Target for DLC film deposition

Abstract

A target for DLC (diamond-like carbon) film deposition comprises a disc-shaped body containing carbon. The body has a use surface that evaporates during film deposition. The diameter of the use surface is 50 to 150 (mm).

Description

DLC film deposition target

[0001] The disclosed embodiments relate to a target for DLC film formation.

[0002] Conventionally, a technique for forming a diamond-like carbon (DLC) thin film on the surface of an object such as a cutting tool has been disclosed. In this conventional technique, the DLC thin film can be formed on the object by a physical vapor deposition method such as an arc ion plating method (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2019-7058

[0004] A diamond-like carbon (DLC) film deposition target according to one embodiment includes a disk-shaped main body containing carbon. The main body has a usable surface that evaporates during film deposition. The diameter of the usable surface is 50 mm to 150 mm.

[0005] Fig. 1 is a schematic diagram showing an example of the configuration of a film forming apparatus according to an embodiment. Fig. 2 is a perspective view showing an example of the configuration of a target according to an embodiment. Fig. 3 is a cross-sectional view showing an example of the configuration of a target according to an embodiment. Fig. 4 is a cross-sectional view showing an example of a target attachment mechanism according to an embodiment. Fig. 5 is an enlarged cross-sectional view showing an example of the configuration of a target according to an embodiment. Fig. 6 is an enlarged cross-sectional view showing an example of the configuration of a target according to an embodiment. Fig. 7 is a cross-sectional view showing an example of a target configuration according to another embodiment.

[0006] Hereinafter, embodiments of a DLC film formation target disclosed in the present application will be described with reference to the accompanying drawings. Note that this disclosure is not limited to the embodiments described below. Furthermore, each embodiment can be appropriately combined within a range that does not cause contradictions in the processing content. Furthermore, the same components in each of the following embodiments are given the same reference numerals, and duplicated explanations will be omitted.

[0007] <Film Forming Apparatus> First, the configuration of a film forming apparatus 1 to which a target 33 according to an embodiment can be attached will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing an example of the configuration of the film forming apparatus 1 according to an embodiment.

[0008] As shown in FIG. 1, the film forming apparatus 1 according to the embodiment includes a chamber 10 , an exhaust unit 20 , an evaporation unit 30 , a workpiece holder 40 , and a gas supply unit 50 .

[0009] The chamber 10 is a container that accommodates a plurality of workpieces W. The workpieces W are, for example, cutting tools. Note that the workpieces W of the present disclosure are not limited to cutting tools. The exhaust unit 20 evacuates the interior of the chamber 10. The interior of the chamber 10 is maintained in a vacuum state by the exhaust unit 20.

[0010] Evaporation unit 30 evaporates target 33, which is a coating material. Evaporation unit 30 has an arc power supply unit 31, an arc cathode 32, and target 33. Arc power supply unit 31 is a power supply circuit that supplies a discharge current to arc cathode 32.

[0011] Arc cathode 32 holds target 33 and generates a vacuum arc discharge in chamber 10 using power supplied from arc power supply 31. Arc cathode 32 and target 33 are located, for example, on a side wall of chamber 10. Furthermore, a use surface 34a (see FIG. 2) of target 33 is exposed inside chamber 10 and is positioned so as to face multiple workpieces W.

[0012] When vacuum arc discharge is initiated by the evaporation unit 30, a molten region called an arc spot having a diameter of several μm is generated on the use surface 34 a of the target 33. A high-density current is concentrated in this arc spot, and the use surface 34 a of the target 33 is instantly melted and evaporated. This vacuum arc discharge forms a coating containing components of the target 33 on the surfaces of the multiple workpieces W.

[0013] 1 shows an example in which two pairs of arc power supply units 31, arc cathodes 32, and targets 33 are located in film formation apparatus 1, but the present disclosure is not limited to such an example. For example, film formation apparatus 1 may have one pair of arc power supply units 31, arc cathodes 32, and targets 33 located therein, or three or more pairs of arc power supply units 31, arc cathodes 32, and targets 33 located therein.

[0014] The workpiece holding unit 40 holds a plurality of workpieces W. The workpiece holding unit 40 has a first table 41, a plurality of second tables 42, a plurality of columnar portions 43, a drive unit 44, and a bias power supply unit 45.

[0015] The first table 41 is, for example, disk-shaped and rotatably supported at the bottom of the chamber 10. The second table 42 is, for example, disk-shaped and rotatably supported on the upper surface of the first table 41. The columnar portion 43 is, for example, column-shaped and rotatably supported on the upper surface of the second table 42, and supports a plurality of workpieces W.

[0016] The driving unit 44 rotates the first table 41 relative to the chamber 10. The driving unit 44 also rotates the second table 42 relative to the first table 41. The driving unit 44 also rotates the columnar portion 43 relative to the second table 42.

[0017] As a result, a coating containing components of the target 33 is formed approximately uniformly on the entire surface of all of the workpieces W supported by the multiple pillar-shaped portions 43. The bias power supply unit 45 applies a negative potential to the multiple workpieces W via the first table 41, the second table 42, and the pillar-shaped portions 43.

[0018] The gas supply unit 50 supplies a process gas for forming a coating inside the chamber 10. The gas supply unit 50 includes, for example, a plurality of mass flow controllers 51.

[0019] The film forming apparatus 1 also includes a control device 2. The control device 2 is, for example, a computer, and includes a control unit 3 and a storage unit 4. The storage unit 4 stores programs that control various processes executed in the film forming apparatus 1. The control unit 3 controls the operation of the film forming apparatus 1 by reading and executing the programs stored in the storage unit 4.

[0020] The program may be recorded on a computer-readable storage medium and installed from that storage medium into the storage unit 4 of the control device 2. Examples of computer-readable storage media include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical disk (MO), and a memory card.

[0021] Although not shown in FIG. 1, the film forming apparatus 1 according to the embodiment may be provided with a heating section for heating multiple workpieces W to a desired temperature, or an etching section for etching and cleaning the surface of the workpieces W using Ar plasma or the like.

[0022] <Details of the Target> Next, details of the target 33 according to the embodiment will be described with reference to Fig. 2 to Fig. 7. Fig. 2 is a perspective view showing an example of the configuration of the target 33 according to the embodiment, and Fig. 3 is a cross-sectional view showing an example of the configuration of the target 33 according to the embodiment. The target 33 is an example of a target for forming a DLC film.

[0023] 2, the target 33 according to the embodiment has a substantially disk-like shape and includes a main body 34 containing carbon (C). The main body 34 may be made of, for example, graphite.

[0024] In the embodiment, for example, Ar gas, hydrocarbon gas, or the like is supplied from the gas supply unit 50 (see FIG. 1) into the chamber 10 (see FIG. 1), and the carbon-containing usable surface 34a of the main body 34 is melted and evaporated, thereby forming a DLC thin film on the surface of the workpiece W (see FIG. 1).

[0025] 2, the main body 34 of the target 33 according to this embodiment has a use surface 34a and a back surface 34b. The use surface 34a is one of the main surfaces of the main body 34 and is positioned so as to face the multiple workpieces W in the film forming apparatus 1. The back surface 34b is the other main surface of the main body 34 and is positioned on the opposite side of the use surface 34a. Note that FIG. 3 shows a cross section including the center of the use surface 34a and the center of the back surface 34b.

[0026] The use surface 34a of the main body 34 according to the embodiment is, for example, substantially circular in a plan view and has a diameter L1 as shown in Fig. 3. The back surface 34b of the main body 34 according to the embodiment is, for example, substantially circular in a plan view and has a diameter L2. The target 33 is substantially disk-shaped, and Fig. 3 shows a cross section including the center of the use surface 34a and the center of the back surface 34b, so the diameters L1 and L2 are shown in Fig. 3. Alternatively, Fig. 3 may be rephrased as a cross section perpendicular to the outer edges of the two main surfaces (the use surface 34a and the back surface 34b) of the main body 34.

[0027] The main body 34 according to the embodiment has a first portion 34c and a second portion 34d. The first portion 34c is located on the use surface 34a side and has the same area as the use surface 34a in a plan view. The second portion 34d is located on the back surface 34b side and has the same area as the back surface 34b in a plan view.

[0028] In this embodiment, the diameter L1 of the use surface 34a may be 50 mm to 150 mm. By making the use surface 34a have a relatively large diameter L1 of 50 mm or more, a DLC thin film can be efficiently formed on multiple workpieces W located over a wide area inside the chamber 10.

[0029] Furthermore, by setting the diameter L1 of the use surface 34a to 150 mm or less, a substantially uniform magnetic field can be formed over the entire use surface 34a, making it possible to form a DLC thin film of a stable thickness on multiple workpieces W.

[0030] In addition, in the embodiment, the diameter L1 of the use surface 34a may be larger than the thickness D of the main body portion 34. That is, in the embodiment, the thickness D of the main body portion 34 may be smaller than the diameter L1 of the use surface 34a. In this way, by reducing the thickness D of the main body portion 34, the cooling efficiency of the use surface 34a is improved.

[0031] Furthermore, by reducing the thickness D of the main body 34, it is possible to form a substantially uniform magnetic field over the entire use surface 34a. Therefore, according to the embodiment, by making L1>D, the stability of the film formation process is improved.

[0032] In addition, in the embodiment, the area of ​​the rear surface 34b may be larger than the area of ​​the use surface 34a. For example, in the embodiment, the diameter L2 of the rear surface 34b may be larger than the diameter L1 of the use surface 34a.

[0033] As a result, the second portion 34d is larger than the first portion 34c in a plan view, and the peripheral edge of the second portion 34d protrudes laterally like a flange. That is, in this embodiment, by making the second portion 34d larger than the first portion 34c in a plan view, a protrusion 34d1 is formed in the second portion 34d. This allows the target 33 to be easily attached to the arc cathode 32, as shown in FIG. 4 .

[0034] 4 is a cross-sectional view showing an example of an attachment mechanism for the target 33 according to the embodiment. As shown in FIG. 4, in the embodiment, the target 33 can be attached to the arc cathode 32 using an attachment member 35 and a fixing member 36.

[0035] The mounting member 35 is, for example, ring-shaped and configured so that the first portion 34c of the main body 34 can be inserted inside and the protrusion 34d1 of the second portion 34d can be caught and stopped. The mounting member 35 also has a plurality of through holes 35a, into which the plurality of fixing members 36 can be inserted, respectively.

[0036] The fixing member 36 is, for example, a bolt, which can be inserted through the through hole 35 a and can be fixed (screwed) into a screw hole 32 b located on the surface 32 a of the arc cathode 32 .

[0037] In this manner, in the embodiment, the main body 34 of the target 33 has the protrusion 34 d 1 , so that the target 33 can be easily attached to the arc cathode 32 .

[0038] Returning to the description of Figure 3, in the embodiment, the thickness T2 of the second portion 34d of the main body portion 34 may be 2.1 (mm) to 3.5 (mm).

[0039] By making the thickness T2 of the second portion 34d 2.1 (mm) or more, the strength of the protrusion 34d1 in the second portion 34d is improved, and therefore the second portion 34d is less likely to be damaged when the target 33 is fixed using the mounting member 35 (see Figure 4) and the fixing member 36 (see Figure 4).

[0040] Furthermore, by setting the thickness T2 of the second portion 34d to 3.5 (mm) or less, the target 33 can be attached more easily.

[0041] In addition, in the embodiment, the ratio T1 / T2 of the thickness T1 of the first portion 34c to the thickness T2 of the second portion 34d of the main body 34 may be 6.4 or less. That is, in the embodiment, the ratio T2 / T1 of the thickness T2 to the thickness T1 may be 0.16 or more.

[0042] In this manner, by making the thickness T2 of the second portion 34d somewhat larger than the thickness T1 of the first portion 34c, the strength of the protrusion 34d1 of the second portion 34d is improved. Therefore, according to this embodiment, the second portion 34d is less likely to be damaged when the target 33 is fixed using the mounting member 35 (see FIG. 4) and the fixing member 36 (see FIG. 4).

[0043] 5 is an enlarged cross-sectional view showing an example of the configuration of the target 33 according to the embodiment. As shown in FIG. 5, in the embodiment, a corner 34d2 on the use surface 34a side of the protrusion 34d1 of the main body 34 and a corner 34d3 on the back surface 34b side of the protrusion 34d1 may both be chamfered. For example, in the embodiment, the corners 34d2 and 34d3 of the protrusion 34d1 may be rounded or C-shaped.

[0044] This makes it difficult for the corners 34d2 and 34d3 of the protrusion 34d1 to be damaged when the target 33 is fixed using the attachment member 35 (see FIG. 4) and the fixing member 36 (see FIG. 4).

[0045] In the embodiment, the chamfer width of the corner 34d2 on the use surface 34a side may be larger than the chamfer width of the corner 34d3 on the back surface 34b side. Here, the "chamfer width" refers to the width of the chamfered portion in the direction perpendicular to the thickness direction of the main body 34 (the left-right direction in FIG. 3) in the cross section shown in FIG.

[0046] Since Figure 3 is a cross section perpendicular to the outer edges of the two main surfaces (usable surface 34a and back surface 34b) of the main body portion 34, the "chamfer width" may be replaced with the width of the chamfered portion in a direction perpendicular to the outer edges of the two main surfaces (usable surface 34a and back surface 34b) when viewed in a plane of the main body portion 34.

[0047] This reduces the contact area between the target 33 and the mounting member 35, thereby reducing heat diffusion from the target 33 to the mounting member 35. Therefore, according to the embodiment, it is possible to reduce energy loss when forming a DLC thin film.

[0048] In addition, in the embodiment, the chamfer width of the corner 34d3 on the rear surface 34b side may be larger than the chamfer width of the corner 34d2 on the use surface 34a side.

[0049] This increases the contact area between the target 33 and the mounting member 35, allowing the target 33 to be stably fixed by the mounting member 35. Therefore, according to the embodiment, it is possible to reduce stress concentration on the target 33 due to the mounting member 35 when the target 33 is fixed.

[0050] In the example of Figure 5, an example is shown in which both corners 34d2 and 34d3 have a chamfered shape, but the present disclosure is not limited to such an example, and for example, either corner 34d2 or corner 34d3 may have a chamfered shape.

[0051] In the embodiment, the corner 34e located at the base end of the protrusion 34d1 between the first portion 34c and the second portion 34d may have an R-shaped curved surface, which makes it less likely for cracks to occur at the base end of the protrusion 34d1.

[0052] In the embodiment, the corners 34a1 located on the periphery of the use surface 34a may have a chamfered shape. For example, in the embodiment, the corners 34a1 may have an R-shape or a C-shape.

[0053] This makes it difficult for the worker to get injured when attaching the target 33. In addition, it is possible to reduce damage to the corners 34a1 of the use surface 34a due to thermal shock or the like.

[0054] In the embodiment, the chamfer width of the corner 34a1 may be smaller than the chamfer width of the corner 34d2 and the chamfer width of the corner 34d3. By reducing the chamfer width of the corner 34a1 in this manner, the target 33 can be manufactured more easily.

[0055] 6 is an enlarged cross-sectional view showing an example of the attachment mechanism of the target 33 according to the embodiment. In the embodiment, the distance δ1 between the outer surface of the first portion 34c and the inner surface of the attachment member 35 may be smaller than the distance δ2 between the outer surface of the protrusion 34d1 and the inner surface of the attachment member 35. This can reduce warping of the target 33 due to thermal expansion during use.

[0056] In addition, in the embodiment, the distance δ1 between the outer surface of the first portion 34c and the inner surface of the mounting member 35 may be greater than the distance δ2 between the outer surface of the protrusion 34d1 and the inner surface of the mounting member 35. This can reduce adhesion between the target 33 and the mounting member 35 caused by thermal expansion during use.

[0057] 4, the back surface 34b of the main body 34 may be cooled during film formation by contacting the front surface 32a of the arc cathode 32. This prevents the temperature of the use surface 34a of the main body 34 from rising excessively, making it possible to form DLC thin films with a consistent thickness on multiple workpieces W.

[0058] 4, a flow path may be located inside the arc cathode 32, and a cooling medium such as water may be passed through this flow path. This further reduces an excessive rise in temperature of the use surface 34a of the main body 34, making it possible to form DLC thin films with a more stable film thickness on multiple workpieces W.

[0059] 7 is a cross-sectional view showing an example of the configuration of a target 33 according to another embodiment. As shown in FIG. 7, in this another embodiment, a central portion 34a2 of a use surface 34a of a main body 34 may be recessed with respect to an outer periphery 34a3 of the use surface 34a.

[0060] Generally, the use surface 34a of the main body 34 gradually lowers from the position at the start of use because, as described above, when a coating containing the components of the target 33 is formed on the surface of the workpiece W, the use surface 34a melts and evaporates due to the vacuum arc discharge.

[0061] Generally, the use surface 34a does not necessarily wear down evenly across the entire surface, but rather the central portion 34a2 wears down more than the peripheral portion 34a3. After some time has passed since the start of use of the target 33, when the central portion 34a2 has become recessed, the DLC thin film deposition process may become stable.

[0062] Therefore, in another embodiment, as shown in FIG. 7, by making the central portion 34a2 recessed from the start of use, the DLC thin film deposition process becomes stable from the start of use.

[0063] In another embodiment, the bottom surface of the central portion 34a2 may be flat, which stabilizes the movement of the arc spot and makes it easier for the arc discharge to occur uniformly.

[0064] Therefore, according to another embodiment, a DLC thin film can be stably formed, which makes it easier to consume the target 33 efficiently. Note that the bottom surface does not necessarily have to be flat in the strict sense. It is sufficient that the surface roughness Ra (arithmetic mean roughness) of the bottom surface is approximately 50 μm or less. The surface roughness Ra can be evaluated based on JIS B 0601:2013.

[0065] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0066] For example, in the above embodiment, an example has been shown in which the technology of the present disclosure is applied to the film-forming apparatus 1 that forms a DLC thin film by an arc ion plating method, but the present disclosure is not limited to such an example. For example, the technology of the present disclosure may be applied to a film-forming apparatus that forms a DLC thin film by various film-forming methods (such as a sputtering method).

[0067] Furthermore, in the above embodiment, an example has been shown in which the flange-shaped protrusion 34d1 is formed on the target 33, making the back surface 34b larger than the use surface 34a, but the present disclosure is not limited to such an example.

[0068] For example, the target 33 may have a generally trapezoidal cross section, so that the back surface 34b is larger than the use surface 34a. This also allows the attachment member 35 to be hooked onto the side surface of the trapezoid, making it possible to fix the target 33 to the arc cathode 32 without any problems.

[0069] Further advantages and other aspects may readily occur to those skilled in the art. Therefore, the disclosure in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

[0070] The present technology can also be configured as follows. (1) A DLC (diamond-like carbon) film deposition target comprising a disk-shaped main body containing carbon, the main body having a use surface that evaporates during film deposition, and the diameter of the use surface is 50 (mm) to 150 (mm). (2) The DLC film deposition target according to (1), in which the thickness of the main body is smaller than the diameter of the use surface. (3) The DLC film deposition target according to (1) or (2), in which the main body has a back surface opposite the use surface, and the area of ​​the back surface is larger than the area of ​​the use surface. (4) The DLC film deposition target according to (3), in which the main body has a first portion having the same area as the use surface in a plan view and a second portion having the same area as the back surface in a plan view, and the thickness T2 of the second portion is 2.1 (mm) to 3.5 (mm). (5) The DLC film deposition target according to (4), wherein T1 / T2 is 6.4 or less, where T1 is the thickness of the first portion. (6) The DLC film deposition target according to (4) or (5), wherein the second portion has a protruding portion protruding laterally, and a corner of the protruding portion has a chamfered shape. (7) The DLC film deposition target according to (6), wherein the chamfer width of the corner on the use surface side is larger than the chamfer width of the corner on the back surface side. (8) The DLC film deposition target according to (6), wherein the chamfer width of the corner on the back surface side is larger than the chamfer width of the corner on the use surface side. (9) The DLC film deposition target according to any one of (6) to (8), wherein a corner located at a base end of the protruding portion between the first portion and the second portion has an R-shaped curved surface. (10) The DLC film deposition target according to any one of (6) to (9), wherein the corners located on the peripheral edge of the use surface have a chamfered shape. (11) The DLC film deposition target according to (10), wherein the chamfer width of the corners located on the peripheral edge of the use surface is smaller than the chamfer width of the corners of the protrusions.(12) The DLC film deposition target according to any one of (6) to (11), wherein the distance between the outer surface of the first portion and the inner surface of a mounting member that fixes the main body to a film deposition apparatus is smaller than the distance between the outer surface of the protruding portion and the inner surface of the mounting member. (13) The DLC film deposition target according to any one of (6) to (11), wherein the distance between the outer surface of the first portion and the inner surface of a mounting member that fixes the main body to a film deposition apparatus is larger than the distance between the outer surface of the protruding portion and the inner surface of the mounting member. (14) The DLC film deposition target according to any one of (3) to (13), wherein the back surface is cooled during film deposition. (15) The DLC film deposition target according to any one of (1) to (14), wherein the central portion of the use surface is recessed with respect to the outer periphery of the use surface. (16) The DLC film deposition target according to (15), wherein the bottom surface of the central portion of the use surface is flat.

[0071] REFERENCE SIGNS LIST 1 Film forming device 2 Control device 33 Target (an example of a DLC film forming target) 34 Main body 34a Usable surface 34a1 Corner 34a2 Central portion 34a3 Outer periphery 34b Back surface 34c First portion 34d Second portion 34d1 Protruding portion 34d2, 34d3 Corner 34e Corner L1, L2 Diameter T1, T2 Thickness δ1, δ2 Distance

Claims

1. It has a disc-shaped body containing carbon, The main body has a working surface that evaporates during film formation, The diameter of the aforementioned work surface is 50 mm to 150 mm. Target for DLC (diamond-like carbon) film deposition.

2. The thickness of the main body is smaller than the diameter of the working surface. A DLC film deposition target according to claim 1.

3. The main body has a back surface opposite to the surface used, The area of ​​the back surface is larger than the area of ​​the surface used. A DLC film deposition target according to claim 1.

4. The main body portion has a first portion that has the same area as the surface used when viewed from above, and a second portion that has the same area as the back surface when viewed from above. The thickness T2 of the second part is 2.1 mm to 3.5 mm. A DLC film deposition target according to claim 3.

5. When the thickness of the first part is T1, T1 / T2 is 6.4 or less. A DLC film deposition target according to claim 4.

6. The second portion has a projection that protrudes laterally, The corners of the protruding portion have a chamfered shape. A DLC film deposition target according to claim 4.

7. The chamfer width of the corner on the working surface is greater than the chamfer width of the corner on the back surface. A DLC film deposition target according to claim 6.

8. The chamfer width of the corner on the back side is greater than the chamfer width of the corner on the work side. A DLC film deposition target according to claim 6.

9. The corner located at the base end of the protrusion between the first and second portions has an R-shaped curved surface. A DLC film deposition target according to any one of claims 6 to 8.

10. The corners located at the periphery of the surface being used have a chamfered shape. A DLC film deposition target according to any one of claims 6 to 8.

11. The chamfer width of the corner located at the periphery of the working surface is smaller than the chamfer width of the corner of the protruding portion. A DLC film deposition target according to claim 10.

12. The distance between the outer surface of the first portion and the inner surface of the mounting member that fixes the main body to the film deposition apparatus is smaller than the distance between the outer surface of the protruding portion and the inner surface of the mounting member. A DLC film deposition target according to any one of claims 6 to 8.

13. The distance between the outer surface of the first portion and the inner surface of the mounting member that fixes the main body to the film-forming apparatus is greater than the distance between the outer surface of the protruding portion and the inner surface of the mounting member. A DLC film deposition target according to any one of claims 6 to 8.

14. The aforementioned back surface is cooled during film formation. A DLC film deposition target according to any one of claims 3 to 8.

15. The central part of the work surface is recessed relative to the outer periphery of the work surface. A DLC film deposition target according to any one of claims 1 to 8.

16. The bottom surface of the central part of the usage surface is flat. A DLC film deposition target according to claim 15.