Airtight structure and electron microscope

Abstract

To provide an airtight structure capable of transmitting an electric signal while securing airtightness between a space to be evacuated and an atmosphere side space, and to provide an electron microscope equipped with the airtight structure.SOLUTION: The airtight structure includes a metal member having an opening and a first surface surrounding one opening end of the opening when viewed from a predetermined direction, a ceramic member facing the first surface in the predetermined direction and having a second surface surrounding the opening end when viewed from the predetermined direction, the ceramic member being attached to the metal member so as to close the opening end, a wire passing through the ceramic member in an airtight manner, and an O-ring disposed between the first surface and the second surface in contact with the first and second surfaces and surrounding the opening end when viewed from the predetermined direction in a crushed state. The arithmetic average roughness of the second surface is less than 0.3 μm.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an airtight structure and an electron microscope. [Background technology]

[0002] As an electron beam detection device applied to an electron microscope, Patent Document 1 describes a lens-coupling type camera in which light emitted from a scintillator layer in response to incidence of an electron beam is guided to an image sensor via a mirror and multiple lenses. The camera described in Patent Document 1 is configured to be retractable relative to the housing of the transmission electron microscope. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2010 / 0032576 Summary of the Invention [Problem to be solved by the invention]

[0004] The space inside the housing of the electron microscope is a vacuum space, so in the above-mentioned configuration, it is important to ensure airtightness between the vacuum space and the atmospheric space while transmitting electrical signals.

[0005] Therefore, an object of the present disclosure is to provide an airtight structure capable of transmitting electrical signals while ensuring airtightness between a vacuumed space and an atmospheric space, and an electron microscope equipped with such an airtight structure. [Means for solving the problem]

[0006] An airtight structure according to one aspect of the present disclosure is [1] "an airtight structure comprising: a metal member having an opening and a first surface surrounding one opening end of the opening when viewed from a predetermined direction; a ceramic member having a second surface facing the first surface in the predetermined direction and surrounding the opening end when viewed from the predetermined direction, the ceramic member being attached to the metal member so as to close the opening end; wiring airtightly penetrating the ceramic member; and an O-ring in contact with the first surface and the second surface and in a crushed state, positioned between the first surface and the second surface, surrounding the opening end when viewed from the predetermined direction, wherein the arithmetic mean roughness of the second surface is less than 0.3 μm."

[0007] In the airtight structure, the first surface of the metal member and the second surface of the ceramic member face each other in a predetermined direction, and the second surface of the ceramic member has an arithmetic mean roughness of less than 0.3 μm. An O-ring is disposed between the first surface of the metal member and the second surface of the ceramic member in a crushed state while contacting the first surface of the metal member and the second surface of the ceramic member. This ensures airtightness between the evacuated space and the atmosphere-side space when the space within the opening of the metal member is connected to the space to be evacuated and the space on the opposite side of the ceramic member from the opening is the atmosphere-side space. Furthermore, in the airtight structure, wiring airtightly penetrates the ceramic member. This ensures airtightness between the evacuated space and the atmosphere-side space when the space within the opening of the metal member is connected to the space to be evacuated and the space on the opposite side of the ceramic member from the opening is the atmosphere-side space. Therefore, the airtight structure allows electrical signals to be transmitted while ensuring airtightness between the evacuated space and the atmosphere-side space.

[0008] An airtight structure according to one aspect of the present disclosure may be [2] "the airtight structure according to the above [1], wherein the metal member has a groove that extends to surround the open end when viewed from the predetermined direction and that opens to the second surface side, and the first surface is a bottom surface of the groove." With this airtight structure, the position of the O-ring relative to the first surface and the second surface is stable, so that airtightness can be more reliably ensured between the space to be evacuated and the space on the atmospheric side.

[0009] An airtight structure according to one aspect of the present disclosure may be [3] "the airtight structure according to the above [1] or [2], wherein the second surface is an end face along a plane perpendicular to the predetermined direction." According to this airtight structure, when manufacturing a ceramic member, the second surface of the ceramic member can be easily polished, and therefore, the second surface of the ceramic member can be reliably obtained to have an arithmetic mean roughness of less than 0.3 μm.

[0010] An airtight structure according to one aspect of the present disclosure may be [4] "the airtight structure according to any one of the above [1] to [3], wherein the material of the ceramic member is aluminum oxide, zirconia, silicon carbide, yttria, single crystal YAG, or aluminum nitride." According to this airtight structure, by polishing the second surface of the ceramic member, it is possible to reliably obtain the second surface of the ceramic member having an arithmetic mean roughness of less than 0.3 μm.

[0011] The airtight structure according to one aspect of the present disclosure may be [5] "the airtight structure according to any one of the above [1] to [4], further comprising an image sensor attached to the ceramic member so as to face the opening and electrically connected to the wiring." With this airtight structure, it is possible to acquire an image in a vacuumed space, and to transmit an electrical signal of the acquired image to an external device arranged in an atmospheric space.

[0012] The airtight structure according to one aspect of the present disclosure may be [6] "the airtight structure according to any one of [1] to [5] above, in which no grease is disposed in the region between the first surface and the second surface." According to this airtight structure, even without using grease, it is possible to ensure sufficient airtightness between the space to be evacuated and the space on the atmospheric side, and to prevent outgassing from the grease into the space to be evacuated.

[0013] The airtight structure according to one aspect of the present disclosure may be [7] "the airtight structure according to any one of the above [1] to [6], wherein the ceramic member is configured to be detachable from the metal member." According to the airtight structure, it is possible to improve the maintainability of the components attached to the airtight structure.

[0014] An electron microscope according to one aspect of the present disclosure may be [8] "an electron microscope comprising an electron beam detection device including the airtight structure according to any one of [1] to [7] above, an electron beam source, and a sample support member arranged between the electron beam source and the electron beam detection device." As described above, in the airtight structure, the electron microscope allows electrical signals to be transmitted while ensuring airtightness between the evacuated space and the atmospheric space. [Effects of the Invention]

[0015] According to the present disclosure, it is possible to provide an airtight structure capable of transmitting electrical signals while ensuring airtightness between a vacuumed space and an atmospheric space, and an electron microscope equipped with such an airtight structure. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram showing the configuration of an example of an electron microscope. [Figure 2] FIG. 2 is a cross-sectional view of an airtight structure included in the electron beam detection device shown in FIG. [Figure 3] FIG. 3 is a diagram showing the evaluation results of the leak rate. [Figure 4] FIG. 4 is a cross-sectional view of the airtight structure of the first modification. [Figure 5] FIG. 5 is a cross-sectional view of the airtight structure of the second modification. DETAILED DESCRIPTION OF THE INVENTION

[0017] An example of the present disclosure will now be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0018] As shown in FIG. 1, an electron microscope 10 includes a housing 11, an electron beam source 12, a plurality of lens coils 13, a sample support 14, a plurality of lens coils 15, and an electron beam detection device 16. The electron microscope 10 is a transmission electron microscope. The electron beam source 12, the plurality of lens coils 13, the sample support 14, the plurality of lens coils 15, and the electron beam detection device 16 are arranged in this order along a direction A from one side in the direction A. The direction A is, for example, a vertical direction, and the one side in the direction A is, for example, an upper side. In the following description, the one side in the direction A (the upper side in FIG. 1) will be simply referred to as "the one side," and the other side in the direction A (the lower side in FIG. 1) will be simply referred to as "the other side."

[0019] The housing 11 houses an electron beam source 12, multiple lens coils 13, a sample support 14, multiple lens coils 15, and an electron beam detection device 16. The electron beam source 12 outputs an electron beam EB. The electron beam source 12 is, for example, an electron gun that emits the electron beam EB. The sample support 14 is disposed between the electron beam source 12 and the electron beam detection device 16. The sample support 14 supports a sample S. The sample support 14 is, for example, a sample holder that holds the sample S. The electron beam detection device 16 detects the electron beam EB that has transmitted through the sample S. The multiple lens coils 13 focus the electron beam EB output from the electron beam source 12 on a predetermined region of the sample S. The multiple lens coils 15 focus the electron beam EB that has transmitted through the sample S on a predetermined region of a scintillator layer 17 of the electron beam detection device 16. The space within the housing 11 is evacuated when an electron beam transmission image of the sample S is acquired.

[0020] The electron beam detection device 16 includes a scintillator layer 17, a fiber optic plate 18, and an image sensor 19. The scintillator layer 17, the fiber optic plate 18, and the image sensor 19 are arranged in this order from one side along direction A. The scintillator layer 17 emits light in response to the incidence of the electron beam EB. The fiber optic plate 18 guides the light emitted from the scintillator layer 17 to the image sensor 19. The image sensor 19 detects the light guided by the fiber optic plate 18. The electron beam detection device 16 includes an airtight structure 1. The airtight structure 1 is a structure for airtightly mounting the electron beam detection device 16 to the housing 11.

[0021] As shown in Fig. 2, the airtight structure 1 includes a metal member 2, a ceramic member 3, a support member 4, a wiring board 5, a Peltier element 6, wiring 7, an O-ring 8, a shim 9, and an image sensor 19. Note that although the scintillator layer 17 and the fiber optic plate 18 are not shown in Fig. 2, the fiber optic plate 18 is disposed on the image sensor 19, and the scintillator layer 17 is disposed on the fiber optic plate 18 (see Fig. 1).

[0022] The image sensor 19 is disposed on one surface of the wiring board 5. A plurality of terminals of the image sensor 19 are electrically connected to a plurality of wires of the wiring board 5. The image sensor 19 and the wiring board 5 are housed in a ceramic member 3 formed into a package shape. The ceramic member 3 is disposed on a support member 4. The support member 4 is formed, for example, from a metal. The ceramic member 3 includes a bottom wall 31 and a side wall 32. The side wall 32 is located on one side of the bottom wall 31 and defines an opening facing the bottom wall 31 in direction A. The bottom wall 31 is formed, for example, in the shape of a rectangular plate. The side wall 32 is formed, for example, in the shape of a rectangular frame. The wiring board 5 is fixed to the bottom wall 31 of the ceramic member 3 while being surrounded by the side wall 32 of the ceramic member 3.

[0023] The ceramic member 3 is provided with a plurality of lead pins 71. Each lead pin 71 extends from the bottom wall 31 to the other side. The plurality of lead pins 71 are terminal portions of a plurality of wires 7 provided on the ceramic member 3. Each wire 7 airtightly penetrates the ceramic member 3. The image sensor 19 is electrically connected to external wires via the plurality of wires of the wiring board 5 and the plurality of wires 7 (including the plurality of lead pins 71 that are terminal portions) provided on the ceramic member 3. This enables input and output of signals to and from the image sensor 19.

[0024] The image sensor 19 has a light receiving area including a plurality of pixels arranged two-dimensionally along a plane perpendicular to the direction A. The image sensor 19 is formed, for example, in the shape of a rectangular plate. The shape of the light receiving area when viewed from the direction A is, for example, rectangular. The image sensor 19 is, for example, a back-illuminated CMOS image sensor. The image sensor 19 may be, for example, a front-illuminated CMOS image sensor. The image sensor 19 may be another image sensor (for example, a back-illuminated CCD image sensor, a front-illuminated CCD image sensor, etc.). The image sensor 19 may be an area sensor or a line sensor.

[0025] A Peltier element 6 is disposed between the bottom wall 31 and the wiring board 5. The Peltier element 6 is fixed to the bottom wall 31. A heat absorbing portion of the Peltier element 6 is connected to the wiring board 5. A heat generating portion of the Peltier element 6 is connected to the bottom wall 31. When the electron microscope 10 is in operation, heat generated in the image sensor 19 is released to the support member 4 via the wiring board 5 and the Peltier element 6, and the temperature of the image sensor 19 is maintained within a constant range.

[0026] The metal member 2 includes a cylindrical main body 21, an inward flange 22, and an outward flange 23. The main body 21 is formed, for example, in the shape of a cylinder having a center line parallel to direction A. The inward flange 22 extends along the inner side surface of the main body 21. The outward flange 23 extends along the outer side surface of the main body 21. The metal member 2 is formed integrally from, for example, stainless steel, copper tungsten, or the like.

[0027] The metal member 2 has an opening 20. The opening 20 is defined by a main body portion 21 and an inward flange portion 22, and is open on both sides in direction A. An opening end (one opening end) 20a on the other side of the opening 20 is defined by the inward flange portion 22. The support member 4 is attached to the outward flange portion 23 by, for example, bolts, with a shim 9 disposed between the support member 4 and the outward flange portion 23.

[0028] The metal member 2 has a first surface 2a. When viewed from direction A, which is the direction in which the opening end 20a is open (predetermined direction), the first surface 2a surrounds the opening end 20a. In the airtight structure 1, a recess 24 that is open to the other side is formed in the metal member 2, and the opening end 20a is located on the bottom surface of the recess 24. The first surface 2a is a region of the bottom surface of the recess 24 that surrounds the opening end 20a. The direction in which the opening end 20a is open is also a direction that intersects with the plane that includes the opening end 20a.

[0029] The ceramic member 3 has a second surface 3a. The second surface 3a faces the first surface 2a in direction A and surrounds the open end 20a when viewed from direction A. The second surface 3a is an end face along a plane perpendicular to direction A. In other words, the ceramic member 3 does not have a portion that protrudes beyond the second surface 3a in direction A. In the airtight structure 1, the end face on one side of the side wall 32 corresponds to the second surface 3a.

[0030] The ceramic member 3 is made of aluminum oxide, zirconia, silicon carbide, yttria, single crystal YAG, or aluminum nitride. The ceramic member 3 is integrally formed from these materials. The arithmetic mean roughness of the second surface 3a is less than 0.3 μm. Such second surface 3a is formed by polishing. Examples of the polishing method include wet polishing and mirror polishing. The arithmetic mean roughness is obtained by extracting a portion of a roughness curve measured with a roughness meter over a reference length and expressing the unevenness of that section as an average value.

[0031] The O-ring 8 is disposed between the first surface 2a of the metal member 2 and the second surface 3a of the ceramic member 3, in contact with and compressed against the first surface 2a of the metal member 2 and the second surface 3a of the ceramic member 3. The O-ring 8 surrounds the open end 20a when viewed from direction A. No grease is disposed between the first surface 2a and the second surface 3a. In other words, the area between the first surface 2a and the second surface 3a is composed only of the O-ring 8 and a space.

[0032] As an example, the material of the O-ring 8 is fluororubber. As an example, when placed in a groove, the O-ring 8 is designed so that the tensile modulus is about 101%, the compressibility is 8 to 30% (e.g., 28%), and the filling rate is 90% or less (e.g., 75%).

[0033] When assembling the airtight structure 1, first, a unit composed of the ceramic member 3, the support member 4, the wiring board 5, the Peltier element 6, the wiring 7, and the image sensor 19 is prepared. Then, with the O-ring 8 disposed between the first surface 2a and the second surface 3a and with a shim 9 disposed between the outward flange portion 23 and the support member 4, the support member 4 is attached to the metal member 2, for example, by bolts. At this time, the distance between the first surface 2a and the second surface 3a is reduced, and the O-ring 8 is crushed between the first surface 2a and the second surface 3a. In this way, the airtight structure 1 is assembled, with airtightness ensured between the first surface 2a and the second surface 3a.

[0034] In the electron microscope 10, a metal member 2 is airtightly attached to a metal wall portion that is part of the housing 11 so as to close the opening of the metal wall portion, and this makes the space within the opening 20 of the metal member 2 a space that communicates with the space within the housing 11. This ensures that the space within the housing 11 is airtight, and makes it possible to evacuate the space within the housing 11. Note that ensuring airtightness between the metal wall portion and the metal member 2 can be achieved relatively easily by using a sealant, for example.

[0035] In the airtight structure 1 assembled as described above, the ceramic member 3 is attached to the metal member 2 so as to close the opening end 20a, and the image sensor 19 attached to the ceramic member 3 and electrically connected to the wiring 7 faces the opening 20. In the airtight structure 1, for example, the bolts are loosened and the support member 4 is removed from the metal member 2, thereby removing the ceramic member 3 from the metal member 2. In this way, in the airtight structure 1, the ceramic member 3 is configured to be detachable from the metal member 2.

[0036] As described above, in the airtight structure 1, the first surface 2a of the metal member 2 and the second surface 3a of the ceramic member 3 face each other in the direction A, and the arithmetic mean roughness of the second surface 3a of the ceramic member 3 is less than 0.3 μm. The O-ring 8 is disposed between the first surface 2a of the metal member 2 and the second surface 3a of the ceramic member 3 in a crushed state while contacting the first surface 2a of the metal member 2 and the second surface 3a of the ceramic member 3. This allows the space within the opening 20 of the metal member 2 to be in communication with the space to be evacuated (in the example described above, the space within the housing 11). When the space on the opposite side of the opening 20 with respect to the ceramic member 3 is the atmospheric space, airtightness can be ensured between the space to be evacuated and the atmospheric space. In addition, in the airtight structure 1, the wiring 7 passes through the ceramic member 3 in an airtight manner. As a result, when the space within the opening 20 of the metal member 2 is made to be a space that communicates with the space to be evacuated and the space on the opposite side of the opening 20 with respect to the ceramic member 3 is made to be an atmospheric space, an electrical signal can be transmitted between the space to be evacuated and the atmospheric space. Therefore, according to the airtight structure 1, an electrical signal can be transmitted between the space to be evacuated and the atmospheric space while ensuring airtightness.

[0037] In the airtight structure 1, the second surface 3a of the ceramic member 3 is an end face along a plane perpendicular to the direction A. This makes it easier to polish the second surface 3a of the ceramic member 3 when manufacturing the ceramic member 3, and therefore it is possible to reliably obtain the second surface 3a of the ceramic member 3 having an arithmetic mean roughness of less than 0.3 μm.

[0038] In the airtight structure 1, the material of the ceramic member 3 is aluminum oxide, zirconia, silicon carbide, yttria, single crystal YAG, or aluminum nitride. This ensures that the second surface 3a of the ceramic member 3 has an arithmetic mean roughness of less than 0.3 μm by polishing the second surface 3a.

[0039] In the airtight structure 1, the image sensor 19 is attached to the ceramic member 3 so as to face the opening 20, and is electrically connected to the wiring 7. This makes it possible to acquire an image in the evacuated space, and to transmit an electrical signal of the acquired image to an external device placed in the atmospheric space.

[0040] In the airtight structure 1, no grease is placed in the region between the first surface 2a of the metal member 2 and the second surface 3a of the ceramic member 3. This makes it possible to ensure sufficient airtightness between the space to be evacuated and the space on the atmospheric side without using grease, and also to prevent outgassing from the grease into the space to be evacuated.

[0041] In the airtight structure 1, the ceramic member 3 is configured to be detachable from the metal member 2. This allows for improved maintainability of the parts attached to the airtight structure 1.

[0042] The electron microscope 10 includes an electron beam detection device 16 including the airtight structure 1, an electron beam source 12, and a sample support part 14 arranged between the electron beam source 12 and the electron beam detection device 16. As a result, as described above, in the airtight structure, electrical signals can be transmitted while ensuring airtightness between the evacuated space and the atmospheric space.

[0043] FIG. 3 shows the evaluation results of the leak rate. FIG. 3(a) shows the evaluation results of the leak rate when only an O-ring is disposed in the region between the first surface 2a of the metal member 2 and the second surface 3a of the ceramic member 3, and FIG. 3(b) shows the evaluation results of the leak rate when an O-ring and grease are disposed in the region between the first surface 2a of the metal member 2 and the second surface 3a of the ceramic member 3. As shown in FIG. 3(a), when grease was not used, regardless of whether the ceramic member 3 was in the shape of a plate or a package (PKG), when the arithmetic mean roughness (Ra) of the second surface 3a of the ceramic member 3 was less than 0.3 μm, the leak rate was “OK” (i.e., airtightness could be ensured between the space to be evacuated and the space on the atmospheric side). When the arithmetic mean roughness (Ra) of the second surface 3a of the ceramic member 3 exceeded 0.3 μm, the leak rate was “NG” (i.e., airtightness could not be ensured between the space to be evacuated and the space on the atmospheric side). Furthermore, as shown in Figure 3(b), when grease was used, the leak rate was "OK" whether the arithmetic mean roughness (Ra) of the second surface 3a of the ceramic member 3 was less than 0.3 μm or more than 0.3 μm.

[0044] The present disclosure is not limited to the above-described example. First, an airtight structure 1A of a first modified example will be described with reference to Fig. 4. As shown in Fig. 4, the airtight structure 1A differs from the above-described airtight structure 1 mainly in that the metal member 2 is formed in a cylindrical shape and that the first surface 2a is the bottom surface of the groove 27. Note that in Fig. 4, the wiring board 5, the Peltier element 6, the image sensor 19, etc. are not shown.

[0045] One end face of the metal member 2 is airtightly attached to the other end face of a cylindrical side wall 111 that is part of the housing 11 via an O-ring 112. Note that using the O-ring 112 makes it relatively easy to ensure airtightness between the metal member 2 and the side wall 111 made of metal.

[0046] In the airtight structure 1A, the first surface 2a is the bottom surface of a groove 27 formed in the other end face of the side wall 26. The groove 27 extends to surround the open end 20a when viewed from direction A and opens to the second surface 3a. The second surface 3a is the end face on one side of the side wall 32 of the ceramic member 3, and the arithmetic mean roughness of the second surface 3a is less than 0.3 μm.

[0047] The O-ring 8 is disposed between the first surface 2a of the metal member 2 and the second surface 3a of the ceramic member 3 in a crushed state and in contact with the first surface 2a of the metal member 2 and the second surface 3a of the ceramic member 3. The O-ring 8 is disposed along the groove 27 and surrounds the open end 20a when viewed from direction B. By disposing the O-ring 8 along the groove 27, the position of the O-ring 8 relative to the first surface 2a and the second surface 3a is stabilized, making it possible to more reliably ensure airtightness between the space to be evacuated and the space on the atmospheric side.

[0048] Next, an airtight structure 1B of a second modified example will be described with reference to Fig. 5. As shown in Fig. 5, the airtight structure 1B is configured as a port for drawing out wiring from a space to be evacuated to an atmospheric space. The airtight structure 1B includes a cylindrical metal member 2, a plate-shaped ceramic member 3, wiring 7, and an O-ring 8.

[0049] The metal member 2 includes a bottom wall 25 and a side wall 26. The side wall 26 is located on one side of the bottom wall 25 and defines an opening facing the bottom wall 25 in direction A. One end face of the side wall 26 is airtightly attached to the other end face of a cylindrical side wall 111 that is part of the housing 11 via an O-ring 112. Note that the use of the O-ring 112 makes it relatively easy to ensure airtightness between the metal member 2 and the side wall 111, which is made of metal.

[0050] The metal member 2 has an opening 20 and a first surface 2a. The opening 20 is formed in a side wall 26 and is open to the inside and outside of the side wall 26. The first surface 2a is formed in the side wall 26 and faces the outside of the side wall 26. The first surface 2a surrounds an outer opening end 20a of the opening 20 when viewed from direction B. Direction B is the direction in which the opening end 20a is open (a predetermined direction).

[0051] The ceramic member 3 is attached to the outer side surface of the side wall 26, for example, with bolts, so as to close the open end 20a. In other words, the ceramic member 3 is attached to the metal member 2 so as to close the open end 20a. The ceramic member 3 has a second surface 3a. The second surface 3a faces the first surface 2a in direction B and surrounds the open end 20a when viewed from direction B. The second surface 3a is one main surface of the plate-shaped ceramic member 3. In other words, the second surface 3a is one end surface in the thickness direction of the plate-shaped ceramic member 3. The arithmetic mean roughness of the second surface 3a is less than 0.3 μm.

[0052] In the airtight structure 1B, the first surface 2a is the bottom surface of a groove 27 formed on the outer side surface of the side wall 26. The groove 27 extends so as to surround the open end 20a when viewed from direction B, and opens to the second surface 3a.

[0053] The O-ring 8 is disposed between the first surface 2a of the metal member 2 and the second surface 3a of the ceramic member 3 in a crushed state and in contact with the first surface 2a of the metal member 2 and the second surface 3a of the ceramic member 3. The O-ring 8 is disposed along the groove 27 and surrounds the open end 20a when viewed from direction B. By disposing the O-ring 8 along the groove 27, the position of the O-ring 8 relative to the first surface 2a and the second surface 3a is stabilized, making it possible to more reliably ensure airtightness between the space to be evacuated and the space on the atmospheric side.

[0054] The wiring 7 passes through the ceramic member 3 in an airtight manner. The wiring 7 includes a connector 72 arranged on the main surface of the ceramic member 3 opposite the opening 20, and a connector 73 arranged on the main surface of the ceramic member 3 on the opening 20 side. An end of the wiring electrically connected to a wiring board 5A arranged in the space to be evacuated is connected to the connector 73. An end of the wiring electrically connected to a wiring board 5B arranged in the space on the atmospheric side is connected to the connector 72. Electrical signals can be transmitted between the space to be evacuated and the space on the atmospheric side.

[0055] In the above-described airtight structures 1 and 1A, the second surface 3a of the ceramic member 3 does not have to be an end surface along a plane perpendicular to the direction A, and the ceramic member 3 may have a portion protruding from the second surface 3a in the direction A. In the above-described airtight structure 1B, the second surface 3a of the ceramic member 3 does not have to be an end surface along a plane perpendicular to the direction B, and the ceramic member 3 may have a portion protruding from the second surface 3a in the direction B.

[0056] In the above-described airtight structures 1, 1A, and 1B, the material of the ceramic member 3 may be a ceramic other than “aluminum oxide, zirconia, silicon carbide, yttria, single-crystal YAG, or aluminum nitride.” In the above-described airtight structures 1, 1A, and 1B, grease may be disposed between the first surface 2a of the metal member 2 and the second surface 3a of the ceramic member 3.

[0057] The above-described airtight structures 1, 1A, and 1B can also be applied to devices other than the electron microscope 10, which is a transmission electron microscope. As an example, the above-described airtight structures 1, 1A, and 1B can also be applied to a scanning electron microscope. Furthermore, the above-described airtight structure 1B can also be applied to a vacuum chamber of a large-scale synchrotron radiation facility. [Explanation of symbols]

[0058] 1, 1A, 1B...airtight structure, 2...metal member, 2a...first surface, 3...ceramic member, 3a...second surface, 7...wiring, 8...O-ring, 10...electron microscope, 12...electron beam source, 14...sample support portion, 16...electron beam detection device, 19...image sensor, 20...opening, 20a...opening end (one opening end), 27...groove, A, B...direction (predetermined direction).

Claims

1. a metal member having an opening and a first surface surrounding one end of the opening when viewed from a predetermined direction; a ceramic member attached to the metal member so as to close the open end, the ceramic member having a second surface facing the first surface in the predetermined direction and surrounding the open end when viewed from the predetermined direction; Wiring that passes through the ceramic member in an airtight manner; an O-ring disposed between the first surface and the second surface in a crushed state and in contact with the first surface and the second surface, and surrounding the open end when viewed from the predetermined direction; An airtight structure, wherein the second surface has an arithmetic mean roughness of less than 0.3 μm.

2. An electron beam detection device including the airtight structure according to claim 1; an electron beam source; a sample support disposed between the electron beam source and the electron beam detection device.

Images