JP2009293088A - Electroplating device and electroplating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plating device and a plating method by which a uniform plating film is formed while suppressing the generation of voids. <P>SOLUTION: The electroplating device possesses a holder 20, a plating bath 10, a power source 70 and a switch circuit 23. The holder 20 holds a semiconductor wafer 30 having a body 40 to be plated. The plating bath 10 holds a plating liquid 100 including an anode electrode 50. The power source 70 supplies constant voltage between the body 40 to be plated and the anode electrode. The switch circuit 23 is connected to the power source 70 in parallel to the body 40 to be plated. The holder 20 is provided with a dummy cathode electrode 22 connected to the power source 70 through the switch circuit 23. The dummy cathode electrode 22 is provided to be exposed at a position to be in contact with the plating solution 100 prior to the body 40 to be plated when the holder 20 is immersed in the plating solution 100. The switch circuit 23 cuts the connection of the power source 70 to the dummy cathode electrode 22 after the dummy cathode electrode 22 is brought into contact with the plating solution 100. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electroplating apparatus for plating on a semiconductor wafer and an electroplating method.

  In a wiring formation process using a Cu damascene method for a semiconductor wafer, improvement in embedding performance in vias and trenches is required as the wiring pattern becomes finer. An electroplating method is employed as a method for embedding Cu in a via or a trench. In this electroplating method, in order to realize the improvement of the embedding performance, in the prior art, a technique has been adopted in which the Cu seed film is thinned to suppress the overhang of the via or the trench.

  The Cu seed film dissolves when it comes into contact with a Cu plating solution that is a strong acid. For this reason, in the prior art, a technique for preventing dissolution of the Cu seed film is performed by immediately starting film formation by flowing a large current at the moment when the Cu seed film is deposited (contacted) with the Cu plating solution. ing. In this case, it is necessary to apply a voltage (standby voltage) between the anode electrode and the cathode electrode (Cu seed film) in the Cu plating solution before the Cu seed film is deposited on the Cu plating solution.

  In the electroplating process, a method for suppressing the dissolution of the seed film by applying a standby voltage before immersing the film to be plated in the plating solution and forming uniform plating without voids is disclosed in, for example, JP-A-2003-129294. (See Patent Document 1).

  On the other hand, when the semiconductor wafer is immersed in the plating solution, bubbles may remain on the surface to be plated such as vias and trenches. For this reason, when the semiconductor wafer is immersed in the plating solution, a method of inclining the semiconductor wafer with respect to the liquid surface and entering the bath is employed.

  The details of the plating apparatus according to the prior art will be described with reference to FIGS. 1A to 2. 1A to 1C are diagrams showing the configuration and operation of a Cu plating apparatus according to the prior art. Referring to FIG. 1A, a conventional Cu plating apparatus includes a plating tank 10, a wafer holder 120, a holder control device 60, and a power source 170. The plating tank 10 includes an inner tank 11 and an outer tank 12, and a Cu anode electrode 50 and a plating solution jet 13 for feeding the plating solution 100 to the inner tank 11 are provided on the bottom surface of the inner tank 11. Yes. Further, in order to discard the plating solution 100 overflowing from the inner tank 11, a plating solution drain port 14 is provided on the bottom surface of the outer tank 14.

  The wafer holder 120 holds the wafer 30 having the Cu seed film 40 formed on the surface thereof. The Cu seed film 40 is connected to the power source 170 via the contact 21 (conducting electrode) in the outer peripheral region of the wafer 30. The processing surface (Cu seed film 40) of the wafer 30 is held on the bottom surface of the wafer holder 120 so as to be exposed downward in the Y-axis of the drawing (direction opposite to the liquid surface), and the contact 21 is sealed with an O ring (not shown). Sealed with a member. The power source 170 applies a constant voltage between the Cu anode electrode 50 and the Cu seed film 40 (cathode). The holder control device 60 controls the raising / lowering, rotation, and tilting of the wafer holder 120.

  In the conventional plating apparatus, a constant voltage (standby voltage) is applied between the Cu anode electrode 50 and the Cu seed film 40 before the wafer 30 is immersed in the plating solution. The wafer 30 is inserted (entered) into the plating solution 100 while maintaining the state where the standby voltage is applied. At this time, referring to FIG. 1B, wafer holder 120 is inclined at a predetermined angle with respect to the liquid surface, and is lowered while rotating and inserted into plating solution 100. Thereby, bubbles existing in a portion to be plated such as a via or a trench on the surface of the wafer 30 can be removed.

  From the moment when the Cu seed film 40 comes into contact with (plating) the plating solution 100, Cu is deposited on the surface of the Cu seed film 40, and Cu is dissolved on the surface of the anode electrode 50 to start the plating process. Immediately after the Cu seed film 40 is deposited, the power source 170 is switched from constant voltage control to constant current control for the purpose of stabilizing various characteristics of the plating film.

  As described above, in the conventional plating apparatus, the Cu seed film is dissolved at the time of contact with the plating solution by applying a standby voltage between the Cu plating layer and the anode electrode before being immersed in the plating solution. Can be prevented. Further, by dipping the semiconductor wafer in an inclined manner with respect to the surface of the plating solution and rotating, it is possible to remove bubbles remaining on the surface to be plated. As described above, according to the plating apparatus as shown in FIG. 1A, dissolution of the Cu seed film and generation of voids due to bubbles can be suppressed, and a stable Cu film can be formed.

JP 2003-129294 A

In recent years, with the miniaturization of technology, the Cu seed film 40 has been made thinner. For this reason, in order to prevent dissolution of the thinned Cu seed film 40, a larger initial current flows by applying a larger voltage (standby voltage) between the Cu seed film 40 (cathode) and the Cu anode electrode 50. There is a need. For example, in an average Cu seed film having a film thickness of 65 nm, when the initial current density of Cu plating is about 30 A / m ² , the Cu seed film on the via or trench sidewall is dissolved, and voids are formed in the via or trench. appear. In order to prevent this, a standby voltage for generating an initial plating current density larger than 30 A / m ² is necessary.

  On the other hand, in the plating method in which the semiconductor wafer is inclined and immersed, the peripheral portion of the semiconductor wafer is deposited on the plating solution before the central portion. Referring to FIG. 1B, the region (contact region 200) where Cu seed film 40 and plating solution 100 first contact each other has a smaller area than the entire Cu seed film 40. At this time, when a large standby voltage is applied between the Cu seed film 40 (cathode) and the Cu anode electrode 50, current concentrates in the contact region 200, resulting in a high current density.

  FIG. 2 is a diagram showing a time transition of the current density I flowing through the Cu seed film 40. At time T <b> 1 when the Cu seed film 40 contacts the plating solution 100, the current concentrates on the contact region 200. That is, at time T1, the current density I increases and a large current flows through the contact region 200. Thereafter, when another region is immersed in the plating solution 100, the current path is dispersed, so that the current density I decreases. At time T2, a predetermined area (for example, all areas) as shown in FIG. 1C. The Cu seed film 40 is immersed, and the current density I becomes a constant value. The period from time T1 to time T2 is short, but during this time, the amount of current flowing in the contact region 200 is larger than that in other regions. The amount of precipitation per unit area (proportional to the thickness of the plated metal film) is a value corresponding to the amount of current per unit area. Therefore, more copper is deposited in the contact region 200, that is, in the peripheral region of the semiconductor wafer than in other regions.

  As described above, in the plating apparatus according to the prior art, an excessive current is generated in a region where the plating solution first comes into contact, and copper is abnormally precipitated. As a result, the amount of plating embedded in the peripheral portion of the semiconductor wafer is greater than that in the central portion, and the thickness of the plating film formed on the entire wafer becomes non-uniform.

  In order to solve the above problems, the present invention employs the means described below. In the description of technical matters constituting the means, in order to clarify the correspondence between the description of [Claims] and the description of [Best Mode for Carrying Out the Invention] Number / symbol used in the best mode for doing this is added. However, the added number / symbol should not be used to limit the technical scope of the invention described in [Claims].

  The electroplating apparatus according to the present invention includes a holder (20), a plating tank (10), a power source (70), and a switch circuit (23). The holder (20) holds the semiconductor wafer (30) having the object to be plated (40). The plating bath (10) holds the plating solution (100) including the anode electrode (50). The power source (70) supplies a constant voltage between the object to be plated (40) and the anode electrode. The switch circuit (23) is connected to the object to be plated (40) in parallel with the power source (70). The holder (20) includes a dummy cathode electrode (22) connected to the power source (70) via the switch circuit (23). When the holder (20) is immersed in the plating solution (100), the dummy cathode electrode (22) is exposed and provided at a position in contact with the plating solution (100) prior to the object to be plated (40). The switch circuit (23) cuts off the connection between the power source (70) and the dummy cathode electrode (22) after the dummy cathode electrode (22) contacts the plating solution (100).

  Thus, the object to be plated (40) and the dummy cathode electrode (22) are connected in parallel to the power source (70), and the dummy cathode electrode (22) contacts the plating solution (100) before the object to be plated (40). Therefore, current concentrates on the dummy cathode electrode (22) at the beginning of liquid contact. For this reason, abnormal deposition of the metal to be plated occurs at the dummy cathode electrode (22). Moreover, since the current density also decreases when the object to be plated (40) comes into contact with the plating solution (100), abnormal deposition on the object to be plated (40) can be suppressed. Further, when the switch circuit (23) is turned off, the metal deposited on the surface of the object to be plated (40) is dissolved in the plating solution (100) and returns to the surface state before plating.

  The electroplating method according to the present invention is an electroplating method performed by using the above-described electroplating apparatus, and is defined between the object to be plated (40) and the dummy cathode electrode (22) and the anode electrode (50). While supplying voltage, the step of immersing the dummy cathode (22) in the plating solution (100) prior to the object to be plated (40) and the dummy cathode electrode (2) after contacting the plating solution (100) Cutting off the supply of constant voltage to the cathode electrode (22).

  According to the electroplating apparatus and the electroplating method of the present invention, it is possible to form a uniform plating film while suppressing the generation of voids.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same or similar reference numerals indicate the same, similar, or equivalent components.

(Constitution)
The details of the configuration of the plating apparatus according to the present invention will be described with reference to FIGS. 3A, 4, and 5. 3A to 3C are diagrams showing the configuration and operation of the Cu plating apparatus according to the present invention. The plating apparatus according to the present invention includes a plating tank 10, a wafer holder 20, a holder control device 60, and a power source 70. The plating tank 10 includes an inner tank 11 that holds the plating solution 100 and an outer tank 12 that holds the plating solution 100 that has overflowed from the inner tank 11. A Cu anode electrode 50 and a plating solution jet port 13 for feeding the plating solution 100 to the inner vessel 11 are provided on the bottom surface in the inner vessel 11. Further, in order to discard the plating solution 100 overflowed from the inner tank 11, a plating solution drain port 14 is provided on the bottom surface of the outer tank 14.

  The wafer holder 20 holds a semiconductor wafer 30 (hereinafter referred to as a wafer 30) having a Cu seed film 40, which is an object to be plated, formed on the surface thereof. The Cu seed film 40 is connected to the power source 70 via the contact 21 (conducting electrode) in the outer peripheral region of the wafer 30. The processing surface (Cu seed film 40) of the wafer 30 is held on the bottom surface of the wafer holder 20 so as to be exposed downward in the drawing Y-axis (direction facing the liquid surface). The contact 21 is sealed with a sealing member such as an O-ring (not shown).

  The wafer holder 20 according to the present invention further includes a dummy cathode electrode 22 and a switch circuit 23. The dummy cathode electrode 22 is embedded in the bottom surface of the wafer holder 20 and is connected to the power source 70 via the switch circuit 23. FIG. 4 is a plan view showing a bottom structure when the wafer holder is viewed from below in the Y-axis direction (wafer side). Referring to FIGS. 3A and 4, dummy cathode electrode 22 is disposed on the outer peripheral portion of wafer holder 23 so as to be partially exposed to the surface to be plated. Further, it is preferable that the dummy cathode electrode 22 is provided separately in a region outside the wafer 30 to be held. Furthermore, the shape of the dummy cathode electrode 22 is preferably a shape in which the distance from the wafer 30 is uniform. Since the wafer 30 is usually circular, the shape is preferably circular (ring shape). The contact 21 is formed in a contact formation region 25 on the outer edge portion of the wafer 20.

  The dummy cathode electrode 22 may be formed of one electrode (metal plate or metal film) so as to surround the wafer 30 as shown in FIG. 4, or a plurality of electrodes (metals) as shown in FIG. Plate or metal film). In this case, each of the plurality of electrodes is commonly connected to one end of the switch circuit 23. Although not shown, the dummy cathode electrode 22 may be configured by wiring as long as the exposed portion serving as the plated surface has a certain surface area. When the dummy cathode electrode 22 is provided on the outer peripheral portion of the wafer 30, the diameter of the dummy cathode electrode 22 needs to be larger than the diameter of the wafer. At present, since 300 mm wafers are becoming mainstream, it is necessary to provide a dummy cathode electrode 22 having a diameter larger than 300 mm. However, the dummy cathode electrode 22 having such a size and a uniform surface is difficult to construct from a manufacturing viewpoint and is expensive. For this reason, if the dummy cathode electrode 22 is comprised by the metal plate (metal film) divided | segmented into plurality like the example shown in FIG. 5, a highly accurate and low-cost member supply will be attained.

  The material of the dummy cathode electrode 22 is preferably a metal that is resistant to sulfuric acid in the plating solution 100, such as Pt, Ti, or SUS. As for the size of the dummy cathode electrode 22, it is preferable that the inner diameter is 1 mm to 10 mm larger than the wafer diameter, and the width in the radial direction needs to be larger than the region where copper is abnormally deposited when contacting the plating solution 100. That is, the size of the dummy cathode electrode 22 (surface area to be plated) is set so that the current density when the wafer 30 (Cu seed film 40) is deposited is a size that does not cause abnormal precipitation of copper. It is preferable to do. Therefore, the radial width of the dummy cathode electrode 22 is preferably 5 mm to 20 mm.

  The switch circuit 23 is connected between the power source 70 and the dummy cathode electrode 22 and controls the connection between the power source 70 and the dummy cathode electrode 22. When the switch circuit 23 is in the ON state, the dummy cathode electrode 22 and the contact 21 (Cu seed film 40) are commonly connected to the power source. At this time, the power source 70 applies a common constant voltage to the dummy cathode electrode 22 and the Cu seed film 40. When the switch circuit 23 is in an off state, the connection between the dummy cathode electrode 22 and the power source 70 is disconnected. The switch circuit 23 may be provided outside the wafer holder 20.

  The power source 70 applies a constant voltage between the Cu anode electrode 50 and the Cu seed film 40 (cathode) or the dummy cathode electrode 22. The power source 70 applies a high voltage to the Cu anode electrode 50 and a low voltage to the Cu seed film 40 (cathode) or the dummy cathode electrode 22. Further, for the purpose of stabilizing various characteristics of the plating film, the power source 70 is switched from constant voltage control to constant current control after the Cu seed film 40 is deposited on the plating solution 100. This switching is executed when the liquid landing area of the Cu seed film 40 reaches a predetermined value. For example, switching from constant voltage control to constant current control may be performed according to the value of the current flowing through the Cu seed film 40, or may be performed according to the time counted from the start of the plating process. Normally, the power source 70 is switched from constant voltage control to constant current control when the entire surface of the Cu seed film 40 is deposited on the plating solution 100. The switching control may be performed simultaneously with the disconnection control of the switch circuit 23.

  The holder control device 60 controls the raising / lowering, rotation, and tilting of the wafer holder 20. 3A to 3C, when the gravity direction is the Y axis and the liquid surface direction is the X axis, the wafer holder 20 moves up and down in the Y axis direction, rotates around the A axis, and forms a predetermined angle with respect to the X axis. The wafer 30 is inclined so that the surface of the wafer 30 is parallel to the B axis. The holder control device 60 according to the present invention moves into the plating tank 10 while the wafer holder 20 is tilted and rotated, and is immersed in the plating solution 100. When all of the Cu seed film 40 is immersed in the plating solution 100, the holder control device 60 controls the wafer holder 20 so that the wafer 30 is parallel to the liquid surface (Cu anode electrode 50).

(Operation)
The details of the plating processing operation of the plating apparatus according to the present invention will be described with reference to FIGS. 3A to 3C and FIG. First, before the wafer holder 20 comes into contact with the Cu plating solution 100, a constant voltage (standby voltage) is supplied from the power source 70 so that the Cu anode electrode 50 becomes the anode, the dummy cathode electrode 22, and the Cu seed film 40 become the cathode. Is applied (see FIG. 6, time T0). At this time, the switch circuit 23 is controlled to be on.

  Referring to FIG. 3A, wafer holder 20 is inclined at a predetermined angle with respect to plating solution 100 and descends into plating tank 10 while rotating (see FIG. 6, time T0 to time T1). At this time, the wafer holder 20 is lowered into the plating tank 10 while the standby voltage is applied between the Cu seed film 40 and the Cu anode electrode 50.

  Referring to FIG. 3B, at time T1, wafer holder 20 comes into contact (plating) with plating solution 100. At this time, since the wafer holder 20 is inclined (B-axis direction) with respect to the liquid surface (X-axis direction) of the plating solution, the dummy cathode electrode 22 is placed before the Cu seed film 40 which is the surface to be plated. 100 is contacted. From the moment when the dummy cathode electrode 23 is deposited, copper starts to be deposited on the dummy cathode electrode 30, and on the surface of the anode electrode 50, copper starts to dissolve and plating is performed. Referring to FIG. 6, since a certain standby voltage is applied to dummy cathode electrode 22, current concentrates on dummy cathode electrode 22 at time T <b> 1 when it comes into contact with plating solution 100. For this reason, at time T1, copper is abnormally deposited on the surface of the dummy cathode electrode 22 in contact with the plating solution 100 due to the large current density I.

  When the wafer holder 20 continues to descend, the contact area between the dummy cathode electrode 22 and the plating solution 100 increases, and the Cu seed film 40 contacts the plating solution 100 (see FIG. 6, time T2). From the moment when the Cu seed film 40 is deposited, copper starts to precipitate on the surface of the Cu seed film, and copper starts to dissolve on the surface of the anode electrode 50 to perform plating. As the wafer holder 20 descends (time elapses), the area of the dummy cathode electrode 22 that is deposited on the plating solution 100 increases, so the current density I flowing between the dummy cathode electrode 22 and the anode electrode 50 decreases. As a result, the current density I at time T2 when the Cu seed film 22 contacts the plating solution 100 is large enough to suppress the abnormal precipitation of copper.

  Further, when the wafer holder 20 is lowered, the area of the cathode (dummy cathode electrode 22 and Cu seed film 22) landing on the plating solution 100 increases, so that the current density I flowing between the cathode and anode electrode 50 decreases. Referring to FIG. 3C, when a predetermined area in Cu seed film 40 is immersed in the plating solution, switch circuit 23 is controlled to be turned off, and connection between dummy cathode electrode 22 and power supply 70 is established. It is blocked (see FIG. 6, time T3). For example, when the current density I becomes a predetermined current density it, the switch circuit 23 is controlled to be turned off. Alternatively, the switch circuit 23 is controlled to be turned off when all of the Cu seed film 40 is immersed in the plating solution 100. Thus, the on / off control of the switch circuit 23 may be performed according to the current density I, or may be performed according to the passage of time from the start of lowering of the wafer holder 20. Usually, the time from the contact time T1 between the wafer holder 20 and the plating solution 100 to the immersion of all of the Cu seed film 40 is a short time (order of microseconds). For this reason, the switch circuit 23 is preferably controlled so that the wafer holder 20 is turned off immediately after contacting the wafer liquid 100.

  When the connection between the dummy cathode electrode 23 and the Cu anode electrode 50 is cut off by the switch circuit 23, the dummy cathode electrode 23 immersed in the plating solution 100 is reduced by the time T3, so that the current density I increases. However, since the area of the dummy cathode electrode 23 is smaller than the area of the Cu seed film 40, the increase in the current density I is small and does not affect the plating process.

  At the same time T3 when the switch circuit 23 is turned off, the power source 70 is switched from constant voltage control to constant current control. Thereby, various characteristics of the plating film are stabilized. Further, before and after this, the wafer holder 20 shifts from an inclined state to a state (horizontal state) parallel to the (Cu anode electrode 50). Since the wafer 30 and the Cu anode electrode 50 are in a parallel state, a uniform plating process can be performed. The switching control from the constant voltage control to the constant current control for the power source 70 may be performed simultaneously with time T3 or may be performed at time T4 when the current density I is stabilized. Further, at time T4 when the current density I is stabilized, the wafer 30 and the Cu anode electrode 50 may be controlled to be parallel.

  When the switch circuit 23 is turned off, Cu plating film formation under constant current control is continued on the surface of the Cu seed film 40, and Cu slightly deposited on the surface of the dummy cathode electrode 30 during the period up to time T3 is the plating solution 100. It dissolves in and returns to the surface state before Cu plating. Further, during the plating process for the Cu seed film 40, the current flowing through the dummy cathode electrode 23 is cut off by the switch circuit 23. Thereby, the electric field in the peripheral region of the dummy cathode electrode 23 in the wafer 30 and the central region of the wafer 30 becomes uniform, and the film thickness of the plating film can be made uniform.

  As described above, in the present invention, the contact 21 and the dummy cathode electrode 22 connected to the Cu seed film 40 are connected in parallel between the power source 70 and the Cu add electrode 50 in the plating solution 100, and a constant voltage is applied. Is applied. Thereby, the dummy cathode electrode 22 becomes a surface to be plated together with the Cu seed film 40. That is, the current density flowing on the surface to be plated during the plating process is a value corresponding to the areas of the Cu seed film 40 and the dummy cathode electrode 22 that have been deposited on the plating solution 100. In the plating apparatus according to the present invention, since the dummy cathode electrode 22 comes into contact with the plating solution 100 prior to the Cu seed film 40 which is a desired surface to be plated, a large current density is generated in the dummy cathode electrode 22. Further, when the Cu seed film 40 comes into contact with the plating solution 100, a part of the dummy cathode electrode 22 is already immersed in the plating solution 100, so that the current density is reduced compared to the initial contact. From the above, the abnormal precipitation of copper described in the prior art occurs at the dummy cathode electrode 22 and is suppressed when the Cu seed film 40 is immersed in the plating solution 100. Therefore, in the plating apparatus according to the present invention, desired Cu plating film characteristics can be obtained. Furthermore, in the plating apparatus according to the present invention, since the surface of the wafer 30 is immersed so as to be inclined with respect to the liquid surface of the plating solution 100, a uniform plating film can be formed while suppressing the generation of voids. .

  The embodiment of the present invention has been described in detail above, but the specific configuration is not limited to the above-described embodiment, and modifications within a scope not departing from the gist of the present invention are included in the present invention. . The dummy cathode electrode 22 is preferably provided at a position protruding from the surface of the wafer 30 held by the wafer holder 20 to the plating solution 100. However, if the dummy cathode electrode 22 is deposited on the plating solution 100 prior to the wafer 30, the dummy cathode electrode 22 It may be provided on the same plane. Further, in order to prevent generation of bubbles on the surface of the dummy cathode electrode 22, it is preferable that the surface of the dummy cathode electrode 22 and the surface of the wafer holder 20 are flush with each other. Furthermore, in the present embodiment, the plating apparatus for plating copper wiring has been described, but the present invention can also be applied to a plating apparatus for plating other metal wiring (for example, gold wiring). In this case, another metal seed layer may be used instead of the Cu seed film 40 to be plated.

FIG. 1A is a diagram illustrating an example of a configuration of a plating apparatus and a plating process according to a conventional technique. FIG. 1B is a diagram illustrating an example of a configuration of a plating apparatus and a plating process according to a conventional technique. FIG. 1C is a diagram illustrating an example of a configuration of a plating apparatus and a plating process according to a conventional technique. FIG. 2 is a diagram showing the transition of current density in the plating process according to the prior art. FIG. 3A is a diagram showing a configuration and a plating method in the embodiment of the plating apparatus according to the present invention. FIG. 3B is a diagram showing a configuration and a plating method in the embodiment of the plating apparatus according to the present invention. FIG. 3C is a diagram showing a configuration and a plating method in the embodiment of the plating apparatus according to the present invention. FIG. 4 is a plan view showing an example of the bottom structure of the wafer holder according to the present invention. FIG. 5 is a plan view showing an example of the bottom structure of the wafer holder according to the present invention. FIG. 6 is a diagram showing the transition of the current density in the plating process according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Plating tank 20: Wafer holder 21: Contact 22: Dummy cathode electrode 23: Switch circuit 30: Wafer 40: Cu seed film 50: Cu anode electrode 60: Wafer holder control apparatus 100: Plating solution

Claims (8)

A holder for holding a semiconductor wafer having an object to be plated;
A plating tank for holding a plating solution containing an anode electrode;
A power source for supplying a constant voltage between the object to be plated and the anode electrode;
The switch circuit connected in parallel with the object to be plated with respect to the power source,
Comprising
The holder includes a dummy cathode electrode connected to the power source via the switch circuit,
When the holder is immersed in the plating solution, the dummy cathode electrode is provided exposed at a position in contact with the plating solution before the object to be plated,
The switch circuit is an electroplating apparatus that cuts off the connection between the power source and the dummy cathode electrode after the dummy cathode electrode is in contact with the plating solution. The electroplating apparatus according to claim 1,
The dummy cathode electrode is an electroplating apparatus provided in an outer peripheral region of the semiconductor wafer held by the holder. In the electroplating apparatus according to claim 1 or 2,
The switch circuit connects the dummy cathode electrode and the power source after the current between the cathode electrode and the power source reaches a predetermined value after the dummy cathode electrode contacts the plating solution. Shut off electroplating equipment. In the electroplating apparatus according to claim 1 or 2,
The switch circuit is an electroplating apparatus that disconnects the connection between the dummy cathode electrode and the power source when a predetermined time has elapsed after the dummy cathode electrode contacts the plating solution. The electroplating apparatus according to any one of claims 1 to 4,
The anode electrode is an electroplating apparatus containing copper. In the electroplating method performed using the electroplating apparatus of any one of Claim 1 to 5,
Immersing the dummy cathode in the plating solution prior to the object to be plated while supplying a constant voltage between each of the object to be plated and the dummy cathode electrode and the anode electrode;
Shutting off the supply of the constant voltage to the dummy cathode electrode after the dummy cathode electrode contacts the plating solution;
An electroplating method comprising: The electroplating method according to claim 6,
The step of immersing in the plating solution includes the step of immersing the holder holding the semiconductor wafer in the plating solution while keeping the surface of the semiconductor wafer and the surface of the plating solution non-parallel. Plating method. In the electroplating method according to claim 6 or 7,
Further comprising measuring a current value between the object to be plated and the anode electrode;
The step of cutting off the supply of the constant voltage includes a step of cutting off the supply of the constant voltage to the dummy cathode electrode when the current value reaches a predetermined value.

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