JP2003294594A - Tissue sample formation method, tissue sample formation device, and jig for forming electron microscopic sample - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and the like for forming a tissue sample by a simple method while increasing packing density of powder particles. <P>SOLUTION: This tissue sample formation method comprises a mixing process (step S101) for producing a mixture of powder and resin and a pressurizing process (step S102) for applying a pressure to the mixture to turn it into a thin piece. In the mixing process, when a ratio (volume ratio) of the resin to the powder is set to 2 or more, density of the powder can be increased. In the pressurizing process (step S102), the mixture can have an area with a film thickness of 20 μm or less. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a thin sample for observing powder, and more specifically,
The present invention relates to a method for producing a thin sample suitable for observing the inside of powder particles with a transmission electron microscope.

[0002]

2. Description of the Related Art Conventionally, as a method for preparing a sample for a transmission electron microscope (TEM) for a powdery sample, a method of dispersing and fixing the powder on a sheet mesh having an organic thin film has been disclosed ( JP-A-52-89372,
See Japanese Patent Laid-Open No. 2-262226). In recent years, G
A focused ion beam (FIB) processing observation device (hereinafter referred to as "FIB device") that can thin a desired part of an object by a-ion irradiation was developed, and a thin film of powder particles by the FIB device was developed. Samples for electron microscope observation have been produced by crystallization.

However, in the methods described in JP-A-52-89372, JP-A-2-262226, etc., since the powder which is dispersed and fixed is observed as it is, the particle size of the powder sample is as small as about 100 nm or less. Structural analysis was possible only in the very thin part of the end of the powder particle, which was either small or permeable to electron beams. This is because the electron beam is not sufficiently transmitted by a commonly used TEM unless the size of the powder sample is about 100 nm or less.
Further, when thinning the powder particles by the FIB device, it is difficult to control the thinning, the powder sample may be damaged, and the processing area is 10 μm × 10 μm.
There are problems such as being limited to about m. Moreover, FI
The B device is very expensive. Therefore, Japanese Patent Laid-Open No. 7-209
No. 155, etc., that is, a method in which a powder is embedded in a resin and a mixture of the resin and the powder is subjected to mechanical polishing and ion polishing to produce a thin section of the powder is a powder. It is being widely used as a method for producing a sample. Here, FIG. 9 shows a sample preparation procedure in the case of TEM observation of a powder sample thinned by mechanical polishing and ion polishing.

As shown in FIG. 9, first, powder is mixed with resin (step S201), and the bulk mixture is solidified and dried (step S202). Then, this bulk material is, for example, 50 μm
Cut out to an appropriate thickness of about 100 μm (step S2
03), and then mechanically polishing the cut-out sample (step S204). Subsequently, the sample that has been mechanically polished is subjected to ion polishing by a milling device (step S205) to reduce the thickness of the sample to 100 nm or less, and then TEM observation is performed.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In order to manufacture a TEM sample by the method described in Japanese Patent Publication No. 09155, it is desirable to prepare a site having a sample thickness of about 10 μm to 20 μm before ion polishing (step S205). Therefore, the mechanical polishing in step S204 described above is composed of a plurality of steps. Usually, a sample cut out to a size of about 50 μm to 100 μm is first rough-polished, and then it is 3 mmφ with a disc punch or an ultrasonic disc cutter. It is punched out, then further precision polished and polished with a dimple grinder. As described above, since it takes a lot of time and effort to perform mechanical polishing (step S204) of the sample cut out, it is usual to complete mechanical polishing (step S204) of the sample cut out from the cut out (step S203). Took about 5 hours. Further, when mechanically polishing a bulk mixture of powder and resin, excessive stress is applied to the powder, and this stress may cause process deterioration of the powder. That is, in the conventional method, it is often necessary to observe the powder in a state in which the work is deteriorated, which sometimes hinders precise observation of the powder structure. Further, bubbles often remain in the bulk mixture of the powder and the resin, which may hinder mechanical polishing or ion polishing. Therefore, it is necessary to separately perform defoaming treatment.
Furthermore, in the bulk mixture formed by the conventional method, in order to increase the density of the powder to be observed, the absolute amount of the powder sample required increases. Therefore, it is an object of the present invention to provide a method for producing a thin sample by a simpler method and the like.

[0006]

Conventionally, since it was premised that mechanical polishing was performed prior to ion polishing, the mixture was formed in a bulk shape or a thick plate shape. The present inventor has noticed that it is extremely effective to prepare a flaky mixture in advance in order to omit or reduce this mechanical polishing. Then, they found that a flaky sample can be obtained by a simple method of applying pressure to the mixture. That is, the present invention is a method for producing a thin sample for observing powder, which comprises a mixing step of obtaining a mixture of powder and a resin, and a pressurization for applying pressure to the mixture to form a thin piece. And a step for preparing a thin sample. In the mixing step, the density of the powder can be increased by setting the ratio (volume ratio) of the powder to the resin to 2 or more. Further, according to the thin sample preparation method of the present invention, it is possible to prepare a thin sample suitable for observation even when only a small amount of powder sample is obtained.

Further, according to the thin sample preparation method of the present invention, the mixture is formed into an arbitrary shape in the above-mentioned pressing step.
For example, it becomes possible to form an arbitrary pattern on the sample surface and control the film thickness within an arbitrary range. Specifically, in the pressing step, the mixture can have a region with a film thickness of 20 μm or less. The method for producing a thin sample according to the present invention may further include an ion polishing step of performing ion polishing on the thin sample in the state obtained in the pressing step. It is effective to perform this ion polishing on a region having a film thickness of 20 μm or less.
This is because it is inefficient and unrealistic to perform ion polishing on the entire thin sample. According to the thin sample preparation method of the present invention, since a site having a region having a film thickness of 20 μm or less is prepared in advance in the pressurizing step, mechanical polishing as preliminary polishing that has been conventionally performed before ion polishing. Can be omitted.

The present invention also provides a novel thin sample preparation device having the following constitution. That is, the thin sample preparation device according to the present invention is a device for preparing a thin sample by curing a mixture of powder and resin, and sandwiching the mixture,
It is characterized by comprising a thinning means for thinning the mixture and a resin curing means for curing the resin in a state where the mixture is pressurized. Here, as the thinning means, for example, a plate-shaped member made of glass or the like can be used. Further, in the thin sample preparation apparatus according to the present invention, by providing the difficult-to-adhere layer in the contact area between the thinning means and the mixture, it is possible to effectively prevent the thin sample after curing from adhering to the thinning means. be able to. The difficult-to-adhere layer can be formed using polytetrafluoroethylene (trade name: Teflon (trademark)) or the like, which makes it difficult for the resin to adhere. When the above-mentioned resin is a thermosetting resin, the resin curing means can be a heating body that is heated and held at a temperature higher than the temperature at which the thermosetting resin cures. Further, the present invention is provided with a pressure plate having at least one of transparent powder and resin sandwiching the electron microscope sample, and a difficult adhesion layer provided on a part or all of the surface of the pressure plate. A sample preparation jig for an electron microscope is provided. As the pressing plate, for example, a glass plate can be used. The difficult-to-adhere layer may be formed by applying a Teflon coat to the pressure plate, or may be formed by adhering a Teflon sheet to the pressure plate.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the present invention is a method for preparing a thin sample, in which a mixture of resin and powder is obtained, and then pressure is applied to the mixture to form a thin piece. A feature is that a thin sample is prepared by a simple method. An embodiment of the present invention will be described below with reference to the drawings.

First, the powder and resin constituting the sample will be described. As the powder, one whose inside is desired to be observed may be appropriately selected. For example, it is possible to select ceramics particles such as BaTiO _3, solder particles, such as Sn-Ag, Ni powder, such as glass particles, a wide variety of things. It is preferable to use a powder having a diameter of micron size or smaller. in this case,
This is because it becomes possible to omit the mechanical polishing that was conventionally required before the ion polishing.

As the resin mixed with the powder, a thermosetting resin, a photocurable resin or the like is used. Among them, the thermosetting resin has a reduced viscosity when heated to about 100 ° C., so that the powder and the resin can be easily mixed by the time curing begins, and bubbles are unlikely to remain. Therefore, the ratio of the powder to the resin can be increased, which is preferable. Here, examples of the thermosetting resin include epoxy resins, phenol resins, melamine resins, etc. Epoxy resins, which are characterized by being relatively fast against electron beams, are particularly preferable. preferable. In addition, photocurable resins are generally monomers, oligomers, photopolymerization initiators, various additives (stabilizers, fillers, pigments, etc.)
The composition is composed of

One feature of the present embodiment is that the ratio of powder to resin (volume ratio) can be set to 2 or more even when only a small amount of powder can be used for observation. By setting the ratio (volume ratio) of the powder to the resin to 2 or more, the powder density in the sample can be significantly increased as compared with the conventional one, and the powder per observation area can be observed even by TEM. It is possible to increase the number of particles. Therefore, it becomes possible to obtain sufficient information on the powder particles. The ratio of powder to resin (volume ratio) is
Although it varies depending on the type of resin, the size of powder, etc., it is effective to set the ratio of powder to resin (volume ratio) to 2 or more and 8 or less, further 3 or more and 8 or less, and more desirably 5 or more and 8 or less. is there. In order to increase the powder density in the sample, it is preferable to increase the ratio of powder to resin (volume ratio) as much as possible. Therefore, the ratio of powder to resin (volume ratio)
Is 2 or more. On the other hand, when the ratio of the powder to the resin (volume ratio) exceeds 8, the amount of the resin functioning as an embedding agent for fixing the powder decreases, so that it becomes difficult to prepare a thin sample. Therefore, the ratio of powder to resin (volume ratio) is 8 or less. In the following, the present embodiment will be described by taking a case where a thermosetting resin is used as the resin mixed with the powder.

FIG. 1 is a diagram showing an example of the configuration of a sample preparation apparatus according to this embodiment. FIG. 2 is a diagram schematically showing the configuration of the sample preparation device according to the present embodiment, and is also a diagram for explaining the hardly-adhesive layer formed on the transparent member. FIG. 3 is a view showing a state in which a mixture of resin and powder is pressed into a state of being sandwiched between two transparent members and made into a thin piece. As shown in FIGS. 1 to 3, the sample preparation device 100 according to the present embodiment holds a mixture 10 of powder and a thermosetting resin and thins the mixture 10. It is composed of a charging means, a pressing plate) 1a, a transparent member (thinning means, a pressing plate) 1b, and a table heater (resin hardening means, heating body) 2 for hardening the resin.

As the transparent members 1a and 1b, for example, flat glass slides can be used. As described above, when the mixture 10 is pressed while being sandwiched between the transparent member 1a and the transparent member 1b, the mixture 10 is thinly stretched and thinned as shown in FIG. In order to easily take out the thinned sample from this state, as shown schematically in FIG. 2, the transparent member 1a and the transparent member 1b are provided with the difficult-to-adhere layer 3 on one surface thereof.

The difficult-to-adhere layer 3 is provided to make it easy to peel off the sample thinned by pressure, and is made of a material such as polytetrafluoroethylene (trade name: Teflon) which is hard to adhere to the resin. Is formed by using.
Specifically, one side of the transparent member 1a and the transparent member 1b,
Specifically, the difficult-to-adhere layer 3 can be formed by adhering a sheet made of polytetrafluoroethylene or coating it with polytetrafluoroethylene in a region where the mixture 10 contacts.

By using a transparent member as the thinning means, it is possible to easily visually confirm the state of the mixture 10 under pressure. That is, the film thickness of the mixture 10 can be determined from the hue of the mixture 10 observed through the transparent member 1a, and it can be easily confirmed whether or not bubbles are present in the mixture 10. be able to.

In this embodiment, the transparent member 1a and the transparent member 1b are used as the thinning means, but the transparent member 1b placed on the table heater 2 is not transparent but colored. You may use. This is because it is sufficient that at least the transparent member 1a is transparent for the above purpose such as visually confirming the state of the mixture 10 under pressure.

The table heater 2 is kept at a temperature at which a resin, specifically, a thermosetting resin is cured. For example,
When using an epoxy thermosetting resin as the resin,
The temperature of the table heater 2 may be set to about 100 ° C to 200 ° C. Note that when a sample is manufactured using the sample manufacturing apparatus 100 according to this embodiment, it is not necessary to perform vacuum deaeration.

Next, a method of preparing a sample according to this embodiment will be described with reference to FIGS. 4 and 5. FIG. 4 is a flowchart showing manufacturing steps of the sample manufacturing method according to the present embodiment. 5 (a) and 5 (c) are diagrams schematically showing a side cross section of the mixture 10 obtained in the mixing step (step S101), and FIGS. 5 (b) and 5 (d) are pressurizing steps. It is the figure which showed typically the side cross section of the thin sample 20 obtained by (step S102).

As shown in FIG. 4, in the sample manufacturing method according to the present embodiment, a mixing step (step S101), a pressurizing step (step S102), a sample cutting step (step S103), and an ion polishing step (step S104). ) Is provided. However, the essential steps for obtaining the thin sample 20 are the mixing step (step S101) and the pressurizing step (step S102), and the sample cutting step (step S103) and the ion polishing step after the pressurizing step (step S102). (Step S104) is an arbitrary process. That is, when the thin piece sample 20 is used as a TEM sample, it is necessary to perform the sample cutting step (step S103) and the ion polishing step (step S104).
When 0 is not a TEM sample but an optical microscope sample or the like, the sample cutting step (step S103) and the ion polishing step (step S104) can be omitted. Hereinafter, each step will be described in detail.

<Mixing Step (Step S101)> In the mixing step (step S101), the powder is kneaded into the resin and mixed to obtain a mixture 10. The mixing ratio of the powder and the resin at this time is, as described above, the ratio of the powder to the resin (volume ratio) is 2 or more and 8 or less, preferably 5 or more and 8 or less. Here, the state of the mixture 10 obtained in the mixing step (step S101) is schematically shown in FIG.

As shown in FIG. 5A, since the amount of the powder with respect to the resin is large, the resin is present in some places so as to fill the space between the powders. Further, since air is contained in the resin during mixing, air bubbles are present in part of the mixture 10.

<Pressurizing Step (Step S102)> In the subsequent pressing step (step S102), an appropriate pressure is applied to spread the mixture 10 into a thin piece. Specifically, as shown in FIGS. 2 and 3, the transparent member 1b is placed on the table heater 2 and a spatula or the like is used on the difficult-to-bond layer 3 formed on the transparent member 1b in step S101. The resulting mixture 10 is applied. At this time, the table heater 2
At a temperature at which the thermosetting resin is further softened, for example 100
It is desirable to keep the temperature at about 120 to 120 ° C. Then, by further maintaining the heated state, the thermosetting resin mixed with the powder is solidified. The temperature and the holding time for this purpose may be appropriately selected according to the thermosetting resin used. Next, the transparent member 1a is placed on the transparent member 1b with the surface provided with the difficult-to-adhere layer 3 facing downward,
The mixture 10 is thinly stretched between the two transparent members 1a and 1b, and pressure is applied from above and below to obtain a thin sample 20 as shown in FIG. 5B. The pressing method is not particularly limited, and the pressure may be applied by human hands or the like. The standard of the pressing force is such that the mixture 10 extends thinly and almost no bubbles remain in the mixture 10. Further, the film thickness of the mixture 10 is a desired thickness, for example, 2
The pressing force is appropriately adjusted so as to be 0 μm or less. In addition, the film thickness of the mixture 10 does not necessarily need to be uniform, and it is sufficient that a part thereof has a film thickness of 20 μm or less.

Further, according to the pressurizing step according to the present embodiment, not only the thin piece sample 20 having a substantially uniform thickness as shown in FIG. 5B, but also as shown in FIG. It is also possible to produce a thin sample 20 having a thickness that is continuously changed. In this case, a spacer (not shown) for controlling the gap may be provided between the lower surface of the transparent member 1a and the upper surface of the transparent member 1b, and the pressure may be applied so that the gap is inclined. This makes it possible to reliably obtain the desired thickness of the thin sample 20.

Further, as shown in FIG. 6 (b), when the mixture 10 is sandwiched between the transparent members 1a and 1b, the thin sample 2 is used by utilizing the bending of the transparent member 1a.
At 0, it is possible to surely obtain a portion having a desired thickness. Further, as shown in FIG. 6C, the gap between the lower surface of the transparent member 1a and the upper surface of the transparent member 1b is arbitrarily set by using, for example, a spacer, thereby facilitating the thin sample 20 having a desired thickness. It is also possible to fabricate.

As another application example, as shown in FIG. 7 (a), a groove is formed on the lower surface of the transparent member 1a to have an arbitrary thickness,
You may make it produce the thin sample 20 of arbitrary shapes. Although FIG. 7A illustrates the case where the groove is formed on the lower surface of the transparent member 1a, the groove may be formed on the upper surface of the transparent member 1b, or the lower surface of the transparent member 1a and the transparent member 1a. Of course, it is also possible to form grooves on both upper surfaces of 1b.

Further, as shown in FIG. 7B, by providing a convex projection on one surface of the transparent member 1a or the transparent member 1b, a concave groove is transferred to the thin sample 20 side. Good. By providing such a groove, it is possible to easily cut out the thin sample 20 in a sample cutting step (step S103) described later. In addition, as shown in FIG. 7C, depending on the height of the convex protrusion provided on one surface of the transparent member 1a or the transparent member 1b and the thickness of the thin piece sample 20, it is attached to a TEM mesh (diameter 3 mmφ) described later. The shape can be easily attached. That is, the height of the convex protrusions provided on one surface of the transparent member 1a or the transparent member 1b and the thickness of the thin sample 20 are set so that the thickness corresponding to the groove portion formed in the thin sample 20 is minimized. It may be set so that a tear line that can be easily broken by hand may be formed on the thin sample 20.

According to the pressurizing method in this embodiment,
In the case of anisotropic particles in which the particle shape is selectively extended in a certain crystal direction as shown in FIG. 5C, the direction in which the powder is embedded in the resin can be controlled to some extent. For example, when the mixture 10 shown in FIG. 5C is pressed by the pressing method according to the present embodiment, the powder can be embedded in the resin in the state shown in FIG. 5D.

By the heat from the table heater 2,
The thermosetting resin forming the mixture 10 can be cured in about 1 to 10 minutes, but it is preferable to heat the cured mixture 10 for about 10 minutes. By performing this heating, it is possible to obtain the thin sample 20 having high strength and easy to handle. The heating after the thermosetting resin is cured may be performed at about 150 ° C to 200 ° C.

Incidentally, as described above, the mixture 1 under pressure.
The film thickness of 0 and the presence or absence of bubbles can be visually observed through the transparent member 1a. Therefore, the pressurizing step (step S
In 102), while observing the state of the mixture 10 through the transparent member 1a, if the mixture 10 is pressed until the bubbles are removed, the defoaming process should be performed during the pressurizing step (step S102). You can Therefore, it is possible to omit the defoaming step which has conventionally been performed for removing bubbles in the bulk mixture of resin and powder.

As described above, the mixing step (step S1
01) and the subsequent pressurizing step (step S102)
It is possible to easily obtain the thin sample 20 in which a region having a film thickness of 20 μm or less, further 10 μm or less is present by passing through only the above. The thin sample 20 thus obtained is
As shown in FIG. 5B, there are few bubbles that hinder the ion polishing, and the powder density is high. Specifically, the densification of the powder is achieved to the extent that the particles come into contact with each other. Further, by thinning the mixture 10 while sandwiching it between the plate-shaped transparent member 1a and the transparent member 1b, it is possible to greatly improve the flatness of the obtained thin sample 20 as compared with the conventional case.

<Sample cutting step (step S103)
> When the thin sample 20 is used as a TEM observation sample, the process proceeds to the sample cutting step (step S103). In this sample cutting step (step S103), step S1
The thin sample 20 obtained in No. 02 is cut into a size for TEM sample. This cutting operation can be performed using, for example, a knife. Sample cutting process (step S10
The contents of 3) are schematically shown in FIG.

First, as shown in FIG. 8A, a portion of the thin sample 20 to be used is selected. As described above, in the present embodiment, the transparent member 1a and the transparent member 1
Since the technique of sandwiching and pressing the mixture 10 between b is adopted, the thin sample 20 can have any thickness and shape. Therefore, a portion having a desired thickness in the thin sample 20 is The site to be used can be arbitrarily selected. Next, as shown in FIG. 8B, the thin piece sample 20 is cut so as to include a portion to be used, and further cut into a desired size as shown in FIG. 8C. Since the area of the thin piece sample 20 is larger than the area that can be processed at one time by using the FIB device, a plurality of portions is selected from one thin piece sample 20 as a portion to be used and one portion is selected. It is also possible to cut out a plurality of TEM samples from the thin sample 20.

Here, a TEM sample having a diameter of 3 mmφ is usually used. Therefore, the thin sample 20
May be directly cut into 3 mmφ to be used as a TEM sample, or its outer diameter is 3 mm as shown in FIG. 8 (d).
A single-hole portion of a φ single-hole mesh (so-called TEM mesh) is cut out as shown in FIG. 8C, for example, 2 mm.
A rectangular sample of about × 2 mm may be bonded to the hole portion of the single-hole mesh with a resin or the like to be used as a TEM sample.

<Ion Polishing Step (Step S104)>
In the subsequent ion polishing step (step S104), ion polishing is performed on the thin sample 20 using a known milling device. The time required for this ion polishing process is about 1 to 2 hours, although it depends on the size of the sample cut out. For ion polishing, Ar ions or the like can be usually used. Through the ion polishing step (step S104), the thin sample 20 has a thickness of 100 nm or less, and can be used as a TEM observation sample.

By passing through the above step S104, the thin sample 20 suitable for the TEM sample can be easily manufactured. Unlike the conventional method, in order to thin the mixture 10 in the pressing step (step S102),
According to the sample preparation method of this embodiment, the mechanical polishing step can be omitted when processing micron-order powder, and as a result, the time required for TEM sample preparation can be reduced by about 5 hours. Is possible. in this way,
Not only the TEM sample can be produced in a relatively short time, but also by omitting the mechanical polishing step, distortion and alteration of the powder, which is caused by mechanical polishing, that is, so-called process alteration, is reduced. Therefore, it is possible to observe the inside of the powder sample in a state in which the processing deterioration is significantly smaller than that in the conventional method, and thus the observation accuracy is improved.
Furthermore, by changing the mixing ratio of the powder and the resin so that the amount of the powder is at least twice that of the resin, the density of the powder is increased and the number of powder particles per observation area is increased. It becomes possible to do. Further, even when only a small amount of powder sample can be obtained, the thin sample 20 suitable for observation can be manufactured.

[0037]

As described in detail above, according to the present invention,
It is possible to increase the packing density of the powder particles and to prepare a thin sample by a simpler method.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a configuration of a sample preparation device according to the present embodiment.

FIG. 2 is a diagram schematically showing a configuration of a sample preparation device according to the present embodiment, and is a diagram for explaining a difficult-to-adhere layer formed on a transparent member.

FIG. 3 is a view showing a state in which the mixture is pressed into a state of being sandwiched between two transparent members and made into a thin piece.

FIG. 4 is a flowchart showing manufacturing steps of the sample manufacturing method according to the present embodiment.

5 (a) and 5 (c) are side sectional views of the mixture obtained in the mixing step (step S101), FIG. 5 (b),
(D) is a side sectional view of a thin sample obtained in the pressing step (step S102).

FIG. 6 is an explanatory diagram in the case of manufacturing a thin piece sample having an arbitrary thickness and shape in a pressing step (step S102).

FIG. 7 is an explanatory diagram of a case where a thin piece sample having an arbitrary shape is produced in a pressing step (step S102).

FIG. 8 is a diagram schematically showing the content of a sample cutting step (step S103).

FIG. 9 is a flowchart showing manufacturing steps of a conventional sample manufacturing method.

[Explanation of symbols]

1a, 1b ... Transparent member (thinning means, pressure plate), 2 ... Table heater (resin curing means, heating body), 3 ... Difficult adhesive layer, 10 ... Mixture, 20 ... Thin sample, 100 ... Sample preparation device

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Claims (9)

[Claims] 1. A method for producing a thin sample for observing a powder, comprising a mixing step of obtaining a mixture of the powder and a resin, and a pressurization for applying a pressure to the mixture to form a thin piece. A method for preparing a thin sample, comprising: 2. The method for preparing a thin sample according to claim 1, wherein in the mixing step, the ratio (volume ratio) of the powder to the resin is 2 or more. 3. The method for preparing a thin sample according to claim 1, wherein the mixture is formed into an arbitrary shape in the pressing step. 4. The method of preparing a thin sample according to claim 1, wherein, in the pressing step, the mixture has a region having a film thickness of 20 μm or less. 5. The method for producing a thin piece sample according to claim 1, further comprising an ion polishing step of performing ion polishing on the thin piece sample in the state obtained in the pressing step. 6. An apparatus for producing a thin sample by curing a mixture of powder and resin, comprising a thinning means for sandwiching the mixture and thinning the mixture, and the mixture. And a resin curing unit that cures the resin in a pressurized state. 7. The thin sample preparation apparatus according to claim 6, wherein a difficult-to-adhere layer is provided in a contact region between the thinning means and the mixture. 8. The thin sample preparation according to claim 6, wherein the resin is a thermosetting resin, and the resin curing means is a heating body which is heated and held at a temperature higher than a temperature at which the resin is cured. apparatus. 9. A pressure plate, at least one of which is transparent and which holds a powder and a resin constituting a sample for an electron microscope, and a hardly-adhesive layer provided on a part or all of the surface of the pressure plate. A sample preparation jig for an electron microscope.