# US 2022/0044906 A1 · Charged Particle Beam Device, Autofocus Processing Method of Charged Particle Beam Device, and Detector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0044906 A1 - Document ID: US20220044906A1 - Status: Published application - Kind: A1 - Application number: 17/280,661 - Filed: 2018-10-25 - Published: 2022-02-10 - Earliest claimed: 2018-10-25 - Assignees: Hitachi High-Tech Corporation - Applicants: Hitachi High-Tech Corporation - Inventors: Mitsuhiro NAKAMURA; Michio HATANO - Web page: https://patentgrep.com/patent/US20220044906A1 ## CPC - H01J 37/21: Means for adjusting the focus - H01J 37/20: Means for supporting or positioning the object or the material; Means for adjusting diaphragms or lenses associated with the support - H01J 37/244: Detectors; Associated components or circuits therefor - H01J 37/265: {Controlling the tube; circuit arrangements adapted to a particular application not otherwise provided, e.g. bright-field-dark-field illumination} - H01J 2237/2608: with environmental specimen chamber - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract Provided are a charged particle beam device and a detector capable of non-invasively observing a biochemical sample without a staining treatment or an immobilization treatment, with a simple and high observation throughput. An electron optics system, a stage 64, a sample chamber 100 holding a sample and including a first insulating layer 110 that is in contact with the sample, and a conductive layer 120 that is formed on the first insulating layer, signal detection circuits 20 and 50 connected to the conductive layer and detecting a current flowing through the conductive layer, and a main control unit 14 for controlling the electron optics system and the stage, wherein the main control unit 14 irradiates the conductive layer of the sample chamber placed on the stage with an electron beam from the electron optics system and is input with a detection signal from the signal detection circuit. ## Claims ### Claim 1 A charged particle beam device comprising: an electron optics system; a stage; a sample chamber holding a sample and including a first insulating layer that is in contact with the sample, and a conductive layer formed on the first insulating layer; a signal detection circuit connected to the conductive layer and detecting a current flowing through the conductive layer; and a main control unit for controlling the electron optics system and the stage, wherein the main control unit irradiates the conductive layer of the sample chamber placed on the stage with an electron beam from the electron optics system and is input with a detection signal from the signal detection circuit. ### Claim 2 (depends on 1) The charged particle beam device according to claim 1, wherein the main control unit converts a detection signal from the signal detection circuit into pixel gradation data according to the intensity thereof for each deflection position of an electron beam to the sample chamber. ### Claim 3 (depends on 1) The charged particle beam device according to claim 1, wherein the sample chamber includes a first outer frame portion that supports the first insulating layer, the first outer frame portion includes a first window portion recessed in an inverted pyramid shape in the scanning range of the electron beam to the sample chamber placed on the stage, and the conductive layer is formed on the first insulating layer in a first internal region which is a bottom surface of the first window portion and is formed on the first outer frame portion in other than the first internal region. ### Claim 4 (depends on 3) The charged particle beam device according to claim 3, wherein the sample chamber includes a second insulating layer provided facing the first insulating layer and forming a holding space for holding the sample, a substrate supporting the second insulating layer, and a reference potential portion provided in contact with the substrate and providing a reference potential, and the sample chamber is placed in a state of being electrically insulated from the stage. ### Claim 5 (depends on 3) The charged particle beam device according to claim 3, wherein the sample chamber includes a second insulating layer provided facing the first insulating layer and forming a holding space for holding the sample, a second outer frame portion supporting the second insulating layer, and a reference potential portion providing a reference potential, in a second internal region which is the bottom surface of a second window portion formed in the second outer frame portion in the same region as the first internal region or a region covering the first internal region when viewed from the upper surface of the sample chamber, the second insulating layer is exposed to the outside atmosphere and the reference potential portion is arranged close to the second internal region, and the sample chamber is placed in a state of being electrically insulated from the stage. ### Claim 6 (depends on 4) The charged particle beam device according to claim 4, wherein the signal detection circuit includes a bias power supply unit that applies a predetermined bias voltage to the conductive layer, and a signal detection unit that outputs a voltage signal which occurs by irradiating the conductive layer with an electron beam and corresponds to the amount of carriers flowing into the bias power supply unit. ### Claim 7 (depends on 6) The charged particle beam device according to claim 6, wherein the bias power supply unit includes a constant voltage source and a voltage follower circuit in which the constant voltage source is connected to a positive input terminal and the conductive layer is connected to a negative input terminal, and the signal detection unit includes a resistor connected between the output terminal of the voltage follower circuit and the conductive layer, and an amplifier that amplifies the potential difference between both ends of the resistor and outputs the amplified potential difference as the voltage signal. ### Claim 8 (depends on 6) The charged particle beam device according to claim 6, wherein the bias power supply unit includes a constant voltage source and a voltage follower circuit in which the constant voltage source is connected to a positive input terminal and the output terminal is connected to a negative input terminal, and the signal detection unit includes a resistor that is connected between the output terminal of the voltage follower circuit and the conductive layer, and an amplifier that amplifies the potential difference between both ends of the resistor and outputs the amplified potential difference as the voltage signal. ### Claim 9 (depends on 6) The charged particle beam device according to claim 6, wherein the bias power supply unit includes a first terminal and a second terminal, and a constant voltage source in which the first terminal is connected to the conductive layer, and the signal detection unit includes a transimpedance amplifier in which a negative input terminal is connected to the second terminal of the constant voltage source. ### Claim 10 (depends on 6) The charged particle beam device according to claim 6, wherein the bias power supply unit includes a first terminal and a second terminal, and a constant voltage source in which the first terminal is connected to the conductive layer, and the signal detection unit includes a resistor that is connected between the second terminal of the constant voltage source and the reference potential portion, and an amplifier that amplifies the potential difference between both ends of the resistor and outputs the amplified potential difference as the voltage signal. ### Claim 11 (depends on 4) The charged particle beam device according to claim 4, wherein the sample chamber is arranged in a vacuum partition that holds the space around the sample at a vacuum degree lower than that of the sample chamber where the stage is arranged, the vacuum partition includes a vacuum partition upper part which is a conductor, a vacuum partition lower part which is an insulator, and a sealing material which is arranged between the vacuum partition upper part and the vacuum partition lower part to make the inside of the vacuum partition airtight, and the vacuum partition upper part is electrically connected to the conductive layer of the sample chamber, and the conductive layer of the sample chamber is irradiated with an electron beam through an opening of the vacuum partition upper part. ### Claim 12 (depends on 5) The charged particle beam device according to claim 5, wherein the sample chamber is arranged in a vacuum partition that holds the space around the sample at a vacuum degree lower than that of the sample chamber where the stage is arranged, the vacuum partition includes a vacuum partition upper part which is a conductor, a vacuum partition lower part which is an insulator, and a sealing material which is arranged between the vacuum partition upper part and the vacuum partition lower part to make the inside of the vacuum partition airtight, and the reference potential portion is fixed to the vacuum partition lower part of the vacuum partition, the vacuum partition upper part is electrically connected to the conductive layer of the sample chamber, and the conductive layer of the sample chamber is irradiated with an electron beam through an opening of the vacuum partition upper part. ### Claim 13 A charged particle beam device comprising: an electron optics system; a stage; a sample chamber holding a sample between a first insulating layer and a second insulating layer facing the first insulating layer, and including a conductive layer formed on the first insulating layer; a first signal detection circuit connected to the conductive layer and detecting a current flowing through the conductive layer; and a second signal detection circuit including a detection electrode providing a reference potential and arranged to face the sample across the second insulating layer, and detecting an electric signal generated in the detection electrode; and a main control unit for controlling the electron optics system and the stage, wherein the main control unit irradiates the conductive layer of the sample chamber placed on the stage with an electron beam from the electron optics system, and is input with a first detection signal from the first signal detection circuit and a second detection signal from the second signal detection circuit. ### Claim 14 (depends on 13) The charged particle beam device according to claim 13, wherein the main control unit converts the first detection signal into first pixel gradation data according to the intensity thereof for each deflection position of the electron beam to the sample chamber and converts the second detection signal into second pixel gradation data according to the intensity thereof. ### Claim 15 (depends on 13) The charged particle beam device according to claim 13, wherein the sample chamber includes a first outer frame portion that supports the first insulating layer and a second outer frame portion that supports the second insulating layer, the first outer frame portion includes a first window portion recessed in an inverted pyramid shape in the scanning range of the electron beam to the sample chamber placed on the stage, the conductive layer is formed on the first insulating layer in a first internal region which is the bottom surface of the first window portion, and is formed on the outer frame portion in other than the first internal region, in a second internal region which is the bottom surface of a second window portion formed on the second outer frame portion in a region that is the same as the first internal region or covers the first internal region when viewed from the upper surface of the sample chamber, the second insulating layer is exposed to the outside atmosphere, and the detection electrode is arranged close to the second internal region. ### Claim 16 (depends on 15) The charged particle beam device according to claim 15, wherein the sample chamber is arranged in a vacuum partition that holds the space around the sample at a vacuum degree lower than that of the sample chamber in which the stage is located, the vacuum partition includes a vacuum partition upper part which is a conductor, a vacuum partition lower part which is an insulator, and a sealing material which is arranged between the vacuum partition upper part and the vacuum partition lower part and makes the inside of the vacuum partition airtight, the detection electrode is fixed to the vacuum partition lower part of the vacuum partition, and the vacuum partition upper part is electrically connected to the conductive layer of the sample chamber, and the conductive layer of the sample chamber is irradiated with an electron beam through an opening of the vacuum partition upper part. ### Claim 17 A charged particle beam device comprising: an electron optics system placed on a column; a stage placed in a sample chamber with a vacuum degree lower than that of the column; a vacuum membrane holder including a membrane including an insulating layer and a conductive layer; a signal detection circuit connected to the conductive layer and detecting a current flowing through the conductive layer; and a main control unit for controlling the electron optics system and the stage, wherein the column and the sample chamber are connected via the vacuum membrane holder, and in the main control unit, a sample placed on the stage is irradiated with an electron beam from the electron optics system through the membrane, and a detection signal from the signal detection circuit is input. ### Claim 18 (depends on 17) The charged particle beam device according to claim 17, wherein the main control unit converts a detection signal from the signal detection circuit into pixel gradation data according to the intensity thereof for each deflection position of an electron beam to the sample. ### Claim 19 (depends on 17) The charged particle beam device according to claim 17, wherein the vacuum membrane holder includes an outer frame portion that supports the insulating layer, the outer frame portion includes a window portion recessed in an inverted pyramid shape in the scanning range of an electron beam, and the conductive layer is formed on the insulating layer in an internal region which is the bottom surface of the window portion and is formed on the outer frame portion in other than the internal region. ### Claim 20 (depends on 17) The charged particle beam apparatus according to claim 17, wherein a potential higher than the potential of the structure of the column is applied to the conductive layer of the vacuum membrane holder. ### Claim 21 An autofocus processing method of a charged particle beam device including an electron optics system, a stage, a main control unit for controlling the electron optics system and the stage, and a computer performing image processing, the method comprising: placing a sample chamber that includes a first insulating layer that is in contact with a sample, an outer frame portion that supports the first insulating layer and includes a window portion recessed in an inverted pyramid shape, and a conductive layer, on the stage, wherein the conductive layer is formed on the first insulating layer in an inner region which is the bottom surface of the window portion, and is formed on the outer frame portion in other than the inner region, connecting a signal detection circuit connected to the conductive layer and detecting a current flowing through the conductive layer, to the main control unit, in the main control unit, scanning an electron beam with respect to a region including the window portion by the electron optics system, and converting a detection signal from the signal detection circuit into first pixel gradation data according to the intensity thereof for each deflection position of the electron beam to the sample chamber, in the computer, performing image processing on the low-magnification image acquired from the first pixel gradation data, and acquiring the position coordinates of a rectangular area including one vertex of the internal region and an inclined surface of the window portion in contact with one vertex of the internal region, in the main control unit, moving the field of view so that the rectangular region becomes the center, scanning an electron beam at a predetermined observation magnification by the electron optics system, and converting a detection signal from the signal detection circuit into second pixel gradation data according to the intensity thereof for each deflection position of the electron beam to the sample chamber, and in the computer, performing image processing on the high-magnification image acquired from the second pixel gradation data, calculating a sharpness evaluation value, and determining the success or failure of autofocus processing based on the sharpness evaluation value. ### Claim 22 (depends on 21) The autofocus processing method according to claim 21, wherein if the sharpness evaluation value calculated by the computer exceeds the threshold value, the main control unit changes the focus condition and the astigmatism correction condition of the electron optics system to move the field of view so that the rectangular region becomes the center, scans an electron beam at a predetermined observation magnification by the electron optics system, and converts a detection signal from the signal detection circuit into second pixel gradation data according to the intensity thereof for each deflection position of the electron beam to the sample chamber. ### Claim 23 A detector comprising: a sample chamber including a holding space for holding a sample, and including a first insulating layer forming the holding space and a conductive layer formed on the first insulating layer; a first signal detection circuit connected to the conductive layer and detecting a current flowing through the conductive layer when the conductive layer is irradiated with an electron beam. ### Claim 24 (depends on 23) The detector according to claim 23, wherein the sample chamber includes a first outer frame portion that supports the first insulating layer, and the first outer frame portion includes a first window portion recessed in an inverted pyramid shape, and the conductive layer is formed on the first insulating layer in a first internal region which is the bottom surface of the first window portion and is formed on the first outer frame portion in other than the first internal region. ### Claim 25 (depends on 24) The detector according to claim 24, wherein the sample chamber includes a second insulating layer provided facing the first insulating layer and forming the holding space, a substrate supporting the second insulating layer, and a reference potential portion provided in contact with the substrate and providing a reference potential. ### Claim 26 (depends on 24) The detector according to claim 24, wherein the sample chamber is provided with a second insulating layer provided facing the first insulating layer and forming the holding space, a second outer frame portion supporting the second insulating layer, and a reference potential portion providing a reference potential, and in a second internal region which is the bottom surface of a second window portion formed in the second outer frame portion in a region that is the same as the first internal region or covers the first internal region when viewed from the upper surface of the sample chamber, the second insulating layer is exposed to the outside atmosphere, and the reference potential portion is arranged close to the second internal region. ### Claim 27 (depends on 24) The detector according to claim 24, wherein the sample chamber includes a second insulating layer provided facing the first insulating layer and forming the holding space, and a second outer frame portion supporting the second insulating layer, a second signal detection circuit, which includes a detection electrode that provides a reference potential and is arranged to face the sample across the second insulating layer, and detects an electric signal generated in the detection electrode, is included, in the second internal region, which is the bottom surface of a second window portion formed on the second outer frame portion in a region that is the same as the first internal region or covers the first internal region when viewed from the upper surface of the sample chamber, the second insulating layer is exposed to the outside atmosphere, and the detection electrode is arranged close to the second internal region. ### Claim 28 A detector comprising: a vacuum membrane holder including a membrane including an insulating layer and a conductive layer; and a signal detection circuit connected to the conductive layer and detecting a current flowing through the conductive layer when the conductive layer is irradiated with an electron beam, wherein the vacuum membrane holder is arranged between a column where an electron optics system for emitting an electron beam is stored and a sample chamber having a vacuum degree lower than that of the column. ### Claim 29 (depends on 28) The detector according to claim 28, wherein the vacuum membrane holder includes an outer frame portion that supports the insulating layer, the outer frame portion includes a window portion recessed in an inverted pyramid shape in the scanning range of the electron beam, and the conductive layer is formed on the insulating layer in an internal region which is the bottom surface of the window portion and is formed on the outer frame portion in other than the internal region.