JP2023026841A - Sample holder and charged particle beam device - Google Patents

Abstract

To provide a sample holder that does not require liquid nitrogen for cooling a cold trap.SOLUTION: A sample holder 100 for a charged particle beam device includes a Peltier element 30 having a heat dissipation surface 32 and a heat absorption surface 34, a first heat conducting member 40 connected to the heat dissipation surface 32, and a sample holding unit 10 connected to the first heat conducting member 40 and holding a sample S, a second heat conducting member 42 connected to the heat absorption surface 34, and a cold trap 20 connected to the second heat conducting member 42.SELECTED DRAWING: Figure 1

Description

The present invention relates to a sample holder and a charged particle beam device.

A charged particle beam apparatus such as a scanning electron microscope or a transmission electron microscope irradiates a sample with an electron beam to observe and analyze the sample.

It is known that contamination adheres to the sample surface due to electron beam irradiation during observation as a problem when observing and analyzing a sample by irradiating it with an electron beam. Contamination is largely caused by hydrocarbon gas. A high-vacuum apparatus such as an electron microscope uses vacuum grease, pump oil, etc., and thus contamination with hydrocarbon gas cannot be avoided.

For example, Patent Document 1 discloses an electron microscope with a cold trap. In the electron microscope disclosed in Patent Document 1, organic gas molecules and the like heading toward the sample are adsorbed by a cooling trap to prevent contamination of the sample. A cold trap is thermally connected to the liquid nitrogen tank.

JP-A-9-320504

However, in the electron microscope disclosed in Patent Document 1, liquid nitrogen is used to cool the cold trap, so the operator must handle the liquid nitrogen. Liquid nitrogen is extremely cold and poses a risk of frostbite and suffocation.

One aspect of the sample holder according to the present invention is
A sample holder for a charged particle beam device,
a Peltier element having a heat dissipation surface and a heat absorption surface;
a first heat conducting member connected to the heat dissipation surface;
a sample holder that is connected to the first thermally conductive member and holds a sample;
a second heat conducting member connected to the heat absorbing surface;
a cold trap connected to the second thermally conductive member;
including.

In such a sample holder, since the cooling trap is connected to the heat absorbing surface of the Peltier element through the second heat conducting member, the cooling trap can be cooled by the Peltier element. Therefore, such a sample holder does not require liquid nitrogen to cool the cold trap, reducing the risk of frostbite and suffocation for the operator. Furthermore, in such a sample holder, since the sample holder is connected to the heat radiation surface of the Peltier element via the first heat conducting member, the sample can be heated by the Peltier element.

One aspect of the charged particle beam device according to the present invention is
Includes sample holder as described above.

The perspective view which shows typically the sample holder which concerns on one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows typically the sample holder which concerns on one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows typically the sample holder which concerns on one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows typically the sample holder which concerns on one Embodiment of this invention. The figure which shows the structure of the transmission electron microscope containing the sample holder which concerns on one Embodiment of this invention.

Preferred embodiments of the present invention will be described in detail below with reference to the drawings. It should be noted that the embodiments described below do not unduly limit the scope of the invention described in the claims. Moreover, not all the configurations described below are essential constituent elements of the present invention.

1. Sample Holder First, a sample holder according to one embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view schematically showing a sample holder 100 according to one embodiment of the invention. 1, for the sake of convenience, part of the outer cylinder 70, part of the first support member 50, and part of the second support member 52 are omitted. FIG. 2 is a cross-sectional view schematically showing the sample holder 100. As shown in FIG. 3 and 4 are cross-sectional views schematically showing part of the sample holder 100. FIG.

A sample holder 100 is a sample holder for a transmission electron microscope. A sample holder 100 is a sample holder used in a side entry stage for inserting a sample from the side of a pole piece of an objective lens of a transmission electron microscope.

As shown in FIGS. 1 to 4, the sample holder 100 includes a sample holder 10, a cooling trap 20, a Peltier element 30, a first heat conducting member 40, a second heat conducting member 42, and a first support. It includes a member 50 , a second support member 52 , a connector 60 , an outer cylinder 70 and a base 72 .

The sample holder 10 holds the sample S. The sample holder 10 is provided at the tip of the sample holder 100 . The sample holding part 10 is supported by the first heat conducting member 40 . The sample holding part 10 is fixed to the tip of the first heat conducting member 40 .

In the illustrated example, the sample holder 10 is a plate-shaped sample table, and the sample S is fixed to the sample table. The sample S is fixed to the sample holder 10 by, for example, leaf springs or screws. The specimen holder 10 is provided with a through hole 12 for passing the electron beam EB. The sample S is arranged so as to overlap the through-hole 12 .

Cold trap 20 is supported by a second heat conducting member 42 . The cold trap 20 is fixed to the tip of the second heat conducting member 42 . The cold trap 20 may be detachable from the second heat conducting member 42 .

The cooling trap 20 is provided so as to surround the sample holder 10 . In the illustrated example, the cooling trap 20 is in the shape of a rectangular tube, and has a space inside which accommodates the sample holder 10 . Although not shown, the cold trap 20 may be cylindrical. The shape of the cooling trap 20 is not particularly limited, and it does not have to surround the sample holder 10 as long as it is arranged in the vicinity of the sample holder 10 .

The cold trap 20 is provided with a first through hole 22 through which the electron beam EB incident on the sample S passes, and a second through hole 24 through which the electron beam EB that has passed through the sample S passes. In the sample holder 100, the electron beam EB passes through the first through-hole 22, the through-hole 12, and the second through-hole 24.
pass in that order.

The Peltier element 30 is an element that utilizes the Peltier effect. The Peltier element 30 has a heat dissipation surface 32 and a heat absorption surface 34 . In the Peltier element 30 , when a current is passed in a predetermined direction, heat is absorbed on the heat absorbing surface 34 and radiated on the heat radiating surface 32 .

The first heat conducting member 40 is thermally connected to the heat dissipation surface 32 of the Peltier element 30 . In the illustrated example, the first heat conducting member 40 is in contact with the heat dissipation surface 32 of the Peltier element 30 . The first heat conducting member 40 thermally connects the heat dissipation surface 32 of the Peltier device 30 and the sample holder 10 . Thereby, the Peltier element 30 can heat the sample holder 10 . For example, the Peltier element 30 can heat the sample holder 10 to about 100.degree.

The second heat conducting member 42 is thermally connected to the heat absorbing surface 34 of the Peltier element 30 . In the illustrated example, the second heat conducting member 42 is in contact with the heat absorbing surface 34 of the Peltier element 30 . The second heat conducting member 42 thermally connects the heat absorbing surface 34 of the Peltier device 30 and the cooling trap 20 . Thereby, the cooling trap 20 can be cooled by the Peltier device 30 . For example, the Peltier element 30 can cool the cold trap 20 to about -100.degree.

The first thermally conductive member 40 and the second thermally conductive member 42 are made of a material with high thermal conductivity. The first thermally conductive member 40 and the second thermally conductive member 42 may be made of, for example, metal with high thermal conductivity. The first heat conducting member 40 and the second heat conducting member 42 may be heat pipes.

The first support member 50 and the second support member 52 support the first heat conduction member 40 and the second heat conduction member 42 . The first support member 50 is arranged at the front end of the outer cylinder 70 , and the second support member 52 is arranged at the rear end of the outer cylinder 70 . The first support member 50 and the second support member 52 are made of a material with low thermal conductivity. Therefore, heat is less likely to be conducted between the first thermally conductive member 40 and the second thermally conductive member 42 .

Connector 60 is electrically connected to an external power supply. Power is supplied to the Peltier element 30 from an external power source through the connector 60 . That is, the sample holder 100 does not have a power supply, and power is supplied to the Peltier element 30 from the outside.

The first heat conducting member 40 , the second heat conducting member 42 , the first support member 50 , and the second support member 52 are housed inside the outer cylinder 70 . The outer cylinder 70 is cylindrical, for example. Outer cylinder 70 is fixed to base 72 . A connector 60 is provided on the base 72 . Although not shown, the base portion 72 is provided with wiring for electrically connecting the Peltier element 30 and the connector 60 .

2. Transmission Electron Microscope Next, a transmission electron microscope including the sample holder 100 will be described with reference to the drawings. FIG. 5 is a diagram showing the configuration of a transmission electron microscope 200 including the sample holder 100. As shown in FIG.

In the transmission electron microscope 200, the sample S held by the sample holder 100 is irradiated with an electron beam (an example of a charged particle beam) EB, and the electrons transmitted through the sample S form an image, thereby obtaining a transmission electron microscope image of the sample S. (TEM image) can be obtained. Further, in the transmission electron microscope 200, a scanning electron microscope image (STEM image) can be obtained by scanning the sample S with a narrowly focused electron beam EB.

Transmission electron microscope 200 includes sample holder 100, as shown in FIG. The transmission electron microscope 200 further includes an electron gun 210, an irradiation lens 211, a deflector 212, a sample stage 214, an objective lens 216, an intermediate lens 217, a projection lens 218, a detector 220, and a Peltier element. a power supply 230;

The electron gun 210 emits an electron beam EB. The electron gun 210, for example, accelerates electrons emitted from the cathode at the anode and emits an electron beam EB.

The irradiation lens 211 converges the electron beam EB emitted from the electron gun 210 and irradiates the sample S with the electron beam EB.

The deflector 212 deflects the electron beam EB with which the sample S is irradiated. A STEM image can be acquired by deflecting the electron beam EB with which the sample S is irradiated by the deflector 212 .

The sample stage 214 holds the sample S via the sample holder 100 . The sample stage 214 has a moving mechanism that moves the sample S in the horizontal direction. By moving the sample S in the horizontal direction using the movement mechanism of the sample stage 214, the field of view can be moved.

The objective lens 216 is a first-stage lens that forms a TEM image with the electron beam EB that has passed through the sample S. The objective lens 216 , the intermediate lens 217 and the projection lens 218 constitute an imaging lens system, which forms a TEM image on the detector 220 with the electron beam EB that has passed through the sample S.

A detector 220 captures a TEM image formed by the imaging lens system. The detector 220 is, for example, a digital camera such as a CCD (Charge Coupled Device) camera.

A Peltier element power supply 230 supplies power to the Peltier element 30 of the sample holder 100 . In the transmission electron microscope 200 , the Peltier element power supply 230 that supplies power to the Peltier element 30 is not mounted on the sample holder 100 but is provided outside the sample holder 100 . Thereby, the weight of the sample holder 100 can be reduced.

Although the case where the sample holder 100 is applied to a transmission electron microscope has been described above, for example, the sample holder 100 can also be applied to charged particle beam devices such as scanning electron microscopes, focused ion beam devices, and electron beam microanalyzers. Applicable.

3. Operation In the sample holder 100, when power (voltage) is supplied from the Peltier element power supply 230 to the Peltier element 30, the cooling trap 20 connected to the heat absorption surface 34 via the second heat conduction member 42 is cooled, and the first heat conduction member 42 is cooled. The sample holder 10 connected to the heat dissipation surface 32 via the member 40 is heated. The voltage value applied to the Peltier element 30 is calibrated in advance so that the temperature of the sample holder 10 and the temperature of the cooling trap 20 can be controlled by the voltage value applied to the Peltier element 30 .

By cooling the cold trap 20 with the Peltier device 30, hydrocarbon-based gas molecules are adsorbed on the cold trap 20, and contamination adhering to the sample S can be reduced.

The sample S is heated by heating the sample holder 10 with the Peltier element 30 . By heating the sample S, for example, gas can be released from the sample S (degassing). Further, for example, by heating a biological sample or the like, the sample can be homogenized. Further, for example, by heating the sample S, changes in the state of the sample S due to temperature changes can be observed in situ.

After finishing the observation of the sample S, the power supply from the Peltier element power supply 230 to the Peltier element 30 is stopped.

4. Effect The sample holder 100 includes a Peltier element 30 having a heat dissipation surface 32 and a heat absorption surface 34, a first heat conduction member 40 connected to the heat dissipation surface 32, and a sample S connected to the first heat conduction member 40. a second heat conducting member 42 connected to the heat absorbing surface 34; and a cold trap 20 connected to the second heat conducting member 42.

As described above, in the sample holder 100 , the cooling trap 20 is connected to the heat absorbing surface 34 of the Peltier element 30 via the second heat conducting member 42 , so that the cooling trap 20 can be cooled by the Peltier element 30 . Therefore, the sample holder 100 does not require liquid nitrogen for cooling the cold trap 20, reducing the risk of frostbite and suffocation of the operator.

Here, when the liquid nitrogen tank and the cold trap are thermally connected to cool the cold trap, boiling of the liquid nitrogen in the tank may become a source of vibration. Since the sample holder 100 can cool the cold trap 20 without using liquid nitrogen, the vibration of the apparatus can be reduced.

Furthermore, in the sample holder 100 , the sample holder 10 is connected to the heat radiation surface 32 of the Peltier element 30 via the first heat conducting member 40 , so the sample S can be heated by the Peltier element 30 .

In sample holder 100 , cold trap 20 surrounds sample holder 10 . Therefore, in the sample holder 100, contamination of the sample S can be efficiently reduced.

In the sample holder 100, the cold trap 20 is provided with a first through hole 22 for passing the electron beam EB irradiated to the sample S and a second through hole 24 for passing the electron beam EB that has passed through the sample S. there is Therefore, the sample holder 100 can be used as a sample holder for transmission electron microscopes.

Transmission electron microscope 200 does not require liquid nitrogen for cold trap 20 because sample holder 100 is included.

The transmission electron microscope 200 includes a Peltier element power supply 230 that supplies power to the Peltier element 30 , and power is supplied to the Peltier element 30 from the Peltier element power supply 230 via the connector 60 . Therefore, in the transmission electron microscope 200, the weight of the sample holder 100 can be reduced as compared with the case where the sample holder 100 has a Peltier element power source.

The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments. "Substantially the same configuration" means, for example, a configuration having the same function, method, and result, or a configuration having the same purpose and effect. Moreover, the present invention includes configurations in which non-essential portions of the configurations described in the embodiments are replaced. In addition, the present invention includes a configuration that achieves the same effects or achieves the same purpose as the configurations described in the embodiments. In addition, the present invention includes configurations obtained by adding known techniques to the configurations described in the embodiments.

DESCRIPTION OF SYMBOLS 10... Sample holding part 12... Through-hole 20... Cooling trap 22... First through-hole 24... Second through-hole 30... Peltier element 32... Heat dissipation surface 34... Heat absorption surface 40... First heat Conductive member 42 Second heat conductive member 50 First support member 52 Second support member 60 Connector 70 Outer cylinder 72 Base 100 Sample holder 200 Transmission electron microscope 210 Electron gun 211 Irradiation lens 212 Deflector 214 Sample stage 216 Objective lens 217 Intermediate lens 218 Projection lens 220 Detector 230 Peltier element power supply

Claims (5)

A sample holder for a charged particle beam device,
a Peltier element having a heat dissipation surface and a heat absorption surface;
a first heat conducting member connected to the heat dissipation surface;
a sample holder that is connected to the first thermally conductive member and holds a sample;
a second heat conducting member connected to the heat absorbing surface;
a cold trap connected to the second thermally conductive member;
including a sample holder. In claim 1,
A sample holder, wherein the cold trap surrounds the sample holder. In claim 1 or 2,
A sample holder, wherein the cooling trap is provided with a first through hole through which the charged particle beam irradiated to the sample passes, and a second through hole through which the charged particle beam that has passed through the sample passes. A charged particle beam device comprising the sample holder according to any one of claims 1 to 3. In claim 4,
including a power supply that supplies power to the Peltier element;
the sample holder includes a connector;
A charged particle beam device, wherein the power is supplied from the power source to the Peltier element via the connector.

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