Sample holder
The sample holder design with a ceramic body, base plate, cylindrical member, and porous body with matching thermal expansion coefficients and strategic gaps addresses heat uniformity issues by stabilizing gas flow and preventing cracks, maintaining consistent temperature distribution.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- KYOCERA CORP
- Filing Date
- 2026-01-15
- Publication Date
- 2026-07-23
AI Technical Summary
Sample holders used in semiconductor manufacturing face challenges in maintaining heat uniformity under extreme temperature conditions due to stress and potential cracking of porous materials, which affects gas flow uniformity.
A sample holder design featuring a ceramic body, base plate, cylindrical member, and porous body with specific structural configurations, including gaps and materials matching thermal expansion coefficients, to stabilize gas flow and prevent cracking.
The design maintains excellent heat uniformity by stabilizing gas flow and reducing the likelihood of cracks, even under high-temperature conditions, ensuring consistent temperature distribution.
Smart Images
Figure JP2026001119_23072026_PF_FP_ABST
Abstract
Description
Sample holder
[0001] The embodiments of the disclosure relate to a sample holder.
[0002] Sample holders used in semiconductor manufacturing equipment and the like are well known. A sample holder has a structure in which a ceramic body on which a workpiece such as a wafer is placed and a conductive base plate that supports this ceramic body are joined together via a bonding material.
[0003] This type of sample holder has through-holes that penetrate the ceramic body and the base plate, through which a gas such as helium is supplied to the back surface of the object to be processed, which is placed on the ceramic body.
[0004] Inside the aforementioned through-holes, a porous body made of an insulator is located to suppress arcing. A dense body (a membrane in Patent Document 1) is located around the outer periphery of this porous body.
[0005] Japanese Patent Publication No. 2014-209615
[0006] The sample holder of this disclosure comprises a ceramic body, a base plate, a cylindrical member, and a porous body. The ceramic body has a sample holding surface and a first through-hole. The base plate has a second through-hole connected to the first through-hole and supports the ceramic body. The cylindrical member is located inside at least one of the first and second through-holes and has a third through-hole connected to the first through-hole. The porous body is located inside the third through-hole. The third through-hole has a first hole portion having an inner circumferential surface and a bottom surface, and a second hole portion connected to the bottom surface and having a smaller diameter than the first hole portion. The porous body is located in the first hole portion so as to be in contact with the bottom surface. There is a gap between the inner circumferential surface and the bottom surface and the porous body that is larger than the diameter of the particles constituting the porous body.
[0007] Figure 1 is a cross-sectional view showing an example of the configuration of a sample holder according to the embodiment. Figure 2 is a longitudinal cross-sectional view showing an example of the configuration of a cylindrical member and a porous body according to the embodiment. Figure 3 is an enlarged longitudinal cross-sectional view showing an example of the configuration of a gap and its surroundings according to the embodiment. Figure 4 is a transverse cross-sectional view of a portion including a gap according to the embodiment. Figure 5 is an enlarged longitudinal cross-sectional view showing another example of the configuration of a gap and its surroundings according to the embodiment. Figure 6 is an enlarged longitudinal cross-sectional view showing another example of the configuration of a gap and its surroundings according to the embodiment. Figure 7 is a diagram showing an example of the configuration of each crystal in the cylindrical member and porous body according to the embodiment. Figure 8 is a diagram showing another example of the configuration of each crystal in the cylindrical member and porous body according to the embodiment. Figure 9 is a diagram showing another example of the configuration of each crystal in the cylindrical member and porous body according to the embodiment. Figure 10 is a longitudinal cross-sectional view showing another example of the configuration of a cylindrical member and a porous body according to the embodiment.
[0008] The embodiments for implementing the sample holder according to this disclosure (hereinafter referred to as "Embodiments") will be described in detail below with reference to the drawings. However, this disclosure is not limited by these embodiments. Furthermore, each embodiment can be combined as appropriate, provided that the processing content is not inconsistent. Also, the same parts are denoted by the same reference numerals in each of the following embodiments, and redundant descriptions are omitted.
[0009] Furthermore, in the embodiments described below, expressions such as "vertical" or "parallel" may be used, but these expressions do not require strict vertical or parallel alignment. In other words, each of the above expressions allows for deviations such as manufacturing accuracy and installation accuracy.
[0010] Sample holders used in semiconductor manufacturing equipment and the like are well known. A sample holder has a structure in which a ceramic body on which a workpiece such as a wafer is placed and a conductive base plate that supports this ceramic body are joined together via a bonding material.
[0011] This type of sample holder has through-holes that penetrate the ceramic body and the base plate, through which a gas such as helium is supplied to the back surface of the object to be processed, which is placed on the ceramic body.
[0012] Inside the aforementioned through-holes, a porous body made of an insulator is located to suppress arcing. A dense body (a membrane in the above-mentioned Patent Document 1) is located around the outer periphery of this porous body.
[0013] In recent years, sample holders have been used in high-temperature environments exceeding 300°C and low-temperature environments ranging from -40°C to -100°C. Under these temperature conditions, the porous material is subjected to significant stress, and if cracks develop in the porous material, the gas flow within the porous material can change, potentially reducing the uniformity of the sample holder's temperature.
[0014] Therefore, it is hoped that the above problems will be solved and a sample holder that does not easily lose its excellent heat uniformity will be realized.
[0015] Figure 1 is a cross-sectional view showing an example of the configuration of the sample holder 1 according to the embodiment. Figure 2 is a longitudinal cross-sectional view showing an example of the configuration of the cylindrical member 30 and porous body 40 according to the embodiment, and is an enlarged view of the R1 portion shown in Figure 1.
[0016] As shown in Figure 1, the sample holder 1 may comprise a ceramic body 10, a base plate 20, a plurality of cylindrical members 30, a plurality of porous bodies 40, and a bonding layer 50. The sample holder 1 may also be constructed by bonding a disc-shaped base plate 20 made of metal to the underside of a disc-shaped ceramic body 10.
[0017] The sample holder 1 may have multiple gas holes. These gas holes may penetrate from the first surface 10a of the ceramic body 10, which is the top surface of the sample holder 1, to the fourth surface 20b of the base plate 20, which is the bottom surface of the sample holder 1.
[0018] And, through such a plurality of gas holes, a heat conductive gas such as helium may be flowed from the bottom of the sample holder 1 to the first surface 10a which is the sample holding surface. Specifically, the gas may flow in the order of the third through hole 31, the porous body 40, and the first through hole 11.
[0019] By flowing a heat conductive gas through this gas hole, the gas is supplied to the back surface of the object to be processed (not shown) placed on the first surface 10a, and the heat transfer between the object to be processed and the ceramic body 10 is improved.
[0020] The ceramic body 10 may be made of ceramic. The ceramic body 10 may be formed by molding a raw material containing ceramic into a flat plate shape, for example, a disc shape. The ceramic body 10 is, for example, alumina (Al ２ O ３ ), aluminum nitride (AlN), yttria (Y ２ O ３ ), cordierite (2MgO·2Al ２ O ３ ·5SiO ２ ), silicon carbide (SiC) or silicon nitride (Si ３ N ４ ) and the like may be included as a main component.
[0021] The ceramic body 10 may have a first surface 10a which is a sample holding surface and a second surface 10b located opposite to the first surface 10a. The second surface 10b may be a surface joined to the base plate 20 through a joining layer 50 described later.
[0022] The ceramic body 10 may have a plurality of first through holes 11 penetrating the first surface 10a and the second surface 10b. This first through hole 11 may constitute a part of the aforementioned gas hole in the sample holder 1.
[0023] Note that, since the sample holder 1 according to the embodiment is an electrostatic chuck that holds the object to be processed by an electrostatic force, as shown in FIG. 1, an electrode 12 for electrostatic adsorption may be provided inside the ceramic body 10 which is an insulator. This electrode 12 is a thin flat conductor layer. The electrode 12 may be located, for example, parallel to the first surface 10a of the ceramic body 10.
[0024] The electrode 12 may be made of a conductor mainly composed of a metal such as molybdenum (Mo), platinum (Pt), or tungsten (W). When a voltage is applied to the electrode 12 from the outside, an electrostatic force is generated between the first surface 10a and the object to be processed, thereby attracting and holding the object to be processed.
[0025] Note that while Figure 1 shows an example where two electrodes 12 are observed, the number of electrodes 12 is not limited to this.
[0026] The base plate 20 is a disc-shaped member and may support the ceramic body 10. The base plate 20 may be bonded to the second surface 10b of the ceramic body 10 via a bonding layer 50. The base plate 20 may be made of a metal such as aluminum.
[0027] The base plate 20 may have a third surface 20a that is joined to the ceramic body 10 via a bonding layer 50 described later, and a fourth surface 20b located opposite the third surface 20a. The base plate 20 may have a second through-hole 21 that penetrates between the third surface 20a and the fourth surface 20b. The second through-hole 21 may constitute part of the gas holes in the sample holder 1.
[0028] In this disclosure, the base plate 20 may also function as a high-frequency electrode to which high-frequency power for plasma generation is applied.
[0029] The cylindrical member 30 is a cylindrical member made of an insulating material and may be located inside at least one of the first through-hole 11 and the second through-hole 21. For example, the cylindrical member 30 may be positioned to cover the inner circumferential surface of the second through-hole 21 in the base plate 20. This makes it less likely for the inner circumferential surface of the second through-hole 21, which is a metal surface, to be exposed to plasma entering the gas hole.
[0030] As the insulating material constituting the cylindrical member 30, for example, a ceramic material can be used. Examples of such ceramic materials include alumina or aluminum nitride.
[0031] The cylindrical member 30 may have a third through-hole 31 connected to the first through-hole 11. This third through-hole 31 may have a first hole portion 31a and a second hole portion 31b, as shown in Figure 2.
[0032] The first hole 31a may be located closer to the first through hole 11 (see Figure 1), i.e., closer to the ceramic body 10 (see Figure 1), than the second hole 31b. The first hole 31a may have a bottom surface 31a1 and an inner circumferential surface 31a2.
[0033] The bottom surface 31a1 is, for example, a surface that extends in a direction perpendicular to the axial direction (Z-axis direction in the figure) of the third through hole 31. The bottom surface 31a1 forms an annular shape, for example, around the central axis of the cylindrical member 30. The inner circumferential surface 31a2 is, for example, a surface that extends along the axial direction of the third through hole 31. The inner circumferential surface 31a2 forms a cylindrical shape, for example, around the central axis of the cylindrical member 30.
[0034] The second hole 31b is connected to the first hole 31a and may have a smaller diameter than the first hole 31a. The second hole 31b may have an inner circumferential surface 31b1. The inner circumferential surface 31b1 is, for example, a surface that extends along the axial direction of the third through hole 31. The diameter can be confirmed by preparing a sample in which a region like that shown in Figure 2 can be observed and using a metallurgical microscope or the like.
[0035] The porous body 40 may be located inside the cylindrical member 30. The porous body 40 may be located in the first hole 31a of the cylindrical member 30, for example, so as to be in contact with the bottom surface 31a1. Alternatively, the porous body 40 may be located in the gas hole near the joint between the ceramic body 10 and the base plate 20.
[0036] The material of the porous body 40 may be, for example, alumina or other ceramics. The porous body 40 only needs to have enough voids to allow gas flow. The porosity of the porous body 40 may be, for example, 20% or more and 60% or less.
[0037] The porous body 40 may be columnar, such as cylindrical. The cylindrical member 30 and the porous body 40 may be joined, for example, by firing them integrally, or may be joined using a joining material.
[0038] The porous body 40 functions as a gas flow path, and has a function of reducing the plasma generated above the first surface 10a, which is a sample holding surface, from entering the inside of the gas holes through the first through holes 11 and flowing downward (here, in the negative Z-axis direction).
[0039] As shown in FIG. 2, the sample holder 1 according to the embodiment may have a gap 60. This gap 60 may be located between the bottom surface 31a1 and the inner peripheral surface 31a2 of the first hole portion 31a and the porous body 40. In other words, the gap 60 may be located between the corner portion 31a3 (see FIG. 3) connected to each of the bottom surface 31a1 and the inner peripheral surface 31a2 and the porous body 40.
[0040] FIG. 3 is an enlarged longitudinal sectional view showing an example of the configuration of the gap 60 and its surroundings according to the embodiment, and is an enlarged view of the R2 portion shown in FIG. 2.
[0041] Here, in the embodiment, as shown in FIG. 3, the gap 60 may be larger than the diameter of the particles P1 constituting the porous body 40. In the present disclosure, "larger than the diameter of the particles P1 constituting the porous body 40" means that the size is larger than the particle P1 having the largest diameter among the plurality of particles P1 constituting the porous body 40.
[0042] The comparison of the size between the gap 60 and the particle P1 having the largest diameter can be confirmed by preparing a sample in which a region as shown in FIG. 3 can be confirmed and using a scanning electron microscope (SEM: Scanning Electron Microscope).
[0043] Thereby, in the plurality of particles P1 constituting the porous body 40, even if the directions of thermal expansion or thermal contraction are different from each other, since the gap 60 is larger than the diameter of the particles P1, no matter which direction the particles P1 are distorted, this distortion can be relaxed.
[0044] Therefore, even when the operating environment of the sample holder 1 becomes high temperature, cracks are less likely to occur in the porous body 40. Accordingly, according to this embodiment, the gas flow inside the porous body 40 can be stabilized, making it possible to realize a sample holder 1 that does not easily lose its excellent heat uniformity.
[0045] Furthermore, in this embodiment, even when the operating environment of the sample holder 1 becomes high temperature, cracks are less likely to occur in the porous body 40, thereby reducing the change in the thermal conductivity characteristics of the porous body 40 due to such cracks. Therefore, according to this embodiment, a sample holder 1 that maintains excellent heat uniformity can be realized.
[0046] Furthermore, in this embodiment, when viewed in cross-section along the axial direction of the third through-hole 31, the first length L1, which is the length of the gap 60 at the bottom surface 31a1, and the second length L2, which is the length of the gap 60 at the inner circumferential surface 31a2, may both be smaller than 1 / 4 of the diameter D of the porous body 40 (see Figure 2).
[0047] In this way, by making the first length L1 and second length L2 of the gap 60 smaller than 1 / 4 of the diameter D of the porous body 40, convection of gas flowing in a way that entrains the first hole 31a due to the upward flowing gas is promoted. This allows mutual diffusion between the gas flowing inside the porous body 40 and the gas located in the gap 60.
[0048] Therefore, according to this embodiment, the temperature of the cylindrical member 30, the porous body 40, and the gap 60 can be made uniform, thus realizing a sample holder 1 that is less prone to a decrease in excellent heat uniformity.
[0049] Furthermore, in this embodiment, the main component of the porous body 40 may be the same as the main component of the cylindrical member 30. For example, in this embodiment, both the main component of the porous body 40 and the main component of the cylindrical member 30 may be alumina.
[0050] As a result, the thermal expansion coefficient of the porous body 40 and the thermal expansion coefficient of the cylindrical member 30 become almost the same, so that even when the operating environment of the sample holder 1 becomes high temperature, stress is less likely to be applied to the porous body 40.
[0051] Therefore, according to this embodiment, cracks are less likely to occur in the porous body 40, and the gas flow inside the porous body 40 can be stabilized, thus realizing a sample holder 1 that does not easily suffer from a decrease in excellent heat uniformity.
[0052] Furthermore, in this disclosure, the fact that the main components of the two parts are the same can be confirmed, for example, by the following method. First, a predetermined part of the sample holder 1 is removed by a known method such as cutting, slicing, or polishing. Next, the removed part is thinned using a known method such as argon ion milling to obtain a sample.
[0053] Then, by examining the components using energy-dispersive X-ray spectroscopy (EDS) or wavelength-dispersive X-ray spectroscopy (WDS) with a scanning electron microscope (SEM), it is possible to confirm whether the main components of the two sites are the same.
[0054] Figure 4 is a cross-sectional view of the portion including the gap 60 according to the embodiment. As shown in Figure 4, in this embodiment, the gap 60 may be annular. For example, if the porous body 40 is cylindrical, the gap 60 may be annular.
[0055] As described above, since the strain directions of the multiple particles P1 (see Figure 3) are irregular, twisting strain may occur in the porous body 40. Therefore, in this embodiment, by making the gap 60 annular, this twisting strain can be mitigated.
[0056] Therefore, even when the operating environment of the sample holder 1 becomes high temperature, cracks are less likely to occur in the porous body 40. Accordingly, according to this embodiment, the gas flow inside the porous body 40 can be stabilized, making it possible to realize a sample holder 1 that does not easily lose its excellent heat uniformity.
[0057] Figure 5 is an enlarged longitudinal cross-sectional view showing another example of the configuration of the gap 60 and its surroundings according to the embodiment. As shown in Figure 5, in this disclosure, the corners 41 of the porous body 40 that constitute a part of the gap 60 may have an R shape. In other words, in the example of Figure 5, the gap 60 may extend along the bottom surface 31a1 and the inner circumferential surface 31a2 of the first hole 31a.
[0058] In this way, because the corners 41 of the porous body 40 have an R shape, stress is less likely to be applied to the corners 41 even when the operating environment of the sample holder 1 becomes high temperature, thus making it less likely for cracks to occur in the corners 41.
[0059] Therefore, as shown in the example in Figure 5, the gas flow inside the porous body 40 can be stabilized, making it possible to realize a sample holder 1 that does not easily suffer from a decrease in excellent heat uniformity.
[0060] Figure 6 is an enlarged longitudinal cross-sectional view showing another example of the configuration of the gap 60 and its surroundings according to the embodiment. As shown in Figure 6, in this disclosure, when viewed in cross-section in the axial direction of the third through hole 31, the corner 31a3 where the bottom surface 31a1 and the inner circumferential surface 31a2 of the first hole 31a may be obtuse.
[0061] In this way, by making the corner 31a3 of the first hole 31a obtuse, the angle at which the porous body 40 contacts the bottom surface 31a1 at the corner of the gap 60, and the angle at which the porous body 40 contacts the inner circumferential surface 31a2 at the corner of the gap 60 can be reduced. This makes it possible to alleviate stress concentration at the corner of the gap 60.
[0062] Therefore, even when the operating environment of the sample holder 1 becomes high temperature, cracks are less likely to occur in the porous body 40. Accordingly, as shown in the example in Figure 6, the gas flow inside the porous body 40 can be stabilized, making it possible to realize a sample holder 1 that does not easily lose its excellent heat uniformity.
[0063] Figure 7 shows an example of the crystal structure in the cylindrical member 30 and porous body 40 according to the embodiment. As shown in Figure 7, in the embodiment, the particles P1 constituting the porous body 40 may be in point contact with the particles P2 constituting the cylindrical member 30. In other words, in the embodiment, the porous body 40 may be in point contact with the cylindrical member 30.
[0064] This allows the stress transmitted to the porous body 40 via the cylindrical member 30 to be dispersed. Therefore, according to this embodiment, cracks are less likely to occur in the porous body 40, and the gas flow inside the porous body 40 can be stabilized, thus realizing a sample holder 1 that does not easily lose excellent heat uniformity.
[0065] Figure 8 shows another example of the configuration of each crystal in the cylindrical member 30 and porous body 40 according to the embodiment. As shown in Figure 8, in this disclosure, a plurality of glass particles P3 may be located in at least a portion of the area where the porous body 40 and the cylindrical member 30 are in point contact. These particles P3 may, for example, mainly consist of silica glass.
[0066] For example, if a sample is prepared in which a region like that shown in Figure 8 can be observed, and particles in the area where the crystals constituting the porous body 40 and the crystals constituting the cylindrical member 30 are similar are confirmed to be mainly composed of Si by EDS or WDS using a SEM, and O is also confirmed, then silica glass can be considered to be present.
[0067] As a result, even if the directions of thermal expansion or contraction of the multiple particles P1 constituting the porous body 40 are different from each other, the glass (particle P3) will try to deform uniformly, so the porous body 40 will not become brittle no matter which direction the particles P1 deform.
[0068] Therefore, even when the operating environment of the sample holder 1 becomes high temperature, cracks are less likely to occur in the porous body 40. Accordingly, as shown in the example in Figure 8, the gas flow inside the porous body 40 can be stabilized, making it possible to realize a sample holder 1 that does not easily lose its excellent heat uniformity.
[0069] Figure 9 shows another example of the configuration of each crystal in the cylindrical member 30 and porous body 40 according to the embodiment. As shown in Figure 9, in this disclosure, the sample holder 1 may have a plurality of particles P4 and a plurality of particles P5 in addition to the plurality of particles P3 described above.
[0070] Particle P4 is located at the grain boundary of ceramic particles P2 that constitute the cylindrical member 30, and may be made of glass, for example. Particle P5 is located at the grain boundary of ceramic particles P1 that constitute the porous body 40, and may be made of glass, for example.
[0071] Furthermore, in the example shown in Figure 9, the main component of particle P3 located between the porous body 40 and the cylindrical member 30 may be the same as the main component of particle P4 located inside the cylindrical member 30. For example, in the example shown in Figure 9, both the main component of particle P3 and the main component of particle P4 may be silica glass.
[0072] To confirm that the main components of both particle P3 and particle P4 are silica glass, each particle is used as a measurement area, and it is sufficient if Si is confirmed as the main component and O is also confirmed using EDS or WDS with a SEM.
[0073] In this way, by making the main component of particle P3 the same as the main component of particle P4, the thermal expansion curves of particle P3 and particle P4 can be made to match. As a result, particle P3 becomes less prone to cracking, and even if the multiple particles P1 constituting the porous body 40 are strained in any direction, particle P3, which tends to strain uniformly, is more likely to remain unbroken.
[0074] Therefore, even when the operating environment of the sample holder 1 becomes high temperature, cracks are less likely to occur in the porous body 40. Accordingly, as shown in the example in Figure 9, the gas flow inside the porous body 40 can be stabilized, making it possible to realize a sample holder 1 that does not easily lose excellent heat uniformity.
[0075] Furthermore, in the example shown in Figure 9, by making the main components of particle P3 and particle P4 the same, the heat conduction inside the cylindrical member 30 and the heat conduction between the cylindrical member 30 and the porous body 40 become approximately the same. Therefore, according to the example shown in Figure 9, a sample holder 1 with excellent uniform heat distribution that is less likely to deteriorate can be realized.
[0076] Furthermore, in the example shown in Figure 9, the main component of particle P3 located between the porous body 40 and the cylindrical member 30 may be the same as the main component of particle P5 located inside the porous body 40. For example, in the example shown in Figure 9, both the main component of particle P3 and the main component of particle P5 may be silica glass.
[0077] In this way, by making the main component of particle P3 the same as the main component of particle P5, the thermal expansion curves of particle P3 and particle P5 can be made to match. As a result, particle P3 becomes less prone to cracking, and even if the multiple particles P1 constituting the porous body 40 are strained in any direction, particle P3, which tends to strain uniformly, is more likely to remain unbroken.
[0078] Therefore, even when the operating environment of the sample holder 1 becomes high temperature, cracks are less likely to occur in the porous body 40. Accordingly, as shown in the example in Figure 9, the gas flow inside the porous body 40 can be stabilized, making it possible to realize a sample holder 1 that does not easily lose excellent heat uniformity.
[0079] Furthermore, in the example shown in Figure 9, by making the main components of particle P3 and particle P5 the same, the heat conduction inside the porous body 40 and the heat conduction between the cylindrical member 30 and the porous body 40 become approximately the same. Therefore, according to the example shown in Figure 9, a sample holder 1 with excellent uniform heat distribution that is less likely to deteriorate can be realized.
[0080] Figure 10 is a longitudinal cross-sectional view showing another example of the configuration of the cylindrical member 30 and the porous body 40 according to the embodiment. As shown in Figure 10, in this disclosure, the diameter of the porous body 40 increases toward the first surface 10a (see Figure 1), which is the sample holding surface, and the thickness of the cylindrical member 30 may decrease toward the first surface 10a.
[0081] In this way, by making the thickness of the cylindrical member 30 thinner towards the first surface 10a, it is possible to more easily alleviate the twisting distortion caused by the twisting of the porous body 40.
[0082] Therefore, even when the operating environment of the sample holder 1 becomes high temperature, cracks are less likely to occur in the porous body 40. Accordingly, as shown in the example in Figure 10, the gas flow inside the porous body 40 can be stabilized, making it possible to realize a sample holder 1 that does not easily lose its excellent heat uniformity.
[0083] Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above, and various modifications are possible without departing from the spirit thereof.
[0084] Further effects or other embodiments can be readily derived by those skilled in the art. Therefore, broader embodiments of this disclosure are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents.
[0085] Furthermore, this technology can also take the following configurations: (1) A sample holder comprising: a ceramic body having a sample holding surface and a first through-hole; a base plate supporting the ceramic body and having a second through-hole connected to the first through-hole; a cylindrical member located inside at least one of the first through-hole and the second through-hole and having a third through-hole connected to the first through-hole; and a porous body located inside the third through-hole, wherein the third through-hole has a first hole portion having an inner circumferential surface and a bottom surface, and a second hole portion connected to the bottom surface and having a smaller diameter than the first hole portion; the porous body is located in the first hole portion so as to be in contact with the bottom surface; and there is a gap between the inner circumferential surface and the bottom surface and the porous body that is larger than the diameter of the particles constituting the porous body. (2) The sample holder according to (1), wherein, when viewed in cross-section in the axial direction of the third through-hole, the first length, which is the length of the gap at the bottom surface, and the second length, which is the length of the gap at the inner circumferential surface, are less than 1 / 4 of the diameter of the porous body. (3) The sample holder according to (1) or (2) above, wherein the gap is annular. (4) The sample holder according to any one of (1) to (3) above, wherein the corner of the porous body constituting a part of the gap has an R shape. (5) The sample holder according to any one of (1) to (4) above, wherein when viewed in cross-section in the axial direction of the third through hole, the corner of the first hole where the bottom surface and the inner circumferential surface are in contact is obtuse. (6) The sample holder according to any one of (1) to (5) above, wherein the porous body is in point contact with the cylindrical member. (7) The sample holder according to (6) above, wherein glass is located in at least a part of the area where the porous body and the cylindrical member are in point contact. (8) The sample holder according to (7) above, wherein the main component of the glass located in the area where the porous body and the cylindrical member are in point contact is the same as the main component of the glass located at the grain boundary of the ceramic constituting the cylindrical member. (9) The sample holder according to any one of (1) to (8) above, wherein the main component of the porous body is the same as the main component of the cylindrical member.(10) The sample holder according to any one of (1) to (9) above, wherein the porous body has a diameter that increases toward the sample holding surface, and the cylindrical member has a wall thickness that decreases toward the sample holding surface.
[0086] 1 Sample holder 10 Ceramic body 10a First surface (an example of a sample holding surface) 11 First through hole 20 Base plate 21 Second through hole 30 Cylindrical member 31 Third through hole 31a First hole portion 31a1 Bottom surface 31a2 Inner surface 31a3 Corner portion 31b Second hole portion 40 Porous body 41 Corner portion 60 Gap D Diameter L1 First length L2 Second length P1-P5 Particles
Claims
1. A sample holder comprising: a ceramic body having a sample-holding surface and a first through-hole; a base plate supporting the ceramic body and having a second through-hole connected to the first through-hole; a cylindrical member located inside at least one of the first and second through-holes and having a third through-hole connected to the first through-hole; and a porous body located inside the third through-hole, wherein the third through-hole has a first hole portion having an inner circumferential surface and a bottom surface, and a second hole portion connected to the bottom surface and having a smaller diameter than the first hole portion; the porous body is located in the first hole portion so as to be in contact with the bottom surface; and there is a gap between the inner circumferential surface and the bottom surface and the porous body that is larger than the diameter of the particles constituting the porous body.
2. The sample holder according to claim 1, wherein, when viewed in cross-section in the axial direction of the third through-hole, the first length, which is the length of the gap at the bottom surface, and the second length, which is the length of the gap at the inner circumferential surface, are less than 1 / 4 of the diameter of the porous body.
3. The sample holder according to claim 1 or 2, wherein the gap is annular.
4. The sample holder according to any one of claims 1 to 3, wherein the corner of the porous body constituting a part of the gap has an R shape.
5. The sample holder according to any one of claims 1 to 4, wherein, when viewed in cross-section in the axial direction of the third through-hole, the corner of the first hole where the bottom surface and the inner circumferential surface meet is obtuse.
6. The sample holder according to any one of claims 1 to 5, wherein the porous body is in point contact with the cylindrical member.
7. The sample holder according to claim 6, wherein glass is located in at least a portion of the area where the porous body and the cylindrical member make point contact.
8. The sample holder according to claim 7, wherein the main component of the glass located at the point contact between the porous body and the cylindrical member is the same as the main component of the glass located at the grain boundaries of the ceramic constituting the cylindrical member.
9. The sample holder according to any one of claims 1 to 8, wherein the main component of the porous body is the same as the main component of the cylindrical member.
10. The sample holder according to any one of claims 1 to 9, wherein the porous body has a diameter that increases toward the sample holding surface, and the cylindrical member has a wall thickness that decreases toward the sample holding surface.