JP2010107492A - Scanning type device and method for detecting particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scanning type particle detecting device which can scan a sample surface in a short time to detect any particle adhering to the sample surface with a high resolution. <P>SOLUTION: The scanning type particle detecting device uses a probe 8 equipped with a conductor to scan surface of the sample S and then detect a domain to be inspected wherein the particle P adhered to the sample S surface exists. Further, the device includes a probe driving mechanism 6 which relocates the probe 8 to the direction insulating the probe 8 from the sample S surface if any inspection domain is detected, an extraction electrode 11 and acceleration electrode 12 for discharging electrons from the probe 8 as being insulated from the sample S surface, condenser lens coil 13 and objective lens coil 14 to converge the electron discharged from the probe 8 into an electron beam of a cross section smaller than area of the inspection domain and then irradiate the above electron beam on the inspection domain, secondary electron detector 15 for detecting secondary electron discharged from the inspection domain by irradiation with the electron beam, and a controller 18 for generating SEM (Scanning Electron Microscopy) images based on the detection result of the above secondary electron. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a scanning particle detection apparatus and a particle detection method for detecting particles roughly by scanning a probe and finely detecting particles by irradiating an electron beam from the probe.

  When particles peeled off from the inner wall of the semiconductor manufacturing process chamber adhere to the surface of the semiconductor wafer, a short circuit of wiring in the semiconductor device occurs, and the yield of the semiconductor device decreases. For this reason, it is required to inspect the generation state of particles in the semiconductor manufacturing process, for example, the number of particles and the particle diameter. As a method of detecting particles, a light scattering method is used in which particles are irradiated with light and the particles are detected based on scattered light from the particles.

  Semiconductor devices are highly miniaturized, and currently, the processed wiring width has reached less than 50 nm. In the near future, 30 nm wiring processing technology is being put into practical use. However, a light scattering technique that can detect particles of 50 nm or less does not yet exist. For this reason, the relationship between the yield and the particles cannot be discussed, and the yield of the semiconductor device may be reduced.

  On the other hand, as a device capable of detecting particles of 50 nm or less, a sample was scanned by generating a microwave near field at the tip of the probe and detecting an interaction with the sample, thereby adhering to the sample. A scanning near-field microwave microscope for detecting particles has been proposed (for example, Patent Document 1).

  In addition, a scanning electron microscope (SEM) that can detect particles of 50 nm or less attached to a sample by irradiating the sample with an electron beam and detecting secondary electrons emitted from the sample has been put into practical use. Yes.

JP 2002-189043 A

  However, in the scanning near-field microwave microscope, it is possible to detect an inspection target area where particles adhering to the sample exist, but information such as the particle diameter and the number of particles existing in the inspection target area is obtained. There was a problem that could not be obtained.

  Further, in SEM, it is possible to image particles adhering to a sample and measure the particle diameter, but there is a problem that it takes time to scan the entire surface of the sample.

  The present invention has been made in view of such circumstances, and provides a scanning particle detection apparatus and particle detection method capable of scanning a sample surface in a short time and detecting particles adhering to the sample surface with high resolution. The purpose is to provide.

  Another object of the present invention is to obtain information on the number of particles attached to the sample surface and the particle diameter by detecting an inspection target region where particles are present by scanning a probe and generating an image of the inspection target region. An object of the present invention is to provide a scanning particle detection apparatus capable of

  Another object of the present invention is to provide a scanning particle detection apparatus capable of analyzing the composition of particles adhering to a sample surface by detecting Auger electrons.

  Another object of the present invention is to provide a scanning particle detector capable of analyzing the composition of particles adhering to a sample surface by detecting characteristic X-rays.

  The scanning particle detection apparatus according to the present invention is a scanning particle detection apparatus that scans the surface of a sample with a probe having a conductor and detects an inspection object region where particles attached to the sample surface exist. When detecting a region, probe driving means for moving the probe in a direction away from the sample surface, and electron emission for emitting electrons from the probe in a state where the probe is separated from the sample surface Means for focusing the electrons emitted from the probe into an electron beam having a cross-sectional area smaller than the area of the inspection target region, and irradiating the electron beam on the inspection target region; And a secondary particle detecting means for detecting secondary particles emitted from the target region.

  The scanning particle detection apparatus according to the present invention is characterized in that the inspection target region is scanned with the electron beam to detect particles adhering to the inspection target region on the sample surface.

  In the scanning particle detection apparatus according to the present invention, the probe includes a transmission line that transmits a microwave from a proximal end side to a distal end side facing the sample surface, and further transmits the microwave from the proximal end side. A microwave generator to be supplied to a line; a resonator connected to the base end side of the transmission line; and a microwave that resonates the microwave; a microwave detection unit that detects the microwave resonated by the resonator; And a means for detecting a region to be inspected based on the frequency of the microwave detected by the microwave detection unit.

  The scanning particle detection apparatus according to the present invention is characterized in that the electron emission means includes an extraction electrode for extracting electrons from the probe and an acceleration electrode for accelerating the electrons extracted from the probe.

  In the scanning particle detector according to the present invention, when the electron beam is irradiated on the sample surface, the extraction electrode and the acceleration electrode are advanced between the probe and the sample surface, and the particle is detected by scanning the probe. In this case, an electrode driving means for retracting the extraction electrode and the acceleration electrode is provided.

  In the scanning particle detector according to the present invention, the secondary particle detector includes a secondary electron detector that detects the amount of secondary electrons emitted from the inspection target region by irradiation with an electron beam, An image generating means for generating an image of particles adhering to the inspection target region on the sample surface based on the amount of secondary electron emission detected by the secondary electron detection unit is provided.

  In the scanning particle detection apparatus according to the present invention, the secondary particle detection unit includes an Auger detection unit that detects energy of Auger electrons emitted from the inspection target region by irradiation with an electron beam, and further includes a plurality of elements and Based on the Auger electron energy table in which the energy of the Auger electrons inherent to the element is associated, the energy of Auger electrons detected by the Auger detection unit, and the table, the composition of particles attached to the sample surface is determined. And means for analyzing.

  In the scanning particle detection apparatus according to the present invention, the secondary particle detection unit includes a characteristic X-ray detection unit that detects energy of characteristic X-rays radiated from the inspection target region by irradiation with an electron beam, and further includes a plurality of characteristic X-ray detection units. And the characteristic X-ray energy table in which the characteristic X-ray energy inherent to the element is associated, the characteristic X-ray energy detected by the characteristic X-ray detector and the table, and the sample And a means for analyzing the composition of particles adhered to the surface.

  In the particle detection method according to the present invention, the inspection target region is detected in the particle detection method in which the surface of the sample is scanned with a probe having a conductor portion, and the inspection target region where particles attached to the sample surface are present is detected. In this case, the probe is moved in a direction away from the sample surface, the electrons are emitted from the probe in a state where the probe is separated from the sample surface, and the electrons emitted from the probe are inspected. Focusing on an electron beam having a cross-sectional area smaller than the area of the target region, irradiating the target region with the electron beam, and detecting secondary particles emitted from the target region by irradiation of the electron beam. It is characterized by.

In the present invention, the sample surface is scanned with a probe to detect an inspection target area where particles adhering to the sample surface are present. Since the inspection target region is roughly detected, it is possible to scan the sample surface in a shorter time than when the sample surface is scanned with an electron beam described later.
When the inspection target area is detected, the probe is separated from the sample surface. Then, electrons are emitted from the probe, focused on an electron beam having a cross-sectional area smaller than the area of the inspection target region, and irradiated with the electron beam. Next, the particles are finely detected by the secondary particles released from the sample surface. Since the configuration is such that particles are detected by an electron beam having a smaller cross-sectional area than the area of the inspection target region, it is possible to obtain detailed information about the particles compared to the case where the particles are detected only by scanning with a probe. Become.
In addition, it is not necessary to move and align the sample, which is necessary when the coarse detection and fine detection of the particles are performed by separate apparatuses, and the particles attached to the sample can be efficiently detected.

  In the present invention, by scanning the coarsely detected inspection target region with an electron beam, detailed information on the particles existing in the inspection target region can be obtained as compared with the case of detecting particles only by scanning with the probe. It becomes possible to obtain.

  In the present invention, microwaves are supplied from the base end side of the transmission line of the probe, and a microwave near field is generated on the tip end side of the probe. A resonator is connected to the tip side of the probe, and a microwave resonated by the resonator is detected by a microwave detection unit. Since the frequency of the resonating microwave fluctuates due to the interaction between the probe and the sample, it is possible to detect the inspection target region where the particles attached to the sample exist based on the frequency.

  In the present invention, the extraction electrode extracts electrons from the conductor portion of the probe by an electric field, and the acceleration electrode is extracted to accelerate the electrons. The accelerated electrons are focused as an electron beam by an electron lens and irradiated onto the sample surface.

  In the present invention, when particles are detected by an electron beam, an extraction electrode and an acceleration electrode necessary for generating the electron beam are advanced between the probe and the sample surface. When particles are detected by scanning with a probe, it is possible to retract the extraction electrode and the acceleration electrode to avoid unnecessary interference.

  In the present invention, the amount of secondary electrons emitted from the region to be inspected by the electron beam irradiation is detected by the secondary electron detector, and the image generating means An image of particles attached to the particle is generated.

  In the present invention, the Auger detector detects the energy of Auger electrons emitted from the region to be inspected by the electron beam irradiation. Based on the detected Auger electron energy and the Auger electron energy table, the composition of particles adhering to the inspection target region is analyzed.

  In the present invention, the characteristic X-ray detection unit detects the energy of the characteristic X-rays emitted from the inspection target region by the electron beam irradiation. Based on the detected characteristic X-ray energy and the characteristic X-ray energy table, the composition of the particles adhering to the inspection target region is analyzed.

  According to the present invention, it is possible to scan the sample surface in a short time and detect particles adhering to the sample surface with high resolution.

  Further, by detecting an inspection target region where particles exist by scanning the probe and generating an image of the inspection target region, information on the number of particles attached to the sample surface and the particle diameter can be obtained.

  Furthermore, by detecting Auger electrons, the composition of particles attached to the sample surface can be analyzed.

  Furthermore, the composition of particles adhering to the sample surface can be analyzed by detecting characteristic X-rays.

It is a sectional side view which shows typically the structure of the scanning particle | grain detection apparatus which concerns on embodiment of this invention. It is a sectional side view which shows typically the structure of the scanning particle | grain detection apparatus which concerns on embodiment of this invention. It is a flowchart which shows the process sequence of the control part which concerns on particle | grain detection. It is a flowchart which shows the process sequence of the control part which concerns on particle | grain detection. 10 is a flowchart showing a processing procedure of a control unit related to particle detection in Modification 1; 10 is a flowchart showing a processing procedure of a control unit related to particle detection in Modification 1; FIG. 10 is a side sectional view schematically showing a configuration of a scanning particle detection device according to Modification 2. 10 is a flowchart showing a processing procedure of a control unit related to particle detection in Modification 2. It is a sectional side view which shows typically the structure of the scanning particle | grain detection apparatus concerning the modification 3. 10 is a flowchart showing a processing procedure of a control unit related to particle detection in Modification 3. It is a sectional side view which shows typically the structure of the scanning particle | grain detection apparatus which concerns on the modification 4. It is a sectional side view which shows typically the structure of the scanning particle | grain detection apparatus which concerns on the modification 4. FIG. 10 is a side sectional view schematically showing a configuration of a scanning particle detection device according to Modification 5. FIG. 10 is a side sectional view schematically showing the configuration of a scanning particle detection device according to Modification 6.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
1 and 2 are side cross-sectional views schematically showing the configuration of a scanning particle detection apparatus according to an embodiment of the present invention. The scanning particle detector according to the present embodiment combines the functions of a scanning near-field microwave microscope and SEM to efficiently detect particles P adhering to a sample S such as a wafer, and the number of particles and the particle diameter. It is possible to measure. In the figure, reference numeral 1 denotes a vacuum chamber. The vacuum chamber 1 is provided on a bottomed cylindrical first vacuum chamber 1a and the top side of the first vacuum chamber 1a, and has a shorter diameter than the first vacuum chamber 1a. And a second vacuum chamber 1b having a cylindrical shape.

  The first vacuum chamber 1a includes a bottom plate portion to be provided horizontally, a peripheral wall portion provided around the bottom plate portion, and an annular plate-shaped top portion, and a movable stage 16 is provided on the bottom plate portion. . The movable stage 16 has a disk-like stage portion on which a sample S, for example, a wafer on which particles P adhere, and a coarse movement of the stage portion in two directions substantially parallel to and substantially perpendicular to the bottom plate portion. And a stage drive unit for fine movement, for example, a stepping motor for coarse movement and a piezo element for fine movement. In the following description, assuming that the bottom plate portion is installed horizontally, the two directions will be described as the X direction and the Y direction, which are horizontal directions, and the substantially vertical direction as a vertical direction.

  Moreover, the vacuum pump 17 is connected to the appropriate location of the surrounding wall part of the 1st vacuum chamber 1a. The vacuum pump 17 is composed of, for example, a primary pump such as a rotary pump and a secondary pump such as a turbo molecular pump.

  The second vacuum chamber 1b includes a peripheral wall portion extending vertically upward from an inner peripheral edge portion of the top portion constituting the first vacuum chamber 1a, and an annular top portion. A probe driving mechanism 6 for moving a probe 8 provided in a resonator 5 (described later) in the direction of contact with or away from the sample S, that is, in the vertical direction, is provided at an appropriate location outside the peripheral wall portion or the top portion. Is provided. The probe driving mechanism 6 includes, for example, a stepping motor for coarsely moving the probe 8 in the contact / separation direction and a piezo element for fine movement in the contact / separation direction.

  The resonator 5 is configured to move in the contact / separation direction on the central axis of the second vacuum chamber 1b by the probe driving mechanism 6. The resonator 5 has a cylindrical shape so as to resonate the microwave for detecting the particles P adhering to the sample S, and a hole for inputting / outputting the microwave is formed in the substantially central portion of the bottom and the top. ing. A three-terminal circulator 3 is disposed on the top side of the resonator 5, and a probe 8 is connected to the bottom.

  The circulator 3 includes first to third terminals 3 a, 3 b, and 3 c, and the first terminal 3 a generates a high frequency in the GHz band, that is, a microwave, and outputs the microwave to the resonator 5. A wave generator 2 is connected. The second terminal 3c of the circulator 3 is connected to the hole in the top of the resonator 5, and the third terminal 3b detects the microwave resonated by the resonator 5 and outputs the detection result. A microwave detection unit 4, for example, a diode detector is connected.

  The probe 8 is suspended from a hole at the bottom of the resonator 5 and is arranged on the vacuum chamber 1 side via a vacuum bellows 7 provided at the top of the second vacuum chamber 1b. The probe 8 has a microwave transmission line 8a that transmits microwaves from the proximal end portion on the resonance portion side to the distal end portion facing the sample S. The microwave transmission line 8a is made of a dielectric material, such as quartz, and has an elongated rod shape having a taper at the tip. Further, the peripheral surface of the microwave transmission path, at least two side surfaces sandwiching the microwave transmission line, is covered with a conductive portion 86. Further, the tip of the probe 8 is formed to be smaller than the wavelength of the microwave so as to generate a near-field of the microwave. For example, when the region to be inspected in which the 50 nm particle P attached to the sample S is roughly detected, the tip portion is formed to have a radius of curvature of about 1 μm in order to achieve a resolution of several hundred nm to 1 μm. good.

  Further, a hole is formed in the lower part of the peripheral wall of the second vacuum chamber 1b, and an extraction electrode 11 for extracting electrons from the probe 8 and an acceleration electrode 12 for accelerating the electrons extracted by the extraction electrode 11 are provided. It protrudes from the hole so as to be able to advance and retreat. The extraction electrode 11 and the acceleration electrode 12 are connected to the electrode driving unit 10 provided outside the second vacuum chamber 1b via the vacuum bellows 9, and the electrode driving unit 10 connects the extraction electrode 11 and the acceleration electrode 12 to each other. A motor is provided to advance and retract between the probe 8 and the surface of the sample S. Further, the scanning particle detection apparatus applies a voltage of several kV between the extraction electrode 11 and the acceleration electrode 12 and the probe 8, thereby supplying a power source 30 for extracting and accelerating electrons from the probe 8. Prepare.

  Furthermore, a condenser lens coil 13 (electron lens) for focusing electrons emitted from the probe 8 and generating an electron beam is vertically below the advanced extraction electrode 11 and acceleration electrode 12, and a focused electron beam. An objective lens coil 14 (electron lens) for irradiating the surface of the sample S is arranged. In addition, a secondary electron detector 15 that detects secondary electrons emitted from the sample S irradiated with the electron beam and outputs a detection result is disposed at an appropriate location in the second vacuum chamber 1b.

  Further, the scanning particle detection apparatus includes a control unit 18 that controls the entire apparatus. The control unit 18 is, for example, a microcomputer including a CPU, a RAM, a timer, an I / O port, and the like. The microwave generator 2, the probe driving mechanism 6, the movable stage 16, the microwave detection unit 4, the secondary electron detection unit 15 and the like are connected to the I / O port, and the control unit 18 controls each part. By giving signals, the operation of the microwave generator 2, the probe driving mechanism 6 and the movable stage 16 is controlled, and the detection signals output from the microwave detection unit 4 and the secondary electron detection unit 15 are input. It is configured as follows. The control unit 18 is provided with a storage unit 19, a display unit 20, and an operation unit 21. The storage unit 19 is a hard disk, a semiconductor memory, or the like that stores a computer program for controlling the operation of each component unit. The display unit 20 displays an image based on image data provided from the control unit 18. CRT, liquid crystal display. The operation unit 21 includes a keyboard, a mouse, and the like that give an operation signal corresponding to the operation content of the user to the control unit 18.

  3 and 4 are flowcharts showing a processing procedure of the control unit 18 related to particle detection. When receiving a particle detection start instruction, the control unit 18 first moves the movable stage 16 to a predetermined position (step S11). And the control part 18 gives a control signal to the electrode drive part 10, and moves the extraction electrode 11 and the acceleration electrode 12 to a backward direction, as shown in FIG. 2 (step S12). Next, the control unit 18 gives a control signal to the microwave generator 2 to generate a microwave (step S13). Then, the control unit 18 moves the probe 8 in the proximity direction, that is, vertically downward (step S14).

  Next, the control unit 18 monitors the resonance frequency of the microwave detected by the microwave detection unit 4 to determine whether the distance between the probe 8 and the sample S is less than a predetermined distance, for example, less than 100 nm. Determination is made (step S15). When it determines with it not being less than predetermined distance (step S15: NO), the control part 18 returns a process to step S14, and continues the movement of the probe 8. FIG. When it determines with it being less than predetermined distance (step S15: YES), the control part 18 detects the resonant frequency of a microwave in the microwave detection part 4 (step S16). Then, a change in the resonance frequency accompanying the scanning of the sample S is calculated (step S17). Next, the control unit 18 determines whether or not the particles P are present in the inspection target region of the sample S to which the probe 8 is close based on the change in the resonance frequency (step S18).

Note that the rate of change of the resonant frequency of the microwave is expressed by the following equation. Where F is the resonance frequency, ε ₀ is the vacuum dielectric constant, μ ₀ is the vacuum magnetic permeability, Z ₀ is the impedance characteristic of the microwave transmission line 8a, L is the length of the resonance part in the transmission direction, and ε _eff is The dielectric constant of the microwave transmission line 8a, ΔCt, is the rate of change of capacitance at the tip of the probe 8.
ΔF / F = −Z ₀ / L (ε ₀ μ ₀ ε _eff ) ^1/2 ΔCt (1)

  When it is determined that the particles P are not present (step S18: NO), the control unit 18 gives a control signal to the movable stage 16 and causes the probe 8 to scan the surface of the sample S by roughly driving the movable stage 16. (Step S19), the process returns to Step S16.

  When it determines with the particle | grains P existing (step S18: YES), the control part 18 gives a control signal to the microwave generator 2, and stops the microwave generator 2 (step S20).

  Next, the control unit 18 gives the control unit 18 to the probe driving mechanism 6 and moves the probe 8 in the separation direction (step S21). And the control part 18 gives a control signal to the electrode drive part 10, and moves the extraction electrode 11 and the acceleration electrode 12 to an advance direction (step S22).

  And the control part 18 applies a voltage to the extraction electrode 11, the acceleration electrode 12, the condenser lens coil 13, and the objective lens coil 14 (step S23). Next, the control unit 18 finely drives the movable stage 16 to scan the region to be inspected with the electron beam, and the secondary electron detection unit 15 detects the amount of secondary electrons emitted (step S24).

  And the control part 18 produces | generates the SEM image of the sample S to which the particle P adhered based on the detection result of step S24 (step S25). Next, the control unit 18 determines whether or not the scanning is finished (step S26). When it is determined that the scanning is not finished (step S26: NO), the control unit 18 gives a control signal to the movable stage 16, roughly drives the movable stage 16 (step S27), and returns the process to step S12. When it determines with complete | finishing scanning (step S26: YES), the control part 18 performs the stop process which stops operation | movement of each structure part (step S28), and complete | finishes a process.

In the scanning particle detection apparatus and particle detection method configured as described above, the near-field of the microwave is generated at the tip of the probe 8 to scan the surface of the sample S, thereby attaching to the surface of the sample S. The particles P can be roughly detected in a short time. Further, by scanning the inspection target region roughly detected with an electron beam, the particles P can be detected finely and detailed information on the particles P can be obtained.
Specifically, by generating an SEM image of the inspection target region, information such as the number of particles P and the particle diameter of the particles P existing in the inspection target region can be obtained.
In this way, it becomes possible to detect particles P of 50 nm or less, which has conventionally been impossible, and early development of a next-generation low-dust semiconductor manufacturing apparatus can be achieved. In addition, in the semiconductor device factory, it is possible to quickly improve the yield of next-generation devices.

  Further, by forming a tip portion having a radius of curvature of about 1 μm on the probe 8 and generating a near-field of microwaves at the tip portion, a region to be inspected in which particles P adhering to the surface of the sample S are present. Can be detected roughly.

  Further, when the inspection target area is detected, the probe 8 is moved vertically upward as it is, and the probe 8 is used to irradiate the electron beam. Therefore, the coarse detection and the fine detection are separated from each other. It is possible to save the trouble of aligning the SEM observation area, which is necessary when the apparatus is used.

  Furthermore, when the surface of the sample S is scanned with the probe 8 using a near field, the extraction electrode 11 and the acceleration electrode 12 are configured to be retracted. The effect can be reduced.

  In the embodiment, the configuration is such that the particles P adhering to the surface of the sample S are roughly detected using a near-field of microwaves. However, the particle detection method is based on rough detection of the particles P, that is, irradiation with an electron beam. In contrast, any other configuration may be employed as long as the method can scan the surface of the sample S in a short time and detect the region where the particles P are present. For example, the particle P may be roughly detected by detecting the near field related to electromagnetic waves other than microwaves, the atomic force between the probe 8 and the sample S, the electric force, the magnetic force, and other various interactions.

  The particles P are finely detected using secondary electrons emitted from the surface of the sample S by irradiation of the electron beam, but other secondary particles, for example, if detailed information on the particles P can be obtained, for example Further, photons such as characteristic X-rays and ultraviolet rays, Auger electrons, counter electrons, secondary ions, and the like may be detected.

  Furthermore, the scanning particle detection apparatus and the particle detection method according to the present embodiment may be applied not only to offline measurement but also to in-line measurement, online measurement, or in-situ measurement.

  Furthermore, the scope of application of the scanning particle detection apparatus and particle detection method according to the present embodiment is not particularly limited. For example, the processing level of a semiconductor, the purpose of quality inspection for inspecting quality, the purpose of analysis of defects and defects, You may apply to the apparatus and process used for various objectives, such as the research and development objective of a new semiconductor circuit.

(Modification 1)
In the scanning particle detection apparatus and the particle detection method according to the first modification, a plurality of inspection target areas in which particles P adhere to the surface of the sample S are first roughly detected. Is different from the above-described embodiment. Below, the said difference is mainly demonstrated.
5 and 6 are flowcharts showing the processing procedure of the control unit 18 related to particle detection in the first modification. As in steps S11 to S17, the control unit 18 brings the probe 8 close to the surface of the sample S, and executes processing for detecting the resonance frequency of the microwave and calculating a change in the resonance frequency in steps S31 to S37.

  When the process of step S37 is completed, the control unit 18 determines whether or not the particle P is present in the inspection target region of the sample S in which the probe 8 is close based on the change in the resonance frequency (step). S38). When it determines with the particle | grains P existing (step S38: YES), the control part 18 memorize | stores the position coordinate of a test object area | region (step S39).

  When it is determined that the particle P does not exist (step S38: NO), or when the process of step S39 is completed, it is determined whether the scanning of the surface of the sample S is completed (step S40). When it is determined that the scanning is not finished (step S40: NO), the control unit 18 gives a control signal to the movable stage 16 and roughly drives the movable stage 16, thereby scanning the surface of the sample S with the probe 8. (Step S41), and the process returns to Step S36.

  If it is determined that the surface of the sample S has been scanned (step S40: YES), the control unit 18 gives a control signal to the microwave generator 2 and stops the microwave generator 2 (step S42).

  Next, the control unit 18 determines whether or not the inspection target area position coordinates are stored (step S43). When it determines with not having memorize | stored inspection object area | region position coordinates (step S43: NO), the control part 18 finishes a process.

  When it is determined that the inspection target region position coordinates are stored (step S43: YES), the control unit 18 reads the inspection target region position coordinates from the storage unit 19 (step S44), and based on the inspection target region position coordinates. The movable stage 16 is moved to the inspection target area position (step S45).

  And the control part 18 performs the process which concerns on the production | generation of a SEM image by step S46-50 like step S21-25.

  When the process of step S50 is completed, the control unit 18 determines whether or not there is an undetected particle P by SEM (step S51). When it determines with there existing undetected particle P (step S51: YES), the control part 18 returns a process to step S44. When it determines with there being no undetected particle P (step S51: NO), the control part 18 performs the stop process which stops operation | movement of each structure part (step S52), and complete | finishes a process.

  In the scanning particle detection apparatus and the particle detection method according to the first modification, a plurality of inspection target areas are first roughly detected, and then an SEM image of each inspection target area is generated. Further, the number of times the probe 8, the extraction electrode 11 and the acceleration electrode 12 are driven can be reduced, and the detection of the particle P and the measurement of the particle diameter can be performed more efficiently.

(Modification 2)
The scanning particle detection apparatus according to the modified example 2 is different from the above-described embodiment in that it is configured to detect the composition of the particles P by detecting Auger electrons in addition to the detection of the particles P. Below, the said difference is mainly demonstrated.
FIG. 7 is a side sectional view schematically showing the configuration of the scanning particle detection apparatus according to the second modification. The scanning particle detection apparatus according to the modification 2 includes an Auger detection unit that detects energy of Auger electrons emitted from the sample S at an appropriate position of the first vacuum chamber 1a. The storage unit 19 also stores an Auger electron energy table 219a in which a plurality of elements and energy of Auger electrons emitted when the elements are irradiated with an electron beam are associated with each other. The energy of Auger electrons is unique to the element.

FIG. 8 is a flowchart illustrating a processing procedure of the control unit 18 related to particle detection in the second modification. The control unit 18 further executes the following process between the process of step S25 and the process of step S26.
The control unit 18 detects the energy of Auger electrons at the Auger electron detection unit 222 (step S251). Then, the control unit 18 reads the Auger electron energy table 219a from the storage unit 19 (Step S252), and performs composition analysis of the particles P based on the Auger electron energy detected in Step S251 and the Auger electron energy table 219a. This is performed (step S253).

  In the scanning particle detection device and the particle detection method according to Modification 2, the composition of the particles P attached to the surface of the sample S can be specified by detecting Auger electrons.

(Modification 3)
The scanning particle detection apparatus according to the modified example 3 is different from the above-described embodiment in that it is configured to detect the composition of the particles P by detecting characteristic X-rays in addition to the detection of the particles P. Below, the said difference is mainly demonstrated.
FIG. 9 is a side sectional view schematically showing the configuration of the scanning particle detection apparatus according to the third modification. The scanning particle detection apparatus according to Modification 3 includes a characteristic X-ray detection unit 322 that detects energy of characteristic X-rays emitted from the sample S at an appropriate location in the first vacuum chamber 1a. In addition, the storage unit 19 stores a characteristic X-ray energy table 319a in which a plurality of elements are associated with energy of characteristic X-rays emitted when the elements are irradiated with an electron beam. The energy of the characteristic X-ray is unique to the element.

FIG. 10 is a flowchart illustrating a processing procedure of the control unit 18 relating to particle detection in the third modification. The control unit 18 further executes the following process between the process of step S25 and the process of step S26.
The control unit 18 detects the characteristic X-ray energy by the characteristic X-ray detection unit 322 (step S351). Then, the control unit 18 reads the characteristic X-ray energy table 319a from the storage unit 19 (step S352), and based on the characteristic X-ray energy detected in step S351 and the characteristic X-ray energy table 319a, A composition analysis is performed (step S353).

  In the scanning particle detection apparatus and particle detection method according to Modification 3, the composition of the particles P attached to the surface of the sample S can be specified by detecting the energy of characteristic X-rays.

(Modification 4)
Since the configuration of the probe 408 constituting the scanning particle detection device according to the embodiment is different from that of the above-described embodiment, the scanning particle detection device according to the modification 4 mainly focuses on the above differences. explain. The scanning particle detection apparatus according to the modified example 4 combines the functions of a scanning microscope using a mechanical probe and SEM, and efficiently detects particles P adhering to a sample S such as a wafer. It is possible to measure.

  11 and 12 are side cross-sectional views schematically showing the configuration of the scanning particle detector according to Modification 4. The probe 408 is suspended in a hole at the bottom of the resonator 5 and is disposed on the vacuum chamber 1 side via a vacuum bellows 7 provided at the top of the second vacuum chamber 1b. The probe 408 includes a rod-like stainless steel lead electrode 408a connected to the resonator 5, and a tungsten chip 408b provided at the tip of the lead electrode 408a. The probe 408, together with the extraction electrode 11 and the acceleration electrode 12, constitutes a field emission electron type electron gun.

  The lead electrode 408a serves as both means for applying a voltage to the tungsten chip 408b and means for applying the high frequency generated by the microwave generator 2 to the tungsten chip 408b. The lead electrode 408a is connected to the power supply 30, and is configured such that a voltage of several kV is applied between the lead electrode 11 and the acceleration electrode 12 and the lead electrode 408a.

The tip of the tungsten chip 408b is formed with a thickness of about 100 nm and serves as both an SEM chip and a mechanical probe. When a voltage is applied between the tungsten chip 408b and the extraction electrode 11 through the lead electrode 408a, electrons are extracted from the tungsten chip 408b, and the electrons extracted by the extraction electrode 11 are accelerated by the acceleration electrode 12, It becomes an electron beam for scanning the sample S. On the other hand, the high frequency applied to the tungsten chip 408 b varies in response due to the interaction with the surface of the sample S, and the response variation is detected by the microwave detection unit 4.
In the fourth modification, the same operational effects as in the embodiment are obtained.

(Modifications 5 and 6)
The scanning particle detection device according to the modification 5 is different from the above-described embodiment in the configuration of the probe 408 constituting the scanning particle detection device according to the modification 2. Similarly, the scanning particle detection device according to the modification 5 is different from the above-described embodiment in the configuration of the probe 408 constituting the scanning particle detection device according to the modification 3.
FIG. 13 is a side cross-sectional view schematically showing the configuration of the scanning particle detection apparatus according to Modification Example 5. FIG. 14 is a side cross-sectional view schematically showing the configuration of the scanning particle detection apparatus according to Modification Example 6. is there. The configuration and operation of the probe 408 are the same as those of the scanning particle detector according to the fourth modification.

In the modified examples 5 and 6, the same effects as the modified examples 2 and 3 are obtained.

  It should be understood that the embodiment disclosed this time is illustrative in all respects and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Microwave generator 3 Circulator 4 Microwave detection part 5 Resonator 6 Probe drive mechanism 7 Vacuum bellows 8,408 Probe 8a Microwave transmission line 8b Conductor part 10 Electrode drive part 11 Extraction electrode 12 Acceleration electrode 13 Condenser lens coil 14 Objective lens coil 15 Secondary electron detection unit 16 Movable stage 18 Control unit 19 Storage unit 20 Display unit 21 Operation unit 222 Auger electron detection unit 219a Auger electron energy table 322 Characteristic X-ray detection unit 319a Characteristic X-ray energy table 408a Lead electrode 408b Tungsten tip S Sample P Particle

Claims (9)

In a scanning particle detector that scans the surface of a sample with a probe having a conductor portion and detects an inspection target area where particles attached to the surface of the sample are present,
When detecting a region to be inspected, probe driving means for moving the probe in a direction away from the sample surface;
Electron emitting means for emitting electrons from the probe in a state where the probe is separated from the sample surface;
An electron lens that focuses the electrons emitted from the probe into an electron beam having a cross-sectional area smaller than the area of the inspection target region, and irradiates the inspection target region with the electron beam;
And a secondary particle detecting means for detecting secondary particles emitted from the region to be inspected by irradiation with an electron beam. The scanning particle detection apparatus according to claim 1, wherein the inspection target region is scanned with the electron beam to detect particles adhering to the inspection target region on the sample surface. The probe is
A transmission line for transmitting microwaves from the proximal end side to the distal end side facing the sample surface,
Furthermore, a microwave generator for supplying microwaves from the base end side to the transmission line;
Connected to the base end side of the transmission line, and a resonator for resonating microwaves;
A microwave detection unit for detecting a microwave resonated by the resonator;
The scanning particle detection apparatus according to claim 1, further comprising: means for detecting an inspection target region based on a frequency of the microwave detected by the microwave detection unit. The electron emission means includes
An extraction electrode for extracting electrons from the probe;
The scanning particle detection apparatus according to claim 1, further comprising: an acceleration electrode that accelerates electrons extracted from the probe. When the sample surface is irradiated with the electron beam, the extraction electrode and the acceleration electrode are advanced between the probe and the sample surface, and when particles are detected by scanning the probe, the extraction electrode and the acceleration electrode are moved backward. The scanning particle detection apparatus according to claim 4, further comprising an electrode driving unit for causing the scanning particle detection apparatus to operate. The secondary particle detecting means includes
A secondary electron detector that detects the amount of secondary electrons emitted from the inspection target region by irradiation with an electron beam,
The image processing device further comprises image generation means for generating an image of particles adhering to the region to be inspected on the sample surface based on the amount of secondary electrons emitted detected by the secondary electron detector. The scanning particle detector according to any one of claims 1 to 5. The secondary particle detecting means includes
An Auger detector that detects the energy of Auger electrons emitted from the region to be inspected by electron beam irradiation,
Furthermore, an Auger electron energy table that associates the energy of the Auger electrons inherent to a plurality of elements and the elements;
A means for analyzing the composition of particles adhering to the sample surface based on the energy of Auger electrons detected by the Auger detection unit and the table is provided. The scanning particle detector according to claim 1. The secondary particle detecting means includes
A characteristic X-ray detector that detects the energy of characteristic X-rays emitted from the region to be inspected by electron beam irradiation;
Furthermore, a characteristic X-ray energy table in which a plurality of elements and energy of the characteristic X-rays inherent to the elements are associated,
A means for analyzing the composition of particles adhering to the sample surface based on the energy of the characteristic X-ray detected by the characteristic X-ray detection unit and the table. 8. The scanning particle detector according to any one of 7 above. In the particle detection method of scanning the sample surface with a probe having a conductor part and detecting an inspection target region where particles attached to the sample surface exist,
When detecting the region to be inspected, move the probe in a direction away from the sample surface,
In a state where the probe is separated from the sample surface, electrons are emitted from the probe,
Focusing electrons emitted from the probe into an electron beam having a cross-sectional area smaller than the area of the inspection target region, irradiating the inspection target region with the electron beam,
A particle detection method comprising: detecting secondary particles emitted from a region to be inspected by irradiation with an electron beam.

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