JP2001074621A - Manufacture of sample for electron microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily adhere a sample on a metal mesh without breaking an organic film adhered on the mesh without breaking the sample for an electron microscope or without flying and losing the sample. SOLUTION: The method for manufacturing a sample for an electron microscope comprises the steps of forming water droplets 21 made of a pure water on a support base 18 made of a metal mesh 17 in which a collodion film 16 is spread on its surface, adhering the sample 15 to an end of an electrostatic pincette 14 to collect the sample 15, bringing the sample into contact with the droplets 21 to dispose the sample 15 on the base 18, and adhering the sample.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing a transmission electron microscope (TEM) observation sample, which is attached to a support member made of a metal mesh.

[0002]

2. Description of the Related Art When examining a crystal structure of a semiconductor wafer or the like, a sample 15 is formed by digging a semiconductor wafer using a focused ion beam system (FIB), and an electrostatic tweezer 14 is formed as shown in FIG. The sample 15 is collected by attaching the sample 15 to the tip of the sample, and the sample 15 thus collected is attached to a thin organic film, for example, a metal mesh 17 on which a collodion film 16 is stretched. Observation with a scanning electron microscope.

[0003]

By the way, conventionally,
Since the sample 15 attached to the electrostatic tweezers 14 is directly stuck on the metal mesh 17 on which the collodion film 16 is stretched, the following problems occur.

[0004] First, the electrostatic tweezers 14
When the suction force due to the static electricity is strong, even if the sample 15 touches the metal mesh 17, the sample 15 does not separate from the electrostatic tweezers 14 and does not stick to the metal mesh 17.

[0005] Second, as shown in FIG. 10, when the sample 15 is stuck on the upper side of the electrostatic tweezers 14, the position of the electrostatic tweezers 14 is manually adjusted so that the sample 15 is on the metal mesh 17 side. I need to change. At this time, there is a risk that the sample 15 may be destroyed or may be lost by flying.

Third, as shown in FIG. 11, when the sample 15 stands upright with respect to the surface of the metal mesh 17, the collodion film 1 on the surface is adhered when the sample 15 is attached.
I break 6 and can't stick it.

The present invention has been made in consideration of the above circumstances, and has as its object to prevent the sample from being destroyed or flying away from being lost, and to provide an organic film stretched on a metal mesh. An object of the present invention is to provide a method for preparing a sample for an electron microscope, which can easily adhere a sample on a metal mesh without breaking the sample.

[0008]

According to a method for preparing a sample for an electron microscope of the present invention, a volatile liquid is applied in advance to a support made of a metal mesh having an organic film stretched on its surface, and an electrostatic charge is applied to the support. A sample is collected by attaching the sample to the tip of the tweezers, and the sample is placed on the support base by bringing the collected sample into contact with the liquid, so that the sample is adhered. I do.

In the method of preparing a sample for an electron microscope according to the present invention, the sample is collected by attaching the sample to the tip of an electrostatic tweezer having a hollow portion for supplying a liquid, and the sample is collected through the hollow portion of the electrostatic tweezer. Supplying a volatile liquid toward the tip, placing the sample on a support by dropping the sample together with the liquid on a support made of a metal mesh with an organic film stretched on the surface, It is characterized in that it is adhered.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described by way of embodiments with reference to the drawings.

First, a method for manufacturing a sample for an electron microscope according to the first embodiment will be described. For example, when examining the crystal structure of a semiconductor wafer, a sample is prepared as follows. First, FIB (Focused Ion Beam system)
The semiconductor wafer 10 is etched such that two rectangular holes 12 and 13 are formed adjacent to each other via a sample portion 11 having a width of 0.1 μm as shown in the plan view of FIG. Perform processing.

Next, as shown in the plan view of FIG. 2, electrostatic tweezers 14 made of, for example, glass and processed to have a tip portion having a diameter of, for example, 4 to 6 μm are placed on the sample portion 1.
The sample portion 11 is separated from the original semiconductor wafer 10 by pressing against the side surface of the semiconductor wafer 10. At this time, the electrostatic tweezers 14 are charged in advance, and the sample portion 11 separated from the original semiconductor wafer 10 adheres to the tip of the electrostatic tweezers 14,
Thereby, the sample 15 is collected. This sample 15
The thickness is 0.1 μm of the original width, and the length of the long side is 10 μm, for example.
m, the length of the short side is, for example, 7 to 7 of the thickness of the semiconductor wafer 10.
It is a small piece of 8 μm.

On the other hand, as shown in the plan view of FIG. 3, a support base 18 made of a metal mesh 17 having a collodion film (organic film) 16 having a thickness of, for example, 0.1 μm or less is prepared. . The metal mesh 17 has a plurality (see FIG. 3).
In this case, 16 openings 18 are provided, and a sample to be observed is placed on the collodion film 16 at a position corresponding to each of the openings 18. Thus, the collodion film 16
A support 18 made of a metal mesh 17 having a surface stretched
Is generally used as an observation support on which a sample is placed and adhered when observing a metal, a biological cell, or the like with a transmission electron microscope.

Then, as shown in the sectional view of FIG. 4, after mounting the support base 18 on the slide crow 20, a volatile liquid such as pure water is applied to the surface of an organic film, for example, the collodion film 16. I do. For this application, for example, pure water is sprayed by spraying or the like, and the opening 1
This is performed by forming minute water droplets 21 made of pure water on the surface of the collodion film 16 at a position corresponding to 9.

Next, as shown in the cross-sectional view of FIG. 5, the electrostatic tweezers 14 having the sample 15 attached to the tip end are moved to the position of the water droplet 21 on the surface of the collodion film 16 and the sample 1 is moved.
5 is brought into contact with the water droplet 21. Thereby, the static electricity charged on the electrostatic tweezers 14 is released, and the sample 15 floats on the surface of the water droplet 21.

Thereafter, as the water droplets 21 evaporate spontaneously, the sample 15 adheres to and adheres to the surface of the collodion film 16 as shown in the sectional view of FIG.

Thereafter, the support table 18 is moved to the position of the transmission electron microscope to observe the sample.

As described above, according to the method for manufacturing a sample according to the above-described embodiment, the static electricity charged on the electrostatic tweezers 14 is released when the sample 15 comes into contact with the surface of the water droplet 21. Even when the suction force is strong, the sample 15 can be reliably separated from the electrostatic tweezers 14. As a result, the sample 15 can be securely bonded onto the metal mesh 17.

Further, even when the sample 15 is stuck on the upper side of the electrostatic tweezers 14 as shown in FIG. 10, the static electricity is removed when the tip of the electrostatic tweezers 14 comes into contact with the surface of the water droplet 21. Sample 15
Can be dropped on the surface of the water droplet 21. Therefore, there is no need to manually change the position of the electrostatic tweezers 14 as in the related art, and the sample 15 may be destroyed,
There is no risk of being lost by skipping.

Further, as shown in FIG.
When the sample stands upright with respect to the surface of the metal mesh 17, the sample 15 first contacts the water droplet 21 and then is dropped onto the surface of the water droplet 21. There is no danger of breaking.

In the above embodiment, the case where pure water is applied to the surface of the collodion film 16 has been described.
This may be any liquid as long as it can be volatilized, and for example, alcohol or organic solvent can be used in addition to pure water. Further, in the above-described embodiment, the case where the organic film on the metal mesh 17 is the collodion film 16 has been described. However, another organic film such as a formvar film or a triacetyl cellulose film may be used. .

Next, a method of manufacturing a sample for an electron microscope according to a second embodiment of the present invention will be described. The method for collecting a sample is the same as that in the first embodiment, and a description thereof will be omitted. However, in this embodiment, the electrostatic tweezers 14 having a hollow portion 31 as shown in the sectional view of FIG. 7 is used. Then, in the same manner as described above, the electrostatic tweezers 14 are charged in advance when collecting the sample. FIG. 7A shows a state in which the sample 15 has adhered to the tip of the charged electrostatic tweezers 14. Next, the electrostatic tweezers 14 is moved to a position on the collodion film 16 of the support base 18, and as shown in FIG.
A volatilizable liquid such as pure water is supplied to the distal end portion through 1. As a result, the sample 15 is hung below the water droplet 21 made of pure water curled by surface tension,
In this state, a water droplet 21 is dropped on the collodion film 16 together with the sample 15 as shown in the sectional view of FIG. After the drop, the sample 15 floats on the surface of the water droplet 21.

Thereafter, as the water droplets 21 evaporate spontaneously, the sample 15 adheres to and adheres to the surface of the collodion film 16 as shown in the cross-sectional view of FIG.

As described above, according to the method for manufacturing a sample according to the above-described embodiment, since the sample 15 is dropped together with the water droplet 21, even if the suction force of the electrostatic tweezers 14 is strong, the sample 15 can be securely removed from the electrostatic tweezers 14. Can be separated. As a result, the sample 15 can be securely bonded to the metal mesh 17.

Also, even when the sample 15 is stuck on the upper side of the electrostatic tweezers 14 as shown in FIG. 10, water droplets 21 are formed at the tip of the electrostatic tweezers 14 and the sample 15 Since it is hung below the water droplet 21, there is no need to manually change the position of the electrostatic tweezers 14 as in the related art, and there is no possibility that the sample 15 will be destroyed or fly away.

Further, as shown in FIG.
Even when the sample stands vertically with respect to the surface of the metal mesh 17, a water droplet 21 is formed at the tip of the electrostatic tweezers 14, and the sample 15 hangs below the water droplet 21. Since the sample 15 is dropped onto the collodion film 16 together with the water droplet 21, there is no possibility that the collodion film 16 is broken unlike the conventional case.

In the above embodiment, the case where pure water is supplied to the tip of the electrostatic tweezers 14 through the hollow portion 31 has been described. For example, an alcohol or an organic solvent may be used in addition to pure water. Further, in the above-described embodiment, the case where the organic film on the metal mesh 17 is the collodion film 16 is described, but another organic film, for example, a formvar film or a triacetyl cellulose film may be used. .

[0028]

As described above, according to the present invention,
A method for preparing a sample for an electron microscope that can easily adhere a sample to a metal mesh without breaking the sample or losing the sample by flying, and without breaking an organic film stretched on the metal mesh. Can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view when a sample is manufactured by processing a semiconductor wafer.

FIG. 2 is a plan view showing a state in which the sample is separated from a semiconductor wafer and a sample is collected.

FIG. 3 is a plan view showing a support base used in the present invention.

FIG. 4 is a cross-sectional view showing a state in which a liquid is applied to the surface of a collodion film after a support base is placed on a slide crow in the method of the first embodiment.

FIG. 5 is a cross-sectional view showing a state where a sample is placed on the surface of the collodion film of the support in the method according to the first embodiment.

FIG. 6 is a cross-sectional view showing a state where the sample is adhered to the surface of the collodion film of the support in the method according to the first embodiment.

FIG. 7 is a sectional view showing an electrostatic tweezer used in the method of the second embodiment and a state in which a liquid is supplied to the tip of the electrostatic tweezer.

FIG. 8 is a cross-sectional view showing a state where a sample is placed on the surface of a collodion film of a support in the method according to the second embodiment.

FIG. 9 is a cross-sectional view for explaining a conventional method.

FIG. 10 is a cross-sectional view for explaining a conventional method.

FIG. 11 is a cross-sectional view for explaining a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Semiconductor wafer, 11 ... Sample part, 12 and 13 ... Square hole, 14 ... Electrostatic tweezers, 15 ... Sample, 16 ... Collodion film (organic film), 17 ... Metal mesh, 18 ... Support base, 19 ... Opening Reference numeral 20: slide crow, 21: water drop, 31: hollow part.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Naohisa Suzuki 25-1, Ekimae Honcho, Kawasaki-ku, Kawasaki-ku, Kanagawa Prefecture F-term (reference) 2G001 AA03 BA11 CA03 GA01 GA06 GA09 HA09 HA13 JA12 KA08 LA11 MA05 RA08 RA10 4M106 AA01 AA20 BA02 BA12 CB17 DH24 DH55 DH60 DJ02 DJ32

Claims (7)

[Claims] 1. A volatilizable liquid is applied in advance to a support made of a metal mesh having an organic film stretched on its surface,
A sample is collected by attaching the sample to the tip of the electrostatic tweezers, and the sample is placed on the support by bringing the collected sample into contact with the liquid,
A method for manufacturing a sample for an electron microscope, wherein the sample is bonded. 2. The method for preparing a sample for an electron microscope according to claim 1, wherein the volatile liquid is applied by spraying onto the support base. 3. The method for preparing a sample for an electron microscope according to claim 1, wherein the volatilizable liquid is any one of pure water, alcohol, and an organic solvent. 4. The method for producing a sample for an electron microscope according to claim 1, wherein the organic film is any one of a collodion film, a formvar film, and a triacetyl cellulose film. 5. A sample is collected by attaching a sample to the tip of an electrostatic tweezer having a hollow portion for supplying liquid, and a liquid that can be volatilized toward the tip portion through the hollow portion of the electrostatic tweezer. The sample is placed on the support by supplying and dropping the sample together with the liquid on the support made of a metal mesh having an organic film stretched on the surface, and the sample is placed and adhered. Method for preparing electron microscope sample. 6. The method for preparing a sample for an electron microscope according to claim 5, wherein the volatilizable liquid is any one of pure water, alcohol, and an organic solvent. 7. The method for producing a sample for an electron microscope according to claim 5, wherein the organic film is any one of a collodion film, a formvar film, and a triacetyl cellulose film.