KR20230104711A - Sputtering device, sputtering device control method, and sputtering device control device - Google Patents

Abstract

A sputtering apparatus according to one aspect of the present invention includes one or more targets disposed facing a substrate and made of a film-forming material, one or more magnet units disposed on the back surface of the targets, positions of each of the magnet units, and the magnet units. Setting conditions including at least one of each movement pattern and an inflow current or an inflow current variation pattern of an electromagnet constituting each of the magnet units, and a film quality measurement value of the film-forming material on the substrate just formed by the sputtering device a control device having an optimal solution calculation unit that calculates an optimal solution of the set condition for at least one of the magnet units based on input information including at least a, and individually adjusting the set condition of the magnet unit based on the optimal solution. It is provided with an adjustment unit capable of doing so.

Description

Sputtering device, sputtering device control method, and sputtering device control device

The present invention relates to a sputtering device having one or more cathodes in which one or more magnet units are disposed on the rear surface of a target, a control method thereof, and a control device for the sputtering device.

A magnetron sputtering apparatus in which one or more magnet units are arranged on the back surface (non-sputtering surface) of a target is known as a film forming apparatus for a large-area substrate. The film deposition homogeneity (e.g., film thickness or sheet resistance) on the surface of a substrate formed in a magnetron sputtering device is an important performance factor for the substrate, and maintaining the homogeneity is a very important function required of a sputtering device. am.

In the magnetron sputtering device, the higher the horizontal magnetic flux density (magnetic flux density perpendicular to the electric field) of the target surface (sputtering surface), the higher the erosion rate of the target surface by plasma, and accordingly, more film-forming material from the target surface Since is released, high-speed film formation on the substrate surface becomes possible. Typically, the higher the horizontal magnetic flux density is in a region on the target surface, the higher the rate of film deposition to the surface region of the substrate facing the region tends to be relatively higher than that of other surface regions.

Therefore, in the case of forming a film on a large substrate using a magnetron sputtering device, the distribution of the horizontal magnetic field density has a great influence on the homogeneity of the film quality within the surface of the substrate. In order to form a film with a homogeneous film quality, it is necessary to appropriately set the position or movement pattern of the magnet unit and the magnetic strength or magnetic strength variation pattern.

As a method of achieving homogenization of the film quality by setting the position or movement pattern of the magnet unit, a technique of reciprocating the magnet unit along the back surface of the target (for example, see Patent Document 1), or a magnet unit relative to the back surface of the target A technique for moving in the direction of close spacing is known (for example, refer to Patent Literature 2). Further, Patent Document 3 includes a cylindrical target and a plurality of magnet units arranged therein, and rotates the surface of the target in the circumferential direction to scan a region where a magnetic field is formed along the circumferential direction from the surface of the target. A cathode is disclosed.

Japanese Unexamined Patent Publication No. 2000-239841 Japanese Unexamined Patent Publication No. 2020-200525 Japanese Unexamined Patent Publication No. 2016-113646

Since the shape of the target surface changes along with the progress of erosion, the distribution of film quality also changes with time. Therefore, in order to maintain the homogeneity of the film quality, it is necessary to continuously set the optimal position or movement pattern of the magnet unit and magnetic strength or magnetic strength variation pattern with the passage of time.

However, since the progress speed of erosion is affected by various factors such as pressure, applied voltage, sputtering gas flow rate, target constituent material, and quality difference between targets, it is difficult to accurately predict the progress of erosion. In addition, since the erosion proceeds faster in the area where the horizontal magnetic flux density is higher, the difference between the progress of the prediction and the actual erosion accelerates with the passage of time.

Therefore, it is difficult to set in advance the optimal position or movement pattern of the magnet unit and the magnetic force intensity or magnetic force intensity variation pattern as a function of time. It is necessary to regularly carry out a series of operations to adjust the position or movement pattern and the magnetic strength or magnetic strength variation pattern. Execution of the operation is one of the causes of a decrease in the operating rate of the device, and this problem is significantly more likely to occur as the size of the substrate increases.

Also, in general, individual differences cannot be avoided even among industrial products produced with the same design. Therefore, in the case of installing a plurality of sputtering devices, there may occur a case in which equal distribution of film quality cannot be obtained even if all recognizable film formation conditions are unified. In such a case, it is necessary to tune the position or movement pattern of the magnet unit for each device and the magnetic strength or change pattern of the magnetic force intensity, which is one of the problems to be solved during device operation.

In view of the above circumstances, an object of the present invention is to provide a sputtering device, a control method thereof, and a control device for a sputtering device capable of improving film deposition homogeneity and device operation rate.

A sputtering device according to one aspect of the present invention,

at least one target made of a film-forming material disposed facing the substrate;

one or more magnet units disposed on the rear surface of the target;

setting conditions including at least one of a position of each of the magnet units, a movement pattern of each of the magnet units, and an inflow current or an inflow current variation pattern of an electromagnet constituting each of the magnet units; a control device having an optimum solution calculation unit that calculates an optimum solution of the set condition for at least one of the magnet units based on input information including at least a film quality measurement value of a film forming material on the substrate;

and an adjustment unit capable of individually adjusting the setting conditions of the magnet unit based on the optimal solution.

The sputtering device is connected to a device for measuring the film quality of the film forming material on the substrate, and can automatically acquire the measured value, calculate the optimal solution, and adjust the setting conditions based on the optimal solution.

The target may be a planar target provided to a planar cathode or the like or a cylindrical target provided to a rotary cathode. One or a plurality of magnet units may correspond to one target.

The position of the magnet unit indicates a relative positional relationship between a target corresponding to the magnet unit and the magnet unit. That is, for a flat target, the relative position of the magnet unit with respect to an arbitrary reference plane parallel to the target is indicated. For a cylindrical target, the relative position of the magnet unit with respect to the central axis of rotation of the target is indicated.

The movement pattern of the magnet unit indicates a pattern of temporal change of the position of the magnet unit when film formation of one substrate is performed while changing the position of the magnet unit.

The incoming current of the magnet unit represents a current flowing through a coil to generate magnetic force when some or all of the magnets constituting the magnet unit are electromagnets.

The inflow current variation pattern of the magnet unit represents a pattern of time change before the inflow of the magnet unit when forming a film on one substrate while varying the inflow current of the magnet unit.

The film quality includes at least one of physical property values representing characteristics of a film formed in the sputtering device. Physical property values representing the properties of the film are, for example, film thickness, sheet resistance, light transmittance, film stress, refractive index, etching characteristics, and film density.

The measured film quality of the film forming material on the substrate includes measurement data regarding the film quality of the film forming material at a plurality of measuring points on the substrate.

The input information may further include information on one or more factors that may affect the distribution of membrane quality. The factors that can affect the distribution of the film quality are, for example, the type of film forming material, the surface shape of the target, the voltage applied to the target, the discharge time, the type of sputtering gas, and the pressure during film formation. .

The optimal solution calculating unit determines the position of each of the magnet units, the movement pattern of each of the magnet units, the inflow current of the electromagnets constituting each of the magnet units, based on the input information, that can satisfy a predetermined management value of the membrane distribution. It is configured to calculate an optimal solution for at least one of inflow current variation patterns of electromagnets constituting each of the magnet units.

As a method for calculating the optimum solution, for example, a machine learner that learns actual film formation results, a simulation using a mathematical model, and a degenerate model obtained by reconstructing a part of the mathematical model with a large computational load with a machine learner can be used, for example. do.

In addition, the machine learner, the mathematical model, or the degenerate model that directly outputs the optimal solution may be used, and the machine learner, the mathematical model, or the degenerate model that outputs the predicted film quality distribution for any candidate for the optimal solution , a mathematical optimization program for searching for a candidate of the optimal solution in which the predicted film quality distribution is optimal may be used.

A method for controlling a sputtering device according to one aspect of the present invention is a control method for a sputtering device having at least one target made of a film-forming material and disposed facing a substrate, and at least one magnet unit disposed on the back surface of the target, comprising:

setting conditions including at least one of a position of each of the magnet units, a movement pattern of each of the magnet units, and an inflow current or an inflow current variation pattern of an electromagnet constituting each of the magnet units; Calculating an optimal solution of the set condition for at least one of the magnet units based on input information including at least a film quality measurement value of a film forming material on the substrate;

Based on the optimal solution, the setting conditions of the magnet unit are individually adjusted.

A control device for a sputtering device according to one aspect of the present invention controls a sputtering device including at least one target made of a film-forming material and disposed facing a substrate, and at least one magnet unit disposed on the back surface of the target. As a device,

setting conditions including at least one of a position of each of the magnet units, a movement pattern of each of the magnet units, and an inflow current or an inflow current variation pattern of an electromagnet constituting each of the magnet units; and an optimal solution calculation unit that calculates an optimal solution of the set condition for at least one of the magnet units based on input information including at least a film quality measurement value of a film forming material on the substrate.

ADVANTAGE OF THE INVENTION According to this invention, the improvement of film-attaching homogeneity and an operating rate of an apparatus can be aimed at.

1 is a schematic cross-sectional view of a sputtering device according to an embodiment of the present invention.
Fig. 2 is an enlarged view explaining one configuration example of a magnet unit in the sputtering device.
Fig. 3 is a schematic diagram explaining the relationship between the relative position of the magnet unit with respect to the target and the film quality homogeneity.
Fig. 4 is a schematic diagram explaining the suppression of the temporal change of the membrane distribution by adjusting the fluctuation of the magnet unit.
5 is a front view showing an arrangement of magnet units.
Fig. 6 is a schematic configuration diagram of an adjustment unit in the sputtering apparatus.
Fig. 7 is a block diagram showing the configuration of a control device in the sputtering device.
Fig. 8 is a flowchart showing an example of a processing procedure executed in the control device shown in Fig. 7;
9 is a schematic cross-sectional view of a sputtering device according to another embodiment of the present invention.
Fig. 10 is a schematic configuration diagram of a rotary cathode in the sputtering device shown in Fig. 9;
Fig. 11 is a schematic diagram explaining the suppression of the temporal change of the membrane distribution by adjusting the fluctuation of the magnet unit.
Fig. 12 is a schematic diagram explaining the relationship between the rocking position of the magnet unit relative to the target and the homogeneity of the film quality.
Fig. 13 is a block diagram showing the configuration of a control device in the sputtering device shown in Fig. 9;
Fig. 14 is a flowchart showing an example of a processing procedure executed in the control device shown in Fig. 13;
Fig. 15 is a schematic diagram of a main part explaining a structural modification of the sputtering device shown in Fig. 1;

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described, referring drawings.

<First Embodiment>

[Basic configuration of sputtering device]

1 is a schematic cross-sectional view of a sputtering device 100 according to an embodiment of the present invention. In Fig. 1, the X-axis, Y-axis, and Z-axis indicate three axial directions orthogonal to each other, and the Z-axis corresponds to the vertical direction (height direction).

The sputtering device 100 is a magnetron sputtering device, and includes a vacuum chamber 1, a substrate holder 2, a target 3, a backing plate 4, a plurality of magnet units 5, and an anti-chacking plate ( 6) is provided. The sputtering device 100 may be a single-wafer type vertical sputtering device or an inline type vertical sputtering device. In addition, when the size of the substrate is smaller than a predetermined size, the sputtering device 100 may be a horizontal type sputtering device.

The vacuum chamber 1 is connected to a vacuum pump 7, and is configured to be capable of evacuating or maintaining a predetermined reduced pressure atmosphere therein. The substrate holder 2 is disposed inside the vacuum chamber 1 and supports the substrate W in a vertical position. The vacuum chamber 1 and the substrate holder 2 are typically connected to ground potential. The substrate W is, for example, a rectangular glass substrate with a width of 1850 mm or more and a length of 1500 mm or more.

Although not shown, the vacuum chamber 1 is provided with a loading port of the substrate holder 2 and an exit port thereof. The inlet and outlet may be common or separate. The inlet and outlet are configured to be opened and closed through gate valves not shown in the drawings.

The target 3 is made of a film forming material for forming a film on the substrate W. Typical examples of the film-forming material include metals, alloys, metal oxides, metal nitrides, and synthetic resins. In this embodiment, a metal or alloy target having conductivity is used.

The target 3 may be an ingot target or a sinter target. Although the number, size, arrangement, etc. of the targets 3 are not particularly limited, in the present embodiment, the targets 3 are constituted by a single rectangular plate material having a larger area than the substrate W, and the vacuum chamber 1 Inside, they are disposed facing the substrate W at a predetermined distance (TS distance) in the X-axis direction.

The backing plate 4 is a metal plate that supports the rear surface of the target 3 and is fixed to the vacuum chamber 1 via an insulating member 11 . The backing plate 4 is typically bonded to the target 3 via a brazing material such as indium. The backing plate 4 is connected to a power supply 8 having an RF power source or a direct current power source installed outside the vacuum chamber 1 .

The plurality of magnet units 5 are disposed facing the back surface (non-sputtering surface) of the target 3 via the backing plate 4 . The plurality of magnet units 5 constitute a magnetic circuit that forms a magnetic field on the surface (sputtering surface) of the target 3 .

2 is an enlarged view of the magnet unit 5 . The magnet unit 5 has a first magnet 51 , a second magnet 52 , and a yoke 53 supporting the first magnet 51 and the second magnet 52 . The end of the first magnet 51 on the target 3 side and the end of the second magnet 52 on the target 3 side are magnetized so as to have opposite magnetic poles. The shape, arrangement, etc. of the first magnet 51 and the second magnet 52 are not particularly limited, but in this embodiment, the first magnet 51 is formed in a straight shape extending in the Z-axis direction, The second magnet 52 is formed in a rectangular annular shape so as to surround the periphery of the first magnet 51 . The shape or number of the first and second magnets 51 and 52 constituting the magnetic circuit is not limited to this example and can be arbitrarily set.

The anti-chacking plate 6 is disposed between the substrate holder 2 and the target 3, and the sputtering material (film forming material) flying from the target 3 is applied to the inner surface of the side wall of the vacuum chamber 1 or the substrate W. A plasma space P for generating plasma is defined between the target 3 and the substrate holder 2 while preventing adhesion to the outer peripheral region (periphery of the substrate holder 2). The vacuum chamber 1 is equipped with a gas introduction line 9 for introducing a sputtering gas such as Ar (argon) from a gas source 9s into the plasma space P.

When forming a film on the substrate W by the sputtering device 100, the sputtering gas is introduced into the plasma space P from the gas introduction line 9, and the backing plate 4 from the power supply source 4 As RF power or DC power is input to the target 3 through , magnetron discharge occurs in the plasma space P. A plurality of magnet units 5 arranged on the back surface of the target 3 form a magnetic field orthogonal to the electric field on the surface of the target 3, confining electrons in the plasma to the vicinity of the surface of the target 3. As a result, the electron density increases even with a small sputtering power, and the amount of ion rushing into the target increases.

In the magnetron sputtering device, the higher the horizontal magnetic flux density (magnetic flux density perpendicular to the electric field) of the target surface (sputtering surface), the higher the erosion rate of the target surface by plasma, and accordingly, more film-forming material is sputtered from the target surface Because of this, high-speed film formation on the substrate surface becomes possible. Typically, the higher the magnetic flux density of the horizontal magnetic field B of each magnet unit 5 is in the area on the surface of the target 3, the film deposition speed to the surface area of the substrate W opposite to the area is different. It tends to be relatively higher than the surface area. For this reason, in order to make the film quality distribution on the substrate W uniform, it is necessary to strictly control the magnetic flux density distribution of the horizontal magnetic field B on the surface of the target 3 .

[Explanation of how film distribution can be adjusted by adjusting the position of the magnet unit in the X-axis direction]

For example, when the position of the magnet unit in the X-axis direction is fixed, the distance from the target surface to the magnet unit gradually decreases along with the progress of erosion on the target surface, and as a result, the horizontal magnetic flux on the target surface density increases. In addition, as shown in Fig. 3 (A) and (B), since the erosion 3e advances faster in the area where the horizontal magnetic flux density is higher in the target surface, the horizontal magnetic flux on the surface of the target 3 The difference in density appears more markedly with the lapse of time. For this reason, as the number of processed sheets increases, the uniformity of deposition on the furnace of the substrate W tends to deteriorate.

Therefore, as shown in FIG. 3(C), in order to lower the horizontal magnetic flux density in the surface area of the target 3 where the traveling speed of the erosion 3e is high, the magnet unit 5 constituting the magnetic circuit is If it is made to move in the direction away from the surface of the target 3, the acceleration-like increase of the horizontal magnetic flux density in the said area|region can be suppressed, and the film deposition amount can be homogenized.

In addition, when some or all of the first magnet 51 and the second magnet 52 constituting the magnetic circuit are electromagnets, not only the position adjustment of the magnet unit 5 in the X-axis direction, but also the first magnet 51 Also, by adjusting the magnitude or direction of the inflow current of the coil constituting the second magnet 52, the horizontal magnetic flux density in the surface area of the target 3 can be adjusted, and the film deposition amount can be homogenized.

[Explanation of how the film distribution can be adjusted by adjusting the Y-axis fluctuation of the magnet unit]

Since the use efficiency of the target is low in a state in which only a limited area of the target 3 is eroded, a technique for eroding a wider range by swinging the magnet unit 5 in the Y-axis direction is known (see Patent Document 1 ).

In general, since the erosion by a single magnet unit 5 swinging in the Y-axis direction at a constant speed has the fastest center of swing, the surface shape of the target becomes an air (bowl) shape. 4(A) and (B) show changes in the surface shape of the target 3 after a predetermined time elapses from the start of sputtering of the target 3, and the Y-axis of the magnet unit 5 relative to the target 3 The time change of the position of each direction is shown. Since the speed at which the distance between the surface of the target 3 and the magnet unit 5 approaches is fast in the central part of the air on the surface of the target 3, as shown in Fig. 4(B), the erosion central part 3e- The difference in the progress speed between the center) and the erosion both sides (3e-side) becomes more remarkable with the passage of time.

Therefore, when the rocking is continued at a constant speed, the balance of the traveling speed of the erosion center part (3e-center) and the erosion side part (3e-side) changes, and as the erosion progresses, the difference in these speeds becomes more remarkable As a result, a change in film quality distribution occurs, and at the same time, target use efficiency is reduced.

So, as shown in FIG. 4(C), in order to maintain the balance of the traveling speed between the erosion center portion (3e-center) and the erosion both side portions (3e-side), the magnet unit 5 is erosion both side portions 3e -side), by lengthening the swing distance in the Y-axis direction of the magnet unit 5, and/or by slowing down the moving speed at both ends of the swing, the change in membrane distribution is suppressed, , it is possible to maintain a homogeneous membrane quality. Specifically, lengthening the time for the magnet unit 5 to stay around the end of the swing (see countermeasure example 1 in FIG. 4(C)), providing a time for the magnet unit 5 to stop at the end of the swing ( Methods such as increasing the swing width of the magnet unit 5 (see countermeasure example 3), or arbitrarily combining these countermeasure examples 1 to 3 can be adopted.

In addition, when some or all of the first magnet 51 and the second magnet 52 constituting the magnetic circuit are electromagnets, the first magnet 51 and the second magnet 51 change according to the position during the swing of the magnet unit 5 By adjusting the current flowing in the coil constituting the two magnets 52 (hereinafter referred to as inflow current fluctuation pattern), there is an effect similar to that of adjusting the movement pattern of the magnet unit 5 in the Y-axis direction. Specifically, the change in membrane distribution can be suppressed by increasing the current when the magnet unit 5 is near the end of the swing and decreasing the current when the magnet unit 5 is around the center of the swing.

As described above, as a setting condition of the magnet unit 5, it is to change the position of the magnet unit 5 in the X-axis direction, the movement pattern in the Y-axis direction, and the inflow current or inflow current fluctuation pattern with the passage of time. It is important to maintain membrane quality homogeneity.

However, since the progress speed of erosion is affected by various factors such as pressure, applied voltage, sputtering gas flow rate, target constituent material, target quality, etc., it is difficult to accurately predict the progress of erosion. In addition, since the erosion proceeds faster in the area where the horizontal magnetic flux density is higher, the difference between the progress of the erosion between the reality and the prediction accelerates with the passage of time.

Therefore, it is difficult to preset the position of the optimum magnet unit in the X-axis direction, the movement pattern in the Y-axis direction, and the inflow front* or inflow current fluctuation pattern as a function of time. , It is necessary to stop the device and periodically perform a series of operations to adjust the position of the magnet unit in the X-axis direction, the movement pattern in the Y-axis direction, and the inflow current or inflow current fluctuation pattern. Execution of the operation has become one of the causes of a decrease in the operating rate of the device, and this problem tends to occur remarkably as the size of the substrate increases.

Then, in this embodiment, the sputtering apparatus 100 is comprised as follows in order to aim at the improvement of film deposition homogeneity and an apparatus operation rate.

[Details of sputtering device]

(magnet unit)

Fig. 5 is a front view of the arrangement of the plurality of magnet units 5, viewed from the X-axis direction. In the example shown in the figure, each magnet unit 5 has a first block 5a long in the height direction (Z-axis direction), and a pair of second blocks disposed at both ends of the first block 5a. It is constituted by a block 5b, and the first and second magnets 51 and 52 shown in FIG. 2 are disposed on each of these blocks 5a and 5b. A plurality of magnet units 5 including a first block 5a and a pair of second blocks 5b are arranged in a transverse direction (Y-axis direction) (nine sets in the illustrated example). For this reason, the magnetic circuit arranged on the back surface of the target 3 is divided into 27 pieces in total.

In each magnet unit 5, the length of the first block 5a along the Z-axis direction is formed to be longer than that of the second block 5b, but is not limited to this, and each block 5a, 5b is the same It can also be formed in length. The number of blocks constituting each magnet unit 5 is not limited to three, but may be two or four or more. The number of arrays of magnet units 5 is not limited to 9, but may be less or more than this. That is, the number of divisions of magnetic circuits composed of a plurality of magnet units 5 or the size of the divided magnetic circuits is not limited to the illustrated example, and the size and deposition amount of the target 3 or substrate W must be adjusted. It can be arbitrarily set according to the position on the substrate W to be targeted, the in-plane distribution of the deposition amount on the target substrate W, and the like.

The sputtering device 100 includes an adjustment unit 10 capable of individually adjusting the relative distance of the first and second blocks 5a and 5b of each magnet unit 5 to the target 3, and the adjustment unit 10 It is further provided with a control device 20 for controlling.

(adjustment unit)

6 is a plan view showing a schematic configuration of the adjustment unit 10 as viewed in the Z-axis direction. The adjustment unit 10 is disposed outside the vacuum chamber 1 and has a plurality of driving units 11 disposed corresponding to the first and second blocks 5a and 5b of each magnet unit 5 . Each drive unit 11 is composed of a drive cylinder or a drive motor having drive shafts 11a and 11b, one end of which is connected to the first and second blocks 5a and 5b, for example. The drive shaft 11a moves the first and second blocks 5a and 5b in the direction of approaching or separating from the target 3 by expanding and contracting in the X-axis direction. The drive shaft 11b moves the first and second blocks 5a and 5b in a direction parallel to the target 3 by expanding and contracting in the Y-axis direction.

Further, when some or all of the magnets constituting each magnet unit 5 are electromagnets, the adjustment unit 10 may include a device for adjusting the current flowing through each electromagnet. The device for adjusting the current flowing through the electromagnet may be adjusted so that a constant current always flows, or may be adjusted so that the incoming current changes in association with the fluctuation of the magnet unit 5 in the Y-axis direction.

The adjustment unit 10 allows an operator to manually adjust the position of each magnet unit 5 in the X-axis direction, the movement pattern in the Y-axis direction, and the inflow current or inflow current variation pattern. Based on a control command from the control device 20, the position in the X-axis direction, the movement pattern in the Y-axis direction, and the inflow current or inflow current variation pattern may be automatically adjusted.

(control device)

The control device 20 is composed of a computer including a CPU (Central Processing Unit), an internal memory, an input/output interface, and the like. In this embodiment, the controller 20 controls the operation of the entire sputtering device 100 including the adjustment unit 10, the vacuum pump 7, the power supply source 8, and the gas introduction line 9.

7 is a block diagram showing the configuration of parts according to the present invention among the functions of the control device 20. The control device 20 has an input unit 21, an optimal solution calculation unit 22, and an output unit 23.

The input unit 21 has a function of obtaining, from the sputtering device 100, measurement values of various film formation conditions when each substrate is formed and film quality formed on each substrate. In addition, when the quality of the film formed on each substrate is measured by a measuring device different from the sputtering device 100, the control device 20 is connected to the measuring device, and an input unit 21 is provided on each substrate. It also has a function of acquiring the measured value of the film quality just formed on the surface.

Various film formation conditions when the substrate is formed are the setting conditions of each magnet unit 5, the position of each magnet unit 5 in the X-axis direction, the movement pattern in the Y-axis direction, and before inflow* or inflow. In addition to necessarily including any one or more of the current fluctuation patterns, the type of film forming material constituting the target 3, the consumption amount of the target 3 (the surface shape of the target 3), and the application to the target 3 voltage (input voltage from power supply 8), flow rate of sputtering gas, pressure in the chamber, and the like.

The measured value of the film quality formed on each of the substrates is the measured value of the film quality at the measuring points at a plurality of specific positions on the substrate W. The arrangement of the measurement points is not particularly limited, but from the viewpoint of managing the distribution of the film quality formed on each substrate, the measurement point is widely distributed on the substrate W or the maximum or minimum film quality within the plane of the substrate W is determined. It is desirable that the position to be included. These measuring points may be predetermined before film formation starts, or may be arbitrarily determined after film formation.

The optimal solution calculation unit 22 calculates the magnet unit 5 based on the set conditions and input information including at least the measured value of the film quality of the film forming material on the substrate W formed by the sputtering device 100. ) Calculate an optimal solution (or optimal value) of the setting condition for at least one of ).

The optimal solution calculation unit 22 calculates, on the basis of various types of input information obtained by the input unit 21, the optimal position in the X-axis direction of each magnet unit 5 at which the homogeneity of the film quality is obtained, the movement pattern in the Y-axis direction, and the inflow current Alternatively, it has a function of calculating the inflow current variation pattern. Details of the optimal solution calculation unit 22 will be described below.

The optimal solution calculation unit 22 in this embodiment is constituted by a prediction unit 221, a correction unit 222, and an optimization unit 223.

The prediction unit 221 calculates a homogeneity prediction value of the membrane quality for each of the predetermined magnet units. The prediction unit 221 is a function that takes various film formation conditions as arguments and returns a film quality prediction value when it is assumed that film formation is performed under those conditions. The method for calculating the predicted value of the film quality is not particularly limited, and in the present embodiment, a machine learner that learns the relationship between various film formation conditions and film quality in advance is used.

The algorithm of the machine learner is not particularly limited, and for example, any one of neutral linear regression, neural network, decision tree, and support vector machine, or an ensemble learning model combining a plurality of them is applicable.

It is essential that the argument of the prediction unit 221 includes the position of each magnet unit 5 in the X-axis direction, the movement pattern in the Y-axis direction, and the inflow current or inflow current variation pattern. In addition, film formation conditions that affect the film quality distribution, such as, for example, the type of film formation material, the surface shape of the target, the voltage applied to the target, the discharge time, the type of sputtering gas and the pressure during film formation, are additionally acquired. By including in , it is possible to construct a machine learning machine with higher precision.

The estimated value of the film quality, which is the return value of the prediction unit 221, is the predicted value of the film quality at all measurement points on the actual substrate W. The reason for the measurement point being the same as that of the actual substrate W is that it needs to be compared with the actual film quality measurement value acquired by the input unit 21.

By inputting actual film formation conditions as arguments of the prediction unit 221, it is possible to calculate a predicted film quality value in actual film formation. However, the film quality is the position of each magnet unit 5 in the X-axis direction, the movement pattern in the Y-axis direction, the inflow current or inflow current fluctuation pattern, pressure, applied voltage, sputtering gas inflow amount, target constituent material, difference in target quality, etc. Since it is affected by various factors and it is difficult to measure all of these factors, it is rare that predicted values of film quality in actual film formation coincide with measured values.

Therefore, it is necessary to correct the predicted film quality in order to match the actual film-formed film quality predicted value with the measured value. The correcting unit 222 compares the predicted value of the film quality and the measured value in the actual film formation, and calculates the correction parameter and corrects the predicted value of the film quality. If the accuracy of the prediction by the predictor 221 is sufficiently high, the effect of the correction is small, so the method of correction by the corrector 222 may be a simple addition or multiplication.

By correcting the predicted film quality value calculated by the predictor 221 by the correction unit 222, it becomes possible to predict the film quality under arbitrary film formation conditions. Hereinafter, the predicted value of film quality corrected by the correction unit 222 will be described as a corrected predicted value of film quality.

The optimization unit 223 searches for film formation conditions in which a corrected predicted value of an optimal film quality is obtained. In this embodiment, the position in the X-axis direction of each magnet unit 5, the movement pattern in the Y-axis direction, and the inflow current or inflow current fluctuation pattern such that the statistic representing the homogeneity of the predicted value of the film quality corrected is minimized. Search using an optimization algorithm. As the statistic representing the homogeneity of the corrected predicted value of the film quality, a homogeneity index (Max-Min)/(Max+Min) or a coefficient of variation generally used in the sputtering field is used. As the mathematical optimization algorithm, for example, a gradient descent method, grid search, brute force method, Bayesian optimization, etc. can be used.

According to the present embodiment, in order to obtain the optimum film quality homogeneity for actual recent film formation, the position of each magnet unit 5 in the X-axis direction, the movement pattern in the Y-axis direction, and the inflow current or inflow current variation pattern Information on how should be set (optimal film formation conditions) can be obtained. Since the erosion of the target 3 progresses in a time span of several days to several weeks, the time from the latest film formation to the completion of the calculation of the optimum film formation conditions is If it is short enough with respect to the advancing speed of the erosion, it is considered that the optimum film formation condition is an effective film formation condition even at the point of completion of calculation.

The output unit 23 transmits the position of each magnet unit 5 in the X-axis direction, the movement pattern in the Y-axis direction, and the inflow current or inflow current variation pattern of each magnet unit 5 calculated by the optimal solution calculation unit 22 to the adjustment unit 10. and make adjustments.

For each actual film formation data, by automatically using the control device 20, the position in the X-axis direction of each magnet unit 5, the movement pattern in the Y-axis direction, and the inflow current before the homogeneity of the film quality is greatly damaged. Alternatively, it becomes possible to adjust the inflow current fluctuation pattern and maintain the homogeneity of the film quality.

In addition, by referring to the actual film formation result when calculating the optimal solution, it is possible not only to respond to changes over time, but also to automatically absorb individual differences existing among a plurality of devices, and to each device. It becomes possible to perform optimum adjustment for

Fig. 8 is a flowchart showing one example of the processing procedure executed in the control device 20 of the present embodiment.

The input unit 21 acquires input information (step 101). The input information includes various film formation conditions when each substrate is formed and measured values of film quality formed on each substrate.

Subsequently, the optimum solution calculation unit 22 (prediction unit 221) calculates a film quality homogeneity prediction value of the film forming material on the substrate W based on the input information obtained by the input unit 21, and based on the calculated prediction value , it is determined whether or not the homogeneity of the film quality is within the target range (steps 102 and 103).

Subsequently, the optimal solution calculation unit 22 (calibration unit 222) compares the measured value of the film quality obtained from the input unit 21 and the predicted value calculated from the prediction unit 221 when the homogeneity of the film quality is not within the target range and a correction coefficient for correcting the predicted value is determined (steps 104 and 105).

Subsequently, the optimal solution calculation unit 22 (optimization unit 223) can satisfy the target film quality homogeneity for setting conditions such as the position of each magnet unit 5 at which the corrected membrane quality prediction value is optimal. An optimal solution that exists is searched for (step 106).

Subsequently, the output unit 23 individually calculates the amount of adjustment to the optimal solution of each current magnet unit 5 based on the optimal solution calculated by the optimal solution calculation unit 22, Output (step 107). Alternatively, the output unit 23 generates a control command based on the calculated optimal solution for each magnet unit 5, outputs the control command to the adjustment unit 10, and determines the setting conditions for each magnet unit 5. Set to the above optimal solution.

As described above, according to the present embodiment, the film quality homogeneity of the material formed on the substrate W is within a predetermined target range based on input information such as setting conditions of each magnet unit 5 and actual measured values. It can be determined whether there is In addition, the optimal solution calculating section 22 can calculate an optimal solution for the set conditions of each magnet unit 5, based on this information, to obtain film quality homogeneity.

In the conventional sputtering apparatus (comparative example), the film quality homogeneity on the formed substrate W is periodically evaluated, and if the evaluation result is within the target range (below the control value), the process is continued as it is, and the evaluation result is the target If it is outside the range (exceeding the control value), operation of the device is stopped, and position adjustment of each magnet unit 5 is performed manually. For this reason, since it is necessary to stop the device every time the magnet unit 5 is adjusted, a decrease in the operating rate of the device has been a problem. In addition, since skill level is required for the positioning operation of each magnet unit 5, there is a limit to the improvement of the operation rate of the device. In addition, since a control value cannot be strictly set in order to suppress a decrease in the equipment operating rate, stable homogeneity of the film quality within a lot or between lots has been difficult to obtain.

On the other hand, according to the present embodiment, since the position of each magnet unit 5 can be automatically adjusted without stopping the operation of the sputtering device 100, it is possible to significantly improve the operating rate of the device. In addition, since the homogeneity is evaluated based on the calculated value of the film quality by the progress of the sputtering process, the position of the magnet unit 5 can be adjusted before the homogeneity of the film quality is significantly damaged. In addition, since the control values can be set more strictly than in the comparative example, unevenness in homogeneity within a lot or between lots can be suppressed, whereby stable film formation with a homogeneous film quality can be continued.

<Second Embodiment>

Next, the second embodiment of the present invention will be described. 9 is a schematic cross-sectional view of a sputtering device 200 according to another embodiment of the present invention. In Fig. 9, the X-axis, Y-axis, and Z-axis represent three axial directions orthogonal to each other, and the Z-axis corresponds to the vertical direction (height direction).

The sputtering device 200 includes a vacuum chamber 201 , a substrate holder 202 , a plurality of rotary cathodes RC, and a blocking plate 206 . A plurality of rotary cathodes (RC) are arranged at equal intervals along the Y-axis direction. Each rotary cathode (RC) includes a cylindrical target 203, a cylindrical backing tube 204 supporting the inner circumferential surface of the target 203, and a magnet unit 205 disposed inside the target 203. have

The vacuum chamber 201 is connected to the vacuum pump 207, and is configured to be capable of evacuating or maintaining a predetermined reduced pressure atmosphere therein. The substrate holder 202 is disposed inside the vacuum chamber 201 and supports the substrate W in a vertical position. The vacuum chamber 201 and substrate holder 202 are typically connected to ground potential. The substrate W is, for example, a rectangular glass substrate with a width of 1850 mm or more and a length of 1500 mm or more.

Each target 203 is configured to be rotatable around an axis parallel to the Z-axis direction (in the circumferential direction of the target 203). The target 203 is made of a film forming material for forming a film on the substrate W. Typical examples of the film-forming material include metals, alloys, metal oxides, metal nitrides, and synthetic resins. In this embodiment, a metal or alloy target having conductivity is used.

Each backing tube 204 is a metal plate supporting the rear surface of the target 203 and is connected to a power supply having an RF power source or DC power source installed outside the vacuum chamber 201 and not shown in the figure.

A plurality of magnet units 205 are arranged inside each target 203 along the axial direction of each target 203 . A magnetic circuit for forming a magnetic field on the surface (sputtering surface) of the target 203 facing the substrate W is constituted. As described with reference to FIG. 2, each magnet unit 205 is a yoke ( 53).

The anti-chacking plate 206 is disposed around the rotary cathode RC, and the sputtering material (film forming material) flying from the target 3 is applied to the inner surface of the side wall of the vacuum chamber 201 or the outer peripheral area of the substrate W (substrate W). A plasma space P for generating plasma is partitioned between the target 203 and the substrate holder 202 while preventing attachment to the periphery of the holder 2 . The vacuum chamber 201 is equipped with a gas introduction line 209 for introducing a sputtering gas such as Ar (argon) from the gas source 209s into the plasma space P.

When forming a film on the substrate W by the sputtering device 200, a sputtering gas is introduced from the gas introduction line 209 into the plasma space P, and each target 3 is rotated around the axis at a constant speed. At the same time as rotating, by applying RF power or DC power from the power supply source to the target 203 through the backing tube 204, a magnetron discharge is generated in the plasma space P.

In the sputtering apparatus 200, when the target 203 rotates around its axis, erosion proceeds evenly in the circumferential direction of the target 203. For this reason, the use efficiency of the target 203 can be improved.

In this embodiment, each rotary cathode RC moves each magnet unit 205 in the radial direction of the target 203, as shown in FIG. 10, and moves each magnet unit 205 to the target 203. It has a driving part 211 capable of swinging in the circumferential direction. Since each magnet unit 205 is configured to be movable in the radial direction of the target 203, the sputtering rate of the target 203 can be controlled. In addition, since each magnet unit 205 is configured to be able to swing in the circumferential direction of the target 203, the shape of the film to be formed can be manipulated to some extent. The drive unit 211 is configured to be able to adjust the swing width and swing speed of the magnet unit 205 .

[Explaining that film distribution can be adjusted by adjusting the radial direction of the magnet unit]

In general, it is preferable that the erosion rate of the plurality of rotating tube-shaped cathodes (rotary cathodes) is the same, but the distance to the factor (anode or other rotary cathode) affecting the behavior of electrons or the very small difference in quality of the target In some cases, the same erosion rate cannot be obtained due to factors such as In addition, in order to obtain a desired film quality distribution, there is a case where the erosion rate is forcibly set to be different.

The erosion speed is accelerated because the diameter of both targets is reduced along with erosion and the distance to the magnet unit is getting closer. , causing a change in membranous distribution.

Therefore, in order to maintain the target erosion rate balance, it is necessary to adjust the radial position of the magnet unit along with the progress of erosion.

In addition, when some or all of the magnets used in the magnet unit are electromagnets, the same effect can be obtained by adjusting the inlet current*.

That is, it is possible to adjust the erosion rate of the target surface according to the magnitude or direction of the current flowing in the coil of the electromagnet.

[Explaining that the film distribution can be adjusted by adjusting the fluctuation in the circumferential direction of the magnet unit]

The film thickness distribution on a substrate filmed by one tubular target is influenced by the position of the magnet unit in the circumferential direction. In general, when the magnet unit is disposed at a position facing the substrate, a left-right symmetric steering (bell) distribution is obtained, and when the magnet unit is disposed at a position rotated from the position facing the substrate, the peak position becomes a left-right asymmetrical steering (belt bell) distribution that moves in the direction of rotation. This is due to the fact that the position from which the target particles are emitted changes correspondingly to the position of the magnet unit (see FIGS. 11(A) and (B)).

A technique for manipulating the obtained film thickness distribution by utilizing this property and swinging the magnet unit in the circumferential direction during film formation is known (Fig. 12(A)).

As the erosion of the target progresses, the diameter of the target decreases, and the film thickness distribution changes accordingly. In general, the film thickness distribution is changed to a smoother steering (beam) type due to the effect that the particle emission position moves away from the substrate (FIG. 12(B)). As a countermeasure against such a change, it is effective to adjust the rocking pattern of the magnet unit in the circumferential direction (Fig. 12(C)).

As erosion progresses, it is possible to keep the film thickness distribution by reducing the swinging width of the magnet unit or by adjusting the swinging speed so that the magnet unit stays at a position facing the substrate for a long time.

In addition, when some or all of the magnets used in the magnet unit are electromagnets, the same effect can be obtained by adjusting the inflow current pattern corresponding to the rocking position.

The position of the magnet unit in the radial direction, the swing pattern in the circumferential direction, and the inflow current or the inflow current fluctuation pattern are the position in the X-axis direction and the movement pattern in the Y-axis direction of each magnet unit 5 shown in the first embodiment. It is a concept corresponding to the inflow current or the inflow current variation pattern. Therefore, if the description of the first embodiment is interpreted interchangeably with the above, it can be seen that the first embodiment is also applicable to the rotary cathode. Similarly, this embodiment can also be applied to the Planar cathode (first embodiment).

[control part]

The sputtering device 200 of this embodiment further includes a control device 220 that controls the position of each magnet unit 5 and the like. 13 is a block diagram showing the configuration of parts according to the present invention among the functions of the control device 220. The control device 220 has an input unit 21, an optimal solution calculation unit 22, and an output unit 23, similarly to the first embodiment.

In this embodiment, the configuration of the optimal solution calculation unit 22 is different from that of the first embodiment described above. The optimal solution calculation unit 22 in this embodiment is constituted by a prediction unit 221, a state estimation unit 224, and an optimization unit 223. In addition, the function of the prediction unit 221 is also different from that of the first embodiment.

The prediction unit 221 of the present embodiment is a function that takes film formation conditions and device state as hidden parameters as arguments, and takes as a return value a film quality prediction value when it is assumed that film formation has been performed under the film formation conditions and device state. . The method of calculating the predictive value of the film quality is performed based on a mathematical model in which physical phenomena related to sputtering are reproduced by a program.

The device state, which is a hidden parameter, is a physical quantity that is known to have an effect on film formation, such as the target erosion progress state, but whose value is unknown due to the absence of a measuring device, or a completely unknown but film It is a vector representation of the modeling of the factors influencing the formation with white noise.

By inputting film formation conditions and an appropriate device state to the prediction unit 221, film quality distribution can be predicted for any film formation condition. In general, since the device state, which is the hidden parameter, is unknown, estimation of the device state is indispensable in order to use the prediction unit 221.

Therefore, the state estimating unit 224 is responsible for estimating the device state using the actual film formation result.

The state estimation unit 224 calculates an estimated value of the device state using the maximum estimation method or the MAP estimation method based on the actual film formation conditions and the film formation result. For the calculation, various mathematical optimization algorithms such as gradient descent, Markov chain Monte Carlo method, or the like can be used.

In the first embodiment, the error between the predicted value and the measured value of the film quality was mechanically compensated, whereas in the second embodiment, the problem of why the error occurred could be theoretically explained by estimating the state of the device. there is. Therefore, there is an advantage in that the reliability of the prediction is high and that the homogeneity of the film quality can be continuously maintained by predicting the transition of the device state during the period even if the actual film formation result has not been obtained for a long period of time.

Both the correction unit 221 of the first embodiment and the state estimation unit 224 of the second embodiment are introduced for the purpose of improving prediction accuracy. Therefore, the state estimating unit 224 can be regarded as one form of the correcting unit 221 .

Fig. 14 is a flowchart showing one example of the processing procedure executed by the control device 220 of the present embodiment.

The input unit 21 acquires input information including film formation conditions and measurement values of the sputtering device 200 (step 201). Subsequently, the optimum solution calculation unit 22 (prediction unit 221) calculates a film quality homogeneity prediction value of the film forming material on the substrate W based on the input information obtained by the input unit 21, and based on the calculated prediction value , it is determined whether or not the homogeneity of the film quality is within the target range (steps 202 and 203).

Subsequently, the optimal solution calculating unit 22 (state estimating unit 224) calculates the likelihood of the current device state based on the input information obtained by the input unit 21 when the homogeneity of the film quality is not within the target range. The film formation condition that makes the maximum is calculated (estimated) (step 204).

Subsequently, the optimum solution calculation unit 22 (optimization unit 223) can satisfy the target film quality homogeneity for setting conditions such as the position of each magnet unit 205 at which the possibility of the device state is maximized. An optimal solution that exists is searched for (step 205).

Subsequently, the output unit 23 individually calculates the amount of adjustment to the optimal solution of each current magnet unit 205 based on the optimal solution calculated by the optimal solution calculation unit 22, and outputs it to a display unit not shown (step 206). Alternatively, the output unit 23 generates a control command based on the calculated optimal solution of each magnet unit 205, and sets the setting condition of each magnet unit 205 to the optimal solution through an adjustment unit not shown. .

As mentioned above, although embodiment of this invention was described, this invention is not limited only to the above-mentioned embodiment, It goes without saying that various changes can be added.

For example, in the above embodiment, the adjustment unit 10 automatically adjusts the position of the magnet units 5 and 205 based on a control command from the control devices 20 and 220, but this is limited to Instead, the position of the magnet units 5 and 205 can be adjusted by the operator. In this case, since the control unit 20, 220 can perform the position adjustment operation for the designated magnet unit 5, 205 based on the adjustment amount calculated by the control unit 20, 220, the operator's The position of the magnet unit 5, 205 can be quickly adjusted regardless of skill level.

Moreover, in the above embodiment, although the control apparatuses 20 and 220 were comprised as a part of sputtering apparatus 100, it is not limited to this and may be comprised independently of sputtering apparatuses 100 and 200. For example, the control devices 20 and 220 may be configured as a part of a management device connected to a plurality of sputtering devices through a network. In this case, evaluation of homogeneity of film quality in a plurality of sputtering devices, calculation of an optimal solution such as the position of a magnet unit, generation of a control command for adjusting the position of a magnet unit, etc. can be performed with one control device 20, 220. .

In addition, in the above first embodiment, an example in which a plurality of magnet units 5 are arranged with respect to a single target 3 has been described, but a multi-cathode type magnetron sputtering device in which a plurality of targets 3 are arranged in the same plane. Also, the present invention is applicable. In this case as well, as schematically shown in FIGS. 15(A) and (B), the desired homogeneity of the film quality is obtained corresponding to the progress of the erosion of each target 3. Arranged on the back surface of each target 3 Since each of the magnet units 5 thus formed can move in the X-axis direction and swing in the Y-axis direction, the same effect as in the first embodiment can be obtained.

Further, in each of the above embodiments, an example of application to a magnetron sputtering apparatus in which a plurality of magnet units are respectively disposed on a plurality of targets has been described, but the present invention can also be applied to a magnetron sputtering apparatus in which a single magnet unit is disposed in a single target. do.

1, 201: vacuum chamber
3, 203: target
5, 205: magnet unit
10: adjustment unit
20, 220: control device
21: input unit
22: Optimal solution calculation unit
23: output unit
100, 200: sputtering device
221: prediction unit
222: correction unit
223: optimization unit
224: state estimation unit
W: substrate

Claims (10)

one or more targets disposed facing the substrate and made of a film-forming material;
one or more magnet units disposed on the rear surface of the target;
setting conditions including at least one of a position of each of the magnet units, a movement pattern of each of the magnet units, and an inflow current or an inflow current variation pattern of an electromagnet constituting each of the magnet units; a control device having an optimum solution calculation unit that calculates an optimum solution of the set condition for at least one of the magnet units based on input information including at least a film quality measurement value of a film forming material on the substrate;
A sputtering device comprising an adjustment unit capable of individually adjusting the setting conditions of the magnet unit based on the optimal solution. According to claim 1,
The optimal solution calculation unit calculates the membrane quality homogeneity prediction value for the set condition of each of the magnet units, and based on the predicted value, the set condition of each magnet unit that can satisfy a predetermined membrane quality homogeneity set in advance A sputtering device that derives. According to claim 2,
The sputtering device of claim 1 , wherein the optimal solution calculation unit further has a correcting unit correcting the predicted value based on the input information. According to claim 3,
The sputtering device according to claim 1 , wherein the correcting unit performs correction by estimating the state of the sputtering device based on the input information. According to any one of claims 1 to 4,
The film quality measurement value of the film-forming material on the substrate includes measurement data about the film quality of the film-forming material at a plurality of preset measurement points on the substrate. According to claim 5,
The film quality includes at least one of film thickness, sheet resistance, light transmittance, film stress, refractive index, etching property, and film density. According to any one of claims 1 to 6,
The sputtering device according to claim 1, wherein the optimal solution calculating unit calculates the optimal solution using a machine learning machine that has previously learned the relationship between film formation conditions and film quality. According to any one of claims 1 to 7,
The input information further includes at least one of a type of film forming material, a surface shape of the target, a voltage applied to the target, a discharge time, a type of sputtering gas, and a pressure during film formation. A control method for a sputtering apparatus having one or more targets disposed facing a substrate and made of a film-forming material, and one or more magnet units disposed on a back surface of the target, comprising:
setting conditions including at least one of a position of each of the magnet units, a movement pattern of each of the magnet units, and an inflow current or an inflow current variation pattern of an electromagnet constituting each of the magnet units; Calculating an optimal solution of the set condition for at least one of the magnet units based on input information including at least a film quality measurement value of a film forming material on the substrate;
A control method of a sputtering device for individually adjusting the setting conditions of the magnet unit based on the optimal solution. A control device for controlling a sputtering device having at least one target disposed opposite to a substrate and made of a film-forming material, and at least one magnet unit disposed on a rear surface of the target, comprising:
setting conditions including at least one of a position of each of the magnet units, a movement pattern of each of the magnet units, and an inflow current or an inflow current variation pattern of an electromagnet constituting each of the magnet units; and an optimum solution calculation unit that calculates an optimum solution of the set condition for at least one of the magnet units based on input information including at least a film quality measurement value of a film forming material on the substrate.

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