阅读说明：本技术 原子探针检查装置、场离子显微镜及失真修正方法 (Atom probe inspection apparatus, field ion microscope, and distortion correction method ) 是由 池田隆洋 蔵本明 圷晴子 于 2019-08-02 设计创作，主要内容包括：实施方式提供一种能够对进行试样的原子分布再构成后所得的图像,修正因试样的局部倍率而产生的失真的原子探针检查装置、场离子显微镜及失真修正方法。实施方式的原子探针检查装置具备变动部、检测部、特定部、制作部、推定部及再构成部。变动部使从同一位置脱离的离子在由位置敏感型检测器检测所得的位置发生变动。检测部检测位置信息及飞行时间。特定部特定出元素。制作部于在第1条件下检测出的二维位置、及在与第1条件不同的第2条件下检测出的二维位置,根据位置信息及飞行时间制作各再构成图像。推定部根据第1条件及第2条件各自的再构成图像的对应关系,推定与实际位置相关的信息。再构成部基于推定信息,再构成反映出实际原子配置的图像。(An embodiment provides an atom probe inspection apparatus, a field ion microscope, and a distortion correction method capable of correcting distortion caused by a local magnification of a sample with respect to an image obtained by reconstructing an atomic distribution of the sample. The atom probe inspection apparatus of an embodiment includes a variation unit, a detection unit, a specification unit, a production unit, an estimation unit, and a reconfiguration unit. The changing unit changes the position of the ion deviated from the same position, which is detected by the position sensitive detector. The detection unit detects position information and flight time. The specific portion specifies an element. The creation unit creates each reconstructed image based on the position information and the flight time, at the two-dimensional position detected under the 1 st condition and at the two-dimensional position detected under the 2 nd condition different from the 1 st condition. The estimation unit estimates information related to the actual position based on the correspondence relationship between the reconstructed images according to the 1 st condition and the 2 nd condition. The reconstruction unit reconstructs an image reflecting the actual arrangement of atoms based on the estimation information.)

1. An atom probe inspection apparatus includes:

a changing unit that changes a two-dimensional position of ions that have deviated from the same position on the sample surface, the two-dimensional position being detected by a detection surface of a position sensitive detector;

a detection unit that detects two-dimensional position information of the ion detected by the detection surface and a flight time of the ion from the sample to the detection surface;

a specifying unit that specifies an element of the ion detected by the detection surface based on the flight time detected by the detection unit;

a creating unit that creates reconstruction images based on the two-dimensional position information of the ion detected by the detecting unit and the flight time of the ion, at least at a two-dimensional position of the ion detected by the detecting surface under the 1 st condition and a two-dimensional position of the ion detected under the 2 nd condition that is changed by the changing unit so as to be detected at a position different from the position detected by the detecting surface under the 1 st condition;

an estimation unit configured to estimate information on an actual position of the ion on the sample surface after the separation based on a correspondence relationship between the reconstructed images under the 1 st condition and the 2 nd condition; and

and a reconstruction unit that reconstructs an image reflecting the actual arrangement of atoms on the surface of the sample, based on the information estimated by the estimation unit.

2. The atom probe inspection apparatus according to claim 1, further comprising a matching unit that performs feature value matching on the reconstructed images created by the creating unit and corresponding to the 1 st condition and the 2 nd condition, respectively,

the estimating unit estimates information on an actual position of the sample surface of the ion after the ion separation based on a result of the feature value matching by the matching unit.

3. The atom probe inspection apparatus according to claim 1, further comprising: a power supply for applying a voltage to the sample to form an electric field between the sample and the position-sensitive detector; and

and a laser device for irradiating the sample with laser light to cause atoms on the surface of the sample to be dissociated as ions by electric field evaporation.

4. The atom probe inspection apparatus according to any one of claims 1 to 3, wherein the varying unit is a 1 st position control unit that controls movement of the position sensitive detector such that a distance between the specimen and the position sensitive detector varies,

the creation unit creates the reconstructed image at a 1 st position that is the 1 st condition after the 1 st position control unit moves the position sensitive detector, and the 1 st position control unit moves the position sensitive detector to a 2 nd position that is the 2 nd condition different from the 1 st position and creates the reconstructed image at the 2 nd position.

5. The atom probe inspection apparatus according to any one of claims 1 to 3, further comprising a reflection lens that turns back an orbit of an ion desorbed from the sample by an electric field formed and makes the ion fly toward the position sensitive detector,

the changing part is a 2 nd position control part for controlling the position of the reflection lens,

the creation unit creates the reconstructed image at a 1 st position that is the 1 st condition after the 2 nd position control unit moves the reflection lens, and the 2 nd position control unit moves the reflection lens to a 2 nd position that is the 2 nd condition different from the 1 st position and creates the reconstructed image at the 2 nd position.

6. The atom probe inspection apparatus according to any one of claims 1 to 3, further comprising an electromagnetic lens that changes an orbit of an ion desorbed from the sample by a magnetic field formed by the electromagnetic lens,

the varying unit is a lens control unit for controlling the magnetic field forming operation of the electromagnetic lens,

the creation unit creates the reconstructed image when the lens control unit sets the magnetic field formed by the electromagnetic lens to be in the state of the specific magnetic field of the 1 st condition, and creates the reconstructed image when the lens control unit sets the 2 nd condition different from the 1 st condition to be in the state of the magnetic field formed by the electromagnetic lens.

7. The atom probe inspection apparatus according to any one of claims 1 to 3, wherein the varying section is an electric field control section that controls an electric field forming operation by a drive circuit that forms an electric field so that an orbit of an ion desorbed from the sample is varied by the electric field,

the creation unit creates the reconstructed image when the electric field control unit sets the electric field formed by the drive circuit to be in the state of the specific electric field of the 1 st condition, and creates the reconstructed image when the electric field control unit sets the 2 nd condition different from the 1 st condition to be in the state of the electric field formed by the drive circuit.

8. The atom probe inspection apparatus according to any one of claims 1 to 3, further comprising a reflection lens that turns back an orbit of an ion desorbed from the sample by an electric field formed and makes the ion fly toward the position sensitive detector,

the varying section is a reflection control section for controlling an electric field forming operation of the reflection lens,

the creation unit creates the reconstructed image when the reflection control unit sets the electric field formed by the reflection lens to be in the state of the specific electric field of the 1 st condition, and creates the reconstructed image when the reflection control unit sets the 2 nd condition different from the 1 st condition to be in the state of the electric field formed by the reflection lens.

9. A field ion microscope is provided with:

a changing unit that changes a two-dimensional position of ions that have deviated from the same position on the sample surface, the two-dimensional position being detected by a detection surface of a position sensitive detector;

a detection unit that detects two-dimensional positional information of the ion detected by the detection surface;

a creating unit that creates reconstruction images from the two-dimensional position information of the ion detected by the detecting unit, at least at the two-dimensional position of the ion detected by the detecting surface under the 1 st condition and at least at the two-dimensional position of the ion detected by the 2 nd condition after being varied by the varying unit so as to be detected at a position different from the position detected by the detecting surface under the 1 st condition;

an estimation unit configured to estimate information on an actual position of the ion on the sample surface after the separation based on a correspondence relationship between the reconstructed images under the 1 st condition and the 2 nd condition; and

and a reconstruction unit that reconstructs an image reflecting the actual arrangement of atoms on the surface of the sample, based on the information estimated by the estimation unit.

10. A distortion correction method comprising:

a changing step of changing a two-dimensional position of ions separated from the same position on the surface of the sample, the two-dimensional position being detected by a detection surface of a position sensitive detector;

a detection step of detecting two-dimensional position information of the ion detected by the detection surface and a flight time of the ion from the sample to the detection surface;

a specifying step of specifying an element of the ion detected by the detection surface based on the detected flight time;

a generating step of generating reconstruction images from the two-dimensional position information of the detected ion and the flight time of the ion, at least at a two-dimensional position of the ion detected by the detection surface under the 1 st condition and a two-dimensional position of the ion detected under the 2 nd condition that has been changed so as to be detected at a position different from the position detected by the detection surface under the 1 st condition;

an estimation step of estimating information on an actual position of the sample surface of the desorbed ion based on a correspondence relationship between the reconstructed images under the 1 st condition and the 2 nd condition; and

and reconstructing an image reflecting the actual arrangement of atoms on the surface of the sample based on the estimated information.

Technical Field

Embodiments of the present invention relate to an atom probe inspection apparatus, a field ion microscope, and a distortion correction method.

Background

An Atom Probe Field Ion Microscope (Atom Probe Field Ion Microscope: APFIM) that analyzes the specific and spatial distribution of elements in a sample using the principle of Field Ion Microscope (Field Ion Microscope: FIM) is a device capable of atomic-level composition analysis. The FIM and APFIM are widely used for analysis of a semiconductor sample having a microstructure.

In FIM or APFIM, a sample processed into a needle shape by an FIB (Focused Ion Beam) apparatus is directly applied with a high electric field in vacuum. Then, due to the action of the electric field, 1 atom or a plurality of atomic groups present on the surface of the sample are emitted into the vacuum, and thereafter reach a position sensitive detector placed so as to face the tip end of the sample while being affected by the electric field. Here, the phenomenon in which atoms are ionized by an electric field and then detached from the sample surface is referred to as electric field evaporation. The ion thus emitted can be resolved in which direction the ion flies from the tip of the sample, by solving the equation of motion of the ion in the electric field. This makes it possible to perform a process called reconstruction, which is to calculate the distribution of atoms in the sample corresponding to the detected ions. In such an analysis using FIM or APFIM, there is a problem that a reconstructed image is distorted due to a change in local magnification. The causes of distortion include: the front end does not form a spherical crown shape during sample processing; and the shape of the sample containing a plurality of different materials is changed in the electric field evaporation process, so that the local multiplying power on each position of the surface of the sample is changed.

As such APFIM, a method of moving a position sensitive detector in order to improve the yield of ions evaporated in a radial electric field is known.

However, the position sensitive detector is moved to improve the ion yield, and the distortion of the reconstructed image cannot be corrected.

In addition, a method of improving the image accuracy by combining images obtained by a plurality of apparatuses (for example, TEM (Transmission Electron Microscope) and APFIM) is known.

However, in this method, it is difficult to compare the two samples at the intermediate stage of the electric field evaporation, and samples subjected to different cutting methods are compared with each other, so that when a fine device structure exists inside the sample, a local magnification difference occurs depending on a difference in processing position for each sample. In addition, the error information of the local magnification obtained by this method cannot be reused when the material or structure used in the sample is changed in many cases. Further, since a plurality of different devices are used, the cost for the devices increases, and operations such as positioning between the devices are not easy.

Disclosure of Invention

Drawings

Fig. 1 is a diagram showing an example of the configuration of an atom probe inspection apparatus according to embodiment 1.

Fig. 2 is a diagram illustrating an outline of the operation of the atom probe inspection apparatus according to embodiment 1.

Fig. 3 is a diagram showing an example of a hardware configuration of the controller according to embodiment 1.

Fig. 4 is a diagram showing an example of the configuration of functional blocks of the controller according to embodiment 1.

Fig. 5 is a diagram illustrating a detection operation in a case where the sample shape is a spherical cap shape.

Fig. 6 is a diagram illustrating a case where the sample shape is not the spherical cap shape.

Fig. 7 is a diagram comparing the actual shape of the sample with the reconstructed image.

Fig. 8 is a diagram illustrating the influence of local magnification change.

Fig. 9 is a diagram for explaining an operation of moving the position sensitive detector in embodiment 1.

Fig. 10(a) to (c) are diagrams comparing images detected at 2 positions.

Fig. 11 is a flowchart of the operation of the atom probe inspection apparatus according to embodiment 1.

Fig. 12 is a diagram showing an example of the configuration of an atom probe inspection apparatus according to variation 1 of embodiment 1.

Fig. 13 is a diagram showing an example of the configuration of functional blocks of the controller according to variation 1 of embodiment 1.

Fig. 14 is a diagram illustrating an operation of moving the reflection lens in variation 1 of embodiment 1.

Fig. 15 is a diagram showing an example of an image obtained by FIM.

Fig. 16 is a diagram showing a configuration example of the atom probe inspection apparatus according to embodiment 2.

Fig. 17 is a diagram showing an example of the configuration of functional blocks of the controller according to embodiment 2.

Fig. 18 is a diagram for explaining an operation of changing the orbit by the electromagnetic lens in embodiment 2.

Fig. 19 is a diagram showing an example of the configuration of an atom probe inspection apparatus according to variation 1 of embodiment 2.

Fig. 20 is a diagram showing an example of the configuration of an atom probe inspection apparatus according to variation 2 of embodiment 2.

Fig. 21 is a diagram showing an example of the configuration of functional blocks of a controller according to variation 2 of embodiment 2.

Fig. 22 is a diagram illustrating an operation of changing the trajectory by an electric field in variation 2 of embodiment 2.

Fig. 23 is a diagram showing an example of the configuration of an atom probe inspection apparatus according to variation 3 of embodiment 2.

Fig. 24 is a diagram showing an example of the configuration of functional blocks of a controller according to variation 3 of embodiment 2.

Fig. 25 is a diagram illustrating an operation of changing the orbit by the reflection lens in variation 3 of embodiment 2.

Embodiments provide an atom probe inspection apparatus, a field ion microscope, and a distortion correction method that can correct distortion that occurs with a local magnification of a sample in an image obtained by reconstructing an atom distribution of the sample.

[ means for solving problems ]