structural members

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 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 Patent Document 1 below, in semiconductor manufacturing equipment, a protective film is formed on the surface of a substrate that constitutes the inner wall of a chamber to protect the substrate from plasma. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-321183 Summary of the Invention [Problem to be solved by the invention]

[0004] The protective film is formed on the surface of the substrate using a film formation method such as aerosol deposition. The surface of the protective film is then polished to adjust its flatness. At this time, stress caused by the polishing may remain in the surface layer of the protective film. Such residual stress may cause a decrease in the durability of the protective film or the generation of particles. Therefore, after the surface of the protective film is polished, it is preferable to perform soft polishing on the surface layer to release the residual stress. Here, "soft polishing" refers to polishing the surface of the protective film while minimizing the generation of residual stress, for example, by using a soft member such as an abrasive cloth or by performing chemical etching.

[0005] The thickness of the surface layer that should be removed by soft polishing is very thin, at most about 100 nm. Removing a thickness greater than this is not desirable because it unnecessarily reduces the durability of the protective film. For this reason, when performing soft polishing, it is necessary to check each time how much of the protective film has been removed from the surface.

[0006] One possible method for checking the thickness removed is to measure the overall thickness of the protective film using, for example, a spectroscopic diaphragm meter and calculate the amount of change. However, it is difficult to accurately measure minute changes of about 100 nm or less using a spectroscopic diaphragm meter. For this reason, when performing soft polishing, it is necessary to remove excess surface layer of the protective film beyond the minimum thickness required to be removed.

[0007] The present invention has been made in view 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 solve the above problems, a structural member according to the present invention includes a substrate and a protective film covering the surface of the substrate, wherein high-hardness particles having a hardness higher than that of the protective film are dispersed within the protective film.

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

[0010] The protrusion amount of the high-hardness 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 protrusion amount, i.e., the removal amount, 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 a structural member is mounted in 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 configured as described above, the high-hardness particles are dispersed not only on the surface of the protective film but also throughout the interior. Therefore, when refreshing, similarly to the above, by performing soft polishing while measuring the protrusion amount of the high-hardness particles, it is possible to remove the protective film to an appropriate thickness again. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a structural member that can prevent the surface of the protective film from being polished more than necessary during manufacturing. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a diagram schematically illustrating a cross section of a structural member according to the present embodiment. [Figure 2] FIG. 2 is a diagram illustrating a cross section of a protective film in the structural member according to the present embodiment. [Figure 3] 1A to 1C are diagrams for explaining a method for manufacturing a structural member according to the present embodiment. [Figure 4] 1A to 1C are diagrams for explaining a method for manufacturing a structural member according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0015] The structural member 10 according to this embodiment is used as a member that constitutes 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 apparatuses.

[0016] 1, a structural member 10 includes a substrate 100 and a protective film 200. In a plasma etching apparatus or the like, a surface 210 of the protective film 200 is exposed to the space within a chamber. The protective film 200 is provided to protect a surface 110 of the substrate 100 from plasma.

[0017] The substrate 100 is a member that occupies substantially the entire 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). Furthermore, although the surface 110 of the substrate 100 is flat in this embodiment, the surface 110 may have irregularities, a slope, 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 it may also be a ceramic film made of a different material. The thickness of the protective film 200 is set appropriately 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 for 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 caused to collide. On the surface 110, the impact of the collision causes deformation and fragmentation of the microparticles, so that the microparticles bond together and gradually deposit as the protective film 200. The protective film 200 may be a film formed using another film formation method.

[0020] FIG. 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 from a material containing alumina as a main component. Therefore, the hardness of the particles 300 (alumina) is higher than the hardness of the surrounding protective film 200 (yttria). 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 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 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 hereinafter defined 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 the protrusion amounts H uniform will be described later. The protrusion amounts H need only be roughly uniform, and may vary, for example, within a range of 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 Figures 3 and 4. As shown in Figure 3(A), first, a substrate 100 is prepared. It is preferable that the surface roughness and the like of the surface 110 of the substrate 100 be adjusted in advance to an extent that the protective film 200 can be stably formed.

[0026] 3(B), a protective film 200 is formed 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, particles 300 are mixed in advance with the microparticles that are the material of the protective film 200 at a predetermined ratio, and the particles are thoroughly mixed to ensure uniform distribution. The particle mixture thus obtained is dispersed in a gas to form an "aerosol," which is then sprayed from a nozzle toward the surface 110 and collided with it. Therefore, upon completion of film formation using the aerosol deposition method, the particles 300 are dispersed and arranged inside the protective film 200, as shown in FIG. 4(A). At this point, almost no particles 300 protrude from the surface 210A of the protective film 200. The surface 210A is entirely flat, and all of the particles 300 are embedded deep within it.

[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 from surface 210A to surface 210B is approximately 1.0 μm to 2.5 μm. A diamond grinding wheel is used for this polishing. As a result, the particles 300 near the surface of the protective film 200 are polished together with the protective film 200, and the upper end in the figure becomes a flat surface. This flat surface is the portion that becomes the tip 310 in FIG. 2. At the point in FIG. 4(B), the tip 310 is on the same plane as the surface 210A.

[0029] The polishing performed to achieve the state shown in FIG. 4(B) will be 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 using a reflectance 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 grinding stone used in hard polishing may be diamond, as described above, but may also be SiC or CBN (Cubic Boron Nitride), for example.

[0030] In hard polishing, a relatively large amount of the protective film 200 is removed, leaving residual stress on the surface 210B after polishing. Such residual stress can reduce the durability of the protective film 200 and cause particles to be generated. Therefore, in order to release the residual stress on the surface 210B, soft polishing is performed following the hard polishing. "Soft polishing" refers to polishing the surface 210B of the protective film 200 while minimizing the generation of residual stress, for example, by using a soft material such as an abrasive cloth or by chemical etching.

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

[0032] One possible method for checking the thickness that has been removed is to measure the overall thickness of the protective film 200 each time using, for example, a spectroscopic diaphragm meter and calculate the amount of change. However, it is difficult to accurately measure minute changes of about 100 nm or less using a spectroscopic diaphragm meter. For this reason, when performing soft polishing with a conventional configuration, it is necessary to remove excess surface layer portions of the protective film 200 beyond the minimum thickness required to be removed.

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

[0034] On the other hand, because 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 H0 of protrusion 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 particles 300 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 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. Soft polishing can be terminated when the protrusion amount H0 of the particles 300 becomes equal to the predetermined target value for the removal amount. The surface 210C at this time is the surface 210 in FIG. 2. The protrusion amount H0 at this time is also 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 particles 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 soft polishing, and the protrusion amount H0 of the particles 300 may be estimated or calculated based on the size of each particle 300 in the obtained image.

[0038] 4B, the soft polishing is performed uniformly over the entire surface 210B. 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. 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 locations on the surface 210C, and soft polishing may be performed partially as needed.

[0039] In soft polishing, almost no particles 300 are removed, as shown in FIG. 4C , so the measured protrusion amount H0 of the particles 300 can be used as the amount of protective film 200 removed. However, depending on the material of the particles 300, changes in the shape of the particles 300 due to soft polishing may not be negligible. Even in such cases, there is a certain correlation between the measured protrusion amount H0 of the particles 300 and the amount of protective film 200 removed. Therefore, if this correlation is understood in advance through experiments or the like, the amount of removal 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 surface 210 can be re-polished to remove the deteriorated portion in order to reuse the structural member 10. In other words, the surface 210 can be refreshed.

[0041] The particles 300 are dispersed not only on the surface 210 of the protective film 200 but also throughout the interior thereof. 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 the protective film 200 again by an appropriate thickness.

[0042] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of the above-described specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise. [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 substrate; the protective film is formed as a film for protecting the substrate from plasma, A structural member characterized in that high-hardness particles having a higher hardness than the protective film are dispersed and disposed inside the protective film.

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

3. 3. The structural member according to claim 2, wherein the high-hardness particles protrude from the surface of the protective film by an equal amount.

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

5. 2. The structural member according to claim 1, wherein said protective coating comprises yttria and said 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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