Composite structure and method for evaluating the same, semiconductor and display manufacturing apparatus

Abstract

Provided is a ceramic coating excellent in particle resistance and a method for evaluating the particle resistance of a ceramic coating. Specifically, it is a composite structure body including a base material and a structure body provided on the base material and having a surface, the structure body including a polycrystalline ceramic, and the composite structure body in which the brightness Sa calculated by TEM image analysis satisfies a prescribed value can be appropriately used as an internal member of a semiconductor manufacturing device that requires particle resistance.

Description

[0001] This application is a divisional application of patent application No. 201910171153.5, filed on March 7, 2019, entitled "Composite Structure and Evaluation Method Thereof, Semiconductor and Display Manufacturing Apparatus". Technical Field

[0002] This invention relates to a composite structure in which a polycrystalline ceramic is coated onto the surface of a substrate material to give the substrate material functionality. Furthermore, this invention relates to a semiconductor manufacturing apparatus and a display manufacturing apparatus equipped with this composite structure. In particular, this invention relates to a composite structure with excellent particle resistance for use in environments where semiconductor manufacturing apparatus components, etc., are exposed to corrosive plasma, a method for evaluating the composite structure, and a semiconductor manufacturing apparatus and a display manufacturing apparatus equipped with the composite structure. Background Technology

[0003] It is well known that ceramic coatings are used to imbue substrate materials with functionality. Examples of such ceramic coatings include anti-plasma coatings for cavity components in semiconductor manufacturing devices, insulating coatings for heat dissipation substrates, ultra-smooth coatings for optical mirrors, and scratch-resistant and wear-resistant coatings for sliding components. As the functionality of such components increases, the requirements for their performance become more stringent. In these ceramic coatings, the performance is determined not only by their material composition but also, and potentially more importantly, by their physical structure, especially their microstructure.

[0004] Various ceramic coating technologies have been developed as methods to obtain such ceramic coatings, including aerosol deposition method (AD method), physical vapor deposition (PVD) method for thick film formation by plasma or ion assistance (Plasma-Enhanced Physical Vapor Deposition (PEPVD) method), ion beam assisted deposition (IAD) method, and suspension spraying method using micro-material suspension.

[0005] The ceramic coatings carefully manufactured using these methods also allow for some control over their microstructure. In the reports up to this point, the porosity confirmed by image analysis methods such as SEM (Scanning Electron Microscope) is 0.01–0.1%.

[0006] For example, Japanese Patent Application Publication No. 2005-217351 (Patent Document 1) discloses a layered structure composed of yttrium oxide polycrystalline material with a porosity of 0.05 area% or less as a component for a semiconductor manufacturing apparatus with plasma resistance. This layered structure has appropriate plasma resistance.

[0007] Furthermore, Korean Patent Publication 20170077830A (Patent Document 2) discloses a YF3 transparent fluorine film with high resistance to plasma and corrosive gases. Because this YF3 film is a relatively dense film with a porosity of 0.01-0.1%, it exhibits high resistance to plasma and the like. Additionally, it has a voltage withstand capability of 50-150V / μm.

[0008] Japanese Patent Publication No. 2016-511796 (Patent Document 3) discloses a ceramic coating of Y₂O₃ or similar materials containing constituent particles with a particle size ranging from 200 to 900 nm and constituent particles with a particle size ranging from 900 nm to 10 μm. This coating is relatively dense with a porosity of 0.01-0.1%, exhibiting high resistance to plasma and the like. Furthermore, it has a voltage withstand capability of 80-120 V / μm.

[0009] The refractive index and reflectance of yttrium oxide sintered body, as a transparent plate-shaped sample, were disclosed in the Journal of the Japanese Chemical Society 1979, (8), pp. 1106-1108 (Non-Patent Document 1). (See reference) Figure 10 ).

[0010] In the field of semiconductor manufacturing equipment, the miniaturization of semiconductor devices is advancing every year. If extreme ultraviolet lithography (EUV) becomes practical, it is estimated that it could reach several nanometers. According to the International Roadmap for Devices and Systems (IRDS) produced by the Institute of Electrical and Electronics Engineers (IEEE) and the 2016 version of Moore's White Paper, it is predicted that although the lateral half-pitch between devices will be 18.0 nm in 2017, it will decrease to below 12.0 nm in 2019, and further decrease to below 10.0 nm after 2021.

[0011] Further advancements will be made in reducing circuit linewidth and miniaturizing circuit spacing to achieve high integration of such semiconductors. Additionally, corrosive plasmas such as fluorine-based plasmas (CF4, NF3, etc.) and chloride-based plasmas will be used in etching processes. Furthermore, future processes will utilize even higher-density plasmas, requiring higher levels of particle resistance (low dust generation) for various components within semiconductor manufacturing equipment.

[0012] Previously, it was believed that the plasma resistance of ceramic coatings was related to their porosity. It was thought that suppressing the consumption of the ceramic coating due to plasma corrosion would suppress particle generation. Based on this understanding, the porosity of structures was made as small as 0.01% to 0.1%, thus solving the particle generation problem. However, according to the inventors' knowledge, even structures with very low porosity cannot solve the problem of suppressing particle generation in the process of further miniaturization. That is, it has been recognized that not only must the consumption of the ceramic coating, as indicated by porosity, be suppressed, but particle generation must also be suppressed with greater precision from different perspectives.

[0013] In other words, in recent years, with the miniaturization of devices and the high density of plasma, even ceramic structures with a porosity of 0.01 to 0.1% that contain almost no pores still present the problem of particle generation, requiring structures with higher particle resistance. Furthermore, even in future semiconductor circuits with linewidths on the order of several nm, ceramic structures that can solve the particle problem are required.

[0014] Patent documents

[0015] Patent Document 1: Japanese Patent Application Publication No. 2005-217351

[0016] Patent Document 2: Korean Patent 20170077830A

[0017] Patent Document 3: Japanese Patent Publication No. 2016-511796

[0018] Non-patent literature

[0019] Non-patent literature 1: Journal of the Chemical Society of Japan, 1979, (8), pp. 1106-1108, “Refractive index and reflectivity of yttrium oxide sintered bodies” Summary of the Invention

[0020] The inventors have successfully obtained composite structures that, for example, minimize the impact of particles in ceramic coatings used in semiconductor manufacturing equipment exposed to corrosive plasma environments. Furthermore, they discovered that several indicators exhibit a very high correlation with particle resistance, and based on this, they successfully created structures with excellent particle resistance as specified by these indicators, specifically those involved in the first to fifth aspects described later.

[0021] Therefore, the technical problem to be solved by the present invention is to provide a composite structure with a polycrystalline ceramic structure in which the microstructure is controlled, and in particular, to provide a composite structure having a polycrystalline ceramic structure on a matrix material, which can solve the problem of suppressing particle generation even in highly miniaturized and high-density plasma.

[0022] In addition, the technical problem to be solved by the present invention is to provide a semiconductor manufacturing apparatus and a display manufacturing apparatus having the composite structure. Attached Figure Description

[0023] Figure 1 This is a cross-sectional schematic diagram of the composite structure 100 involved in the present invention.

[0024] Figure 2 This is a flowchart illustrating the method for evaluating luminance Sa involved in this invention.

[0025] Figure 3 is a schematic diagram of TEM observation of sample 90.

[0026] Figure 4 It is a schematic diagram representing the TEM image G of structure 10.

[0027] Figure 5 It is a graph representing the TEM image G and the brightness value of each pixel.

[0028] Figure 6 This is a diagram representing the brightness correction of the TEM image G.

[0029] Figure 7 is a graph showing the luminance values ​​in the luminance acquisition area R.

[0030] Figure 8 This is a schematic diagram illustrating an example of using the composite structure 100 as a component 301 of a semiconductor manufacturing apparatus.

[0031] Figure 9 This is a schematic diagram illustrating an example of using the composite structure 100 as a component 302 of a semiconductor manufacturing apparatus.

[0032] Figure 10 This is a schematic diagram illustrating an example of the configuration of an apparatus used in aerosol deposition.

[0033] Figure 11 This is a TEM image of structure 10 at 400,000x magnification.

[0034] Figure 12 is a scanning electron microscope (SEM) image of structure 10.

[0035] Figure 13 is a transmission electron microscope (TEM) image G of structure 10.

[0036] Figure 14 is a scanning electron microscope (SEM) image of the surface of structure 10 after the baseline plasma resistance test.

[0037] Figure 15 It is a graph representing the area of ​​corrosion marks on the surface of structure 10 after the baseline plasma resistance test.

[0038] Figure 16 It is a graph showing the relationship between the brightness Sa on the surface 10a of the structure 10 and the area of ​​the corrosion marks.

[0039] Figure 17 It is a graph showing the relationship between the amount of hydrogen on the surface 10a of the structure 10 and the area of ​​the corrosion marks.

[0040] Figure 18 It is a patterned cross-sectional view used to illustrate the microstructure of composite structures.

[0041] Figure 19 It is a graph showing the relationship between the wavelength and refractive index of structure 10.

[0042] Figure 20 It is a graph showing the wavelength dispersion of the refractive index of yttrium oxide sintered bodies involved in the prior art.

[0043] Symbol Explanation

[0044] 100-Composite structure; 10-Structure; 10a-Structure surface; 10u-Upper region; 10b-Lower region; 11-Air supply unit; 12-Piping; 13-Atomizer supply unit; 14-Cavity; 15-Nozzle; 16-Platform; 17-Drive unit; 18-Exhaust unit; 19-Device; 50-Carbon layer; 60-Tungsten layer; 70-Base material; 70a-Base material surface; dL-Longitudinal length of region; dW-Lateral length of region; R-Brightness acquisition area; G-Image area; Gl- Image longitudinal length; Gw - Image transverse length; L - Longitudinal; W - Transverse; 90 - TEM observation sample; 90h - Sample height; 90u - Upper sample thickness; 90b - Lower sample thickness; 90w - Sample width; 301 - Semiconductor manufacturing apparatus component; 302 - Semiconductor manufacturing apparatus component; 30a - Plasma irradiation area; 30b - Plasma non-irradiation area; 40 - Sampling location for brightness Sa measurement; 31 - Hole; 81 - Primary particle; 82 - Secondary particle; 10c - Microcrystal. Detailed Implementation

[0045] Composite structures

[0046] use Figure 1 The basic structure of the composite structure involved in this invention will be described. Figure 1 This is a cross-sectional schematic diagram of the composite structure 100 according to the present invention. The structure 10 is disposed on the surface 70a of the base material 70. The structure 10 has a surface 10a. This surface 10a is exposed to an environment in which the composite structure requires the physical properties and characteristics imparted by the structure 10. Thus, for example, when the composite structure according to the present invention is a composite structure that possesses particle-resistant physical properties and characteristics through the structure 10, the surface 10 of the composite structure is exposed to corrosive gases such as plasma. In the present invention, the structure 10 comprises polycrystalline ceramic. Furthermore, the structure 10 of the composite structure according to the present invention exhibits predetermined values ​​under the indicators described in the first to fifth embodiments below.

[0047] The composite structure involved in this invention includes a so-called ceramic coating as its structural element 10. By implementing the ceramic coating, the substrate material 70 can acquire various physical properties and characteristics. Furthermore, in this specification, the structural element (ceramic structure) and the ceramic coating are used interchangeably unless specifically defined otherwise.

[0048] According to one embodiment of the invention, structure 10 uses polycrystalline ceramic as its main component. The content of polycrystalline ceramic is 70% or more, preferably 90% or more, more preferably 95% or more. Most preferably, structure 10 is composed of 100% polycrystalline ceramic.

[0049] In addition, according to one embodiment of the present invention, although the structure 10 may also include polycrystalline regions and amorphous regions, it is more preferable that the structure 10 is composed only of polycrystalline regions.

[0050] Methods for determining crystallite size

[0051] As the average crystallite size obtained under the following measurement conditions, the size of the polycrystalline ceramic constituting the structure 10 in this invention is 3 nm or more and 50 nm or less. More preferably, the upper limit is 30 nm, more preferably 20 nm, and even more preferably 15 nm. In addition, the lower limit is preferably 5 nm. The "average crystallite size" in this invention is a value calculated by taking a transmission electron microscope (TEM) image at a magnification of 400,000 times or more and averaging the diameters of 15 approximately circular crystallites in that image. At this time, the sample thickness for the focused ion beam (FIB) processing is made to be sufficiently thin, around 30 nm. As a result, the crystallites can be identified more clearly. The magnification can be appropriately selected in the range of 400,000 times or more. Figure 11 These are examples of TEM images used to determine crystallite size. Specifically, Figure 11 This is a TEM image of structure 10 at 2 millionx magnification. In the image, the region represented by 10c is a microcrystal.

[0052] As described above, the ceramic constituting the structure 10 can be appropriately determined according to the desired physical properties and characteristics of the matrix material 70, and can be a metal oxide, metal fluoride, metal nitride, metal carbide, or a mixture thereof. According to one aspect of the invention, as a compound with excellent anti-particle properties, examples of materials include oxides of rare earth elements, fluorides, fluorine oxides (LnOF), or mixtures thereof. More specifically, examples of the rare earth element Ln include Y, Sc, Yb, Ce, Pr, Eu, La, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu.

[0053] In addition, in the case of insulating structure 10, materials such as Al2O3, ZrO2, AlN, SiC, Si3N4, cordierite, forsterite, mullite, and silica can be used.

[0054] In this invention, the film thickness of structure 10 can be appropriately determined considering the required application, characteristics, film strength, etc. Generally, it is in the range of 0.1 to 50 μm, with an upper limit of, for example, 20 μm, 10 μm, or 5 μm, and can also be less than 1 μm. Here, the film thickness of structure 10 can be confirmed, for example, by cutting structure 10 and observing the cross-section using SEM.

[0055] In this invention, the matrix material 70 is an object that functions through the structure 10, and can be appropriately determined. Examples of its materials include ceramics, metals, and resins, and also composites of these. Examples of composites include composite matrix materials of resin and ceramics, and composite matrix materials of fiber-reinforced plastics and ceramics. Furthermore, its shape is not specifically limited; it can be a flat plate, concave surface, convex surface, etc.

[0056] According to one aspect of the invention, in order to form a good structure 10, the surface 70a of the substrate material 70 bonded to the structure 10 is preferably smooth. According to one aspect of the invention, the surface 70a of the substrate material 70 is subjected to at least one of, for example, sandblasting, physical abrasion, chemical mechanical polishing, buffing, or chemical abrasion to remove irregularities. After such roughness removal, the two-dimensional arithmetic mean roughness Ra of the surface 70a is preferably 0.2 μm or less, more preferably 0.1 μm or less, or the two-dimensional arithmetic mean height Rz is 3 μm or less.

[0057] The composite structure of the present invention can be suitably used as various components within semiconductor manufacturing apparatuses, particularly as components used in environments exposed to corrosive plasma. As mentioned above, particle resistance is required for components within semiconductor manufacturing apparatuses. This is because the composite structure of the present invention, containing polycrystalline ceramics, possesses high particle resistance.

[0058] When the composite structure according to the present invention is used as a component in an environment exposed to corrosive plasma, examples of components constituting the ceramic of the structure 10 include Y2O3, yttrium fluoride oxyfluoride (YOF, Y5O4F7, Y6O5F8, Y7O6F9, and Y... 17 O 14 F 23 ), (YO 0.826 F 0.17 )F 1.174 , YF3, Er2O3, Gd2O3, Nd2O3, Y3Al5O 12 Y4Al2O9, Er3Al5O 12 Gd3Al5O 12 , Er4Al2O9, ErAlO3, Gd4Al2O9, GdAlO3, Nd3Al5O 12 Nd4Al2O9, NdAlO3, etc.

[0059] Anti-plasma

[0060] The composite structure of the present invention, as specified by the indicators in the first to fifth aspects described below, possesses plasma resistance. This plasma resistance can be evaluated using the plasma resistance test described below as a benchmark method. Hereinafter, this plasma resistance test will be referred to as the "benchmark plasma resistance test" in this specification.

[0061] As one embodiment of the present invention, a composite structure having an arithmetic mean height Sa of the surface 10a of the structure 10 after the "benchmark plasma resistance test" of 0.060 or less is preferred, and a composite structure having an arithmetic mean height Sa of 0.030 or less is even more preferred. The arithmetic mean height Sa will be described later.

[0062] As the plasma etching apparatus used for the "benchmark plasma resistance test", an inductively coupled plasma reactive ion etching apparatus (Muc-21 Rv-Aps-Se / Sumitomo Precision Industries) was employed. The plasma etching conditions were as follows: ICP (Inductively Coupled Plasma) output of 1500W as power supply, bias output of 750W, a mixture of 100ccm CHF3 and 10ccm O2 as process gas at a pressure of 0.5Pa, and a plasma etching time of 1 hour.

[0063] The surface 10a of the structure 10 after plasma irradiation was photographed using a laser microscope (e.g., OLS4500 / Olympus). The observation conditions will be described in detail later.

[0064] The arithmetic mean height Sa of the plasma-irradiated surface is calculated from the obtained SEM image. Here, the arithmetic mean height Sa is a roughness parameter that extends the 2D arithmetic mean roughness Ra to 3D, and is a 3D roughness parameter (3D height direction parameter). Specifically, the arithmetic mean height Sa is the height of the area measured by dividing the volume of the portion enclosed by the surface shape curve and the average surface. That is, when the average surface is taken as the xy plane, the longitudinal direction as the z-axis, and the measured surface shape curve as z(x, y), the arithmetic mean height Sa is defined by the following formula.

[0065] Here, “A” in equation (1) represents the measured area.

[0066] Formula 1

[0067]

[0068] Although the arithmetic mean height Sa is a value that is largely independent of the measurement method, it is calculated under the following conditions in the "Benchmark Plasma Resistance Test" section of this manual. The arithmetic mean height Sa is calculated using a laser microscope. Specifically, an "OLS4500 / Olympus" laser microscope is used. An MPLAPON 100xLEXT objective lens (numerical aperture 0.95, working distance 0.35 mm, focal diameter 0.52 μm, measurement area 128 × 128 μm) with a magnification of 100x is used. A λc filter to remove fluctuation components is set to 25 μm. Measurements are taken at three arbitrary locations, and the average value is taken as the arithmetic mean height Sa. In addition, the international standard for three-dimensional surface properties, ISO 25178, is appropriately referenced.

[0069] First aspect of the present invention

[0070] Based on the knowledge that forms the basis of the first aspect of this invention, the inventors have successfully achieved minimal particle influence in composite structures containing polycrystalline ceramics used, for example, in semiconductor manufacturing equipment exposed to corrosive plasma environments. Furthermore, they discovered that by utilizing the amount of hydrogen contained in the structure, measured using Dynamic-Secondary Ion Mass Spectrometry (D-SIMS), as an indicator, it is possible to evaluate particle resistance performance at an extremely high level.

[0071] The composite structure according to the first aspect of the present invention is a composite structure comprising a matrix material and a structure disposed on the matrix material and having a surface. The structure comprises a polycrystalline ceramic, and the number of hydrogen atoms per unit volume at a measurement depth of either 500 nm or 2 μm, as determined by dynamic-secondary ion mass spectrometry (D-SIMS), is 7*10-1. 21 atoms / cm 3 the following.

[0072] Figure 18 It is a patterned cross-sectional view used to illustrate the microstructure of composite structures. Figure 18 In the figures, (a) is the existing composite structure 110, and (b) is the composite structure 100 involved in this invention. In the figures, 80 represents a nanoscale loose structure, and 90 represents a water molecule (OH group). Figure 18 For ease of understanding, although the size of the nanoscale loose structure 80 is represented in a larger way, in reality, the porosity of either of the composite structures 100 and 110 is 0.01 to 0.1% using existing evaluation methods such as SEM.

[0073] The inventors, recognizing that even structures with low porosity (0.01–0.1%) sometimes fail to address particle problems, have successfully developed new structures capable of resolving particle problems at a higher level. The reason existing structures cannot address particle problems is attributed to nanoscale density variations in the microstructure of these structures, resulting in lower plasma resistance compared to denser structures. Furthermore, it is believed that the nanoscale fine porous structure 80 contains, for example, water molecules (OH groups) found in the atmosphere, and their correlation with particle resistance is determined by identifying this amount. In other words, it has been discovered that by determining the hydrogen content of the water molecules (OH groups), a specific new structure capable of resolving particle problems at a higher level can be constructed.

[0074] Specifically, Figure 18 In this study, it was found that the loose structure 80 in the composite structure 100 of the present invention has less than that in the existing composite structure 110, and there are also fewer water molecules (OH groups) present in the loose structure 80. The amount of hydrogen (number of hydrogen atoms per unit volume) in the structure 10 was determined by using the secondary ion mass spectrometry (D-SIMS) method described later, thereby enabling the establishment of a correlation between hydrogen content and antiparticle properties.

[0075] Preparation of the hydrogen content measurement sample in the first embodiment of the present invention

[0076] In the first aspect of the present invention, for example, a sample for hydrogen content determination can be prepared by the following method.

[0077] First, the composite structure having structure 10 can be pre-cut using a die-cutting machine or similar tool. At this time, the structure corresponding to... Figure 8 and Figure 9 The sampling portion 40 is used. While its size can be arbitrary, it is typically made to be 3mm × 3mm to 7mm × 7mm with a thickness of approximately 3mm. Furthermore, the sample thickness can be appropriately determined based on the measuring apparatus used, and can be adjusted by cutting or otherwise modifying the side of the substrate material 70 where the structure 10 is not formed. The arithmetic mean roughness Ra of the two-dimensional surface roughness parameter of the surface 10a of the structure 10 is made to be 0.1μm or less, more preferably 0.01μm, by grinding or the like. The thickness of the structure 10 is made to be at least 500nm, more preferably 1μm or more, and even more preferably 3μm or more.

[0078] In the hydrogen content determination method of this invention, namely the D-SIMS method, a standard sample is typically used for measurement. Preferably, the standard sample is one with the same composition and structure as the sample being measured. For example, at least two samples are prepared, and one of them can be used as the standard sample. The standard sample will be described in detail later.

[0079] The state of the sample before hydrogen content determination is described.

[0080] As previously described, this invention utilizes hydrogen content in a specific method for a loose structure at the nanometer level of structure 100. Therefore, proper management of the sample before hydrogen content measurement, such as placing it in a constant temperature and humidity bath for a specified period, is crucial. Specifically, in this invention, the hydrogen content is measured after the sample has been placed at room temperature (20-25°C), humidity (60% ± 10%), and atmospheric pressure for 24 hours.

[0081] Hydrogen content determination in the first embodiment of the present invention

[0082] Next, the hydrogen content measurement method in the first embodiment of the present invention will be described.

[0083] In this invention, hydrogen content is determined by dynamic-secondary ion mass spectrometry (D-SIMS). For example, the CAMECA-manufactured IMF-7f is used as the apparatus.

[0084] Next, the measurement conditions will be recorded.

[0085] First, conductive platinum (Pt) is vapor-deposited onto the surface of the structure. Cesium (Cs) ions are used as the primary ion species for measurement. The primary accelerating voltage is set to 15.0 kV, and the detection area is set to 8 μm φ. The measurement depth is set to 500 nm and 2 μm.

[0086] Particle resistance largely depends on the properties of the structure surface directly exposed to the plasma environment. Therefore, by determining the hydrogen content in a region at least approximately 500 nm deep from the surface, a correlation between hydrogen content and particle resistance can be effectively established within the structure. On the other hand, when the structure thickness is sufficiently large and the microstructure from the surface to the depth of the measurement object is substantially homogeneous, the reliability of the determination results can be improved by using a region of approximately 2 μm as the measurement object. Furthermore, when the structure 10 has a lower region 10b on the substrate material 70 side and an upper region 10u on the surface 10a side (see reference...), Figure 1 When a multilayer structure is formed with particle resistance, for example, higher in the upper region 10u than in the lower region 10b, it is preferable to set the measurement depth in a manner that allows only the hydrogen content in the upper region 10u to be determined. From this perspective, it is sufficient that the hydrogen content specified in this invention is presented at either a measurement depth of 500 nm or 2 μm. Preferably, the hydrogen content of this invention is satisfied at either a measurement depth of 500 nm or 2 μm.

[0087] In the determination of hydrogen content, prepare the test sample and standard sample.

[0088] To eliminate factors related to measurement conditions, standard samples are typically used in SIMS methods to standardize the signal intensity of the analyte ions using the signal intensity of ions containing the matrix elements of the sample. More specifically, this involves using an evaluation sample and a standard sample with the same matrix composition as the evaluation sample (i.e., a standard sample for the evaluation sample), as well as a Si single crystal and a standard sample for the Si single crystal. The standard sample for the evaluation sample is a sample with the same matrix composition as the evaluation sample, into which deuterium has been injected. Simultaneously, deuterium is also injected into the Si single crystal, assuming that the standard sample for the evaluation sample and the Si single crystal have been injected with equal amounts of deuterium. Then, the standard sample for the Si single crystal is used to make the amount of deuterium injected into the Si single crystal approximately equal. Regarding the standard sample for the evaluation sample, the secondary ion intensities of deuterium and the constituent elements are calculated using secondary ion mass spectrometry (D-SIMS), and the interphase sensitivity coefficient is calculated. The hydrogen content of the evaluation sample is calculated using the interphase sensitivity coefficient calculated from the standard sample for the evaluation sample. For other references, see ISO 18114, "Determination of relative sensitivity from implanted ion standard materials" (International Organization for Standardization, Geneva, 2003).

[0089] In this invention, the number of hydrogen atoms per unit volume contained in the structure constituting the composite structure at a measurement depth of 500 nm or less, as determined by dynamic-secondary ion mass spectrometry (D-SIMS), is 7*10. 21 atoms / cm 3 the following.

[0090] In the structures of this invention, their surfaces are exposed to environments such as plasma. Therefore, the properties of the structure's surface are particularly important. The inventors recognized that even structures with a porosity of only 0.01 to 0.1%, which contain virtually no pores, cannot solve the particle problem due to the influence of nanoscale microstructure. Through research, they successfully controlled this nanoscale microstructure, obtaining a new structure capable of solving the particle problem at a higher level. Furthermore, they discovered that the composition of this new structure can be specified using the surface hydrogen content (the number of hydrogen atoms per unit volume) as an indicator. Moreover, they discovered a correlation between the hydrogen content of the structure's surface and its anti-particle properties, thus completing this invention.

[0091] Specifically, in the atmosphere, hydrogen atoms are considered to exist, for example, as hydroxyl radicals (-OH). The molecular size is approximately 3 Å for water molecules and 1 Å for hydroxyl radicals, and they are considered to be slightly present in the aforementioned loose structure 80 of the structure. By using this amount of hydrogen as an indicator, nanoscale microstructures can be represented.

[0092] In this invention, the hydrogen content of the structure, as determined by D-SIMS, is 7*10^6 hydrogen atoms per unit volume at a measurement depth of either 500 nm or 2 μm. 21 atoms / cm 3 The preferred number of hydrogen atoms per unit volume is 5*10. 21 atoms / cm 3 the following.

[0093] Furthermore, although it is believed that the lower the amount of hydrogen in the structure of the composite structure involved in this invention, the better, those skilled in the art will obviously know that there is a measurement limit. Therefore, the lower limit of the hydrogen content in this embodiment is taken as the measurement limit. This point is also the same in the second embodiment below.

[0094] Second aspect of the present invention

[0095] Although the second embodiment of the present invention also uses hydrogen content as an indicator, similar to the first embodiment, it uses hydrogen content measured by hydrogen forward scattering analysis (HFS)-Rutherford backscattering spectrophotometry (RBS) (RBS-HFS method) and proton-hydrogen forward scattering analysis (p-RBS method) as the indicator. That is, the inventors have successfully achieved minimal particle influence in composite structures containing Y (yttrium) and O (oxygen) used, for example, in semiconductor manufacturing equipment exposed to corrosive plasma environments. Furthermore, it has been discovered that by using the hydrogen content contained in the structure measured by hydrogen forward scattering analysis (HFS)-Rutherford backscattering spectrophotometry (RBS) (RBS-HFS method) and proton-hydrogen forward scattering analysis (p-RBS method) as the indicator, it is possible to evaluate anti-particle performance at an extremely high level.

[0096] The composite structure according to the second aspect of the present invention is a composite structure comprising a matrix material and a structure disposed on the matrix material and having a surface, the structure comprising a polycrystalline ceramic, wherein the hydrogen atom concentration determined by hydrogen forward scattering analysis (HFS)-Rutherford backscattering spectrophotometry (RBS) (RBS-HFS method) and proton-hydrogen forward scattering analysis (p-RBS method) is less than 7 atomic%.

[0097] The second aspect of the present invention differs from the first aspect of the present invention in the method for determining the amount of hydrogen. Except for the addition of changes due to this, the description of the first aspect in this specification becomes the description of the second invention.

[0098] Preparation of the hydrogen content measurement sample in the second embodiment of the present invention

[0099] In the second aspect of the present invention, for example, a sample for hydrogen content determination can be prepared by the following method.

[0100] First, a composite structure having structure 10 is pre-cut using a die-cutting machine or similar tool. At this time, the structure corresponding to... Figure 8 and Figure 9 The sampling portion 40 is used. While its size can be arbitrary, it is typically made to be approximately 20mm x 20mm with a thickness of about 5mm. The thickness of the sample can be appropriately determined based on the measuring apparatus used, and is adjusted by cutting or otherwise modifying the side of the substrate material 70 where the structure 10 is not formed. The arithmetic mean roughness Ra of the two-dimensional surface roughness parameter of the surface 10a of the structure 10 is made to be 0.1μm or less, more preferably 0.01μm, by grinding or the like. The thickness of the structure 10 is made to be at least 500nm, more preferably 1μm or more, and even more preferably 3μm or more.

[0101] The state of the sample before hydrogen content determination is described.

[0102] As previously described, this invention utilizes hydrogen content in a specific method for a loose structure at the nanometer level of structure 100. Therefore, proper management of the sample before hydrogen content measurement, such as placing it in a constant temperature and humidity bath for a specified period, is crucial. Specifically, in this invention, the hydrogen content is measured after the sample has been placed at room temperature (20-25°C), humidity (60% ± 10%), and atmospheric pressure for 24 hours.

[0103] Hydrogen content determination in the second embodiment of the present invention

[0104] Next, the method for determining hydrogen content will be explained.

[0105] In this invention, hydrogen content determination combines Hydrogen Forward Scattering Spectrometry (HFS) / Rutherford Backscattering Spectrometry (RBS) (hereinafter referred to as RBS-HFS) and Proton-based RBS (hereinafter referred to as p-RBS). The apparatus, for example, can be a Pelletron 3SDH manufactured by National Electrostatics Corporation.

[0106] The method for determining the hydrogen content will be further explained.

[0107] The RBS-HFS method using helium (He) is implemented. The structure is irradiated with helium (He) atoms, and the backscattered He atoms and the forward-scattered H atoms are detected. The energy spectrum of the backscattered He atoms is fitted sequentially from the element with the highest energy spectrum to calculate the scattering intensity. Similarly, the energy spectrum of the forward-scattered H atoms is also fitted to calculate the scattering intensity. Based on each calculated scattering intensity, the ratio of the average number of atoms of each element in the structure can be calculated. For example, when the structure is yttrium oxide, the scattering intensity is calculated by fitting the energy spectrum of the detected He atoms to the element Y, and then by fitting the energy spectrum of the element O. Furthermore, for the specific element with the highest energy spectrum, it is preferable to combine it with other methods such as energy-dispersive X-ray analysis (EDX).

[0108] Although the average atomic ratio of elements in a structure can be determined using the RBS-HFS method described above, this invention also utilizes protons (H) to improve the accuracy of the determination. + The p-RBS method was used to re-determine the ratio of the average number of atoms other than hydrogen in the structure. In the calculation, the scattering intensity was calculated by fitting the elements with the largest energy spectra in sequence, similar to the RBS-HFS method. Based on each calculated scattering intensity, the ratio of the average number of atoms of the elements in the structure was calculated. Furthermore, by combining the ratio of the average number of atoms determined by the p-RBS method with the ratio of the element with the largest energy spectrum of detected He atoms (e.g., Y when the structure is yttrium oxide) to the average number of hydrogen atoms, the hydrogen content was calculated as the hydrogen atom concentration (atomic %).

[0109] In this invention, the order in which the p-RBS method and the RBS-HFS method are implemented is not specifically limited.

[0110] Next, the measurement conditions will be recorded.

[0111] RBS-HFS method

[0112] Injected ions using 4He + The incident energy was set to 2300 keV, the incident angle to 75°, the scattering angle to 160°, and the reflection angle to 30°. The sample current was set to 2 nA, the beam diameter to 1.5 mmφ, and the irradiation dose to 8 μC. No in-plane rotation was observed.

[0113] p-RBS method

[0114] The injected ions use hydrogen ions (H+). +The incident energy was set to 1740 keV, the incident angle to 0°, the scattering angle to 160°, and there was no reflection angle. The sample current was set to 1 nA, the beam diameter to 3 mmφ, and the irradiation dose to 19 μC. There was no in-plane rotation.

[0115] By combining the p-RBS method with the RBS-HFS method, the accuracy of hydrogen atom concentration determination can be further improved, and the amount of hydrogen (hydrogen atom concentration) can be determined by establishing a correlation between particles.

[0116] The hydrogen atom concentration in the structure constituting the composite structure of the present invention is 7 atomic percent or less. In the structure of the present invention, its surface is exposed to, for example, a plasma environment. Therefore, the properties of the structure's surface are particularly important. The inventors believed that even structures with almost no pores and a porosity of 0.01 to 0.1% could not solve the particle problem due to the influence of the nanoscale microstructure. Through research, they successfully controlled this nanoscale microstructure, obtaining a new structure capable of solving the particle problem at a higher level. Furthermore, they discovered that the composition of this new structure can be specified using the surface hydrogen content (hydrogen atom concentration) as an indicator. Moreover, they discovered the correlation between the hydrogen content on the structure's surface and its anti-particle properties, thus completing the present invention.

[0117] Specifically, in the atmosphere, hydrogen atoms are considered to exist, for example, as hydroxyl radicals (-OH). The molecular size is approximately 3 Å for water molecules and 1 Å for hydroxyl radicals, and they are considered to be slightly present in the aforementioned loose structure 80 of the structure. By using this amount of hydrogen (hydrogen atom concentration) as an indicator, nanoscale microstructures can be represented.

[0118] In this invention, a combination of p-RBS and RBS-HFS methods is used as a specific method for measuring hydrogen content. In these methods, helium ions or hydrogen ions are injected into the sample surface. Due to elastic scattering, hydrogen is scattered forward, and helium is scattered backward. The hydrogen content is determined by detecting this hydrogen. At this time, the hydrogen content is measured at a depth of 400-500 nm from the surface 10a. Thus, in the structure 10, the microstructure of the surface 10a, which most affects the anti-particle structure, can be appropriately quantified.

[0119] The third aspect of the present invention

[0120] As the basis for the third aspect of this invention, a new index called brightness Sa was discovered to have a very high correlation with anti-particle performance. Based on this, a structure with excellent anti-particle performance and a brightness Sa below a specified value was successfully fabricated. That is, a structure with extremely high anti-particle performance was obtained, and it was discovered that this anti-particle performance can be quantified by brightness Sa. Furthermore, a method for evaluating brightness Sa was further established.

[0121] Furthermore, the inventors have discovered that, in ceramic structures, especially those with a porosity of 0.01 to 0.1%, brightness Sa, which is related to particle resistance, is an indicator for evaluating finer structures (microstructures).

[0122] The composite structure according to the third aspect of the present invention is as follows.

[0123] It comprises a matrix material and a structure disposed on the matrix material and having a surface, characterized in that,

[0124] The structure comprises polycrystalline ceramics.

[0125] The luminance Sa value calculated using the following method is below 19.

[0126] The method for obtaining the brightness Sa comprises the following steps:

[0127] That is, (i) the process of preparing the sample for observation by a transmission electron microscope (TEM) of the structure;

[0128] (ii) The process of preparing a digital black-and-white image of the bright-field image of the TEM observation sample;

[0129] (iii) The process of obtaining the brightness value of each pixel in the digital black and white image by representing the color data of each pixel with grayscale values;

[0130] (iv) The process of correcting the brightness value;

[0131] and (v) the process of calculating the luminance Sa using the corrected luminance value.

[0132] In the process (i),

[0133] Prepare at least three TEM observation specimens from the structure.

[0134] At least three TEM observation samples were prepared separately to suppress processing damage using the focused ion beam (FIB) method.

[0135] During the FIB processing, a carbon layer and a tungsten layer are formed on the surface of the structure to prevent charging and protect the sample.

[0136] When the FIB processing direction is taken as the longitudinal direction, the length of the minor axis of the structure surface, i.e., the upper thickness of the sample, is 100±30 nm on a plane perpendicular to the longitudinal direction.

[0137] In process (ii),

[0138] The digital black and white images were obtained for each of the at least three TEM observation samples.

[0139] When using a transmission electron microscope (TEM) at 100,000x magnification and 200kV accelerating voltage, the digital black and white image contains the structure, the carbon layer, and the tungsten layer, respectively.

[0140] In the digital black and white image, a brightness region is defined from the surface of the structure, with a longitudinal length of 0.5 μm.

[0141] Multiple digital black-and-white images were obtained from the at least three TEM observation samples, such that the total area of ​​the brightness acquisition region was 6.9 μm. 2 above,

[0142] In the process (iv),

[0143] Regarding the brightness value, the brightness value of the carbon layer is set to 255, and the brightness value of the tungsten layer is set to 0, and a relative correction is performed to obtain the corrected brightness value.

[0144] In the process (v),

[0145] Regarding the brightness acquisition area, the average of the absolute values ​​of the corrected brightness value differences of each pixel is calculated using the least squares method, and these averages are taken as the brightness Sa.

[0146] Furthermore, the evaluation method involved in the third aspect of the present invention is as follows:

[0147] A method for evaluating the microstructure of structures containing polycrystalline ceramics and having a surface, characterized by the following:

[0148] It consists of the following processes,

[0149] That is, (i) the process of preparing the sample for observation by a transmission electron microscope (TEM) of the structure;

[0150] (ii) The process of preparing a digital black-and-white image of the bright-field image of the TEM observation sample;

[0151] (iii) The process of obtaining the brightness value of each pixel in the digital black and white image by representing the color data of each pixel with grayscale values;

[0152] (iv) The process of correcting the brightness value;

[0153] and (v) the process of calculating the luminance Sa using the corrected luminance value.

[0154] In the process (i),

[0155] Prepare at least three TEM observation specimens from the structure.

[0156] At least three TEM observation samples were prepared separately to suppress processing damage using focused ion beam (FIB) method.

[0157] During the FIB processing, a carbon layer and a tungsten layer are formed on the surface of the structure to prevent charging and protect the sample.

[0158] When the FIB processing direction is taken as the longitudinal direction, the length of the minor axis of the structure surface, i.e., the upper thickness of the sample, is 100±30 nm on a plane perpendicular to the longitudinal direction.

[0159] In process (ii),

[0160] The digital black and white images were obtained for each of the at least three TEM observation samples.

[0161] When using a transmission electron microscope (TEM) at 100,000x magnification and 200kV accelerating voltage, the digital black and white image contains the structure, the carbon layer, and the tungsten layer, respectively.

[0162] In the digital black and white image, a brightness region is defined from the surface of the structure, with a longitudinal length of 0.5 μm.

[0163] Multiple digital black-and-white images were obtained from the at least three TEM observation samples, such that the total area of ​​the brightness acquisition region was 6.9 μm. 2 above,

[0164] In the process (iv),

[0165] Regarding the brightness value, the brightness value of the carbon layer is set to 255, and the brightness value of the tungsten layer is set to 0, and a relative correction is performed to obtain the corrected brightness value.

[0166] In the process (v),

[0167] Regarding the brightness acquisition area, the average of the absolute values ​​of the corrected brightness value differences of each pixel is calculated using the least squares method, and these averages are taken as the brightness Sa.

[0168] Brightness Sa in the third aspect of the present invention

[0169] In the third aspect of the present invention, the microstructure of the structure is represented by an index called "brightness Sa". As detailed below, "brightness Sa" is an index obtained by quantifying the pixel information of a digital black-and-white image of a bright-field image of the structure obtained by transmission electron microscopy (TEM). The composite structure according to the present invention is characterized in that the brightness Sa is 19 or less, preferably 13 or less.

[0170] The inventors have discovered that, in ceramic structures, particularly in structures with a porosity of 0.01 to 0.1%, brightness Sa, which is related to particle resistance, is an indicator for evaluating finer structures. Therefore, in this invention, "microstructure" refers to the fine structure in regions exhibiting a higher level of particle resistance and showing differences in brightness Sa within such structures with a porosity of 0.01 to 0.1%.

[0171] In this manual, "luminance value" refers to the value of the color data of each pixel in a digital black and white image, expressed using grayscale values ​​(0-255). Here, "grayscale" refers to the level of brightness. Specifically, the value of the color data of each pixel in a black and white image, represented by values ​​corresponding to 256 different brightness levels, is called the luminance value (see "Image Processing Apparatus and Method of Using It", Nikkan Kogyo Shimbun, 1989, first edition, page 227). The contrast between black and white in a TEM black and white image is used as the luminance value.

[0172] In this specification, "Brightness Sa" is an image processing metric that applies the concept of Sa (arithmetic mean height of the surface), as defined by the international standard ISO 25178 for three-dimensional surface properties, to digital TEM images. It is represented using 3D. Figure 5 The brightness values ​​of digital TEM images are explained in detail. Figure 5 (a) is a TEM bright-field image, i.e., a digital black-and-white image of the structure. Regarding this digital black-and-white image, the color data of each pixel is represented by grayscale values ​​(0–255), and the graph representing these values ​​along the Z-axis is shown below. Figure 5 (b). That is, Figure 5In (b), the Z-axis represents the luminance value, and the 3D representation is the luminance value of each pixel on the XY plane. The luminance value is determined based on a 3D image of the surface properties specified by ISO 25178 (e.g., refer to the following URL: https: / / www.keyence.co.jp / ss / 3dprofiler / arasa / surface / ). For the evaluation area, the average of the absolute values ​​of the luminance value differences of each pixel is calculated using the least squares method and is taken as the "luminance Sa".

[0173] Next, the "brightness Sa" in this instruction manual is calculated approximately as follows.

[0174] In the calculation of brightness Sa in this invention, a TEM observation sample for obtaining digital black and white images is fabricated using the focused ion beam (FIB) method while suppressing processing damage. During FIB processing, a carbon layer and a tungsten layer are formed on the surface of the structure to prevent charging and protect the sample. When the FIB processing direction is longitudinal, the length of the minor axis of the structure surface, i.e., the thickness of the upper part of the sample, in a plane perpendicular to the longitudinal direction is 100 ± 30 nm. At least three TEM observation samples are prepared from one structure.

[0175] Digital black-and-white images were acquired for at least three TEM-observed samples. The images were obtained using a transmission electron microscope (TEM) at 100,000x magnification and an accelerating voltage of 200 kV. The digital black-and-white images included the structure, carbon layer, and tungsten layer.

[0176] In digital black and white images, a brightness acquisition area is defined as a region with a longitudinal length of 0.5 μm from the surface of the structure along the stated longitudinal direction. Multiple digital black and white images are acquired from at least three TEM observation samples, such that the total area of ​​this brightness acquisition region is 6.9 μm. 2 above.

[0177] Regarding the representation of the brightness value of the color data of each pixel in the acquired digital black and white image using grayscale values, relative correction is performed by using the brightness value of the carbon layer as 255 and the brightness value of the tungsten layer as 0.

[0178] The luminance Sa is calculated using the corrected luminance values ​​as follows: That is, for the luminance acquisition area, the average of the absolute values ​​of the differences in the corrected luminance values ​​of each pixel is calculated using the least squares method, and these averages are taken as the luminance Sa.

[0179] The following is for reference Figures 2-9 The method for calculating the brightness Sa is further described in detail.

[0180] Figure 2 This is a flowchart illustrating the method for calculating luminance Sa. The following explanation follows this flowchart.

[0181] (i): Preparing the TEM observation sample

[0182] This step is the preparation of the sample for TEM observation. This step will be explained with reference to Figure 3. The TEM observation sample is prepared using the focused ion beam method (FIB method). In the FIB method, thin films can be formed on the areas to be observed ("Surface Analysis Technology Series: Transmission Electron Microscopy," edited by the Japanese Society for Surface Chemistry, Maruzen Co., Ltd., published March 30, 2012).

[0183] First, the structure 10 is pre-cut using a die-cutting machine or similar tool. At this point, corresponding to the following... Figure 8 and Figure 9 The sampling portion 40 is first cut out. Then, the surface 10a of the structure is processed using FIB machining to achieve the shape shown in Figure 3. At this point, arrow L in Figure 3 is taken as the longitudinal direction. The longitudinal direction L is approximately parallel to the thickness direction of the structure 10. Furthermore, the longitudinal direction L is approximately the same as the longitudinal direction defined in the aforementioned FIB machining direction.

[0184] The FIB processing will be described in further detail. A carbon layer 50 for suppressing charge and protecting the surface 10a of the structure 10 after die-cutting is deposited by vapor deposition. The deposition thickness of the carbon layer 50 is approximately 300 nm. Here, before forming the carbon layer 50, it is preferable to make the surface 10a of the structure smoother by grinding or the like.

[0185] Next, the structure 10 with the carbon layer 50 deposited is thinned using a focused ion beam (FIB) device. Specifically, the carbon layer 50 is first irradiated with a Ga ion beam around the periphery of the thinned area, and a portion of the structure 10 is cut out along with the carbon layer 50. The cut-out structure 10 is fixed to the FIB TEM stage using a tungsten deposition function via FIB selection. Next, the cut-out structure 10 is thinned to obtain a TEM observation sample 90. The thinning process is as follows: first, a tungsten layer 60 is formed on the carbon layer 50 of the structure 10 at the thinned area for TEM observation by tungsten deposition. By setting the tungsten layer 60, damage to the surface of the TEM observation sample caused by the Ga ion beam can be suppressed during processing. The thickness of the deposited tungsten layer 60 is 500–600 nm. Subsequently, Ga ions were used to cut the structure from both sides of the thinned portion to produce a TEM observation sample 90 with a specified thickness (the length along the arrow T in the figure).

[0186] In this invention, the TEM observation specimen 90 is fabricated in a manner that suppresses processing damage such as unevenness on the machined surface. Specifically, the accelerating voltage during FIB processing starts at the maximum voltage of 40kV, and the final finishing is performed at the minimum voltage of 5kV to minimize damage to the machined surface of the structure and the formation of an amorphous layer. Alternatively, the damaged layer is removed using Ar ions. Observation can also be performed after cleaning the surface by ion milling. For details on these FIB processing methods, please refer to "Micromachining Using FIB Apparatus" (Mitsuhiro Muroi, Technical Report 24: 69-72, University of Tsukuba, 2004) and "FIB / Ion Milling Method Q&A" (Masao Hirasaka and Kentaro Asakura, Agne Jōfūsha).

[0187] Figures 3(a) and 3(b) are schematic diagrams of the TEM observation sample 90 obtained as described above. As shown in Figures 3(a) and (b), the TEM observation sample 90 has a relatively thin cuboid shape. In Figure 3, regarding the two directions perpendicular to the longitudinal direction L, the long axis direction is taken as the transverse direction W (arrow W in the figure), and the short axis direction is taken as the thickness direction T (arrow T in the figure). As shown in Figure 3(a), electron beams pass through the thickness direction T during TEM observation.

[0188] As shown in Figure 3(a), since the thinning process using Ga ions starts from the top of the image, the sample 90 tends to have a larger upper thickness 90u than a lower thickness 90b. Here, the upper thickness 90u is the length of the sample 90 in the thickness direction T on the surface 10a side. TEM observation shows that the thickness of the sample 90 affects the transmittance of electron beams. Specifically, when the sample thickness is too large, the sensitivity of the brightness Sa is less sensitive, and it may be impossible to obtain the correlation with anti-particle performance. When the sample thickness is too small, it is difficult to control the thickness during processing, and thickness deviation occurs within the sample 90 during TEM observation, which may also prevent the obtaining of the correlation with anti-particle performance. In this invention, the upper thickness 90u is 100nm ± 30nm, more preferably 100nm ± 20nm.

[0189] Furthermore, in this invention, since the brightness Sa is calculated by image analysis using a TEM digital black and white image, the sample is processed in a way that minimizes the thickness difference (the difference between the upper thickness 90u and the lower thickness 90b) along the longitudinal direction L of the TEM-observed sample 90. Typically, the sample is processed as shown in Figure 3(a), with a sample height 90h (length of the longitudinal direction L) of approximately 10 μm and a sample width 90w (length of the transverse direction W) of approximately ten μm to several tens of μm.

[0190] The method for confirming the upper thickness 90u of the TEM observation specimen 90 is as follows. For the TEM observation specimen 90, two electron images were obtained using a scanning electron microscope (SEM) (see Figure 3(c)). The upper thickness 90u was obtained from these two electron images. For example, a HITACHI S-5500 SEM was used. The SEM observation conditions were 200,000x magnification, 2kV accelerating voltage, 40-second scan time, and 2560*1920 pixels. The SEM image was then positioned perpendicular to the vertical direction L. The upper thickness 90u was obtained using the scale bar of the SEM image. The upper thickness 90u was then the average of five measurements.

[0191] If an alternative method for confirming the upper thickness 90u is also given, it is as follows: For a digital image of a second electronic image, the brightness value is measured along the thickness direction T to obtain a brightness spectral profile. At this time, the line width is set to 11 pixels, and the average brightness value of the 11 pixel portion along the line width direction is used. An example of such a brightness spectral profile is shown in Figure 3(d). Next, the brightness spectral profile is differentiated once, and the maximum and minimum values ​​of this first differentiation are used as the ends of the structure 10 to obtain the upper thickness 90u of the structure 10 (see Figure 3(e)). At this time, the upper thickness 90u is the average of five brightness spectral profiles.

[0192] In the calculation of the brightness Sa in this invention, at least three of the above-mentioned TEM observation samples 90 are prepared from a composite structure. Regarding the preparation of at least three TEM observation samples, the following is used... Figure 8 and Figure 9 Further explanation is needed.

[0193] Figure 8 and Figure 9 This is a schematic diagram illustrating an example of using the composite structure 100 as a component 301 of a semiconductor manufacturing apparatus. Figure 8 In the semiconductor manufacturing apparatus component 301, a structure 10 is provided on the surface 70a of the cylindrical substrate material 70. Figure 9 In the semiconductor manufacturing apparatus component 302, a structure 10 is provided on the surface 70a of the cylindrical substrate material 70, and a hole 31 is provided in the center of the cylindrical substrate material 70.

[0194] In semiconductor manufacturing apparatus components 301 and 302, the surface 10a of structure 10 is exposed to corrosive plasma. Semiconductor manufacturing apparatus components 301 and 302 are, for example, components that form the inner wall of the etching chamber, such as a cluster plate, focusing ring, fluorescent screen, and observation window. When structure 10 has a plasma-irradiated area 30a and a plasma-non-irradiated area 30b that is not exposed to plasma, a sampling point 40 for measuring brightness Sa is set at a location corresponding to the plasma-irradiated area 30a. In this case, if there is an area particularly irradiated by a large amount of plasma, setting the structure surface 10a corresponding to that area as the sampling point 40 can improve the correlation between particle resistance and brightness Sa.

[0195] In this invention, at least three sampling sites 40 for measuring the brightness Sa are made for preparing the TEM observation sample 90. At this time, as... Figure 8 and Figure 9 As shown, multiple sampling sites 40 are equally distributed within the plasma irradiation region 30a. This ensures a high correlation between the brightness Sa of the composite structure 100 and its particle resistance.

[0196] (ii): Obtain TEM image G (bright field image)

[0197] In this process, at least three TEM observation samples 90 obtained through (i) are observed cross-sections by TEM at a magnification of 100,000x and an accelerating voltage of 200kV, thereby obtaining TEM images G (refer to) containing structure 10, carbon layer 50 and tungsten layer 60. Figure 4 The cross-section of the sample observed by TEM is 90°. Figure 1 The cross-section of the composite structure 100 shown is, more specifically, the cross-section near the surface 10a containing the structure 10. At this time, a bright-field image is obtained. A bright-field image is an image formed by only allowing the transmitted wave to pass through the object's aperture ("Surface Analysis Technology Series: Transmission Electron Microscopy", edited by the Japanese Society for Surface Chemistry, Maruzen Co., Ltd., published on March 30, 2012, pp. 43-44).

[0198] For example, a transmission electron microscope (H-9500 / Hitachi High Technology Co., Ltd.) is used to capture TEM images (G). The accelerating voltage is set to 200kV, and the image is captured using a digital camera (OneView Camera Model 1095 / Gatan) under the same conditions as a 4096×4096 pixel image, 6fps shooting speed, 2sec exposure time, exposure time mode, and a low-position camera. Figure 4As shown, in order to obtain the image G, the structure 10, the structure surface 10a, the carbon layer 50, and the tungsten layer 60 are brought into the same line of sight.

[0199] In this invention, the brightness Sa is calculated through image analysis of the brightness information of the digital image. Therefore, the focusing accuracy during shooting becomes extremely important. Thus, for example, when obtaining a 100,000x TEM image, the 100,000x TEM image is obtained after focusing at a high magnification of 300,000x or more.

[0200] use Figure 4 Further explanation of digital black and white images, i.e., TEM images G. Figure 4 This is a schematic diagram of the TEM image G (bright field image). In the diagram, the quadrilateral part with a vertical length Gl and a horizontal length Gw is the TEM image G. Figure 4 In the TEM image G, there are images corresponding to the carbon layer 50 and tungsten layer 60 deposited in step (i) on the surface 10a of the structure 10. The lower part of the surface 10a corresponds to the structure 10. In addition, in the TEM image G, the carbon layer 50 appears white to light gray, and the tungsten layer 60 appears black.

[0201] Furthermore, in this specification, the orientation of the structure 10, carbon layer 50, and tungsten layer 60 in the TEM image G is... Figure 4 The direction indicated by arrow L in the diagram is called the "vertical direction," and the direction of arrow W, which is perpendicular to the "vertical direction," is called the "horizontal direction." This vertical direction L corresponds to the vertical direction L in Figure 3.

[0202] The physical properties and characteristics of the composite structure involved in this invention, such as anti-particle properties, are governed by the properties near the surface of the structure. The inventors discovered that the brightness Sa in a region with a longitudinal length dL of 0.5 μm along the longitudinal direction L from the surface 10a of the structure is most correlated with physical properties and characteristics such as anti-particle properties. Although the longitudinal length Gl and lateral length Gw of a TEM image obtained at 100,000x magnification vary depending on the camera, they are typically around 1.5 μm to 2.0 μm, respectively. Therefore, in this invention, a TEM image at 100,000x magnification is used, the longitudinal length dL of the region is set to 0.5 μm, and the brightness of the region R is determined. The brightness Sa is then determined from the brightness value in region R.

[0203] In this invention, a brightness acquisition region R is defined for each image G. Furthermore, multiple digital black and white images are acquired from at least three TEM observation samples so that the total area of ​​the brightness acquisition region R is 6.9 μm. 2 That concludes the discussion. At this point, the number of images G obtained from each TEM observation of the sample is the same. The total area of ​​the brightness acquisition region R will be detailed later.

[0204] (iii): Obtain the brightness value

[0205] Next, in this step, for each "vertical" and "horizontal" coordinate in the digital black-and-white image, i.e., the TEM image G, obtained in step (ii), the brightness value of each pixel corresponding to that coordinate is obtained. This also includes the brightness values ​​of the tungsten layer and the carbon layer in image G. Figure 5 (a) is a top view showing an example of a TEM image G obtained. Figure 5 (a) Arrow Y corresponds to Figure 3 and Figure 4 The longitudinal direction L. Figure 5 (a) Arrow X corresponds to Figure 3 and Figure 4 The horizontal W. Figure 5 (b) is a 3D representation of the brightness value of each pixel in the direction of arrow Z in image G.

[0206] (iv): The process of correcting the brightness value

[0207] Next, in this process, the brightness value of the TEM image G obtained in step (iii) is corrected. Using... Figure 6 Please provide an explanation of this specific content. Figure 6 (a) is a graph representing the brightness values ​​of the TEM image G obtained in step (iii) in three dimensions, corresponding to the brightness values ​​of each pixel in the longitudinal and transverse coordinates of the structure 10. Similar to step (iii), this also includes the brightness values ​​of the tungsten layer and the carbon layer in image G. In this step, the brightness value of each pixel is set to 0 for the tungsten layer 60 in image G and 255 for the carbon layer 50 in image G, and a relative correction is performed on each pixel corresponding to the brightness value of the structure 10. As described above, in the TEM image G, the tungsten layer 60 is black, and the carbon layer 50 is white to a lighter gray. In this step, the brightness value of each pixel of the structure 10 is corrected and determined as a relative value between the brightness value of the tungsten layer (0) and the brightness value of the carbon layer (255). Figure 6 (b) is a 3D representation of the brightness values ​​of the corrected image G. If compared with... Figure 5 By comparison, it can be seen that the brightness value in structure 10 is relatively corrected based on the black color of tungsten layer 60 and the white to light gray color of carbon layer 50.

[0208] In TEM image G, the brightness value of each pixel in carbon layer 50 / tungsten layer 60 typically exhibits a slight deviation. To eliminate the effect of this deviation, the brightness value of the tungsten layer is set to 0, and the brightness value of the carbon layer to 255. For the brightness value of tungsten layer 60, the average brightness value is taken from the minimum value in tungsten layer 60 of image G, in descending order, representing the brightness values ​​of a portion equivalent to 10,000 pixels. Similarly, for the brightness value of carbon layer 50, the average brightness value is taken from the maximum value in carbon layer 50, in ascending order, representing the brightness values ​​of a portion equivalent to 100,000 pixels. These respective average values ​​are then used as the brightness values ​​of carbon layer 50 / tungsten layer 60 before correction. The brightness values ​​are corrected in the same way for multiple TEM images G.

[0209] (v): Calculate the brightness Sa

[0210] In this process, the luminance Sa is calculated from the luminance value of the image G obtained through process (iv). Specifically, for each of the aforementioned luminance acquisition regions R (hereinafter, each luminance acquisition region is referred to as R...),... n The least squares method is used to calculate the average of the absolute values ​​of the corrected brightness differences of each pixel, and these averages are used as the region R. n brightness Sa n Then, the region R was obtained based on brightness. 1＋2＋・・・＋n The total area is 6.9μm. 2 The above method sets multiple brightness acquisition areas R n Calculated brightness Sa n The average value is taken as the brightness Sa of structure 10.

[0211] In this invention, in order to improve the correlation between brightness Sa and the physical properties and characteristics of the structure, such as particle resistance, the area of ​​the brightness acquisition region R is set to 6.9 μm when calculating brightness Sa. 2 The above. By determining the brightness Sa based on the area exceeding this area, the relationship between brightness Sa and physical properties can be correctly and appropriately represented in the structure 10, even when deviations in physical properties and characteristics may occur in the defined area.

[0212] Compared to the surface area of ​​structure 10, i.e., the plasma irradiation area, the size of a TEM observation sample 90 is very small. On the other hand, the physical properties and characteristics of the structure, such as particle resistance, are, in principle, required of the entire surface of the structure. In this respect, the present invention requires the total area of ​​the brightness acquisition region R to be 6.9 μm. 2Furthermore, at least three TEM observation samples are prepared from structure 10. That is, in this invention, multiple TEM observation samples are obtained equally from the surface of the structure in order to include as much information as possible about the entire surface of the structure. In addition, when obtaining at least three or more TEM observation samples, it is necessary to take into account including information about the entire surface of the structure.

[0213] There is a correlation between brightness Sa and the physical properties and characteristics of a structure, such as particle resistance. Therefore, according to the present invention, by calculating the brightness Sa of a structure, the actual particle resistance of the structure can be evaluated instead, allowing the particle resistance and other properties of the structure to be understood before its use.

[0214] Focusing on the explanation of the area of ​​the brightness acquisition region R, the process of calculating the brightness Sa is further described in detail.

[0215] To improve the correlation between brightness Sa and anti-particle properties, the brightness acquisition region R in image G is set to have a total area of ​​6.9 μm in this invention. 2 That's all. Specifically, multiple (n) images G are obtained from at least three TEM observations of the sample. n Set region R for each image n Next, the brightness Sa of each image Gn is... n The average value is taken as the brightness Sa of the structure.

[0216] Reference Figure 4 , Figure 6 (a) and Figures 7(a) to (b) illustrate the method for calculating the brightness Sa1 from an image G1.

[0217] like Figure 4 and Figure 6 As shown in (a), a region R1 is defined for an image G1. Within region R1, the longitudinal length dL is set to 0.5 μm. As mentioned earlier, this is because the properties near the surface of a structure are considered to be most relevant to the structure's physical properties and characteristics, such as particle resistance. Furthermore, the lateral length dW of region R1, which is the lateral W, is set to be the longest in image G. As an example, at 100,000x magnification, the lateral length dW is approximately 1.5 μm to 2.0 μm. That is, for a TEM image G1 taken at 100,000x magnification, the area of ​​region R1 can be set to 0.75 to 1.0 μm. 2 .

[0218] Therefore, in this example, the region R used to obtain the brightness is... n The total area is 6.9μm. 2The required number of images G is 7 to 9. On the other hand, as mentioned above, in this invention, at least 3 TEM observation specimens 90 are prepared, and the same number of TEM images G are obtained from each TEM observation specimen 90. Thus, in this example, 3 images G are obtained from one TEM observation specimen 90. As shown in FIG3(b), multiple TEM images G are obtained from one TEM observation specimen 90. n At that time, with multiple images G n It is obtained continuously along the horizontal axis W. Additionally, multiple images G are used. n The dimensions (image vertical length Gl, image horizontal length Gw) are made approximately the same. This, for example, can reduce the influence of measurement bias between observers and further improve the correlation between brightness Sa and anti-particle properties.

[0219] The inventors discovered a correlation between the brightness Sa in a region 0.5 μm away from the surface 10a of the structure and the physical properties and characteristics of the structure, such as particle resistance, as described above. Therefore, in the region R where the brightness Sa is calculated, the longitudinal length dL of the region is set to 0.5 μm. Furthermore, in step (i), as explained using FIG3, since the processing is performed from the surface 10a of the structure 10, even with improved processing accuracy, the lower thickness 90d of the TEM observation sample 90 is still a cone shape where the upper thickness 90u is greater than the lower thickness 90d. Consequently, the greater the depth from the surface 10a of the structure 10, the more difficult it is for the electron beam to pass through, and the less sensitive the brightness value becomes. That is, in the image G, the image becomes darker overall relative to the surface 10a side as it moves towards the depth direction, i.e., it becomes a darker image. Therefore, in order to sufficiently reduce the influence of the sample thickness, it is necessary to set the longitudinal length dL of the region to 0.5 μm.

[0220] When setting the brightness acquisition area R, the longitudinal length dL of the area is set based on the vicinity of the surface 10a of the structure 10. In the TEM image G, when the gap between the surface 10a and the carbon layer 50 is observable, the area R needs to be set to avoid this gap. "Vicinity of the surface 10a" refers to a range of approximately 5 to 50 nm from the surface 10a. For detailed specifications, please refer to the embodiments described later.

[0221] The processing in steps (iii) to (iv) above can be performed continuously and uniformly in image analysis software. WinROOF2015 (available from Mitani Corporation) can be used as such software.

[0222] Furthermore, although it is considered that the smaller the brightness Sa of the composite structure involved in the present invention, the better, those skilled in the art will obviously know that there are actual manufacturing limits. Since such manufacturing limits become the lower limit of brightness Sa in the present invention, not specifying a lower limit does not make the present invention involved in the third aspect unclear. The same applies to the fourth aspect below.

[0223] Fourth aspect of the present invention

[0224] The fourth aspect of the present invention is characterized in that, although brightness Sa is used as an indicator in the same way as in the third aspect of the present invention, a step of removing interference components is added to step (iv) of the method for obtaining brightness Sa in the first aspect, namely the step of correcting the brightness value. Therefore, the description of the third aspect in this specification, except for the step of removing the interference components, becomes the description of the fourth invention.

[0225] Furthermore, the composite structure involved in the fourth aspect of the present invention is as follows:

[0226] It comprises a matrix material and a structure disposed on the matrix material and having a surface, characterized in that,

[0227] The structure comprises polycrystalline ceramics.

[0228] The luminance Sa value calculated using the following method is below 10.

[0229] The method for obtaining the brightness Sa comprises the following steps:

[0230] That is, (i) the process of preparing the sample for observation by a transmission electron microscope (TEM) of the structure;

[0231] (ii) The process of obtaining a digital black-and-white image of the bright-field image of the TEM observation sample;

[0232] (iii) The process of obtaining the brightness value of each pixel in the digital black and white image by representing the color data of each pixel with grayscale values;

[0233] (iv) The process of correcting the brightness value;

[0234] and (v) the process of calculating the luminance Sa using the corrected luminance value.

[0235] In the process (i),

[0236] Prepare at least three TEM observation specimens from the structure.

[0237] At least three TEM observation samples were prepared separately to suppress processing damage using focused ion beam (FIB) method.

[0238] During the FIB processing, a carbon layer and a tungsten layer are formed on the surface of the structure to prevent charging and protect the sample.

[0239] When the FIB processing direction is taken as the longitudinal direction, the length of the minor axis of the structure surface, i.e., the upper thickness of the sample, is 100±30 nm on a plane perpendicular to the longitudinal direction.

[0240] In process (ii),

[0241] The digital black and white images were obtained for each of the at least three TEM observation samples.

[0242] When using a transmission electron microscope (TEM) at 100,000x magnification and 200kV accelerating voltage, the digital black and white image contains the structure, the carbon layer, and the tungsten layer, respectively.

[0243] In the digital black and white image, a brightness region is defined from the surface of the structure, with a longitudinal length of 0.5 μm.

[0244] Multiple digital black-and-white images were obtained from the at least three TEM observation samples, such that the total area of ​​the brightness acquisition region was 6.9 μm. 2 above,

[0245] In the process (iv),

[0246] Regarding the brightness value, the brightness value of the carbon layer is set to 255, and the brightness value of the tungsten layer is set to 0, and a relative correction is performed to obtain the corrected brightness value.

[0247] Regarding the digital black and white image for correcting the brightness value, a low-pass filter is used for interference removal, and the cut-off frequency in the interference removal using the low-pass filter is 1 / (10 pixels).

[0248] In the process (v),

[0249] Regarding the brightness acquisition area, the average of the absolute values ​​of the corrected brightness value differences of each pixel is calculated using the least squares method, and these averages are taken as the brightness Sa.

[0250] Furthermore, the evaluation method involved in this invention is as follows:

[0251] A method for evaluating the microstructure of structures containing polycrystalline ceramics and having a surface, characterized by the following:

[0252] It consists of the following processes,

[0253] That is, (i) the process of preparing the sample for observation by a transmission electron microscope (TEM) of the structure;

[0254] (ii) The process of obtaining a digital black-and-white image of the bright-field image of the TEM observation sample;

[0255] (iii) The process of obtaining the brightness value of each pixel in the digital black and white image by representing the color data of each pixel with grayscale values;

[0256] (iv) The process of correcting the brightness value;

[0257] and (v) the process of calculating the luminance Sa using the corrected luminance value.

[0258] In the process (i),

[0259] Prepare at least three TEM observation specimens from the structure.

[0260] At least three TEM observation samples were prepared separately to suppress processing damage using focused ion beam (FIB) method.

[0261] During the FIB processing, a carbon layer and a tungsten layer are formed on the surface of the structure to prevent charging and protect the sample.

[0262] When the FIB processing direction is taken as the longitudinal direction, the length of the minor axis of the structure surface, i.e., the upper thickness of the sample, is 100±30 nm on a plane perpendicular to the longitudinal direction.

[0263] In process (ii),

[0264] The digital black and white images were obtained for each of the at least three TEM observation samples.

[0265] When using a transmission electron microscope (TEM) at 100,000x magnification and 200kV accelerating voltage, the digital black and white image contains the structure, the carbon layer, and the tungsten layer, respectively.

[0266] In the digital black and white image, a brightness region is defined from the surface of the structure, with a longitudinal length of 0.5 μm.

[0267] Multiple digital black-and-white images were obtained from the at least three TEM observation samples, such that the total area of ​​the brightness acquisition region was 6.9 μm. 2 above,

[0268] In the process (iv),

[0269] Regarding the brightness value, the brightness value of the carbon layer is set to 255, and the brightness value of the tungsten layer is set to 0, and a relative correction is performed to obtain the corrected brightness value.

[0270] Regarding the digital black and white image for correcting the brightness value, a low-pass filter is used for interference removal, and the cut-off frequency in the interference removal using the low-pass filter is 1 / (10 pixels).

[0271] In the process (v),

[0272] Regarding the brightness acquisition area, the average of the absolute values ​​of the corrected brightness value differences of each pixel is calculated using the least squares method, and these averages are taken as the brightness Sa.

[0273] Thus, the composite structure involved in the fourth form is characterized by a brightness Sa of 10 or less, preferably 5 or less.

[0274] In the fourth aspect of the present invention, the following steps are performed to determine the brightness Sa in the same manner as in the third aspect of the present invention: step (i), preparing a transmission electron microscope (TEM) observation sample of the structure; step (ii), preparing a digital black and white image of the bright field image of the TEM observation sample; and step (iii), obtaining a brightness value expressed in grayscale values ​​for the color data of each pixel in the digital black and white image. Furthermore, step (iv) further includes a step of removing interference components from the image as needed, so that the brightness Sa more accurately and appropriately represents the microstructure of the structure. The TEM image G contains interference with high-frequency components, which is removed by a filter in an additional step. In this aspect, a low-pass filter (LPF) is used to remove interference from the image G. For details on interference removal in image processing, refer to "Image Processing - Its Basics to Applications 2nd Edition" (by Hiroshi Ozaki and Keiji Taniguchi, Kyoritsu Publishing Co., Ltd.).

[0275] In this configuration, the cut-off frequency for interference removal using a low-pass filter is set to 1 / (10 pixels). That is, the cutoff period is set to 10 pixels. For example, when using WinROOF2015 as image processing software, the cut-off frequency is set using the interference removal command.

[0276] Figures 7(c) and (d) are examples of images G after brightness value correction, i.e., Figures 7(a) and (b) with the cutoff frequency set to 1 / (10 pixels) and interference removed using a low-pass filter. By removing interference, the influence of the focusing accuracy of the TEM image G can be eliminated, and the correlation between the physical properties and characteristics of the structure, such as particle resistance and brightness Sa, can be improved.

[0277] In the fourth aspect of the present invention, the step (v) of calculating the luminance Sa using the corrected luminance value obtained in this way is performed thereafter. This step (v) may also be the same as in the third aspect of the present invention.

[0278] Fifth aspect of the present invention

[0279] In the fifth aspect of the present invention, unlike the first to fourth aspects, the object is limited to structures containing Y (yttrium) and O (oxygen), and the microstructure of the structure is expressed using refractive index as an indicator. That is, the inventors have successfully achieved minimal particle influence in composite structures containing Y (yttrium) and O (oxygen) used, for example, in semiconductor manufacturing equipment exposed to corrosive plasma environments. Furthermore, it has been discovered that by using refractive index as an indicator, particle resistance performance can be evaluated at an extremely high level.

[0280] The composite structure according to the fifth aspect of the present invention is as follows.

[0281] It includes a matrix material and a structure disposed on the matrix material and having a surface.

[0282] The structure comprises a polycrystalline ceramic containing Y (yttrium) and O (oxygen).

[0283] The refractive index is greater than 1.92 at wavelengths between 400 nm and 550 nm.

[0284] The refractive index was calculated using a microspectral film thickness gauge via reflection spectroscopy.

[0285] As for the measurement conditions, the measurement point size was 10 μm, the average surface roughness Ra of the substrate material surface and the composite structure surface was ≤0.1 μm, the thickness of the structure was ≤1 μm, and the measurement wavelength range was 360–1100 nm.

[0286] As a condition for analysis, the wavelength range for analysis is 360–1100 nm, and the optimization method and the least squares method are used.

[0287] Furthermore, the composite structure involved in another aspect of the present invention is as follows:

[0288] It includes a matrix material and a structure disposed on the matrix material and having a surface.

[0289] The structure comprises a polycrystalline ceramic containing Y (yttrium) and O (oxygen).

[0290] The refractive index satisfies at least one of the following: 1.99 or higher for wavelengths of 400 nm, 1.96 or higher for wavelengths of 500 nm, 1.94 or higher for wavelengths of 600 nm, 1.93 or higher for wavelengths of 700 nm, and 1.92 or higher for wavelengths of 800 nm.

[0291] The refractive index was calculated using a microspectral film thickness gauge via reflection spectroscopy.

[0292] As for the measurement conditions, the measurement point size was 10 μm, the average surface roughness Ra of the substrate material surface and the composite structure surface was ≤0.1 μm, the thickness of the structure was ≤1 μm, and the measurement wavelength range was 360–1100 nm.

[0293] As a condition for analysis, the wavelength range for analysis is 360–1100 nm, and the optimization method and the least squares method are used.

[0294] Generally speaking, the average refractive index of Y₂O₃ is 1.92 (Japan Chemical Society, "Chemical Handbook", Maruzen (1962), p. 919; "Ceramic Chemistry", p. 220, Table 8-24, revised edition of Japan Ceramic Association, September 30, 2017, etc.). Furthermore, the refractive index and reflectance are disclosed in the Journal of the Japan Chemical Society, 1979, (8), pp. 1106-1108 (Non-Patent Document 1) as optical properties of a transparent plate-shaped sample, i.e., yttrium oxide sintered body (see reference). Figure 20 In contrast, the composite structure according to the fifth aspect of the present invention has a refractive index greater than 1.92, for example, at a wavelength of 400 to 550 nm. Alternatively, it satisfies at least one of the following: 1.99 or more at a wavelength of 400 nm, 1.96 or more at a wavelength of 500 nm, 1.94 or more at a wavelength of 600 nm, 1.93 or more at a wavelength of 700 nm, and 1.92 or more at a wavelength of 800 nm or more.

[0295] In the fifth form, although the basic structure of the composite structure is the same as that of the composite structures involved in forms 1 to 4, in... Figure 1 In its basic structure, structure 10 comprises a polycrystalline ceramic (hereinafter sometimes referred to as a "YO compound") containing Y (yttrium) and O (oxygen). Furthermore, structure 10 of the composite structure exhibits a specified refractive index.

[0296] Therefore, the composite structure 10 containing Y (yttrium) and O (oxygen) in the fifth aspect is a so-called YO compound coating. By implementing the YO compound coating, the substrate material 70 can possess various physical properties and characteristics. Furthermore, even in this aspect, ceramic structures and ceramic coatings are used in the same sense unless specifically limited to them.

[0297] According to a preferred embodiment, structure 10 uses polycrystalline ceramic containing YO compounds as its main component, preferably more than 50% YO compounds, more preferably more than 70%, and even more preferably more than 90% or 95%. Most preferably, structure 10 is composed of YO compounds.

[0298] In this configuration, the YO compound is, for example, an oxide of yttrium. Examples include Y₂O₃ and Y₂O₃. α O β (Non-stoichiometric composition). Other elements besides Y and O may be included. For example, YO compounds containing at least one of F, Cl, and Br can be cited. Structure 10, for example, uses Y₂O₃ as the main component. The content of Y₂O₃ is 70% or more, preferably 90% or more, more preferably 95% or more. Most preferably, structure 10 is composed of 100% Y₂O₃.

[0299] Refractive index in the fifth form

[0300] The refractive index can be determined by calculating using a microspectral film thickness gauge (e.g., Otsuka Electronics OPTM-F2, FE-37S) via reflection spectroscopy. As measurement conditions, the measurement point size is set to 10 μm and the measurement wavelength range is set to 360–1100 nm. Furthermore, as resolution conditions, the resolution wavelength range is set to 360–1100 nm, and optimization and least squares methods are employed.

[0301] In the composite structure according to the fifth aspect of the present invention, the refractive index at wavelengths of 400 nm to 550 nm is greater than 1.92, preferably at wavelengths of 400 nm to 600 nm, and more preferably at wavelengths of 400 nm to 800 nm. Furthermore, in the composite structure according to the fifth aspect of the present invention, the refractive index satisfies at least one of the following: 1.99 or higher at wavelengths of 400 nm, 1.96 or higher at wavelengths of 500 nm, 1.94 or higher at wavelengths of 600 nm, 1.93 or higher at wavelengths of 700 nm, and 1.92 or higher at wavelengths of 800 nm or higher. The inventors have newly discovered a new structure in which the refractive index of a composite structure containing a YO compound is increased as described above. Moreover, the present invention was unexpectedly completed by discovering that the composite structure containing a YO compound with an extremely high refractive index exhibits exceptionally excellent anti-particle properties. In a preferred embodiment of the present invention, the upper limit of the refractive index is 2.20.

[0302] Modulation methods for composite structures

[0303] As long as the composite structure involved in this invention can achieve the properties of the first to fifth aspects described above, it can be manufactured by various suitable manufacturing methods. According to one aspect of the invention, the composite structure involved in this invention can be preferably manufactured by forming a structure on a substrate material using the aerosol deposition method (AD method). According to a preferred aspect of the invention, the structure of the composite structure involved in this invention can be realized by the AD method. The AD method is a method in which a gaseous solvent containing particles of brittle materials such as ceramics is sprayed onto the surface of a substrate material, causing the particles to collide with the substrate material at high speed, thereby pulverizing or deforming the particles and forming a structure (ceramic coating) on ​​the substrate material.

[0304] Apparatus for implementing AD method

[0305] While not specifically limited to the apparatus used in the AD method for manufacturing the composite structures described in the first to fifth embodiments of the present invention, it possesses... Figure 10 The basic structure shown is as follows: The device 19 used in the AD method comprises a cavity 14, an atomizing agent supply unit 13, an air supply unit 11, an exhaust unit 18, and piping 12. Inside the cavity 14 are arranged a platform 16 on which the substrate material 70 is disposed; a drive unit 17; and a nozzle 15. The drive unit 17 allows for relative changes in the positions of the substrate material 70 disposed on the platform 16 and the nozzle 15. The distance between the nozzle 15 and the substrate material 70 can be either constant or variable. In this example, although the drive unit 17 drives the platform 16, it can also drive the nozzle 15. The driving direction is, for example, the XYZθ direction.

[0306] exist Figure 10 In the apparatus, the atomizing agent supply unit 13 is connected to the gas supply unit 11 via a pipe 12. The atomizing agent supply unit 13 supplies an aerosol mixture containing raw material particles and gas to the nozzle 15 via the pipe 12. The apparatus 19 also includes a powder supply unit (not shown) for supplying raw material particles. The powder supply unit can be disposed within the atomizing agent supply unit 13 or separately from it. In addition, an aerosol forming unit for mixing raw material particles and gas can be separately provided outside the atomizing agent supply unit 13. By controlling the supply amount from the atomizing agent supply unit 13 in a certain manner so that the amount of particles ejected from the nozzle 15 is constant, a homogeneous structure can be obtained.

[0307] The gas supply unit 11 supplies nitrogen, helium, argon, air, etc. When the supplied gas is air, compressed air with fewer impurities such as moisture and oil is preferred, or an air treatment unit can be provided to remove impurities from the air.

[0308] Next, the operation of the apparatus 19 used in the AD method will be explained. With the matrix material placed in the stage 16 within the cavity 14, the pressure inside the cavity 14 is reduced to below atmospheric pressure by an exhaust section 18, such as a vacuum pump, specifically to about several hundred Pa. On the other hand, the internal pressure of the atomizing agent supply section 13 is set to be higher than the internal pressure of the cavity 14. The internal pressure of the atomizing agent supply section 13 is, for example, several hundred to tens of thousands of Pa. The powder supply section can also be made to atmospheric pressure. By the pressure difference between the cavity 14 and the atomizing agent supply section 13, the particles in the aerosol are accelerated so that the ejection velocity of the raw material particles from the nozzle 15 is in the subsonic to supersonic (50 to 500 m / s) range. The ejection velocity is appropriately controlled by the gas flow rate supplied from the gas supply section 11, the type of gas, the shape of the nozzle 15, the length and inner diameter of the piping 12, and the exhaust volume of the exhaust section 18. For example, a supersonic nozzle such as a Laval nozzle can also be used as the nozzle 15. The particles in the aerosol ejected at high speed from nozzle 15 collide with the substrate material, shattering or deforming them and accumulating as structural elements on the substrate material. By changing the relative position of the substrate material and nozzle 15, a composite structure with a structure having a specified area on the substrate material is formed. Specific manufacturing conditions such as cavity pressure and gas flow rate vary depending on the combination of various devices, and these conditions can be appropriately adjusted within the range that allows the formation of the structure of the present invention.

[0309] Alternatively, a fragmentation section (not shown) can be provided before the particles are ejected from nozzle 15 to de-agglomerate. The fragmentation method in the fragmentation section can be any method, as long as the collision mode of the particles with the matrix material described later is sufficiently satisfied. Examples include mechanical fragmentation such as vibration and impact, as well as known methods such as electrostatic discharge, plasma irradiation, and grading.

[0310] In addition to the above-described applications, the composite structures involved in this invention are also preferably used in the following applications: corrosion-resistant coatings in aerospace industries such as electric vehicles, touch panels, LEDs, solar cells, dental implants, and mirrors for satellites; sliding components; chemical equipment; all-solid-state batteries; thermal barrier coatings; and high-refractive-index applications such as optical lenses, optical mirrors, optical elements, and gemstone jewelry.

[0311] Example

[0312] The present invention will be further illustrated by the following embodiments, but the present invention is not limited to these embodiments.

[0313] 1. Sample preparation

[0314] 1-1 Raw material particles

[0315] Yttrium oxide, yttrium oxyfluoride, yttrium fluoride, alumina powder, and zirconium oxide powder were prepared as raw material particles. The average particle size and particle state of each powder are shown in Table 1.

[0316] Film preparation of samples 1-2

[0317] Composite structures for samples a to d and f to n were fabricated using the raw material particles and the matrix materials shown in Table 1. Sample e was a commercially available sample fabricated by ion sputtering, while the other samples were fabricated by aerosol deposition.

[0318] The basic structure of the device used in the AD method is made the same as... Figure 10 The apparatus shown is as described in Table 1. The raw material particles, matrix material, gas type, and gas flow rate for each sample are prepared as shown in Table 1, with an injection velocity of 150 m / s or higher from the nozzle. Furthermore, the thickness of the structures formed is approximately 5 μm. The structures are formed at room temperature (approximately 20°C).

[0319] 2. Characterization of Structures (Part 1)

[0320] 2-1 Average crystallite size

[0321] For samples e and c, the average crystallite size was calculated using TEM images taken at 400,000x magnification. Specifically, the average crystallite size was calculated by averaging 15 approximately circular crystallites using images obtained at 400,000x magnification.

[0322] Regarding sample c prepared by the AD method, the average crystallite size calculated from the TEM image is 9 nm.

[0323] In sample e, which was fabricated by ion sputtering, the average crystallite size calculated from TEM images was 1 nm.

[0324] 2-2 Porosity determination

[0325] For samples a to h, porosity was calculated using images obtained by scanning electron microscopy (SEM) and image analysis software WinRoof2015. The magnification ranged from 5,000 to 20,000 times. This porosity measurement has been used previously as a method for evaluating the density of structures.

[0326] As a result, the porosity of any one of samples a to h was less than 0.01%. The SEM images of samples a, c, e, f, and g are shown in Figure 12. As will be discussed later, previous porosity measurements of these samples with different particle resistance could not specifically identify differences in their structures.

[0327] 3. Characterization of Structures (Part 2)

[0328] 3-1. Determination of hydrogen content by D-SIMS method

[0329] The samples used for hydrogen content determination were prepared using the following method. First, two samples were prepared for each of the following types: a-c, f, i-k, m, and n. The sample size was 3 mm × 3 mm, and the thickness was 3 mm. For each sample, one was used as a standard sample, and the other was used as the measurement sample. For each sample, the two-dimensional average surface roughness Ra of the surface 10a of the structure 10 was reduced to 0.01 μm by grinding or other methods. Next, for each sample, the hydrogen content was determined by D-SIMS after being placed at room temperature (20-25°C), humidity (60% ± 10%), and atmospheric pressure for more than 24 hours.

[0330] In the determination of hydrogen content by dynamic-secondary ion mass spectrometry (D-SIMS), the CAMECA-manufactured IMF-7f was used as the apparatus.

[0331] The preparation of the standard samples is as follows. Evaluation samples and samples with the same matrix composition as the evaluation samples (i.e., standard samples for the evaluation samples), as well as Si single crystals and standard samples for Si single crystals, are prepared. Of the two prepared samples, one is used as the evaluation sample, and the other as the standard sample for the evaluation sample. The standard sample for the evaluation sample is a sample with the same matrix composition as the evaluation sample, into which deuterium is injected. At the same time, deuterium is also injected into the Si single crystal, and equal amounts of deuterium are injected into both the standard sample for the evaluation sample and the Si single crystal. Then, the amount of deuterium injected into the Si single crystal is made to approximate the amount of deuterium injected. For the standard sample for the evaluation sample, the secondary ion intensities of deuterium and constituent elements are calculated using secondary ion mass spectrometry (D-SIMS), and the interphase sensitivity coefficient is calculated. The hydrogen content of the evaluation sample is calculated using the interphase sensitivity coefficient calculated from the standard sample for the evaluation sample. For other details, refer to ISO 18114, "Determination of relative sensitivity from standards with injected ions" (International Organization for Standardization, Geneva, 2003).

[0332] Conductive platinum (Pt) was vapor-deposited onto the surface of the structures of both the test sample and the standard sample. Cesium (Cs) ions were used as the primary ion species for D-SIMS measurement. The primary accelerating voltage was set to 15.0 kV, the detection area to 8 μm φ, and the measurement depths to three levels: 500 nm, 2 μm, and 5 μm.

[0333] The number of hydrogen atoms per unit volume (atoms / cm) obtained 3 As shown in Table 2 below.

[0334] 3-2. Determination of hydrogen content by RBS-HFS and p-RBS methods

[0335] First, for samples a, c, f, and j, surface 10a of structure 10 was ground to achieve a two-dimensional average surface roughness Ra of 0.01 μm. Next, the samples were placed at room temperature (20-25°C), humidity (60% ± 10%), and atmospheric pressure for more than 24 hours, after which the hydrogen content (hydrogen atom concentration) was measured.

[0336] Hydrogen content was determined by combining RBS-HFS with p-RBS. The apparatus used was a Pelletron 3SDH manufactured by National Electrostatics Corporation.

[0337] The determination conditions for the RBS-HFS method are as follows.

[0338] Injected ion: 4He +

[0339] Incident energy: 2300 keV, incident angle: 75°, scattering angle: 160°, reflection angle: 30°

[0340] Sample current: 2nA, beam diameter: 1.5mmφ, irradiation dose: 8μC

[0341] In-plane rotation: None

[0342] The determination conditions for the p-RBS method are as follows.

[0343] Injected ions: Hydrogen ions (H+) + )

[0344] Incident energy: 1740 keV, incident angle: 0°, scattering angle: 160°, reflection angle: none

[0345] Sample current: 1 nA, beam diameter: 3 mmφ, irradiation dose: 19 μC

[0346] In-plane rotation: None

[0347] The resulting hydrogen atom concentrations are shown in Table 2, which will be described later.

[0348] 3-3-1. Preparation of Samples for TEM Observation

[0349] For samples a to n, TEM observation was performed using focused ion beam (FIB) method. First, each sample was cut. Then, the surface of each sample's structure was processed using FIB. First, a carbon layer of 50 nm was deposited onto the surface of each sample's structure. The target thickness of the carbon layer was approximately 300 nm.

[0350] After depositing the carbon layer, each sample was thinned using a FIB (Film-Induced Blasting) apparatus. First, with the carbon layer facing upwards, a Ga ion beam was irradiated around the thinned area, cutting out a portion of the structure from each sample along with the carbon layer. The cut structure was then fixed to the FIB TEM stage using a tungsten deposition method via FIB selection. Next, a tungsten layer was formed on the carbon layer 50, specifically the thinned area for TEM observation, through tungsten deposition. The target thickness of the tungsten layer was set to 500–600 nm. Then, Ga ions were used to cut the structure from both sides of the thinned area to create TEM observation specimens. The target thickness of these TEM observation specimens was set to 100 nm. The accelerating voltage during FIB processing started at a maximum of 40 kV and was finished at a minimum of 5 kV. This yielded three TEM observation specimens in total.

[0351] Next, the upper thickness of 90 μm in the TEM observation specimen 90 was confirmed. For the TEM observation specimen, two electron images were obtained using a scanning electron microscope (SEM), and the upper thickness of 90 μm was obtained from these two electron images. A HITACHI S-5500 SEM was used. The SEM observation conditions were 200,000x magnification, 2kV accelerating voltage, 40-second scan time, and 2560*1920 pixels. The upper thickness of 90 μm for each TEM observation specimen was obtained by averaging five times using the scale bar of the SEM images. The upper thickness of 90 μm for each sample is shown in Table 1. There is a tendency that when the upper thickness of 90 μm exceeds 100±30 nm and is relatively large, the brightness Sa decreases; conversely, when the upper thickness of 90 μm exceeds 100±30 nm and is relatively small, the brightness Sa increases. Regarding sample g, although it is considered that the upper thickness of 138 nm is larger than the specified range, i.e., the brightness Sa is smaller than it should be, it was also confirmed that this is outside the scope of this invention.

[0352] 3-3-2. Imaging of TEM Bright Field Images

[0353] Samples a to n obtained through FIB processing were imaged using TEM in bright-field mode. A transmission electron microscope H-9500 (manufactured by Hitachi High Technology Co., Ltd.) was used with an accelerating voltage of 200kV and a magnification of 100,000x. Images were captured using a digital camera (OneView Camera Model 1095 / Gatan) at 4096×4096 pixels, a shooting speed of 6fps, an exposure time of 2sec, and the image capture mode set to exposure time mode, with the camera positioned low. TEM digital black-and-white images were obtained with the carbon and tungsten layers deposited during sample preparation within the same field of view.

[0354] Figure 13 shows the TEM images of samples a to g, i, j, and l taken at 100,000x magnification. For each TEM observation sample, three TEM images were obtained in a continuous manner in the horizontal direction, resulting in a total of nine TEM images for each sample.

[0355] 3-3-3. Calculate the brightness Sa from the brightness value obtained and the image resolution.

[0356] The brightness values ​​of the acquired TEM bright-field images were obtained using the image analysis software WinROOF2015. Specifically, as shown in Figure 13, for each image G, the brightness acquisition region R was set with the area near the surface 10a of the structure as the base point, and the region's vertical length dL was set to 0.5 μm, and the region's horizontal length dw was approximately the same as the horizontal length Gw of image G. For each brightness acquisition region R, the brightness value of each pixel was obtained, and the brightness values ​​were relatively corrected by taking the brightness of the tungsten layer in region R as 0 and the brightness of the carbon layer as 255. Here, for the brightness value of the tungsten layer, the average value of the brightness value of a portion equivalent to 10,000 pixels was taken continuously in smaller order from the minimum brightness value of the tungsten layer in the TEM image. In addition, for the brightness value of the carbon layer, the average value of the brightness value of a portion equivalent to 100,000 pixels was taken continuously in larger order from the maximum brightness value of the carbon layer. The respective average values ​​obtained here were processed as the brightness values ​​of the carbon layer / tungsten layer before correction.

[0357] For each of the aforementioned brightness acquisition regions R, the average of the absolute values ​​of the corrected brightness value differences for each pixel is calculated using the least squares method. The average of these values ​​obtained from nine TEM images is taken as the brightness Sa. The total area of ​​the brightness acquisition regions R at this point is 6.9 μm. 2 above.

[0358] Furthermore, as shown in Figures 13(e), (f), and (g), when the interface between the surface 10a of the structure 10 and the tungsten layer 50 is not a straight line, the brightness acquisition area R is set to avoid this area. Additionally, as shown in Figure 13(e), when the unevenness of the surface 10a of the structure 10 is observed, the longitudinal length dL of the area is set starting from the part closest to the surface 10a.

[0359] The obtained brightness Sa values ​​are shown in Table 2 below.

[0360] 3-4. Calculate the brightness Sa after removing interfering components.

[0361] In step 3-3-3, which involves obtaining the brightness value and calculating the brightness Sa from the image analysis, the image analysis software WinROOF2015 is set to a mode that removes interference components to obtain the brightness value of the image.

[0362] The obtained brightness Sa values ​​are shown in Table 2 below.

[0363] 3-5. Calculation of Refractive Index

[0364] Regarding samples a and c, the surface 10a of structure 10 is ground to make the two-dimensional average surface roughness Ra less than 0.1 μm and the thickness of structure 10 less than 1 μm.

[0365] The refractive index was determined using a microspectroscopic film thickness gauge (Otsuka Electronics OPTM-F2 or Otsuka Electronics FE-37S) by reflection spectroscopy. The measurement conditions were set to a measurement point size of 10 μm and a measurement wavelength range of 360–1100 nm.

[0366] The analysis conditions are as follows: the analysis wavelength range is set to 360–1100 nm, and the optimization method and least squares method are used. The refractive index of each sample at each wavelength is shown in Table 3 below. Figure 19 As shown.

[0367] As shown in Table 3 and Figure 19 As shown, the refractive index of the structure containing the YO compound involved in this invention is greater than that of the known Y2O3 (1.92), and it has higher anti-particle properties.

[0368] 4. Evaluation of structural characteristics

[0369] 4-1. Evaluation of Plasma Resistance

[0370] For samples a to n, a "benchmark anti-plasma test" was performed.

[0371] In the specific experiment, an inductively coupled plasma reactive ion etching (ICP) device (Muc-21 Rv-Aps-Se / Sumitomo Precision Industries) was used as the plasma etching apparatus. The plasma etching conditions were as follows: ICP output of 1500W as power supply, bias output of 750W, a mixture of 100ccm CHF3 gas and 10ccm O2 gas as process gas, pressure of 0.5Pa, and plasma etching time of 1 hour.

[0372] The surface 10a of the structure 10 after plasma irradiation was photographed using SEM. These are shown in Figure 14. As for the SEM observation conditions, the magnification was set to 5000x and the accelerating voltage was set to 3kV.

[0373] Next, the area of ​​corrosion marks on the surface after plasma irradiation was calculated from the obtained SEM images. The results are shown in Table 2.

[0374] In addition, the surface 10a of the structure 10 after plasma irradiation was photographed using a laser microscope. Specifically, an OLS4500 laser microscope was used, with an MPLAPON100xLEXT objective lens (numerical aperture 0.95, working distance 0.35 mm, focal diameter 0.52 μm, measurement area 128 × 128 μm) and a magnification of 100x. The λc filter to remove fluctuation components was set to 25 μm. Measurements were taken at three random locations, and the average value was taken as the arithmetic mean height Sa. Furthermore, the international standard for three-dimensional surface properties, ISO 25178, was appropriately referenced. The values ​​of the arithmetic mean height Sa of the surface 10a after plasma irradiation are shown in Table 4.

[0375] Figure 15 It is the corrosion scar area (μm) of each sample. 2 The curve graph. Like Figure 15 As shown, the sample formed by aerosol deposition has a smaller total corrosion area and better results compared to the sample formed by ion sputtering (e).

[0376] Figure 16 The brightness Sa and corrosion scar area (μm) of each sample formed by aerosol deposition are then expressed. 2 The relationship between ( ). For example, Figure 16 As shown, it is known that by setting the brightness Sa below a specified value, the area of ​​corrosion marks can be significantly reduced.

[0377] In addition, such as Figure 17 As shown in Table 2, it is known that particle resistance can be improved by reducing the amount of hydrogen on the surface of the structure (number of hydrogen atoms per unit volume / hydrogen atom concentration).

[0378] Table 1

[0379]

[0380] Table 2

[0381]

[0382] Table 3

[0383]

[0384] Table 4

[0385]

Claims

1. An evaluation method for evaluating the microstructure of a structure containing polycrystalline ceramics and having a surface, used in environments requiring particle resistance, characterized in that, It consists of the following processes, That is, (i) the process of preparing a transmission electron microscope (TEM) to observe the sample of the structure; (ii) The process of preparing a digital black-and-white image of the bright-field image of the TEM observation sample; (iii) The process of obtaining the brightness value of each pixel in the digital black and white image by representing the color data of each pixel with grayscale values; (iv) The process of correcting the brightness value; (v) The process of calculating the luminance Sa using the corrected luminance value. In the process (i), Prepare at least three TEM observation specimens from the structure. At least three TEM observation samples were prepared by suppressing processing damage using the focused ion beam (FIB) method. During the FIB processing, a carbon layer and a tungsten layer are formed on the surface of the structure. When the FIB processing direction is taken as the longitudinal direction, the length of the minor axis of the structure surface, i.e., the upper thickness of the sample, is 100±30 nm on a plane perpendicular to the longitudinal direction. In process (ii), The digital black and white images were obtained for each of the at least three TEM observation samples. When using a transmission electron microscope (TEM) at 100,000x magnification and 200kV accelerating voltage, the digital black and white images respectively contain the structure, the carbon layer, and the tungsten layer. In the digital black and white image, a brightness region is defined from the surface of the structure, with a longitudinal length of 0.5 μm. Multiple digital black-and-white images were obtained from the at least three TEM observation samples, such that the total area of ​​the brightness acquisition region was 6.9 μm. 2 above, In the process (iv), Regarding the brightness value, the brightness value of the carbon layer is set to 255, and the brightness value of the tungsten layer is set to 0, and a relative correction is performed to obtain the corrected brightness value. In the process (v), Regarding the brightness acquisition area, the average of the absolute values ​​of the corrected brightness value differences of each pixel is calculated using the least squares method, and these averages are taken as the brightness Sa.

2. The evaluation method according to claim 1, characterized in that, The process (iv) also includes the following processes: That is, regarding the digital black and white image with the corrected brightness value, the process of removing interference using a low-pass filter, wherein the cut-off frequency in the interference removal using the low-pass filter is 1 / (10 pixels).

3. The evaluation method according to claim 1 or 2, characterized in that, The method for suppressing the processing damage is at least one of the following: finishing with a low voltage of 5kV, removing the processing damage with Ar ions, and surface cleaning by ion milling before performing the TEM observation.

4. The evaluation method according to claim 1 or 2, characterized in that, The thickness of the upper part of the sample is obtained by using two electron images (SEM) obtained from the TEM observation sample. The SEM observation conditions were 200,000x magnification, 2kV accelerating voltage, 40-second scan time, and 2560×1920 pixels. The SEM image forms a plane perpendicular to the longitudinal direction.

5. The evaluation method according to claim 1 or 2, characterized in that, The at least three TEM observation samples were obtained equally from the surface of the structure.

6. The evaluation method according to claim 1 or 2, characterized in that, In acquiring the digital black and white image, the focus is adjusted at a magnification of more than 300,000 times, and then the digital black and white image is obtained at a magnification of 100,000 times.

7. The evaluation method according to claim 1 or 2, characterized in that, in Within the brightness acquisition area, the horizontal length of the area is set in a manner that is the longest in the digital black and white image, perpendicular to the vertical length of the area.

8. The evaluation method according to claim 1 or 2, characterized in that, When acquiring the plurality of digital black and white images from the at least three TEM observation samples, the plurality of digital black and white images are acquired in a continuous manner in the transverse direction perpendicular to the longitudinal direction of the digital black and white images.

9. The evaluation method according to claim 1 or 2, characterized in that, Image analysis software is used in each of the steps (iii) to (iv).

Images