JP7495387B2 - Sputtering Equipment - Google Patents

Description

The present invention relates to a sputtering device.

In the manufacture of organic EL displays and the like, a technique is known in which a film is formed on a substrate using a sputtering device. Among such sputtering devices, there are known sputtering devices that tilt the main scattering direction of sputtered particles relative to the substrate or that provide a shielding member between the target and the substrate in order to achieve a uniform film thickness and reduce damage to the substrate's underlayer (for example, Patent Document 1).

JP 2019-090083 A

On substrates with unevenness on the deposition surface, the amount of sputtered particles deposited on the sides of the unevenness tends to be small, leaving room for improvement in terms of uniformity of film thickness.

The present invention provides a technology that aims to make film thickness uniform.

According to the present invention,
A target that sputters particles toward a substrate;
a magnet that is disposed so that a main scattering direction of sputtered particles from the target is an oblique incidence direction inclined at an angle θ from a normal direction of the substrate to a predetermined direction perpendicular to the normal direction, and that forms a magnetic field on a surface of the target;
a moving means including a guide rail extending in the predetermined direction, a slider that is guided by the guide rail and can move in the predetermined direction, and a support table that is mounted on the slider and supports the target, and which moves the target and the magnet reciprocally in an outward and return direction relative to the substrate in the predetermined direction;
a switching means for switching the orientation of the magnet with respect to the normal direction such that the main scattering direction is changed from a first oblique incidence direction during the outbound path to a second oblique incidence direction during the return path, which is a direction opposite to the first oblique incidence direction and the normal direction, in response to a change in the direction of movement of the target and the magnet by the moving means from an outbound path, which is the direction of movement on the outbound path, to a return path, which is the direction of movement on the return path .
A sputtering apparatus is provided.

The present invention provides a technology that can achieve uniform film thickness.

1A and 1B are schematic diagrams of a sputtering apparatus according to one embodiment of the present invention. 4A and 4B are explanatory views of a film forming operation. 5A and 5B are schematic diagrams of a sputtering apparatus according to another embodiment of the present invention. 4A and 4B are explanatory views of a film forming operation. 13A and 13B are explanatory views of a film forming operation of a sputtering apparatus according to still another embodiment. 1A to 1C are diagrams showing an example of a flat target, and FIG. 1D is a diagram showing another example of relative movement between the substrate and the target.

The following embodiments are described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe multiple features, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicate explanations are omitted.

First Embodiment
<Configuration of the sputtering device>
1(A) and 1(B) are schematic diagrams of a sputtering apparatus 1 according to an embodiment of the present invention, where Fig. 1(A) is a side view of the sputtering apparatus 1 and Fig. 1(B) is a top view of the sputtering apparatus 1. In each drawing, arrow Z indicates the up-down direction (gravity direction), and arrows X and Y indicate horizontal directions that are orthogonal to each other.

The sputtering apparatus 1 is a film forming apparatus that forms a film on the substrate 100, and is applicable to manufacturing apparatuses for manufacturing electronic devices such as display devices (such as flat panel displays), thin-film solar cells, and organic photoelectric conversion elements (organic thin-film imaging elements), as well as optical components, and is particularly applicable to manufacturing apparatuses for manufacturing organic EL panels. When applied to the manufacture of organic EL panels, for example, an organic film is formed in advance on the underside of the substrate 100, and the sputtering apparatus 1 forms an electrode film on the organic film by sputtering.

The sputtering apparatus 1 has a box-shaped vacuum chamber 2. The vacuum chamber 2 is connected to a vacuum pump (not shown), and the internal space can be depressurized by exhausting the vacuum pump. An inert gas such as argon is supplied to the internal space of the vacuum chamber 2 by a gas supply unit 3.

The sputtering apparatus 1 includes a moving unit 4 that transports a substrate within a vacuum chamber 2. The moving unit 4 includes a pair of guide rails 4a and a carrier 5 that moves while being supported by the pair of guide rails 4a. Each guide rail 4a extends in the X direction, and the pair of guide rails 4a are spaced apart in the Y direction. The moving unit 4 has a driving mechanism such as a linear motor or a ball screw mechanism, and uses its driving force to reciprocate the carrier 5 in the X direction along the pair of guide rails 4a as shown by the solid and dashed lines in FIG. 1(B). The path of movement from the solid line position to the dashed line position is called the outbound path, and the opposite path of movement from the dashed line position to the solid line position is called the return path.

The carrier 5 has a holding portion 5a that holds the substrate 100. The substrate 100 is transported from the gate 2a into the vacuum chamber 2 and held by the carrier 5. As the carrier 5 moves, the substrate 100 moves back and forth in the X direction in the vacuum chamber 2 in a horizontal position, with its width direction being the Y direction. During the reciprocating process, sputtered particles scattered from the target 6 are deposited on the underside of the substrate 100, forming a film. The substrate 100 with the film formed is transported out of the vacuum chamber 2 from the gate 2a.

In this embodiment, the target 6 is a rotating target that can rotate freely around a rotation center line C1 in the Y direction. The target 6 is supported by a pair of support bases 10. One of the support bases 10 is provided with a motor 11, and the target 6 rotates by the driving force of the motor 11, which serves as a driving source.

The target 6 has a cylindrical shape, and a cathode electrode 7 is provided on its inner peripheral surface. A voltage is applied by a voltage application unit 8 to maintain the cathode potential and discharge. The sputtering device 1 of this embodiment is a magnetron sputtering device, and a magnet 9 that forms a magnetic field on the surface of the target 6 is disposed above the internal space of the target 6.

The magnet 9 comprises a central magnet 9a extending in the Y direction, a peripheral magnet 9b surrounding the central magnet 9a, and a yoke 9c. The peripheral magnet 9b is an annular magnet having a pair of straight portions extending in the Y direction parallel to the central magnet 9a and connection portions connecting both ends of the pair of straight portions in the Y direction. In Fig. 1(A) and elsewhere, a cross section of the pair of straight portions of the peripheral magnet 9b is illustrated, and in Fig. 1(B) the planar shape of the magnet 9 is illustrated.

The central magnet 9a and the peripheral magnets 9b have opposite polarities, and the magnetization direction of the central magnet 9a is in the direction of the central reference line N0. The central reference line NO is a straight line that passes through the center of the width of the magnetic pole of the central magnet 9a (the center of the X direction in the posture of FIG. 1(A)) and extends in a direction perpendicular to the surface of the target 6 (the radial direction of the target 6). In the posture of FIG. 1(A), the central reference line NO extends in the Z direction, is a line that passes through the rotation center line C1 of the target 6, and is perpendicular to the transport surface of the substrate 100. The magnetization direction of the peripheral magnet 32 extends parallel to the central magnet 9a, and the inner ends of the central magnet 9a and the peripheral magnet 9b are connected by a yoke 9c. As a result, the magnetic field near the surface of the target 6 has magnetic field lines that loop back from the magnetic pole of the central magnet 9a to the straight part of the peripheral magnet 9b. This magnetic field captures electrons, concentrates plasma near the surface of the target 6, and increases the efficiency of sputtering.

The sputtering device 1 is equipped with a switching unit 12. The switching unit 12 includes a motor 13, which is a drive source, and a rotating shaft 14. The motor 13 is built into the other support table 10, and rotates the rotating shaft 14 via a transmission mechanism (e.g., a gear mechanism) not shown. The rotating shaft 14 extends in the Y direction coaxially with the rotation center line C1 of the target 6, and is rotatably supported by the pair of support tables 10. The magnet 9 is connected to the rotating shaft 14, and rotates with the rotation of the rotating shaft 14, switching its orientation on the Z-X plane.

The sputtering apparatus 1 is equipped with a control unit 15. The control unit 15 includes at least one processor, at least one storage device, and an interface for inputting and outputting data from and to sensors and actuators, and controls the sputtering apparatus 1. The storage device is, for example, a memory such as a RAM or a ROM. The processor executes a program stored in the storage device, and performs drive control of the motors 11, 13 and the moving unit 4, etc.

<Film formation operation>
The film formation operation of the sputtering device 1 will be described with reference to Figures 2(A) and 2(B). While the substrate 100 is continuously moved by the moving unit 4, sputter particles P are scattered from the target 6 onto the substrate 100 and deposited on the lower surface of the substrate 100 to form a film. Figure 2(A) shows the film formation operation when the substrate 100 moves forward, and the substrate 100 is moved in the X direction (M1 direction). Figure 2(B) shows the film formation operation when the substrate 100 moves backward, and the substrate 100 is moved in the opposite direction (M2 direction) in the X direction. During film formation, the motor 11 is driven, and the target 6 rotates (spins) continuously, for example, in the direction of the arrow R1 (clockwise).

The elliptical loop L near the surface of the target 6 shown in Figures 2(A) and 2(B) shows a schematic representation of the area where plasma is concentrated. It is known that sputter particles are concentrated and scattered from the point where the magnetic flux density component in the normal direction of the surface of the target 6 is zero. This point is located between the straight parts of the central magnet 31 and the peripheral magnet 32. As shown in Figure 1(A), when the central reference line N0 is oriented in the normal direction Z1 (Z direction in this embodiment) of the substrate 100, and the sputter particles emitted from the target 6 are deposited on the transport surface, the distribution of the deposition rate, which is the amount of deposition per unit time, is a mountain-shaped distribution in which the rate peaks near the central reference line N0 and decreases on one side and the other side of the X direction. Therefore, the direction of the central reference line N0 can be called the main scattering direction of the sputter particles.

When the underside of the substrate 100, which is the deposition surface, has irregularities as shown in Figures 2(A) and 2(B), if the main scattering direction is oriented in the normal direction of the substrate 100 as in Figure 1(A), the film thickness on the underside of the irregularities tends to be thicker and the film thickness on the side of the irregularities tends to be thinner. In this embodiment, the orientation of the magnet 9 causes the main scattering direction to be an oblique incidence direction inclined with respect to the normal direction Z1 of the substrate 100, thereby promoting the deposition of sputtered particles P on the side of the irregularities and achieving a uniform film thickness.

As shown in FIG. 2(A), while the substrate 100 moves in the M1 direction, the switching unit 12 sets the orientation of the magnet 9 so that the main scattering direction is the oblique incidence direction D1, which is inclined by +θ in the X direction with respect to the normal direction Z1. This promotes film formation on the side of the uneven surface of the substrate 100 that is on the front side in the M1 direction (corresponding to the right side in the figure).

When the substrate 100 reaches a switching point from the forward path to the return path, the moving direction of the substrate 100 is switched from the M1 direction to the opposite M2 direction, as shown in Fig. 2B. The switching unit 12 switches the orientation of the magnet 9 so that the main scattering direction becomes the oblique incidence direction D2 inclined by -θ in the X direction with respect to the normal direction Z1. In Fig. 2A and Fig. 2B, the oblique incidence directions D1 and D2 are in an opposite relationship with respect to the Z1 direction. While the substrate 100 moves in the M2 direction, the main scattering direction is inclined by -θ in the X direction with respect to the normal direction Z1, and thus film formation is promoted on the side surface of the unevenness of the substrate 100 that is on the front side in the M2 direction (corresponding to the left side in the figure). By the reciprocation of the substrate 100, a more uniform film thickness can be formed for the unevenness of the substrate 100 In this manner, in this embodiment, the main scattering direction of the sputtered particles P with respect to the substrate 100 is set to the oblique incidence directions D1 and D2, and the oblique incidence directions D1 and D2 are changed according to the change in the moving direction of the substrate 100, so that a more uniform film thickness can be formed for the unevenness. Note that, in this embodiment, the angle θ is the same for the inclination angle +θ in the forward path and the inclination angle −θ in the return path, but they may be different, in other words, the oblique incidence directions D1 and D2 do not have to be symmetrical with respect to the normal direction Z1.

Second Embodiment
3(A) and 3(B) are schematic diagrams of a sputtering apparatus 1 according to another embodiment of the present invention, where Fig. 3(A) is a side view of the sputtering apparatus 1 and Fig. 3(B) is a top view of the sputtering apparatus 1. Regarding the sputtering apparatus 1 of the second embodiment, a configuration different from that of the sputtering apparatus 1 of the first embodiment will be described.

The sputtering apparatus 1 of this embodiment includes a shielding unit 16. The shielding unit 16 is an adhesion prevention unit that structurally restricts the scattering range of sputtered particles relative to the substrate 100 during film formation. The shielding unit 16 includes a fixed shielding member 17 arranged to surround the target 6, and a movable shielding member 18. The fixed shielding member 17 is a box-shaped member with an opening 17a formed on the top, and the movable shielding member 18 is a flat member that partially opens and closes the opening 17a.

The opening 17a and the movable shielding member 18 are located between the substrate 100 and the target 6, and the sputtered particles emitted from the target 6 pass through the opening 17a and reach the substrate 100. Therefore, the portion of the opening 17a that is not closed by the movable shielding member 18 is within the scattering allowable range, and the portion that is closed by the movable shielding member 18 is within the scattering restricted range.

The movable shielding member 18 is provided so as to be able to slide freely in the X direction, and moves due to the driving force of the motor 13', which is its driving source. The driving force of the motor 13' is transmitted to the movable shielding member 18 via a transmission mechanism (not shown). The transmission mechanism is, for example, a ball screw mechanism or a rack-pinion mechanism. The motor 13' also serves as the driving source of the switching unit 12. The driving force of the motor 13' is transmitted to the rotating shaft 14 via a transmission mechanism (not shown). The transmission mechanism is, for example, a gear mechanism.

In this embodiment, the switching unit 12 and the shielding unit 16 share the motor 13' as a drive source. By sharing the motor, costs can be reduced and the switching of the orientation of the magnet 9 can be linked with the movement of the movable shielding member 18. However, the switching unit 12 and the shielding unit 16 may be provided with separate drive sources and operated independently.

The movable shielding member 18 is maintained at an anode potential. The cathode potential of the cathode electrode 7 is, for example, about 200 V to 400 V. By maintaining the movable shielding member 18 at an anode potential (for example, earth potential; the same potential as the wall of the vacuum chamber 2), sputtered particles are more likely to adhere to the movable shielding member 18, improving the effect of the movable shielding member 18 in restricting the range of scattering onto the substrate 100.

The film formation operation of the sputtering device 1 of this embodiment will be described with reference to Figures 4(A) and 4(B).

As shown in FIG. 4A, while the substrate 100 moves in the M1 direction, the switching unit 12 sets the orientation of the magnet 9 so that the main scattering direction is the oblique incidence direction D1, as in the first embodiment. The movable shielding member 18 of the shielding unit 16 covers a part of the opening 17 to form a scattering tolerance range 17a'. The scattering tolerance range 17a' is a range that includes the part where the opening 17 intersects with the oblique incidence direction D1, and is a range in which the front range is narrower and the rear range is wider in the M1 direction with respect to the central reference line N0. This allows sputtered particles scattering in a direction close to the normal direction to the substrate 100 to adhere to the movable shielding member 18, preventing them from reaching the substrate 100. In addition, the deposition rate of sputtered particles on the side surfaces of the unevenness of the substrate 100 can be increased.

When the substrate 100 reaches the switching point from the forward path to the return path, the movement direction of the substrate 100 is switched from the M1 direction to the opposite M2 direction, as shown in FIG. 4(B). As in the first embodiment, the switching unit 12 switches the orientation of the magnet 9 so that the main scattering direction becomes the oblique incidence direction D2. The shielding unit 16 switches the allowable scattering range 17a' of sputtered particles by moving the movable shielding member 18. Since the switching unit 12 and the shielding unit 16 share the motor 13' as a driving source, by driving the motor 13', the switching of the orientation of the magnet 9 by the switching unit 12 and the switching of the allowable scattering range 17a' by the shielding unit 16 can be performed simultaneously in conjunction with each other.

The scattering tolerance range 17a' after switching is a range that includes the portion where the opening 17 intersects with the oblique incidence direction D2, and is a range in which the front range is narrower and the rear range is wider in the direction M2 relative to the central reference line N0. This allows sputtered particles scattering in a direction close to the normal direction to the substrate 100 to adhere to the movable shielding member 18, preventing them from reaching the substrate 100. The deposition rate of sputtered particles on the side surfaces of the unevenness of the substrate 100 can be increased. By the back and forth movement of the substrate 100, a more uniform film thickness can be formed for the unevenness of the substrate 100.

The movable shielding member 18 moves to a position symmetrical with respect to the normal direction Z1 before and after the movement. The position of the allowable scattering range 17a' is different before and after the movement of the movable shielding member 18, but the size is the same. However, the size of the allowable scattering range 17a' may be different before and after the movement of the movable shielding member 18, or the position may be asymmetric with respect to the normal direction Z1.

In this way, in this embodiment, the main scattering direction of the sputtered particles P relative to the substrate 100 is the oblique incident direction D1, D2, and the scattering range of the sputtered particles is regulated by the movable shielding member 18. In addition, different oblique incident directions D1, D2 are set according to changes in the moving direction of the substrate 100. Also, by switching the allowable scattering range 17a', a more uniform film thickness can be formed in spite of the unevenness.

Third Embodiment
In the second embodiment, the orientation of the magnet 9 is switched in response to a change in the moving direction of the substrate 100, and the main scattering direction of the sputtered particles P is switched, but the orientation of the magnet 9 may be fixed, and only the scattering allowable range 17a' may be switched by the shielding unit 16. Figures 5(A) and 5(B) are explanatory diagrams of the film formation operation in this embodiment.

In this embodiment, the switching unit 12 is not provided, and the central reference line N0 of the magnet 9 is oriented in the Z direction. The main scattering direction of the sputtered particles is the normal direction of the substrate 100, but by switching the scattering allowable range 17a', sputtered particles that are incident in the normal direction to the substrate 100 are blocked and sputtered particles that are incident obliquely are allowed to pass through.

As shown in FIG. 5A, while the substrate 100 moves in the M1 direction, the movable shielding member 18 of the shielding unit 16 covers a portion of the opening 17, forming a scattering allowable range 17a'. The movable shielding member 18 covers the range from directly above the target 6 to the front side in the M1 direction, including the central reference line N0, and the scattering allowable range 17a' is a range spaced from the central reference line N0 to the rear side in the M1 direction. Sputtered particles are scattered from the scattering allowable range 17a' in the oblique incidence direction D1 and deposited on the underside of the substrate 100. This promotes film formation on the side of the uneven surface of the substrate 100 that is on the front side in the M1 direction (corresponding to the right side in the figure).

When the substrate 100 reaches the switching point from the forward path to the return path, the movement direction of the substrate 100 is switched from the M1 direction to the opposite M2 direction, as shown in FIG. 5(B). The shielding unit 16 switches the allowable scattering range 17a' of the sputtered particles by moving the movable shielding member 18.

After switching, the movable shielding member 18 covers the range from directly above the target 6 to the front in the M2 direction, including the central reference line N0, and the scattering allowable range 17a' is a range spaced from the central reference line N0 to the rear in the M2 direction. Sputtered particles are scattered from the scattering allowable range 17a' in the oblique incidence direction D2 and deposited on the underside of the substrate 100. This promotes film formation on the side of the uneven surface of the substrate 100 that is on the front side in the M2 direction (corresponding to the left side in the figure).

The movable shielding member 18 moves to a position symmetrical with respect to the central reference line N0 before and after the movement. The position of the allowable scattering range 17a' is different before and after the movement of the movable shielding member 18, but the size is the same. However, the size of the allowable scattering range 17a' may be different before and after the movement of the movable shielding member 18, or the position may be asymmetric with respect to the normal direction Z1.

In this way, in this embodiment, the movable shielding member 18 restricts the scattering range of the sputtered particles, causing the sputtered particles P to scatter in the oblique incident directions D1 and D2 relative to the substrate 100. By the reciprocation of the substrate 100, a more uniform film thickness can be formed in relation to the unevenness of the substrate 100.

<Fourth embodiment>
In the first embodiment, the rotating target 6 is exemplified as the target 6, but a flat target may also be used. Fig. 6(A) shows one example. In the illustrated example, a flat target 19 is provided instead of the rotating target 6. The configuration of the magnet 9 is basically the same as that of the first embodiment. As exemplified in Fig. 6(B) and Fig. 6(C), the rotation of the rotation shaft 14 switches the orientation of the flat target 19 together with the magnet 6, thereby switching the main scattering direction.

In addition, in each of the above embodiments, a configuration in which sputter particles are emitted onto a substrate above the target is illustrated, but a configuration in which sputter particles are emitted onto a substrate below the target may also be used.

Fifth Embodiment
In each of the above-described embodiments, the moving unit 4 that moves the substrate 100 in the X direction has been exemplified as a unit that relatively moves the substrate 100 and the target 6 during film formation, but the target 6 may be moved instead. FIG. 6D shows one example of this.

The illustrated moving unit 21 includes a guide rail 22 extending in the X direction, and a slider 23 that is guided by the guide rail 22 and can move in the X direction. A pair of support stages 10 are mounted on the slider 23. The moving unit 21 has a driving mechanism such as a linear motor or a ball screw mechanism, and the driving force of the moving unit 21 causes the slider 23 to reciprocate in the X direction along the pair of guide rails 22 between the solid line position and the dashed line position. The substrate 100 is stopped in that position during film formation. While the slider 23 is moving, sputtering particles are released from the target 6 to form a film on the substrate 100.

The main scattering direction can be changed by switching the orientation of the magnet 9 when the target 6 moves in the forward direction M11 and the return direction M12.

Even in the configuration using the shielding unit 16 as in the second and third embodiments, by mounting the shielding unit 16 on the slider 23, the substrate 100 can be stopped during film formation, and the target 6 and the shielding unit 16 can be moved to perform the film formation operation. In this case as well, the position of the movable shielding member 18 can be changed between the movement in the forward direction M11 and the movement in the return direction M12 to switch the position of the scattering allowable range 17a'.

<Other embodiments>
The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

The invention is not limited to the above-described embodiment, and various modifications and variations are possible without departing from the spirit and scope of the invention. Therefore, the following claims are appended to disclose the scope of the invention.

1 Sputtering device, 6 Target, 9 Magnet, 16 Shielding unit, 100 Substrate

Claims (1)

A target that sputters particles toward a substrate;
a magnet that is disposed so that a main scattering direction of sputtered particles from the target is an oblique incidence direction inclined at an angle θ from a normal direction of the substrate to a predetermined direction perpendicular to the normal direction, and that forms a magnetic field on a surface of the target;
a moving means including a guide rail extending in the predetermined direction, a slider that is guided by the guide rail and can move in the predetermined direction, and a support table that is mounted on the slider and supports the target, and which moves the target and the magnet reciprocally in an outward and return direction relative to the substrate in the predetermined direction;
a switching means for switching the orientation of the magnet with respect to the normal direction such that the main scattering direction is changed from a first oblique incidence direction during the outbound path to a second oblique incidence direction during the return path, which is a direction opposite to the first oblique incidence direction and the normal direction, in response to a change in the direction of movement of the target and the magnet by the moving means from an outbound path, which is the direction of movement on the outbound path, to a return path, which is the direction of movement on the return path .
A sputtering apparatus comprising:

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