JP2004164966A - Focused ion beam device for transmission electron microscope sample processing equipped with writing function by coding relevant information - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a focused ion beam device for TEM sample processing adding a special process giving necessary information to a TEM sample itself to make management of the TEM sample that is a bothersome problem because of its minute size easily and simply performed. <P>SOLUTION: The focused ion beam device comprises a means for converting, when information for specifying the sample and/or information incidental to the sample are inputted, the information to a coded mark, and a means for impressing a signal, which is generated for controlling the irradiation position of a focused ion beam in order to process the mark on the surface of the sample, to a deflection means. Arrangement information on the sample is written to a TEM sample body in a form of a mark. Mark formation is implemented by an etching process using the focused ion beam, deposition by raw material gas and the irradiating of the focused ion beam, and deposition by raw material gas and the irradiating of an electronic beam. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sample manufacturing focused ion beam apparatus for writing a mark encoding related information such as self-identification in the process of preparing a sample for a transmission electron microscope.
[0002]
[Prior art]
2. Description of the Related Art It is well known that a cross-sectional sample for observation with a transmission electron microscope (hereinafter abbreviated as TEM) is formed by slicing using a focused ion beam apparatus. There are known a processing method and a method of taking out a thinned sample by performing etching processing on a wafer. The present invention relates to a TEM sample prepared by the latter method. In this TEM sample manufacturing method, as shown in FIG. 4A, a processing portion is irradiated with an ion beam while first spraying a raw material gas with a gas gun. Then, a focused ion beam is irradiated from above the surface of the sample, and the back side of the observation section is dug by etching, as shown in FIG. As shown in ()), the front side of the observation section is dug by etching. A square front hole and a rear hole are made on both sides of the observation section thin section using a focused ion beam apparatus. The size of the front hole is such that the observation section can be observed with a scanning ion microscope by tilting the sample stage, and the rear hole has the same width as the front hole and a depth of about 2/3. . Since the observation surface has been damaged by the digging process, the surface is polished by performing the finishing process with the beam current suppressed. As shown in FIG. 5D, the periphery of the sample, which has been sliced as an observation cross section by tilting the sample surface, is irradiated with a focused ion beam as shown by an arrow to perform a cutting process (bottom cut), and FIG. As shown in (1), the manipulator (glass probe) is operated to separate this section sample from the sample body, move it onto a collodion membrane-attached mesh (150 mesh) or the like, and mount it. The section sample cut out on the mesh surface adheres, and the preparation of the sample for TEM observation is completed. The completed sample has a section of about 10 μm square fixed on a mesh base having a diameter of about 3 mm, and its handling and management are troublesome because the sample size is extremely small.
[0003]
Under such circumstances, there is a demand among users for the development of rational means for managing the handling of extremely small TEM samples. 2. Description of the Related Art Conventionally, a convenient method for accessing a fine observation point in a microscope sample has been proposed in Japanese Patent Application Laid-Open No. 4-282545 (Patent Document 1). This method uses a focused ion beam apparatus (hereinafter abbreviated as FIB apparatus), and when a scanning electron microscope (hereinafter abbreviated as SEM) or a TEM sample is pre-processed, a defect or the like is present on the same sample surface. For the purpose of facilitating access even if there are a plurality of observation sites of interest, a character such as a character symbol characterizing the observation unit of interest is processed by the FIB near the place to be processed by the FIB as shown in FIG. Things. When handling the TEM sample, it is not a TEM sample that has been sliced and then cut out, fixed on a mesh and finished, but when accessing the observation cross section on a large sample such as a wafer for processing in the pre-processing stage This is a technical idea based on the problem of making it easy to specify the position, and does not solve the difficulties in handling and managing the TEM sample itself based on the fact that the sample is now very small.
[0004]
[Patent Document 1]
JP-A-4-282545, page 3, column 3, column 4, FIG.
[0005]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a TEM sample that has special processing for giving necessary information to the TEM sample itself so that handling and management of the TEM sample, which is a troublesome problem due to its small size, can be performed easily and easily. An object of the present invention is to provide a focused ion beam apparatus for processing a sample.
[0006]
[Means for Solving the Problems]
The focused ion beam apparatus according to the present invention is configured such that, when information for specifying a sample and / or information associated with the sample is input, a means for converting the information into a coded mark, and a focused ion beam for processing the mark on the sample surface. Means for generating a signal for controlling the irradiation position of the beam and applying the signal to the deflecting means, so that the sample arrangement information is written in a mark form on the TEM sample main body.
The mark is formed by etching using a focused ion beam, deposition by irradiation of a source gas and a focused ion beam, and deposition by irradiation of a source gas and an electron beam.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention has been made to write sample arrangement information in a mark form on the TEM sample itself so that handling and management of the TEM sample, which is a troublesome problem due to its small size, can be performed easily and easily. It was done. A means for inputting information specifying the sample or various information accompanying the sample to a focused ion beam apparatus for producing a TEM sample; a means for converting the information into a coded mark; Focused ion beam (hereinafter abbreviated as FIB) for processing into a surface.
) For generating a signal for controlling the irradiation position and applying the signal to the deflecting means. In the process of thinning the TEM sample body, information for specifying the TEM sample or related information accompanying the sample is provided. Writing was added. The writing position is, as shown in FIG. 1, a peripheral position of the sample which is not to be observed as a sample, and it is convenient to arrange the sample if it is determined at a predetermined position.
[0008]
As a method of writing directly on the sample, a mark can be formed by etching using FIB, deposition by irradiation of a source gas and FIB, or deposition by irradiation of a source gas and electron beam. The mark can be represented in an appropriate form such as a number, a bar code, or a special symbol. As shown in FIG. 2, a mark is provided in a ROM storing coding rules, and information input by input means such as a keyboard (input operation unit 12) is specified according to the coding rules stored in the ROM. Convert to mark. The computer 10 provided in the FIB apparatus for producing a TEM sample recognizes the mark. At the same time, in order to write and process the mark on the sample surface, an XY deflection control signal for deflecting and scanning the charged particle beam is generated and transmitted to the deflector 4 of the apparatus. This charged particle beam is not limited to FIB. In the case where an electron lens barrel for observation is provided, processing using the electron beam may be performed. Since there is a risk of damaging the surface of the TEM sample, there is a situation in which the ion beam should not be irradiated as much as possible. Performing the mark formation by deposition using an electron beam is preferable in that respect.
[0009]
Embodiment 1
One embodiment of the present invention will be described with reference to FIGS. The FIB apparatus for processing a TEM sample according to the present embodiment is an ion optical system 3 (including an ion source 1, a condenser lens, a beam blanker, an aligner, an aperture, and an objective lens) which is a basic configuration of the general FIB apparatus shown in FIG. Condenser lens, beam blanker, aligner, aperture, objective lens), deflector 4 for performing ion beam deflection scanning, secondary charged particle detector 5, gas gun 6, sample stage 7 having stage drive mechanism 7a, charge new It comprises a riser 8, an input operation unit 12, a computer 10 and a display 11. The computer 10 outputs various control signals for controlling acceleration voltage, ion optical system, deflection scanning, gas supply, and sample stage drive.
As a characteristic configuration, the apparatus according to the present embodiment includes, as shown in FIG. 2, a ROM in which a coding rule for converting information input by an input operation unit 12 including a keyboard or the like into a mark is stored in a computer 10. Further, in addition to a function of converting information inputted according to the coding rule of the ROM into a mark, a function of recognizing the mark, and an XY for deflecting and scanning the charged particle beam for writing and processing the mark on the sample surface. It has a function of generating a deflection control signal. Then, an XY deflection control signal generated in the computer 10 is transmitted to the deflector 4, and the deflection of the ion beam 2 is controlled to process a mark on a predetermined portion of the sample 9. This processing mode can perform any of sputter etching, gas assisted etching, and deposition. Further, this embodiment is provided with a manipulator having a glass probe having a function of picking up a cross-section sample on which mark processing has been performed and transferring the sample onto a mesh, and a dedicated tray for setting the mesh.
[0010]
4 shows a TEM sample manufacturing process using this apparatus. The sample is placed on the sample stage 7, and a drift mark serving as a reference point is formed at a predetermined position near a region to be cut out as a TEM sample on the sample surface by sputter etching using FIB. Note that this may be a mark display by deposition. A protective cover deposition is performed on the surface of the sample area specified using the drift mark as a reference point, as in FIG. Subsequently, as in FIGS. 4B and 4C, a front hole and a rear hole are formed on both sides of the observation section by etching. The beam current at this time is set to a high current, and so-called rough processing is performed.
When curtain-shaped folds (curtain effect) occur on the surface due to this rough processing, the sample is tilted along the surface, and the FIB is irradiated from a different angle with a slightly reduced beam current to reduce the curtain effect. The so-called medium processing to eliminate the problem is performed. When the stage is moved at this time, this processing is performed while detecting the preceding drift mark and confirming the position for alignment. If the curtain effect is not significant, the intermediate processing may be omitted. Since the sample surface at this stage has been etched by medium processing or rough processing, the surface is in a damaged state. Therefore, a finishing process for polishing the surface is performed. The etching process at that time is performed by lowering the beam current. At the time of this processing, since the remaining width is very narrow, 50 nm to 100 nm, it is necessary to determine the processing position strictly. In addition, since the sample is in a state of being deformed by heat due to thinning, there is also a problem that the position is easily shifted. Therefore, the work must be carefully performed while repeating the positioning with reference to the drift mark. The above operation is not much different from the conventional TEM sample preparation process using the FIB apparatus.
[0011]
The features of the present invention correspond to the subsequent work. At the stage where the finishing process has been performed, the sample stage is tilted in a direction in which the sample cross section is laid down, and the FIB irradiation position is adjusted to a portion that is a non-observation area of the sample cross section, in this example, the lower left portion of the sample cross section. Information for specifying the TEM sample being manufactured or information accompanying the sample is input from the input operation unit 12. This input information is code-converted by the mark conversion unit 10a based on code conversion information stored in the ROM 10b. This code mark is recognized on a computer. Then, an XY deflection control signal generation unit 10c calculates an XY deflection control signal for etching the code mark on the sample surface by FIB. By outputting the XY deflection control signal generated by the calculation to the deflector 4 and irradiating it with an ion beam, a coded mark is engraved on the lower left portion of the sample cross section as shown in FIG.
At this stage, a so-called bottom cut in which a cut is made in the periphery of the section of the sample that has been sliced in the same manner as in FIG. As shown in FIG. 1, the sliced section where the bottom cut has been performed is connected to the sample body in a state of being supported at one point. In the same manner as shown in FIG. 5, the manipulator is operated to separate the bottom-cut cross-section sample from the sample main body and apply the collodion film in the special tray to the sample cross section on which the coded mark is engraved. It is moved and placed on a mesh (150 mesh) or the like. The section sample cut out on the mesh surface adheres, and the preparation of the sample for TEM observation is completed.
The above-mentioned TEM sample manufacturing process can be performed not only by manual operation but also can be automated by programming a series of processes by setting and inputting various conditions in advance.
[0012]
The TEM sample of the present invention thus manufactured is placed on a TEM sample stage, and is used for observation as a transmission image. At this time, not only can the observed cross section be displayed on a display as a microscope image as in the conventional case, but also the TEM sample prepared according to the present invention has information attached to the sample at the periphery (lower left region in the above example) of the sample. Is encoded and processed and displayed as a mark, so that this mark can also be captured as a microscope image and displayed as an image. The operator can read the base (original) information from the code information and recognize the accompanying information of the sample before observing the cross section. If the TEM has a function of reading the code information and converting it back to the original (original) data and displaying it, the accompanying information of the sample should be displayed on the display in the form of a table or the like. The cross-sectional observation image and the accompanying information can be switched and displayed, or can be divided and displayed in the form of a window. It is extremely convenient for inspection work.
[0013]
【The invention's effect】
The FIB apparatus for processing a TEM sample according to the present invention includes means for inputting information for specifying a sample and / or information associated with the sample, means for converting the input information into a coded mark, and Means for generating a signal for controlling the irradiation position of the charged particle beam for writing on the surface and applying the signal to the deflection means, so that information related to the TEM sample can be written to the TEM sample itself. Even though the TEM sample created by the FIB apparatus of the present invention is a sample having an extremely small size, it is possible to easily specify and manage the TEM sample without fail.
In actual sample observation, inspection can be performed while referring to relevant information of the sample, which is extremely convenient in practice.
Further, the processing and formation of the mark on the sample surface, which is a feature of the present invention, is performed by sputter etching using FIB or by deposition formed by injecting a raw material gas. It can be easily implemented as an extension of.
[Brief description of the drawings]
FIG. 1 is a diagram showing a TEM sample processed by an FIB apparatus of the present invention before being cut out as a section.
FIG. 2 is a block diagram showing a main configuration of a TEM sample processing FIB apparatus of the present invention.
FIG. 3 is a diagram showing a basic configuration of a FIB apparatus for processing a TEM sample.
FIG. 4 is a diagram illustrating a TEM sample processing process.
FIG. 5 is a diagram illustrating a process of fixing a sliced TEM sample section on a mesh.
FIG. 6 is a diagram showing a conventional technique that facilitates identification of a SEM sample and a TEM sample by FIB processing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ion source 10 Computer 2 Ion beam 10a Mark conversion part 3 Ion optical system 10b ROM
Reference Signs List 4 Deflector 10c XY deflection control signal generator 5 secondary charged particle detector 6 gas gun 7 sample stage 7a stage drive mechanism 8 charge nutrizer 9 sample

Claims (4)

Means for inputting information specifying the sample and / or information associated with the sample, means for converting the input information into a coded mark, and irradiation with a charged particle beam for writing and processing the mark on the sample surface Means for producing a signal for controlling the position and applying the signal to a deflecting means. 2. The focused ion beam apparatus for processing a TEM sample according to claim 1, wherein the mark on the sample surface is processed by sputter etching using a focused ion beam. 2. The focused ion beam apparatus for processing a TEM sample according to claim 1, wherein the mark on the sample surface is formed by spraying a source gas and irradiating a focused ion beam. 2. The focused ion beam apparatus for processing a TEM sample according to claim 1, wherein the mark on the sample surface is formed by spraying a source gas and irradiating an electron beam.

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