show photos of the actual energization test model. As shown in these figures, the patternless wafer as the substrate Wf is clamped and fixed from above and below by the jig 901 , and one end of the substrate Wf is in contact with the contact 50 . Contact 50 is held by clamp 902. The other end of the substrate Wf and the contact 50 are connected to the positive electrode and the negative electrode of the DC power supply 90 respectively. In addition, as shown in FIG. 14 , a protective electrode 238A made of a Pt wire is arranged below the contact 50 . One end of the Pt wire is bent into an L shape and is led upward from the gap of the contact 50 . As shown in FIG. 13 , the lead-out portion of the protective electrode 238A and the contact point 50 are connected to the positive electrode and the negative electrode of the DC power supply 236 respectively. The gap 903 between the clamps 901 and 902 is filled with liquid 60 (pure water in this example).

In addition, for comparison, in the structure of the energization test model shown in FIGS. 12 to 14 , a energization test was also performed in a structure in which the protective electrode 238A was omitted. FIG. 15 is a photograph showing the results of the energization test when the protective electrode was provided, and FIG. 16 is a photograph showing the results of the energization test when the protective electrode was not provided. As can be seen from these figures, when the protective electrode is not provided, corrosion occurs in the seed layer Sd (FIG. 16). However, by providing the protective electrode 238A, corrosion of the seed layer Sd can be suppressed (FIG. 15).

(Second Embodiment) FIG. 17 is a schematic diagram for explaining the structure of the plating module of the plating apparatus according to the second embodiment. The plating module of this embodiment is a vertical (also called immersion type, panel type) plating module in which a substrate is plated in a vertical direction. As shown in this figure, the plating module 400 includes a plating tank 10 holding a plating liquid inside, and an anode 16 disposed in the plating tank 10 to face the substrate holder 30 . The anode 16 is held by an anode holder 60 and disposed in the plating tank 10 . The substrate holder 30 is configured to detachably hold a substrate Wf such as a wafer, and to immerse the substrate Wf in the plating liquid Ps in the plating tank 10 . The anode 16 is connected to the positive electrode of the DC power supply 90 via the anode holder 60 , and the substrate Wf is connected to the negative electrode of the DC power supply 90 via the substrate holder 30 . When a voltage is applied between the anode 16 and the substrate Wf, a 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 liquid. The substrate Wf may be in any shape such as a circle, a quadrilateral, or other polygonal shapes.

The plating module 400 further includes an overflow tank 20 adjacent to the plating tank 10 . The plating liquid in the plating tank 10 crosses the side wall of the plating tank 10 and flows 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 line 58a. For example, a circulation pump 58b, a thermostatic unit 58c, and a filter 58d are installed in the circulation line 58a. The plating module 400 further includes: a regulation plate (regulation plate) 14 having an opening 14a for adjusting the potential distribution on the substrate Wf; and a paddle 15 for stirring the plating liquid Ps so that the electric potential distribution on the substrate Wf is During plating, sufficient metal ions are uniformly supplied to the surface of the substrate Wf. In addition, the above-mentioned structure is an example, and the structure of the plating module 400 etc. may adopt other structures.

In the vertical plating module, the substrate Wf held by the substrate holder 30 is carried into the plating module 400 after being processed by the prewet module 200 and the prepreg module 300 . As shown in FIG. 18 , the substrate holder 30 includes a front plate 210 and a back plate 220 , and the front plate 210 and the back plate 220 sandwich and hold the substrate Wf. A sealed space (inner space) 33 closed by the inner seals 215 and 225 and the outer seal 216 is formed between the front plate 210 and the rear plate 220 of the substrate holder 30 .

As shown in FIG. 18 , the rear plate 220 is provided with an introduction passage 231 and a discharge passage 232 that communicate the internal space 33 of the substrate holder 30 with the outside of the substrate holder 30 . In FIG. 18 , for convenience, the introduction passage 231 and the discharge passage 232 are shown as one structure, but they are mutually independent structures. The introduction passage 231 and the discharge passage 232 are respectively provided with a valve 231A and a valve 232A for controlling on and off of each passage. Valve 231A and valve 232A are controlled by control module 800 . The liquid can be introduced into the internal space 33 of the substrate holder 30 by, for example, immersing the substrate holder 30 holding the substrate Wf in the liquid in the processing tank of the pre-wetting module 200 in the pre-wetting process before the plating process. liquid, such as pure water), open the valve 231A of the introduction passage 231 , introduce pure water into the internal space 33 of the substrate holder 30 via the introduction passage 231 , and fill the internal space 33 with pure water. Alternatively, the substrate holder 30 holding the substrate Wf may be immersed in the liquid in the processing tank, and the valves 231A and 232A may be opened to introduce pure water into the internal space 33 while exhausting air and pure water from the internal space 33. Pure water fills the interior space33. It is preferable that the internal space 33 is completely filled with pure water so that no air remains. However, some air or bubbles may be allowed to remain depending on the degree of desired effects described below. In addition, the example in which pure water is introduced into the internal space of the substrate holder in the prehumidification module has been described. However, pure water can also be introduced into the internal space of the substrate holder in other modules, and a device for holding the substrate can also be provided. Other modules that introduce liquids such as pure water into the internal space of the container.

(External power supply type, insoluble protective electrode) 18 shows a structure in which the insoluble protective electrode 235A is biased toward the high potential side with respect to the contact 50 (seed layer Sd) in the internal space 33 of the substrate holder 30 of the vertical plating module 400. As described above, the internal space 33 is filled with a liquid (eg, pure water) composed of, for example, the processing liquid of the prewet module 200 or the like. This structure is equivalent to applying the example of using the insoluble protective electrode 238A in the embodiment of FIGS. 7 and 8 to a structure of a vertical plating module. According to this configuration, as described with reference to FIGS. 7 and 8 , by causing the protective electrode 238A to function as an anode and the seed layer Sd to function as a cathode, the oxidation reaction of Cu in the seed layer Sd can be suppressed, and the seeding can be suppressed or prevented. Corrosion of layer Sd. Therefore, corrosion of the seed layer Sd can be suppressed or prevented, and a decrease in the uniformity of the thickness of the plating film can be suppressed or prevented.

(External power supply type, soluble protective electrode) In the embodiment shown in FIG. 18 , similarly to the embodiments in FIGS. 7 and 8 , a material whose natural potential (standard electrode potential) is approximately the same as that of the seed layer Sd may be used as a material for the protective electrode 235A. Or a material having a lower natural potential (standard electrode potential) than the material of the seed layer Sd. In this case, the DC power supply 236A biases the protective electrode 235A to the high potential side with respect to the seed layer Sd, thereby dissolving the protective electrode 235A prior to the seed layer Sd, and the protective electrode 235A serves as a sacrificial electrode (soluble electrode). ) function. The material of the protective electrode 235A can be, for example, the same material as the seed layer Sd (the same material as the plating metal). According to this configuration, as described with reference to FIGS. 7 and 8 , the soluble protective 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 a decrease in the uniformity of the plating film thickness can be suppressed or prevented.

In the embodiment shown in FIG. 18 , as described in the embodiment of FIGS. 7 and 8 , the current detector 237A may be used to monitor the path between the protective electrode 235A and the contact 50 (bus bar 49 ). The current flowing through the liquid 60 or the resistance between them detects the leakage of the plating liquid Ps into the internal space 33 . Furthermore, in the example of FIG. 18 , the protective electrode 235A may not be used for leak detection, but the protective electrode 235A may be used only as an electrode for preventing corrosion of the seed layer Sd. In addition, in FIG. 18 , a DC voltage from a DC power supply (DC power supply) 236A is applied between the protective electrode 235A and the contact 50 (bus bar 49 ), and the DC current is detected by the current detector 237A. However, it may also be used. An alternating current power supply (AC power supply) is used instead of the DC power supply 236A, and a current detector monitors the AC current or impedance between the protective electrode 235A and the contact 50 (bus bar 49) to detect leakage.

(Direct connection type, soluble protective electrode) Figure 19 shows a structure in which the soluble protective electrode 235B is connected to the contact point 50 in the internal space of the substrate holder of the vertical plating module. That is, the protective electrode 235B is fixed to the contact point 50 and connected to the seed through the contact point 50. The layer Sd is electrically connected. In addition, the protective electrode 235B may be electrically connected to the seed layer Sd via a conductor other than the contact point 50 , or may be electrically connected to the contact point 50 via a conductor other than the contact point 50 . In addition, when the substrate Wf is held by the substrate holder 30, the protective electrode 235B may be in direct contact with the seed layer Sd and be electrically connected. This structure is equivalent to applying the embodiment of FIGS. 9 and 10 to a vertical plating module. According to this configuration, as described with reference to FIGS. 9 and 10 , the soluble protective electrode 235B 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 a decrease in the uniformity of the thickness of the plating film can be suppressed or prevented.

In addition, in FIGS. 18 and 19 , the structure of the 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 the substrate holder for single-sided plating. It may be a substrate holder for double-sided plating, or it may be a substrate holder for single-sided plating in which only one side of the substrate Wf is exposed.

According to the above-described embodiment, since the internal space 33 of the substrate holder 30 is filled with liquid (for example, pure water), the pressure difference between the inside and the outside of the internal space 33 is reduced compared to the case where the internal space 33 is hollow. , the leakage of the plating liquid into the internal space 33 can be suppressed or prevented. This can suppress or prevent a decrease in the uniformity of the thickness of the plating film due to leakage of the plating solution.

According to the above embodiment, even if the leakage of the plating liquid occurs, since the internal space 33 is filled with the liquid (for example, pure water), the intrusion of the plating liquid into the internal space 33 is limited to the amount of diffusion and is suppressed to a very small amount. , it is possible to suppress dissolution (corrosion) of the seed layer Sd caused by local cell action and/or shunt current due to dissolved oxygen concentration. In addition, since the plating liquid that invades the internal space 33 is diluted by the liquid (for example, pure water), corrosion of the seed layer Sd can be further suppressed. This can suppress or prevent a decrease in the uniformity of the thickness of the plating film.

In addition, according to the above-described embodiment, since the internal space 33 is filled with liquid (for example, pure water) and has a low oxygen concentration, dissolution of the seed layer Sd due to local battery action caused by dissolved oxygen can be suppressed. This can suppress or prevent a decrease in the uniformity of the thickness of the plating film.

In addition, according to the above-described embodiment, even if the leakage of the plating liquid in an amount that may corrode occurs, the dissolution of the seed layer Sd can be suppressed or prevented by the protective electrodes 235A and 235B. This can suppress or prevent a decrease in the uniformity of the thickness of the plating film due to leakage of the plating solution.

[Other embodiments] (1) In the above embodiment, a resist pattern is taken as an example as a pattern on the substrate, but the pattern may be a pattern of vias or trenches for forming wiring, or a pattern of Patterns of resists or insulating films used to form bumps, redistribution, and electrode pads, and any pattern that defines the shape of other plating films. (2) The liquid introduced into the internal space of the substrate holder may be a liquid other than water as long as it does not corrode the structural members exposed in the internal space of the substrate holder. For example, a liquid that does not contain a metal salt (a liquid in which the concentration of the metal salt is less than a predetermined concentration (for example, 5 g/L)) can be used. Examples of such liquids include tap water, natural water, and pure water. Pure water includes, for example, deionized water (DIW), distilled water, purified water or RO water. (3) The structure of the substrate holder is not limited to the above example. The above embodiment can be applied to a substrate holder with any structure as long as it has an internal space for sealing the contacts.

At least the following aspects can be understood from the above embodiments. [1] According to one aspect, there is provided a substrate holder for holding a substrate and bringing the substrate into contact with a plating liquid to perform plating, and having a contact for contacting a seed formed on the surface of the substrate. layer contact and power supply; the protective electrode has a material that is biased toward the high potential side relative to the above-mentioned contact point, or has a lower natural potential than the above-mentioned seed layer, and the protective electrode is directly connected to the above-mentioned seed layer at the above-mentioned contact point or electrically connected via a conductor; and a holder body having an internal space that seals the outer peripheral portion of the substrate and the above-mentioned substrate from the outside of the substrate holder while the substrate is held by the substrate holder. The contact and the protective electrode are accommodated, and a liquid covering at least a part of the protective electrode and a contact portion between the seed layer and the contact is retained. "The liquid covering at least a part of the protective electrode and the contact portion between the seed layer and the contact point" includes: the entire protective electrode is covered with the liquid; and the entire seed layer arranged in the internal space Covered by the liquid; the entire contact point is covered by the liquid; and/or the entire internal space is covered by the liquid.

According to this method, the liquid near the protective electrode or the material of the protective electrode is oxidized prior to the material of the seed layer, and the material of the seed layer can be suppressed from being dissolved in the liquid. Therefore, corrosion (deterioration) of the seed layer can be suppressed or prevented. The local cell action on the surface of the seed layer caused by the dissolved oxygen concentration gradient in the liquid covering the contacts and the like can be suppressed, thereby suppressing or preventing corrosion of the seed layer. In addition, even when the plating liquid invades the internal space of the substrate holder, corrosion of the seed layer caused by the local cell effect and/or the shunt current can be suppressed or prevented. Since the deterioration of the seed layer can be suppressed by the protective electrode, the uniformity of the thickness of the plating film can be suppressed or prevented from decreasing.

[2] According to one aspect, the protective electrode is an insoluble electrode and is biased toward a high potential side with respect to the contact point.

According to this aspect, periodic replacement of the protective electrode may not be required or the frequency of replacement of the protective electrode may be reduced, so maintenance of the protective electrode is easy. In addition, it is possible to reduce the possibility that the electrode material (metal) dissolved from the protective electrode is brought into the plating solution and contaminates the plating solution. In addition, it is possible to reduce the possibility that oxides of the electrode material dissolved from the protective electrode precipitate on the contacts and seals and contaminate them.

[3] According to one aspect, a voltage that is sufficiently larger than a difference in natural potential between the protective electrode and the seed layer is applied between the protective electrode and the seed layer.

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

[4] According to one embodiment, the protective electrode is fixed to the contact via a spacer.

According to this aspect, the protective electrode can be easily and appropriately installed in the narrow sealed space in the substrate holder.

[5] According to one aspect, 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.

According to this method, an external power supply for biasing the guard electrode is not required, and the structure of the substrate holder and/or the plating module can be simplified.

[6] According to one aspect, the protective electrode is fixed to the contact point and is electrically connected to the seed layer via the contact point.

According to this aspect, the protective electrode is directly fixed to the contact point and the protective electrode is electrically connected to the seed layer via the contact point. Therefore, the structure for connecting the protective electrode can be simplified.

[7] According to one aspect, the protective electrode is a soluble electrode and is biased toward a high potential side with respect to the contact point.

In this aspect, if the same material as that of 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 metal dissolved from the protective electrode is brought into the plating solution, the possibility of contaminating the plating solution can be reduced.

[8] According to one embodiment, the protective electrode is fixed to the contact via a spacer.

According to this aspect, the protective electrode can be easily and appropriately installed in the limited and narrow sealed space in the substrate holder.

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

According to this aspect, the protective electrode can be disposed over the entire circumference of the outer peripheral portion (edge portion) of the substrate that is highly likely to be corroded, thereby effectively suppressing corrosion of the seed layer.

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

According to this aspect, since the protective electrode is disposed near the edge of the substrate, the seed layer in the outer peripheral portion (edge portion) of the substrate, which is highly likely to be corroded, can be effectively protected from corrosion.

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

This method allows the conductivity of the liquid covering the contacts to reach 1000 μS/cm. It is known that in the wet contact method of plating a substrate while covering the contacts of the substrate holder with a liquid, it is necessary to control the conductivity of the liquid to 50 μS/cm or less without using a protective electrode. On the other hand, when a protective electrode is used, the corrosion of the seed layer can be suppressed by the protective electrode, and therefore the management of the electrical conductivity of the liquid covering the contacts and the like can be significantly relaxed.

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

According to this method, pure water such as DIW commonly used in plating equipment can be used as the liquid for covering the contacts and the like, and there is no need to prepare a separate liquid for covering the contacts and the like.

[13] According to one aspect, the protective electrode functions as a detector, and the detector is configured to monitor the contact point or a wiring electrically connected to the contact point in a state where the liquid is introduced into the internal space. The current flowing between the electrode and the electrode can detect the leakage of the plating liquid into the internal space. "Wiring electrically connected to the above-mentioned contact point" is, for example, a bus bar.

According to this method, the presence or absence of leakage of the plating solution can be detected by monitoring the current flowing between the protective electrode and the contact, etc., so there is no need to separately provide an electrode for leakage detection.

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

According to this method, the above structure can be applied to the substrate holder for horizontal and vertical plating modules, and the above effects can be achieved.

[15] According to one aspect, there is provided a plating device, which includes: a substrate holder in any one of the aspects 1 to 14; a liquid supply module that supplies liquid to the internal space of the substrate holder; and a plating device. The mold assembly makes the substrate held by the substrate holder come into contact with a plating liquid to perform plating on the substrate. The liquid supply module can be composed of a cleaning nozzle, a treatment module using liquid (eg, a prewet module), and the like.

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

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

According to this aspect, by cleaning the internal space of the substrate holder before plating each substrate, the liquid can be retained in the internal space. Thereby, the contacts etc. in the internal space of the substrate holder can always be covered with clean liquid, and substrate plating can be performed.

[17] According to one aspect, the invention further includes a pre-wetting module for pre-wetting the substrate, and the plating module holds the substrate in a wet state in the substrate holder.

According to this method, the pre-wetted substrate can be carried into the plating module in a wet state and held in the substrate holder, without the need for a drying process at the edge of the substrate.

[18] According to one aspect, a method for plating a substrate is provided, including: preparing a substrate holder equipped with a protective electrode, the protective electrode having a material that is opposite to a seed formed on the surface of the substrate The contact point that contacts and supplies power is biased toward the high potential side, or has a lower natural potential than the seed layer of the substrate. The protective electrode is electrically connected to the seed layer directly or via a conductor; the protective electrode is sealed from the outside. A liquid is introduced into the internal space of the substrate holder housed in the outer peripheral portion of the substrate, and in the internal space, at least a part of the protective electrode and the contact point of the substrate holder are brought into contact with the seed layer of the substrate. The contact parts are covered; and the substrate held in the substrate holder is plated in a state where the liquid is introduced into the internal space of the substrate holder.

The embodiments of the present invention have been described above. However, the above-described embodiments of the present invention are for easy understanding of the present invention and do not limit the present invention. It goes without saying that the present invention can be changed and improved without departing from the gist thereof, and equivalents thereof are also included in the present invention. In addition, within the scope that can solve at least part of the above problems or achieve at least part of the effects, the embodiments and modifications can be combined arbitrarily, and the components described in the patentable scope and the specification can be arbitrarily combined. Combine or omit.

U.S. Patent No. 7727366 (Patent Document 1), U.S. Patent No. 8168057 (Patent Document 2), Japanese Patent Application Laid-Open No. 2020-117763 (Patent Document 3), Japanese Patent Application Laid-Open No. 2020-117765 (Patent Document 4) ), including the specification, patent scope, drawings, and abstract, is hereby incorporated by reference in its entirety. The entire disclosure content of International Patent Application No. 2021/038404 and International Patent Application No. 2021/000460, including the specification, patent scope, drawings and abstract, is incorporated into this application by reference in its entirety.

10:Plating tank 20: Overflow tank 14:Adjustment plate 15: paddle 16:Anode 17: Resistor 30:Substrate holder 31: First holding component 32: Second holding component 33: Sealed space (internal space) 40: Rotating mechanism 41:Rotation axis 45:Tilt mechanism 46:Lifting mechanism 47: Pivot 49:Busbar 50:Contact 55:Sealing parts 55A: Lips 60: Cleaning fluid (pure water) 90: DC power supply 215, 225: Inner seal 216: Outer seal 100:Loading port 110:Conveyor robot arm 120:Aligner 200: Pre-wet module 210:Front panel 220:Rear panel 231:Import path 231A:Valve 232:Exhaust passage 232A:Valve 235A, 235B: Protective electrode 236A: DC power supply 238A, 238B: Protective electrode 300:Prepreg module 400: Plating module 500:Cleaning module 600: Rotating flushing and drying module 700:Conveyor device 800:Control module 801:CPU 802:Storage Department 1000:Plating device Wf: substrate Sd: seed layer Ps: plating solution Rp: resist

FIG. 1 is a perspective view showing the overall structure of a plating apparatus according to one embodiment. FIG. 2 is a plan view showing the overall structure of a plating device according to one embodiment. 3 is a schematic diagram illustrating the structure of a plating module of a plating device according to one embodiment. FIG. 4 is a schematic enlarged cross-sectional view showing a part of the substrate holder according to one embodiment. FIG. 5 is an explanatory diagram illustrating the flow of a method of controlling a plating apparatus. FIG. 6 is an explanatory diagram illustrating the flow of a method of controlling a plating apparatus. 7 is a schematic enlarged cross-sectional view showing a part of the substrate holder having a protective electrode according to an example. 8 is a plan view of a second holding member of the substrate holder having a protective electrode according to an example. 9 is a schematic enlarged cross-sectional view showing a part of a substrate holder having a protective electrode according to another example. 10 is a plan view of a second holding member of a substrate holder having a protective electrode according to another example. FIG. 11 is an explanatory diagram illustrating the principle of preventing seed layer corrosion using a protective electrode. FIG. 12 is a schematic diagram showing the structure of the energization test model. FIG. 13 is a photograph showing the structure of the energization test model. FIG. 14 is an enlarged photograph of a part of the energization test model. FIG. 15 is a photograph showing the results of the energization test when a protective electrode was installed. FIG. 16 is a photograph showing the results of the energization test without providing a protective electrode. FIG. 17 is a schematic diagram for explaining the structure of the plating module of the plating apparatus according to the second embodiment. FIG. 18 shows a structure in which an insoluble or soluble protective electrode is biased toward the high potential side with respect to the contact point in the internal space of the substrate holder of the vertical plating module. FIG. 19 shows a structure in which a soluble protective electrode is connected to a contact in the internal space of the substrate holder of the vertical plating module. FIG. 20 is an explanatory diagram illustrating dissolution of the seed layer due to dissolved oxygen concentration. FIG. 21 is an explanatory diagram illustrating the dissolution of the seed layer caused by the shunt current. FIG. 22 is an equivalent circuit diagram illustrating the shunt current.

30:Substrate holder

32: Second holding component

32A: Peripheral wall

32B:Substrate receiving department

33: Sealed space (internal space)

49: bus bar

50: contact

55:Sealing parts

55A: Lips

60: Cleaning fluid (pure water)

236:DC power supply

237:Current detector

238A: Protective electrode

239:Isolation piece

800:Control module

Wf: substrate

Sd: seed layer

Rp: resist

Claims (18)

A substrate holder, the substrate holder is used to hold a substrate and bring the substrate into contact with a plating liquid to perform plating, wherein it is provided with: A contact for contacting and supplying power to the seed layer formed on the surface of the substrate; A protective electrode having a material that is biased toward the high potential side relative to the contact point or has a lower natural potential than the above-mentioned seed layer, and the aforementioned protective electrode is electrically connected to the above-mentioned seed layer directly or via a conductor; as well as The holder main body has an internal space that seals the outer peripheral portion of the substrate and the contact point from the outside of the substrate holder while the substrate is held by the substrate holder. The protective electrode is accommodated, and a liquid covering at least a part of the protective electrode and a contact portion between the seed layer and the contact point is retained. The substrate holder according to claim 1, wherein, The protective electrode is an insoluble electrode and is biased toward a high potential side with respect to the contact point. The substrate holder according to claim 2, wherein, A voltage greater than a difference in natural potential between the protective electrode and the seed layer is applied between the protective electrode and the seed layer. The substrate holder according to claim 2, wherein, The protective electrode is fixed to the contact via a spacer. The substrate holder according to claim 1, wherein, 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. The substrate holder according to claim 5, wherein, The protective electrode is fixed on the contact point and is electrically connected to the seed layer through the contact point. The substrate holder according to claim 1, wherein, The protective electrode is a soluble electrode and is biased toward a high potential side with respect to the contact point. The substrate holder according to claim 7, wherein, The protective electrode is fixed to the contact via a spacer. The substrate holder according to any one of claims 1 to 8, wherein, The protective electrode is continuously or discontinuously provided at a location surrounding the outer periphery of the substrate when the substrate holder holds the substrate. The substrate holder according to any one of claims 1 to 8, wherein, 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 is equal to or less than a predetermined distance. The substrate holder according to any one of claims 1 to 8, wherein, The liquid has an electrical conductivity of 1000 μS/cm or less. The substrate holder according to any one of claims 1 to 8, wherein, The liquid is pure water, or pure water that has been degassed or replaced with inert gas. The substrate holder according to any one of claims 1 to 8, wherein, The guard electrode functions as a detector, The detector is configured to monitor a current flowing between the contact point or a wiring electrically connected to the contact point and the electrode in a state where the liquid is introduced into the internal space, This makes it possible to detect leakage of the plating liquid into the internal space. The substrate holder according to any one of claims 1 to 8, wherein, The substrate holder is a substrate holder for a horizontal plating module that holds the substrate in a horizontal orientation, or a vertical plating module that holds the substrate in a vertical orientation. Substrate holder. A plating device, which has: The substrate holder according to any one of claims 1 to 8; a liquid supply module that supplies liquid to the internal space of the substrate holder; and The plating module brings the substrate held by the substrate holder into contact with a plating liquid to plate the substrate. The plating device according to claim 15, wherein, The liquid supply module has a cleaning nozzle that cleans the internal space of the substrate holder and replaces the liquid in the internal space. The plating device according to claim 15, wherein, The plating device further includes a pre-wetting module for pre-wetting the substrate, The plating module holds the substrate in a wet state on the substrate holder. A method for plating a substrate, comprising: A substrate holder is prepared including a protective electrode having a material biased toward a high potential side with respect to a contact point for contacting and supplying power to a seed layer formed on the surface of the substrate, or having a ratio of The seed layer of the substrate has a low natural potential, and the protective electrode is electrically connected to the seed layer directly or via a conductor; A liquid is introduced into an internal space of the substrate holder that houses the outer peripheral portion of the substrate in a sealed state from the outside, and in the internal space, at least a part of the protective electrode and the The contact portion of the substrate holder contacting the seed layer of the substrate is covered; and The substrate held in the substrate holder is plated in a state where the liquid is introduced into the internal space of the substrate holder.

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