Film deposition apparatus and film deposition method

Abstract

To provide a film deposition apparatus and a film deposition method capable of depositing a film having a desired chemical composition in magnetron sputtering accompanied by chemical reactions with reactive gases.SOLUTION: A film deposition apparatus comprises a chamber, a plurality of magnets, a gas supply part, and a control part. The plurality of magnets are extended in a first direction parallel to a target surface and arrayed along a second direction parallel to the target surface and perpendicular to the first direction. The gas supply part supplies a reactive gas between the film deposition object and the target from both end sides in the second direction of the target. The control part switches between a first state where at least the magnet at the central part in the second direction of the plurality of magnets forms plasma of a sputter gas confined by a magnetic field and a second state where at least the magnet at the central part in the second direction of the plurality of magnets does not form the plasma.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a film formation apparatus and a film formation method using magnetron sputtering. [Background technology]

[0002] In sputtering, a sputtering gas introduced into a vacuum is turned into plasma by discharging the sputtering gas, and the generated ions collide with a target to generate sputtered particles, which are then deposited on the object to be deposited. Magnetron sputtering uses a magnet placed near the target to enclose electrons in a magnetic field, creating a high-density plasma region near the target, allowing ions to efficiently collide with the target, thereby enabling high-speed deposition (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-200520 Summary of the Invention [Problem to be solved by the invention]

[0004] In a magnetron sputtering apparatus such as that described in Patent Document 1, a reactive gas is sometimes supplied along with the sputtering gas to form a film while causing a chemical reaction in the target material. For example, if the target material is titanium (Ti), supplying N2 as the reactive gas will form a titanium nitride (TiN) film. In this case, if the concentration of the reactive gas is insufficient, a film with the desired chemical composition cannot be formed.

[0005] In view of the above circumstances, an object of the present invention is to provide a film formation apparatus and a film formation method that are capable of forming a film having a desired chemical composition in magnetron sputtering, which involves a chemical reaction with a reactive gas. [Means for solving the problem]

[0006] To achieve the above object, a film forming apparatus according to one aspect of the present invention includes a chamber, a plurality of magnets, a gas supply unit, and a control unit. The multiple magnets are positioned on the opposite side of the target to be film-formed within the chamber, having a target surface facing the target to be film-formed, and are extended in a first direction parallel to the target surface and arranged along a second direction parallel to the target surface and perpendicular to the first direction. The gas supply unit supplies a reactive gas between the film-forming object and the target from both end sides of the target in the second direction. The control unit switches between a first state in which at least one of the plurality of magnets located in the center in the second direction forms plasma of the sputtering gas confined by a magnetic field, and a second state in which at least one of the plurality of magnets located in the center in the second direction does not form the plasma.

[0007] The control unit may set a state in which all of the plurality of magnets generate the plasma as the first state, and a state in which none of the plurality of magnets generate the plasma as the second state.

[0008] The control unit may supply discharge power for converting the sputtering gas into plasma in the first state, and may not supply the discharge power in the second state.

[0009] The control unit may control the gas supply unit to supply or not supply the reactive gas in the first state, and to supply the reactive gas in the second state.

[0010] The control unit may define a state in which the central magnet among the plurality of magnets forms the plasma and the magnets at both ends do not form the plasma as the first state, and a state in which the magnets at both ends of the plurality of magnets form the plasma and the central magnet does not form the plasma as the second state.

[0011] The control unit may control the gas supply unit to supply the reactive gas in the first state and the second state.

[0012] The control unit may switch between the first state and the second state by moving the plurality of magnets along the second direction.

[0013] The control unit may switch between the first state and the second state by moving the plurality of magnets in a direction perpendicular to the first direction and the second direction.

[0014] In order to achieve the above object, one aspect of the present invention provides a film formation method for sputtering a film on a film formation target using a film formation apparatus including: a chamber; a target having a target surface facing the film formation target in the chamber, a plurality of magnets arranged on an opposite side of the film formation target from the target, the magnets extending in a first direction parallel to the target surface and arranged along a second direction parallel to the target surface and perpendicular to the first direction; and a gas supply unit that supplies a reactive gas between the film formation target and the target from both ends of the target in the second direction, The magnets are switched between a first state in which at least the central magnets in the second direction among the plurality of magnets form a magnetic field that confines the plasma of the sputtering gas at the target surface, and a second state in which at least the central magnets in the second direction among the plurality of magnets do not form a magnetic field that confines the plasma of the sputtering gas at the target surface. [Effects of the Invention]

[0015] As described above, according to the present invention, it is possible to provide a film formation apparatus and a film formation method capable of forming a film having a desired chemical composition in magnetron sputtering, which involves a chemical reaction with a reactive gas. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic diagram of a film forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram illustrating a partial configuration of the film forming apparatus. [Figure 3] FIG. 2 is a schematic diagram illustrating a partial configuration of the film forming apparatus. [Figure 4] FIG. 2 is a schematic diagram showing film formation by the film formation apparatus. [Figure 5] 2 is a schematic diagram showing film formation by the film formation apparatus. FIG. [Figure 6] FIG. 2 is a schematic diagram showing film formation by the film formation apparatus. [Figure 7] FIG. 2 is a schematic diagram of the film forming apparatus in a first state. [Figure 8] FIG. 4 is a schematic diagram illustrating another example of the first state of the film forming apparatus. [Figure 9] FIG. 4 is a schematic diagram illustrating another example of the second state of the film forming apparatus. [Figure 10] FIG. 4 is a schematic diagram illustrating another example of the first state of the film forming apparatus. [Figure 11] FIG. 4 is a schematic diagram illustrating another example of the second state of the film forming apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0018] [About the deposition equipment] A film formation apparatus according to this embodiment will be described. FIG. 1 is a schematic diagram of a film formation apparatus 100 according to this embodiment, and FIGS. 2 and 3 are schematic diagrams of a portion of the film formation apparatus 100. As shown in FIG. 1, the film formation apparatus 100 includes a vacuum chamber 101, a target 102, a backing plate 103, a magnet unit 104, an adhesion prevention plate 105, a gas supply unit 106, and a control unit 107. A film formation target 150 is disposed in the vacuum chamber 101. Hereinafter, the surface of the film formation target 150 will be referred to as a film formation target surface 150a.

[0019] Vacuum chamber 101 defines a sputtering space 111 therein. A gas supply unit 106 and an exhaust unit (not shown) are connected to vacuum chamber 101. Gas supply unit 106 supplies sputtering gas to sputtering space 111. The exhaust unit includes exhaust means such as a vacuum pump, and evacuates sputtering space 111 to a vacuum.

[0020] The target 102 is placed in the sputtering space 111 and generates sputtered particles. The target 102 is plate-shaped as shown in Fig. 2, and faces a film-forming target surface 150a of the film-forming target 150. Hereinafter, the surface of the target 102 facing the film-forming target surface 150a will be referred to as the target surface 102a, and the opposite surface will be referred to as the back surface 102b.

[0021] The target surface 102a is planar, and hereinafter, a direction parallel to the target surface 102a is referred to as the X direction, and a direction parallel to the target surface 102a and perpendicular to the X direction is referred to as the Y direction. The direction perpendicular to the X and Y directions is referred to as the Z direction. As shown in FIG. 2, the target 102 may be rectangular with the X direction as the short side direction and the Y direction as the long side direction, but may have other shapes. The material of the target 102 is not particularly limited, and may be titanium (Ti), molybdenum (Mo), aluminum (Al), copper (Cu), or the like.

[0022] The backing plate 103 is located on the back side of the target 102 and supports the target 102. Note that the backing plate 103 is not shown in Fig. 2. As shown in Fig. 1, the target 102 is fixed with its back surface 102b in contact with the backing plate 103. The backing plate 103 is conductive, is connected to a sputtering power supply 171, and functions as a cathode.

[0023] As shown in Fig. 3, the magnet unit 104 is disposed on the opposite side of the backing plate 103 from the target 102. The number of magnet units 104 is not particularly limited and can be determined according to the size of the film-forming target 150. As shown in Figs. 2 and 3, the magnet unit 104 includes a yoke 121 and magnets 122. The magnets 122 extend in the X direction and are arranged along the Y direction, forming a magnetic field on the target surface 102a.

[0024] Specifically, the magnet 122 includes an N-pole magnet 123 and an S-pole magnet 124, and as shown in FIG. 2, the N-pole magnet 123 surrounds the S-pole magnet 124. Note that the magnetic poles of the N-pole magnet 123 and the S-pole magnet 124 may be opposite. The magnet unit 104 is configured to be movable by a drive mechanism (not shown). The drive mechanism is not particularly limited, but may be, for example, a ball screw and its rotation drive source. As shown in FIG. 3, the distance between the magnet 122 and the target surface 102a is defined as distance L.

[0025] 1, the adhesion shield 105 is disposed between the target 102 and the inner wall of the vacuum chamber 101, and prevents sputtered particles from adhering to the inner wall of the vacuum chamber 101. The adhesion shield 105 may be made up of two members spaced apart as shown in FIG. 1, or may be made up of a single member. The adhesion shield 105 is connected to a sputtering power supply 171 and functions as an anode.

[0026] The gas supply unit 106 supplies sputtering gas from a gas source between the film-forming target 150 and the target 102 from both ends of the target 102 in the X direction, as shown by the dashed arrows in FIG. 1. This sputtering gas includes a sputtering gas and a reactive gas. The sputtering gas is a gas that is ionized by electrical discharge, such as argon (Ar). The reactive gas is a gas that chemically reacts with particles of the target material generated by the collision of the ions, such as nitrogen (N2).

[0027] 1, gas supply unit 106 is disposed on the rear side of adhesion prevention plate 105, and can supply sputtering gas (indicated by the arrow in the figure) between object 150 to be film-formed and target 102 through the gap in adhesion prevention plate 105. Gas supply unit 106 may also supply sputtering gas from another position, such as between adhesion prevention plate 105 and object 150 to be film-formed.

[0028] The control unit 107 includes a sputtering power supply 171, a magnet driving unit 172, and a gas control unit 173. The sputtering power supply 171 is a power supply for discharging power supplied between the anode and the cathode, and may be a DC (Direct Current) power supply, or a high frequency power supply such as an RF (Radio Frequency) power supply or a VHF (Very High Frequency) power supply.

[0029] The magnet driving unit 172 moves the position of the magnet unit 104. Specifically, the magnet driving unit 172 controls the rotation angle of the rotary drive source to operate the ball screw by a predetermined distance, thereby moving the position of the magnet unit 104. The magnet driving unit 172 may also move the position of the magnet unit 104 by other methods. Details of the operation of the magnet driving unit 172 will be described later. The gas control unit 173 is connected to the gas supply unit 106 and controls the supply of sputtering gas.

[0030] The film forming apparatus 100 has the above-described configuration. The film forming apparatus 100 may have other configurations instead of or in addition to the above-described configurations.

[0031] [Film formation method] A film formation method using the film formation apparatus 100 will be described. Figures 4 to 6 are schematic diagrams showing the film formation method using the film formation apparatus 100. In this film formation method, first, the sputtering space 111 is evacuated to a vacuum using an exhaust unit (not shown). After the sputtering space 111 is sufficiently depressurized, a sputtering gas (indicated by a dashed arrow in the figure) is supplied to the sputtering space 111 from the gas supply unit 106. Figure 4 schematically shows a reactive gas G contained in the sputtering gas.

[0032] Next, as shown in Fig. 5, while the magnet driving unit 172 oscillates each magnet unit 104 as indicated by the solid arrow, the sputtering power supply 171 starts to supply discharge power between the cathode (target 102, etc.) and the anode (adhesion shield 105). This discharge power converts the sputtering gas into plasma. This plasma is confined within the magnetic field generated by the magnet 122, and high-density plasma P is formed on the target surface 102a at a position close to each magnet unit 104, as shown in Fig. 5.

[0033] Ions forming the high-density plasma P collide with the target surface 102a, scattering sputter particles, which are particles of the target material. The scattered sputter particles react with the reactive gas G and are deposited on the film-forming target surface 150a, forming a film.

[0034] If the supply of discharge power continues in this state, the reactive gas G will be consumed by reaction with the sputtered particles. The supply of reactive gas G from the gas supply unit 106 (indicated by the dashed arrow in the figure) continues, but the newly supplied reactive gas G reacts with the sputtered particles at both ends in the X direction and is consumed. As a result, the newly supplied reactive gas G does not reach the center in the X direction. Therefore, as shown in FIG. 6, a high concentration of reactive gas G1 is distributed at both ends in the X direction, and a low concentration of reactive gas G2 is distributed in the center in the X direction.

[0035] As a result, a film of the target composition (e.g., TiN) is formed at both ends in the X direction of the film-forming target 150, but a film of a composition (e.g., Ti) lacking in reactive gas components is formed in the center in the X direction.

[0036] [Switching between the first and second states] In the film forming apparatus 100, the film formation can be performed while switching between the "first state" and the "second state" as described below, thereby solving the above-mentioned problems with the film composition.

[0037] Here, the first state is a state in which at least the magnets 122 in the center in the X direction among the magnets 122 generate high-density plasma P. On the other hand, the second state is a state in which at least the magnets 122 in the center in the X direction among the magnets 122 do not generate high-density plasma P.

[0038] 7 is a schematic diagram of the first state. In the first state, as shown in FIG. 7, discharge power is supplied between the cathode and the anode, and all the magnets 122 generate high-density plasma P. In addition, in the first state, the gas supply unit 106 stops supplying the sputtering gas. Alternatively, in the first state, the gas supply unit 106 may supply the sputtering gas.

[0039] On the other hand, in the second state, no discharge power is supplied between the cathode and the anode, and as shown in Fig. 4, none of the magnets 122 generate high-density plasma P. Also, in the second state, the gas supply unit 106 supplies a sputtering gas.

[0040] In the film formation process, the film formation apparatus 100 is first set to the second state (see FIG. 4), then switched to the first state (see FIG. 7), and the first state is maintained for a certain period of time. This period is, for example, one second. In the first state, sputtering progresses, and a reaction product of the sputtered particles and the reactive gas G is formed on the film formation target surface 150a. The period for maintaining the first state is preferably a period during which the reactive gas G1 reacts with the sputtered particles and is consumed, preventing high-concentration reactive gas G1 and low-concentration reactive gas G2 from being distributed at both ends and the center in the X direction. For example, a period of 0.4 seconds is preferable when the sputtering gas is a nitrogen / argon mixed gas (N2 / Ar ratio: 10%), and a period of 0.8 seconds is preferable when the sputtering gas is a nitrogen / argon mixed gas (N2 / Ar ratio: 100%).

[0041] Next, the film forming apparatus 100 is switched to the second state and maintained in the second state for a certain period of time. This period is preferably the time required for filling with reactive gas, e.g., 0.4 seconds. In the second state, sputtering gas is supplied from the gas supply unit 106, i.e., reactive gas G is supplied. Since sputtering is stopped in the second state, reactive gas G is not consumed, and a uniform concentration distribution of reactive gas G is achieved between the target 102 and the film forming object 150.

[0042] The film formation apparatus 100 is again switched to the first state (see FIG. 7), and a film is formed on the film formation target surface 150a. Thereafter, the second state and the first state are alternately repeated until a film of the desired thickness is formed on the film formation target 150. By forming the film in this manner, a difference in the concentration distribution of the reactive gas G (see FIG. 6) is not formed, and it is possible to form a film having a desired chemical composition.

[0043] [Other aspects of the first and second states] The first and second states described above can also be set as follows: Figure 8 is a schematic diagram of the first state, and Figure 9 is a schematic diagram of the second state.

[0044] As described above, the first state is a state in which at least the magnets 122 in the center in the X direction form high-density plasma P. Specifically, the first state can be a state in which the magnets 122 in the center in the X direction form high-density plasma P, and the magnets 122 at both ends in the X direction do not form high-density plasma P. More specifically, as shown in FIG. 8, the first state can be a state in which the magnet unit 104 is located in the center in the X direction, and the magnet units 104 are not located at both ends in the X direction. The number of magnet units 104 that form the first state is not limited to four, and may be one or more.

[0045] As described above, the second state is a state in which at least the magnets 122 in the center in the X direction do not generate high-density plasma P. Specifically, the second state can be a state in which the magnets 122 in the center in the X direction do not generate high-density plasma P, and the magnets 122 at both ends in the X direction generate high-density plasma P. More specifically, as shown in FIG. 9, the second state can be a state in which the magnet unit 104 is not located in the center in the X direction, and the magnet units 104 are located at both ends in the X direction. The number of magnet units 104 that form the second state is not limited to two each, and may be one or more.

[0046] The magnet driver 172 can switch between the first state and the second state by moving the magnet unit 104 along the X direction. Specifically, as shown in FIG. 8, the magnet driver 172 places the magnet unit 104 at the center in the X direction to set it to the first state. In this state, the magnet driver 172 oscillates the magnet unit 104 as shown by the arrow in FIG. 8, and film formation is performed. At this time, since the reactive gas G is not consumed at both ends in the X direction, a high concentration of reactive gas G is supplied to the center in the X direction. As a result, a reaction product of the sputtered particles and the reactive gas G is formed on the film formation target surface 150a at the center in the X direction.

[0047] After a predetermined period of film formation, the magnet driver 172 moves the magnet unit 104 along the X direction to both ends in the X direction, setting it to the second state as shown in FIG. 9. In this state, the magnet driver 172 oscillates the magnet unit 104 as shown by the arrows in FIG. 9, and film formation is further performed. During this process, reactive gas G is consumed at both ends in the X direction, but because reactive gas G is supplied from the gas supply unit 106, a high concentration of reactive gas G1 is distributed at both ends in the X direction. As a result, a reaction product of the sputtered particles and reactive gas G is formed on the film formation target surface 150a at both ends in the X direction.

[0048] Furthermore, after a predetermined period of film formation, the magnet driving unit 172 moves the magnet unit 104 along the X direction to the center in the X direction, thereby setting it to the first state as shown in Fig. 8. The reactive gas G supplied from the gas supply unit 106 is no longer consumed at both ends in the X direction, and reaches the center in the X direction as shown in Fig. 8, so that a reaction product of the sputtered particles and the reactive gas G is formed in the center.

[0049] Thereafter, the second state and the first state are alternately repeated until a film of the desired thickness is formed on the film-forming target 150. By performing film formation in this manner, film formation always proceeds at a position where the concentration of reactive gas G is high, making it possible to form a film having a desired chemical composition. Note that the order of the first state and the second state in film formation may be reversed, i.e., film formation may start from the second state.

[0050] Furthermore, the first state and the second state can also be set as follows. Fig. 10 is a schematic diagram of the first state, and Fig. 11 is a schematic diagram of the second state. As shown in Fig. 10, the first state can also be achieved by positioning the magnet units 104 facing both ends in the X direction farther away from the target 102 than the magnet unit 104 facing the center.

[0051] When the magnet unit 104 is moved away from the target 102, the magnetic field formed by the magnet 122 no longer reaches the target surface 102a, and the magnet 122 no longer functions as a magnet for generating high-density plasma P. As shown in the figure, the distance between the magnet 122 approaching the target 102 and the target surface 102a is set to distance L1, and the distance between the magnet 122 moved away from the target 102 and the target surface 102a is set to distance L2.

[0052] 11 is a schematic diagram of the second state. As shown in the figure, the second state can also be achieved by positioning the magnet unit 104 facing the center in the X direction farther from the target 102 than the magnet units 104 facing both ends. As in FIG. 10, the distance between the magnet 122 approaching the target 102 and the target surface 102a is set to distance L1, and the distance between the magnet 122 distant from the target 102 and the target surface 102a is set to distance L2.

[0053] In the first and second states, the distance L1 is preferably 100 mm or less, and the distance L2 is preferably 120 mm or more. If the distance L1 is 100 mm or less, a magnetic field is generated by the magnet 122 on the target surface 102 a, but if the distance L2 is 120 mm or more, a magnetic field is not generated by the magnet 122 on the target surface 102 a.

[0054] The magnet driving unit 172 can also switch between the first state and the second state by moving the magnet units 104 along the Z direction. Specifically, as shown in Fig. 10, the magnet driving unit 172 can bring the central magnet unit 104 closer to the target 102 and move the magnet units 104 at both ends away from the target 102 to establish the first state. The magnet driving unit 172 can also bring the central magnet unit 104 away from the target 102 and move the magnet units 104 at both ends closer to the target 102 to establish the second state.

[0055] In this case, as in the cases shown in Figures 8 and 9, film formation proceeds at positions where the concentration of reactive gas G is high in both the first and second states, making it possible to form a film having the desired chemical composition.

[0056] [Embodiments of the present invention] Although the embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to the above-described embodiments and various modifications can be made. At least two of the characteristic features described in the above-described embodiments can be arbitrarily combined. [Explanation of symbols]

[0057] 100...Film deposition equipment 101...Vacuum chamber 102...Target 103...Backing plate 104...Magnet unit 105…Adhesion prevention plate 106...Gas supply unit 107...Control unit 111...Sputter space 121…York 122...Magnet 123...North pole magnet 124…S pole magnet 150...Film formation target 171...Sputter power supply 172...Magnet drive unit 173...Gas control section

Claims

1. a chamber; a plurality of magnets disposed in the chamber on an opposite side of a target having a target surface facing the target, the magnets extending in a first direction parallel to the target surface and arranged along a second direction parallel to the target surface and perpendicular to the first direction; a gas supply unit that supplies a reactive gas between the film-forming object and the target from both end sides of the target in the second direction; a control unit that switches between a first state in which at least one of the plurality of magnets located at a center in the second direction forms plasma of the sputtering gas confined by a magnetic field, and a second state in which at least one of the plurality of magnets located at a center in the second direction does not form the plasma; A film forming apparatus comprising:

2. 2. The film forming apparatus according to claim 1, The control unit sets a state in which all of the plurality of magnets generate the plasma as the first state, and a state in which none of the plurality of magnets generate the plasma as the second state. Film deposition equipment.

3. 3. The film forming apparatus according to claim 2, The control unit supplies discharge power for converting the sputtering gas into plasma in the first state, and does not supply the discharge power in the second state. Film deposition equipment.

4. 3. The film forming apparatus according to claim 2, The control unit controls the gas supply unit to supply or not supply the reactive gas in the first state, and to supply the reactive gas in the second state. Film deposition equipment.

5. 2. The film forming apparatus according to claim 1, The control unit sets a state in which the central magnet among the plurality of magnets generates the plasma and the magnets at both ends do not generate the plasma as the first state, and sets a state in which the magnets at both ends among the plurality of magnets generate the plasma and the central magnet does not generate the plasma as the second state. Film deposition equipment.

6. 6. The film forming apparatus according to claim 5, The control unit controls the gas supply unit to supply the reactive gas in the first state and the second state. Film deposition equipment.

7. 6. The film forming apparatus according to claim 5, The control unit switches between the first state and the second state by moving the plurality of magnets along the second direction. Film deposition equipment.

8. 6. The film forming apparatus according to claim 5, The control unit switches between the first state and the second state by moving the plurality of magnets along a direction perpendicular to the first direction and the second direction. Film deposition equipment.

9. A film formation method for sputtering a film on a film-forming target using a film-forming apparatus including: a chamber; a target having a target surface facing the film-forming target in the chamber, a plurality of magnets arranged on an opposite side of the film-forming target from the film-forming target, the magnets extending in a first direction parallel to the target surface and arranged along a second direction parallel to the target surface and perpendicular to the first direction; and a gas supply unit that supplies a reactive gas between the film-forming target and the target from both ends of the target in the second direction, A first state is switched in which at least a central magnet in the second direction among the plurality of magnets forms a magnetic field that confines plasma of the sputtering gas on the target surface, and a second state is switched in which at least a central magnet in the second direction among the plurality of magnets does not form a magnetic field that confines plasma of the sputtering gas on the target surface. Film formation method.

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