structural member

Abstract

Provided is a structural member capable of improving the adhesion of a protective film to the surface of a base material. The structural member (10) includes a base material (100) formed of a polycrystalline material, and a protective film (200) covering the surface (110) of the base material (100). In a cross section of the base material (100) cut perpendicular to the surface (110), in the crystal grains (150) constituting the base material (100), when the average of the respective cross-sectional areas of a plurality of crystal grains 150F exposed to the surface (110) is taken as a first cross-sectional area, and the average of the respective cross-sectional areas of a plurality of crystal grains 150B located inside the surface (110) is taken as a second cross-sectional area, in the structural member (10), the first cross-sectional area is smaller than the second cross-sectional area.

Description

Technical Field

[0001] This invention relates to a structural component. Background Technology

[0002] Components constituting a semiconductor manufacturing apparatus, such as the inner walls of chambers, require plasma resistance. Therefore, as such components, as described in Patent Document 1 below, structural components with a protective film formed on the surface of a substrate are typically used. As the substrate, a polycrystalline material such as alumina is typically used, and as the protective film, a material such as yttrium oxide is typically used.

[0003] Patent documents Patent Document 1: Japanese Patent Application Publication No. 2007-321183 Summary of the Invention

[0004] In the aforementioned structural components, to prevent the protective film exposed to plasma from aging and becoming particles that splatter, it is necessary to improve the adhesion between the protective film and the substrate. Regarding the question of how to pre-determine the surface characteristics of the substrate to form a protective film with high adhesion, there is still room for improvement in existing structural components.

[0005] The present invention was made in view of the following problems, and its object is to provide a structural component that can improve the adhesion of the protective film to the surface of the substrate.

[0006] To address the aforementioned problems, the structural member of the present invention comprises: a substrate formed of a polycrystalline material; and a protective film covering the surface of the substrate. In a cross-section perpendicular to the surface of the substrate, when the average cross-sectional area of ​​the plurality of crystalline particles constituting the substrate is taken as the first cross-sectional area, and the average cross-sectional area of ​​the plurality of crystalline particles located inside the surface is taken as the second cross-sectional area, in this structural member, the first cross-sectional area is smaller than the second cross-sectional area.

[0007] If the surface properties of the substrate are pre-adjusted before film formation to make the first cross-sectional area smaller than the second cross-sectional area, the proportion of the cross-section of each crystalline particle (that is, the surface inside the grain, not the grain boundary) on that surface will be larger. The cross-section of the crystalline particle is a surface that is more prone to plastic deformation than the grain boundary, and it is also an active surface. Therefore, by using methods such as aerosol deposition or physical vapor deposition, it is possible to form a film with high adhesion on the surface of the substrate.

[0008] According to the present invention, a structural component capable of improving the adhesion of the protective film to the surface of the substrate can be provided. Attached Figure Description

[0009] Figure 1It is a diagram that schematically represents the cross-section of the structural member involved in this embodiment. Figure 2 This is a diagram used to illustrate the surface characteristics, etc., of the substrate of the structural member involved in this embodiment. Figure 3 This is a diagram used to illustrate the surface characteristics, etc., of the substrate of the structural member involved in this embodiment. Figure 4 This is a diagram used to illustrate the surface characteristics, etc., of the substrate of the structural member involved in this embodiment. Figure 5 This is a diagram used to illustrate the surface characteristics, etc., of the substrate of the structural member involved in the comparative example. Symbol Explanation 10 - Structural component; 100 - Substrate; 110 - Surface; 150, 150A, 150B - Crystalline particles; 200 - Protective film. Detailed Implementation

[0010] Hereinafter, this embodiment will be described with reference to the accompanying drawings. For ease of understanding, the same symbols will be used to label the same components as much as possible in each drawing, and repeated descriptions will be omitted.

[0011] The first embodiment will be described. The structural member 10 involved in this embodiment is configured as a component for a semiconductor manufacturing apparatus, such as a plasma etching apparatus. Specifically, the structural member 10 serves as a component for the inner wall of a processing chamber provided in a semiconductor manufacturing apparatus. Furthermore, the use of such a structural member 10 is merely an example. The structural member 10 may also be, for example, a component disposed inside the processing chamber provided in a semiconductor manufacturing apparatus, such as a focusing ring.

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

[0013] The substrate 100 is a component that occupies approximately the entirety of the structural member 10. The substrate 100 is formed of a polycrystalline material. In this embodiment, the substrate 100 is a ceramic sintered body containing high-purity alumina (Al2O3) as the main component, but it can also be a component formed of other polycrystalline materials. In addition, although the surface 110 of the substrate 100 is a flat surface in this embodiment, it can also be a curved surface. Furthermore, a slope can be provided on a portion of the surface 110.

[0014] As previously described, the protective film 200 is formed to protect the substrate 100 from plasma. The protective film 200 is formed to cover the entire surface 110 of the substrate 100. Although the protective film 200 is formed, for example, from a material containing yttrium oxide (Y2O3) as a main component, it can also be formed using other materials. Although the protective film 200 of this embodiment is formed by aerosol deposition, it can also be formed by other film-forming methods such as physical vapor deposition (PVD).

[0015] In this specification, "major component" refers to the compound with the highest content in the object (e.g., substrate 100). Specifically, "major component" refers to a compound whose volume or mass percentage content is higher than any other compound contained in the object when quantitative or semi-quantitative analysis of the object is performed using X-ray diffraction (XRD). For example, in the substrate 100 of this embodiment, the proportion of the major component (alumina) is greater than 50% by volume or mass. This proportion can be greater than 70%, greater than 90%, or even 100%.

[0016] The thickness of the protective film 200 is appropriately set according to the length of the period during which durability is required. In this embodiment, the thickness of the protective film 200 is 15 μm or less.

[0017] However, in structural components 10 used in semiconductor manufacturing apparatuses, it is required to improve the adhesion between the protective film 200 and the substrate 100 in order to prevent the protective film 200 exposed to plasma from aging and becoming particles that splatter. Therefore, it is considered important to properly adjust the characteristics of the surface 110 of the substrate 100 before forming the protective film 200. "Characteristics of the surface 110" refers, for example, to the surface roughness of the surface 110.

[0018] However, through previous experiments, the inventors have confirmed that if the characteristics of the surface 110 are adjusted only to keep the arithmetic mean roughness (Ra) of the surface 110 below a specified value, it is sometimes impossible to stably improve the adhesion of the protective film 200.

[0019] Therefore, the inventors turned their attention to the cross-section when the substrate 100 is cut perpendicular to the surface 110, i.e. Figure 1 Crystalline particles 150 constituting the substrate 100 on such a cross section Figure 1 Not shown in the image, please refer to the diagram. Figure 2 The shape distribution of (etc.). As a result, new indicators were discovered as described below.

[0020] Figure 2The cross-section shown is a portion of the cross-section when the substrate 100 is cut perpendicular to surface 110. The figure also shows cross-sections of the plurality of crystalline particles 150 constituting the substrate 100. Lines drawn between adjacent crystalline particles 150 represent the interfaces between the crystalline particles. Additionally, in Figure 2 In the cross-section, the line representing surface 110 is drawn with thick lines.

[0021] For ease of explanation, among the plurality of crystal particles 150, a portion of the crystal particles 150 exposed on the surface 110 will be referred to as "crystal particles 150F". In addition, all the remaining crystal particles 150, that is, all the crystal particles 150 located inside the surface 110, will be referred to as "crystal particles 150B". Figure 2 In the diagram, only the cross-section of crystalline particle 150F is depicted with a shaded line.

[0022] exist Figure 2 At the time shown, the protective film 200 has not yet been formed on the substrate 100. Furthermore, no grinding or other treatments to adjust the properties of the surface 110 have been performed. In most of the plurality of crystalline particles 150F exposed on the surface 110, their cross-sectional shape continues to maintain the initial cross-sectional shape immediately after sintering. Therefore, the interface of the crystalline particles 150F is present in most of the surface 110. In addition, the average cross-sectional area of ​​each crystalline particle 150F is approximately equal to the average cross-sectional area of ​​each crystalline particle 150B.

[0023] By performing a process that removes a portion of the surface 110 side of the substrate 100, it is possible to... Figure 2 The state shown becomes Figure 3 The state shown. Figure 2 In the diagram, the dashed line DL represents the boundary between the portion removed by the above process and the portion not removed. Such a process can be achieved, for example, by precision grinding using finer abrasive grains than usual.

[0024] In multiple crystalline particles 150, Figure 2 The particles that become crystalline particles 150F (shown as shaded lines) are in... Figure 3 In its original state, it remains a crystalline particle 150F. However, since a portion of each crystalline particle 150F has been removed, its cross-sectional shape has changed from the initial cross-sectional shape. Therefore, in most of the surface 110, a new surface is presented within the grains of the crystalline particle 150F, rather than the interface of the crystalline particle 150F. In addition, the average cross-sectional area of ​​each crystalline particle 150F is smaller than the average cross-sectional area of ​​each crystalline particle 150B.

[0025] Furthermore, in Figure 3In the example, although the new surface 110 is drawn as a straight line, the shape of surface 110 can also be non-linear. Furthermore, although... Figure 3 The crystalline particles at time 150F can be from Figure 2 From the very beginning, it was a crystalline particle of 150F, but it could also be... Figure 2 The moment is the particle of crystallization 150B. In either case, it is sufficient as long as most of the surface 110 is occupied by the new surface inside the grain of crystallization 150.

[0026] For example Figure 3 The properties of the substrate 100, having thus been adjusted, for example by forming a protective film 200 using aerosol deposition, become... Figure 4 The state of completion Figure 1 Structural component 10 of the structure shown.

[0027] As is well known, in the aerosol deposition method, the material of the protective film 200, i.e., the microparticles, is dispersed in a gas to form an "aerosol," which is then sprayed from a nozzle onto the surface 110 to cause collisions. On the surface 110, the impact of the collisions causes the microparticles to deform or break, so the microparticles gradually accumulate to form the protective film 200 while combining with each other.

[0028] Figure 3 At any given moment, the surface 110 is largely occupied by new surfaces within the grains of the crystalline particles 150. Such surfaces are more prone to plastic deformation compared to the interfaces of the crystalline particles 150, and are also surfaces with higher chemical reactivity. Therefore, when... Figure 3 When a protective film 200 is formed on surface 110 by aerosol deposition, the surface 110 is more prone to plastic deformation when particles collide with it, thus the particles are more likely to be firmly fixed on the surface 110. As a result, the adhesion of the protective film 200 to the surface 110 is significantly improved compared to the past.

[0029] The same applies when forming a protective film 200 using physical vapor deposition. Because... Figure 3 The surface 110 has high chemical reactivity, making it easy for raw materials, such as atoms, to adhere or accumulate on it. As a result, a highly adhesive protective film 200 can be formed on the surface 110.

[0030] Assuming that surface 110 is in a state of holding Figure 2 When the protective film 200 is formed under the condition of [condition], most of the protective film 200 will be formed at the interface of the crystalline particles 150F. That is, most of the protective film 200 will be formed on the surface 110, which is difficult to plastically deform and has low chemical reactivity. Therefore, [compared to] [other conditions], Figure 4Compared to the embodiment shown, the adhesion of the protective film 200 is reduced.

[0031] Furthermore, even if a portion of the surface 110 of the substrate 100 is removed before the protective film 200 is formed, it does not necessarily always become Figure 3 The state. For example, even for Figure 2 The substrate 100 is ground. Depending on the different grinding conditions, the new surface inside the grain of the crystal particles 150 may not be presented on the surface 110. Due to the shedding of the crystal particles 150F, they may be in a state where other interfaces are presented.

[0032] For example in Figure 5 In the comparative examples shown, Figure 2 The crystalline particles 150F, depicted with shaded lines, detach due to grinding or other processes, forming a protective film 200 that covers the surface 110 of the newly exposed crystalline particles 150F. In this example, most of the surface 110 still serves as the interface for the crystalline particles 150F. That is, with... Figure 2 Surface 110 is the same, Figure 5 Surface 110 becomes a surface that is not easily plastically deformed and has low chemical reactivity. As a result, the adhesion of the protective film 200 formed on this surface is reduced.

[0033] As mentioned above, simply removing a portion of the surface 110 of the substrate 100 may not necessarily improve the adhesion of the protective film 200. To improve the adhesion of the protective film 200, the key is to expose more new surfaces on the surface 110 of the substrate 100, revealing the interior of the crystal grains 150 within them.

[0034] In such Figure 2 or Figure 3 Among the multiple crystalline particles 150 on such a cross-section, the average cross-sectional area of ​​each of the multiple crystalline particles 150F is hereinafter referred to as the "first cross-sectional area". Furthermore, in situations such as... Figure 2 or Figure 3 Among the multiple crystalline particles 150 on such a cross-section, the average cross-sectional area of ​​each of the multiple crystalline particles 150B is hereinafter referred to as the "second cross-sectional area". In this embodiment, in order to make... Figure 3 The properties of surface 110 were adjusted to reflect the state of the surface, resulting in the first cross-sectional area being smaller than the second cross-sectional area.

[0035] If the characteristics of surface 110 are adjusted in advance to ensure that the first and second cross-sectional areas meet the aforementioned parameters, a new surface with more crystalline particles 150 within the grains can be formed on surface 110. As a result, the adhesion of the protective film 200 to the surface 110 of the substrate 100 can be significantly improved. More preferably, if the characteristics of surface 110 are adjusted in advance such that the first cross-sectional area is less than 70% of the second cross-sectional area, the adhesion of the protective film 200 can be significantly improved.

[0036] In addition to precision grinding, which has been described previously, a variety of other methods can be used to adjust the properties of surface 110.

[0037] Preferably, the arithmetic mean roughness (Ra) of the surface 110 is adjusted to below 0.1 μm before the protective film 200 is formed. By pre-forming the surface 110 into such a smooth surface, the adhesion of the protective film 200 can be improved more reliably. However, simply controlling the arithmetic mean roughness (Ra) of the surface 110 to below 0.1 μm may sometimes fail to ensure the adhesion of the protective film 200, as previously stated. Even if the arithmetic mean roughness (Ra) of the surface 110 is below 0.1 μm, such as Figure 5 As shown in the example, it is also possible that most of the surface 110 becomes the interface of the crystalline particles 150.

[0038] The arithmetic mean roughness of surface 110 can be measured using various known methods. Even after the protective film 200 has been formed, the arithmetic mean roughness of surface 110 can be measured, for example, by the following methods.

[0039] First, the structural member 10 is cut perpendicular to surface 110, and then... Figure 4 The same cross-section is used as the measurement object. A specified range of this cross-section is photographed using a laser microscope. For example, a Keyence VK-X3000 laser microscope can be used. For instance, using a 50x objective lens, a 1000x image can be obtained.

[0040] Next, based on the contour data obtained from the above image, the arithmetic mean roughness Ra of surface 110 is calculated. The "reference length," representing the measurement range, can be set to, for example, 250 μm. Additionally, the cutoff wavelength λs is set to 0.8 μm, and the calculation is performed using stylus mode. In this case, the stylus tip radius is set to 2 μm, and the stylus tip angle is set to 60°. Measurements are taken at 20 distinct locations on surface 110, and the average of the obtained values ​​is used to calculate the arithmetic mean roughness Ra.

[0041] The present embodiment has been described above with reference to specific examples. However, the present invention is not limited to these specific examples. Regarding these specific examples, any design modifications made by those skilled in the art that possess the features of the present invention are also included within the scope of the present invention. The elements, their configurations, conditions, shapes, etc., of the foregoing specific examples are not limited to the illustrated content, but can be appropriately modified. As long as there is no technical contradiction, the elements of the foregoing specific examples can be appropriately changed and combined.

Claims

1. A structural component, characterized in that, It possesses: a substrate formed of polycrystalline materials; and a protective film covering the surface of the substrate, On the cross-section when the substrate is cut perpendicular to the surface Among the crystalline particles constituting the substrate, when the average cross-sectional area of ​​each of the plurality of crystalline particles exposed on the surface is taken as the first cross-sectional area, And when the average cross-sectional area of ​​each of the plurality of crystal particles located inside the surface is taken as the second cross-sectional area, The first cross-sectional area is smaller than the second cross-sectional area.

2. The structural member according to claim 1, characterized in that, The first cross-sectional area is less than 70% of the second cross-sectional area.

3. The structural member according to claim 1, characterized in that, The protective film is formed by aerosol deposition.

4. The structural member according to claim 1, characterized in that, The protective film is formed by physical vapor deposition.

5. The structural member according to claim 1, characterized in that, The arithmetic mean roughness of the surface is less than 0.1 μm.

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