Sample holder

Abstract

A sample holder according to the present disclosure has a ceramic substrate, an internal electrode, a metal terminal, and a cylindrical section. The ceramic substrate has a first surface and a second surface positioned opposite to the first surface. The internal electrode is located inside the ceramic substrate. The metal terminal has a first shaft section and a first flange section located at an end of the first shaft section and projecting from the first shaft section. The first flange section is in contact with the first surface. The cylindrical section comprises a third surface in contact with the first surface, a fourth surface positioned opposite to the third surface, and a first through-hole penetrating the third surface and the fourth surface, and surrounds the metal terminal. The first through-hole comprises a first portion that surrounds the first shaft section, and a second portion that expands in diameter from the first portion toward the third surface and covers the first flange section.

Description

Sample holder

[0001] The present disclosure relates to a sample holder.

[0002] A sample holder has been known that includes a ceramic substrate having an internal electrode, an electrode pin located on the back surface of the ceramic substrate and connected to the internal electrode, and a shielding tube located on the back surface of the ceramic substrate and surrounding the electrode pin. The electrode pin has a flange-shaped contact portion that makes contact with the back surface of the ceramic substrate.

[0003] JP 2016-051783 A

[0004] A sample holder according to one embodiment of the present disclosure includes a ceramic substrate, an internal electrode, a metal terminal, and a cylindrical portion. The ceramic substrate has a first surface and a second surface opposite the first surface. The internal electrode is located inside the ceramic substrate. The metal terminal has a first axial portion and a first flange portion located at an end of the first end and extending from the first axial portion. The first flange portion contacts the first surface. The cylindrical portion has a third surface contacting the first surface, a fourth surface opposite the third surface, and a first through hole penetrating the third and fourth surfaces, surrounding the metal terminal. The first through hole has a first portion surrounding the first axial portion and a second portion expanding in diameter from the first portion toward the third surface and covering the first flange portion.

[0005] FIG. 1 is a cross-sectional view showing an example of the configuration of a sample holder according to the first embodiment. FIG. 2 is a schematic enlarged view showing the configuration of portion H1 shown in FIG. 1. FIG. 3 is a schematic enlarged view showing the configuration of portion H1 in a sample holder according to the second embodiment. FIG. 4 is a schematic enlarged view showing the configuration of portion H1 in a sample holder according to the third embodiment. FIG. 5 is a schematic enlarged view showing the configuration of portion H1 in a sample holder according to the fourth embodiment. FIG. 6 is a schematic enlarged view showing the configuration of portion H1 in a sample holder according to the fifth embodiment. FIG. 7 is a schematic enlarged view showing the configuration of portion H1 in a sample holder according to the fifth embodiment. FIG. 8 is a schematic enlarged view showing the configuration of portion H1 in a sample holder according to the sixth embodiment. FIG. 9 is a schematic enlarged view showing the configuration of portion H1 in a sample holder according to the sixth embodiment. FIG. 10 is a schematic enlarged view showing the configuration of portion H1 in a sample holder according to the sixth embodiment. FIG. 11 is a schematic enlarged view showing the configuration of portion H1 in a sample holder according to the sixth embodiment. Fig. 12 is a schematic enlarged view showing the configuration of the second shaft portion of the metal terminal according to the seventh embodiment. Fig. 13 is a schematic enlarged view showing the configuration of the H1 portion of the sample holder according to the eighth embodiment.

[0006] Hereinafter, a mode for carrying out a sample holder according to the present disclosure (hereinafter referred to as an "embodiment") will be described in detail with reference to the drawings. Note that the present disclosure is not limited to this embodiment. Furthermore, each embodiment can be appropriately combined within the scope of not causing any contradiction in the processing content. Furthermore, the same parts in each of the following embodiments will be given the same reference numerals, and duplicated explanations will be omitted.

[0007] In addition, in 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 sample holder.

[0008] In the above-mentioned conventional technology, heat from the ceramic substrate dissipates through the flange-like contacts on the electrode pins, which can cause localized drops in the temperature of the sample support surface. As such, the conventional technology leaves room for improvement in terms of improving the temperature uniformity of the sample support surface.

[0009] First Embodiment Fig. 1 is a cross-sectional view showing an example of the configuration of a sample holder 100 according to the first embodiment. Fig. 2 is a schematic enlarged view showing the configuration of part H1 shown in Fig. 1. Note that Fig. 1 shows components that are mainly necessary for explaining the sample holder, and other components are omitted as appropriate. For example, fixing jigs and the like that make up the sample holder are not shown. Furthermore, the dimensions of the sample holder in Fig. 1 are shown by enlarging the elements necessary for explaining the sample holder.

[0010] 1, the sample holder 100 according to the first embodiment includes a ceramic substrate 1, an internal electrode 2, a metal terminal 3, a cylindrical portion 4, a heat-resistant member 8, and a base plate 9. The sample holder 100 is, for example, an electrostatic chuck that attracts and holds a sample such as a semiconductor wafer by utilizing electrostatic force.

[0011] The ceramic substrate 1 has a first surface 11, a second surface 12 located opposite the first surface 11, and a hole 13 opening into the first surface 11. The depth of the hole 13 reaches the internal electrode 2. The diameter of the hole 13 is larger than a second axial portion 32 (described later) of the metal terminal 3. In FIG. 1, the second surface 12 is a surface for holding a sample. The ceramic substrate 1 has, for example, a circular shape in a plan view. In FIG. 1, the hole 13 penetrates upward from the internal electrode 2, but it may also be located at the same height as the internal electrode 2.

[0012] The ceramic substrate 1 may contain, for example, aluminum oxide, aluminum nitride, yttria, cordierite, silicon carbide, or silicon nitride as a main component. The ceramic substrate 1 is obtained, for example, by stacking and firing a plurality of green sheets. Note that in the following description of each embodiment, it is assumed that the ceramic substrate 1 contains aluminum nitride as a main component.

[0013] An internal electrode 2 is located inside the ceramic substrate 1. Specifically, the internal electrode 2 may include, for example, a first electrode 21 that is a heating resistor and a second electrode 22 that is an electrostatic attraction internal electrode.

[0014] The internal electrodes 2 are made of a metal material, such as tungsten, molybdenum, rhenium, alloys thereof, or platinum.

[0015] The metal terminal 3 is electrically connected to the internal electrode 2. In the example shown in Fig. 1, the sample holder 100 has two metal terminals 3. One metal terminal 3 is electrically connected to the first electrode 21, and the other metal terminal 3 is electrically connected to the second electrode 22. The number of metal terminals 3 provided in the sample holder 100 is not limited to the example shown in Fig. 1. For example, the sample holder 100 may have three or more metal terminals 3.

[0016] The metal terminal 3 is a terminal made of metal and has a first shank 31, a first flange 34, and a second shank 32. The first shank 31 and the second shank 32 extend along the thickness direction of the ceramic substrate 1 (here, the Z-axis direction). The first shank 31 is located outside the ceramic substrate 1. The second shank 32 is located inside the ceramic substrate 1. In other words, of the shanks of the metal terminal 3, the portion located outside the ceramic substrate 1 corresponds to the first shank 31, and the portion located inside the ceramic substrate 1 corresponds to the second shank 32. The second shank 32 is inserted into a hole 13 in the ceramic substrate 1.

[0017] 1 , the hole 13 may have a space above the metal terminal 3. This reduces stress that occurs when the thermally expanded metal terminal 3 comes into contact with the ceramic substrate 1 during heating. Furthermore, even when the metal terminal 3 is composed of the first shank 31 and the first flange 34, i.e., when the metal terminal 3 does not have the second shank 32, electrical connection between the internal electrode 2 and the metal terminal 3 can be achieved by providing a metal layer on the inner surface of the hole 13 instead of the second shank 32.

[0018] The first flange portion 34 is located at the end of the first shaft portion 31 on the ceramic substrate 1 side, and protrudes from the first shaft portion 31. The first flange portion 34 contacts the first surface 11 of the ceramic substrate 1. The second shaft portion 32 is electrically connected to the first electrode 21 inside the ceramic substrate 1.

[0019] The cylindrical portion 4 is a cylindrical member that surrounds the metal terminal 3. Specifically, the cylindrical portion 4 has a third surface 41, a fourth surface 42 located on the opposite side of the third surface, and a first through hole 43 that penetrates the third surface 41 and the fourth surface 42. The cylindrical portion 4 contacts the first surface 11 of the ceramic substrate 1 at the third surface 41. The cylindrical portion 4 also surrounds the metal terminal 3 at the first through hole 43.

[0020] The cylindrical portion 4 has insulating properties. The insulating material of the cylindrical portion 4 may be, for example, ceramic. An example of the ceramic used for the cylindrical portion 4 is mullite. Note that the material of the cylindrical portion 4 is not limited to mullite, and may be, for example, aluminum nitride.

[0021] The ceramic substrate 1 is primarily composed of aluminum nitride. When the temperature of the sample holder 100 increases, stress occurs at the contact surface between the ceramic substrate 1 and the cylindrical portion 4 due to the difference in thermal expansion coefficient between the ceramic substrate 1 and the cylindrical portion 4. By using aluminum nitride or mullite, which has a thermal expansion coefficient relatively close to that of aluminum nitride, as the primary component of the cylindrical portion 4, stress occurring at the contact surface between the ceramic substrate 1 and the cylindrical portion 4 can be reduced. Therefore, the sample holder 100 having such a configuration is highly durable. Furthermore, compared to other ceramic materials, the thermal conductivity of aluminum nitride and mullite is relatively low. Therefore, a cylindrical portion 4 primarily composed of aluminum nitride or mullite is more effective at retaining the temperature of the first flange portion 34, thereby further reducing the deterioration of temperature uniformity in the sample holder 100.

[0022] The material of the cylindrical portion 4 is not limited to ceramic, but may be, for example, resin.

[0023] As shown in FIG. 2 , the first through hole 43 has a first portion 431 and a second portion 432. The first portion 431 is a portion of the first through hole 43 that surrounds the first shaft portion 31 of the metal terminal 3. The second portion 432 is a portion of the first through hole 43 that covers the first flange portion 34. Specifically, the second portion 432 is a portion that expands in diameter from the first portion 431 toward the third surface 41 and covers the first flange portion 34. Here, "covering the first flange portion 34" means that, when the surface of the first flange portion 34 facing the first surface 11 is defined as the "first flange surface" and the surface opposite the first flange surface is defined as the "second flange surface," the second portion 432 not only has a surface facing the outer peripheral surface of the first flange portion 34 but also a surface facing the second flange surface. In other words, the second portion 432 covers the first flange portion 34 from the outer peripheral surface of the first flange portion 34 to the second flange surface. The second portion 432 only needs to cover at least a portion of the second flange surface.

[0024] The thermal conductivity of the metal terminal 3 is higher than that of the ceramic substrate 1. Therefore, the heat of the ceramic substrate 1 passes through the metal terminal 3 and dissipates as radiant heat from the surface of the metal terminal 3. This may reduce the temperature uniformity of the sample holder 100. In particular, because the first flange portion 34 of the metal terminal 3 is in contact with the ceramic substrate 1 over a wide area, the heat of the ceramic substrate 1 is likely to dissipate from the first flange portion 34.

[0025] In contrast, the sample holder 100 according to the embodiment has a second portion 432 that covers the first flange portion 34 in the first through-hole 43 of the cylindrical portion 4. With this configuration, the second portion 432 can receive more radiant heat from the first flange portion 34 than when the cylindrical portion 4 does not have the second portion 432, for example, when the cylindrical portion 4 has a cylindrical first through-hole 43 that is formed with a diameter larger than the diameter of the first flange portion 34 from the third surface 41 to the fourth surface 42. As a result, the second portion 432 is heated, thereby keeping the first flange portion 34 located in the internal space of the second portion 432 warm.

[0026] Furthermore, the space of the first through-hole 43 narrows from the second portion 432 toward the first portion 431. Therefore, the heated air located in the internal space of the second portion 432 is less likely to escape from the internal space of the second portion 432, and the first flange portion 34 is more likely to be kept warm.

[0027] Thus, according to the sample holder 100 of the embodiment, heat is less likely to dissipate from the first flange portion 34 to the outside of the sample holder 100, so that the deterioration of the temperature uniformity of the sample holder 100 can be reduced.

[0028] In Fig. 1 , one cylindrical portion 4 surrounds one metal terminal 3, but the number of metal terminals 3 surrounded by one cylindrical portion 4 is not limited to the example in Fig. 1 . The cylindrical portion 4 may surround multiple metal terminals 3. Also, in Fig. 1 , the cylindrical portion 4 has a circular cross section when viewed from above in the thickness direction of the ceramic substrate 1, but the cross-sectional shape is not limited to a circular shape and may be an elliptical shape or a polygonal shape. For example, the cylindrical portion 4 may have two first through holes 43 therein, and a metal terminal 3 may be inserted into each of the first through holes 43, and may have an elliptical cross section when viewed from above in the thickness direction of the ceramic substrate 1.

[0029] The heat-resistant member 8 is located between the ceramic substrate 1 and a base plate 9 (described later). Specifically, the heat-resistant member 8 has a fifth surface 81 in contact with the first surface 11 of the ceramic substrate 1, a sixth surface 82 located on the opposite side of the fifth surface, and a second through hole 83 passing through the fifth surface 81 and the sixth surface 82. The heat-resistant member 8 surrounds the cylindrical portion 4 at the second through hole 83.

[0030] The heat-resistant member 8 has heat resistance and a lower thermal expansion coefficient than the ceramic substrate 1. Because the thermal expansion coefficient of the heat-resistant member 8 is lower than that of the ceramic substrate 1, deformation of the heat-resistant member 8 due to temperature differences in the thickness direction of the heat-resistant member 8 can be reduced even when the heat-resistant member 8 is heated to, for example, 300°C or higher. The heat-resistant member 8 may be, for example, cordierite. The heat-resistant member 8 is not limited to cordierite, and may be, for example, glass. Furthermore, when the ceramic substrate 1 is used at temperatures below 300°C, the thickness of the ceramic substrate 1 may be controlled, and the ceramic substrate 1 and the base plate 9 may be directly bonded together using a silicone adhesive or the like instead of the heat-resistant member 8.

[0031] The base plate 9 functions as a cooling member for cooling the ceramic substrate 1 that has been heated by plasma processing of the sample. The base plate may be, for example, a heat exchanger. In such a case, the base plate 9 may have a flow path for flowing a liquid or gas heat exchange medium.

[0032] The base plate 9 has a seventh surface 91 in contact with the sixth surface 82 of the heat-resistant member 8, an eighth surface 92 located on the opposite side of the seventh surface, and a third through hole 93 penetrating the seventh surface 91 and the eighth surface 92. The base plate 9 surrounds the cylindrical portion 4 at the third through hole 93. Specifically, when the heat-resistant member 8 and the base plate 9 are stacked, the second through hole 83 and the third through hole 93 are continuous, and one cylindrical portion 4 is located inside the continuous second through hole 83 and third through hole 93.

[0033] The heat-resistant member 8 and the base plate 9 may be joined together by an adhesive (not shown).

[0034] By joining the heat-resistant member 8 and the base plate 9 with an adhesive, it is possible to reduce misalignment between the heat-resistant member 8 and the base plate 9 .

[0035] The adhesive used to join the heat-resistant member 8 and the base plate 9 may have a lower thermal conductivity than the heat-resistant member 8. For example, the adhesive may be a silicone resin-based adhesive. In such a configuration, the adhesive functions as a heat insulating layer and can reduce the temperature difference between the fifth surface 81 and the sixth surface 82 of the heat-resistant member 8, thereby reducing warping of the heat-resistant member 8 caused by the temperature difference in the thickness direction of the heat-resistant member 8.

[0036] The sample holder 100 may have a fixing mechanism (not shown) that mechanically fixes the heat-resistant member 8 and the base plate 9 to the ceramic substrate 1. In this case, the heat-resistant member 8 contacts the ceramic substrate 1 without being bonded with an adhesive or the like.

[0037] When the heat-resistant member 8 and the ceramic substrate 1 are bonded together with an adhesive or the like, warping of the heat-resistant member 8 and the ceramic substrate 1 may occur due to the difference in the thermal expansion coefficient between the heat-resistant member 8 and the ceramic substrate 1. When warping occurs, the heat transferability between the heat-resistant member 8 and the base plate 9 becomes non-uniform. This causes non-uniformity in the in-plane heat transferability between the first surface 11 of the ceramic substrate 1, i.e., the sample support surface, and the base plate 9, which may reduce the temperature uniformity of the sample holder 100 in the in-plane direction. Therefore, when the heat-resistant member 8 and the base plate 9 are mechanically fixed to the ceramic substrate 1, the temperature uniformity of the sample holder 100 can be improved.

[0038] The fixing mechanism (not shown) may, for example, generate a pressing force that presses the heat-resistant member 8 and the base plate 9 against the first surface 11 of the ceramic substrate 1, thereby fixing the heat-resistant member 8 and the base plate 9 to the ceramic substrate 1 by the pressing force.

[0039] 2 , the cylindrical portion 4 may be bonded to the first surface 11 of the ceramic substrate 1 by a glass bonding material 6. The glass bonding material 6 is a bonding material containing a glass component as a main component. The glass bonding material 6 is located between the third surface 41 of the cylindrical portion 4 and the first surface 11 of the ceramic substrate 1.

[0040] The glass bonding material 6 has a relatively low thermal conductivity, so once it heats up, it is difficult for its temperature to drop. Therefore, when the glass bonding material 6 is positioned between the cylindrical portion 4 and the ceramic substrate 1, the heat retention function of the first flange portion 34 is likely to be maintained. In this way, the sample holder 100 having the glass bonding material 6 between the cylindrical portion 4 and the ceramic substrate 1 is more effective in retaining the heat of the first flange portion 34, and therefore can further reduce the deterioration of temperature uniformity.

[0041] Furthermore, compared to a case where the cylindrical portion 4 and the ceramic substrate 1 are not joined with the glass joining material 6, the gap between the third surface 41 of the cylindrical portion 4 and the first surface 11 of the ceramic substrate 1 can be sealed more effectively. Therefore, vacuum tightness can be ensured in an environment where vacuum tightness is required inside the cylindrical portion 4.

[0042] As shown in FIG. 2 , the sample holder 100 may include a conductive bonding material 5 that electrically connects the internal electrode 2 (e.g., the first electrode 21) and the second shank 32 of the metal terminal 3. The conductive bonding material 5 is located between the circumferential surface of the hole 13 of the ceramic substrate 1 and the second shank 32 of the metal terminal 3. This electrically connects the first electrode 21 exposed on the circumferential surface of the hole 13 to the second shank 32 of the metal terminal 3. The conductive bonding material 5 may also be located between the first surface 11 of the ceramic substrate 1 and the first flange 34 of the metal terminal 3. The conductive bonding material 5 may be a metal material such as silver, copper, titanium, or tin. Furthermore, by providing the conductive bonding material 5 on the circumferential surface of the hole 13, the internal electrode 2 and the metal terminal 3 can be electrically connected even when the length of the second shank 32 is shortened or in an embodiment that does not include the second shank 32. This allows the space in the hole 13 to be larger, reducing heat dissipation from the ceramic substrate 1 to the metal terminal 3, thereby improving the temperature uniformity of the sample holder 100.

[0043] Furthermore, by joining the metal terminal 3 and the ceramic substrate 1 with the conductive bonding material 5, the tensile strength at the joint can be improved compared to when there is no conductive bonding material between the metal terminal 3 and the ceramic substrate 1.

[0044] Second Embodiment FIG. 3 is a schematic enlarged view showing the configuration of part H1 of a sample holder 100 according to a second embodiment.

[0045] The outer diameter (radius of the outer peripheral surface) of the tubular portion 4 does not necessarily need to be constant from the third surface 41 to the fourth surface 42. For example, as shown in FIG. 3 , the outer diameter of the tubular portion 4 may increase from the first portion 431 to the third surface 41.

[0046] The second through hole 83 of the heat-resistant member 8 according to the second embodiment may have a third portion 831 and a fourth portion 832. The third portion 831 is a portion that surrounds the portion of the cylindrical portion 4 that constitutes the first portion 431 of the first through hole 43. The fourth portion 832 is a portion that covers the portion of the cylindrical portion 4 that constitutes the second portion 432 of the first through hole 43. The fourth portion 832 expands in diameter from the third portion 831 toward the fifth surface 81 of the heat-resistant member 8.

[0047] With this configuration, the fourth portion 832 can receive radiant heat from the second portion 432, compared to when the heat-resistant member 8 does not have the fourth portion 832, for example, when the heat-resistant member has a cylindrical through-hole formed with a diameter larger than the maximum diameter of the cylindrical portion 4. Therefore, the fourth portion 832 is heated by the received radiant heat, and the second portion 432 located in the internal space of the fourth portion 832 can be kept warm.

[0048] Furthermore, the second through-hole 83 has a narrow space between the fourth portion 832 and the third portion 831. This makes it difficult for the heated air in the internal space of the fourth portion 832 to escape from the internal space of the fourth portion 832, making it easier to maintain the second portion 432 in a warm state. Thus, according to the sample holder 100 of this embodiment, heat is unlikely to dissipate from the second portion 432 to the outside of the sample holder 100, so it is possible to reduce the deterioration of the temperature uniformity of the sample holder 100.

[0049] Third Embodiment FIG. 4 is a schematic enlarged view showing the configuration of part H1 of a sample holder 100 according to a third embodiment.

[0050] 4 , the tubular portion 4 may have a second flange portion 44. The second flange portion 44 is located at the end of the tubular portion 4 on the third surface 41 side, and protrudes outward from the outer circumferential surface of the tubular portion 4.

[0051] The heat capacity of the ceramic substrate 1 is greater than that of the cylindrical portion 4. Therefore, the amount of heat required to change the temperature of the ceramic substrate 1 is greater than the amount of heat required to change the temperature of the cylindrical portion 4. In other words, the ceramic substrate 1 is less susceptible to temperature changes and has a more stable temperature than the cylindrical portion 4. The cylindrical portion 4 having the second flange portion 44 has a larger contact area with the ceramic substrate 1, which has a larger heat capacity, compared to the cylindrical portion 4 without the second flange portion 44. This makes it easier to stabilize the temperature of the second portion 432, and therefore makes it easier to maintain the heat retention effect of the first flange portion 34. Therefore, a sample holder 100 having such a cylindrical portion 4 can further reduce deterioration in temperature uniformity.

[0052] Figure 4 shows an example in which the second flange portion 44 is provided on the tubular portion 4 according to the second embodiment, but the second flange portion 44 may also be provided on the tubular portion 4 according to the first embodiment (see Figure 2).

[0053] Fourth Embodiment FIG. 5 is a schematic enlarged view showing the configuration of part H1 of a sample holder 100 according to a fourth embodiment.

[0054] As shown in Fig. 5, the second portion 432 of the tubular portion 4 may have a corner 432a. In this case, the corner 432a may have a rounded surface. The corner 432a shown in Fig. 5 is a corner located between a surface of the inner surface of the second portion 432 that faces the outer peripheral surface of the first flange portion 34 and a surface that faces the second flange surface.

[0055] Since thermal stress tends to concentrate at corners, cracks due to thermal stress are likely to occur. By making at least one of the corners 432a of the second part 432 concavely curved, thermal stress is less likely to concentrate at the corner 432a, making it less likely for cracks to occur at the corner 432a. Therefore, with the sample holder 100 having such a configuration, the physical durability of the second part 432 is high.

[0056] The cylindrical portion 4 may have multiple corners in addition to the corner 432a. In such a case, the multiple corners of the cylindrical portion 4 may have a rounded surface shape. For example, as shown in Fig. 5, all corners located between the first portion 431 and the third surface 41 of the cylindrical portion 4 may have a rounded surface shape.

[0057] The rounded surface referred to here refers to a portion having a convex or concave curved shape when the cylindrical portion 4 is viewed in cross section from the radial direction, as shown in FIG.

[0058] 6 and 7 are schematic enlarged views showing an example of the configuration of the H1 portion in a sample holder 100 according to a fifth embodiment. In the fifth embodiment, another example of the shape of the cylindrical portion 4 will be described.

[0059] In the above-described embodiments, examples have been described in which the diameter of the first through hole 43 of the tubular portion 4 changes stepwise. However, the present invention is not limited to this. For example, as shown in Figures 6 and 7 , the diameter of the second portion 432 may change continuously from the first portion 431 to the third surface 41. In this case, in Figures 6 and 7 , the second portion 432 may have a dome-shaped internal space.

[0060] As shown in Fig. 6, the tubular portion 4 may have an outer peripheral surface that is convexly curved from the first portion 431 to the third surface 41. Alternatively, as shown in Fig. 7, the tubular portion 4 may have an outer peripheral surface that is concavely curved from the first portion 431 to the third surface 41.

[0061] Sixth Embodiment FIGS. 8 to 11 are enlarged schematic views showing the configuration of part H1 in a sample holder 100 according to a sixth embodiment.

[0062] As shown in FIG. 8 , a part of the glass bonding material 6 may be located inside the second portion 432 of the cylindrical portion 4 .

[0063] The glass bonding material 6 enters the second portion 432, narrowing the internal space of the second portion 432. As a result, the amount of air present inside the second portion 432 is reduced compared to when the glass bonding material 6 is present only between the ceramic substrate 1 and the cylindrical portion 4. This reduces the amount of heat dissipation due to air convection, making it easier to maintain the first flange portion 34 in a warm state. Therefore, the sample holder 100 having such a configuration can further reduce the deterioration of temperature uniformity.

[0064] 9, the glass bonding material 6 may cover at least a part of the first flange portion 34 of the metal terminal 3. In the example shown in FIG. 9, the glass bonding material 6 covers the outer peripheral surface of the first flange portion 34 and the second flange surface.

[0065] The thermal conductivity of the glass bonding material 6 is lower than that of air. Therefore, the glass bonding material 6 has a higher heat retention function than air. Therefore, by covering at least a part of the first flange portion 34 with the glass bonding material 6, the effect of retaining the heat of the first flange portion 34 can be further improved. Therefore, with the sample holder 100 having such a configuration, the deterioration of temperature uniformity can be further reduced.

[0066] 10 , the sample holder 100 may have a brazing filler metal 7 that covers at least a part of the first flange portion 34 of the metal terminal 3. The brazing filler metal 7 may be located, for example, straddling the first flange portion 34 and the conductive bonding material 5. The brazing filler metal 7 contains, for example, a metal such as silver as a main component.

[0067] The glass bonding material 6 may cover at least a part of the brazing material 7. Fig. 10 shows an example in which the entire brazing material 7 is covered by the glass bonding material 6, but as shown in Fig. 11 , a part of the brazing material 7 may be exposed from the glass bonding material 6.

[0068] The thermal conductivity of the glass bonding material 6 is lower than that of the brazing filler metal 7. Therefore, the glass bonding material 6 has a higher heat retention function than the brazing filler metal 7. Therefore, by covering at least a part of the brazing filler metal 7 that covers the first flange portion 34 with the glass bonding material 6, the effect of retaining the heat of the first flange portion 34 can be further improved. Therefore, the sample holder 100 having such a configuration can further reduce the deterioration of temperature uniformity.

[0069] Seventh Embodiment FIG. 12 is a schematic enlarged view showing the configuration of a second shaft portion 32 of a metal terminal 3 according to a seventh embodiment.

[0070] 12 , the metal terminal 3 may have a hollow portion 33 inside the second shank 32 that is inserted into the hole 13 of the ceramic substrate 1. The hollow portion 33 may have a bottomed shape in which one end in the axial direction of the second shank 32 is open and the other end in the axial direction of the second shank 32 is closed.

[0071] The thermal conductivity of air is lower than that of the metal terminal 3. The second shank 32 having the hollow portion 33 transfers heat less to the first flange portion 34 than a second shank portion without the hollow portion 33, i.e., a solid second shank portion. In this way, the sample holder 100 having the hollow portion 33 in the second shank 32 of the metal terminal 3 transfers heat less to the first flange portion 34, thereby reducing heat dissipation from the first flange portion 34. Therefore, the sample holder 100 according to the embodiment can further reduce deterioration in temperature uniformity.

[0072] Furthermore, the thermal expansion coefficient of the metal terminal 3 is higher than that of the ceramic substrate 1. Therefore, when the metal terminal 3 shrinks at room temperature, tensile stress is applied to the ceramic substrate 1, and repeated heating and cooling may cause cracks in the ceramic substrate 1. According to the sample holder 100 of this embodiment, the second shank 32 has a hollow portion 33, which makes it possible to reduce the volume of the metal portion of the second shank 32 compared to a solid second shank. This reduces radial shrinkage of the second shank 32, making it less likely for cracks to occur in the ceramic substrate 1.

[0073] 12 , when the end face of the second shank 32 located at the end of the second shank 32 and facing the first surface 11 of the ceramic substrate 1 is defined as the “end face 321” and the bottom face of the hole 13 is defined as the “bottom face 131,” the sample holder 100 according to the embodiment may have a space between the end face 321 and the bottom face 131. In other words, the axial length of the second shank 32 of the metal terminal 3 may be shorter than the axial depth of the hole 13.

[0074] The thermal expansion coefficient of the metal terminal 3 is higher than that of the ceramic substrate 1. The metal terminal 3 has a large thermal expansion because the temperature during brazing is higher than room temperature. Therefore, when the conductive bonding material 5 is brazed to the metal terminal 3, the second shank 32 extends in the axial direction and pushes up against the bottom surface 131 of the hole 13, which could cause the first flange 34 to float above the first surface 11 of the ceramic substrate 1. According to the sample holder 100 of the embodiment, the space between the end surface 321 and the bottom surface 131 makes it difficult for the second shank 32 to push up against the bottom surface 131, and therefore makes it difficult for the first flange 34 to float above the first surface 11 of the ceramic substrate 1.

[0075] Eighth Embodiment FIG. 13 is a schematic enlarged view showing the configuration of part H1 of a sample holder 100 according to an eighth embodiment.

[0076] The cylindrical portion 4 does not necessarily need to be bonded to the ceramic substrate 1. For example, the cylindrical portion 4 may be mechanically fixed to the ceramic substrate 1 by a fixing mechanism (not shown). As an example, as shown in FIG. 13 , a surface of the second through hole 83 of the heat-resistant member 8 that is located between the fifth surface 81 of the heat-resistant member 8 and the sixth surface 82 of the heat-resistant member 8 (see FIG. 1 ) and parallel to the first surface 11 of the ceramic substrate 1 is defined as a first contact surface 85. Furthermore, a surface of the outer surface of the cylindrical portion 4 that is located between the third surface 41 of the cylindrical portion 4 and the fourth surface 42 of the cylindrical portion 4 (see FIG. 1 ), parallel to the first surface 11 of the ceramic substrate 1, and in contact with the first contact surface 85 is defined as a second contact surface 45. The cylindrical portion 4 may be fixed to the ceramic substrate 1 by being pressed against the first surface 11 of the ceramic substrate 1 together with the heat-resistant member 8 by a fixing mechanism (not shown).

[0077] Although Figure 13 shows an example in which the cylindrical portion 4 is indirectly pressed against the ceramic substrate 1 via the heat-resistant member 8, the sample holder 100 may have a fixing mechanism for pressing the cylindrical portion 4 against the ceramic substrate 1, separate from the fixing mechanism for pressing the heat-resistant member 8 against the ceramic substrate 1.

[0078] The present disclosure has been described in detail above, but the present disclosure is not limited to the above-described embodiments, and various modifications, improvements, etc. are possible within the scope that does not deviate from the gist of the present disclosure.

[0079] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0080] The present technology may also be configured as follows: (1) A sample holder comprising: a ceramic substrate having a first surface and a second surface opposite to the first surface; an internal electrode located inside the ceramic substrate; a metal terminal electrically connected to the internal electrode; and an insulating tubular portion surrounding the metal terminal, wherein the tubular portion has a third surface in contact with the first surface, a fourth surface opposite to the third surface, and a first through hole penetrating the third and fourth surfaces and surrounding the metal terminal in the first through hole, wherein the metal terminal has a first shank and a first flange portion located at an end of the first shank and protruding from the first shank, the first flange portion being in contact with the first surface, and the first through hole having a first portion surrounding the first shank and a second portion whose diameter expands from the first portion toward the third surface and covers the first flange portion. (2) The sample holder according to (1), wherein the tubular portion is mainly composed of ceramic. (3) The sample holder according to (1) or (2), wherein the cylindrical portion has a second flange portion located at the end of the cylindrical portion on the third surface side and projecting outward from the outer peripheral surface of the cylindrical portion. (4) The sample holder according to any one of (1) to (3), wherein the sample holder includes a bonding material mainly composed of glass, located between the third surface and the first surface, and bonding the cylindrical portion to the ceramic substrate. (5) The sample holder according to (4), wherein a portion of the bonding material is located inside the second portion. (6) The sample holder according to (4) or (5), wherein the bonding material covers at least a portion of the first flange portion. (7) The sample holder according to any one of (4) to (6), wherein the sample holder includes a brazing material mainly composed of metal and covering at least a portion of the first flange portion, and wherein the bonding material covers at least a portion of the brazing material.(8) The sample holder according to any one of (1) to (7), having a fifth surface in contact with the first surface, a sixth surface opposite the fifth surface, and a second through hole penetrating the fifth and sixth surfaces, the second through hole having a heat-resistant member surrounding the cylindrical portion in the second through hole, the second through hole having a third portion surrounding the first portion of the cylindrical portion, and a fourth portion whose diameter increases from the third portion toward the fifth surface and covers the second portion of the cylindrical portion. (9) The sample holder according to any one of (1) to (8), the ceramic substrate containing aluminum nitride as a main component, and the cylindrical portion containing aluminum nitride or mullite as a main component. (10) The sample holder according to any one of (1) to (9), the second portion having at least one corner between the first portion and the first surface, the corner having a rounded surface shape. (11) The sample holder according to any one of (1) to (10), wherein the metal terminal has a second shaft portion located on the opposite side of the first flange portion from the first shaft portion and inside the ceramic substrate, and the second shaft portion has a hollow portion.

[0081] REFERENCE SIGNS LIST 1 ceramic substrate 2 internal electrode 3 metal terminal 4 cylindrical portion 5 conductive bonding material 6 bonding material (glass bonding material) 7 brazing material 8 heat-resistant member 9 base plate 11 first surface 12 second surface 13 hole portion 21 first electrode 22 second electrode 31 first axial portion 32 second axial portion 33 hollow portion 34 first flange portion 41 third surface 42 fourth surface 43 first through hole 44 second flange portion 81 fifth surface 82 sixth surface 83 second through hole 91 seventh surface 92 eighth surface 93 third through hole 100 sample holder 431 first portion 432 second portion 432a corner portion 831 third portion 832 fourth portion

Claims

1. A sample holder comprising: a ceramic substrate having a first surface and a second surface opposite the first surface; an internal electrode located inside the ceramic substrate; a metal terminal electrically connected to the internal electrode; and an insulating tubular portion surrounding the metal terminal, wherein the tubular portion has a third surface in contact with the first surface, a fourth surface opposite the third surface, and a first through hole penetrating the third and fourth surfaces, and surrounds the metal terminal in the first through hole, wherein the metal terminal has a first shank and a first flange portion located at an end of the first shank and extending from the first shank, the first flange portion being in contact with the first surface, and the first through hole has: a first portion surrounding the first shank; and a second portion which expands in diameter from the first portion towards the third surface and covers the first flange portion.

2. The sample holder according to claim 1, wherein the cylindrical portion is made primarily of ceramic.

3. A sample holder as described in claim 1 or 2, wherein the cylindrical portion has a second flange portion located at the end of the cylindrical portion on the third surface side and extending outward from the outer peripheral surface of the cylindrical portion.

4. A sample holder according to any one of claims 1 to 3, comprising a bonding material that is primarily composed of glass and is positioned between the third surface and the first surface to bond the cylindrical portion to the ceramic substrate.

5. A sample holder according to claim 4, wherein a portion of the bonding material is located inside the second portion.

6. A sample holder according to claim 4 or 5, wherein the bonding material covers at least a part of the first flange portion.

7. A sample holder according to any one of claims 4 to 6, which has a metal as its main component, is positioned between the ceramic substrate and the first flange portion, and has a brazing material that covers at least a portion of the first flange portion, and the joining material covers at least a portion of the brazing material.

8. A sample holder as claimed in any one of claims 1 to 7, having a fifth surface in contact with the first surface, a sixth surface located opposite the fifth surface, and a second through-hole penetrating the fifth and sixth surfaces, wherein the second through-hole has a heat-resistant member surrounding the cylindrical portion, and the second through-hole has a third portion surrounding the first portion of the cylindrical portion, and a fourth portion which expands in diameter from the third portion towards the fifth surface and covers the second portion of the cylindrical portion.

9. A sample holder according to any one of claims 1 to 8, wherein the ceramic substrate is made primarily of aluminum nitride, and the cylindrical portion is made primarily of aluminum nitride or mullite.

10. A sample holder according to any one of claims 1 to 9, wherein the second portion has at least one corner between the first portion and the first surface, and the corner has a rounded surface shape.

11. A sample holder according to any one of claims 1 to 10, wherein the metal terminal has a second shank located inside the ceramic substrate and opposite the first shank across the first flange, and the second shank has a hollow portion.

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