JP7683473B2 - Metal film deposition equipment - Google Patents

Description

The present invention relates to a film forming device that forms a metal film on the surface of a substrate.

Conventionally, metal coatings have been formed by depositing metal on the surface of a substrate (for example, see Patent Document 1). Patent Document 1 describes a metal coating forming device that includes an anode, a solid electrolyte membrane disposed between the anode and the substrate serving as the cathode, a power supply unit that applies a voltage between the anode and the substrate, and a liquid storage unit that stores an electrolyte solution containing metal ions between the anode and the solid electrolyte membrane.

In this film forming device, a voltage is applied between the anode and the substrate using a power supply unit while the solid electrolyte membrane is in contact with the substrate. This causes the metal ions contained in the solid electrolyte membrane to migrate to the surface of the substrate in contact with the solid electrolyte membrane and are reduced on the surface of the substrate, causing the metal to precipitate on the surface of the substrate. This causes a metal coating made of the precipitated metal to be formed on the surface of the substrate.

JP 2016-169399 A

When forming a metal film using the above-mentioned film forming apparatus, it is common to add an additive to the electrolyte in order to improve the quality of the film. However, this additive is consumed when the metal film is formed on the substrate, and so if the metal film is continuously formed, the amount of additive contained in the electrolyte decreases. Thus, if film formation is performed with a reduced amount of additive, there is a risk of a decrease in the quality of the film.

The present invention was made in consideration of these points, and its purpose is to provide a metal film deposition device that improves the quality of the deposition by replenishing an additive to the electrolyte.

In consideration of the above-mentioned problems, the metal coating forming apparatus according to the present invention comprises an anode, a solid electrolyte membrane disposed between the anode and a substrate, a power supply unit that applies a voltage between the anode and the substrate using the substrate as a cathode, a container that contains the anode and an electrolyte solution containing metal ions, and has an opening on the substrate side covered with the solid electrolyte membrane, and a liquid tank that is connected to the container and supplies the electrolyte solution to the container. In this case, a voltage is applied between the anode and the substrate with the solid electrolyte membrane in contact with the substrate, thereby reducing the metal ions contained inside the solid electrolyte membrane, thereby forming a metal coating derived from the metal ions. The film forming apparatus for forming a metal film on the surface of the substrate includes an additive replenishing device that replenishing the additive to the electrolyte contained in the liquid tank, and a control device that controls the replenishing of the additive by the additive replenishing device. The control device calculates an integrated current value by integrating the current value passed from the anode to the substrate over time by applying a voltage from the power supply unit, estimates the consumption of the additive based on the integrated current value, and controls the additive replenishing device so that the additive according to the estimated consumption is replenished to the electrolyte.

In the above-mentioned film forming apparatus, when a metal film is formed on the surface of a substrate, additives are consumed together with metal ions. In this respect, according to the film forming apparatus of the present invention, the control device calculates an integrated current value by integrating the current value passed from the anode to the substrate over time. The integrated current value is the sum of the current value passed from the anode to the substrate multiplied by the current passing time at that current value. As the metal film is formed on the surface of the substrate, the integrated current value increases, and the consumption of additives increases together with the metal ions contained in the electrolyte. In this way, there is a correlation between the integrated current value and the consumption of additives. For this reason, the control device can estimate the consumption of additives used in forming the metal film from the integrated current value based on the correlation obtained in advance, for example, by experiments. The control device can determine the consumption of the additive as the amount of additive to be replenished to the electrolyte. The control device controls the additive replenishing device to replenish the electrolyte with an amount of additive corresponding to the estimated consumption. This makes it possible to avoid forming a metal film when the amount of additive is reduced, improving the quality of the film.

In a preferred embodiment, the film forming apparatus includes a recovery mechanism that recovers the electrolyte contained in the container into the liquid tank by replacing the electrolyte with air. The control device controls the recovery mechanism so that the electrolyte is recovered into the liquid tank after the metal film is formed. The control device controls the additive replenishing device so that the additive is replenished to the electrolyte in the liquid tank after the electrolyte is recovered.

According to this aspect, the additive can be replenished to the electrolyte in the liquid tank while all of the electrolyte contained in the container is returned to the liquid tank. Therefore, compared to when the additive is replenished to the electrolyte contained in the container, the replenished additive before being uniformly dispersed in the electrolyte does not adhere to the solid electrolyte film. Therefore, the replenished additive can be uniformly mixed into the electrolyte in the liquid tank. In particular, by stirring the electrolyte together with the replenished additive in the liquid tank, the additive can be uniformly dispersed in the electrolyte. Therefore, unevenness in the concentration of the additive can be suppressed, and the film formation quality can be improved.

In a preferred embodiment, the film forming apparatus includes an additive concentration measuring device that measures the concentration of the additive contained in the electrolyte. The control device determines whether the solid electrolyte membrane has been replaced after recovery of the electrolyte. If the control device determines that the solid electrolyte membrane has been replaced, it estimates the amount of additive consumed based on the concentration of the additive measured by the additive concentration measuring device. If the control device determines that the solid electrolyte membrane has not been replaced, it estimates the amount of additive consumed based on the integrated current value. The control device controls the additive replenishing device so that the additive according to the estimated amount of consumption is replenished to the electrolyte.

According to the inventors' experiments, additives are easily attached to the solid electrolyte membrane, and when the membrane is replaced, additives in the electrolyte are easily carried away from the membrane forming device. Therefore, due to the carry-out of additives when replacing the solid electrolyte membrane, the actual consumption of additives tends to be greater than the consumption of additives estimated based on the integrated current value. In this embodiment, assuming such a case, when it is determined that the solid electrolyte membrane has been replaced, the consumption of additives can be accurately estimated based on the measured concentration of additives, so that a more appropriate amount of additive can be replenished to the electrolyte. In addition, since the concentration of additives in the liquid tank can be measured using the replacement time of the solid electrolyte membrane, it is not necessary to secure a new measurement time. On the other hand, when the membrane has not been replaced, the consumption of additives can be estimated based on the integrated current value, so that the consumption of additives can be quickly estimated. Therefore, an appropriate amount of additive can be efficiently replenished to the electrolyte.

In a preferred embodiment, the metal ions are copper ions, the electrolyte is a copper sulfate aqueous solution containing chloride ions in addition to the additive, and the additive is a brightener. The film forming apparatus includes a chloride ion concentration measuring device that measures the concentration of the chloride ions contained in the electrolyte, and a chloride ion supplying device that supplies the chloride ions to the electrolyte contained in the liquid tank. The control device estimates the consumption of the chloride ions based on the concentration of the chloride ions measured by the chloride ion concentration measuring device. The control device controls the chloride ion supplying device so that the chloride ions corresponding to the estimated consumption are supplied to the electrolyte.

Here, the chloride ions contained in the electrolyte aid the function of the brightener (the function of suppressing crystal growth by adsorbing to the growth points of crystal nuclei) and are effective in forming a stable and dense copper film. These chloride ions are contained in the electrolyte in small amounts compared to other additives. Thus, since the content of chloride ions in the electrolyte is small, the chloride ions may not be consumed in proportion to the integrated current value. In addition, the chloride ions may decrease due to adhesion to components of the film forming device. For this reason, it is difficult to estimate the amount of chloride ion consumption from the integrated current value. In this respect, according to the present embodiment, the concentration of chloride ions contained in the electrolyte is measured, and the amount of chloride ion consumption can be accurately estimated based on the measured chloride ion concentration, so that an appropriate amount of chloride ions can be replenished to the electrolyte.

In a preferred embodiment, the electrolyte contains at least two types of additives. The film forming apparatus has the additive supply devices in a number corresponding to the types of additives. The control device estimates the consumption amount of each of the additives based on the integrated current value. The control device controls each of the additive supply devices so that the additives corresponding to the estimated consumption amount are respectively supplied to the electrolyte.

In this way, the control device can independently estimate the consumption of each additive depending on the type of additive. The control device can replenish the electrolyte with an appropriate amount of each additive depending on the consumption of each additive. Therefore, even if the electrolyte contains multiple additives, it is possible to avoid forming a metal film when the amount of additive is reduced, thereby improving the quality of the film formation.

In a preferred embodiment, the anode is soluble in the electrolyte. According to this embodiment, the anode dissolves in the electrolyte, so that even if metal ions are consumed in the course of forming the metal film, the metal ions are replenished by dissolving the anode. Therefore, the additive is consumed while stabilizing the concentration of the metal ions contained in the electrolyte, so that the amount of additive replenished to the electrolyte can be more accurately controlled.

According to the present invention, the quality of the film formed can be improved by replenishing the electrolyte with additives.

1 is a schematic cross-sectional view of a metal film forming apparatus according to a first embodiment of the present invention. 2 shows a state in which an electrolyte solution has been injected into the film forming apparatus of FIG. 1. 2 is a flowchart illustrating control of the film forming apparatus of FIG. 1 . 4 is a graph illustrating an example of a step of replenishing an additive based on an integrated current value in the flowchart of FIG. 3 . FIG. 5 is a schematic cross-sectional view of a metal film forming apparatus according to a second embodiment of the present invention. 6 is a flowchart illustrating control of the film forming apparatus of FIG. 5 . FIG. 11 is a schematic cross-sectional view of a metal film forming apparatus according to a third embodiment of the present invention. 8 is a flowchart illustrating control of the film forming apparatus of FIG. 7 . FIG. 2 is a schematic diagram illustrating a peel test in an example of the present invention.

The following describes a metal film deposition device according to an embodiment of the present invention with reference to the drawings.

First Embodiment
Fig. 1 is a schematic cross-sectional view of a metal film forming apparatus 1A according to a first embodiment of the present invention. Fig. 2 shows a state in which an electrolytic solution L is injected into the film forming apparatus 1A of Fig. 1. Fig. 3 is a flow chart for explaining the control of the film forming apparatus 1A of Fig. 1. Fig. 4 is a graph for explaining an example of a step of replenishing an additive based on an integrated current value in the flow chart of Fig. 3.

As shown in Figures 1 and 2, the film forming device 1A includes an anode 11, a solid electrolyte membrane 13 disposed between the anode 11 and the substrate B, a power supply unit 14 that applies a voltage between the anode 11 and the substrate B with the substrate B serving as a cathode, and a container 15 that contains the anode 11 and an electrolyte solution L containing metal ions and has an opening 15a covered with the solid electrolyte membrane 13.

As shown in FIG. 2, the film forming apparatus 1A is an apparatus that applies a voltage between the anode 11 and the substrate B while the solid electrolyte membrane 13 is in contact with the substrate B, thereby reducing the metal ions contained inside the solid electrolyte membrane 13, and forming a metal film F derived from the metal ions on the surface B1 of the substrate B. In this embodiment, for convenience of explanation, the positional relationship of the components of the film forming apparatus 1A is specified on the assumption that the solid electrolyte membrane 13 is placed below the anode 11, and the substrate B is further placed below that. However, as long as the metal film F can be formed on the surface B1 of the substrate B, this positional relationship is not limited, and for example, the film forming apparatus 1A in FIG. 1 may be upside down.

The substrate B may be any material that functions as a cathode (i.e., a surface having electrical conductivity). The substrate B may be made of a metal material such as aluminum or iron, or may be made of a resin, ceramic, or the like, with a metal layer such as copper coated on the surface. The substrate B is electrically connected to the negative electrode of the power supply unit 14. The base 20 holds the substrate B below the container 15.

The anode 11 has a shape corresponding to the film formation region of the substrate B. The film formation region of the substrate B means the portion of the surface B1 of the substrate B facing the anode 11. The anode 11 is a non-porous (for example, non-porous) anode made of the same metal as the metal coating F, and is a block-shaped or flat anode. Examples of materials for the anode 11 include copper, nickel, gold, silver, platinum, and iridium dioxide. In this embodiment, the anode 11 is soluble in the electrolyte L. That is, the anode 11 is dissolved by applying a voltage using the power supply unit 14. However, if the film is formed using only the electrolyte L containing metal ions, the anode 11 does not need to be dissolved. The anode 11 is electrically connected to the positive electrode of the power supply unit 14.

The electrolyte L is a liquid that contains the metal of the metal film F to be formed in an ionic state, and examples of such metals include copper, nickel, gold, and silver. The electrolyte L is an aqueous solution in which these metals are dissolved (ionized) with an acid such as nitric acid, phosphoric acid, succinic acid, nickel sulfate, or pyrophosphoric acid. For example, when the metal is copper, examples of the electrolyte L include an aqueous solution containing copper sulfate, copper pyrophosphate, and the like.

The electrolyte L further contains an additive. The electrolyte L may contain at least two kinds of additives. The types of additives include an inhibitor, an accelerator, and a leveling agent. The inhibitor acts, for example, as a resistance to plating deposition and has the function of alleviating local current concentration. The accelerator (brightener) adsorbs to the growth point of the crystal nucleus and suppresses crystal growth. As a result, countless new nuclei are generated on the surface of the metal film, the metal film becomes fine crystals and dense, and a glossy film is obtained. In addition, the brightener acts to form the metal film F with a certain particle size, improving the adhesion between the metal film F and the substrate B. The leveling agent (leveler) preferentially adsorbs to the high current portion and has the effect of suppressing the electrodeposition reaction there. As a result, the metal film F is preferentially formed on the hole portion (recess), which is the low current portion, and it is possible to smooth the metal film F. The additive is added in an appropriate amount to the electrolyte L, and it is necessary to appropriately manage the amount of consumption.

The solid electrolyte membrane 13 is a flexible membrane that can be impregnated (contained) with metal ions by contacting it with the above-mentioned electrolyte solution L. The solid electrolyte membrane 13 is not particularly limited as long as the metal ions can pass through to the substrate B side when a voltage is applied by the power supply unit 14. Examples of the material of the solid electrolyte membrane 13 include fluorine-based resins such as Nafion (registered trademark) manufactured by DuPont, hydrocarbon-based resins, polyamic acid resins, and resins with ion exchange functions such as Selemion (CMV, CMD, CMF series) manufactured by Asahi Glass Co., Ltd. As shown in Figures 1 and 2, the solid electrolyte membrane 13 has an opposing surface 13a that faces the surface B1 of the substrate B when attached to the container 15.

1, the anode 11 and the solid electrolyte membrane 13 are attached to the container 15, and the inner wall surface of the container 15, the anode 11, and the solid electrolyte membrane 13 form a container space 15d for containing the electrolyte solution L. The container 15 has an opening 15a that opens to the side of the substrate B. The opening 15a opens downward, and the solid electrolyte membrane 13 is attached to the container 15 so as to cover the opening 15a. The anode 11 and the solid electrolyte membrane 13 are arranged at a distance from each other, and the container space 15d between them is filled with the electrolyte solution L. As shown in FIG. 2, the container 15 is structured so that the electrolyte solution L contained in the container space 15d directly contacts the anode 11 and the solid electrolyte membrane 13. The container 15 is made of a material that is insoluble in the electrolyte solution L.

Furthermore, the container 15 is formed with a supply flow path 15b for supplying the electrolytic solution L to the storage space 15d, and a discharge flow path 15c for discharging the electrolytic solution L from the storage space 15d. The supply flow path 15b is fluidly connected to a liquid supply pipe 50 described later, and the discharge flow path 15c is fluidly connected to a liquid discharge pipe 52 described later. The film forming apparatus 1A may have an agitator (not shown) in the liquid tank T, and the electrolytic solution L agitated by this agitator may be supplied to the storage space 15d via the liquid supply pipe 50 and the supply flow path 15b.

The linear actuator 70 of the film forming apparatus 1A raises and lowers at least one of the container 15 and the base 20 so that the solid electrolyte membrane 13 and the substrate B can be brought into contact with and separated from each other. In the present embodiment, as an example, the base 20 is fixed, and the container 15 is raised and lowered by the linear actuator 70. The linear actuator 70 is an electric actuator, and includes, for example, a guide 71 to which a motor (not shown) is attached, and a rod 72 that moves linearly relative to the guide 71. The rod 72 converts the rotational motion of the motor into linear motion, for example, by a ball screw or the like (not shown). The linear actuator 70 raises and lowers the container 15 relative to the base 20, making it possible to bring the solid electrolyte membrane 13 into contact with and separate from the substrate B. The linear actuator 70 may be provided at the bottom of the base 20. In this case, the substrate B is raised and lowered, making it possible to bring the solid electrolyte membrane 13 into contact with and separate from the substrate B.

Next, we will explain the mechanism for circulating the electrolyte L in the film forming device 1A.

As shown in FIG. 1, the liquid tank T of the film forming apparatus 1A contains an electrolyte L. The liquid tank T is connected to a container 15 via a pump P. Specifically, the electrolyte L in the liquid tank T is sucked by the pump P and supplied to the container 15 via a liquid supply pipe 50. The electrolyte L used during film formation is discharged from the container 15 to the liquid tank T via a liquid discharge pipe 52.

The liquid supply pipe 50 is provided with a three-way valve 60 that switches the flow direction of the electrolyte L. Specifically, the three-way valve 60 switches the flow direction of the electrolyte L from the liquid tank T to the container 15 through the liquid supply pipe 50, and the flow direction of the electrolyte L from the container 15 to the liquid tank T through the liquid return pipe 56 described later. In addition, by closing the three-way valve 60, the flow of the electrolyte L through the liquid supply pipe 50 and the flow of the electrolyte L through the liquid return pipe 56 can be stopped. The liquid supply pipe 50 is provided with a pump P that supplies the electrolyte L from the liquid tank T to the container 15. By rotating the pump P in the forward direction, the electrolyte L is sucked from the liquid tank T into the liquid supply pipe 50. The electrolyte L is pressure-fed to the container space 15d of the container 15 through the three-way valve 60. The pump P is structured to be capable of rotating in the forward direction and the reverse direction. When the pump P rotates in the forward direction, the electrolyte L is supplied from the liquid tank T to the container 15 as described above. On the other hand, when the pump P rotates in the reverse direction, the electrolyte L is collected from the container 15 to the liquid tank T through the liquid return pipe 56.

A pressure regulating valve 58 is interposed in the liquid discharge pipe 52, which prevents the pressure (liquid pressure) of the electrolyte L contained in the storage space 15d from exceeding a predetermined pressure. In addition, the pressure regulating valve 58 can seal the inside of the storage space 15d by closing the three-way valve 60, and as a result, the liquid pressure of the electrolyte L in the storage space 15d can be maintained at or below a predetermined pressure. In addition, a relief valve 62 is interposed in the liquid discharge pipe 52 between the storage body 15 and the pressure regulating valve 58. The relief valve 62 is opened, for example, when the inside of the liquid discharge pipe 52 becomes negative pressure (pressure lower than atmospheric pressure), and introduces the outside atmosphere into the storage space 15d of the storage body 15.

The film forming apparatus 1A also includes a recovery mechanism 80 that recovers the electrolyte solution L contained in the container 15 to the liquid tank T by replacing the electrolyte solution L contained in the container 15 with the atmosphere. The recovery mechanism 80 returns the electrolyte solution L from the container 15 to the liquid tank T through the liquid return pipe 56. In this embodiment, the liquid return pipe 56 shares a portion with a portion of the liquid supply pipe 50. Note that the liquid return pipe 56 may be a pipe separate from the liquid supply pipe 50.

The recovery mechanism 80 may include a pump P, a three-way valve 60, and a relief valve 62. In this embodiment, a case where the pump P is a component of the recovery mechanism 80 will be described. When the three-way valve 60 is switched so that the electrolyte L flows from the container 15 to the liquid tank T, the electrolyte L flows from the container 15 to the liquid tank T through the liquid return pipe 56 by rotating the pump P in reverse. In other words, the electrolyte L is sucked from the container 15 into the liquid return pipe 56 by rotating the pump P in reverse, and the electrolyte L is pumped to the liquid tank T. When the pump P continues to rotate in reverse, the relief valve 62 is opened, and the atmosphere is introduced into the storage space 15d of the container 15. In this way, the recovery mechanism 80 replaces the electrolyte L contained in the storage space 15d with the atmosphere by rotating the pump P in reverse, switching the three-way valve 60, and opening the relief valve 62. Note that in this embodiment, an example of the recovery mechanism 80 has been described. For example, the recovery mechanism 80 may recover the electrolyte L contained in the storage space 15d into the liquid tank T by pumping compressed air from the supply flow path 15b of the storage body 15. In this case, the replacement of the electrolyte L with the atmosphere is completed by leaving the compressed air in the storage space 15d.

Next, we will explain the mechanism for replenishing additives to the electrolyte L.

As shown in FIG. 1 and FIG. 2, the film forming apparatus 1A includes an additive supply device 30 and a control device 90. The additive supply device 30 supplies additives to the electrolyte L contained in the liquid tank T through an additive supply pipe 32. For example, the additive supply device 30 may include an additive tank (not shown) that contains the additives, and an additive pump (not shown) that pressure-feeds the additives contained in the additive tank to the liquid tank T. When the electrolyte L contains two or more types of additives, the film forming apparatus 1A has the additive supply devices 30 and the additive supply pipes 32 in the number corresponding to the types of additives. As an example, FIG. 1 and FIG. 2 show a case where two additive supply devices 30 and two additive supply pipes 32 are provided.

The control device 90 comprehensively controls the operation of the film forming apparatus 1A. One of the functions of the control device 90 is to control the replenishment of additives by the additive replenishment device 30. The control device 90 receives the current value measured by the ammeter A. The control device 90 constantly receives the above-mentioned current value while the film forming apparatus 1A is operating. The ammeter A measures the current value passed from the anode 11 to the substrate B by applying a voltage from the power supply unit 14. The control device 90 can transmit and receive information to and from each component of the film forming apparatus 1A via wired or wireless communication.

The control of the film forming apparatus 1A by the control device 90 will be described with reference to Figures 1 to 4. As shown in Figure 3, the control device 90 controls a transport device (not shown) and the like, thereby placing the substrate B on the base 20 (S100). Next, the control device 90 extends the rod 72 of the linear actuator 70 by a predetermined stroke amount. As a result, as shown in Figure 2, the rod 72 moves downward relative to the guide 71, the container 15 descends, and the opposing surface 13a of the solid electrolyte membrane 13 comes into contact with the surface B1 of the substrate B (S110).

Next, the control device 90 switches the three-way valve 60 so that the electrolyte L flows from the liquid tank T to the container 15 through the liquid supply pipe 50 (S120). Next, the control device 90 rotates the pump P in the forward direction (S130). This causes the electrolyte L to be supplied to the container 15 via the liquid supply pipe 50 and the three-way valve 60. The control device 90 drives the pump P in the forward direction until the electrolyte L in the container space 15d reaches a predetermined liquid pressure.

When the electrolyte L in the storage space 15d reaches a predetermined liquid pressure, the control device 90 stops driving the pump P (S140). This stops the supply of electrolyte L from the liquid tank T to the storage body 15. Next, the control device 90 closes the three-way valve 60 (S150). As a result, the storage body 15 is sealed, and the liquid pressure of the electrolyte L is maintained at or below the predetermined pressure.

In this manner, while the substrate B is pressed by the solid electrolyte membrane 13 due to the liquid pressure of the electrolyte L, the control device 90 controls the power supply unit 14 to apply a voltage between the anode 11 and the substrate B for a fixed time (S160). As a result, the metal ions contained in the solid electrolyte membrane 13 move to the substrate B and are reduced on its surface B1. As a result, the metal is precipitated on the surface B1 of the substrate B, and a metal coating F of a fixed thickness is formed on the surface B1 of the substrate B.

The control device 90 calculates the integrated current value (S170). The integrated current value (Ah) is the current value (A) received from the ammeter A integrated over time. More specifically, the integrated current value (Ah) is the sum of the current value (A) multiplied by the current flow time (h) at that current value. Here, the integrated current value being zero means the initial state in which the electrolyte L to which a predetermined additive has been added is introduced into the film forming device 1, or the state in which the additive has been supplied to the electrolyte L and the integrated current value has been reset. Starting from this state (a state in which no voltage is applied), the control device 90 calculates the integrated current value according to the current flow time from the anode 11 to the substrate B. The integrated current value is not reset until it reaches a predetermined threshold value S, and when it reaches the predetermined threshold value S (in this case, the additive is replenished to the electrolyte L as described later), the integrated current value is reset to zero (see FIG. 4). Thereafter, the control device 90 calculates the integrated current value again. The threshold value S is calculated in advance through experiments, etc., based on the correlation between the integrated current value and the amount of additive consumed (the amount of additive consumed increases as the integrated current value increases). For example, when the integrated current value is equal to or greater than the threshold value S, it is determined that there is a shortage of additive required for forming the metal coating F. The threshold value S is calculated so that there is no shortage of additive required for forming the metal coating F.

Next, the control device 90 recovers the electrolyte L from the container 15 by controlling the recovery mechanism 80 (S180, S190). Specifically, the control device 90 switches the three-way valve 60 so that the electrolyte L flows from the container 15 to the liquid tank T through the liquid return pipe 56 (S180). Next, the control device 90 rotates the pump P in reverse for a predetermined time until the recovery of the electrolyte L from the container 15 to the liquid tank T is completed (S190). At this time, the relief valve 62 is opened, and the atmosphere is introduced into the container space 15d of the container 15.

Next, the control device 90 judges whether the integrated current value is equal to or greater than a predetermined threshold value S (FIG. 4) (S200). If it is judged that the integrated current value is equal to or greater than the threshold value S (YES in S200), the control device 90 estimates the amount of additive consumed for film formation based on the integrated current value (S210). Next, the control device 90 judges the amount of additive consumed as the amount of additive to be replenished to the electrolyte L, and performs additive replenishment (S220). Specifically, the control device 90 controls the additive replenishment device 30 so that the additive according to the estimated consumption amount is replenished to the electrolyte L in the liquid tank T. Thereafter, the control device 90 resets the integrated current value to zero (FIG. 4). On the other hand, if it is judged that the integrated current value is smaller than the threshold value S (NO in S200), the control device 90 does not replenish the additive, and the control proceeds to S230 described later.

In this embodiment, the additive is supplied when it is determined that the integrated current value is equal to or greater than the threshold value S. However, for example, a threshold value may not be used (S200 may be omitted) and the amount of additive consumed may be estimated from the integrated current value (current value (A) multiplied by the time the current is applied) for each deposition of the metal coating F, and an amount of additive may be replenished according to this consumption.

Here, when the electrolyte L contains two or more kinds of additives, the control device 90 estimates the consumption amount of each additive based on the integrated current value, and controls each of the additive replenishing devices 30 so that the additives according to the estimated consumption amount are replenished to the electrolyte L. Specifically, a predetermined threshold value S related to the integrated current value is calculated for each of the two or more kinds of additives. The control device 90 controls the additive replenishing device 30 to replenish the electrolyte L with the additive of the type whose integrated current value is equal to or greater than the threshold value S according to its consumption amount. That is, S200, S210, and S220 shown in FIG. 3 are performed for each additive. Note that even when the electrolyte L contains two or more kinds of additives, the step of S200 may be omitted. Therefore, the control device 90 can replenish the electrolyte L with an appropriate amount of each additive according to the consumption amount of each additive. Therefore, even when the electrolyte L contains multiple additives, it is possible to avoid the formation of the metal film F when the amount of the additive is reduced.

In this way, after the metal film F is formed (S160), the control device 90 controls the recovery mechanism 80 so that the electrolyte L is recovered in the liquid tank T (S180, S190), and after the electrolyte L is recovered, controls the additive replenishing device 30 so that the additive is replenished to the electrolyte L in the liquid tank T (S200 to S220). In this way, the additive can be replenished to the electrolyte L in the liquid tank T with all of the electrolyte L contained in the container 15 returned to the liquid tank T. Therefore, the replenished additive before being uniformly diffused in the electrolyte L does not adhere to the solid electrolyte film 13. Therefore, the replenished additive can be uniformly mixed with the electrolyte L in the liquid tank T. Therefore, unevenness in the concentration of the additive can be suppressed, and the film formation quality can be improved.

Next, the control device 90 separates the solid electrolyte membrane 13 from the substrate B by controlling the operation of the linear actuator 70 (S230). Finally, the control device 90 controls a transport device (not shown) and the like to remove the substrate B from the base 20 (S240). In this manner, a series of controls for the film forming apparatus 1A using the control device 90 ends, and the control returns to the start.

As described above, in the film forming apparatus 1A according to this embodiment, the control device 90 calculates an integrated current value by integrating the current value passed from the anode 11 to the substrate B over time. Therefore, the control device 90 can estimate the consumption of the additive used in forming the metal film F from the integrated current value based on a correlation obtained in advance, for example, by an experiment or the like (i.e., the relationship that the integrated current value increases as the metal film F is formed on the surface B1 of the substrate B, and the consumption of the additive increases together with the metal ions contained in the electrolyte L). The control device 90 can determine that the consumption of the additive is the amount of additive to be replenished to the electrolyte L. The control device 90 controls the additive replenishing device 30 to replenish the electrolyte L with an amount of additive according to the estimated consumption. Therefore, it is possible to avoid forming the metal film F when the amount of additive is reduced, thereby improving the quality of the film.

In addition, in the film forming apparatus 1A, if the anode 11 is soluble in the electrolyte L, the additive is consumed while stabilizing the concentration of the metal ions contained in the electrolyte L, so that the amount of additive replenished to the electrolyte L can be more accurately controlled.

Second Embodiment
Fig. 5 is a schematic cross-sectional view of a film-forming apparatus 1B for a metal film according to a second embodiment of the present invention. Fig. 6 is a flow chart for explaining the control of the film-forming apparatus 1B in Fig. 5. The film-forming apparatus 1B according to the second embodiment is different from the film-forming apparatus 1A according to the first embodiment in that an additive concentration measuring device 40 is provided. Hereinafter, components having the same or similar functions as the film-forming apparatus 1A according to the first embodiment are denoted by the same reference numerals as those of the film-forming apparatus 1A according to the first embodiment, and explanations thereof are omitted, and different parts are explained.

As shown in FIG. 5, the film forming apparatus 1B includes an additive concentration measuring device 40 that measures the concentration of additives contained in the electrolyte L. The additive concentration measuring device 40 acquires the electrolyte L from the liquid tank T through a sample acquisition tube 41, for example, using a pump (not shown). The additive concentration measuring device 40 may be, for example, a CVS (Cyclic Voltammetry Stripping) analyzer. The additive concentration measuring device 40 can individually measure the concentration of additives (inhibitors, accelerators, leveling agents, etc.) contained in the electrolyte L. The additive concentration measuring device 40 transmits the measured concentration of each additive to the control device 90.

Next, the control of the film forming apparatus 1B using the control device 90 will be described. As shown in FIG. 6, after the solid electrolyte membrane 13 is separated from the substrate B (S230), the control device 90 determines whether the solid electrolyte membrane 13 has been replaced (S400). That is, the control device 90 determines whether the solid electrolyte membrane 13 has been replaced after the electrolytic solution L is collected. The control device 90 may determine that the solid electrolyte membrane 13 should be replaced when the metal film F has been formed, for example, 10 times. The relationship between the number of times the film has been formed and the timing of replacing the solid electrolyte membrane 13 is an example and is not limited thereto. The control device 90 controls a membrane replacement device (not shown) to replace the solid electrolyte membrane 13.

When the control device 90 determines that the solid electrolyte membrane 13 has been replaced (YES in S400), the control device 90 determines whether the concentration of the additive measured by the additive concentration measuring device 40 is equal to or lower than a predetermined additive concentration threshold (S430). The additive concentration is the ratio of the additive to the electrolyte L. Here, as the metal film is formed on the surface B1 of the substrate B, the consumption of the additive increases together with the metal ions contained in the electrolyte L. Therefore, as the consumption of the additive increases, the concentration of the additive in the electrolyte L obtained by the additive concentration measuring device 40 decreases. In this way, there is a correlation between the consumption of the additive and the concentration of the additive. In addition, the additive concentration threshold may be calculated in advance, for example, by an experiment, based on the above correlation between the consumption of the additive and the concentration of the additive (the relationship in which the concentration of the additive decreases as the consumption of the additive increases). When the concentration of the additive in the electrolyte L (the concentration of each additive in the case of multiple additives) becomes equal to or lower than this additive concentration threshold, it is determined that the additive required for forming the metal film F is insufficient. This additive concentration threshold was calculated so that there would be no shortage of additives required for forming the metal coating F.

When the control device 90 determines that the concentration of the additive in the electrolyte L is equal to or lower than the additive concentration threshold (YES in S430), it estimates the consumption of the additive based on the concentration of the additive measured by the additive concentration measuring device 40 (S440). Specifically, the control device 90 can estimate the consumption of the additive used in forming the metal coating F from the concentration of the additive based on the correlation (the relationship in which the concentration of the additive decreases as the consumption of the additive increases) previously determined, for example, through an experiment or the like.

Next, the control device 90 determines that the estimated consumption amount of the additive is the amount of additive to be replenished to the electrolyte L, and carries out the replenishment of the additive (S450). Specifically, the control device 90 controls the additive replenishment device 30 so that the additive according to the estimated consumption amount is replenished to the electrolyte L. Then, the control proceeds to S240.

On the other hand, if it is determined that the concentration of the additive in the electrolyte L is not equal to or less than the additive concentration threshold (NO in S430), the control device 90 does not replenish the additive, and the control proceeds to S240. In this embodiment, if it is determined that the solid electrolyte membrane 13 has been replaced (YES in S400), the additive concentration threshold is not used (S430 is omitted), and the additive consumption amount may be estimated based on the additive concentration each time the solid electrolyte membrane 13 is replaced (S440), and the additive replenishing device 30 may replenish the additive based on the estimated consumption amount (S450).

When the control device 90 determines that the solid electrolyte membrane 13 has not been replaced (NO in S400), it estimates the amount of additive consumed based on the integrated current value, and controls the additive supply device 30 so that the additive corresponding to the estimated amount of consumption is replenished to the electrolyte solution L (S200, S210, S220).

As described above, in the film forming apparatus 1B according to this embodiment, when it is determined that the solid electrolyte membrane 13 has been replaced, the additive consumption amount is estimated based on the measured additive concentration, so that even if the additive is taken out of the film forming apparatus 1B during replacement, an appropriate amount of additive can be replenished to the electrolyte L. On the other hand, if the membrane has not been replaced, the additive consumption amount is estimated based on the integrated current value, so that the additive consumption amount can be quickly estimated. Therefore, an appropriate amount of additive can be efficiently replenished to the electrolyte.

<Modification>
The film forming apparatus according to the modified example differs from the film forming apparatus 1B according to the second embodiment in that a copper ion concentration measuring device, a copper ion supplying device, a sulfate ion concentration measuring device, and a sulfate ion concentration adjusting device (none of which are shown) are provided. Hereinafter, the film forming apparatus according to this modified example will be described with the same reference numerals as those of the film forming apparatus 1B according to the second embodiment.

In the film forming apparatus according to the modified example, the anode 11 is insoluble in the electrolytic solution L, the metal ions are copper ions, and the electrolytic solution L is a copper sulfate aqueous solution containing sulfate ions. The film forming apparatus according to the modified example includes a copper ion concentration measuring device that measures the concentration of copper ions contained in the electrolytic solution L, and a sulfate ion concentration measuring device that measures the concentration of sulfate ions contained in the electrolytic solution L. The film forming apparatus also includes a copper ion replenishing device that replenishing copper ions to the electrolytic solution L contained in the liquid tank T, and a sulfate ion concentration adjusting device that adjusts the concentration of sulfate ions in the electrolytic solution L contained in the liquid tank T. The copper ion concentration measuring device and the sulfate ion concentration measuring device acquire the electrolytic solution L from, for example, a sample acquisition tube 41. The copper ion concentration measuring device and the sulfate ion concentration measuring device respectively measure the concentration of copper ions and sulfate ions contained in the electrolytic solution L, and transmit the measured concentration of copper ions and sulfate ions to the control device 90.

In the film forming apparatus according to this modified example, the control device 90 controls the copper ion replenishing device and the sulfate ion concentration adjusting device before replenishing the additive to the electrolyte L using the additive replenishing device 30. Specifically, when the control device 90 determines that the solid electrolyte membrane 13 has been replaced (YES in S400 in FIG. 6), it estimates the consumption of copper ions based on the concentration of copper ions measured by the copper ion concentration measuring device. In addition, the control device 90 estimates, for example, the consumption (evaporation) of water based on the concentration of sulfate ions measured by the sulfate ion concentration measuring device. The control device 90 controls the copper ion replenishing device so that copper ions according to the estimated consumption are replenished to the electrolyte L. In addition, the control device 90 controls the sulfate ion concentration adjusting device so that water according to the estimated consumption is replenished to the electrolyte L. The sulfate ion concentration adjusting device replenishing water to the electrolyte L when the concentration of sulfate ions increases due to the evaporation of water components from, for example, a copper sulfate aqueous solution. On the other hand, the sulfate ion concentration adjusting device may replenish sulfate ions when the concentration of sulfate ions in the electrolyte L decreases. In this manner, in the film forming apparatus according to the modified example, after the adjustment of the copper ion concentration and sulfate ion concentration in the electrolytic solution L is completed, a process of replenishing the additive to the electrolytic solution L is carried out using the additive replenishing device 30 (S430 to S450 in FIG. 6).

As described above, in the film forming apparatus according to this modified example, after the adjustment of the copper ion concentration and sulfate ion concentration in the electrolyte L is completed, the additive is replenished to the electrolyte L using the additive replenishing device 30. Therefore, after the concentrations of copper ions and sulfate ions in the electrolyte L are appropriately adjusted, the additive is replenished to the electrolyte L. This allows a more accurate amount of additive to be replenished.

Third Embodiment
Fig. 7 is a schematic cross-sectional view of a metal film forming apparatus 1C according to a third embodiment of the present invention. Fig. 8 is a flow chart for explaining the control of the film forming apparatus 1C of Fig. 7. The film forming apparatus 1C according to the third embodiment is different from the film forming apparatus 1B according to the second embodiment in that a chloride ion concentration measuring device 42 is provided. Hereinafter, components having the same or similar functions as the film forming apparatuses 1A and 1B described above will be denoted by the same reference numerals as those of the film forming apparatuses 1A and 1B, and explanations thereof will be omitted, and different parts will be explained.

In the film forming apparatus 1C of this embodiment, the metal ions contained in the electrolytic solution L are copper ions, the electrolytic solution L is a solution containing chloride ions in an aqueous copper sulfate solution, and the additive is an accelerator (brightener). As shown in FIG. 7, the film forming apparatus 1C includes a chloride ion concentration measuring device 42 that measures the concentration of chloride ions contained in the electrolytic solution L, and a chloride ion supplying device 43 that supplies chloride ions to the electrolytic solution L contained in the liquid tank T.

The chloride ion concentration measuring device 42 acquires the electrolyte L from the sample acquisition tube 41 using, for example, a pump (not shown). The chloride ion concentration measuring device 42 measures the concentration of the chloride ions contained in trace amounts in the electrolyte L. The chloride ion concentration measuring device 42 transmits the measured chloride ion concentration to the control device 90.

The chloride ion supply device 43 supplies chloride ions to the electrolyte L in the liquid tank T via a chloride ion supply pipe 43a. For example, the chloride ion supply device 43 may include a chloride ion tank (not shown) that contains chloride ions, and a chloride ion pump (not shown) that supplies chloride ions from the chloride ion tank to the liquid tank T.

Next, the control of the film forming apparatus 1C using the control device 90 will be described. As shown in FIG. 8, when the control device 90 determines that the solid electrolyte membrane 13 has been replaced (YES in S400), it determines whether the concentration of chloride ions measured by the chloride ion concentration measuring device 42 is equal to or lower than a predetermined chloride ion concentration threshold (S500). The chloride ion concentration is the ratio of chloride ions to the electrolyte L. The chloride ions contained in the electrolyte L help the function of the brightener, so that the consumption of chloride ions increases as the consumption of the brightener contained in the electrolyte L increases. Therefore, as the consumption of chloride ions increases, the concentration of chloride ions in the electrolyte L obtained by the chloride ion concentration measuring device 42 decreases. In this way, there is a correlation between the consumption of chloride ions and the concentration of chloride ions. The chloride ion concentration threshold may be calculated in advance, for example, by experiments, based on the above correlation between the consumption of chloride ions and the concentration of chloride ions (the relationship in which the concentration of chloride ions decreases as the consumption of chloride ions increases). If the concentration of chloride ions in the electrolyte L falls below this chloride ion concentration threshold, it is determined that the effect of the accelerator (brightener) is not manifested. This chloride ion concentration threshold is calculated so that the effect of the brightener can continue to be manifested.

When the control device 90 determines that the concentration of chloride ions in the electrolyte L is equal to or lower than the chloride ion concentration threshold (YES in S500), it estimates the amount of chloride ions consumed based on the concentration of chloride ions measured by the chloride ion concentration measuring device 42 (S510). Specifically, the control device 90 can estimate the amount of chloride ions consumed in forming the metal coating F from the concentration of chloride ions based on the correlation (the relationship in which the concentration of chloride ions decreases as the consumption of chloride ions increases) previously determined, for example, through experiments.

Next, the control device 90 controls the chloride ion supply device 43 so that chloride ions according to the estimated consumption are supplied to the electrolyte L (S520). Next, this control proceeds to S430. In this manner, according to the film forming device 1C of this embodiment, the concentration of chloride ions contained in the electrolyte L is measured, so that the concentration of chloride ions contained in trace amounts in the electrolyte L can be accurately measured. The consumption of chloride ions is estimated based on this measured chloride ion concentration, so that the consumption of chloride ions can be accurately grasped. Therefore, an appropriate amount of chloride ions can be supplied to the electrolyte L.

On the other hand, when it is determined that the concentration of chloride ions in the electrolyte L is not equal to or less than the chloride ion concentration threshold (NO in S500), the control device 90 does not replenish chloride ions, and the control proceeds to S430. In this embodiment, when it is determined that the solid electrolyte membrane 13 has been replaced (YES in S400), the chloride ion concentration threshold is not used (S500 is omitted), and the amount of chloride ion consumption may be estimated based on the chloride ion concentration every time the solid electrolyte membrane 13 is replaced (S510), and chloride ions may be replenished by the chloride ion replenishing device 43 based on the estimated amount of consumption ( S520 ).

The present invention is illustrated by the following examples.

[Example 1]
A glass epoxy board (FR-4) was prepared as a substrate for forming a film on its surface, which was made by impregnating a layer of glass fiber cloth with epoxy resin. A copper foil was formed on the surface of this glass epoxy board.

Next, a copper film was formed using the film forming apparatus 1A (FIGS. 1 and 2) according to the first embodiment. A copper sulfate aqueous solution (Cu-BRITE-SED) manufactured by JCU Corporation was used as the electrolyte, and a Cu plate was used as the anode. The electrolyte temperature was set to 42° C., a solid electrolyte film (Nafion (manufactured by DuPont)) having a thickness of 8 μm was attached to the substrate, and the copper film was formed under the following conditions: electrolyte pressure of 0.6 MPa, current density of 7 A/dm ² , membrane area of 100 cm ² , and cumulative membrane formation time of 1162 seconds. In this Example 1, after the second membrane formation was completed, it was determined that the integrated current value exceeded a predetermined threshold value. Therefore, after the second membrane formation was completed and before the third membrane formation was started, the additive was replenished by the additive replenishing device according to the additive consumption amount estimated based on the integrated current value.

[Example 2]
A copper film was formed using the film forming apparatus 1B (FIG. 5) according to the second embodiment under the same film forming conditions as in Example 1. The difference from Example 1 is that the additive was replenished by the additive replenishing device according to the concentration of the additive measured by the additive concentration measuring device every time one film formation was completed.

[Example 3]
A copper film was formed using the film forming apparatus 1C (FIG. 7) according to the third embodiment under the same film forming conditions as in Example 2. The difference from Example 2 is that each time one film formation was completed, chloride ions were replenished by the chloride ion replenishment device in accordance with the concentration of chloride ions measured by the chloride ion concentration measuring device.

[Comparative Example 1]
A copper film was formed in the same manner as in Example 1. The difference from Example 1 is that the additive was not replenished by the additive replenishing device.

[Comparative Example 2]
A copper film was formed in the same manner as in Example 3. The difference from Example 3 is that chloride ions were not replenished by the chloride ion replenishing device.

<Checking the film formation state>
A sample piece of 10 mm x 50 mm was prepared for the substrate on which the film was formed as described above, and the adhesion of the copper film to the substrate was measured by a peel test (Shimadzu Corporation EZ test). FIG. 9 is a schematic diagram for explaining the peel test in the embodiment of the present invention. As shown in FIG. 9, the substrate B' of the sample piece was attached to a fixed plate X, and the copper film F' of the sample piece chucked by the device was peeled off in a 90° direction relative to the substrate B'. Specifically, the copper film F' was pulled in the direction of the arrow V while the fixed plate X was slid in the direction of the arrow H. The results are shown in Table 1 (Example 1, Example 2, Comparative Example 1) and Table 2 (Example 3, Comparative Example 2).

(Results and Discussion)
Here, when the adhesion strength of the copper film F' to the substrate B' of the sample piece is 0.5 kN/m or less, the adhesion strength is judged to be insufficient (bad), and when the adhesion strength is greater than 0.5 kN/m, the adhesion strength is judged to be good. The above 0.5 kN/m is a value generally used as a threshold value for the adhesion strength of a wiring board. As is clear from Table 1, in Examples 1 and 2, it was confirmed that the adhesion strength of the copper film F' to the substrate B' was good in all samples from the first film formation to the fifth film formation. In Example 1, it is considered that after the second film formation was completed and before the third film formation was started, the additive replenishing device replenished the additives, and an appropriate amount of additives (particularly brightener) was replenished to the electrolyte. In addition, in Example 2, it is considered that the additive replenishing device replenished the additives every time one film formation was completed, and an appropriate amount of additives (particularly brightener) was replenished to the electrolyte.

In Example 3, it was confirmed that the adhesion of the copper film F' to the substrate B' was good in all samples from the first coating to the 55th coating. In Example 3, the additive was replenished by the additive replenishing device every time a coating was completed, and the chloride ions that bring out the effect of the additive (brightener) were also replenished, so it is believed that the effect of the brightener continues to be exerted.

In contrast, in Comparative Example 1, the adhesion strength of the copper coating F' to the substrate B' of the sample piece fell below 0.5 kN/m from the third deposition, and the adhesion strength decreased as the number of depositions increased. This is thought to be because in Comparative Example 1, additives were not replenished to the electrolyte, and so additives were consumed along with metal ions when the metal coating was deposited on the surface of the substrate, resulting in a decrease in the concentration of additives (especially brightener) in the electrolyte.

In Comparative Example 2, it was confirmed that the adhesion strength of the copper coating F' to the substrate B' of the sample piece fell below 0.5 kN/m from the 51st film formation. In Comparative Example 2, the additive (brightener) was replenished by the additive replenishing device after each film formation, but chloride ions were not replenished, and it is believed that there was a shortage of chloride ions to exert the effect of the brightener. In other words, it is believed that the effect of the brightener was not exerted in Comparative Example 2, and therefore the results shown in the above table were obtained.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the film forming apparatuses 1A, 1B, and 1C according to the above-mentioned embodiments, but includes all aspects included in the concept of the present invention and the scope of the claims. In addition, each configuration may be appropriately and selectively combined to achieve the above-mentioned problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above-mentioned embodiments may be appropriately changed depending on the specific aspects of the present invention.

For example, in the above embodiment, a case has been described in which the power supply unit 14 applies a voltage between the anode 11 and the substrate B while the circulation of the electrolyte L is stopped by closing the three-way valve 60 (see S140 to S160 in FIG. 3). However, when the power supply unit 14 applies a voltage, the three-way valve 60 does not have to be closed. In this case, the liquid pressure of the electrolyte L can be maintained at a predetermined pressure by continuing the forward rotation of the pump P.

1A, 1B, 1C: Film forming device, 11: Anode, 13: Solid electrolyte membrane, 14: Power supply unit, 15: Container, 15a: Opening, 30: Additive supply device, 40: Additive concentration measuring device, 42: Chloride ion concentration measuring device, 43: Chloride ion supply device, 80: Recovery mechanism, 90: Control device, B: Substrate, B1: Surface, F: Metal coating, L: Electrolyte, T: Liquid tank

Claims (4)

An anode;
a solid electrolyte membrane disposed between the anode and a substrate;
a power supply unit that applies a voltage between the anode and the substrate, the substrate being a cathode;
a container that contains the anode and an electrolytic solution containing metal ions, and an opening that opens to the side of the base material is covered with the solid electrolyte membrane;
a liquid tank connected to the container and configured to supply the electrolyte to the container;
a voltage is applied between the anode and the substrate in a state in which the solid electrolyte membrane is in contact with the substrate, thereby reducing the metal ions contained inside the solid electrolyte membrane, thereby forming a metal coating derived from the metal ions on a surface of the substrate,
The electrolyte further comprises an additive,
The film forming apparatus includes:
an additive replenishing device that refills the additive into the electrolyte contained in the electrolyte tank;
a recovery mechanism that recovers the electrolyte contained in the container into the liquid tank by replacing the electrolyte contained in the container with air;
an additive concentration measuring device for measuring the concentration of the additive contained in the electrolyte;
A control device that controls the replenishment of the additive by the additive replenishment device,
The control device includes:
controlling the recovery mechanism so that the electrolytic solution is recovered in the liquid tank after the metal coating is formed;
After the electrolyte is collected, the additive supply device is controlled so that the additive is replenished to the electrolyte in the liquid tank;
The control device includes:
Calculating an integrated current value by integrating a current value passed from the anode to the substrate over time due to application of a voltage by the power supply unit;
After recovering the electrolyte solution, it is determined whether the solid electrolyte membrane has been replaced;
When it is determined that the solid electrolyte membrane has been replaced, a consumption amount of the additive is estimated based on the concentration of the additive measured by the additive concentration measuring device;
When it is determined that the solid electrolyte membrane has not been replaced, a consumption amount of the additive is estimated based on the integrated current value;
a control unit for controlling the additive supply device so that the additive according to the estimated consumption amount is supplied to the electrolyte; the metal ion is a copper ion,
The electrolytic solution is a solution containing a copper sulfate aqueous solution and, in addition to the additive, chloride ions,
the additive is a brightener,
The film forming apparatus includes:
A chloride ion concentration measuring device for measuring the concentration of the chloride ions contained in the electrolyte;
a chloride ion supply device that supplies the chloride ions to the electrolyte contained in the liquid tank,
The control device includes:
estimating a consumption amount of the chloride ions based on the concentration of the chloride ions measured by the chloride ion concentration measuring device;
2. The metal film forming apparatus according to claim 1 , further comprising: a control unit for controlling the chloride ion supply device so that the chloride ions corresponding to the estimated consumption amount are supplied to the electrolyte. The electrolyte solution includes at least two additives,
the film forming apparatus includes the additive supply devices in a number corresponding to the types of the additives,
The control device includes:
estimating the consumption amount of each of the additives based on the integrated current value;
3. The metal film forming apparatus according to claim 1 , further comprising: controlling each of the additive replenishing devices so that the additives are replenished to the electrolyte in amounts corresponding to the estimated consumption amounts. 4. The metal film forming apparatus according to claim 1 , wherein the anode is soluble in the electrolyte.

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