Plating apparatus

Abstract

Provided is a plating apparatus. This plating apparatus is provided with: a substrate holder which is configured to be rotatable around a first rotation axis during plating; an anode; a resistor for electric field adjustment, the resistor having a plurality of through holes which are in communication with the anode side and the substrate holder side of the resistor; and at least one rotatable member for electric field adjustment, which is disposed between the anode and the resistor. Each of the at least one rotatable member is configured to be rotatable around a second rotation axis that extends in a direction that intersects with the first rotation axis. Each of the at least one rotatable member is configured to be rotatable between a first position at which the at least one rotatable member overlaps a part of the plurality of through holes of the resistor when viewed from the direction in which the first rotation axis extends, and a second position at which the overlap between each of the rotatable members and the plurality of through holes is smaller than that at the first position when viewed from the direction in which the first rotation axis extends.

Description

Plating Equipment

[0001] The present application relates to a plating apparatus.

[0002] One example of a plating apparatus using electroplating is a so-called dip-type plating apparatus in which a substrate (e.g., a semiconductor wafer) and an anode are arranged horizontally facing each other (see, for example, Patent Document 1). Another example of a plating apparatus using electroplating is a cup-type plating apparatus (see, for example, Patent Document 2). In the cup-type plating apparatus, a substrate held by a substrate holder is immersed in a plating solution with the surface to be plated facing downward, and a voltage is applied between the substrate and the anode to deposit a conductive film (plating film) on the surface of the substrate.

[0003] In such plating apparatuses, the substrate generally has an electrical contact on its periphery. Due to differences in distance from the electrical contact, a potential difference occurs between the periphery and center of the substrate during plating, which can result in a bias in the plating current. For this reason, it has been known to place a resistor for adjusting the electric field between the substrate and the anode to improve the uniformity of the thickness of the plating film formed on the substrate. Furthermore, a plating apparatus has been proposed in which the size of the resistor hole is variable to allow for greater freedom in adjusting the electric field (see Patent Document 3).

[0004] Patent No. 7462125 Patent No. 7079388 Patent No. 7204060

[0005] In plating equipment, uneven plating film thickness can occur due to factors other than the distance from the electrical contacts, such as the resist pattern formed on the substrate. In other words, if the substrate surface to be plated contains a certain number of areas without resist openings (non-opening areas), the plating current does not flow through the non-opening areas, and instead concentrates around the non-opening areas, resulting in a thicker plating film. As a specific example, if resist openings are formed only in a roughly cross-shaped area on the substrate, the area outside the cross does not have resist openings and current does not flow, potentially resulting in a loss of uniformity in the thickness of the plating film. For example, Patent Document 1 uses an anode mask with adjustable anode opening dimensions to adjust the electric field between the anode and the substrate. However, conventional configurations are designed to address variations in plating film thickness due to the configuration of the plating equipment, such as electrical contacts, and may not adequately address variations in plating film thickness due to the resist pattern on the substrate. While forming dummy openings in the non-opening areas to achieve uniform plating film thickness is conceivable, this increases plating process costs due to the additional processing required to form the dummy openings and the formation of unnecessary plating in the dummy openings.

[0006] The present invention has been made in view of the above problems, and one of its objects is to propose a plating apparatus that can improve the uniformity of the thickness of a plating film formed on an object to be plated.

[0007] According to one aspect of the present invention, there is provided a plating apparatus comprising: a plating tank; a substrate holder configured to hold a substrate and to be rotatable about a first rotation axis during plating; an anode disposed in the plating tank facing the substrate held by the substrate holder; a resistor for adjusting an electric field disposed between the anode and the substrate holder, the resistor having a plurality of through holes communicating with the anode side and the substrate holder side of the resistor; and at least one rotatable member for adjusting the electric field disposed between the anode and the resistor, each of the at least one rotatable member being rotatable about a second rotation axis extending in a direction intersecting the first rotation axis, and each of the at least one rotatable member being rotatable between a first position where the rotatable member overlaps a portion of the through holes in the resistor and a second position where the overlap between the rotatable member and the through holes is smaller than that at the first position, as viewed in the direction of extension of the first rotation axis.

[0008] FIG. 1 is a perspective view showing the overall configuration of a plating apparatus according to this embodiment. FIG. 2 is a plan view showing the overall configuration of the plating apparatus according to this embodiment. FIG. 3 is a longitudinal cross-sectional view schematically showing the configuration of a plating module according to this embodiment. FIG. 4 is an enlarged bottom view schematically showing the surface of a resistor closest to the anode according to this embodiment. FIG. 5 is a conceptual diagram showing the rotation of multiple rotatable members. FIG. 6 is a conceptual diagram showing rotatable members and an electric field arranged diagonally with respect to the rotation axis of a substrate holder. FIG. 7 is a conceptual diagram showing rotatable members and an electric field arranged along the rotation axis of a substrate holder. FIG. 8 is a schematic bottom view showing rotatable members arranged perpendicular to the rotation axis of a substrate holder and a drive mechanism. FIG. 9 is a schematic bottom view showing rotatable members arranged perpendicular to the rotation axis of a substrate holder and a through-hole in a resistor. FIG. 10 is a schematic bottom view of a rotatable member arranged diagonally with respect to the rotation axis of a substrate holder. FIG. 11 is a schematic bottom view showing rotatable members arranged along the rotation axis of a substrate holder and a through-hole in a resistor. Fig. 12 is a flowchart showing an example of a method for setting an operation recipe for the rotatable member, anode mask, and shield by the control module. Fig. 13 is a diagram schematically showing a resist pattern formed on a surface to be plated of a substrate in one embodiment. Fig. 14 is a flowchart showing an example of a method for setting an operation recipe for the rotatable member, anode mask, and shield by the control module during plating processing. Fig. 15 is a schematic bottom view showing a rotatable member of a modified example.

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings described below, identical or corresponding components are designated by the same reference numerals, and redundant description will be omitted.

[0010] <Overall Configuration of Plating Apparatus> Fig. 1 is a perspective view showing the overall configuration of a plating apparatus 1000 according to this embodiment. Fig. 2 is a plan view showing the overall configuration of the plating apparatus 1000. As shown in Figs. 1 and 2, the plating apparatus 1000 includes a load port 100, a transfer 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 transfer device 700, and a control module 800.

[0011] The load port 100 is a module for loading substrates, which are objects to be plated and are stored in cassettes such as FOUPs (not shown), into the plating apparatus 1000, and for unloading substrates from the plating apparatus 1000 to the cassettes. In this embodiment, four load ports 100 are arranged horizontally, but the number and arrangement of the load ports 100 are optional. The transfer robot 110 is a robot for transporting substrates, and is configured to transfer substrates between the load ports 100, the aligner 120, and the transfer device 700. When transferring substrates between the transfer robot 110 and the transfer device 700, the transfer robot 110 and the transfer device 700 can transfer the substrates via a temporary stage (not shown).

[0012] The aligner 120 is a module for aligning the positions of the substrate's orientation flat, notch, and the like in a predetermined direction. In this embodiment, two aligners 120 are arranged horizontally, but the number and arrangement of the aligners 120 are optional. The prewet module 200 wets the surface of the substrate to be plated with a treatment liquid (prewet liquid) such as pure water or degassed water before plating, thereby replacing air inside the pattern formed on the substrate surface with the treatment liquid. The prewet module 200 is configured to perform a prewet process during plating, replacing the treatment liquid inside the pattern with a plating liquid to facilitate the supply of plating liquid inside the pattern. In this embodiment, two prewet modules 200 are arranged vertically, but the number and arrangement of the prewet modules 200 are optional.

[0013] The presoak module 300 is configured to perform a presoak process, which involves etching away, for example, 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 to clean or activate the surface of the substrate to be plated. In this embodiment, two presoak modules 300 are arranged vertically, but the number and arrangement of the presoak modules 300 are optional. The plating module 400 performs plating on the substrate. In this embodiment, two sets of 12 plating modules 400 are arranged vertically, three vertically and four horizontally, for a total of 24 plating modules 400, but the number and arrangement of the plating modules 400 are optional.

[0014] The cleaning module 500 is configured to perform a cleaning process on the substrate to remove plating solution and the like remaining on the substrate after plating. In this embodiment, two cleaning modules 500 are arranged vertically, but the number and arrangement of the cleaning modules 500 are optional. The spin rinse dryer 600 is a module for drying the substrate after cleaning by rotating it at high speed. In this embodiment, two spin rinse dryers are arranged vertically, but the number and arrangement of the spin rinse dryers are optional. The transport device 700 is a device for transporting substrates between multiple modules within the plating apparatus 1000. The control module 800 is configured to control the multiple modules of the plating apparatus 1000 and can be configured, for example, as a general computer or a dedicated computer equipped with an input / output interface with an operator.

[0015] An example of a series of plating processes performed by the plating apparatus 1000 will be described. First, a substrate stored in a cassette is loaded into the load port 100. Next, the transfer robot 110 removes the substrate from the cassette in the load port 100 and transfers the substrate to the aligner 120. The aligner 120 aligns the positions of the orientation flat, notch, etc. of the substrate to a predetermined direction. The transfer robot 110 delivers the substrate, whose direction has been aligned by the aligner 120, to the transfer apparatus 700.

[0016] The transfer device 700 transfers the substrate received from the transfer robot 110 to the prewet module 200. The prewet module 200 performs a prewet process on the substrate. The transfer device 700 transfers the substrate that has been subjected to the prewet process to the presoak module 300. The presoak module 300 performs a presoak process on the substrate. The transfer device 700 transfers the substrate that has been subjected to the presoak process to the plating module 400. The plating module 400 performs a plating process on the substrate.

[0017] The transfer device 700 transfers the substrate that has been plated to the cleaning module 500. The cleaning module 500 performs a cleaning process on the substrate. The transfer device 700 transfers the substrate that has been cleaned to the spin rinse dryer 600. The spin rinse dryer 600 dries the substrate. The transfer device 700 delivers the substrate that has been dried to the transfer robot 110. The transfer robot 110 transfers the substrate received from the transfer device 700 to a cassette on the load port 100. Finally, the cassette containing the substrate is removed from the load port 100.

[0018] <Configuration of Plating Module> Next, the configuration of the plating module 400 will be described. Since the 24 plating modules 400 in this embodiment have the same configuration, only one plating module 400 will be described. FIG. 3 is a longitudinal cross-sectional view schematically showing the configuration of the plating module 400 of this embodiment. As shown in FIG. 3, the plating module 400 includes a plating tank 410 for containing a plating solution. The plating tank 410 includes a cylindrical inner tank 412 with an open top, and an outer tank 414 provided around the inner tank 412 so as to collect plating solution that overflows from the upper edge of the inner tank 412.

[0019] The plating module 400 includes a substrate holder 440 for holding the substrate Wf with its plating surface Wf-a facing downward. The substrate holder 440 also includes a power supply contact for supplying power to the substrate Wf from a power source (not shown). The plating module 400 also includes a lifting mechanism 442 for raising and lowering the substrate holder 440. The plating module 400 also includes a rotation mechanism 448 for rotating the substrate holder 440 around a first rotation axis Ax1 during plating. In this embodiment, the first rotation axis Ax1 preferably extends vertically. The first rotation axis Ax1 may coincide with the central axis of the inner tank 412, which extends vertically. The lifting mechanism 442 and the rotation mechanism 448 can be realized by known mechanisms, such as motors.

[0020] The plating apparatus 1000 is a cup-type electrolytic plating apparatus that immerses a substrate Wf (e.g., a semiconductor wafer) held by a substrate holder 440 in a plating solution with its surface Wf-a to be plated facing downward, and deposits a conductive film on the surface of the substrate Wf by applying a voltage between the substrate Wf and an anode 430. By performing the plating process while rotating the substrate Wf about the first rotation axis Ax1, the thickness of the plating formed on the substrate Wf becomes more uniform.

[0021] The plating module 400 includes a membrane 420 that vertically separates the interior of the inner tank 412. The interior of the inner tank 412 is divided by the membrane 420 into a cathode region 422 and an anode region 424. The cathode region 422 and the anode region 424 are each filled with a plating solution. Note that, although an example in which the membrane 420 is provided has been shown in this embodiment, the membrane 420 need not be provided.

[0022] An anode 430 is provided on the bottom surface of the inner tank 412 in the anode region 424. The anode 430 is disposed in the plating tank 410 so as to face the substrate Wf held by the substrate holder 440. An anode mask 426 for adjusting the electrolysis between the anode 430 and the substrate Wf is also disposed in the anode region 424. The anode mask 426 is, for example, a substantially plate-shaped member made of a dielectric material, and is provided in front of (above) the anode 430. The anode mask 426 has an anode opening 427, which is an opening through which a current flows between the anode 430 and the substrate Wf. While the present embodiment illustrates an example in which the anode mask 426 is provided, the anode mask 426 need not be provided. Furthermore, the above-described membrane 420 may be provided in the anode opening 427.

[0023] In the cathode region 422, a resistor 450 is disposed between the anode 430 and the substrate holder 440. In this embodiment, the resistor 450 faces the membrane 420. The resistor 450 is a member for adjusting the electric field in the plating solution and for achieving uniformity in the plating process on the plating surface Wf-a of the substrate Wf. In the illustrated example, the resistor 450 is cylindrical and is disposed so that the axial direction of the cylinder substantially coincides with the first rotation axis Ax1. The shape of the resistor 450 is not particularly limited as long as plating can be performed with the desired accuracy.

[0024] The resistor 450 is formed of a material having a higher electrical resistivity than the plating solution. This material is preferably a dielectric material. The resistor 450 may contain metal or resin. The electric field adjusting resistor 450 has a first surface 451 on the anode side and a second surface 452 on the substrate holder side.

[0025] 4 is an enlarged bottom view schematically illustrating the first surface 451 of the resistor 450 on the anode side. The resistor 450 has a plurality of through-holes 453 formed therein. The through-holes 453 penetrate between the first surface 451 and the second surface 452 of the resistor 450, forming a path through which the plating solution and the ions in the plating solution pass. In other words, the resistor 450 connects, via the through-holes 453, the cathode region 422 on the anode side of the resistor 450 to the cathode region 422 on the substrate holder side of the resistor 450, allowing the plating solution and the ions in the plating solution to move. Each of the plurality of through-holes 453 communicates with the anode side and the substrate holder side of the resistor 450. In the example of Figure 4, the through holes 453 are arranged regularly so that the distance between adjacent through holes 453 is constant, but the pattern of the through holes 453 is not particularly limited as long as plating can be performed with the desired precision, and the through holes 453 may be arranged randomly.

[0026] The resistor 450 may have a porous structure with a plurality of through holes 453. With such a configuration, the holes are arranged in a dispersed manner, and by adjusting the current passing through these holes, the thickness of the plating formed on the substrate Wf can be made uniform.

[0027] As shown in FIG. 3, the plating module 400 includes at least one rotatable member 470. In this embodiment, the plating module 400 has multiple rotatable members 470. The rotatable members 470 are resistive members that adjust the electric field in the plating solution and ensure uniformity in the plating process on the plating surface Wf-a of the substrate Wf. The rotatable member 470 for adjusting the electric field is formed of a member having a higher electrical resistivity than the plating solution. This member is preferably a dielectric. The rotatable member 470 may include a metal or a resin.

[0028] The rotatable member 470 is disposed between the anode 430 and the resistor 450. The rotatable member 470 may be disposed between the anode 430 and the resistor 450 in the direction in which the first rotation axis Ax1 extends. In the cup-type plating module 400 according to this embodiment, the rotatable member 470 may be disposed between the anode 430 and the resistor 450 in the vertical direction. The rotatable member 470 is preferably disposed between the anode mask 426 and the resistor 450. Furthermore, as shown in the illustrated example, the rotatable member 470 may be disposed between the membrane 420 and the resistor 450.

[0029] FIG. 5 is a conceptual diagram illustrating the rotation of the rotatable members 470. FIG. 5 illustrates only the rotatable members 470 viewed from a direction perpendicular to the first rotation axis Ax1. In FIG. 5, the rotation of the rotatable members 470 is schematically indicated by the arrow Ar1. In the illustrated example, seven rotatable members 470 are shown, but the number of rotatable members 470 arranged in the plating module 400 is not particularly limited and may be one to six or eight or more. Each rotatable member 470 includes a plate-shaped main body 471 and a shaft 472 extending from the main body 471. The plate-shaped main body 471 can increase the change in the electric field caused by the rotation of the rotatable member 470. The shaft 472 extends in a direction perpendicular to the first rotation axis Ax1. In the illustrated example, the leftmost and rightmost rotatable members 470 have a smaller width along the plate-shaped main body 471, perpendicular to the long axis of the shaft 472, than the other rotatable members 470. However, the dimensions of each rotatable member 470 are not particularly limited, and can be set appropriately depending on the position where the electric field is desired to be changed during plating.

[0030] Each rotatable member 470 has a second rotation axis Ax2 and is configured to be rotatable about the second rotation axis Ax2. The second rotation axis Ax2 preferably coincides with the longitudinal axis of the shaft 472. The second rotation axis Ax2 extends in a direction intersecting the first rotation axis Ax1. Although the second rotation axis Ax2 can achieve the effect of adjusting the electric field even if it is not perpendicular to the first rotation axis Ax1, the second rotation axis Ax2 is preferably approximately perpendicular to the first rotation axis Ax1. This configuration can increase the change in the area of ​​the rotatable member 470 projected onto a plane perpendicular to the direction from the anode 430 toward the substrate Wf during plating, thereby further increasing the change in the electric field due to the rotation of the rotatable member 470. This can result in a greater change in the plating current and improved thickness uniformity of the plating film formed on the object to be plated. Hereinafter, the angle between the plane perpendicular to the first rotation axis Ax1 and the extension direction of the plate-shaped main body 471 is referred to as the rotation angle θ.

[0031] Fig. 6 is a conceptual diagram showing a rotatable member 470 in which a plate-shaped main body 471 is disposed obliquely with respect to the first rotation axis Ax1 due to rotation. Fig. 7 is a conceptual diagram showing a rotatable member 470 in which the plate-shaped main body 471 is disposed so as to extend parallel to the first rotation axis Ax1. In Figs. 6 and 7, the electric field is schematically indicated by arrow Ar2, a schematic vertical cross section of the inner tank 412 is shown, and the rotatable member 470 is schematically shown as viewed from the direction in which the second rotation axis Ax2 extends.

[0032] 6 , the plate-shaped main body 471 extends in a direction intersecting the direction of the electric field directed from the anode 430 to the substrate holder 440 above, so that the electric field lines corresponding to the electric field go around the plate-shaped main body 471. In this case, the density of the electric field lines above the rotatable member 470 is smaller than when the electric field travels straight. In other words, the electric resistance of the rotatable member 470 increases with respect to the current passing through the through-hole 453 above the rotatable member 470. This weakening of the electric field due to the resistance of the rotatable member 470 is called electric field shielding by the rotatable member 470.

[0033] 7, the direction of the electric field is parallel to the extension direction of the plate-like main body 471, so that the electric field does not deviate much and the effect of the rotatable member 470 on the electric field is small. Therefore, the local change in plating current due to the rotatable member 470 is small.

[0034] The rotatable member 470 exhibits the greatest resistance during plating when the plate-shaped main body 471 extends perpendicular to the first rotation axis Ax1, i.e., when the rotation angle θ is 0°. As the rotation angle θ of the plate-shaped main body 471 increases from 0° to 90°, the resistance during plating by the rotatable member 470 decreases. The rotatable member 470 exhibits the smallest resistance during plating when the plate-shaped main body 471 extends parallel to the first rotation axis Ax1, i.e., when the rotation angle θ is 90°. In this manner, the magnitude of the local plating current can be controlled by rotating the rotatable member 470. In the illustrated example, the second rotation axes Ax2 of the rotatable members 470 are parallel to each other, but this is not a limitation.

[0035] 8 is a schematic bottom view showing the rotatable members 470 as viewed from the anode side along the direction of extension of the first rotation axis Ax1. In the illustrated example, the rotation angle θ of each rotatable member 470 is 0°, and at this time, the plate-shaped bodies 471 of the multiple rotatable members 470 integrally form a single plate-shaped shielding member 47. In this manner, when each of the multiple rotatable members 470 is in a predetermined rotational position, it is preferable that the multiple rotatable members 470 integrally form a plate-shaped shielding member 47 that shields the electric field during plating. This enhances the electric field shielding effect when the plate-shaped shielding member 47 is formed, and the easy-to-understand arrangement of the rotatable members 470 makes it easier to control the rotatable members 470.

[0036] 8, the plate-shaped shielding member 47 can be annular. This makes it possible to more reliably suppress variations in the electric field in the circumferential direction when the plate-shaped shielding member 47 is formed. The shape of the plate-shaped shielding member 47 is not particularly limited, and can be set appropriately depending on the position where it is desired to change the electric field during plating.

[0037] The radial range relative to the first axis of rotation Ax1 in which the rotatable member 470 is disposed may be outside 50% of the distance from the first axis of rotation Ax1 to the farthest end of the resistor 450 in the radial direction. This range may also be inside 90% of the distance from the first axis of rotation Ax1 to the farthest end of the resistor 450 in the radial direction. In one embodiment, the inner diameter of the plate-shaped shielding member 47 is 50% to 70% of the diameter of the resistor 450 or the substrate Wf, and preferably 55% to 65%. In another embodiment, the outer diameter of the plate-shaped shielding member 47 is 70% to 90% of the diameter of the resistor 450 or the substrate Wf, and preferably 80% to 90%. This allows the electric field to be efficiently adjusted in areas that are prone to causing a decrease in plating thickness uniformity, further improving the uniformity of the plating thickness formed on the substrate Wf.

[0038] The plating module 400 may include a drive mechanism 480 for rotating at least one rotatable member 470. The drive mechanism 480 may include an actuator such as a motor. The drive mechanism 480 may be controlled by a control module 800 ( FIG. 1 ), which is a controller that controls the operation of each part of the plating module 400. A separate drive mechanism 480 may be provided for each of the multiple rotatable members 470, and the rotation of each rotatable member 470 may be controlled independently. Alternatively, a single drive mechanism 480 may rotate multiple rotatable members 470, for example, by rotating a belt connecting the shafts 471 of the multiple rotatable members 470. By extending the shaft 472 to the outside of the plating tank 410, the electric field can be adjusted during plating without the need to remove the rotatable member 470 from the plating tank 410.

[0039] 9 is a conceptual diagram showing the rotatable member 470 as viewed from the anode side in the direction in which the first rotation axis Ax1 extends, and the through-hole 453 of the resistor 450. In Fig. 9, the through-hole 453 of the resistor 450, which is located behind the rotatable member 470 as viewed from the anode side, is schematically shown by a dashed line superimposed on the rotatable member 470.

[0040] Each of at least one rotatable member 470 is configured to be rotatable between a first position P1 where it overlaps with a portion of the multiple through holes 453 of the resistor 450 when viewed from the direction in which the first rotation axis Ax1 extends, and a second position P2 where the overlap between each of the rotatable members 470 and the multiple through holes 453 is smaller than that at the first position P1.

[0041] FIG. 9 shows an example of the rotatable member 470 at the first position P1. In FIG. 9, the plate-shaped main body 471 of the rotatable member 470 extends substantially parallel to a plane (first surface 451 in FIG. 4 ) perpendicular to the first rotation axis Ax1, on which the through-holes 453 are distributed. Therefore, the overlap between the rotatable member 470 and the through-holes 453 is larger than in the case of the rotatable member 470 at other rotation positions. When the rotatable member 470 is projected onto the first surface 451 of the resistor 450, the area where the projected rotatable member 470 and the through-holes 453 overlap is referred to as the overlap area. At the first position P1, the overlap area is larger than in the other rotation positions.

[0042] FIG. 10 is a schematic bottom view of a rotatable member 470 disposed obliquely with respect to the first rotation axis Ax1. FIG. 10 illustrates an example of the rotatable member 470 at an intermediate position P10, which is midway between the first position P1 and the second position P2. In FIG. 10, the through-holes 453 are omitted from the illustration to avoid clutter. In the example of FIG. 10, the plate-shaped main body 471 of the rotatable member 470 extends obliquely with respect to the first surface 451 of the resistor 450, on which the through-holes 453 are distributed. Therefore, the overlap between the rotatable member 470 and the through-holes 453 is smaller than that of the rotatable member 470 at the first position P1. In other words, the overlap area is smaller at the intermediate position P10 than at the first position P1.

[0043] Fig. 11 shows an example of the rotatable member 470 at the second position P2. In Fig. 11, the plate-shaped main body 471 of the rotatable member 470 extends substantially perpendicular to the first surface 451 of the resistor 450 on which the through-holes 453 are distributed, and therefore the overlap between the rotatable member 470 and the through-holes 453 is smaller than in the case of the rotatable member 470 at other rotation positions. In other words, the overlapping area is smaller at the second position P2 than in other rotation positions such as the first position P1 and the intermediate position P10.

[0044] In this way, the rotatable member 470 is configured to be rotatable between a first position P1 where it overlaps with a portion of the plurality of through holes 453 and a second position P2 where the overlap with the plurality of through holes 453 is smaller than that at the first position P1, so that the local plating current passing through the through holes 453 can be more reliably changed by rotating the rotatable member 470. Note that, although the rotation angle θ of the rotatable member 470 varies from 0° to 90° in the above example, the range of the rotation angle θ is not particularly limited as long as the plating current can be adjusted with the desired accuracy.

[0045] As shown in FIG. 3 , the plating module 400 includes a paddle 491 disposed between the substrate Wf held by the substrate holder 440 and the resistor 450, and a paddle stirring mechanism (not shown) for moving the paddle 491 through the plating solution to stir the plating solution. The paddle 491 may be configured, for example, as a plate member with a number of honeycomb-shaped holes formed therein, but is not limited thereto. The paddle stirring mechanism may be realized by a known mechanism such as a motor. The paddle stirring mechanism is configured to stir the plating solution near the plating surface Wf-a of the substrate Wf by reciprocating the paddle 491 along the plating surface Wf-a of the substrate Wf. However, the present invention is not limited to this example, and the paddle stirring mechanism may be configured, for example, to reciprocate the paddle 491 perpendicular to the plating surface Wf-a. Furthermore, although the present embodiment illustrates an example in which the paddle 491 and the paddle stirring mechanism are provided, the paddle 491 and the paddle stirring mechanism may not be provided.

[0046] A shield 492 is provided in the cathode region 422 to shield the current flowing from the anode 430 to the substrate Wf. In this embodiment, the shield 492 is provided at the same height as the paddle 491, but this is not limited to this example. The shield 492 is, for example, a substantially plate-shaped member made of a dielectric material. The shield 492 is configured to be movable between a shielding position interposed between the plating surface Wf-a of the substrate Wf and the anode 430 and a retracted position retracted from between the plating surface Wf-a and the anode 430. In other words, the shield 492 is configured to be movable between a shielding position below the plating surface Wf-a and a retracted position away from below the plating surface Wf-a. The position of the shield 492 is controlled by a shield driving mechanism (not shown) that receives commands from the control module 800. The shield driving mechanism can be realized by a known mechanism such as a motor or a solenoid.

[0047] The cathode region 422 is also provided with a sensor 460 that detects parameters related to the plating film formed on the plating surface Wf-a of the substrate Wf. In this embodiment, the sensor 460 is a film thickness sensor for measuring the thickness of the plating film, and the parameters related to the plating film refer to physical quantities for estimating the thickness of the plating film or the formation rate of the plating film. The sensor 460 is disposed so as to face the plating surface Wf-a. In this embodiment, the sensor 460 is configured to be movable so that its detection position can be changed in the radial direction relative to the first rotation axis Ax1. However, this is not limited to this example, and multiple sensors 460 facing the plating surface Wf-a may be provided. In addition, in one embodiment, the detection end of the sensor 460 is disposed inside the resistor 450. However, this is not limited to this example, and the sensor 460 may be disposed in another location outside the resistor 450, for example.

[0048] The detection signal from the sensor 460 is input to the control module 800 ( FIG. 1 ). In this embodiment, a potential sensor having a detection electrode (not shown) is used as the sensor 460. The detection electrode of the sensor 460 may be disposed so as to face the plating surface Wf-a, or may be disposed in a conduit that faces the plating surface Wf-a and is filled with plating solution. Furthermore, when a potential sensor is used as the sensor 460, at least one reference potential sensor (not shown) is preferably provided in the plating tank 410. The reference potential sensor is preferably provided outside the region between the substrate Wf and the anode 430. In other words, the reference potential sensor is preferably provided in a position that does not overlap the substrate Wf and the anode 430 when viewed from a direction perpendicular to the plating surface Wf-a of the substrate Wf. Based on the potential difference between the potential sensor 460, which is a potential sensor, and the reference potential sensor, the control module 800 can estimate the formation rate of the plating film formed on the surface Wf-a to be plated and measure the thickness of the plating film. This is based on the correlation between the plating current and the potential during the plating process. However, the sensor 460 may be any sensor capable of detecting parameters related to the plating film. Instead of or in addition to the potential sensor, other sensors such as an optical distance sensor (e.g., a white light confocal sensor), a magnetic field sensor, or an eddy current sensor may be used. While the present embodiment illustrates an example in which the sensor 460 is provided to detect parameters related to the plating film, the sensor 460 need not be provided.

[0049] The control module 800 can control the rotation of the rotatable member 470 based on the plating thickness obtained using the sensor 460. This makes it possible to adjust the resistance while checking the uniformity of the plating thickness being formed, thereby enabling the formation of a more uniform plating film.

[0050] The control module 800 may also control the rotation of the rotatable member 470 based on the size of the anode opening 427. For example, when the anode opening 427 is narrow, the position where the plating is likely to be thick is shifted radially inward with respect to the first rotation axis Ax1. Therefore, the control module 800 can control the rotatable member 470 so that the plate-shaped body 471 of the rotatable member 470 is nearly perpendicular to the first rotation axis Ax1 (so that the rotation angle θ is nearly 0°). From a similar perspective, when the anode opening 427 is wide, the control module 800 can control the plate-shaped body 471 so that it is nearly parallel to the first rotation axis Ax1 (so that the rotation angle θ is nearly 90°). Note that the control module 800 may control the rotation of the rotatable member 470 based on various plating conditions, such as the rotation speed of the substrate holder 440 or the measured or set value of the plating current.

[0051] In this way, during plating, the control module 800 can control the rotation of the at least one rotatable member 470 based on at least one of the thickness of the plating formed on the substrate Wf, the plating current, the rotation speed of the substrate holder 440, and the size of the anode opening 427. This allows for more precise adjustment of the plating current depending on various situations.

[0052] Here, the plating process in the plating module 400 of this embodiment will be described in more detail. The substrate Wf is exposed to the plating solution by immersing it in the plating solution in the cathode region 422 using the lifting mechanism 442. In this state, the plating module 400 can perform plating on the plating surface Wf-a of the substrate Wf by applying a voltage between the anode 430 and the substrate Wf. In one embodiment, the plating process is performed while the substrate holder 440 is rotated using the rotation mechanism 448. As a result of the plating process, a conductive film (plating film) is deposited on the plating surface Wf-a of the substrate Wf.

[0053] The control module (controller) 800 of this embodiment controls the drive mechanism 480 ( FIG. 8 ) to adjust the rotation of the rotatable member 470, thereby improving the uniformity of the plating film thickness distribution across the entire substrate Wf. As an example, the adjustment of the rotatable member 470 using the drive mechanism 480 is performed before the plating process begins. Also, as another example, the adjustment of the rotatable member 470 using the drive mechanism 480 is performed in real time during the plating process based on the detection value by the sensor 460.

[0054] FIG. 12 is a flowchart illustrating an example of a method for setting operation recipes for the rotatable member 470, the anode mask 426, and the shield 492 by the control module 800. The method illustrated in FIG. 12 is executed, for example, when processing a new substrate lot. The control module 800 may set operation recipes for only some of the rotatable member 470, the anode mask 426, and the shield 492. The operation recipe for the rotatable member 470 may be a recipe that indicates the rotation angle θ of the rotatable member 470. The operation recipe for the anode mask 426 may be a recipe that indicates the opening dimensions of the anode mask 426. The operation recipe for the shield 492 may be a recipe that indicates the advance / retract position of the shield 492. Instead of being set by the control module 800 of the plating apparatus 1000, the operation recipes may be set by a computer external to the plating apparatus 1000 and transmitted to the plating apparatus 1000.

[0055] In the example shown in FIG. 12 , the control module 800 first acquires a resist pattern for the substrate Wf to be processed (step S110). The resist pattern refers to a pattern of a resist layer formed on the surface Wf-a to be plated so that a desired plating pattern is formed by plating. The resist pattern may be acquired by detecting the substrate Wf using a sensor provided in the plating apparatus 1000. As an example, the plating apparatus 1000 may be equipped with an imaging sensor (not shown), such as a camera, that captures an image of the surface Wf-a to be plated of the substrate Wf. The control module 800 may then acquire imaging data detected by the imaging sensor and analyze the imaging data to acquire the resist pattern for the surface Wf-a to be plated. The resist pattern may be acquired from the imaging data using a known method based on shading or feature points of the imaging data. Alternatively, the control module 800 may acquire the resist pattern via external input via wired or wireless communication, for example.

[0056] The control module 800 then sets operation recipes for the rotatable member 470, the anode mask 426, and the shield 492 based on the acquired resist pattern (step S120). As a specific example, the control module 800 calculates a plating growth coefficient for each predetermined region of the plating surface Wf-a of the substrate Wf based on the acquired resist pattern, and sets operation recipes for each control object based on the calculated plating growth coefficient. Here, the plating growth coefficient is a parameter indicating the growth rate (formation rate) of the plating film when the rotatable member 470, the anode mask 426, and the shield 492 each block the current to the minimum extent. As an example, the plating growth coefficient can be expressed as the amount (e.g., nanometers) of plating film formed per unit time (e.g., 1 second). As a specific example, the control module 800 can calculate the aperture ratio of the resist layer for each predetermined region based on the resist pattern, and then calculate the plating growth coefficient based on the calculated aperture ratio. This is because in areas where the aperture ratio of the resist layer is large, the area on which plating is deposited and the amount of plating required to form a certain amount of plating film are large, and the growth rate of the plating film tends to be slower than in areas where the aperture ratio of the resist layer is small.

[0057] FIG. 13 is a schematic diagram illustrating a resist pattern formed on the plating surface Wf-a of a substrate Wf according to one embodiment. In FIG. 13 , resist openings are formed only in the cross-shaped region A1, which is hatched, and the region A2 outside the cross-shaped region A1 is a non-opening region where no resist openings are formed. When plating is performed on a substrate Wf with such a resist pattern, plating current does not flow through the non-opening region A2, but only through the opening region A1. In this embodiment, plating is performed while rotating the substrate holder 440 using the rotation mechanism 448. The plating current concentrates in the cross-shaped convex region of region A1, particularly in the circumferential direction, including region A2, resulting in a large plating film thickness. In this specification, the region in which resist openings are formed substantially entirely when viewed circumferentially is referred to as the "central region B1" (in the example shown in FIG. 13 , the circular region surrounded by the inner dashed line C1). Furthermore, when viewed in the circumferential direction, a region that includes both a region where a resist opening is formed (opening region A1) and a region where a resist opening is not formed (non-opening region A2), and where the area of ​​the opening region A1 is larger in the circumferential direction than the area of ​​the non-opening region A2, is called an "intermediate region B2" (in the example shown in FIG. 13, this is an annular region surrounded by dashed-dotted lines C1 and C2). Furthermore, when viewed in the circumferential direction, a region that includes both the opening region A1 and the non-opening region A2, and where the area of ​​the opening region A1 is smaller in the circumferential direction than the area of ​​the non-opening region A2, is called an "outer peripheral region B3" (in the example shown in FIG. 13, this is an annular region surrounded by dashed-dotted lines C2 and C3). In the example shown in FIG. 13, the central region B1, intermediate region B2, and outer peripheral region B3 are located in this order from the center to the outer periphery of the plating surface Wf-a, and no resist opening is formed on the outer periphery of the outer peripheral region B3. However, this is not limited to this example, and any resist pattern may be formed on the substrate Wf.

[0058] Here, the anode mask 426 or the shield 492 provided in the plating module 400 can suitably adjust the plating film formation rate near the outer periphery of the plating surface Wf-a. However, when plating is performed on a substrate Wf as shown in Figure 13, the plating film formation rate in the region (particularly the middle region B2) that is closer to the inner periphery than near the outer periphery may be relatively higher, which may impair the uniformity of the thickness of the plating film.

[0059] In contrast, in the plating module 400 of this embodiment, the rotatable member 470 forms a circular shielding member 47, allowing adjustment of the electric field primarily in the region where the shielding member 47 is located. This allows the plating speed in the intermediate region B2 to be adjusted by adjusting the current flowing through the intermediate region B2. For example, in the substrate Wf of FIG. 13 , if the plating speed in the intermediate region B2 surrounded by the dashed lines C1 and C2 is relatively high, the plating thickness in the intermediate region B2 can be reduced by adjusting the rotation angle θ of the rotatable member 470 closer to 0°. This allows for improved thickness uniformity in the plating film, even when plating the substrate Wf shown in FIG. 13 . Additionally, the plating module 400 of this embodiment includes an anode mask 426 and a shield 492. This allows the plating speed in the intermediate region B2 to be adjusted by rotating the rotatable member 470, and the plating speed in the peripheral region B3 to be adjusted by the anode mask 426 and the shield 492. Therefore, the plating speed can be adjusted for each region of the substrate Wf by controlling the resistor 450, the anode mask 426, and the shield 492, thereby improving the uniformity of the thickness of the plating film. Note that the dimensions of the rotatable member 470 may be determined based on the intermediate region B2, such as by setting the shielding member 47 to have approximately the same dimensions as the intermediate region B2.

[0060] Fig. 14 is a flowchart showing an example of a method for setting an operation recipe for the rotatable member 470, the anode mask 426, and the shield 492 during a plating process by the control module 800. The method shown in Fig. 14 is executed during a plating process in place of the method shown in Fig. 12 or to modify the operation recipe set by the method shown in Fig. 12. Note that the control module 800 may set operation recipes for only some of the rotatable member 470, the anode mask 426, and the shield 492.

[0061] When the plating process begins (step S210), the control module 800 acquires plating film parameters from the sensor 460 in real time (step S220). In this embodiment, the sensor 460 detects the plating film parameters as the substrate Wf rotates. In one embodiment, the sensor 460 detects the plating film parameters at multiple points along the radial direction on the plating surface Wf-a. The control module 800 calculates the thickness distribution of the plating film on the plating surface Wf-a based on the values ​​detected by the sensor 460 (step S230). Next, the control module 800 sets an operation recipe for the rotatable member 470, the anode mask 426, and the shield 492 based on the calculated thickness distribution (step S240). The control module 800 repeats steps S220 to S240 until the plating process is completed (step S250), setting the operation recipe for the controlled object. The control module 800 then controls the rotatable member 470, the anode mask 426, and the shield 492 based on the set operation recipe. In this way, the uniformity of the thickness of the plating film can be further improved by setting or modifying the operating recipe of the rotatable member 470, etc. during the plating process based on parameters related to the plating film obtained from the sensor 460.

[0062] <Modification 1> In the above embodiment, the plate-like shielding member 47 is annular, but it may be disk-shaped.

[0063] FIG. 15 is a schematic bottom view showing a rotatable member 470A of this modification, as viewed from the anode side. The rotatable member 470A differs from the rotatable member 470 of the above-described embodiment in that it includes a plate-shaped main body 471A instead of the plate-shaped main body 471. In the illustrated example, when the plate-shaped main bodies 471A of the multiple rotatable members 470A are parallel to each other, they integrally form a disk-shaped shielding member 47A. In this manner, when each of the multiple rotatable members 470A is in a predetermined rotational position, the multiple rotatable members 470A may integrally form a disk-shaped shielding member 47A. This allows for localized adjustment of the plating current in the region around the first rotation axis Ax1.

[0064] <Modification 2> In the above-described embodiment, the plating module 400 constitutes a cup-type plating apparatus, but it may also constitute a dip-type plating apparatus. In this case, the substrate Wf, the resistor 450, the rotatable member 470, and the anode 430 can each be arranged vertically. This modification can also achieve the same effects as the above-described embodiment.

[0065] The present invention can also be described as the following aspects: [Aspect 1] According to Aspect 1, there is provided a plating apparatus comprising: a plating tank; a substrate holder configured to hold a substrate and to be rotatable about a first rotation axis during plating; an anode disposed in the plating tank so as to face the substrate held by the substrate holder; a resistor for adjusting an electric field disposed between the anode and the substrate holder, the resistor having a plurality of through holes communicating with the anode side and the substrate holder side of the resistor; and at least one rotatable member for adjusting the electric field disposed between the anode and the resistor, each of the at least one rotatable member being rotatable about a second rotation axis extending in a direction intersecting the first rotation axis, and each of the at least one rotatable member being rotatable between a first position where the rotatable member overlaps with a portion of the through holes in the resistor and a second position where the overlap between the rotatable member and the through holes is smaller than at the first position, as viewed in the direction of extension of the first rotation axis. According to the first aspect, it is possible to improve the uniformity of the thickness of the plating film formed on the object to be plated.

[0066] [Mode 2] According to Mode 2, the second rotation axis is substantially perpendicular to the first rotation axis in Mode 1. According to Mode 2, it is possible to increase the change in electric field caused by the rotation of the rotatable member, and to further improve the uniformity of the thickness of the plating film formed on the object to be plated.

[0067] [Mode 3] According to Mode 3, in Mode 1 or 2, each of the at least one rotatable member includes a plate-shaped main body and a shaft extending from the main body. According to Mode 3, the plate-shaped main body can increase the change in electric field due to rotation, and the uniformity of the thickness of the plating film formed on the object to be plated can be further improved.

[0068] [Mode 4] According to Mode 4, in any one of Modes 1 to 3, the plating apparatus includes a plurality of the rotatable members, and when each of the plurality of rotatable members is in a predetermined rotation position, the plurality of rotatable members integrally form a plate-shaped shielding member that shields an electric field during plating. According to Mode 4, when the plate-shaped shielding member is formed, the effect of shielding the electric field can be enhanced, and the easy-to-understand arrangement of the rotatable members makes it easier to control the rotatable members.

[0069] [Mode 5] According to Mode 5, in Mode 4, the plate-like shielding member is disk-shaped or annular. Since the plating formation speed may depend on the distance from the center of the object, Mode 5 can particularly improve the uniformity of the thickness of the formed plating in such cases.

[0070] [Mode 6] According to Mode 6, in any of Modes 1 to 5, the plating apparatus further includes a sensor for measuring a thickness of the plating formed on the substrate, a drive mechanism for rotating the at least one rotatable member, a controller for controlling the drive mechanism, and an anode mask disposed between the at least one rotatable member and the anode, the anode mask having an anode opening penetrating the anode side and the substrate holder side of the anode mask, the anode opening being configured to be adjustable in size, wherein the controller controls the rotation of the at least one rotatable member during plating based on at least one of the thickness of the plating formed on the substrate, the plating current, the rotation speed of the substrate holder, and the size of the anode opening. According to Mode 6, the plating current can be adjusted more precisely depending on various situations.

[0071] [Mode 7] According to Mode 7, in any one of Modes 1 to 6, the substrate holder is configured to hold the substrate in the plating tank with the surface to be plated facing downward. According to Mode 7, plating can be performed by taking advantage of the advantages of a cup-type plating device.

[0072] Although the embodiments of the present invention have been described above, the above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention naturally includes equivalents thereof. Furthermore, any combination of the embodiments and modifications is possible within the scope of solving at least part of the above-described problems or achieving at least part of the effects, and any combination or omission of the components described in the claims and specification is possible.

[0073] 47, 47A...Shielding member 400...Plating module 410...Plating tank 420...Membrane 422...Cathode region 424...Anode region 426...Anode mask 427...Anode opening 430...Anode 440...Substrate holder 442...Lifting mechanism 448...Rotation mechanism 450...Resistor 453...Through-hole 460...Sensor 470, 470A...Rotatable member 471, 471A...Main body of rotatable member 472...Shaft 480...Drive mechanism 492...Shielding body 800...Control module 1000...Plating apparatus Ax1...First rotation axis Ax2...Second rotation axis P1...First position P2...Second position Wf...Substrate Wf-a...Surface to be plated

Claims

1. A plating apparatus comprising: a plating tank; a substrate holder configured to hold a substrate and to be rotatable around a first rotation axis during plating; an anode arranged in the plating tank so as to face the substrate held in the substrate holder; a resistor for adjusting an electric field arranged between the anode and the substrate holder, the resistor having a plurality of through holes communicating with the anode side and the substrate holder side of the resistor; and at least one rotatable member for adjusting an electric field arranged between the anode and the resistor, wherein each of the at least one rotatable member is configured to be rotatable around a second rotation axis extending in a direction intersecting the first rotation axis, and each of the at least one rotatable member is configured to be rotatable between a first position where it overlaps with a portion of the plurality of through holes in the resistor, when viewed in the direction in which the first rotation axis extends, and a second position where the overlap between each of the rotatable members and the plurality of through holes is smaller than at the first position.

2. The plating apparatus according to claim 1, wherein the second rotation axis is substantially perpendicular to the first rotation axis.

3. The plating apparatus of claim 1, wherein each of said at least one rotatable member comprises a plate-shaped body and a shaft extending from said body.

4. The plating apparatus according to any one of claims 1 to 3, comprising a plurality of the rotatable members, and when each of the plurality of rotatable members is in a predetermined rotational position, the plurality of rotatable members integrally form a plate-shaped shielding member that shields the electric field during plating.

5. The plating apparatus according to claim 4, wherein the plate-shaped shielding member is disk-shaped or annular.

6. The plating apparatus of any one of claims 1 to 3, further comprising: a sensor for measuring the thickness of the plating formed on the substrate; a drive mechanism for rotating the at least one rotatable member; a controller for controlling the drive mechanism; and an anode mask disposed between the at least one rotatable member and the anode, the anode mask having an anode opening penetrating the anode side and the substrate holder side of the anode mask, the anode opening being configured to be adjustable in size, wherein the controller controls the rotation of the at least one rotatable member during plating based on at least one of the thickness of the plating formed on the substrate, the plating current, the rotation speed of the substrate holder, and the size of the anode opening.

7. A plating apparatus according to any one of claims 1 to 3, wherein the substrate holder is configured to hold the substrate in the plating tank with the surface to be plated facing downward.

Images