Structural members

Abstract

To provide a structural member that has sufficient durability against plasma. [Solution] The structural member 10 comprises a base material 100 and a protective film 200 covering the surface 110 of the base material 100. The protective film 200 mainly contains lanthanum zircon oxide, and the indentation hardness of the protective film 200 is greater than 7.2 GPa.

Description

Technical Field

[0001] The present invention relates to a structural member.

Background Art

[0002] Members constituting a semiconductor manufacturing apparatus, such as members of the inner wall of a chamber, etc., are required to have durability against plasma. For this reason, as such members, it has generally become common to use a structural member in which a protective film is formed on the surface of a base material, as described in Patent Document 1 below, for example. As the protective film, oxide ceramics such as yttria are often used.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventors of the present invention have been studying the use of lanthanum zirconium oxide as a material for the protective film and further enhancing the durability of the protective film against plasma.

[0005] The present invention has been made in view of such problems, and an object thereof is to provide a structural member having sufficient durability against plasma.

Means for Solving the Problems

[0006] In order to solve the above problems, the structural member according to the present invention includes a base material and a protective film that covers the surface of the base material. The protective film contains lanthanum zirconium oxide as a main component, and the indentation hardness of the protective film is greater than 7.2 GPa.

[0007] Experiments conducted by the inventors confirmed a correlation between the indentation hardness of a protective film mainly composed of lanthanum zirconate oxide and the durability of the protective film against plasma. Furthermore, it was confirmed that the durability of the protective film against plasma can be sufficiently enhanced by forming it such that its indentation hardness exceeds 7.2 GPa. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a structural member that has sufficient durability against plasma. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing a cross-section of a structural member. [Figure 2] This figure shows the relationship between the indentation hardness of the protective film and the durability of the protective film against plasma. [Figure 3] This figure shows the relationship between the indentation hardness of the protective film and the durability of the protective film against plasma. [Figure 4] This table shows a list of film formation conditions and other factors used when forming a protective film. [Figure 5] This is a diagram illustrating the surface shape of the protective film. [Figure 6] This is a diagram illustrating the porosity of the protective film. [Figure 7] This table shows a list of film formation conditions and other factors used when forming a protective film. [Figure 8] This figure shows the change in surface roughness of the protective film over time when the protective film is immersed in hydrochloric acid. [Modes for carrying out the invention]

[0010] This 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 whenever possible, and redundant explanations are omitted.

[0011] The structural member 10 according to this embodiment is configured as a component for semiconductor manufacturing equipment, such as a plasma etching apparatus. Specifically, the structural member 10 is a component used as the inner wall of a processing chamber in semiconductor manufacturing equipment. However, this application of the structural member 10 is merely an example. The structural member 10 may also be a component placed inside the processing chamber of semiconductor manufacturing equipment, such as a focus ring.

[0012] As shown in Figure 1, the structural member 10 comprises a base material 100 and a protective film 200. In a plasma etching apparatus, the surface 210 of the protective film 200 is exposed to the space inside the processing chamber. The protective film 200 is provided for the purpose of protecting the surface 110 of the base material 100 from plasma.

[0013] The base material 100 is a component that occupies approximately the entirety of the structural member 10. In this embodiment, the base material 100 is a ceramic sintered body containing high-purity aluminum oxide (Al2O3), but it may be a different type of ceramic, or a component other than ceramic (for example, a metal component). Also, in this embodiment, the surface 110 of the base material 100 is a flat surface, but it may be a curved surface or the like. Furthermore, a slope may be provided on a part of the surface 110.

[0014] As mentioned above, the protective film 200 is a film formed to protect the substrate 100 from plasma. The protective film 200 is formed to cover the entire surface 110 of the substrate 100. The protective film 200 is made of a material mainly composed of lanthanum zirconate oxide. Specifically, the lanthanum zirconate oxide is La2Zr2O7. The ratio of the number of lanthanum (La) atoms, zirconium (Zr) atoms, and oxygen (O) atoms in the protective film 200 may differ from that described above. In this embodiment, the protective film 200 is a film formed using the aerosol deposition method, but it may also be a film formed using other film formation methods.

[0015] In this specification, the "main component" refers to the compound most contained in the object (here, the protective film 200). Specifically, the "main component" refers to a compound that is confirmed to be relatively more contained in terms of volume ratio or mass ratio than any other compound contained in the object when quantitative analysis or semi-quantitative analysis using X-ray diffraction (XRD) is performed on the object.

[0016] In the protective film 200 of this embodiment, the proportion occupied by the main component (lanthanum zirconium oxide) is greater than 50% in terms of volume ratio or mass ratio. This proportion may be greater than 70%, may be greater than 90%, or may be 100%.

[0017] The thickness of the protective film 200 is appropriately set according to the length of the period for which durability is required, etc. In this embodiment, the thickness of the protective film 200 is 15 μm or less.

[0018] The inventors of the present invention decided to use lanthanum zirconium oxide as in this embodiment as the material of the protective film 200, and have been proceeding with studies on further enhancing the durability of the material against plasma. As a result, it was confirmed that there is a correlation between the indentation hardness of the protective film 200 containing lanthanum zirconium oxide as the main component and the durability of the protective film 200 against plasma.

[0019] The indentation hardness of the protective film 200 was measured by performing a very small indentation hardness test (nanoindentation) on the surface 210 of the protective film 200 formed on the base material 100. The indenter was a Berkovich indenter, the indentation depth was set to a fixed value of 200 nm, and the indentation hardness (indentation hardness) was measured at multiple locations on the surface 210. Each measurement location was a part of the surface 210 without scratches or dents. Prior to the measurement of the indentation hardness, if the surface 210 is polished and smoothed, the indentation hardness can be measured with higher accuracy. The number of measurement locations was at least 10 or more, and the average value of the indentation hardness measured at each location was calculated as the indentation hardness of the protective film 200. For other specific test methods, analysis methods, procedures for verifying the performance of test equipment, and conditions required for standard reference samples, etc., the methods specified in ISO 14577 were used.

[0020] The inventors prepared a plurality of samples of the structural member 10 having different film-forming conditions of the protective film 200, and for each protective film 200, the indentation hardness was measured, the durability against plasma was evaluated, etc. In evaluating the durability of the protective film 200 against plasma, the surface 210 of each protective film 200 was exposed to a plasma atmosphere using an inductively coupled reactive ion etching (ICP-RIE) apparatus not shown. As the conditions for exposing the surface 210 to the plasma atmosphere, the following two conditions were used.

[0021] Under the first condition, a 4-inch silicon wafer was held by electrostatic chuck within the chamber of an inductively coupled reactive ion etching apparatus. A sample of the structural member 10 to be evaluated was placed on the silicon wafer. Subsequently, plasma was generated in the chamber to expose the surface 210 of the protective film 200 to a plasma atmosphere. SF6 was used as the process gas and supplied to the chamber at a flow rate of 100 sccm. The pressure inside the chamber was adjusted to 0.5 Pa. The exposure time was 30 minutes. The power output was set to 1500W for the ICP coil output and 750W for the bias output. The test in which the surface 210 of the protective film 200 is exposed to a plasma atmosphere under the first condition described above will also be referred to as the "first standard plasma test" below. In the first standard plasma test, as described above, the bias output was set to 750W, causing the plasma to be drawn towards the protective film 200 and subjected to etching of the protective film 200.

[0022] Under the second condition, a 4-inch silicon wafer was held by electrostatic chuck within the chamber of an inductively coupled reactive ion etching apparatus. A sample of the structural component 10 to be evaluated was placed on the silicon wafer. Subsequently, plasma was generated in the chamber to expose the surface 210 of the protective film 200 to a plasma atmosphere. SF6 was used as the process gas and supplied to the chamber at a flow rate of 100 sccm. The pressure inside the chamber was adjusted to 0.5 Pa. The exposure time was 60 minutes. The power output was set to 1500W for the ICP coil output and the bias output was turned OFF (i.e., 0W). The test in which the surface 210 of the protective film 200 is exposed to a plasma atmosphere under the second condition described above will also be referred to as the "second standard plasma test" below. In the second standard plasma test, as described above, the bias output was turned OFF, so the plasma was not drawn towards the protective film 200 and was hardly used for etching the protective film 200. The surface 210 of the protective film 200 is simply exposed to a non-directional plasma.

[0023] Figure 2 shows the results of the first standard plasma test performed on each of the multiple structural members 10. The horizontal axis of the graph in Figure 2 represents the indentation hardness of the surface 210 of each sample in units of "GPa". The method for measuring indentation hardness is as described above.

[0024] The vertical axis of the graph in Figure 2 represents the etching rate in the first standard plasma test, i.e., the depth to which the protective film 200 is etched per unit time, expressed in units of "μm / h". The higher the durability of the protective film 200 against the plasma, the lower its etching rate. The etching rate can be used as one indicator of the durability of the protective film 200 against the plasma.

[0025] Figure 2 shows the etching rate values, along with the error range, measured after the first standard plasma test for five structural member 10 samples that differ in the indentation hardness of the protective film 200.

[0026] As is clear from Figure 2, the higher the indentation hardness value of the protective film 200, the lower the etching rate of the protective film 200. For protective films 200 to the right of the dotted line shown in Figure 2, i.e., those with an indentation hardness greater than 7.2 GPa, the etching rate is sufficiently low, confirming that they have sufficient durability against plasma.

[0027] If the indentation hardness of the protective film 200 is set to 7.5 GPa or higher, more preferably 8.0 GPa or higher, the etching rate will be further reduced. Furthermore, according to experiments conducted separately by the inventors, it has been confirmed that if the indentation hardness of the protective film 200 is set to 14.0 GPa or higher, the etching rate will be even lower than the above, and the durability of the protective film 200 against plasma will be further enhanced.

[0028] Figure 3 shows the results of the second standard plasma test performed on each of the multiple structural members 10. The horizontal axis of the graph in Figure 3, like the horizontal axis in Figure 2, represents the indentation hardness of the surface 210 of each sample in units of "GPa". The samples prepared for the second standard plasma test were prepared using the same method as the samples prepared for the first standard plasma test. Therefore, the indentation hardness values ​​of each sample shown in Figure 3 are the same as the indentation hardness values ​​of each sample shown in Figure 2.

[0029] The vertical axis of the graph in Figure 3 represents the fluorination amount of protective film 200 after the second standard plasma test. "Fluorination amount" is an indicator of how much fluorine atoms, which are part of the plasma, have penetrated into the protective film 200. The specific method for calculating the fluorination amount is as follows.

[0030] First, the surface 210 of the protective film 200, which had undergone the second standard plasma test, was sputtered with argon, and the amount of fluorine atoms present on the surface 210 was continuously measured using X-ray photoelectron spectroscopy (XPS). The measurement was performed over 145 seconds. At each time point, the percentage (in units: %) of the argon measurement was calculated, and the cumulative value of the obtained values ​​was calculated as the "fluorination amount" of the sample. The higher the durability of the protective film 200 against plasma, the smaller the fluorination amount calculated as described above. The fluorination amount, like the etching rate mentioned earlier, can be used as one of the indicators of the durability of the protective film 200 against plasma.

[0031] As is clear from Figure 3, the higher the indentation hardness value of the protective film 200, the lower the amount of fluoride in the protective film 200. For the protective film 200 to the right of the dotted line shown in Figure 3, i.e., with an indentation hardness greater than 7.2 GPa, the amount of fluoride is sufficiently low, and it was confirmed that it has sufficient durability against plasma.

[0032] If the indentation hardness of the protective film 200 is set to 7.5 GPa or higher, more preferably 8.0 GPa or higher, the amount of fluoride will be further reduced. Furthermore, according to experiments conducted separately by the inventors, it has been confirmed that if the indentation hardness of the protective film 200 is set to 14.0 GPa or higher, the amount of fluoride will be even lower than the above, and the durability of the protective film 200 against plasma will be further enhanced.

[0033] The manufacturing methods for each sample used in the above measurements will be explained with reference to Figure 4. The sample shown as "No. 1" in the figure is a sample prepared under conditions that result in an indentation hardness of 4.6 GPa for the protective film 200. "No. 2" is a sample prepared under conditions that result in an indentation hardness of 6.2 GPa for the protective film 200. "No. 3" is a sample prepared under conditions that result in an indentation hardness of 7.2 GPa for the protective film 200. "No. 4" is a sample prepared under conditions that result in an indentation hardness of 8.3 GPa for the protective film 200. "No. 5" is a sample prepared under conditions that result in an indentation hardness of 9.0 GPa for the protective film 200.

[0034] The protective films 200 for samples No. 1 to 5 were all deposited using the aerosol deposition method. As is well known, in the aerosol deposition method, fine particles, 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 onto the surface 110 and collided with it. On the surface 110, the impact of the collision causes deformation and fragmentation of the fine particles, and as the fine particles bond together, they gradually accumulate to form the protective film 200. Figure 4 shows the type of "gas" used during the deposition of each sample, and the flow rate at which the gas was sprayed from the nozzle.

[0035] As the "fine particles" mentioned above, La2Zr2O7 powder was used. The average particle size of this powder was 2.3 μm, and the median diameter was 2.1 μm.

[0036] As shown in Figure 4, each of the samples from No. 1 to 5 differs from the others in terms of the deposition conditions for the protective film 200 (specifically, the type and flow rate of the gas), and as a result, the indentation hardness of the protective film 200 also differs from one another.

[0037] One pair of samples No. 1 through 5 were prepared. One sample underwent the first standard plasma test, yielding the results shown in Figure 2. The other sample underwent the second standard plasma test, yielding the results shown in Figure 3.

[0038] The inventors measured the arithmetic mean height (Sa) of surface 210 for each sample from No. 1 to 5 before and after performing the first standard plasma test. In the table in Figure 4, the "Before Etching" column shows the arithmetic mean height of surface 210 measured before the first standard plasma test, in units of μm. The "After Etching" column shows the arithmetic mean height of surface 210 measured after the first standard plasma test, in units of μm. The "ΔSa" column shows the difference between the two arithmetic mean heights. That is, it shows the change in the arithmetic mean height of surface 210 due to the first standard plasma test, in units of μm. The method for measuring the arithmetic mean height was the method specified in ISO 25178.

[0039] In samples No. 1 to 3, i.e., each sample in which the indentation hardness of the protective film 200 is 7.2 GPa or less, the arithmetic mean height of the surface 210 of the protective film 200 after the first standard plasma test is all greater than 0.05 μm. On the other hand, in samples No. 4 to 5, i.e., each sample in which the indentation hardness of the protective film 200 is greater than 7.2 GPa, the arithmetic mean height of the surface 210 of the protective film 200 after the first standard plasma test is all less than 0.05 μm.

[0040] The inventors observed the surface 210 of each sample No. 1 to 5 using a scanning electron microscope (SEM) before and after performing the first standard plasma test. Figure 5 shows the images obtained from this observation. Each image is a so-called "secondary electron image" and was taken under an accelerating voltage of 3 kV. The magnification of the image was 5000x. The "Before Etching" column in Figure 5 shows the image obtained from observation before the first standard plasma test. The "After Etching" column shows the image obtained from observation after the first standard plasma test.

[0041] The inventors also measured the porosity of the protective film 200. Here, "porosity" refers to the percentage of the cross-section of the protective film 200 when it is cut along a plane perpendicular to the surface 210, where the cross-section is occupied by voids.

[0042] The method for measuring the porosity is as follows. First, the above cross-section was observed using a scanning electron microscope (SEM) and a secondary electron image was obtained. The acceleration voltage was set to 3kV and the magnification was set to 30,000x. Figure 6(A) shows an example of an image obtained using the above procedure. The sample used for measurement is sample No. 4 in the table in Figure 4.

[0043] Next, the porosity of the protective film 200 was calculated by analyzing the images obtained as described above. The image analysis was performed using the OpenCV module for the Python language. First, the captured images were cropped to include only the cross-section of the protective film 200. Specifically, the part of the image in Figure 6(A) outside the dotted line DL was cropped and excluded.

[0044] Figure 6(B) shows the image after the above cropping process has been performed. The entire image is a cross-section of the protective film 200. The multiple black dots visible in the image of Figure 6(B) (one of which is indicated by arrow AR) are cross-sections of voids contained in the protective film 200.

[0045] After cropping, the image in Figure 6(B) was binarized so that the cross-sections of the voids were black and the other cross-sections were white. The binarization was performed using the "Variable Threshold Binarization Method" described in the Journal of the Institute of Image Electronics Engineers of Japan, Vol. 36 (2007), No. 3 (pp. 204-209). Subsequently, noisy areas were removed by dilation processing, etc., to obtain the binary image shown in Figure 6(C). In this figure, the black dots labeled "250" correspond to the cross-sections of the voids contained in the protective film 200.

[0046] The ratio of black pixels to the total number of pixels in the image in Figure 6(C) was calculated as the porosity of the protective film 200. In the example shown in Figure 6(C), the total number of pixels in the image was 947,200, and the number of black pixels was 981. Therefore, the porosity was calculated to be approximately 0.10%. The inventors have confirmed that if the indentation hardness of the protective film 200 is greater than 7.2 GPa and the porosity of the protective film 200 is 0.15% or less, the durability of the protective film 200 against plasma will be further increased.

[0047] Furthermore, the inventors have confirmed that forming the protective film 200 such that the average crystallite size is 50 nm or less further increases the durability of the protective film 200 against plasma. "Average crystallite size" refers to a value obtained, for example, by performing a circular approximation on each of the multiple (at least 15) crystallites appearing on the surface 210 of the protective film 200 and taking the average value of the diameter of each circle. To calculate the average crystallite size of the protective film 200, the surface 210 of the protective film 200 is photographed using a transmission electron microscope (TEM), and the average crystallite size is calculated based on the obtained image. In this case, it is preferable to use a magnification of 400,000 times or more.

[0048] The table in Figure 4 shows the average crystallite size values ​​of the protective film 200 calculated as described above for each of the samples from No. 1 to 5. For each sample, it was confirmed that the average crystallite size of the protective film 200 was 50 nm or less. The durability of the protective film 200 can be further improved by making the average crystallite size of the protective film 200 more preferably 30 nm or less, and even more preferably 15 nm or less.

[0049] The higher the indentation hardness of the protective film 200, the more likely it is that densification will occur due to fracture deformation during film formation. Therefore, the higher the indentation hardness of the protective film 200, the smaller the average crystallite size of the protective film 200 tends to be.

[0050] Incidentally, in semiconductor manufacturing equipment, wet etching using acidic aqueous solutions such as hydrochloric acid is sometimes performed on the substrate to be processed for cleaning purposes. During wet etching, not only the substrate but also the surface of the protective film 200 is exposed to the acidic aqueous solution, so there is a possibility that the shape of the surface may change due to the effects of the acidic aqueous solution. Such changes in surface shape are undesirable in order for the protective film 200 to function properly over a long period of time. Therefore, the protective film 200 is required to have durability against corrosion by acidic aqueous solutions in addition to durability against plasma.

[0051] Experiments conducted by the inventors have shown that reducing the average crystallite size of the protective film 200 improves its resistance to plasma, as mentioned earlier, but decreases its resistance to acidic aqueous solutions.

[0052] To clarify the relationship between the average crystallite size of the protective film 200 and its durability against acidic aqueous solutions, the inventors conducted additional experiments using hydrochloric acid aqueous solution, one of the acidic aqueous solutions used for wet etching, as described below. Figure 7 shows the parameters, such as manufacturing conditions, for each of the five samples prepared for the experiment.

[0053] Each of the samples No. 5 to 9 shown in Figure 7 is a sample in which a protective film 200 was deposited on the surface 100 of a substrate 100 using the aerosol deposition method, similar to the samples in Figure 4. La2Zr2O7 powder was used as the fine particles ejected from the nozzle during film deposition. The average particle size of this powder was 2.3 μm, and the median diameter was 2.1 μm. Note that the sample labeled "No. 5" in Figure 7 was manufactured under the same conditions as the "No. 5" sample described earlier with reference to Figure 4.

[0054] Similar to Figure 4, Figure 7 also shows the type of gas used during film deposition for each sample, and the flow rate at which that gas was injected from the nozzle.

[0055] After the formation of protective film 200 was complete, samples No. 6 to 9 were subjected to heat (annealing) treatment before measuring their induction tension hardness and crystallite size. Sample No. 5, however, was not subjected to heat treatment.

[0056] During the heat treatment, each sample was heated at a heating rate of 50°C / h until the temperature of the protective film 200 reached the temperatures shown in the "Annealing Temperature" column of Figure 7. Once the heating was complete, the temperature of the protective film 200 was kept constant for 240 minutes, and then the temperature of the protective film 200 was lowered at a cooling rate of 50°C / h.

[0057] For samples No. 6 to 9, the indentation hardness and crystallite size of the protective film 200 were measured after each sample had returned to room temperature following the heat treatment. For sample No. 5, the indentation hardness and crystallite size of the protective film 200 were measured after the film deposition was completed, without further heat treatment. The "Hardness" and "Crystallite Size" columns in Figure 7 show the measured values ​​for the indentation hardness and crystallite size of each sample, respectively.

[0058] As shown in Figure 7, it was observed that the higher the temperature of the protective film 200 during the heat treatment, the higher the indentation hardness of the protective film 200 and the larger the crystallite size of the protective film 200 tended to be. By appropriately selecting the heat treatment conditions, the indentation hardness and crystallite size of the protective film 200 can be kept within a predetermined range.

[0059] After measuring the indentation hardness and crystallite size of the protective film 200, the inventors immersed each of the samples No. 5 to 9 in an aqueous hydrochloric acid solution and observed how the surface roughness of the protective film 200 changed. In Figure 7, the "Before Immersion" column shows the arithmetic mean height (Sa) of the surface 210 of the protective film 200 measured before immersion in the aqueous hydrochloric acid solution, in units of "μm". In the "After Immersion" column, the arithmetic mean height (Sa) of the surface 210 measured after immersion in the aqueous hydrochloric acid solution for 60 minutes, in units of "μm". The "ΔSa" column shows the difference between the two arithmetic mean heights. That is, the amount of change in the arithmetic mean height of the surface 210 due to immersion in the aqueous hydrochloric acid solution is shown in units of "μm". The hydrochloric acid concentration of the aqueous hydrochloric acid solution was 6.2%, and the temperature of the aqueous hydrochloric acid solution was 25°C. The method for measuring the arithmetic mean height was the method specified in ISO 25178.

[0060] The arithmetic mean height of surface 210 was measured not only 60 minutes after the start of immersion in the hydrochloric acid solution, but also at 1 minute, 5 minutes, 15 minutes, and 30 minutes after the start of immersion. Figure 8 shows the arithmetic mean height values ​​of surface 210 measured at each of the above time points for each sample from No. 5 to 9. The horizontal axis of the figure, "Immersion Time," represents the elapsed time in minutes from the start of immersion of the protective film 200 in the hydrochloric acid solution.

[0061] As shown in Figures 7 and 8, it was confirmed that the higher the temperature of the preheating treatment performed on each sample, the larger the crystallite size of the protective film 200, and the smaller the change in the shape of the surface 210 (i.e., ΔS) when immersed in hydrochloric acid aqueous solution. In other words, it was confirmed that the larger the crystallite size of the protective film 200 is made by the heat treatment, the higher the durability of the protective film 200 against hydrochloric acid. It was also confirmed that in order to ensure sufficient durability against wet etching performed in semiconductor manufacturing equipment, it is necessary to set the crystallite size of the protective film 200 to 12 nm or larger, as in the samples excluding No. 5. Furthermore, when the inventors prepared several other samples and conducted the same experiment as above, it was confirmed that the smaller the crystallite size of the protective film 200, the greater the variation in the change in surface roughness when immersed in hydrochloric acid aqueous solution.

[0062] As mentioned earlier, in order to ensure sufficient durability of the protective film 200 against plasma, it is preferable to keep the crystallite size of the protective film 200 to 50 nm or less. Therefore, it is preferable that the crystallite size of the protective film 200 be between 12 nm and 50 nm. The temperature and heating rate of the heat treatment should be such that the crystallite size of the protective film 200 falls within the above range, and conditions should be such that damage to the protective film 200 due to thermal stress is unlikely to occur. In the case where the thickness of the protective film 200 is 15 μm, as in this embodiment, it is preferable to keep the heat treatment temperature in the range of, for example, 200°C to 300°C.

[0063] The embodiments have been described above with reference to specific examples. However, this disclosure is not limited to these specific examples. Modifications made to these specific examples by those skilled in the art are also included within the scope of this disclosure, as long as they retain the features of this disclosure. The elements, their arrangement, conditions, shapes, etc., of each of the aforementioned specific examples are not limited to those illustrated and can be modified as appropriate. The elements of each of the aforementioned specific examples can be combined in different ways as appropriate, as long as no technical inconsistencies arise. [Explanation of symbols]

[0064] 10: Structural members 100: Base material 110: Surface 200: Protective film

Claims

1. Substrate and The substrate comprises a protective film covering the surface of the substrate, The protective film contains lanthanum zirconate oxide as its main component, A structural member characterized in that the indentation hardness of the protective film is greater than 7.2 GPa.

2. The structural member according to claim 1, characterized in that the protective film is a film formed using the aerosol deposition method.

3. The lanthanum zirconoxide is La ２ Zr ２ O ７ The structural member according to claim 1, characterized in that it is the same as the structural member according to claim 1.

4. The structural member according to claim 1, characterized in that the indentation hardness of the protective film is 7.5 GPa or more.

5. The structural member according to claim 1, characterized in that the indentation hardness of the protective film is 8.0 GPa or more.

6. The structural member according to claim 1, characterized in that the indentation hardness of the protective film is 14.0 GPa or more.

7. The structural member according to claim 1, characterized in that the average crystallite size of the protective film is 50 nm or less.

8. The structural member according to claim 7, characterized in that the average crystallite size of the protective film is 12 nm or more.

9. The structural member according to claim 1, characterized in that the thickness of the protective film is 15 μm or less.

10. The structural member according to claim 1, characterized in that the arithmetic mean height of the surface of the protective film after the first standard plasma test is less than 0.05 μm.

11. The structural member according to claim 1, characterized in that the porosity of the protective film is 0.15% or less.

12. The structural member according to claim 1, characterized in that it is configured as a component for semiconductor manufacturing equipment.

Images