JP2016033471A - Manufacturing method of observation sample - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an observation sample easily detaching a thin sample from a probe, and having less risk of failure.SOLUTION: A manufacturing method of an observation sample 10 in which a thin sample 2 adheres onto a support film 4 includes: a probe adhesion step of making the thin sample 2 adhere to a probe 3 comprising a non-conductive material; an arrangement step in which by moving the probe 3, the thin sample 2 adhering to the probe 3 in the probe adhesion step is arranged at a predetermined position lower than 10 μm on the support film 4; and a support film adhesion step in which by spraying misty liquid L to the thin sample 2 arranged at the predetermined position in the arrangement step, the thin sample 2 is detached from the probe 3 and adheres onto the support film 4.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for producing an observation sample in which a thin piece sample is attached on a support film.

  A method for preparing an observation sample using a focused ion beam (FIB) apparatus is known (see, for example, Patent Documents 1 to 3 and Non-Patent Documents 1 and 2). A part of the bulk sample is cut into a thin piece by the focused ion beam device to obtain a thin piece sample. The flake sample is transported onto the support film while being attached to the probe by static electricity. The observation sample is produced by the thin sample carried on the support film being detached from the probe tip and adhering to the support film.

JP 2004-354371 A JP 2006-019213 A JP 2008-008850 A

Masao Hirasaka, “FIB / Ion Milling Technique Q & A for Electron Microscope Researchers”, Agne Jofusha, September 2002 Kentaro Asakura, “Q & A of electron microscope sample preparation techniques learned from failures for electron microscope researchers”, Agne Jofusha, June 2006

  In the conventional method for preparing an observation sample, it is difficult to separate the thin sample from the probe when the thin sample is adhered on the support film. For this reason, while the thin sample was brought into contact with the support film so as to be detached from the probe, the support film was damaged by the probe, and the preparation of the observation sample sometimes failed.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for producing an observation sample that is easy to detach a thin piece sample from a probe and is less likely to fail.

  An observation sample manufacturing method according to one embodiment of the present invention is an observation sample manufacturing method in which a thin sample is attached to a support film, and the probe attaching step of attaching the thin sample to a probe made of a non-conductive material. And by moving the probe, the thin film sample attached to the probe by the probe attaching process is arranged at a predetermined position lower than 10 μm on the support film, and the thin piece arranged at the predetermined position by the arranging process A supporting film attaching step of spraying a mist-like liquid onto the sample to separate the thin sample from the probe and attach it to the supporting film.

  According to the present invention, it is possible to provide a method for producing an observation sample that is easy to detach a thin piece sample from a probe and is less likely to fail.

It is a figure explaining the acquisition process and probe adhesion process in the preparation method of the observation sample concerning one form of the present invention. It is a figure explaining the arrangement | positioning process in the preparation methods of the observation sample which concerns on one form of this invention. It is a figure explaining the support film adhesion process in the manufacturing method of the observation sample concerning one form of the present invention. It is a photograph figure of an example of an observation sample. It is a figure explaining the observation method of an observation sample. It is a figure explaining the preparation methods of the conventional observation sample.

  An observation sample manufacturing method according to one embodiment of the present invention is an observation sample manufacturing method in which a thin sample is attached to a support film, and the probe attaching step of attaching the thin sample to a probe made of a non-conductive material. And by moving the probe, the thin film sample attached to the probe by the probe attaching process is arranged at a predetermined position lower than 10 μm on the support film, and the thin piece arranged at the predetermined position by the arranging process A supporting film attaching step of spraying a mist-like liquid onto the sample to separate the thin sample from the probe and attach it to the supporting film.

  As described above, in the above production method, the thin piece sample attached to the probe is placed at a predetermined position lower than 10 μm on the support film and sprayed with a mist-like liquid, so that the thin piece sample is detached from the probe and supported. Easy to adhere on the film. Therefore, it is not necessary to bring the thin sample into contact with the support film in order to detach the thin sample from the probe and attach it to the support film. As a result, the support film is damaged by the probe, and there is little possibility that the preparation of the observation sample fails.

  The observation sample manufacturing method may further include an acquisition step of acquiring a thin piece sample by cutting a part of the bulk sample into a thin piece shape with a focused ion beam apparatus. In this case, a thin sample can be obtained by cutting out an arbitrary fine portion of the bulk sample.

  In the above-described observation sample manufacturing method, the mist-like liquid may be water having a purity of 99% or more. In this case, the electrostatic force acting between the probe and the thin sample can be easily weakened.

[Details of the embodiment of the present invention]
A specific example of a method for producing an observation sample according to an embodiment of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes within the meaning and range equivalent to a claim are included.

  The observation sample preparation method according to the present embodiment is to prepare an observation sample by sequentially performing an acquisition step, a probe attachment step, an arrangement step, and a support film attachment step. The observation sample produced by this production method can be used for analysis by, for example, a transmission electron microscope (TEM), a scanning electron microscope (SEM), a scanning transmission electron microscope (STEM), an Auger spectrometer, and the like. Hereinafter, the detail of each process mentioned above is demonstrated.

  First, an acquisition process and a probe attachment process will be described with reference to FIG. FIG. 1 is a diagram illustrating an acquisition process and a probe attachment process in the observation sample manufacturing method according to the present embodiment. In the acquisition step, a part of the bulk sample 1 is cut into a thin piece by a focused ion beam (FIB) apparatus (not shown) to obtain the thin piece sample 2. The flake sample 2 is completely separated from the bulk sample 1 by FIB processing. In the present embodiment, the thin piece sample 2 is cut into a square shape having a thickness of 0.1 μm and a side of 10 μm, for example. The shape of the flake sample 2 may be rectangular when viewed from the thickness direction. The sliced sample 2 cut out is taken out from the bulk sample 1 using a microscope with a manipulator (not shown) provided with the probe 3. This method of taking out the sample is called a lift-out method.

  In the probe attaching step, the thin sample 2 is attached to the probe 3 made of a non-conductive material. The probe 3 is made of a non-conductive material, for example, glass (quartz). The probe 3 has a shape whose tip is sharpened to about several μm. The probe 3 is used by being attached to a manipulator. When the tip of the probe 3 is brought close to the thin sample 2, the thin sample 2 is attracted by the static electricity at the tip of the probe 3 and adheres to the tip of the probe 3.

  Next, an arrangement process will be described with reference to FIG. FIG. 2 is a diagram for explaining an arrangement step in the observation sample manufacturing method according to the present embodiment. In the placement step, the probe 3 is moved to place the thin sample 2 attached to the probe 3 in the probe attachment step at a predetermined position lower than 10 μm on the support film 4. That is, the thin piece sample 2 is disposed at a predetermined position such that the distance d between the thin piece sample 2 and the support film 4 is smaller than 10 μm. At this time, by adjusting the position of the probe 3, the thin sample 2 is arranged so that the main surface of the thin sample 2 is parallel to the support film 4. By setting the predetermined position at which the thin piece sample 2 is disposed to a position lower than 10 μm on the support film 4 (for example, several μm), the thin piece sample 2 can be easily attached on the support film 4 in the subsequent support film attaching step. .

  The support film 4 is, for example, an organic film, and is configured to transmit an electron beam using carbon or the like as a material. The thickness of the support film 4 is about 5 to 80 nm. The support film 4 is provided on a frame 5 (see FIG. 3) constituting an observation mesh grid. The frame 5 is made of a metal such as copper (Cu), for example.

  Next, with reference to FIG. 3, the supporting film attaching step will be described. FIG. 3 is a diagram for explaining a support film attaching step in the method for producing an observation sample according to the present embodiment. In the support film attaching step, the thin sample 2 is detached from the probe 3 and attached onto the support film 4 by spraying the mist-like liquid L onto the thin piece sample 2 placed at a predetermined position in the placement step. The liquid L is, for example, water having a purity of 99% or more (ultra pure water), alcohol, or the like. The liquid L is atomized from the tip of the dropper humidifier 6 and sprayed onto the thin piece sample 2. The electrostatic force acting between the tip of the probe 3 and the thin sample 2 is weakened by the liquid L. Further, a water droplet enters between the thin piece sample 2 and the support film 4, and an adsorption force is generated between the thin piece sample 2 and the support film 4. As a result of this attraction force surpassing the electrostatic force, the flake sample 2 is detached from the probe 3 and adheres to the support film 4. In the arrangement step, when the thin piece sample 2 is arranged at a height of 10 μm or more on the support film 4, the distance from the probe 3 to the support film 4 is long when the thin piece sample 2 is detached from the probe 3. And the thin piece sample 2 does not adhere to the target position or is greatly deviated from the target position and the thin piece sample 2 is likely to be lost. Thus, since the liquid L is used and the thin sample 2 is easily detached from the probe 3, there is little possibility of damaging the support film 4.

  FIG. 4 is a photograph of an example of an observation sample. The observation sample 10 is formed by attaching the thin piece sample 2 on the support film 4 in this way. The support film 4 is provided on the frame 5. A plurality of frames 5 are arranged at predetermined intervals. In this example, the frame 5 is a square Cu frame having a side of 40 μm, and the support film 4 is a film having a thickness of 30 nm. The shape of the frame 5 is not limited to a rectangular shape such as a square shape, and may be a circular shape or the like.

  Then, the thin piece sample 2 attached on the support film 4 in the support film attachment step is observed and analyzed by, for example, TEM as shown in FIG. When performing observation, high-resolution observation can be performed by, for example, irradiating and transmitting the thin piece sample 2 of the observation sample 10 with the electron beam B.

  Here, with reference to FIG. 6, the difference between the method for producing the observation sample according to the present embodiment and the method for producing the observation sample according to the conventional example will be described. 6A and 6B are diagrams for explaining a conventional method for producing an observation sample. FIG. 6A illustrates how a thin sample is brought into contact with a support film, and FIG. 6B illustrates a thin sample as a support film. The manner in which the support membrane is damaged as a result of being brought into contact with is described. Thus, in the conventional method for preparing an observation sample, the thin piece sample 2 is brought into contact with the support film 4 in order to separate the thin piece sample 2 from the probe 3. However, since the electrostatic force acting between the tip of the probe 3 and the thin piece sample 2 is larger than the adsorption force acting between the thin piece sample 2 and the support film 4, the thin piece sample 2 is not easily detached from the probe 3. For this reason, in order to detach the thin sample 2 from the probe 3, it was necessary to rub the thin sample 2 on the support film 4 many times. As a result, the support film 4 is broken and broken, and the thin sample 2 may be lost.

  On the other hand, in the method for producing an observation sample according to the present embodiment, the thin piece sample 2 attached to the probe 3 is disposed at a predetermined position lower than 10 μm on the support film 4, and in contrast to the mist shape The liquid L is sprayed. Thereby, the electrostatic force which worked between the front-end | tip of the probe 3 and the thin piece sample 2 can be weakened. Further, an adsorption force can be generated between the thin piece sample 2 and the support film 4 by allowing water droplets to enter between the thin piece sample 2 and the support film 4. Therefore, according to the method for producing an observation sample according to the present embodiment, the thin sample 2 is easily detached from the probe 3 and attached to the support film 4 as a result of the attraction force surpassing the electrostatic force. For this reason, it is not necessary to bring the thin sample 2 into contact with the support film 4 in order to separate the thin sample 2 from the probe 3. Therefore, the possibility that the support film 4 is damaged by the probe 3 and the production of the observation sample 10 fails will be reduced.

  Further, the above manufacturing method further includes an acquisition step of acquiring a thin piece sample 2 by cutting out a part of the bulk sample 1 into a thin piece shape with a focused ion beam apparatus. Therefore, a thin sample 2 can be obtained by cutting out an arbitrary fine portion from the bulk sample 1.

  Further, in the above production method, water having a purity of 99% or more is used as the mist-like liquid L. In this case, the electrostatic force acting between the probe 3 and the thin sample 2 can be easily weakened.

  The present invention is not limited to the above embodiment. For example, the flake sample 2 is not limited to one cut out from the bulk sample 1 by the focused ion beam apparatus, and may be obtained by other methods.

  In order to confirm the effect of this embodiment, in the arrangement step, a comparison was made between the case where the thin piece sample 2 was arranged at a height of less than 10 μm on the support film 4 and the case where the thin piece sample 2 was arranged at a height of 30 μm. When arranged at a height of less than 10 μm, the thin sample 2 is detached from the probe 3 by spraying ultrapure water as the liquid L from the tip of the dropper humidifier 6 in the supporting film attaching step, and on the supporting film 4. It was possible to adhere. On the other hand, when it is arranged at a height of 30 μm, when the thin piece sample 2 is detached from the probe 3 in the support film attaching step, the distance to the support film 4 is long and the thin piece sample 2 does not fall linearly from the probe 3. The thin piece sample 2 could not be attached to the target position on the support film 4 or was greatly deviated from the target position and lost. Thus, according to the method for producing the observation sample 10 according to the present embodiment, it was confirmed that the thin sample 2 was easily detached from the probe and there was little risk of failure.

DESCRIPTION OF SYMBOLS 1 ... Bulk sample, 2 ... Thin piece sample, 3 ... Probe, 4 ... Support film, 10 ... Observation sample, B ... Electron beam, L ... Liquid.

Claims (3)

A method for producing an observation sample in which a thin sample is adhered on a support film,
A probe attaching step of attaching the thin sample to a probe made of a non-conductive material;
An arrangement step of disposing the thin piece sample attached to the probe by the probe attachment step at a predetermined position lower than 10 μm on the support film by moving the probe;
A support film attaching step of spraying a mist-like liquid onto the thin piece sample placed at the predetermined position in the placement step so that the thin piece sample is detached from the probe and attached onto the support film. Sample preparation method.   The method for producing an observation sample according to claim 1, further comprising an obtaining step of obtaining a piece of the bulk sample by cutting a part of the bulk sample into a thin piece with a focused ion beam apparatus. The method for producing an observation sample according to claim 1 or 2, wherein the mist-like liquid is water having a purity of 99% or more.