Sputtering apparatus

Abstract

This sputtering apparatus comprises: a substrate holding part that holds a substrate; a target which is disposed so as to face the substrate holding part and of which the relative positional relationship with the substrate holding part is movable in a first direction; and a plurality of radical irradiation devices in which radical irradiation positions on a film formation surface of the substrate are mutually different in the first direction. The plurality of radical irradiation devices can individually adjust the amount of radical generation.

Description

Sputtering Equipment

[0001] An embodiment of the present invention relates to a sputtering apparatus, and more particularly to a sputtering apparatus equipped with a radical irradiation device.

[0002] For small and medium-sized display devices such as smartphones, display devices using liquid crystal or OLED (organic light-emitting diode) have already been commercialized. Among these, OLED display devices using OLED, which is a self-emissive element, have the advantage of high contrast and no need for backlight compared to liquid crystal display devices. However, because OLED is composed of organic compounds, it is difficult to ensure high reliability of OLED display devices due to degradation of the organic compounds.

[0003] In recent years, development of so-called micro LED or mini LED displays, in which tiny LED chips are mounted within the pixels of a circuit board, has been progressing as next-generation display devices. LEDs are self-emitting elements similar to OLEDs. However, unlike OLEDs, LEDs are composed of stable inorganic compounds containing gallium (Ga) or indium (In). Therefore, compared to OLED display devices, micro LED display devices are more likely to ensure high reliability. Furthermore, LED chips have high luminous efficiency and can achieve high brightness. Therefore, micro LED display devices or mini LED display devices are expected to be next-generation display devices with high reliability, high brightness, and high contrast.

[0004] Gallium nitride films used in micro LEDs and the like are generally formed on sapphire substrates using metal organic chemical vapor deposition (MOCVD) or hydride vapor phase epitaxy (HVPE) at high temperatures of 800° C. to 1000° C. However, in recent years, a method for forming a gallium nitride film by sputtering has been developed, which allows film formation at relatively low temperatures (see, for example, Patent Document 1).

[0005] JP 2012-119569 A

[0006] If the gallium nitride layer that makes up the micro-LED could be deposited at low temperatures, it would be possible to form the micro-LED directly on a glass substrate. Micro-LEDs are formed by stacking multiple films with different compositions. Conventional sputtering equipment requires a separate target and chamber for each film with a different composition.

[0007] In view of the above problems, one object of one embodiment of the present invention is to provide a new sputtering apparatus.

[0008] A sputtering apparatus according to one embodiment of the present invention includes a substrate holder that holds a substrate, a target that is disposed opposite the substrate holder and whose positional relationship with the substrate holder is movable in a first direction, and a plurality of radical irradiation devices that irradiate radicals at different positions on a film formation surface of the substrate in the first direction. The plurality of radical irradiation devices are capable of individually adjusting the amount of radicals generated.

[0009] FIG. 1 is a top view showing an overview of a sputtering apparatus according to one embodiment of the present invention. FIG. 2 is a side view showing an overview of a sputtering apparatus according to one embodiment of the present invention. FIG. 3 is a top view showing an overview of a sputtering apparatus showing a modified example of one embodiment of the present invention. FIG. 4 is a diagram explaining a sputtering method according to one embodiment of the present invention. FIG. 5 is a diagram explaining a sputtering method according to one embodiment of the present invention. FIG. 6 is a diagram explaining a sputtering method according to one embodiment of the present invention. FIG. 7 is a diagram explaining a sputtering method according to one embodiment of the present invention. FIG. 8 is a diagram explaining a sputtering method according to one embodiment of the present invention. FIG. 9 is a diagram explaining a sputtering method according to one embodiment of the present invention.

[0010] Each embodiment of the present invention will be described below with reference to the drawings. The following disclosure is merely an example. Configurations that a person skilled in the art can easily arrive at by appropriately modifying the configuration of the embodiment while maintaining the gist of the invention are naturally included within the scope of the present invention. In order to clarify the explanation, the drawings may schematically depict the width, thickness, shape, etc. of each part compared to the actual embodiment. However, the illustrated shapes are merely examples and do not limit the interpretation of the present invention. In this specification and each drawing, elements similar to those described above with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0011] In each embodiment of the present invention, the direction from the first member to the second member is referred to as "up" or "upper." Conversely, the direction from the second member to the first member is referred to as "down" or "downward." For convenience of explanation, the terms "up" and "downward" are used in the description. However, for example, the vertical relationship between the first member and the second member may be reversed from that illustrated. In the following description, for example, the expression "second member above the first member" merely describes the vertical relationship between the first member and the second member as described above, and other members may be disposed between the first member and the second member. "Above" or "below" refers to the stacking order in a structure in which multiple layers are stacked. When referring to a second member above a first member, the first member and the second member may not overlap in a planar view. On the other hand, when referring to a second member vertically above a first member, the first member and the second member may overlap in a planar view.

[0012] In this specification, unless otherwise specified, expressions such as "α includes A, B, or C," "α includes any of A, B, and C," and "α includes one selected from the group consisting of A, B, and C" do not exclude cases where α includes multiple combinations of A to C. Furthermore, these expressions do not exclude cases where α includes other elements.

[0013] The following embodiments can be combined with each other as long as no technical contradiction occurs.

[0014] 1. First Embodiment A sputtering apparatus 10 according to one embodiment of the present invention and a sputtering method using the sputtering apparatus 10 will be described with reference to FIGS.

[0015] [1-1. Configuration of the Sputtering Apparatus] FIG. 1 is a top view showing an overview of a sputtering apparatus according to one embodiment of the present invention. As shown in FIG. 1, the sputtering apparatus 10 includes a chamber 100, a target unit 200, a substrate holder 300, a radical irradiation device 400, a control device 600, a position control device 610, and a movement mechanism 620. FIG. 1 shows only a portion of the chamber 100. The chamber 100 forms a closed space. Although not shown, the chamber 100 is provided with an exhaust port and a process gas supply port. The pressure inside the chamber 100 can be reduced via the exhaust port. Gases such as argon and nitrogen required for sputtering can be supplied into the chamber 100 via the process gas supply port.

[0016] A substrate 310, which is an object to be film-formed, is held by the substrate holding part 300. In the example of FIG. 1 , the substrate 310 is held by the substrate holding part 300 so that the main surface (film-forming surface) of the substrate 310 extends in the X-axis direction and the Z-axis direction. In other words, the substrate 310 is held by the substrate holding part 300 in a vertically placed state. The X-axis direction may be referred to as the "first direction." The Z-axis direction may be referred to as the "second direction." The Y-axis direction may be referred to as the "third direction."

[0017] The target unit 200 is disposed opposite the substrate holding unit 300. The target unit 200 includes a target 210 and a backing plate 220. As will be described in detail later, the target 210 is a flat target with its longitudinal axis in the Z-axis direction ( FIG. 3 ). The target 210 is composed of a material having the same composition as the thin film to be formed on the deposition surface of the substrate 310, or containing elements contained in the thin film. For example, if a gallium nitride (GaN) thin film is to be formed on the deposition surface, the target 210 is composed of GaN or gallium (Ga). The side of the target unit 200 facing the substrate holding unit 300 is referred to as the front side, and the side of the target unit 200 facing the radical irradiation device 400 is referred to as the back side. The target 210 is fixed to the front side of the backing plate 220, for example, by indium or the like.

[0018] A magnet or other member (not shown) is provided on the back surface of the backing plate 220. Electrons in the plasma are confined by the magnet, forming a high-density plasma region in front of the target 210. In this plasma region, a process gas is ionized. Argon, for example, is used as the process gas. The ionized argon is accelerated toward the target 210 in a sheath region formed between the plasma region and the target 210. The accelerated argon ions collide with the target 210, sputtering the target material.

[0019] In addition to the above-mentioned GaN and Ga, materials such as aluminum, aluminum nitride, indium, indium nitride, silicon, and silicon nitride can be used as the target 210. Materials obtained by doping the above-mentioned materials with impurities (dopants) may also be used as the target 210. For example, materials obtained by doping gallium nitride with magnesium or silicon as a dopant may also be used. Gallium nitride containing magnesium as a dopant functions as a P-type semiconductor. Gallium nitride containing silicon as a dopant functions as an N-type semiconductor.

[0020] A holding mechanism 630 that holds the target unit 200 is provided on the back side of the backing plate 220. The holding mechanism 630 is arranged on a moving mechanism 620. The moving mechanism 620 controls the positions of the holding mechanism 630 and the target unit 200 in the X-axis direction. A rail mechanism, for example, is used as the moving mechanism 620. However, other mechanisms may be used as the moving mechanism 620. A position control device 610 is provided on the moving mechanism 620. The position control device 610 detects the positions of the holding mechanism 630 and the target unit 200 in the X-axis direction that are controlled by the moving mechanism 620. A rotary encoder, for example, is used as the position control device 610.

[0021] The position control device 610 is connected to the control device 600. Based on a control signal from the control device 600, the position control device 610 controls the movement mechanism 620, thereby determining the positions of the holding mechanism 630 and the target unit 200 in the X-axis direction. Furthermore, the control device 600 acquires current position information of the holding mechanism 630 and the target unit 200 in the X-axis direction from the position control device 610. The control device 600 is connected to the radical irradiation device 400 (radical irradiation devices 410 to 440) described below. As will be described in detail later, the control device 600 controls the amount or type of radicals generated by the radical irradiation devices 410 to 440.

[0022] The target unit 200 is movable, and the relative positional relationship between the target unit 200 and the substrate holding unit 300 changes in the X-axis direction. In the example of FIG. 1 , the position of the substrate holding unit 300 is fixed in the X-axis direction, and the position of the target unit 200 moves. The movement of the target unit 200 in the X-axis direction may be a swing (reciprocating or repeating in the positive and negative directions on the X-axis) or a unidirectional passage. However, the position of the target unit 200 may be fixed in the X-axis direction, and the position of the substrate holding unit 300 may move, or both the target unit 200 and the substrate holding unit 300 may move as described above.

[0023] The radical irradiation device 400 is provided on the side wall of the chamber 100. In this embodiment, the radical irradiation device 400 includes a radical irradiation device 410 (A), a radical irradiation device 420 (B), a radical irradiation device 430 (C), and a radical irradiation device 440 (D). The radical irradiation devices 410 to 440 are all arranged so as to irradiate radicals onto the film formation surface of the substrate 310. The radical irradiation positions of the radical irradiation devices 410 to 440 differ in the X-axis direction. In this embodiment, the radical irradiation positions described above are realized by arranging the radical irradiation devices 410 to 440 side by side in the X-axis direction.

[0024] The radical irradiation device 410 includes a radical generator 411, a pipe 412, and a radical release port 413. The radical irradiation device 420 includes a radical generator 421, a pipe 422, and a radical release port 423. The radical irradiation device 430 includes a radical generator 431, a pipe 432, and a radical release port 433. The radical irradiation device 440 includes a radical generator 441, a pipe 442, and a radical release port 443. The radical generators 411 to 441 are provided outside the chamber 100. The pipes 412 to 442 are connected to the radical generators 411 to 441, respectively, and pass through the sidewall of the chamber 100. The radical release ports 413 to 443 are connected to the pipes 412 to 442, respectively, and are provided inside the chamber 100.

[0025] With process gas supplied to the radical irradiation devices 410 to 440, the plasma power supplies (e.g., microwave power supplies) provided in the radical generators 411 to 441 are controlled to be on, thereby generating plasma in the radical generators 411 to 441 and generating radicals resulting from the process gas. The amount of radicals generated can be adjusted by controlling the power supplied to the plasma power supplies.

[0026] The radicals generated in the radical generators 411 to 441 are guided into the chamber 100 through the pipes 412 to 442 and are emitted into the chamber 100 from the radical emission ports 413 to 443 .

[0027] The process gas supplied to the radical irradiation devices 410 to 440 is, for example, hydrogen (H ２ ) gas, ammonia (NH ３ ) gas, or nitrogen (N ２ ) gas. For example, hydrogen gas is supplied to the radical irradiation device 410, and hydrogen radicals are supplied into the chamber 100. Then, ammonia gas is supplied to the radical irradiation device 420, and ammonia radicals are supplied into the chamber 100. The ammonia radicals reach the thin film formed on the film formation surface of the substrate 310, thereby nitriding the thin film. The hydrogen radicals extract hydrogen from the ammonia radicals, thereby promoting the nitridation of the thin film. Gases other than those mentioned above may also be used as the gas supplied to the radical irradiation device 400.

[0028] The radical irradiation devices 410 to 440 can individually adjust the amount of radicals generated. The radical irradiation devices 410 to 440 may irradiate the substrate 310 with the same type of radicals, or at least some of the radical irradiation devices may irradiate the substrate 310 with a type of radical different from that of the other radical irradiation devices. In this case, a gas different from that supplied to the other radical irradiation devices is supplied to the radical irradiation device. The radical irradiation device 410 may be referred to as the "first radical irradiation device." The radical irradiation device 420 adjacent to the radical irradiation device 410 may be referred to as the "second radical irradiation device."

[0029] Fig. 2 is a side view showing an outline of a sputtering apparatus according to one embodiment of the present invention. Fig. 2 is a view of the sputtering apparatus 10 as viewed in the Y-axis direction. As shown in Fig. 2, the radical irradiation devices 410 to 440 are arranged in a matrix in the X-axis direction and the Z-axis direction. In the following description, the X-axis direction may be referred to as the row direction, and the Z-axis direction may be referred to as the column direction.

[0030] The radical irradiation device 410 includes radical irradiation devices Aa, Ab, Ac, and Ad. The radical irradiation devices Aa, Ab, Ac, and Ad are arranged side by side in the Z-axis direction, and the amount of radicals generated can be individually adjusted. The radical irradiation devices Aa, Ab, Ac, and Ad may irradiate the substrate 310 with the same type of radicals, or at least some of the radical irradiation devices may irradiate the substrate 310 with a type of radical different from that of the other radical irradiation devices.

[0031] The radical irradiation device 420 includes radical irradiation devices Ba, Bb, Bc, and Bd. The radical irradiation devices Ba, Bb, Bc, and Bd are arranged side by side in the Z-axis direction, and the amount of radicals generated can be individually adjusted. The radical irradiation devices Ba, Bb, Bc, and Bd may irradiate the substrate 310 with the same type of radicals, or at least some of the radical irradiation devices may irradiate the substrate 310 with a type of radical different from that of the other radical irradiation devices.

[0032] The radical irradiation device 430 includes radical irradiation devices Ca, Cb, Cc, and Cd. The radical irradiation devices Ca, Cb, Cc, and Cd are arranged side by side in the Z-axis direction, and the amount of radicals generated can be individually adjusted. The radical irradiation devices Ca, Cb, Cc, and Cd may irradiate the substrate 310 with the same type of radicals, or at least some of the radical irradiation devices may irradiate the substrate 310 with a type of radical different from that of the other radical irradiation devices.

[0033] The radical irradiation device 440 includes radical irradiation devices Da, Db, Dc, and Dd. The radical irradiation devices Da, Db, Dc, and Dd are arranged side by side in the Z-axis direction, and the amount of radicals generated can be individually adjusted. The radical irradiation devices Da, Db, Dc, and Dd may irradiate the substrate 310 with the same type of radicals, or at least some of the radical irradiation devices may irradiate the substrate 310 with a type of radical different from that of the other radical irradiation devices.

[0034] The radical irradiation device Aa may be referred to as a "first radical irradiation device," the radical irradiation device Ba may be referred to as a "second radical irradiation device," and the radical irradiation device Ab may be referred to as a "third radical irradiation device."

[0035] The radical irradiation devices Aa to Ad, the radical irradiation devices Ba to Bd, the radical irradiation devices Ca to Cd, and the radical irradiation devices Da to Dd may be referred to as "row units" of radical irradiation devices. In other words, a row unit is a unit formed by radical irradiation devices that are lined up in the Z-axis direction among multiple radical irradiation devices. In this case, it can be said that multiple row units of radical irradiation devices are arranged side by side in the X-axis direction.

[0036] In this embodiment, the row unit refers to one row of radical irradiation devices, but multiple rows of radical irradiation devices may be collectively defined as a row unit. For example, two rows of radical irradiation devices may be collectively defined as a row unit.

[0037] As will be described in detail later, when forming a film on the substrate 310, the radical irradiation devices can be controlled in units of rows. For example, the radical irradiation devices can be controlled so that the amount of radicals generated by the radical irradiation device of a selected specific row unit is greater than the amount of radicals generated by the radical irradiation devices of other row units. For example, the radical irradiation devices can be controlled so that the amount of radicals generated by the radical irradiation devices of other row units is 50% or less, 30% or less, 20% or less, or 10% or less of the amount of radicals generated by the radical irradiation device of the selected specific row unit. In the above control, the amount of radicals generated by the radical irradiation devices of other row units may be zero. When the amount of radicals generated is zero, it may be said that the radical irradiation devices of the other row units are in an off state. In this case, it may be said that the radical irradiation devices of the selected specific row units are in an on state. The radical irradiation devices of the selected specific row units may be sequentially switched in the X-axis direction.

[0038] As described above, in this embodiment, a configuration has been exemplified in which the radical irradiation device 400 emits radicals perpendicular to the film formation surface of the substrate 310 on the back side of the target unit 200, but the configuration is not limited to this. For example, the radical irradiation device 400 may be arranged on the back side of the target unit 200 so as to emit radicals from a direction inclined with respect to the film formation surface. Alternatively, the radical irradiation device 400 may be arranged so as to emit radicals parallel to the film formation surface.

[0039] In this embodiment, a configuration in which one target unit 200 is provided for the substrate 310 has been exemplified, but a plurality of target units 200 may be provided for the substrate 310 .

[0040] [1-2. Sputtering Method] The sputtering apparatus 10 shown in Fig. 1 and Fig. 2 is configured to be able to individually control each radical irradiation device as described above, and is therefore capable of depositing a high-quality thin film.

[0041] For example, in a plan view of the deposition surface of the substrate 310, the quality of the deposited thin film may be improved by controlling the radical irradiation device arranged in the area overlapping with the target 210 to the off state and the radical irradiation device arranged in the area not overlapping with the target 210 to the on state, or by controlling the amount of radicals generated by the radical irradiation device arranged in the area overlapping with the target 210 to be less than the amount of radicals generated by the radical irradiation device arranged in the area not overlapping with the target 210.

[0042] Specifically, when a GaN layer is formed by sputtering using a GaN target, the GaN layer tends to be deficient in nitrogen. Even in such a case, nitrogen can be replenished in the GaN layer by irradiating the GaN layer with nitrogen-containing radicals (e.g., the above-mentioned ammonia radical irradiation and hydrogen radical irradiation) after the GaN layer is formed. In other words, the film quality of the GaN layer can be improved by the radical irradiation.

[0043] Alternatively, in the above plan view, the film quality of the formed thin film may be improved by controlling the radical irradiation device arranged in the area overlapping with the target 210 to the on state and the radical irradiation device arranged in the area not overlapping with the target 210 to the off state, or by controlling the amount of radicals generated by the radical irradiation device arranged in the area overlapping with the target 210 to be greater than the amount of radicals generated by the radical irradiation device arranged in the area not overlapping with the target 210.

[0044] Specifically, when a GaN layer is formed by sputtering using a Ga target, the GaN layer can be formed by reactive sputtering in which Ga atoms (or Ga clusters) sputtered from the Ga target are deposited on the substrate 310 while being irradiated with nitrogen-containing radicals.

[0045] Alternatively, the on / off state of the radical irradiation device or the amount of radicals generated may be controlled according to the in-plane distribution of film thickness during film formation by the sputtering device 10. For example, if the film thickness in the peripheral portion of the substrate 310 is greater than that in the central portion, the amount of radicals generated by the radical irradiation device corresponding to the peripheral portion can be controlled to be greater than the amount of radicals generated by the radical irradiation device corresponding to the central portion. This control allows nitrogen to be replenished in the GaN layer in both the central and peripheral portions, thereby improving the film quality of the GaN layer.

[0046] [1-3. Modified Example of Sputtering Apparatus] Figure 3 is a top view showing an outline of a sputtering apparatus showing a modified example of one embodiment of the present invention. While Figure 1 illustrates a configuration using a flat target, Figure 3 will explain a configuration using a rotary target. The configurations of the substrate holding unit 300 and radical irradiation device 400 in Figure 3 are the same as those of the substrate holding unit 300 and radical irradiation device 400 in Figure 1, and therefore description thereof will be omitted.

[0047] As shown in Fig. 3, the sputtering apparatus 10 is provided with a target unit 500 in place of the target unit 200 in Fig. 1. The target unit 500 includes a support member 510, a fixing member 511, a yoke 512, a central magnet 513, a peripheral magnet 514, a backing tube 515, and a target 516. These members are shaped such that their elongated sides extend in the Z-axis direction.

[0048] The support member 510 is rotatably fixed to the chamber 100. The fixed member 511 is connected to the support member 510 and extends from the support member 510 toward the backing tube 515. A yoke 512 is fixed to the end of the fixed member 511. The central magnet 513 and the peripheral magnets 514 are fixed to the yoke 512 and extend from the yoke 512 toward the backing tube 515. The ends of the central magnet 513 and the peripheral magnets 514 on the backing tube 515 side have a curved shape that follows the inner wall of the backing tube 515.

[0049] The central magnet 513 and the peripheral magnets 514 have a linear shape extending in the Z-axis direction. The central magnet 513 and the peripheral magnets 514 rotate along the inner wall of the backing tube 515 around the support member 510. The support member 510 is fixed to a fixing member 511 and rotates together with the central magnet 513 and the peripheral magnets 514. However, the support member 510 may be fixed without rotating relative to the chamber 100. In this case, the fixing member 511 is connected to the support member 510 so as to be rotatable.

[0050] The target 516 is fixed to the backing tube 515. The backing tube 515 and the target 516 have a cylindrical shape centered on an axis extending in the Z-axis direction, and rotate around the support member 510. The target 516 rotates independently of the central magnet 513 and the peripheral magnets 514. When there is no particular distinction between the central magnet 513 and the peripheral magnets 514, they may be simply referred to as "magnets."

[0051] The central magnet 513 has a polarity opposite to that of the peripheral magnets 514. That is, these magnets form a magnetic field that steers from the central magnet 513 toward the peripheral magnets 514 (or vice versa). This magnetic field confines electrons in the plasma, forming a highly concentrated plasma region in the region corresponding to the central magnet 513 and the peripheral magnets 514. In the plasma region, a process gas is ionized. For example, argon is used as the process gas. The ionized argon is accelerated toward the target 516 in a sheath region formed between the plasma region and the target 516. The accelerated argon ions collide with the target 516, sputtering the target material.

[0052] As described above, according to the sputtering apparatus 10 of this embodiment, the amount of radicals generated and the type of radicals generated by the radical irradiation devices 400 arranged in the matrix direction are variable, so that appropriate radical irradiation conditions can be selected depending on the characteristics of the sputtering apparatus and the type of film to be formed.

[0053] 4A to 4D, a sputtering method using a sputtering apparatus 10 according to one embodiment of the present invention will be described. The configuration of the sputtering apparatus 10 used in this embodiment is the same as the configuration of the sputtering apparatus 10 shown in Fig. 1, so a description thereof will be omitted. In this embodiment, an embodiment in which a GaN layer is formed using a sputtering apparatus 10 in which GaN is used as the target 210 will be described.

[0054] 4A to 4D are diagrams illustrating a sputtering method according to one embodiment of the present invention. In these figures, the target unit 200 moves in the direction of the white arrow from the position shown in each figure. In these figures, the radical irradiation device in the row surrounded by a dotted line in a substantially rectangular shape with rounded corners and indicated by a filled arrow is the selected radical irradiation device. This radical irradiation device is either a radical irradiation device in the on state (radical irradiation devices in the region not surrounded by the dotted line are radical irradiation devices in the off state), or a radical irradiation device that generates more radicals than the other radical irradiation devices. In the following description, the position of the target unit 200 and the operation of each radical irradiation device 400 are realized by the control device 600, position control device 610, and movement mechanism 620 shown in FIGS. 1 and 3.

[0055] As shown in FIG. 4A, the target unit 200 is moving in a direction away from the radical irradiation devices Aa to Ad and in a direction toward the radical irradiation devices Ba to Bd. In this state, the radical irradiation devices Aa to Ad are selected. The selected radical irradiation devices Aa to Ad are in the on state, and the other radical irradiation devices (Ba to Bd, Ca to Cd, Da to Dd) are in the off state. Alternatively, the amount of radicals generated by the selected radical irradiation devices Aa to Ad is greater than the amount of radicals generated by the other radical irradiation devices (Ba to Bd, Ca to Cd, Da to Dd). In FIG. 4A, the target unit 200 does not overlap with the radical irradiation devices Aa to Ad in a plan view relative to the film formation surface of the substrate 310.

[0056] As shown in FIG. 4B, the target unit 200 is moving in a direction away from the radical irradiation devices Ba to Bd and in a direction toward the radical irradiation devices Ca to Cd. In this state, the radical irradiation devices Ba to Bd are selected. The selected radical irradiation devices Ba to Bd are in the on state, and the other radical irradiation devices (Aa to Ad, Ca to Cd, Da to Dd) are in the off state. Alternatively, the amount of radicals generated by the selected radical irradiation devices Ba to Bd is greater than the amount of radicals generated by the other radical irradiation devices (Aa to Ad, Ca to Cd, Da to Dd). In FIG. 4B, the target unit 200 does not overlap with the radical irradiation devices Ba to Bd in a plan view relative to the film formation surface of the substrate 310.

[0057] As shown in FIG. 4C , the target unit 200 is moving in a direction away from the radical irradiation devices Ca to Cd and in a direction toward the radical irradiation devices Da to Dd. In this state, the radical irradiation devices Ca to Cd are selected. The selected radical irradiation devices Ca to Cd are in the on state, and the other radical irradiation devices (Aa to Ad, Ba to Bd, Da to Dd) are in the off state. Alternatively, the amount of radicals generated by the selected radical irradiation devices Ca to Cd is greater than the amount of radicals generated by the other radical irradiation devices (Aa to Ad, Ba to Bd, Da to Dd). In FIG. 4C , the target unit 200 does not overlap with the radical irradiation devices Ca to Cd in a plan view relative to the film formation surface of the substrate 310.

[0058] As shown in FIG. 4D , the target unit 200 turns around at the right end of the substrate 310 and moves away from the radical irradiation devices Da to Dd and toward the radical irradiation devices Ca to Cd. In this state, the radical irradiation devices Da to Dd are selected. The selected radical irradiation devices Da to Dd are in the on state, while the other radical irradiation devices (Aa to Ad, Ba to Bd, Ca to Cd) are in the off state. Alternatively, the amount of radicals generated by the selected radical irradiation devices Da to Dd is greater than the amount of radicals generated by the other radical irradiation devices (Aa to Ad, Ba to Bd, Ca to Cd). In FIG. 4D , the target unit 200 does not overlap with the radical irradiation devices Da to Dd in a plan view of the film formation surface of the substrate 310.

[0059] As described above, in the sputtering method according to this embodiment, when viewed in the Y-axis direction, the target unit 200 moves in the X-axis direction in an area overlapping with the plurality of radical irradiation devices 400. When viewed in the Y-axis direction, the radical irradiation devices in the specific row units selected as described above are selected so as to follow the movement of the target unit 200. In other words, the radical irradiation devices in the specific row units selected as described above are sequentially switched in the X-axis direction depending on the positional relationship between the substrate 310 and the target unit 200 in the X-axis direction.

[0060] As described above, when a GaN layer is formed by sputtering using a GaN target, the GaN layer tends to be deficient in nitrogen. However, according to the sputtering method of this embodiment, radical irradiation is performed after the GaN layer is formed, thereby replenishing nitrogen in the GaN layer.

[0061] 5A to 5D, a sputtering method using a sputtering apparatus 10 according to one embodiment of the present invention will be described. The configuration of the sputtering apparatus 10 used in this embodiment is the same as the configuration of the sputtering apparatus 10 shown in FIG. 1, and therefore a description thereof will be omitted. In this embodiment, an embodiment in which a GaN layer is formed using a sputtering apparatus 10 in which Ga is used as the target 210 will be described.

[0062] 5A to 5D are diagrams illustrating a sputtering method according to one embodiment of the present invention. In these figures, the target unit 200 moves in the direction of the white arrow from the position shown in each figure. In these figures, the radical irradiation devices in the rows surrounded by a dotted line in a roughly rectangular shape with rounded corners and indicated by a solid arrow are radical irradiation devices in the on state (radical irradiation devices in the regions not surrounded by the dotted line are off), or radical irradiation devices that generate more radicals than the other radical irradiation devices. In the following description, the position of the target unit 200 and the operation of each radical irradiation device 400 are realized by the control device 600, position control device 610, and movement mechanism 620 shown in FIGS. 1 and 3.

[0063] As shown in FIG. 5A, the target unit 200 is moving from the area overlapping with the radical irradiation devices Aa to Ad in a direction approaching the radical irradiation devices Ba to Bd. In this state, the radical irradiation devices Aa to Ad are selected. The selected radical irradiation devices Aa to Ad are in the on state, and the other radical irradiation devices (Ba to Bd, Ca to Cd, Da to Dd) are in the off state. Alternatively, the amount of radicals generated by the selected radical irradiation devices Aa to Ad is greater than the amount of radicals generated by the other radical irradiation devices (Ba to Bd, Ca to Cd, Da to Dd). In FIG. 5A, the target unit 200 overlaps with the radical irradiation devices Aa to Ad in a plan view relative to the film formation surface of the substrate 310.

[0064] As shown in FIG. 5B, the target unit 200 is moving from the area overlapping with the radical irradiation devices Ba to Bd in a direction approaching the radical irradiation devices Ca to Cd. In this state, the radical irradiation devices Ba to Bd are selected. The selected radical irradiation devices Ba to Bd are in the on state, and the other radical irradiation devices (Aa to Ad, Ca to Cd, Da to Dd) are in the off state. Alternatively, the amount of radicals generated by the selected radical irradiation devices Ba to Bd is greater than the amount of radicals generated by the other radical irradiation devices (Aa to Ad, Ca to Cd, Da to Dd). In FIG. 5B, the target unit 200 overlaps with the radical irradiation devices Ba to Bd in a plan view relative to the film formation surface of the substrate 310.

[0065] As shown in FIG. 5C , the target unit 200 is moving from the area overlapping with the radical irradiation devices Ca to Cd in a direction approaching the radical irradiation devices Da to Dd. In this state, the radical irradiation devices Ca to Cd are selected. The selected radical irradiation devices Ca to Cd are in the on state, and the other radical irradiation devices (Aa to Ad, Ba to Bd, Da to Dd) are in the off state. Alternatively, the amount of radicals generated by the selected radical irradiation devices Ca to Cd is greater than the amount of radicals generated by the other radical irradiation devices (Aa to Ad, Ba to Bd, Da to Dd). In FIG. 5C , the target unit 200 overlaps with the radical irradiation devices Ca to Cd in a plan view relative to the film formation surface of the substrate 310.

[0066] As shown in FIG. 5D , the target unit 200 turns back at the right edge of the substrate 310 and moves from the area overlapping with the radical irradiation devices Da to Dd toward the radical irradiation devices Ca to Cd. In this state, the radical irradiation devices Da to Dd are selected. The selected radical irradiation devices Da to Dd are in the on state, and the other radical irradiation devices (Aa to Ad, Ba to Bd, Ca to Cd) are in the off state. Alternatively, the amount of radicals generated by the selected radical irradiation devices Da to Dd is greater than the amount of radicals generated by the other radical irradiation devices (Aa to Ad, Ba to Bd, Ca to Cd). In FIG. 5D , the target unit 200 overlaps with the radical irradiation devices Da to Dd in a plan view of the film formation surface of the substrate 310.

[0067] As described above, in the sputtering method according to this embodiment, when viewed in the Y-axis direction, the target unit 200 moves in the X-axis direction through an area that overlaps with a plurality of radical irradiation devices 400. When viewed in the Y-axis direction, the radical irradiation devices in the specific row units selected as described above are selected so as to overlap with the target unit 200. In other words, the radical irradiation devices in the specific row units selected as described above are sequentially switched in the X-axis direction depending on the positional relationship between the substrate 310 and the target unit 200 in the X-axis direction.

[0068] As described above, when a GaN layer is formed by sputtering using a Ga target, the GaN layer can be formed by reactive sputtering in which radical irradiation is performed simultaneously with the Ga film formation.

[0069] The above-described embodiments of the present invention may be combined as appropriate as long as they are not mutually inconsistent. Furthermore, even if a person skilled in the art appropriately adds or deletes components or modifies the design, or adds or omits steps or modifies conditions based on the embodiments, such combinations are included within the scope of the present invention as long as they include the gist of the present invention.

[0070] Even if there are other effects and advantages different from those brought about by the aspects of each of the above-mentioned embodiments, those that are clear from the description in this specification or that can be easily predicted by a person skilled in the art are naturally understood to be brought about by the present invention.

[0071] 10: Sputtering device, 100: Chamber, 200: Target section, 210: Target, 220: Backing plate, 300: Substrate holder, 310: Substrate, 400, 410, 420, 430, 440: Radical irradiation device, 411, 421, 431, 441: Radical generator, 412, 422, 432, 442: Piping, 413, 423, 433, 443: Radical outlet, 500: Target section, 510: Support member, 511: Fixing member, 512: Yoke, 513: Central magnet, 514: Peripheral magnet, 515: Backing tube, 516: Target

Claims

1. A sputtering apparatus comprising: a substrate holding section for holding a substrate; a target facing the substrate holding section and movable in a first direction relative to the substrate holding section; and a plurality of radical irradiation devices each having different radical irradiation positions on a film formation surface of the substrate in the first direction, wherein the amount of radicals generated by each of the plurality of radical irradiation devices can be individually adjusted.

2. A sputtering apparatus as described in claim 1, wherein the target has a longitudinal direction in a second direction perpendicular to the first direction, and the deposition surface extends in both the first direction and the second direction.

3. The sputtering apparatus of claim 2, wherein the plurality of radical irradiation devices include a first radical irradiation device and a second radical irradiation device arranged side by side in the first direction, and the first radical irradiation device and the second radical irradiation device are capable of individually adjusting the amount of radicals generated.

4. The sputtering apparatus of claim 3, wherein the plurality of radical irradiation devices include a third radical irradiation device arranged in the second direction relative to the first radical irradiation device, and the first radical irradiation device and the third radical irradiation device are capable of individually adjusting the amount of radicals generated.

5. The sputtering apparatus of claim 2, wherein the plurality of radical irradiation devices include a first radical irradiation device and a second radical irradiation device arranged side by side in the first direction, different gases are supplied to the first radical irradiation device and the second radical irradiation device, and the first radical irradiation device and the second radical irradiation device irradiate different types of radicals depending on the supplied gas.

6. A sputtering apparatus as described in claim 3 or 5, wherein the multiple radical irradiation devices include a third radical irradiation device arranged in the second direction relative to the first radical irradiation device, different gases are supplied to the first radical irradiation device and the third radical irradiation device, and the first radical irradiation device and the third radical irradiation device irradiate different types of radicals depending on the supplied gas.

7. A sputtering apparatus as described in claim 2, wherein the plurality of radical irradiation devices are arranged in a row in the first direction and the second direction, and the amount of radicals generated is adjustable for each row of the plurality of radical irradiation devices arranged in the second direction.

8. A sputtering apparatus as described in claim 7, wherein the amount of radicals generated by the radical irradiation device of a selected specific row unit from among the plurality of radical irradiation devices is greater than the amount of radicals generated by the radical irradiation devices of the other row units.

9. A sputtering apparatus according to claim 8, wherein the amount of radicals generated by the radical irradiation device of the other row unit is 30% or less of the amount of radicals generated by the radical irradiation device of the specific row unit.

10. A sputtering apparatus according to claim 8 or 9, wherein the radical irradiation device of the specific row unit selected from the plurality of radical irradiation devices is sequentially switched in the first direction.

11. A sputtering apparatus as described in claim 8 or 9, wherein the radical irradiation device of the specific row unit selected from the plurality of radical irradiation devices is sequentially switched in the first direction depending on the positional relationship between the substrate and the target in the first direction.

12. A sputtering apparatus as described in claim 11, wherein, when viewed from a third direction perpendicular to the first direction and the second direction, the target moves in the first direction through an area overlapping with the multiple radical irradiation devices, and, when viewed from the third direction, the radical irradiation devices in the specific row unit are selected to track the movement of the target.

13. A sputtering apparatus as described in claim 11, wherein, when viewed from a third direction perpendicular to the first direction and the second direction, the target moves in the first direction through a region that overlaps with the multiple radical irradiation devices, and the radical irradiation device in the specific row unit is selected so as to overlap with the target when viewed from the third direction.

14. The sputtering apparatus of claim 1, wherein the target is a planar target.

15. The sputtering apparatus of claim 1, wherein the target is a rotary target.

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