JPH06213785A - Preparation of sample observed by electronic microscope - Google Patents

Abstract

PURPOSE:To prepare a sample allowing observation of a specified region from a plurality of directions through an electronic microscope while ensuring very high positioning accuracy. CONSTITUTION:The method for preparing a sample allowing observation of a specified region 11 thereof from both cross-sectional direction and planar direction through an electronic microscope comprises a step (A) for cutting a material to be observed at a width mountable on an electronic microscope by means of a high speed rotary cutter having outer peripheral blade while observing the material by means of a high magnification optical microscope equipped to the cutter, a step (B) for putting a mark 12 at a specified point, steps (D-E) for forming thus cut material into C-shaped or L-shaped groove, and steps (F-G) for making thinner the bottom face of the C-shaped material and the surface of the L-shaped material by etching using converged charged particle beam.

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 sample for electron microscope observation (hereinafter, simply referred to as "sample"), and particularly a very small specific region of the same sample from both cross-section and plane directions. The present invention relates to a method of preparing a sample that can be observed.

[0002]

2. Description of the Related Art As a conventional method for preparing a sample for electron microscope observation, the present applicant has applied for Japanese Patent Application No. 04/019447 or No. 072764/2004.

[0003]

However, the above-mentioned conventional method for preparing a sample for electron microscope observation cannot observe a specific region of the sample from a plurality of different directions. Therefore, when observing the specific region from the cross-sectional direction and the plane direction, for example, two separate samples, a sample to be observed from the cross-sectional direction of the specific region and a sample to be observed from the plane direction, must be prepared. I have to.

The present invention has been devised in view of the above circumstances, and provides a method of preparing a sample which has a very high alignment accuracy and which can observe a specific region from a plurality of different directions by an electron microscope. The purpose is to do.

[0005]

A method for preparing an electron microscope observing sample according to the present invention is a method for preparing an electron microscope observing sample capable of observing a specific region of the same observing sample from both directions of a cross section and a plane. That is, for materials that require electron microscope observation, the material has a width that can be attached to an electron microscope while observing with the optical microscope using a high-speed rotating outer peripheral blade processing device equipped with an optical microscope with high magnification. And a step of marking at a specific place, and the material cut into a width that can be attached to the electron microscope has a concave shape or L shape.
A step of processing into a groove shape such as a letter shape, and the original surface of the bottom surface of the concave shape or the L-shaped material by etching with a focused charged particle beam And a step of further thinning.

[0006]

EXAMPLE FIG. 1 is an explanatory view showing a method for preparing an electron microscope observing sample according to an embodiment of the present invention, and FIG. 2 is an electron microscope observing a sample prepared by this electron microscope observing sample preparing method. 3 is a perspective view of a sample prepared by the method for preparing a sample for electron microscope observation, FIG.
FIG. 6 is a perspective view of a sample having another shape created by the method for creating a sample for electron microscope observation.

As shown in FIG. 1 (A), a focused charged particle beam device, a laser beam processing device or a micro knife is centered on a specific region 11 (indicated by "+" in the drawing) which requires observation. About 4 to 10 markings 12 (indicated by "." In the drawing) are formed by using the same (4 markings 12 are formed in the drawing). This stamp 1
2 is cutting and cutting with a high-speed rotating outer peripheral blade processing device,
It is a processing target for thinning processing with a convergent charged particle beam device.

A blade 13 of a high-speed rotating outer peripheral blade processing apparatus is run along a processing line 14 formed on a silicon wafer 200, and a sample 1 including a specific region 11 is transferred to a silicon wafer 20.
Cut out from 0. As shown in FIG. 1B, the sample 1 has a width dimension a and a height dimension b. In the embodiment, a
Was about 70 μm. Further, b is a silicon wafer 20.
It becomes equal to the thickness dimension of 0.

The sample 1 is turned upside down and fixed to a stage (not shown) by the supports 15 from both sides (see FIG. 1).
(See (C)). The support 15 fixes the sample 1 so that it does not move during cutting by the high-speed rotating outer peripheral blade processing device, and for example, a silicon piece is used. The support 15 can be cut out from the silicon wafer 200 at the same time when the sample 1 is cut out. By doing so, the height dimension b becomes equal to that of the sample 1 and the sample 1 is of the same quality, so the cutting work There is an advantage that can be performed stably. Also, this support 1
For fixing with 5, when using a heat-soluble wax,
It is easy to remove after cutting work.

The sample 1 fixed by the support 15 is cut from the back side, that is, the surface side facing the surface including the specific region 11 by a high-speed rotating outer peripheral blade processing device (FIG. 1 (D)).
reference). This cutting is performed on the sample 1 as shown in FIG.
Let c be the remaining thickness dimension, d be the cutting depth dimension, and e be the cutting width dimension. The thickness of the blade 13 of the high-speed rotating outer peripheral blade processing apparatus is t. Generally, the thickness t of the blade 13 is several tens of μm.
Therefore, every time one cutting is completed, the sample 13 is cut over the cutting width dimension e by sliding the blade 13 in the X-axis direction by the amount within the thickness t. In addition,
If the thickness t of the blade 13 is selected to be thicker than the width dimension a of the sample 1, it is possible to perform processing with the cutting depth d by one cutting without sliding. In the embodiment, the blade 13
At 30000 rpm and a feed rate of 1 mm / min. The remaining thickness c of the sample 1 needs to be determined in consideration of the strength that can be attached to the electron microscope and is easy to handle, and in the example, it was set to 70 μm.

Further, the sample 1 is formed in a concave shape (see FIG. 1E). This step is performed by the blade 13 'of the high-speed rotating peripheral blade processing device having the thickness t'. Final processing thickness f is 20 μm, width dimension g of concave sample side wall is 20 μm
I am trying. Therefore, the cutting depth h is 50 μm. It is needless to say that the final processed thickness f and the width dimension g are selected so as not to be damaged by the subsequent handling of tweezers or the like. Here, since the sample 1 is silicon, each of them is set to 20 μm. The blade 13 'has a thickness t'
With a diameter of about 30 μm.

The high-speed rotating outer peripheral blade processing apparatus used when forming the sample 1 in a concave shape requires high alignment accuracy, but Japanese Patent Application No. 03-1194 filed by the applicant of the present application.
If the one described in No. 1 is used, high alignment accuracy can be satisfied. In this case, set the blade 13 'to 30,000r
Rotate at pm and feed speed of blade 13 'is 0.1 mm / min
Is desirable.

The sample 1 formed in the concave shape is removed from the stage, but since the two supports 15 are fixed by the heat-soluble wax, the stage is heated. The wax attached to the sample 1 is washed with a solvent.

Next, the sample 1 is thinned by the converged charged particle beam processing apparatus. First, as shown in FIG. 1F, a converged charged particle beam 16 is irradiated from a direction perpendicular to the specific region 11 to form a bridge-shaped bridge portion 111 including the specific region 11. The bridge portion 111 irradiates the converged charged particle beam 16 on the longitudinal edge of the surface including the specific region 11, and leaves the areas of the unprocessed width dimension i including the specific region 11 in the processed regions 17 and 17 '. (Fig. 1 (F)
(Shaded portion in FIG. 3) is removed by focused charged particle beam etching. In this embodiment, the unprocessed width dimension i is 1 to 0.1 μm.

Next, as shown in FIG. 1G, the focused region 11 of the sample 1 is irradiated with a convergent charged particle beam 16 'from a horizontal direction. That is, the converged charged particle beam 16 'is irradiated from the side surface side of the bridge portion 111 to the back surface side, and the back surface side 18 of the bridge portion 111 is removed by convergent charged particle beam etching. At this time, the unprocessed dimension j is 1 to
0.1 μm. Needless to say, the unprocessed dimensions i and j should be appropriately selected depending on the purpose of observation with an electron microscope.

When the sample 1 is silicon and high-resolution observation is required, it is necessary to thin the unprocessed dimensions i and j to about 0.1 μm. In that case, if both are thinned to 0.1 μm, the strength becomes weak. In addition, the bridge portion 111 may not have a quadrangular prism shape but may have an extremely thin cylindrical shape, which makes high-resolution observation difficult. Therefore, in practice, when one of the unprocessed dimensions i and j was thinned to 0.1 μm, the other was set to about 1 μm to secure the strength and enable high resolution observation.

The sample 1 thus obtained is observed as shown in FIG. That is, when observing the cross-sectional direction of the sample 1, the sample 1 is laid sideways, that is, the surface including the specific region 11 is oriented horizontally, and the metal plate 20 (generally a mesh or a grid) for holding an electron microscope observation sample is used. Called)). When the sample 1 is observed in the planar direction, the sample 1 is placed on the metal plate 20 with the surface including the specific region 11 facing upward. In addition, 19 in the drawing has shown the electron beam.

In the above-mentioned embodiment, the sample 1 formed by the method for preparing a sample for electron microscope observation has the shape as shown in FIG. 3, but the present invention is not limited to this. 4A to 4C may be used. The sample 1 having such a shape can be obtained by performing cutting from the front surface side of the sample 1 by a cutting depth h in the step shown in FIG. 1A and following the step shown in FIG. 1D. You can

[0019]

EFFECT OF THE INVENTION The method of preparing a sample for electron microscope observation according to the present invention is applicable to materials requiring electron microscope observation.
A step of cutting the material into a width that can be attached to an electron microscope while observing with the optical microscope using a high-speed rotating outer peripheral blade processing device equipped with a high-magnification optical microscope, and a step of giving a stamp to a specific place, The step of processing the material cut into a width that can be mounted on the electron microscope into a groove shape such as a concave shape or an L shape, and the bottom surface of the concave shape or L by etching with a focused charged particle beam. And further thinning the original surface of the V-shaped material partially into the surface of the material and the width of the material.

Therefore, according to the sample formed by this method for preparing the sample for electron microscope observation, the specific region can be observed from both the cross section and the plane. Therefore, a dislocation line, which is a kind of crystal defect generated in silicon, can be observed from both the cross section and the plane, and thus the three-dimensional crystal defect formation state can be confirmed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a method for preparing a sample for electron microscope observation according to an example of the present invention.

FIG. 2 is an explanatory diagram showing a state in which a sample prepared by the method for preparing an electron microscope observation sample is observed with an electron microscope.

FIG. 3 is a perspective view of a sample prepared by the method for preparing a sample for electron microscope observation.

FIG. 4 is a perspective view of a sample having another shape created by this method for creating a sample for electron microscope observation.

[Explanation of symbols]

 1 sample 11 specific area 12 stamp

Claims (2)

[Claims] 1. A method for producing an electron microscope observing sample capable of observing a specific region of the same observing sample from both directions of a cross section and a plane, wherein high-magnification optics is applied to a material requiring electron microscope observation. A step of cutting the material into a width that can be attached to an electron microscope while observing with the optical microscope using a high-speed rotating outer peripheral blade processing device equipped with a microscope, a step of marking at a specific place, and the electron microscope A step of processing the material cut out to a mountable width into a groove shape such as a concave shape or an L shape, and the bottom surface of the concave shape or an L shape material by etching with a focused charged particle beam And a step of further partially thinning the original surface of the material into the surface of the material and the width of the material. 2. The method for preparing a sample for electron microscope observation according to claim 1, wherein the marking is performed by a micro knife, a laser beam processing device or a converged charged particle beam device.