Structure member

Abstract

To provide a structure member capable of preventing detachment of a protective film.SOLUTION: A structure member 10 comprises a base material 100, and a protective film 200 covering a surface 110 of the base material 100. The protective film 200 has a surface layer part 201 which is a portion including a surface 210 opposite to the base material 100, and a deep layer part 202 which is a portion nearer the base material 100 than the surface layer part 201. Porosity of the surface layer part 201 is larger than that of the deep layer part 202.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to structural members. [Background technology]

[0002] Structural members having a protective film on the surface of a substrate are used in various fields such as semiconductor manufacturing equipment. For example, as described in the following Patent Document 1, in a semiconductor manufacturing equipment, a protective film is formed on the surface of a substrate constituting an inner wall of a chamber to protect the substrate from plasma. For example, oxide ceramics such as yttria, fluoride ceramics such as yttrium fluoride, etc. are used as such a protective film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-321183 A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, in the case of an etching device, the protective film is exposed to fluorine-based plasma during substrate processing. At this time, the surface portion of the protective film expands slightly due to fluorination. Also, during the dry cleaning process of the device, the protective film is exposed to oxygen-based plasma. At this time, the surface portion of the protective film contracts slightly due to oxidation. In this way, the surface portion of the protective film repeatedly expands and contracts, so that many tiny cracks (microcracks) are likely to occur over time. As time passes, each crack may extend deep into the protective film, causing parts of the protective film to fall off.

[0005] The present invention has been made in view of the above problems, and an object of the present invention is to provide a structural member capable of preventing the protective film from falling off. [Means for solving the problem]

[0006] In order to solve the above problems, the structural member according to the present invention includes a substrate and a protective film covering a surface of the substrate. The protective film has a surface layer portion that is a portion including the surface opposite to the substrate, and a deep layer portion that is a portion closer to the substrate than the surface layer portion, and the porosity of the surface layer portion is greater than the porosity of the deep layer portion.

[0007] In such a structural member, the porosity of the surface layer is relatively large, so the entire surface of the protective film is not a single continuous surface, but is divided into many surfaces by small voids. In such a configuration, even if the surface of the protective film repeatedly expands and contracts, and small cracks occur, the gaps prevent the cracks from expanding. This makes it possible to prevent the cracks from growing too large and causing the protective film to fall off. Effect of the Invention

[0008] According to the present invention, it is possible to provide a structural member capable of preventing the protective film from falling off. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic cross-sectional view of a structural member according to the present embodiment. [Diagram 2] FIG. 13 is a diagram showing the relationship between each position in the depth direction of a protective film and the porosity. [Diagram 3] FIG. 13 is a diagram showing the relationship between each position in the depth direction of a protective film and the porosity. [Figure 4] 4A to 4C are diagrams for explaining a method for manufacturing a structural member according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicated description will be omitted.

[0011] The structural member 10 according to this embodiment is used as a member constituting the inner wall of a processing chamber in a semiconductor manufacturing apparatus (not shown) such as a plasma etching apparatus. Note that the use of such a structural member 10 is merely an example, and is not limited to use in semiconductor manufacturing apparatus.

[0012] 1, the structural member 10 includes a substrate 100 and a protective film 200. In a plasma etching device or the like, a surface 210 of the protective film 200 is exposed to the space inside a chamber. The protective film 200 is provided for the purpose of protecting a surface 110 of the substrate 100 from plasma.

[0013] The substrate 100 is a member that occupies almost the entirety of the structural member 10. In this embodiment, the substrate 100 is a ceramic sintered body containing high-purity aluminum oxide (Al2O3), but it may be a different type of ceramic, or may be a member other than ceramic (for example, a metal member). In this embodiment, the surface 110 of the substrate 100 is a flat surface, but the surface 110 may have irregularities, inclinations, or the like.

[0014] As described above, the protective film 200 is a film formed to protect the substrate 100 from plasma. The protective film 200 is formed so as to cover the entire surface 110 of the substrate 100. In this embodiment, the protective film 200 is configured as a film containing polycrystalline yttria (Y2O3), but may be a ceramic film made of a different material. The thickness of the protective film 200 is appropriately set according to the length of time for which durability is required to be maintained, etc. In this embodiment, the thickness of the protective film 200 is 10 μm.

[0015] The protective film 200 of this embodiment is formed by using an aerosol deposition method on the surface 110 of the base material 100 after baking. As is well known, in the aerosol deposition method, microparticles, which are the material of the protective film 200, are dispersed in a gas to form an "aerosol," which is then sprayed from a nozzle toward the surface 110 and collided with it. On the surface 110, the microparticles are deformed and crushed by the impact of the collision, so that the microparticles bond to each other and gradually accumulate as the protective film 200.

[0016] 1, the portion surrounded by dotted line DL1 is a portion of protective film 200 that includes surface 210 on the outer side (i.e., the side opposite to substrate 100). This portion is also referred to below as "surface layer portion 201." In the same figure, the portion surrounded by dotted line DL2 is a portion of protective film 200 that is closer to substrate 100 than surface layer portion 201. This portion is also referred to below as "deep layer portion 202."

[0017] 1 shows only a part of the surface layer 201, not the whole. The surface layer 201 refers to the whole of the portion of the protective film 200 that is at the same height as the dotted line DL1 in FIG. 1. Similarly, the dotted line DL2 in FIG. 2 shows only a part of the deep layer 202, not the whole. The deep layer 202 refers to the whole of the portion of the protective film 200 that is at the same height as the dotted line DL2 in FIG. 1. The deep layer 202 may be any portion of the protective film 200 that is closer to the substrate 100 than the surface layer 201, and may be a portion at a different height from the dotted line DL2 in FIG. 1.

[0018] The protective film 200 of this embodiment is formed entirely from the same material, including the surface layer 201 and the deep layer 202. However, the porosity of each part is not uniform throughout, but is different between the surface layer 201 and the deep layer 202. Specifically, the porosity of the surface layer 201 is lower than the porosity of the deep layer 202. The "porosity" here refers to the proportion of the area of ​​voids to a unit area in a cross section of the protective film 200 perpendicular to the surface 210.

[0019] 2 shows an example of the relationship between the depth position (horizontal axis) of protective film 200 and the porosity (vertical axis) of protective film 200. The "depth position" refers to a position (coordinate) along a direction perpendicular to surface 210. The depth position on surface 210 is set to "0", and the depth position of protective film 200 at the boundary with substrate 100 is set to "d2". "d1" in FIG. 2 is the depth position of the end of surface layer 201 on the substrate 100 side.

[0020] 2, the porosity at each depth position of the protective film 200 is sufficiently small in the portion on the substrate 100 side (the right side in FIG. 2) and is a constant value that changes little with depth position. On the other hand, in the surface layer portion 201 of the protective film 200, the durability gradually increases toward the surface 210 side (the left side in FIG. 2), and is the largest at the surface 210.

[0021] The above-described distribution of porosity in the protective film 200 is merely an example. The relationship between the depth position and the porosity in the protective film 200 may be as shown in the example of FIG. 3. In the example of FIG. 3, the porosity of the protective film 200 changes stepwise depending on the depth position. In this example as well, the porosity of the protective film 200 is greatest at the surface 210.

[0022] As described above, the surface layer 201 has a larger porosity than the deep layer 202. When comparing the porosity between the surface layer 201 and the deep layer 202, for example, the average porosity value in each portion of the surface layer 201 and the average porosity value in each portion of the deep layer 202 may be calculated, and the two values ​​may be compared.

[0023] The advantages of the above-mentioned configuration will be described. For example, when the structural member 10 is used for the inner wall of the chamber of an etching device, the protective film 200 is exposed to fluorine-based plasma during the processing of the substrate. At this time, the surface 210 of the protective film 200 expands slightly due to fluorination. Also, during the dry cleaning process of the device, the protective film 200 is exposed to oxygen-based plasma. At this time, the surface 210 of the protective film 200 shrinks slightly due to oxidation. In this way, the surface 210 of the protective film 200 expands and shrinks repeatedly, so that many minute cracks (microcracks) are likely to occur over time. As time passes, each crack extends to the back of the protective film 200, and there is a possibility that a part of the protective film 200 will fall off.

[0024] Therefore, in this embodiment, as described above, the porosity of the surface layer 201 of the protective film 200 is made larger than the porosity of the deep layer 202, which is the innermost part of the surface layer 201. In the structural member 10 having such a configuration, the entire surface 210 of the protective film 200 is not a continuous single surface, but is divided into many surfaces through minute gaps. In such a configuration, even if the surface 210 of the protective film 200 expands and contracts repeatedly and a minute crack occurs, the extension of the crack is prevented by the gap. Therefore, it is possible to prevent a situation in which the crack grows large and causes the protective film 210 to fall off.

[0025] It is also conceivable that a small amount of particles may be generated due to minute cracks, but if the porosity of the surface layer 201 is increased as in this embodiment, the generated particles will be captured in the voids, which has the advantage of reducing the amount of particles that fall from the structural member 10.

[0026] Furthermore, if the porosity of the surface layer 201 is large, the entire surface 210 will be in a sparse state. This has the advantage that dirt, particles, and the like attached to the surface can be easily removed together with part of the protective film 200.

[0027] Furthermore, if the porosity of the surface layer 201 is large, stress caused by thermal expansion and the like is less likely to concentrate on a part (e.g., a scratch) of the protective film 200. This makes it possible to prevent damage to the protective film 200 caused by stress, generation of large particles, and the like.

[0028] A method for manufacturing the structural member 10 will be described with reference to Fig. 4. As shown in Fig. 4(A), first, a substrate 100 is prepared. It is preferable that the surface roughness, etc. of a surface 110 of the substrate 100 is adjusted in advance to such an extent that a protective film 200 can be stably formed.

[0029] 4(B), a protective film 200 is formed so as to cover the surface 110 of the substrate 100. The protective film 200 of this embodiment is formed by using the aerosol deposition method as described above.

[0030] In order to make the porosity of the protective film 200 different depending on the depth position, the film formation conditions are not always the same during the formation of the protective film 200, but are changed during the film formation. For example, the injection concentration of the microparticles, which are the material of the protective film 200, may be increased after the timing when the formation of the deep layer portion 202 is completed and the formation of the surface layer portion 201 begins. In addition, after the above timing, the pressure around the injection nozzle (pressure in the film formation chamber) may be increased, or the incidence angle of the microparticles with respect to the film formation surface may be increased. In addition, the type of microparticles may be changed after the above timing. For example, after the microparticles obtained from granulated powder with low moisture content are injected in the first half, the microparticles obtained from granulated powder with high moisture content may be injected in the second half.

[0031] Even when the protective film 200 is formed by a method other than the aerosol deposition method, the porosity can be adjusted according to the depth position by changing the film formation conditions midway, in the same manner as described above.

[0032] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Any design modifications made by a person skilled in the art to these specific examples are also included within the scope of the present disclosure as long as they have the features of the present disclosure. The elements of each of the above-mentioned specific examples and their arrangements, conditions, shapes, etc. are not limited to those exemplified and can be changed as appropriate. The combination of each of the elements of each of the above-mentioned specific examples can be changed as appropriate as long as no technical contradiction occurs. [Explanation of symbols]

[0033] 10: Structural members 100: Base material 110: Surface 200: Protective film 201: Surface layer 202:Deep 210: Surface

Claims

1. A substrate; A protective film covering the surface of the base material; The protective film is A surface layer portion including a surface opposite to the substrate; A deep layer portion which is a portion closer to the substrate than the surface layer portion, A structural member, characterized in that the porosity of the surface layer is greater than the porosity of the deep layer.

2. 2. The structural member according to claim 1, wherein the protective film is a film formed by an aerosol deposition method.

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