JPH09126968A - Method for preparing sample for transmission-type electronic microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preparing a flat and thin sample for a transmissiontype electronic microscope over a wide range. SOLUTION: A recess 11 is formed at a part for observing a test piece 10 (Process 101), a groove 12 which is approximately 10μm deep is formed at a specific part on the bottom surface of the formed recessed 12 using focusing beams, and water 13 is poured into the recess 11 (Process 102). Then, the lower surface of the test piece 10 is dipped into an etching liquid, the water 13 flowing out of the bottom surface of the groove 12 is mixed with an etching liquid at the same time when the inside surrounded by the groove 12 is separated when etching due to an etching liquid reaches a surface a-a' of the test piece 10 for diluting the etching liquid, thus stopping the progress of etching and obtaining a thinned test piece 14 (Process 103).

Description

Detailed Description of the Invention

[0001]

The present invention relates to a method for preparing a sample for a transmission electron microscope, and more particularly to a method for preparing a flat and thin sample for a transmission electron microscope over a wide range.

[0002]

2. Description of the Related Art In a transmission electron microscope, electrons accelerated under a high voltage are transmitted through a crystal material, and a diffraction wave caused by scattering of electrons in the crystal material is observed as an image. In order to be able to observe the structure, surface morphology, defects and the like of semiconductors and metals with a high resolution using a transmission electron microscope, the crystalline material as a sample must be extremely thin.

FIG. 3 is a perspective view for explaining a conventional method for manufacturing a sample for a transmission electron microscope.

As shown in FIG. 3, in a conventional method for preparing a sample for a transmission electron microscope, first, a sample cut into a size of about 3 μmφ (diameter) × 1 μm (thickness) using a diamond cutter or the like. The piece 30 is mechanically polished from the direction of the mechanically polished surface 31 to be thinned to a thickness of about 100 μm (step 301).

Subsequently, only the portion near the observation point is reduced to a thickness of about 10 to 20 μm by bowl polishing (step 302), and the observation point 32 is further reduced to several thousand angstroms using an ion milling device. The sample is made thinner for a transmission electron microscope (step 303).

[0006]

However, in a transmission electron microscope sample manufactured by the above-mentioned conventional method, the entire sample is flattened and has a thickness of 10 to 20 by mechanical polishing.
Since it is difficult to reduce the thickness of the sample to a thickness of μm, a portion other than the vicinity of the observation point of the sample becomes thick, and there is a problem that the observable range is limited.

Accordingly, the present invention has been made in view of the above problems, and has as its object to provide a method for manufacturing a flat and thin sample for a transmission electron microscope over a wide range.

[0008]

In order to achieve the above object, the present invention provides a method of forming a groove using a focused beam focused around an observation point of a sample, and forming a groove at the position where the groove is formed on a bottom surface. After forming a dent including in the dent and injecting a liquid for suppressing etching into the dent, wet etching is performed on the end surface opposite to the end surface of the sample in which the groove is formed to obtain a flat and thin sample over a wide range. A method for producing a transmission electron microscope sample, which is a feature of the present invention, is provided.

The present invention also provides a method of forming a groove using a focused beam focused around an observation position of a sample, forming a depression including the position where the groove is formed on the bottom surface, and etching the depression. After injecting a liquid that suppresses the etching, the recess is sealed by a substrate that is not attacked by etching, and the sample is wet-etched to obtain a flat and thin sample over a wide range. A method of making is provided.

Further, according to the present invention, a groove having a predetermined depth is formed around an observation point of a sample, and an end surface opposite to the end surface of the sample in which the groove is formed is etched using an etching solution. A method for producing a sample for a transmission electron microscope, characterized in that, when etching is performed up to the position of the bottom surface of the groove, a liquid that suppresses etching through the groove is mixed with the etching liquid. provide.

According to the method for manufacturing a sample for a transmission electron microscope of the present invention, for example, a recess is formed in a sample cut with a diamond cutter or the like, and a focused beam focused on the bottom surface of the formed recess is used. A groove having a depth of about 10 to 20 μm is formed so as to surround the observation point. A liquid that suppresses etching, for example, water is injected into the depression.

Thereafter, the end surface opposite to the end surface of the sample in which the depression is formed is immersed in an etching solution, and when the etching reaches the bottom surface of the groove, the inner portion surrounded by the groove is separated from the sample at the same time. The liquid injected into the recess flows out through the bottom of the groove. The effluent liquid is mixed with the etching solution to stop the progress of the etching, so that it is finally flat and has a thickness of about 10 to 20 over a wide range.
A μm thinned sample piece can be obtained.

The thinned sample obtained as described above can be further thinned to a thickness of several thousand angstroms using an ion milling device or the like, if necessary.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0015]

Embodiment 1 First, a method for manufacturing a sample for a transmission electron microscope according to a first embodiment of the present invention will be described.

FIG. 1 is a perspective view and a sectional view for explaining a method for manufacturing a sample for a transmission electron microscope according to the first embodiment of the present invention.

As shown in FIG. 1, first, silicon (S
i) In a device (sample piece 10) on a substrate, the periphery of a portion to be observed is masked with wax, and this is wet-etched to form a depression 11 (step 101). The depression 11 can also be formed by using a focused ion beam.

Next, using a focused ion beam, a groove 12 having a depth of about 10 μm is formed at a predetermined position on the bottom surface of the depression 11, and water 13 is injected into the depression 11 (step 10).
2). The groove 12 is formed so as to have a rectangular shape or the like when viewed from above, for example, according to the size of the finally obtained thinned sample piece 14. As shown in FIG. 1, the portion to be formed may be a portion along the outer periphery of the bottom surface of the recess 11 or may be any portion within the bottom surface of the recess 11.

Thereafter, the lower surface of the sample 10 is immersed in a mixed solution of hydrofluoric acid and nitric acid (hereinafter referred to as "etching solution"). The mixing ratio between hydrofluoric acid and nitric acid is 1:80.

When the etching with the etchant reaches the a-a 'plane of the sample piece 10, the water 13 flowing out from the bottom face of the groove 12 is simultaneously separated from the inside of the groove 12 from the sample piece 10. Is mixed with the etching solution to dilute the etching solution, so that the progress of the etching is stopped and the sliced sample piece 14 is obtained (step 103).

By skimming the thinned sample piece 14 out of the etching solution with a mesh or the like, a flat thinned sample piece having a thickness of about 10 μm can be finally obtained over a wide range.

When the obtained thinned sample piece 14 having a thickness of about 10 μm is further thinned using an ion milling apparatus, a transmission electron microscope image is observed over a wider area than the sample manufactured by the conventional method. I was able to.

[0023]

Embodiment 2 Next, a method for manufacturing a sample for a transmission electron microscope according to a second embodiment of the present invention will be described.

FIG. 2 is a perspective view and a sectional view for explaining a method for manufacturing a sample for a transmission electron microscope according to a second embodiment of the present invention.

As shown in FIG. 2, first, silicon (S
i) In a device (sample piece 20) on a substrate, a groove 21 having a depth of about 10 μm is formed near a point to be observed using a focused ion beam (step 201). Groove 21
Is formed, for example, in a rectangular shape when viewed from above, in accordance with the size of the sliced sample piece 26 finally obtained.

Next, a recess 22 is formed by surrounding the area where the groove 21 is formed with a ceramic plate 23 (step 202), and the ceramic substrate 24 is fixed to the upper surface of the ceramic plate 23 with wax. Sample piece 2
Water 25 is filled in the gap between the substrate 0 and the ceramic substrate 24 (step 203).

Thereafter, the entire sample piece 20 is immersed in a mixed solution of hydrofluoric acid and nitric acid (hereinafter referred to as "etching solution"). The mixing ratio between hydrofluoric acid and nitric acid is 1:80.
And

When the etching with the etchant reaches the bb 'plane of the sample piece 20, the inner portion of the groove 21 separates from the sample piece 20 and the water 25 flowing out of the bottom face of the groove 21 at the same time. Is mixed with the etching solution to dilute the etching solution, so that the progress of the etching is stopped and the sliced sample piece 26 is obtained (step 204).

By skimming the thinned sample piece 26 out of the etching solution with a mesh or the like, finally, a flat thinned sample piece having a thickness of about 10 μm can be obtained over a wide range.

When the obtained thinned sample piece 26 having a thickness of about 10 μm was further thinned using an ion milling apparatus, a transmission electron microscope image was observed over a wider area than the sample manufactured by the conventional method. I was able to.

Although several embodiments of the present invention have been described above, the present invention is not limited to these embodiments, but includes various embodiments according to the principles of the present invention.

For example, a laser beam other than an ion beam can be used as a focused beam for forming the grooves 12 and 21 around the observation point.

As the liquid to be injected into the depressions 11 and 22, an alkaline liquid that neutralizes an acidic etching liquid can be used in addition to water.

[0034]

As described above, according to the method for preparing a sample for a transmission electron microscope of the present invention, a flat and thin sample can be obtained over a wide range before performing ion milling. A sample for a transmission electron microscope having a wider observation range than the manufactured sample can be manufactured.

Further, according to the method for manufacturing a sample for a transmission electron microscope of the present invention, a minute portion can be easily specified by using a focused beam, and thus a minute portion which cannot be specified by a conventional method. A sample for a transmission electron microscope in which a part can be observed can be manufactured.

[Brief description of the drawings]

FIGS. 1A and 1B are a perspective view and a cross-sectional view illustrating a method for manufacturing a sample for a transmission electron microscope according to a first embodiment of the present invention.

2A and 2B are a perspective view and a cross-sectional view for explaining a method for manufacturing a sample for a transmission electron microscope according to a second embodiment of the present invention.

FIG. 3 is a perspective view for explaining a conventional method for manufacturing a sample for a transmission electron microscope.

[Explanation of symbols]

 10, 20, 30 Sample piece 11, 22 Recess 12, 21, Groove 13, 25 Water 14, 26 Thinned sample piece 23 Ceramic plate 24 Ceramic substrate 31 Mechanically polished surface 32 Observation point

Claims (5)

[Claims] 1. A liquid which forms a groove using a focused beam focused around an observation point of a sample, forms a recess including a portion where the groove is formed on a bottom surface, and suppresses etching in the recess. And then performing wet etching on an end surface of the sample on which the groove is formed, opposite to the end surface of the sample, to obtain a flat and thin sample over a wide range, the method for manufacturing a sample for a transmission electron microscope. 2. The method for producing a sample for a transmission electron microscope according to claim 1, wherein water is used as the liquid for suppressing the etching. 3. A liquid which forms a groove by using a focused beam focused around an observation position of a sample, forms a recess including a portion on which the groove is formed on a bottom surface, and suppresses etching in the recess. A method for preparing a sample for a transmission electron microscope, wherein the sample is wet-etched after sealing the dent with a substrate that is not affected by etching after the injection of the sample, thereby obtaining a flat and thin sample over a wide range. 4. The method for producing a sample for a transmission electron microscope according to claim 3, wherein water is used as the liquid for suppressing the etching. 5. A groove having a predetermined depth is formed around an observation point of a sample, and an end surface opposite to the end surface of the sample in which the groove is formed is etched using an etching solution, and a bottom surface of the groove is formed. A method of manufacturing a sample for a transmission electron microscope, wherein a liquid that suppresses etching through the groove is mixed with the etching liquid when the etching is performed up to the position.