KR20200082299A - Apparatus and method for observing specimen - Google Patents

Abstract

The present invention relates to a device for observing a specimen under atmospheric pressure using an electron beam and a method for observing a specimen using the same. The device comprises: a column unit facing a support unit capable of supporting a specimen, having a vacuum space formed therein, and having one side opened toward the support unit; an electron beam generation unit installed inside the column unit; a cover unit coupled to the opening of the column unit and having a transmission window through which an electron beam and electrons may pass; and a bias electrode unit installed on the cover unit to surround the outside of the transmission window. The device and the method may prevent deformation of the specimen and improve resolution of a specimen image.

Description

Sample observation device and method{APPARATUS AND METHOD FOR OBSERVING SPECIMEN}

The present invention relates to a sample observation device and method, and more particularly, to a sample observation device and method that can prevent the deformation of the sample and increase the resolution of the sample image.

Scanning Electron Microscope is a device used for image generation and component analysis of samples. Scanning electron microscopes are widely used in the process of inspecting samples in manufacturing fields such as display devices, solar cells, and semiconductor chips.

When observing a sample at atmospheric pressure with a scanning electron microscope, a bias power must be applied to the sample in order to reach back scattered electrons and secondary electrons emitted from the sample to the scanning electron microscope.

Therefore, there is a difficulty in contacting the substrate and the bias electrode and applying a bias power to the substrate when observing the substrate on which the electronic device is formed. And when the bias electrode is brought into contact with the substrate, the substrate may be deformed. In addition, there is a problem that the substrate may be deformed by a bias power applied to the substrate.

In addition, a sample in which a bias power source cannot be applied, such as a non-conductive sample, cannot accelerate secondary electrons emitted from the sample toward the scanning electron microscope using the bias power source, and collection of secondary electrons is difficult. Therefore, there is a problem that a high-quality sample image cannot be generated by a scanning electron microscope.

The technology underlying the present invention is published in the following patent documents.

KR 10-2016-0134235 A

The present invention provides a sample observing apparatus and method capable of observing an image of a sample using an electron beam without applying a bias power to the sample under atmospheric pressure.

The present invention provides a sample observation device and method capable of accurately observing an image of a sample regardless of the electrical properties of the sample.

The sample observing apparatus according to the embodiment of the present invention is a sample observing apparatus for observing a sample in atmospheric pressure using an electron beam, and is arranged to face a support portion capable of supporting the sample, and a vacuum space is formed therein. A column portion on which one side toward the support portion is opened; An electron beam generator installed inside the column unit; A cover portion coupled to the opening of the column portion and having an electron beam and a transmission window through which electrons can pass; And a bias electrode portion installed on the cover portion to surround the outside of the transmission window.

The cover portion, the through-hole formed in the center, coupled to the opening of the column portion, the main body capable of collecting the electrons emitted from the sample by the electron beam incident; And a collection body coupled to the through hole and capable of collecting the electrons emitted from the sample by electron beam incidence, wherein the collection body is formed with the transmission window at the center and coupled with the bias electrode unit. Can.

The bias electrode portion may be coupled to the peripheral portion of the collection body through an insulating film.

The bias electrode portion, the electrode member is provided on one side of the cover portion facing the support portion, and surrounds the outside of the transmission window; And a bias power supply connected to the electrode member.

The electrode member may be spaced apart from the support.

The electrode member may be formed in a plate shape, and a central portion may penetrate the electron beam traveling direction.

The electrode member may include a metal material.

A sample observation method according to an embodiment of the present invention is a sample observation method for observing a sample at atmospheric pressure, the method comprising: preparing a sample at atmospheric pressure to face a column portion having a vacuum therein; A process of generating an electric field curtain around an electron beam emission region formed in an opening of the column portion and formed under the transmission window facing the sample; Emitting an electron beam toward the sample along the electron beam emission region; A process of collecting electrons emitted from the sample after the electron beam incident on the sample collides with the sample; Detecting a current caused by the electrons; And processing the detected current to generate a sample image.

The process of generating the electric field curtain includes applying a bias voltage to an electrode member installed to surround the outside of the transmission window and spaced apart from the sample; Forming an electron passage surrounded by the electric field curtain directly under the transmission window; And a process of electrically polarizing the gas in the electron passage extending in the electron beam traveling direction.

In the process of applying the bias voltage, in the process of forming a potential difference between the electrode member and the sample, forming an electric field curtain surrounding the outside of the transmission window between the electrode member and the sample, and forming the electron passage , The electron passage may be brought into contact with the sample.

The process of collecting the electrons includes: collecting the electrons to the center of the electron passage and pulling them toward the transmission window; And obtaining electrons emitted from the sample through the electron passage.

And forming an inert gas atmosphere in a space between the sample and the transmission window.

According to the embodiment of the present invention, the image of the sample can be observed using an electron beam without applying a bias power to the sample under atmospheric pressure. That is, without contacting the bias electrode part to the sample, the image of the sample can be observed using an electron beam, and the image of the sample can be accurately observed regardless of the electrical properties of the sample.

More specifically, an electric field curtain may be formed between the bias electrode portion and the sample by forming a bias electrode portion around the outside of the transmission window through which the electron beam passes, and applying a bias voltage to the bias electrode portion at a predetermined voltage. Accordingly, an electron passage can be formed in a space surrounded by an electric field curtain directly under the transmission window, and secondary electrons and backscattered electrons emitted from the sample can be smoothly and efficiently collected through the electron passage. In particular, secondary electrons having a low energy level can be smoothly collected with high efficiency.

Thus, since secondary electrons and backscattered electrons can be smoothly collected through the electron passage, there is no need to apply a bias power to the sample. Therefore, it is possible to prevent mechanical contact between the sample and the bias electrode portion. Accordingly, it is possible to prevent the deformation of the physical shape and electrical properties of the sample by the bias electrode part and the bias power source.

In addition, the sample image can be precisely observed regardless of the electrical properties of the sample. For example, secondary electrons and backscattered electrons emitted from a non-conductive sample can be smoothly collected and generated as a high-quality sample image.

In addition, since the electric field curtain and the electron passage have the effect of collecting and pulling the secondary electrons, the secondary electrons can be smoothly and efficiently collected through the electron passage. Since the secondary electrons smoothly collected with high efficiency can be used to generate a sample image, the resolution of the sample image can be increased.

1 is a schematic diagram of a sample observation device according to an embodiment of the present invention.
2 is a partially enlarged view of a sample observation device according to an embodiment of the present invention.
3 is a schematic diagram of an electric field curtain and an electron passage according to an embodiment of the present invention.
4 is a schematic diagram of a cover portion according to an embodiment of the present invention.
5 is a flowchart of a method for observing a sample according to an embodiment of the present invention.
6 and 7 are photographs showing results of observing a sample by applying a sample observing apparatus and method according to embodiments and comparative examples of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and will be implemented in various different forms. Only the embodiments of the present invention are provided to make the disclosure of the present invention complete, and to fully inform the scope of the invention to those skilled in the art. The drawings may be exaggerated to describe embodiments of the present invention, and the same reference numerals in the drawings refer to the same elements.

1 is a schematic view of a sample observation device according to an embodiment of the present invention, and FIG. 2 is a partially enlarged view of a sample observation device according to an embodiment of the present invention. 3 is a schematic view of an electric field curtain and an electron passage according to an embodiment of the present invention, and FIGS. 4A and 4B are schematic views of a cover part according to an embodiment of the present invention.

The sample observation apparatus and method according to an embodiment of the present invention, when observing a sample at atmospheric pressure using an electron beam, can generate a high-quality sample image without contacting the bias electrode portion to the sample. Therefore, the sample observing apparatus and method according to an embodiment of the present invention may be referred to as a non-contact sample observing apparatus and method.

1 and 2, a sample observation device according to an embodiment of the present invention will be described.

The sample observation device according to the embodiment of the present invention is disposed to face the support portion 20 capable of supporting the sample 10, a vacuum space is formed therein, and a column portion having one side open toward the support portion 20 is opened (100), the electron beam generating unit 200 installed inside the column unit 100, coupled to the opening 110 of the column unit 100, and provided with a transmission window 330A through which the electron beam and electrons can pass It includes a cover portion 300, and a bias electrode portion 400 provided on the cover portion 300 to surround the outside of the transmission window (330A).

In addition, the sample observation device may include detection units 500, 600, and 700 that detect current generated by electrons passing through the transmission window 330A. Here, the detection unit may include a first detection unit 500, a second detection unit 600, and a third detection unit 700.

The sample 10 may be a wafer or glass panel used for manufacturing various electronic devices in a process in which various display devices including LCD, OLED and LED, solar cells and semiconductor chips are manufactured.

Of course, the sample 10 is not particularly limited to the above, and includes various organic materials or inorganic materials or mixtures thereof prepared in a solid state or a liquid phase or a mixed state of a solid phase and a liquid phase in a standard atmospheric pressure regardless of size or shape. It can be a sample in a broad sense.

The sample 10 may include an electrically conductive material. Further, the sample 10 may include a non-conductive material. That is, the electrical properties of the sample 10 may be varied.

The support 20 may be formed in a plate type corresponding to the size and shape of the sample 10. The support part 20 may be positioned to face the opening 110 of the column part 100. Specifically, the support part 20 may be located below the opening 110 of the column part 100. The support part 20 may be formed in a predetermined shape and size capable of supporting the sample 10. The configuration and method of the support 20 may be varied. The support 20 may be various stages capable of supporting the sample 10 at atmospheric pressure. Separate lift pins (not shown) and clamps (not shown) may be provided on the support 20. On the other hand, in the embodiment of the present invention, since it is not necessary to apply a bias power to the sample 10, the structure of the support 20 may be simple.

The column unit 100 may be disposed to face the support unit 20. The column unit 100 may be spaced a predetermined height upward from the support unit 20. The column part 100 may face the support part 20 in the vertical direction, for example. A vacuum space may be formed in the column unit 100. The column portion 100 may have one side toward the support portion 20 open. More specifically, the column unit 100 may be formed with an opening 110 at the bottom.

The column unit 100 may extend in the vertical direction. The column unit 100 may be a vacuum container of various shapes satisfying that the electron beam generating unit 200 can be accommodated therein. The column unit 100 may include stainless steel (SUS) material. The inside of the column unit 100 may be controlled with a vacuum of a predetermined size, for example, about 10 ^-5 to 10 ^-7 torr for generating and accelerating the electron beam.

The opening 110 may have a hollow cylindrical shape. The opening 110 may be formed with a thread on the outer circumferential surface. The cover portion 300 can be easily detached from the thread.

The column unit 100 may be electrically grounded. The electrons emitted from the sample 10 may be concentrated in the upper body 311 of the collecting body 320 and the main body 310 described later of the cover part 300.

The electron beam generating unit 200 may be installed inside the column unit 100 to face the support unit 20. The electron beam generation unit 200 may generate an electron beam inside the column unit 100 and accelerate the electron beam. The electron beam generator 200 may include an electron emitter 210 and a plurality of lenses 220 and 230. The electron emitter 210 may be disposed on the column portion 100 to emit an electron beam toward the opening 110. The plurality of lenses may be disposed between the electron emitter 210 and the opening 110 to focus and accelerate the electron beam.

The electron emitter 210 may include an electron gun. The electron gun may emit electrons with an accelerating voltage and a probe current of a desired size by using any one of a field emission method and a heat emission method. Specifically, the electron emitter 210 may include a field emission type Schottky electron gun.

The plurality of lenses may include a focusing lens 220 and an objective lens 230. The plurality of lenses may collect electron bundles emitted from the electron emitter 210 using electromagnetic force. In the direction from the electron emitter 210 toward the opening 110, the focusing lens 220 and the objective lens 230 may be arranged in this order.

The electron beam generator 200 includes an aperture through which an electron beam passes (aperture, not shown), an aberration correction electromagnet (stigmator, not shown) that controls aberration of the electron beam, and a scanning coil (not shown) that corrects the deflection of the electron beam. ), and a predetermined controller (not shown) connected to the electron beam generator 120 to control the generation and acceleration of the electron beam by the electron beam generator 120.

The cover part 300 is mounted to the opening 110 of the column part 100 and can maintain the internal vacuum of the column part 100. At this time, the cover unit 300 may pass electron beams, backscattered electrons and X-rays, and collect secondary electrons. Meanwhile, the secondary electrons may be electrons having an energy of several tens to hundreds of eV, and the backscattered electrons may be electrons having greater energy than the secondary electrons.

Referring to FIG. 2, the cover part 300 is coupled to the opening 110 of the column part 100 and the main body 310 through which the through hole H1 is formed in the center portion, and the sample 10 by electron beam incident It may include a collection body 320 coupled to the through-hole (H1) to collect the electrons emitted from, and a transmission window (330A) formed in the center of the collection body (320).

In addition, the cover portion 300, the coupling member 340 for detachably coupling the main body 310 to the opening 110 of the column portion 100, and the main body 310 of the column portion 100 It may include an insulating sealing ring 350 provided between the main body 310 and the column portion 110 to be tightly coupled to the opening (110).

The main body 310 may be detachably coupled to the opening 110 of the column part 100 by the joint member 340. The main body 310 is a body of the cover part 300, and the entire shape may be a disk shape. The main body 310 may include an electrically conductive layer and at least one insulating layer mutually stacked in the electron beam traveling direction. The electron beam traveling direction may be, for example, up and down.

Specifically, the main body 310 may include an upper layer 311, an intermediate layer 312, and a lower layer 313 stacked and coupled in the vertical direction. Here, the upper layer 311 and the lower layer 313 may be an electrically conductive layer, and the intermediate layer 312 may be an insulating layer. The upper layer 311 and the lower layer 313 may include, for example, a stainless steel material. A portion of secondary electrons that have passed through the transmission window 330A may be collected in the upper layer 311. The upper layer 311 may contact the collection body 320 and the first detection unit 500 to form an electron transmission path. Secondary electrons collected in the collection body 320 and the upper layer 311 may be detected by the first detection unit 500.

The intermediate layer 312 may be provided as an integral member or may be provided as a separate plurality of members to be radially disposed. The intermediate layer 312 may include, for example, rubber and plastic materials. The upper layer 311 and the lower layer 313 may be electrically insulated by the intermediate layer 312. Secondary electrons collected from the collection body 320 may be transferred to the upper layer 311 without loss.

A through hole H1 may be formed to penetrate the center of the main body 310. At this time, the upper layer 311 and the lower layer 312 may be convex in the vicinity of the center. In addition, the upper layer 311 and the lower layer 313 may have a structure in which the vicinity of the center is inclined downward toward the collection body 320. A through end near the center of the upper layer 311 may be surrounded by a through end near the center of the lower layer 313. The through end near the center of the upper layer 311 may be exposed downward from the inside of the through end near the center of the lower layer 313.

A separation space H2 may be formed between a through end near the center of the upper layer 311 and a through end near the center of the lower layer 313. A gas injection port 360A, which will be described later, may be located in the separation space H2. The separation space H2 may temporarily receive an inert gas injected from the gas injection port 360A to serve as a buffer.

The collecting body 320 may be coupled to the through hole H1 of the main body 310 in a manner that is adhered to or bonded to the through end near the center of the upper layer 311, and seals the through hole H1. . The collection body 320 may be electrically connected to the upper layer 311.

The collection body 320 may have various shapes, including a disc shape and a square plate shape. Collection body 320 may be of an electrically conductive material. The collection body 320 may be, for example, a silicon wafer including a silicon (Si) single crystal material doped to have electrical conductivity, or a conductive wafer including a silicon carbide (SiC) wafer or a graphite (C) wafer. The collection body 320 can smoothly collect electrons, for example secondary electrons, emitted from the sample 10 by an electron beam incident on the sample 10 at atmospheric pressure. Secondary electrons collected in the collection body 320 may be detected by the first detection unit 500 through the upper layer 311.

The transmission window 330A may pass an electron beam and electrons, and maintain an internal vacuum of the column unit 100. The transmission window 330A may allow an electron beam to pass through the outside of the column unit 100. The transmission window 330A may pass back scattered electrons and X-rays generated from the sample 10 into the column unit 100. The transmission window 330A may pass or collect secondary electrons generated from the sample 10 into the column 100. Since backscattered electrons (BSE) and X-rays have more energy than secondary electrons, they may pass through the transmission window 330A and reach the second detection unit 600 and the third detection unit 700. The secondary electron has a small energy and is difficult to reach the second detection unit 600. Therefore, the secondary electron SE can be smoothly collected using the collection body 320. The secondary electrons collected by the collection body 320 may be used to generate a high-resolution sample image in the first detection unit 500.

The transmission window 330A may include a membrane having a thin thickness. Specifically, the transmission window 330A may include, for example, a silicon nitride (SiN) film having a thickness of 100 nm or less, and specifically 3 to 100 nm. The transmission window 330A may be formed at the center of the collection body 320.

The process of forming the transmission window 330A in the center of the collection body 320 will be briefly described. A transparent thin film 330 such as a silicon nitride film is formed on one surface of the collecting body 320. The via hole is etched in the center of the collecting body 320 in a direction from the other surface of the collecting body 320 on which the transparent thin film 330 is not formed, toward the aforementioned one surface of the collecting body 320. A transmission window 330A may be formed in the center of the collection body 320 by the via hole. Of course, the method of forming the transmission window 330A may be various.

The joint member 340 may be in the shape of a hollow cylindrical body, the inside of which is opened in the vertical direction. The main body 310 is seated on the inner circumferential surface of the joint member 340 and may be fitted. The joint member 340 may have a larger thickness in the vertical direction than the main body 310.

A protruding end may be formed at a lower portion of the inner circumferential surface of the joint member 340. The protruding end may extend in the circumferential direction along the inner circumferential surface of the joint member 340. The main body 310 may be seated at the protruding end. Threads may be formed on the inner circumferential surface of the joint member 340. The joint member 340 may be screwed to the opening 110 of the column part 110 through a thread. The joint member 340 may include a stainless steel material or a plastic material.

The insulating sealing ring 350 may be, for example, an O-ring. The insulating sealing ring 350 may be provided between the upper layer 311 of the main body 310 and the opening 110 of the column part 100. The main body 310 may be coupled to the opening 110 of the column part 100 through the insulating sealing ring 350. The insulating sealing ring 350 may insulate and seal between the main body 310 and the column portion 100.

The cover part 300 may include a gas injection hole 360A for injecting gas downward and a gas path 360 connected to the gas injection hole 360A to supply gas.

2 and 4, the gas path 360 may extend toward a gas injection port 360A between a plurality of layers of the main body 310. Specifically, the gas path 360 may extend through the intermediate layer 312, may be spaced apart from the upper layer 311 and the lower layer 313, or may be covered with an insulating film. The gas path 360 may be connected to a gas supply source (not shown) provided outside the cover part 300 to receive gas.

Of course, in addition to this, the gas path 360 may be formed in various structures. For example, when the intermediate layer 312 is provided radially and is provided with a plurality of separate members, the gas path 360 may be a separation space formed between the upper layer 311, the lower layer 313, and the intermediate layer 312.

The gas injection hole 360A may be provided at a through end of the main body 310 facing the collection body 320 side. For example, the gas injection port 360A may be an end portion of the gas path 360 extending downwardly in a direction toward a lower center of the collecting body 320 between the through end of the upper layer 311 and the through end of the lower layer 313. have.

A plurality of gas injection holes 360A may be formed, and may be radially disposed around the collection body 320. Thus, the gas injection port 360A may create an inert gas atmosphere locally at the lower side of the collection body 320 by spraying an inert gas at 360° all over the collection body 320. The inert gas may be, for example, at least one gas selected from helium (He), neon (Ne), and argon (Ar).

When the gas path 360 is formed as a separation space formed between the upper layer 311, the lower layer 313, and the intermediate layer 312, the gas injection port 360A includes the through end of the upper layer 311 and the lower layer 313. It may be an annular spacing space formed between the through ends.

Referring to FIG. 2, the bias electrode part 400 may be installed on the cover part 300 to surround the outside of the transmission window 330A. The bias electrode part 400 is installed on one surface of the cover part 300 and is provided to the electrode member 410 through the electrode member 410 surrounding the outside of the transmission window 330A and the bias power supply line 430. It may include a bias power supply 420 to be connected.

The electrode member 410 may be coupled to the periphery of the collection body 320 through the insulating film 411. Specifically, the electrode member 410 may be installed on the lower surface of the transparent thin film 330 by surrounding the outside of the transparent window 330A. At this time, an insulating film 411 may be provided between the electrode member 410 and the transparent thin film 330. The central portion of the insulating film 411 may be penetrated in the electron beam traveling direction. The transparent window 330A may be exposed through the center of the insulating film 411. The electrical connection between the electrode member 410 and the collecting body 320 may be insulated by the insulating film 411.

The electrode member 410 may be formed in a disc or square plate shape. For example, when the collection body 320 is in the shape of a disc, the electrode member 410 may be formed in a disc shape. The electrode member 410 may be a thin metal film. The center of the electrode member 410 may be penetrated in the electron beam traveling direction. Through the center of the electrode member 410, the transmission window 330A may be exposed to the sample 10. The electrode member 410 may be spaced apart from the support 20. In addition, the electrode member 410 may be spaced apart from the sample 10 on the support 20.

The electrode member 410 may include an electrically conductive metal material. For example, the electrode member 410 may include an aluminum material. The bias power supply 420 may apply a bias voltage of tens to hundreds of volts (V) to the electrode member 410. At this time, the bias voltage may be a negative voltage.

2 and 3, the electrode member 410 is supplied with a bias voltage to the electric field curtain E surrounding the outside of the transmission window 330A and the electric field curtain E directly under the transmission window 330A. An enclosed electron passage can be formed.

The space B between the transmission window 330A and the sample 10 may include an electron beam emission region A and its circumferential region C, and an electric field curtain E may be formed in the circumferential region C. The electron passage may be formed in the electron beam emission region A. The electron passage may extend along the electron beam traveling path to contact the sample 10, and the electric field curtain E may electrically polarize the gas in the electron passage. At this time, the outer diameter of the electric field curtain E may be several mm. In addition, the outer diameter of the electron passage may be hundreds of μm, and the height may be several tens to several hundreds of μm.

When an electron beam is incident on the sample 10, backscattered electrons (BSE), X-rays, and secondary electrons are emitted from the sample 10. Backscattered electrons and X-rays pass through the transmission window 330A made of silicon nitride (SiN) and are incident into the column 100. At this time, the spot size of the electron beam incident on the sample 10 may be on the order of several nm.

The secondary electrons are partially absorbed by the silicon nitride (SiN)-transmitting window 330A and collected by the silicon (Si) single crystal material collecting body 320, and the rest are silicon nitride (SiN)-transmitting windows. Passed through (330A) is collected directly in the collection body (320).

At this time, the electric field curtain E and the repulsive force f1 of the secondary electrons may be formed in a direction toward the center of the electron passage. That is, the electric field curtain E can prevent secondary electrons from spreading out of the electron passage. By the repulsive force f1 described above, secondary electrons emitted from the sample 10 may be collected in the center of the electron passage. Further, the gas that is electrically polarized in the electron passage may pull secondary electrons collected at the center of the electron passage toward the transmission window 330A. For example, gas molecules having polarized polarities may be polarized by an electric field curtain (E) in an electron passage to function as a wire moving secondary electrons. Accordingly, a force f2 that pulls secondary electrons upward may be formed inside the electron passage. Therefore, secondary electrons having a low energy level can be smoothly collected into the transmission window 330A along the electron passage.

Secondary electrons collected in the transmission window 330A and the collection body 320 cause current, and the first detection unit 500 may detect it. At this time, an inert gas atmosphere may be locally formed in a space D of, for example, 200 μm or less in width, formed between the transmission window 330A and the sample 10, whereby secondary electrons can be smoothly collected into the collection body Can.

In observing the image of the sample 10, in the case of forming the electric field curtain E and the electron passage below the transmission window 330A, the electric field curtain E and the electron passage are formed below the transmission window 330A. The resolution of the image may be increased by, for example, 5 to 10 times as compared to the case where it is not.

The first detection unit 500 may be connected to the cover unit 300 and detect a current generated by electrons passing through the transmission window 330A. The first detection unit 500 is in contact with the contact needle 510, which can contact the main body 310 or the collection body 320 to detect the current generated by the electrons collected in the cover unit 300, contact It may include a signal processor 530 connected to the needle 510, a transmission line 520 for transmitting current, and a signal processor 530 for processing the detected current to form an image.

The contact needle 510 may be contact-connected to the upper layer 311 of the main body 310 of the cover part 300 inside the column part 100. Of course, the contact position of the contact needle 510 may vary. The transmission line 520 may partially pass through the column part 100, one end may be connected to the contact needle 510, and the other end may be connected to the signal processor 530. The transmission line 420 may include an insulating insulating line.

The signal processor 530 may process the detected current to form an image. For example, the observation target region of the sample 10 located under the transmission window 330A is divided into a plurality of pixels, and an electron beam is scanned into any one of the plurality of pixels. When electrons are emitted from the sample 10 by the electron beam and collected in the collection body 320, current caused by the collected electrons is detected. The detected current is amplified and processed by the signal processor 530 and selectively output as an image signal corresponding to the brightness value of the corresponding pixel. By repeating the above-described process, it is possible to form an image signal of each of a plurality of pixels, from which it is possible to form an image of a region to be observed of the sample 10.

The second detection unit 600 may collect backscattered electrons scattered into the column unit 100 and transmit them to the signal processor 530. The second detection unit 600 may be, for example, a semiconductor detector provided in a predetermined plate shape. The second detection unit 600 may be aligned in the vertical direction to the collection body 320 of the cover unit 300 in the column unit 100. The second detection unit 600 may be formed with a passage through which the central portion penetrates in the vertical direction and through which the electron beam can pass.

The second detection unit 600 acquires backscattered electrons incident into the column unit 100 and transfers the current caused by the backscattered electrons to the signal processor 530 to be used for image generation.

The third detection unit 700 may collect X-rays scattered into the column unit 100 to inspect the components of the sample 10 therefrom. The third detection unit 700 includes, for example, an energy dispersive X-ray spectroscopy detector (EDS Detector), a part of which penetrates the column unit 100, the end of which is inside the column unit 100 It may be arranged to face the transmission window 330A of the cover portion 300. The energy dispersive spectroscopic detector detects X-ray energy obtained from the sample 10 by scanning an electron beam in the form of energy using a pin semiconductor element of silicon single crystal, so that the surface component of the sample 10 can be inspected Can be formed. The third detection unit 700 may be connected to a data processor (not shown). The data processor compares the energy intensity data of the X-rays output from the third detection unit 700 and the detection frequency data of each energy intensity with the emission X-ray intrinsic energy size data of each component, and extracts the components of the sample 10. It can be quantitatively and qualitatively analyzed and output as visual information.

5 is a flowchart of a method for observing a sample according to an embodiment of the present invention.

Hereinafter, a sample observation method according to an embodiment of the present invention will be described.

Referring to Figure 5, the sample observation method according to an embodiment of the present invention, the process of preparing the sample 10 in the atmospheric pressure so as to face the column portion 100 with a vacuum formed therein, the opening of the column portion 100 ( The process of generating an electric field curtain (E) in the circumferential region (C) of the electron beam emission region (A) formed under the transmission window (330A) formed on the sample 10 and facing the sample 10, the electron beam emission region (A) A process of emitting an electron beam toward the sample 10 along, the process of collecting electrons emitted from the sample 10 after the electron beam incident on the sample 10 collides with the sample 10, and the current caused by the electrons And detecting and processing the detected current to generate a sample image.

First, a sample 10 is prepared at atmospheric pressure so as to face the column unit 100 (S100). For example, a sample 10 is loaded on the upper surface of the support 20 using a transfer robot (not shown).

When the sample 10 is provided on the upper surface of the support portion 20, the column portion 100 is positioned to face the sample 10 on the upper side of the sample 10, and at least one of the column portion 100 and the support portion 20 One can be moved up and down, and the space D between the transmission window 330A and the sample 10 can be precisely adjusted within a range of, for example, 200 μm or less.

Thereafter, an electric field curtain E is generated around the electron beam emission region A formed directly under the transmission window 330A (S200). Specifically, a bias voltage of tens to hundreds of volts is applied to the electrode member 410 which is installed to surround the outside of the transmission window 330A and spaced apart from the sample 10, and an electric field curtain under the transmission window 330A ( E) can form an enclosed electron passage, and electrically polarize the gas in the electron passage extending in the electron beam traveling direction.

Here, in the process of applying the bias voltage, an electric potential difference is formed in the space between the electrode member 410 and the sample 10, and the outer side of the transmission window 330A between the electrode member 410 and the sample 10 is formed. The electric field curtain E surrounding the can be formed.

At this time, the sample 10 and the electrode member 410 may be spaced apart, a bias power is not applied to the sample 10, and a bias power may be applied only to the electrode member 410. Therefore, unnecessary contact of the sample observation device with the sample 10 can be prevented.

In the process of forming the electron passage, the electron passage may be brought into contact with the sample 10. Specifically, the upper portion of the electron passage may contact the transmission window 330A, and the lower portion may contact the sample 10.

Thereafter, the electron beam is emitted toward the sample 10 along the electron beam emission region A (S300). More specifically, the electron beam generator 120 emits and accelerates electrons with a predetermined acceleration voltage, such as an acceleration voltage of several tens of kV and a probe current. The accelerated electron beam passes through the cover portion 300 mounted to the opening 110 of the column portion 100 and is controlled to a probe size of several to several hundred nm, and focus can be formed at a desired location on the sample 10. . At this time, the focus of the electron beam can be precisely adjusted to a height in the range of several to hundreds of μm from a predetermined position spaced downward from the transmission window 330A, and the electron beam can be collided by emitting an electron beam at a desired position.

Thereafter, after the electron beam incident on the sample 10 collides with the sample 10, electrons emitted from the sample 10 are collected in an atmospheric pressure atmosphere (S400). At this time, electrons can be collected at the center of the electron passage, pulled toward the transmission window 330A, and electrons emitted from the sample 10 can be obtained through the electron passage.

The electrons emitted from the sample 10 by the electron beam incident on the sample 10 have a directionality by a relatively high energy level, and are backscattered straight in a predetermined direction, for example, from the sample 10 toward the column 100 It can contain the former. In addition, the electrons emitted from the sample 10 may include secondary electrons having a relatively low energy level than backscattered electrons.

In this process, as the secondary electrons are collected through the electron passage, scattering of the secondary electrons can be suppressed or prevented, and more secondary electrons can be collected.

A specific process of acquiring electrons emitted from the sample 10 may include a process of collecting secondary electrons in the transmission window 330A and a process of collecting backscattered electrons inside the column unit 100.

That is, secondary electrons acquired through the transmission window 330A are collected in the upper layer 311 of the collecting body 320 and the main body 310, and the collected secondary electrons pass through the upper layer 311 and are first It may be electrically transmitted to the detection unit 500.

Backscattered electrons emitted from the sample 10 may be collected by the second detection unit 600. For example, the backscattered electrons are collected by the second detection unit 600 through the transmission window 330A of the cover unit 300, and the second detection unit 600 electrically collects the collected backscattered electrons to the signal processor 530. Can deliver.

Then, the current caused by the obtained electrons is detected (S500). That is, secondary electrons and backscattered electrons are detected by the first detection unit 500 and the second detection unit 600.

Thereafter, the detected current is processed to generate a sample image (S600). Specifically, the current caused by secondary electrons and backscattered electrons is added to convert to an image. The signal processor 530 may convert a signal from the collected secondary electrons and a signal from the collected backscattered electrons into an image. Since a known technique can be applied to the process and method of forming an image from the detected current, detailed description thereof will be omitted.

Meanwhile, the method for observing a sample according to an embodiment of the present invention may include a process of forming an inert gas atmosphere in a space between the sample 10 and the transmission window 330A. For example, the inert gas is injected from the gas injection port 360A, and the space D between the transmission window 330A and the sample 10 is formed in an inert atmosphere, so that secondary electrons can be easily collected with high efficiency.

6 and 7 are pictures showing a result of observing a sample using a sample observation device according to an embodiment and a comparative example of the present invention. Here, the sample observation device according to the comparative example of the present invention may be a sample observation device in a state in which the bias electrode is removed from the sample observation device according to the embodiment of the present invention.

6(a) and 6(b), it can be seen that the foreign matter (dotted circle) estimated to be an organic material appears as a clear image and clearly distinguished from the metal pattern. On the other hand, looking at (a) and (b) of Figure 7, it can be seen that the foreign matter presumed to be organic is darkly expressed, and the boundary between the foreign material and the metal pattern is also unclear. For this reason, in the comparative example of the present invention, the secondary electrons cannot be collected smoothly, and thus only the backscattered electrons can be used to generate an image of the sample. Because there is.

For reference, as a sample observing apparatus according to a comparative example of the present invention, except for the current obtained at the second detection unit for detecting backscattered electrons, the sample image at the current obtained by the first detection unit for detecting secondary electrons When generating, you could only get a gray screen with no signal. That is, according to the comparative example of the present invention, since the sample observation device does not collect secondary electrons and can collect only backscattered electrons, the amount of detection signal is small and thus a low-quality sample image as shown in FIGS. You can see that it creates

On the other hand, according to an embodiment of the present invention, since the sample observation device can smoothly collect secondary electrons, it can be confirmed that high-quality sample images can be obtained as shown in FIGS. 6A and 6B. On the other hand, in the case of the embodiment, since the sample observation device collects secondary electrons and generates them as an image, it is possible to obtain a high-quality image regardless of the composition of the object to be observed, for example, a sample.

The above embodiments of the present invention are for the purpose of describing the present invention and not for the limitation of the present invention. It should be noted that the configurations and methods disclosed in the above embodiments of the present invention may be modified in various forms by combining or crossing each other, and such modified examples can be seen as the scope of the present invention. That is, the present invention will be implemented in a variety of different forms within the scope of the claims and equivalent technical spirit, and various embodiments are possible within the scope of the technical spirit of the present invention. Will be able to understand.

100: column unit 200: electron beam generating unit
300: cover portion 400: bias electrode portion
410: electrode member 500: first detection unit
600: second detection unit 700: third detection unit

Claims (12)

A sample observing apparatus for observing a sample at atmospheric pressure using an electron beam,
A column portion disposed to face a support portion capable of supporting the sample, a vacuum space formed therein, and one side toward the support portion being opened;
An electron beam generator installed inside the column unit;
A cover portion coupled to the opening of the column portion and having an electron beam and a transmission window capable of passing electrons; And
Sample observation device comprising a; bias electrode portion provided on the cover portion to surround the outside of the transmission window. The method according to claim 1,
The cover portion,
A main body through which a through-hole is formed in the center, coupled to the opening of the column portion, and capable of collecting the electrons emitted from the sample by electron beam incidence; And
It includes; a collection body coupled to the through-hole and capable of collecting the electrons emitted from the sample by electron beam incidence;
The collection body, the transmission window is formed in the center, the sample observation device coupled to the bias electrode portion. The method according to claim 2,
The bias electrode unit is a sample observation device coupled to the peripheral portion of the collection body through an insulating film. The method according to claim 1,
The bias electrode portion,
An electrode member installed on one surface of the cover portion facing the support portion and surrounding the outside of the transmission window;
A sample observation device comprising a; bias power supply connected to the electrode member. The method according to claim 4,
The electrode member is a sample observation device spaced apart from the support. The method according to claim 4,
The electrode member is formed in a plate shape, the center of the sample observation device through which the electron beam travels. The method according to claim 4,
The electrode member is a sample observation device comprising a metal material. As a sample observation method for observing a sample at atmospheric pressure,
Preparing a sample in atmospheric pressure so as to face a column portion having a vacuum formed therein;
A process of generating an electric field curtain around an electron beam emission region formed in an opening of the column portion and formed under the transmission window facing the sample;
Emitting an electron beam toward the sample along the electron beam emission region;
A process of collecting electrons emitted from the sample after the electron beam incident on the sample collides with the sample;
Detecting a current caused by the electrons; And
The process of detecting the current to generate a sample image; sample observation method comprising a. The method according to claim 8,
The process of generating the electric field curtain,
A process of applying a bias voltage to an electrode member installed to surround the outside of the transmission window and spaced apart from the sample;
Forming an electron passage surrounded by the electric field curtain directly under the transmission window;
A method of observing a sample, comprising: electrically polarizing a gas in the electron passage extending in an electron beam traveling direction. The method according to claim 9,
In the process of applying the bias voltage, an electric potential difference is formed between the electrode member and the sample, and an electric field curtain surrounding the outside of the transmission window is formed between the electrode member and the sample,
In the process of forming the electron passage, a sample observing method for contacting the electron passage with the sample. The method according to claim 9,
The process of collecting the electrons,
A process of collecting the electrons into the center of the electron passage and pulling them toward the transmission window;
Obtaining electrons emitted from the sample through the electron passage; sample observation method comprising a. The method according to claim 8,
The process of forming an inert gas atmosphere in the space between the sample and the transmission window; including a sample observation method.

Images