Sample holder

Abstract

This sample holder comprises a body, an internal electrode, and a via conductor. The body is composed of ceramic and has a holding surface for holding a sample. The internal electrode is positioned along the holding surface inside the body. The via conductor is electrically and mechanically connected to the internal electrode and extends in a direction intersecting the holding surface. A first portion of the internal electrode located near the via conductor has a higher silver concentration than a second portion of the internal electrode other than the first portion.

Description

Sample holder

[0001] SUMMARY OF THE INVENTION The disclosed embodiments relate to a sample holder.

[0002] In the process of manufacturing semiconductor components, sample holders are used to hold samples such as semiconductor wafers that are to be subjected to various processes. One known example of such a sample holder is one that includes a ceramic body and internal electrodes and via conductors located within the body. The internal electrodes are positioned along the holding surface of the body, and the via conductors extend in a direction that intersects with the holding surface.

[0003] JP 2016-051783 A

[0004] The sample holder of the present disclosure includes a main body, an internal electrode, and a via conductor. The main body is made of ceramic and has a holding surface that holds a sample. The internal electrode is located inside the main body along the holding surface. The via conductor is electrically and mechanically connected to the internal electrode and extends in a direction that intersects with the holding surface. Furthermore, a first portion of the internal electrode that is located near the via conductor has a higher silver concentration than a second portion of the internal electrode other than the first portion.

[0005] FIG. 1 is a cross-sectional view showing an example of the configuration of a sample holder according to an embodiment. FIG. 2 is an enlarged cross-sectional view showing an example of the configuration of a sample holder according to an embodiment. FIG. 3 is a planar perspective view and a cross-sectional view showing an example of the configuration of an internal electrode and a via conductor according to an embodiment. FIG. 4 is an enlarged cross-sectional view showing an example of the configuration of a sample holder according to Alternative Embodiment 1. FIG. 5 is an enlarged cross-sectional view showing an example of the configuration of a sample holder according to Alternative Embodiment 2. FIG. 6 is a planar perspective view and a cross-sectional view showing an example of the configuration of an internal electrode and a via conductor according to Alternative Embodiment 2. FIG. 7 is a planar perspective view and a cross-sectional view showing an example of the configuration of an internal electrode and a via conductor according to Alternative Embodiment 3. FIG. 8 is an enlarged cross-sectional view showing an example of the configuration of a sample holder according to Alternative Embodiment 4. FIG. 9 is a planar perspective view and a cross-sectional view showing an example of the configuration of an internal electrode and a via conductor according to Alternative Embodiment 4. FIG. 10 is an enlarged cross-sectional view showing an example of the configuration of a sample holder according to Alternative Embodiment 5. FIG. 11 is an enlarged cross-sectional view showing an example of the configuration of a sample holder according to Alternative Embodiment 6. FIG. 12 is an enlarged cross-sectional view showing an example of the configuration of a sample holder according to Alternative Embodiment 7.

[0006] Hereinafter, with reference to the accompanying drawings, various embodiments of the sample holder disclosed in the present application will be described. Note that the present disclosure is not limited to the various embodiments described below. Furthermore, various embodiments can be appropriately combined within the scope of not causing any contradiction in the processing content. Furthermore, the same components in the following various embodiments will be given the same reference numerals, and redundant explanations will be omitted.

[0007] In addition, in the following embodiments, expressions such as "parallel" and "perpendicular" may be used, but these expressions do not necessarily mean "parallel" or "perpendicular" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc.

[0008] In addition, in each of the drawings referred to below, for ease of understanding, an orthogonal coordinate system may be shown in which the X-axis, Y-axis, and Z-axis directions, which are perpendicular to each other, are defined, and the Z-axis direction is the thickness direction of the main body of the sample holder.

[0009] In the process of manufacturing semiconductor components, sample holders are used to hold samples such as semiconductor wafers that are to be subjected to various processes. One known example of such a sample holder is one that includes a ceramic body and internal electrodes and via conductors located within the body. The internal electrodes are positioned along the holding surface of the body, and the via conductors extend in a direction that intersects with the holding surface.

[0010] However, in the above-mentioned conventional technology, the electrical resistance at the interface between the internal electrode and the via conductor is relatively high, which makes Joule heat more likely to be generated at this interface, and this localized heat generation may reduce the thermal uniformity of the entire sample holder.

[0011] Therefore, there is a need to develop a technology that can solve the above problems and improve the temperature uniformity of the sample holder.

[0012] <Embodiment> First, the configuration of a sample holder 1 according to an embodiment will be described with reference to Figures 1 to 3. Figure 1 is a cross-sectional view showing an example of the configuration of a sample holder 1 according to an embodiment. As shown in Figure 1, the sample holder 1 according to the embodiment may include a main body 10, an internal electrode 20, a via conductor 30, and an external electrode 40. The sizes of these components may be similar to those of conventionally known sample holders, for example.

[0013] The main body 10 may be made of ceramic. The main body 10 may be made by molding a ceramic-containing raw material into a flat plate shape, for example, a disk shape. The main body 10 may be made of, for example, aluminum oxide (Al ２ O ３ ), aluminum nitride (AlN), or yttria (Y ２ O ３ ) may be contained as a main component.

[0014] The main body 10 may have, for example, a holding surface 10a and a back surface 10b. The holding surface 10a may be a surface for holding a sample A such as a semiconductor wafer. The back surface 10b may be located on the opposite side to the holding surface 10a.

[0015] The internal electrode 20 may be located inside the main body 10. For example, the internal electrode 20 may be located along the holding surface 10a of the main body 10 (for example, parallel to the holding surface 10a). Note that in the present disclosure, the internal electrode 20 is not limited to being located inside the main body 10, and may be partially exposed from the main body 10, for example.

[0016] The internal electrode 20 may include, for example, an attraction electrode 21, a connection electrode 22, and a heater electrode 23. The attraction electrode 21 may be located closer to the holding surface 10a than the connection electrode 22 and the heater electrode 23, and may function as an electrode that electrostatically attracts the sample A to the holding surface 10a.

[0017] The connection electrode 22 may be located, for example, between the chucking electrode 21 and the external electrode 40 and function as part of the wiring that electrically connects the chucking electrode 21 and the external electrode 40 .

[0018] The heater electrode 23 may be configured, for example, as a resistance heating element that generates heat when a voltage is applied, and may function as a heater that heats the sample A held on the holding surface 10a.

[0019] Of the internal electrodes 20, the attraction electrode 21 and the connection electrode 22 may be made of a conductor whose main component is a metal such as platinum (Pt), tungsten (W), or molybdenum (Mo). The heater electrode 23 may be made of a heating resistor whose main component is a metal such as tungsten, molybdenum, platinum, or rhenium (Re).

[0020] The sample holder 1 of the present disclosure is not limited to including the suction electrode 21, the connection electrode 22, and the heater electrode 23 as the internal electrode 20, but may include some of these electrodes, or may further include a wide variety of internal electrodes.

[0021] The via conductors 30 may be electrically and mechanically connected to the internal electrodes 20. The via conductors 30 may extend in a direction intersecting the holding surface 10a of the main body 10 (for example, perpendicular to the holding surface 10a). The via conductors 30 may be made of a conductor containing, as a main component, a metal such as molybdenum, platinum, or tungsten.

[0022] The via conductor 30 may include, for example, a first via conductor 31, a second via conductor 32, and a third via conductor 33. The first via conductor 31 may electrically connect the chucking electrode 21 and the connection electrode 22, for example.

[0023] The second via conductor 32 may, for example, electrically connect the connection electrode 22 and the external electrode 40. The third via conductor 33 may, for example, electrically connect the heater electrode 23 and the external electrode 40.

[0024] The external electrode 40 may be located so as to be exposed from at least a portion of the main body 10. The external electrode 40 may be located so as to be exposed at least a portion of the back surface 10b of the main body 10, for example.

[0025] The external electrode 40 may include, for example, a first external electrode 41 and a second external electrode 42. The first external electrode 41 may be electrically and mechanically connected to, for example, the second via conductor 32. The second external electrode 42 may be electrically and mechanically connected to, for example, the third via conductor 33.

[0026] A power supply terminal T may be electrically and mechanically connected to the external electrode 40 via solder S. In an embodiment, a predetermined power may be supplied to the external electrode 40 from an external power source (not shown) via the power supply terminal T. The external electrode 40 may be made of a conductor containing, as a main component, a metal such as molybdenum, platinum, or tungsten.

[0027] Fig. 2 is an enlarged cross-sectional view showing an example of the configuration of the sample holder 1 according to the embodiment, and is an enlarged view of a region R shown in Fig. 1. Fig. 3 is a plan perspective view (Fig. 3(a)) and a cross-sectional view (Fig. 3(b)) showing an example of the configuration of an internal electrode 20 and a via conductor 30 according to the embodiment.

[0028] 2 , in the sample holder 1 according to the embodiment, the internal electrode 20, for example, the connection electrode 22, may have a first portion 20a and a second portion 20b. The first portion 20a may be located near the via conductor 30 in the internal electrode 20. Here, “near” refers to a region that overlaps with at least the via conductor 30 in a planar perspective view looking toward the holding surface 10a, and may hereinafter be referred to as “nearby.” The second portion 20b may be located at a location in the internal electrode 20 other than the first portion 20a.

[0029] 2, the connection electrode 22 may have the first portion 20a in the vicinity of the second via conductor 32. In addition, in the example of FIG. 2, the connection electrode 22 may have the second portion 20b in a location other than the vicinity of the second via conductor 32.

[0030] 3A, the first portion 20a according to the embodiment may have substantially the same size as the adjacent via conductors 30 in a planar perspective view. Also, as shown in FIG. 3B, the first portion 20a according to the embodiment may have a rectangular shape in a cross-sectional view.

[0031] In the embodiment, the first portion 20a located near the via conductor 30 may have a higher silver concentration than the second portion 20b. In this way, the first portion 20a contains a large amount of silver, which has good electrical conductivity, thereby reducing the electrical resistance at the interface between the internal electrode 20 where the first portion 20a is located and the via conductor 30, thereby reducing local heat generation at this interface. Note that the second portion 20b may have a lower silver concentration than the first portion 20a, but may not contain silver.

[0032] In addition, since the first portion 20a, which has a high concentration of silver, also has a high thermal conductivity, even if heat is generated at the interface between the internal electrode 20 and the via conductor 30, the heat generated at this interface can be quickly dissipated.

[0033] Therefore, according to the embodiment, the temperature uniformity of the sample holder 1 can be improved.

[0034] Furthermore, in the embodiment, since the first portion 20a contains a large amount of silver, which is softer than platinum and tungsten, the stress caused by thermal expansion and thermal contraction at the interface between the internal electrode 20 and the via conductor 30 can be alleviated.

[0035] In an embodiment, the concentration of silver contained in each portion can be determined by, for example, WDS (wavelength dispersive X-ray spectroscopy) mapping, TOF-SIMS (time-of-flight secondary ion mass spectroscopy) mapping, EDS (energy dispersive X-ray spectroscopy) mapping, etc. The difference in silver concentration can be confirmed by the difference in color tone.

[0036] The first portion 20 a and the second portion 20 b according to the embodiment may be formed, for example, as follows: First, a ceramic green sheet for forming the main body 10 is prepared. A paste-like conductive material for forming the via conductors 30 may be embedded in the ceramic green sheet.

[0037] Next, a paste-like conductive material for forming the entire internal electrode 20 is printed on the surface of the ceramic green sheet by a known screen printing method or the like.

[0038] Next, a silver-rich conductive paste material for forming the first portion 20a is applied on the surface of the printed conductive paste material by a known screen printing method or the like.

[0039] Next, the ceramic green sheets coated with the paste-like conductive material as described above and the ceramic green sheets not printed with the paste-like conductive material are stacked together so that an internal electrode 20 is formed at a predetermined internal position in the sample holder 1.

[0040] In addition, a paste-like conductive material for forming via conductors 30 may be embedded in the ceramic green sheets on which the paste-like conductive material is not printed.

[0041] Finally, the obtained laminate is fired at a predetermined temperature in a predetermined atmosphere to produce the sample holder 1 having therein the internal electrode 20 including the first portion 20a and the second portion 20b.

[0042] The method of forming the first portion 20a is not limited to the above-described case of applying a silver-rich paste-like conductive material over the surface of the paste-like conductive material used to form the entire internal electrode 20.

[0043] For example, a paste-like conductive material for forming the second portion 20b of the internal electrode 20 may be screen-printed, and a paste-like conductive material containing a large amount of silver for forming the first portion 20a may be separately screen-printed.

[0044] In the embodiment, the via conductor 30 (here, the second via conductor 32) in contact with the first portion 20a may have a higher silver concentration than the first portion 20a, thereby reducing the electrical resistance of the via conductor 30 and thereby reducing heat generation inside the via conductor 30.

[0045] Therefore, according to the embodiment, the temperature uniformity of the sample holder 1 can be improved.

[0046] In this case, the first portion 20a having a high silver concentration may be formed in the internal electrode 20 by diffusing silver atoms from the via conductor 30 having a high silver concentration into the internal electrode 20.

[0047] Specifically, when embedding a paste-like conductive material for forming the via conductors 30 in the ceramic green sheets, it is preferable to use a paste-like conductive material that contains a large amount of silver, which allows the via conductors 30 and the first portions 20a containing a large amount of silver to be formed simultaneously.

[0048] In addition, in an embodiment, the second via conductor 32 in contact with the first portion 20a may have a higher silver concentration than the first portion 20a, and the external electrode 40 in contact with the second via conductor 32 may have a higher silver concentration than the second via conductor 32.

[0049] This allows the external electrode 40, to which power is supplied from outside, to have a lower electrical resistance than the second via conductor 32 and the first portion 20a of the internal electrode 20, making it easier to control the temperature distribution when applying voltage to the suction electrode 21.

[0050] In this case, the first portion 20 a having a high silver concentration may be formed in the internal electrode 20 by diffusing silver atoms from the external electrode 40 having a high silver concentration into the internal electrode 20 through the via conductor 30 .

[0051] Specifically, it is preferable to use a paste-like conductive material containing a large amount of silver when embedding the paste-like conductive material in the ceramic green sheets to form the via conductors 30. Furthermore, it is preferable to use a paste-like conductive material containing an even larger amount of silver when screen-printing the paste-like conductive material in the ceramic green sheets to form the external electrodes 40.

[0052] This allows the external electrodes 40 containing a large amount of silver, the via conductors 30, and the first portions 20a to be formed all at once.

[0053] In addition, in the embodiment, the external electrode 40 and the power supply terminal T may be joined with solder S. By joining the external electrode 40 and the power supply terminal T with solder S, which has lower electrical resistance than a conductive adhesive or the like, it is possible to reduce local heat generation between the external electrode 40 and the power supply terminal T.

[0054] Therefore, according to the embodiment, the temperature uniformity of the sample holder 1 can be further improved.

[0055] <Another embodiment 1> Next, the configuration of the sample holder 1 according to various other embodiments will be described with reference to Fig. 4 to Fig. 12. Fig. 4 is an enlarged cross-sectional view showing an example of the configuration of the sample holder 1 according to another embodiment 1.

[0056] 4, in another embodiment 1, the configuration of the chucking electrode 21 is different from that of the above-described embodiment. Specifically, in another embodiment 1, in addition to the connection electrode 22, the chucking electrode 21 may also have a first portion 20a and a second portion 20b.

[0057] 4, the chucking electrode 21 may have the first portion 20a in the vicinity of the first via conductor 31. Also, in the example of FIG. 4, the chucking electrode 21 may have the second portion 20b in a location other than the vicinity of the first via conductor 31.

[0058] This reduces the electrical resistance at the interface between the chucking electrode 21 where the first portion 20a is located and the first via conductor 31, thereby reducing local heat generation at this interface.

[0059] Furthermore, since the first portion 20a, which has a high concentration of silver, also has a high thermal conductivity, even if heat is generated at the interface between the chucking electrode 21 and the first via conductor 31, the heat generated at this interface can be quickly dissipated.

[0060] Therefore, according to the alternative embodiment 1, the temperature uniformity of the sample holder 1 can be improved.

[0061] Furthermore, in another embodiment 1, the first portion 20a contains a large amount of silver, which is softer than platinum, tungsten, etc., and therefore, stress caused by thermal expansion and thermal contraction at the interface between the chucking electrode 21 and the first via conductor 31 can be alleviated.

[0062] <Other Embodiments 2 and 3> Fig. 5 is an enlarged cross-sectional view showing an example of the configuration of a sample holder 1 according to another embodiment 2. Fig. 6 is a plan perspective view (Fig. 6(a)) and a cross-sectional view (Fig. 6(b)) showing an example of the configuration of an internal electrode 20 and a via conductor 30 according to another embodiment 2.

[0063] 5 and 6, in Alternative Embodiment 2, the configuration of the first portion 20a is different from that of the above-described Alternative Embodiment 1. Specifically, in Alternative Embodiment 2, the first portion 20a may be larger in size than the via conductor 30 in a planar perspective view, as shown in (a) of FIG.

[0064] This further reduces the electrical resistance at the interface between the internal electrode 20 where the first portion 20a is located and the via conductor 30, thereby further reducing local heat generation at this interface.

[0065] In addition, since the thermal conductivity is also high in the first portion 20a, which has a high concentration of silver, even if heat is generated at the interface between the internal electrode 20 and the via conductor 30, the heat generated at this interface can be dissipated even more quickly.

[0066] Therefore, according to the second alternative embodiment, the temperature uniformity of the sample holder 1 can be further improved.

[0067] In the present disclosure, the planar shape and cross-sectional shape of the first portion 20a are not limited to the example shown in Fig. 6. Fig. 7 is a plan perspective view and a cross-sectional view showing an example of the configuration of an internal electrode 20 and a via conductor 30 according to another embodiment 3.

[0068] As shown in FIG. 7A, in another embodiment 3, the first portion 20a may be larger than the via conductor 30 in plan view and may be concentric with the via conductor 30.

[0069] As a result, the heat generating portion is located on the outer periphery of the first portion 20a near the interface between the internal electrode 20 and the via conductor 30, and the heat generating portion can be dispersed in a ring shape. Therefore, according to another embodiment 3, it is possible to make it difficult for stress to be applied from the internal electrode 20 to the via conductor 30.

[0070] In another embodiment 3, as shown in FIG. 7B, the first portion 20a may have a trapezoidal shape in cross section that is wider on the via conductor 30 side.

[0071] This allows the heat generated at the interface between the internal electrode 20 and the via conductor 30 to be dissipated over a wider area, even if the heat is generated at the interface between the internal electrode 20 and the via conductor 30. Therefore, according to another embodiment 3, the thermal uniformity of the sample holder 1 can be further improved.

[0072] <Alternative Embodiment 4> Fig. 8 is an enlarged cross-sectional view showing an example of the configuration of a sample holder 1 according to alternative embodiment 4. Fig. 9 is a plan perspective view (Fig. 9(a)) and a cross-sectional view (Fig. 9(b)) showing an example of the configuration of an internal electrode 20 and a via conductor 30 according to alternative embodiment 4.

[0073] 8 and 9, in Alternative Embodiment 4, the configuration of the via conductor 30 is different from that in Alternative Embodiment 2. Specifically, in Alternative Embodiment 4, the via conductor 30 may have a first end portion 30a and a central portion 30b.

[0074] The first end portion 30a is the end portion of the via conductor 30 that is in contact with the first portion 20a of the internal electrode 20. The central portion 30b is the center portion in the extension direction (Z-axis direction) of the via conductor 30. More specifically, when the length of the via conductor 30 in the Z-axis direction is divided into thirds, the first end portion 30a is closest to the first portion 20a, and the central portion 30b follows this.

[0075] In another embodiment 4, the first end 30a of the via conductor 30 may have a higher silver concentration than the central portion 30b, which further reduces the electrical resistance at the interface between the internal electrode 20 where the first portion 20a is located and the via conductor 30 where the first end 30a is located, thereby further reducing local heat generation at this interface.

[0076] In addition, since the thermal conductivity is also high at the first end 30a, which has a high concentration of silver, even if heat is generated at the interface between the internal electrode 20 and the via conductor 30, the heat generated at this interface can be dissipated even more quickly.

[0077] Therefore, according to the fourth alternative embodiment, the temperature uniformity of the sample holder 1 can be further improved.

[0078] <Another embodiment 5> Fig. 10 is an enlarged cross-sectional view showing an example of the configuration of the sample holder 1 according to another embodiment 5. As shown in Fig. 10, in another embodiment 5, the configurations of the connection electrodes 22 and the first via conductors 31 are different from those of the above-described another embodiment 4.

[0079] Specifically, in another embodiment 5, the connection electrode 22 may also have the first portion 20a in the vicinity of the first via conductor 31. Furthermore, in another embodiment 5, the first via conductor 31 may also have the first end 30a at the end on the side of the first portion 20a located at the connection electrode 22.

[0080] This reduces the electrical resistance at the interface between the connection electrode 22 where the first portion 20a is located and the first via conductor 31 where the first end 30a is located, thereby reducing local heat generation at this interface.

[0081] In addition, since the thermal conductivity is also high in the first portion 20a and the first end portion 30a, which have a high concentration of silver, even if heat is generated at the interface between the connection electrode 22 and the first via conductor 31, the heat generated at this interface can be quickly dissipated.

[0082] Therefore, according to the fifth alternative embodiment, the temperature uniformity of the sample holder 1 can be improved.

[0083] In another embodiment 5, the first portion 20a of the connection electrode 22 located near the first via conductor 31 may be larger in size than the first via conductor 31 in a planar perspective view.

[0084] This further reduces the electrical resistance at the interface between the connection electrode 22 where the first portion 20a is located and the first via conductor 31, thereby further reducing local heat generation at this interface.

[0085] In addition, since the thermal conductivity is also high in the first portion 20a, which has a high concentration of silver, even if heat is generated at the interface between the connection electrode 22 and the first via conductor 31, the heat generated at this interface can be dissipated even more quickly.

[0086] Therefore, according to the fifth alternative embodiment, the temperature uniformity of the sample holder 1 can be further improved.

[0087] <Alternative Embodiment 6> Fig. 11 is an enlarged cross-sectional view showing an example of the configuration of the sample holder 1 according to alternative embodiment 6. As shown in Fig. 11, alternative embodiment 6 differs from alternative embodiment 5 in the configuration of the second via conductors 32.

[0088] Specifically, in another embodiment 6, the second via conductor 32 may have a first end 30a, a central portion 30b, and a second end 30c. The second end 30c is the end of the via conductor 30 that is in contact with the external electrode 40. More specifically, when the length of the via conductor 30 in the Z-axis direction is divided into thirds, the first end 30a is closest to the first region 20a, followed by the central portion 30b, and the second end 30c is next and closest to the external electrode 40.

[0089] In another embodiment 6, the second end 30c of the via conductor 30 may have a higher silver concentration than the central portion 30b, thereby further reducing the electrical resistance at the interface between the external electrode 40 and the via conductor 30 where the second end 30c is located, thereby further reducing local heat generation at this interface.

[0090] In addition, since the thermal conductivity is also high at the second end 30c, which has a high concentration of silver, even if heat is generated at the interface between the external electrode 40 and the via conductor 30, the heat generated at this interface can be dissipated even more quickly.

[0091] Therefore, according to the sixth alternative embodiment, the temperature uniformity of the sample holder 1 can be further improved.

[0092] <Another embodiment 7> Fig. 12 is an enlarged cross-sectional view showing an example of the configuration of the sample holder 1 according to another embodiment 7. As shown in Fig. 12, in another embodiment 7, the configuration of the external electrode 40 and the like differs from that of the above-mentioned another embodiment 5.

[0093] Specifically, in another embodiment 7, a recess 10c may be provided on the rear surface 10b of the main body 10. This recess 10c may have a depth that reaches the connection electrode 22, for example. In other words, a portion of the connection electrode 22 may be exposed on the inner wall of the recess 10c.

[0094] In another embodiment 7, an external electrode 40 may be located along the inner wall of the recess 10 c. The external electrode 40 may be electrically and mechanically connected to the connection electrode 22 exposed on the inner wall of the recess 10 c.

[0095] Even with such a configuration of the external electrode 40, the first portion 20a of the internal electrode 20 has a higher silver concentration than the second portion 20b, thereby reducing local heat generation at the interface between the internal electrode 20 and the via conductor 30.

[0096] In addition, since the first portion 20a, which has a high concentration of silver, also has a high thermal conductivity, even if heat is generated at the interface between the internal electrode 20 and the via conductor 30, the heat generated at this interface can be quickly dissipated.

[0097] Therefore, according to the seventh embodiment, the temperature uniformity of the sample holder 1 can be improved.

[0098] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0099] Further advantages and other aspects may readily occur to those skilled in the art. Therefore, the disclosure in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

[0100] The present technology can also be configured as follows. (1) A sample holder comprising: a main body made of ceramic and having a holding surface for holding a sample; an internal electrode located inside the main body along the holding surface; and a via conductor electrically and mechanically connected to the internal electrode and extending in a direction intersecting the holding surface, wherein a first portion of the internal electrode located near the via conductor has a higher silver concentration than a second portion of the internal electrode other than the first portion. (2) The sample holder according to (1), wherein the first portion is larger in size than the via conductor in a planar perspective view. (3) The sample holder according to (1) or (2), wherein a first end of the via conductor on the side contacting the internal electrode has a higher silver concentration than a central portion of the via conductor. (4) The sample holder according to any one of (1) to (3), further comprising an external electrode electrically and mechanically connected to a power supply terminal, wherein the via conductor is electrically and mechanically connected to the external electrode, and wherein a second end of the via conductor that contacts the external electrode has a higher silver concentration than a central portion of the via conductor. (5) The sample holder according to any one of (1) to (4), wherein the via conductor has a higher silver concentration than the first portion of the internal electrode. (6) The sample holder according to (5), further comprising an external electrode electrically and mechanically connected to a power supply terminal, wherein the external electrode has a higher silver concentration than the via conductor.

[0101] REFERENCE SIGNS LIST 1 sample holder 10 main body 10a holding surface 20 internal electrode 20a first portion 20b second portion 30 via conductor 30a first end portion 30b central portion 30c second end portion 40 external electrode A sample S solder T power supply terminal

Claims

1. A sample holder comprising: a main body made of ceramic and having a holding surface for holding a sample; an internal electrode located inside the main body along the holding surface; and via conductors electrically and mechanically connected to the internal electrode and extending in a direction intersecting the holding surface, wherein a first portion of the internal electrode located near the via conductor has a higher silver concentration than a second portion of the internal electrode other than the first portion.

2. A sample holder according to claim 1, wherein the first portion is larger in size than the via conductor in plan view.

3. A sample holder according to claim 1 or 2, wherein the via conductor has a first end portion on the side in contact with the internal electrode that has a higher silver concentration than the central portion of the via conductor.

4. A sample holder according to any one of claims 1 to 3, further comprising an external electrode electrically and mechanically connected to a power supply terminal, wherein the via conductor is electrically and mechanically connected to the external electrode, and wherein the second end of the via conductor, which is in contact with the external electrode, has a higher silver concentration than the central portion of the via conductor.

5. A sample holder according to any one of claims 1 to 4, wherein the via conductor has a higher silver concentration than the first portion of the internal electrode.

6. A sample holder according to claim 5, further comprising an external electrode electrically and mechanically connected to the power supply terminal, said external electrode having a higher silver concentration than said via conductor.

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