Air bubble removal method for plating device

Abstract

Provided is a technique with which it is possible to suppress deterioration in plating quality of a substrate caused by air bubbles.　This air bubble removal method for a plating device includes: performing a first process for making the pressure of an anode chamber higher than the pressure of a cathode chamber, thereby causing a diaphragm to protrude upward, and collecting air bubbles onto the lower surface of the portion of the diaphragm protruding upward; performing a second process for making the pressure of the cathode chamber higher than the pressure of the anode chamber, thereby causing the diaphragm to protrude downward, and moving the air bubbles to the outer peripheral edge of the diaphragm; and performing a third process for causing the air bubbles moved to the outer peripheral edge of the diaphragm to be suctioned into an anolyte discharge port disposed in the anode chamber, and discharged from the anode chamber.

Description

Bubble removal method for plating apparatus

[0001] The present invention relates to a method for removing bubbles from a plating apparatus.

[0002] Conventionally, as a plating apparatus, a plating apparatus in which the inside of a plating tank is partitioned into an anode chamber and a cathode chamber by a diaphragm is known (for example, see Patent Document 1). In such a plating apparatus, an anode is disposed in the anode chamber, and a substrate as a cathode is disposed in the cathode chamber. Further, an anode solution is stored in the anode chamber, and a cathode solution is stored in the cathode chamber.

[0003] Japanese Patent Application Laid-Open No. 2022-59250

[0004] In the plating apparatus as described above, due to some cause, bubbles may occur in the anode solution in the anode chamber. When bubbles occur in the anode solution in the anode chamber and these bubbles stay on the lower surface of the diaphragm, the plating quality of the substrate may deteriorate due to these bubbles.

[0005] The present invention has been made in view of the above, and one of its objects is to provide a technique capable of suppressing deterioration of the plating quality of a substrate due to bubbles.

[0006] (Aspect 1) To achieve the above objective, one aspect of the present invention is a method for removing bubbles from a plating apparatus, the plating apparatus comprising a plating tank, a diaphragm provided inside the plating tank, the inside of the plating tank being divided by the diaphragm into an anode chamber below the diaphragm and a cathode chamber above the diaphragm, an anode being placed in the anode chamber, and a substrate as a cathode being placed in the cathode chamber facing the anode, the bubble removal method comprising: performing a first process of increasing the pressure in the anode chamber to a higher pressure in the cathode chamber to cause the diaphragm to protrude upward and collect bubbles on the lower surface of the portion of the diaphragm that protrudes upward; performing a second process of increasing the pressure in the cathode chamber to a higher pressure in the anode chamber to cause the diaphragm to protrude downward and move the bubbles to the outer edge of the diaphragm; and performing a third process of drawing the bubbles that have moved to the outer edge of the diaphragm into an anode liquid outlet located in the anode chamber and discharging them from the anode chamber.

[0007] According to this embodiment, it is possible to suppress deterioration of the plating quality of the substrate due to air bubbles.

[0008] (Aspect 2) In the first process according to the above-described aspect 1, making the pressure in the anode chamber higher than the pressure in the cathode chamber may include making the flow rate of the anode liquid supplied to the anode chamber from an anode liquid supply port located in the anode chamber greater than the flow rate of the cathode liquid supplied to the cathode chamber from a cathode liquid supply port located in the cathode chamber.

[0009] (Aspect 3) In the second process according to the above aspect 2, making the pressure in the cathode chamber higher than the pressure in the anode chamber may include making the flow rate of the cathode liquid supplied from the cathode liquid supply port to the cathode chamber greater than the flow rate of the anode liquid supplied from the anode liquid supply port to the anode chamber.

[0010] (Aspect 4) In the above-described aspect 2, the pressure in the anode chamber may be made higher than the pressure in the cathode chamber in the first process by supplying anode liquid to the anode chamber from the anode liquid supply port while stopping the flow of cathode liquid supplied to the cathode chamber from the cathode liquid supply port.

[0011] (Aspect 5) In the above-described aspect 3, the pressure in the cathode chamber may be made higher than the pressure in the anode chamber in the second process by supplying cathode liquid to the cathode chamber from the cathode liquid supply port while stopping the flow of anode liquid supplied to the anode chamber from the anode liquid supply port.

[0012] (Aspect 6) In aspect 5 described above, the diaphragm may be arranged to be inclined with respect to the horizontal direction, and the anode liquid outlet may be located directly below the uppermost portion of the inclined outer edge of the diaphragm.

[0013] (Aspect 7) In the above-described aspect 6, the plating apparatus may be provided with a holding member for holding the outer peripheral edge of the diaphragm, and the anode liquid outlet may be positioned directly below the uppermost portion so as to be in contact with the holding member.

[0014] (Aspect 8) In aspect 7 described above, a plurality of anode liquid supply ports may be provided along the outer edge of the diaphragm.

[0015] (Aspect 9) In aspect 8 described above, at least one of the plurality of anode liquid supply ports may be arranged to be in contact with the holding member.

[0016] This is a perspective view showing the overall configuration of the plating apparatus according to the embodiment. This is a plan view showing the overall configuration of the plating apparatus according to the embodiment. This is a schematic diagram showing the configuration of the plating module according to the embodiment. This is a schematic cross-sectional view showing an enlarged view of the area near the diaphragm of the plating bath according to the embodiment. This is an example of a flowchart for explaining the bubble removal process according to the embodiment. Figure 6(A) is a schematic diagram showing the state of the diaphragm during the execution of the first process. Figure 6(B) is a schematic diagram showing the state of the diaphragm during the execution of the second process. This is a schematic cross-sectional view for explaining a modified example of the diaphragm of the embodiment. This is a schematic bottom view showing the peripheral configuration of the diaphragm as viewed from below in the configuration illustrated in Figure 7.

[0017] Embodiments of the present invention will be described below with reference to the drawings. Note that the drawings are schematic in order to facilitate understanding of the features of the embodiments, and the dimensional ratios of each component may not be the same as those of the actual components. Also, some drawings show X-Y-Z Cartesian coordinates for reference. In these Cartesian coordinates, the Z direction corresponds to upward, and the -Z direction corresponds to downward (the direction in which gravity acts).

[0018] Figure 1 is a perspective view showing the overall configuration of the plating apparatus 1000 of this embodiment. Figure 2 is a plan view (top view) showing the overall configuration of the plating apparatus 1000 of this embodiment. As shown in Figures 1 and 2, the plating apparatus 1000 includes a load port 100, a transport robot 110, an aligner 120, a pre-wet module 200, a pre-soak module 300, a plating module 400, a cleaning module 500, a spin rinse dryer 600, a transport device 700, and a control module 800.

[0019] The load port 100 is a module for loading substrates contained in cassettes such as FOUPs (not shown) into the plating apparatus 1000, and for unloading substrates from the plating apparatus 1000 into cassettes. In this embodiment, four load ports 100 are arranged horizontally, but the number and arrangement of load ports 100 are arbitrary. The transport robot 110 is a robot for transporting substrates and is configured to transfer substrates between the load port 100, the aligner 120, the pre-wet module 200, and the spin rinse dryer 600. When transferring substrates between the transport robot 110 and the transport device 700, the substrates can be transferred via a temporary stand (not shown).

[0020] The aligner 120 is a module for aligning the positions of orientation flats, notches, etc., on the substrate in a predetermined direction. In this embodiment, two aligners 120 are arranged side by side horizontally, but the number and arrangement of the aligners 120 are arbitrary. The pre-wet module 200 replaces the air inside the patterns formed on the substrate surface with a treatment solution by wetting the surface of the substrate to be plated with a treatment solution such as pure water or degassed water before the plating process. The pre-wet module 200 is configured to perform a pre-wetting process that makes it easier to supply the plating solution inside the patterns by replacing the treatment solution inside the patterns with the plating solution during plating. In this embodiment, two pre-wet modules 200 are arranged side by side vertically, but the number and arrangement of the pre-wet modules 200 are arbitrary.

[0021] The pre-soak module 300 is configured to perform a pre-soak treatment, which involves etching away an oxide film with high electrical resistance present on the surface of a seed layer formed on the surface of a substrate to be plated before plating, using a treatment solution such as sulfuric acid or hydrochloric acid, thereby cleaning or activating the surface of the substrate. In this embodiment, two pre-soak modules 300 are arranged side by side in the vertical direction, but the number and arrangement of the pre-soak modules 300 are arbitrary. The plating module 400 performs the plating treatment on the substrate. In this embodiment, there are two sets of 12 plating modules 400, arranged in a vertical direction of three modules and horizontal direction of four modules, for a total of 24 plating modules 400, but the number and arrangement of the plating modules 400 are arbitrary.

[0022] The cleaning module 500 is configured to clean the substrate to remove any remaining plating solution after the plating process. In this embodiment, two cleaning modules 500 are arranged side by side in the vertical direction, but the number and arrangement of the cleaning modules 500 are arbitrary. The spin rinse dryer 600 is a module for drying the substrate after the cleaning process by rotating it at high speed. In this embodiment, two spin rinse dryers 600 are arranged side by side in the vertical direction, but the number and arrangement of the spin rinse dryers 600 are arbitrary. The transport device 700 is a device for transporting substrates between multiple modules in the plating apparatus 1000. The control module 800 is configured to control multiple modules of the plating apparatus 1000 and can consist of, for example, a general-purpose computer or a dedicated computer with an input / output interface with an operator.

[0023] An example of a series of plating processes performed by the plating apparatus 1000 will be described. First, substrates contained in cassettes are loaded into the load port 100. Next, the transport robot 110 removes the substrates from the cassettes in the load port 100 and transports them to the aligner 120. The aligner 120 aligns the orientation flats, notches, and other positions of the substrates to a predetermined direction. The transport robot 110 then transfers the substrates, whose orientation has been aligned by the aligner 120, to the pre-wet module 200.

[0024] The pre-wetting module 200 performs a pre-wetting treatment on the substrate. The transport device 700 transports the pre-wetting substrate to the pre-soak module 300. The pre-soak module 300 performs a pre-soak treatment on the substrate. The transport device 700 transports the pre-soaked substrate to the plating module 400. The plating module 400 performs a plating treatment on the substrate.

[0025] The transport device 700 transports the plated substrate to the cleaning module 500. The cleaning module 500 cleans the substrate. The transport device 700 then transports the cleaned substrate to the spin rinse dryer 600. The spin rinse dryer 600 dries the substrate. The transport robot 110 receives the substrate from the spin rinse dryer 600 and transports the dried substrate to the cassette in the load port 100. Finally, the cassette containing the substrate is discharged from the load port 100.

[0026] The configuration of the plating apparatus 1000 described in Figures 1 and 2 is merely an example, and the configuration of the plating apparatus 1000 is not limited to the configurations shown in Figures 1 and 2.

[0027] Next, the plating module 400 will be described. Since the multiple plating modules 400 in the plating apparatus 1000 according to this embodiment have similar configurations, only one plating module 400 will be described.

[0028] Figure 3 is a schematic diagram showing the configuration of one plating module 400 in the plating apparatus 1000 according to this embodiment. The plating apparatus 1000 according to this embodiment is a so-called cup-type plating apparatus. Specifically, as illustrated in Figure 3, the plating module 400 according to this embodiment includes a plating tank 10, a substrate holder 30, a rotating mechanism 40, and a lifting mechanism 45.

[0029] The plating tank 10 according to this embodiment is a bottomed container with an opening at the top. Specifically, the plating tank 10 has a bottom wall 11 and an outer peripheral wall 12 that extends upward from the outer peripheral edge of the bottom wall 11, with the upper part of the outer peripheral wall 12 being open. The shape of the outer peripheral wall 12 of the plating tank 10 is not particularly limited, but the outer peripheral wall 12 according to this embodiment has a cylindrical shape as an example.

[0030] A diaphragm 61 is provided inside the plating tank 10. Figure 4 is a schematic cross-sectional view showing an enlarged view of the area near the diaphragm 61 of the plating tank 10. Referring to Figures 3 and 4, the outer periphery of the diaphragm 61 (specifically, the outer edge of the circular diaphragm 61) is connected to the outer wall 12 of the plating tank 10 via a ring-shaped retaining member 62. That is, the retaining member 62 is a member for holding the outer edge of the diaphragm 61. The inside of the plating tank 10 is divided into two sections vertically by the diaphragm 61. The area partitioned below the diaphragm 61 is called the anode chamber 13. The area above the diaphragm 61 is called the cathode chamber 14.

[0031] Referring to Figure 3, an anode 60 is placed in the anode chamber 13. In the cathode chamber 14, a substrate Wf, which serves as a cathode, is placed facing the anode 60. The anode chamber 13 stores anode solution Ps1 (plating solution). The cathode chamber 14 stores cathode solution Ps2 (plating solution). An overflow tank may be provided outside the outer peripheral wall 12 of the plating tank 10 to contain the leaked cathode solution Ps2 if it leaks from the cathode chamber 14 beyond the upper end of the outer peripheral wall 12 to the outside of the plating tank 10.

[0032] In this embodiment, the diaphragm 61 is positioned horizontally when the pressure in the anode chamber 13 and the pressure in the cathode chamber 14 are equal (see Figure 4). However, the configuration is not limited to this. As another example, as illustrated in Figure 7, the diaphragm 61 may be positioned inclined with respect to the horizontal when the pressure in the anode chamber 13 and the pressure in the cathode chamber 14 are equal.

[0033] Referring to Figures 3 and 4, the diaphragm 61 is composed of a membrane that allows the passage of metal ions while suppressing the passage of additives contained in the plating solution. That is, in this embodiment, the cathode solution Ps2 in the cathode chamber 14 contains additives, but the anode solution Ps1 in the anode chamber 13 does not contain additives. However, the configuration is not limited to this, and for example, the anode solution Ps1 may also contain additives. However, even in this case, the concentration of additives in the anode solution Ps1 is lower than the concentration of additives in the cathode solution Ps2.

[0034] The specific type of diaphragm 61 is not particularly limited, and any known diaphragm can be used. Specific examples of this diaphragm 61 include, for example, an electrolytic diaphragm, and specific examples of this electrolytic diaphragm include, for example, an electrolytic diaphragm for plating manufactured by Yuasa Membrane Systems Co., Ltd., or an ion exchange membrane, etc.

[0035] As in this embodiment, by providing a diaphragm 61 inside the plating tank 10, it is possible to suppress the phenomenon in which components that adversely affect the plating process of the substrate Wf are generated by the decomposition or reaction of additive components in the plating solution during the reaction on the anode side (i.e., "adverse effects caused by additive components").

[0036] The specific type of anode 60 is not particularly limited and may be an insoluble anode or a soluble anode. In this embodiment, an insoluble anode is used as an example of anode 60. The specific type of this insoluble anode is not particularly limited and may be platinum, iridium oxide, or the like.

[0037] Referring to Figure 3, the substrate holder 30 holds the substrate Wf, which serves as the cathode, so that the plated surface (bottom surface) of the substrate Wf faces the anode 60. The substrate holder 30 is connected to a rotating mechanism 40. The rotating mechanism 40 is a mechanism for rotating the substrate holder 30. The rotating mechanism 40 is connected to a lifting mechanism 45. The lifting mechanism 45 is supported by a support column 46 that extends in the vertical direction. The lifting mechanism 45 is a mechanism for raising and lowering the substrate holder 30 and the rotating mechanism 40. The substrate Wf and the anode 60 are electrically connected to a power supply device (not shown). The power supply device is a device for supplying current between the substrate Wf and the anode 60 when the plating process is performed.

[0038] When plating is applied to the substrate Wf, the rotating mechanism 40 rotates the substrate holder 30, and the lifting mechanism 45 moves the substrate holder 30 downward, immersing the substrate Wf in the plating solution (specifically the cathode solution Ps2) in the plating bath 10. Next, an electric current is passed between the anode 60 and the substrate Wf by the energizing device. As a result, a plating film is formed on the plated surface (bottom surface) of the substrate Wf.

[0039] The control module 800 according to this embodiment includes a microcomputer having a processor 801 and a storage device 802 as a non-temporary storage medium. The control module 800 controls the operation of the plating module 400 by having the processor 801 operate based on program commands stored in the storage device 802.

[0040] Referring to Figure 3, the plating module 400 according to this embodiment includes an anode solution circulation device 70 for circulating the anode solution Ps1 and a cathode solution circulation device 80 for circulating the cathode solution Ps2.

[0041] Referring to FIGS. 3 and 4, the anode liquid circulation device 70 according to the present embodiment includes an anode liquid supply port 71, an anode liquid discharge port 72, an anode liquid circulation line 73, and an anode liquid pump 74. Further, the anode liquid circulation device 70 may include a flow rate adjustment valve 78a and a flow rate adjustment valve 78b. Further, the anode liquid circulation device 70 may include a reservoir tank 75 for the anode liquid.

[0042] Referring to FIG. 4, the anode liquid supply port 71 is disposed in the anode chamber 13 and configured to supply the anode liquid Ps1 to the anode chamber 13. Specifically, the anode liquid supply port 71 according to the present embodiment is, for example, disposed on the outer peripheral wall 12 of the anode chamber 13. More specifically, the anode liquid supply port 71 according to the present embodiment is, for example, disposed at a location below the outer peripheral edge of the diaphragm 61 in the anode chamber 13 such that at least a part of the anode liquid discharge port 72 contacts the holding member 62.

[0043] The anode liquid discharge port 72 is disposed in the anode chamber 13 and configured to discharge the anode liquid Ps1 in the anode chamber 13. Specifically, the anode liquid discharge port 72 according to the present embodiment is disposed on the outer peripheral wall 12 of the anode chamber 13. Further, the anode liquid discharge port 72 according to the present embodiment is disposed at a location where it is possible to suck in the bubbles Bu that have moved to the outer peripheral edge of the diaphragm 61 in the anode chamber 13 (see FIG. 6(B) described later).

[0044] If it is such a location, the specific arrangement location of the anode liquid discharge port 72 is not particularly limited, but the anode liquid discharge port 72 according to the present embodiment is, for example, disposed at a location below the outer peripheral edge of the diaphragm 61 in the anode chamber 13. Specifically, the anode liquid discharge port 72 according to the present embodiment is disposed at a location directly below the holding member 62. More specifically, the anode liquid discharge port 72 according to the present embodiment is disposed such that at least a part of the anode liquid discharge port 72 contacts the holding member 62.

[0045] Incidentally, as illustrated in FIG. 4, the anode liquid supply port 71 may be provided so as to face the anode liquid discharge port 72. According to this configuration, in the anode chamber 13, a "shearing flow Sf of the anode liquid" along the lower surface 61b of the diaphragm 61 can be easily formed on the lower surface 61b. In this case, the bubbles Bu described later can be easily placed on the shearing flow Sf and discharged from the anode liquid discharge port 72.

[0046] Further, as described above with reference to FIG. 7, when the diaphragm 61 is disposed in an inclined state with respect to the horizontal direction, the anode liquid discharge port 72 may be disposed directly below the portion located at the uppermost part among the outer peripheral edges of the inclined diaphragm 61 (see FIG. 7). According to this configuration, the bubbles Bu described later can be effectively sucked into the anode liquid discharge port 72. That is, the bubbles Bu can be efficiently removed.

[0047] Further, in this case, as illustrated in FIG. 7, the anode liquid discharge port 72 may be disposed so as to contact the holding member 62 directly below the portion located at the uppermost part among the outer peripheral edges of the inclined diaphragm 61. According to this configuration, the bubbles Bu can be removed more efficiently.

[0048] FIG. 8 is a schematic bottom view of the peripheral configuration of the diaphragm 61 as viewed from the lower side in the configuration illustrated in FIG. 7. As illustrated in FIG. 8, a plurality of anode liquid supply ports 71 may be provided along the outer peripheral edge of the diaphragm 61. In the configuration illustrated in FIG. 8, as an example, three anode liquid supply ports 71 are provided. However, the number of the plurality of anode liquid supply ports 71 is not limited to three, and may be two or four or more.

[0049] According to this configuration, the flow of the anode liquid Ps1 along the surface of the lower surface 61b of the diaphragm 61 can be effectively formed. Thereby, the bubbles Bu can be effectively collected by utilizing the flow of the anode liquid Ps1 and discharged from the anode liquid discharge port 72.

[0050] In this case, at least one of the multiple anode liquid supply ports 71 may be arranged to be in contact with the holding member 62. This configuration allows for a more efficient flow of anode liquid Ps1 along the lower surface 61b of the diaphragm 61. In Figure 8, as an example, all of the multiple anode liquid supply ports 71 are arranged to be in contact with the lower surface of the holding member 62.

[0051] Referring to Figure 3, the anode fluid circulation line 73 is located outside the anode chamber 13 and is configured to connect the anode fluid outlet 72 and the anode fluid supply port 71.

[0052] The anode liquid pump 74 is configured to return the anode liquid Ps1 discharged from the anode liquid outlet 72 back to the anode liquid supply port 71. Specifically, the anode liquid pump 74 according to this embodiment is located in the anode liquid circulation line 73 and is controlled by the control module 800 to pump the anode liquid Ps1.

[0053] The flow control valve 78a communicates with the anode liquid supply port 71 and adjusts the flow rate of the anode liquid Ps1 supplied to the anode liquid supply port 71. The flow control valve 78b communicates with the anode liquid outlet 72 and adjusts the flow rate of the anode liquid Ps1 discharged from the anode liquid outlet 72. The operation of the flow control valves 78a and 78b is controlled by the control module 800.

[0054] The reservoir tank 75 is located in the anode fluid circulation line 73. The reservoir tank 75 is a tank for temporarily storing the anode fluid Ps1 discharged from the anode fluid outlet 72.

[0055] Referring to Figures 3 and 4, the cathode fluid circulation device 80 according to this embodiment includes a cathode fluid supply port 81, a cathode fluid outlet port 82, a cathode fluid circulation line 83, and a cathode fluid pump 84. The cathode fluid circulation device 80 may also include a flow control valve 88a and a flow control valve 88b. The cathode fluid circulation device 80 may also include a reservoir tank 85 for the cathode fluid.

[0056] Referring to Figure 4, the cathode liquid supply port 81 is located in the cathode chamber 14 and is configured to supply the cathode liquid Ps2 to the cathode chamber 14. Specifically, the cathode liquid supply port 81 according to this embodiment is located on the outer peripheral wall 12 of the cathode chamber 14. As an example, the cathode liquid supply port 81 according to this embodiment is provided at a location above the outer peripheral edge of the diaphragm 61 in the cathode chamber 14.

[0057] The cathode liquid outlet 82 is located in the cathode chamber 14 and is configured to discharge the cathode liquid Ps2 from the cathode chamber 14. Specifically, the cathode liquid outlet 82 in this embodiment is located on the outer peripheral wall 12 of the cathode chamber 14. For example, the cathode liquid outlet 82 in this embodiment is provided above the outer peripheral edge of the diaphragm 61 in the cathode chamber 14. Alternatively, the cathode liquid outlet 82 may be provided facing the cathode liquid supply port 81, for example.

[0058] However, the arrangement of the cathode liquid supply port 81 and cathode liquid outlet 82 described above is merely one example, and the cathode liquid supply port 81 and cathode liquid outlet 82 are not limited to these examples.

[0059] Referring to Figure 3, the cathode fluid circulation line 83 is located outside the cathode chamber 14 and is configured to connect the cathode fluid outlet 82 and the cathode fluid supply port 81.

[0060] The cathode fluid pump 84 is configured to return the cathode fluid Ps2 discharged from the cathode fluid outlet 82 back to the cathode fluid supply port 81. Specifically, the cathode fluid pump 84 according to this embodiment is located in the cathode fluid circulation line 83 and is controlled by the control module 800 to pump the cathode fluid Ps2.

[0061] The flow rate control valve 88a communicates with the cathode fluid supply port 81 and adjusts the flow rate of the cathode fluid Ps2 supplied to the cathode fluid supply port 81. The flow rate control valve 88b communicates with the cathode fluid outlet port 82 and adjusts the flow rate of the cathode fluid Ps2 discharged from the cathode fluid outlet port 82. The operation of the flow rate control valves 88a and 88b is controlled by the control module 800.

[0062] The reservoir tank 85 is located in the cathode fluid circulation line 83. The reservoir tank 85 is a tank for temporarily storing the cathode fluid Ps2 discharged from the cathode fluid outlet 82.

[0063] The number of anode solution supply ports 71 and anode solution outlet ports 72 is not limited to one each. The plating module 400 may have multiple anode solution supply ports 71 and multiple anode solution outlet ports 72. Similarly, the number of cathode solution supply ports 81 and cathode solution outlet ports 82 is not limited to one each. The plating module 400 may have multiple cathode solution supply ports 81 and multiple cathode solution outlet ports 82.

[0064] In addition, the plating apparatus 1000 may, as an example, circulate the anode solution Ps1 and / or the cathode solution Ps2 during the plating process. That is, the substrate Wf may be plated while the anode solution Ps1 and / or the cathode solution Ps2 are circulating.

[0065] By the way, in a plating apparatus 1000 like the one in this embodiment, bubbles Bu may be generated in the anode solution Ps1 of the anode chamber 13 for some reason (see Figure 4). Specifically, when an insoluble anode is used as the anode 60 as in this embodiment, during the plating process (when current is applied), oxygen (O) is generated in the anode solution Ps1 of the anode chamber 13 based on the following reaction equation. ２ This occurs. In this case, the generated oxygen becomes a bubble called Bu.

[0066] 2H ２ O→O ２ +4H + +4e -

[0067] Furthermore, if a dissolved anode is used as the anode 60, the above reaction equation will not occur. However, for example, when the anode solution Ps1 is first introduced into the anode chamber 13, there is a risk that air may flow into the anode chamber 13 along with the anode solution Ps1. Therefore, even when a dissolved anode is used as the anode 60, there is a risk that bubbles Bu may be generated in the anode solution Ps1 in the anode chamber 13.

[0068] As described above, if bubbles Bu occur in the anode chamber 13, and these bubbles Bu remain on the entire lower surface 61b of the diaphragm 61 (in other words, if bubbles Bu adhere to the entire lower surface 61b of the diaphragm 61), these bubbles Bu may interrupt the electric field, potentially degrading the plating quality of the substrate Wf. Therefore, in this embodiment, in order to suppress the accumulation of bubbles Bu on the lower surface 61b of the diaphragm 61 and to prevent the deterioration of the plating quality of the substrate Wf due to these bubbles Bu, a bubble removal treatment (bubble removal method) described below is performed.

[0069] Figure 5 is an example of a flowchart illustrating the bubble removal process according to this embodiment. Each step in the flowchart of Figure 5 may be executed by the processor 801 of the control module 800. The execution timing (predetermined timing) of the flowchart of Figure 5 is not particularly limited, but for example, the control module 800 may execute this flowchart at any time during the plating process on the substrate Wf, or at any time before or after the plating process.

[0070] First, the control module 800 performs a first process (step S10). Figure 6(A) is a schematic diagram showing the state of the diaphragm 61 during the execution of the first process. In this first process, the control module 800 controls the anode liquid circulation device 70 and the cathode liquid circulation device 80 to raise the pressure in the anode chamber 13 (specifically, the pressure of the anode liquid Ps1 in the anode chamber 13) higher than the pressure in the cathode chamber 14 (specifically, the pressure of the cathode liquid Ps2 in the cathode chamber 14), thereby causing the diaphragm 61 to protrude upward. This allows bubbles Bu to be collected on the lower surface 61b of the portion 61a that protrudes upward from the diaphragm 61.

[0071] Specifically, in this case, the central part of the diaphragm 61 protrudes upward, and bubbles Bu are collected on the lower surface 61b of this upwardly protruding portion 61a. More specifically, when step S10 is performed, multiple bubbles Bu that were present on the lower surface 61b of the diaphragm 61 before step S10 are collected on the lower surface 61b of the upwardly protruding portion 61a of the diaphragm 61, mainly using buoyancy, and can be made into larger bubbles Bu.

[0072] In step S10, for example, the control module 800 may control the anode fluid circulator 70 and the cathode fluid circulator 80 such that the flow rate of the anode fluid Ps1 supplied from the anode fluid supply port 71 is greater than the flow rate of the cathode fluid Ps2 supplied from the cathode fluid supply port 81, thereby raising the pressure in the anode chamber 13 higher than the pressure in the cathode chamber 14.

[0073] Furthermore, when the control module 800 makes the flow rate of the anode liquid Ps1 greater than the flow rate of the cathode liquid Ps2, it may set the output (rpm) of the anode liquid pump 74 higher than the output of the cathode liquid pump 84. Alternatively, the control module 800 may make the flow rate of the anode liquid Ps1 greater than the flow rate of the cathode liquid Ps2 by controlling the flow rate control valves 78a and 88a.

[0074] Alternatively, the control module 800 may circulate the anode fluid Ps1 while stopping the circulation of the cathode fluid Ps2, thereby raising the pressure in the anode chamber 13 higher than the pressure in the cathode chamber 14.

[0075] In other words, raising the pressure in the anode chamber 13 to be higher than the pressure in the cathode chamber 14 during the first process may be done by supplying anode liquid Ps1 to the anode chamber 13 from the anode liquid supply port 71 while stopping the flow of cathode liquid Ps2 supplied to the cathode chamber 14 from the cathode liquid supply port 81. With this configuration, the pressure in the anode chamber 13 can be raised to be higher than the pressure in the cathode chamber 14 in a simple manner.

[0076] Step S10 may be performed for a predetermined time ("first processing time"), for example. The specific value of this first processing time is not particularly limited, but for example, a time sufficient to collect bubbles Bu on the lower surface 61b of the protruding portion 61a of the diaphragm 61 may be determined by experimentation or other means and used. This first processing time may be stored in the storage device 802 in advance.

[0077] Referring to Figure 5, after step S10, the control module 800 executes the second process related to step S20. Figure 6(B) is a schematic diagram showing the state of the diaphragm 61 during the execution of the second process. In this second process, the control module 800 controls the anode liquid circulation device 70 and the cathode liquid circulation device 80 to raise the pressure in the cathode chamber 14 higher than the pressure in the anode chamber 13, thereby causing the diaphragm 61 to protrude downward. This allows the bubbles Bu collected in step S10 (bubbles Bu that have grown larger) to move to the outer edge 61c of the diaphragm 61.

[0078] In step S20, for example, the control module 800 may control the anode fluid circulator 70 and the cathode fluid circulator 80 such that the flow rate of cathode fluid Ps2 supplied from the cathode fluid supply port 81 is greater than the flow rate of anode fluid Ps1 supplied from the anode fluid supply port 71, thereby raising the pressure in the cathode chamber 14 higher than the pressure in the anode chamber 13.

[0079] Furthermore, when the control module 800 makes the flow rate of the cathode fluid Ps2 greater than the flow rate of the anode fluid Ps1, it may set the output (rpm) of the cathode fluid pump 84 higher than the output of the anode fluid pump 74. Alternatively, the control module 800 may make the flow rate of the cathode fluid Ps2 greater than the flow rate of the anode fluid Ps1 by controlling the flow rate control valves 78a and 88a.

[0080] Alternatively, the control module 800 may circulate the cathode fluid Ps2 while stopping the circulation of the anode fluid Ps1, thereby raising the pressure in the cathode chamber 14 higher than the pressure in the anode chamber 13.

[0081] In other words, in the second process, raising the pressure in the cathode chamber 14 to be higher than the pressure in the anode chamber 13 may be done by supplying cathode liquid Ps2 to the cathode chamber 14 from the cathode liquid supply port 81 while stopping the flow of anode liquid Ps1 supplied to the anode chamber 13 from the anode liquid supply port 71. With this configuration, the pressure in the cathode chamber 14 can be raised to be higher than the pressure in the anode chamber 13 in a simple manner.

[0082] Step S20 may be executed for a predetermined time ("second processing time"), for example. The specific value of this second processing time is not particularly limited, but for example, a time sufficient to move the bubbles Bu collected in step S10 to the outer edge 61c of the diaphragm 61 can be determined by experimentation and used. This second processing time may be stored in the memory device 802 in advance.

[0083] Next, the control module 800 executes the third process related to step S30. In this third process, the control module 800 draws the bubbles Bu that moved to the outer edge 61c of the diaphragm 61 in step S20 into the anode liquid outlet 72 and discharges them from the anode chamber 13.

[0084] Furthermore, if the anode liquid pump 74 is stopped before step S30 is executed, it is preferable that the control module 800 operates the anode liquid pump 74 in step S30 to draw the bubbles Bu into the anode liquid outlet 72. Also, it is preferable that step S30 is executed with the diaphragm 61 protruding downward.

[0085] Step S30 only needs to be performed for a predetermined time ("third processing time"). The specific value of this third processing time is not particularly limited, but for example, a sufficient time for the bubbles Bu that have moved to the outer edge 61c of the diaphragm 61 to be discharged from the anode liquid outlet 72 can be determined by experimentation and used. This third processing time can be stored in the storage device 802 in advance.

[0086] Furthermore, once step S30 is completed, the control module 800 should return the pressure in the anode chamber 13 and the pressure in the cathode chamber 14 to their initial state (the state before step S10 was executed). Specifically, in this embodiment, the control module 800 equalizes the pressure in the anode chamber 13 and the pressure in the cathode chamber 14 after step S30 is completed. This returns the diaphragm 61 to a state where it does not protrude upward or downward.

[0087] Furthermore, when removing air bubbles, the control module 800 may perform the series of processes in steps S10, S20, and S30 only once, or it may perform them multiple times.

[0088] According to this embodiment as described above, by performing steps S10 to S30 described above, it is possible to suppress the accumulation of air bubbles Bu on the lower surface 61b of the diaphragm 61, thereby suppressing deterioration of the plating quality of the substrate Wf due to air bubbles Bu.

[0089] In particular, according to this embodiment, the above-described effects can be obtained simply by changing the control mode of the anode liquid circulation device 70 and the cathode liquid circulation device 80 to the control mode of this embodiment compared to a known plating apparatus 1000 having an anode liquid circulation device 70 and a cathode liquid circulation device 80. In this respect, this embodiment can be easily implemented.

[0090] Furthermore, according to this embodiment, even if there is a partially bent portion of the diaphragm 61, and as a result, bubbles Bu accumulate in this bent portion, the execution of steps S10 to S30 described above will move the bubbles Bu in this bent portion to the outer peripheral edge 61c of the diaphragm 61 and discharge it to the outside of the anode chamber 13.

[0091] Although embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various further modifications and changes are possible within the scope of the gist of the present invention as described in the claims.

[0092] 10 Plating tank 13 Anode chamber 14 Cathode chamber 60 Anode 61 Diaphragm 71 Anode solution supply port 72 Anode solution outlet 81 Cathode solution supply port 82 Cathode solution outlet 1000 Plating apparatus Bu Bubbles Ps1 Anode solution Ps2 Cathode solution Wf Substrate

Claims

1. A method for removing bubbles from a plating apparatus, wherein the plating apparatus comprises a plating tank, a diaphragm is provided inside the plating tank, the inside of the plating tank is divided by the diaphragm into an anode chamber below the diaphragm and a cathode chamber above the diaphragm, an anode is placed in the anode chamber, and a substrate as a cathode is placed in the cathode chamber facing the anode, and the bubble removal method comprises: performing a first process of increasing the pressure in the anode chamber to a higher pressure than the pressure in the cathode chamber to cause the diaphragm to protrude upward and collect bubbles on the lower surface of the portion of the diaphragm that protrudes upward; performing a second process of increasing the pressure in the cathode chamber to a higher pressure than the pressure in the anode chamber to cause the diaphragm to protrude downward and move the bubbles to the outer edge of the diaphragm; and performing a third process of drawing the bubbles that have moved to the outer edge of the diaphragm into an anode liquid outlet located in the anode chamber and discharging them from the anode chamber.

2. The method for removing bubbles in a plating apparatus according to claim 1, wherein the pressure in the anode chamber is made higher than the pressure in the cathode chamber in the first process, the flow rate of the anode liquid supplied to the anode chamber from an anode liquid supply port located in the anode chamber is greater than the flow rate of the cathode liquid supplied to the cathode chamber from a cathode liquid supply port located in the cathode chamber.

3. The method for removing bubbles in a plating apparatus according to claim 2, wherein the second process involves making the pressure in the cathode chamber higher than the pressure in the anode chamber, and further comprising making the flow rate of the cathode liquid supplied from the cathode liquid supply port to the cathode chamber greater than the flow rate of the anode liquid supplied from the anode liquid supply port to the anode chamber.

4. The method for removing bubbles in a plating apparatus according to claim 2, wherein, in the first process, the pressure in the anode chamber is made higher than the pressure in the cathode chamber by supplying anode liquid from the anode liquid supply port to the anode chamber while stopping the flow of cathode liquid supplied from the cathode liquid supply port to the cathode chamber.

5. The method for removing bubbles in a plating apparatus according to claim 3, wherein, in the second process, the pressure in the cathode chamber is made higher than the pressure in the anode chamber by supplying cathode liquid to the cathode chamber from the cathode liquid supply port while stopping the flow of anode liquid supplied to the anode chamber from the anode liquid supply port.

6. The method for removing bubbles from a plating apparatus according to claim 5, wherein the diaphragm is arranged to be inclined with respect to the horizontal direction, and the anode liquid outlet is located directly below the uppermost portion of the inclined outer edge of the diaphragm.

7. The method for removing bubbles from a plating apparatus according to claim 6, wherein the plating apparatus comprises a holding member for holding the outer edge of the diaphragm, and the anode liquid outlet is positioned directly below the uppermost portion so as to be in contact with the holding member.

8. The method for removing bubbles from a plating apparatus according to claim 7, wherein a plurality of anode liquid supply ports are provided along the outer peripheral edge of the diaphragm.

9. The method for removing bubbles from a plating apparatus according to claim 8, wherein at least one of the plurality of anode liquid supply ports is arranged to be in contact with the holding member.

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