Plating apparatus and plating method

Abstract

The object of the present invention is to supply metal ions while maintaining a constant composition of the plating solution during plating. a cation exchange membrane dividing the plating tank into an anode chamber for holding an anolyte and a cathode chamber for holding a cathode fluid; an anode disposed in the anode chamber; a replenishing device for replenishing the cathode fluid with the same metal as a metal deposited on the substrate, or a metal compound containing the metal; and a control device for controlling the replenishing device to replenishing the metal or the metal compound containing the replenishing amount of the metal, which is an amount obtained by subtracting the amount of metal ions of the metal that permeated from the anode chamber to the cathode chamber through the cation exchange membrane from the amount of the metal deposited on the substrate, from the amount of the metal deposited on the substrate by plating, from the replenishing device.

Description

[Technical field]

[0001] The present invention relates to a plating apparatus and a plating method. [Background technology]

[0002] A plating apparatus for plating a substrate (e.g., a semiconductor wafer) includes an anode chamber in which an anode is placed, and a cathode chamber in which a substrate as a cathode is placed. In general, in such plating apparatuses, a liquid having the same composition as a plating solution (cathode solution) is introduced into the anode chamber as an anode solution. When plating is performed using an insoluble anode, a metal (e.g., Cu) is precipitated at the cathode (substrate) in an amount corresponding to the amount of electrolysis, and Cu ions in the plating solution are consumed, while an acid is generated at the anode. Therefore, as described in Japanese Patent No. 6767243 (Patent Document 1), a metal oxide (e.g., CuO), a metal hydroxide, a metal carbonate, or the like is added and dissolved in the plating solution in an amount corresponding to the amount of electrolysis to replenish the metal ions and neutralize the acid. In general, an ion exchange membrane as described in Patent Document 2 is used as a diaphragm that divides the inside of a plating tank into an anode chamber and a cathode chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6767243 specification [Patent Document 2] Patent No. 7165843 specification Summary of the Invention [Problem to be solved by the invention]

[0004] When the anode chamber and the cathode chamber are separated by a cation exchange membrane, both hydrogen ions and metal ions (copper ions) pass through the cation exchange membrane, so after plating starts, the copper ions in the anolyte gradually move into the catholyte as the anolyte is electrolyzed. For this reason, if the amount of metal (Cu) deposited by plating is replenished to the catholyte, excessive metal ions will be added to the catholyte, causing the composition of the catholyte to shift. If the composition of the catholyte, which is the plating solution that comes into contact with the substrate, shifts, it can have a negative effect on the quality of the plating. In particular, the smaller the ratio of the amount of catholyte to the amount of anode liquid, the greater the impact (shift in the composition of the catholyte) is expected to be.

[0005] The present invention aims to solve at least some of the above problems. One of the objects of the present invention is to supply metal ions while maintaining a constant composition of the plating solution during plating. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a plating apparatus for plating a substrate, comprising: a plating tank; a cation exchange membrane dividing the plating tank into an anode chamber for holding an anolyte and a cathode chamber for holding a cathode liquid; an anode disposed in the anode chamber; a replenishing device for replenishing the cathode liquid with the same metal as the metal deposited on the substrate, or a metal compound containing the metal; and a control device for controlling the replenishing device to replenishing the metal or the metal compound containing the replenishing amount of the metal, which is an amount obtained by subtracting the amount of metal ions of the metal that permeated from the anode chamber to the cathode chamber through the cation exchange membrane from the amount of the metal deposited on the substrate, from the amount of the metal deposited on the substrate by plating, from the replenishing device.

[0007] According to one aspect of the present invention, there is provided a plating method for plating a substrate, comprising the steps of: supplying a replenishment amount of the metal, or a compound of the metal containing the replenishment amount of the metal, to a cathode solution, the replenishment amount being an amount obtained by subtracting an amount of metal ions of the metal that have permeated from the anode chamber to the cathode chamber through an ion exchange membrane that separates the anode chamber and the cathode chamber in a plating tank from the amount of metal deposited on the substrate. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view showing an overall configuration of a plating apparatus according to an embodiment; [Diagram 2] 1 is a plan view showing an overall configuration of a plating apparatus according to an embodiment; [Diagram 3] FIG. 2 is a schematic diagram of a plating module according to an embodiment. [Figure 4] FIG. 2 is an explanatory diagram illustrating a reaction of ions in a plating tank. [Figure 5A] 1 is a graph showing changes in copper and sulfuric acid concentrations in an anolyte. [Figure 5B] 1 is a graph showing a change in concentration of ions in an anolyte. [Figure 5C] 1 is a graph showing the change in transport number of ions passing through a membrane. [Figure 5D] 1 is a graph showing changes in copper and sulfuric acid concentrations in a cathode solution when CuO equivalent to the amount of plating deposition is replenished. [Figure 6A] FIG. 2 is an explanatory diagram for explaining a method for calculating a refill amount of CuO. [Figure 6B] FIG. 2 is an explanatory diagram for explaining a method for calculating a refill amount of CuO. [Figure 6C] FIG. 2 is an explanatory diagram for explaining a method for calculating a refill amount of CuO. [Figure 6D] FIG. 2 is an explanatory diagram for explaining a method for calculating a refill amount of CuO. [Figure 7A] An example of the configuration of a plating cell used in an experiment to estimate the ionic conductivity ratio α is shown. [Figure 7B]1 is a graph showing changes in Cu concentration in an anolyte according to an experiment and a simulation. [Figure 8A] 1 is a table showing an example of an estimation result of an acid dissociation equilibrium constant Ka′. [Figure 8B] 1 is a graph showing an example of an estimation result of an acid dissociation equilibrium constant Ka′. [Figure 9] The following shows an example of the numerical values ​​of the parameters used in the simulation to calculate the CuO supply amount. [Figure 10A] 13 is a graph showing a simulation result of the transport number of hydrogen ions. [Figure 10B] 1 is an enlarged graph showing the change in transport number of hydrogen ions immediately after bath preparation. [Figure 10C] 1 is a graph showing an enlarged view of the change in transport number of hydrogen ions after the composition of the anolyte has stabilized. [Figure 11] A simplified formula for calculating the amount of CuO to be replenished is shown below. [Figure 12A] 1 is a graph showing changes in transport number of hydrogen ions. [Figure 12B] 1 is an enlarged graph showing the change in transport number of hydrogen ions immediately after bath preparation. [Figure 12C] 1 is a graph showing an enlarged view of the change in transport number of hydrogen ions after the composition of the anolyte has been stabilized. [Figure 13A] This shows the change in ion concentration in the cathode solution when CuO equivalent to the amount of plating deposition was replenished. [Figure 13B] This shows the change in ion concentration in the cathode solution when CuO is replenished based on the curve of the hydrogen ion transport number tH obtained by simulation. [Figure 14A] The change in hydrogen ion transport number and the change in ion concentration in the catholyte are shown. [Figure 14B] The change in hydrogen ion transport number and the change in ion concentration in the catholyte are shown. [Figure 14C] The change in hydrogen ion transport number and the change in ion concentration in the catholyte are shown. [Figure 14D] The change in hydrogen ion transport number and the change in ion concentration in the catholyte are shown. [Figure 15A]This shows the change in hydrogen ion transport number in a plating solution with a constant Cu / H2SO4 ratio and different Cu concentrations. [Figure 15B] The change curves of hydrogen ion transport number are shown for different Cu / H2SO4 ratios at a constant Cu concentration. [Figure 16A] Correction curve: The formula that represents the approximate curve of the tH-q curve is shown below. [Figure 16B] 13 is a table showing an example of calculating a coefficient an. [Figure 16C] 13 is a graph showing an example of calculation of a coefficient an. [Figure 16D] The approximate formula for the coefficient an is shown below. [Figure 16E] 13 is a table showing an example of calculation of a coefficient ki. [Figure 17] The formula for calculating the CuO replenishment amount for any plating solution composition is shown below. [Figure 18A] 1 shows an approximation curve of a correction curve applicable to any plating solution composition, and a simulation result of adjusting an ion concentration in a cathode solution using the approximation curve. [Figure 18B] 1 shows an approximation curve of a correction curve applicable to any plating solution composition, and a simulation result of adjusting an ion concentration in a cathode solution using the approximation curve. [Figure 18C] 1 shows an approximation curve of a correction curve applicable to any plating solution composition, and a simulation result of adjusting an ion concentration in a cathode solution using the approximation curve. [Figure 18D] 1 shows an approximation curve of a correction curve applicable to any plating solution composition, and a simulation result of adjusting an ion concentration in a cathode solution using the approximation curve. [Figure 19A] FIG. 11 is an explanatory diagram for explaining a method for calculating the CuO replenishment amount when the ion concentration in the anolyte is directly monitored. [Figure 19B] An example of the configuration of a plating module for directly monitoring the ion concentration in the anolyte is shown. [Figure 20] The formula for calculating the amount of CuO to be replenished when the plating solutions (cathode solutions) of multiple plating tanks or cells are connected and the solutions are managed collectively is shown below. [Figure 21A]FIG. 2 is a schematic diagram of a plating module with an enlarged view of the vicinity of a diaphragm. [Figure 21B] FIG. 2 is an explanatory diagram illustrating the movement of ions by diffusion through a membrane. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a plating apparatus 1000 according to an embodiment of the present invention will be described with reference to the drawings. Note that the drawings are schematic illustrations to facilitate understanding of the characteristics of the object, and the dimensional ratios of the components are not necessarily the same as those of the actual objects.

[0010] First Embodiment Fig. 1 is a perspective view showing the overall configuration of a plating apparatus 1000 of this embodiment. Fig. 2 is a plan view showing the overall configuration of the plating apparatus 1000 of this embodiment. As shown in Figs. 1 and 2, the plating apparatus 1000 includes a load port 100, a transfer robot 110, an aligner 120, a pre-wet module 200, a pre-soak module 300, a plating module 400, a cleaning module 500, a spin rinse dryer 600, a transfer device 700, and a control module 800.

[0011] The load port 100 is a module for loading a wafer (substrate) accommodated in a cassette such as a FOUP (not shown) into the plating apparatus 1000 and for unloading a substrate from the plating apparatus 1000 to the cassette. In this embodiment, four load ports 100 are arranged in a horizontal line, but the number and arrangement of the load ports 100 are arbitrary. The transfer robot 110 is a robot for transferring a substrate, and is configured to transfer a substrate between the load port 100, the aligner 120, the pre-wet module 200, and the spin rinse dryer 600. When transferring a substrate between the transfer robot 110 and the transfer device 700, the transfer robot 110 and the transfer device 700 can transfer the substrate via a temporary placement table (not shown).

[0012] The aligner 120 is a module for aligning the position of an orientation flat, a notch, etc. of a substrate to a predetermined direction. In this embodiment, two aligners 120 are arranged side by side in the horizontal direction, but the number and arrangement of the aligners 120 are arbitrary. The pre-wet module 200 wets the surface to be plated of the substrate before plating with a treatment liquid such as pure water or degassed water, thereby replacing air inside a pattern formed on the substrate surface with the treatment liquid. The pre-wet module 200 is configured to perform a pre-wet process that makes it easier to supply plating liquid to the inside of the pattern by replacing the treatment liquid inside the pattern with a plating liquid during plating. In this embodiment, two pre-wet modules 200 are arranged side by side in the vertical direction, but the number and arrangement of the pre-wet modules 200 are arbitrary.

[0013] The presoak module 300 is configured to perform a presoak process in which an oxide film with high electrical resistance present on the surface of a seed layer formed on the plated surface of a substrate before plating is etched away with a treatment liquid such as sulfuric acid or hydrochloric acid to clean or activate the surface of the substrate to be plated. In this embodiment, two presoak modules 300 are arranged vertically, but the number and arrangement of the presoak modules 300 are arbitrary. The plating module 400 performs plating on the substrate. In this embodiment, there are two sets of 12 plating modules 400 arranged in a vertical arrangement of three modules and a horizontal arrangement of four modules, for a total of 24 plating modules 400, but the number and arrangement of the plating modules 400 are arbitrary.

[0014] The cleaning module 500 is configured to perform a cleaning process on the substrate to remove plating solution and the like remaining on the substrate after plating. 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 dryer 600 is a module for drying the substrate after cleaning by rotating it at high speed. In this embodiment, two spin rinse dryers 600 are arranged vertically, but the number and arrangement of the spin rinse dryers 600 are arbitrary. The transport device 700 is a device for transporting the substrate between multiple modules in the plating apparatus 1000. The control module 800 is configured to control multiple modules of the plating apparatus 1000, and can be configured from, for example, a general computer or a dedicated computer equipped with an input / output interface with an operator.

[0015] An example of a series of plating processes performed by the plating apparatus 1000 will be described. First, a substrate stored in a cassette is carried into the load port 100. Next, the transfer robot 110 removes the substrate from the cassette of the load port 100 and transfers the substrate to the aligner 120. The aligner 120 aligns the positions of the orientation flat, notch, etc. of the substrate to a predetermined direction. The transfer robot 110 delivers the substrate, whose direction has been aligned by the aligner 120, to the pre-wet module 200.

[0016] The pre-wet module 200 performs a pre-wet process on the substrate. The transport device 700 transports the substrate that has been subjected to the pre-wet process to the pre-soak module 300. The pre-soak module 300 performs a pre-soak process on the substrate. The transport device 700 transports the substrate that has been subjected to the pre-soak process to the plating module 400. The plating module 400 performs a plating process on the substrate.

[0017] The transfer device 700 transfers the plated substrate to the cleaning module 500. The cleaning module 500 performs a cleaning process on the substrate. The transfer device 700 transfers the cleaned substrate to the spin rinse dryer 600. The spin rinse dryer 600 dries the substrate. The transfer robot 110 receives the substrate from the spin rinse dryer 600 and transfers the dried substrate to a cassette on the load port 100. Finally, the cassette containing the substrate is removed from the load port 100.

[0018] It should be noted that the configuration of the plating apparatus 1000 described in FIG. 1 and FIG. 2 is merely an example, and the configuration of the plating apparatus 1000 is not limited to the configuration in FIG.

[0019] The control module 800 may have a configuration including a memory (not shown) that stores various setting data such as machine parameters and various programs, and a CPU (not shown) that executes the programs in the memory. The control module 800 may be provided with an input / output interface including an output device such as a display, and an input device including a keyboard, a mouse, and the like. The storage medium constituting the memory may include any volatile storage medium and / or any non-volatile storage medium. The storage medium may include one or more of any storage media such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD-ROM, and a flexible disk. A part or all of the functions of the control module 800 may be configured with hardware such as an ASIC. A part or all of the functions of the control module 800 may be configured with a PLC, a sequencer, and the like. A part or all of the control module 800 may be disposed inside and / or outside the housing of the plating apparatus 1000. A part or all of the control module 800 is connected to each part of the plating apparatus by wire and / or wirelessly so as to be able to communicate with them.

[0020] [Plating module] Next, a description will be given of the plating module 400. Since the plating modules 400 included in the plating apparatus 1000 according to this embodiment have the same configuration, one plating module 400 will be described.

[0021] FIG. 3 is a schematic diagram of a plating module according to an embodiment. As shown in FIG. 3, the plating apparatus 1000 (plating module 400) according to this embodiment is a plating apparatus (plating module) of a type called a face-down type, a cup type, a horizontal type, or the like, which holds the substrate Wf horizontally and plates it. The plating module 400 according to this embodiment mainly includes a plating tank 410, a substrate holder 11 also called a plating head that holds the substrate Wf, a rotation mechanism, a tilt mechanism, and a lift mechanism (not shown) that rotate, tilt, and lift the substrate holder 11, an anode 430 that is arranged below the substrate Wf and facing the substrate Wf, and a diaphragm 440 that divides the plating tank 410 into a cathode chamber Cca and an anode chamber Can. However, the tilt mechanism may be omitted. An overflow tank 420 that receives the cathode solution Pc that has overflowed from the plating tank 410 is provided outside the plating tank 410.

[0022] The plating tank 410 according to this embodiment is configured as a bottomed container having an opening at the top. The plating tank 410 forms a roughly cylindrical internal space for storing plating solution (cathode solution Pc, anode solution Pa). In this specification, the cathode solution and the anode solution are also referred to as catholyte and anolyte. In this specification, when used in the context of maintaining the composition of the plating solution constant, the plating solution refers to the cathode solution Pc.

[0023] The plating solution may be any solution containing ions of metal elements that constitute the plating film, and the specific example is not particularly limited. In this embodiment, a copper plating process is used as an example of a plating process, and a copper sulfate solution is used as an example of a plating solution. The plating solution may contain a predetermined additive.

[0024] The plating tank 410 is provided with a supply port 411 as an inlet for introducing the anode solution Pa, and a supply port 412 as an inlet for introducing the cathode solution Pc. The overflow tank 420 is provided with a discharge port 413 for discharging the plating solution from the overflow tank 420. In addition, an exhaust passage 417 of the anode chamber Can, which will be described later, is provided with a discharge port 414 for discharging the anode solution Pa in the exhaust passage 417 to the overflow tank 420.

[0025] A paddle (not shown) may be disposed near the substrate Wf inside the plating tank 410. The paddle reciprocates in a direction generally parallel to the surface to be plated of the substrate Wf, generating a strong flow of plating solution on the surface of the substrate Wf. This homogenizes the ions in the plating solution near the surface of the substrate Wf, improving the in-plane uniformity of the plating film formed on the surface of the substrate Wf.

[0026] A porous resistor 450 is disposed below the paddle inside the plating tank 410. Specifically, the resistor 450 is configured by a porous plate member having a plurality of holes (pores). The plating solution below the resistor 450 can pass through the resistor 450 and flow above the resistor 450. The resistor 450 is a member provided to uniformize the electric field formed between the anode 430 and the substrate Wf. By disposing such a resistor 450 in the plating tank 410, the thickness of the plating film (plating layer) formed on the substrate Wf can be easily uniformized. Note that the resistor 450 is not an essential component in this embodiment, and the present embodiment may be configured without the resistor 450.

[0027] An anode mask 431 is disposed below the resistor 450. The anode mask 431 has an opening for exposing the anode 430, and this opening adjusts the area for exposing the anode 430 and adjusts the electric field between the anode and the substrate. The anode mask 431 may be a variable anode mask whose opening dimensions can be adjusted by an actuator or the like. The anode mask 431 may be omitted.

[0028] The diaphragm 440 divides the inside of the plating tank 410 into a cathode chamber Cca and an anode chamber Can below the resistor 450, or below the anode mask 431 in this embodiment. In this embodiment, the diaphragm 440 is a cation exchange membrane that is permeable to cations. The diaphragm 440 may be composed of multiple membranes.

[0029] In this embodiment, the anode 430 is disposed in close contact with the lower surface of the diaphragm 440. The upper surface of the diaphragm 440 may be pressed from above by a diaphragm presser (e.g., a plate-like or sheet-like member having a plurality of holes, e.g., a mesh-like portion) not shown. In this embodiment, an insoluble anode is used as the anode 430. The specific type of the insoluble anode is not particularly limited, and platinum, titanium, iridium oxide, etc. (e.g., IrO2 / Ti, Pt / Ti) can be used. The surface of the anode 430 may further have a topcoat layer for the purpose of suppressing decomposition of additives in the plating solution, etc.

[0030] In this embodiment, the anode 430 is a plate-like member (e.g., a disk-like member) having a large number of through-holes (not shown) connecting the front and back surfaces, and is configured so that the anolyte Pa comes into contact with the diaphragm 440 via the multiple through-holes, and cations in the anolyte Pa can move through the diaphragm 440 to the cathode chamber Cca (cathode liquid Pc).

[0031] The anode 430 and the diaphragm 440 are brought into close contact with each other to prevent gas (e.g., oxygen generated at the anode) from accumulating between the anode 430 and the diaphragm 440 and affecting the electric field and the ion conduction path between the anode and the substrate. The diaphragm 440 is configured to be impermeable to gases such as oxygen generated at the anode.

[0032] A back plate 81 for adjusting the amount of bubbles is disposed below the anode 430 and adjacent to the lower surface of the anode 430 at a predetermined distance. The back plate 81 adjusts the amount of oxygen generated in the anode 430 that accumulates on the lower surface of the anode 430, and prevents a large amount of oxygen from escaping from the lower surface of the anode 430 at once, which would cause large fluctuations in the anode voltage. The back plate 81 allows a certain amount of oxygen to accumulate between the lower surface of the anode 430 and the back plate 81, and oxygen is released and discharged in small amounts so that large fluctuations in the anode voltage can be suppressed. This makes it possible to suppress a decrease in plating quality caused by large fluctuations in the anode voltage.

[0033] Note that, instead of the back plate 81, a ring member of a predetermined height may be provided surrounding the outer periphery side of the lower surface of the anode 430. Even with such a ring member, it is possible to achieve similar or equivalent functions and effects to those of the back plate 81.

[0034] The anode chamber Can is connected to the atmosphere via an exhaust passage 417 extending vertically along the side of the cathode chamber Cca, and is configured to be able to exhaust gas (oxygen) generated in the anode 430 via the exhaust passage 417. When an insoluble anode is used, oxygen is generated by electrolysis of water in the anode 430. A liquid level sensor 415 for detecting the liquid level of the anode fluid is disposed in the exhaust passage 417. The liquid level sensor 415 may be an analog type liquid level sensor capable of continuously detecting the liquid level of the anode fluid. The liquid level sensor 415 may be an on / off type liquid level sensor capable of detecting the lower limit value of the liquid level of the anode fluid. In addition to this, an on / off type liquid level sensor capable of detecting the upper limit value of the liquid level of the anode fluid may be provided. By controlling the amount of the anode fluid so as to maintain the liquid level of the anode fluid at or above the lower limit value, it is possible to prevent the anode fluid from running out. By controlling the amount of the anode fluid so as to maintain the anode fluid level at or below the upper limit, it is possible to suppress or prevent the anode fluid Pa in the anode chamber from which the additive has been consumed from flowing into the overflow tank 420 and being circulated to the cathode chamber Cca. This makes it possible to suppress or prevent a decrease in the concentration of the additive in the cathode fluid in the cathode chamber Cca and deterioration of the additive.

[0035] In this embodiment, a common plating solution having the same composition is introduced into the cathode chamber Cca and the anode chamber Can as the cathode solution Pc and the anode solution Pa. The common plating solution is mainly composed of an aqueous copper sulfate solution and may contain a small amount of hydrochloric acid. Note that this embodiment is also applicable to other types of cathode solutions and anode solutions.

[0036] 3, a circulation circuit 470 that supplies and circulates plating solutions (cathode solution, anode solution) is connected to the plating tank 410. A pure water supply line 474 that supplies pure water (e.g., DIW) to the cathode chamber Cca is also connected to the plating tank 410. The pure water supply line 474 is piped so as to supply pure water (e.g., DIW) to a reservoir tank 481 and a plating solution adjustment tank 482 in the circulation circuit 470 as well.

[0037] 3, the circulation circuit 470 has a reservoir tank 481 and a plating solution adjustment tank 482. The reservoir tank 481 receives the plating solution supplied from the plating solution adjustment tank 482, the plating solution discharged from the overflow tank 420, and DIW, and supplies the plating solution after adjusting the concentration to the cathode chamber Cca and the anode chamber Can as the cathode solution Pc and the anode solution Pa, and also returns the plating solution to the plating solution adjustment tank 482. A fluid line 471 is connected to the output of the reservoir tank 481, and the plating solution is supplied from the reservoir tank 481 to the cathode chamber Cca, the anode chamber Can, and the plating solution adjustment tank 482 by a pump 475 on the fluid line 471. At the output side of the pump 475, the fluid line 471 branches into the plating tank 410 side and the plating solution adjustment tank 482 side, and the fluid line 471 on the plating tank 410 side further branches into the cathode chamber Cca side and the anode chamber Can side. Valves 477 and 478 are provided on the fluid line 471 on the cathode chamber Cca side and the anode chamber Can side, respectively. The valves 477 and 478 may be either an opening / closing valve or a flow rate control valve. By controlling the opening and closing of the valves 477 and 478, the plating solution is supplied to the cathode chamber Cca and the anode chamber Can.

[0038] The plating solution adjustment tank 482 receives the plating solution from the reservoir tank 481, appropriately adds / supplies one or more kinds of additives to the plating solution and powdered copper oxide (CuO) to the plating solution, adjusts the concentration of the plating solution with DIW, and then supplies the plating solution after the concentration adjustment to the reservoir tank 481 via the fluid line 473 by the pump 476. The plating solution adjustment tank 482 is provided with an agitator 483, which is configured to agitate the plating solution so that the additives and copper oxide (CuO) are dissolved in the plating solution.

[0039] The anode chamber Can is supplied with DIW via a pure water supply line 474 and a valve 479. The reservoir tank 481 is supplied with DIW via a pure water supply line 474 and a valve 480. The plating solution adjustment tank 482 is also supplied with DIW via the pure water supply line 474 and a valve (not shown).

[0040] In another embodiment, the reservoir tank 481 and the plating solution adjustment tank 482 may be integrated together. That is, the supply of additives and the replenishment of CuO may be performed in the reservoir tank 481, and the plating solution adjustment tank 482 may be omitted.

[0041] In this embodiment, the circulation circuit 470 circulates the cathode solution Pc in the cathode chamber Cca, while the anode solution Pa is not circulated in the anode chamber Can, and only the liquid level of the anode solution Pa is managed by the liquid level sensor 415. Specifically, when preparing a new plating solution in the plating tank 410, after the plating solution (anode solution Pa, cathode solution Pc) is introduced into the anode chamber Can and the cathode chamber Cca, no plating solution is supplied to the anode chamber Can, and when the level of the anode solution falls below a predetermined lower limit, DIW is replenished to keep the liquid level above the lower limit.

[0042] 4 is an explanatory diagram for explaining the reaction of ions in a plating tank. As shown in the figure, water is electrolyzed at the anode 430, and hydrogen ions H + and oxygen O2 are generated. In addition, copper ions (Cu ions) Cu 2+ and hydrogen ion H + moves into the cathode chamber Cca (cathode fluid Pc) through the diaphragm 440. In the cathode chamber Cca, copper ions Cu 2+ is reduced on the substrate Wf and precipitates as copper (Cu) on the substrate Wf. In addition, CuO is dissolved in the cathode fluid Pc discharged from the cathode chamber Cca in the circulation circuit 470, and copper ions Cu 2+is replenished to the cathode fluid Pc. When electrolysis is performed, a difference in the concentration of cations occurs between the anode chamber Can and the cathode chamber Cca, so hydrogen ions H + and the transfer of copper ions Cu from the cathode chamber Cca to the anode chamber Can. 2+ The movement of ions occurs, but at a slower rate than the movement of ions by electrolysis.

[0043] FIG. 5A is a graph showing the change in concentration of copper (Cu) and sulfuric acid (H2SO4) in the anolyte. FIG. 5B is a graph showing the change in concentration of ions in the anolyte. FIG. 5C is a graph showing the change in transport number of ions permeating the diaphragm. FIG. 5D is a graph showing the change in copper and sulfuric acid concentration in the catholyte when CuO equivalent to the amount of plating deposition is replenished.

[0044] In a typical plating apparatus, when preparing a new plating solution in a plating tank, a solution having the same composition as the cathode solution Pc (plating solution) is introduced into the anode chamber Can as the anode solution Pa. When plating is performed using an insoluble anode, copper is precipitated at the cathode (substrate Wf) in an amount corresponding to the amount of electrolysis (amount of charge flowing due to plating current), and copper ions in the cathode solution Pc are consumed, while acid is generated at the anode 430. For this reason, a metal or metal compound is added and dissolved in the cathode solution in an amount corresponding to the amount of electrolysis (amount of charge) to replenish the metal ions and neutralize the acid. The metal compound can be a metal oxide (CuO), a metal hydroxide (Cu(OH)2, a metal carbonate (CuCO3), or the like.

[0045] When the anode chamber Can and the cathode chamber Cca are isolated by a cation exchange membrane diaphragm 440, both hydrogen ions and metal ions (Cu ions) permeate the cation exchange membrane, and the concentrations of copper and sulfuric acid in the anolyte change as shown in FIG. 5A, and the concentration of ions in the anolyte also changes as shown in FIG. 5B. During electrolysis, the Cu ion concentration gradually decreases and the hydrogen ion concentration increases.

[0046] The transport number of ions passing through the cation exchange membrane during plating changes as shown in FIG. 5C. That is, during plating (especially in the early stage of plating), Cu ions move from the anode chamber Can to the cathode chamber Cca through the cation exchange membrane. Therefore, if the amount of Cu deposited by plating is replenished to the cathode solution, Cu ions will be added excessively to the cathode solution, and the composition of the cathode solution will be shifted as shown in FIG. 5D. In particular, the smaller the ratio of the amount of cathode solution / anode solution, the greater the effect. Therefore, in order to stabilize the cathode solution composition, it is necessary to replenish copper taking into account the amount of Cu ions passing through the diaphragm. Specifically, the amount of copper is replenished by subtracting the amount of Cu ions passing through the diaphragm from the amount of plating deposition (amount of electrolysis).

[0047] 6A to 6D are explanatory diagrams for explaining a method for calculating the replenishment amount of CuO. Here, an example will be explained in which copper oxide (CuO) is replenished to the cathode solution in order to replenish metal and neutralize acid in copper plating.

[0048] In FIG. 6A to FIG. 6C, t H (q) is hydrogen ion H + The transference number of t Cu (q) is Cu ion 2+ In the following explanation, t H , t Cu The transport number is the percentage of the total current carried by a specific ion when a current is passed through an electrolyte solution, and is defined as the number of moles (mol) of ion per 1F (Faraday) x the valence of the ion. 1F stands for the Faraday constant, or Fd, which represents the unit of charge. The Faraday constant is the amount of charge per mol of electrons (or holes), and is also known as the Avogadro constant N A (6.02×10 23 [mol -1 ]) and the elementary charge e(1.60217663×10 -19 [C])

[0049] If a total charge of q [F] is input from the time when the plating solution is newly prepared in the plating tank due to the plating current flowing between the substrate and the anode, then (1 / 2) q [mol] of Cu will be deposited on the substrate Wf. 2+ is a divalent ion, and 2 moles of electrons are input in response to the deposition of 1 mole of copper, so the charge amount [F] is multiplied by (1 / 2) to calculate the number of moles of Cu. Hereinafter, the total amount of charge that has flowed from the time the plating solution is newly prepared in the plating tank is referred to as the total charge amount.

[0050] If the total charge q [F] changes from q1 [F] to q2 [F] during plating, the number of moles of Cu deposited on the substrate during that time is (1 / 2)(q2-q1) obtained by multiplying the change in the total charge q2-q1 by (1 / 2).

[0051] At this time, the amount of charge (mol) carried by the Cu ions moving from the anode chamber Can to the cathode chamber Cca is the transport number t Cu (q) from q=q1 to q=q2. As mentioned above, Cu ions are divalent ions, so the amount (mol) of Cu ions that move from the anode chamber Can to the cathode chamber Cca is calculated by the transport number t Cu It is the integral of (q) from q1 to q2 multiplied by (1 / 2).

[0052] Therefore, the amount (mol) of Cu ions that is net consumed in the cathode fluid, that is, the amount (mol) of copper that needs to be replenished, is expressed as shown in the middle part of equation (1) in FIG. 6A.

[0053] Since the movement of anions through the cation exchange membrane (membrane 440) can be ignored, the ions that carry the current flow from the anolyte to the catholyte through the membrane 440 are hydrogen ions H + and Cu ions 2+ Therefore, t H (q)+t Cu (q) = 1 (see equation (2) in FIG. 6A). Therefore, equation (1) becomes t H(q) (the right side of equation (1) in Figure 6A). In other words, the amount (mol) of Cu ions consumed in the catholyte is expressed as the hydrogen ion H + Transport number t H It can be calculated by integrating (q) from q1 to q2 and multiplying the integral by (1 / 2).

[0054] Hydrogen ion transport number t H (q) can be expressed as a function of the total charge q. In the following explanation, t H The -q curve is also called the correction curve. The correction curve means a curve for correcting the Cu ion concentration in the cathode solution. The CuO supply amount (mol) is the correction curve:t H It can be said to be the area of ​​the -q curve multiplied by (1 / ionic valence).

[0055] If the volume of the anolyte is V [L] and the sulfuric acid concentration in the anolyte is Ca [mol / L], then V, Ca, t H (q), t Cu The relationship between (q) and (q) satisfies the formula (3). Formula (3) can be expressed as formula (4).

[0056] Hydrogen ion H + , Cu ion 2+ The ionic conductivity of each H , Λ Cu , hydrogen ions H in the anolyte + , Cu ion 2+ The concentrations of [H + ], [Cu 2+ ], then each transport number t H (q), t Cu (q) can be expressed as the middle part of equations (5) and (6). Here, in the middle parts of equations (5) and (6), the denominator and numerator are Λ Cu Divide by and the ionic conductivity ratio α = Λ H / Λ Cu Then, the transport number t H (q), t Cu (q) can be expressed as the right-hand side of equations (5) and (6).

[0057] The Cu concentration in the anolyte is C Cu (mol / L), the membrane permeation of anions can be ignored, so the relationship in formula (7) holds. That is, during plating, the sulfuric acid (H2SO4) concentration Ca and Cu concentration C in the anolyte are Cu The sum of is kept constant at C.

[0058] A method for deriving formulas (8) to (12) will be described with reference to Figures 6C and 6D. As shown in Figure 6D, sulfuric acid H2SO4 is ionized in two stages, and in the first stage ionization (dissociation), monovalent hydrogen sulfate ions HSO4 - In the second stage, the divalent sulfate ion SO4 2- The ionization to hydrogen is very small (acid dissociation equilibrium constant Ka = 0.0102). Therefore, the hydrogen ion concentration [H + When calculating , only the second-step equilibrium reaction needs to be considered.

[0059] In FIG. 6C, if the acid dissociation equilibrium constant Ka and the activity coefficient γ are used, the relationship of formula (21) is established. H + , a SO4 2- , a HSO4 - indicate the activities of hydrogen ions, sulfate ions, and hydrogen sulfide ions, respectively. H + , γ SO4 2- , γ HSO4 - are the activity coefficients of hydrogen ion, sulfate ion, and hydrogen sulfide ion, respectively. [H + ], [SO4 2- ], [HSO4 - [Kγ] indicate the concentrations of hydrogen ions, sulfate ions, and hydrogen sulfate ions, respectively. If the first term on the second right side of equation (21) is Kγ, it can be expressed as shown on the third right side. Here, the relationship in equation (22) is derived from the left side and the third right side of equation (21), and Ka / Kγ=Ka'.

[0060] The total CuSO4 concentration in the anolyte is C CuIf the total H2SO4 concentration is Ca, then C Cu =[Cu 2+ ], and equation (23) holds.

[0061] From equations (22) and (23), as shown in equations (24) and (25), [SO4 2- ], [HSO4 - ] can be written.

[0062] Here, since electrical neutrality exists, the relationship in equation (26) holds.

[0063] Substituting equations (24) and (25) into equation (26) and rearranging it, we get [H + If we express the quadratic equation in (27) using the solution formula, we get [H + In equation (8), parameters b and c are expressed by equations (9) and (10). In equation (9), the relationship in equation (7) is used to obtain C Cu is replaced by C-Ca. [Cu 2+ ] can be expressed as equation (12) from equations (23) and (7).

[0064] Ka' is the acid ionization equilibrium constant in the anolyte and can be expressed as equation (11) from equation (22).

[0065] (Estimation of ionic conductivity ratio α) Estimation of the ionic conductivity ratio α (see formulas (5) and (6) in FIG. 6A) will be described with reference to FIG. 7A and FIG. 7B. FIG. 7A shows an example of the configuration of a plating cell (plating tank) used in an experiment to estimate the ionic conductivity ratio α. FIG. 7B is a graph showing the change in Cu concentration in the anolyte by an experiment and a simulation.

[0066] In Fig. 7A, a substrate Wf' and an anode 430' are disposed facing each other, and a diaphragm (ion exchange membrane) 440' that separates the cathode chamber and the anode chamber is disposed between the substrate Wf' and the anode 430'. A Cu concentration meter 416' is disposed in the anode chamber. Also shown in Fig. 7A is a paddle device 460' that stirs the cathode solution.

[0067] Using a plating cell (plating tank) as shown in Figure 7A, an anolyte Pa with known Cu and sulfuric acid concentrations was used to perform plating processing on a substrate Wf at a constant current, and the Cu concentration (or sulfuric acid concentration) in the anolyte Pa was monitored. Here, the cathode solution Pc was periodically replenished with CuO to be deposited by plating. The anolyte Pa was periodically replenished with DIW to compensate for loss due to electro-osmosis and evaporation, to keep the anolyte level constant. In addition, a simulation was performed by changing the value of the ionic conductivity ratio α, and the obtained Cu concentration change curve was compared with the Cu concentration change actually obtained in the experiment to determine the value of α that best reproduced the experimental results. As a result, Ionic conductivity ratio α ≒ 4 The simulation was performed in the same manner as in the simulation example described later, with the acid dissociation equilibrium constant Ka' of sulfuric acid set to 0.25, the Cu concentration in the anolyte Pa, the sulfuric acid concentration, and the amount of the anolyte used in the experiment set to initial values, and the value of α was changed.

[0068] (Estimation of acid dissociation equilibrium constant Ka') Next, we will explain the method for experimentally determining the acid dissociation equilibrium constant Ka' of sulfuric acid. Since the activity coefficient is not 1 at high concentrations (high ionic strength), we adopted a method for experimentally estimating Ka' by preparing solutions with different sulfuric acid concentrations and measuring the pH. The results are shown in Figures 8A and 8B.

[0069] FIG. 8A is a table showing the results of estimating the acid dissociation equilibrium constant Ka'. FIG. 8B is a graph showing the results of estimating the acid dissociation equilibrium constant Ka'. As can be seen from these figures, when Ka'=0.249, the measured pH value and the calculated pH value were roughly in agreement. Based on these results, in this embodiment, the acid dissociation equilibrium constant of sulfuric acid Ka' ≒ 0.25 Let us assume that.

[0070] (Simulation example) Figure 9 shows an example of the numerical values ​​of the parameters used in the simulation to calculate the CuO supplement amount. As shown in the figure, the experimentally obtained ionic conductivity ratio α=Λ H / Λ cu Using the equilibrium constant Ka' of sulfuric acid of ≈4, the initial Cu concentration of the anolyte is 50 g / L (0.787 mol / L), and the initial sulfuric acid concentration of the anolyte is 100 g / L (1.02 mol / L), the constant value C in formula (7) can be set to C = 1.807 (mol / L). Here, the initial concentration refers to the concentration at the time of bath construction. Also, the volume V [L] of the anolyte is constant at 4.25 L. By applying these prerequisites (numerical values) to formulas (8) to (10), the hydrogen ion concentration [H + ] can be expressed as a function of Ca. For convenience of explanation, [H + ]=f1(Ca). f1 is the product of Ca and [H + ] is a function that shows the relationship between [Cu 2+ ] is calculated from equation (12) as [Cu 2+ ]=C-Ca and can be expressed as a function of Ca.

[0071] Next, in formula (5), [H + ]=f1(Ca), [Cu 2+ ]=C-Ca, α=4, then the transport number t H can be expressed as a function of Ca. For convenience, t H =f2(Ca). f2 is the product of Ca and t H is a function that shows the relationship between

[0072] This transport rate t H If we substitute =f2(Ca) into equation (3), we can express dCa / dq as a function of Ca as dCa / dq=f3(Ca), which is a differential equation related to Ca. f2 is a function that shows the relationship between Ca and dCa / dq. This differential equation dCa / dq=f3(Ca) is numerically analyzed to calculate the value of Ca for each total charge amount q. This makes it possible to obtain a curve that shows the relationship between Ca and q (Ca-q curve).

[0073] Next, using the Ca-q curve, the transport number t for each total charge q is calculated from equation (4). H Calculate t H A curve showing the relationship between t and q (correction curve: t H -q curve).

[0074] This correction curve (t H -q curve) in equation (1), t from any change section of the total charge q (from q1 to q2) H By integrating with q, the number of moles of the amount of Cu to be replenished (in this embodiment, CuO) can be obtained.

[0075] (Simulation results) Fig. 10A is a graph showing the results of a simulation of the transport number of hydrogen ions, Fig. 10B is a graph showing an enlarged view of the change in the transport number of hydrogen ions immediately after the electrolyte bath is made up, and Fig. 10C is a graph showing an enlarged view of the change in the transport number of hydrogen ions after the composition of the anolyte has stabilized.

[0076] As shown in FIG. 10A, the transport number t H changes from a value near 0.8 (less than 0.8) to a value close to 1. Figures 10B and 10C are excerpts of a portion of the graph in Figure 10A immediately after bath make-up and a portion after the composition of the anolyte has stabilized. As shown in Figures 10B and 10C, the amount of CuO replenishment (mol) can be determined from the obtained curve. Here, the amount of CuO to be added when replenishing every 50 Ah is determined from the graph. In Figures 10A to 10C, the integral value of the hydrogen ion transport number is shown in [Ah], so the integral value of the hydrogen ion transport number (t H The amount of CuO replenishment [mol] can be calculated by converting the area of ​​the -q curve (area of ​​the -q curve) into [F] and multiplying it by 1 / 2 (see equation (1) in Figure 6A).

[0077] In Fig. 10A-C, the amount of CuO added when replenishing the total charge q = 50 Ah is shown by the correction curve: HThe transport number t of hydrogen ions is determined by the total charge q (horizontal axis in Figures 10A to 10C) after the bath is made. H Since the amount of CuO replenishment varies in each section (each section of the 50 Ah width), the transport number t of hydrogen ions varies depending on the total charge amount, especially until the composition of the anolyte stabilizes (until the Cu concentration becomes sufficiently low). H It is considered that the total charge q changes substantially, and it can be seen that the CuO supply amount also changes with the total charge q (Fig. 10B). On the other hand, after the composition of the anolyte stabilizes (after the Cu concentration becomes sufficiently low), it is considered that the net movement of Cu ions from the anode to the cathode becomes substantially zero, so the CuO supply amount (hydrogen ion transport number t H The integral value of x 1 / 2) is considered to be the amount corresponding to the amount of copper precipitate. Therefore, as shown in FIG. 10C, the hydrogen ion transport number t H is constant and does not change with the total charge q (horizontal axis, Ah), and the hydrogen ion transport number t H The integral value of increases at a constant rate, and the amount of CuO replenished becomes constant.

[0078] (Simplified formula) correction curve t H Instead of calculating the area of ​​-q by integration as described above, a simplified formula for calculating the amount of CuO replenishment by approximating it with the area of ​​a rectangle will be described.

[0079] Fig. 11 shows a simplified formula for calculating the amount of CuO replenishment. Fig. 12A is a graph showing the change in hydrogen ion transport number. Fig. 12B is a graph showing an enlarged view of the change in hydrogen ion transport number immediately after bath make-up. Fig. 12C is a graph showing an enlarged view of the change in hydrogen ion transport number after the anolyte composition has been stabilized. In Figs. 12A to 12C, the horizontal axis of the graph shows the total charge (Ah) immediately after bath make-up, and the vertical axis shows the hydrogen ion transport number.

[0080] As described above, when supplying CuO to the cathode fluid, it is sufficient to add CuO to the cathode fluid in an amount equivalent to the amount of hydrogen ions that have moved from the anode chamber to the cathode chamber due to electrolysis. In the same manner as described above, the relationship between the amount of electrolysis (total charge amount) and the amount of hydrogen ions that move is obtained in advance by simulation, and a correction curve (t H Using this correction curve, the total charge amount qc from the time of bath construction to the time of replenishment, and the total charge amount q from the time of bath construction to the time of the previous replenishment are calculated using the formula (1A) in FIG. p The amount of CuO to be supplied (mol) is determined from the above. In the formula (1A) of FIG. 11, q1 and q2 in the formula (1) are respectively set to q c , q p q1, q2 and q c , q p may be interchangeable with each other.

[0081] CuO replenishment interval is t H If the change in hydrogen ion transport number t H Instead of calculating the CuO replenishment amount by integrating with the total charge q, the correction curve: H The integral value can be approximated by the area of ​​the rectangle in the replenishment interval of the -q curve. In FIG. 12B, the total charge q [F] is q p [F]=50[Ah] to q c Considering the interval [F]=100[Ah], t in this interval H The area / integral value of q=q p From q=q c In H The average value of (the length of the vertical axis), that is, (1 / 2)(t H (q p )+t H (q c )) the change in q in this section, q c -q p (The length of the horizontal axis) is multiplied to obtain the area of ​​the rectangle. Therefore, the integral part of equation (1) is (1 / 2)(t H (q p )+t H (q c))×(q c -q p ) the amount of CuO replenishment (mol) can be calculated as shown in formula (1A). However, since the unit of charge in formula (1A) is F, the value converted from the charge [Ah] to [F] is used. Formula (1A) shows (1 / 2) × (area of ​​a rectangle).

[0082] When the replenishment interval is short, the correction curve:t H In the -q curve, the total charge q from the time of bath preparation to the last replenishment p (F) and the total charge q from the time of bath construction to the time of this replenishment c By calculating the area of ​​the rectangle between (F), the amount of CuO replenishment (mol) can be calculated easily and accurately.

[0083] As in the example of Figs. 10A-C, in Figs. 12A-C, the amount of CuO added when replenishment is performed every 50 Ah is determined from the correction curve. As in the above, the transport number t H Since the amount of CuO replenishment varies in each section (each section of the 50 Ah width section), the amount of CuO replenishment varies in each section (each section of the 50 Ah width section). In particular, until the composition of the anolyte stabilizes, the transport number t of hydrogen ions varies depending on the total charge q as shown in FIG. 12B. H changes, and the CuO supply amount (rectangle area × 1 / 2) also changes depending on the total charge amount q. On the other hand, after the composition of the anolyte stabilizes, the hydrogen ion transport number t H remains constant without changing, and the amount of CuO replenishment (area of ​​the rectangle × 1 / 2) does not change due to the total charge amount q and remains constant.

[0084] FIG. 13A shows the change in ion concentration in the cathode solution when CuO equivalent to the plating deposition amount is replenished. FIG. 13B shows the transport number t H The change in ion concentration in the cathode solution when CuO is replenished based on the curves of . As can be seen from the comparison of these graphs, in contrast to the shift in the composition of the cathode solution when CuO equivalent to the plating deposition amount is replenished, the transference number tH Based on the curves, it can be seen that by supplementing CuO the catholyte composition remains constant.

[0085] (Control example) The replenishment of CuO is performed by controlling the replenishment device 485 by the control module 800 . (1) Correction curve t calculated by simulation H -q (FIGS. 10A and 12A) is stored in a storage device, and the amount of CuO to be replenished (mol) is calculated from formula (1) or (1A) according to the total charge amount q (calculated from the plating current and plating time), and CuO can be replenished to the cathode solution. When formula (1) is used, a correction curve t is plotted at predetermined intervals at intervals of a predetermined total charge amount q as shown in FIG. 10B and FIG. 10C. H When formula (1A) is used, the correction curve t is drawn at intervals of a predetermined total charge amount q as shown in FIG. 12B and FIG. 12C. H CuO of an amount equal to the area of ​​the rectangle x (1 / 2) of the area of ​​-q can be replenished. The total charge amount q can be calculated from the plating current and plating time (time integral of the plating current, or multiplication of the plating current and plating time). (2) Correction curve t calculated by simulation H -q area or supply amount (= correction curve t H -q area × (1 / 2)) may be stored in the storage device for each section of the total charge amount q. In this case, the storage device outputs a correction curve t H The area of ​​-q or the amount of replenishment can be read out to replenish CuO. H When the area of ​​-q is stored, the amount of supply can be calculated by multiplying it by 1 / 2.

[0086] <Second embodiment> (Correction of CuO replenishment amount for different plating solution compositions) The second embodiment will be described with respect to the points that are different from the first embodiment, and a description of the points that are the same as the first embodiment will be omitted.

[0087] 14A-D show the change in hydrogen ion transport number and the change in ion concentration in the cathode solution for different plating solution compositions. The Cu concentration and the concentration ratio Cu / H2SO4 show the initial Cu concentration (at the time of bath make-up) in the anode solution and the concentration ratio Cu / H2SO4. As can be seen from these graphs, when the plating solution composition is different, it is necessary to determine the amount of CuO to be replenished and correct the ion concentration in the cathode solution using a different correction curve (a curve showing the change in hydrogen ion transport number).

[0088] FIG. 15A shows the hydrogen ion transport number t H The change curve of the hydrogen ion transport number t H The change curve of is shown.

[0089] As shown in Fig. 15A, when the Cu / H2SO4 ratio is constant, the initial hydrogen ion transport number t H The transport number t of hydrogen ions increases with increasing amount of electrolysis (total charge) as the Cu concentration increases. H In addition, when the Cu concentration is constant, the higher the Cu / H2SO4 ratio, the slower the initial hydrogen ion transport number t H As the amount of electrolysis (total charge) increases, the transport number t H Based on the above considerations, a correction curve (t H -q curve) obtained by simulation H We investigated a method to obtain an approximation curve for the -q curve and automatically determine the coefficients of the approximation curve according to the plating solution composition.

[0090] FIG. 16A shows the correction curve: H The formula for the approximate curve of the -q curve is shown below. Equation (31) is expressed as CuIn, t H Equation (31A) is an equation that represents the approximate curve of the initial Cu concentration C Cu When = 50g / L, t H These are mathematical expressions that represent the approximate curve of the -q curve. In these expressions, a1, a2, and a3 are coefficients. In the following description, any of the coefficients a1, a2, and a3 may be referred to as an.

[0091] FIG. 16B and FIG. 16C show the relationship between t H 16B is a table and a graph showing an example of calculation of coefficients a1, a2, and a3 of a formula representing an approximation curve of the -q curve. Cu = 50g / L (fixed), and the initial concentration ratio Cu / H2SO4 was changed, and t H The -q curve was calculated and the t obtained from the simulation H The coefficients a1, a2, and a3 were calculated by the least squares method using the -q curve. The results are shown in Figure 16B. The results of Figure 16B are shown in a graph in Figure 16C. The horizontal axis of the graph is the initial concentration ratio Cu / H2SO4 in the anolyte, and the vertical axis is the coefficients a1, a2, and a3.

[0092] The relationship between the coefficients a1, a2, and a3 in FIG. 16C and the concentration ratio Cu / H2SO4 is approximated by a third-order polynomial (approximation equation, approximation curve) as shown in equation (32) in FIG. 16D. n1 ~k n4 The coefficient k n1 ~k n4 can be calculated, for example, by the least squares method. The result is shown in FIG. 16E. In FIG. 16E, k n1 ~k n4 For example, in FIG. 16E, k1 for a1 is k 11 Corresponds to.

[0093] Fig. 17 shows a formula for calculating the CuO replenishment amount for an arbitrary plating solution composition. First, the coefficient k n1 ~k n4Calculate the coefficients a1, a2, and a3 from the value of the initial Cu concentration C Cu Based on [g / L], the correction curve: t H - Calculate q. Correction curve: t H Using -q, the amount of CuO replenished (mol) can be calculated from formula (1A). At this time, the amount of CuO replenished (mol) may be calculated by integral calculation as in the middle side of formula (1A), or, if the replenishment interval is short, the amount of CuO replenished (mol) may be calculated by calculating the area of ​​a rectangle as in the right side of formula (1A). According to this calculation method, it is possible to obtain a correction curve:t for a plating solution of any plating solution composition without performing a simulation for each plating composition. H You can get -q.

[0094] 18A to 18D show the approximation curve of the correction curve applicable to any plating solution composition, and the simulation results of adjusting the ion concentration in the cathode solution using the approximation curve. These figures show that the calculation method using the approximation curve of FIG. 17 can replenish an appropriate amount of CuO in a plating solution of any composition, thereby stabilizing the ion concentration in the cathode solution.

[0095] (Control example) The replenishment of CuO is performed by controlling the replenishment device 485 by the control module 800 . (1) Correction curve t calculated by simulation H -q (equation (31) in FIG. 17) is stored in a storage device, and the CuO supply amount (mol) is calculated from equation (1) or (1A) according to the total charge amount q (calculated from the plating current and plating time) in the same manner as in the first embodiment, and CuO can be supplied to the cathode solution. Note that the data set (q,t H ) may be stored in a storage device. The total charge amount q can be calculated from the plating current and plating time (time integral of the plating current, or multiplication of the plating current and plating time). (2) Similar to the first embodiment, the correction curve t calculated by simulation H-q area or supply amount (= correction curve t H -q area × (1 / 2)) may be stored in the storage device for each section of the total charge amount q. In this case, the storage device outputs a correction curve t H -q area or supply amount (= correction curve t H -q area × (1 / 2)) and CuO can be replenished. Correction curve t H When the area of ​​-q is stored, the amount of supply can be calculated by multiplying it by 1 / 2.

[0096] <Third embodiment> (Calculation of CuO supplement amount when directly monitoring ion concentration) The third embodiment will be described with respect to the points that are different from the first and second embodiments, and a description of the points that are the same as the first and second embodiments will be omitted.

[0097] Fig. 19A is an explanatory diagram for explaining a method for calculating the CuO replenishment amount when the ion concentration in the anolyte is directly monitored, and Fig. 19B shows an example of the configuration of a plating module when the ion concentration in the anolyte is directly monitored.

[0098] 19B shows the configuration of FIG. 3 with some of the configuration such as the circulation circuit, the supply port, and the discharge port connected to the plating module 400 omitted. The configuration of FIG. 19B differs from the configuration of FIG. 3 in that a Cu concentration meter 416 is disposed in the anode chamber Can. The other configurations can be the same as those of FIG. 3.

[0099] Transport number t of hydrogen ion H can be expressed by equation (5) shown in FIG. 6A. + ], Cu ion concentration [Cu 2+ 6B. However, in FIG. 19A, in the equations (9) and (10) of FIG. 6B, equation (7) is used to express b and c as the Cu concentration C as shown in equations (9') and (10'). CuUsing the previously mentioned α = 4, Ka' = 0.25, C = 1.807 (mol / L), and V = 4.25L (Figure 9), the Cu ion concentration [Cu 2+ ]=C Cu By detecting the hydrogen ion concentration [H + ] can be calculated, and the hydrogen ion concentration [H + ] and Cu ion concentration [Cu 2+ ] to equation (5), the hydrogen ion transport number t H Then, the hydrogen ion transport number t H From this, the amount of CuO replenishment (mol) can be calculated using formula (1A).

[0100] In actual control, the formulas shown in FIG. 19A are stored in a storage device, and the Cu ion concentration [Cu 2+ ] is detected, and the hydrogen ion concentration [H + ] was calculated, and the Cu ion concentration [Cu 2+ ] and hydrogen ion concentration [H + ] into equation (5) to obtain the hydrogen ion transport number t H Calculate the amount of CuO to be supplied (mol) from equation (1A). Cu ion concentration [Cu 2+ ] is continuously detected, and the hydrogen ion transport number t H is continuously calculated and the correction curve t H The amount of CuO replenished (mol) can be calculated by integral calculation for each section of the total charge amount q, as shown in the middle of the formula (1A). In addition, when the replenishment interval is short, the q at both ends of the section of the total charge amount q can be calculated. p , q c In the hydrogen ion transport number t H The amount of CuO replenishment (mol) can be calculated by substituting the amount of CuO replenishment (mol) into the right side of equation (1A). The total charge amount q can be calculated from the plating current and plating time (time integral of the plating current, or multiplication of the plating current and plating time).

[0101] According to this calculation method, the Cu ion concentration during plating [Cu 2+ ]=Cu concentration C Cu By directly detecting this, the amount of CuO replenished (mol) can be calculated with higher accuracy.

[0102] In addition to detecting the Cu ion concentration, a hydrogen ion concentration meter was installed in the anolyte to measure the hydrogen ion concentration [H + Using the detected values ​​of Cu ion concentration and hydrogen ion concentration, the hydrogen ion transport number t H Then, the hydrogen ion transport number t H From the above, the CuO supply amount (mol) can be calculated by the formula (1A). According to this calculation method, the CuO supply amount (mol) can be calculated more accurately by directly detecting both the Cu ion concentration and the hydrogen ion concentration during plating.

[0103] In actual control, the formula (5) shown in FIG. 19A is stored in a storage device, and the Cu ion concentration [Cu 2+ ], hydrogen ion concentration [H + ] and the Cu ion concentration [Cu 2+ ] and hydrogen ion concentration [H + ] into equation (5) to obtain the hydrogen ion transport number t H The amount of CuO supplied (mol) is calculated from the formula (1A). The integral calculation or rectangular area approximation calculation using the formula (1A) can be performed in the same manner as described above.

[0104] After the concentration of Cu ions in the anolyte falls below a certain value (after the composition of the anolyte stabilizes), the hydrogen ion transport number t HIt is also possible to supply a replenishment amount of CuO corresponding to the amount of copper deposited on the substrate Wf without calculating q. In this way, after the concentration of Cu ions in the anolyte falls below a predetermined value, the replenishment amount can be determined based only on the change in the total charge amount without considering the amount of Cu ions passing from the anolyte to the cathode liquid, and calculation of the replenishment amount is simplified. After the composition of the anolyte is stabilized, in equations (1) and (1A), CuO (mol)=(1 / 2)×(q c -q p ), or (1 / 2) × (q2-q1). In the first and second embodiments, the total charge amount q at which the concentration of Cu ions in the anolyte falls below a predetermined value is calculated in advance, and the hydrogen ion transport number t H Alternatively, it is possible to replenish CuO in an amount corresponding to the amount of copper deposited on the substrate Wf without calculating the above.

[0105] <Fourth embodiment> Figure 20 shows a formula for calculating the CuO replenishment amount when the plating solution (cathode solution) of multiple plating tanks or cells is connected and the solution is managed collectively. Let x (x=1 to m) be the cell number, and q be the total charge of each cell at the time of the nth replenishment after the bath construction. x,n If (F), the n-th CuO replenishment amount (mol) can be expressed as in formula (1B). That is, the CuO replenishment amount (mol) in the batch liquid management can be calculated as the total CuO replenishment amount (mol) obtained by adding up the CuO replenishment amount (mol) calculated for each cell using formula (1) or (1A). This embodiment is applicable to any of the above-mentioned embodiments.

[0106] <Effect of cation movement due to diffusion> Fig. 21A is a schematic diagram of the plating module, enlarging the vicinity of the diaphragm 440. Fig. 21B is an explanatory diagram for explaining the movement of ions by diffusion through the diaphragm 440.

[0107] During plating, the amount of ion movement due to electrolysis is greater than the amount of ion movement due to diffusion, so the effect of diffusion can be almost negligible. However, when plating is not performed, cations move (exchange) between the anolyte and the catholyte, and the composition may change. However, in the anode-diaphragm contact structure of this embodiment (FIGS. 3 and 21A), an oxygen layer 433 is formed in the gap between the lower surface of the anode 430 and the upper surface of the back plate 432, and the anolyte Pa is not circulated and remains stationary. Therefore, the movement of ions through the diaphragm 440 due to diffusion is restricted, and the concentration change due to diffusion can be almost negligible. Therefore, the amount of CuO to be replenished can be calculated accurately by the above-mentioned simulation without considering the effect of ion movement due to diffusion.

[0108] (Other embodiments) (1) In the above, an example of replenishing a metal oxide (for example, CuO in the case of copper) was given, but instead of a metal oxide, a metal hydroxide (for example, Cu(OH)2 in the case of copper), a metal carbonate (for example, CuCO3 in the case of copper), etc. may be used. (2) In the above, copper plating has been taken as an example for explanation, but the replenishment metal or metal compound (oxide, hydroxide, carbonate, etc.) may be appropriately selected depending on the metal to be plated.

[0109] At least the following aspects can be understood from the above-described embodiment. [1] According to one embodiment, there is provided a plating apparatus for plating a substrate, comprising: a plating tank; a cation exchange membrane dividing the plating tank into an anode chamber for holding an anolyte and a cathode chamber for holding a cathode liquid; an anode disposed in the anode chamber; a replenishing device for replenishing the cathode liquid with the same metal as the metal deposited on the substrate, or a metal compound containing the metal; and a control device for controlling the replenishing device to replenishing the metal or the metal compound containing the replenishing amount of the metal, which is an amount obtained by subtracting the amount of metal ions of the metal that permeated from the anode chamber to the cathode chamber through the cation exchange membrane from the amount of the metal deposited on the substrate, from the amount of the metal deposited on the substrate.

[0110] According to this embodiment, the metal is replenished to the cathode fluid in consideration of the amount of cations (metal ions) that move from the anode fluid to the cathode fluid through the cation exchange membrane, so that deviation in the composition of the cathode fluid caused by excess metal ions in the cathode fluid can be suppressed or prevented, thereby suppressing or preventing deterioration of plating quality. Immediately after preparing a new plating solution (cathode solution, anode solution), the concentration of metal ions in the anode solution is high and the amount of metal ions that migrate from the anode solution to the cathode solution through the cation exchange membrane is large, so if the amount of metal deposited by plating is replenished to the cathode solution, excessive metal ions will be added to the cathode solution, causing the liquid composition of the cathode solution to change. Therefore, it is preferable to replenish metal to the cathode solution, taking into consideration the amount of metal ions that migrate through the cation exchange membrane, at least until the concentration of metal ions in the anode solution falls below a predetermined value.

[0111] [2] According to one embodiment, when a total charge amount is defined as a total amount of charge supplied by a plating current flowing between the substrate and the anode from the time when the anolyte and the catholyte are newly prepared and made up in the plating tank, the replenishment amount is calculated based on an area of ​​a correction curve showing the relationship between the total charge amount and the transport number of hydrogen ions permeating from the anode chamber to the cathode chamber through the cation exchange membrane.

[0112] The correction curve may be data associating the transport number of hydrogen ions with the total charge amount, or may be a formula showing the relationship between the transport number of hydrogen ions and the total charge amount. Calculation based on the area of ​​the correction curve includes integrating the area of ​​the correction curve, calculating the area using a formula for calculating the area when the area of ​​the correction curve is approximated by a rectangle, and calculating the area of ​​the correction curve by any other method.

[0113] According to this embodiment, when a current is passed through an electrolyte solution, the amount (mol) of hydrogen ions that have permeated the cation exchange membrane can be calculated using the transport number, which is the ratio of the current carried by a specific ion to the total current and is defined as the number of moles (mol) of ions per 1 F (Faraday) x the valence of the ion. Since the movement of anions through the cation exchange membrane can be ignored, the ions that carry the current passing through the cation exchange membrane from the anolyte to the catholyte are hydrogen ions and copper ions, so the sum of the transport number of the hydrogen ions and the transport number of the copper ions is 1, and so (transport number of hydrogen ions) = 1 - (transport number of copper ions). Since (1-copper ion transport number) corresponds to twice the number of moles of copper / copper ion obtained by subtracting the amount of metal ions of the metal that permeated from the anode chamber to the cathode chamber through the cation exchange membrane from the amount of plating deposition of the metal on the substrate per 1F, the supply amount (mol) can be calculated based on the area of ​​the correction curve corresponding to the value obtained by adding up 1-copper ion transport number (= hydrogen ion transport number) for each total charge amount. For example, in the case of copper, since it is a divalent ion, the supply amount (mol) of copper is calculated by multiplying the area of ​​the correction curve by 1 / (ion valence)=1 / 2.

[0114] [3] According to one embodiment, the control device replenishes the replenishment amount of the metal or the metal compound containing the replenishment amount of the metal from the replenishment device to the cathode liquid multiple times, and when the total charge amount changes from a first charge amount to a second charge amount, an area of ​​the correction curve is calculated as an integral value obtained by integrating the correction curve from the first charge amount to the second charge amount.

[0115] According to this aspect, the area of ​​the correction curve can be calculated with high accuracy by integrating the correction curve.

[0116] [4] According to one embodiment, the control device replenishes the replenishment amount of the metal or the metal compound containing the replenishment amount of the metal from the replenishment device to the cathode liquid multiple times, and when the total charge amount changes from a first charge amount to a second charge amount, the area of ​​the correction curve is calculated as a value obtained by approximating the area of ​​the correction curve in the section from the first charge amount to the second charge amount using an area of ​​a rectangle.

[0117] According to this embodiment, the area of ​​the correction curve can be calculated by a simple calculation by approximating the area of ​​the correction curve with the area of ​​a rectangle. The correction curve is the relationship between the transport number of hydrogen ions and the total charge amount, and the transport number of hydrogen ions changes depending on the total charge amount. However, when a metal or metal compound is replenished at intervals where the total charge amount changes slightly, the transport number of hydrogen ions changes linearly and approximately in proportion to the total charge amount (note that after the composition of the anode fluid is stabilized, the transport number of hydrogen ions does not change with respect to the total charge amount). Therefore, by approximating the area of ​​the correction curve with a rectangle, the area of ​​the correction curve in the section corresponding to the change in the total charge amount can be calculated with high accuracy.

[0118] [5] According to one embodiment, the area of ​​the correction curve is calculated by multiplying an average value of a transport number of the hydrogen ion for the first charge amount and a transport number of the hydrogen ion for the second charge amount by a difference between the second charge amount and the first charge amount.

[0119] According to this embodiment, when the correction curve changes linearly or in a section where the correction curve does not change, the area of ​​the correction curve in the section can be accurately approximated as the area of ​​a rectangle having one side dimension equal to the average value of the transport numbers of the hydrogen ions at both ends of the section and the adjacent side dimension equal to the change in the total charge amount.

[0120] [6] According to one embodiment, the correction curve is an approximation curve calculated using an initial concentration of the metal ions in the anolyte and a ratio of the initial concentration of the metal ions to an initial concentration of an acid, and the control device calculates an area of ​​the correction curve using the approximation curve of the correction curve, and calculates the replenishment amount based on the area.

[0121] According to this embodiment, it is possible to obtain an approximation curve of the correction curve by a simple calculation according to the composition of the plating solution without performing a simulation to calculate a correction curve for each composition of the plating solution. Note that the initial concentration means the concentration at the time of newly preparing the plating solution in the plating tank.

[0122] [7] According to one embodiment, the control device further includes a memory device that stores the correction curve calculated by simulation, and the control device refers to the correction curve in the memory device to calculate an area of ​​the correction curve, and determines the replenishment amount based on the area of ​​the correction curve.

[0123] According to this embodiment, by storing the correction curve calculated by simulation in the storage device, the replenishment amount can be calculated by simple calculation during plating, and the metal or metal compound can be replenished.

[0124] [8] According to one embodiment, the device further includes a memory device that stores data correlating the total charge amount calculated by simulation with the replenishment amount, and the control device determines the replenishment amount by referring to the data in the memory device.

[0125] According to this embodiment, the metal or metal compound can be replenished during plating with simple control.

[0126] [9] According to one aspect, the control device replenishes the replenishment amount of the metal, or the metal compound containing the replenishment amount of the metal, to the catholyte each time the total charge changes by a predetermined charge amount based on an area of ​​the correction curve during the change.

[0127] According to this embodiment, since the metal or metal compound is replenished every time the preset total charge amount changes, the replenishment amount corresponding to the charge amount at the replenishment timing can be calculated in advance before plating processing and stored in the storage device. Therefore, during plating, the total charge amount is monitored, and the storage device is referred to to determine the replenishment amount corresponding to the total charge amount, and the metal or metal compound can be replenished.

[0128]

[10] According to one embodiment, the control device further includes a first concentration sensor that detects a concentration of metal ions in the anolyte, and the control device calculates the correction curve based on a detection value of the concentration of the metal ions detected by the first concentration sensor, and determines the replenishment amount based on an area of ​​the correction curve.

[0129] According to this embodiment, the correction curve can be calculated with higher accuracy based on the metal ion concentration in the anolyte during plating.

[0130]

[11] According to one embodiment, the control device further includes a second concentration sensor that detects a concentration of hydrogen ions in the anolyte, and the control device calculates the correction curve based on the detection values ​​of the metal ion concentrations and the hydrogen ion concentrations detected by the first and second concentration sensors, and determines the replenishment amount based on an area of ​​the correction curve.

[0131] According to this embodiment, the correction curve can be calculated with higher accuracy based on the metal ion concentration and hydrogen ion concentration in the anolyte during plating.

[0132]

[12] According to one embodiment, the replenishment amount is calculated by dividing the area of ​​the calibration curve by the valence of the metal ion.

[0133] According to this embodiment, the amount of metal or metal compound to be replenished can be accurately calculated from the transport number of hydrogen ions, taking into account the valence of the metal ions.

[0134]

[13] According to one embodiment, the system further includes a circulation circuit connected to the cathode chamber and circulating the cathode fluid in the cathode chamber, the circulation circuit having a pump for pumping the cathode fluid, wherein the replenishing device supplies and dissolves the metal or a compound of the metal to the cathode fluid in a flow path of the circulation circuit, and the control device controls the pump to circulate the cathode fluid in the cathode chamber through the circulation circuit and controls the replenishing device to replenishing the replenishment amount of the metal or the compound of the metal from the replenishing device to the cathode fluid in the flow path of the circulation circuit.

[0135] According to this embodiment, since the replenishing device is disposed in the flow path of the circulation circuit of the cathode liquid, it is possible to avoid complicating the configuration of the plating tank. When a reservoir tank and / or a plating solution adjustment tank are provided in the circulation circuit, for example, a replenishing device may be provided in the reservoir tank and / or the plating solution adjustment tank to supply / dissolve metal or metal ions in the cathode liquid in the reservoir tank and / or the plating solution adjustment tank.

[0136]

[14] According to one aspect, the control device supplies the deionized water to the anode chamber in response to detecting that the amount of the anolyte has fallen below a predetermined lower limit.

[0137] According to this embodiment, the amount of the anolyte can be controlled to be equal to or greater than the lower limit without circulating the anolyte, making it easier to control the amount of the anolyte. The amount of the anolyte can be controlled, for example, by detecting the level of the anolyte with a level sensor in the gas exhaust passage leading to the anode chamber. Furthermore, by maintaining the amount of anolyte at or above the lower limit, it is possible to prevent the anolyte from running out. When a configuration is adopted in which the anode is in close contact with the underside of the ion exchange membrane, if the liquid level of the anode fluid is controlled to a lower limit value that is higher than the liquid level of the cathode fluid, the liquid pressure of the anode fluid will be higher than the liquid pressure of the cathode fluid, and the anode will be pressed against the ion exchange membrane from the anode fluid side, thereby improving the adhesion between the anode and the ion exchange membrane.

[0138]

[15] According to one aspect, the controller drains the anolyte from the anode chamber in response to detecting that the amount of the anolyte has exceeded a predetermined upper limit.

[0139] According to this embodiment, it is possible to prevent the anode fluid from overflowing from the plating tank and being discharged to the outside (for example, into an overflow tank), and thus it is possible to suppress or prevent a decrease in the concentration or deterioration of the additives in the cathode fluid in a configuration in which the anode fluid is circulated from the overflow tank to the cathode chamber.

[0140]

[16] According to one embodiment, the anode is in intimate contact with the lower surface of the ion exchange membrane.

[0141] According to this embodiment, it is possible to suppress or prevent gas (for example, oxygen) generated at the anode from accumulating between the ion exchange membrane and the anode and adversely affecting the plating current.

[0142]

[17] According to one embodiment, the device further comprises a back plate spaced a predetermined distance from a lower surface of the anode.

[0143] According to this embodiment, the amount of gas (oxygen) generated at the anode and accumulated on the lower surface of the anode can be adjusted by the back plate. This makes it possible to suppress or prevent a large amount of gas from escaping from the lower surface of the anode at once, causing fluctuations in the anode voltage and resulting in a decrease in plating quality. In addition, since the entire lower surface of the anode can be stably covered with a gas layer, the amount of ions diffusing from the anolyte through the diaphragm to the catholyte can be suppressed, and it is possible to eliminate the need to consider the movement of ions due to diffusion in the calculation of the hydrogen ion transport number.

[0144]

[18] According to one embodiment, after a concentration of the metal ions in the anolyte falls below a predetermined value, the control device supplies a replenishment amount of the metal, or the metal compound containing the replenishment amount of the metal, which corresponds to an amount of the metal plated onto the substrate, to the catholyte from the replenishment device.

[0145] According to this embodiment, after the concentration of metal ions in the anolyte falls below a predetermined value, the replenishment amount can be determined based only on the change in the total charge amount without taking into consideration the permeation amount of metal ions moving from the anolyte to the catholyte, and therefore calculation of the replenishment amount can be simplified.

[0146]

[19] According to one embodiment, when the anolyte and the catholyte are newly prepared in the plating tank, the plating tank holds the anolyte and the catholyte having the same composition.

[0147] According to this embodiment, since a common plating solution is supplied to the anode chamber and the cathode chamber, there is no need to provide separate supply sources (reservoirs), pumps, etc. for the anode fluid and the cathode fluid, and the supply sources (e.g., reservoirs), pumps, etc. for the anode fluid and the cathode fluid can be shared.

[0148]

[20] According to one embodiment, there is provided a plating method for plating a substrate, comprising the steps of: supplying a replenishment amount of the metal, or a compound of the metal containing the replenishment amount of the metal, to a cathode solution, the replenishment amount being an amount obtained by subtracting an amount of metal ions of the metal that have permeated from the anode chamber to the cathode chamber through an ion exchange membrane that separates the anode chamber and the cathode chamber in a plating tank from the amount of metal deposited on the substrate.

[0149] Although the embodiment of the present invention has been described above, the above-mentioned embodiment of the invention is intended to facilitate understanding of the present invention and does not limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention naturally includes equivalents thereof. Furthermore, within the scope of being able to solve at least a part of the above-mentioned problems or to achieve at least a part of the effects, any combination of the embodiments and modifications is possible, and any combination or omission of each component described in the claims and specification is possible. The specifications, drawings, and abstracts of Japanese Patent No. 6,767,243 (Patent Document 1) and Japanese Patent No. 7,165,843 (Patent Document 2) are incorporated by reference in their entirety into the present specification. [Explanation of symbols]

[0150] 11 Substrate holder 400 Plating Module 410 Plating tank 411, 412 Supply port 413, 414 outlet 415 Liquid level sensor 416 Cu concentration meter 417 Exhaust passage 420 Overflow tank 430 Anode 431 Anode Mask 432 Back Plate 433 Oxygen Layer 440 Diaphragm 450 Resistor 470 Circulation circuit 471, 472, 473 Fluid Lines 474 Pure water supply line 475, 476 Pump 477, 478, 479, 480 Valves 481 Reservoir Tank 482 Plating solution adjustment tank 483 Stirring device 485 Supply device 100 Loading Port 110 Transport Robot 120 Alaina 200 Pre-wet module 300 Presoak Module 400 Plating Module 500 Cleaning Module 600 Spin Rinse Dryer 700 Transport Equipment 800 Control Module 1000 Plating Equipment

Claims

1. A plating apparatus for plating a substrate, comprising: A plating tank; a cation exchange membrane that divides the inside of the plating tank into an anode chamber that holds an anolyte and a cathode chamber that holds a cathode solution; an anode disposed in the anode chamber; a replenishing device for replenishing the catholyte with the same metal as that to be deposited on the substrate or a metal compound containing the same metal; a control device that controls the replenishing device and replenishing the metal or the metal compound containing the replenishing amount of the metal from the replenishing device to the cathode solution, the replenishing amount being an amount obtained by subtracting an amount of metal ions of the metal that have permeated from the anode chamber to the cathode chamber through the cation exchange membrane from an amount of the metal deposited on the substrate by plating; Equipped with the metal is contained as a cationic metal ion in the anolyte and the catholyte, and is reduced and deposited as a plating film on the substrate.

2. 2. The plating apparatus according to claim 1, When the total charge amount is defined as the total charge amount supplied by the plating current flowing between the substrate and the anode from the time when the anolyte and the catholyte were newly prepared in the plating tank, The amount of replenishment is The calculation is based on the area of ​​a correction curve showing the relationship between the transport number of the hydrogen ions permeating from the anode chamber to the cathode chamber through the cation exchange membrane and the total amount of charge. In a graph showing the correction curve, the vertical axis and the horizontal axis respectively represent the transport number of the hydrogen ions and the total amount of charge. When the total amount of charge changes from a first amount of charge to a second amount of charge, the area of ​​the correction curve is calculated based on the area of ​​the correction curve, the horizontal axis, a straight line where the total amount of charge is the first amount of charge, and a straight line where the total amount of charge is the second amount of charge. The area enclosed by the straight line is Plating equipment.

3. 3. The plating apparatus according to claim 2, the control device replenishes the replenishment amount of the metal or the metal compound containing the replenishment amount of the metal from the replenishment device to the catholyte a plurality of times; a plating apparatus, wherein, when the total charge amount changes from a first charge amount to a second charge amount, an area of ​​the correction curve is calculated as an integral value obtained by integrating the correction curve from the first charge amount to the second charge amount.

4. 3. The plating apparatus according to claim 2, the control device replenishes the replenishment amount of the metal or the metal compound containing the replenishment amount of the metal from the replenishment device to the catholyte a plurality of times; a plating apparatus, wherein, when the total charge amount changes from a first charge amount to a second charge amount, an area of ​​the correction curve is calculated as a value that approximates an area of ​​the correction curve in a section from the first charge amount to the second charge amount by an area of ​​a rectangle.

5. 5. The plating apparatus according to claim 4, the area of ​​the correction curve is calculated as a value obtained by multiplying an average value of the transport number of the hydrogen ion for the first charge amount and the transport number of the hydrogen ion for the second charge amount by a difference between the second charge amount and the first charge amount.

6. 3. The plating apparatus according to claim 2, the calibration curve is an approximation curve calculated using the initial concentration of the metal ions in the anolyte and a ratio of the initial concentration of the metal ions to an initial concentration of an acid, The control device calculates an area of ​​the correction curve using the approximation curve of the correction curve, and calculates the replenishment amount based on the area.

7. 3. The plating apparatus according to claim 2, A storage device for storing the correction curve calculated by simulation is further provided, The control device includes: a plating apparatus that refers to the correction curve in the storage device, calculates an area of ​​the correction curve, and determines the replenishment amount based on the area of ​​the correction curve.

8. 3. The plating apparatus according to claim 2, a storage device for storing data correlating the total charge amount calculated by simulation with the replenishment amount, The control device includes: The plating apparatus determines the replenishment amount by referring to the data in the storage device.

9. 3. The plating apparatus according to claim 2, The control device replenishes the replenishment amount of the metal, or the metal compound containing the replenishment amount of the metal, to the cathode solution each time the total charge amount changes by a predetermined charge amount, based on an area of ​​the correction curve during the change.

10. 3. The plating apparatus according to claim 2, a first concentration sensor for detecting a concentration of metal ions in the anolyte; the control device calculates the correction curve based on a detection value of the concentration of the metal ions detected by the first concentration sensor, and determines the replenishment amount based on an area of ​​the correction curve. Plating equipment.

11. 11. The plating apparatus according to claim 10, a second concentration sensor for detecting a concentration of hydrogen ions in the anolyte; The control device calculates the correction curve based on the detection values ​​of the metal ion concentration and the hydrogen ion concentration detected by the first and second concentration sensors, and determines the replenishment amount based on an area of ​​the correction curve.

12. 3. The plating apparatus according to claim 2, The replenishment amount is calculated by dividing an area of ​​the correction curve by a valence of the metal ion.

13. 13. The plating apparatus according to claim 1, a circulation circuit connected to the cathode chamber and circulating the cathode fluid in the cathode chamber, the circulation circuit having a pump that pumps the cathode fluid; The replenishing device supplies and dissolves the metal or a compound of the metal in the cathode liquid in the flow path of the circulation circuit, The control device controls the pump to circulate the cathode fluid in the cathode chamber through the circulation circuit, and controls the supply device to supply the replenishment amount of the metal or the compound of the metal from the supply device to the cathode fluid in the flow path of the circulation circuit.

14. 13. The plating apparatus according to claim 1, The control device supplies pure water to the anode chamber in response to detecting that the amount of the anolyte has fallen below a predetermined lower limit.

15. 13. The plating apparatus according to claim 1, The control device discharges the anolyte from the anode chamber in response to detecting that the amount of the anolyte has exceeded a predetermined upper limit.

16. 13. The plating apparatus according to claim 1, The anode is in close contact with the lower surface of the cation exchange membrane.

17. 15. The plating apparatus according to claim 14, The plating apparatus further comprises a back plate spaced a predetermined distance from the lower surface of the anode.

18. 13. The plating apparatus according to claim 1, The control device supplies a replenishment amount of the metal, or the metal compound containing the replenishment amount of the metal, which corresponds to the amount of the metal deposited by plating on the substrate, from the replenishment device to the cathode solution after the concentration of the metal ions in the anolyte falls below a predetermined value.

19. 13. The plating apparatus according to claim 1, When the anolyte and the catholyte are newly prepared in the plating tank, the plating tank holds the anolyte and the catholyte having the same composition.

20. 1. A method for plating a substrate, comprising the steps of: A replenishment amount of the metal, which is the amount obtained by subtracting the amount of metal ions of the metal that permeated from the anode chamber to the cathode chamber through a cation exchange membrane that separates the anode chamber and the cathode chamber in the plating tank from the amount of metal deposited on the substrate, or a pre-mixture containing the replenishment amount of the metal. Replenishing the catholyte with a compound of said metal; The plating method, wherein the metal is contained as a cationic metal ion in the anolyte and the catholyte, and is reduced and deposited as a plating film on the substrate.

21. 13. The plating apparatus according to claim 1, The plating apparatus wherein the metal is copper.

22. 21. The plating method according to claim 20, The plating method, wherein the metal is copper.

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