Plating device

Abstract

The present invention accurately grasps the thickness of a plated film formed on a substrate in a plating device. A plating device is provided with: a plating tank for accommodating a plating solution; a substrate holder for holding a substrate; an anode disposed in the plating bath so as to face the substrate held by the substrate holder; a potential sensor configured so as to be disposed in the vicinity of the substrate held by the substrate holder and to measure the potential of the plating solution; a database for storing reference data of the potential distribution in the vicinity of the substrate, the reference data indicating the potential distribution in the vicinity of the substrate in a predetermined reference state; a potential deviation calculation unit configured to calculate a deviation of the potential distribution measured by the potential sensor with respect to the reference data; and a film thickness calculation unit configured to calculate a deviation of the thickness of the plating film formed on the substrate from the thickness of the plating film in the reference state on the basis of the calculated deviation of the potential distribution.

Description

Technical Field

[0001] The present invention relates to a plating device. Background Art

[0002] The plating device includes a substrate holder for holding a substrate, a plating tank for containing a plating solution, and an anode arranged in the plating tank in a manner opposite to the substrate held by the substrate holder. In the plating device, technical development has been carried out to improve the flatness of the film thickness of the plating formed on the substrate (for example, see Patent Document 1).

[0003] Patent Document 1: Japanese Patent No. 7373684 Summary of the invention

[0004] In a plating apparatus, it is desired to grasp the thickness of a plated film formed on a substrate with higher accuracy.

[0005] [Method 1] According to method 1, a plating device is provided, comprising: a plating tank, the plating tank being used to accommodate a plating solution; a substrate holder, the substrate holder being used to hold a substrate; an anode, the anode being arranged in the plating tank in a manner opposite to the substrate held by the substrate holder; a potential sensor, the potential sensor being configured to be arranged near the substrate held by the substrate holder to measure the potential of the plating solution; a database, the database storing reference data of the distribution of the potential near the substrate, the reference data representing the potential distribution near the substrate under a specified reference state; a potential deviation calculation unit, the potential deviation calculation unit being configured to calculate a deviation of the potential distribution measured by the potential sensor relative to the reference data; and a film thickness calculation unit, the film thickness calculation unit being configured to calculate a deviation of the thickness of a plated film formed on the substrate from the thickness of the plated film under the reference state based on the deviation of the calculated potential distribution.

[0006] [Method 2] According to method 2, based on the plating device of method 1, the above-mentioned benchmark data includes multiple benchmark data corresponding to different values ​​of plating current, and the above-mentioned potential deviation calculation unit is configured to use data obtained by interpolation based on the above-mentioned multiple benchmark data to calculate the above-mentioned deviation of the above-mentioned potential distribution.

[0007] [Mode 3] According to Mode 3, in the plating device of Mode 2, the data obtained by the interpolation corresponds to the value of the plating current when the potential is measured by the potential sensor.

[0008] [Method 4] According to method 4, based on the plating device of method 1, the above-mentioned reference data includes a plurality of reference data corresponding to the micro-processing pattern on the above-mentioned substrate, and the above-mentioned potential deviation calculation unit is configured to calculate the above-mentioned deviation of the above-mentioned potential distribution using the reference data corresponding to the above-mentioned micro-processing pattern of the substrate in the plating treatment which is the object of potential measurement based on the above-mentioned potential sensor among the above-mentioned plurality of reference data.

[0009] [Mode 5] According to Mode 5, based on the plating device of Mode 1, the above-mentioned prescribed reference state is at least a state in which poor power supply does not occur between the above-mentioned substrate and the above-mentioned substrate holder.

[0010] [Mode 6] According to Mode 6, in the plating device of Mode 1, the predetermined reference state corresponds to a state in which a plated film is formed with a flatness higher than a predetermined threshold value.

[0011] [Mode 7] According to Mode 7, the plating device of Mode 1 is further provided with a plating processing control unit, and the plating processing control unit is configured to perform control corresponding to the deviation of the plating film thickness calculated by the film thickness calculation unit.

[0012] [Method 8] According to method 8, based on the plating device of method 7, the above-mentioned control includes: (i) notification of an alarm, (ii) control of the rotation of the above-mentioned substrate holder, (iii) position control of a shielding body for locally shielding the plating current in the above-mentioned plating solution, and (iv) control of at least one of stirring of the above-mentioned plating solution.

[0013] [Method 9] According to method 9, on the basis of the plating device of method 1, it is further equipped with: a state-space model, wherein the state-space model is configured to use a state equation and an observation equation to infer the current density flowing at the outer edge of the substrate, the state equation is an equation describing the time development related to the current density flowing at the outer edge of the substrate, and the observation equation is an equation describing the relationship between the current density flowing at the outer edge of the substrate and the potential of the plating solution at the position of the potential sensor; and a current density calculation unit, wherein the current density calculation unit is configured to calculate the plating current density at an area of ​​the substrate that is inner than the outer edge based on the current density inferred by the state-space model, and the plating device is configured such that the output from the potential deviation calculation unit is input into the state-space model, and the output from the current density calculation unit is input into the film thickness calculation unit.

[0014] [Method 10] According to method 10, on the basis of the plating device of method 9, there is a plating module, the plating module at least includes the plating tank, the substrate support, the anode and the potential sensor, and the relationship between the current density and the potential of the plating solution is based on a function representing a 3D model of the plating module.

[0015] [Method 11] According to method 11, based on the plating device of method 9, the state-space model further has a Kalman filter, and the Kalman filter is configured to correct the inferred result of the current density flowing at the outer edge of the substrate based on the measurement value of the potential sensor.

[0016] [Mode 12] According to Mode 12, based on the plating device of Mode 9, the outer edge portion of the substrate is a portion of the substrate held by the substrate holder. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a perspective view showing the overall structure of the plating apparatus according to the present embodiment.

[0018] Figure 2 It is a plan view showing the overall structure of the plating apparatus according to the present embodiment.

[0019] Figure 3 It is a longitudinal sectional view schematically showing the structure of a plating module according to one embodiment.

[0020] Figure 4 is from Figure 3 Top view observed from the IV-IV direction.

[0021] Figure 5 This is a schematic diagram of the shielding body and the substrate viewed from below.

[0022] Figure 6 It is a block diagram showing the functional structure of a control module according to one embodiment.

[0023] Figure 7 is a top view of the substrate.

[0024] Figure 8 It is a block diagram showing the functional structure of a control module according to another embodiment.

[0025] Fig. 9 This is a diagram conceptually showing the processing performed by the potential deviation calculation unit.

[0026] Fig.10 FIG. 1 is a diagram showing an exemplary database storing a plurality of reference data.

[0027] Fig.11 This is a diagram for explaining interpolation of reference data. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings described below, the same or corresponding components are denoted by the same reference numerals and duplicate descriptions are omitted.

[0029] <First embodiment>

[0030] Figure 1 It is a perspective view showing the overall structure of the plating apparatus according to the present embodiment. Figure 2 2 is a top view showing the overall structure of the plating device of this embodiment. Figure 1 , Figure 2 As shown, the plating device 1000 includes: a loading port 100, a conveying robot 110, an aligner 120, a pre-wetting module 200, a pre-preg module 300, a plating module 400, a cleaning module 500, a spin dryer 600, a conveying device 700 and a control module 800.

[0031] The loading port 100 is a module for carrying a substrate stored in a box such as a FOUP (not shown) into the plating device 1000, or carrying a substrate out of the plating device 1000 to a box. In the present embodiment, four loading ports 100 are arranged in a horizontal direction, but the number and arrangement of the loading ports 100 are arbitrary. The conveying robot 110 is a robot for conveying substrates, and is configured to transfer substrates between the loading port 100, the aligner 120, and the conveying device 700. When transferring substrates between the conveying robot 110 and the conveying device 700, the conveying robot 110 and the conveying device 700 can transfer substrates via a temporary stage (not shown).

[0032] The aligner 120 is a module for aligning the orientation plane, notch and other positions of the substrate in a specified direction. In the present embodiment, two aligners 120 are arranged in a horizontal direction, but the number and configuration of the aligners 120 are arbitrary. The pre-wet module 200 replaces the air inside the pattern formed on the surface of the substrate with the treatment liquid by wetting the plated surface of the substrate before the plating process with a treatment liquid such as pure water or degassed water. The pre-wet module 200 is configured to implement a pre-wet process, which is a process of easily supplying the plating liquid to the inside of the pattern by replacing the treatment liquid inside the pattern with the plating liquid during plating. In the present embodiment, two pre-wet modules 200 are arranged in a vertical direction, but the number and configuration of the pre-wet modules 200 are arbitrary.

[0033] The prepreg module 300 is configured to implement a prepreg treatment, which is a treatment for cleaning or activating the surface of the plated substrate by etching away the oxide film with high resistance such as the surface of the seed layer formed on the plated surface of the substrate before the plating treatment with a treatment solution such as sulfuric acid or hydrochloric acid. In the present embodiment, two prepreg modules 300 are arranged in the up-down direction, but the number and configuration of the prepreg modules 300 are arbitrary. The plating module 400 implements a plating treatment on the substrate. In the present embodiment, there are two groups of 12 plating modules 400, which are arranged in the up-down direction with 3 units and arranged in the horizontal direction with 4 units, and a total of 24 plating modules 400 are provided, but the number and configuration of the plating modules 400 are arbitrary.

[0034] The cleaning module 500 is configured to perform cleaning on the substrate in order to remove the plating liquid etc. remaining in the substrate after the plating treatment. In the present embodiment, two cleaning modules 500 are arranged in the vertical direction, but the number and configuration of the cleaning modules 500 are arbitrary. The spin dryer 600 is a module for rotating the substrate after the cleaning treatment at high speed for drying. In the present embodiment, two spin dryers are arranged in the vertical direction, but the number and configuration of the spin dryers are arbitrary. The conveying device 700 is a device for conveying substrates between multiple modules in the plating device 1000. The control module 800 is configured to control multiple modules of the plating device 1000, and can be composed of a common computer or a special computer having an input and output interface with an operator, for example.

[0035] An example of a series of plating processes performed by the plating device 1000 is described. First, a substrate stored in a box is carried into the loading port 100. Next, the conveying robot 110 takes out the substrate from the box of the loading port 100 and conveys the substrate to the aligner 120. The aligner 120 aligns the orientation plane, notch, etc. of the substrate in a predetermined direction. The conveying robot 110 delivers the substrate aligned by the aligner 120 to the conveying device 700.

[0036] The conveying device 700 conveys the substrate received from the conveying robot 110 to the pre-wetting module 200. The pre-wetting module 200 performs a pre-wetting process on the substrate. The conveying device 700 conveys the substrate subjected to the pre-wetting process to the pre-preg module 300. The pre-preg module 300 performs a pre-preg process on the substrate. The conveying device 700 conveys the substrate subjected to the pre-preg process to the plating module 400. The plating module 400 performs a plating process on the substrate.

[0037] The conveying device 700 conveys the substrate subjected to the plating process to the cleaning module 500. The cleaning module 500 performs a cleaning process on the substrate. The conveying device 700 conveys the substrate subjected to the cleaning process to the spin dryer 600. The spin dryer 600 performs a drying process on the substrate. The conveying device 700 delivers the substrate subjected to the drying process to the conveying robot 110. The conveying robot 110 conveys the substrate received from the conveying device 700 to the box of the loading port 100. Finally, the box containing the substrate is unloaded from the loading port 100.

[0038] also, Figure 1 , Figure 2 The structure of the plating device 1000 described in the above is merely an example, and the structure of the plating device 1000 is not limited to Figure 1 , Figure 2 structure.

[0039] Next, the structure of the plating module 400 will be described. Since the 24 plating modules 400 of this embodiment have the same structure, only one plating module 400 will be described. Figure 3 1 is a longitudinal sectional view schematically showing the structure of a plating module 400 according to an embodiment. The plating module 400 is provided with a plating tank for accommodating a plating solution. The plating tank is configured to include a cylindrical inner tank 412 with an opening on the upper surface, and an outer tank (not shown) provided around the inner tank 412 in a manner to store the plating solution overflowing from the upper edge of the inner tank 412.

[0040] The plating module 400 includes a substrate holder 440, which is used to hold the substrate Wf in a state where the plated surface Wf-a is facing downward. The substrate holder 440 includes a power supply contact for supplying power to the substrate Wf from a power supply not shown in the figure. The plating module 400 further includes a lifting mechanism 442 for lifting and lowering the substrate holder 440. In addition, in one embodiment, the plating module 400 includes a rotating mechanism 448 for rotating the substrate holder 440 around a vertical axis. The substrate holder 440 can be rotated in a positive direction (e.g., clockwise) and a reverse direction (e.g., counterclockwise) by the rotating mechanism 448, and the rotation speed can also be changed. Such rotation of the substrate holder 440 is controlled by the control module 800. In addition, the lifting mechanism 442 and the rotating mechanism 448 can be implemented by a known mechanism such as a motor.

[0041] The plating module 400 includes a diaphragm 420 that separates the interior of the inner tank 412 in the vertical direction. The interior of the inner tank 412 is divided into a cathode region 422 and an anode region 424 by the diaphragm 420. Plating liquid is filled in the cathode region 422 and the anode region 424, respectively. In addition, in the present embodiment, an example of providing the diaphragm 420 is shown, but the diaphragm 420 may not be provided.

[0042] An anode 430 is provided on the bottom surface of the inner groove 412 of the anode region 424. In addition, an anode shield 426 for adjusting the electric field between the anode 430 and the substrate Wf is arranged in the anode region 424. The anode shield 426 is a substantially plate-shaped member made of a dielectric material, for example, and is provided in front of the anode 430 (at the Figure 3 The anode shield 426 has an opening for the current flowing between the anode 430 and the substrate Wf to pass through. The anode shield 426 can also be configured to be able to change the opening size, and the opening size is adjusted by the control module 800. The opening size means the diameter when the opening is circular, and means the length of one side or the longest opening width when the opening is polygonal. The change of the opening size of the anode shield 426 can adopt a known mechanism. In this embodiment, an example of setting the anode shield 426 is shown, but the anode shield 426 may not be set. In addition, the above-mentioned diaphragm 420 may also be set at the opening of the anode shield 426.

[0043] In the cathode region 422, a resistor 450 is arranged in a manner opposite to the diaphragm 420. The resistor 450 is a component for achieving uniform plating treatment of the plated surface Wf-a of the substrate Wf. In one embodiment, the resistor 450 is configured to be movable in the vertical direction in the plating tank by a driving mechanism 452, and the position of the resistor 450 is adjusted by the control module 800. However, the plating module 400 may not have the resistor 450. The specific material of the resistor 450 is not particularly limited, and as an example, a porous resin such as polyetheretherketone can be used.

[0044] A paddle not shown in the figure is provided near the surface of the substrate Wf in the cathode region 422 for stirring the plating solution. The paddle is made of, for example, titanium (Ti) or resin. The paddle stirs the plating solution by reciprocating in parallel with the surface of the substrate Wf so that sufficient metal ions are uniformly supplied to the surface of the substrate Wf during the plating of the substrate Wf. The paddle may also be configured to move perpendicularly to the surface of the substrate Wf. The movement of the paddle is controlled by the control module 800 through a drive mechanism not shown in the figure. In addition, the plating module 400 may not have a paddle.

[0045] In addition, a potential sensor 470 is provided in the cathode region 422. When the cathode region 422 is provided with a resistor 450, the potential sensor 470 can be provided between the substrate Wf and the resistor 450. The potential sensor 470 is supported by a sensor support 468. In addition, the potential sensor 470 can also be supported by the side wall of the inner tank 412 or the resistor 450 instead of the sensor support 468. In addition, the sensor support 468 can also be a paddle for stirring the plating solution. Here, the paddle preferably moves parallel to the plate surface of the substrate Wf to stir the plating solution, but is not limited to such an example. In the present embodiment, a plurality of potential sensors 470 are provided along the radial direction of the substrate Wf. However, it is not limited to such an example, as long as at least one potential sensor 470 is provided in the plating module 400.

[0046] Figure 4 is from Figure 3 The top view observed from the IV-IV direction. Figure 3 and Figure 4 As shown, the potential sensor 470 is arranged at a first position in the area between the substrate Wf and the anode 430. That is, the potential sensor 470 is located between the substrate Wf and the anode 430 in a direction perpendicular to the plate surface of the substrate Wf, and is arranged at a position overlapping with the substrate Wf when viewed from a direction perpendicular to the plate surface of the substrate Wf. The potential sensor 470 is preferably arranged close to the plated surface Wf-a. As an example, the distance between the potential sensor 470 and the plated surface Wf-a is hundreds of micrometers, several millimeters, or tens of millimeters. The potential sensor 470 detects the potential of the arrangement location (first position) between the substrate Wf and the anode 430.

[0047] A second potential sensor 472a and a third potential sensor 472b may also be provided in the plating tank 410. The second potential sensor 472a and the third potential sensor 472b are disposed at a location in the plating tank 410 where there is no relative potential change. Specifically, the second potential sensor 472a and the third potential sensor 472b are disposed at a second position and a third position outside the region between the substrate Wf and the anode 430. That is, Figure 4 As shown in FIG. 1 , when viewed from a direction perpendicular to the plate surface of the substrate Wf, the second potential sensor 472a and the third potential sensor 472b are arranged at positions that do not overlap with the substrate Wf. The second potential sensor 472a and the third potential sensor 472b detect the potential of the arrangement location (second position, third position) away from the substrate Wf and the anode 430. The second and third potential sensors 472a and 472b are supported by sensor support bodies 469a and 469b. In addition, the second and third potential sensors 472a and 472b may also be supported by the side wall of the inner groove 412 or the resistor 450 instead of the sensor support bodies 469a and 469b.

[0048] As an example, the potential sensor 470, the second potential sensor 472a, and the third potential sensor 472b can be formed of electrodes of the same material and / or the same shape. As the electrode material, at least one of platinum (Pt), gold (Au), carbon (C), and copper (Cu) can be used.

[0049] The detection signals of the potential sensor 470, the second potential sensor 472a, and the third potential sensor 472b are input to the control module 800. The control module 800 can infer the thickness of the plated film formed on the substrate Wf based on the detection value of the potential of the potential sensor 470 or the detection signals of the potential sensor 470, the second potential sensor 472a, and the third potential sensor 472b. As an example, the control module 800 can infer the distribution of the plating current in the substrate surface during the plating process based on the detection signal from the potential sensor 470, and infer the film thickness distribution of the plated film on the substrate based on the inferred distribution of the plating current.

[0050] In addition, the control module 800 may detect the end point of the plating process based on the detection value of the potential sensor 470, and may also predict the time until the end point of the plating process. As an example, the control module 800 may also end the plating process when the film thickness of the plated film inferred based on the detection value of the potential sensor 470 becomes a desired thickness. In addition, as an example, the control module 800 may also calculate the film thickness increase rate based on the film thickness of the plated film inferred based on the detection value of the potential sensor 470, and based on the obtained film thickness increase rate, predict the time until the plated film becomes the desired thickness, that is, the time until the end point of the plating process.

[0051] return Figure 3 In one embodiment, a shielding body 480 is provided in the cathode region 422. The shielding body 480 is used to partially or partially shield the current flowing from the anode 430 to the substrate Wf. The shielding body 480 is, for example, a substantially plate-shaped member made of a dielectric material. Figure 5 This is a schematic diagram of the shielding body 480 and the substrate Wf according to this embodiment as viewed from below. Figure 5 In the figure, the substrate holder 440 holding the substrate Wf is omitted. The shielding body 480 is configured to be able to shield the surface Wf-a between the substrate Wf and the anode 430 (at the shielding position). Figure 3 and Figure 5 , the position shown by the dotted line), and the retreat position (at the retreat position between the plated surface Wf-a and the anode 430) Figure 3 and Figure 5In other words, the shielding body 480 is configured to be movable to a shielding position below the plated surface Wf-a and a retreat position away from below the plated surface Wf-a. The position of the shielding body 480 is controlled by the control module 800 via a drive mechanism not shown in the figure. The movement of the shielding body 480 can be achieved by a known mechanism such as a motor or a solenoid. Figure 3 and Figure 5 In the example shown, the shielding body 480 shields a portion of the circumferential direction of the outer peripheral area of ​​the plated surface Wf-a of the substrate Wf at the shielding position. Figure 5 In the example shown, the shielding body 480 is formed in a tapered shape that becomes thinner toward the center of the substrate Wf. However, the present invention is not limited to this example, and the shielding body 480 can use any shape predetermined by experiments or the like.

[0052] The plating process of the plating module 400 is described. The lifting mechanism 442 is used to immerse the substrate Wf in the plating solution of the cathode region 422, thereby exposing the substrate Wf to the plating solution. In this state, the plating module 400 applies a voltage between the anode 430 and the substrate Wf, thereby being able to perform a plating process on the plated surface Wf-a of the substrate Wf. In addition, in one embodiment, the plating process is performed while the substrate holder 440 is rotated using a rotating mechanism 448. Through the plating process, a conductive film (plating film) is deposited on the plated surface Wf-a of the substrate Wf. During the plating process, the potential sensor 470 measures the potential. By performing a measurement based on the potential sensor 470 accompanied by the rotation of the substrate holder 440 (substrate Wf), the measurement position of the potential sensor 470 can be changed, and the potential can be measured at multiple locations on the circumference of the substrate Wf, or throughout the entire circumference. Then, the control module 800 infers the film thickness of the plated film based on the detected value of the potential of the potential sensor 470. Thereby, changes in the film thickness of the plated film formed on the plated surface Wf-a of the substrate Wf can be grasped in real time during the plating process.

[0053] Figure 61 is a block diagram showing the functional structure of a control module 800 in an embodiment of a plating device 1000. The control module 800 is configured to use a state space model 804 to infer the distribution of the current density flowing through the substrate Wf during the plating process. The state space model 804 includes a state inference unit 806, an observation value calculation unit 808, and a Kalman filter 810. In addition to the state space model 804, the control module 800 also includes a 3D model making unit 802, a current density calculation unit 812, a film thickness calculation unit 814, and an endpoint determination unit 816. The control module 800 can be configured as a computer having an input / output device, a computing device, a storage device, etc. For example, the control module 800 is configured to read and execute a computer program stored in a storage device by a computing device (such as a processor) to realize the functions of each unit 802, 806, 808, 810, 812, 814, 816.

[0054] The 3D model making unit 802 makes a three-dimensional (3D) model of the plating module 400. The 3D model of the plating module 400 is data that describes the shapes, configurations, physical properties, etc. of the various components in the plating module 400 by modeling. The 3D model is at least loaded with components that affect the electric field inside the plating tank (inner tank 412) of the plating module 400. Such components include, for example, an anode 430, an anode shield 426, a diaphragm 420, a resistor 450, a substrate Wf, a seed layer disposed on the substrate Wf, a plating solution and a potential sensor 470 contained in the plating tank. The 3D model of the plating module 400 can be composed of information about the shapes, configurations, and physical properties (e.g., conductivity, dielectric constant, etc.) of the above-mentioned components. As an example, the information can be input to the control module 800 by the operator of the plating device 1000 via the input / output interface of the control module 800, and the 3D model making unit 802 can make a 3D model of the plating module 400 based on the input information. A part of the above information, such as some physical property values, can be pre-stored in the storage device of the control module 800, and the operator can also select appropriate values ​​therefrom.

[0055] The state estimation unit 806 is configured to estimate the “state” of the plating module 400 using the state equation. Specifically, the state estimation unit 806 estimates the current density of the plating current in the outer edge portion of the substrate Wf as the “state” of the plating module 400 .

[0056] Figure 7 FIG. 4 is a top view of the substrate Wf. The outer edge portion 62 of the substrate Wf is a portion of the substrate Wf held by the substrate holder 440 and is not exposed to the plating solution. Figure 7 As shown, the substrate Wf has one or more electrical contacts 441 at the outer edge portion 62. Figure 7In the example, the substrate Wf has six electric contacts 441 at equal intervals on the outer edge portion 62. The electric contact 441 is connected to the negative terminal of the power supply (not shown) via an electrical wiring (not shown) built into the substrate holder 440, and the plating current flows to the substrate Wf through the electric contact 441.

[0057] Hereinafter, the current density of the plating current in the outer edge portion 62 of the substrate Wf is referred to as “outer edge portion current density”, and the outer edge portion current density at time t is described as j t (θ). Here, θ represents the angle around the center of the substrate Wf (refer to Figure 7 Here, the outer edge current density j is expressed by the Fourier series as follows: t (θ).

[0058] [Formula 1]

[0059]

[0060] Current density at outer edge j t The inference of (θ) is regressed to the Fourier coefficient a i,t and b i,t In one embodiment, the state estimation unit 806 uses the following state equation to estimate the outer edge current density j at time t-1. t-1 (θ) Estimated (predicted) outer edge current density j at time t t (θ).

[0061] [Formula 2]

[0062]

[0063] The matrix Fi is given by the following equation, which represents the rotation of the substrate Wf using the rotation mechanism 448. In addition, the vector v t is noise. In this model, it is assumed that the outer edge current density at time t is obtained by rotating the outer edge current density at time t-1 along with the rotation of the substrate Wf. In addition, in the following formula, ω is the angular velocity of the rotation of the substrate Wf, and Δt is the time step (i.e., the time difference between time t and time t-1).

[0064] [Formula 3]

[0065]

[0066] Furthermore, in order to estimate the outer edge current density, a state equation different from the above equation may be used.

[0067] The observation value calculation unit 808 is configured to use the observation equation and estimate the "observation value" from the "state" of the plating module 400. Specifically, the observation value calculation unit 808 calculates the "observation value" based on the outer edge current density j t (θ) Estimate (calculate) the value of the potential of the plating solution in the plating tank measured by the potential sensor 470 as the "observation value" in the plating module 400. Hereinafter, the value calculated by the observation value calculation unit 808 is referred to as the "potential estimation value", and the potential estimation value at time t is described as φ t .

[0068] As described above, the potential measured by the potential sensor 470 is the potential near the plated surface Wf-a of the substrate Wf subjected to the plating process. This potential is determined by the distribution of the plating current flowing from the plating solution in the plating tank to the substrate Wf. Moreover, the distribution of the plating current depends on the physical structure of the plating module 400. Therefore, the potential estimation value φ t The potential estimated value φ can be calculated using the 3D model of the plating module 400 created by the 3D model creation unit 802. t It can be expressed as follows.

[0069] [Formula 4]

[0070] φ t =F(a 1，t ,b 1，t , …) (5)

[0071] Here, F is a function representing the 3D model of the plating module 400, a i，t , b i，t etc. is the above-mentioned outer edge current density j t (θ) is the Fourier coefficient. In addition, the function F can be numerically determined based on the 3D model obtained from the 3D model creation unit 802. Further, as follows, around a i，t = 0 and b i，t =0 Taylor expansion is performed on the function F of the above formula. The following formula is an approximate formula up to the first-order term, but second-order or higher-order terms may also be considered.

[0072] [Formula 5]

[0073]

[0074] In one embodiment, the observation value calculation unit 808 uses the following observation equation: t (θ) Calculate the estimated potential value φ at time t t . Where w t It's noise.

[0075] [Formula 6]

[0076]

[0077] This observation equation is based on the Taylor expansion of the function F representing the 3D model of the plating module 400 as described above. In addition, in order to obtain the potential estimation value φ t , or a different observation equation can be used.

[0078] The Kalman filter 810 is configured to use the actual measurement results in the plating module 400 to correct the "state" of the plating module 400 inferred by the state inference unit 806. Specifically, the Kalman filter 810 uses the actual potential measurement value obtained from the potential sensor 470 for correction. In one embodiment, the Kalman filter 810 calculates the potential inference value φ calculated by the observation value calculation unit 808 based on the potential measurement value obtained from the potential sensor 470. t The difference between the outer edge current density j estimated by the state estimation unit 806 t (θ)(i.e. Fourier coefficient a i，t and b i，t ) for correction.

[0079] Furthermore, as described above, the substrate Wf is rotated by the rotating mechanism 448, so the potential sensor 470 can obtain the measured values ​​of the potential at multiple measurement points along the circumferential direction of the substrate Wf. Therefore, by performing correction using the measured values ​​at these multiple measurement points, the accurate outer edge current density can be obtained.

[0080] The outer edge current density j estimated and corrected using the state space model 804 is t (θ) is output to the current density calculation unit 812. The current density calculation unit 812 calculates the region 64 (see FIG. 1 ) inside the outer edge 62 of the substrate Wf based on the outer edge current density obtained from the state space model 804. Figure 7 ) in the plating solution. Region 64 is different from the outer edge 62 of the substrate Wf and is not held by the substrate holder 440, but is exposed to the plating solution. The current flows into region 64 from the plating solution in the plating tank. That is, the current density calculation unit 812 calculates the current density of the current flowing from the plating solution in the plating tank into the substrate Wf via the interface between the plating solution and the substrate Wf. The thickness of the plated film formed on the substrate Wf depends on the current density. Hereinafter, this current density is referred to as the "plating current density", and the plating current density at position k and time t on the substrate Wf (region 64) is described as j k，t .

[0081] Plating current density j k，t and the outer edge current density j t(θ) is related to each other in a specific relationship. Specifically, the plating current density is determined by the outer edge current density and the physical structure of the plating module 400. Therefore, it is related to the above-mentioned potential estimation value φ t Similarly, the plating current density j k，t The 3D model of the plating module 400 can be expressed as shown below.

[0082] [Formula 7]

[0083] j k,t =G k (a 1，t , b 1，t , …) (9)

[0084] Here, G k is a function representing the 3D model of the plating module 400, a i，t , b i，t is the outer edge current density j t Fourier coefficients of (θ). Function G k It can be determined numerically based on the 3D model of the plating module 400 obtained from the 3D model creation unit 802. i，t = 0 and b i，t =0 for the function G of the above formula k Taylor expansion is performed. The following formula is an approximate formula up to the first-order term, but second-order and higher-order terms can also be considered.

[0085] [Formula 8]

[0086]

[0087] In one embodiment, the current density calculation unit 812 can calculate the plating current density j using the above formula: k，t .

[0088] The film thickness calculation unit 814 is configured to calculate the thickness of the coating based on the plating current density j obtained from the current density calculation unit 812. k，t , calculate the film thickness of the plating formed on the substrate Wf. In one embodiment, the film thickness calculation unit 814 calculates the film forming speed v of the plating at the position k and time t on the substrate Wf using the following formula: k，t and film thickness w k，t .

[0089] [Formula 9]

[0090]

[0091] Wherein, M and ρ are the molecular weight and density of the plating deposited on the substrate Wf, z is the valence of the plating reaction, and F is the Faraday constant. The film thickness calculation unit 814 can also use the state equation described above to predict the future plating current density and film forming speed, thereby calculating the film thickness w at the end time of the plating process (time t = T). k，T Instead of the current film thickness w k，t .

[0092] The end point determination unit 816 determines the end point of the plating process on the substrate Wf based on the plated film thickness obtained by the film thickness calculation unit 814. For example, the end point determination unit 816 may determine the end point of the plating process on the substrate Wf based on the estimated current film thickness w k，t When the desired thickness is reached, the plating process is terminated, or the current film thickness w estimated may be used. k，t and the predicted future film forming rate v k，s (s=t, ..., T), and the time until the end point of the plating process is predicted.

[0093] As described above, according to the plating device 1000 of this embodiment, by using the state space model, the film thickness of the plated film can be estimated based on the measurement value of the potential sensor 470. Thus, the film thickness change of the plated film formed on the plated surface Wf-a of the substrate Wf can be grasped in real time during the plating process.

[0094] <Second embodiment>

[0095] Figure 8 4 is a block diagram showing the functional structure of the control module 801 of another embodiment. The control module 801 of this embodiment is configured to calculate the deviation of the film thickness distribution of the plated film formed on the substrate Wf from the reference state based on the deviation of the potential distribution measured by the potential sensor 470 from the predetermined reference state. For example, when the electric contact 441 (refer to Figure 7 ) and the substrate holder 440, when the substrate Wf is plated in a non-ideal state such as poor power supply between some of the substrate holders 440 and the substrate Wf, the signal indicating the potential distribution near the substrate obtained from the potential sensor 470 sometimes shows unevenness (concave and / or convexity) caused by poor power supply, etc. On the other hand, when a substrate Wf having a micro-processing pattern on the plated surface Wf-a is the object of plating, even if the plating is performed in an ideal state, unevenness corresponding to the micro-processing pattern sometimes appears in the potential distribution signal from the potential sensor 470. Therefore, as described in detail below, according to the control module 801 of this embodiment, by using the difference between the potential distribution obtained from the potential sensor 470 and the potential distribution in the ideal state (reference state), it is possible to calculate the deviation of the film thickness distribution actually formed on the substrate Wf from the film thickness distribution obtained when the plating is performed in the ideal state.

[0096] The plating device 1000 may also replace the first embodiment ( Figure 6 ) or, based on the control module 800, having a control module 801 of the present embodiment.

[0097] like Figure 8 As shown, the control module 801 includes: a 3D model making unit 802, a state space model 804, a current density calculation unit 812, a film thickness calculation unit 814, a database 818, a potential deviation calculation unit 820 and a plating treatment control unit 822. The state space model 804 includes a state inference unit 806, an observation value calculation unit 808 and a Kalman filter 810. The 3D model making unit 802, the state space model 804, the state inference unit 806, the observation value calculation unit 808, the Kalman filter 810, the current density calculation unit 812 and the film thickness calculation unit 814 in the control module 801 are the same as the corresponding parts in the control module 800 of the first embodiment described above. Similar to the control module 800, the control module 801 can be configured as a computer having an input / output device, a computing device, a storage device, etc. For example, the control module 801 is configured to realize the functions of each unit 802 , 806 , 808 , 810 , 812 , 814 , 820 , and 822 by reading and executing a computer program stored in a storage device through a computing device (eg, a processor).

[0098] The database 818 stores reference data of the potential distribution near the substrate Wf. The reference data is data indicating the potential distribution near the substrate Wf under a specified reference state. In the present specification, "specified reference state" means a state in which the substrate Wf can be plated ideally. For example, the specified reference state may be a state in which there is no poor power supply between the electrical contact 441 on the substrate Wf and the substrate holder 440, or more generally, it may be a state in which the various parts of the plating module 400 are appropriately set in such a way that a plated film can be formed on the substrate Wf with a certain degree of flatness. The reference data of the potential distribution near the substrate under such a reference state can be obtained by plating the substrate Wf in advance under the reference state, and then using the potential sensor 470 to measure the potential near the substrate Wf, and can be stored in the database 818 in advance.

[0099] The potential distribution of the reference data may be, for example, the distribution of the potential near the substrate along the circumference of the substrate Wf. As described above, the substrate Wf is rotated by the rotating mechanism 448 while the plating process is performed, thereby obtaining the measured values ​​of the potential at multiple locations in the circumference of the substrate Wf (or throughout the entire circumference) from the potential sensor 470. A series of potential measurement values ​​obtained in the reference state in this way can be stored in the database 818 as reference data representing the potential distribution along the circumference of the substrate Wf. In addition, the potential distribution near the substrate Wf depends on the size of the plating current, the micro-processing pattern formed or present on the plated surface Wf-a of the substrate Wf, etc. Therefore, the reference data for each of these various conditions can be stored in the database 818 in advance.

[0100] The potential deviation calculation unit 820 is configured to calculate a deviation of the potential distribution measured by the potential sensor 470 with respect to the reference data. Fig. 9 8 is a diagram conceptually showing the processing performed by the potential deviation calculation unit 820. Fig. 9 In each of the graphs, the horizontal axis represents the position (angle) of the substrate Wf in the circumferential direction (see Figure 7 ), the vertical axis represents the potential. Fig. 9 The graph 901 in FIG. 4 shows an example of a potential distribution measured by the potential sensor 470. The potential distribution includes a peak 904 caused by poor power supply between the electric contact 441 on the substrate Wf and the substrate holder 440, and peaks 905 and 906 caused by the micro-processing pattern on the plated surface Wf-a of the substrate Wf. Fig. 9 The graph 902 in FIG. 9 shows an example of reference data. As described above, the reference data is a potential distribution in a reference state, so the potential distribution in the graph 902 includes peaks 905 and 906 corresponding to the microfabrication pattern, but does not include a peak corresponding to a power supply failure. Fig. 9 Graph 903 in FIG. 8 represents the deviation of the potential distribution calculated by the potential deviation calculation unit 820, which is obtained by subtracting the potential distribution (reference data) of graph 902 from the potential distribution (the potential distribution measured by the potential sensor 470) of graph 901. As a result of the subtraction, graph 903 has only a peak 904 corresponding to the power supply failure.

[0101] In addition, the reference data may be biased so that the average levels of the two may be consistent before the potential distribution of the graph 902 is subtracted from the potential distribution of the graph 901. Fig.10As shown, multiple reference data corresponding to multiple plating current values ​​and multiple micro-processing patterns are stored, and the potential deviation calculation unit 820 can select the reference data corresponding to the currently implemented plating process from the database 818, and use the reference data for calculating the deviation of the potential distribution. In addition, the potential deviation calculation unit 820 can also interpolate the reference data stored in the database 818 to generate reference data corresponding to the current plating current, and use it for calculating the deviation of the potential distribution. For example, Fig.11 As shown, the potential deviation calculation unit 820 can generate reference data corresponding to a plating current of 4 amperes not stored in the database 818 by interpolation using reference data corresponding to a plating current of 3 amperes and reference data corresponding to a plating current of 5 amperes.

[0102] As described above, in the control module 801 of the present embodiment, the potential deviation calculation unit 820 is used to calculate the deviation (i.e., the potential distribution) of the potential generated by the plating process under non-ideal conditions (e.g., poor power supply). Fig. 9 903 in the figure). The deviation of the potential distribution calculated by the potential deviation calculation unit 820 is input to the state-space model 804. The state-space model 804, the current density calculation unit 812 and the film thickness calculation unit 814 in the control module 801 of the present embodiment are configured to be the same as the corresponding units in the control module 800 of the first embodiment described above, so that the film thickness (distribution) corresponding to the deviation of the potential distribution calculated by the potential deviation calculation unit 820 is output from the film thickness calculation unit 814, that is, the deviation (distribution) of the film thickness formed on the substrate Wf in the current plating process from the film thickness formed on the substrate Wf in the reference state. That is, the film thickness calculation unit 814 in the control module 801 of the present embodiment can calculate the deviation (distribution) of the film thickness formed on the substrate Wf caused by the plating process under non-ideal conditions (for example, a state of poor power supply). Thereby, the film thickness of the plating formed on the substrate Wf can be grasped with high precision, and in addition, it can be easily determined whether the plating process is performed under ideal conditions in the plating device 1000.

[0103] The plating process control unit 822 is configured to perform control corresponding to the deviation of the plated film thickness calculated by the film thickness calculation unit 814. For example, when the deviation of the film thickness calculated by the film thickness calculation unit 814 is greater than a predetermined threshold value, the plating process control unit 822 may notify an alarm to the operator of the plating device 1000 by voice, text, image, sound, light, etc. In addition, the plating process control unit 822 may also control the rotating mechanism 448 in a manner of changing or adjusting the direction and rotation speed of the substrate holder 440 according to the size of the deviation of the film thickness calculated by the film thickness calculation unit 814. In addition, the plating process control unit 822 may also control the switching of the position of the shielding body 480 between the shielding position and the retreat position, and control the presence or absence of stirring the plating solution by a paddle or the stirring intensity according to the distribution of the deviation of the film thickness calculated by the film thickness calculation unit 814. Through these controls, the flatness of the plated film formed on the substrate Wf can be improved.

[0104] The embodiments of the present invention are described above based on several examples, but the embodiments of the invention described above are intended to facilitate the understanding of the present invention and do not limit the present invention. The present invention can be changed and improved without departing from its main purpose, and the present invention also includes its equivalents. In addition, within the scope of at least a part of the above-mentioned problem that can be solved or within the scope of at least a part of the effect, any combination or omission of the constituent elements recorded in the claims and the specification can be performed.

[0105] Description of Reference Numerals

[0106] 1000…plating device; 100…loading port; 110…transport robot; 120…aligner; 200…prewetting module; 300…prepreg module; 400…plating module; 500…cleaning module; 600…spin dryer; 700…transport device; 800…control module; 412…inner tank; 420…diaphragm; 422…cathode region; 424…anode region; 426…anode mask; 430…anode; 440…substrate support; 441…electrical contact; 442…lifting mechanism; 448…rotating mechanism; 450…resistor; 452…driving mechanism; 468…sensor support; 470…potential sensor; 480…shielding body; 801…control module; 802…3D model making unit; 804…state space model; 806…state inference unit; 808…observation value calculation unit; 810…Kalman filter; 812…current density calculation unit; 814…film thickness calculation unit; 816…end point determination unit; 818…database; 820…potential deviation calculation unit; 822…plating treatment control unit; 62…outer edge portion.

Claims

1. A plating device, characterized in that: have: A plating tank, the plating tank is used to contain a plating solution; A substrate support, the substrate support is used to hold the substrate; an anode, the anode being arranged in the plating tank so as to face the substrate held by the substrate holder; a potential sensor configured to be arranged near the substrate held by the substrate holder and to measure the potential of the plating solution; a database storing reference data of the potential distribution near the substrate, the reference data indicating the potential distribution near the substrate under a predetermined reference state; a potential deviation calculation unit configured to calculate a deviation of the potential distribution measured by the potential sensor with respect to the reference data; as well as A film thickness calculation unit is configured to calculate a deviation of a plated film thickness formed on the substrate from a plated film thickness in the reference state based on the calculated deviation of the potential distribution.

2. The plating device according to claim 1, characterized in that: The reference data includes a plurality of reference data corresponding to different plating current values, The potential deviation calculation unit is configured to calculate the deviation of the potential distribution using data obtained by interpolation based on the plurality of reference data.

3. The plating device according to claim 2, characterized in that: The interpolated data corresponds to the value of the plating current when the potential is measured by the potential sensor.

4. The plating device according to claim 1, characterized in that: The reference data includes a plurality of reference data corresponding to the microfabrication pattern on the substrate, The potential deviation calculation unit is configured to calculate the deviation of the potential distribution using reference data corresponding to the fine-fabrication pattern of the substrate being plated and being the target of potential measurement by the potential sensor, among the plurality of reference data.

5. The plating device according to any one of claims 1 to 4, characterized in that: The predetermined reference state is at least a state in which power supply failure does not occur between the substrate and the substrate holder.

6. The plating device according to any one of claims 1 to 4, characterized in that: The predetermined reference state corresponds to a state in which the plated film is formed with a flatness higher than a predetermined threshold value.

7. The plating device according to any one of claims 1 to 4, characterized in that: The present invention further includes a plating process control unit configured to perform control according to a deviation of the plated film thickness calculated by the film thickness calculation unit.

8. The plating device according to claim 7, characterized in that: The control includes at least one of (i) notification of an alarm, (ii) control of rotation of the substrate holder, (iii) position control of a shielding body for partially shielding a plating current in the plating solution, and (iv) control of stirring of the plating solution.

9. The plating device according to any one of claims 1 to 4, characterized in that: Further possesses: a state-space model configured to infer a current density flowing at an outer edge of the substrate using a state equation and an observation equation, wherein the state equation is an equation describing a time evolution associated with the current density flowing at the outer edge of the substrate, and the observation equation is an equation describing a relationship between the current density flowing at the outer edge of the substrate and a potential of the plating solution at a position of the potential sensor; and a current density calculation unit configured to calculate a plating current density at a region of the substrate that is inside the outer edge portion based on the current density estimated by the state-space model, The plating apparatus is configured such that the output from the potential deviation calculation unit is input to the state-space model, and the output from the current density calculation unit is input to the film thickness calculation unit.

10. The plating device according to claim 9, characterized in that: A plating module is provided, wherein the plating module at least includes the plating tank, the substrate support, the anode and the potential sensor, The relationship between the current density and the potential of the plating solution is based on a function representing a 3D model of the plating module.

11. The plating device according to claim 9, characterized in that: The state-space model further includes a Kalman filter configured to correct an estimation result of the current density flowing in the outer edge portion of the substrate based on a measurement value of the potential sensor.

12. The plating device according to claim 9, characterized in that: The outer edge portion of the substrate is a portion of the substrate held by the substrate holder.

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