Inspection device and inspection element

Abstract

The present invention improves the performance of an inspection device. Provided is, for example, an inspection device 100 comprising an electron detection element 30 and an X-ray detection element 40, wherein: the electron detection element 30 is disposed between a sample stage 14 on which a sample 20 can be placed and an electron source 10; the X-ray detection element 40 is disposed between the electron detection element 30 and the electron source 10; and the electron detection element 30 and the X-ray detection element 40 are disposed so as to overlap in a plan view.

Description

Technical Field

[0001] The present invention relates to an inspection apparatus, inspection elements, and inspection techniques, and more particularly to a technique effective when applied to an inspection apparatus, inspection elements, and inspection method used for inspecting semiconductor devices, for example.

Background Art

[0002] Japanese Patent No. 6416199 (Patent Document 1) describes a technique related to a detector and an electron detection device capable of detecting X-rays and electrons.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As an inspection process for semiconductor devices, there is a process of inspecting etching defects in deep holes (for example, contact holes and via holes) formed in semiconductor devices. In this inspection process, for example, an inspection apparatus (scanning electron microscope) that inspects etching defects in deep holes by irradiating primary electrons generated by an electron source onto the deep holes and detecting secondary electrons and reflected electrons emitted from the deep holes is used. In this specification, when there is no particular need to distinguish between secondary electrons and reflected electrons, they will simply be referred to as electrons.

[0005] In this regard, in recent years, with the high integration and miniaturization of semiconductor devices, the aspect ratio of deep holes has been increasing. When the aspect ratio of the deep holes becomes high in this way, the probability that electrons generated from the bottom of the deep holes are absorbed by the side walls of the deep holes increases. As a result, a situation has occurred in which it is difficult to obtain information on the bottom of the deep holes. This means that it has become difficult to detect etching defects in deep holes, and improvement is needed.

[0006] Therefore, attempts have been made to obtain information at the bottom of a deep hole by using X-rays with high transmittance. Specifically, it has been considered to provide an inspection apparatus with an electron detection element for detecting electrons and an X-ray detection element for detecting X-rays. However, in the technology under consideration, a configuration is considered in which the electron detection element and the X-ray detection element are not arranged overlappingly.

[0007] However, in the case of an inspection apparatus having such a configuration, the solid angle at which electrons are incident on the electron detection element from the deep hole and the solid angle at which X-rays are incident on the X-ray detection element from the deep hole become small. This means that electrons cannot be detected efficiently by the electron detection element and X-rays cannot be detected efficiently by the X-ray detection element.

[0008] Therefore, in the technology of providing an inspection apparatus with an electron detection element for detecting electrons and an X-ray detection element for detecting X-rays, it is desired to develop an inspection apparatus capable of inspecting etching defects of deep holes with a high aspect ratio with high precision. That is, in an inspection apparatus including an electron detection element and an X-ray detection element, a device for inspecting etching defects of deep holes with a high aspect ratio with high precision is desired.

Means for Solving the Problem

[0009] An inspection apparatus according to an embodiment includes an electron source that generates primary electrons and irradiates a sample, an electron detection element positioned between a sample stage on which the sample can be placed and the electron source, and an X-ray detection element positioned between the electron detection element and the electron source. Here, the electron detection element includes a scintillator that detects electrons emitted from the sample, and the X-ray detection element is configured to detect X-rays emitted from the sample and transmitted through the electron detection element.

[0010] The inspection element in one embodiment is an inspection element that can be incorporated into an inspection apparatus for detecting electrons and X-rays emitted from a sample by irradiating the sample placed on a sample stage with primary electrons generated by an electron source. Here, the inspection element includes an electron detection element that can be disposed between the sample stage and the electron source, and an X-ray detection element that can be disposed between the electron detection element and the electron source. The electron detection element includes a scintillator that detects electrons emitted from the sample, and the X-ray detection element is configured to detect X-rays emitted from the sample and transmitted through the electron detection element.

[0011] The inspection method in one embodiment includes a step of generating primary electrons by an electron source and irradiating the sample therewith, and a step of detecting electrons emitted from the sample by an electron detection element located between the sample stage on which the sample is disposed and the electron source and including a scintillator, and detecting, by an X-ray detection element located between the electron detection element and the electron source, X-rays emitted from the sample and transmitted through the electron detection element.

Advantages of the Invention

[0012] According to one embodiment, the performance of the inspection apparatus can be improved.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

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Figure 8

Embodiments for Carrying Out the Invention

[0014] In all the diagrams for explaining the embodiments, the same members are basically given the same reference numerals, and the repeated explanations thereof are omitted. Note that, for the sake of clarity of the drawings, hatching may be added even to a plan view.

[0015] <Configuration of the Inspection Device> FIG. 1 is a diagram showing a schematic configuration of the inspection device 100. In FIG. 1, the inspection device 100 includes an electron source 10, a convergence lens 11, a deflector 12, an objective lens 13, a sample stage 14, an inspection element 50, and a control unit 60.

[0016] The electron source 10 is configured to generate a plurality of primary electrons. The convergence lens 11 has a function of converging a primary electron beam composed of a plurality of primary electrons generated by the electron source 10, and the objective lens 13 has a function of forming an image of the primary electron beam on the sample 20 disposed on the sample stage 14. Further, the deflector 12 is configured to be able to change the traveling direction of the primary electron beam, and by this deflector 12, the irradiation position of the primary electron beam on the sample 20 can be scanned along the inspection range.

[0017] The inspection element 50 is configured to be able to detect electrons and X-rays emitted by irradiating the sample 20 with primary electrons, and includes an electron detection element 30 for detecting electrons and an X-ray detection element 40 for detecting X-rays.

[0018] As shown in FIG. 1, the electron detection element 30 is provided between the sample stage 14 on which the sample 20 is placed and the electron source 10. More specifically, the electron detection element 30 is provided between the sample stage 14 and the objective lens 13. On the other hand, the X-ray detection element 40 is provided between the electron detection element 30 and the electron source 10. More specifically, the X-ray detection element 40 is provided between the electron detection element 30 and the objective lens 13.

[0019] The electron detection element 30 is configured to include, for example, a scintillator that detects electrons emitted from the sample 20 and a photomultiplier tube that amplifies the light generated by the scintillator. The X-ray detection element 40 is configured to detect X-rays emitted from the sample 20 and transmitted through the electron detection element 30, and is composed of, for example, a semiconductor detector typified by a silicon drift detector or a combination of a scintillator and a photomultiplier tube. In this embodiment, it is assumed that the electron detection element 30 is composed of a combination of a scintillator and a photomultiplier tube, and the X-ray detection element 40 is also composed of a combination of a scintillator and a photomultiplier tube.

[0020] FIG. 2(a) is a diagram schematically showing the planar shape of the electron detection element 30 when viewed in a plane perpendicular to the incident direction of the primary electrons, and FIG. 2(b) is a diagram schematically showing the planar shape of the X-ray detection element 40 when viewed in a plane perpendicular to the incident direction of the primary electrons.

[0021] As shown in Fig. 2(a), the planar shape of the electron detection element 30 has a concentric circular shape with a cavity through which primary electrons pass in the central portion, and the electron detection element 30 is composed of a so-called "annular type element". Similarly, as shown in Fig. 2(b), the planar shape of the X-ray detection element 40 has a concentric circular shape with a cavity through which primary electrons pass in the central portion, and the X-ray detection element 40 is also composed of a so-called "annular type element".

[0022] The inspection element 50 configured as described above is incorporated into an inspection apparatus 100 that detects electrons and X-rays emitted from a sample 20 by irradiating the sample 20 disposed on the sample stage 14 with primary electrons (primary electron beam) generated by the electron source 10, and is not only integrally manufactured and sold, but may also be manufactured and sold alone as the inspection element 50.

[0023] Next, the control unit 60 is configured to control the operation of the inspection apparatus 100. Specifically, the control unit 60 is configured to perform control for converging the primary electron beam by the condenser lens 11 and the objective lens 13, control for scanning the primary electron beam by the deflector 12, control for performing signal processing on the output signal from the inspection element 50, and control for image generation processing and image display processing based on the output signal from the inspection element 50. As described above, the inspection apparatus 100 in the present embodiment is configured.

[0024] <Operation of the inspection apparatus> Subsequently, the operation of the inspection apparatus 100 will be described with reference to Fig. 1. First, the sample 20 is placed on the sample stage 14. Then, at the electron source 10, a plurality of primary electrons are generated, and a primary electron beam composed of the plurality of primary electrons is emitted from the electron source 10. The primary electron beam emitted from the electron source 10 is converged by the condenser lens 11 and then passes through the deflector 12, whereby the traveling direction is adjusted. Thereafter, the primary electron beam whose traveling direction has been adjusted by the deflector 12 is irradiated onto the first region of the sample 20 by the objective lens 13.

[0025] In the first region of the sample 20, when the primary electron beam is irradiated, for example, as a result of the primary electrons colliding with the electrons bound to the atoms (molecules) constituting the sample 20, the electrons bound to the atoms constituting the sample 20 are scattered and fly out of the atoms. These ejected electrons are secondary electrons. In addition, the primary electrons may be scattered by the atoms constituting the sample 20 and backscattered, and the electrons that are backscattered and ejected from the sample 20 are backscattered electrons.

[0026] Thus, when the primary electron beam is irradiated onto the sample 20, secondary electrons and backscattered electrons are ejected from the sample 20. Furthermore, X-rays are emitted by bremsstrahlung from the scattered secondary electrons, backscattered electrons, etc. From this, when the primary electron beam is irradiated onto the sample 20, not only secondary electrons and backscattered electrons (collectively referred to as "electrons") but also X-rays are ejected from the sample 20.

[0027] Subsequently, the "electrons" ejected from the sample 20 enter the electron detection element 30 disposed between the objective lens 13 and the sample stage 14. Then, the "electrons" that have entered the electron detection element 30 are converted into light by a scintillator, which is a component of the electron detection element 30. After that, the light converted by the scintillator is photoelectrically converted and amplified by a photomultiplier tube, which is a component of the electron detection element 30, and is output as an output signal from the electron detection element 30.

[0028] On the other hand, the X-rays ejected from the sample 20 pass through the electron detection element 30 and then enter the X-ray detection element 40 disposed between the objective lens 13 and the electron detection element 30. Then, the X-rays that have entered the X-ray detection element 40 are converted into light by a scintillator, which is a component of the X-ray detection element 40. After that, the light converted by the scintillator is photoelectrically converted and amplified by a photomultiplier tube, which is a component of the X-ray detection element 40, and is output as an output signal from the X-ray detection element 40.

[0029] Next, the output signal output from the electron detection element 30 is converted into, for example, an image signal, and based on this image signal, an electron image is acquired and the electron image is displayed. On the other hand, the output signal output from the X-ray detection element 40 is converted into, for example, an image signal, and based on this image signal, an X-ray image is acquired and the X-ray image is displayed.

[0030] Thereafter, the traveling direction of the primary electron beam is changed by the deflector 12, and the primary electron beam is scanned from the first region to the second region of the sample 20. And in the second region of the sample 20, the same operation as the operation in the first region is repeated. In this way, the inspection apparatus 100 operates.

[0031] <Features in the Embodiment> Subsequently, the feature points in this embodiment will be described. The first feature point in this embodiment is that, for example, as shown in FIG. 1, in the inspection apparatus 100 including the electron detection element 30 and the X-ray detection element 40, the electron detection element 30 is disposed between the sample stage 14 on which the sample 20 can be disposed and the electron source 10, and the X-ray detection element 40 is disposed between the electron detection element 30 and the electron source 10, and in a plan view, the electron detection element 30 and the X-ray detection element 40 are disposed so as to overlap each other.

[0032] Accordingly, according to the first feature point, the "electrons" emitted from the sample 20 are absorbed by the electron detection element 30 disposed in front of the X-ray detection element 40. As a result, the incidence of "electrons" on the X-ray detection element 40 is suppressed, and thereby, the detection accuracy of X-rays by the X-ray detection element 40 can be improved. That is, since an output signal is also generated when "electrons" enter the X-ray detection element 40, the output signal caused by this "electron" becomes noise. Therefore, in order to improve the detection accuracy of X-rays, it is desirable to prevent "electrons" from entering the X-ray detection element 40 as much as possible.

[0033] Regarding this point, according to the first feature point, since the electron detection element 30 is arranged on the side closer to the sample 20, the electron detection element 30 functions as a shielding member that suppresses the incidence of "electrons" on the X-ray detection element 40. Therefore, according to the first feature point, the detection accuracy of X-rays by the X-ray detection element 40 can be improved.

[0034] Here, in order for the electron detection element 30 to function as a shielding member, it is desirable that the film thickness of the electron detection element 30 has a sufficient film thickness to absorb "electrons" and has a sufficient density to absorb "electrons". In this case, since the number of "electrons" absorbed by the electron detection element 30 increases, according to the first feature point, the detection efficiency of "electrons" in the electron detection element 30 can also be improved.

[0035] Note that since the X-rays emitted from the sample 20 have a high transmittance, they pass through the electron detection element 30 in front and enter the X-ray detection element 40. Therefore, even if the configuration of the first feature point is adopted, there is no problem in the detection of X-rays.

[0036] From the above, according to the first feature point, without sacrificing the incidence of X-rays on the X-ray detection element 40, the electron detection element 30 can be made to function as a shielding member that suppresses the incidence of "electrons" on the X-ray detection element 40. As a result, according to the inspection apparatus 100 in the present embodiment, the detection accuracy of X-rays can be improved.

[0037] Next, the second feature point in the present embodiment is that, for example, as shown in FIGS. 2(a) and 2(b), the electron detection element 30 is an "annular type element" and the X-ray detection element 40 is also an "annular type element". In other words, the second feature point is that the planar shape of the electron detection element 30 has a concentric circular shape with a cavity through which primary electrons pass in the central portion, and similarly, the planar shape of the X-ray detection element 40 also has a concentric circular shape with a cavity through which primary electrons pass in the central portion.

[0038] Accordingly, according to the second feature point, the solid angle at which "electrons" are incident from the sample 20 on the electron detection element 30 and the solid angle at which X-rays are incident from the sample 20 on the X-ray detection element 40 can be increased. This means that "electrons" can be efficiently converted into light by the electron detection element 30 and X-rays can be efficiently converted into light by the X-ray detection element 40. Therefore, according to the second feature point, the detection efficiency of "electrons" and the detection efficiency of X-rays in the inspection apparatus 100 can be improved.

[0039] From the above, according to the inspection apparatus 100 in the present embodiment, the performance of the inspection apparatus 100 can be improved by the synergistic effect of the first feature point and the second feature point described above.

[0040] <Verification of Effects> The verification results regarding the improvement of the X-ray detection accuracy in the inspection apparatus 100 according to the above-described feature points will be described. The verification was performed by calculating the backscattered electron intensity (BSE (Back Scattered Electron) intensity) and the X-ray intensity for a deep-hole sample. Specifically, the verification was performed by calculating the SNR (Signal Noise Ratio: contrast) based on the signal intensity from the bottom of the deep hole.

[0041] FIG. 3(a) is a graph showing the calculation result of "SNR" calculated based on the backscattered electron intensity from the bottom of the deep hole, and FIG. 3(b) is a graph showing the calculation result of "SNR" calculated based on the X-ray intensity from the bottom of the deep hole.

[0042] As shown in FIGS. 3(a) and 3(b), the "SNR" based on the reflected electron intensity is about 2 (the points surrounded by circles), while the "SNR" based on the X-ray intensity is found to be about 8 (the points surrounded by circles). This means that the "SNR" based on the X-ray intensity has a contrast about 4 times higher than that based on the reflected electron intensity. That is, according to the above verification results, it can be seen that the sensitivity to the information from the bottom of the deep hole is better when using the detection of X-rays by the X-ray detection element 40 than when using the detection of reflected electrons by the electron detection element 30. From such verification results, it can be confirmed that according to the inspection apparatus 100 in the present embodiment, by using the output from the X-ray detection element 40, information from the bottom of the deep hole can be accurately detected. That is, by using the inspection apparatus 100 in the present embodiment, for example, etching defects of deep holes with a high aspect ratio can be inspected with high accuracy.

[0043] <Modification Example> Next, a modification example will be described. FIG. 4 is a diagram for explaining the configuration of the modification example. In FIG. 4, in this modification example, between the electron detection element 30 and the X-ray detection element 40, a crosstalk suppression unit 70 for suppressing crosstalk between the light generated from the scintillator included in the electron detection element 30 and the light generated from the scintillator included in the X-ray detection element 40 is provided.

[0044] Thereby, according to this modification example, it is possible to suppress the light generated in the electron detection element 30 from entering the X-ray detection element 40 and being detected by the photomultiplier tube of the X-ray detection element 40, and the light generated in the X-ray detection element 40 from entering the electron detection element 30 and being detected by the photomultiplier tube of the electron detection element 30. That is, according to this modification example, in each of the electron detection element 30 and the X-ray detection element 40, the superposition of noise signals can be reduced. As a result, according to this modification example, the detection accuracy of "electrons" by the electron detection element 30 and the detection accuracy of X-rays by the X-ray detection element 40 can be improved.

[0045] For example, the crosstalk suppression unit 70 can be composed of a shielding film that shields the light generated from the scintillator included in the electron detection element 30 and the light generated from the scintillator included in the X-ray detection element 40.

[0046] However, the crosstalk suppression unit 70 is not only composed of the above-described shielding film, but also, for example, a film having a refractive index different from the refractive index of the material constituting the electron detection element 30 and the refractive index of the material constituting the X-ray detection element 40, or It can be composed of a spatial region having a refractive index different from the refractive index of the material constituting the electron detection element 30 and the refractive index of the material constituting the X-ray detection element 40.

[0047] Specifically, the crosstalk suppression unit 70 can be composed of a film having a refractive index smaller than the refractive index of the material constituting the electron detection element 30 and the refractive index of the material constituting the X-ray detection element 40, or a spatial region having a refractive index smaller than the refractive index of the material constituting the electron detection element 30 and the refractive index of the material constituting the X-ray detection element 40.

[0048] In this case, the light generated from the scintillator included in the electron detection element 30 is totally reflected by the refractive index difference at the boundary between the electron detection element 30 and the crosstalk suppression unit 70. In other words, the light generated from the scintillator included in the electron detection element 30 is confined inside the electron detection element 30. Similarly, the light generated from the scintillator included in the X-ray detection element 40 is totally reflected by the refractive index difference at the boundary between the X-ray detection element 40 and the crosstalk suppression unit 70. In other words, the light generated from the scintillator included in the X-ray detection element 40 is confined inside the X-ray detection element 40. As a result, the intrusion of the light generated in the electron detection element 30 into the X-ray detection element 40 and the intrusion of the light generated in the X-ray detection element 40 into the electron detection element 30 are suppressed, and as a result, the detection accuracy of "electrons" by the electron detection element 30 and the detection accuracy of X-rays by the X-ray detection element 40 can be improved.

[0049] <Further points of ingenuity> As described above, the inspection apparatus 100 in the present embodiment includes an electron detection element 30 that detects "electrons" emitted from the sample 20 and an X-ray detection element 40 that detects X-rays emitted from the sample 20. Here, the X-ray detection element 40 has an advantage that it can accurately detect information from the bottom of a deep hole, for example. On the other hand, the electron detection element 30 has an advantage that it can accurately detect the surface shape (information from the surface) of a deep hole.

[0050] Therefore, by combining the advantages of the X-ray detection element 40 and the electron detection element 30, for example, based on information about the bottom of a deep hole and information about the surface shape, it is considered possible to accurately inspect etching defects of deep holes with a high aspect ratio and surface shape defects (defects in the opening diameter) of deep holes. That is, since the inspection apparatus 100 in the present embodiment includes the electron detection element 30 and the X-ray detection element 40 having different advantages, it is considered possible to further improve the performance of the inspection apparatus 100 by devising a combination of their respective advantages. This point of ingenuity will be described below.

[0051] <<Functional Block Configuration of Control Unit>> FIG. 5 is a diagram showing the functional block configuration of the control unit 60. In FIG. 5, the control unit 60 includes an input unit 201, a first image signal conversion unit 202, a second image signal conversion unit 203, an electron image acquisition unit 204, an X-ray image acquisition unit 205, a first feature image acquisition unit 206, a second feature image acquisition unit 207, a composite image acquisition unit 208, an output unit 209, and a data storage unit 210.

[0052] The input unit 201 is configured to input a first output signal output from the electron detection element 30 and a second output signal output from the X-ray detection element 40. Here, for example, if it is configured such that the electron detection element 30 includes a first scintillator and the X-ray detection element 40 includes a second scintillator, the first output signal output from the electron detection element 30 is a signal based on the light obtained by converting "electrons" with the first scintillator. Also, the second output signal output from the X-ray detection element 40 is a signal based on the light obtained by converting X-rays with the second scintillator. At this time, the first output amount output from the electron detection element 30 is a signal amount based on the amount of light obtained by converting "electrons" with the first scintillator. Also, the second output amount output from the X-ray detection element 40 is a signal amount based on the amount of light obtained by converting X-rays with the second scintillator.

[0053] The first image signal conversion unit 202 has a function of converting the first output signal input to the input unit 201 into a first image signal. On the other hand, the second image signal conversion unit 203 has a function of converting the second output signal input to the input unit 201 into a second image signal.

[0054] Next, the electron image acquisition unit 204 is configured to generate an electron image based on the first image signal converted by the first image signal conversion unit 202. Then, the electron image acquired by the electron image acquisition unit 204 is stored in, for example, the data storage unit 210.

[0055] The X-ray image acquisition unit 205 is configured to generate an X-ray image based on the second image signal converted by the second image signal conversion unit 203. Then, the X-ray image acquired by the X-ray image acquisition unit 205 is stored in, for example, the data storage unit 210. The gradation of the pixels of the X-ray image is based on the amount of light obtained by converting X-rays with the scintillator, and the amount of light may be the sum of the amounts of light within a certain time, or may be the sum of the units with the amount of light equal to or more than (or less than or equal to) the reference amount of light within a certain time as one unit.

[0056] After the first feature image acquisition unit 206 reads out the electronic image generated by the electronic image acquisition unit 204 from the data storage unit 210, it is configured to acquire a first feature image obtained by extracting features from this electronic image. Then, the first feature image is stored in the data storage unit 210.

[0057] After the second feature image acquisition unit 207 reads out the X-ray image generated by the X-ray image acquisition unit 205 from the data storage unit 210, it is configured to acquire a second feature image obtained by extracting features from this X-ray image. Then, the second feature image is stored in the data storage unit 210.

[0058] Subsequently, the composite image acquisition unit 208 is configured to acquire a composite image that combines the features included in the first feature image and the features included in the second feature image based on the first feature image acquired by the first feature image acquisition unit 206 and the second feature image acquired by the second feature image acquisition unit 207. This composite image is stored in the data storage unit 210, for example.

[0059] The output unit 209 is configured to output the composite image acquired by the composite image acquisition unit 208 to the display unit 80, for example. Thereby, the composite image is displayed on the display unit 80. The control unit 60 is configured as described above.

[0060] <<Operation of the inspection device>> Next, the operation of the inspection device 100 corresponding to further improvements will be described. FIG. 6 is a flowchart for explaining the operation of the inspection device 100. In FIG. 6, first, the variable N representing the Nth region of the sample 20 is set to "N = 1" (S101). Then, the primary electrons (primary electron beam) emitted from the electron source 10 are irradiated onto the first region of the sample 20 (S102). As a result, "electrons" and X-rays are emitted from the first region of the sample 20. The emitted "electrons" are detected by the electron detection element 30 (S103A). On the other hand, the emitted X-rays pass through the electron detection element 30 and are detected by the X-ray detection element 40 (S103B). For example, the detection of the "electrons" emitted from the first region of the sample 20 by the electron detection element 30 and the detection of the X-rays emitted from the first region of the sample 20 by the X-ray detection element 40 are performed simultaneously.

[0061] Next, when "electrons" are detected by the electron detection element 30, a first output signal corresponding to the detection of the "electrons" is output from the electron detection element 30. Then, the first output signal output from the electron detection element 30 is input to the input unit 201 and then converted into a first image signal in the first image signal conversion unit 202 (S104A).

[0062] On the other hand, when X-rays are detected by the X-ray detection element 40, a second output signal corresponding to the detection of the X-rays is output from the X-ray detection element 40. Then, the second output signal output from the X-ray detection element 40 is input to the input unit 201 and then converted into a second image signal in the second image signal conversion unit 203 (S104B).

[0063] Subsequently, the electron image acquisition unit 204 acquires an electron image based on the first image signal converted by the first image signal conversion unit 202 (S105A). On the other hand, the X-ray image acquisition unit 205 acquires an X-ray image based on the second image signal converted by the second image signal conversion unit 203 (S105B). The acquired electron image and X-ray image are stored in the data storage unit 210.

[0064] After that, the first feature image acquisition unit 206 extracts features from the electronic image acquired by the electronic image acquisition unit 204 to acquire a first feature image (S106A). On the other hand, the second feature image acquisition unit 207 extracts features from the X-ray image acquired by the X-ray image acquisition unit 205 to acquire a second feature image (S106B). Here, the acquired first feature image and second feature image are stored in the data storage unit 210.

[0065] Then, the composite image acquisition unit 208 acquires a composite image that combines the features included in the first feature image and the features included in the second feature image based on the first feature image acquired by the first feature image acquisition unit 206 and the second feature image acquired by the second feature image acquisition unit 207 (S107). At this time, the acquired composite image is stored in the data storage unit 210.

[0066] Next, the output unit 209 outputs the composite image acquired by the composite image acquisition unit 208 to, for example, the display unit 80 (S108). Thereby, the composite image is displayed on the display unit 80.

[0067] After that, the control unit 60 determines whether the Nth region of the sample 20 is the final scanning region (Nmax) of the inspection (S109). As a result, if the Nth region of the sample 20 is not the final scanning region (Nmax) of the inspection, "N = N + 1" is set, and the process returns to S102, and the same operation is repeated in the (N + 1)th region of the sample 20. On the other hand, if the Nth region of the sample 20 is the final scanning region (Nmax) of the inspection, the operation of the inspection apparatus 100 is terminated. In the above manner, the inspection apparatus 100 operates.

[0068] <<Features of further improvements>> The feature of the further improvement lies in generating a composite image that combines the features included in the electron image based on the output from the electron detection element 30 and the features included in the X-ray image based on the output from the X-ray detection element 40. Then, by performing an inspection of the sample 20 based on the generated composite image, a high-precision inspection can be carried out. That is, according to the further improvement, the advantages of the electron detection element 30 and the advantages of the X-ray detection element 40 can be combined and effectively utilized, so that the inspection performance in the inspection apparatus 100 can be improved.

[0069] <<Specific Example>> Hereinafter, it will be described using specific examples. FIG. 7 is a schematic diagram showing a deep-hole sample. In FIG. 7, deep-hole CNT1 and deep-hole CNT2 are illustrated. Deep-hole CNT2 is etched so as to reach the wiring WL and shows a normal deep hole. On the other hand, deep-hole CNT1 does not reach the wiring WL and shows a deep hole with an etching defect. Hereinafter, it is considered to inspect the deep-hole sample shown in FIG. 7 with the inspection apparatus 100 in the present embodiment.

[0070] FIG. 8(a) is a diagram schematically showing an electron image generated based on the output from the electron detection element 30, and FIG. 8(b) is a diagram schematically showing an X-ray image generated based on the output from the X-ray detection element 40. Further, FIG. 8(c) is a diagram showing a composite image combining the features of the electron image and the features of the X-ray image.

[0071] In FIG. 8(a), in the electron detection element 30, since it is difficult to obtain information from the bottom of the deep hole with a high aspect ratio, there is no difference in the contrast between deep-hole CNT1 and deep-hole CNT2 included in the electron image. From this, it is impossible to distinguish the deep-hole CNT1 with an etching defect and the normal deep-hole CNT2 shown in FIG. 7 only by the electron image.

[0072] However, the advantage of the electron image based on the output of the electron detection element 30 is that it accurately reflects the surface shape of the sample. For this reason, the aperture diameters of the deep hole CNT1 and the deep hole CNT2 in Fig. 8(a) are accurate. That is, the feature (advantage) of the electron image shown in Fig. 8(a) is that the aperture diameters of the deep hole CNT1 and the deep hole CNT2 are accurate.

[0073] Next, in Fig. 8(b), since the X-ray detection element 40 can obtain information from the bottom of the deep hole with a high aspect ratio, it can be seen that there is a difference in contrast between the deep hole CNT1 and the deep hole CNT2 included in the X-ray image. That is, in the X-ray image shown in Fig. 8(b), based on the contrast difference, the defective etched deep hole CNT1 and the normal deep hole CNT2 shown in Fig. 7 can be distinguished. Thus, the feature (advantage) of the X-ray image shown in Fig. 8(b) is that a contrast difference occurs between the defective etched deep hole CNT1 and the normal deep hole CNT2.

[0074] However, it is difficult for the X-ray image based on the output of the X-ray detection element 40 to accurately reflect the surface shape of the sample more than the electron image based on the output of the electron detection element 30. That is, in the X-ray image shown in Fig. 8(b), the aperture diameters of the deep hole CNT1 and the deep hole CNT2 are inaccurate and are magnified compared to the electron image shown in Fig. 8(a). That is, in the X-ray image shown in Fig. 8(b), the aperture diameters of the deep hole CNT1 and the deep hole CNT2 are inaccurate and are more blurred than the electron image shown in Fig. 8(a).

[0075] As described above, the advantage of the electron image shown in Fig. 8(a) is that the aperture diameters of the deep hole CNT1 and the deep hole CNT2 are accurate, and the advantage of the X-ray image shown in Fig. 8(b) is that the defective etched deep hole CNT1 and the normal deep hole CNT2 can be distinguished by the contrast difference. Therefore, in the inspection apparatus 100, a composite image is generated by combining the advantage of the electron image shown in Fig. 8(a) and the advantage of the X-ray image shown in Fig. 8(b).

[0076] As shown in Fig. 8(c), it can be seen that the composite image incorporates the advantages of the electron image shown in Fig. 8(a) (the contours of the deep-hole CNT1 and deep-hole CNT2) and the advantages of the X-ray image shown in Fig. 8(b) (the contrast difference between the deep-hole CNT1 and deep-hole CNT2).

[0077] Therefore, according to the inspection using the composite image shown in Fig. 8(c), the defective deep-hole CNT1 with etching defects can be identified from the contrast difference between the deep-hole CNT1 and deep-hole CNT2. Furthermore, the presence or absence of abnormal opening diameters can be inspected from the contours of the deep-hole CNT1 and deep-hole CNT2. From the above, according to the inspection apparatus 100 having "further points for improvement", the inspection accuracy can be improved. In other words, the performance of the inspection apparatus 100 can be improved.

[0078] As described above, the invention made by the present inventor has been specifically described based on its embodiments. However, it goes without saying that the present invention is not limited to the above embodiments and can be variously modified without departing from the gist thereof.

Explanation of Reference Numerals

[0079] 10 Electron source 11 Converging lens 12 Deflector 13 Objective lens 14 Sample stage 20 Sample 30 Electron detection element 40 X-ray detection element 50 Inspection element 60 Control unit 70 Crosstalk suppression unit 80 Display unit 100 Inspection apparatus 201 Input unit 202 First image signal conversion unit 203 Second image signal conversion unit 204 Electron image acquisition unit 205 X-ray image acquisition unit 206 First feature image acquisition unit 207 Second feature image acquisition unit 208 Synthetic Image Acquisition Unit 209 Output Unit 210 Data Storage Unit CNT1 Deep Hole CNT2 Deep Hole WL Wiring

Claims

1. An electron source that generates primary electrons and irradiates a sample therewith, An electron detection element positioned between a sample stage on which the sample can be placed and the electron source, An X-ray detection element positioned between the electron detection element and the electron source, A inspection apparatus comprising: The electron detection element includes a first scintillator that detects electrons emitted from the sample, The X-ray detection element is configured to detect X-rays emitted from the sample and transmitted through the electron detection element, The X-ray detection element includes a second scintillator, A crosstalk suppression unit that suppresses crosstalk between light generated from the first scintillator included in the electron detection element and light generated from the second scintillator included in the X-ray detection element is provided between the electron detection element and the X-ray detection element. Inspection apparatus.

2. In the inspection apparatus according to claim 1, The electron detection element is an annular element, The X-ray detection element is an annular element. Inspection apparatus.

3. In the inspection apparatus according to claim 1, When viewed in a plane perpendicular to the incident direction of the primary electrons, The planar shape of the electron detection element is a concentric circle shape, The planar shape of the X-ray detection element is a concentric circle shape. Inspection apparatus.

4. In the inspection apparatus according to claim 1, Detection of the electrons in the electron detection element and detection of the X-rays in the X-ray detection element are performed simultaneously. Inspection apparatus.

5. In the inspection apparatus according to claim 1, The inspection apparatus is A first image signal conversion unit that converts an output from the electron detection element into a first image signal, An electron image acquisition unit that acquires an electron image based on the first image signal, A second image signal conversion unit that converts an output from the X-ray detection element into a second image signal, An X-ray image acquisition unit that acquires an X-ray image based on the second image signal, Having an inspection apparatus.

6. In the inspection apparatus according to claim 5, The amount of output from the X-ray detection element is a signal amount based on the amount of light obtained by converting the X-rays with the second scintillator. Inspection apparatus.

7. In the inspection apparatus according to claim 6, The gradation of the pixels in the X-ray image is an amount based on the total amount of light converted by the second scintillator of the X-ray detection element within a certain period of time. Inspection apparatus.

8. In the inspection apparatus according to claim 5, When irradiating the first region of the sample with the primary electrons, the electron detection element detects electrons emitted from the first region, the X-ray detection element detects X-rays emitted from the first region, the electron image acquisition unit acquires a first electron image corresponding to the first region, the X-ray image acquisition unit acquires a first X-ray image corresponding to the first region, an inspection apparatus.

9. In the inspection apparatus according to claim 8, the inspection apparatus, a first feature image acquisition unit that acquires a first feature image obtained by extracting features of the first electron image, a second feature image acquisition unit that acquires a second feature image obtained by extracting features of the first X-ray image, a composite image acquisition unit that acquires a composite image from the first feature image and the second feature image, An inspection apparatus having.

10. In the inspection apparatus according to claim 1, The inspection apparatus, wherein the incidence of electrons emitted from the sample on the X-ray detection element is suppressed by the electron detection element provided between the sample stage and the X-ray detection element.

11. In the inspection apparatus according to claim 1, The crosstalk suppression unit is composed of a shielding film that shields light generated from the first scintillator included in the electron detection element and light generated from the second scintillator included in the X-ray detection element, an inspection apparatus.

12. In the inspection apparatus according to claim 1, The crosstalk suppression unit is composed of a film having a refractive index different from the refractive index of the material constituting the electron detection element and the refractive index of the material constituting the X-ray detection element, or a spatial region having a refractive index different from the refractive index of the material constituting the electron detection element and the refractive index of the material constituting the X-ray detection element, an inspection apparatus.

13. An inspection element that can be incorporated into an inspection apparatus for detecting electrons and X-rays emitted from a sample by irradiating the sample placed on a sample stage with primary electrons generated by an electron source, the inspection element, an electron detection element that can be disposed between the sample stage and the electron source, an X-ray detection element that can be disposed between the electron detection element and the electron source, comprising, the electron detection element includes a first scintillator that detects electrons emitted from the sample, the X-ray detection element is configured to detect X-rays emitted from the sample and transmitted through the electron detection element, the X-ray detection element includes a second scintillator, A detection element, wherein a crosstalk suppression unit for suppressing crosstalk between light generated from the first scintillator included in the electron detection element and light generated from the second scintillator included in the X-ray detection element is provided between the electron detection element and the X-ray detection element.

14. In the detection element according to claim 13, the electron detection element is an annular element, and the X-ray detection element is an annular element.

15. In the detection element according to claim 13, when viewed in a plane perpendicular to the incident direction of the primary electrons, the planar shape of the electron detection element is a concentric circle shape, and the planar shape of the X-ray detection element is a concentric circle shape.

16. In the detection element according to claim 13, detection of the electrons in the electron detection element and detection of the X-rays in the X-ray detection element are performed simultaneously.

17. In the detection element according to claim 13, the output amount from the X-ray detection element is a signal amount based on the amount of light obtained by converting the X-rays with the second scintillator.

18. In the detection element according to claim 13, incidence of the electrons emitted from the sample onto the X-ray detection element is suppressed by the electron detection element provided between the sample stage and the X-ray detection element.

Images