Structural member

Abstract

To provide a structural member that can prevent the surface of a protective film from being polished more than necessary during manufacturing.SOLUTION: A structural member 10 includes a base material 100 and a protective film 200 that covers a surface 110 of the base material 100. Particles 300 with a higher hardness than the protective film 200 are dispersed and arranged inside the protective film 200.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a structural member. [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 Patent Document 1 below, 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. [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] The protective film is formed on the surface of the substrate by using a film forming method such as an aerosol deposition method. The surface of the protective film is then polished to adjust its flatness. At this time, stress caused by polishing may remain in the surface layer of the protective film. Such residual stress may cause the durability of the protective film to decrease or cause particles to be generated. Therefore, after the surface of the protective film is polished, it is preferable to perform soft polishing on the surface layer of the surface to release the residual stress. The "soft polishing" here means polishing the surface of the protective film without causing residual stress as much as possible, for example, by using a soft member such as an abrasive cloth or by performing chemical etching.

[0005] The thickness of the surface layer to be removed by soft polishing is very thin, at most about 100 nm. If any more thickness is removed, the durability of the protective film will be unnecessarily reduced, which is not desirable. For this reason, when performing soft polishing, it is necessary to perform the polishing while checking each time how much thickness has been removed from the surface of the protective film.

[0006] A possible method for checking the thickness that has been removed is to use, for example, a reflection spectroscopic membrane pressure gauge to measure the overall thickness of the protective film each time and calculate the amount of change. However, it is difficult to accurately measure minute changes of about 100 nm or less using a reflection spectroscopic membrane pressure gauge. For this reason, when performing soft polishing, it is necessary to remove the surface layer of the protective film in excess of the minimum thickness that needs to be removed.

[0007] The present invention has been made in consideration of such problems, and its object is to provide a structural member that can prevent the surface of a protective film from being polished more than necessary during manufacturing. [Means for solving the problem]

[0008] In order to achieve the above object, a structural member according to the present invention includes a base material and a protective film covering a surface of the base material. The protective film contains high-hardness particles dispersed therein, the high-hardness particles having a harder property than the protective film.

[0009] When soft polishing is performed on a protective film having such a structure, the hard particles exposed on the surface of the protective film are hardly removed and remain, so that the hard particles protrude from the surface of the protective film. In this case, the amount of the protective film removed is approximately equal to the amount of the hard particles protruding.

[0010] The amount of protrusion of the hard particles can be measured relatively easily and with high accuracy using a measuring device such as an electric micrometer. Therefore, by performing soft polishing while measuring the amount of protrusion, i.e., the amount of removal, each time, it is possible to remove only the necessary amount of the surface layer. In other words, it is possible to prevent the surface of the protective film from being polished more than necessary.

[0011] After the structural member is mounted on an etching device or the like and the surface of the protective film is exposed to plasma for a certain period of time and deteriorated, the surface can be re-polished to remove the deteriorated portion in order to reuse the structural member. In other words, the surface of the deteriorated protective film can be refreshed. In the structural member having the above configuration, the high-hardness particles are dispersed not only on the surface of the protective film but also throughout the inside. Therefore, when refreshing, the protective film can be removed again by an appropriate thickness by performing soft polishing while measuring the protrusion amount of the high-hardness particles, as described above. Effect of the Invention

[0012] According to the present invention, it is possible to provide a structural member capable of preventing the surface of a protective film from being polished more than necessary during production. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a schematic cross-sectional view of a structural member according to the present embodiment. [Diagram 2] 3 is a diagram illustrating a cross section of a protective film in the structural member according to the present embodiment. FIG. [Diagram 3] 4A to 4C are diagrams for explaining a method for manufacturing a structural member according to the present embodiment. [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

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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) as a main component, but may be a ceramic film made of a material other than this. The thickness of the protective film 200 is appropriately set depending on 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.

[0019] 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 or crushed by the impact of the collision, so that the microparticles bond to each other and gradually accumulate as the protective film 200. The protective film 200 may be a film formed by using another film formation method.

[0020] 2 illustrates a cross section of the protective film 200 in more detail. As shown in the figure, a plurality of particles 300 are dispersed inside the protective film 200. In this embodiment, the particles 300 are formed of a material mainly composed of alumina. Therefore, the hardness of the particles 300 (alumina) is higher than the hardness of the protective film 200 (yttria) surrounding the particles 300. Each particle 300 corresponds to a "high hardness particle" in this embodiment.

[0021] The particles 300 may be made of other materials as long as their hardness is higher than that of the protective film 200. When the main component of the protective film 200 is yttria as in this embodiment, the particles 300 may be made of, for example, a material containing yttrium, aluminum, and garnet (YAG). By using such a composite material, it is also possible to increase the mechanical strength of the entire protective film 200 including the particles 300.

[0022] The arrangement density of the particles 300, i.e., the number of the particles 300 contained per unit volume of the protective film 200, is approximately uniform throughout the entire protective film 200. Most of the particles 300 are entirely embedded inside the protective film 200, but some of the particles 300 protrude outward from the surface 210 of the protective film 200.

[0023] The distance from the surface 210 of the protective film 200 to the tip of the protruding particle 300 (the distance along the direction perpendicular to the surface 210) is defined below as the "protrusion amount H" of the particle 300. In this embodiment, the protrusion amount H of each particle 300 protruding from the surface 210 is uniform. A method for making each protrusion amount H uniform will be described later. It is sufficient that the protrusion amounts H are roughly uniform, and may vary within a range of, for example, about 10% of the average value.

[0024] As shown in FIG. 2, the tip 310 of each particle 300 protruding from the surface 210 of the protective film 200 forms a flat surface parallel to the surface 210 .

[0025] A method for manufacturing the structural member 10 will be described with reference to Fig. 3 and Fig. 4. As shown in Fig. 3(A), a substrate 100 is first prepared. It is preferable that the surface roughness, etc. of the surface 110 of the substrate 100 is adjusted in advance to such an extent that the protective film 200 can be stably formed.

[0026] 3(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.

[0027] In this embodiment, the particles 300 are mixed in advance with the microparticles that are the material of the protective film 200 at a predetermined ratio, and are mixed sufficiently so that the distribution is uniform. The mixture of particles obtained in this manner is dispersed in gas to form an "aerosol," which is then sprayed from a nozzle toward the surface 110 and collided. Therefore, when the film formation by the aerosol deposition method is completed, the particles 300 are dispersed and arranged inside the protective film 200, as shown in FIG. 4(A). At this point, there are almost no particles 300 protruding from the surface 210A of the protective film 200. The surface 210A is a flat surface overall, and all the particles 300 are embedded in the back side.

[0028] Next, the entire surface 210A in FIG. 4(A) is polished to adjust its flatness. FIG. 4(B) shows the state after polishing. The new surface that appears after polishing the surface 210A in FIG. 4(A) is also referred to as "surface 210B" below. The amount of protective film 200 removed until surface 210A becomes surface 210B is about 1.0 μm to 2.5 μm. A grindstone made of diamond is used for polishing at this time. Therefore, the particles 300 near the surface of protective film 200 are polished together with protective film 200, and the upper end in the figure becomes a flat surface. The flat surface is the part that becomes tip 310 in FIG. 2. At the time of FIG. 4(B), tip 310 is on the same plane as surface 210A.

[0029] The above polishing performed to obtain the state shown in FIG. 4(B) is also referred to as "hard polishing" below to distinguish it from the soft polishing described below. The amount of protective film 200 removed in hard polishing is relatively large, about 1.0 μm to 2.5 μm, as described above, and can be measured by a reflection spectroscopic film thickness meter. Hard polishing is performed while measuring the amount of removal each time, and the hard polishing can be terminated when the amount of removal reaches a preset target value. The grindstone used in hard polishing may be diamond as described above, but may also be, for example, SiC or CBN (Cubic Boron Nitride).

[0030] In hard polishing, the protective film 200 is scraped off to a relatively large extent, so that residual stress exists in the surface 210B after polishing. Such residual stress may cause the durability of the protective film 200 to decrease or cause particles to be generated. Therefore, in order to release the residual stress in the surface 210B, soft polishing is performed following the hard polishing. "Soft polishing" refers to polishing the surface 210B of the protective film 200 without generating residual stress as much as possible, for example, by using a soft member such as an abrasive cloth or by performing chemical etching.

[0031] The thickness of the surface layer to be removed by soft polishing is very thin, about 100 nm at most. If a thickness greater than this is removed, the durability of the protective film 200 will be unnecessarily reduced, which is undesirable. For this reason, when performing soft polishing, it is necessary to perform polishing while checking each time how much of the protective film 200 has been removed from the surface 210B.

[0032] A method for checking the removed thickness is, for example, to measure the total thickness of the protective film 200 each time using a reflection spectroscopic membrane pressure gauge and calculate the amount of change. However, it is difficult to accurately measure minute changes of about 100 nm or less using a reflection spectroscopic membrane pressure gauge. For this reason, when performing soft polishing in the conventional configuration, it was necessary to remove an excess of the surface layer of the protective film 200 beyond the minimum thickness required to be removed.

[0033] Therefore, in this embodiment, the particles 300 are dispersed inside the protective film 200 as described above, which makes it easy to measure the amount of removal. FIG. 4(C) shows a schematic diagram of the state of the protective film 200 during soft polishing. When soft polishing is performed, the protective film 200 is gradually removed from the surface. Therefore, the surface 210B in FIG. 4(B) gradually recedes toward the substrate 100 side (the lower side in FIG. 4). The surface gradually receding from the state in FIG. 4(B) in this way is also referred to as "surface 210C" below.

[0034] On the other hand, since the particles 300 have a higher hardness than the protective film 200, they are hardly removed even by soft polishing, and remain in their original shape. Therefore, as shown in Fig. 4(C), all of the particles 300 that had flat tips 310 protrude outward from the surface 210C. The amount of protrusion H0 of the particles 300 from the surface 210C is approximately equal to the thickness of the protective film 200 that has been removed up to that point (the above-mentioned removal amount).

[0035] The protrusion amount H0 of the particle 300 can be measured relatively easily and with high accuracy by using a measuring device such as an electric micrometer. Therefore, if soft polishing is performed while measuring the protrusion amount H0, i.e., the amount of removal of the protective film 200, each time, it is possible to remove only the necessary amount of the surface layer. In other words, it is possible to prevent the surface 210 of the protective film 200 from being polished more than necessary. When the protrusion amount H0 of the particle 300 becomes equal to the target value of the removal amount set in advance, the soft polishing can be ended. The surface 210C at this time is the surface 210 in FIG. 2. The protrusion amount H0 at this time is the protrusion amount H in FIG. 2.

[0036] During the soft polishing, the tip 310 of each particle 300 protruding from the surface 210C of the protective film 200 becomes a flat surface parallel to the surface 210C. Therefore, the protrusion amount H0 can be easily and accurately measured using an electric micrometer or the like.

[0037] The protrusion amount H0 of the particle 300 may be directly measured using an electric micrometer or the like, or may be estimated or calculated by other methods. For example, the surface 210C may be photographed from above during the soft polishing, and the protrusion amount H0 of the particle 300 may be estimated or calculated based on the size of each particle 300 in the obtained image.

[0038] The soft polishing is performed uniformly over the entire surface 210B in FIG. 4B. Therefore, the protrusion amount H0 of the particles 300, i.e., the amount of removal of the protective film 200, is generally uniform over the entire surface. In order to make the amount of removal of the protective film 200 more uniform, the protrusion amount H0, i.e., the amount of removal of the protective film 200, may be measured individually at multiple points on the surface 210C, and partial soft polishing may be performed as necessary.

[0039] In soft polishing, the particles 300 are hardly removed as shown in FIG. 4C, so the measured protrusion amount H0 of the particles 300 can be used as the removal amount of the protective film 200. However, depending on the material of the particles 300, there may be cases where the change in the shape of the particles 300 due to soft polishing cannot be ignored. Even in such cases, there is a certain correlation between the measured protrusion amount H0 of the particles 300 and the removal amount of the protective film 200. Therefore, if the correlation is grasped in advance by an experiment or the like, the removal amount can be easily and accurately calculated based on the protrusion amount H0.

[0040] After the structural member 10 is attached to an etching device or the like and the surface 210 of the protective film 200 is exposed to plasma for a certain period of time and deteriorated, the deteriorated portion may be removed by re-polishing the surface 210 in order to reuse the structural member 10. In other words, the surface 210 may be refreshed.

[0041] The particles 300 are dispersed not only on the surface 210 of the protective film 200 but also throughout the interior. Therefore, during refreshing, similarly to the above, by performing soft polishing while measuring the protrusion amount H0 of the particles 300, it is possible to remove an appropriate thickness of the protective film 200 again.

[0042] 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]

[0043] 10: Structural members 100: Base material 110: Surface 200: Protective film 300: Particle

Claims

1. A substrate; A protective film covering the surface of the base material; A structural member, comprising: high-hardness particles having a harder property than the protective film dispersed inside the protective film.

2. 2. The structural member according to claim 1, wherein a plurality of said high-hardness particles protrude from a surface of said protective film.

3. 3. The structural member according to claim 2, wherein the amount of protrusion of each of said high-hardness particles from the surface of said protective film is uniform.

4. 4. A structural member according to claim 3, wherein a tip of each of said high-hardness particles protruding from the surface of said protective film forms a flat surface parallel to the surface of said protective film.

5. The structural member of claim 1 , wherein the protective coating comprises yttria and the high hardness particles comprise alumina.

6. 2. The structural member of claim 1, wherein the protective coating comprises yttria and the high hardness particles comprise yttrium, aluminum, and garnet.

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