Stage

Abstract

[Problem] To provide a stage that can be transferred by vacuum or the like. [Solution] This stage is characterized by comprising a sample platform on which a sample is loaded, a shutter function whereby it is possible to separate the atmosphere inside and outside of the stage, and a seal section.　In addition, a preferred embodiment of the stage of the present invention is characterized by further comprising a first valve capable of automatic discharge. Furthermore, a preferred embodiment of the stage of the present invention is characterized by further comprising a second valve of which the opening / closing degree can be adjusted.

Description

stage

[0001] The present invention relates to a stage, and more particularly to a stage that can be transported under vacuum or the like.

[0002] In recent years, high-resolution analysis using electron microscopes such as transmission electron microscopes (TEM) and scanning transmission electron microscopes (STEM) has progressed, and there is a demand for high-resolution analysis, for example, from the nano-order to the pico-order. Recently, "in-situ observation," in which a sample is cooled (or heated, or electric or magnetic field applied, or rotated) while being observed inside the electron microscope, has attracted attention. In particular, sample cooling is considered effective in reducing damage to the sample caused by the electron beam, and sample cooling has been attempted from this perspective.

[0003] Although SEM has a lower magnification than TEM, there are fewer restrictions on the size of the specimen that can be observed, making it possible to observe larger samples. It is also easier to use than TEM, making observation and analysis less difficult than with TEM. Therefore, electron microscope manufacturers are developing products that can be used to observe a variety of objects.

[0004] For example, a known example of a device having a cooling means is a sample processing device using a scanning electron microscope, which is provided with a cooling stage in the sample chamber of the scanning electron microscope on which a sample from which water has sublimated is placed, and a manipulator that extends above the cooling stage and cuts out necessary components of the sample under observation by the scanning electron microscope (Patent Document 1).

[0005] Japanese Unexamined Patent Publication No. 62-85840

[0006] Despite this need for cooling, in conventional technologies, including the above-mentioned Patent Document 1, the only method of fixing a sample to an existing cooling stage is to attach the sample to the upper surface of the sample pedestal, and cooling is limited to being performed from the bottom of the sample.

[0007] Furthermore, conventional techniques allow for the observation of samples by transferring them from an external location to a liquid nitrogen-cooled SEM stage under vacuum. This involves inserting a cartridge containing the sample into the SEM using a rod or similar tool. However, because this involves transferring the sample from outside the electron microscope, it is physically impossible to bring electrical wiring into the vacuum chamber. For this reason, many research users are eager for an SEM stage that allows them to observe samples while simultaneously cooling them and applying electricity.

[0008] SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a stage that can be transported in a vacuum or the like.

[0009] In order to achieve the above object, the inventors have conducted extensive research into the stage mechanism and have come up with the present invention.

[0010] That is, the stage of the present invention is characterized by having a sample pedestal on which a sample is mounted, a shutter function capable of isolating the atmosphere inside the stage from the atmosphere outside, and a sealing portion.

[0011] In a preferred embodiment of the stage of the present invention, the stage further comprises a first valve capable of automatic exhaust.

[0012] In a preferred embodiment of the stage of the present invention, the stage further comprises a second valve whose opening and closing degree is adjustable.

[0013] In a preferred embodiment of the stage of the present invention, the stage further comprises a motor capable of opening and closing the shutter of the shutter function.

[0014] In a preferred embodiment of the stage of the present invention, the stage further comprises a feed-through portion.

[0015] In a preferred embodiment of the stage of the present invention, the stage further comprises an electrode portion.

[0016] In a preferred embodiment of the stage of the present invention, the sample stage is characterized in that it includes an attachment mounting device.

[0017] In a preferred embodiment of the stage of the present invention, the stage further comprises a cooling section.

[0018] In a preferred embodiment of the stage of the present invention, the stage further comprises a thermoelectric element disposed adjacent to the cooling portion.

[0019] In a preferred embodiment of the stage of the present invention, the attachment mounting device is a screw hole or a clamp.

[0020] In a preferred embodiment of the present invention, the thermoelectric element is a thermoelectric element utilizing at least one effect selected from the Peltier effect and the Thomson effect.

[0021] In a preferred embodiment of the stage of the present invention, the heat radiation side of the thermoelectric element and the cooling portion are in contact with each other.

[0022] In a preferred embodiment of the stage of the present invention, the cooling portion is made of at least one of a solid refrigerant, a liquid refrigerant, and a gas refrigerant.

[0023] In a preferred embodiment of the stage of the present invention, the sample pedestal and the thermoelectric element are in contact with each other.

[0024] The stage of the present invention has the advantageous effect of enabling transfer under vacuum, Ar, etc. Furthermore, according to another aspect of the stage of the present invention, electrodes, etc. can also be arranged, which has the advantageous effect of enabling, for example, observation of an object while applying electricity to a battery.

[0025] FIG. 1 shows a conceptual diagram of a sample pedestal portion of a stage in one embodiment of the present invention. FIG. 1(a) shows a top view of the sample pedestal portion of a stage in one embodiment of the present invention, FIG. 1(b) shows a side view of the sample pedestal portion of the stage, and FIG. 1(c) shows a perspective view of the sample pedestal portion of the stage. FIG. 2 shows an embodiment of a thermoelectric element applicable to the present invention. FIG. 2(a) shows a cross-sectional view of a Peltier element, and FIG. 2(b) shows a schematic diagram of the principle of the Peltier element. FIG. 3 shows a perspective view of a stage with a shutter function in one embodiment of the present invention. FIG. 4 shows a top view of a stage with a shutter function in one embodiment of the present invention. FIG. 5 shows a side cross-sectional view of a stage with a shutter function in one embodiment of the present invention. FIG. 6 shows a side view of a stage with a shutter function in one embodiment of the present invention. FIG. 7 shows a side cross-sectional view of a stage with a shutter function in one embodiment of the present invention. FIG. 8 shows a five-view diagram of a stage with a shutter function in one embodiment of the present invention. Figures 8(a) and (e) are side views of a stage with a shutter function according to one embodiment of the present invention. Figure 8(c) is a top view of a stage with a shutter function according to one embodiment of the present invention. Figure 8(b) is a front view of a stage with a shutter function according to one embodiment of the present invention. Figure 8(d) is a rear view of a stage with a shutter function according to one embodiment of the present invention. Figure 9 is a perspective view of a stage with a shutter function according to one embodiment of the present invention. Figure 10 is a diagram showing an example of a cooling SEM stage system according to one embodiment of the present invention.

[0026] The stage of the present invention is characterized by having a sample pedestal for mounting a sample, a shutter function capable of isolating the atmosphere inside the stage from the atmosphere outside, and a sealing portion. In the present invention, the sample pedestal for mounting a sample is not particularly limited, including its shape and structure, as long as it is capable of mounting a sample to be observed in an electron microscope. Furthermore, the present invention also has a shutter function capable of isolating the atmosphere inside the stage from the atmosphere outside. By incorporating this shutter function, it is possible to create a structure that allows for independent vacuum transfer, and also allows for electrodes to be placed, enabling observation while electricity is flowing through the battery. For example, in the present invention, a glove box can be evacuated to remove moisture and the like, and then filled with Ar. After mounting a sample in the glove box and sealing it with a vacuum transfer shutter with a cooling function under Ar gas or vacuum using the shutter function, the stage can be transferred to an SEM under vacuum or Ar.

[0027] Furthermore, in the present invention, the sealing part is not particularly limited as long as it can isolate the atmosphere inside the stage from the atmosphere outside during transfer under vacuum, etc. As long as it can isolate the atmosphere inside the stage (sample installation side) from the atmosphere outside, the sealing part may be provided on the stage side, the shutter side, or on one side or both sides.

[0028] Furthermore, a preferred embodiment of the stage of the present invention is characterized by further comprising a first valve capable of automatic evacuation. For example, in a glove box, Ar gas can be filled, the SEM can be brought into the glove box, and the SEM can be evacuated and the lid opened to achieve non-exposure to the atmosphere. However, if the shutter is suddenly opened, a large amount of argon may flow into the SEM, causing the SEM to malfunction. Therefore, the inflow can be mitigated by providing a first valve capable of automatic evacuation. For example, by providing a check valve as the first valve capable of automatic evacuation, the valve can release the differential pressure generated between the SEM and the stage chamber, making it possible to evacuate the chamber or the SEM more safely.

[0029] Furthermore, a preferred embodiment of the stage of the present invention is characterized in that it further comprises a second valve whose degree of opening and closing is adjustable. By providing a second valve whose degree of opening and closing is adjustable, it becomes possible to slowly replace the vacuum with an Ar atmosphere or the like. For example, when transferring from an SEM to a glove box, the stage chamber is in a vacuum, so the second valve whose degree of opening and closing is adjustable can be used as an opening and closing valve to slowly replace the vacuum with argon inside the glove box.

[0030] In a preferred embodiment of the stage of the present invention, the stage further comprises a motor capable of opening and closing the shutter of the shutter function. The motor allows the shutter to be opened and closed smoothly. The motor may directly operate the shutter, or, as will be described later, the motor may open and close the shutter via, for example, a gear. The shutter can also be remotely controlled by a motor drive.

[0031] Furthermore, a preferred embodiment of the stage of the present invention is characterized by further comprising a feedthrough unit. As described above, conventional non-exposure to atmosphere systems involves vacuum transport of samples on cartridges from outside the electron microscope, making it impossible to apply voltage. To allow electricity to flow, a feedthrough is required to separate the wiring from the vacuum. A feedthrough can refer to a vacuum component attached to a vacuum wall that separates the vacuum from the atmosphere in order to transport and control electrical signals, physical motion, fluids, etc., to the inside of a device maintained in a vacuum state. In the present invention, the feedthrough unit makes it possible to observe samples while applying voltage, for example.

[0032] In a preferred embodiment of the stage of the present invention, the stage further comprises an electrode unit. One or more electrode units can be provided. In the present invention, the electrode configuration desired by the user can be attached. This allows researchers to customize the way electricity is applied as desired.

[0033] In a preferred embodiment of the stage of the present invention, the sample pedestal is characterized by comprising an attachment mounting device. That is, in an embodiment of the present invention comprising the attachment mounting device, attachments can be easily attached and detached, and various attachments can be replaced. The attachment mounting device may be provided at the position of the above-mentioned electrode, or may be provided separately from the electrode.

[0034] In a preferred embodiment of the stage of the present invention, the stage further comprises a cooling unit. In the present invention, the cooling unit is not particularly limited in shape, structure, etc., as long as it is capable of cooling the sample observed in the electron microscope. While the sample pedestal portion can be cooled by a cooling unit or Peltier element, the portions other than the cooling unit are at higher temperatures. Therefore, if an attachment is connected and fixed to a portion other than the vicinity of the cooling unit (outside the cooling system), the attachment will receive heat from outside the cooling system and warm up. In this case, when the attachment warms up, heat is transferred to the sample, warming the sample that has been cooled, resulting in a reduction in the cooling effect. In an embodiment of the sample pedestal of the present invention that includes an attachment mounting device, the attachment is present within the cooling system via the attachment mounting device, thereby enabling the sample to be cooled with minimal heat loss.

[0035] In a preferred embodiment of the stage of the present invention, the attachment mounting device is a screw hole or a clamp, from the viewpoint of enabling attachments to be fixed firmly and with good reproducibility. In the present invention, the attachment mounting device, e.g., a screw portion, is provided, making it easy to change attachments depending on the purpose. Double-sided tape and adhesives are difficult to remove once the attachment is fixed, and are not intended for reuse. Furthermore, each time the attachment is replaced, the thermal contact between the attachment and the sample pedestal changes, and the attachment's posture is difficult to control. In contrast, in the present invention, the attachment mounting device allows attachments to be changed with good reproducibility, thereby offering the advantage of being able to flexibly accommodate a variety of applications.

[0036] Furthermore, the attachment is not particularly limited as long as it can be attached, but in a preferred embodiment of the stage of the present invention, the attachment is at least one selected from an FIB grid holder attachment, a sample fixing attachment, and an electrical current attachment. In addition to the FIB grid holder attachment and the top surface fixing attachment, when a sample is observed with the clamping orientation turned sideways, a temperature gradient can be created by cooling the clamped portion to the free end. In the present invention, an attachment capable of creating such a temperature gradient can also be installed. Attachments that have a cold trap function to prevent contamination by arranging a cooling member near the top surface of the sample are also conceivable.

[0037] Here, the term "cold trap" can be understood as a device that cools and captures trace amounts of suspended matter (gases, such as hydrocarbons) in a vacuum. In other words, if gas is present in the vacuum, it is expected that it will be bombarded by the sample along with the electron beam and accumulate on the sample. When a cooling element is placed near the top surface, as in the present invention, a mechanism can be realized that surrounds the vicinity of the sample with a cooled metal element (cooling element) within a range that does not block the electron beam irradiation, thereby creating a locally high vacuum region. This allows for the construction of a mechanism that cools and condenses the released gas for collection, thereby preventing the gas present in the vacuum inside the electron microscope from coming into contact with the sample.

[0038] Furthermore, when considering applications such as not only cooling but also passing a current through the sample, the influence of external temperatures can be reduced by fixing the electrodes and sample clamps using (via) an attachment device such as a screw, or by fixing and passing a current through the sample on an extended table fixed by the attachment device. Such attachments can also be installed in the present invention.

[0039] In a preferred embodiment of the stage of the present invention, the attachment mounting device is made of a thermally conductive material. Examples of materials with high thermal conductivity include copper and copper alloys, aluminum and aluminum alloys, silver, and gold. In the present invention, for example, a stage that cools a sample in a scanning electron microscope (SEM) has an attachment mounting device, such as a screw hole, integrally formed on the sample base, allowing attachments of various shapes and configurations to be attached. This incorporates the attachment into the cooling system, minimizing the influence of external heat and enabling various cooling modes.

[0040] In a preferred embodiment of the stage of the present invention, the cooling section is characterized by comprising at least one of a solid refrigerant, a liquid refrigerant, and a gas refrigerant. The refrigerant in the cooling section can be appropriately selected depending on the application and is not particularly limited. A preferred medium is a liquid from the viewpoint of versatility. While a liquid (such as water) can be used to adjust the temperature using a general-purpose device (a cooling chiller), it can become a source of vibration because it is a fluid. Liquid nitrogen or liquid helium can also be used as the liquid.

[0041] Furthermore, in the present invention, the cooling unit may be a solid refrigerant, from the viewpoint that the influence of vibrations due to water flow or pulsating flow can be reduced to almost zero compared to water cooling. That is, in the present invention, the heat dissipation surface of a Peltier element or the like can be cooled with a solid refrigerant such as dry ice. This makes it possible to reduce to almost zero the influence of vibrations due to water flow or pulsating flow compared to water cooling. Furthermore, in the case of a solid, it is difficult to adjust the temperature of the cooling unit, but this can be controlled using a thermoelectric element as described below.

[0042] On the other hand, even when a cooling gas is flowed at a very low flow rate, the influence of vibration is minimal, and this can also be used in the present invention. Examples of cooling gases include gasified liquid nitrogen. This allows for effective cooling of the sample. In the present invention, the cooling gas is not limited to liquid nitrogen. It is believed that simply passing a weak gas through a heat dissipation surface is practically unaffected by vibration. Therefore, as described above, even when a solid refrigerant is actually used as the cooling unit, it is sufficient to apply cold air through a gap rather than pressing it against the heat dissipation surface. Similarly, when liquid nitrogen gas is used, passing the cooling gas through the heat dissipation surface allows observation without being affected by vibration. The difficulty of adjusting the temperature of the cooling unit can be addressed by using a thermoelectric element, as described below.

[0043] In a preferred embodiment of the stage of the present invention, the stage further comprises a thermoelectric element installed adjacent to the cooling unit. In the present invention, the location of the thermoelectric element is not particularly limited as long as it is installed adjacent to the cooling unit. The thermoelectric element enables efficient temperature control, i.e., temperature control, to be achieved at the required temperature for the sample. In an embodiment using a thermoelectric element, the cooling and heating response is excellent, minimizing the effects of thermal drift. Furthermore, the improved cooling and heating response allows for precise temperature control. In an embodiment using a thermoelectric element, cooling and heating can be achieved with a single element simply by reversing the current flow direction. At the same time, the rapid cooling and heating response makes it easy to change the temperature to a desired level. Furthermore, precise temperature control is possible by adjusting the input power output, enabling precise temperature control and minimizing the effects of thermal drift.

[0044] In a preferred embodiment of the stage of the present invention, the heat dissipation side of the thermoelectric element is in contact with the cooling unit. That is, in the present invention, the thermoelectric element may be positioned adjacent to the cooling unit. For example, a cooling unit such as a solid refrigerant may be pressed against the heat dissipation side (heat dissipation surface side), or a gap may be provided between the cooling unit and the solid refrigerant to allow cold air to be applied. When applying cold air, natural convection or forced convection using a fan or the like may be used. However, if forced convection generates vibrations, natural convection is preferable, depending on the degree of forced convection. Even in the case of natural convection, the solid refrigerant has a sufficiently low temperature, so a large temperature gradient exists between the heat dissipation surface side and the cold air from the cooling unit such as a solid refrigerant. Therefore, sufficient heat transfer occurs, ensuring adequate cooling of the heat dissipation surface. Note that forced convection is more effective than natural convection, and water cooling is more effective than air cooling for heat dissipation.

[0045] In a preferred embodiment of the present invention, the thermoelectric element is a thermoelectric element utilizing at least one of the Peltier effect and the Thomson effect. The Peltier effect (also called the Peltier effect) is the effect of converting electrical energy into thermal energy. When two dissimilar metals (or semiconductors) are connected and a current is passed through them, a temperature difference occurs between the two ends. This is particularly called a Peltier element and is used to cool precision instruments, wine cellars, and the like. The Thomson effect is the effect of generating heat other than Joule heat (heat is absorbed when the current is reversed) when a current is passed through a uniform metal (or dissimilar metals) with a temperature gradient. Both can generate and absorb heat.

[0046] A heat dissipation member may be provided between the thermoelectric element and the cooling unit or the like from the viewpoint of efficient heat dissipation from the thermoelectric element.

[0047] In a preferred embodiment of this stage of the present invention, the thermoelectric element is a Peltier element, which provides good cooling and heating response and minimizes the effects of thermal drift. Peltier elements are also called Peltier elements (thermo-modules), a general term for elements that utilize the Peltier effect. The currently mainstream structure that is considered to have the best performance is called the "π-type," which has a structure as shown in Figure 2. By passing a current through a PN junction using a P-type semiconductor and an N-type semiconductor, heat can be dissipated between the PN and absorbed between the NP.

[0048] The principle is as follows. Figure 2 shows one embodiment of a thermoelectric element applicable to the present invention. Figure 2(a) shows a cross-sectional view of a Peltier element, and Figure 2(b) shows a schematic diagram of the Peltier element principle. In Figure 2(a), 21 denotes the hot-side metal (mainly Cu), 22 denotes a ceramic substrate (mainly alumina), 23 denotes a heat dissipation surface, 24 denotes an N-type semiconductor, 25 denotes a P-type semiconductor, 26 denotes an electric wire, 27 denotes a power source, 28 denotes heat absorption, 29 denotes the conduction band of the N-type semiconductor, 30 denotes heat dissipation, 31 denotes the positive side, 32 denotes the heat absorption side, 33 denotes the valence band, 34 denotes the heat dissipation side, 35 denotes the negative side, 36 denotes the cold-side metal (mainly Cu), 37 denotes the cold-side metal (mainly Cu), 38 denotes electrons, 39 denotes holes, and 40 denotes the conduction band of the P-type semiconductor.

[0049] In FIG. 2A, the negative pole is connected to metal 36 on the N-type semiconductor 24 side. Therefore, the voltage pushes electrons up from the conduction band of metal 36 to the conduction band 29 of N-type semiconductor 24. At this time, because there is an energy gap between the conduction band of metal 36 and the conduction band 29 of N-type semiconductor 24, the electrons absorb thermal energy from metal 36, thereby cooling it. The electrons then flow and fall from the conduction band 29 of N-type semiconductor 24 to the conduction band of metal 21. The energy gap between the two bands causes the electrons to release thermal energy. In this way, the hot-side metal 21 is heated. The flowing electrons then fall from the conduction band of metal 21 to holes 39 flowing through the P-type semiconductor 25, releasing thermal energy and heating the hot-side metal 21. In the P-type semiconductor 25, the voltage generates holes 39, which flow from the cold side 37 to the hot side 21. The electrons generated at that time are pushed up into the conduction band of the cold side metal by the voltage, absorbing thermal energy according to the energy gap and cooling the cold side metal 37. In this way, heat is transported from the cold side to the hot side of the Peltier module as a result of the current flow. In addition to the thermal energy carried by the current, there is also thermal energy carried by thermal conduction, but because the thermal energy carried by thermal conduction flows in the opposite direction, the less this is, the better the performance of the Peltier module. In other words, removing the thermal energy from the hot side as quickly as possible using a heat sink or similar will enable the Peltier module to perform well. Simply put, electrons carry (remove) heat.

[0050] There are no particular restrictions on the semiconductor material, and any can be used, but Bi-Te semiconductors are considered to have the best performance and are the mainstream.

[0051] Peltier element performance can generally be measured by the temperature difference ΔT that can be achieved relative to the temperature Th when the heat-dissipating side is kept constant. For example, for Th = 75, 50, or 25°C, ΔT = 93, 85, or 75°C. If the heat-dissipating side were simply cooled to, say, liquid nitrogen temperature (-196°C), the heat-absorbing side would likely reach temperatures exceeding minus 200°C. However, due to the characteristics of the material, ΔT is actually estimated to be 10°C at temperatures near liquid nitrogen. The lower the temperature, the less heat there is to excite electrons, reducing the Peltier element's cooling capacity. Furthermore, the lower the temperature, the greater the electrical resistance of the semiconductor, causing it to self-heat due to electrical current, reducing the overall cooling capacity.

[0052] In a preferred embodiment of the present invention, the heat radiation side of the thermoelectric element is in contact with the cooling unit, from the viewpoint that a lower temperature can be set by cooling the heat radiation side of the thermoelectric element. Although the following examples mainly describe the case of cooling, heating by the thermoelectric element is also possible in the present invention. During heating, the lower surface of the thermoelectric element cools, so the cooling unit must be heated before use (processed at a temperature higher than the lower surface). In this case, it can function as a heating unit rather than a cooling unit.

[0053] In the case of heating, the phenomenon is simply reversed compared to cooling, but the practicality of the Peltier element, or other thermoelectric device, also depends on its configuration (whether it is multi-stage or not). Basically, when aiming for the lowest possible temperatures, multi-stage thermoelectric devices, such as Peltier elements, can be used. In this case, a pyramid-like structure can be used, with the heat-absorbing surface (top layer) being smaller and the heat-dissipating surface increasing in size. This structure is designed because the larger the surface area, the greater the heat absorption capacity, and the heat absorbed by the smaller upper layer is dissipated by the larger lower layer. When using a Peltier element for heating by reversing the polarity of the current, it is not simple; heat from the larger lower layer tends to flow into the smaller upper layer all at once. If the upper layer cannot absorb the heat, heat accumulates in the middle layer, which tends to be higher than the upper layer. Therefore, most Peltier elements, even when used for heating, are expected to reach around +100°C (a temperature at which the solder at the joint does not deteriorate). Peltier elements create heat absorption and heat dissipation surfaces through the movement of electrons, and by controlling the amount of current passing through the Peltier element, it is possible, in principle, to precisely control the temperature from near room temperature to the negative range. These effects enable stable, high-resolution observations.

[0054] In a preferred embodiment of the stage of the present invention, the sample pedestal and the thermoelectric element are in contact with each other, from the viewpoint of cooling the area following the sample pedestal.

[0055] The following describes a stage according to an embodiment of the present invention with reference to the drawings, but the present invention is not limited to these examples. It goes without saying that appropriate modifications can be made without departing from the spirit of the present invention.

[0056] Figure 1 shows a conceptual diagram of the sample pedestal portion of a stage in one embodiment of the present invention. Figure 1(a) shows a top view of the sample pedestal portion of the stage in one embodiment of the present invention, Figure 1(b) shows a side view of the sample pedestal portion of the stage, and Figure 1(c) shows a perspective view of the sample pedestal portion of the stage. In Figure 1, 1 indicates the sample pedestal, 2 indicates an attachment mounting device or electrode, 3 indicates a thermoelectric element (if a thermoelectric element is required), 4 indicates a heat dissipation member, and 5 indicates a cooling unit.

[0057] The role of each component and the connections between components of the stage sample pedestal in one embodiment of the present invention will be described below with reference to the drawings. First, there is the stage body. In FIG. 1 , the stage body includes a cooling unit 5. However, in the case of the heating described above, the underside of the thermoelectric element cools during heating, so the cooling unit must be heated (processed at a higher temperature than the underside). In this case, the cooling unit can function as a heating unit rather than a cooling unit. While this example also includes a thermoelectric element 3, in an embodiment without the thermoelectric element 3, the thermoelectric element 3 can be omitted. Since this example uses the thermoelectric element 3, a heat dissipation member 4 may be provided as needed, as shown in the drawing. In this example, the attachment mounting device 2 is specifically a screw hole. However, as described above, a clamp or the like may also be used. There is no particular limitation as long as the attachment can be attached and detached. The attachment mounting device 2 is preferably made of a thermally conductive material. This further reduces heat loss. If an attachment mounting device is not used, the attachment mounting device can be an electrode 2.

[0058] As long as the Peltier element and the sample pedestal are in thermal contact, they may be directly above each other or may be offset laterally and extended. Although the clamp is shown standing vertically in the figure, it may also clamp the sample horizontally. One feature is that the attachment holes or electrodes are integrated with the sample pedestal. The attachment holes or electrodes may be machined as a single unit, or the screw holes may be manufactured separately and then press-fit or glued in later.

[0059] Although not shown, a FIB grid can also be installed as an attachment. In this case, the FIB grid holder attachment can be attached to the FIB grid holder pedestal using copper screws or the like. The FIB sample holder pedestal can also be fixed to the sample pedestal as a cooling attachment. The FIB mesh can be clamped vertically in the center of the FIB grid's slot. In this way, the cooling effect can reduce damage caused by electron beams and ion beams. If the pedestal portion is made a little larger, it can also be used to clamp and observe normal samples. A structure that allows the sample to be clamped horizontally is also possible.

[0060] Furthermore, although not shown, it is also possible to fix the sample from above using an attachment. The upper surface of the observation sample can be fixed using a sample fixing attachment that is installed on top. If the sample is fixed from above using an attachment and the attachment is made of a thermally conductive material, it is possible to cool the sample from above as well. In the present invention, attachments can be replaced with good reproducibility by installing an attachment mounting device, which has the advantage of being able to flexibly accommodate a variety of applications.

[0061] Next, Figure 3 is a perspective view of a stage with a shutter function according to one embodiment of the present invention. In Figure 3, 50 denotes a shutter, 51 denotes a motor, 52 denotes a sample pedestal (below which is a cooling unit, if any), 53 denotes an attachment mounting device or electrode, 54 denotes a first valve, and 55 denotes a second valve. In Figure 3, the shutter 50 is shown in an open state, illustrating an example of the interior of the stage. The shutter can be opened and closed. Although not shown, when the shutter is closed, the interior of the stage can be evacuated or regulated by Ar, enabling vacuum transfer. As described below, the motor 51 can open and close the shutter 50. 52 can also function as a cooling or heating unit for the sample pedestal and, ultimately, the sample. In this example, cooling is performed using a Peltier element. Peltier cooling enables overwhelming throughput. Liquid nitrogen cooling requires significant time before and after observation: it takes one hour to cool the sample, another hour for the temperature to stabilize, and another hour to return the sample to room temperature after observation. However, Peltier cooling simply uses an electric current, allowing for extremely responsive cooling—down to -100°C in three minutes and back to room temperature in one minute—which dramatically increases the speed of research. Previously, liquid nitrogen was used because typical Peltier cooling stages could only cool to -50°C. A temperature of -50°C was insufficient to mitigate damage from electron beams and focused ion beams, and cooling to -80°C to -100°C was required. Therefore, even if Peltier cooling was desired, the only option was to use liquid nitrogen. Surprisingly, this invention makes it possible to achieve -100°C using the Peltier cooling method.

[0062] Reference numeral 53 denotes an attachment attachment device or electrodes. In the case of an attachment attachment device, the contents of FIG. 1 described above can be cited as an example. The attachment attachment device and electrodes can be used together, but electrodes alone may also be used. Electrodes can be attached in any shape desired by the user, and their shape, arrangement, etc. are not limited. While four electrodes are shown in FIG. 3, there can be one or more electrodes. The way electricity is applied can be customized as desired by researchers.

[0063] Furthermore, 54 is a first valve, which can be automatically evacuated when evacuated. The glove box is filled with Ar gas or the like, brought to the SEM, and the SEM is evacuated and the lid is opened to prevent exposure to the atmosphere. However, if the shutter is suddenly opened, a large amount of argon may flow into the SEM, causing it to malfunction. Therefore, by installing an automatically evacuated valve, such as a check valve, a pressure difference is created between the SEM and the stage chamber. This pressure difference causes the valve to open, creating a vacuum inside the chamber.

[0064] A second valve 55 may be, for example, a valve whose degree of opening and closing can be adjusted. Conversely to the above, when the stage is transferred from the SEM to the glove box, the second valve 55 functions as an opening and closing valve that slowly replaces the vacuum in the glove box with argon because the stage chamber is in a vacuum.

[0065] Next, FIG. 4 is a top view of a stage with a shutter function according to one embodiment of the present invention. In FIG. 4, 50 denotes a shutter, 51 denotes a motor, 52 denotes a sample pedestal (with a cooling unit (if provided) below), 54 denotes a first valve, 55 denotes a second valve, 60 denotes a shutter opening / closing screw, and 61 denotes a lid connecting gear. The above descriptions can be referenced for the shutter 50, motor 51, sample pedestal (with a cooling unit (if provided) below), 52, first valve 54, and second valve 55. 60 denotes a shutter opening / closing screw. When the motor 51 rotates, the shutter opening / closing screw 60 rotates, thereby moving the shutter forward to seal the interior of the stage. In this example, the lid connecting gear 61 is used to utilize the rotation of the motor to open and close the shutter.

[0066] Next, Figure 5 is a side cross-sectional view of a stage with a shutter function according to one embodiment of the present invention. In Figure 5, 70 denotes a rotating shaft, 71 denotes a seal auxiliary part, 72 denotes a shutter, and 73 denotes a shutter opening / closing screw. In this example, the rotating shaft 70 is threaded, and a corresponding mating thread is threaded into the shutter opening / closing screw 73. When the rotating shaft 70 is rotated by a motor, the rotation is transmitted to the shutter opening / closing screw 73, and the shutter operates to the right in Figure 5 in response to the rotation. A seal, such as an O-ring, is located on the back side of the shutter 72, and when the shutter closes, the atmosphere inside the stage is isolated from the outside. In this example, the seal auxiliary part 71 is a tapered part installed on the side of the shutter. When the shutter closes, a guide pin bites into the tapered part 71, pressing the lid (stage lid, shutter) against the base (stage body). This further enhances the sealing effect of the O-ring. Although the seal is provided on the shutter side, it may be provided on the stage side.

[0067] Next, Figure 6 is a side view of a stage with a shutter function according to one embodiment of the present invention. In Figure 6, 80 denotes a guide rail, 81 denotes a guide pin, and 82 denotes a tapered portion. Guide pin 81 can move along the guide rail in response to the opening and closing movement of the shutter. The tapered portion 82 is tapered, and is designed so that in the final stage of shutter closure, guide pin 81 applies a downward force to the lid (the upper part of the stage, the shutter), thereby holding the lid down and allowing the O-ring to work effectively against the sealing surface. The guide pins 81 on both sides and the tapered portion 82 firmly press the entire lid against the sealing surface. This structure provides a compact atmosphere isolation function.

[0068] Next, Figure 7 is a diagram showing a side cross-sectional view of a stage with a shutter function in one embodiment of the present invention. In Figure 7, 90 indicates a first valve and 91 indicates a feed-through portion. The above description of the first valve 90 can be referred to. In the present invention, the position of the feed-through portion is not particularly limited. The feed-through portion makes it possible, for example, to observe a sample while applying a voltage.

[0069] Next, Fig. 8 is a diagram showing five-sided views of a stage with a shutter function in one embodiment of the present invention. Figs. 8(a) and (e) are diagrams showing side views of a stage with a shutter function in one embodiment of the present invention. Fig. 8(c) is a diagram showing a top view of a stage with a shutter function in one embodiment of the present invention. Fig. 8(b) is a diagram showing a front view of a stage with a shutter function in one embodiment of the present invention. Fig. 8(d) is a diagram showing a rear view of a stage with a shutter function in one embodiment of the present invention.

[0070] Next, Fig. 9 is a perspective view of a stage with a shutter function in one embodiment of the present invention. In Fig. 9, 50 denotes a shutter, 51 denotes a motor, 52 denotes a sample base (below which is a cooling unit, if any), and 53 denotes an attachment mounting device or electrode. For these, please refer to the explanation in Fig. 3.

[0071] Next, Figure 10 is a diagram showing an example of a cooling SEM stage system according to one embodiment of the present invention. In Figure 10, 100 denotes a temperature controller, 101 denotes a feedthrough, and 102 denotes a coolant supply device. The temperature controller 100 controls the temperature inside the stage. The feedthrough 101 is a component for passing electricity, temperature measurement, and cooling water through a vacuum. The coolant supply device 102 is a device that can supply coolant without vibration.

[0072] In this way, the stage of the present invention can provide a shutter function, and if the stage is designed to be capable of vacuum transfer independently, it can also be designed to accommodate electrodes, which has the advantageous effect of enabling observation while electricity is flowing through the battery. In particular, it has been found that in an embodiment using Peltier cooling, speedy experiments can be performed.

[0073] The stage can be transported under vacuum or the like, and in-situ observation can be performed even under cooling conditions, making the device applicable to a wide range of technical fields.

[0074] 1 Sample pedestal 2 Attachment mounting device or electrode 3 Thermoelectric element (if thermoelectric element is required) 4 Heat dissipation member 5 Cooling unit 21 Hot side metal (mainly Cu) 22 Ceramic substrate (mainly alumina) 23 Heat dissipation surface 24 N-type semiconductor 25 P-type semiconductor 26 Electric wire 27 Power supply 28 Heat absorption 29 Conduction band of N-type semiconductor 30 Heat dissipation 31 Positive side 32 Heat absorption side 33 Valence band 34 Heat dissipation side 35 Negative side 36 Cold side metal (mainly Cu) 37 Cold side metal (mainly Cu) 38 Electron 39 Hole 40 Conduction band of P-type semiconductor 50 Shutter 51 Motor 52 Sample pedestal (below is cooling unit (if provided)) 53 Attachment mounting device or electrode 54 First valve 55 Second valve 60: Screw for opening and closing the shutter 61: Gear for connecting the opening and closing cover 70: Rotating shaft 71: Sealing auxiliary part 72: Shutter 73: Screw for opening and closing the shutter 80: Guide rail 81: Guide pin 82: Tapered part 90: First valve 91: Feed-through part 100: Temperature controller 101: Feed-through 102: Refrigerant supply device

Claims

1. A stage characterized by having a sample base on which a sample is mounted, a shutter function capable of isolating the atmosphere inside the stage from the atmosphere outside, and a sealing section.

2. The stage of claim 1 further comprising a first valve capable of self-venting.

3. The stage according to claim 1 or 2, further comprising a second valve whose opening and closing degree can be adjusted.

4. A stage according to any one of claims 1 to 3, further comprising a motor capable of opening and closing the shutter of the shutter function.

5. A stage according to any one of claims 1 to 4, further comprising a feed-through portion.

6. A stage according to any one of claims 1 to 5, further comprising an electrode portion.

7. A stage according to any one of claims 1 to 5, characterized in that the sample base is provided with an attachment mounting device.

8. A stage according to any one of claims 1 to 6, further comprising a cooling section.

9. The stage of claim 7, further comprising a thermoelectric element disposed adjacent said cooling portion.

10. A stage according to any one of claims 6 to 8, characterized in that the attachment mounting device is a screw hole or a clamp.

11. The stage according to claim 9 or 10, characterized in that the thermoelectric element is a thermoelectric element utilizing at least one of the Peltier effect and the Thomson effect.

12. The stage according to any one of claims 9 to 11, characterized in that the heat dissipation side of the thermoelectric element and the cooling section are in contact with each other.

13. The stage according to any one of claims 8 to 12, characterized in that the cooling section is made of at least one of a solid refrigerant, a liquid refrigerant, and a gaseous refrigerant.

14. The stage according to any one of claims 9 to 13, characterized in that the sample base and the thermoelectric element are in contact with each other.

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