Plating device and plating method

Abstract

The plating device comprises: a plating tank for holding a plating solution; an anode, which is arranged in the above-mentioned plating tank and has a plurality of through holes; a substrate holder, which holds the substrate in a manner facing the above-mentioned anode; a diaphragm, which is arranged in close contact with the first surface of the above-mentioned anode on the side of the above-mentioned substrate; and a back plate, which is a back plate that is arranged to face the second surface of the above-mentioned anode on the opposite side of the above-mentioned first surface and is separated from the above-mentioned second surface by a specified interval, and regulates the amount of bubbles generated from the above-mentioned anode and accumulated on the above-mentioned second surface.

Description

Technical Field

[0001] The present invention relates to a plating device and a plating method. Background Art

[0002] As a plating device capable of performing plating treatment on a substrate such as a semiconductor wafer, a plating device such as that described in the specification of U.S. Patent Application No. 2020-0017989 (Patent Document 1) is known. The plating device comprises: a plating tank, which stores plating liquid and is provided with an anode; a substrate holder, which holds a substrate as a cathode in a manner arranged opposite to the anode; and a diaphragm, which 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 liquid 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 groove for capturing bubbles is formed between the frame and the diaphragm. In order to prevent such a phenomenon, in the device of the specification of U.S. Patent Application No. 2020-0017989 (Patent Document 1), the supply of plating liquid to the anode chamber is adjusted in a manner that the pressure in the anode chamber is higher than that in the cathode chamber, so as to prevent the diaphragm from extending downward.

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

[0004] In the plating device, there is a possibility that bubbles of gas such as oxygen generated at the anode accumulate unevenly on the substrate, diaphragm, etc., the ion conduction resistance (resistance) of the bubble accumulation portion increases, and the uniformity of the distribution of the plating film thickness deteriorates. For example, there is a possibility that bubbles accumulate on the plated area of ​​the substrate, making the formation of the plating film on the substrate unstable. In addition, there is a possibility that bubbles accumulate on the diaphragm, and the accumulated bubbles become a resistance component, making the plating unstable. In addition, in the case where a resistor body plate with a porous structure is arranged near the substrate, there is a possibility that bubbles accumulate on the resistor body plate, and the accumulated bubbles become a resistance component, making the plating unstable.

[0005] Furthermore, there is a fear that the gas generated at the anode (eg, active oxygen) reacts with the additive in the plating solution to deteriorate the additive.

[0006] In the specification of U.S. Patent Application No. 2020-0017989 (Patent Document 1), there is no description of the influence of the gas generated at the anode on plating. Summary of the invention

[0007] The present invention has been made in view of the above circumstances, and one of its objects is to suppress the influence of bubbles generated at an anode on the uniformity of the plated film thickness distribution in a plating apparatus.

[0008] According to one aspect of the present invention, there is provided a plating device comprising: a plating tank for holding a plating solution; an anode, which is arranged in the above-mentioned plating tank and has a plurality of through holes; a substrate holding frame, which holds the substrate in a manner facing the above-mentioned anode; a diaphragm, which is arranged in close contact with the first surface of the above-mentioned anode on the side of the above-mentioned substrate; and a back plate, which is the back plate facing the second surface of the above-mentioned anode on the opposite side of the above-mentioned first surface and is arranged to be separated from the above-mentioned second surface at a specified interval, and regulates the amount of bubbles generated from the above-mentioned anode and accumulated on the above-mentioned second surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a perspective view showing the overall structure of a plating apparatus according to one embodiment.

[0010] Figure 2 It is a plan view showing the overall structure of a plating apparatus according to one embodiment.

[0011] Figure 3 This is a cross-sectional view for explaining the structure of a plating module according to one embodiment.

[0012] Figure 4 This is a schematic diagram of the anode chamber of the plating module as viewed from below.

[0013] Figure 5 This is an enlarged cross-sectional view near the anode.

[0014] Figure 6 It is a cross-sectional view showing the fixing structure of the anode from the diaphragm side.

[0015] Figure 7 It is a cross-sectional view showing the structure for fixing the separator to the anode.

[0016] Figure 8 It is a cross-sectional view for explaining the structure of the plating module according to the second embodiment.

[0017] Fig. 9 This is a photo of the plating module (without diaphragm) used in the experiment.

[0018] Fig.10 This is a photo of the plating module (with diaphragm) used in the experiment.

[0019] Fig.11A The following are photos showing the assembly procedure of the plating module (with a diaphragm) used in the experiment.

[0020] Fig. 11B The following are photos showing the assembly procedure of the plating module (with a diaphragm) used in the experiment.

[0021] Fig. 11CThe following are photos showing the assembly procedure of the plating module (with a diaphragm) used in the experiment.

[0022] Fig.11D The following are photos showing the assembly procedure of the plating module (with a diaphragm) used in the experiment.

[0023] Fig.11E The following are photos showing the assembly procedure of the plating module (with a diaphragm) used in the experiment.

[0024] Fig.12 This is a schematic cross-sectional view of the plating module (with a diaphragm) used in the experiment.

[0025] Fig.13 It is the measurement result of the anode voltage during plating.

[0026] Fig.14A This is a photograph of a plating module (without a diaphragm) before plating.

[0027] Fig. 14B is a photograph of the plating module (without diaphragm) during plating.

[0028] Fig.15A This is a photo of a plating module (with a diaphragm) before plating.

[0029] Fig. 15B is a photo of the plating module (with diaphragm) during plating.

[0030] Fig.16A This is a schematic diagram for explaining the movement of bubbles generated from the anode.

[0031] Fig. 16B This is a schematic diagram for explaining the movement of bubbles generated from the anode.

[0032] Fig.17A It is a cross-sectional view showing the structure near the anode of the plating module according to the third embodiment.

[0033] Fig. 17B It is a cross-sectional view showing the structure near the anode of the plating module according to the third embodiment.

[0034] Fig.18 This is a bottom view of the structure near the anode of the plating module according to the third embodiment as seen from below.

[0035] Fig.19 It is a top view and a cross-sectional view of the bubble adjustment plate according to the third embodiment.

[0036] Fig. 20 This is a schematic diagram for explaining the discharge of bubbles on the back side of the anode.

[0037] Fig.21AIt is a cross-sectional view showing the structure near the anode of the plating module according to the fourth embodiment.

[0038] Fig.21B It is a cross-sectional view showing the structure near the anode of the plating module according to the fourth embodiment.

[0039] Fig. 22 This is a bottom view of the structure near the anode of the plating module according to the fourth embodiment as seen from below.

[0040] Fig.23 This is a schematic diagram for explaining the discharge of bubbles on the back side of the anode.

[0041] Fig.24 It is a cross-sectional view showing the structure near the anode of a plating module according to a modified example.

[0042] Fig.25 This is a bottom view of the structure near the anode of the plating module according to the modification example as seen from below.

[0043] Fig.26 1 and 1 are a plan view and a cross-sectional view of a bubble adjustment plate according to a modified example. DETAILED DESCRIPTION

[0044] 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).

[0045] (First embodiment)

[0046] 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 .

[0047] 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 carrying substrates out of the plating device 1000 to the 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-wet module 200 and the spin cleaning dryer 600. The transport robot 110 and the transport device 700 transfer substrates between the transport robot 110 and the transport device 700, and the substrates can be transferred via a temporary placement table (not shown).

[0048] 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 treatment liquid such as pure water or degassed water, thereby replacing the air inside the pattern formed on the surface of the substrate with the treatment liquid. The pre-wet module 200 replaces the treatment 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.

[0049] 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.

[0050] 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 with an operator.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] [Plating Module]

[0056] 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.

[0057] 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 schematic diagram of the anode chamber of the plating module as viewed from below.

[0058] The plating device 1000 of 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 of 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 a lifting mechanism (not shown) that rotate, tilt, and lift the substrate holder 31. In addition, an overflow tank 20 can also be provided outside the plating tank 10.

[0059] The plating tank 10 is composed of a bottomed container with an opening at the top. The plating tank 10 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 has a cylindrical internal space for storing a plating solution. As a plating solution, any solution containing ions of metal elements constituting a plating film can be used, and its specific example is not particularly limited. In the present embodiment, as an example of a plating process, a copper plating process is used, and as an example of a plating solution, a copper sulfate solution is used. In addition, in the present 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 inside of the plating tank 10 is divided into an anode chamber Ca and a cathode chamber Cc by a diaphragm 71, and the plating solution Pa of the anode chamber Ca and the plating solution Pc of the cathode chamber Cc can be the same or different. For example, in the plating solution Pa of the anode chamber Ca and the plating solution Pc of the cathode chamber Cc, the presence or absence of additives and the concentration can be the same or different.

[0060] The overflow tank 20 is composed of a bottomed container disposed outside the plating tank 10. The overflow tank 20 temporarily stores the plating solution that exceeds the upper end of the plating tank 10. In one example, the plating solution in the overflow tank 20 is discharged from a discharge port (not shown) for the overflow tank 20, temporarily stored in a storage tank (not shown), and then returned to the plating tank 10 again. Figure 3 In the example, the overflow weir 10c for causing the plating solution to overflow from the cathode chamber Cc to the overflow tank 20 and the overflow weir 10a for causing the plating solution to overflow from the anode chamber Ca to the overflow tank 20 are set to approximately the same height.

[0061] 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.

[0062] 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 that has an opening portion that exposes the anode 41, and adjusts the electric field from the anode 41 toward the substrate Wf by adjusting the exposure range of the anode 41 through the opening portion. The anode shield 43 may also be an anode shield with 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.

[0063] 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.

[0064] 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.

[0065] 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 other 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 is easily discharged from the through hole to the back of the anode 41, the thickness of the anode 41 is preferably about 0.5 mm to 3 mm. The shape and size of the through hole are also not particularly limited, but from the perspective of ease of processing and stability of voltage during plating, the size of the opening (diameter in the case of a circle, 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 called an anode pressing plate. A diaphragm 71 (Nafion (registered trademark), porous membrane, etc.) having ion permeability that can be penetrated and wetted by the plating liquid is bonded or closely attached to the front surface of the anode 41 (the surface close to the cathode / substrate side, the upper surface in this example). In the present embodiment, the interior of the plating tank 10 is separated into an anode chamber Ca and a 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 anode surface. 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 adopted.

[0066] 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, 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 discharge port 11 ( Figure 3 , Figure 4 ) and discharged to the outside of the plating tank 10.

[0067] 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 is 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.

[0068] 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.

[0069] 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 at 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.

[0070] In the present embodiment, in the plating tank 10, a gas discharge port 11 is provided outside the diaphragm 71 (see Figure 3 , Figure 4 ).like Figure 3 As shown, the bubbles 61 that move to the back side of the anode 41 are discharged from the discharge port 11 to the outside of the plating tank 10. In this structure, the bubbles 61 generated at the anode 41 can be naturally discharged through the exhaust port 11, and there is no need to circulate the plating solution in the anode chamber Ca to discharge the bubbles. In addition, the plating solution in the anode chamber Ca can also be circulated. Thus, the discharge of the bubbles in the anode chamber Ca can be further promoted. In this case, the excessive and uneven accumulation of oxygen on the lower side of the anode 41 is suppressed, thereby promoting the discharge of bubbles (oxygen) in the through hole 41A of the anode 41, which can further improve the uniformity of the plating film. The circulation of the plating solution in the anode chamber Ca can be constructed in the same manner as the circulation path 80 of the plating solution in the cathode chamber Cc. Among them, it is connected so that the plating solution discharged from the anode chamber Ca returns to the anode chamber Ca again.

[0071] In addition, in this embodiment, if Figure 4 As shown in FIG. 4 , a notch 42A is provided on the lower surface of the anode holder 42. The notch 42A may be formed so that the height of the anode holder 42 becomes lower in the portion of the notch 42A, or may be formed so that the anode holder 42 is discontinuous in the portion of the notch 42A. Figure 6 and Figure 7 As shown, in the case of a structure in which the lower part of the anode holder 42 protrudes downward than the back side of the anode 41, the bubbles 61 accumulated on the back side of the anode 41 can easily pass through the notch 42 and move toward the discharge port 11. The notch 42 is preferably arranged near the discharge port 11 or at a position facing the discharge port 11. Among them, the notch 42A may not be provided on the anode holder 42. The notch 42A and the discharge port 11 may also be formed in multiple numbers around the anode 41. In addition, in order to easily discharge the bubbles 61, the anode 41 itself can also be arranged to be inclined obliquely than the horizontal. In this case, the notch 42 is preferably arranged above the center of the anode.

[0072] Figure 6 and Figure 7 4 is a cross-sectional view showing 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 In the embodiment, the pressure plate 72 is omitted ( Figure 6 )、Press ring 73( Figure 7 ).

[0073] Figure 6 In the example of , the diaphragm 71 is pressed against the surface of the anode 41 on the substrate side 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 (for example, 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.

[0074] Figure 7In 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 75 that bonds the diaphragm 71 to the anode 41 has ion permeability. For example, it can be a resin having an ion replacement 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 and fixed relative to the anode holder 42 by the pressure ring 73. In addition, a sealing member 75 (for example, an O-ring) that seals therebetween is provided between the pressure ring 73 and the diaphragm 71. 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.

[0075] (Second embodiment)

[0076] Figure 8 It is a cross-sectional view for explaining the structure of the plating module involved in the second embodiment. Hereinafter, the difference from the above embodiment will be mainly explained, and the explanation of the structure identical to the above embodiment will be omitted. In the present embodiment, it is configured that the lowest part of the side wall of the cathode chamber Cc of the plating tank 10 is slightly higher than the lowest part of the side wall of the discharge port 11. Thus, the overflow surface Sc of the cathode chamber Cc of the plating tank 10 is set to be slightly higher (to a degree that the liquid movement through the diaphragm is minimized) than the overflow surface Sa of the anode chamber Ca (discharge port 11). In addition, the discharge port 11 is connected to the anode chamber Cc, so the overflow surface Sa of the discharge port 11 becomes the overflow surface of the anode chamber Ca. In the figure, the difference between the overflow surface Sc and the overflow surface Sa is represented by h1. In this structure, as shown by arrows A3 and A2 in the figure, by slightly pressurizing the cathode chamber Cc relative to the anode chamber Ca, the diaphragm 71 can be improved to be close to the anode 41.

[0077] The plating tank 10 is provided with an overflow dam 10c, which allows the plating solution to overflow from the cathode chamber Cc to the outside of the plating tank 10. In this example, the overflow dam 10c is a side wall of the cathode chamber Cc between the cathode chamber Cc and the overflow tank 20 of the plating tank 10. In addition, the plating tank 10 is provided with an overflow dam 10a, which allows the plating solution to overflow from the anode chamber Ca to the outside of the plating tank 10. In this example, the overflow dam 10a is a side wall between the discharge port 11 of the plating tank 10 and the overflow tank 20 (a side wall of the discharge port 11 of the plating tank 10). By setting the height (overflow surface Sc) of the overflow dam 10c higher than the height (overflow surface Sa) of the overflow dam 10a, a pressure difference is generated between the cathode chamber Cc and the anode chamber Ca (pressure in the cathode chamber Cc>pressure in the anode chamber Ca). The pressure difference between the cathode chamber Cc and the anode chamber Ca, that is, the height of each overflow weir 10c, 10a is set to minimize the liquid movement through the diaphragm 71 (or to prevent excessive liquid movement through the diaphragm 71). The other structures are the same as those in the above embodiment, and therefore, the description thereof is omitted.

[0078] In addition, in the above-mentioned embodiment and the present embodiment, if Figure 8 As shown in FIG. 1 , a circulation path 80 may be provided for circulating the plating solution recovered in the overflow tank 20 in the cathode chamber Cc by a pump 81. One or more storage units may be provided in the middle of the circulation path 80.

[0079] [Experimental example of plating module]

[0080] An experimental example 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.12 Schematically shows Fig.10 A cross section of an experimental plating module (with diaphragm) is shown. Fig. 9 In the plating tank 10 that holds the plating solution, an anode 41 and a cathode 32 (corresponding to the substrate Wf) separated upward from the anode 41 by a predetermined interval are arranged. 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 by a predetermined interval are arranged. Fig.12 ) is connected to the positive terminal of the power source 95, and the cathode 32 is connected to the negative terminal of the power source 95. Fig.12 middle, Fig. 9 The structure omits the diaphragm 71 and the pressure plate 72.

[0081] Fig.12In the figure, reference numeral 95 indicates a power source for applying voltage between the anode and cathode, and reference numerals 91 and 92 indicate clamping pieces. As shown in the figure, in the experimental plating module (with a diaphragm), in the plating tank 10, the anode 41, the diaphragm 71 and the pressing plate 72 are closely attached to each other by the clamping parts 91 and 92, and the cathode 32 is arranged upwardly and separated from the pressing plate 72 at a predetermined interval. In addition, Fig.12 In the embodiment, the diaphragm 71 and the pressure plate 71 are omitted, but Fig. 9 The plating modules (without diaphragms) used in the experiments shown are generally identical.

[0082] Figures 11A to 11E Shown are photographs illustrating the assembly procedure of an experimental plating module (with a diaphragm). Fig.11A In the embodiment, the anode 41 is arranged on a pair of clamping pieces 91. The anode 41 and the clamping pieces 91 are fixed by, for example, tape or the like. Fig. 11B In the embodiment, the diaphragm 71 is arranged on the upper surface of the anode 41 . Fig. 11C In the embodiment, a pressure plate 72 is arranged on the diaphragm 71 . Fig.11D In the embodiment, a pair of clamping pieces 92 are arranged on the pressing plate 72, and the clamping pieces 91 and the clamping pieces 92 are fixed by using tape or the like, thereby the anode 41, the diaphragm 71 and the pressing plate 72 are clamped and fixed by the clamping pieces 91 and 92. Fig.11E Observed from below Fig.11D Afterwards, Fig.10 As shown, cathode 32 is arranged to be separated upward from platen 72. Cathode 32 is separated from platen 72 by buoyancy generated by the plating solution, but cathode 32 may be arranged on a spacer or the like to be separated from platen 72 as appropriate.

[0083] In addition, if Fig. 9 As shown, the experimental plating module (without diaphragm) is configured with an anode 41 in a plating tank 10, and a cathode 32 is configured in a manner separated upward from the anode 41. The cathode 32 is separated from the pressing plate 72 due to the buoyancy generated by the plating solution, but the cathode 32 may be appropriately configured above a spacer and the like to be separated from the pressing plate 72.

[0084] The 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.

[0085] Anode: IrO2 / Ti iron mesh (metal mesh)

[0086] Cathode: Pt / Ti iron mesh (metal mesh)

[0087] Membrane: Yumicron Y-9207TA (micro-porous membrane) (YUASA Membrane Systems CO., Ltd.)

[0088] Electrolyte: 100g / L-H2SO4

[0089] Anode area: 0.24dm 2 (60mm×40mm)

[0090] Current density: 5ASD

[0091] Fig.13 It is the measurement result of the anode voltage during plating. As shown in the measurement result, it can be known 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 the case without the diaphragm. According to the result, even if the diaphragm 71 is closely attached to 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.

[0092] Fig.14A This is a photograph of a plating module (without a diaphragm) before plating. Fig. 14B 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.

[0093] Fig.15A This is a photo of a plating module (with a diaphragm) before plating. Fig. 15B 1 and 2 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.

[0094] Fig.16A and Fig. 16BIt is a schematic diagram for explaining the movement of bubbles generated from the anode. As mentioned above, there is a situation where if bubbles accumulate on the back side of the anode 41 (the surface on the side away from the substrate), the voltage of the anode 41 changes due to the bubbles. In particular, using Nafion (registered trademark) as an ion exchange membrane as a diaphragm has a tendency to be particularly prominent when plating at a high current density. As its reasons, the following two points are considered. The first reason is that the bubbles accumulated on the back side of the anode 41 block the electric field that is wound into the back side of the anode. This reason also occurs when the diaphragm is not close to the front surface of the anode (the surface on the substrate side), and it can be considered that the influence on the voltage change of the anode caused by this reason is small. As the second reason, due to the buoyancy of the bubbles accumulated on the back side of the anode, the pressure of the plating solution (including bubbles) in the anode through-hole increases, and the pressure of the plating solution near the anode surface (the inner wall and back side of the through-hole) increases, the saturated dissolved oxygen concentration in the plating solution increases, and the electrode potential of the anode increases.

[0095] like Fig.16A As shown in FIG. 1 , the bubbles 61 generated by the anode 41 form a layer or mass of bubbles 61 (hereinafter referred to as the bubble layer) on the back side of the anode 41. In this state, the pressure of the plating solution (including bubbles) in the through hole 41A becomes high due to the buoyancy generated by the bubble layer on the back side of the anode. Fig. 16B As shown by the dotted line, the bubble layer partially leaves the back of the anode 41 and is discharged toward the discharge port 11. Then, for the portion (the dotted line portion) where the bubble layer partially leaves the back of the anode 41, a state where there is no bubble layer on the back of the anode temporarily occurs, and the plating solution (including bubbles) in the anode through-hole is released by the buoyancy generated by the bubble layer on the back. As a result, the pressure of the plating solution in the anode through-hole decreases, and the saturated dissolved oxygen concentration near the anode surface (the inner wall of the through-hole, the back) decreases, and the electrode potential of the anode 41 also decreases. Thereafter, a bubble layer is formed again at the dotted line portion. However, if the pressure of the plating solution near the anode surface (the inner wall of the through-hole, the back) changes in this way, the saturated dissolved oxygen concentration near the anode surface changes, and the voltage of the anode 41 changes, and there is a possibility that the in-plane uniformity of the plating film thickness is reduced.

[0096] (Third embodiment)

[0097] Fig.17A , Fig. 17B and Fig.18 FIG. 2 shows the structure near the anode of the plating module according to the third embodiment. Fig.18 This is a bottom view of the structure near the anode as seen from below. Fig.17A It is along Fig.18 The AA cross-sectional view, Fig. 17B It is along Fig.18 A cross-sectional view of the BB. Fig.19 The following mainly describes the differences from the above-mentioned embodiment, and omits description of the same structures as the above-mentioned embodiment.

[0098] In this embodiment, if Fig.17A and Fig. 17B As shown in FIG. 1 , a bubble adjustment plate 140 (also referred to as a back plate) is disposed below the anode 41 at a predetermined interval (for example, 5 mm or less, more preferably 2 mm or less). Fig.19 As shown, the bubble adjustment plate 140 has the same shape as the anode 41 (circular in this example) and has a larger diameter than the anode 41 so as to cover the entire back side of the anode 41. A through hole 141 for passing the power supply protrusion 44 is provided in the center of the gas adjustment plate 140. Fig.17A and Fig. 17B As shown, a spacer 130 is provided between the anode 41 and the bubble adjustment plate 140 for adjusting the interval therebetween. Fig.19 As shown, the spacer 130 may also be pre-installed and arranged on the upper surface of the bubble adjustment plate 140 by, for example, an adhesive or the like. The spacer 130 includes: a plurality of circumferential spacers 131 evenly arranged on the outer periphery of the bubble adjustment plate 140; and a plurality of radial spacers 132, which are integrally provided with a portion of the circumferential spacers 131 or are installed and provided on a portion of the circumferential spacers 131. In this example, a radial spacer 132 is provided for every other circumferential spacer 131. The radial spacer 132 may also be integrally provided with the circumferential spacer 131 or be connected to or contacted with the circumferential spacer 131.

[0099] In this embodiment, if Fig. 17B and Fig.18 As shown, the anode holder 42 has an annular upper anode pressing portion 42B; and a plurality of lower anode pressing portions 42C are arranged along the circumference of the anode pressing portion 42B. The upper anode pressing portion 42B is integrally provided with the side wall of the plating tank 10 or is mounted on the side wall of the plating tank 10. The upper anode pressing portion 42B abuts against the outer peripheral portion of the upper surface of the anode 41 to press the anode 41. The diaphragm 71, the seal 75 and the pressing plate 72 are fixed to the upper surface of the upper anode pressing portion 42B by the fastening member 74. That is, the pressing plate 72 is fixed to the upper anode pressing portion 42B in a state where the diaphragm 71 and the seal 75 are pressed. A plurality of lower anode pressing portions 42C are fixed to the lower surface of the upper anode pressing portion 42B by the fastening member 71A. Each lower anode pressing portion 42C is provided corresponding to the circumferential spacer 131.

[0100] The upper anode pressing part 42B and the lower anode pressing part 42C are fixed in such a manner that the anode 41, the spacer 130, and the bubble adjustment plate 140 are sandwiched from above and below. More specifically, each lower anode pressing part 42C is fixed to the upper anode pressing part 42B by the fastening member 74A in such a manner that the lower anode pressing part 42C and the upper anode pressing part 42B sandwich the gas adjustment plate 140 and the circumferential spacer 131, thereby sandwiching and fixing the anode 41 and the radial spacer 132 between the upper anode pressing part 42B and the gas adjustment plate 140. In the state where the bubble adjustment plate 140 is installed near the anode 41 as described above, Fig. 17B As shown, radial spacers 132 and circumferential spacers 131 are respectively arranged between the bubble adjustment plate 140 and the anode 41 and the upper anode pressing portion 42B, whereby the interval between the anode 41 and the bubble adjustment plate 140 is set according to the radial spacers 132 .

[0101] For the portion of the bubble adjustment plate 140 where the circumferential spacer 131 is not provided ( Fig.19 For the area of ​​the bubble adjustment plate 140 between the circumferential spacers 131, as Fig.17A As shown, the space between the anode 41 and the gas regulating plate 140 is open to the radial outside.

[0102] Fig. 20 Schematic diagram for explaining the discharge of bubbles on the back side of the anode in the third embodiment. According to the present embodiment, there is a bubble adjustment plate 140 on the back side of the anode 41. Therefore, as shown in the figure, the accumulation of bubbles 61 on the back side of the anode 41 is limited to the space between the anode 41 and the bubble adjustment plate 140. Therefore, the accumulation of bubbles on the back side of the anode 41 is small (the thickness of the bubble 61 layer is limited). Fig. 20 As shown in the dotted line portion of the figure below, the bubbles 61 are separated from the anode 41 and discharged, and the change in the amount of bubble accumulation on the back side of the anode 41 is also small. Fig. 20 As shown, the detachment of bubbles is likely to occur outside the back side of the anode 41. Therefore, by suppressing the pressure change near the anode surface (inner wall of the through hole, back side), suppressing the saturated dissolved oxygen concentration in the plating solution near the anode surface (inner wall of the through hole, back side), and further suppressing the change of the electrode voltage of the anode, it is possible to suppress the reduction of the in-plane uniformity of the plating film thickness. From the viewpoint of reducing the accumulation of bubbles on the back side of the anode 41, the interval between the anode 41 and the bubble adjustment plate 140 (equivalent to the thickness of the radial spacer 132) is preferably smaller than the height of the bubbles accumulated on the back side of the anode 41 when the bubble adjustment plate 140 is not provided. The height of the bubbles formed varies depending on the surface tension and specific gravity of the plating solution used, but the interval between the anode 41 and the bubble adjustment plate 140 is preferably approximately 5 mm or less, and more preferably 2 mm or less.

[0103] In addition, the space between the circumferential spacer 131 and / or the radial spacer 132 is evenly arranged in the circumferential direction, so that the bubbles 61 on the back side of the anode 41 are evenly discharged in the circumferential direction. Therefore, the bubbles on the back side of the anode 41 can be evenly separated from the anode 41, and the variation of the bubble accumulation amount can be further suppressed. In addition, the unevenness of the bubble accumulation amount in each part of the back side of the anode can also be suppressed. A plurality of discharge ports 11 can also be provided. For example, the discharge port 11 can also be provided according to the area between each adjacent radial spacer 132.

[0104] Furthermore, the space between the anode 41 and the gas adjustment plate 140 is appropriately divided by the plurality of radial spacers 132 arranged in a balanced manner, thereby suppressing the detachment of large bubbles.

[0105] (Variation Example)

[0106] In the above-mentioned embodiment, the spacer 130 (131, 132) is in the shape of a quadrangular prism, but the shape and size of the spacer are not particularly limited as long as it is a shape and size that can form a specified interval (gap) between the anode 41 and the bubble adjustment plate 140 and does not hinder the discharge of bubbles. For example, the spacer can also be in the shape of a cylinder, a triangular prism and / or a disc. In addition, a pin-shaped spacer can also be used, which forms a specified gap between the anode and the bubble adjustment plate by passing through the bubble adjustment plate 140 and abutting against the back of the anode 41 (described later). In addition, the anode 41 and the bubble adjustment plate 140 have sufficient flatness, and in the case where the specified gap can be formed without using the spacer 132 and the spacer 132A (described later), these spacers themselves can also be omitted.

[0107] Fig.24 and Fig.25 FIG. 2 shows the structure near the anode of the plating module according to the modification example. Fig.25 This is a bottom view of the structure near the anode as seen from below. Fig.24 It is along Fig.25 AA cross-sectional view. Fig.26The top view and cross-sectional view of the bubble adjustment plate are shown. The following mainly describes the differences from the above-mentioned embodiment, and the description of the same structure as the above-mentioned embodiment is omitted. As shown in these figures, in the modified example, the radial spacer 132 in the above-mentioned embodiment is replaced by a pin-shaped spacer 132A. The pin-shaped spacer 132A is, for example, a screw-shaped spacer, which has a thread on the side, and has a flat or curved end 132B that abuts against the back of the anode 41, and has a thread head 132C on the base end side. In this modified example, the bubble adjustment plate 140 is threaded to form a through hole (threaded hole) 140A, and the pin-shaped spacer 132A is screwed in from the lower side of the through hole 140A and protrudes upward, and the end of the pin-shaped spacer 132A abuts against the back of the anode 41, thereby forming a specified interval (gap) between the anode 41 and the bubble adjustment plate 140. In other examples, instead of forming threads on the pin-shaped spacer 132A and the bubble adjustment plate 140 , the pin-shaped spacer 132A may be fixed to the bubble adjustment plate 140 by other means.

[0108] (Fourth embodiment)

[0109] Fig.21A , Fig.21B and Fig. 22 FIG. 2 shows the structure near the anode of the plating module according to the third embodiment. Fig. 22 This is a bottom view of the structure near the anode as seen from below. Fig.21A It is along Fig. 22 The AA cross-sectional view, Fig.21B It is along Fig. 22 A cross-sectional view of the BB. Fig.23 Schematic diagram for explaining the discharge of bubbles on the back surface of the anode. Hereinafter, the differences from the above embodiment will be mainly explained, and the explanation of the same structure as the above embodiment will be omitted.

[0110] In this embodiment, if Fig.21A , Fig.21B and Fig. 22 As shown, a bubble buffer ring 150 is arranged to surround the anode 41 from all sides, and the bubble buffer ring 150 has a plurality of small diameter portions 151 and a plurality of large diameter portions 152 with a rectangular cross section. Fig. 22 As shown in FIG. 1 , the small diameter portion 151 and the large diameter portion 152 are alternately arranged along the circumferential direction of the bubble buffer ring 150. Fig.21A and Fig.21BAs shown, the small diameter portion 151 is formed to have a smaller width (radial dimension) and thickness (height dimension) than the large diameter portion 152. The lower end surface 151A of the small diameter portion 151 is located at a higher position than the lower end surface 152A of the large diameter portion 152, and the height difference between the lower end surface 151A of the small diameter portion 151 and the back surface of the anode 41, that is, the gap G1, determines the thickness of the layer of bubbles 61 accumulated on the back surface of the anode 41 (refer to Fig.23 ). The layer of bubbles 61 accumulated on the back of the anode 41 exceeds the gap G1 and exceeds the lower end surface 151A of the small diameter portion 151 of the bubble buffer ring 150, and is separated and discharged radially outward. The upper end surface 151B of the small diameter portion 151 is located below the upper end surface 152B of the large diameter portion 152, and a gap G2 is formed between the anode pressing portion 42D and the upper end surface 152A of the small diameter portion 151. The gap G2 is a gap for the plating solution to invade, and has the function of allowing the plating solution to invade the anode 41 side. The anode pressing portion 42D can have the same structure as the upper anode pressing portion 42B described above.

[0111] like Fig. 22 As shown, a plurality of pressing part members 42E fixed to the annular anode pressing part 42D are arranged along the circumference of the anode pressing part 42D. Each pressing part member 42E is arranged corresponding to the large diameter portion 152 of the bubble buffer ring 150. In the example shown in the figure, each pressing part member 42E is arranged at the center of the circumferential long side direction of the large diameter portion 152. In a state where the large diameter portion 152 of the bubble buffer ring 150 is clamped by the anode pressing part 42D and the pressing part member 42E, the anode pressing part 42D and the pressing part member 42E are fixed by the fastening member 74A. Thus, the bubble buffer ring 150 is installed in the plating tank 10 in a manner of surrounding the anode 41 from all sides. The anode 41 is arranged at a predetermined height below the power supply protrusion 44 by a member such as a spacer not shown, and the outer periphery of the anode 41 is pressed from above by the anode pressing part 42D, thereby being clamped and fixed from above and below.

[0112] Fig.23 FIG. 2 is a schematic diagram for explaining the discharge of bubbles from the back side of the anode in the fourth embodiment. According to the present embodiment, the bubbles 61 accumulated on the back side of the anode 41 beyond the lower end surface 151A of the small diameter portion 151 of the bubble buffer ring 150 are partially discharged as shown in FIG. Fig.23As shown by the dotted line in the lower part of the figure, the bubbles 61 exceed the lower end of the small diameter portion 151 and are detached and discharged radially outward. In this structure, there is a possibility that the bubbles 61 detach from the lower end surface 151A of the small diameter portion 151 of the bubble buffer ring 150, and the amount of bubbles detached at one time is expected to become slightly larger, but a layer or block of bubbles 61 is always accumulated on the back of the anode 41 as a whole, so that the pressure fluctuation near the anode surface (the inner wall of the through hole, the back) can be suppressed. As a result, the saturated dissolved oxygen concentration in the plating solution near the anode surface (the inner wall of the through hole, the back) can be suppressed, and the fluctuation of the electrode voltage of the anode can be suppressed, and the reduction of the in-plane uniformity of the plating film thickness can be suppressed.

[0113] According to the above-described embodiment, at least the following effects are achieved.

[0114] (1) 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 effectively ensuring the ion conduction path between the anode and the substrate. Therefore, it is possible to suppress the generation of ion conduction resistance caused by bubbles from the anode on the ion conduction path between the anode and the substrate, stably perform plating on the substrate, and improve the uniformity of the plating film thickness.

[0115] (2) According to the above embodiment, an insoluble anode can be used as the anode, the maintainability of the anode is improved, and the running cost can be reduced.

[0116] (3) According to the above embodiment, the gas generated by the anode can be naturally discharged without circulating the plating solution in the anode chamber, thereby simplifying the structure and / or operation of the plating tank. In addition, the plating solution in the anode chamber can be circulated to further promote the discharge of bubbles.

[0117] (4) 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, and the change of the electrode voltage of the anode can be suppressed, and the reduction of the in-plane uniformity of the plating film thickness can be suppressed.

[0118] [Modifications]

[0119] In the above description, a face-down plating module is taken as an example, but the present invention can also be applied to a face-up plating module in which plating is performed with the surface to be plated of the substrate facing upward.

[0120] At least the following aspects can be understood from the above-mentioned embodiments.

[0121] [1] According to one aspect, a plating device is provided, comprising: a plating tank for holding a plating solution; an anode disposed in the plating tank and having a plurality of through holes; a substrate holder for holding a substrate in a manner facing the anode; a diaphragm disposed in close contact with a first surface of the anode on the substrate side; and a back plate, which is disposed facing a second surface of the anode on the opposite side of the first surface and separated from the second surface by a predetermined interval, and adjusts the amount of bubbles generated from the anode and accumulated on the second surface. The distance between the back plate and the anode is set to a short distance (e.g., 5 mm or less, more preferably 2 mm or less) that makes the amount of bubbles accumulated on the second surface of the anode sufficiently small, so as to prevent the electrode potential of the anode from changing due to the detachment of bubbles accumulated on the second surface of the anode.

[0122] According to this form, the diaphragm is closely attached to the surface of the anode having a plurality of through holes on the substrate side, so that bubbles of gas generated by the anode are suppressed from moving toward the substrate side through the diaphragm and from passing through the plurality of through holes of the anode to the second surface side of the anode. In addition, the diaphragm is closely attached to the anode, so that the bubbles are suppressed from accumulating between the anode and the diaphragm. As a result, the bubbles are suppressed from accumulating in the ion conduction path between the anode and the substrate.

[0123] On the other hand, since cations can move through the separator, an ion conduction path between the anode and the substrate can be ensured, and an electrode reaction in the substrate can be stably performed.

[0124] As a result, it is possible to suppress the accumulation of bubbles on the ion conduction path between the anode and the substrate, and to ensure the ion conduction path between the anode and the substrate to stably perform the plating of the substrate, and to improve the uniformity of the distribution of the plating film thickness. In other words, it is possible to solve the following problem: when the diaphragm is arranged away from the anode as in the past, bubbles from the anode accumulate on the diaphragm on the ion conduction path, which has a negative impact on the uniformity of the distribution of the plating film thickness.

[0125] In addition, according to this form, since there is a back plate on the second surface side of the anode, the thickness of the bubbles on the second surface of the anode can be limited to within the distance between the anode and the back plate. As a result, the accumulation of bubbles on the second surface of the anode can be reduced, and the change in the accumulation of bubbles accompanying the discharge of bubbles on the second surface of the anode can be suppressed. The pressure change of the plating solution near the second surface of the anode can be suppressed, and thus the change of the electrode potential in the anode can be suppressed.

[0126] [2] According to one form, there is further provided a radial spacer, the radial spacer being provided between the back plate and the anode and being arranged in plurality along the circumference of the anode, each radial spacer extending in the radial direction between the center and the outer periphery of the back plate.

[0127] According to this form, the distance between the back plate and the anode can be adjusted by a radial spacer. In addition, the distance between the anode and the back plate is maintained by a plurality of radial spacers extending in the radial direction, so that the deflection of the anode and the back plate can be suppressed, and the distance between the anode and the back plate can be correctly adjusted throughout the entire anode. In addition, the bubbles accumulated on the second surface of the anode can be guided radially outward by the radial spacer. If a plurality of radial spacers are arranged at balanced intervals throughout the entire circumference of the anode, the bubbles can be discharged radially outward in a balanced manner throughout the entire circumference of the anode.

[0128] [3] According to one form, it further comprises: an anode pressing portion that presses the outer peripheral portion of the first surface of the anode; and a circumferential spacer that is provided between the back plate and the anode pressing portion and is arranged in plurality along the circumference of the anode.

[0129] According to this form, by maintaining the distance between the anode pressing portion and the back plate at a desired distance, the installation of the back plate can be stabilized. In addition, by distributing a plurality of circumferential spacers, it is possible to ensure space for discharging bubbles between the circumferential spacers. If a plurality of circumferential spacers are arranged at even intervals around the entire circumference of the anode, bubbles can be evenly discharged radially outwards around the entire circumference of the anode.

[0130] [4] According to one embodiment, the radial spacer is provided every other circumferential spacer among the plurality of circumferential spacers.

[0131] According to this aspect, the distance between the anode and the rear plate can be maintained with high accuracy without excessively blocking the second surface side of the anode by the radial spacer.

[0132] [5] According to one form, there are also a plurality of second anode pressing parts, which clamp and fix the circumferential spacer and the back plate together with the first anode pressing part, and the second anode pressing parts are arranged corresponding to the circumferential spacer.

[0133] According to this form, the circumferential spacer and the back plate are clamped by the first anode pressing part and the second anode pressing part on the outside of the anode, thereby the anode and the radial spacer can be clamped by the anode pressing part and the back plate. In addition, by providing a plurality of second anode pressing parts corresponding to the circumferential spacer, the circumferential spacer can be effectively pressed by the second anode pressing parts.

[0134] [6] According to one embodiment, a plurality of pin-shaped spacers are further provided, and the plurality of pin-shaped spacers are provided to penetrate the rear plate and abut against the anode.

[0135] According to this aspect, pin-shaped spacers are used, so the installation area of ​​each spacer is small, and the installation position and / or number can be selected with a high degree of freedom.

[0136] [7] According to one form, the pin-shaped spacer is screwed into the threaded hole of the back plate and the tip thereof abuts against the anode.

[0137] According to this aspect, since the pin-shaped spacer is a threaded spacer, the interval between the anode and the rear plate can be easily adjusted according to the degree of screwing to the rear plate.

[0138] [8] According to one form, it comprises: a plating tank for holding a plating solution; an anode, which is arranged in the above-mentioned plating tank and has a plurality of through holes; a substrate holder, which holds the substrate in a manner facing the above-mentioned anode; a diaphragm, which is arranged in close contact with the first surface of the above-mentioned anode on the side of the above-mentioned substrate; and a bubble buffer ring, which is a bubble buffer ring provided in a manner to surround the above-mentioned anode and has an end face, the above-mentioned end face is arranged at a position of a specified height in the direction of the second surface on the opposite side of the above-mentioned first surface from the above-mentioned anode, and the amount of bubbles generated from the above-mentioned anode and accumulated on the above-mentioned second surface is adjusted by the above-mentioned end face.

[0139] According to this form, as described in [1] above, it is possible to suppress the accumulation of bubbles in the ion conduction path between the anode and the substrate, and to ensure the ion conduction path between the anode and the substrate so as to stably perform the plating of the substrate, thereby improving the uniformity of the plating film thickness distribution.

[0140] In addition, with regard to the bubbles accumulated on the second surface of the anode, the bubbles can always be accumulated from the second surface of the anode to the height of the end surface of the bubble buffer ring, and the bubbles always exist on the entire second surface of the anode, so that the change in the bubble accumulation amount accompanying the discharge of the bubbles on the second surface of the anode can be suppressed. The pressure change of the plating solution near the second surface of the anode can be suppressed, so the change in the electrode potential in the anode can be suppressed.

[0141] [9] According to one form, there is further provided an anode pressing portion, the anode pressing portion pressing the outer peripheral portion of the first surface of the anode, and the bubble buffer ring forms a predetermined gap between itself and the anode pressing portion at a position outside the anode.

[0142] According to this aspect, the plating solution can be allowed to infiltrate toward the anode side from the gap between the anode pressing portion and the bubble buffer ring.

[0143]

[10] According to one form, the bubble buffer ring comprises a plurality of first parts having a first thickness and a plurality of second parts thicker than the first thickness, the first parts and the second parts are alternately arranged in a circumferential direction of the buffer ring, and when the second parts are in contact with the anode pressing portion, the end face of the first part on the side away from the substrate forms the end face for adjusting the amount of the bubbles, and the end face of the first part on the side close to the substrate forms the specified gap between itself and the anode pressing portion.

[0144] According to this aspect, a bubble buffer ring having an end surface for adjusting the amount of bubbles and an end surface for forming a gap for intrusion of the plating solution can be realized with a simple structure.

[0145]

[11] According to one embodiment, a second pressing member is further provided, and the second pressing member, together with the anode pressing member, sandwiches and fixes the second portion of the bubble buffer ring.

[0146] According to this form, the second portion (thick wall portion) of the bubble buffer ring is clamped and fixed by the anode pressing portion and the second pressing portion member, thereby forming an end face for adjusting the amount of bubbles through the first portion of the bubble buffer ring and an end face for forming a gap for plating solution to enter.

[0147]

[12] According to one form, the plating device is constructed in such a way that the pressure of the plating solution in the cathode chamber closer to the substrate side than the diaphragm is greater than the pressure of the plating solution in the anode chamber closer to the anode side than the diaphragm, and the diaphragm is pressed against the surface of the anode closer to the substrate by the pressure of the plating solution in the cathode chamber.

[0148] According to this aspect, the separator is pressed against the anode by the pressure difference between the cathode chamber and the anode chamber, and the adhesion can be improved over the entire surface of the separator.

[0149]

[13] According to one form, an outlet that is connected to the anode chamber and is used to discharge bubbles from the anode chamber to the outside of the plating tank is provided in the plating tank.

[0150] According to this aspect, bubbles generated by the anode can be naturally exhausted through the exhaust port.

[0151]

[14] According to one form, the height of the side wall of the plating tank is set so that the overflow surface of the plating solution in the cathode chamber is higher than the overflow surface of the plating solution in the exhaust port.

[0152] According to this aspect, by setting the height of the side wall of the plating tank so that the overflow surface of the cathode chamber is higher than the overflow surface of the anode chamber, a pressure difference between the cathode chamber and the anode chamber can be formed with a simple structure.

[0153]

[15] According to one embodiment, the diaphragm is configured to be pressed against a surface of the anode on the substrate side by a pressing plate having a plurality of through holes.

[0154] According to this aspect, the ion conduction path can be ensured by the plurality of holes in the pressing plate, and the entire separator can be pressed against the anode to improve the adhesion.

[0155]

[16] According to one form, a seal for sealing between the pressure plate and the diaphragm is provided on the outer periphery of the diaphragm.

[0156] According to this aspect, it is possible to reliably prevent the anode chamber and the cathode chamber from communicating with each other at a portion other than the separator.

[0157]

[17] According to one embodiment, the diaphragm is bonded to a surface of the anode that is close to the substrate.

[0158] According to this aspect, the separator can be bonded to the anode to ensure close contact therewith.

[0159]

[18] According to one embodiment, the separator is bonded to the surface of the anode on the substrate side via an ion-permeable bonding layer.

[0160] According to this aspect, the separator can be bonded to the anode to ensure close contact therewith, and an ion conduction path from the anode to the substrate can be ensured via the bonding layer having ion permeability.

[0161]

[19] According to one form, a pressure ring for pressing the outer peripheral portion of the diaphragm and a seal for sealing between the pressure ring and the diaphragm are also provided.

[0162] According to this aspect, it is possible to reliably prevent the anode chamber and the cathode chamber from communicating with each other at a portion other than the separator.

[0163]

[20] According to one embodiment, the anode is an insoluble anode. According to this embodiment, it is possible to suppress the situation in which bubbles of gas generated by the insoluble anode during plating have a negative impact on the uniformity of the plating film thickness distribution. By using the insoluble anode, it is possible to improve the maintainability of the plating device and reduce the operating cost.

[0164]

[21] According to one form, the substrate holder holds the substrate with the plated surface of the substrate facing downward, and the anode is located below the substrate and faces the substrate. According to this form, in a so-called face-down plating device in which the anode faces upward relative to the substrate, it is possible to suppress the negative impact of gas bubbles generated by the anode during plating on the uniformity of the plated film thickness distribution.

[0165]

[22] According to one aspect, there is provided a plating method for plating a substrate, comprising preparing a plating device according to any one of [1] to

[21] above, and performing plating using the plating device.

[0166] The embodiments of the present invention have been described above, but the embodiments of the invention described above 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 at least a part of the above-mentioned problems that can be solved or at least a part of the effects that can be achieved, any combination of the embodiments and variations can be performed, and any combination or omission of the various structural elements described in the claims and the specification can be performed.

[0167] All disclosures of U.S. Patent Application No. 2020-0017989 (Patent Document 1) including the specification, claims, drawings, and abstract are incorporated herein by reference in their entirety.

[0168] Description of Reference Numerals

[0169] 10... plating tank; 10a... overflow dam; 10c... overflow dam; 11... exhaust port; 20... overflow trough; 31... substrate holder; 41... anode; 41A... through hole; 42... anode holder; 42A... notch; 42B... upper anode pressing portion; 42C... lower anode pressing portion; 42D... anode pressing portion; 42E... pressing portion member; 43... anode shield; 51... resistor; 61... air bubble; 71... diaphragm; 72... pressing plate; 72A... through hole; 74... fastening member ; 75...seal; 80...circulation path; 81...pump; 130...spacer; 131...circumferential spacer; 132...radial spacer; 140...gas regulating plate (back plate); 141...through hole; 150...ring for bubble buffer; 151...small diameter portion; 151A...lower end face; 151B...upper end face; 152...large diameter portion; 152A...lower end face; 152B...upper end face; 400...plating module; Ca...anode chamber; Cc...cathode chamber; Sa, Sc...overflow surface.

Claims

1. A plating device, characterized in that: have: a plating tank for holding a plating solution; an anode, which is disposed in the plating tank and has a plurality of through holes; a substrate holder for holding the substrate so as to face the anode; a diaphragm arranged in close contact with the first surface of the anode on the substrate side; as well as a back plate which faces the second surface of the anode on the opposite side to the first surface and is arranged to be separated from the second surface by a predetermined interval in a manner having the same shape as the anode and covering the entire back surface of the anode, and adjusts the amount of bubbles generated from the anode and accumulated on the second surface, The substrate holder holds the substrate with the plated surface of the substrate facing downward, and the anode faces the substrate below the substrate.

2. The plating device according to claim 1, characterized in that The back plate has a larger diameter than the anode.

3. A plating device, characterized in that: have: a plating tank for holding a plating solution; an anode, which is disposed in the plating tank and has a plurality of through holes; a substrate holder for holding the substrate so as to face the anode; a diaphragm arranged in close contact with the first surface of the anode on the substrate side; as well as a back plate which is disposed facing a second surface of the anode opposite to the first surface and separated from the second surface by a predetermined interval, and which regulates the amount of bubbles generated from the anode and accumulated on the second surface, A radial spacer is further provided. The radial spacer is provided between the back plate and the anode and a plurality of radial spacers are arranged along the circumferential direction of the anode. Each radial spacer extends in the radial direction between the center and the outer periphery of the back plate.

4. The plating device according to claim 3, characterized in that: Also available: a first anode pressing portion that presses an outer peripheral portion of the first surface of the anode; and A plurality of circumferential spacers are provided between the back plate and the first anode pressing portion and are arranged along the circumferential direction of the anode.

5. The plating device according to claim 4, characterized in that: The radial spacer is provided every other circumferential spacer among the plurality of circumferential spacers.

6. The plating device according to claim 5, characterized in that: The invention further comprises a plurality of second anode pressing portions, the plurality of second anode pressing portions sandwiching and fixing the circumferential spacer and the back plate together with the first anode pressing portion, and the second anode pressing portions are provided corresponding to the circumferential spacer.

7. A plating device, characterized in that: have: a plating tank for holding a plating solution; an anode, which is disposed in the plating tank and has a plurality of through holes; a substrate holder for holding the substrate so as to face the anode; a diaphragm arranged in close contact with the first surface of the anode on the substrate side; as well as a back plate which is disposed facing a second surface of the anode opposite to the first surface and separated from the second surface by a predetermined interval, and which regulates the amount of bubbles generated from the anode and accumulated on the second surface, A plurality of pin-shaped spacers are further provided, and the plurality of pin-shaped spacers are provided to penetrate the rear plate and to abut against the anode.

8. The plating device according to claim 7, characterized in that: The pin-shaped spacer is screwed into the threaded hole of the back plate and the distal end thereof abuts against the anode.

9. A plating device, characterized in that: have: a plating tank for holding a plating solution; an anode, which is disposed in the plating tank and has a plurality of through holes; a substrate holder for holding the substrate so as to face the anode; a diaphragm arranged in close contact with the first surface of the anode on the substrate side; as well as A bubble buffer ring is a bubble buffer ring arranged in a manner to surround the anode and has an end face, wherein the end face is arranged at a position of a specified height in the direction of a second face on the opposite side of the anode to the first face, and the amount of bubbles generated from the anode and accumulated on the second face is regulated by the end face.

10. The plating device according to claim 9, characterized in that: further comprising an anode pressing portion for pressing an outer peripheral portion of the first surface of the anode, The bubble buffer ring forms a predetermined gap between itself and the anode pressing portion at a position outside the anode.

11. The plating device according to claim 10, characterized in that: The bubble buffer ring includes a plurality of first portions having a first thickness and a plurality of second portions thicker than the first thickness, wherein the first portions and the second portions are alternately arranged in a circumferential direction of the buffer ring. When the second part abuts against the anode pressing portion, the end face of the first part on the side away from the substrate forms the end face for adjusting the amount of the bubbles, and the end face of the first part close to the substrate forms the specified gap between itself and the anode pressing portion.

12. The plating device according to claim 11, characterized in that: A second pressing member is further provided, and the second pressing member sandwiches and fixes the second portion of the bubble buffer ring together with the anode pressing portion.

13. The plating device according to any one of claims 1 to 12, characterized in that: The plating device is constructed in such a way that the pressure of the plating solution in the cathode chamber closer to the substrate side than the diaphragm is greater than the pressure of the plating solution in the anode chamber closer to the anode side than the diaphragm, and the diaphragm is pressed against the surface of the anode closer to the substrate by the pressure of the plating solution in the cathode chamber.

14. The plating device according to any one of claims 1 to 12, characterized in that: The plating tank has an outlet that communicates with an anode chamber on the anode side of the diaphragm and is used to discharge bubbles from the anode chamber to the outside of the plating tank.

15. The plating device according to claim 14, characterized in that: The height of the side wall of the plating tank is set so that an overflow surface of the plating solution in the cathode chamber on the substrate side relative to the diaphragm is higher than an overflow surface of the plating solution in the discharge port.

16. The plating device according to any one of claims 1 to 12, characterized in that: The separator is arranged so as to be pressed against a surface of the anode on the substrate side by a pressing plate having a plurality of through holes.

17. The plating device according to claim 16, characterized in that: A seal for sealing between the pressure plate and the diaphragm is provided on the outer periphery of the diaphragm.

18. The plating device according to any one of claims 1 to 12, characterized in that: The separator is bonded to a surface of the anode that is close to the substrate.

19. The plating device according to claim 18, characterized in that: The separator is bonded to a surface of the anode on the substrate side via an ion-permeable bonding layer.

20. The plating device according to claim 18, characterized in that A pressure ring for pressing the outer periphery of the diaphragm and a seal for sealing between the pressure ring and the diaphragm are also provided.

21. The plating device according to any one of claims 1 to 12, characterized in that: The anode is an insoluble anode.

22. The plating device according to any one of claims 3 to 8, characterized in that: The rear plate has the same shape as the anode and is configured to cover the entire rear surface of the anode.

23. The plating device according to claim 22, characterized in that: The back plate has a larger diameter than the anode.

24. A plating method, which is a method for plating a substrate, characterized in that: The plating apparatus according to any one of claims 1 to 23 is prepared, and plating is performed using the plating apparatus.

Images