SUBSTRATE HOLDER, APPARATUS FOR PLATING, AND METHOD OF MANUFACTURING APPARATUS FOR PLATING

TECHNICAL FIELD

The present disclosure relates to a substrate holder, an apparatus for plating, and a method of manufacturing the apparatus for plating.

BACKGROUND ART

A cup-type electroplating apparatus has been known as one example of the apparatus for plating. The cup-type electroplating apparatus soaks a substrate (for example, a semiconductor wafer) held by a substrate holder in such a manner that a surface to be plated or a plating surface of the substrate faces down, in a plating solution and applies a voltage between the substrate and anode to make a conductive film (plating film) deposit on a surface of the substrate. In such plating apparatus, it is known that the density of electric lines of force (electric field) to the plating surface of the substrate during plating affects the uniformity in the thickness of the plating film. U.S. Pat. No. 6,193,859 (PTL 1) describes a substrate holder that is provided with a flange below a seal holder configured to hold a seal for protecting a contact for power feed to a substrate and that is configured to adjust the thickness of a plating film at an edge portion of the substrate by changing an opening diameter of the flange.

CITATION LIST
Patent Literatures

PTL1: U.S. Pat. No. 6,193,859

SUMMARY OF INVENTION
Technical Problem

The PTL 1 described above, however, has no argument on the effects of the configuration of the seal and the seal holder of the substrate on the uniformity in the thickness of the plating film. The seal and the seal holder of the substrate holder are provided as ring-shaped members having openings which cause the plating surface of the substrate to be exposed to the plating solution. In a general configuration, with a view to allowing the seal holder to appropriately hold the seal, the opening diameter of the seal holder is made smaller than the opening diameter of the seal. This difference in the opening diameter between the seal and the seal holder is likely to affect the density of electric lines of force (electric field) to the plating surface of the substrate and thereby affect the uniformity in the thickness of the plating film.

One object of the present disclosure is to provide the configuration of a seal and a seal holder of a substrate holder that enhance the uniformity in the thickness of a plating film.

Solution to Problem

According to one aspect of the present disclosure, there is provided a substrate holder configured to hold a substrate in such a manner that a surface to be plated or a plating surface of the substrate faces down, in an apparatus for plating. The substrate holder comprises a seal configured to seal an outer peripheral part of the substrate and provided with a first opening which the plating surface of the substrate is exposed on; and a seal ring holder configured to hold the seal and provided with a second opening which the plating surface of the substrate is exposed on, wherein an opening diameter ratio that is a ratio of an opening diameter of the second opening to an opening diameter of the first opening is in a range of not lower than 99.32% and not higher than 99.80%.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating the overall configuration of a plating apparatus according to an embodiment;

FIG. 2 is a plan view illustrating the overall configuration of the plating apparatus according to the embodiment;

FIG. 3 is a schematic diagram illustrating one example of a plating module according to the embodiment;

FIG. 4 is a schematic diagram illustrating the configuration of a substrate holder according to the embodiment;

FIG. 5 is an explanatory view illustrating electric lines of force in the vicinity of a substrate;

FIG. 6 is tables showing examples of results of a simulation with regard to in-plane uniformity in the thickness of a plating film;

FIG. 7 is tables showing ratios of an opening diameter of an SRH to an opening diameter of a seal in the examples of the results of the simulation;

FIG. 8 is an explanatory view illustrating a method of calculating the in-plane uniformity;

FIG. 9 is graphs showing examples of results of a simulation with regard to the thickness of the plating film;

FIG. 10A is a schematic diagram illustrating the configuration of a substrate holder according to a modification;

FIG. 10B is a schematic diagram illustrating the configuration of a substrate holder according to another modification; and

FIG. 10C is a schematic diagram illustrating the configuration of a substrate holder according to another modification.

DESCRIPTION OF EMBODIMENTS

The following describes embodiments of the present disclosure with reference to drawings. In the drawings described below, identical or equivalent components are expressed by like reference signs, and duplicated description is omitted.

FIG. 1 is a perspective view illustrating the overall configuration of the plating apparatus of this embodiment. FIG. 2 is a plan view illustrating the overall configuration of the plating apparatus of this embodiment. As illustrated in FIGS. 1 and 2, a plating apparatus 1000 includes load ports 100, a transfer robot 110, aligners 120, pre-wet modules 200, pre-soak modules 300, plating modules 400, cleaning modules 500, spin rinse dryers 600, a transfer device 700, and a control module 800.

The load port 100 is a module for loading a substrate housed in a cassette, such as a FOUP, (not illustrated) to the plating apparatus 1000 and unloading the substrate from the plating apparatus 1000 to the cassette. While the four load ports 100 are arranged in the horizontal direction in this embodiment, the number of load ports 100 and arrangement of the load ports 100 are arbitrary. The transfer robot 110 is a robot for transferring the substrate that is configured to grip or release the substrate between the load port 100, the aligner 120, the pre-wet module 200, and the spin rinse dryers 600. The transfer robot 110 and the transfer device 700 can perform delivery and receipt of the substrate via a temporary placement table (not illustrated) to grip or release the substrate between the transfer robot 110 and the transfer device 700.

The aligner 120 is a module for adjusting a position of an orientation flat, a notch, and the like of the substrate in a predetermined direction. While the two aligners 120 are disposed to be arranged in the horizontal direction in this embodiment, the number of aligners 120 and arrangement of the aligners 120 are arbitrary. The pre-wet module 200 wets a surface to be plated of the substrate before a plating process with a process liquid, such as pure water or deaerated water, to replace air inside a pattern formed on the surface of the substrate with the process liquid. The pre-wet module 200 is configured to perform a pre-wet process to facilitate supplying the plating solution to the inside of the pattern by replacing the process liquid inside the pattern with a plating solution during plating. While the two pre-wet modules 200 are disposed to be arranged in the vertical direction in this embodiment, the number of pre-wet modules 200 and arrangement of the pre-wet modules 200 are arbitrary.

For example, the pre-soak module 300 is configured to remove an oxidized film having a large electrical resistance present on, a surface of a seed layer formed on the surface to be plated of the substrate before the plating process by etching with a process liquid, such as sulfuric acid and hydrochloric acid, and perform a pre-soak process that cleans or activates a surface of a plating base layer. While the two pre-soak modules 300 are disposed to be arranged in the vertical direction in this embodiment, the number of pre-soak modules 300 and arrangement of the pre-soak modules 300 are arbitrary. The plating module 400 performs the plating process on the substrate. There are two sets of the 12 plating modules 400 arranged by three in the vertical direction and by four in the horizontal direction, and the total 24 plating modules 400 are disposed in this embodiment, but the number of plating modules 400 and arrangement of the plating modules 400 are arbitrary.

The cleaning module 500 is configured to perform a cleaning process on the substrate to remove the plating solution or the like left on the substrate after the plating process. While the two cleaning modules 500 are disposed to be arranged in the vertical direction in this embodiment, the number of cleaning modules 500 and arrangement of the cleaning modules 500 are arbitrary. The spin rinse dryer 600 is a module for rotating the substrate after the cleaning process at high speed and drying the substrate. While the two spin rinse dryers are disposed to be arranged in the vertical direction in this embodiment, the number of spin rinse dryers and arrangement of the spin rinse dryers are arbitrary. The transfer device 700 is a device for transfer the substrate between the plurality of modules inside the plating apparatus 1000. The control module 800 is configured to control the plurality of modules in the plating apparatus 1000 and can be configured of, for example, a general computer including input/output interfaces with an operator or a dedicated computer.

An example of a sequence of the plating processes by the plating apparatus 1000 will be described. First, the substrate housed in the cassette is loaded on the load port 100. Subsequently, the transfer robot 110 grips the substrate from the cassette at the load port 100 and transfers the substrate to the aligners 120. The aligner 120 adjusts the position of the orientation flat, the notch, or the like of the substrate in the predetermined direction. The transfer robot 110 grips or releases the substrate whose direction is adjusted with the aligners 120 to the pre-wet module 200.

The pre-wet module 200 performs the pre-wet process on the substrate. The transfer device 700 transfers the substrate on which the pre-wet process has been performed to the pre-soak module 300. The pre-soak module 300 performs the pre-soak process on the substrate. The transfer device 700 transfers the substrate on which the pre-soak process has been performed to the plating module 400. The plating module 400 performs the plating process on the substrate.

The transfer device 700 transfers the substrate on which the plating process has been performed to the cleaning module 500. The cleaning module 500 performs the cleaning process on the substrate. The transfer device 700 transfers the substrate on which the cleaning process has been performed to the spin rinse dryer 600. The spin rinse dryer 600 performs the drying process on the substrate. The transfer robot 110 receives the substrate from the spin rinse dryer 600 and transfers the substrate, on which the drying process is performed, to the cassette at the load port 100. Finally, the cassette housing the substrate is unloaded from the load port 100.

FIG. 3 is a schematic diagram illustrating one example of a plating module according to this embodiment. As shown in this drawing, the plating module 400 according to the embodiment is a face down-type or a cup-type plating module. The plating solution is, for example, a copper sulfate solution, and the plating film is, for example, a copper film. The plating film may, however, be a film of any metal usable for plating, and the plating solution may be selected according to the type of the plating film.

The plating module 400 includes a plating tank 401, a substrate holder 403 serving as a substrate holding tool, and a plating solution reservoir 404. The substrate holder 403 is configured such that a substrate 402 such as a wafer is held with a surface to be plated or a plating surface thereof faces down. The plating module 400 includes a motor 411 provided to rotate the substrate holder 403 in a circumferential direction. The motor 411 receives supply of electric power from a non-illustrated power source. The motor 411 is controlled by the control module 800 to rotate the substrate holder 403 and the substrate 402 held by the substrate holder 403. In other words, the control module 800 controls the rotation of the motor 411, so as to control the number of rotations per unit time (also referred to as frequency or rotation speed) of the substrate 402. Rotating the substrate 402 forms a liquid flow of the plating solution in the vicinity of a surface of the substrate and thereby enables a sufficient amount of ion to be uniformly supplied to the substrate 402. An anode 410 is placed to be opposed to the substrate 402 in the plating tank 401. The anode 410 may be provided with an anode mask (not shown) configured to adjust an exposed area of the anode 410.

The plating module 400 further includes a plating solution receiving tank 408. The plating solution in the plating solution reservoir 404 is supplied by a pump 405 through a filter 406 and a plating solution supply tube 407 via a bottom of the plating tank 401 into the plating tank 402. The plating solution overflowing from the plating tank 401 is received by the plating solution receiving tank 408 and is returned to the plating solution reservoir 404.

The plating module 400 also includes a power supply 409 that is connected with the substrate 402 and the anode 410. While the motor 411 rotates the substrate holder 403, the power supply 409 applies a predetermined voltage (DC voltage, pulse voltage) between the substrate 402 and the anode 410. This causes plating current to flow between the anode 410 and the substrate 402 and forms a plating film on the plating surface of the substrate 402.

Furthermore, a plate (resistor) 10 provided with a plurality of holes and used for regulation of an electric field is placed between the substrate 402 and the anode 410. The plurality of holes are pierced between a front face and a rear face of the plate 10 and form a path which the plating solution and the ion included in the plating solution pass through. A resistance value of the plate 10 (a resistance value relative to the ion flow or the plating current) is adjustable by regulating an opening density defined by the plurality of holes.

A paddle 412 is placed between the substrate 402 and the plate 10. The paddle 412 is driven by a drive mechanism 413 to reciprocate parallel to the substrate 402 (in an approximately horizontal direction), so as to stir the plating solution and form a stronger liquid flow on the surface of the substrate 402. This enables a sufficient amount of the ion to be uniformly supplied to the substrate 402. The drive mechanism 413 includes a motor 413a configured to receive supply of electric power from a non-illustrated power source, a rotation-linear motion conversion mechanism 413b, such as a ball screw, configured to convert the rotation of the motor 413a into linear motion, and a shaft 413c linked with the rotation-linear motion conversion mechanism 413b and the paddle 412 to transmit the power of the rotation-linear motion conversion mechanism 413b to the paddle 412. The control module 800 controls the rotation of the motor 413a, so as to control the speed of the reciprocating motion (motion speed) of the paddle 412.

FIG. 4 is a schematic diagram illustrating the configuration of the substrate holder according to the embodiment. The substrate holder 403 includes a contact (not shown) that comes into contact with an outer peripheral part of the substrate 402 to supply electricity, a seal 421 provided as a ring-shaped member to seal the contact, and a seal ring holder (SRH) 422 provided as one example of a seal holder to hold the seal 421. The seal 421 comes into contact with the outer peripheral part of the substrate 402 or an inner side of the outer peripheral part and seals the outer peripheral part of the substrate 402, so as to prevent invasion of the plating solution to a contact point between the contact and the substrate 402. The configuration that the seal 421 comes into contact with the substrate 402 and that the SRH 422 presses the seal 421 against the substrate 402 prevents the plating solution from entering the contact side. The seal 421 has an opening 431 having an opening diameter ϕseal, in order to expose the plating surface of the substrate 402. The SRH 422 has an opening 432 having an opening diameter ϕsrh, in order to expose the plating surface of the substrate 402. As shown in FIG. 4, the opening diameter ϕsrh of the SRH 422 is made smaller than the opening diameter ϕseal of the seal 421 (ϕsrh<ϕseal), so that the SRH 422 can hold the seal 421.

FIG. 5 is an explanatory view illustrating electric lines of force in the vicinity of the substrate. The voltage applied between the substrate 402 and the anode 410 forms electric lines of force (electric field) from the anode 410 toward the substrate 402. As understood from FIG. 4 and FIG. 5, the electric lines of force (electric field) shown by arrows are restricted at the opening 432 of the SRH 422 and are spread at the opening 431 of the seal 421, because of a difference between the opening diameter ϕsrh of the SRH 422 and the opening diameter ϕseal of the seal 421. The applicant has accordingly controlled the in-plane uniformity in the thickness of the plating film on the surface of the substrate by controlling a relationship between the opening diameter ϕseal of the seal and opening diameter ϕsrh of the SRH. More specifically, the applicant has found that the in-plane uniformity in the thickness of the plating film on the surface of the substrate is enhanced by the balance between the restriction of the electric field by the SRH 422 and the spread of the electric field by the seal 421 and has determined an optimum relationship between the opening diameters ϕsrh and ϕseal that uniformizes a plating film thickness distribution (a range of an opening diameter ratio=ϕsrh/ϕseal described later).

As shown in FIG. 5, a height Hseal of the seal and a height Hsrh of the SRH, as well as the opening diameter of the seal and the opening diameter of the SRH, are expected to affect the electric lines of force (electric field). The applicant has accordingly defined a height of a bank Hbank=Hseal+Hsrh formed by the seal 421 and the SRH 422 and has verified the effects of the height of the bank Hbank on the electric field. With a view to forming a strong flow of the plating solution on the surface of the substrate 402, it is desirable to reduce the distance between the substrate 402 and the paddle 412 as short as possible. For this purpose, there is a need to reduce the height of the bank, in order to prevent the paddle 412 from colliding with the bank. In terms of the function of the SRH 422 that presses the seal 421 against the substrate 402 to prevent invasion of the plating solution, on the other hand, the SRH 422 is required to have such a mechanical strength that sufficiently withstands a reactive force caused by compression of the seal 421, and accordingly needs to have a certain level of thickness (height of the bank). By taking into account the balance of these requirements, the height of the bank is preferably in a range of 2.0 mm Hbank 3.0 mm and is more preferably about 2.5 mm.

FIG. 6 shows examples of results of a simulation with regard to the in-plane uniformity in the thickness of the plating film. This simulation may be performed by using a commercially available or exclusive plating analysis software/program. Parameters including the module structure of the plating module (including the materials, the shapes, the dimensions and/or the layout of the seal and the SRH), the applied voltage and the type of the plating solution are set as analysis conditions (model) of the simulation. For example, COMSOL Multiphysics (registered trademark) may be used as the analysis software. This simulation changed the combination of the sizes of the opening diameter ϕsrh of the SRH and the opening diameter ϕseal of the seal, calculated a plating film thickness distribution (shown in FIG. 9) obtained as a result of electroplating of a circular wafer having a diameter of 300 mm, and calculated an in-plane uniformity U from this plating film thickness distribution. The height of the bank Hbank was 2.5 mm (the height of the seal Hseal=1 mm and the height of the SRH Hsrh=1.5 mm). The height of the seal herein denotes the height of the seal 421 pressed against the substrate 402 and crushed, while the SRH 422 holding the seal 421 is fixed to the main body of the substrate holder by screwing or the like. These numerical values are design values. It should be noted that numerical values in an actual substrate holder are likely to include slight deviations, due to, for example, deformation of the SRH 422 by the reactive force of the seal 421 and/or the dimensional tolerances of the seals 421 and the SRH 422. FIG. 6(A) shows the results of a simulation with regard to in-plane uniformity U in the case of plating a wafer of 300 mm in diameter having a Cu layer of 300 nm in film thickness as a seed layer by changing the combination of the sizes of the opening diameter of the SRH and the opening diameter of the seal. FIG. 6(B) shows the results of the simulation with regard to in-plane uniformity U in the case of plating a wafer of 300 mm in diameter having a Cu layer of 50 nm in film thickness as a seed layer by changing the combination of the sizes of the opening diameter of the SRH and the opening diameter of the seal.

FIG. 8 is an explanatory view illustrating a method of calculating the in-plane uniformity. In the graph, the abscissa indicates the position in the radial direction of the substrate, and the ordinate indicates the thickness of the plating film. The thickness of the plating film shown on the ordinate is normalized by an average film thickness of the entire substrate. The average film thickness of the entire substrate may be an average value of film thickness when an arbitrary number of measurement points (sampling points) of the film thickness are set in a plane of the substrate. In this graph, Tmax, Tmin and Tavg respectively denote a maximum value in the thickness of the plating film, a minimum value in the thickness of the plating film, and an average value in the thickness of the plating film when an arbitrary number of measurement points (sampling points) of the film thickness are set in the plane of the substrate. According to this embodiment, the in-plane uniformity U in the thickness of the plating film is calculated by using Expression (1) given below. The higher degree of uniformity in the thickness of the plating film provides the smaller value of the in-plane uniformity U. The uniformity in the thickness of the plating film U=0% in an ideal case (in the case where the thickness of the plating film is identical in the entire substrate).

U[%]=(Tmax−Tmin)/2/Tavg*100 (1)

FIG. 9 shows examples of results of a simulation with regard to the thickness of the plating film. In the graphs, the abscissa indicates the position in the radial direction of the substrate, and the ordinate indicates the thickness of the plating film. The thickness of the plating film shown on the ordinate is normalized by an average film thickness of the entire substrate. The average film thickness of the entire substrate may be an average value of film thickness when an arbitrary number of measurement points (simulation points) of the film thickness are set in a plane of the substrate. These graphs show the results of the simulation with regard to a film thickness distribution corresponding to part of the examples of the simulation results shown in FIG. 6. FIG. 9(A) shows an example of results of a simulation in the thickness of the plating film when the opening diameter ϕseal=295.2 mm of the seal and the opening diameter ϕsrh=293.8 mm of the SRH in a wafer of 300 mm in diameter having a Cu seed layer of 300 nm in the film thickness. The in-plane film thickness U=0.56% in this example. FIG. 9(B) shows an example of results of the simulation in the thickness of the plating film when the opening diameter ϕseal=294.8 mm of the seal and the opening diameter ϕsrh=294.5 mm of the SRH in the wafer of 300 mm in diameter having the Cu seed layer of 300 nm in the film thickness. The in-plane film thickness U=1.84% in this example. FIG. 9(C) shows an example of results of the simulation in the thickness of the plating film when the opening diameter ϕseal=295.3 mm of the seal and the opening diameter ϕsrh=293.3 mm of the SRH in the wafer of 300 mm in diameter having the Cu seed layer of 300 nm in the film thickness. The in-plane film thickness U=1.70% in this example. These examples of the results of the simulation shown in FIG. 9 show that changing the combination of the sizes of the opening diameter of the seal and the opening diameter of the SRH varies the plating film thickness distribution on the substrate and significantly varies the plating film thickness distribution especially in an outer peripheral part of the substrate.

FIG. 6 shows the results of calculation of the in-plane uniformity U by Expression (1) shown in FIG. 9 and given above when the plating film thickness distributions as illustrated in FIG. 9 are obtained by the simulation with regard to the respective combinations of the opening diameter ϕseal of the seal and the opening diameter ϕsrh of the SRH. FIG. 6 shows that the uniformity in the thickness of the plating film (the in-plane uniformity U) is varied by changing the combination of the sizes of the opening diameter of the seal and the opening diameter of the SRH. In these illustrated examples, a desired condition of the in-plane uniformity is determined as in-plane uniformity UK 1.5%, and an opening diameter ratio R expressed by Expression (2) given below is calculated with regard to combinations of the opening diameter ϕsrh of the SRH and the opening diameter ϕseal of the seal that satisfy the in-plane uniformity U≤1.5%. According to the embodiment, ϕsrh<ϕseal as described above, so that the opening diameter ratio R<1.

Opening diameter ratio R=ϕsrh/ϕseal×100[%] (2)

FIG. 7 is tables showing the ratios of the opening diameter of the SRH to the opening diameter of the seal in the examples of the results of the simulation shown in FIG. 6. In these tables, a numerical value in each field shows an opening diameter ratio R corresponding to each combination of the opening diameter of the SRH and the opening diameter of the seal. These tables also show the opening diameter ratios R corresponding to the respective combinations of the opening diameter of the SRH and the opening diameter of the seal that do not satisfy the in-plane uniformity U≤1.5%. The fields in grayed background show the opening diameter ratios that do not satisfy the in-plane uniformity U≤1.5% and their combinations of the opening diameter of the seal and the opening diameter of the SRH. The fields other than the fields in the grayed background show the opening diameter ratios that satisfy the in-plane uniformity U 1.5% and their combinations of the opening diameter of the seal and the opening diameter of the SRH. The respective fields of FIG. 7(A) correspond to the respective fields of FIG. 6(A). The respective fields of FIG. 7(B) correspond to the respective fields of FIG. 6(B). As understood from FIG. 7, the range of the opening diameter ratio that satisfies the in-plane uniformity U 1.5% is preferably [99.32%≤opening diameter ratio R≤99.80%] and is more preferably [99.42% opening diameter ratio R≤99.59%]. Accordingly, the desired in-plane uniformity U≤1.5% is achieved by selecting the opening diameter ϕseal of the seal and the opening diameter ϕsrh of the SRH such that the opening diameter ratio R satisfies the above range.

In a method of manufacturing the plating apparatus 1000 (the plating module 400) provided with the substrate holder 403 configured to hold the substrate, with regard to the process of assembling the seal 421 that has the seal opening 431 and that is configured to seal the outer peripheral part of the substrate and the SRH 422 that has the SRH opening 432 and that is configured to hold the seal 421, a plating film thickness distribution having a desired in-plane uniformity U≤1.5% is achieved by selecting the SRH 422 and the seal 421 such that the size of the opening diameter ϕsrh of the SRH opening 432 is in a range of not lower than 99.32% and not higher than 99.80% (or more preferably in a range of not lower than 99.42% and not higher than 99.59%) of the size of the opening diameter ϕseal of the seal opening 431.

FIG. 10A is a schematic diagram illustrating the configuration of a substrate holder according to a modification. In this modification, a taper 423 that gradually increases the diameter of the opening 432 in a downward direction is provided at an opening edge on a lower side/opening end side (an opposite side to the seal 421 and the substrate 402) of the opening 432 of the SRH 422. The taper 423 is also called opening end-side taper. Providing such a taper 423 facilitates release of bubbles on the surface of the substrate 402 when the substrate holder 403 is exposed to or comes into contact with the plating solution. In this modified configuration, the opening diameter ϕsrh of the SRH referred to as above is a diameter at a narrowest part of the opening 432 of the SRH 422.

FIG. 10B is a schematic diagram illustrating the configuration of a substrate holder according to another modification. In this modification, a taper 424 that gradually increases the diameter of the opening 432 in an upward direction is provided on an upper side (a side close to the seal 421 and the substrate 402) of the SRH 422. The taper 424 is also called seal-side taper. Providing the taper 424 that increases the diameter toward the seal 421-side prevents the plating solution from being accumulated after plating in a step caused by a difference in the opening diameter between the SRH 422 and the seal 421. In this modified configuration, the opening diameter ϕsrh of the SRH referred to as above is a diameter at a narrowest part of the opening 432 of the SRH 422.

FIG. 10C is a schematic diagram illustrating the configuration of a substrate holder according to another modification. In this modification, both the taper 423 and the taper 424 are provided at the SRH 422. This modified configuration has the functions and the advantageous effects of both the two modifications described above. More specifically, this modified configuration facilitates release of bubbles on the surface of the substrate 402 when the substrate holder 403 is exposed to or comes into contact with the plating solution, and prevents the plating solution from being accumulated after plating in a step caused by a difference in the opening diameter between the SRH 422 and the seal 421. In this modified configuration, the opening diameter ϕsrh of the SRH referred to as above is a diameter at a narrowest part of the opening 432 of the SRH 422.

Other Embodiments

In the embodiment described above, the substrate is held in such a manner that the plating surface of the substrate faces down. The above embodiment illustrates the face down-type or cup-type plating module as an example. The configuration of the above embodiment may be applied to a dip-type plating module that performs plating by using a substrate holder configured to hold a substrate in such a manner that a plating surface of the substrate stands up in a vertical direction.

The embodiments described above include at least the following aspects.

According to one aspect, there is provided a substrate holder configured to hold a substrate in an apparatus for plating. The substrate holder comprises a seal configured to seal an outer peripheral part of the substrate and provided with a first opening which a surface to be plated or a plating surface of the substrate is exposed on; and a seal ring holder configured to hold the seal and provided with a second opening which the plating surface of the substrate is exposed on, wherein an opening diameter ratio that is a ratio of an opening diameter of the second opening to an opening diameter of the first opening is in a range of not lower than 99.32% and not higher than 99.80%. In other words, the size of the opening diameter of the second opening is in a range of not lower than 99.32% and not higher than 99.80% of the size of the opening diameter of the first opening. The height of a bank consisting of the seal and the SRH is not shorter than 2.0 mm and not longer than 3.0 mm and is preferably about 2.5 mm. The opening diameter denotes a diameter at a narrowest location in the opening. The opening diameter ratio is a ratio of an opening diameter ϕsrh of the second opening to an opening diameter ϕseal of the first opening expressed as a percentage and is calculated according to Expression (2) given below:

Opening diameter ratio R=ϕsrh/ϕseal×100[%] (2)

The configuration of this aspect controls the opening diameter ratio of the seal ring holder (SRH) to the seal to an appropriate range, so as to achieve a good balance between restriction of the electric field by the SRH and spread of the electric field by the seal and thereby enhance the uniformity in the thickness of a plating film formed on the substrate. Especially this configuration has the effect of suppressing a variation in the thickness of the plating film in the outer peripheral part of the substrate. Furthermore, this configuration enhances the uniformity in the thickness of the plating film formed on the substrate without separately providing a component for adjustment of the electric field on a front face of the SRH.

According to one aspect, in the substrate holder of the above aspect, the opening diameter ratio may be in a range of not lower than 99.42% and not higher than 99.59%.

Further limiting the opening diameter ratio of the SRH to the seal to this range more effectively enhances the uniformity in the thickness of the plating film.

According to one aspect, in the substrate holder of the above aspect, the second opening of the seal ring holder may have a first taper on a side away from the seal, wherein the first taper may be provided to increase a diameter of the second opening in a direction farther away from the seal.

Providing such a first taper facilitates release of bubbles on the surface of the substrate when the substrate holder is exposed to or comes into contact with the plating solution. As a result, this further enhances the in-plane uniformity in the thickness of the plating film.

According to one aspect, in the substrate holder of the above aspect, the second opening of the seal ring holder may have a second taper on a side close to the seal, wherein the second taper may be provided to increase a diameter of the second opening in a direction closer to the seal.

Providing the second taper that increases the diameter toward the seal side prevents the plating solution from being accumulated after plating in a step caused by a difference in the opening diameter between the SRH and the seal. (A) Accumulation of the plating solution in the step increases the amount of the plating solution taken out every time a substrate is to be plated. There is a need to supply the plating solution by an amount corresponding to the taken-out amount of the plating solution. This increases the running cost of the apparatus. (B) Furthermore, accumulation of the plating solution in the step increases the amount of water and a cleaning time required for cleaning the wafer after plating. Increasing the amount of water used for cleaning increases the running cost of the apparatus. Increasing the cleaning time, on the other hand, affects the number of substrates processible per unit time (i.e., the productivity of the apparatus, throughput). Preventing accumulation of the plating solution in the step has the functions and advantageous effects of reducing the running cost of the apparatus and/or improving the throughput.

According to one aspect, in the substrate holder of the above aspect, the second opening of the seal ring holder may have a first taper on a side away from the seal and a second taper on a side close to the seal, wherein the first taper may be provided to increase a diameter of the second opening in a direction farther away from the seal, and the second taper may be provided to increase a diameter of the second opening in a direction closer to the seal.

The configuration of this aspect has both the functions and the advantageous effects given by the first taper described above and the functions and the advantageous effects given by the second taper described above.

The configuration of this aspect has the functions and the advantageous effects given by the first taper described above and/or the functions and the advantageous effects given by the second taper described above.

According to one aspect, the substrate holder described in any of the above aspects may hold the substrate in such a manner that the plating surface of the substrate faces down. The configuration of this aspect has the functions and the advantageous effects described above in a face down-type or cup-type plating apparatus.

According to one aspect, the substrate holder described in any of the above aspects may hold the substrate in such a manner that the plating surface of the substrate stands up. The configuration of this aspect has the functions and the advantageous effects described above in a dip-type plating apparatus that soaks a substrate in a stand-up state in a plating solution to be plated.

According to one aspect, there is provided an apparatus for plating, comprising the substrate holder described in any of the above aspects; and a plating tank which the substrate holder is placed in.

This aspect provides the apparatus for plating that has the functions and the advantageous effects described above.

According to one aspect, there is provided a method of manufacturing an apparatus for plating provided with a substrate holder configured to hold a substrate. The method comprises assembling a seal that is provided with a first opening and that is configured to seal an outer peripheral part of the substrate, and a seal ring holder that is provided with a second opening and that is configured to hold the seal, wherein the assembling the seal and the seal ring holder comprises selecting the seal ring holder and the seal, such that an opening diameter ratio that is a ratio of an opening diameter of the second opening of the seal ring holder to an opening diameter of the first opening of the seal is in a range of not lower than 99.32% and not higher than 99.80%.

The configuration of this aspect controls the opening diameter ratio of the seal ring holder (SRH) to the seal to an appropriate range and thereby enhances the uniformity in the thickness of a plating film formed on the substrate.

Although the embodiments of the present invention have been described based on some examples, the embodiments of the invention described above are presented to facilitate understanding of the present invention, and do not limit the present invention. The present invention can be altered and improved without departing from the subject matter of the present invention, and it is needless to say that the present invention includes equivalents thereof. In addition, it is possible to arbitrarily combine or omit the embodiments and the modifications described above and it is also possible to arbitrarily combine or omit respective constituent elements described in the claims and the specification in a range where at least a part of the above-mentioned problem can be solved or a range where at least a part of the effect is exhibited. The entire disclosure of U.S. Pat. No. 6,193,859 (PTL 1) including the specification, claims, drawings and abstract is incorporated herein by reference in its entirety.

REFERENCE SIGNS LIST

- 100 load port
- 110 transfer robot
- 120 aligner
- 200 pre-wet module
- 300 pre-soak module
- 400 plating module
- 401 plating tank
- 402 substrate
- 403 substrate holder
- 404 plating solution reservoir
- 405 pump
- 406 filter
- 407 plating solution supply tube
- 408 plating solution receiving tank
- 409 power supply
- 410 anode
- 411 motor
- 412 paddle
- 413 drive mechanism
- 413
  a motor
- 413
  b rotation-linear motion conversion mechanism
- 413
  c shaft
- 421 seal
- 422 seal ring holder (SRH)
- 431 seal opening
- 432 SRH opening
- 423 opening end-side taper
- 424 seal-side taper
- 500 cleaning module
- 600 spin rinse dryer
- 700 transfer device
- 800 control module
- 1000 plating apparatus

SUBSTRATE HOLDER, APPARATUS FOR PLATING, AND METHOD OF MANUFACTURING APPARATUS FOR PLATING

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