Metal ion supply system for electroplating apparatus and method of supplying metal ion to electroplating apparatus

Abstract

The invention provides a metal ion supply system capable of inhibiting dilution of a plating solution in a plating solution circulation chamber. The present invention is used in an electroplating device, and is provided with an anode chamber, an anode provided in the anode chamber, a cathode chamber, a cathode provided in the cathode chamber, a plating solution circulation chamber disposed between the anode chamber and the cathode chamber, a first diaphragm disposed between the anode chamber and the plating solution circulation chamber, and a second diaphragm disposed between the cathode chamber and the plating solution circulation chamber. The plating solution circulation chamber is provided with an outlet for discharging the plating solution to the plating device and an inlet for receiving the plating solution from the plating device so that the plating solution can be circulated, the diffusion and permeation rate of water of the second diaphragm is greater than the diffusion and permeation rate of water of the first diaphragm, and the anode chamber is filled with an anolyte. The anolyte contains ions of the same metal as the metal contained in the anode, the cathode chamber is filled with a catholyte, and the osmotic pressure molar concentration of the catholyte is higher than the osmotic pressure molar concentration of the plating solution in the plating solution circulation chamber.

Description

TECHNICAL FIELD

[0001] The present application relates to a metal ion supply system for an electroplating device and a method of supplying metal ions to an electroplating device. BACKGROUND

[0002] When Cu, Sn, SnAg alloy, Ni, or the like is plated on the surface of a metal plate, a substrate, or the like, an electroplating device provided with a plating bath that contains a plating solution is used. Metal ions (Cu 2+ , Sn 2+ , or the like) contained in the plating solution are consumed due to plating processing, and therefore metal ions need to be supplied to the plating solution in the plating bath.

[0003] As a device for supplying metal ions to the plating solution in the plating bath, a metal enrichment tank provided with an anode region and a cathode region is disclosed in Patent Literature 1. In Patent Literature 1, the plating solution is circulated between the metal enrichment tank and the plating bath of the electroplating device, and thereby metal ions are supplied to the plating solution in the plating bath.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: U.S. Patent No. 9637836 SUMMARY

[0007] When a metal ion supply system using an electrolytic cell (anode chamber / plating solution circulation chamber / cathode chamber) based on a 3-chamber structure separated by two separators as described in Patent Literature 1 is used, metal ions are sometimes supplied from the anode chamber side to the plating solution in the plating solution circulation chamber. In this case, when metal ions electroosmose from the anode chamber side to the plating solution circulation chamber via the separator, water also moves together. On the other hand, electroosmotic movement of hydrogen ions from the plating solution circulation chamber to the cathode chamber via the separator also occurs, and thus water moves together when hydrogen ions electroosmose.

[0008] The inventors conducted in-depth research on the aforementioned metal ion supply system and found that the movement of water accompanying the electroosmotic flow of metal ions is greater than that accompanying the electroosmotic flow of hydrogen ions, sometimes diluting the plating solution in the plating solution circulation chamber. Normally, in an electroplating apparatus, the concentration of the plating solution is maintained at a constant level by replenishing water equivalent to the amount of plating solution reduced due to evaporation, etc. However, if excessive water is supplied to the plating solution in the plating solution circulation chamber due to the aforementioned difference in water movement, the plating solution becomes diluted. If the diluted plating solution is supplied to the electroplating apparatus, the concentration of the plating solution within the apparatus is slowly diluted, which is therefore undesirable. In particular, to increase the production capacity of the plating apparatus, it is necessary to increase the metal ion supply rate. In this case, the amount of water electroosmotically flowing into the plating solution circulation chamber tends to increase relative to the amount of plating solution evaporation, which becomes a particular problem.

[0009] In view of the above, the present invention provides a metal ion supply system for suppressing the dilution of plating solution in the plating solution circulation chamber as the first objective.

[0010] In addition, when using a metal ion supply system based on a three-chamber electrolytic cell (anode chamber / plating solution circulation chamber / cathode chamber) with two types of diaphragms as described in Patent Document 1, the operation of the electroplating apparatus is sometimes stopped for maintenance or other reasons.

[0011] The inventors have conducted in-depth research on the aforementioned metal ion supply system and discovered that during the shutdown of the electroplating apparatus described above, diffusion may occur between the anode chamber and the plating solution circulation chamber via the diaphragm, leading to cation exchange. Metal ions from the plating solution in the circulation chamber may then mix into the anode chamber. If the ionization tendency of the metal ions mixed into the anode chamber is less than that of the anode, a displacement reaction occurs at the anode surface, and metal from the mixed-in metal ions is deposited. If this metal is deposited on the anode surface, the anode surface becomes passivated, and the electrolysis (electrolysis) of the metal ion supply system is hindered. For example, when using Ag... + When the plating solution contains metal ions and Sn is used as the anode, if the Ag in the plating solution... + When ions are mixed into the anode chamber, Sn has a greater tendency to ionize than Ag. Therefore, the following reaction may occur, resulting in passivation of the anode surface.

[0012] [Chemical Formula 1]

[0013] Sn+2Ag + →Sn 2+ +Ag

[0014] In view of the above, the present invention provides a method for supplying metal ions to suppress passivation of the anode surface caused by metal ions mixed in from the plating solution circulation chamber as a second objective.

[0015] Furthermore, in a metal ion supply system based on a three-chamber electrolytic cell (anode chamber / plating solution circulation chamber / cathode chamber) with two types of diaphragms as described in Patent Document 1, a soluble anode is sometimes provided in the anode chamber, and metal ions are supplied from the soluble anode to the anolyte through electrolysis.

[0016] As electrolysis proceeds, the hydrogen ions (H+) contained in the anolyte within the anode chamber... + The metal ions move through the diaphragm into the plating solution circulation chamber, thus decreasing the hydrogen ion concentration in the anolyte and increasing the pH. If the pH increases, sludge from these metal ions may sometimes form in the anolyte or on the diaphragm adjacent to the anode chamber.

[0017] For example, if the metal contained in the soluble anode is Sn, then Sn... 2+ When supplied to the anolyte, if the pH of the anolyte is greater than a certain value, the following reaction may sometimes occur to produce Sn(OH)2, which belongs to sludge.

[0018] [Chemical Formula 2]

[0019] Sn 2+ +2OH - →Sn(OH)2↓

[0020] *Ksp (solubility product) = 5.45 × 10 -27

[0021] If sludge is generated, the electrolysis reaction is hindered, so it is desirable to suppress sludge production. Such sludge often has low solubility in the neutral region. In order to ensure that metal ions are stably dissolved in the anolyte, the pH of the anolyte in the anode chamber needs to be maintained below a certain value.

[0022] Methods to prevent sludge formation include periodically discharging a portion of the anolyte and adding acids such as MSA (methanesulfonic acid) to the anolyte. However, in these methods, a portion of metal ions (Sn) are also discharged along with the anolyte. 2+ This (etc.) leads to increased costs. Furthermore, it creates the need for managing the anolyte, which is therefore complex.

[0023] Another method to prevent sludge formation is to add an insoluble anode to the anode chamber and control it with a different power source. However, this method increases costs due to the added control using a different power source.

[0024] In view of the above, the present invention provides a metal ion supply system for suppressing the generation of sludge in the anolyte and diaphragm in the anode chamber as a third objective.

[0025] In order to achieve the above-mentioned problems, the inventors conducted in-depth research and found that at least a part of the above-mentioned problems can be solved by the following configuration.

[0026] [1] A metal ion supply system for an electroplating apparatus, comprising:

[0027] Anode chamber,

[0028] The anodes installed in the aforementioned anode chamber,

[0029] Cathode chamber,

[0030] The cathode is installed in the above-mentioned cathode chamber.

[0031] The plating solution circulation chamber configured between the anode chamber and the cathode chamber,

[0032] The first diaphragm disposed between the anode chamber and the plating solution circulation chamber, and

[0033] The second diaphragm is disposed between the cathode chamber and the plating solution circulation chamber.

[0034] The aforementioned plating solution circulation chamber has an outlet for discharging the plating solution to the electroplating apparatus and an inlet for receiving the plating solution from the electroplating apparatus, so that the plating solution can circulate.

[0035] The diffusion rate of water through the second diaphragm is greater than that through the first diaphragm.

[0036] The aforementioned anode chamber is filled with an anolyte containing ions of the same metal as that contained in the aforementioned anode.

[0037] The cathode chamber is filled with cathode electrolyte.

[0038] The cathode electrolyte has a higher osmotic pressure molar concentration than the plating solution in the plating solution circulation chamber.

[0039] [2] According to the metal ion supply system described in [1], the anode is a dissolving anode.

[0040] [3] According to the metal ion supply system described in [1] or [2], wherein the first membrane is a cation exchange membrane and the second membrane is a hydrogen ion selective permeable membrane or a bipolar membrane.

[0041] [4] A method for supplying metal ions to an electroplating apparatus, comprising:

[0042] (i) The process of circulating a plating solution containing metal ions between a plating solution circulation chamber and an electroplating apparatus, and supplying the metal ions to the electroplating apparatus, and

[0043] (ii) Instead of supplying the metal ions to the electroplating apparatus, the plating solution circulation chamber is replaced with a liquid that does not substantially contain at least one of the metal ions.

[0044] [5] The metal ion supply method according to [4] further includes, when switching between the metal ion supply step (i) and the metal ion non-supply step (ii), a step of discharging the plating liquid or a liquid that does not substantially contain at least one of the metal ions in the plating liquid circulation chamber to the outside of the electroplating apparatus.

[0045] [6] The metal ion supply method according to [4] further includes, when switching between the metal ion supply step (i) and the metal ion non-supply step (ii), stopping the operation of the plating solution circulation chamber and discharging the plating solution or liquid that does not substantially contain at least one of the metal ions in the plating solution circulation chamber to the outside of the electroplating apparatus.

[0046] [7] The metal ion supply method according to any one of [4] to [6], wherein the above-mentioned plating solution circulation chamber uses a metal ion supply system disposed between the anode chamber and the cathode chamber.

[0047] [8] The metal ion supply method according to any one of [4] to [6], wherein the metal ion supply system described in [1] is used for supply.

[0048] [9] A metal ion supply system for an electroplating apparatus, comprising:

[0049] The anode chamber contains an anode and is filled with anolyte.

[0050] The cathode chamber contains a cathode and is filled with cathode electrolyte;

[0051] The first plating solution circulation chamber is defined by the first diaphragm and the second diaphragm, and is disposed between the anode chamber and the cathode chamber; and

[0052] One or more stacked modules are disposed between the first plating solution circulation chamber and the cathode, including an anolyte chamber filled with anolyte and a second plating solution circulation chamber defined by the third and fourth diaphragms.

[0053] The third diaphragm is made of the same material as the first diaphragm, and the fourth diaphragm is made of the same material as the second diaphragm.

[0054] The first and second plating solution circulation chambers are respectively equipped with an outlet for discharging the plating solution into the electroplating apparatus and an inlet for receiving the plating solution from the electroplating apparatus, so that the plating solution can circulate.

[0055] The aforementioned anolyte chamber has an outlet for discharging anolyte from the anolyte chamber and an inlet for receiving anolyte into the anolyte chamber, so that the anolyte in the anolyte chamber can be in fluid communication.

[0056]

[10] According to the metal ion supply system described in [9], the first and third diaphragms are cation exchange membranes, and the second and fourth diaphragms are hydrogen ion selective permeable membranes or bipolar membranes.

[0057] According to a first embodiment of the present invention, a metal ion supply system for suppressing the dilution of plating solution in a plating solution circulation chamber can be provided.

[0058] According to a second embodiment of the present invention, a method for supplying metal ions that suppresses passivation of the anode surface due to metal ions mixed in from the plating solution circulation chamber can be provided.

[0059] According to a third embodiment of the present invention, a metal ion supply system for suppressing the generation of metal ions in the anolyte in the anode chamber and the sludge in the diaphragm can be provided. Attached Figure Description

[0060] Figure 1 It is a cross-sectional view showing the overall structure of the metal ion supply system.

[0061] Figure 2 This is an enlarged view of the area surrounding the cathode chamber in a metal ion supply system.

[0062] Figure 3 This is a cross-sectional view showing the structure of an electrolytic cell in a metal ion supply system.

[0063] Figure 4 This is a schematic side view showing the structure of the plating tank.

[0064] Figure 5 This is a diagram showing the overall process of a metal ion supply method.

[0065] Figure 6 It is a cross-sectional view showing the overall structure of the metal ion supply system.

[0066] Figure 7It is a cross-sectional view showing the movement of ions in a metal ion supply system.

[0067] Figure 8 This is a photograph of the 3-chamber electrolytic cell used in the embodiment.

[0068] Figure 9 It is a graph showing the change in the amount (moles) of Cu in the anolyte, plating solution, or catholyte during the test.

[0069] Figure 10 It is a graph showing the changes in the volume (liters) of each liquid in the anolyte, plating solution, or catholyte during the test.

[0070] Figure 11 This is a graph showing the pH changes of the anolyte during the experiment.

[0071] Figure 12 It is a photograph showing the appearance of the cathode after the test.

[0072] Figure 13 This concerns the Cu content when the concentration of the cathode electrolyte (H2SO4) is set to 100 g / L. 2+ A graph showing the change in the concentration (g / L) of H2SO4.

[0073] Figure 14 This is a graph showing the change in the amount (L) of each liquid (anolyte, plating solution, and catholyte) when the concentration of the catholyte is set to 100 g / L.

[0074] Figure 15 This concerns Cu when the concentration of the cathode electrolyte is set to 230 g / L. 2+ A graph showing the change in the concentration (g / L) of H2SO4.

[0075] Figure 16 This is a graph showing the change in the amount (L) of each liquid (anolyte, plating solution, and catholyte) when the concentration of the catholyte is set to 230 g / L.

[0076] Figure 17 This concerns Cu when the concentration of the cathode electrolyte is set to 300 g / L. 2+ A graph showing the change in the concentration (g / L) of H2SO4.

[0077] Figure 18 This is a graph showing the change in the amount (L) of each liquid (anolyte, plating solution, and catholyte) when the concentration of the catholyte is set to 300 g / L.

[0078] Figure 19 It's about the simulation of Cu. 2+A graph showing the change in the concentration (g / L) of H2SO4.

[0079] Figure 20 It is a graph showing the change in the amount (L) of each of the simulated liquids (anolyte, plating solution, and catholyte).

[0080] Figure 21 This is a cross-sectional view of the overall structure of the 3-chamber electrolytic cell 2100 and the plating electrolytic cell (plating tank) 10 used in Experiment Examples 4 to 6.

[0081] Symbol Explanation

[0082] 10… Plating tank (plating electrolytic cell)

[0083] 11…Substrate Holder

[0084] 12… Anode Unit

[0085] 13…Anode Box

[0086] 13a…Septum

[0087] 14… Adjustment plate

[0088] 15…paddle blades

[0089] 16…Outer groove

[0090] W…Substrate

[0091] AN… Anode electrode

[0092] 200… Anode Holder

[0093] 300… Anode Mask

[0094] 700… Circulation Mechanism

[0095] 702… Circulation pipeline

[0096] 704… valve

[0097] 706…pump

[0098] 708…Temperature control device

[0099] 710… filter

[0100] 1100… Anode Chamber

[0101] 1110…framework

[0102] 1120… gasket

[0103] 1200… Plating solution circulation chamber

[0104] 1210…exports

[0105] 1220…Entrance

[0106] 1230… gasket

[0107] 1240…Isolation component

[0108] 1250…Gas Supply Department

[0109] 1260… A liquid supply unit that substantially does not contain at least one of the metal ions.

[0110] Connection parts of 1270, 1280... and waste tank

[0111] V1, V2, V3, V4, V5, V6, V7… valves

[0112] 1300… Cathode Chamber

[0113] 1310…Water Storage Tank

[0114] 1320…framework

[0115] 1330… gasket

[0116] 1400…First diaphragm

[0117] 1500…Second diaphragm

[0118] 1600… Anode

[0119] 1610…Anode housing

[0120] 1700… Cathode

[0121] 1800…ventilation tube

[0122] 1850… gas

[0123] 1900… External power supply

[0124] 2000… Metal ion supply system

[0125] 2100…3-chamber electrolytic cell

[0126] 2200… First plating solution circulation chamber

[0127] 2210…exports

[0128] 2220…Entrance

[0129] 2400…First diaphragm

[0130] 2450…Second diaphragm

[0131] 2500…3rd diaphragm

[0132] 2550…4th diaphragm

[0133] 2800…Layered Modules

[0134] 2810…Anode electrolyte chamber

[0135] 2811…exports

[0136] 2812…Entrance

[0137] 2813, 2814…Piping

[0138] 2820…Second Plating Solution Circulation Chamber

[0139] 2821…exports

[0140] 2822…Entrance

[0141] 2950… Nitrogen

[0142] 3000… Metal ion supply system Detailed Implementation

[0143] The present invention will now be described in detail.

[0144] The description of the constituent elements described below is sometimes based on representative embodiments of the present invention, but the present invention is not limited to the described embodiments.

[0145] It should be noted that in this specification, the numerical range represented by "X~Y" refers to the range encompassed by taking the values ​​represented by X and Y as the lower limit and upper limit, respectively.

[0146] Additionally, in the following descriptions, sometimes the same symbols are used to mark parts with the same function and / or structure, and the descriptions are omitted.

[0147] 1. First Implementation Method

[0148] The metal ion supply system for an electroplating apparatus according to the first embodiment is a metal ion supply system for an electroplating apparatus, comprising:

[0149] Anode chamber,

[0150] The anodes installed in the aforementioned anode chamber,

[0151] Cathode chamber,

[0152] The cathode is installed in the above-mentioned cathode chamber.

[0153] The plating solution circulation chamber configured between the anode chamber and the cathode chamber,

[0154] The first diaphragm disposed between the anode chamber and the plating solution circulation chamber, and

[0155] The second diaphragm is disposed between the cathode chamber and the plating solution circulation chamber.

[0156] The aforementioned plating solution circulation chamber has an outlet for discharging the plating solution to the electroplating apparatus and an inlet for receiving the plating solution from the electroplating apparatus, so that the plating solution can circulate.

[0157] The diffusion rate of water through the second diaphragm is greater than that through the first diaphragm.

[0158] The aforementioned anode chamber is filled with an anolyte containing ions of the same metal as that contained in the aforementioned anode.

[0159] The cathode chamber is filled with cathode electrolyte.

[0160] The cathode electrolyte has a higher osmotic pressure molar concentration than the plating solution in the plating solution circulation chamber.

[0161] The metal ion supply system of this embodiment can suppress the dilution of the plating solution in the plating solution circulation chamber by making the cathode electrolyte have a higher osmotic pressure molar concentration than the plating solution in the plating solution circulation chamber.

[0162] The following describes one aspect of the metal ion supply system of this embodiment.

[0163] Figure 1 It is a cross-sectional view showing the overall structure of the metal ion supply system.

[0164] exist Figure 1The metal ion supply system 2000 includes an anode chamber 1100, a plating solution circulation chamber 1200, and a cathode chamber 1300. A first diaphragm 1400 is disposed between the anode chamber 1100 and the plating solution circulation chamber 1200. A second diaphragm 1500 is disposed between the plating solution circulation chamber 1200 and the cathode chamber 1300. An anode 1600 is disposed in the anode chamber 1100, which is also filled with anolyte. A cathode 1700 is disposed in the cathode chamber 1300, which is also filled with catholyte. The plating solution circulation chamber 1200 includes an outlet 1210 for discharging the plating solution to the electroplating apparatus and an inlet 1220 for receiving the plating solution from the electroplating apparatus. As indicated by the arrows, the plating solution is discharged from the plating solution circulation chamber 1200 to the electroplating apparatus, and also flows from the electroplating apparatus into the plating solution circulation chamber 1200. An external power supply 1900 is connected to the anode 1600 and the cathode 1700. Furthermore, to agitate the anolyte, it is preferable to introduce a gas 1850, such as air, nitrogen, or argon, into the anolyte, for example, through a diffuser 1800. If the anolyte contains easily oxidized metal ions such as Sn(II) ions, then inert gases such as nitrogen or argon are preferably used as the gas 1850. Alternatively, other agitation methods such as impellers or jet nozzles can be used instead of the diffuser 1800 or based on it.

[0165] In the aforementioned metal ion supply system, the diffusion rate of water in the second membrane 1500 is greater than that in the first membrane 1400. For example, it is preferable to use a cation exchange membrane as the first membrane and a hydrogen ion selective permeable membrane or a bipolar membrane as the second membrane.

[0166] exist Figure 1 In the metal ion supply system 2000, the following components are used respectively.

[0167] First diaphragm 1400: Fluorine-based cation exchange membrane; Second diaphragm 1500: Hydrogen ion selective permeability membrane or bipolar membrane; Anode 1600: Cu sphere; Anode electrolyte: CuSO4 solution (partially containing H2SO4) (pH 1.5–3.5); Cathode 1700: Pt / Ti (Pt coated with strip-shaped Ti mesh); Cathode electrolyte: H2SO4 solution.

[0168] If a voltage is applied to the anode 1600 and cathode 1700 by an external power supply 1900, the Cu contained in the anode 1600 will ionize and become Cu. 2+ And it is released into the anolyte. Due to the effect of the potential difference, Cu is released into the anolyte. 2+ The plating solution moves through the cation exchange membrane, i.e., the first diaphragm 1400, into the plating solution circulation chamber 1200. When 1 mole of Cu... 2+ As Cu moves towards the plating solution, n moles of water also move with Cu.2+ And movement (the movement of water caused by electroosmosis as ions move) Figure 1 In the middle, it is represented as "Cu 2+ (H2O) n ”).

[0169] In addition, due to the influence of potential difference, H present in the anolyte + It also moves through the first diaphragm 1400 into the plating solution circulation chamber 1200. In H + As it moves towards the plating solution, the water also moves with H + Movement. Regarding this, in Figure 1 In the metal ion supply system 2000, the pH is adjusted to 1.5–3.5 by ensuring a sufficiently low concentration of sulfuric acid in the anolyte. Therefore, H… + The amount of material moved from the anolyte to the plating solution and the Cu 2+ The amount of movement is extremely small compared to that of water moving with H. + The movement is almost negligible.

[0170] H present in the cathode electrolyte + Electrons are received from cathode 1700, thereby generating hydrogen gas (H2) on the surface of cathode 1700. Due to the effect of electroosmosis, the H2 present in the plating solution... + Hydrogen ions migrate into the cathode electrolyte in the cathode chamber 1300 via a hydrogen ion-selective permeable membrane or a bipolar membrane, i.e., the second diaphragm 1500. 1 mole of H... + As the water moves toward the cathode electrolyte, m moles of water also move with H. + Movement (the movement of water caused by electroosmosis due to the movement of ions) Figure 1 In the middle, it is represented as "H" + (H2O) m ”).

[0171] The second diaphragm has a Cu content of 1500. 2+ Cu has low permeability, therefore Cu 2+ The amount of Cu moving from the plating solution to the cathode electrolyte is extremely small. 2+ It will remain in the plating solution.

[0172] In this embodiment, the cathode electrolyte has a higher osmotic pressure molar concentration (concentration of all solutes) than the plating solution in the plating solution circulation chamber. Therefore, water movement occurs due to diffusion from the plating solution to the cathode electrolyte. Figure 1 In the diagram, it is represented as "H2O" (an arrow extending from the plating solution to the cathode electrolyte).

[0173] The plating solution circulation chamber 1200 is connected to the plating tank of the electroplating apparatus, and the plating solution circulates between the plating solution circulation chamber 1200 and the plating tank. As described above, Cu 2+ It moves from the anolyte chamber, thereby replenishing the plating solution in the plating solution circulation chamber 1200 with Cu as metal ions. 2+ Then, the Cu in the plating solution 2+ The plating solution is transported from the plating bath circulation chamber 1200 to the plating tank and used as raw material for plating treatment. In this way, by operating the metal ion supply system, the electroplating equipment can be operated while supplying metal ions, and plating treatment can be carried out continuously without stopping the electroplating equipment.

[0174] The inventors conducted in-depth research and found that, as in... Figure 1 In the metal ion supply system, under normal operating conditions (liquid temperature 20–40°C, diaphragm current density approximately 3–6 ASD), water flows with Cu... 2+ The amount of electroosmosis (n) from the anolyte to the plating solution varies with water content (H). + The molar ratio (n:m) of the electroosmotic amounts (m) from the plating solution to the cathode electrolyte is approximately 8:3. In this case, the amount of water flowing into the plating solution is greater than the amount flowing out, thus diluting the plating solution. If the plating solution is diluted, the composition of the plating solution supplied to the electroplating apparatus will change, which is therefore undesirable.

[0175] The inventors have discovered that by making the osmotic molar concentration of the cathode electrolyte higher than that of the plating solution in the plating solution circulation chamber 1200, the aforementioned problems can be solved. Normally, osmotic pressure arises due to the difference in osmotic molar concentration, causing water to permeate from the low-concentration side to the high-concentration side. Therefore, by setting the osmotic molar concentrations of the cathode electrolyte and the plating solution as described above, the movement of water caused by diffusion permeation from the plating solution to the cathode electrolyte can be promoted. Thus, by utilizing diffusion permeation to promote water movement, excess water present in the plating solution is released into the cathode electrolyte, thereby suppressing dilution of the plating solution. In this specification, suppressing dilution of the plating solution means delaying or preventing the dilution of the plating solution.

[0176] According to the following Figure 1 The relationship between osmotic pressure and molar concentration in the metal ion supply system is explained in detail.

[0177] The chemical equilibrium of each reaction in the metal ion supply system is summarized in Table 1 below.

[0178] Table 1

[0179]

[0180] If the total CuSO4 concentration is set as Ac and the total H2SO4 concentration is set as As, then the following equations (1) and (2) hold true.

[0181] [Mathematical Expression 1]

[0182] A C =[Cu 2+ ]-(1)

[0183]

[0184] Generally speaking, the ions in the electrolyte achieve electroneutrality, so the following equation (3) holds true.

[0185] [Mathematical Expression 2]

[0186]

[0187] In the above formula (3), [OH - It is almost negligible in acidic solutions.

[0188] Therefore, the osmotic molar concentration (Osm) can be expressed as follows.

[0189] [Mathematical Expression 3]

[0190]

[0191] According to the above formula, if the total CuSO4 concentration, total H2SO4 concentration, and hydrogen ion concentration (pH) in the solution are known, the osmolar concentration can be calculated.

[0192] In equation (3), a hydrogen ion concentration (pH) is required, but for example, if the sulfuric acid concentration in the copper sulfate plating solution exceeds 1 mol / L, the pH is below 0, and sometimes it cannot be measured. In cases where the pH is below 0, [HSO4] is considered... - It is almost non-dissociable, so the following equation can be considered to hold.

[0193] [Mathematical Expression 4]

[0194] Osm = A C +2A

[0195] The components of the metal ion supply system of this embodiment will be described in further detail below.

[0196] (Anode chamber)

[0197] The anode chamber can contain the anode and the anode electrolyte.

[0198] The capacity (size) of the anode chamber is not particularly limited; the optimal size can be selected appropriately based on the required metal ion supply rate (electrolysis rate per unit time) and the size of the anode it houses. The anode chamber is equipped with a liquid level sensor and is preferably connected to a pure water supply line.

[0199] Water can be supplied to the anode chamber via a pure water supply line. By supplying the anode chamber with a pure water amount equivalent to the amount of water flowing out of the plating solution circulation chamber as electroosmotic water during electrolysis through the first diaphragm, and the amount of water reduced due to the evaporation of the anode electrolyte, changes in the concentration of the anode electrolyte can be suppressed.

[0200] (anode)

[0201] The anode is located in the anode chamber. A soluble anode is preferably used. Alternatively, a combination of soluble and non-soluble anodes can be used. By combining soluble and non-soluble anodes, compared to not using a non-soluble anode, the increase in pH of the anolyte caused by electrolysis can be suppressed. Therefore, the decrease in the solubility of the soluble anode can be prevented.

[0202] The metal contained in the anode can be appropriately set according to the type of metal being plated. There are no particular limitations on the metal contained in the anode, but Cu, Sn, Pb, SnPb, Ni, Ag, or Bi are preferred. Among these, Cu is particularly preferred. Furthermore, to improve the solubility of the anode and to suppress undesirable reactions with the plating solution components, an anode with a small amount of impurities may be used. For example, in the case of copper sulfate plating, a phosphorus-containing copper anode is preferred.

[0203] The shape of the anode is not particularly limited, but it can be any shape such as a ball, disk, plate, rod, or cylinder.

[0204] The anode can be composed of one or more components. For example, a plate-shaped (e.g., square plate, round plate) anode can be used, or multiple anode pieces (e.g., spherical, granular, rod-shaped) can be housed in a conductive housing. For example, the anode can be multiple Cu spheres. When using multiple anode pieces, the impact on the electrolytic reaction is small when the anode is consumed and its shape and size change. Furthermore, when multiple anode pieces are housed in a conductive housing, only a new anode equivalent to the amount consumed needs to be added to the housing, without needing to stop the device to replace the anode. The housing material for filling the anode is made of a metal that will not oxidize or dissolve due to the electrode reaction; titanium wire mesh, perforated plates, etc., are preferred. Alternatively, the anode can be housed in an anode bag. By using an anode bag, it is possible to suppress or prevent sludge generated from the anode from mixing into the anode electrolyte. The anode bag can be made of woven or non-woven fabric commonly used for anodes. As the material for the anode bag, chemically resistant resin fibers such as polypropylene and polyvinylidene chloride are preferred.

[0205] (Anodic electrolyte)

[0206] The anolyte, filling the anode chamber, contains ions of the same metal as the metal contained in the anode. For example, when Cu is used as the anode metal, the anolyte may contain Cu ions. 2+ Ions. As metal ions contained in such an anolyte, ions from the aforementioned metals can be used in the anode.

[0207] There are no particular limitations on the metal ions contained in the anolyte, but Cu is preferred. 2+ Sn 2+ Or Ni 2+ Of these, Cu is particularly preferred. 2+ .

[0208] The inventors found through experiments that, under typical electrolysis conditions (liquid temperature 20–40°C, diaphragm current density approximately 3–6 ASD), the amount of water (n moles) electroosminated from the anolyte to the plating solution along with the aforementioned metal ions contained in the anolyte is related to the amount of water osmoticated with H+. + The relationship between the amount of electroosmosis (m moles) from the plating solution to the cathode electrolyte is n > m. This is assumed to be under the condition of normal metal ions, where hydrated water moves along with the metal ions, but H... + In the Grotthuss mechanism (proton hopping mechanism), the charge can also move, so the amount of water moving along with it is relatively small.

[0209] The anolyte can be a solution containing a metal salt. Preferably, the metal salt in this solution is a solution containing the metal salt contained in the plating solution used in combination. For example, when used in combination with a copper sulfate plating solution, a CuSO4 solution can be used as the anolyte, or when using a plating solution with tin methanesulfonate as the main component, a tin methanesulfonate solution can be used as the anolyte. Among these, CuSO4 solution is particularly suitable. A conventional copper sulfate plating solution (VMS) can be used as the anolyte.

[0210] The pH of the anolyte is not particularly limited, but it is preferable to select a pH range that ensures good stability of the metal ions, good solubility of the anode, and high mobility of the metal ions when passing through the first membrane, depending on the type of plating solution and the type of metal ions supplied. For example, when using a copper sulfate plating solution, the pH of the anolyte is preferably 0.5 to 5, more preferably 1 to 4, and most preferably 1.5 to 3.5. By keeping the pH of the anolyte within the above-mentioned range, metal ions can be stably supplied with high current efficiency.

[0211] In this embodiment, gas can be blown into the anolyte (bubbling treatment) and stirred. This can homogenize the concentration distribution of the anolyte, stabilize the electrolysis voltage, and suppress the precipitation of inorganic components.

[0212] The gas is not particularly limited, but non-reactive gases, air, or oxygen can be used. Nitrogen, carbon dioxide, or argon can be used as non-reactive gases. When the anolyte contains easily oxidized metal ions such as divalent Sn ions, a non-reactive gas is preferred. Using a non-reactive gas results in less dissolved oxygen in the anolyte, which inhibits the oxidation of metals in the anolyte and suppresses the formation of Sn(OH)4 as a precipitate.

[0213] When using an anolyte in combination with a copper sulfate plating solution, and the anode contains copper, it is preferable to use an oxygen-containing gas such as air. By using an oxygen-containing gas, the monovalent Cu ions in the anolyte can be oxidized to divalent Cu ions, thereby reducing the concentration of monovalent Cu ions. By reducing the concentration of monovalent Cu ions, the disproportionation reaction of monovalent Cu ions can be used to suppress sludge formation, while also preventing monovalent Cu ions from permeating through the membrane and mixing into the plating solution, thus preventing the plating solution additives from deteriorating.

[0214] The aforementioned gases can be used alone or in combination of two or more. Alternatively, they can replace bubbling or be used in conjunction with other stirring methods such as paddle stirring or jet stirring, or multiple stirring methods can be used in combination.

[0215] (Cathode chamber)

[0216] The cathode chamber can contain the cathode and the cathode electrolyte.

[0217] There is no particular limitation on the capacity (size) of the cathode chamber. The optimal size can be selected appropriately based on the required metal ion supply rate (electrolysis amount per unit time) and the size of the cathode it houses.

[0218] The cathode chamber preferably includes level sensors for detecting three levels of the cathode electrolyte level: the upper limit level (cathode electrolyte upper limit level), the lower limit level (cathode electrolyte lower limit level), and the cathode electrolyte supply level, as well as cathode electrolyte supply and discharge lines linked to them. As electroosmotic water generated during electrolysis and permeate water generated due to the osmotic pressure molar concentration difference with the plating solution are supplied to the cathode electrolyte via the second diaphragm, the cathode electrolyte is diluted, and the level slowly rises. When the level reaches the upper limit level, the cathode electrolyte is discharged from the discharge port to the lower limit level. After discharge, cathode electrolyte is supplied through the cathode electrolyte supply line until the cathode electrolyte supply level is reached, thereby controlling the concentration of the cathode electrolyte within a certain range. It should be noted that flow meters can be installed on the cathode electrolyte supply and discharge lines instead of level sensors, allowing for the supply and discharge of a specified amount of cathode electrolyte. It should be noted that, in the case of a water tank that circulates the cathode electrolyte between the cathode chamber and the cathode chamber, the aforementioned grade sensor and supply / discharge pipelines can also be installed in the water tank.

[0219] (cathode)

[0220] The cathode is located in the cathode chamber. There are no particular limitations on the cathode, but an inactive or insoluble cathode can be used, especially an inactive and insoluble cathode. By using an inactive and insoluble cathode, no components dissolve into the catholyte, thus stabilizing the composition of the catholyte.

[0221] The metal contained in the cathode is not particularly limited, but metals coated with Pt, Ti, Nb, or Pt, or combinations of two or more of them, can be used. Among these, Pt-coated Ti is preferred. When using Pt-coated Ti, the insoluble Pt is coated on the Ti surface, thus becoming an inactive and insoluble cathode. Metal ions do not dissolve from the cathode, and therefore the composition of the cathode electrolyte varies little.

[0222] The shape of the cathode is not particularly limited, but it can be any shape such as a rod, ball, disk, or plate. When the cathode is in the shape of a disk or plate, it can be a perforated metal plate, expanded metal plate, or other shape with multiple through holes. By having multiple through holes, the surface area of ​​the cathode can be increased, and the electrolysis voltage can be reduced even at high current densities.

[0223] A cathode can consist of one or more components.

[0224] (Cathode electrolyte)

[0225] The cathode electrolyte is filled in the cathode chamber.

[0226] The cathode electrolyte is not particularly limited, but it is preferably a solution of an acid containing anion as the main component in the plating solution used in combination. When used in combination with a copper sulfate plating solution, the cathode electrolyte is preferably an H2SO4 solution. By using a solution of an acid containing anion as the main component in the plating solution, even if the cathode electrolyte slightly mixes into the plating solution from the diaphragm or sealing parts, its impact on the plating solution can be minimized.

[0227] The cathode electrolyte preferably does not contain ions of a metal that is substantially the same as the metal contained in the anode. The "metal contained in the anode" mentioned above can be any of the metals described in the anode section. In this specification, "not substantially containing ions of a metal that is substantially the same as the metal contained in the anode" means that the concentration of such metal ions is 0.1 g / L or less.

[0228] In this embodiment, gas can be blown into the cathode electrolyte (bubbling treatment) and stirred. This allows for a more uniform concentration distribution of the cathode electrolyte and a more stable electrolysis voltage. The gas used is not particularly limited and can be the same gas used to stir the anolyte. One or more of the gas can be used alone. Alternatively, other stirring methods such as paddle stirring or jet stirring can be used instead of bubbling, or multiple stirring methods can be used in combination.

[0229] In the metal ion supply system of this embodiment, any one of the following combinations (1) to (3) of anode, anolyte, cathode and catholyte can be used.

[0230] (1) Anode: Cu ball, anode electrolyte: a mixture of copper sulfate and sulfuric acid, cathode: Pt coated Ti mesh, cathode electrolyte: sulfuric acid.

[0231] (2) Anode: Sn particles, anode electrolyte: a mixed solution of tin methanesulfonate and methanesulfonic acid, cathode: Pt coated Ti mesh, cathode electrolyte: methanesulfonic acid solution.

[0232] (3) Anode: Ni ball, anode electrolyte: mixed solution of nickel aminosulfonate and boric acid, cathode: Pt coated Ti mesh, cathode electrolyte: aminosulfonate solution.

[0233] (Plating solution circulation chamber)

[0234] The plating solution circulation chamber is located between the anode chamber and the cathode chamber. The plating solution circulation chamber has an outlet for discharging the plating solution into the electroplating apparatus and an inlet for receiving the plating solution from the electroplating apparatus, allowing the plating solution to circulate. The plating solution circulation chamber can contain the plating solution.

[0235] The plating solution circulation chamber can be defined by the first diaphragm and the second diaphragm, as described later. For example, the plating solution circulation chamber can be an electrolytic cell structure formed by a gasket or separator sandwiched between the first diaphragm and the second diaphragm, which are supported by a frame. Alternatively, the plating solution circulation chamber can be a structure in which an anode chamber with the first diaphragm disposed at its opening and a cathode chamber with the second diaphragm disposed at its opening are arranged at opposite positions of the two diaphragms and maintain a certain distance.

[0236] The capacity of the plating solution circulation chamber is not particularly limited and can be selected according to the required metal ion supply rate (electrolysis volume per unit time). In particular, the plating solution circulation chamber of the above-mentioned electrolytic cell structure can reduce the width of the plating solution circulation chamber to about 1 mm, thereby reducing the capacity of the plating solution circulation chamber, and is therefore preferred.

[0237] In this embodiment, reducing the capacity of the plating solution circulation chamber reduces the amount of plating solution retained within it. This reduces the amount of metal ions mixed into the anode chamber from the plating solution circulation chamber, thereby further suppressing the passivation of the anode surface. For example, reducing the distance between the first and second diaphragms reduces the capacity of the plating solution circulation chamber. In this case, the capacity of the plating solution circulation chamber can be 0.1 to 5 L.

[0238] The ratio of the capacity of the plating solution circulation chamber to the capacity of the anode chamber (capacity of plating solution circulation chamber / capacity of anode chamber) is not particularly limited, but is preferably 0.005 to 0.5, more preferably 0.01 to 0.2, and most preferably 0.01 to 0.1. By keeping the above ratio within the above numerical range, passivation of the anode surface can be further suppressed.

[0239] The flow rate for circulating the plating solution into the plating solution circulation chamber is not particularly limited. The flow rate can be selected to prevent excessive concentration changes in the plating solution within the circulation chamber, based on the required metal ion supply rate (electrolysis rate per unit time). On the other hand, when electrolysis is not performed, to minimize ion diffusion through the first diaphragm, it is preferable to stop circulation or significantly reduce the flow rate. However, when circulation is stopped, compositional changes due to ion diffusion through the first diaphragm may cause crystal formation in the plating solution circulation chamber. Therefore, if circulation is stopped for a certain period or longer, it is preferable to drain the plating solution from the circulation chamber or periodically circulate and replace the plating solution in the circulation chamber.

[0240] (plating solution)

[0241] The metal ion supply system of this embodiment may further include the plating solution contained in the plating solution circulation chamber.

[0242] The composition of the plating solution can be appropriately set according to the metal to be plated in the electroplating apparatus. In the electroplating apparatus, the composition of the plating solution is determined based on the metal to be plated, and the combination of the anode and the anolyte is determined accordingly. The plating solution may contain ions of the same metal as the metal contained in the anode. For example, when Cu is used as the anode metal, the plating solution may contain Cu... 2+ Ions. The metals contained in the aforementioned anode can be used in the aforementioned anode projects.

[0243] The concentration of metal ions in the plating solution that are identical to the metal contained in the anode is not particularly limited, and an appropriate concentration can be selected based on the type of metal being plated, the specifications of the plated film, and the desired uniformity of the plated film. For example, the concentration of metal ions that are identical to the metal contained in the anode can be 20–80 g / L, 30–70 g / L, or 30–65 g / L. By keeping the concentration within the above-mentioned range, excellent uniformity and productivity of the plated film can be achieved.

[0244] There are no particular limitations on the plating solution, but copper sulfate plating solution, Sn alloy plating solution, or Ni sulfamate plating solution can be used. Among these, copper sulfate plating solution is particularly suitable.

[0245] (First diaphragm)

[0246] The first diaphragm is disposed between the anode chamber and the plating solution circulation chamber. The first diaphragm is not particularly limited, but an ion-exchange membrane or a neutral porous membrane can be used. Among these, an ion-exchange membrane is preferred. The aforementioned ion-exchange membrane is not particularly limited, but a cation-exchange membrane is preferred. By using a cation-exchange membrane, metal ions contained in the anolyte in the anode chamber can be transferred to the plating solution circulation chamber. The cation-exchange membrane can be a fluorine-based cation-exchange membrane or a hydrocarbon-based cation-exchange membrane. Among these, a fluorine-based cation-exchange membrane is preferred in terms of superior membrane durability. In particular, since the membrane tends to deteriorate easily when halide ions are present in the anolyte, a fluorine-based cation-exchange membrane is preferred.

[0247] For the aforementioned fluorine-based cation exchange membranes, FORBLUE (registered trademark) Sx-2301 and Sx-1811 (both manufactured by AGC Corporation), Nafion (registered trademark) N424 and N438 (both manufactured by Chemours Corporation) can be used. For hydrocarbon-based cation exchange membranes, commercially available products such as SELEMION (registered trademark) CMVN (manufactured by AGC Corporation) and NEOSEPTA (registered trademark) CSE (manufactured by Astom Corporation) can be used.

[0248] The diffusion rate of water through the first diaphragm is not particularly limited, but is preferably 0.01–1 (mol / h·dm³). 2 ·(mol / l)), more preferably 0.01–0.5(mol / h·dm). 2 The optimal value is 0.01–0.2 (mol / l·dm³). 2 ·(mol / l)).

[0249] (Second diaphragm)

[0250] The second diaphragm is disposed between the cathode chamber and the plating solution circulation chamber. The second diaphragm is not particularly limited, but can be a hydrogen ion-selective permeable membrane, a bipolar membrane, or a monovalent cation-selective permeable membrane. Among these, a hydrogen ion-selective permeable membrane or a bipolar membrane is particularly preferred. By using a hydrogen ion-selective permeable membrane or a bipolar membrane, the intrusion of metal ions in the plating solution into the cathode chamber through the second diaphragm can be inhibited.

[0251] As the hydrogen ion selective permeable membrane mentioned above, commercially available products such as SELEMION (registered trademark) HSFN (manufactured by AGC Engineering Co., Ltd.) can be used. As the bipolar membrane mentioned above, commercially available products such as NEOSEPTA (registered trademark) BP-1EX (manufactured by Astom Co., Ltd.) can be used.

[0252] The diffusion rate of water through the second diaphragm is not particularly limited, but is preferably 0.1–5 mol / h·dm³. 2 ·(mol / l)), more preferably 0.2–3(mol / h·dm 2 The optimal value is 0.5–2 (mol / h·dm³). 2 ·(mol / l)).

[0253] In the metal ion supply system of this embodiment, the first membrane is preferably a cation exchange membrane, and the second membrane is preferably a hydrogen ion selective permeable membrane or a bipolar membrane. By configuring such a combination, metal ions can be supplied to the plating solution with high current efficiency.

[0254] In the metal ion supply system of this embodiment, the diffusion rate of water in the second diaphragm is greater than that in the first diaphragm.

[0255] The difference between the diffusion rate of water in the second diaphragm and the diffusion rate of water in the first diaphragm is not particularly limited, but is preferably greater than 0 and less than 5 (mol / h·dm). 2 ·(mol / l)), more preferably 0.1–3(mol / h·dm 2 The optimal value is 0.2–2 (mol / h·dm³). 2 The ratio of the diffusion rate of water in the second diaphragm to the diffusion rate of water in the first diaphragm (diffusion rate of water in the second diaphragm / diffusion rate of water in the first diaphragm) is not particularly limited, but is preferably greater than 1 and less than 100, more preferably 3 to 50, and most preferably 5 to 30.

[0256] In the metal ion supply system of this embodiment, the cathode electrolyte has a higher osmotic pressure molar concentration than the plating solution in the plating solution circulation chamber.

[0257] By setting the osmotic molar concentrations of the cathode electrolyte and the plating solution as described above, the movement of water generated by diffusion penetration from the plating solution to the cathode electrolyte can be promoted. Thus, by promoting the movement of water generated by diffusion penetration, excess water present in the plating solution is released into the cathode electrolyte, and dilution of the plating solution can be suppressed.

[0258] The osmotic molar concentration of the cathode electrolyte is not particularly limited, but it is preferably 1 to 15 mol / L, more preferably 2 to 10 mol / L, and most preferably 3 to 8 mol / L.

[0259] The osmotic molar concentration of the plating solution in the plating solution circulation chamber is not particularly limited, but it is preferably 0.5 to 10 mol / L, more preferably 1 to 8 mol / L, and most preferably 2 to 5 mol / L.

[0260] The difference between the osmotic pressure molar concentration of the cathode electrolyte and the osmotic pressure molar concentration of the plating solution in the plating solution circulation chamber is not particularly limited, but is preferably 0.1 to 10 mol / L, more preferably 0.2 to 8 mol / L, and most preferably 0.5 to 5 mol / L.

[0261] The ratio of the osmotic molar concentration of the cathode electrolyte to the osmotic molar concentration of the plating solution in the plating solution circulation chamber (osmotic molar concentration of the cathode electrolyte / osmotic molar concentration of the plating solution) is not particularly limited, but is preferably 1.1 to 10, more preferably 1.2 to 5, and most preferably 1.5 to 3.

[0262] (Other components)

[0263] The metal ion supply system of this embodiment can be further equipped with an external power supply connected to the cathode and anode. Preferably, a reverse current prevention mechanism (such as a diode) is provided in the external power supply. By providing a reverse current prevention mechanism, it is possible to prevent metal ions from moving into the anolyte when a reverse current flows during shutdown.

[0264] In this embodiment, the metal ion supply system may further include a water storage tank, allowing the cathode electrolyte to circulate between the water storage tank and the cathode chamber. Additionally, an oxygen-containing gas (such as air) can be blown into the water storage tank (for bubbling treatment). The water storage tank will be described below as an example.

[0265] Figure 2 This is an enlarged view of the area surrounding the cathode chamber in the metal ion supply system. The metal ion supply system includes the cathode chamber 1300, the cathode 1700, and the second diaphragm 1500, etc.

[0266] exist Figure 2 The metal ion supply system shown is equipped with a water storage tank 1310, which allows the cathode electrolyte to circulate between the water storage tank 1310 and the cathode chamber 1300.

[0267] The cathode electrolyte sometimes contains trace amounts of metal ions (Sn) that have migrated from the plating solution circulation chamber via the second diaphragm 1500. 2+ (etc.). These metal ions sometimes deposit on the cathode surface; if such deposition occurs, the electrolysis voltage will increase. If the aforementioned metal ions are oxidized by blowing oxygen-containing gas into the water tank 1310, the oxidized metal ions (Sn...) 4+(e.g., ions) precipitate as hydroxides. The precipitated hydroxides can be removed using a filter. This suppresses the movement of metal ions (Sn) from the aforementioned plating solution circulation chamber. 2+ The deposition of substances (such as ions) on the cathode surface can prevent the rise of the electrolysis voltage mentioned above.

[0268] In the metal ion supply system of this embodiment, the plating solution circulation chamber located between the anode and cathode chambers can have the same structure as the electrolytic cell structure of the electrodialysis apparatus. Specifically, as Figure 3 As shown, the internal space of the gasket 1230 / isolation member 1240, which is sandwiched between the first diaphragm 1400 supported by the frame 1110 and the gasket 1120 and the second diaphragm 1500 supported by the frame 1320 and the gasket 1330, can be used as a plating solution circulation chamber.

[0269] By configuring the structure as described above, the capacity of the plating solution circulation chamber can be minimized (approximately 1 mm in width). As a result, the effects of dilution and loss of the plating solution when it is replaced in the plating solution circulation chamber with a liquid that substantially does not contain at least one of the aforementioned metal ions can be minimized.

[0270] In this embodiment, the plating solution circulation chamber in the metal ion supply system can be the space defined by the first diaphragm and the second diaphragm, each supported by a free frame.

[0271] (Electroplating equipment)

[0272] The metal ion supply system of this embodiment is a system for supplying metal ions to an electroplating apparatus. Hereinafter, one embodiment of this electroplating apparatus will be described.

[0273] (Composition of the plating tank)

[0274] Figure 4This is a schematic side view illustrating the configuration of a plating tank in an electroplating apparatus. During the plating process, the plating tank 10 is equipped with a substrate holder 11 for holding a substrate W, an anode unit 12 for holding an anode electrode AN, an adjusting plate 14, and a blade 15. The plating tank 10 contains a plating solution, in which the substrate W and the anode electrode AN are immersed. The anode unit 12 has an anode holder 200 for holding the anode electrode AN and an anode mask 300 for adjusting the electric field between the anode electrode AN and the substrate W. In one example, the anode unit 12 is housed within an anode box 13. An opening is provided opposite the anode electrode AN in the anode box 13, and a diaphragm 13a is disposed in the opening. The anode mask 300, for example, comprises one or more generally plate-shaped components made of a dielectric material. The adjusting plate 14 has an opening and, like the anode mask 300, adjusts the electric field between itself and the substrate W. In one example, the size of the opening of the adjusting plate 14 is fixed, and adjusting plates with different opening sizes are used interchangeably. In other examples, the opening size of the adjusting plate 14 can be adjusted. The blade 15 stirs the plating solution near the plating surface of the substrate W. The blade 15 can be, for example, a generally rod-shaped component, and can be arranged in the plating tank 10 in a vertical direction. The blade 15 is configured to move horizontally along the plating surface of the substrate W via a drive device (not shown). Alternatively, the blade 15 can be a blade with multiple longitudinal slits provided in a plate-shaped component. It should be noted that, from the viewpoint of plating quality, it is preferable that the relationship is (exposed area or size of the plating surface of the substrate W) > (opening area or size of the adjusting plate) > (opening area or size of the anode mask). In this case, the area or size of the substrate W itself is larger than the area or size of the opening of the adjusting plate. Therefore, it is preferable to set and / or adjust the opening area (or opening size) of the anode mask and the opening area (or opening size) of the adjusting plate to satisfy the above relationship.

[0275] The anode electrode AN is connected to an external power source (not shown) via wiring within the anode holder 200. Additionally, the plating surface of the substrate W is connected to an external power source via wiring within the substrate holder 11. When a voltage is supplied from the external power source between the anode electrode AN and the substrate W, a plating current flows through the path from the external power source, through the anode electrode AN, the plating solution, the seed layer of the plating surface of the substrate W, and back to the external power source. As a result, metal in the plating solution is deposited on the plating surface of the substrate W, and the substrate W is plating processed.

[0276] The plating tank 10 is equipped with a circulation mechanism 700 that circulates the plating solution between the plating tank 10 and the outer tank 16. The circulation mechanism 700 includes a circulation line 702 connecting the outer tank 16, which receives plating solution overflowing from the plating tank 10, and the plating tank 10. In one example, the circulation line 702 is connected to the bottom of both the plating tank 10 and the bottom of the outer tank 16. A valve 704 is provided in the circulation line 702 for opening and closing. The valve 704 can be, for example, a solenoid valve, and can be configured to control the opening and closing of the circulation line 702 via a control unit (not shown). A pump 706 is provided in the circulation line 702, which circulates the plating solution from the outer tank 16 to the plating tank 10 through the circulation line 702. A temperature control device 708 is provided in the circulation line 702 to control the temperature of the plating solution passing through the circulation line 702. For example, a thermometer (not shown) can be installed in the plating tank 10, and the temperature control device 708 can be controlled by the control unit 103 based on the temperature of the plating solution measured by the thermometer. A filter 710 is installed in the circulation line 702 to remove solid substances from the plating solution passing through the circulation line 702.

[0277] The plating solution circulation chamber of the metal ion supply system in this embodiment is connected to... Figure 4 The plating tank 10 shown allows for the replenishment of metal ions to the plating solution used in the plating apparatus. Alternatively, the plating solution circulation chamber of the metal ion supply system in this embodiment is connected to a water tank connected to the plating tank 10, thereby enabling the replenishment of metal ions to the plating solution used in the plating apparatus.

[0278] 2. Second Implementation Method

[0279] A method for supplying metal ions to the electroplating apparatus of the second embodiment includes:

[0280] (i) A process of supplying the electroplating apparatus with the metal ions by circulating a plating solution containing metal ions between the plating solution circulation chamber and the electroplating apparatus, and

[0281] (ii) Instead of supplying the metal ions to the electroplating apparatus, the plating solution circulation chamber is replaced with a liquid that does not substantially contain at least one of the metal ions.

[0282] In step (ii), where no metal ions are supplied, the metal ion supply method of this embodiment can suppress passivation of the anode surface caused by metal ions mixed in from the plating solution circulation chamber by replacing the plating solution in the plating solution circulation chamber with a liquid that does not substantially contain at least one of the aforementioned metal ions.

[0283] The ionization tendency of the metal contained in the anode is greater than that of the metal that can be mixed into the anode chamber from the plating solution circulation chamber. When such a relationship of ionization tendency holds true, the metal mixed into the anode chamber from the plating solution circulation chamber is more likely to precipitate on the anode surface, so the substitution in step (ii) of this embodiment becomes a more effective means.

[0284] The following describes one aspect of the metal ion supply method according to this embodiment.

[0285] Figure 5 This is a diagram showing the overall process of a metal ion supply method. In Figure 5 In this process, a three-chamber electrolytic cell (sequentially comprising an anode chamber 1100, a first diaphragm 1400, a plating solution circulation chamber 1200, a second diaphragm 1500, and a cathode chamber 1300) can be used to circulate the plating solution between the plating solution circulation chamber 1200 and the electroplating apparatus.

[0286] Figure 5 (A) is a diagram showing the electrolysis process using a 3-chamber electrolytic cell (with metal ions supplied). Figure 5 (A) is equivalent to the process of supplying metal ions in process (i) described above. In Figure 5 In (A), valves V1 and V4 are open on the path between the electroplating apparatus and the plating solution circulation chamber 1200 of the 3-chamber electrolytic cell, while valves V2, V3, and V5 to V7 on other paths are closed. Figure 5 In (A), the plating solution flows from the electroplating apparatus to the plating solution circulation chamber 1200 of the 3-chamber electrolytic cell, and then from the plating solution circulation chamber 1200 back to the electroplating apparatus, thus circulating the plating solution. Figure 5 (A) shows the flow direction of the CSU pump and the flow direction of the CSU return.

[0287] Figure 5 (B) is a diagram illustrating the process of discharging the plating solution from the plating solution circulation chamber 1200 after electrolysis is stopped. Figure 5 When moving from (A) to (B), valves V1 and V4 of the path between the electroplating apparatus and the plating solution circulation chamber 1200 are closed. On the other hand, valve V2 between the gas supply unit 1250 and the plating solution circulation chamber 1200, and another valve V5 between the plating solution circulation chamber 1200 and the electroplating apparatus, are open. Figure 5 In (B), gas is supplied from the gas supply unit 1250 to the plating solution circulation chamber 1200, thereby squeezing out the plating solution present in the plating solution circulation chamber 1200 and moving it towards the electroplating apparatus. The plating solution circulation chamber 1200 is filled with gas. Figure 5 In (B), nitrogen is used as the gas mentioned above.

[0288] Figure 5 (C) is a diagram illustrating the process of replacing the plating solution in the plating solution circulation chamber 1200 with a liquid that substantially does not contain at least one of the metal ions present in the plating solution while electrolysis is stopped. Figure 5 (C) is equivalent to the process described above, step (ii), in which metal ions are not supplied. From... Figure 5 When moving from (B) to (C), valve V2 between the gas supply unit 1250 and the plating solution circulation chamber 1200, and other valves V5 between the plating solution circulation chamber 1200 and the electroplating apparatus, are closed. On the other hand, valve V7 between the supply unit 1260 of the liquid that substantially does not contain at least one of the aforementioned metal ions and the plating solution circulation chamber 1200, and valve V3 between the connection portion 1270 of the plating solution circulation chamber 1200 and the waste tank, are open. Figure 5 In (C), a liquid that substantially does not contain at least one of the aforementioned metal ions is supplied to the plating solution circulation chamber 1200, which is filled with the aforementioned liquid, and the previously filled nitrogen gas is discarded. Figure 5 In (C), DIW (ultrapure water) or MSA (methanesulfonic acid) is used as the above liquid.

[0289] Figure 5 (D) is a diagram illustrating the process of standing the plating solution in a state where electrolysis has been stopped and the plating solution circulation chamber 1200 is filled with a liquid that substantially does not contain at least one of the aforementioned metal ions. From... Figure 5 When moving from (C) to (D), valves V1 to V7 on the path extending from the plating solution circulation chamber 1200 are closed. Figure 5 In (D), the plating solution circulation chamber 1200 is filled with a liquid that substantially does not contain at least one of the aforementioned metal ions, thus preventing the aforementioned metal ions from mixing into the anode chamber 1100. Therefore, metal from the aforementioned metal ions will not precipitate on the anode surface, and passivation of the anode surface can be suppressed.

[0290] Figure 5 (E) is an accompanying drawing illustrating the process of discharging a liquid substantially free of at least one of the aforementioned metal ions from the plating solution circulation chamber 1200 while electrolysis is stopped. Figure 5 When moving from (D) to (E), valve V2 between the gas supply unit 1250 and the plating solution circulation chamber 1200, and valve V6 between the plating solution circulation chamber 1200 and the waste tank connection 1280, are open. Figure 5In (E), gas is supplied to the plating solution circulation chamber 1200, thereby squeezing out and discarding the liquid that does not substantially contain at least one of the aforementioned metal ions from the plating solution circulation chamber 1200, which is then filled with gas.

[0291] Figure 5 After step (E), electrolysis in the 3-chamber electrolytic cell can be started again, repeating the above process. Figure 5 The process of (A). And, Figure 2 After step (A), it can be repeated. Figure 2 The processes (B) to (E).

[0292] The components of the metal ion supply method of this embodiment will be described in more detail below.

[0293] (Plating solution circulation chamber)

[0294] A plating solution circulation chamber can be configured between the anode chamber and the cathode chamber. The plating solution circulation chamber can have an outlet for discharging the plating solution into the electroplating apparatus and an inlet for receiving the plating solution from the electroplating apparatus, allowing the plating solution to circulate. The plating solution circulation chamber can contain the plating solution.

[0295] The plating solution circulation chamber can be defined by the first diaphragm and the second diaphragm, which will be described later. For example, the plating solution circulation chamber can be an electrolytic cell structure formed by gaskets or spacers held by the first diaphragm and the second diaphragm supported by a frame.

[0296] The capacity of the plating solution circulation chamber is not particularly limited, and an appropriate capacity can be selected according to the required metal ion supply rate (electrolysis volume per unit time), but it is preferably 0.1 to 50 L, more preferably 0.2 to 20 L, and most preferably 0.2 to 10 L. By keeping the capacity within the above-mentioned range, the amount of plating solution discharged and replaced from the circulation chamber can be reduced, shortening the replacement time. In particular, by arranging the plating solution circulation chamber in the above-described electrolytic cell structure, the width of the plating solution circulation chamber can be reduced to about 1 mm, thereby reducing the capacity of the plating solution circulation chamber.

[0297] In this embodiment, the capacity of the plating solution circulation chamber can be reduced, thus reducing the amount of plating solution retained in the circulation chamber. This reduces the amount of metal ions mixed into the anode chamber from the plating solution circulation chamber, thereby further suppressing the passivation of the anode surface. For example, the capacity of the plating solution circulation chamber can be reduced by decreasing the distance between the first and second diaphragms. In this case, the capacity of the plating solution circulation chamber can be 0.2 to 5 L.

[0298] The ratio of the capacity of the plating solution circulation chamber to the capacity of the anode chamber (capacity of plating solution circulation chamber / capacity of anode chamber) is not particularly limited, but is preferably 0.005 to 0.5, more preferably 0.01 to 0.3, and most preferably 0.02 to 0.2. By keeping the above ratio within the above numerical range, passivation of the anode surface can be further suppressed.

[0299] There is no particular limit to the flow rate of the plating solution when it circulates into the plating solution circulation chamber. The flow rate can be selected to prevent excessive changes in the concentration of the plating solution in the circulation chamber, based on the required metal ion supply rate (electrolysis amount per unit time).

[0300] (A liquid that does not substantially contain at least one of the metal ions)

[0301] The liquid supplied to the electroplating apparatus in step (ii) described above, which substantially does not contain at least one of the aforementioned metal ions, is not particularly limited, but DIW (ultrapure water) or a solution of acid contained in the plating solution is preferred. When using a plating solution containing MSA (MeSO3H, methanesulfonic acid) or a salt of methanesulfonic acid, an MSA solution can be used as the liquid; when using a plating solution containing sulfuric acid or a salt of sulfuric acid, a sulfuric acid solution can be used as the liquid. By using DIW (ultrapure water) or a solution of acid contained in the plating solution as the liquid, the impact of contamination with the plating solution can be reduced.

[0302] When the electroplating apparatus supplies only one type of metal ion, the liquid substantially does not contain that metal ion. When the electroplating apparatus supplies two or more types of metal ions, the liquid may substantially not contain one of the two or more metal ions, or it may substantially not contain all of the two or more metal ions.

[0303] The metal ions supplied to the electroplating apparatus may be those described later, which are metal ions contained in the plating solution.

[0304] In this specification, "substantially free of at least one of the metal ions" means that it does not contain at least one of the aforementioned metal ions, or that the concentration of at least one of the aforementioned metal ions is such that even if the at least one metal ion penetrates into the anode chamber and is deposited on the anode surface through displacement, it will not produce a voltage rise due to passivation. "A liquid substantially free of at least one of the metal ions" can be a liquid in which the concentration of the at least one metal ion is 0.1 g / L or less. Alternatively, the liquid used in step (ii) above may not contain the aforementioned metal ions.

[0305] (Additional steps)

[0306] The metal ion supply method of this embodiment may further include a step of discharging the plating solution or liquid in the plating solution circulation chamber to the outside of the electroplating apparatus when switching between the step of supplying metal ions in step (i) and the step of not supplying metal ions in step (ii). Such a step is equivalent to the above-described... Figure 3 (B) process or Figure 6 The process of (E).

[0307] The aforementioned discharge process can be performed by supplying gas into the plating solution circulation chamber to expel the plating solution or liquid. By using such gas, the discharge of the plating solution or liquid can be carried out efficiently.

[0308] The aforementioned gases are not particularly limited, but examples include nitrogen, argon, air, or combinations of two or more of these. Nitrogen is preferred. By using nitrogen, Sn can be suppressed. 2+ Oxidation of easily oxidized metal ions.

[0309] In the metal ion supply method of this embodiment, a metal ion supply system comprising an anode chamber, a cathode chamber, and the aforementioned plating solution circulation chamber disposed between the anode chamber and the cathode chamber can be used.

[0310] The metal ion supply system described above may be the same as the metal ion supply system described in "1. First Embodiment" or the metal ion supply system described in "3. Third Embodiment" below.

[0311] (Anode chamber)

[0312] The anode chamber can contain the anode and the anode electrolyte.

[0313] The capacity (size) of the anode chamber is not particularly limited; the optimal size can be selected appropriately based on the required metal ion supply rate (electrolysis rate per unit time) and the size of the anode it houses. The anode chamber is equipped with a liquid level sensor and is preferably connected to a pure water supply line.

[0314] Water can be supplied to the anode chamber via a pure water supply line. The amount of pure water that flows out of the plating solution circulation chamber as electroosmotic water during electrolysis through the first diaphragm, equivalent to the amount of water reduced due to the evaporation of the anode electrolyte, is supplied to the anode chamber, thereby suppressing changes in the concentration of the anode electrolyte.

[0315] (anode)

[0316] The anode is located in the anode chamber. A soluble anode is preferably used. Alternatively, a combination of soluble and insoluble anodes can be used. By combining soluble and insoluble anodes, the increase in pH of the anolyte caused by electrolysis can be suppressed compared to the case where an insoluble anode is not used. Therefore, a decrease in the solubility of the anode can be prevented.

[0317] The metal contained in the anode can be appropriately set according to the type of metal being plated. There are no particular limitations on the metal contained in the anode, but Sn, Cu, Pb, SnPb, Ni, Ag, or Bi are preferred. Among these, Sn is particularly preferred.

[0318] The shape of the anode is not particularly limited, but it can be any shape such as a ball, disk, plate, rod, or cylinder.

[0319] The anode can be composed of one or more components. For example, a plate-shaped (e.g., square plate, round plate) anode can be used, or multiple anode pieces (e.g., spherical, granular, rod-shaped) can be housed in a conductive shell. For example, the anode can be multiple Sn spheres or cylinders. When using multiple anode pieces, the impact on the electrolytic reaction is smaller when the anode is consumed and its shape and size change. Furthermore, when multiple anode pieces are housed in a conductive shell, only a new anode equivalent to the amount consumed needs to be added to the shell; there is no need to stop the device to replace the anode. The shell containing the anode is made of a metal that will not oxidize or dissolve due to the electrode reaction; titanium wire mesh, perforated plates, etc., are preferred. Alternatively, the anode can be housed in an anode bag. By using an anode bag, it is possible to suppress or prevent sludge generated from the anode from mixing into the anode electrolyte. The anode bag can be made of woven or non-woven fabric commonly used for anodes. For the anode bag material, resin fibers that are resistant to chemicals, such as polypropylene and polyvinylidene chloride, are preferred.

[0320] (Anodic electrolyte)

[0321] The anolyte fills the anode chamber. The anolyte may contain ions of the same metal as the metal contained in the anode. For example, if Sn is used as the anode metal, the anolyte may contain Sn ions. 2+ Ions. The metals contained in the above-mentioned anode can be used in the above-mentioned anode projects.

[0322] There are no particular limitations on the anolyte, but alkyl sulfonic acid solutions such as MSA solution, sulfuric acid solutions, or aminosulfonic acid solutions can be used. Among these, MSA solution is particularly suitable. When the anolyte contains MSA solution, it may further contain H₂SO₄.

[0323] There are no particular restrictions on the metal ions contained in the anolyte, but Sn can be used. 2+ Cu 2+ or Ni 2+ Among these, Sn is particularly useful. 2+ .

[0324] The pH of the anolyte is not particularly limited, but it is preferable to select a pH range that ensures good stability of the metal ions, good solubility of the anode, and high mobility of the metal ions when passing through the first membrane, depending on the type of plating solution and the type of metal ions supplied. For example, when using a tin plating solution, the pH of the anolyte is preferably 0 to 2, more preferably 0 to 1.5, and most preferably 0 to 1. By keeping the pH of the anolyte within the above-mentioned range, metal ions can be stably supplied with high current efficiency.

[0325] Each step in the method of this embodiment can be performed while the anolyte is filled into the anolyte chamber.

[0326] In this embodiment, gas can be blown into the anolyte (bubbling treatment) and stirred. This can homogenize the concentration distribution of the anolyte, stabilize the electrolysis voltage, and suppress the precipitation of inorganic components.

[0327] The gas is not particularly limited, but non-reactive gases, air, or oxygen can be used. Nitrogen, carbon dioxide, or argon can be used as non-reactive gases. When the anolyte contains easily oxidized metal ions such as divalent Sn ions, a non-reactive gas is preferred. Using a non-reactive gas results in less dissolved oxygen in the anolyte, which inhibits the oxidation of metals in the anolyte and suppresses the formation of Sn(OH)4 as a precipitate. Furthermore, by using a non-reactive gas, Sn in the anolyte can be suppressed. 2+ The reduced concentration decreases the consumption of the anode. The aforementioned gases can be used alone or in combination of two or more. Alternatively, they can replace the aforementioned bubbling or be used with other stirring methods such as paddle stirring or jet stirring, or multiple stirring methods can be used in combination.

[0328] (Cathode chamber)

[0329] The cathode chamber can contain the cathode and the cathode electrolyte.

[0330] There is no particular limitation on the capacity (size) of the cathode chamber. The optimal size can be selected appropriately based on the required metal ion supply rate (electrolysis amount per unit time) and the size of the cathode it houses.

[0331] The cathode chamber preferably includes level sensors for detecting three levels of the cathode electrolyte level: the upper limit level (cathode electrolyte upper limit level), the lower limit level (cathode electrolyte lower limit level), and the cathode electrolyte supply level, as well as cathode electrolyte supply and discharge lines linked to them. As electroosmotic water generated during electrolysis and permeate water generated due to the osmotic pressure molar concentration difference with the plating solution are supplied to the cathode electrolyte via the second diaphragm, the cathode electrolyte is diluted, and the level slowly rises. When the level reaches the upper limit level, the cathode electrolyte is discharged from the discharge port to the lower limit level. After discharge, the cathode electrolyte is supplied again via the cathode electrolyte supply line to reach the cathode electrolyte supply level, thereby controlling the concentration of the cathode electrolyte within a certain range. It should be noted that flow meters can be installed on the cathode electrolyte supply and discharge lines instead of level sensors, allowing for the supply and discharge of a specified amount of cathode electrolyte. It should be noted that, in the case of a water tank that circulates the cathode electrolyte between the cathode chamber and the cathode chamber, the aforementioned grade sensor and supply / discharge pipelines can also be installed in the water tank.

[0332] (cathode)

[0333] The cathode is located in the cathode chamber. There are no particular limitations on the cathode, but an inactive or insoluble cathode can be used, especially an inactive and insoluble cathode. By using an inactive and insoluble cathode, no components dissolve into the catholyte, thus stabilizing the composition of the catholyte.

[0334] The metal contained in the cathode is not particularly limited, but Pt, Ti, Nb, Pt-coated metals, or combinations of two or more of them can be used. Among these, Pt-coated Ti is preferred. When using Pt-coated Ti, the insoluble Pt is coated on the Ti surface, thus becoming an inactive and insoluble cathode. Metal ions will not dissolve from the cathode, and therefore there is no change in the composition of the cathode electrolyte.

[0335] The shape of the cathode is not particularly limited, but it can be any shape such as a rod, ball, disk, or plate. When the cathode is in the shape of a disk or plate, it can be a perforated metal plate, expanded metal plate, or other shape with multiple through holes. By having multiple through holes, the surface area of ​​the cathode can be increased, and the electrolysis voltage can be reduced even at high current densities.

[0336] A cathode can consist of one or more components.

[0337] (Cathode electrolyte)

[0338] The cathode electrolyte is filled in the cathode chamber.

[0339] The cathode electrolyte is not particularly limited, but it is preferably a solution of an anionic acid that is the main component of the plating solution used in combination. When used in combination with a tin methanesulfonate alloy plating solution, an MSA solution is preferred as the cathode electrolyte. By using a solution of anionic acid that is the main component of the plating solution, even if the cathode electrolyte slightly mixes into the plating solution from the diaphragm or seal, the impact on the plating solution can be minimized.

[0340] The cathode electrolyte may substantially be free of ions of the same metal as that contained in the anode. The term "metal contained in the anode" may refer to the metals described above in the anode specifications. In this specification, "substantially free of ions of the same metal as that contained in the anode" means that the concentration of such ions is 0.1 g / L or less.

[0341] In this embodiment, gas can be blown into the cathode electrolyte (bubbling treatment) and stirred. This allows for a more uniform concentration distribution of the cathode electrolyte and a more stable electrolysis voltage. The gas used is not particularly limited and can be the same gas used to stir the anolyte. One or more of the gas can be used alone. Alternatively, other stirring methods such as paddle stirring or jet stirring can be used instead of bubbling, or multiple stirring methods can be used in combination.

[0342] Each step in the method of this embodiment can be performed while the cathode electrolyte is filled into the cathode chamber.

[0343] In this embodiment, any one of the following combinations of anode, anolyte, cathode, and cathode electrolyte (1) to (3) can be used.

[0344] (1) Anode: Sn particles, anolyte: a mixed solution of tin methanesulfonate and MSA, cathode: Pt coated Ti mesh, cathode electrolyte: MSA solution.

[0345] (2) Anode: Cu ball, anode electrolyte: mixed solution of copper sulfate and sulfuric acid, cathode: Pt coated Ti mesh, cathode electrolyte: sulfuric acid solution.

[0346] (3) Anode: Ni ball, anode electrolyte: mixed solution of nickel aminosulfonate and boric acid, cathode: Pt coated Ti mesh, cathode electrolyte: aminosulfonate solution.

[0347] (plating solution)

[0348] The metal ion supply system of this embodiment may further include the plating solution contained in the plating solution circulation chamber.

[0349] The composition of the plating solution can be appropriately set according to the metal being plated in the electroplating apparatus. The composition of the plating solution is determined based on the metal being plated in the electroplating apparatus, and the combination of the anode and the anolyte can be determined accordingly. The plating solution may contain ions of the same metal as the metal contained in the anode. For example, if Sn is used as the anode metal, the plating solution may contain Sn. 2+ Ions. The metals contained in the above-mentioned anode can be used in the above-mentioned anode projects.

[0350] The concentration of metal ions in the plating solution that are identical to the metal contained in the anode is not particularly limited, and an appropriate concentration can be selected based on the type of metal being plated, the specifications of the plated film, and the desired uniformity of the plated film. For example, the concentration of metal ions that are identical to the metal contained in the anode can be 10–200 g / L, 20–150 g / L, or 30–100 g / L. By keeping the concentration within the above-mentioned numerical range, the uniformity of the plated film is excellent.

[0351] There are no particular limitations on the plating solution, but Sn alloy plating solution, copper sulfate plating solution, or Ni sulfamate plating solution can be used. Among these, Sn alloy plating solution is particularly suitable.

[0352] The plating solution circulating between the plating bath circulation chamber and the electroplating apparatus contains metal ions. This metal ion is not particularly limited, but Ag can be cited as an example. + Sn 2+ Cu 2+ Bi 3+ Or combinations of two or more of them. Among these, Ag is particularly useful. + With Sn 2+ The combination of .

[0353] The ionization tendency of the metal contained in the anode can be made greater than that of the metal that can be mixed into the anode chamber from the plating bath circulation chamber. As a combination of metals with such a relationship of ionization tendency, any one of the following combinations (1) to (3) can be used.

[0354] (1) The metal contained in the anode: Sn, and the metal that can be mixed into the anode chamber from the plating solution circulation chamber: Ag.

[0355] (2) The metal contained in the anode: Sn, and the metal that can be mixed into the anode chamber from the plating solution circulation chamber: Cu.

[0356] (3) The metal contained in the anode: Sn, and the metal that can be mixed into the anode chamber from the plating solution circulation chamber: Bi.

[0357] (First diaphragm)

[0358] The first diaphragm is disposed between the anode chamber and the plating solution circulation chamber. The first diaphragm is not particularly limited, but an ion-exchange membrane or a neutral porous membrane can be used. Among these, an ion-exchange membrane is preferred. The aforementioned ion-exchange membrane is not particularly limited, but a cation-exchange membrane is preferred. By using a cation-exchange membrane, metal ions contained in the anolyte in the anode chamber can be transferred to the plating solution circulation chamber. The cation-exchange membrane can be a fluorine-based cation-exchange membrane or a hydrocarbon-based cation-exchange membrane. Among these, a fluorine-based cation-exchange membrane is preferred in terms of superior membrane durability. In particular, since the membrane tends to deteriorate easily when halide ions are present in the anolyte, a fluorine-based cation-exchange membrane is preferred.

[0359] For the aforementioned fluorine-based cation exchange membranes, FORBLUE (registered trademark) Sx-2301 and Sx-1811 (both manufactured by AGC Corporation), Nafion (registered trademark) N424 and N438 (both manufactured by Chemours Corporation) can be used. For hydrocarbon-based cation exchange membranes, commercially available products such as SELEMION (registered trademark) CMVN (manufactured by AGC Corporation) and NEOSEPTA (registered trademark) CSE (manufactured by Astom Corporation) can be used.

[0360] The diffusion rate of water through the first diaphragm is not particularly limited, but is preferably 0.01–1 (mol / h·dm³). 2 ·(mol / l)), more preferably 0.01–0.5(mol / h·dm). 2 The optimal value is 0.01–0.2 (mol / l·dm³). 2 ·(mol / l)).

[0361] (Second diaphragm)

[0362] The second diaphragm is disposed between the cathode chamber and the plating solution circulation chamber. The second diaphragm is not particularly limited, but can be a hydrogen ion-selective permeable membrane, a bipolar membrane, or a monovalent cation-selective permeable membrane. Among these, a hydrogen ion-selective permeable membrane or a bipolar membrane is particularly preferred. By using a hydrogen ion-selective permeable membrane or a bipolar membrane, metal ions in the plating solution can be prevented from permeating through the second diaphragm and entering the cathode chamber.

[0363] As the hydrogen ion selective permeable membrane mentioned above, commercially available products such as SELEMION (registered trademark) HSFN (manufactured by AGC Engineering Co., Ltd.) can be used. As the bipolar membrane mentioned above, commercially available products such as NEOSEPTA (registered trademark) BP-1EX (manufactured by Astom Co., Ltd.) can be used.

[0364] The diffusion rate of water through the second diaphragm is not particularly limited, but is preferably 0.1–5 mol / h·dm³. 2 ·(mol / l)), more preferably 0.2–3(mol / h·dm 2 The optimal value is 0.5–2 (mol / h·dm³). 2 ·(mol / l)).

[0365] In the metal ion supply system, the first membrane is preferably a cation exchange membrane, and the second membrane is preferably a hydrogen ion selective permeable membrane or a bipolar membrane. This combination enables the supply of metal ions to the plating bath with high current efficiency.

[0366] In a metal ion supply system, the diffusion rate of water in the second diaphragm can be greater than that in the first diaphragm.

[0367] The difference between the diffusion rate of water in the second diaphragm and the diffusion rate of water in the first diaphragm is not particularly limited, but is preferably greater than 0 and less than 5 (mol / h·dm). 2 ·(mol / l)), more preferably 0.1–3(mol / h·dm 2 The optimal value is 0.2–2 (mol / h·dm³). 2 The ratio of the diffusion rate of water in the second diaphragm to the diffusion rate of water in the first diaphragm (diffusion rate of water in the second diaphragm / diffusion rate of water in the first diaphragm) is not particularly limited, but is preferably greater than 1 and less than 100, more preferably 3 to 50, and most preferably 5 to 30.

[0368] (Other components)

[0369] The metal ion supply system can further include an external power supply connected to the cathode and anode. Preferably, the external power supply is equipped with a reverse current prevention mechanism (such as a diode). By providing a reverse current prevention mechanism, it is possible to prevent metal ions from moving into the anolyte when a reverse current flows during shutdown.

[0370] In this embodiment, the metal ion supply system may further include a water storage tank, allowing the cathode electrolyte to circulate between the water storage tank and the cathode chamber. Additionally, an oxygen-containing gas (such as air) can be blown into the water storage tank (for bubbling treatment). The water storage tank will be described below as an example.

[0371] Figure 6 This is an enlarged view of the area surrounding the cathode chamber in the metal ion supply system. The metal ion supply system includes the cathode chamber 1300, the cathode 1700, and the second diaphragm 1500, etc.

[0372] exist Figure 7 The metal ion supply system shown is equipped with a water storage tank 1310, which allows the cathode electrolyte to circulate between the water storage tank 1310 and the cathode chamber 1300.

[0373] The cathode electrolyte sometimes contains trace amounts of metal ions (Sn) that have migrated from the plating solution circulation chamber via the second diaphragm 1500. 2+ (etc.). These metal ions sometimes deposit on the cathode surface; if such deposition occurs, the electrolysis voltage will increase. If the aforementioned metal ions are oxidized by blowing oxygen-containing gas into the water tank 1310, the oxidized metal ions (Sn...) 4+ (e.g., ions) precipitate as hydroxides. The precipitated hydroxides can be removed using a filter. This suppresses the movement of metal ions (Sn) from the aforementioned plating solution circulation chamber. 2+ The deposition of substances (such as ions) on the cathode surface can prevent the rise of the electrolysis voltage mentioned above.

[0374] In the metal ion supply system of this embodiment, the plating solution circulation chamber located between the anode and cathode chambers can have the same structure as the electrolytic cell of the electrodialysis apparatus. Specifically, as follows: Figure 6 As shown, the internal space of the gasket 1230 / isolation member 1240, which is sandwiched between the first diaphragm 1400 supported by the frame 1110 and the gasket 1120 and the second diaphragm 1500 supported by the frame 1320 and the gasket 1330, can be used as a plating solution circulation chamber.

[0375] By configuring the structure as described above, the capacity of the plating solution circulation chamber can be minimized (approximately 1 mm in width). As a result, the effects of dilution and loss of the plating solution when it is replaced in the plating solution circulation chamber with a liquid that substantially does not contain at least one of the aforementioned metal ions can be minimized.

[0376] The plating solution circulation chamber in the metal ion supply system can be the space defined by the first diaphragm and the second diaphragm, which are supported by free frames.

[0377] The metal ion supply system is a system for supplying metal ions to the electroplating apparatus. The electroplating apparatus may be the same as the electroplating apparatus described in "1. First Embodiment" above.

[0378] 3. Third Implementation Method

[0379] The metal ion supply system for the electroplating apparatus according to the third embodiment includes:

[0380] The anode chamber contains an anode and is filled with anolyte.

[0381] The cathode chamber contains a cathode and is filled with cathode electrolyte;

[0382] The first plating solution circulation chamber, defined by the first and second diaphragms, is disposed between the anode chamber and the cathode chamber; and

[0383] One or more stacked modules are disposed between the first plating solution circulation chamber and the cathode, including an anolyte chamber filled with anolyte and a second plating solution circulation chamber defined by the third and fourth diaphragms.

[0384] The third diaphragm is made of the same material as the first diaphragm, and the fourth diaphragm is made of the same material as the second diaphragm.

[0385] The first and second plating solution circulation chambers are respectively equipped with an outlet for discharging the plating solution into the electroplating apparatus and an inlet for receiving the plating solution from the electroplating apparatus, so that the plating solution can circulate.

[0386] The aforementioned anolyte chamber has an outlet for discharging anolyte from the anolyte chamber and an inlet for receiving anolyte into the anolyte chamber, so that the anolyte in the aforementioned anolyte chamber can be in fluid communication.

[0387] The metal ion supply system of this embodiment, by having one or more of the above-mentioned stacked modules, can suppress the generation of anolyte in the anode chamber and sludge in the diaphragm.

[0388] The following describes one aspect of the metal ion supply system of this embodiment.

[0389] Figure 7 It is a cross-sectional view showing the overall structure of the metal ion supply system.

[0390] exist Figure 7The metal ion supply system 3000 includes an anode chamber 1100, a first plating solution circulation chamber 2200, a stacked module 2800, and a cathode chamber 1300. The first plating solution circulation chamber 2200 is defined by a first diaphragm 2400 and a second diaphragm 2450. An anode 1600 is disposed in the anode chamber 1100, which is also filled with an anolyte. A cathode 1700 is disposed in the cathode chamber 1300, which is also filled with a cathode electrolyte.

[0391] The stacked module 2800 includes an anolyte chamber 2810 and a second plating solution circulation chamber 2820. The second plating solution circulation chamber 2820 is defined by a third diaphragm 2500 and a fourth diaphragm 2550. The anolyte chamber 2810 is filled with anolyte. The anolyte chamber 2810 has an outlet 2811 for discharging anolyte from the anolyte chamber 2810 and an inlet 2812 for receiving anolyte into the anolyte chamber 2810, allowing fluid communication between the anolyte in the anode chamber 1100 and the anolyte chamber 2810. The anode chamber 1100 and the anolyte chamber 2810 are connected via pipes 2813 and 2814. The anolyte can move from the anolyte chamber 2810 to the anode chamber 1100 via pipe 2813 and from the anode chamber 1100 to the anolyte chamber 2810 via pipe 2814.

[0392] The first plating solution circulation chamber 2200 and the second plating solution circulation chamber 2820 are provided with outlets 2210 and 2821 for discharging plating solution to the electroplating apparatus and inlets 2220 and 2822 for receiving plating solution from the electroplating apparatus, so that the plating solution can be circulated.

[0393] External power supply 1900 (described later) Figure 7 (As shown in the diagram) It is connected to the anode 1600 and the cathode 1700. As indicated by the arrows, the plating solution is discharged from the first plating solution circulation chamber 2200 and the second plating solution circulation chamber 2820 into the electroplating apparatus. Conversely, plating solution flows from the electroplating apparatus into the first plating solution circulation chamber 2200 and the second plating solution circulation chamber 2820. Additionally, nitrogen 2950 is introduced into the anolyte through the vent pipe 1800.

[0394] exist Figure 7 In the metal ion supply system 3000, the first membrane 2400 and the third membrane 2500 use fluorine-based cation exchange membranes, the second membrane 2450 and the fourth membrane 2550 use hydrogen ion selective permeable membranes or bipolar membranes, the anode 1600 uses Sn spheres, and the cathode 1700 uses Pt-coated Ti mesh.

[0395] Figure 6 It is a cross-sectional view showing the movement of ions in a metal ion supply system.

[0396] existFigure 2 In the middle, Sn passing through the cation exchange membrane, i.e., the first membrane 2400 or the third membrane 2500, will... 2+ Let the mobility be t Sn In this specification, mobility refers to the proportion of current carried by a specific ion in the total current when an electric current flows through an electrolyte solution.

[0397] If 1 mol of Sn 2+ Sn dissolves in the anolyte from the anode 1600 via electrolysis (in amounts of 2 Faradays), and then permeates through the first diaphragm 2400 or the third diaphragm 2500. 2+ The mass of the substance is t Sn Therefore, the total of the first diaphragm (2400 mol) and the third diaphragm (2500 mol) is 2t. Sn mol of Sn 2+ Sn migrates from the anolyte to the plating solution. On the other hand, Sn is impermeable to the hydrogen ion-selectively permeable membrane or bipolar membrane, namely the second membrane 2450 and the fourth membrane 2550. 2+ Therefore, Sn in the anolyte 2+ The total change in the amount of matter is (1-2t) Sn )mol.

[0398] Here, t Sn When >0.5, (1-2t) Sn Since ) < 0, Sn in the anolyte increases during electrolysis. 2+ The amount gradually decreases (H) + (Increase). If Sn in the anolyte 2+ As the concentration decreases, then t Sn It also gets smaller, and thus eventually becomes t Sn =0.5, reaching a stable state.

[0399] On the other hand, t Sn When <0.5, (1-2t) Sn Since ) > 0, Sn in the anolyte increases during electrolysis. 2+ The amount gradually increases (H) + (Reduce). If Sn in the anolyte 2+ As concentration increases, t Sn It also gets bigger, and thus eventually becomes t Sn =0.5, reaching a stable state.

[0400] t Sn When = 0.5, (1-2t) Sn Since ) = 0, Sn in the anolyte increases during electrolysis. 2+ The quantity remains unchanged (H) +(And it doesn't change). Additionally, at this point, 1 mol of Sn... 2+ The anolyte is supplied to the plating solution.

[0401] As mentioned above, the anolyte is naturally adjusted to t during electrolysis. Sn The anolyte composition is 0.5. Therefore, anolyte concentration management only requires replenishing the water that is reduced due to electroosmosis, etc., and no other special anolyte concentration management is required.

[0402] Additionally, in t Sn The anolyte composition of 0.5 contains a sufficient concentration of H₂ to dissolve Sn(OH)₂ as sludge. + Therefore, it can inhibit the formation of sludge.

[0403] exist Figure 2 In this process, the metal ions in the anolyte are Sn. 2+ The case of a single cascaded module is given as an example, but the types of metal ions in the anolyte and / or the number of cascaded modules can be changed. For example, when the stability of metal ions in the anolyte is low at rising pH (low solubility of hydroxide ions), the number of cascaded modules can be increased to make the pH of the anolyte in a stable state lower than the pH at which hydroxide ions are deposited, thereby achieving a balance with... Figure 3 The same example can inhibit the formation of sludge.

[0404] The components of the metal ion supply system of this embodiment will be described in more detail below.

[0405] (Anode chamber)

[0406] The anode chamber can contain the anode and the anode electrolyte.

[0407] The capacity (size) of the anode chamber is not particularly limited; the optimal size can be appropriately selected based on the required metal ion supply rate (electrolysis rate per unit time) and the size of the anode it houses. The anode chamber is equipped with a liquid level sensor and is preferably connected to a pure water supply line.

[0408] Water can be supplied to the anode chamber via a pure water supply line. By supplying a pure water amount equivalent to the amount of water flowing out of the plating solution circulation chamber as electroosmotic water during electrolysis and the amount of water reduced due to the evaporation of the anode electrolyte to the anode chamber, it is possible to suppress changes in the concentration of the anode electrolyte.

[0409] (anode)

[0410] The anode is located in the anode chamber. A soluble anode is preferably used. Alternatively, a combination of soluble and non-soluble anodes can be used. By combining soluble and non-soluble anodes, the increase in pH of the anolyte due to electrolysis can be suppressed compared to the case where a non-soluble anode is not used. Therefore, a decrease in the solubility of the anode can be prevented.

[0411] The metal contained in the anode can be appropriately set according to the type of metal being plated. There are no particular limitations on the metal contained in the anode, but Sn, Cu, Pb, SnPb, Ni, Ag, or Bi are preferred. Among these, Sn is particularly preferred.

[0412] The shape of the anode is not particularly limited, but it can be any shape such as a ball, disk, plate, rod, or cylinder.

[0413] The anode can be composed of one or more components. For example, a plate-shaped (e.g., square plate, round plate) anode can be used, or multiple anode pieces (e.g., spherical, granular, rod-shaped) can be housed in a conductive shell. For example, the anode can be multiple Sn spheres or cylinders. When using multiple anode pieces, the impact on the electrolytic reaction is smaller when the anode is consumed and its shape and size change. Furthermore, when multiple anode pieces are housed in a conductive shell, only a new anode equivalent to the amount consumed needs to be added to the shell; there is no need to stop the device to replace the anode. The shell containing the anode can be made of a metal that will not oxidize or dissolve due to electrode reactions; titanium wire mesh or perforated plates are preferred. Alternatively, the anode can be housed in an anode bag. By using an anode bag, it is possible to suppress or prevent sludge generated from the anode from mixing into the anode electrolyte. The anode bag can be made of woven or non-woven fabric commonly used for anodes. For the anode bag material, resin fibers that are resistant to chemicals, such as polypropylene and polyvinylidene chloride, are preferred.

[0414] (Anodic electrolyte)

[0415] The anolyte fills the anode chamber. The anolyte may contain ions of the same metal as the metal contained in the anode. For example, if Sn is used as the anode metal, the anolyte may contain Sn ions. 2+ Ions. The metals contained in the above-mentioned anode can be used in the above-mentioned anode projects.

[0416] There are no particular limitations on the anolyte, but alkyl sulfonic acid solutions such as MSA solution, sulfuric acid solutions, or aminosulfonic acid solutions can be used. Among these, MSA solution is particularly suitable. When the anolyte contains MSA solution, it may further contain H₂SO₄.

[0417] There are no particular restrictions on the metal ions contained in the anolyte, but Sn can be used. 2+ Cu 2+ Or Ni 2+ Among these, Sn is particularly useful. 2+ .

[0418] The pH of the anolyte is not particularly limited, but it is preferable to select a pH range that ensures good stability of the metal ions, good solubility of the anode, and high mobility of the metal ions when passing through the first membrane, depending on the type of plating solution and the type of metal ions supplied. For example, when using a tin plating solution, the pH of the anolyte is preferably 0 to 2, more preferably 0 to 1.5, and most preferably 0 to 1. By keeping the pH of the anolyte within the above-mentioned range, metal ions can be stably supplied with high current efficiency.

[0419] In this embodiment, gas can be blown into the anolyte (bubbling treatment) and stirred. This can homogenize the concentration distribution of the anolyte, stabilize the electrolysis voltage, and suppress the precipitation of inorganic components.

[0420] The gas is not particularly limited, but non-reactive gases, air, or oxygen can be used. Nitrogen, carbon dioxide, or argon can be used as non-reactive gases. When the anolyte contains easily oxidized metal ions such as divalent Sn ions, a non-reactive gas is preferred. Using a non-reactive gas results in less dissolved oxygen in the anolyte, which inhibits the oxidation of metals in the anolyte and suppresses the formation of Sn(OH)4 as a precipitate. Furthermore, by using a non-reactive gas, Sn in the anolyte can be suppressed. 2+ The reduced concentration decreases the consumption of the anode. The aforementioned gases can be used alone or in combination of two or more. Alternatively, they can replace bubbling or be used with other stirring methods such as paddle stirring or jet stirring, or multiple stirring methods can be used in combination. These stirring methods can be installed in the anode chamber and / or the anode electrolyte chamber.

[0421] (Cathode chamber)

[0422] The cathode chamber can contain the cathode and the cathode electrolyte.

[0423] There is no particular limitation on the capacity (size) of the cathode chamber. The optimal size can be selected appropriately based on the required metal ion supply rate (electrolysis amount per unit time) and the size of the cathode to be housed.

[0424] Preferably, the cathode chamber is equipped with three level sensors for detecting the upper limit level (upper limit level) of the cathode electrolyte, the lower limit level (lower limit level) of the cathode electrolyte, and the cathode electrolyte supply level, as well as cathode electrolyte supply lines and discharge lines linked to them. Electrolyte generated during electrolysis and permeate generated due to the osmotic pressure molar concentration difference with the plating solution are supplied to the cathode electrolyte via a second diaphragm, thus diluting the cathode electrolyte and causing the level to rise slowly. When the level reaches the upper limit level, the cathode electrolyte is discharged from the discharge port to the lower limit level. After discharge, the cathode electrolyte is supplied through the cathode electrolyte supply line to reach the cathode electrolyte supply level, thereby controlling the concentration of the cathode electrolyte within a certain range. It should be noted that flow meters can be installed on the cathode electrolyte supply and discharge lines instead of level sensors, allowing for the supply and discharge of a specified amount of cathode electrolyte. It should be noted that, in the case of a water tank that circulates the cathode electrolyte between the cathode chamber and the cathode chamber, the aforementioned grade sensor and supply / discharge pipelines can also be installed in the water tank.

[0425] (cathode)

[0426] The cathode is located in the cathode chamber. There are no particular limitations on the cathode, but an inactive or insoluble cathode can be used, especially an inactive and insoluble cathode. By using an inactive and insoluble cathode, no components dissolve into the catholyte, thus stabilizing the composition of the catholyte.

[0427] The metal contained in the cathode is not particularly limited, but Pt, Ti, Nb, Pt-coated metals, or combinations of two or more of them can be used. Among these, Pt-coated Ti is preferred. When using Pt-coated Ti, the insoluble Pt is coated on the Ti surface, thus becoming an inactive and insoluble cathode. Metal ions will not dissolve from the cathode, and therefore there is no change in the composition of the cathode electrolyte.

[0428] The shape of the cathode is not particularly limited, but it can be any shape such as a rod, ball, disk, or plate. When the cathode is in the shape of a disk or plate, it can be a perforated metal plate, expanded metal plate, or other shape with multiple through holes. By designing it with multiple through holes, the surface area of ​​the cathode can be increased, and the electrolysis voltage can be reduced even at high current densities.

[0429] The cathode can be composed of one or more components.

[0430] (Cathode electrolyte)

[0431] The cathode electrolyte is filled in the cathode chamber.

[0432] The cathode electrolyte is not particularly limited, but it is preferably a solution of an anionic acid that is the main component of the plating solution used in combination. When used in combination with a tin methanesulfonate alloy plating solution, the cathode electrolyte is preferably an MSA solution. By using a solution of anionic acid that is the main component of the plating solution, even if the cathode electrolyte slightly mixes into the plating solution from the diaphragm or sealing parts, the impact on the plating solution can be minimized.

[0433] The cathode electrolyte may substantially be free of ions of the same metal as that contained in the anode. The term "metal contained in the anode" may refer to the metals described above in the anode specifications. In this specification, "substantially free of ions of the same metal as that contained in the anode" means that the concentration of such ions is 0.1 g / L or less.

[0434] In this embodiment, gas can be blown into the cathode electrolyte (bubbling treatment) and stirred. This allows for a more uniform concentration distribution of the cathode electrolyte and a more stable electrolysis voltage. The gas used is not particularly limited and can be the same gas used to stir the anolyte. One or more of the gas can be used alone. Alternatively, other stirring methods such as paddle stirring or jet stirring can be used instead of bubbling, or multiple stirring methods can be used in combination.

[0435] In this embodiment, any one of the following combinations of anode, anolyte, cathode, and cathode electrolyte (1) to (3) can be used.

[0436] (1) Anode: Sn particles, anolyte: a mixed solution of tin methanesulfonate and MSA, cathode: Pt coated Ti mesh, cathode electrolyte: MSA solution.

[0437] (2) Anode: Cu ball, anode electrolyte: mixed solution of copper sulfate and sulfuric acid, cathode: Pt coated Ti mesh, cathode electrolyte: sulfuric acid solution.

[0438] (3) Anode: Ni ball, anode electrolyte: mixed solution of nickel aminosulfonate and boric acid, cathode: Pt coated Ti mesh, cathode electrolyte: aminosulfonate solution.

[0439] (First and Second Plating Solution Circulation Chambers)

[0440] The first and second plating solution circulation chambers are equipped with an outlet for discharging plating solution into the electroplating apparatus and an inlet for receiving plating solution from the electroplating apparatus, so that the plating solution can circulate. The first and second plating solution circulation chambers can contain plating solution.

[0441] The first plating solution circulation chamber is defined by the first diaphragm and the second diaphragm, which will be described later. For example, the first plating solution circulation chamber may be an electrolytic cell structure formed by gaskets or spacers held between the first diaphragm and the second diaphragm, which are supported by a frame.

[0442] The second plating solution circulation chamber is defined by the third and fourth diaphragms, which will be described later. For example, the second plating solution circulation chamber may be an electrolytic cell structure formed by gaskets or spacers held by the third and fourth diaphragms supported by a frame.

[0443] The capacity of the first and / or second plating solution circulation chambers is not particularly limited, and an appropriate capacity can be selected according to the required metal ion supply rate (electrolysis rate per unit time). In particular, the first and / or second plating solution circulation chambers of the above-described electrolytic cell structure can reduce the width of the plating solution circulation chamber to about 1 mm, thereby reducing the capacity of the plating solution circulation chamber, and are therefore preferred.

[0444] In this embodiment, the capacity of the first and / or second plating solution circulation chambers can be reduced, thereby reducing the amount of plating solution retained in the first and / or second plating solution circulation chambers. This reduces the amount of metal ions mixed into the anode chamber from the first and / or second plating solution circulation chambers, resulting in suppression of the aforementioned passivation of the anode surface. For example, by reducing the distance between the first and second diaphragms and / or the distance between the third and fourth diaphragms, the capacity of the first and / or second plating solution circulation chambers can be reduced.

[0445] The ratio of the capacity of the plating solution circulation chamber (the sum of the capacities of the first and second plating solution circulation chambers) to the capacity of the anode chamber (capacity of the plating solution circulation chamber / capacity of the anode chamber) is not particularly limited, but is preferably 0.005 to 0.5, more preferably 0.01 to 0.2, and most preferably 0.01 to 0.1. By keeping the above ratio within the above-mentioned numerical range, passivation of the anode surface can be suppressed.

[0446] The flow rate for circulating the plating solution to the first and / or second plating solution circulation chambers is not particularly limited. The flow rate can be selected based on the required metal ion supply rate (electrolysis rate per unit time) to prevent excessive changes in the concentration of the plating solution in the circulation chambers. On the other hand, to minimize ion diffusion through the first and third membranes when electrolysis is not performed, it is preferable to stop circulation or keep the flow rate sufficiently low. When circulation is stopped, compositional changes due to ion diffusion through the first and third membranes may cause crystal formation in the first and / or second plating solution circulation chambers. Therefore, if circulation is stopped for a certain period or longer, it is preferable to drain the plating solution from the first and / or second plating solution circulation chambers or periodically circulate and replace the plating solution in the first and second plating solution circulation chambers.

[0447] (plating solution)

[0448] The metal ion supply system of this embodiment may further include the plating solution contained in the first plating solution circulation chamber and / or the second plating solution circulation chamber.

[0449] The composition of the plating solution can be appropriately set according to the metal being plated in the electroplating apparatus. The composition of the plating solution is determined based on the metal being plated in the electroplating apparatus, and the combination of the anode and the anolyte can be determined accordingly. The plating solution may contain ions of the same metal as the metal contained in the anode. For example, if Sn is used as the anode metal, the plating solution may contain Sn. 2+ Ions. The metals contained in the above-mentioned anode can be used in the above-mentioned anode projects.

[0450] The concentration of metal ions in the plating solution that are identical to the metal contained in the anode is not particularly limited, and an appropriate concentration can be selected based on the type of metal being plated, the specifications of the plated film, and the desired uniformity of the plated film. For example, the concentration of metal ions that are identical to the metal contained in the anode can be 10–200 g / L, 20–150 g / L, or 30–100 g / L. By keeping the concentration within the above-mentioned numerical range, the uniformity of the plated film is excellent.

[0451] There are no particular limitations on the plating solution, but Sn alloy plating solution, copper sulfate plating solution, or Ni sulfamate plating solution can be used. Among these, Sn alloy plating solution is particularly suitable.

[0452] The plating solution circulating between the first and second plating solution circulation chambers and between the electroplating apparatus may contain metal ions. There are no particular limitations on the metal ions, but Ag can be cited as an example. + Sn2+ Cu 2+ Bi 3+ Or combinations of two or more of them. Among these, Ag can be used in particular. + With Sn 2+ The combination of .

[0453] (Separator 1 and Separator 3)

[0454] In this embodiment, the first diaphragm may be made of the same material as the third diaphragm.

[0455] The first and / or third membranes are not particularly limited, but ion exchange membranes or neutral porous membranes can be used. Among these, ion exchange membranes are preferred. The aforementioned ion exchange membranes are not particularly limited, but cation exchange membranes are preferred. By using a cation exchange membrane, metal ions contained in the anolyte in the anode chamber can be transferred to the plating solution circulation chamber. Fluorine-based or hydrocarbon-based cation exchange membranes can be used. Among these, fluorine-based cation exchange membranes are preferred in terms of superior membrane durability. In particular, the membrane tends to deteriorate easily when the anolyte contains halide ions, therefore, fluorine-based cation exchange membranes are preferred.

[0456] For the aforementioned fluorine-based cation exchange membranes, FORBLUE (registered trademark) Sx-2301 and Sx-1811 (both manufactured by AGC Corporation), Nafion (registered trademark) N424 and N438 (both manufactured by Chemours Corporation) can be used. For hydrocarbon-based cation exchange membranes, commercially available products such as SELEMION (registered trademark) CMVN (manufactured by AGC Corporation) and NEOSEPTA (registered trademark) CSE (manufactured by Astom Corporation) can be used.

[0457] The diffusion rate of water through the first and / or third membranes is not particularly limited, but is preferably 0.01 to 1 (mol / h·dm³). 2 ·(mol / l)), more preferably 0.01–0.5(mol / h·dm). 2 The optimal value is 0.01–0.2 (mol / l·dm³). 2 ·(mol / l)).

[0458] (Second and fourth septa)

[0459] In this embodiment, the second diaphragm may be made of the same material as the fourth diaphragm.

[0460] The second and / or fourth membranes are not particularly limited, but can be hydrogen ion-selective permeable membranes, bipolar membranes, or monovalent cation-selective permeable membranes. Among these, hydrogen ion-selective permeable membranes or bipolar membranes are particularly preferred. By using hydrogen ion-selective permeable membranes or bipolar membranes, it is possible to prevent metal ions in the plating solution from permeating through the second and fourth membranes and entering the cathode chamber.

[0461] As the hydrogen ion selective permeable membrane mentioned above, commercially available products such as SELEMION (registered trademark) HSFN (manufactured by AGC Engineering Co., Ltd.) can be used. As the bipolar membrane mentioned above, commercially available products such as NEOSEPTA (registered trademark) BP-1EX (manufactured by Astom Co., Ltd.) can be used.

[0462] The diffusion rate of water through the second and / or fourth diaphragm is not particularly limited, but is preferably 0.1–5 mol / h·dm³. 2 The optimal value is 0.2–3 (mol / h·dm³). 2 ·(mol / l)).

[0463] In the metal ion supply system, the first and third membranes are preferably cation exchange membranes, and the second and fourth membranes are preferably hydrogen ion selective permeable membranes or bipolar membranes. This combination enables the supply of metal ions to the plating bath with high current efficiency.

[0464] In a metal ion supply system, the diffusion and permeation rates of water in the second and fourth diaphragms can be greater than those in the first and third diaphragms.

[0465] The difference between the water diffusion rate of the second and fourth diaphragms and the water diffusion rate of the first and third diaphragms is not particularly limited, but is preferably greater than 0 and less than 5 (mol / h·dm). 2 ·(mol / l)), more preferably 0.1–3(mol / h·dm 2 The optimal value is 0.2–2 (mol / h·dm³). 2 The ratio of the water diffusion rate of the second and fourth diaphragms to the water diffusion rate of the first and third diaphragms (water diffusion rate of the second and fourth diaphragms / water diffusion rate of the first and third diaphragms) is not particularly limited, but is preferably greater than 1 and less than 100, more preferably 3 to 50, and most preferably 5 to 30.

[0466] (One or more stacked modules)

[0467] One or more stacked modules are configured between the first plating solution circulation chamber and the cathode.

[0468] Each of the more than one stacked modules includes an anolyte chamber filled with anolyte and a second plating solution circulation chamber defined by a third diaphragm and a fourth diaphragm.

[0469] One or more stacked modules are sufficient. The number of stacked modules is not particularly limited, but is preferably 1 to 5, more preferably 1 to 3, and most preferably 1 to 2. By keeping the number of stacked modules within the above-mentioned range, the structure is not overly complex, the area of ​​the diaphragm used is minimized, and sludge formation in the anolyte is suppressed. Figure 3 and 7 In the example, there is one stacked module.

[0470] (Anode electrolyte chamber)

[0471] The anolyte chamber can contain the anolyte.

[0472] There is no particular limit to the capacity of the anolyte chamber.

[0473] The anolyte chamber may not contain an anode.

[0474] The anolyte filling the anolyte chamber can be the same as the anolyte filling the aforementioned anode chamber. Preferably, the anolyte chamber is connected to the anode chamber via piping, a circulation pump, etc., to allow the anolyte to circulate. The anolyte circulates between the anode chamber and the anolyte chamber, and the dissolved metal ions can be supplied from the anode to the anolyte chamber, stabilizing the composition of the anolyte within the anolyte chamber while simultaneously agitating it.

[0475] There is no particular limitation on the flow rate of the anolyte circulating between the anode chamber and the anolyte chamber. The flow rate should be selected so that the concentration change of the plating solution in the anolyte chamber does not become too large, based on the required metal ion supply rate (electrolysis amount per unit time). On the other hand, in order to minimize the diffusion of ions through the first diaphragm when electrolysis is not taking place, it is preferable to stop the circulation or make the flow rate sufficiently small.

[0476] (Other components)

[0477] The metal ion supply system can further include an external power supply connected to the cathode and anode. Preferably, a reverse current prevention mechanism (such as a diode) is provided in the external power supply. By providing a reverse current prevention mechanism, it is possible to prevent metal ions from moving into the anolyte when a reverse current flows during shutdown.

[0478] In this embodiment, the metal ion supply system may further include a water tank for circulating the cathode electrolyte between itself and the cathode chamber. Additionally, an oxygen-containing gas (such as air) may be blown into the water tank (for bubbling treatment). The water tank will be described below as an example.

[0479] Figure 8 This is an enlarged view of the area surrounding the cathode chamber in the metal ion supply system. The metal ion supply system includes the cathode chamber 1300, the cathode 1700, and the fourth diaphragm 2550, etc.

[0480] exist Figures 9-12 The metal ion supply system shown includes a water storage tank 1310, which allows the cathode electrolyte to circulate between the water storage tank 1310 and the cathode chamber 1300.

[0481] The cathode electrolyte sometimes contains trace amounts of metal ions (Sn) that have migrated from the plating solution circulation chamber via the fourth diaphragm 2550. 2+ (etc.). These metal ions sometimes deposit on the cathode surface; if such deposition occurs, the electrolysis voltage will rise. The aforementioned metal ions are oxidized by blowing oxygen-containing gas into the water tank 1310, forming oxidized metal ions (Sn). 4+ The oxidized metal ions precipitate as hydroxides, which can then be removed by a filter. This suppresses the movement of metal ions (Sn) from the plating solution circulation chamber. 2+ The deposition of substances (such as ions) on the cathode surface can prevent the rise of the electrolysis voltage mentioned above.

[0482] In the metal ion supply system of this embodiment, the first plating solution circulation chamber and / or the second plating solution circulation chamber, located between the anode chamber and the cathode chamber, can have the same structure as the electrolytic cell of the electrodialysis apparatus. Specifically, as follows... Figure 9 As shown, the internal space of the gasket 1230 / isolation member 1240, which is sandwiched between the first diaphragm 1400 supported by the frame 1110 and the gasket 1120 and the second diaphragm 1500 supported by the frame 1320 and the gasket 1330, can be used as the first plating solution circulation chamber.

[0483] exist Figure 10 The diagram shows a first diaphragm 1400 and a second diaphragm 1500, but these can be replaced by a third diaphragm and a fourth diaphragm, respectively. In this case, the internal space of the gasket 1230 / isolation member 1240, which is sandwiched between the third diaphragm supported by the frame 1110 and the gasket 1120 and the fourth diaphragm supported by the frame 1320 and the gasket 1330, can be used as a second plating solution circulation chamber.

[0484] By configuring the structure as described above, the capacity of the first and / or second plating solution circulation chambers can be minimized (approximately 1 mm in width). As a result, the effects of dilution and loss of the plating solution when it is replaced in the plating solution circulation chamber with a liquid that substantially does not contain at least one of the metal ions described later can be minimized.

[0485] In this embodiment, the first plating solution circulation chamber in the metal ion supply system can be a space defined by a first diaphragm and a second diaphragm supported by a frame, respectively. Furthermore, the second plating solution circulation chamber can be a space defined by a third diaphragm and a fourth diaphragm supported by a frame, respectively.

[0486] In the metal ion supply system of this embodiment (the third embodiment), a method for supplying metal ions to the electroplating apparatus, including a step (i) of supplying metal ions as in the second embodiment and a step (ii) of not supplying metal ions, can be applied. In this case, a first plating solution circulation chamber and a second plating solution circulation chamber can be used as plating solution circulation chambers.

[0487] As described above, in the process (ii) where no metal ions are supplied, by replacing the plating solution in the first and second plating solution circulation chambers with a liquid that substantially does not contain at least one of the metal ions supplied to the electroplating apparatus, passivation of the anode surface caused by metal ions mixed in from the first and second plating solution circulation chambers can also be suppressed in the metal ion supply system of this embodiment (third embodiment).

[0488] The metal ion supply system is a system for supplying metal ions to the electroplating apparatus. The electroplating apparatus may be the same as the electroplating apparatus described in "1. First Embodiment" above.

[0489] For the embodiments described in 1 to 3 above, two or more of them can be combined.

[0490] Example

[0491] The present invention will now be described with reference to embodiments, but the present invention is not limited thereto.

[0492] The test examples 1 to 6 described later are test examples corresponding to the first embodiment described above.

[0493] [Experimental Example 1]

[0494] To confirm the metal ion (Cu) supply system using a 3-chamber electrolytic cell (sequentially comprising an anode chamber, a first diaphragm, a plating solution circulation chamber, a second diaphragm, and a cathode chamber) in a metal ion supply system... 2+ The following study was conducted on the supply performance of ).

[0495] Voltage stability during continuous electrolysis

[0496] pH changes during continuous electrolysis and non-electrolysis

[0497] • Concentration changes of inorganic components during continuous electrolysis and non-electrolysis

[0498] The three-chamber electrolytic cell used is shown in... Figure 11 In addition, the electrolytes used (cathode electrolyte, plating solution, anolyte), electrodes and diaphragms, electrolysis conditions, and evaluations are shown in Table 2 below.

[0499] In Test Example 1, the osmotic molar concentration of the plating solution and the osmotic molar concentration of the cathode electrolyte were not adjusted. Test Example 1 is equivalent to the comparative example of the first embodiment described above. At the start of the test, the osmotic molar concentration of the plating solution was approximately 3.4 mol / L, and the osmotic molar concentration of the cathode electrolyte was approximately 2.1 mol / L.

[0500] Table 2

[0501]

[0502] *1: The numbers in parentheses after VMS refer to the concentrations of copper (g / L), sulfuric acid (g / L), and chlorine (mg / L), respectively.

[0503] For example, in the case of VMS (0-100-0), it means copper: 0 g / L, sulfuric acid: 100 g / L, chlorine: 0 mg / L.

[0504] *2: Pt coated Ti mesh strips

[0505] *3: Made by Mitsubishi Materials Co., Ltd.

[0506] *4: Lath-shaped titanium anode basket (insoluble electrode)

[0507] *5: Current density based on diaphragm area

[0508] *6: Electrolysis-free

[0509] *7: Use T4 (4mm thick blades)

[0510] *8: QL-10 analytical device (manufactured by ECI Technology Inc.)

[0511] *9: UV-2600 spectrophotometer (manufactured by Shimadzu Corporation)

[0512] In addition, details of the measurement methods in the "Evaluation" section of Table 2 above are shown below. [Anode and cathode weight measurements before and after the test]

[0513] After the electrolysis test, the anode and cathode were removed from the test electrolytic cell, and their weights after washing and drying were measured using an electronic balance. The initial weights of the anode and cathode before the test were calculated, and their weights after the test were determined separately.

[0514] The difference in weight after the change is taken as the weight change.

[0515] [Changes in the volume of anolyte, plating solution, and catholyte before and after the experiment]

[0516] To the greatest extent possible, recover the anolyte, plating solution, and catholyte from the test electrolytic cell after the electrolysis test, and use a graduated cylinder to measure their respective volumes.

[0517] [Liquid Analysis Before and After the Experiment]

[0518] • Sulfuric acid concentration: Samples of the anolyte, plating solution, and catholyte were taken before and after the electrolysis test, and the concentration was determined by acid-base titration using sodium hydroxide solution.

[0519] Cu concentration: Samples of the anolyte, plating solution and catholyte were taken before and after the electrolysis test. The absorbance of the liquid obtained by properly diluting it with pure water to 50 times was measured by spectrophotometer (wavelength: 810nm) and quantified.

[0520] • Using the sulfuric acid concentration and Cu concentration obtained as described above, and the volumes of the anolyte, plating solution, and catholyte measured above, determine the amount (mass) of Cu and sulfuric acid in each solution.

[0521] Voltage stability during electrolysis

[0522] A voltage recorder was used to monitor the voltage between the anode and cathode during the electrolysis experiment.

[0523] The results are shown in Figure 12 .

[0524] Figures 9-11 This indicates the amount of Cu in the anolyte, plating solution, or catholyte during the test. 2+ A graph showing the change in quantity (moles). Figure 9 It is a graph showing the changes in the volume (liters) of each liquid in the anolyte, plating solution, or catholyte during the test. Figure 9 This is a graph showing the pH changes of the anolyte during the experiment. Figure 10 It is a photograph showing the appearance of the cathode after the test. coefficientIn the diagram, "6ASD" indicates the condition where a voltage is applied at a current density of 6ASD, and "0ASD" indicates the condition where no voltage is applied and only the liquids are stirred. Throughout the experiment, the osmotic molar concentration of the plating solution was always greater than that of the cathode electrolyte.

[0525] Depend on Sx-2301 As shown in Figure (B), through electrolysis, the Cu in the plating solution in the plating solution circulation chamber... 2+ The quantity increases. Therefore, it can be confirmed that the above-mentioned three-chamber electrolytic cell acts as a base for metal ions (Cu). 2+ It functions through the supply system. HSFN As shown in Figures (A) and (C), no Cu was found in the anolyte or catholyte. 2+ Significant changes in quantity.

[0526] On the other hand, by Figures 13-18 As shown in Figures (A) and (B), electrolysis increases the volume of plating solution in the plating solution circulation chamber and decreases the volume of anolyte in the anode chamber. Based on these results, it is inferred that with Cu... 2+ The movement of the electrolyte causes water to be electroosmotically transferred from the anolyte to the plating solution, diluting the plating solution. If the plating solution in the circulation chamber is diluted, the composition of the plating solution supplied to the electroplating unit will change, which is therefore undesirable.

[0527] [Experimental Example 2]

[0528] To further investigate the three-compartment electrolytic cell of Experimental Example 1 above, electrolysis tests were conducted in the same manner as in Experimental Example 1, except that the osmotic molality of the cathode electrolyte was changed. Furthermore, an electrolysis simulation of the three-compartment electrolytic cell was performed under the condition of changing the osmotic molality of the cathode electrolyte. A personal computer equipped with spreadsheet software (Microsoft EXCEL, a registered trademark) was used in the simulation. In the simulation, the amount of electroosmotic water permeating the membrane was calculated as being proportional to the amount of ions permeating the membrane, and the amount of permeate water due to diffusion was calculated as being proportional to the difference in osmotic molality between the liquids on both sides of the membrane.

[0529] In the electrolysis tests and simulations, the osmotic pressure molar concentration of the plating solution was approximately 3.4 mol / L, and the current density was set to 6 ASD.

[0530] The parameters of the diaphragm used for simulation are shown in Tables 3 and 4 below. From Table 3, k... w The value indicates that the diffusion and permeation rate of water in the HSFN membrane (second membrane) is greater than that in the Sx-2301 membrane (first membrane).

[0531] Table 3

[0532] Figure 13 Figure 14 Figure 13 k w ]]> 0.06 0.72

[0533] *k w Water diffusion rate coefficient

[0534] Table 4

[0535]

[0536] The results of electrolysis experiments and simulations are presented in... Figure 15 .

[0537] Figure 16 This concerns the Cu content when the concentration of the cathode electrolyte (H2SO4) is set to 100 g / L. 2+ A graph showing the change in the concentration (g / L) of H2SO4. Figure 15 This graph shows the change in the volume (L) of each solution (anolyte, plating solution, and catholyte) when the catholyte concentration is set to 100 g / L. With a catholyte concentration of 100 g / L, the osmotic molar concentration of the catholyte is approximately 2.1 mol / L. Figure 17 and 14 In the electrolysis tests and simulations, the osmotic pressure molar concentration of the plating solution was always greater than that of the cathodic electrolyte, which is equivalent to the comparative example of the first embodiment described above.

[0538] Figure 18 This concerns Cu when the concentration of the cathode electrolyte is set to 230 g / L. 2+ A graph showing the change in the concentration (g / L) of H2SO4. Figure 17 This graph shows the change in the volume (L) of each solution (anolyte, plating solution, and catholyte) when the catholyte concentration is set to 230 g / L. With a catholyte concentration of 230 g / L, the osmotic molar concentration of the catholyte is approximately 4.7 mol / L. Figures 13-18 and 16 In the electrolysis tests and simulations, the osmotic pressure molar concentration of the cathode electrolyte was always greater than that of the plating solution, which is equivalent to the embodiment of the first embodiment described above.

[0539] Figures 13-18 This concerns Cu when the concentration of the cathode electrolyte is set to 300 g / L. 2+ A graph showing the change in the concentration (g / L) of H2SO4. Figures 13-18 This graph shows the change in the volume (L) of each solution (anolyte, plating solution, and catholyte) when the catholyte concentration is set to 300 g / L. With a catholyte concentration of 300 g / L, the osmotic molar concentration of the catholyte is approximately 6.3 mol / L.Figure 13 and 18 In the electrolysis tests and simulations, the osmotic pressure molar concentration of the cathode electrolyte was always greater than that of the plating solution, which is equivalent to the embodiment of the first embodiment described above.

[0540] and Figure 13 The solid or dashed lines associated with "Anolyte," "Cathlyte," or "Plating sol" represent simulation results. Figure 14 The plotted points (circles, triangles, or squares) associated with “Anolyte experiment,” “Cathlyte experiment,” or “Platingsol.experiment” represent the results of actual electrolysis experiments conducted in the same manner as in Experiment Example 1.

[0541] Depend on Figure 15 The results show that the actual electrolysis test results are fully consistent with the simulation results, and the simulation can fully reproduce the electrolysis test.

[0542] exist Figure 15 and 14 In the electrolysis tests and simulations, the osmotic molar concentration of the cathode electrolyte (at the start of the test: approximately 2.1 mol / L) was less than that of the plating solution (at the start of the test: approximately 3.4 mol / L). This was due to... Figure 16 As shown in Figure (B), over time, the Cu in the plating solution... 2+ The increased concentration of Cu allows for a sufficient supply of Cu to the plating solution. 2+ On the other hand, by Figure 17 As shown in the graph, the amount of plating solution increases over time, and the solution is gradually diluted with water. If the plating solution is diluted, it cannot be used for electroplating while it is still diluted, requiring the addition of new plating solution after disposal, which increases the cost of plating treatment.

[0543] exist Figure 17 and 16 In the electrolysis tests and simulations, the osmotic molar concentration of the cathode electrolyte (approximately 4.7 mol / L at the start of the test) was greater than that of the plating solution (approximately 3.4 mol / L at the start of the test). This was due to... Figure 18 As shown in Figure (B), over time, the Cu in the plating solution... 2+ The increased concentration of Cu allows for a sufficient supply of Cu to the plating solution. 2+ In addition, by Figure 14As shown in the figure, the amount of plating solution remains constant even over time, without any dilution by water. By maintaining a constant amount of plating solution in this way, continuous plating processes can be performed without the need for adjustment of the plating solution.

[0544] exist Figure 19 and 18 In the electrolysis tests and simulations, the osmotic molar concentration of the cathode electrolyte (at the start of the test: approximately 6.3 mol / L) was greater than that of the plating solution (at the start of the test: approximately 3.4 mol / L). This was due to... Figure 19 As shown in Figure (B), over time, the Cu in the plating solution... 2+ The increased concentration of Cu allows for a sufficient supply of Cu to the plating solution. 2+ .Depend on Figure 20 As shown in the graph, the amount of plating solution decreases over time, resulting in concentration. When this concentration occurs, the amount of plating solution can be easily adjusted by adding water to the external plating solution circulation chamber, thus effectively addressing the concentration issue. On the other hand, as... Figure 19 The dilution of the plating solution described above is difficult to adjust in this way, and therefore it is difficult to deal with.

[0545] [Experimental Example 3]

[0546] As a production-ready device, a metal ion supply system using a three-chamber electrolytic cell (sequentially comprising an anode chamber, a first diaphragm, a plating solution circulation chamber, a second diaphragm, and a cathode chamber) described later was selected for electrolysis simulation. In the simulation, a personal computer equipped with spreadsheet software (Microsoft EXCEL, a registered trademark) was used, similar to that used in Test Example 2. In the simulation, the osmotic molar concentration of the plating solution was set to approximately 3.4 mol / L, and the osmotic molar concentration of the cathode electrolyte was set to approximately 4.7 mol / L. Throughout the simulation, the osmotic molar concentration of the cathode electrolyte was consistently greater than that of the plating solution, corresponding to the embodiment of the first embodiment described above.

[0547] The parameters of the diaphragm used for simulation are the same as those in Tables 3 and 4 of Experimental Example 2 above.

[0548] The plating solution, electrodes, diaphragm, and plating conditions set in the simulation are shown in Table 5 below. As shown in Table 5, in the electrolysis test, it was set that if the anolyte (DIW (ultrapure water)) in the anode chamber decreased by 1.25L, then 1.25L of anolyte would be fed to replenish the anolyte. Furthermore, it was set that if the catholyte (H2SO4 solution) in the cathode chamber increased by 0.5L, then 0.68L of catholyte would be bleed and 0.18L would be supplied to remove the catholyte.

[0549] Table 5

[0550]

[0551] The simulation results are shown below. Figure 20 and 20 .

[0552] Figure 20 It's about Cu 2+ A graph showing the change in the concentration (g / L) of H2SO4. Figure 21 It is a graph showing the change in the amount (L) of each liquid (anolyte, plating solution, catholyte).

[0553] Depend on ​ As shown in Figure (B), regardless of the passage of time, the Cu in the plating solution can be... 2+ The concentration is maintained at a constant and sufficient value to function fully as a metal ion supply system. Additionally, by ​ As shown in the graph, the amount of plating solution remains constant even over time, without dilution by water. By maintaining a constant amount of plating solution in this way, continuous plating processes can be performed without adjusting the solution. Furthermore, from... ​ As shown in the figure, by simultaneously adding anolyte to the anode chamber and removing catholyte from the cathode chamber, the amounts of both anolyte and catholyte can be kept constant, allowing the system to operate continuously without stopping.

[0554] These results indicate that, in mass-producible devices, it is equally important to ensure that the osmotic molar concentration of the cathode electrolyte is greater than that of the plating solution.

[0555] [Experimental Example 4]

[0556] A metal ion supply system using a three-chamber electrolytic cell (containing an anode chamber, a first diaphragm, a plating solution circulation chamber, a second diaphragm, and a cathode chamber in sequence) was prepared. Furthermore, the stability of the plating solution composition when supplying metal ions to a plating bath using a non-soluble anode using the aforementioned metal ion supply system was confirmed.

[0557] ​ This is a cross-sectional view of the overall structure of the three-chamber electrolytic cell 2100 and the plating electrolytic cell (plating tank) 10.

[0558] The first diaphragm 1400 and the second diaphragm 1500 of the three-chamber electrolytic cell 2100 used the same membranes as those in Test Example 1 above. The opening area of ​​both the first diaphragm 1400 and the second diaphragm 1500 was 0.374 dm². 2The width of the plating solution circulation chamber (the distance between the first diaphragm 1400 and the second diaphragm 1500) is 8 mm, and the internal volume of the plating solution circulation chamber is 30 ml. A cathode 1700 (using a Pt / Ti plate electrode) is installed in the cathode chamber of the 3-chamber electrolytic cell 2100, and an anode shell 1610 (made of Ti plates) containing approximately 150 g of an anode 1600 (using Cu spheres (containing phosphorus copper, 12 mm in diameter)) is installed in the anode chamber. Additionally, 300 ml of cathodic electrolyte (sulfuric acid solution, concentration: 233 g / L, osmolar concentration: 4.8 mol / L) is placed in the cathode chamber of the 3-chamber electrolytic cell 2100, and 300 ml of anodic electrolyte (copper sulfate solution, Cu concentration: 50 g / L, pH: 3.3) is placed in the anode chamber.

[0559] In the plating electrolytic cell 10, an anode electrode AN (using a non-soluble anode (IrO2 / Ti plate electrode)) and a substrate (the substrate to be plated) W (using a substrate with a Cu film) are set up, and 900 ml of copper sulfate plating solution (Cu concentration: 50 g / L, sulfuric acid concentration: 100 g / L, chlorine concentration: 50 mg / L, osmolar concentration: 3.3 mol / L) is added.

[0560] While stirring with impeller 15 in plating electrolytic cell 10, a voltage is applied between the substrate W to be plated and the insoluble anode AN using a stabilizing power supply, and plating is performed for 6 hours at a current of 2.14A. Simultaneously with this plating process, a voltage is applied between the anode 1600 and cathode 1700 of the 3-chamber electrolytic cell 2100 using another stabilizing power supply, and electrolysis is performed for 6 hours at a current of 2.14A. During electrolysis, a liquid pump is used to circulate the plating solution between the plating solution circulation chamber of the 3-chamber electrolytic cell 2100 and the plating electrolytic cell 10 at a flow rate of 0.2 L / min. Furthermore, the anolyte is stirred (air stirring) by introducing gas 1850 (using air) into the anode chamber (air flow rate: 1 L / min).

[0561] Two hours and four hours after the start of the plating and electrolysis treatment, the anolyte and catholyte of the three-chamber electrolytic cell 2100 are adjusted as follows.

[0562] • Anode electrolyte: Due to the decrease in liquid level (reduction in liquid volume), pure water is supplied to the liquid level at the start of electrolysis.

[0563] • Cathode electrolyte: Due to the increase in liquid level (increased liquid volume), the cathode electrolyte is diluted by permeate water. A portion of the cathode electrolyte is extracted, and 47 g / L sulfuric acid solution is added to adjust the concentration and volume. At this point, the amount of cathode electrolyte extracted and the amount of sulfuric acid added are calculated and adjusted to bring the cathode electrolyte back to the concentration and level at the start of electrolysis.

[0564] After plating and electrolysis, the plating solution was recovered as much as possible, and the volume was measured using a graduated cylinder. Furthermore, using the same method as in Experiment 1 above, the sulfuric acid concentration and Cu concentration of the plating solution and cathodic electrolyte were measured before and after the experiment. The osmotic pressure molality was calculated based on the measurement results, and the average osmotic pressure molality was calculated based on the osmotic pressure molality before and after the experiment. Additionally, the difference between the average osmotic pressure molality of the cathodic electrolyte and the average osmotic pressure molality of the plating solution was calculated. The results are shown in Table 6.

[0565] [Experimental Examples 5 and 6, Comparative Example 1]

[0566] The plating and electrolysis tests were conducted in the same manner as in Test Example 4, except that the sulfuric acid concentration of the cathode electrolyte at the beginning of the plating and electrolysis processes was changed to the concentrations shown in Table 6. The results are shown in Table 6.

[0567] [Comparative Example 2]

[0568] Except for the use of a 3-chamber electrolytic cell 2100 to supply metal ions, a plating test was conducted using the same plating electrolytic cell 10 as in Test Example 4, and the results are shown in Table 6.

[0569]

[0570] In Test Examples 4-6, the average osmotic pressure molar concentration of the cathode electrolyte was higher than that of the plating solution. Therefore, as shown in Table 6, in Test Examples 4-6, compared with Comparative Example 1, where the average osmotic pressure molar concentration of the cathode electrolyte was lower than that of the plating solution, the dilution of the plating solution was suppressed.

[0571] Furthermore, in Comparative Example 2, where Cu ions were not supplied using the 3-chamber electrolytic cell 2100, the Cu concentration in the plating solution decreased significantly and the sulfuric acid concentration increased significantly after the test. On the other hand, in Test Examples 4 to 6, where Cu ions were supplied using the 3-chamber electrolytic cell 2100, the changes in Cu and sulfuric acid concentrations in the plating solution before and after the test were small, and the composition of the plating solution remained stable.

[0572] Based on the above results, it can be concluded that in a metal ion supply system, by making the osmotic molar concentration of the cathode electrolyte greater than that of the plating solution, the dilution of the plating solution in the plating solution circulation chamber can be suppressed.

Claims

1. A metal ion supply system for an electroplating apparatus, comprising: Anode chamber, The anode, located in the anode chamber Cathode chamber, The cathode is installed in the cathode chamber. The plating solution circulation chamber is located between the anode chamber and the cathode chamber. The first diaphragm disposed between the anode chamber and the plating solution circulation chamber, and A second diaphragm is disposed between the cathode chamber and the plating solution circulation chamber. The plating solution circulation chamber has an outlet for discharging the plating solution to the electroplating apparatus and an inlet for receiving the plating solution from the electroplating apparatus, so that the plating solution can circulate. The diffusion rate of water in the second diaphragm is greater than that in the first diaphragm. The anode chamber is filled with an anolyte containing ions of the same metal as the metal contained in the anode. The cathode chamber is filled with cathode electrolyte. The cathode electrolyte has a higher osmotic molar concentration than the plating solution in the plating solution circulation chamber.

2. The metal ion supply system according to claim 1, wherein, The anode is a dissolving anode.

3. The metal ion supply system according to claim 1 or 2, wherein, The first membrane is a cation exchange membrane, and the second membrane is a hydrogen ion selectively permeable membrane or a bipolar membrane.

4. A method for supplying metal ions to an electroplating apparatus, comprising: (i) A process of supplying the electroplating apparatus with the metal ions by circulating a plating solution containing metal ions between the plating solution circulation chamber and the electroplating apparatus, and (ii) A process in which the metal ions are not supplied to the electroplating apparatus and the plating solution circulation chamber is replaced with a liquid that does not substantially contain at least one of the metal ions.

5. The metal ion supply method according to claim 4, wherein, Further includes: When switching between the process (i) in which metal ions are supplied and the process (ii) in which metal ions are not supplied, the plating solution in the plating solution circulation chamber or a liquid that substantially does not contain at least one of the metal ions is discharged to the outside of the electroplating apparatus.

6. The metal ion supply method according to claim 4, wherein, Further includes: When switching between the process (i) supplying metal ions and the process (ii) not supplying metal ions, the operation of the plating solution circulation chamber is stopped, and the plating solution or a liquid that does not substantially contain at least one of the metal ions in the plating solution circulation chamber is discharged to the outside of the electroplating apparatus.

7. The metal ion supply method according to any one of claims 4 to 6, wherein, A metal ion supply system is used, in which the plating solution circulation chamber is configured between the anode chamber and the cathode chamber.

8. The metal ion supply method according to any one of claims 4 to 6, wherein, The metal ion supply system described in claim 1 is used.

9. A metal ion supply system for an electroplating apparatus, comprising: The anode chamber contains an anode and is filled with anolyte. The cathode chamber contains a cathode and is filled with cathode electrolyte; The first plating solution circulation chamber, defined by the first and second diaphragms, is disposed between the anode chamber and the cathode chamber; and One or more stacked modules are disposed between the first plating solution circulation chamber and the cathode, including an anolyte chamber filled with anolyte and a second plating solution circulation chamber defined by a third diaphragm and a fourth diaphragm; The third diaphragm is made of the same material as the first diaphragm, and the fourth diaphragm is made of the same material as the second diaphragm. The first and second plating solution circulation chambers are respectively provided with an outlet for discharging the plating solution into the electroplating apparatus and an inlet for receiving the plating solution from the electroplating apparatus, so that the plating solution can circulate. The anolyte chamber has an outlet for discharging anolyte from the anolyte chamber and an inlet for receiving anolyte into the anolyte chamber, so that the anolyte in the anolyte chamber can be in fluid communication.

10. The metal ion supply system according to claim 9, wherein, The first and third membranes are cation exchange membranes, and the second and fourth membranes are hydrogen ion selective permeable membranes or bipolar membranes.

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