Member for plasma processing device, and method for manufacturing member for plasma processing device

Abstract

A member for a plasma processing device, the member including a base material, an intermediate layer other than an ALD layer that covers a part or all of the base material, and the ALD layer that continuously covers a surface of the intermediate layer, the intermediate layer not having an exposed surface. A method for manufacturing a member for a plasma processing device, the method including: (A) a step of forming an intermediate layer covering a part or all of a base material, the intermediate layer including a film formed using a manufacturing method other than an ALD method; (B) a step of heat-treating the intermediate layer to remove moisture contained in the intermediate layer; and (C) a step of forming an ALD layer covering the entirety of an exposed surface of the intermediate layer.

Description

Member for plasma processing apparatus and method for manufacturing member for plasma processing apparatus

[0001] The present application claims priority to Japanese Patent Application No. 2024-073617, filed April 30, 2024, and incorporates by reference all of the contents of said Japanese application.

[0002] Plasma etching equipment used in semiconductor manufacturing processes processes wafer surfaces using RF plasma generated in a chamber. Therefore, components installed in the chamber are generally coated with ceramic coatings that are highly resistant to plasma. Methods for forming ceramic coatings include thermal spraying.

[0003] Thermal spray coatings have pores within them, which allows plasma to penetrate through the pores, resulting in selective corrosion. To address this issue, it has been proposed to form a dense ALD film on a porous coating such as a thermal spray coating, thereby sealing the pores within the film (see Patent Documents 1 to 4).

[0004] Japanese Patent Application Laid-Open No. 2007-005545 Japanese Patent Application Laid-Open No. 2018-506859 Japanese Patent Application Laid-Open No. 2021-531410 Japanese Patent Application Laid-Open No. 2023-123461

[0005] Porous coatings, such as thermal spray coatings, can trap moisture from the atmosphere in the pores and remain there. If the moisture contained in the pores of the coating is released into the plasma processing space during the etching process, it can have adverse effects on the plasma, such as a drop in plasma temperature, and can also cause problems such as an increase in seasoning time (the time required to stabilize the RF plasma).

[0006] Under these circumstances, an object of the present invention is to provide a member for a plasma device that can avoid problems such as adverse effects on the plasma (such as a decrease in plasma temperature) and an increase in seasoning time (the time required to stabilize the RF plasma).

[0007] A member for a plasma processing apparatus according to one aspect of the present invention includes a substrate; an intermediate layer other than an ALD layer covering part or all of the substrate; and an ALD (Atomic Layer Deposition) layer continuously covering a surface of the intermediate layer, wherein the intermediate layer has no exposed surface.

[0008] A method for manufacturing a member for a plasma processing apparatus according to one embodiment of the present invention includes the steps of: (A) forming an intermediate layer covering a part or all of a substrate, the intermediate layer including a film formed by a manufacturing method other than the ALD method; (B) heat-treating the intermediate layer to remove moisture contained in the intermediate layer; and (C) forming an ALD layer covering the entire exposed surface of the intermediate layer.

[0009] According to an aspect of the present invention, a member for a plasma processing apparatus can be provided that includes a base material, an intermediate layer, and an ALD layer, and the intermediate layer does not contain moisture or, even if it contains moisture, does not release it to the outside.

[0010] FIG. 1 is a schematic diagram of a plasma etching apparatus 10. FIG. 2 is a diagram illustrating the coating configuration of a member provided in the plasma etching apparatus 10. FIG. 3 is a schematic diagram illustrating the configuration of a member for a plasma processing apparatus according to an embodiment of the present invention. FIG. 4 is a schematic diagram illustrating the configuration of a member for a plasma processing apparatus according to an embodiment of the present invention. FIG. 5 is a schematic diagram illustrating the configuration of a member for a plasma processing apparatus according to an embodiment of the present invention. FIG. 6 is a schematic diagram illustrating the configuration of a member for a plasma processing apparatus according to an embodiment of the present invention. FIG. 7 is a process diagram of a method for manufacturing a member for a plasma processing apparatus according to an embodiment of the present invention. FIG. 8 is a cross-sectional SEM photograph of an example in which an ALD layer is formed on a thermal spray coating. FIG. 9 is a process diagram of a method for manufacturing a member for a plasma processing apparatus according to an embodiment of the present invention. FIG. 10 is a process diagram of a method for manufacturing a member for a plasma processing apparatus according to an embodiment of the present invention. FIG. 11 is a process diagram of a method for manufacturing a member for a plasma processing apparatus according to an embodiment of the present invention.

[0011] <Outline of Embodiments of the Present Invention> The outline of the embodiments of the present invention will be described below. (1) A member for a plasma processing apparatus according to an embodiment of the present invention includes a substrate, an intermediate layer other than an ALD layer covering a part or all of the substrate, and an ALD (Atomic Layer Deposition) layer continuously covering a surface of the intermediate layer, wherein the intermediate layer has no exposed surface.

[0012] According to the above-described plasma processing apparatus member, the surface of the intermediate layer is continuously covered with the ALD layer so as to have no exposed surface. The ALD layer is a film produced using atomic layer deposition (ALD), and is a very dense film without pinholes. Because the ALD layer is a dense film, even if the intermediate layer has pores and moisture is contained in the pores, the moisture is not released from the pores of the intermediate layer. Furthermore, the ALD layer is a dense film with almost no pores, and moisture is not released from the ALD layer. Furthermore, since the ALD layer is provided, new moisture is not taken into the pores of the intermediate layer. Therefore, according to a plasma processing apparatus using the above-described plasma processing apparatus member, it is possible to suppress the release of moisture from the plasma processing apparatus member into the processing space where plasma is generated, which would adversely affect the plasma and lengthen the seasoning time.

[0013] (2) In the member for a plasma processing apparatus described in (1) above, the ALD layer preferably has a thickness of 0.05 μm or more and 1.0 μm or less.

[0014] (3) In the member for a plasma processing apparatus according to (1) or (2) above, the intermediate layer preferably has a thickness of 1 μm or more and 500 μm or less.

[0015] (4) In the member for a plasma processing apparatus according to any one of (1) to (3) above, the ALD layer preferably contains at least one of an oxide, a fluoride, and an oxyfluoride containing at least one element selected from the group consisting of rare earth metals, Mg, Al, Si, Ca, Ti, Ta, and Zr.

[0016] (5) In the member for a plasma processing apparatus according to any one of (1) to (4) above, the intermediate layer is preferably a thermal spray layer, a PVD layer, a CVD layer, an anodized layer, or a multilayer including at least one of these.

[0017] (6) In the member for a plasma processing apparatus according to any one of (1) to (5) above, the ALD layer preferably covers the surface of the substrate continuously, and the substrate has no exposed surface.

[0018] (7) A method for manufacturing a member for a plasma processing apparatus according to an embodiment of the present invention includes the steps of: (A) forming an intermediate layer covering a part or all of a substrate, the intermediate layer including a film formed by a manufacturing method other than the ALD method; (B) heat-treating the intermediate layer to remove moisture contained in the intermediate layer; and (C) forming an ALD layer covering the entire exposed surface of the intermediate layer.

[0019] In the method for manufacturing the member for a plasma processing apparatus, a heat treatment step (B) is performed to remove moisture contained in the intermediate layer, followed by a step (C) of forming an ALD layer that covers the entire exposed surface of the intermediate layer. In this case, the manufactured member for a plasma processing apparatus has a moisture-free intermediate layer coated with a dense ALD layer, so that the pores of the intermediate layer remain moisture-free. Therefore, a plasma processing apparatus using the member for a plasma processing apparatus can prevent moisture from being released from the member for a plasma processing apparatus into the processing space where plasma is generated, which would adversely affect the plasma and prolong the seasoning time.

[0020] (8) In the method for manufacturing a member for a plasma processing apparatus according to (7) above, the heat treatment is preferably a vacuum heat treatment.

[0021] (9) In the method for manufacturing a member for a plasma processing apparatus according to (7) or (8) above, the heat treatment is preferably carried out under conditions of 100 Pa or less, 80° C. or more, and for 1 hour or more.

[0022] <Details of the Embodiments of the Present Invention> Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments of the present invention are not limited to the following embodiments. The members for a plasma processing apparatus according to the embodiments of the present invention are, for example, an electrostatic chuck, an upper disk, an outermost ring, an electrostatic chuck outer ring, an exhaust ring, and the like that constitute a plasma etching apparatus, which is an example of a plasma processing apparatus. Here, the plasma etching apparatus will be described first, and then specific examples of the members for a plasma processing apparatus that constitute each part of the plasma etching apparatus will be described.

[0023] (Plasma Etching Apparatus) Fig. 1 is a schematic diagram of a plasma etching apparatus 10. The plasma etching apparatus 10 is an etching apparatus that uses capacitively coupled plasma (CCP). Therefore, it is provided with an upper electrode 40 as an upper disk. In addition, a base 21 that constitutes an electrostatic chuck 20 also functions as a lower electrode.

[0024] The plasma etching apparatus 10 includes an electrostatic chuck 20, an upper electrode 40, an outermost ring 11, an electrostatic chuck outer ring 60, and an exhaust ring 70. The outermost ring 11 is a member for confining plasma gas and has a substantially cylindrical shape. The outermost ring 11 includes, for example, an aluminum alloy as a base material. The outermost ring 11 is grounded.

[0025] The electrostatic chuck 20 is provided inside the outermost ring 11. The electrostatic chuck 20 is supported by an electrostatic chuck support base (not shown). The electrostatic chuck 20 is a component that holds a silicon wafer (not shown) (hereinafter simply referred to as a wafer) on its upper surface. The wafer is loaded into the outermost ring 11 using a transfer arm (not shown), subjected to plasma etching processing, and then unloaded from the outermost ring 11. For this purpose, the outermost ring 11 is provided with an openable / closable loading / unloading port 13.

[0026] The electrostatic chuck 20 has an insulating layer 23 provided on a base 21, and an attraction electrode 25 provided on the insulating layer 23. A dielectric layer 24 is provided on the attraction electrode 25.

[0027] The base 21 has a generally circular disk shape with a step on a portion of its outer periphery. The power supply terminal component 30 is incorporated into the base 21. The base 21 serves as a base for the chucking electrode 25 and other components. The base 21 also functions as a lower electrode. The base 21 may be made of, for example, an aluminum alloy.

[0028] The attraction electrode 25 is provided on the base 21 so as to be sandwiched between an insulating layer 23 and a dielectric layer 24. The attraction electrode 25 is a conductive layer. The attraction electrode 25 is connected to a DC power supply 26 via a power supply terminal component 30 and a switch 27. When the switch 27 is turned on, the attraction electrode 25 generates an electrostatic force such as Coulomb force, thereby enabling electrostatic attraction of the wafer. In other words, the electrostatic chuck 20 can hold the wafer by electrostatic force.

[0029] The film thickness of the attraction electrode 25 is, for example, 2 μm or more and 1000 μm or less. If it is less than 2 μm, there is a risk that the film formation will be unstable. Furthermore, since there is no functional difference depending on the film thickness of the attraction electrode 25, from an economical point of view, it is preferable that the film thickness of the attraction electrode 25 be 1000 μm or less.

[0030] The thickness of the insulating layer 23 is, for example, 50 μm or more and 2000 μm or less. The heat removal efficiency can be adjusted by changing the thickness of the insulating layer 23. The thickness of the dielectric layer 24 is 50 μm or more and 1000 μm or less. The chucking force can be adjusted by changing the thickness of the dielectric layer 24.

[0031] The power supply terminal part 30 includes a power supply member 31 and an insulating member 33. The power supply member 31 is a substantially cylindrical member and is conductive.

[0032] The insulating member 33 is a substantially cylindrical member fixed to the outside of the power supply member 31. The insulating member 33 is provided so that the power supply member 31 does not come into contact with the base 21.

[0033] One or both of a heater (heat generating element) and a coolant flow path (neither of which is shown) may be provided inside the electrostatic chuck 20. By providing these, the temperature of the electrostatic chuck 20 and the temperature of the wafer held by the electrostatic chuck 20 can be adjusted.

[0034] The electrostatic chuck 20 may be provided with a gas supply line (not shown) that penetrates the electrostatic chuck 20 in the thickness direction. The gas supply line may be configured to be able to supply a heat transfer gas, such as He gas, between the upper surface of the electrostatic chuck 20 and the back surface of the wafer.

[0035] An electrostatic chuck outer periphery ring 60 is provided on the outer periphery of the base 21 of the electrostatic chuck 20. The electrostatic chuck outer periphery ring 60 is a substantially annular member that is fixed to the side surface of the base 21. The electrostatic chuck outer periphery ring 60 is a member that confines the plasma gas and protects the outer periphery of the electrostatic chuck 20.

[0036] An exhaust ring 70 is provided outside the lower part of the electrostatic chuck outer ring 60. The exhaust ring 70 is a substantially annular member, and its inner peripheral surface is fixed to the lower part of the electrostatic chuck outer ring 60 and its outer peripheral surface is fixed to the lower part of the outermost ring 11. The exhaust ring 70 has gas holes (not shown). The plasma etching apparatus 10 exhausts plasma gas to the outside of the processing space 17 through these gas holes.

[0037] The plasma etching apparatus 10 includes an upper electrode 40. The upper electrode 40 is disposed above the electrostatic chuck 20 so as to face the electrostatic chuck 20. A processing space 17 for performing plasma processing on a wafer is provided between the electrostatic chuck 20 and the upper electrode 40.

[0038] The upper electrode 40 is supported on the upper part of the outermost ring 11. The upper electrode 40 has an electrode plate 42 and an electrode support 44. The electrode plate 42 faces the processing space 17. The electrode plate 42 has a plurality of gas discharge holes 46c that form a gas flow path 46. In the plasma etching apparatus 10, a plasma generating gas is supplied to the processing space 17 through the gas discharge holes 46c.

[0039] The electrode support 44 is a component that supports the electrode plate 42. The electrode plate 42 is detachably attached to the electrode support 44. Examples of materials for the electrode plate 42 include a conductive member such as an aluminum alloy.

[0040] The upper electrode 40 has a gas flow path 46 therein through which a plasma generation gas flows. The gas flow path 46 includes a gas diffusion chamber 46a provided in the electrode support 44 and a plurality of gas flow holes 46b extending from the gas diffusion chamber 46a to the gas discharge holes 46c. The gas diffusion chamber 46a is connected to an external gas supply pipe 48.

[0041] The plasma etching apparatus 10 includes a first high frequency power supply 51 and a second high frequency power supply 52. ​​The first high frequency power supply 51 is connected to the base 21 via a matcher 53 and is a power supply that generates a first high frequency power for generating plasma. The first high frequency power supply 51 may also be connected to the upper electrode 40 via a matcher. The second high frequency power supply 52 is connected to the base 21 via a matcher 54 and is a power supply that generates a second high frequency power, i.e., a high frequency bias power, for attracting ions to the wafer.

[0042] In this plasma etching apparatus 10, a plasma generating gas is supplied from a gas supply device (not shown) through a gas supply pipe 48 and a gas flow path 46 to the processing space 17. At this time, the processing space 17 is depressurized to a predetermined pressure by an exhaust device (not shown). In addition, a high frequency electric field generated by high frequency power supplied from a first high frequency power supply 51 generates plasma within the outermost ring 11. In the plasma etching apparatus 10, the generated plasma is used to etch a wafer.

[0043] The plasma etching apparatus 10 is an etching apparatus using capacitively coupled plasma (CCP). Therefore, it has an upper electrode 40 as an upper disk, and the base 21 of the electrostatic chuck 20 functions as a lower electrode. On the other hand, a plasma etching apparatus using the plasma processing apparatus components according to the embodiment of the present invention may also be an etching apparatus using inductively coupled plasma (ICP). In this case, a ceramic sintered body is used as the base material of the upper disk to protect a high-frequency coil (not shown) installed above the upper disk. Furthermore, the base 21 does not necessarily function as a lower electrode. Therefore, the base material used as the base 21 of an etching apparatus using inductively coupled plasma (ICP) may be a ceramic sintered body instead of an aluminum alloy.

[0044] The member for a plasma processing apparatus according to the embodiment of the present invention can be used as the electrostatic chuck 20, the upper disk of the upper electrode 40 or the like, the outermost ring 11, the electrostatic chuck outer ring 60, and the exhaust ring 70 that constitute the plasma etching apparatus 10. Hereinafter, a coating configuration will be described when the member for a plasma processing apparatus according to the embodiment of the present invention is used as the electrostatic chuck 20, the upper electrode 40, the outermost ring 11, the electrostatic chuck outer ring 60, and the exhaust ring 70.

[0045] FIG. 2 is a diagram illustrating the coating configuration of components included in the plasma etching apparatus 10. In the present embodiment, the term "exposed surface" refers to a surface that is not in contact with other components. In the following description, the exposed surface of the intermediate layer and the exposed surface of the substrate refer to the surface prior to the formation of the ALD layer. The electrostatic chuck 20 includes a substrate 110A having a generally circular disk shape with a step on a portion of its outer circumferential surface (above the outer circumferential surface), a first intermediate layer 120A covering a portion of the bottom surface and side surfaces of the substrate 110A, a second intermediate layer 130A covering the remaining portion of the top surface and side surfaces of the substrate 110A, and an ALD layer 140A continuously covering the entire exposed surfaces of the first intermediate layer 120A and the second intermediate layer 130A. As a result, in the electrostatic chuck 20, the first intermediate layer 120A and the second intermediate layer 130A do not have exposed surfaces.

[0046] In the electrostatic chuck 20 , the substrate 110 A is composed of a base 21 , and the second intermediate layer 130 A is composed of an insulating layer 23 , a dielectric layer 24 and an attraction electrode 25 .

[0047] The upper electrode 40 is composed of a substrate 110B having a generally disk-shaped surface with a step on part of its outer circumferential surface (below the outer circumferential surface), a first intermediate layer 120B covering the upper surface and part of the side surface of the substrate 110B, a second intermediate layer 130B covering the lower surface and part of the remaining side surface of the substrate 110B, and an ALD layer 140B continuously covering the entire exposed surfaces of the first intermediate layer 120B and the second intermediate layer 130B. As a result, in the upper electrode 40, the first intermediate layer 120B and the second intermediate layer 130B have no exposed surfaces.

[0048] In the upper electrode 40 , the substrate 110 B is composed of an electrode plate 42 and an electrode support 44 .

[0049] The outermost ring 11 is composed of a substrate 110C having a substantially circular ring shape, a first intermediate layer 120C covering the outer peripheral surface, top surface, and bottom surface of the substrate 110C, a second intermediate layer 130C covering the inner peripheral surface of the substrate 110C, and an ALD layer 140C continuously covering the entire exposed surfaces of the first intermediate layer 120C and the second intermediate layer 130C. As a result, in the outermost ring 11, the first intermediate layer 120C and the second intermediate layer 130C have no exposed surfaces.

[0050] The electrostatic chuck outer ring 60 is composed of a substrate 110D having a substantially annular shape, a first intermediate layer 120D covering the inner peripheral surface of the substrate 110D, a second intermediate layer 130D covering the outer peripheral surface, top surface, and bottom surface of the substrate 110D, and an ALD layer 140D continuously covering the entire exposed surfaces of the first intermediate layer 120D and the second intermediate layer 130D. As a result, in the electrostatic chuck outer ring 60, the first intermediate layer 120D and the second intermediate layer 130D have no exposed surfaces.

[0051] The exhaust ring 70 is composed of a substrate 110E having a substantially circular ring shape, a first intermediate layer 120E covering the bottom surface, inner peripheral surface, and outer peripheral surface of the substrate 110E, a second intermediate layer 130E covering the top surface of the substrate 110E, and an ALD layer 140E continuously covering the entire exposed surfaces of the first intermediate layer 120E and the second intermediate layer 130E. As a result, in the exhaust ring 70, the first intermediate layer 120E and the second intermediate layer 130E have no exposed surfaces.

[0052] In each of the members having such a configuration, the substrate material is, for example, an aluminum alloy, the first intermediate layer is, for example, an anodized layer (anodized aluminum layer), and the second intermediate layer is, for example, a thermal spray layer, a PVD (Physical Vapor Deposition) layer, or a CVD (Chemical Vapor Deposition) layer.

[0053] 2 has a configuration in which the entire surface of the substrate is covered with either the first intermediate layer or the second intermediate layer, and further, the entire exposed surfaces of the first intermediate layer and the second intermediate layer are continuously covered with an ALD layer. However, the configuration of the member for a plasma processing apparatus according to the embodiment of the present invention is not limited to this configuration.

[0054] 3 to 6 are schematic diagrams showing the configuration of a member for a plasma processing apparatus according to an embodiment of the present invention. In the member for a plasma processing apparatus 200 shown in FIG. 3, an intermediate layer 220 is laminated on a portion of the surface of a substrate 210, and an ALD layer 240 is further laminated so as to cover the entire exposed surface of the intermediate layer 220 and a portion of the exposed surface of the substrate 210. The ALD layer 240 is formed continuously so that the entire layer is connected. As a result, in the member for a plasma processing apparatus 200, the intermediate layer 220 does not have an exposed surface.

[0055] 4, an intermediate layer A320 is laminated on a portion of the surface of a substrate 310, an intermediate layer B330 is further laminated on the intermediate layer A320, and an ALD layer 340 is further laminated so as to cover the entire exposed surfaces of the intermediate layers A320 and B330 and a portion of the exposed surface of the substrate 310. The ALD layer 340 is formed continuously so that the entire layer is connected. As a result, in the member 300 for a plasma processing apparatus, the intermediate layers A320 and B330 do not have exposed surfaces.

[0056] 5, an intermediate layer 420 is laminated on a portion of the surface of a substrate 410, and an ALD layer 440 is further laminated so as to cover the entire exposed surface of the intermediate layer 420 and the entire exposed surface of the substrate 410. The ALD layer 440 is formed continuously so that the entire layer is connected. Therefore, the entire surface of the member for a plasma processing apparatus 400 is composed of the ALD layer 440. As a result, in the member for a plasma processing apparatus 400, the intermediate layer 420 and the substrate 410 do not have exposed surfaces.

[0057] 6, an intermediate layer 520 is laminated on the entire surface of a substrate 510, and an ALD layer 540 is further laminated on the entire exposed surface of the intermediate layer 520. The ALD layer 540 is formed continuously so that the entire layer is connected. The entire surface of the member 500 for a plasma processing apparatus is composed of the ALD layer 540. As a result, in the member 500 for a plasma processing apparatus, the intermediate layer 520 and the substrate 510 do not have exposed surfaces.

[0058] In the members 400 and 500 for a plasma processing apparatus, the base material and the intermediate layer have no exposed surfaces. In this case, it is possible to suppress both the release of moisture from the base material and the absorption of moisture into the pores of the base material. When the base material is made of a ceramic sintered body, the base material is prone to absorbing moisture. Therefore, it is preferable to adopt a configuration in which neither the intermediate layer nor the base material has an exposed surface, as in the members 400 and 500 for a plasma processing apparatus.

[0059] In the plasma processing apparatus member according to the embodiment of the present invention, the material of the substrate is, for example, an aluminum alloy. Examples of materials other than the aluminum alloy include iron-based materials, nickel-based materials, titanium-based materials, cobalt-based materials, and invar materials (iron-36 nickel). The material of the substrate may also be a ceramic sintered body.

[0060] In the plasma processing apparatus member, the intermediate layer is preferably a thermal spray layer, a PVD layer, or a CVD layer. Furthermore, when the substrate is made of an aluminum alloy, the intermediate layer is also preferably an anodized layer (anodized aluminum layer). These intermediate layers are prone to moisture absorption and release due to the presence of pores within the coating, making them suitable for achieving the effects of the present invention. The intermediate layer may be a multilayer structure including one or more of a thermal spray layer, a PVD layer, a CVD layer, and an anodized aluminum layer.

[0061] The porosity of the pores present in the intermediate layer varies depending on how the intermediate layer is formed. If the intermediate layer is a thermal spray layer, the porosity is 0.5 to 5.0%. If the intermediate layer is a PVD layer, the porosity is 0.05 to 2.0%. If the intermediate layer is a CVD layer, the porosity is 0.02 to 1.0%. If the intermediate layer is an anodized layer, the porosity is 0.05 to 2.0%.

[0062] The porosity of the intermediate layer can be determined by cutting out the object, subjecting the cross section of the intermediate layer to cross-sectional milling, and then binarizing the SEM image obtained by SEM observation, and calculating the area ratio of the pore portion as the porosity.

[0063] In the member for a plasma processing apparatus, the thickness of the intermediate layer is preferably 1 μm or more and 500 μm or less. The thicker the intermediate layer, the more likely it is that cracks will occur due to the influence of internal stress. If cracks exist in the film, the film will be prone to moisture absorption and moisture release. On the other hand, in the member for a plasma processing apparatus, the entire exposed surface of the intermediate layer is covered with an ALD layer, so the intermediate layer can be made thicker without worrying about cracks. A thick intermediate layer can extend the service life of the member for a plasma processing apparatus.

[0064] When the intermediate layer is a thermal spray layer, the thickness of the intermediate layer is preferably 10 μm or more and 300 μm or less. When the intermediate layer is a PVD layer, the thickness of the intermediate layer is preferably 0.5 μm or more and 10 μm or less. When the intermediate layer is a CVD layer, the thickness of the intermediate layer is preferably 0.3 μm or more and 3 μm or less. When the intermediate layer is an anodized layer, the thickness of the intermediate layer is preferably 15 μm or more and 70 μm or less.

[0065] The material of the intermediate layer may be appropriately selected taking into consideration whether the intermediate layer is a conductive layer or an insulating layer, etc. When the intermediate layer is a conductive layer, examples of the material include a simple metal element selected from Mo, W, Ta, Cr, Ti, Al, Si, Ni, Nb, Fe, Cu, and Ag, an alloy containing one or more of these metal elements, a conductive compound containing one or more of these metal elements, or a mixture thereof.

[0066] When the intermediate layer is an insulating layer (dielectric layer), examples of the material thereof include oxide ceramics, fluoride ceramics, or oxyfluoride ceramics containing at least one element selected from the group consisting of rare earth elements, Mg, Al, Si, Ca, Ti, Ta, and Zr, or mixtures containing these.

[0067] Specific examples of the oxide ceramics include MgO, Al ２ O ３ , SiO ２ , CaO, TiO ２ , Y ２ O ３ , Ta ２ O ５ , Er ２ O ３ , Yb ２ O ３ , ZrO ２ , Y ３ Al ５ O １２ etc.

[0068] Specific examples of the fluoride ceramics include MgF ２ , AlF ３ , SiF ４ , CaF ２ , TiF ４ , Y.F.３ , TaF ５ , ErF ３ , YbF ３ , ZrF ４ etc.

[0069] Specific examples of the oxyfluoride ceramics include YOF, Y ５ O ４ F ７ , Y ６ O ５ F ８ , Y ７ O ６ F ９ , Y １７ O １４ F ２３ etc.

[0070] The mixture may be, for example, Y ２ O ３ and Al ２ O ３ A mixture of Y ２ O ３ and Y.F. ３ A mixture of Y ２ O ３ and YOF, YF ３ and YOF, YF ３ and Y ５ O ４ F ７ and mixtures thereof.

[0071] The plasma processing apparatus member includes an ALD layer. The ALD layer is a dense film with no pores present therein, and is moisture-impermeable. The ALD layer preferably has a thickness of 0.05 μm or more and 1.0 μm or less. If the ALD layer is too thin, its moisture-blocking effect will be poor. On the other hand, if the ALD layer is too thick, cracks will be more likely to occur in the ALD layer due to the influence of internal stress.

[0072] The material of the ALD layer may be an oxide ceramic, a fluoride ceramic, or an oxyfluoride ceramic containing at least one element selected from the group consisting of rare earth elements, Mg, Al, Si, Ca, Ti, Ta, and Zr, or a mixture thereof. Among these, it is preferable to use at least one of an oxide, a fluoride, and an oxyfluoride containing a rare earth element. An ALD layer made of these materials has excellent plasma resistance. Specific examples of the material of the ALD layer include Y. ２ O ３ , Y.F. ３ , YOF, YAG (Yttrium Aluminum Garnet), YAM (Yttrium Aluminum Monoclinic), Y—Al—F based compounds, Y—Al—O—F based compounds, etc.

[0073] The ALD layer may be a multilayer structure consisting of multiple layers made of different materials. In an embodiment of the present invention, the thickness of both the intermediate layer and the ALD layer can be determined from an image obtained by cutting out an object and observing the cross section with an electron microscope.

[0074] Next, a method for manufacturing a member for a plasma processing apparatus according to an embodiment of the present invention will be described. The method for manufacturing a member for a plasma processing apparatus includes the steps of: (A) forming an intermediate layer covering a part or all of a substrate, the intermediate layer including a film formed by a method other than the ALD method; (B) heat-treating the intermediate layer to remove moisture contained in the intermediate layer; and (C) forming an ALD layer covering the entire exposed surface of the intermediate layer.

[0075] In the above manufacturing method, in step (A), an intermediate layer is formed to cover part or all of the substrate. The intermediate layer is formed by a manufacturing method other than the ALD method. Specific examples of manufacturing methods other than the ALD method include a thermal spray method, a PVD method, a CVD method, and an anodization method. The intermediate layer formed by these methods has pores in the coating, so moisture adsorption and moisture release may occur.

[0076] In the above manufacturing method, after removing the moisture contained in the pores of the intermediate layer in step (B), the entire exposed surface of the intermediate layer is covered with the ALD layer, so that the intermediate layer can be shielded from the atmosphere while the pores of the intermediate layer contain almost no moisture. This prevents moisture from being reabsorbed into the pores of the intermediate layer, and the pores of the intermediate layer can be maintained in a state where they are almost free of moisture.

[0077] The amount of moisture contained in the pores of the intermediate layer affects the electrical properties (dielectric constant, dielectric loss tangent) of the intermediate layer. Because these electrical properties also affect the plasma output, when using a plasma processing apparatus, the RF output value for plasma generation must be adjusted to match the electrical properties. In other words, if the amount of moisture contained in the intermediate layer differs for each member for plasma processing apparatus (each plasma processing apparatus), the RF output value must be adjusted for each apparatus.

[0078] On the other hand, in the member for a plasma processing apparatus manufactured by the above manufacturing method, the pores of the intermediate layer do not contain moisture, and the amount of moisture contained in the intermediate layer does not vary. Therefore, the variation in the electrical properties of the intermediate layer due to the variation in the amount of moisture contained in the intermediate layer can be suppressed. As a result, in a plasma processing apparatus using the member for a plasma processing apparatus manufactured by the above manufacturing method, the frequency of adjusting the RF output value can be reduced.

[0079] As specific examples of the method for manufacturing the above-mentioned member for a plasma processing apparatus, for example, a first manufacturing method or a second manufacturing method described below can be adopted. Each manufacturing method will be explained below.

[0080] <First Manufacturing Method> Figure 7 is a process diagram of the first manufacturing method. This first manufacturing method is mainly used when forming a thermal spray layer as an intermediate layer. (1) First, a substrate is prepared, and its surface is degreased. This allows oil and other substances on the substrate surface to be removed. Note that if the substrate is made of a ceramic sintered body, this degreasing process may be omitted, or a cleaning process may be performed instead of the degreasing process. Next, if an intermediate layer is to be formed on part of the surface of the substrate, the area other than the area where the intermediate layer will be formed is masked.

[0081] (2) Next, the region of the substrate surface where the intermediate layer is to be formed is roughened by blasting. The conditions for the blasting may be selected appropriately according to the conditions for the thermal spraying in the next step. Depending on the surface condition of the substrate, the blasting may be omitted, or the surface may be roughened by a method other than blasting.

[0082] (3) Next, a thermal spray layer is formed as an intermediate layer. A known thermal spraying method may be used to form the thermal spray layer. Here, two thermal spray layers made of different materials may be formed as the intermediate layer. In this case, first, intermediate layer A (thermal spray layer A) may be formed, and then intermediate layer B (thermal spray layer B) may be formed on intermediate layer A. Furthermore, three or more layers may be stacked. Furthermore, intermediate layers (first intermediate layer, second intermediate layer, etc.) made of different materials may be formed in different regions of the surface of the substrate. In this case, the position of the mask may be changed each time an intermediate layer is formed.

[0083] After the thermal spray layer is formed, the thermal spray layer may be subjected to a smoothing treatment such as surface polishing, if necessary.

[0084] (4) The substrate on which the intermediate layer (sprayed layer) is formed is subjected to a heat treatment. This removes moisture from the substrate and intermediate layer. The heat treatment performed in this step is preferably a vacuum heat treatment. In this case, it is possible to prevent moisture from being reabsorbed into the pores of the substrate and intermediate layer from which moisture has been removed. Therefore, this step is preferably performed in a vacuum heating furnace.

[0085] Preferred heat treatment conditions in this step are a degree of vacuum of 100 Pa or less, a heating temperature of 80°C or more, and a heating time of 1 hour or more. A more preferred degree of vacuum is 10 Pa or less, and an even more preferred degree of vacuum is 1 Pa or less. A more preferred heating temperature is 100°C or more, and an even more preferred heating temperature is 120°C or more. A more preferred heating time is 2 hours or more, and an even more preferred heating time is 3 hours or more. Such heat treatment conditions are suitable for removing moisture contained in the substrate and intermediate layer. In the above heat treatment conditions, the degree of vacuum is, for example, 0.1 Pa or more, the heating temperature is, for example, 300°C or less, and the heating time is, for example, 24 hours or less.

[0086] (5) Next, an ALD layer is formed. The ALD layer is formed so as to cover at least the entire exposed surface of the intermediate layer. The ALD layer may be formed so as to cover the entire exposed surface of the intermediate layer and some or all of the exposed surface of the substrate.

[0087] The ALD layer can be formed by a known ALD method. In this step, the substrate on which the intermediate layer has been formed is placed in an ALD apparatus, and raw materials (precursors (e.g., organic metals), reactants (e.g., H ２ O)) are repeatedly supplied in a predetermined order, and the reaction between the precursor and the reactant is repeated until a predetermined thickness is reached, thereby forming an ALD layer. Here, the ALD layer may be formed by multilayering composed of layers of different materials. FIG. 8 is a cross-sectional SEM photograph of an example in which an ALD layer containing yttrium oxide is formed on a thermal spray coating containing yttrium oxide. As can be seen from FIG. 8, the ALD layer is continuously formed along the cracks in the thermal spray coating.

[0088] After completing step (4), it is preferable to perform step (5) promptly. Furthermore, if a vacuum heat treatment is performed in step (4), it is preferable to perform step (5) while maintaining the vacuum environment. This is to prevent moisture from being reabsorbed into the pores of the substrate and intermediate layer from which moisture was removed in step (4). Furthermore, if the vacuum environment is temporarily released after the vacuum heat treatment and then this step is performed, for example, if step (4) is performed in a vacuum heating furnace and then the substrate is moved to an ALD apparatus for this step, it is preferable to move the substrate with the intermediate layer formed thereon to the ALD apparatus while maintaining the temperatures of the substrate and intermediate layer at 100°C or higher. In this case, moisture is unlikely to be reabsorbed into the pores even if the substrate and intermediate layer are exposed to the atmosphere. By performing steps (1) to (5) as described above, a member for a plasma processing apparatus according to an embodiment of the present invention can be manufactured.

[0089] When an anodized layer is formed on the surface of the substrate as another intermediate layer, the substrate is anodized before the above steps (1) to (5) are performed, as shown in Fig. 9. In this case, an aluminum alloy is used as the material of the substrate.

[0090] <Second Manufacturing Method> Fig. 10 is a process diagram of the second manufacturing method. This second manufacturing method is mainly used when a PVD layer or a CVD layer is formed as the intermediate layer.

[0091] (1) First, a substrate is prepared and its surface is polished. Then, the substrate surface is cleaned. This makes it possible to make the surface of the substrate smooth and free of polishing powder, etc. Depending on the surface condition of the substrate, this polishing and cleaning may be omitted. Then, if an intermediate layer is to be formed on part of the surface of the substrate, the area other than the area where the intermediate layer is to be formed is masked.

[0092] (2) Next, a PVD layer or CVD layer is formed as an intermediate layer. These intermediate layers may be formed by a known PVD method or CVD method. Here, two intermediate layers made of different materials may be formed as the intermediate layer. In this case, intermediate layer A may be formed first, and then intermediate layer B may be formed on intermediate layer A. Furthermore, three or more layers may be stacked. Furthermore, intermediate layers made of different materials (first intermediate layer, second intermediate layer, etc.) may be formed in different regions of the surface of the substrate. In this case, the position of the mask may be changed each time an intermediate layer is formed.

[0093] When forming two intermediate layers, intermediate layer A and intermediate layer B may be intermediate layers formed by the same method or may be layers formed by different methods. A combination of two intermediate layers may be, for example, a combination in which intermediate layer A is a PVD layer and intermediate layer B is a CVD layer, or a combination in which intermediate layer A is a CVD layer and intermediate layer B is a PVD layer. The intermediate layer may be composed of three or more layers. Furthermore, intermediate layers (such as a first intermediate layer and a second intermediate layer) made of different materials and formed by the same or different methods may be formed in different regions of the surface of the substrate. In this case, the position of the mask may be changed each time an intermediate layer is formed.

[0094] After the intermediate layer is formed, it may be subjected to a smoothing treatment such as surface polishing, if necessary.

[0095] (3) The substrate on which the intermediate layer (PVD layer or CVD layer) is formed is subjected to a heat treatment. This removes moisture contained in the substrate and the intermediate layer. This step may be performed in the same manner as step (4) in the first manufacturing method described above.

[0096] (4) Next, an ALD layer is formed. The ALD layer is formed so as to cover at least the entire exposed surface of the intermediate layer. The ALD layer may be formed so as to cover the entire exposed surface of the intermediate layer and part or all of the exposed surface of the base material. This step may be performed in the same manner as step (5) in the first manufacturing method already described. By performing these steps (1) to (4), a member for a plasma processing apparatus according to an embodiment of the present invention can also be manufactured.

[0097] When an anodized layer is formed on the surface of the substrate as another intermediate layer, the substrate is anodized before the above steps (1) to (4) are performed, as shown in Fig. 11. In this case, an aluminum alloy is used as the material of the substrate.

[0098] The manufacturing method of the plasma processing apparatus member according to the embodiment of the present invention is not limited to the first manufacturing method or the second manufacturing method. The manufacturing method of the plasma processing apparatus member may be configured by combining a part of the first manufacturing method and a part of the second manufacturing method. Specifically, for example, the intermediate layer may be formed by forming only an anodized layer. Alternatively, the intermediate layer may be formed by forming at least one of a PVD layer, a CVD layer, and an anodized layer on a part of the surface of the substrate, and then forming a thermal spray layer on a part or all of the remaining surface of the substrate. Alternatively, the intermediate layer may be formed by forming a thermal spray layer on a part or all of the surface of the substrate, and then laminating a PVD layer or a CVD layer on the thermal spray layer. Furthermore, the intermediate layer may be formed by forming a PVD layer, a CVD layer, or an anodized layer on a part or all of the surface of the substrate, and then laminating a thermal spray layer on top of that.

[0099] Other Embodiments The plasma processing apparatus components according to the embodiments of the present invention can be used in plasma processing apparatuses other than plasma etching apparatuses. Specific examples of other plasma processing apparatuses include various film formation apparatuses such as CVD apparatuses.

[0100] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims.

[0101] REFERENCE SIGNS LIST 10 Plasma etching apparatus 11 Outermost ring 13 Loading / unloading port 17 Processing space 20 Electrostatic chuck 21 Base 23 Insulating layer 24 Dielectric layer 25 Adsorption electrode 26 DC power supply 27 Switch 30 Power supply terminal part 31 Power supply member 33 Insulating member 40 Upper electrode 42 Electrode plate 44 Electrode support 46 Gas flow path 46a Gas diffusion chamber 46b Gas flow hole 46c Gas discharge hole 48 Gas supply pipe 51 First high frequency power supply 52 Second high frequency power supply 53, 54 Matching box 60 Electrostatic chuck outer ring 70 Exhaust ring 110A, 110B, 110C, 110D, 110E Base material 120A, 120B, 120C, 120D, 120E First intermediate layer 130A, 130B, 130C, 130D, 130E Second intermediate layer 140A, 140B, 140C, 140D, 140E ALD layer 200, 300, 400, 500 Member for plasma processing apparatus 210, 310, 410, 510 Base material 220, 420, 520 Intermediate layer 320 Intermediate layer A 330 Intermediate layer B

Claims

1. A member for a plasma processing apparatus comprising: a substrate; an intermediate layer other than an ALD layer covering part or all of the substrate; and an ALD (Atomic Layer Deposition) layer continuously covering the surface of the intermediate layer, wherein the intermediate layer has no exposed surface.

2. The member for a plasma processing apparatus according to claim 1, wherein the film thickness of the ALD layer is 0.05 μm or more and 1.0 μm or less.

3. The member for a plasma processing apparatus according to claim 1, wherein the thickness of the intermediate layer is 1 μm or more and 500 μm or less.

4. The member for a plasma processing apparatus according to claim 1, wherein the ALD layer contains at least one of an oxide, a fluoride, and an oxyfluoride containing at least one element selected from the group consisting of rare earth metals, Mg, Al, Si, Ca, Ti, Ta, and Zr.

5. The member for a plasma processing apparatus according to claim 1, wherein the intermediate layer is a thermal spray layer, a PVD layer, a CVD layer, an anodized layer, or a multilayer including at least one of these.

6. The member for a plasma processing apparatus according to claim 1, wherein the ALD layer continuously covers the surface of the substrate, and the substrate has no exposed surface.

7. A method for manufacturing a member for a plasma processing apparatus, comprising: (A) a step of forming an intermediate layer covering part or all of a substrate, the intermediate layer including a film formed using a manufacturing method other than the ALD method; (B) a step of heat-treating the intermediate layer to remove moisture contained in the intermediate layer; and (C) a step of forming an ALD layer covering the entire exposed surface of the intermediate layer.

8. The method for manufacturing a member for a plasma processing apparatus according to claim 7, wherein the heat treatment is a vacuum heat treatment.

9. The method for manufacturing a member for a plasma processing apparatus according to claim 8, wherein the heat treatment is carried out under conditions of 100 Pa or less, 80° C. or more, and for 1 hour or more.

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