JPH11337459A - Separation of embedding resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To markedly separate an embedding resin in a non-destructive manner than ever. SOLUTION: A embedding resin separating method is characterized by providing a process immersing a sample 22 covered with an embedding resin 21 excepting a micro-observation surface 23 in TFC 24 so that the resin is immersed in such a state that the observation surface 23 is turned upwardly, a process for separating the greater part of the resin 21 by applying ultrasonic washing to the sample 21, a process for forming an Au vapor deposition film on the resin separating surface of the sample 21, a process for separating the residual resin by immersing the sample 21 in conc. sulfuric acid 32 and a process for removing conc. sulfuric acid 32 bonded to 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 removing embedded resin, and more particularly, to a method for removing embedded resin for removing a resin adhered to a fracture surface of a sample subjected to microstructure observation.

[0002]

2. Description of the Related Art Conventionally, embedding resin is peeled off as shown in FIGS.
This is performed as shown in FIG. First, as shown in FIG. 2 (A), a sample (fracture surface) 3 covered with an embedding resin (fracture surface) 1 except for a micro-observation surface 2 is placed in a LN accommodated in a container 4.
₂ Immerse in the (liquid nitrogen) 5 with the micro observation surface 2 facing upward (see FIG. 2 (B)). Subsequently, after the sample 3 and the embedded resin 1 are sufficiently cooled, the sample 3 and the embedded resin 1 are taken out, and the embedded resin 1 is crushed by sandwiching the vice 6 (see FIG. 2C). Thereafter, the sample 3 is separated from the embedding resin 1 (see FIG. 2D). Note that FIG.
(D) enlarges the fracture surface 7 for convenience. Reference numeral 8 denotes a polished surface, and reference numeral 9 denotes embedded resin residue remaining in the fracture surface 7.
Next, a replica 10 is formed on the fracture surface 7 of the sample 3 to remove the embedded resin residue 9 on the sample 3 (see FIG. 2E). Finally, Au is deposited 11 to form a deposited film 11 (see FIG. 2F).

[0003]

However, according to the prior art, as shown schematically in FIG. 4, the resin remains in the concave portion of the sample 3 and 60% to 40% of the information hidden under the resin is removed. There was a problem that it could not be obtained. In FIG. 4, reference numeral 12 denotes a boundary between the microscopic observation surface 2 and the fracture surface, and all hatched portions 13 indicate the resin remaining portion.

The present invention has been made in view of such circumstances, and a sample covered with an embedding resin except for an observation surface is immersed in a solvent capable of softening the resin with the observation surface facing upward. The sample is subjected to ultrasonic cleaning to remove most of the resin, a film for preventing corrosion is formed on the resin release surface of the sample, and the sample is immersed in an acid solution that is difficult to ionize to remove the remaining resin. An object of the present invention is to provide a method of removing embedded resin, which is capable of non-destructively removing embedded resin as compared with the conventional method by removing acid attached to the sample after peeling.

[0005]

SUMMARY OF THE INVENTION The present invention comprises a step of immersing a sample covered with an embedded resin except for an observation surface in a solvent capable of softening the resin with the observation surface facing upward; Applying ultrasonic cleaning to remove most of the resin, forming a film for preventing corrosion on the resin release surface of the sample, and immersing the sample in an acid solution that is difficult to ionize and remaining A method for removing an embedded resin, comprising: a step of removing a resin; and a step of removing an acid attached to the sample.

In the present invention, the solvent capable of softening the resin includes, for example, tetrahydrofuran. In the present invention, examples of the film for corrosion prevention include a vapor deposition film obtained by vapor deposition of gold. In the present invention, examples of the acid solution that does not easily ionize the sample include concentrated acid.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides the following first to fifth steps.
Process. First step (solvent immersion step): In general, an epoxy resin is used as an embedding resin, but since there is no solvent capable of dissolving the epoxy resin, the resin can be softened, for example, tetrahydrofuran (C ₁₉ H ₂₁₎ N ₇ O ₆ · 3HC
1, hereinafter abbreviated as TFC) for 6 to 7 hours.

Second step (ultrasonic cleaning step): After immersion in TFC, ultrasonic cleaning is performed, for example, for 10 minutes. As a result, TFC enters the gap between the resin and the sample, and the resin swells. Here, when the micro-observation surface is turned downward, 90 to 95% of the concave portions of the fracture surface of the sample fall and peel.

Third step (a step of protecting the resin release surface):
In the third step, in order to prevent the micro observation surface and the peeled surface from being corroded by the concentrated sulfuric acid immersion performed in the next step,
For example, gold is deposited to a thickness of 20 to 40 nm to form an Au deposited film.

Fourth step (acid immersion treatment step): For example, concentrated sulfuric acid hardly ionizes at room temperature and does not corrode the surface, so that it is kept in a refrigerator at 10 ° C. for about 10 minutes to ensure the suppression of ionization. Immerse. As a result, the resin remaining in the recesses is embrittled by the strong dehydration of concentrated sulfuric acid. In addition, when lightly brushed, most of the resin is peeled off as shown in FIG.

Fifth step (neutralization and washing step): When the sample (broken surface) to which concentrated sulfuric acid is adhered is washed with water, sulfuric acid is ionized and causes corrosion. Therefore, in order to prevent corrosion, the sample is washed in a sodium bicarbonate solution, and the oxidizing action of sulfuric acid is eliminated by a neutralization reaction represented by the following formula. 2NaHCO ₃ + H ₂ SO ₄ → Na ₂ SO ₄ + 2H ₂ O
+2 CO ₂ ↑

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIGS.
This will be described with reference to (I). (1) First, as shown in FIG. 1 (A), a sample 22 contained in an embedding resin 21 is placed in a container 25 containing a TFC 24 as a solvent capable of softening the resin with the micro observation surface 23 facing upward. For 6 to 7 hours. Subsequently, the container 25 was placed on the ultrasonic cleaner 26, and the ultrasonic cleaner 26 was operated (see FIG. 1B).

(2) Next, the sample 22 was immersed in a beaker 28 containing alcohol 27, and the resin remaining on the sample 22 was removed as much as possible with an electric toothbrush 29 (see FIG. 1C). Subsequently, the sample 22 was taken out of the alcohol and subjected to gold vapor deposition 30 for the purpose of protecting the exposed metal surface by peeling, thereby forming a gold vapor-deposited film as a film for preventing corrosion (see FIG. 1 (D)). Reference numeral 31 in FIG. 1 (D) indicates an embedded resin residue remaining in the concave portion of the fracture surface of the sample 22.

(3) Next, concentrated sulfuric acid (acid solution in which the sample is not easily ionized) 32 cooled to 10 ° C. in a container 33 is used to peel off the embedded resin remaining in the concave portion of the fracture surface of the sample 22. The sample 22 was immersed in concentrated sulfuric acid 32 for 5 to 10 minutes (FIG. 1).
(E)). Subsequently, after immersion in concentrated sulfuric acid 32, the resin was completely removed by light brushing.

(4) Next, in order to protect the peeled surface, the sample 22 was immersed in the container 34 containing the heavy tank water 34 for 2 to 3 minutes (see FIG. 1 (F)). Subsequently, when the generation of bubbles of carbon dioxide was completed, it was determined that the neutralization reaction was completed, and the sample 22 was quickly taken out, immersed in a beaker 36 containing water 35, and washed with water (FIG. 1 (G)). reference).

(5) Next, a replica 37 was formed to remove dust and dirt attached to the surface of the sample 22 (FIG. 1).
(H)). Next, in order to eliminate evaporation unevenness, sample 22
A finished gold vapor-deposited film was formed on the fracture surface 39 of FIG. 1 and observation was made simultaneously (see FIG. 1 (I)).

According to the above embodiment, since the sample 22 is immersed in the TFC 22 and treated by ultrasonic cleaning, the embedding resin adhering to the sample 22 in a nondestructive manner is significantly reduced (9).
0-95%). On the other hand, in the prior art, in order to separate the embedded resin and the sample, the sample is immersed in liquid nitrogen, sufficiently cooled, and then broken by being sandwiched between vices, so that only about 40 to 60% of the resin can be separated. Was.

In the above embodiment, the case where TFC is used as the solvent capable of softening the resin has been described. However, the present invention is not limited to this, and other materials may be used. Further, concentrated sulfuric acid is used as an acid solution that does not easily ionize the sample, but the present invention is not limited to this, and other materials may be used.

[0019]

As described above in detail, according to the present invention, the sample covered with the embedded resin except for the observation surface is immersed in a solvent capable of softening the resin with the observation surface facing upward, The sample is subjected to ultrasonic cleaning to remove most of the resin, a film for preventing corrosion is formed on the resin release surface of the sample, and the sample is immersed in an acid solution that is difficult to ionize to remove the remaining resin. After peeling, by removing the acid attached to the sample,
It is possible to provide an embedding resin peeling method capable of remarkably peeling the embedding resin in a non-destructive manner as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a method of removing an embedded resin according to an embodiment of the present invention in the order of steps.

FIG. 2 is a flowchart showing a conventional embedding resin peeling method in the order of steps.

FIG. 3 is a schematic diagram when a microscopic observation surface of a sample is observed with a microscope according to the embedding resin peeling method of the present invention.

FIG. 4 is a schematic diagram when a microscopic observation surface of a sample is observed with a microscope according to a conventional embedding resin peeling method.

[Explanation of symbols]

 21: embedded resin, 22: sample, 23: microscopic observation surface, 24: TFC, 26: ultrasonic cleaner, 30, 38: gold deposited film, 32: concentrated sulfuric acid, 37: replica.

Claims (4)

[Claims] 1. A step of immersing a sample covered with an embedding resin except for an observation surface in a solvent capable of softening the resin with the observation surface facing upward; Removing the most part of the sample, forming a film for preventing corrosion on the resin release surface of the sample, immersing the sample in an acid solution that is difficult to ionize, and removing the remaining resin, Removing the acid attached to the sample. 2. The method according to claim 1, wherein the solvent capable of softening the resin is tetrahydrofuran. 3. The method according to claim 1, wherein the corrosion preventing film is a film obtained by depositing gold. 4. The method according to claim 1, wherein the acid solution that does not easily ionize the sample is a concentrated acid.