Plating device and plating method

Abstract

[Problem] To enhance the in-plane uniformity of the thickness of a plating film by stabilizing the current density of a plating current. [Solution] This plating device comprises: a substrate holding unit; a negative electrode that can be in contact with a substrate; a top plate that covers the substrate from above; a plating solution nozzle that is provided at the top plate and discharges a plating solution into a space between the substrate and the top plate toward the central part of the substrate; a positive electrode plate that is positioned in the plating solution filling the space, covers the substrate from above, and divides the space into an upper region and a lower region; and a power supply device that supplies a plating current between the substrate that is in contact with the negative electrode and the positive electrode plate. The positive electrode plate is provided with a plurality of communication passages that penetrate the positive electrode plate, and through the communication passages, the plating solution can flow from the upper region to the lower region. The positive electrode plate has a plurality of communication restriction regions that are provided concentrically, and in the communication restriction regions, the flow of the plating solution from the upper region to the lower region is restricted as compared with the regions other than the communication restriction regions.

Description

Plating apparatus and plating method

[0001] The present disclosure relates to a plating apparatus and a plating method.

[0002] In the manufacture of semiconductor devices, a plating process is performed in which a plating solution is filled in a substrate such as a semiconductor wafer, and an electric current is applied so as to apply a desired electric field to the plating solution, thereby depositing a plating film on the surface to be processed. The plating apparatus disclosed in Patent Document 1 includes a substrate holding unit that holds a substrate, a first electrode that contacts the substrate and conducts electricity to the surface to be processed of the substrate, and a position facing the surface to be processed of the substrate held by the substrate holding unit. And a second electrode disposed thereon, and a processing liquid supply means for supplying a processing liquid into a region sandwiched between the surface to be processed of the substrate held by the substrate holding unit and the second electrode.

[0003] Japanese Patent Application Laid-Open No. 2005-133160

[0004] The present disclosure provides a technique capable of stabilizing the current density of a plating current and enhancing the in-plane uniformity of the plating film thickness.

[0005] According to one embodiment of the present disclosure, the device comprises: a substrate holding portion for holding a substrate; a cathode that can contact the substrate held by the substrate holding portion; a top plate that covers the substrate held by the substrate holding portion from above; a plating solution nozzle provided on the top plate for discharging a plating solution into the space between the substrate and the top plate toward the center of the substrate held by the substrate holding portion; a positive electrode plate positioned in the plating solution filling the space and covering the substrate held by the substrate holding portion from above, the positive electrode plate dividing the space into an upper region above the positive electrode plate and a lower region below the positive electrode plate; and a power supply device that applies a voltage between the cathode and the positive electrode plate and causes a plating current to flow between the substrate in contact with the cathode and the positive electrode plate, wherein the positive electrode plate has a number of connecting passages that penetrate the positive electrode plate, and the plating solution can flow from the upper region to the lower region through the connecting passages. The present electrode plate has a plurality of communication restriction regions arranged concentrically, and in the communication restriction regions, the flow of the plating solution from the upper region to the lower region is restricted compared to regions other than the communication restriction regions, in a plating apparatus.

[0006] According to the above embodiment of the present disclosure, the current density of the plating current can be stabilized to improve the in-plane uniformity of the plating film thickness.

[0007] Figure 1 is a schematic longitudinal cross-sectional view showing the configuration of a plating apparatus according to the first embodiment. Figure 1 is a schematic plan view showing an example of the positional relationship of each component of the plating apparatus shown in Figure 1. Figure 2 is a schematic diagram showing an example of the planar configuration of the top plate of the plating apparatus, and is a schematic bottom view of the top plate viewed from below. Figure 3 is a schematic diagram showing an example of the cross-sectional configuration of the top plate and anode plate of the plating apparatus, and is a schematic cross-sectional view obtained by cutting the top plate and anode plate with a vertical plane passing through the rotation center of the wafer. Figure 4 is a schematic diagram showing an example of the planar configuration of the anode plate of the plating apparatus, and is a schematic plan view of the anode plate viewed from above. Figure 5 is a schematic diagram showing an example of the filling behavior of the plating solution in a comparative example without a communication restriction region. Figure 6 is a schematic diagram showing an example of the filling behavior of the plating solution in the first embodiment having a communication restriction region. Figure 7 is a schematic partial cross-sectional view of the anode plate showing one example of the configuration of the anode plate of the plating apparatus according to the second embodiment. Figure 8 is a schematic partial cross-sectional view of the anode plate showing one example of the configuration of the anode plate of the plating apparatus according to the third embodiment. Figure 9 is a schematic partial cross-sectional view of the anode plate showing another example of the configuration of the anode plate of the plating apparatus according to the third embodiment. Figure 10 is a schematic partial cross-sectional view of the anode plate showing yet another example of the configuration of the anode plate of the plating apparatus according to the third embodiment. This is a schematic diagram illustrating an example of the operation of a plating apparatus that fills a plating solution while moving the positive electrode plate up and down.

[0008] The following describes an embodiment of the plating apparatus with reference to the attached drawings.

[0009] <First Embodiment> The plating apparatus 1 according to the first embodiment is configured as a single-wafer electroplating apparatus. As shown in Figure 1, the plating apparatus 1 is equipped with a substrate holding and rotating section 10, also known as a spin chuck. The substrate holding and rotating section 10 has a substrate holding section 12 that holds a substrate such as a semiconductor wafer (hereinafter simply referred to as "wafer W") in a horizontal position, and a rotation drive section 14 that rotates the substrate holding section 12 around a vertical axis. In the illustrated embodiment, the substrate holding section 12 is configured as a vacuum chuck that vacuum-adsorbs the central part of the lower surface of the wafer W.

[0010] The plating apparatus 1 has a top plate 20 that covers the entire upper surface of the wafer W held by the substrate holding rotation unit 10. The top plate 20 is a substantially disc-shaped member with a diameter larger than the diameter of the wafer W. A plating solution nozzle 21 is provided in the center of the top plate 20. The plating solution nozzle 21 has a discharge port for the plating solution that faces the wafer W. The plating solution nozzle 21 may be a through hole formed in the top plate 20 itself, or it may be a nozzle body mounted in the center of the top plate 20. A plating solution supply unit 22 is connected to the plating solution nozzle 21.

[0011] The plating solution supply unit 22 includes a plating solution supply source 23 such as a tank for storing the plating solution, piping 24 connecting the plating solution supply source 23 and the plating solution nozzle 21, and flow control equipment 25 such as an on-off valve, a flow control valve, and a flow meter (shown as a single box in Figure 1) interposed in the piping 24.

[0012] The top plate 20 can be raised and lowered by the top plate lifting drive unit 26. The top plate lifting drive unit 26 consists of a linear actuator such as an air cylinder. The top plate 20 is attached to the tip of the lifting rod 27 of the top plate lifting drive unit 26.

[0013] As shown in Figures 3 and 4, a plurality of circular grooves 28 are formed concentrically on the underside of the top plate 20. In one embodiment, the width of each groove 28 measured radially on the top plate 20 is, for example, 2 mm, the depth of each groove 28 is, for example, 1 mm, and the distance between adjacent grooves in the radial direction may be, for example, greater than the width of one groove, and can be 7 mm. However, the dimensions of the grooves 28 are not limited to the above values.

[0014] As shown in Figures 1 and 4, a positive electrode plate (anode) 30 is provided above the wafer W held in the substrate holding section 12 and below the top plate 20. The positive electrode plate 30 can be raised and lowered by a positive electrode plate lifting drive unit having the same configuration as the top plate lifting drive unit 26. The positive electrode plate lifting drive unit has a positive electrode plate support portion 131 provided at the tip of a lifting rod 135 that is raised and lowered by a linear actuator 134. The positive electrode plate 30 is, for example, a circular member having a size that can completely cover the wafer W in a plan view. The top plate 20 is, for example, a circular member having a size that can completely cover the positive electrode plate 30 in a plan view. The positive electrode plate 30 divides the space between the upper surface of the wafer W held in the substrate holding section 12 and the lower surface of the top plate 20 into an upper region SA above the positive electrode plate 30 and a lower region SB below the positive electrode plate 30.

[0015] For example, a titanium plate coated with iridium oxide can be used as the material for the positive electrode plate 30.

[0016] The positive electrode plate 30 has numerous connecting passages 31 (only a portion of which are shown as small circles in Figure 5) that connect the upper and lower sides of the positive electrode plate 30. Through these connecting passages 31, the plating solution discharged from the plating solution nozzle 21 can flow from the upper region SA to the lower region SB. In one embodiment, the positive electrode plate 30 has a perforated plate-like (or perforated metal-like) form with numerous through holes (also called "through holes 31") that serve as the connecting passages 31, and the numerous through holes are preferably evenly distributed according to a predetermined arrangement pattern.

[0017] Furthermore, the positive electrode plate 30 has a plurality of ring-shaped communication restriction regions 32 arranged concentrically, and in each communication restriction region, the flow of the plating solution from the upper region SA to the lower region SB is restricted compared to the region 33 other than the communication restriction region. In one embodiment in which the positive electrode plate 30 has a perforated plate-like shape, the communication restriction region 32 can be a region without through holes. In such a communication restriction region 32, the flow of the plating solution from the upper region SA to the lower region SB is restricted to zero. Note that the region 33 other than the communication restriction region (hereinafter also referred to as the "unrestricted region 33" for simplicity) can be a region in which through holes are evenly distributed according to a predetermined arrangement pattern.

[0018] The area directly below the plating solution nozzle 21 on the positive electrode plate 30 is an unrestricted area 33.

[0019] In one embodiment, the positive electrode plate 30 has a perforated plate-like shape, the communication restriction region 32 may be a region with a smaller opening ratio (of through holes) than the non-restricted region 33. In other words, in this case, the flow rate of the plating solution from the upper region SA to the lower region SB in the communication restriction region 32 is limited to a value smaller than the flow rate of the plating solution from the upper region SA to the lower region SB in the non-restricted region 33. Specifically, for example, the arrangement pitch of through holes or the number of through holes per unit area in the communication restriction region 32 and the non-restricted region 33 may be the same, and the hole diameter (size) of each through hole in the communication restriction region 32 may be smaller than the hole diameter of each through hole in the non-restricted region 33. Alternatively, for example, the sizes of each through hole in the communication restriction region 32 and the non-restricted region 33 may be the same, and the number of through holes per unit area in the communication restriction region 32 may be less than that in the non-restricted region 33.

[0020] In one embodiment, the through-holes (connecting passages 31) provided in the unrestricted region 33 can be arranged in a 60-degree staggered pattern. A 60-degree staggered pattern means that six through-holes adjacent to any one through-hole are located at the vertices of a regular hexagon centered on the one through-hole. In one example, the diameter of the through-holes is 1 mm and the pitch of the through-holes is 2.5 mm (but is not limited to this). The arrangement of the through-holes is not limited to a 60-degree staggered pattern, but may also be other regular arrangements, such as a 45-degree staggered pattern (meaning that four through-holes adjacent to any one through-hole are located at the vertices of a square centered on the one through-hole).

[0021] In one embodiment, where the positive electrode plate 30 has a perforated plate-like shape and the communication restriction region 32 is a region without through holes, if the radial width of one communication restriction region 32 is made too wide, there is a risk that an appropriate plating current density cannot be obtained near that communication restriction region 32. For this reason, it is preferable that the radial width of the communication restriction region 32 be smaller than the radial width of the unrestricted region 33. Furthermore, it is preferable that the radial width of the communication restriction region 32 be less than 10 mm.

[0022] As shown in Figures 1 and 2, a pair of semi-circular cathode contact portions 40 are provided so as to be located near the outer edge of the wafer W held by the substrate holding portion 12. The cathode contact portions 40 can move horizontally toward the outer edge of the wafer W by a cathode moving mechanism 42 (see arrow Ch in Figures 1 and 2). This allows the cathode contact portions 40 to move between a processing position in contact with the outer edge of the wafer W and a standby position away from the wafer W. The cathode moving mechanism 42 can be composed of, for example, a pair of linear actuators, each of which moves the cathode contact portion 40.

[0023] Each cathode contact portion 40 is connected to, for example, one wire 43 (shown as one on the left side in Figure 1), and this wire 43 is connected to the negative terminal of the power supply unit 50. Each cathode contact portion 40 has a plurality of cathode terminals 44 that electrically contact the seed layer formed on the surface of the wafer W when in the processing position. The cathode contact portion 40 may include a mechanism (not shown) that presses the cathode terminals 44 against the seed layer formed on the surface of the wafer W. The plurality of cathode terminals 44 are provided at intervals along the circumferential direction of the outer edge of the wafer W, preferably at approximately equal intervals. Each cathode contact portion 40 is provided with a plurality of wires (not shown) electrically connected to each of the cathode terminals 44 provided on the cathode contact portion 40, thereby electrically connecting the cathode terminals 44 to the negative terminal of the power supply unit 50.

[0024] A cleaning solution supply unit 60 is also connected to the plating solution nozzle 21. The cleaning solution supply unit 60 includes a cleaning solution supply source 61, piping 62 connecting the cleaning solution supply source 61 and the plating solution nozzle 21, and flow control equipment 63 such as an on-off valve, a flow control valve, and a flow meter interposed in the piping 62. In the illustrated embodiment, a three-way valve 64 is provided in the middle of the piping 24 that supplies the plating solution from a tank (plating solution supply source) 23 that stores the plating solution to the plating solution nozzle 21, and the piping 62 is connected to this three-way valve 64. As a result, by switching the three-way valve 64, it is possible to selectively supply either the plating solution or the cleaning solution to the plating solution nozzle 21 on the top plate 20. Instead of the three-way valve 64, on-off valves may be provided on the piping 24 and 62, respectively. The cleaning solution is, for example, DIW (pure water), and the cleaning solution supply source 61 is a DIW supply source provided as factory power.

[0025] The plating apparatus 1 is equipped with a cleaning solution nozzle 70. The cleaning solution nozzle 70 is held by a nozzle arm 72 (see Figure 2) and can move between a position directly above the center of the wafer W held by the substrate holding section 12 (cleaning position) and a standby position outside the wafer W in a plan view (see arrow Dh in Figure 2). The cleaning solution nozzle 70 can also be supplied with cleaning solution from a cleaning solution supply source 61 via piping 66 and flow control equipment 65 such as on-off valves, flow control valves, and flow meters.

[0026] The plating apparatus 1 includes a control unit 80. The control unit 80 can control the operation of all operable components included in the plating apparatus 1. The control unit 80 is, for example, a computer and includes a control calculation unit 81 and a storage unit 82. The storage unit 82 stores programs (including processing recipes) that control various processes performed in the plating apparatus 1. The control calculation unit 81 controls the operation of the plating apparatus 1 by reading and executing the programs stored in the storage unit 82. The control calculation unit 18 may be a CPU (Central Processing Unit) and may be one or more circuits.

[0027] Furthermore, such a program may have been recorded on a storage medium readable by a computer and installed from that storage medium to the storage unit 82 of the control unit 80. The storage medium readable by a computer may be one or more of the following: hard disk (HD), flexible disk (FD), compact disk (CD), magnetic optical disk (MO), memory card, RAM (Random Access Memory), ROM (Read Only Memory), or SSD (Solid State Drive).

[0028] In Figures 1 and 2, arrow Av indicates the vertical movement of the top plate 20; arrow Bv indicates the vertical movement of the positive electrode plate 30; arrow Ch indicates the horizontal movement of the negative electrode contact portion 40; arrow Dh indicates the horizontal movement (rotational movement) of the cleaning solution nozzle 70; and arrow Eh indicates the loading and unloading path of the wafer W.

[0029] Next, we will describe an example of the procedure for the plating process performed by the plating apparatus 1.

[0030] With the top plate 20 and positive electrode plate 30 raised and separated from the substrate holding section 12, and the negative electrode contact section 40 positioned in standby, the arm of a substrate transport mechanism (not shown) holding the wafer W enters the plating apparatus 1 and places the wafer W on the substrate holding section 12. Once the substrate holding section 12 picks up the wafer W, the arm of the substrate transport mechanism that released the wafer W exits the plating apparatus 1.

[0031] The cathode contact portion 40 moves to the processing position, and the cathode terminal 44 of the cathode contact portion 40 comes into contact with the seed layer already formed on the surface of the wafer W. The top plate 20 and the positive electrode plate 30 are also lowered to their respective predetermined processing positions.

[0032] In this state, the power supply 50 applies a voltage between the positive electrode plate 30 and the negative electrode contact portion 40, and with the voltage applied, the plating solution is discharged from the plating solution nozzle 21 (so-called hot entry method). At this time, the plating solution nozzle 21 discharges the plating solution toward the center of the positive electrode plate 30 (i.e., the center of the wafer W). As shown in Figures 7A to 7C, a portion of the plating solution that lands on the center of the positive electrode plate 30 remains in the upper region SA and spreads radially outward within the upper region SA. The remaining portion of the plating solution that lands on the center of the positive electrode plate 30 flows down through the communication passage 31 of the positive electrode plate 30 to the lower region SB and spreads radially outward within the lower region SB.

[0033] As described above, in this embodiment, (1) a plurality of communication restriction regions 32 are provided concentrically on the positive electrode plate 30, or in addition to (1) above, (2) a plurality of circular grooves 28 are formed concentrically on the lower surface of the top plate 20. Therefore, compared to the case in which at least the features of (1) and (2) above are not present, the plating solution spreads more uniformly outward in the radial direction of the wafer W in both the upper region SA and the lower region SB (details will be described later).

[0034] Once the space between the wafer W and the top plate 20 (both the upper region SA and the lower region SB) is filled with the plating solution M, the discharge of the plating solution from the plating solution nozzle 21 is stopped. The time required from the start of plating solution discharge until the space between the wafer W and the top plate 20 is filled with the plating solution is, for example, about 15 seconds. Even after the discharge of the plating solution is stopped, a voltage is continuously applied between the positive electrode plate 30 and the negative electrode contact portion 40 by the power supply device 50 until a predetermined time (plating time) has elapsed from the start of plating solution discharge, so that a current flows on the surface of the wafer W at a desired current density.

[0035] Once a predetermined plating time has elapsed, the voltage application between the positive electrode plate 30 and the negative electrode contact portion 40 is stopped. A cleaning solution, such as DIW, is also discharged from the plating solution nozzle 21 to dislodge the plating solution filling the space between the wafer W and the top plate 20 and replace it with the cleaning solution, while the components facing the space between the wafer W and the top plate 20 are cleaned with the cleaning solution.

[0036] Next, the cathode contact portion 40 is moved away from the wafer W, and the top plate 20 and the positive electrode plate 30 are raised to move them away from the wafer W.

[0037] Next, the cleaning solution nozzle 70 enters the space between the top surface of the wafer W and the positive electrode plate 30. The cleaning solution nozzle 70 is positioned, for example, directly above the center of the wafer W. In this state, the wafer W is rotated and the cleaning solution is discharged from the cleaning solution nozzle 70 onto the wafer W, cleaning the surface of the wafer W with the cleaning solution.

[0038] Next, while the wafer W continues to rotate, the discharge of the cleaning solution from the cleaning solution nozzle 70 is stopped, and the wafer W is spin-dried. When spin-drying is performed, for example, the cleaning solution nozzle 70 is retracted from above the wafer W at approximately the same time as the discharge of the cleaning solution from the cleaning solution nozzle 70 is stopped, or during the subsequent spin-drying.

[0039] Next, an arm of a substrate transport mechanism (not shown) enters the plating apparatus 1, removes the wafer W from the substrate holding section 12, and transports it outside the plating apparatus 1. This completes the series of procedures performed within the plating apparatus 1 for one wafer W.

[0040] Next, the effects of this embodiment will be described.

[0041] First, as a comparative example, we will describe the behavior of the plating solution after it is discharged from the plating solution nozzle 21 in the case where there is no communication restriction area 32 (where through holes (communication passages) are provided almost uniformly across almost the entire surface of the positive electrode plate 30).

[0042] Without the communication restriction region 32, the plating solution discharged from the plating solution nozzle 21 flows relatively freely from the upper region SA to the lower region SB through the through-hole (communication passage 31) of the positive electrode plate 30 at a flow rate corresponding to the opening ratio (of the through-hole). The plating solution that falls into the lower region SB spreads outwards in the radial direction of the wafer W. On the other hand, even in the upper region SA, the plating solution also tries to spread outwards in the radial direction of the wafer W, but at that time the plating solution also falls from the upper region SA to the lower region SB. As a result, the radial outward spread of the plating solution in the lower region SB is considerably faster than in the upper region SA, and the distribution of the radial outward spread velocity of the plating solution in the circumferential direction of the wafer W is varied. Such behavior of the plating solution is schematically shown in Figures 6A and 6B.

[0043] If, in a portion of the positive electrode plate 30, the area below the positive electrode plate 30 is filled with the plating solution, while the area above the positive electrode plate 30 is not, the current density of the plating current becomes unstable in the vicinity of that portion. Therefore, especially in the case of hot entry processing, the in-plane uniformity of the plating film thickness may deteriorate.

[0044] On the other hand, when the communication restriction region 32 is provided as in the present embodiment, as shown in FIGS. 7A, 7B, and 7C, the amount of the plating solution flowing down from the upper region SA to the lower region SB decreases, so that the speed at which the plating solution spreads radially outward in the lower region SB decreases. Also, the amount of the plating solution remaining in the upper region SA increases by the amount by which the amount of the plating solution flowing down to the lower region SB decreases, and the speed at which the plating solution spreads radially outward in the upper region SA increases. That is, the speed at which the plating solution spreads radially outward in the upper region SA and the lower region SB becomes uniform. By this alone, the current density of the plating current is stabilized, and the in-plane uniformity of the plating film thickness can be enhanced (mechanism 1).

[0045] Also, when the communication restriction region 32 is a region without through holes, the lower surface of the positive electrode plate 30 in the communication restriction region 32 becomes flat. When the plating solution tries to move while contacting the flat surface, the plating solution receives a relatively large frictional force from the flat surface (for this reason, pressure loss occurs). For this reason, the speed at which the plating solution spreads radially outward in the lower region SB decreases. Also by this, the speed at which the plating solution spreads radially outward in the lower region SB decreases and becomes close to the speed at which the plating solution spreads radially outward in the upper region SA. Also by this, the current density of the plating current is stabilized, and the in-plane uniformity of the plating film thickness can be enhanced (mechanism 2).

[0046] In addition, when a large number of small holes are provided on the surface like the non-restriction region 33, the liquid tends to spread more easily compared to a flat surface. From this viewpoint, it can also be said that the plating solution tends to be difficult to spread radially outward at the communication restriction region 32.

[0047] Also, at the communication restriction region 32, since the speed at which the plating solution spreads radially outward is restricted, the plating solution tends to spread more easily in the circumferential direction by that amount. For this reason, the plating solution tends to spread uniformly in the radial direction and the circumferential direction. Also by this, the current density of the plating current is stabilized, and the in-plane uniformity of the plating film thickness can be enhanced (mechanism 3).

[0048] When the communication restriction region 32 is a region without through holes, the upper surface of the positive electrode plate 30 in the communication restriction region 32 also becomes flat. In this case, the rate at which the plating solution spreads radially outward also decreases in the upper region SA. However, since the rate at which the plating solution spreads radially outward is restricted, the plating solution is more likely to spread circumferentially in the upper region SA by that much. Therefore, the plating solution is likely to spread uniformly in the radial and circumferential directions. This also stabilizes the current density of the plating current and improves the in-plane uniformity of the plating film thickness (mechanism 4).

[0049] In addition, the effects according to the above-described mechanisms 1 to 4 can also be obtained when the communication restriction region 32 is a region where the aperture ratio (of the through holes) is smaller than that of the non-restriction region 33 (although the effect is smaller compared to the case where the communication restriction region 32 is a region without through holes).

[0050] Also, in the present embodiment, as described above, a plurality of ring-shaped grooves 28 are formed concentrically on the lower surface of the top plate 20. Therefore, the frictional force acting between the plating solution flowing in the upper region SA and the top plate 20 becomes smaller compared to the case where the entire lower surface of the top plate 20 is flat. For this reason, the rate at which the plating solution spreads radially outward in the upper region SA becomes higher compared to the case where the entire lower surface of the top plate 20 is flat. Further, the plating solution is guided circumferentially in the groove 28 and spreads circumferentially, and after substantially the entire one groove 28 is filled with the plating solution, it spreads toward the outer groove. Therefore, in the upper region SA, the plating solution is likely to spread uniformly in the radial and circumferential directions. From this as well, the current density of the plating current is stabilized and the in-plane uniformity of the plating film thickness can be improved.

[0051] When forming multiple circular grooves 28 concentrically on the lower surface of the top plate 20, it is preferable that the pitch of the grooves 28 be uniform from the center to the periphery of the top plate 20, or that it decrease as it approaches the periphery. If the pitch of the grooves 28 is increased, the width of the top surface of the protrusion between adjacent grooves 28 (which is usually a flat surface) increases, and the frictional force acting between the top surface and the plating solution increases. At the periphery of the lower surface of the top plate 20, the volume per unit radius length of the upper region SA is large, so increasing the pitch of the grooves 28 is undesirable because it becomes difficult to fill with the plating solution.

[0052] Furthermore, the upper surface of the wafer W, which forms the bottom surface of the lower region SB, can also be considered substantially flat (i.e., with high friction) (although there are some irregularities due to the device formation process). For this reason, even if the upper and lower surfaces of the positive electrode plate 30 are formed similarly, the friction experienced by the plating solution flowing through the upper region SA tends to be less than the friction experienced by the plating solution flowing through the lower region SB. From this viewpoint as well, the configuration of forming multiple circular grooves 28 concentrically on the lower surface of the top plate 20 is beneficial.

[0053] <Second Embodiment> Next, a second embodiment of the plating apparatus will be described. The second embodiment differs from the first embodiment only in the configuration of the anode plate 30. As shown in Figure 8, the anode plate 30 used in the second embodiment has a configuration in which through holes (communication passages 31) are uniformly provided over substantially its entire surface (a configuration similar to a punching plate), and a communication restriction area 32A is provided by attaching a plurality of ring-shaped sheet-like sealing members 34 concentrically to the lower surface of the anode top plate 30. In one example configuration, a sealing member 34 made of a plate-shaped or sheet-like material (such as tape) whose surface is hydrophilic or has been made hydrophilic may be attached to the lower surface of the anode top plate 30.

[0054] In other words, in this second embodiment, the sealing member 34 in the communication restriction region 32A closes the lower end opening of the through hole (communication passage 31) of the positive electrode plate 30, thereby restricting the flow of the plating solution from the upper region SA to the lower region SB in the communication restriction region 32A to zero. As a result, the amount of plating solution flowing down from the upper region SA to the lower region SB is reduced, and the effect based on the mechanism 1 described above is obtained.

[0055] Furthermore, since the surface of the sealing member 34 is flat, the effects based on the mechanisms 2 and 3 described above can be obtained. Specifically, the rate at which the plating solution spreads radially outward in the lower region SB decreases, and the plating solution spreads more uniformly in both the radial and circumferential directions. This also stabilizes the current density of the plating current and improves the in-plane uniformity of the plating film thickness.

[0056] Furthermore, in this second embodiment, the upper end opening of the through hole in the positive electrode plate 30 is open across the entire surface of the positive electrode plate 30. As a result, the upper surface of the positive electrode plate 30 has a structure in which numerous recesses are regularly arranged throughout. As described earlier in the description of the first embodiment, the plating solution spreads more easily on a surface with such a structure compared to a flat surface. As a result, the rate at which the plating solution spreads radially outward in the upper region SA becomes close to the rate at which the plating solution spreads radially outward in the lower region SB. This also stabilizes the current density of the plating current and improves the in-plane uniformity of the plating film thickness.

[0057] In the second embodiment, unlike the first embodiment, the entire upper surface of the positive electrode plate 30 has uniform irregularities. Therefore, using a top plate having a plurality of concentric circular grooves 28 on its lower surface, similar to the first embodiment, is beneficial for obtaining a more uniform spread of the plating solution in the radial and circumferential directions within the upper region SA.

[0058] <Third Embodiment> The third embodiment differs from the first embodiment only in the configuration of the positive electrode plate 30. In the third embodiment, as shown in Figure 9, the positive electrode plate 30 has two sheets 35a and 35b and a plurality of thin, circular sheet-like shielding members 36 arranged concentrically and sandwiched between the two sheets 35a and 35b. Each sheet 35a and 35b has a configuration in which through holes are provided almost uniformly over substantially its entire surface (a configuration similar to a punching plate).

[0059] A through-hole 31a formed in the upper sheet 35a and a through-hole 31b formed in the lower sheet 35b are connected, forming a communication passage 31 in the positive electrode plate 30. The sheet-shaped blocking member 36 blocks communication between the through-hole 31a and the through-hole 31b. As a result, the area where the blocking member 36 is provided becomes a communication restriction area 32 (Configuration Example 1). In the communication restriction area 32, the flow of the plating solution from the upper area SA to the lower area SB is restricted to zero. Therefore, the amount of plating solution flowing from the upper area SA to the lower area SB is reduced, and the effect based on the mechanism 1 described above is obtained.

[0060] The positive electrode plate 30 shown in Figure 9 may be manufactured by joining sheets 35a, 35b and a sheet-like shielding member 36, and then applying an iridium oxide coating. The sheets 35a, 35b and the shielding member 36 can be joined, for example, by bonding the entire surfaces of the opposing surfaces together. Alternatively, only a portion of the opposing surfaces may be joined by spot welding.

[0061] As shown in Figure 10, the size (hole diameter) of the through-hole 31a formed in the upper sheet 35a and the through-hole 31b formed in the lower sheet 35b may be different. Specifically, for example, the arrangement positions of the through-holes 31a and 31b (the planar arrangement positions of the centers of each through-hole) may be the same, and only the hole diameters of the through-holes 31a and 31b may be different (Configuration Example 2). In this Configuration Example 2, by appropriately adjusting the opening ratio (hole diameter and arrangement of the through-holes) on the upper and lower surfaces of the positive electrode plate 30, the ease with which the plating solution spreads can be changed between the upper and lower surfaces. As a result, it becomes possible to spread the plating solution radially outward at the same speed from the upper region SA to the lower region SB. Furthermore, by changing the hole diameter of the through-holes 31a and / or through-holes 31b depending on the location, the flow rate of the plating solution falling from the upper region SA to the lower region SB can be controlled to a suitable value for each location.

[0062] The arrangement pattern (position) of the through holes 31a formed in the upper sheet 35a and the through holes 31b formed in the lower sheet 35b may be different (Configuration Example 3). Specifically, for example, as shown in Figure 11, a ring-shaped region may be set in the lower sheet 35b without through holes 31b. In this case, the region corresponding to the ring-shaped region becomes the communication restriction region 32. Alternatively, instead of not providing through holes 31b throughout the entire ring-shaped region, the opening ratio of the through holes 31b in the ring-shaped region may be reduced (for example, the number of through holes 31b per unit area may be half that of other regions).

[0063] The above-mentioned configuration examples (configuration examples 1 to 3, etc.) may be used in combination as appropriate.

[0064] Furthermore, multiple non-conflicting embodiments from the above-described embodiments may be used in combination.

[0065] <Fourth Embodiment> The fourth embodiment relates to a procedure for supplying a plating solution while raising and lowering the positive electrode plate 30, using the configuration of the first embodiment (or the second and third embodiments). First, as shown in Figure 12A, the positive electrode plate 30 is lowered to widen the vertical width of the upper region SA (narrowing the lower region SB), and the supply of the plating solution from the plating solution nozzle 21 is started. At this time, the flow resistance of the plating solution increases in the lower region SB, which has a narrow vertical width, making it difficult for the plating solution to spread radially outward. On the other hand, in the upper region SA, which has a wide vertical width, the plating solution spreads radially outward easily.

[0066] After the plating solution has spread to some extent in the upper region SA, the positive electrode plate 30 is lowered to narrow the vertical width of the upper region SA (widening the lower region SB), as shown in Figure 12B. As a result, a portion of the plating solution in the upper region SA is pushed radially outward, and another portion is pushed into the lower region SB through the through-hole (communication passage 31). In addition, in the lower region SB, which has widened vertically, the plating solution spreads more easily radially outward. According to this fourth embodiment, by appropriately setting the timing for raising the positive electrode plate 30, the spread of the plating solution in the upper region SA and the lower region SB can be made uniform.

[0067] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The above embodiments may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims.

[0068] The substrates to be plated are not limited to semiconductor wafers, but may also be various other substrates used in the field of semiconductor equipment manufacturing, such as glass substrates and ceramic substrates.

[0069] 12 Substrate holding section 20 Top plate 21 Plating solution discharge port (plating solution nozzle) 22 Plating solution supply section 30 Positive electrode plate 31 Communication passage 32 Communication restricted area 33 Area other than the communication restricted area (unrestricted area) 40 Cathode (cathode electrode terminal 44) 50 Power supply unit SA Upper area SB Lower area

Claims

1. The device comprises: a substrate holding portion for holding a substrate; a cathode that can contact the substrate held by the substrate holding portion; a top plate that covers the substrate held by the substrate holding portion from above; a plating solution nozzle provided on the top plate for discharging a plating solution into the space between the substrate and the top plate toward the center of the substrate held by the substrate holding portion; a positive electrode plate positioned in the plating solution filling the space and covering the substrate held by the substrate holding portion from above, the positive electrode plate dividing the space into an upper region above the positive electrode plate and a lower region below the positive electrode plate; and a power supply device that applies a voltage between the cathode and the positive electrode plate and causes a plating current to flow between the substrate in contact with the cathode and the positive electrode plate, wherein the positive electrode plate has a number of connecting passages that penetrate the positive electrode plate, and the plating solution can flow from the upper region to the lower region through the connecting passages. A plating apparatus in which the positive electrode plate has a plurality of communication restriction regions arranged concentrically, and in the communication restriction regions, the flow of the plating solution from the upper region to the lower region is restricted compared to regions other than the communication restriction regions.

2. The plating apparatus according to claim 1, wherein the positive electrode plate has a number of through holes that penetrate the positive electrode plate in the thickness direction from the upper surface to the lower surface of the positive electrode plate as the number of communication passages, and the communication restriction region is a region in which no through holes are formed.

3. The plating apparatus according to claim 1, wherein the positive electrode plate has a number of through holes that penetrate the positive electrode plate in the thickness direction from the upper surface to the lower surface of the positive electrode plate, and the communication restriction region is a region in which the opening ratio of the through holes is smaller than that of the region other than the communication restriction region.

4. The plating apparatus according to claim 1, wherein the positive electrode plate has a number of through holes that penetrate the positive electrode plate in the thickness direction from the upper surface to the lower surface of the positive electrode plate, and the communication restriction region is a region in which the lower end of the through holes is closed by a sealing member.

5. The plating apparatus according to claim 4, wherein the sealing member is provided such that the lower surface of the positive electrode plate in the communication restriction region becomes flat.

6. The plating apparatus according to claim 1, wherein the positive electrode plate is formed by bonding together an upper portion and a lower portion of a sheet.

7. The plating apparatus according to claim 6, wherein the upper and lower sheet portions each have a number of through holes that penetrate them in the thickness direction, and the number of communication passages is formed by at least some of the through holes in the upper and lower portions communicating with each other.

8. The plating apparatus according to claim 7, wherein a blocking member is concentrically arranged between the upper portion and the lower portion to block communication between the through-hole of the upper portion and the through-hole of the lower portion, and the region in which the blocking member is provided becomes the communication restriction region.

9. The plating apparatus according to claim 7, wherein the lower portion is provided with a plurality of concentric regions in which the through holes are not provided, and these plurality of regions constitute the plurality of communication restriction regions.

10. The plating apparatus according to claim 7, wherein the arrangement pattern of the through holes in the upper portion is different from the arrangement pattern of the through holes in the lower portion.

11. The plating apparatus according to claim 7, wherein the diameter of the through hole in the upper portion is different from the diameter of the through hole in the lower portion.

12. The plating apparatus according to claim 1, wherein the radial width of the communication restriction area is smaller than the radial width of the area other than the communication restriction area.

13. The plating apparatus according to claim 1, wherein a plurality of concentric recesses are formed on the underside of the top plate.

14. The plating apparatus according to claim 13, wherein the number of recesses per unit radial length of the top plate is uniform regardless of radial position.

15. The plating apparatus according to claim 13, wherein the number of recesses per unit radial length of the top plate increases as the radius outward.

16. The device comprises: a substrate holding portion for holding a substrate; a cathode that can contact the substrate held by the substrate holding portion; a top plate that covers the substrate held by the substrate holding portion from above; a plating solution nozzle provided on the top plate for discharging a plating solution into the space between the substrate and the top plate toward the center of the substrate held by the substrate holding portion; a positive electrode plate positioned in the plating solution filling the space and covering the substrate held by the substrate holding portion from above, the positive electrode plate dividing the space into an upper region above the positive electrode plate and a lower region below the positive electrode plate; and a power supply device that applies a voltage between the cathode and the positive electrode plate and causes a plating current to flow between the substrate in contact with the cathode and the positive electrode plate, wherein the positive electrode plate has a number of connecting passages that penetrate the positive electrode plate, and the plating solution can flow from the upper region to the lower region through the connecting passages. A plating method using a plating apparatus, wherein the positive electrode plate has a plurality of communication restriction regions arranged concentrically, and in the communication restriction regions, the flow of the plating solution from the upper region to the lower region is restricted compared to regions other than the communication restriction regions, the method comprising: holding the substrate with the substrate holding part; positioning the positive electrode plate at a predetermined height above the substrate; discharging the plating solution from the plating solution nozzle on the top plate toward the center of the positive electrode plate while applying a voltage between the cathode and the positive electrode plate; and filling the upper region and the lower region with the plating solution while restricting the inflow of the plating solution from the upper region to the lower region by the communication restriction regions of the positive electrode plate, and restricting the radial outward spread of the plating solution in at least the lower region.

17. The plating method according to claim 16, wherein when discharging a plating solution from the plating solution nozzle of the top plate toward the center of the positive electrode plate, the discharging of the plating solution from the plating solution nozzle is started with the vertical distance between the upper surface of the positive electrode plate and the lower surface of the top plate adjusted to a first distance, and then the discharging of the plating solution from the plating solution nozzle is continued with the vertical distance adjusted to a second distance smaller than the first distance.

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