Liquid management method for anode chamber and plating device

Abstract

A method for managing liquid in an anode chamber, comprising the following steps: preparing a plating tank, the plating tank being provided with an anode and a diaphragm in contact with or in close contact with the upper surface of the anode, and having an upper cathode chamber and a lower anode chamber separated by the diaphragm, and an exhaust passage connected to the anode chamber and used to exhaust bubbles from the anode chamber to the outside of the plating tank; maintaining plating liquid in the anode chamber and the cathode chamber, and making the liquid level of the plating liquid in the anode chamber, that is, the liquid level of the plating liquid in the exhaust passage, lower than the liquid level of the plating liquid in the cathode chamber; based on the output of a liquid level sensor arranged in the exhaust passage, determining whether the height of the liquid level of the plating liquid in the exhaust passage is less than a specified height; and supplying pure water or an electrolyte to the anode chamber when it is determined that the height of the liquid level of the plating liquid in the exhaust passage is less than the specified height.

Description

Technical Field

[0001] The present invention relates to a liquid management method for an anode chamber, and in particular to a liquid management method for an anode chamber of a plating device and a plating device. Background Art

[0002] As a plating device capable of performing a plating process on a substrate such as a semiconductor wafer, a plating device such as that described in the specification of U.S. Patent Application Publication No. 2020-0017989 (Patent Document 1) is known. The plating device comprises: a plating tank that stores a plating solution and is provided with an anode; a substrate holder that holds the substrate as a cathode so that the substrate is arranged facing the anode; and a diaphragm that is arranged between the anode and the substrate holder and divides the inside of the plating tank into an anode chamber and a cathode chamber, and the plating device allows the plating solution to flow along the surface of the substrate. The diaphragm is arranged on the lower side of a frame fixed in the plating tank, but if the pressure in the cathode chamber is higher than that in the anode chamber, there is a situation in which the diaphragm leaves the frame and extends downward, and a pocket for capturing bubbles is formed between the frame and the diaphragm. To prevent this phenomenon, in the device of U.S. Patent Application Publication No. 2020-0017989 (Patent Document 1), the supply of plating solution to the anode chamber is adjusted so that the pressure of the anode chamber is higher than the pressure of the cathode chamber to prevent the diaphragm from extending downward.

[0003] Patent Document 1: U.S. Patent Application Publication No. 2020-0017989

[0004] In a structure in which the diaphragm (membrane) is in close contact with the anode, as in the plating module described in [International Patent Application No. PCT / JP2022 / 016809] proposed by the applicant, in order to ensure close contact between the diaphragm and the anode by the pressure difference between the cathode chamber and the anode chamber, the liquid level of the plating solution (anode solution) in the anode chamber needs to be always controlled to be lower than the liquid level of the plating solution (cathode solution) in the cathode chamber. In addition, it is necessary to prevent the anode solution from drying up. Summary of the invention

[0005] The present invention has been made in view of the above circumstances, and one of its purposes is to control the liquid level of the anolyte to be lower than the liquid level of the cathode liquid in a plating device and prevent the reduction or depletion of the anolyte.

[0006] According to one aspect of the present invention, a method for managing liquid in an anode chamber is provided, comprising the following steps: preparing a plating tank, the plating tank being provided with an anode and a diaphragm in contact with or in close contact with the upper surface of the anode, and having an upper cathode chamber and a lower anode chamber separated by the diaphragm, and an exhaust passage connected to the anode chamber and used to exhaust bubbles from the anode chamber to the outside of the plating tank; maintaining plating liquid in the anode chamber and the cathode chamber, and making the liquid level of the plating liquid in the anode chamber, that is, the liquid level of the plating liquid in the exhaust passage, lower than the liquid level of the plating liquid in the cathode chamber; based on the output of a liquid level sensor arranged in the exhaust passage, determining whether the height of the liquid level of the plating liquid in the exhaust passage is less than a specified height; and supplying pure water or an electrolyte to the anode chamber when it is determined that the height of the liquid level of the plating liquid in the exhaust passage is less than the specified height. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a perspective view showing the overall structure of a plating apparatus according to one embodiment.

[0008] Figure 2 It is a plan view showing the overall structure of a plating apparatus according to one embodiment.

[0009] Figure 3 This is a cross-sectional view for explaining the structure of a plating module according to one embodiment.

[0010] Figure 4 This is a cross-sectional view of a part of the plating module which is enlarged.

[0011] Figure 5 This is an enlarged cross-sectional view near the anode.

[0012] Figure 6 It is a cross-sectional view showing an example of a fixing structure of the diaphragm 71 to the anode 41 .

[0013] Figure 7 It is a cross-sectional view showing an example of a fixing structure of the diaphragm 71 to the anode 41 .

[0014] Figure 8 It is a flow chart of anode chamber liquid management control.

[0015] Fig. 9 This is a photo of the plating module (without diaphragm) used in the experiment.

[0016] Fig.10 This is a photo of the plating module (with diaphragm) used in the experiment.

[0017] Fig.11 This is the measurement result of the anode voltage during plating.

[0018] Fig. 12AThis is a photograph of a plating module (without a diaphragm) before plating.

[0019] Fig. 12B This is a photograph of a plating module (without a diaphragm) during plating.

[0020] Fig.13A This is a photo of a plating module (with a diaphragm) before plating.

[0021] Fig. 13B This is a photo of a plating module (with a diaphragm) during plating. DETAILED DESCRIPTION

[0022] Hereinafter, the plating device 1000 according to the embodiment of the present invention will be described with reference to the accompanying drawings. In addition, the accompanying drawings are schematically illustrated for easy understanding of the characteristics of the object, and are not limited to the case where the size ratio of each structural element is the same as the actual one. In addition, several drawings illustrate the orthogonal coordinates of XYZ for reference. In the orthogonal coordinates, the Z direction corresponds to the top, and the -Z direction corresponds to the bottom (the direction in which gravity acts).

[0023] (First embodiment)

[0024] Figure 1 It is a perspective view showing the overall structure of the plating apparatus 1000 according to the present embodiment. Figure 2 1 is a top view showing the overall structure of the plating device 1000 of this embodiment. Figure 1 and Figure 2 As shown, the plating apparatus 1000 includes a loading port 100 , a transfer robot 110 , an aligner 120 , a pre-wet module 200 , a pre-preg module 300 , a plating module 400 , a cleaning module 500 , a spin cleaning dryer 600 , a transfer device 700 , and a control module 800 .

[0025] The loading port 100 is a module for carrying wafers (substrates) stored in a box such as a FOUP (not shown) into the plating device 1000, or for carrying substrates out of the plating device 1000 to a box. In the present embodiment, four loading ports 100 are arranged in a horizontal direction, but the number and configuration of the loading ports 100 are arbitrary. The transport robot 110 is a robot for transporting substrates, and is configured to transfer substrates between the loading port 100, the aligner 120, the pre-wetting module 200, and the spin cleaning dryer 600. When the transport robot 110 and the transport device 700 transfer substrates between the transport robot 110 and the transport device 700, the substrates can be transferred via a temporary placement table (not shown).

[0026] The aligner 120 is a module for aligning the orientation plane, notch, etc. of the substrate in a specified direction. In the present embodiment, two aligners 120 are arranged in a horizontal direction, but the number and configuration of the aligners 120 are arbitrary. The pre-wet module 200 wets the plated surface of the substrate before the plating process with a processing liquid such as pure water or degassed water, thereby replacing the air inside the pattern formed on the surface of the substrate with the processing liquid. The pre-wet module 200 is configured to replace the processing liquid inside the pattern with the plating liquid during plating, thereby implementing a pre-wet treatment that makes it easy to supply the plating liquid to the inside of the pattern. In the present embodiment, two pre-wet modules 200 are arranged in a vertical direction, but the number and configuration of the pre-wet modules 200 are arbitrary.

[0027] The prepreg module 300 is configured to perform a prepreg treatment, and the prepreg treatment, for example, uses a treatment solution such as sulfuric acid and hydrochloric acid to etch away a high-resistance oxide film existing on the surface of the seed layer formed on the plated surface of the substrate before the plating treatment, and cleans or activates the surface of the plated base. In the present embodiment, two prepreg modules 300 are arranged in the vertical direction, but the number and arrangement of the prepreg modules 300 are arbitrary. The plating module 400 performs a plating treatment on the substrate. In the present embodiment, there are two groups of 12 plating modules 400, three of which are arranged in the vertical direction and four of which are arranged in the horizontal direction, and a total of 24 plating modules 400 are provided, but the number and arrangement of the plating modules 400 are arbitrary.

[0028] The cleaning module 500 is configured to perform cleaning on the substrate in order to remove the plating liquid and the like remaining on the substrate after the plating treatment. In the present embodiment, two cleaning modules 500 are arranged in the vertical direction, but the number and configuration of the cleaning modules 500 are arbitrary. The spin cleaning dryer 600 is a module for rotating the substrate after the cleaning treatment at high speed to dry the substrate. In the present embodiment, two spin cleaning dryers 600 are arranged in the vertical direction, but the number and configuration of the spin cleaning dryers 600 are arbitrary. The transport device 700 is a device for transporting substrates between multiple modules in the plating device 1000. The control module 800 is configured to control multiple modules of the plating device 1000, and can be configured by, for example, a conventional computer or a dedicated computer having an input / output interface between itself and an operator.

[0029] An example of a series of plating processes performed by the plating device 1000 is described. First, a substrate stored in a box is carried in at the loading port 100. Next, the transport robot 110 takes out the substrate from the box of the loading port 100 and transports the substrate to the aligner 120. The aligner 120 aligns the orientation plane, notch, etc. of the substrate in a predetermined direction. The transport robot 110 delivers the substrate aligned by the aligner 120 to the pre-wet module 200.

[0030] The pre-wet module 200 performs a pre-wet treatment on the substrate. The transport device 700 transports the substrate subjected to the pre-wet treatment to the pre-preg module 300. The pre-preg module 300 performs a pre-preg treatment on the substrate. The transport device 700 transports the substrate subjected to the pre-preg treatment to the plating module 400. The plating module 400 performs a plating treatment on the substrate.

[0031] The transport device 700 transports the substrate subjected to the plating process to the cleaning module 500. The cleaning module 500 performs a cleaning process on the substrate. The transport device 700 transports the substrate subjected to the cleaning process to the spin cleaning dryer 600. The spin cleaning dryer 600 performs a drying process on the substrate. The transport robot 110 receives the substrate from the spin cleaning dryer 600 and transports the substrate subjected to the drying process to the box of the loading port 100. Finally, the box containing the substrate is unloaded from the loading port 100.

[0032] in addition, Figure 1 , Figure 2 The structure of the plating device 1000 described in the above is merely an example, and the structure of the plating device 1000 is not limited to Figure 1 , Figure 2 structure.

[0033] The control module 800 includes, for example, a CPU and a volatile memory and / or a nonvolatile memory. The memory is also referred to as a storage medium or a recording medium. The memory stores various programs, various parameters, etc. The CPU reads out various programs, various parameters, etc., and executes various programs.

[0034] [Plating Module]

[0035] Next, the plating module 400 will be described. In addition, since the plurality of plating modules 400 included in the plating apparatus 1000 according to the present embodiment have the same structure, one plating module 400 will be described.

[0036] Figure 3 This is a cross-sectional view for explaining the structure of a plating module according to one embodiment. Figure 4 This is a cross-sectional view of a part of the plating module which is enlarged.

[0037] The plating device 1000 according to the present embodiment is a so-called face-down type or cup type plating device in which the plated surface of the substrate is placed downward to contact the plating solution. The plating module 400 of the plating device 1000 according to the present embodiment mainly includes a plating tank 10, an anode 41 arranged in the plating tank 10, and a substrate holder 31 that holds the substrate Wf as a cathode in a manner arranged to face the anode 41. The plating module 400 can include a rotating mechanism, a tilting mechanism, and / or a lifting mechanism (not shown) that rotates, tilts, and / or lifts the substrate holder 31. In addition, the plating tank 10 can include: an inner tank 10a including a cathode chamber Cc and an anode chamber Ca, and an outer tank 10b that serves as an overflow tank (overflow chamber) 20.

[0038] The plating tank 10 is composed of a bottomed container with an opening at the top. The plating tank 10 (inner tank 10a) has a bottom wall and a side wall extending upward from the outer periphery of the bottom wall, and the upper part of the side wall is open. The plating tank 10 (inner tank 10a) has a cylindrical internal space for storing the plating solution Ps. As a plating solution, any solution containing ions of metal elements constituting the plating film can be used, and its specific example is not particularly limited. In this embodiment, as an example of a plating treatment, a copper plating treatment is used, and as an example of a plating solution, a copper sulfate solution is used. In addition, in this embodiment, the plating solution contains a prescribed additive. However, it is not limited to this structure, and the plating solution can also be a structure that does not contain additives. The plating tank 10 (inner tank 10a) is divided into an upper cathode chamber Cc and a lower anode chamber Ca by a diaphragm 71. In the present embodiment, the plating solution (anolyte) Ps of the anode chamber Ca and the plating solution (cathode solution) Ps of the cathode chamber Cc are supplied from the same supply source and have the same composition. Among them, the difference caused by the time change of the plating solution Ps of the anode chamber Ca and the cathode chamber Cc due to the evaporation of water in the plating solution, etc. can be generated. In addition, an exhaust passage 11 connected to the anode chamber Ca and open to the atmosphere is provided in the plating tank 10. The exhaust passage 11 discharges the bubbles 61 in the anode liquid in the anode chamber Ca. In the present embodiment, at least a part of the exhaust passage 11 extends in the up and down direction outside the overflow tank 20 (outer tank 10b) and opens to the atmosphere at the exhaust passage outlet.

[0039] The overflow tank 20 is a bottomed container disposed outside the inner tank 10a of the plating tank 10. The overflow tank 20 temporarily stores the plating solution that exceeds the overflow surface OFc (in this example, the upper end of the inner tank 10a of the plating tank 10). In one example, the plating solution of the overflow tank 20 is discharged from the discharge port for the overflow tank 20, transported to the storage tank 81 through the flow path 95, and returned to the cathode chamber Cc of the plating tank 10 again after being temporarily stored in the storage tank 81.

[0040] The anode 41 is disposed at the lower part of the inside of the plating tank 10. The specific type of the anode 41 is not particularly limited, and a soluble anode or an insoluble anode can be used. In the present embodiment, an insoluble anode is used as the anode 41. The specific type of the insoluble anode is not particularly limited, and platinum, titanium, iridium oxide, etc. (for example, IrO2 / Ti, Pt / Ti) can be used. In order to suppress the decomposition of additives in the plating solution, etc., a top coating may also be provided on the surface of the anode 41.

[0041] In the present embodiment, an anode shield 43 is provided on the upper surface side (substrate Wf side) of the anode 41. The anode shield 43 is an electric field adjusting member having an opening portion for exposing the anode 41, and adjusting the exposure range of the anode 41 by the opening portion, thereby adjusting the electric field from the anode 41 toward the substrate Wf. The anode shield 43 may also be an anode shield having a predetermined opening size, or may be a variable anode shield capable of changing the opening size. Alternatively, the anode shield 43 may have, for example, a plurality of blades, and the opening size of the opening portion may be adjusted by the same mechanism as the aperture of a camera. There is also a case where the anode shield 43 is omitted.

[0042] A porous resistor 51 is arranged inside the plating tank 10 and above the diaphragm 71. Specifically, the resistor 51 is composed of a porous plate member having a plurality of holes (pores). The plating solution below the resistor 51 can pass through the resistor 51 and flow to the upper side of the resistor 51. The resistor 51 is a member provided to achieve uniformity of the electric field formed between the anode 41 and the substrate Wf. By arranging such a resistor 51 in the plating tank 10, it is possible to easily achieve uniformity of the film thickness of the plating film (plating layer) formed on the substrate Wf. In addition, the resistor 51 is not a necessary structure in the present embodiment, and the present embodiment can also be a structure without the resistor 51.

[0043] Alternatively, a paddle (not shown) may be arranged inside the plating tank 10 and near the substrate Wf (in the present embodiment, between the resistor 51 and the substrate Wf). The paddle reciprocates in a direction substantially parallel to the plated surface of the substrate Wf to generate a strong plating solution flow on the surface of the substrate Wf. Thus, the ions in the plating solution near the surface of the substrate Wf can be homogenized, and the in-plane uniformity of the plated film formed on the surface of the substrate Wf can be improved.

[0044] [Structure of anode and diaphragm]

[0045] In this embodiment, if Figure 5 to Figure 7As shown, the anode 41 is a plate-like member having many through holes 41A. The anode 41 can be an iron mesh (metal mesh) structure, or a plate-like member provided with a plurality of through holes. The thickness of the anode 41 is not particularly limited, but from the perspective of the strength of the anode 41 itself and the oxygen generated on the surface of the anode 41 being easily discharged from the through hole to the back of the anode 41, it is preferably about 0.5 mm to 3 mm. The shape and size of the through hole are not particularly limited, but from the perspective of ease of processing and stability of voltage during plating, the size of the opening (the diameter in the case of a circle and the length of one side in the case of a quadrilateral) is preferably about 1 mm to 5 mm. The anode 41 is supported in the plating tank 10 by an anode holder 42, also referred to as an anode pressing plate.

[0046] like Figure 3 and Figure 4 As shown, a diaphragm 71 (Nafion (registered trademark), porous membrane, etc.) having ion permeability that can be penetrated and wetted by the plating solution is bonded or closely attached to the front surface of the anode 41 (the surface on the cathode / substrate side, the upper surface in this example). In the present embodiment, the interior of the inner tank 10a of the plating tank 10 is separated into the anode chamber Ca and the cathode chamber Cc by the diaphragm 71. The diaphragm 71 is a membrane that allows cations (e.g., hydrogen ions H+) in the plating solution to pass through, but does not allow bubbles (e.g., oxygen) and additives in the plating solution to pass through. When an insoluble anode is used, hydrogen ions H+ are generated in the plating solution on the surface of the anode. The diaphragm 71 can be, for example, a neutral membrane, an ion exchange membrane, or a combination thereof. The diaphragm 71 can also be a structure in which a plurality of membranes or layers are stacked. The structure of the diaphragm 71 is an example, and other structures can be used.

[0047] Figure 5 : is an enlarged cross-sectional view of the vicinity of the anode 41. The anode 41 has many through holes 41A, so the surface of the anode 41 is always kept wet by the plating solution supplied from the through holes 41A during the electrode reaction. The diaphragm 71 is an ion-permeable membrane that can be penetrated and wetted by the plating solution. Therefore, as shown in the figure, the anode 41 reacts with the plating solution on the surface close to the substrate side (the part close to the diaphragm 71 or its vicinity), and cations (such as hydrogen ions H+) pass through the diaphragm 71 and are transferred to the cathode chamber Cc, in other words, the substrate side. Therefore, an ion conduction path (current path) is formed from the surface of the anode 41 close to the substrate side (the part close to the diaphragm 71 or its vicinity) through the inside of the diaphragm 71 to reach the substrate Wf. On the other hand, as shown in the figure, the bubbles 61 of the gas (for example, oxygen O2) generated on the surface of the anode 41 cannot pass through the diaphragm 71, but pass through the many through holes 41A of the anode 41 to move to the back side (the side opposite to the front surface) of the anode 41. The bubbles 61 that have moved to the back side of the anode 41 pass through the exhaust passage 11 ( Figure 3 , Figure 4 ) and discharged to the outside of the plating tank 10.

[0048] In this structure, the diaphragm 71 is in close contact with the surface of the anode 41 on the substrate side, so that the bubbles 61 generated on the surface of the anode 41 can be suppressed from diffusing to the substrate Wf side. Thus, it is possible to suppress the bubbles 61 from diffusing to the substrate side and adhering to the resistor 51, the substrate Wf, etc. In addition, the diaphragm 71 is in close contact with the anode 41, so it is possible to prevent the bubbles 61 from accumulating between the diaphragm 71 and the anode 41. In particular, it is possible to avoid the problem of the bubbles 61 accumulating on the back side of the diaphragm 71 as in the case where the diaphragm 71 is separated from the anode 41. In addition, the back side of the anode 41, which becomes the discharge path of the bubbles 61, is not the main ion conduction path between the anode 41 and the substrate Wf. Therefore, even if there are bubbles 61 here, the bubbles 61 do not become the ion conduction resistance component between the anode and the substrate, and have almost no effect on the ion conduction (plating current) between the anode and the substrate. In this structure, cations (H+) can be conducted from the surface of the anode 41 close to the substrate side (the part to which the diaphragm 71 is in close contact or its vicinity) through the diaphragm 71 to the substrate Wf side, thereby avoiding the influence of the bubbles 61 and effectively ensuring the ion conduction path between the anode 41 and the substrate Wf.

[0049] According to the above, according to this structure, the ion conduction path between the anode and the cathode can be stably ensured, and the bubble 61 can be prevented from accumulating on the ion conduction path between the anode and the cathode and having a negative impact on the ion conduction. As a result, the influence of the bubbles generated by the anode can be suppressed and the plating on the substrate can be stably performed, and the uniformity of the plating film thickness can be improved.

[0050] Figure 6 and Figure 7 4 is a cross-sectional view showing an example of a fixing structure of the diaphragm 71 to the anode 41. In these figures, a power supply protrusion 44 for supplying power to the anode 41 is provided at the center of the back side of the anode 41. The power supply protrusion 44 may be formed integrally with the anode 41 or may be attached to the anode 41. Figure 3 and Figure 4 With the use of the pressure plate 72 ( Figure 6 ) example.

[0051] Figure 6In the example of , the diaphragm 71 is pressed against the surface of the substrate side of the anode 41 by a pressing plate 72 having many through holes 72A, and is fixed in a state of being in close contact with the upper surface of the anode 41. The pressing plate 72 is fixed relative to the anode holder 42 by a fastening member 74 such as a screw in a manner of pressing the anode 41 and the diaphragm 71 from above. In this structure, the diaphragm 71 is clamped by the pressing plate 72 and the anode 41 so that the diaphragm 71 is in close contact with the anode 41. In addition, a sealing member 75 (such as an O-ring) is provided between the pressing plate 72 and the diaphragm 71 to seal therebetween. The anode holder 42 and the pressing plate 72 are preferably made of a material that is not corroded by the plating solution, for example, they can be made of a resin such as vinyl chloride, or a metal such as Pt or Ti.

[0052] Figure 7 In the example, the diaphragm 71 is fixed by bonding to the surface of the anode 41 on the substrate side. It is preferred that the bonding layer 75A that bonds the diaphragm 71 to the anode 41 has ion permeability. For example, it can be a resin having an ion exchange group, a porous bonding layer containing a resin and a filler, and in one example, it can be a perfluorocarbon material having a sulfonic acid group. In addition, the outer peripheral portion of the diaphragm 71 is pressed relative to the anode holder 42 by the pressure ring 73 and fixed. In addition, a sealing member 75 (for example, an O-ring) is provided between the pressure ring 73 and the diaphragm 71 to seal therebetween. The anode holder 42 and the pressure ring 73 are preferably made of a material that is not corroded by the plating solution, for example, they can be made of resins such as vinyl chloride, metals such as Pt and Ti.

[0053] like Figure 3 and Figure 4 As shown in FIG. 1 , a bubble adjustment plate (back plate) 140 is provided below the anode 41 in the anode chamber Ca so as to face the lower surface of the anode 41. A gap is provided between the bubble adjustment plate 140 and the anode 41 by a spacer or the like. The space between the bubble adjustment plate 140 and the anode 41 and the space in the anode chamber outside thereof can be configured to be connected at one or more locations. The bubble adjustment plate 140 removes the bubbles (see FIG. 1 ) accumulated on the lower surface of the anode 41. Figure 5 ) is limited to within the distance between the anode 41 and the bubble adjustment plate 140, so that the amount of bubbles accumulated on the lower surface of the anode 41 is reduced, and the change in the amount of bubbles accumulated accompanied by the detachment of bubbles on the lower surface of the anode 41 during plating is suppressed. As a result, the pressure change of the plating solution near the lower surface of the anode 41 can be suppressed, and the change in the electrode potential in the anode 41 can be suppressed. The change in the electrode potential of the anode during plating can be suppressed, and the degradation of the uniformity of the plated film thickness can be suppressed.

[0054] In addition, a bubble buffer ring (not shown) that surrounds the anode 41 from all sides and protrudes downward from the lower surface of the anode at a predetermined height may be provided instead of the bubble adjustment plate 140. In this case, bubbles are always accumulated on the lower surface of the anode to the height of the end face of the bubble buffer ring, and bubbles are always present on the entire lower surface of the anode, thereby suppressing the change in the amount of bubble accumulation associated with the discharge of bubbles on the lower surface of the anode during plating. In addition, a structure without the bubble adjustment plate 140 and the bubble buffer ring may be provided.

[0055] [Structure of anode chamber liquid level management]

[0056] like Figure 3 and Figure 4 As shown, the plating solution (anolyte) in the anode chamber Ca enters the exhaust passage 11 connected to the anode chamber Ca, and the liquid level Sa of the plating solution in the exhaust passage 11 becomes the liquid level of the plating solution in the anode chamber Ca. The bubbles 61 that move to the back side of the anode 41 are discharged from the exhaust passage 11 to the outside of the plating tank 10. In this structure, the bubbles 61 generated by the anode 41 can be naturally discharged through the exhaust passage 11, and there is no need to circulate the plating solution in the anode chamber Ca to discharge the bubbles.

[0057] The exhaust passage 11 is provided with an overflow passage 11A communicating with the overflow tank 20, and the lower surface of the overflow passage 11A constitutes an overflow surface OFa of the anode chamber Ca. The overflow passage 11A (overflow surface OFa) is provided so that the height thereof is lower than the overflow surface OFc of the cathode chamber Cc.

[0058] The plating liquid surface Sa of the exhaust passage 11 (anode chamber Ca) is set to be lower than the overflow passage 11A (overflow surface OFa), in other words, the plating liquid in the exhaust passage 11 (anode chamber Ca) does not overflow to the overflow tank 20. In other words, even if the volume of bubbles generated in the anode chamber Ca increases and the liquid surface Sa rises, it is set not to overflow to the cathode chamber Cc side, that is, the overflow tank 20. Thus, it is possible to prevent the plating liquid in the anode chamber Ca, which has consumed the additive, from mixing into the cathode chamber Cc via the overflow tank 20 and deteriorating the plating liquid in the cathode chamber Cc.

[0059] In addition, in an emergency situation where the plating solution in the cathode chamber Cc leaks into the anode chamber Ca due to damage of the diaphragm 71 or the like, and the plating solution level in the exhaust passage 11 rises, the plating solution in the exhaust passage 11 overflows to the overflow tank 20 via the overflow passage 11A. In this case, since the overflow surface OFa of the plating solution in the anode chamber Ca is set lower than the overflow surface OFc of the plating solution in the cathode chamber Cc, the pressure in the cathode chamber Cc can be maintained higher than the pressure in the anode chamber Ca, and the diaphragm 71 can be pressed against the anode 41 by the pressure difference, so that the diaphragm 71 can be closely attached to the anode 41.

[0060] A liquid level sensor 12 is arranged in the plating liquid in the exhaust passage 11. The liquid level sensor 12 detects whether the liquid level Sa of the plating liquid in the exhaust passage 11 is above a specified height (whether it is less than a specified height). The liquid level sensor 12 can adopt an electrode type, a floating type (floating switch, etc.), an electrostatic capacitance type, an ultrasonic type, a vibration type, or any other liquid level sensor. The liquid level sensor 12 can, for example, output an on signal when the liquid level Sa of the plating liquid is above a specified height, and output an off signal when the liquid level Sa of the plating liquid is less than a specified height. The liquid level sensor 12 can, for example, measure the distance to the liquid surface. The liquid level sensor 12 is connected to the control module 800 by wire or wirelessly, and the control module 800 receives the output of the liquid level sensor 12.

[0061] In addition, a concentration sensor (conductivity sensor) 13 is arranged in the plating liquid in the exhaust passage 11. There is also a case where conductivity and conductivity sensor are referred to as conductivity and conductivity sensor. The concentration sensor (conductivity sensor) 13 can also be arranged in the anode chamber Ca. The concentration sensor (conductivity sensor) 13 is connected to the control module 800 by wire or wirelessly. The case where the concentration sensor (conductivity sensor) 13 is provided with either a concentration sensor or a conductivity sensor is shown. Among them, both a concentration sensor and a conductivity sensor can also be provided. Both the concentration sensor and the conductivity sensor 13 can also be omitted.

[0062] like Figure 3 As shown, the cathode chamber Cc and the anode chamber Ca receive the supply of plating solution from the storage tank 81. The cathode chamber Cc is connected to the storage tank 81 via flow paths 83 and 82. The anode chamber Ca is connected to the storage tank 81 via flow paths 85, 84, and 82. A pump 86 and a filter 87 are arranged on the flow path 82. A valve 88 is arranged on the flow path 83, and a valve 89 is arranged on the flow path 84. If the valve 88 is opened, the plating solution is supplied from the storage tank 81 to the cathode chamber Cc. If the valve 89 is opened, the plating solution is supplied from the storage tank 81 to the anode chamber Ca. The plating solution overflowing over the overflow surface OFc of the cathode chamber Cc is recovered to the overflow tank 20 and returned to the storage tank 81 via the flow path 95. The storage tank 81, the flow paths 82, 83, the overflow tank 20, and the flow path 95 constitute the circulation path 80 of the cathode chamber Cc. During plating, the plating solution in the cathode chamber Cc circulates through the circulation path 80 .

[0063] In the anode chamber Ca, after the plating liquid is filled from the storage tank 81 to fill the exhaust passage 11 to a predetermined height, the valve 89 is closed and the plating liquid in the anode chamber Ca is not circulated. Figure 3In the plating module 400 shown, the same plating solution as that supplied to the cathode chamber is supplied to the anode chamber, and the plating solution overflowing from the cathode chamber and the anode chamber enters the common overflow tank 20, returns to the common storage tank 81, and is then supplied to the cathode chamber and the anode chamber again. Therefore, if the plating solution is circulated on the anode side during plating, the expensive additives in the anode chamber Ca continue to be decomposed (consumed). Therefore, the plating solution is supplied to the anode chamber Ca only when the anode chamber Ca is filled, and the plating solution in the anode chamber Ca is not circulated.

[0064] In addition, a liquid supply source 91 is connected to the anode chamber Ca via flow paths 85 and 92, and a valve 93 is arranged on the flow path 92. In this example, the liquid supply source 91 is a supply source for supplying pure water (for example, DIW). If the valve 93 is opened, pure water is supplied from the liquid supply source 91 to the anode chamber Ca. The flow paths 85, 92 and the liquid supply source 91 constitute a liquid replenishment path 90. In this embodiment, if the liquid level sensor 12 detects that the liquid level Sa of the plating solution in the anode chamber Ca is less than the specified height H0, the valve 93 is opened and pure water is supplied from the liquid supply source 91 to the anode chamber Ca via the flow paths 92 and 85. In addition, if the concentration sensor (conductivity sensor) 13 detects that the concentration (conductivity) of the plating solution in the anode chamber Ca exceeds the specified concentration (conductivity), the control module 800 issues an alarm. Here, if the water content of the plating solution in the anode chamber Ca evaporates and the plating solution level Sa drops, the concentration (conductivity) of the plating solution increases in accordance with the evaporated water content, and therefore, a concentration exceeding a predetermined concentration (conductivity) corresponds to a level Sa of the plating solution being less than a certain height. In one example, the predetermined concentration (conductivity) can be set to a value corresponding to a predetermined height H0 of the level Sa of the plating solution.

[0065] [Flowchart of anode chamber liquid management control]

[0066] Figure 8 Flow chart showing anode chamber liquid management control. This process is executed by control module 800.

[0067] In step S11, the plating process of the substrate Wf is performed. In step S12, it is determined whether the plating process is completed. If the plating process is not completed, the process returns to step S11 to continue the plating process. If it is determined that the plating process is completed in step S11, the process moves to step S13.

[0068] In step S13, the output of the liquid level sensor 12 is checked. In step S14, it is determined whether the height of the liquid level Sa of the plating solution in the anode chamber Ca is equal to or higher than the lower limit value (predetermined height) H0 based on the output of the liquid level sensor.

[0069] In step S14, when the output of the liquid level sensor 12 indicates that the height of the liquid level Sa of the plating solution in the anode chamber Ca is less than the lower limit value H0 (for example, the sensor output is OFF), the process moves to step S15.

[0070] In step S15, the valve 93 is opened to supply pure water to the anode chamber Ca from the liquid supply source 91. The supply of pure water is performed based on the output of the liquid level sensor 12 until, for example, the height of the liquid level Sa of the plating solution in the anode chamber Ca becomes greater than the lower limit value H0 (the liquid level sensor output is turned on). In the case where the difference between the height of the liquid level Sa of the plating solution supplied to the anode chamber Ca in the initial state and the height of the liquid level Sa of the plating solution at the time when the liquid level sensor 12 is turned off is known, pure water may be supplied in a manner of supplying the plating solution in an amount corresponding to the difference.

[0071] In step S14, when the output of the liquid level sensor 12 indicates that the height of the liquid level Sa of the plating solution in the anode chamber Ca is greater than or equal to the lower limit value H0 (for example, the liquid level sensor output is on), the process proceeds to step S16.

[0072] In step S16, the output of the concentration sensor (conductivity sensor) 13 is checked. In step S17, based on the output of the concentration sensor (conductivity sensor) 13, it is determined whether the concentration (conductivity) of the plating solution in the anode chamber Ca is below the upper limit of the concentration (conductivity).

[0073] In step S17, when the output of the concentration sensor (conductivity sensor) 13 shows that the concentration (conductivity) of the plating solution in the anode chamber exceeds the upper limit of the concentration (upper limit of the conductivity), the process proceeds to step S18 and an alarm is issued. In step S17, when the concentration (conductivity) is out of the normal range, the liquid level sensor 12 fails. In step S14, it is determined that the height of the liquid level Sa is above the lower limit H0, but in fact, the height of the liquid level Sa may be less than the lower limit H0, so an alarm is issued in step S18. The user can confirm whether the liquid level sensor 12 is faulty based on the issuance of the alarm. In the case where both the concentration sensor and the conductivity sensor are present, an alarm may be issued when one of the concentration sensor or the conductivity sensor exceeds the upper limit, or an alarm may be issued when both the concentration sensor and the conductivity sensor exceed the upper limit. In the case where one of the concentration sensor or the conductivity sensor is provided, an alarm is issued when the output of the provided sensor exceeds the upper limit.

[0074] In step S17, when the output of the concentration sensor (conductivity sensor) 13 shows that the concentration (conductivity) of the plating solution in the anode chamber is below the concentration upper limit value (conductivity upper limit value), in step S19, the process of anode chamber liquid management control is terminated and the process is transferred to the next plating process of the substrate (step S11). In the case where both the concentration sensor and the conductivity sensor are present, it can also be set as normal when both the concentration sensor and the conductivity sensor are below the upper limit value, or it can be set as normal when one of the concentration sensor or the conductivity sensor is below the upper limit value. In the case where one of the concentration sensor or the conductivity sensor is provided, it is judged as normal when the output of the provided sensor is below the upper limit value. Here, normal corresponds to the plating liquid level being above the lower limit value H0.

[0075] [Experimental example of plating module]

[0076] An experimental example of observing bubbles generated in a plating solution using the structure of the above-described embodiment will be described below. Fig. 9 This is a photo of the plating module (without diaphragm) used in the experiment. Fig.10 This is a photo of the experimental plating module (with a diaphragm). Fig. 9 In the plating tank 10 holding the plating solution, an anode 41 and a cathode 32 (corresponding to the substrate Wf) separated upward from the anode 41 at a predetermined interval are arranged (see also Fig. 12A , Fig. 12B ). Fig.10 In the plating tank 10 holding the plating solution, an anode 41, a diaphragm 71 in close contact with the upper surface of the anode 41, a pressing plate 72 pressing the diaphragm 71, and a cathode 32 separated upward from the pressing plate 72 at a predetermined interval are arranged. Fig.13A , Fig. 13B ). In each figure, the anode 41 is connected to the positive terminal of a power source (not shown), and the cathode 32 is connected to the negative terminal of the power source. The cathode 32 is separated from the pressing plate 72 due to the buoyancy of the plating solution, but the cathode 32 may be appropriately arranged above a spacer or the like and away from the pressing plate 72.

[0077] Various parameters used in the experiment are as follows. In addition, in order to make it easier to observe the bubble generation in the anode during the experiment, an electrolyte containing no metal ions was used instead of the plating solution. The electrode reaction in the anode is the same as that in the case of using the plating solution. The anode, cathode, electrolyte (plating solution), anode area that functions as an anode facing the cathode, and current density are as follows.

[0078] Anode: IrO2 / Ti iron mesh (metal mesh)

[0079] Cathode: Pt / Ti iron mesh (metal mesh)

[0080] Membrane: Yumicron Y-9207TA (micro-porous membrane) (YUASA Membrane Systems CO., Ltd.)

[0081] Electrolyte: 100g / L-H2SO4

[0082] Anode area: 0.24dm2 (60mm×40mm)

[0083] Current density: 5ASD

[0084] Fig.11 This is the measurement result of the anode voltage during plating. As shown in this measurement result, it can be seen that when the diaphragm 71 is used, the voltage of the anode 41 during power-on is also stable, showing the same voltage change as when there is no diaphragm. According to this result, even if the diaphragm 71 is placed in close contact with the anode 41, the voltage between the anode and the cathode also shows a normal change, and it is expected that a normal plating process can be performed.

[0085] Fig. 12A This is a photograph of a plating module (without a diaphragm) before plating. Fig. 12B 1 and 2 are photos of a plating module (without a diaphragm) during plating. As shown in these figures, it was observed that in the plating module (without a diaphragm), a large number of bubbles generated by the anode 41 accumulated on both sides above and below the anode 41. A large number of bubbles accumulated between the anode 41 and the cathode 32, which form an ion conduction path, and therefore, it is expected to have a negative impact on the uniformity of the plating film thickness.

[0086] Fig.13A This is a photo of a plating module (with a diaphragm) before plating. Fig. 13B These are photos of a plating module (with a diaphragm) during plating. As shown in these figures, it was observed that in the plating module with a diaphragm, bubbles generated by the anode 41 were present on the lower side of the anode 41, but bubbles were suppressed from accumulating between the anode 41 and the cathode 32, which became the ion conduction path. Therefore, it is expected that the uniformity of the plating film thickness can be improved.

[0087] According to the above-described embodiment, one or more of the following effects are achieved.

[0088] (1) According to the above embodiment, the liquid level in the anode chamber is always lower than the liquid level in the cathode chamber. Therefore, the pressure in the cathode chamber higher than the pressure in the anode chamber can press the diaphragm against the anode and bring the diaphragm into close contact with the anode.

[0089] (2) According to the above embodiment, the liquid level in the anode chamber is monitored by a liquid level sensor. When the liquid level in the anode chamber is less than a specified height (lower limit), pure water is supplied to the anode chamber. This can suppress or prevent the plating solution in the anode chamber from drying up.

[0090] (3) According to the above embodiment, the gas generated by the anode is naturally discharged without circulating the plating solution in the anode chamber, so the structure and / or operation of the plating tank are simplified.

[0091] (4) According to the above embodiment, it is possible to suppress the accumulation of bubbles (resistance component) on the ion conduction path between the anode and the substrate, which affects the uniformity of the plating film thickness. In addition, cations can be conducted to the substrate side through the diaphragm close to the anode, thereby avoiding the influence of bubbles and reliably ensuring the ion conduction path between the anode and the substrate. Therefore, it is possible to suppress the ion conduction resistance caused by bubbles from the anode on the ion conduction path between the anode and the substrate, and the plating on the substrate can be stably performed, which can improve the uniformity of the plating film thickness.

[0092] (5) According to the above embodiment, an insoluble anode can be used as the anode, so the maintainability of the anode can be improved and the running cost can be reduced.

[0093] (6) According to the above embodiment, the bubble adjustment plate or the bubble buffer ring can suppress the rapid pressure change near the anode surface (inner wall of the through hole, back surface) caused by the detachment of bubbles accumulated on the back surface of the anode. As a result, the change of the saturated dissolved oxygen concentration near the anode surface (inner wall of the through hole, back surface) can be suppressed, thereby suppressing the change of the electrode voltage of the anode and suppressing the reduction of the in-plane uniformity of the plating film thickness.

[0094] [Modifications]

[0095] (1) In the above embodiment, pure water is supplied to the anode chamber based on the output of the liquid level sensor after the plating process, but pure water may be supplied based on the output of the liquid level sensor in at least one period before the plating process, during the plating process, and after the plating process.

[0096] (2) In the above-mentioned embodiment, an example in which a concentration sensor and / or a conductivity sensor is used in addition to the liquid level sensor is described. However, the concentration sensor and the conductivity sensor may be omitted.

[0097] (3) In the above-mentioned embodiment, pure water is supplied to the anode chamber based on the output of the liquid level sensor, but electrolyte may also be supplied. The electrolyte may also be an electrolyte having a lower concentration than the plating solution in the anode chamber and / or cathode chamber. In order to suppress the change in the concentration of the plating solution in the anode chamber, it is preferred that the electrolyte be an electrolyte having a lower concentration than the plating solution in the anode chamber and / or cathode chamber. In addition, in the case of supplying the electrolyte, the concentration / conductivity of the plating solution in the anode chamber increases each time the electrolyte is supplied, and therefore, the upper limit value for evaluating the detection value of the concentration sensor / conductivity sensor is set in consideration of the concentration of the electrolyte. In addition, the concentration sensor / conductivity sensor and the control based on these sensors may also be omitted ( Figure 8 S16-S18).

[0098] (4) In the above embodiment, the plating solution (anolyte) in the anode chamber is not circulated, but a circulation path for the anode solution different from the circulation path for the cathode solution may be provided. In this case, bubbles in the plating solution in the anode chamber can be more actively discharged to the outside.

[0099] (5) In the above embodiment, the anolyte and the cathode liquid use electrolytes of the same composition, but the anolyte and the cathode liquid may use electrolytes of different compositions. For example, the presence or absence of additives and the concentration of additives may be different in the anolyte and the cathode liquid. For example, the basic composition liquid of the plating liquid (VMS: Virgin Makeup Solution) without additives may be used as the anolyte. In this case, different plating liquid supply paths are set in the cathode chamber and the anode chamber.

[0100] (6) In the above embodiment, a common overflow tank is provided for the cathode liquid and the anode liquid, but overflow tanks for the cathode liquid and the anode liquid may be provided separately. In this case, it is possible to prevent the plating solution containing expensive additives from being supplied to the anode chamber and consuming the additives.

[0101] According to the above-mentioned embodiment, at least the following aspects can be grasped.

[0102] [1] According to one form, a method for managing liquid in an anode chamber is provided, comprising the following steps: preparing a plating tank, the plating tank being provided with an anode and a diaphragm in contact with or in close contact with the upper surface of the anode, and having an upper cathode chamber and a lower anode chamber separated by the diaphragm, and an exhaust passage connected to the anode chamber and used to exhaust bubbles from the anode chamber to the outside of the plating tank; maintaining plating liquid in the anode chamber and the cathode chamber, and making the liquid level of the plating liquid in the anode chamber, that is, the liquid level of the plating liquid in the exhaust passage, lower than the liquid level of the plating liquid in the cathode chamber; based on the output of a liquid level sensor arranged in the exhaust passage, determining whether the height of the liquid level of the plating liquid in the exhaust passage is less than a specified height; and supplying pure water or an electrolyte to the anode chamber when it is determined that the height of the liquid level of the plating liquid in the exhaust passage is less than the specified height. Alternatively, the electrolyte may be an electrolyte having the same composition as the plating solution in the anode chamber and / or cathode chamber, and having a lower concentration than the plating solution in the anode chamber and / or cathode chamber. In order to suppress the change in the concentration of the plating solution in the anode chamber, it is preferred that the electrolyte be an electrolyte having a lower concentration than the plating solution in the anode chamber and / or cathode chamber.

[0103] According to this form, by controlling the liquid level in the anode chamber to be lower than the liquid level in the cathode chamber, the diaphragm can be pressed against the anode by the pressure in the cathode chamber which is higher than the pressure in the anode chamber, and pure water or electrolyte can be supplied to the anode chamber in such a way as to avoid the height of the liquid level in the anode chamber (exhaust passage) being less than a specified height, thereby suppressing or preventing the depletion of the plating solution in the anode chamber.

[0104] [2] According to one embodiment, the plating solution is held in the anode chamber so that the liquid level of the plating solution in the anode chamber becomes a height lower than an overflow height of the plating solution in the anode chamber.

[0105] According to this aspect, the plating solution in the anode chamber that has consumed the additive can be suppressed or prevented from flowing into the overflow tank and circulating to the cathode chamber. Thus, the concentration of the additive in the plating solution in the cathode chamber can be suppressed or prevented from decreasing and deteriorating.

[0106] [3] According to one embodiment, pure water or electrolyte is supplied to the anode chamber so that the liquid level of the plating solution in the anode chamber becomes a height lower than an overflow height of the plating solution in the anode chamber.

[0107] According to this aspect, it is possible to suppress or prevent the plating solution in the anode chamber that has consumed the additive from flowing into the overflow tank and circulating to the cathode chamber, thereby suppressing or preventing the plating solution in the cathode chamber from deteriorating.

[0108] [4] According to one form, the method includes the following steps: when the liquid level of the plating solution in the anode chamber rises, the plating solution in the anode chamber overflows at a height lower than the overflow height of the plating solution in the cathode chamber.

[0109] According to this form, when the liquid level in the anode chamber rises due to some reason (in an emergency), the liquid level in the anode chamber can be kept lower than the liquid level in the cathode chamber, and the diaphragm and the anode can be kept in close contact. For example, even if the plating solution in the cathode chamber flows into the anode chamber due to the deterioration of the diaphragm and the liquid level in the anode chamber rises, the liquid level in the anode chamber can be suppressed to a range lower than the liquid level in the cathode chamber.

[0110] [5] According to one form, the method further includes the following step: not circulating the plating solution in the anode chamber but circulating the plating solution in the cathode chamber.

[0111] According to this form, the consumption of additives can be suppressed by not circulating the plating solution in the anode chamber. When the plating solution is supplied to the cathode chamber and the anode chamber using the same plating solution supply source (storage tank) and circulated, if the plating solution is circulated on the anode side during plating, the expensive additives in the anode chamber continue to be decomposed (consumed). The plating solution is supplied to the anode chamber only when the anode chamber is full, and the plating solution in the anode chamber is not circulated, thereby suppressing the consumption of additives.

[0112] [6] According to one form, the method includes the following steps: introducing a plating solution of the same composition into the anode chamber and the cathode chamber.

[0113] According to this aspect, since the plating solution having the same composition is introduced into the anode chamber and the cathode chamber, the structure for supplying the plating solution can be simplified.

[0114] [7] According to one embodiment, a plating solution having the same composition is introduced into the anode chamber and the cathode chamber from the same plating solution supply source.

[0115] According to this aspect, since the plating solution having the same composition is introduced into the anode chamber and the cathode chamber from the same plating supply source, the structure of the flow path connected to the anode chamber can be simplified.

[0116] [8] According to one embodiment, a plating solution supply source and either a pure water supply source or an electrolyte supply source are selectively connected to the anode chamber.

[0117] According to this aspect, the structure of the flow path connected to the anode chamber can be further simplified.

[0118] [9] According to one form, the method further includes the following steps: detecting the concentration and / or conductivity of the anode chamber by a concentration sensor and / or a conductivity sensor; and issuing an alarm based on a determination result of whether the concentration and / or conductivity has reached a specified threshold.

[0119] According to this form, when the water in the plating solution evaporates in the anode chamber and the concentration and / or conductivity of the plating solution increases, the drop of the liquid level can be detected through the concentration and / or conductivity of the plating solution. That is, in addition to monitoring the liquid level based on the liquid level sensor, the liquid level can also be monitored dually by the concentration sensor and / or the conductivity sensor. Therefore, in the case of a failure of the liquid level sensor, the abnormality of the liquid level can be detected by the concentration sensor and / or the conductivity sensor. As a result, the redundancy of the control of the liquid level management of the anode chamber can be improved.

[0120]

[10] According to one form, after the plating process of the above-mentioned substrate is completed, pure water or electrolyte is supplied to the above-mentioned anode chamber based on the output of the above-mentioned liquid level sensor.

[0121] According to this aspect, it is possible to suppress complication of control during the plating process.

[0122]

[11] According to one embodiment, when it is determined that the liquid level of the plating solution in the anode chamber is lower than a predetermined height, pure water is supplied to the anode chamber.

[0123] According to this aspect, by supplying the reduced amount of pure water in the anode chamber, it is possible to suppress or prevent changes in the concentration of the plating solution in the anode chamber. In addition, it is possible to suppress the cost of the replenished liquid.

[0124]

[12] According to one form, a plating device is provided, comprising: a substrate holder for holding a substrate; an anode arranged opposite to the substrate; a diaphragm arranged in close contact with the upper surface of the anode; a plating tank for holding a plating solution, the plating tank being divided by the diaphragm into a cathode chamber in which the substrate is arranged and an anode chamber in which the anode is arranged, and comprising an exhaust passage connected to the anode chamber and used to discharge bubbles from the anode chamber to the outside of the plating tank; a liquid level sensor arranged in the exhaust passage of the plating tank and detecting whether the height of the liquid level of the plating solution in the exhaust passage is less than a specified height; and a control device for supplying pure water or an electrolyte to the anode chamber in response to the liquid level sensor detecting that the height of the liquid level of the plating solution in the exhaust passage is less than a specified height.

[0125] According to this form, the same effects as those described above in [1] are achieved.

[0126] The above has described the embodiments of the present invention, but the embodiments of the above invention are for easy understanding of the present invention and are not intended to limit the present invention. The present invention can be changed and improved without departing from its main purpose, and it is self-evident that the present invention includes its equivalents. In addition, within the scope of being able to solve at least part of the above-mentioned problems or within the scope of achieving at least part of the effect, any combination of the embodiments and the modified examples can be performed, and the various structural elements recorded in the claims and the specification can be arbitrarily combined or omitted.

[0127] All disclosures of U.S. Patent Application Publication No. 2020-0017989 (Patent Document 1) and International Patent Application No. PCT / JP2022 / 016809 filed on March 31, 2022, including specifications, claims, drawings, and abstracts, are incorporated herein by reference as a whole.

[0128] Description of Reference Numerals

[0129] 10... plating tank; 10a... inner tank; 10b... outer tank; 11... exhaust passage; 11A... overflow passage; 12... liquid level sensor; 13... concentration sensor (conductivity sensor); 20... overflow tank; 31... substrate holder; 41... anode; 41A... through hole; 42... anode holder; 43... anode shield; 51... resistor; 61... air bubble; 71... diaphragm; 72... pressure plate; 72A... through hole; 74 ...fastening member; 75...sealing member; 80...circulation path; 81...storage tank; 82-85...flow path; 86...pump; 87...filter; 88...valve; 89...valve; 90...circulation path; 91...liquid supply source; 92...flow path; 93...valve; 95...flow path; 400...plating module; Ca...anode chamber; Cc...cathode chamber; OFa...overflow surface; OFc...overflow surface; Sa, Sc...liquid surface.

Claims

1. A liquid management method for an anode chamber, characterized in that: The steps include: Preparing a plating tank, the plating tank being provided with an anode and a diaphragm in contact with or in close contact with the upper surface of the anode, and having an upper cathode chamber and a lower anode chamber separated by the diaphragm, and an exhaust passage communicating with the anode chamber and used for exhausting bubbles from the anode chamber to the outside of the plating tank; The plating solution is maintained in the anode chamber and the cathode chamber, and the liquid level of the plating solution in the anode chamber, that is, the liquid level of the plating solution in the exhaust passage is lower than the liquid level of the plating solution in the cathode chamber; determining whether the height of the liquid level of the plating solution in the exhaust passage is less than a predetermined height based on the output of a liquid level sensor disposed in the exhaust passage; and When it is determined that the liquid level of the plating solution in the exhaust passage is lower than a predetermined height, pure water or an electrolyte is supplied to the anode chamber.

2. The method according to claim 1, characterized in that The plating solution is held in the anode chamber, and the liquid level of the plating solution in the anode chamber is set to a height lower than an overflow height of the plating solution in the anode chamber.

3. The method according to claim 1 or 2, characterized in that: Pure water or an electrolyte is supplied to the anode chamber so that the liquid level of the plating solution in the anode chamber becomes a height lower than an overflow height of the plating solution in the anode chamber.

4. The method according to claim 1 or 2, characterized in that: The method comprises the steps of causing the plating solution in the anode chamber to overflow at a height lower than a height at which the plating solution in the cathode chamber overflows when the liquid level of the plating solution in the anode chamber rises.

5. The method according to claim 1 or 2, characterized in that: The method further includes the following step: not circulating the plating solution in the anode chamber, but circulating the plating solution in the cathode chamber.

6. The method according to claim 1 or 2, characterized in that: The method comprises the following steps: introducing a plating solution of the same composition into the anode chamber and the cathode chamber.

7. The method according to claim 6, characterized in that A plating solution having the same composition is introduced into the anode chamber and the cathode chamber from the same plating solution supply source.

8. The method according to claim 7, characterized in that A plating solution supply source and either a pure water supply source or an electrolyte supply source are selectively connected to the anode chamber.

9. The method according to claim 1 or 2, characterized in that: The following steps are also included: The concentration and / or conductivity of the anode chamber is detected by a concentration sensor and / or a conductivity sensor; and an alarm is issued based on a determination result of whether the concentration and / or conductivity reaches a prescribed threshold value.

10. The method according to claim 1 or 2, characterized in that: After the plating process of the substrate is completed, pure water or electrolyte is supplied to the anode chamber based on the output of the liquid level sensor.

11. The method according to claim 1 or 2, characterized in that: When it is determined that the liquid level of the plating solution in the anode chamber is lower than a predetermined height, pure water is supplied to the anode chamber.

12. A plating device, characterized in that: have: a substrate holder that holds the substrate; an anode, arranged facing the substrate; A diaphragm, which is arranged in close contact with the upper surface of the anode; a plating tank for holding a plating solution, the plating tank being divided by the diaphragm into a cathode chamber in which the substrate is arranged and an anode chamber in which the anode is arranged, and having an exhaust passage communicating with the anode chamber for exhausting bubbles from the anode chamber to the outside of the plating tank; a liquid level sensor disposed in the exhaust passage of the plating tank and detecting whether the liquid level of the plating solution in the exhaust passage is less than a predetermined height; as well as A control device supplies pure water or an electrolyte to the anode chamber in response to the liquid level sensor detecting that the height of the liquid level of the plating solution in the exhaust passage is less than a predetermined height.

Images