Structure member and its manufacturing method

Abstract

A structural member capable of stably maintaining the performance of a protective film over a long period of time, and a method for manufacturing the same are provided. The structural member (10) is, The record (100) and, A protective film (200) is provided by depositing material while applying impact force to the surface (110) of a substrate (100). When the density index is used to indicate the degree of local density of the protective film (200), the value of the density index in the first part, which is the part of the protective film (200) that includes the outer surface (210), is 50% or more of the value of the density index in the second part, which is the part of the protective film (200) that is closer to the substrate (100) than the first part.

Description

Technology Field

[0001] The present invention relates to a structural member and a method for manufacturing the same. 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, in a plasma etching apparatus, a protective film is formed on the surface of a substrate constituting the inner wall of a chamber to protect the substrate from plasma. As such a protective film, oxide ceramics such as yttria or fluoride ceramics such as yttrium fluoride are used. In addition to the purpose of improving the plasma resistance of the substrate as described above, the protective film is also formed for purposes such as improving the wear resistance of the substrate.

[0003] Various film deposition methods, such as PVD or CVD, can be employed as a method for forming a protective film on the surface of a substrate. Recently, film deposition methods such as aerosol deposition and ion-assisted deposition have also been performed. These are all film deposition methods in which the protective film material is deposited on the surface of the substrate by spraying or accelerating it toward the surface of the substrate. As described in Patent Document 1 below, after the formation of the protective film by aerosol deposition or the like is completed, the surface roughness of the protective film is adjusted by polishing or the like. Prior art literature

[0004] Japanese Patent Publication No. 2008-160093 The problem to be solved

[0005] In the film formation process using the aerosol deposition method described above, the protective film material is deposited while applying impact force to the surface of the substrate. The impact force accompanying the material's arrival is applied not only to the surface of the substrate but also to the existing protective film formed up to that point.

[0006] For this reason, the portion of the protective film facing the substrate tends to become a film with relatively high density as repeated impact forces are applied after film formation. On the other hand, the outermost surface portion of the protective film tends to become a film with relatively low density because no significant impact forces are applied after formation. This low-density surface portion cannot be removed by polishing or similar methods sufficient to adjust surface roughness.

[0007] For this reason, the outermost part of the protective film, despite requiring durability against plasma and the like, is made of a film with lower density compared to other parts, and there are cases where sufficient performance cannot be secured.

[0008] In addition, during the use of a device using structural members, if the surface portion of the protective film is removed by etching or the like, the density of the surface of the protective film gradually changes accordingly. For example, in a semiconductor manufacturing device, if the condition of the inner chamber (i.e., the protective film) changes, problems such as unstable manufacturing quality may occur due to changes in the consumption of process gas.

[0009] Similarly, in the case of a protective film formed for the purpose of improving wear resistance, if the surface density changes with wear, problems such as the sliding resistance gradually changing may occur. As such, there was a possibility that conventional protective films formed using methods such as the aerosol deposition method could not stably maintain their performance over a long period of time.

[0010] The present invention has been made in consideration of these problems, and its purpose is to provide a structural member capable of stably maintaining the performance of a protective film over a long period of time, and a method for manufacturing the same. means of solving the problem

[0011] To solve the above problem, the structural member according to the present invention comprises a substrate and a protective film formed by depositing material while applying an impact force to the surface of the substrate. When the density index is used as an indicator representing the degree of local density of the protective film, the value of the density index in the first part, which is a portion including the outer surface of the protective film, is 50% or more of the value of the density index in the second part, which is a portion of the protective film closer to the substrate side than the first part.

[0012] In such a structural member, the density index of the first portion, including the outer surface of the protective film, is set to a value as high as that of the second portion on the substrate side, so sufficient performance can be achieved from the outset. Furthermore, since the difference between the density index value of the first portion and the density index value of the second portion on the inner side is relatively small, even if the surface side of the protective film is removed by etching or the like, the performance of the protective film does not change significantly. For this reason, the performance of the protective film can be maintained stably over a long period of time.

[0013] To solve the above problem, a method for manufacturing a structural member according to the present invention comprises a process of preparing a substrate, a process of forming a protective film by depositing a material while applying an impact force to the surface of the substrate, and a process of removing a surface portion of the protective film until the value of the density index in a first portion, which is a portion including the outer surface of the protective film, becomes 50% or more of the value of the density index in a second portion, which is a portion on the substrate side of the protective film, when the density index is used as an index indicating the degree of local density of the protective film.

[0014] By removing the surface portion with low density in advance from the protective film, the density index in the first portion on the surface side can be increased. Since the difference in the density index value between the first portion and the second portion becomes relatively small, it becomes possible to stably maintain the performance of the protective film over a long period of time as described above. Effects of the invention

[0015] According to the present invention, a structural member capable of stably maintaining the performance of a protective film over a long period of time, and a method for manufacturing the same can be provided. Brief explanation of the drawing

[0016] FIG. 1 is a schematic drawing illustrating a cross-section of a structural member according to the present embodiment. Figure 2 is a diagram illustrating the values ​​of the density index in each part of the protective film. FIG. 3 is a drawing for explaining a method of manufacturing a structural member according to the present embodiment. Specific details for implementing the invention

[0017] The present embodiment will be described below with reference to the attached drawings. To facilitate understanding of the explanation, the same reference numerals are used for identical components in each drawing as much as possible, and redundant descriptions are omitted.

[0018] The structural member (10) according to the present embodiment is used as a member constituting the inner wall of a processing chamber in a semiconductor manufacturing device (not shown), such as a plasma etching device, for example. Furthermore, the use of such a structural member (10) is merely an example and is not limited to semiconductor manufacturing devices.

[0019] As illustrated in FIG. 1, the structural member (10) has a substrate (100) and a protective film (200) formed to cover the surface (110) of the substrate (100). In a plasma etching apparatus, the surface (210) of the protective film (200) is exposed toward the space inside the chamber. The protective film (200) of this embodiment is provided for the purpose of protecting the substrate (100) from plasma.

[0020] The substrate (100) is a component that occupies approximately the entirety of the structural member (10). In this embodiment, the substrate (100) is composed of a ceramic sintered body containing high-purity aluminum oxide (Al2O3). The substrate (100) may be a ceramic sintered body made of a material other than the above, and depending on the use of the structural member (10), the substrate (100) may be a metal.

[0021] The protective film (200) is a film formed to cover the surface (110) of the substrate (100) as described above. In this embodiment, the protective film (200) is composed of a film containing polycrystalline yttria (Y2O3). The protective film (200) may also be a ceramic film made of a material different from the above.

[0022] The protective film (200) of the present embodiment is formed by using an aerosol deposition method on the surface (110) of the substrate (100) after firing. As is well known, in the aerosol deposition method, microparticles that are the material of the protective film (200) are dispersed in a gas to form an "aerosol," and then sprayed toward the surface (110) to cause an impact. On the surface (110), as the microparticles undergo deformation or crushing due to the impact of the collision, the microparticles combine with each other and gradually accumulate as the protective film (200). In this way, the protective film (200) is formed as a film by depositing the material while applying an impact force to the surface (110) of the substrate (100).

[0023] In FIG. 1, the portion enclosed by the dotted line DL1 is the portion including the outer surface (210) of the protective film (200). This portion is also referred to as the “first portion (201)” below. In FIG. 1, the portion enclosed by the dotted line DL2 is the portion of the protective film (200) that is closer to the substrate (100) than the first portion (201). This portion is also referred to as the “second portion (202)” below.

[0024] However, in film deposition methods such as the aerosol deposition method, where material is deposited while applying impact force to the surface of a substrate, the density of the protective film is not uniform in the depth direction, and there is a tendency for the density to decrease significantly in the outer surface portion. This is thought to be because the density of the portion of the protective film facing the substrate increases as impact force is repeatedly applied after deposition, whereas the outermost surface portion of the protective film is not subjected to significant impact force after deposition. Although the surface of the protective film is sometimes removed by polishing after deposition, such polishing is performed to adjust surface roughness, so the amount removed is minimal, and the surface portion with low density remains even after polishing.

[0025] In contrast, the structural member (10) according to the present embodiment is manufactured by a method described later, thereby making the density of the protective film (200) approximately uniform in the depth direction.

[0026] Here, an index that numerically represents the degree of local density of the protective film (200) is also referred to as the “density index” below. As a part of the protective film (200) becomes denser, the density index of that part becomes a larger value. Various indices (physical quantities, etc.) can be used as such a density index, but below, the indentation hardness measured for each part of the protective film (200) will be used as the “density index” for explanation purposes.

[0027] Indentation hardness can be measured, for example, by performing a micro-indentation hardness test (nano-indentation) on the surface of the part of the protective film (200) to be measured. For example, the indenter used in the test should be a Berkovitch indenter, and the indentation depth should be set to a fixed value of 200 nm to measure the indentation hardness (indentation hardness) HIT. As for the measurement location for HIT on the surface, it is preferable to select a surface excluding scratches or concave areas. More preferably, the surface should be a polished smooth surface to be the measurement target. The number of measurement points should be at least 25, and the average value of the 25 or more measured HITs should be taken as the hardness in the present invention. Other test methods and analysis methods, procedures for verifying the performance of the test device, and conditions required for standard reference samples may be adopted in accordance with ISO 14577.

[0028] As will be explained later, the protective film (200) is formed by using an aerosol deposition method on the surface (110) of the substrate (100) until it reaches a predetermined thickness, and then removing a portion of the surface side. The graph in FIG. 2 shows the relationship between each position in the depth direction (horizontal axis) and the value of the density index of the protective film (200) at each position at the point in time immediately after the film formation by the aerosol deposition method is completed (i.e., before removing a portion of the surface side).

[0029] "0" on the horizontal axis of Fig. 2 indicates the position of the outermost surface of the protective film (200) immediately after the membrane formation. The value of the density index (indentation hardness) of the protective film (200) at that position is ID0, which is the smallest value in the entire protective film (200).

[0030] "d" on the horizontal axis of Fig. 2 indicates the position on the side of the most material (100) among the protective film (200) immediately after the tabernacle. The value of the density index of the protective film (200) at that position is ID10, which is the largest value in the entire protective film (200).

[0031] When moving from the surface of the protective film (200) to the inner side (substrate (100) side) at position d1, the density index value of the protective film (200) rises to ID5. ID5 is 50% of the value of ID10. When moving from the protective film (200) to the inner side further than d1 at position d2, the density index value of the protective film (200) rises to ID8. ID8 is 80% of the value of ID10. When moving from the protective film (200) to the inner side further than d2 at position d3, the density index value of the protective film (200) rises to ID10. In the range from position d3 to position d within the protective film (200), the density index value is generally constant (ID10) regardless of the position.

[0032] In this way, in the protective layer (200) immediately after the tabernacle, the density index of the surface is significantly small. The value of the density index gradually increases as it goes from the surface inward, and at a position deeper than d3, it is generally constant (ID10).

[0033] Therefore, in this embodiment, after the formation of the protective film (200) is completed, a portion of the surface of the protective film (200) is removed by polishing or the like, thereby increasing the density index of the new surface portion to a high value. In other words, a portion of the surface of the protective film (200) is removed until the density index value on the surface (210) of the protective film (200) is sufficiently high.

[0034] For example, if the surface of the protective film (200) is removed up to the depth position d1 in FIG. 2, the density index value at the final surface (210) can be set to 50% (ID5) of the density index value (ID10) at the part sufficiently inward from the surface (210). If the surface of the protective film (200) is further removed, the density index value at the surface (210) can be increased. In either case, the amount of surface of the protective film (200) removed is sufficiently larger than the amount removed for the purpose of adjusting the surface roughness. The “part sufficiently inward from the surface (210)” mentioned above, that is, the minimum depth position where the density index value becomes approximately a constant value (ID10), may be the position of the interface on the substrate (10) side of the protective film (200), or it may be the position further forward (on the surface (210) side).

[0035] In this embodiment, as a result of removing the surface of the protective film (200) in this manner, the density index value in the first part (201) of FIG. 1 is 50% or more of the density index value in the second part (202). Since the density index value of the first part (201), which includes the outer surface (210) of the protective film (200), is as high as that of the second part (202), when the structural member (10) is used in a semiconductor manufacturing device, etc., it can exhibit sufficient performance from the beginning.

[0036] In addition, since the difference between the density index value of the first part (201) and the density index value of the second part (202) inside it is relatively small, even if the surface side of the protective film (200) is removed by etching or the like, the performance of the protective film (200) will not change significantly. For this reason, the performance of the protective film (200) can be maintained stably over a long period of time.

[0037] The value of the density index in the first part (201) is preferably 50% or more as in the present embodiment, but more preferably 80% or more, or 90% or more. The amount of surface removal of the protective film (200) can be appropriately adjusted to match the desired density index value.

[0038] In addition, in this embodiment, as shown in FIG. 2, the value of the density index in each part of the protective film (200) gradually increases as it goes from the surface (210) side toward the substrate (100) side. This change in the value of the density index may be a smooth change, but it may also be a stepwise change. In addition, in some parts, the value of the density index may change in the opposite direction to the above. For example, the value of the density index near the interface that is closer to the substrate (100) than the second part of the protective film (200) may be smaller compared to the density index of the second part.

[0039] FIG. 2 schematically illustrates the relationship between the depth position and the density index in the protective film (200). It has been confirmed that the relationship between the two is generally as shown in FIG. 2, regardless of the material of the protective film (200) or the type of parameter selected as the density index. Specific measurement examples of this relationship are shown below.

[0040] The inventors used alumina (Al2O3) as the material for the substrate (100) and yttria (Y2O3) as the material for the protective film (200), and then produced a sample of the structural member (10). The protective film (200) was formed by an aerosol deposition method. Immediately after the formation was completed, the thickness of the protective film (200) was 10.5 μm.

[0041] As a density indicator, the indentation hardness of each part of the protective film (200) was used. Immediately after the formation of the protective film (200) was completed and before removing the surface, the indentation hardness on the surface was measured and was 2.6 GPa. That is, for the sample of this structural member (10), it was confirmed that the density indicator, i.e., the value of ID0, at the depth position of “0” in FIG. 2 was 2.6 GPa.

[0042] After that, the removal of the surface of the protective film (200) and the measurement of the indentation hardness on the new surface after removal were repeated.

[0043] After the amount of removal from the surface after film formation (i.e., the initial) reached 1.25 μm, the indentation hardness on the surface after removal was measured to be 10.5 GPa. After that, after the amount of removal from the surface after film formation reached 2.0 μm, the indentation hardness on the surface after removal was measured to be 10.8 GPa. Subsequently, it was confirmed that even if the surface of the protective film (200) was further removed, the indentation hardness on the surface after removal hardly changed from 10.8 GPa. That is, in the sample of this structural member (10), the depth position slightly exceeding "d3" in FIG. 2 is approximately 2 μm, and it was confirmed that the value of the density index, i.e. ID10, at that position is 10.8 GPa.

[0044] In the sample of this structural member (10), the new surface and the area near it, where only 1.25 μm of the surface after film formation is removed, correspond to the first part (201) of FIG. 1. Additionally, the part at a depth of 2.0 μm from the original surface before removal corresponds to the second part (202) of FIG. 1.

[0045] The density index value (10.5 GPa) of the first part (201) is approximately 97% of the density index value (10.8 GPa) of the second part (202). In this way, it was confirmed that in the above sample, if the surface of the protective film (200) after film formation is removed by 1.25 μm or more, the difference in density index values ​​between the first part (201) and the second part (202) becomes very small, and the performance of the protective film (200) can be stably maintained over a long period of time.

[0046] A method for manufacturing a structural member (10) is described with reference to FIG. 3. First, as shown in (A) of FIG. 3, a substrate (100) is prepared. It is preferable that the surface roughness, etc., of the surface (110) of the substrate (100) be adjusted in advance so that a protective film (200) can be stably formed later.

[0047] Next, as shown in (B) of FIG. 3, a protective film (200) is formed by depositing material while applying impact force to the surface (110) of the substrate (100). As for this film formation method, an aerosol deposition method may be used as in the present embodiment, but other methods such as ion-assisted deposition may also be used. Regardless of which method the film is formed, the density index values ​​in each part of the formed protective film (200) have a distribution similar to that shown in FIG. 2. In FIG. 3 (B), the symbol "210S" is attached to the surface of the protective film (200) at the time when the film formation is completed.

[0048] Next, as illustrated in (C) of FIG. 3, the surface portion of the protective film (200) is removed. Here, the portion including the surface (210S) of the protective film (200) is removed until the density index value in the first portion (201) of FIG. 1 is 50% or more of the density index value in the second portion (202) of FIG. 1. This process may be performed while measuring the density index value on the surface of the protective film (200) each time, but the depth to which the surface should be removed may be determined in advance through experiments, etc.

[0049] The removal of the surface (210S) of the protective film (200) may be performed by mechanical grinding or polishing, but may also be performed by dry etching or wet etching. Afterwards, if necessary, the surface roughness of the surface (210) may be adjusted.

[0050] The protective film (200) may be provided for the purpose of protecting the substrate (100) from plasma, as in the present embodiment, but may also be provided for the purpose of adding other functions to the substrate (100). For example, it may be a film for improving the wear resistance of the substrate (100).

[0051] In this embodiment, indentation hardness was used as the density indicator, but as described above, various indicators can be used as the density indicator. For example, any of the crystallite size, porosity, fluorine content, three-dimensional roughness parameter, acid etching amount, plasma etching amount, hydrogen content, Raman, XPS intensity, residual stress, light transmittance or reflectance, and thermal diffusivity of the protective film (200), or an indicator related to these, can be used as the density indicator. Even when any of the above indicators are used as the density indicator, it is possible to draw a graph similar to that shown in FIG. 2.

[0052] Although the measurement methods for each indicator are exemplified below, even when using any indicator as a density indicator, the indicator can be measured under the same conditions and using the same measurement method as much as possible for each of the first part, which includes the surface (210) of the protective film (200), and the second part, which is the part on the substrate (100) side. As a result, if the value of the density indicator in the first part is 50% or more, preferably 80% or more, of the value of the density indicator in the second part, the effect described above can be achieved. Furthermore, each measurement condition, etc. shown below has been confirmed to be suitable at least when the protective film (200) is formed by the aerosol deposition method.

[0053] Determinant Size

[0054] A parameter whose value increases as the crystallites of the protective film (200) become smaller can be used as the value of the density index. For example, the reciprocal of the average crystallite size measured as follows can be used as such a parameter. The "average crystallite size" is a value calculated from the average diameter of 15 crystallites by circular approximation in an image taken with a transmission electron microscope (TEM) at a magnification of 400,000x or more, for example. At this time, crystallites can be identified more clearly by making the sample thickness sufficiently thin, such as 30nm, during focused ion beam (FIB) processing. It is preferable to appropriately select the shooting magnification in the range of 400,000x or more. As an example of the case where the protective film (200) is formed by the aerosol deposition method, if the crystallite size of the second part is 10nm, it is preferable that the crystallite size of the first part be smaller than 20nm.

[0055] Porosity

[0056] A parameter whose value increases as the occupancy rate of pores (i.e., porosity) in the cross-section when the protective film (200) is cut decreases can be used as the value of the density index. For example, a value obtained by subtracting the porosity measured as follows from 100 (%) can be used as such a parameter. When measuring the porosity, for example, the cross-section of the protective film (200) is observed using a scanning electron microscope (Hitachi Seisakusho / S4100) and the image is digitized. Then, using image processing software (Media Cybernetics / Image-Pro PLUS), the pore occupancy area in a certain area of ​​the observation field is measured and calculated and converted into an area percentage. If the porosity value obtained in this way is, for example, 10%, the density index is calculated as 90%.

[0057] <Fluoride Amount>

[0058] A parameter whose value increases as the amount of fluorine contained in the protective film (200) decreases can be used as the value of the density index. For example, the reciprocal of the accumulated value of the amount of fluorine measured as follows can be used as such a parameter. First, the part of the protective film (200) to be measured is exposed, and the surface of said part is exposed to plasma under certain conditions. Then, the accumulated value of the amount of fluorine detected within a predetermined time when said surface is etched is calculated. When exposing to plasma, for example, an inductively coupled plasma reactive ion etching device (MUC-21 RV-APS-SE / manufactured by Sumitomo Seimitsu Kogyo Co., Ltd.) can be used. At this time, SF6 gas is supplied around the protective film (200) at a constant flow rate (for example, 100 sccm), and the pressure is maintained at 0.5 Pa. The plasma output should be set to Coil / Bias = 1500 / 0 (W). The measurement of the fluorine content during etching can be performed using an XPS device manufactured by K-Alpha / Thermo Fisher. Argon ions should be used as the etching source, and the detection time should be set to 145 seconds. At that time, the fluorine content should be measured every 5 seconds, and the obtained values ​​should be accumulated.

[0059] <3D Illuminance Parameters>

[0060] The part of the protective film (200) to be measured is exposed, and plasma is irradiated onto the surface of the said part under predetermined conditions. After that, the surface roughness of said surface is measured. A parameter whose value increases as the surface roughness obtained in this way becomes smaller can be used as a density indicator. As such a parameter, for example, the reciprocal of the "arithmetic mean height (Sa)" described in paragraph 0035 of Japanese Patent Publication No. 2020-012192 can be used.

[0061] <Acid Etching Amount>

[0062] The portion of the protective film (200) to be measured is exposed, and the surface of the said portion is exposed to hydrochloric acid under certain conditions. At this time, a parameter whose value increases as the depth dimension (amount of acid etching) of the etched portion of the protective film (200) increases can be used as the value of the density index. For example, the reciprocal of the amount of acid etching measured as above can be used as such a parameter. As for the "certain conditions," for example, the room temperature is 19.2°C, the concentration of hydrochloric acid is 5.7% (1.6N), the temperature of the hydrochloric acid is 16.8±0.1°C, and the exposure time to the hydrochloric acid is any one of 1 minute, 3 minutes, 7 minutes, 15 minutes, and 30 minutes. The temperature of the hydrochloric acid can be measured each time before the etching process using an AND AD-6525 thermometer.

[0063] Plasma Etching Amount

[0064] Instead of etching using acid as described above, etching using plasma may be performed. That is, a parameter whose value increases as the amount of etching increases when the portion of the protective film (200) to be measured is exposed and the surface of said portion is exposed to plasma under certain conditions can be used as the value of the density index. For example, the reciprocal of the amount of etching measured as described above can be used as such a parameter. As a device for exposing the protective film (200) to plasma, for example, an inductively coupled plasma reactive ion etching device (MUC-21 RV-APS-SE / manufactured by Sumitomo Seimitsu Kogyo Co., Ltd.) can be used. As "certain conditions," SF6 gas is supplied around the protective film (200) at a constant flow rate (e.g., 100 sccm) while maintaining the pressure at 0.5 Pa. The plasma output should be set to Coil / Bias = 1500 / 750 (W). The plasma exposure time should be 60 minutes. The amount of etching can be measured using, for example, a laser microscope (VHX-1100 / Keyence).

[0065] <Amount of hydrogen>

[0066] A parameter whose value increases as the amount of hydrogen contained in each part of the protective film (200) decreases can be used as the value of the density index. For example, the reciprocal of the measured amount of hydrogen can be used as such a parameter. As a method for measuring the amount of hydrogen, for example, the method described in paragraphs 0042 to 0053 of Japanese Patent Publication No. 2020-012192 or the method described in paragraphs 0062 to 0074 of the same publication can be used.

[0067] Raman

[0068] For the protective film (200), a value representing the intensity of scattered light detected using a Raman spectrometer can be used as a value of the density index.

[0069] <XPS의 강도>

[0070] When X-ray photoelectron spectroscopy (XPS) is performed on the protective film (200), the value representing the photoelectron intensity can be used as the value of the density index.

[0071] Residual stress

[0072] A parameter whose value increases as the residual stress in each part of the protective film (200) decreases can be used as the value of the density index. The residual stress can be measured, for example, using an X-ray residual stress measuring device. Alternatively, the residual stress value may be calculated from the amount of change in the lattice plane spacing by performing X-ray diffraction.

[0073] Light transmittance

[0074] The part of the protective film (200) to be measured is exposed, and the value of the linear transmittance of light on the surface of said part can be used as the value of the density index. The measurement is performed using a spectroscopic altimeter, and the wavelength of the light can be 200 to 800 nm.

[0075] Reflectance of light

[0076] The part of the protective film (200) to be measured is exposed, and a parameter whose value increases as the light reflectance on the surface of the said part decreases can be used as the value of the density index. The measurement can be performed using a spectroscopic altimeter, and the wavelength of the light can be 200 to 800 nm.

[0077] <Thermal diffusivity>

[0078] With respect to the protective film (200), the value of the thermal diffusivity when instantaneously localized heating is performed with a pulse laser, etc., can be used as a value of the density index. For measuring the thermal diffusivity, for example, the laser flash method or the pulsed light heating thermoreflectance method can be used.

[0079] The embodiments described above have been explained with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications appropriately made by a person skilled in the art to these specific examples are also included within the scope of the present disclosure, provided that they possess the features of the present disclosure. Each element, arrangement, condition, shape, etc., provided in each of the aforementioned specific examples are not limited to those exemplified and can be appropriately modified. Each element provided in each of the aforementioned specific examples can be appropriately combined as long as no technical contradiction arises. Explanation of the symbols

[0080] 10: Structural member 100: Entry 110: Surface 200: Shield 210: Surface

Claims

Claim 1 A structural member comprising a substrate and a protective film formed by depositing material while applying impact force to the surface of the substrate, wherein, when an index indicating the degree of local density of the protective film is used as a density index, the value of the density index in a first portion including the outer surface of the protective film is 50% or more of the value of the density index in a second portion including the interface on the substrate side of the protective film. Claim 2 A structural member according to claim 1, characterized in that the density index is indentation hardness. Claim 3 A structural member according to claim 1, characterized in that the protective film is a film formed by an aerosol deposition method. Claim 4 A method for manufacturing a structural member, characterized by comprising: a process of preparing a substrate; a process of forming a protective film by depositing a material while applying an impact force to the surface of the substrate; and a process of removing a surface portion of the protective film until the value of the density index in a first portion, which includes the outer surface of the protective film, becomes 50% or more of the value of the density index in a second portion, which includes the interface on the substrate side of the protective film, when the density index is used to indicate the degree of local density of the protective film.

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