JP2020061240A - Measurement device and measurement method of front face of sample - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure a sample shape efficiently and with high accuracy. SOLUTION: This is a measuring device that measures the shape of a sample having uneven portions by irradiating a charged particle beam, and by irradiating the sample with the charged particle beam at an arbitrary angle, the irradiation position and emitted electrons are measured. A profile showing the relationship between the intensities is generated, and an analysis process for analyzing the shape of the sample is executed using the two profiles. [Selection diagram] Fig. 1

Description

  The present invention relates to an apparatus and method for measuring the shape of a sample using a charged particle beam.

  In semiconductor process development, it is necessary to confirm the depth and taper angle of a trench and the presence or absence of a notch in an etched sample.

  A method using a scanning electron microscope is known as a method of measuring the shape of a sample such as a semiconductor. In the following description, the scanning electron microscope is also referred to as SEM.

  In the above-described measurement method, the SEM scans the sample with a primary electron beam and detects emitted electrons (Auger electrons, secondary electrons, reflected electrons, and the like) emitted from the sample using a detector. The detection signal in the emission direction corresponding to the emission electron detected by the detector is sampled at a constant cycle. The sampling of the emitted electron signal is performed in synchronization with the scanning signal, and the extraction signal corresponding to the pixel of the two-dimensional image is obtained. The SEM generates an image by converting the intensity of the extracted signal into brightness, or generates an image from the relationship between the coordinates of the scanning position of the primary electron beam and the brightness.

  For example, in Patent Document 1, "a sample stage on which a sample is mounted and one of a lens barrel are set on the sample stage by controlling a deflector of a scanning electron microscope capable of setting an arbitrary tilt angle. A pattern shape measuring method of irradiating an electron beam on a measuring section of a sample placed thereon, image-processing a secondary electron signal from the measuring section, and measuring a pattern shape of the measuring section based on the image-processed signal. In the first step, the inclination angle is set to zero, and the secondary electron signal when the measuring section is irradiated with the electron beam is image-processed to calculate the bottom dimension of the pattern of the measuring section. A second step of setting a predetermined angle and performing image processing of a secondary electron signal when the measuring section is irradiated with an electron beam to obtain the number of pixels in the taper section of the pattern of the measuring section; The second different from the predetermined angle of It is determined by the third step of setting the constant angle and subjecting the secondary electron signal when the measuring section is irradiated with the electron beam to the image processing to obtain the number of pixels of the taper section, and the second and third steps. A fourth step of calculating the taper angle and depth of the pattern based on the number of pixels of the taper portion and the first and second predetermined angles; and a change in the intensity of the secondary electron signal of the taper portion. A fifth step of obtaining the profile of the tapered portion based on the sixth step, and a sixth step of calculating the surface area of the measurement pattern based on the bottom dimension of the pattern and the profile of the tapered portion obtained in the first and fifth steps. And a pattern shape measuring method.

JP-A-3-233309

  Patent Document 1 does not consider the structure of the profile obtained by irradiating the surface of the sample with an inclined electron beam. In order to improve the measurement accuracy, it is necessary to consider the above structure. Further, in Patent Document 1, it is not possible to determine the presence or absence of a notch.

  The present invention provides an apparatus and method capable of measuring the shape of a sample efficiently and with high accuracy.

  A typical example of the invention disclosed in the present application is as follows. That is, a measuring device for irradiating a charged particle beam to measure the shape of a sample having an uneven portion, the particle source outputting the charged particle beam, a lens for focusing the charged particle beam, and the charged particle beam. A detector for detecting a signal of an emission electron emitted from the sample irradiated with, and a control device for controlling the output of the charged particle beam and the detection of the signal of the emission electron, the control device comprising: By irradiating the sample with the charged particle beam at an arbitrary angle, a profile indicating the relationship between the irradiation position and the intensity of the emitted electrons is generated, and the shape of the sample is analyzed using the two profiles. Is executed and the result of the analysis process is output.

  According to the present invention, the shape of a sample can be measured efficiently and with high accuracy. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

3 is a diagram showing an example of the configuration of a scanning electron microscope of Example 1. FIG. 6 is a flowchart illustrating an example of processing executed by the scanning electron microscope according to the first embodiment. 5 is a diagram showing the relationship between the shape of the sample and the line profile of Example 1. FIG. 5 is a diagram showing the relationship between the shape of the sample and the line profile of Example 1. FIG. 5 is a diagram showing the relationship between the shape of the sample and the line profile of Example 1. FIG. 5 is a diagram showing the relationship between the shape of the sample and the line profile of Example 1. FIG. FIG. 6 is a diagram illustrating characteristics of a characteristic amount A (θ) according to the first embodiment. FIG. 6 is a diagram illustrating characteristics of a characteristic amount A (θ) according to the first embodiment. FIG. 6 is a diagram illustrating characteristics of a characteristic amount A (θ) according to the first embodiment. 6 is a flowchart illustrating an example of an analysis process executed by the scanning electron microscope according to the first embodiment. 6 is a diagram showing an example of the configuration of a scanning electron microscope of Example 2. FIG. 9 is a flowchart illustrating an example of processing executed by the scanning electron microscope according to the second embodiment. 9 is a flowchart illustrating an example of an analysis process executed by the scanning electron microscope according to the second embodiment. FIG. 7 is a diagram showing the relationship between the shape of the side wall of the trench and the line profile of the sample of Example 2. FIG. 7 is a diagram showing the relationship between the shape of the side wall of the trench and the line profile of the sample of Example 2. FIG. 7 is a diagram showing the relationship between the shape of the side wall of the trench and the line profile of the sample of Example 2. FIG. 7 is a diagram showing the relationship between the shape of the side wall of the trench and the line profile of the sample of Example 2. 5 is a diagram showing characteristics of a line profile of a sample having a notch of Example 2. FIG. 5 is a diagram showing characteristics of a line profile of a sample having a notch of Example 2. FIG. 5 is a diagram showing characteristics of a line profile of a sample having a notch of Example 2. FIG. FIG. 8 is a diagram showing an example of information included in an analysis result output by the scanning electron microscope of the second embodiment. FIG. 8 is a diagram showing an example of information included in an analysis result output by the scanning electron microscope of the second embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention should not be construed as being limited to the description of the examples below. It is easily understood by those skilled in the art that the specific configuration can be changed without departing from the idea or the spirit of the present invention.

  In the configurations of the invention described below, the same or similar configurations or functions are designated by the same reference numerals, and overlapping description will be omitted.

  The notations such as “first”, “second”, and “third” in this specification and the like are given to identify components, and do not necessarily limit the number or order.

  The position, size, shape, range, etc. of each component shown in the drawings and the like may not represent the actual position, size, shape, range, etc. for easy understanding of the invention. Therefore, the present invention is not limited to the position, size, shape, range, etc. disclosed in the drawings and the like.

  FIG. 1 is a diagram illustrating an example of the configuration of the scanning electron microscope 10 according to the first embodiment.

  In the first embodiment, the scanning electron microscope 10 is used as an example of the measuring device (charged particle beam device) used for measuring the shape of the sample, but an electron microscope using an intermittent electron beam may be used.

  The scanning electron microscope 10 includes an electron optical system, a stage mechanism system, an SEM control system, a signal processing system, and an SEM operation system. More specifically, the scanning electron microscope 10 includes an electron optical system lens barrel 101 including an electron optical system and a stage mechanism system, and a control unit 102 including an SEM control system, a signal processing system, and an SEM operation system. It

  The electron optical system includes an electron gun 111, a deflector 113, an objective lens 115, and a detector 119. The electron gun 111 outputs a primary electron beam 112.

  The focus of the primary electron beam 112 is adjusted when passing through the deflector 113 and the objective lens 115. Further, the trajectory of the primary electron beam 112 is deflected when passing through the deflector 113, and the sample 116 is two-dimensionally scanned. Emitted electrons such as secondary electrons or reflected electrons emitted from the sample 116 irradiated with the primary electron beam 112 are detected by the detector 119. The emitted electron signal detected by the detector 119 is processed by the control unit 102. The two-dimensional image corresponding to the irradiation position of the primary electron beam 112 is displayed on the output device 125, for example.

  The stage mechanism system is composed of a sample holder 117 having a stage for mounting the sample 116. The stage is capable of tilt control and movement control in three-dimensional directions (XYZ axes). The sample 116 of Example 1 is assumed to be a semiconductor or the like that has been subjected to etching processing or the like. In addition, the sample 116 has unevenness such as a trench formed by etching.

  In the first embodiment, the primary electron beam 112 that is tilted at an arbitrary angle with respect to the perpendicular of the surface of the sample 116 is realized by tilting the stage. The irradiation of the above-mentioned primary electron beam 112 may be realized by adjusting the direction of the electron gun 111 or deflecting the deflector 113.

  The control unit 102 includes a calculation device 121, a storage device 122, a scanning signal control device 123, an input device 124, and an output device 125. The control unit 102 may include a storage medium such as an HDD (Hard Disk Drive) and an SSD (Solid State Drive).

  The arithmetic unit 121 executes predetermined arithmetic processing according to a program stored in the storage unit 122. The arithmetic unit 121 may be, for example, a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit).

  The storage device 122 stores a program executed by the arithmetic device 121 and data used by the program. The storage device 122 also includes a temporary storage area such as a work area used by the program. The storage device 122 may be, for example, a memory. The programs and data stored in the storage device 122 will be described later.

  The scanning signal control device 123 controls the scanning speed of the scanning electron beam. For example, the scanning signal control device 123 is connected so as to be able to communicate with the deflector 113.

  The input device 124 is a device for inputting data, and includes a keyboard, a mouse, a touch panel, and the like. The output device 125 is a device that outputs data, and includes a touch panel, a display, and the like.

  The storage device 122 stores a program that realizes the control module 131. The storage device 122 also stores line profile information 132.

  The storage device 122 may store programs and information (not shown). For example, the storage device 122 may store measurement condition information that manages measurement conditions such as acceleration voltage, irradiation current, scanning width (irradiation time), pixel split number (irradiation cycle), and timing delay. The storage device 122 may also store image management information that manages an electron microscope image such as a potential contrast image generated from the detected emitted electrons.

  The control module 131 controls each component of the electron optical system lens barrel 101. The control module 131 also generates an image from the signal of the secondary electron. The control unit 102 may include an image generation module that generates an image, in addition to the control module 131.

  The line profile information 132 is information for managing the line profile. The line profile is information in which pixels and the intensity of contrast in the pixels (intensity of the signal of the emitted electron) are associated with each other, and also information indicating the shape of the sample 116. The line profile of this embodiment is generated based on an image of an electron microscope image generated from secondary electrons.

  In this embodiment, the SEM control system is composed of the control module 131 and the scanning signal control device 123, the signal processing system is composed of the control module 131, and the SEM operation system is composed of the input device 124 and the output device 125.

  FIG. 2 is a flowchart illustrating an example of processing executed by the scanning electron microscope 10 according to the first embodiment. 3A, 3B, 3C, and 3D are diagrams showing the relationship between the shape and the line profile of the sample 116 of Example 1. FIG. 4A, FIG. 4B, and FIG. 4C are diagrams for explaining the characteristic of the characteristic amount A (θ) of the first embodiment.

  The scanning electron microscope 10 starts the process described below when a start request is received from the user or when the measurement conditions are satisfied.

  The scanning electron microscope 10 sets the angle θ at which the primary electron beam 112 is incident with respect to the direction perpendicular to the plane formed by the sample 116 (step S101).

  Specifically, the control module 131 sets the angle θ. The angle θ may be set based on the measurement condition information or may be set based on the input from the user. At this time, the scanning signal control device 123 controls the stage based on the angle θ.

  Next, the scanning electron microscope 10 irradiates the sample 116 with the primary electron beam 112 (step S102). At this time, the detector 119 detects the emitted electrons emitted from the sample 116 and outputs a signal of the emitted electrons to the control unit 102. The control module 131 of the control unit 102 stores the detection data in which the angle θ and the signal of the emitted electron are associated with each other in the storage device 122.

  Next, the scanning electron microscope 10 executes image processing using the emitted electron signal (step S103).

  For example, the control module 131 generates an electron microscope image using the signals of the emitted electrons detected in a certain time range. That is, an electron microscope image showing the shape of a part of the sample 116 is generated. At this time, the control module 131 generates one image by combining a plurality of electron microscope images.

  Next, the scanning electron microscope 10 determines whether or not the image is appropriate (step S104).

  For example, the control module 131 determines whether the orientations of the combined electron microscope images match. If the orientations of the combined electron microscope images match, the control module 131 determines that the images are suitable.

  When it is determined that the image is not appropriate, the scanning electron microscope 10 returns to step S102 and executes the same processing. The scanning electron microscope 10 may return to step S103.

  When it is determined that the image is appropriate, the scanning electron microscope 10 generates a line profile using the image (step S105).

  Specifically, the control module 131 uses the image to generate a line profile. The control module 131 also stores information in which the angle θ and the line profile are associated with each other in the storage device 122 as the line profile information 132.

  For example, in the case of the surface shape shown in FIG. 3A, the line profile shown in FIG. 3B is generated. Further, in the case of the surface shape as shown in FIG. 3C, a line profile as shown in FIG. 3D is generated. Note that FIG. 3A shows a state where the primary electron beam 112 is emitted at an angle θ of 0 degrees, and FIG. 3C shows a state where the primary electron beam 112 is emitted at an angle θ that is larger than 0 degrees.

  Further, the control module 131 tapers the range from the point where the increase rate of the signal strength becomes larger than the first threshold value to the point where the signal strength reaches the minimum value in the line profile. Calculate as width. The first threshold value is set in advance. When there are a plurality of ranges that satisfy the above definition, the largest range is calculated as the taper width.

  The range from the point where the signal strength is greater than the minimum value to the point where the decrease rate of the signal strength changes from the maximum value of the signal strength via the maximum value of the signal strength is equivalent to the taper width defined above. It is a range.

  In the related art such as Patent Document 1, the range from the minimum value to the maximum value is set as the taper width. However, when the primary electron beam 112 tilted with respect to the perpendicular of the surface of the sample 116 is irradiated, the line profile shown in FIG. 3D is generated. Although the maximum value on the right side can be defined in the line profile, there is also a maximum value near the maximum value. Depending on the conditions of the scanning electron microscope 10 and the sample 116, the relationship between the maximum value and the maximum value may be inverted due to the influence of charging on the sample surface, and the taper width may be mistaken in the conventional technique. Therefore, in the first embodiment, the measurement accuracy can be improved by considering the structure and setting the above range as the taper width.

  In Example 1, as shown in FIG. 3A, a taper that becomes thinner from the opening of the trench to the bottom is defined as a forward taper, and a taper that becomes thicker from the opening of the trench to the bottom is defined as an inverse taper. Further, as shown in FIG. 3A, the angle formed by the bottom surface and the side wall is defined as a taper angle. In the case of the forward taper, the taper angle is smaller than 90 degrees, and in the case of the reverse taper, the taper angle is larger than 90 degrees.

  Next, the scanning electron microscope 10 determines whether or not the characteristic amount A (θ) can be calculated (step S106).

  Specifically, the control module 131 determines whether or not there are two pieces of line profile information 132 having different angles θ. When it is determined that the two line profile information 132 having different angles θ do not exist, the control module 131 determines that the feature amount A (θ) cannot be calculated.

  When it is determined that the characteristic amount A (θ) cannot be calculated, the scanning electron microscope 10 returns to step S101 and executes the same processing.

  When it is determined that the characteristic amount A (θ) can be calculated, the scanning electron microscope 10 calculates the characteristic amount A (θ) (step S107).

  Specifically, the scanning electron microscope 10 calculates the characteristic amount A (θ) by substituting the taper widths Ta_1 and Ta_2 of the two line profiles into the equation (1). The feature amount A (θ) is a function having an angle as a variable.

  Ta_1 represents the taper width of the line profile whose angle θ is θ1, and Ta_2 represents the taper width of the line profile whose angle θ is θ2. Note that θ1 is larger than θ2.

  Here, the relationship between the feature amount A (θ) and the shape of the sample 116 will be described with reference to FIGS. 4A, 4B, and 4C.

  The absolute value of the angle at which the characteristic amount A (θ) becomes 0 or more corresponds to the taper angle of the trench. Further, the slope of the characteristic amount A (θ) represents the depth of the trench.

  When the shape of the trench of the sample 116 is a forward taper, the characteristic amount A (θ) is as shown in FIG. 4A. When the shape of the trench of the sample 116 does not form a taper, the characteristic amount A (θ) is as shown in FIG. 4B. When the shape of the trench of the sample 116 is an inverse taper, the characteristic amount A (θ) is as shown in FIG. 4C. As described above, when the trench has a reverse taper shape, the inclination angle has a positive value, and when the trench has a forward taper shape, the inclination angle has a negative value.

  Returning to the description of FIG.

  Next, the scanning electron microscope 10 determines whether the characteristic amount A (θ) is larger than a threshold value (second threshold value) (step S108). The process of step S108 is a process for determining whether the feature value A (θ) is a significant value. Note that the second threshold value is set in advance.

  When it is determined that the characteristic amount A (θ) is less than or equal to the second threshold value, the scanning electron microscope 10 returns to step S101 and executes the same processing. At this time, the control module 131 may delete the two line profile information 132 stored in the storage device 122, or may delete any one of the line profile information 132.

  When it is determined that the characteristic amount A (θ) is larger than the second threshold value, the scanning electron microscope 10 executes the analysis process (step S109). Details of the analysis process will be described with reference to FIG.

  Next, the scanning electron microscope 10 outputs the analysis result (step S110) and ends the process.

  Specifically, the control module 131 generates display information for displaying the analysis result, and outputs the display information to the output device 125.

  FIG. 5 is a flowchart illustrating an example of analysis processing executed by the scanning electron microscope 10 according to the first embodiment.

  The control module 131 calculates the depth w of the trench by substituting the feature quantities A (θ) and θ1 into the equation (2) (step S201).

  Next, the control module 131 calculates the taper angle using the feature values A (θ), θ1, and the trench depth w (step S202). Here, a method of calculating the taper angle will be described.

  As shown in FIGS. 4A, 4B, and 4C, the taper angle can be obtained as the absolute value of the intersection of the straight line with the inclination w and the axis of the angle as shown in Expression (3).

  Therefore, the control module 131 calculates the constant b by substituting the feature quantities A (θ), θ1 and the trench depth w into the equation (3). Further, the control module 131 calculates θ (tilt angle) at which A (θ) becomes 0 based on the equation (3), and calculates the absolute value as the taper angle.

  As described above, in the first embodiment, the taper angle can be calculated regardless of the difference in taper type. The above is the description of the calculation method of the taper angle.

  Next, the control module 131 determines whether the shape of the trench is a forward taper based on the inclination angle (step S203).

  Specifically, the control module 131 determines whether the tilt angle is smaller than 0 degree. When the taper angle is smaller than 0 degree, the control module 131 determines that the shape of the trench is a forward taper.

  When it is determined that the shape of the trench is a forward taper, the control module 131 proceeds to step S205.

  When it is determined that the shape of the trench is not a forward taper, the control module 131 determines whether the shape of the trench is an inverse taper based on the inclination angle (step S204).

  Specifically, the control module 131 determines whether the tilt angle is larger than 0 degree. When the taper angle is larger than 0 degree, the control module 131 determines that the shape of the trench is an inverse taper.

  When it is determined that the shape of the trench is an inverse taper, the control module 131 proceeds to step S205.

  When it is determined that the shape of the trench is not the reverse taper, that is, the trench does not have the taper, the control module 131 proceeds to step S205.

  In step S205, the control module 131 generates an analysis result (step S205). Then, the control module 131 ends the analysis process.

  For example, the control module 131 generates information including the taper angle, the taper width, and the taper type as the analysis result. The analysis result may include a line profile and an image.

  According to the first embodiment, the abnormality of the trench can be determined by using the two line profiles obtained by irradiating the primary electron beam 112 inclined with respect to the perpendicular of the surface of the sample 116.

  Since measurement of the sample 116 does not require work such as processing of the sample 116, improvement in process development efficiency and cost reduction can be realized. Moreover, since it is not necessary to acquire three or more images with different angles, the processing cost can be reduced.

  In the second embodiment, the abnormality of the side wall of the trench is determined by using the line profile obtained by irradiating the primary electron beam 112 inclined with respect to the perpendicular of the surface of the sample 116. Hereinafter, the second embodiment will be described focusing on the differences from the first embodiment.

  FIG. 6 is a diagram showing an example of the configuration of the scanning electron microscope 10 of the second embodiment.

  The scanning electron microscope 10 of the second embodiment includes an electron optical system lens barrel 101 and a control unit 102. The configuration of the electron optical system lens barrel 101 is the same as that of the first embodiment. The hardware configuration of the control unit 102 is the same as that of the first embodiment.

  In the second embodiment, the software configuration of the control unit 102 is partially different. Specifically, the storage device 122 holds the comparison line profile information 133.

  The comparative line profile information 133 is information for managing the line profile obtained from the sample 116 in which the sidewall of the trench is normal. The comparison line profile information 133 includes data in which an angle and a line profile are associated with each other. In the second embodiment, the line profile of the normal sample 116 is stored in advance as a comparison line profile.

  The comparison line profile may be generated based on the actual measurement result, or may be generated based on the result of the simulation.

  Other configurations are the same as those in the first embodiment.

  FIG. 7 is a flowchart illustrating an example of processing executed by the scanning electron microscope 10 according to the second embodiment.

  The processing of steps S101 to S105 and the processing of step S110 are the same as the processing described in the first embodiment.

  After the processing of step S105 is executed, the scanning electron microscope 10 executes the analysis processing (step S115). Details of the analysis process will be described with reference to FIG.

  FIG. 8 is a flowchart illustrating an example of analysis processing executed by the scanning electron microscope 10 according to the second embodiment. 9A, 9B, 9C, and 9D are diagrams showing the relationship between the shape of the sidewall of the trench and the line profile of the sample 116 of Example 2. 10A, 10B, and 10C are diagrams showing the characteristics of the line profile of the sample 116 having the notch of Example 2. 11A and 11B are diagrams illustrating an example of information included in the analysis result output by the scanning electron microscope 10 according to the second embodiment.

  The control module 131 compares the line profile of one line profile information 132 with the line profile of the comparison line profile information 133 (step S301).

  Specifically, the control module 131 refers to the comparison line profile information 133 and acquires the comparison line profile corresponding to the angle θ set in step S101. The control module 131 compares the acquired comparison line profile with the line profile generated in step S105.

  The control module 131 determines whether or not the shapes of the two line profiles are different (step S302).

  Here, the comparison of the shapes of the line profiles will be described.

  9A and 9C show an example of the sample 116. It should be noted that parts of the sample 116 having different materials are distinguished by using a pattern.

  9B and 9D show an example of a line profile. The line profile bar graph 901 represents the surface of the sample 116 irradiated with the primary electron beam 112.

  As shown in FIG. 9A, when the primary electron beam 112 is applied to the trench portion where the side wall has no notch, a line profile as shown in FIG. 9B is obtained. As shown in FIG. 9C, when the primary electron beam 112 is applied to the trench portion where the side wall has a notch, a line profile as shown in FIG. 9D is obtained.

  As shown in FIGS. 9B and 9D, the line profile obtained from the sample 116 in which the notch is present has a portion different from the line profile obtained from the normal sample 116.

  The control module 131 determines whether there is a different portion based on the comparison result of the two line profiles. If there is a different portion, the control module 131 determines that the shapes of the two line profiles are different. The difference in signal strength is not taken into consideration.

  When it is determined that the shapes of the two line profiles match, the control module 131 proceeds to step S304.

  When it is determined that the shapes of the two line profiles are different, the control module 131 calculates an index indicating the degree of abnormality (step S303). After that, the control module 131 proceeds to step S304.

  Here, the calculated index will be described with reference to FIGS. 10A, 10B, and 10C.

  10A, 10B, and 10C are enlarged views of the portion 902. The dotted line shows a line profile for comparison. As shown in the figure, the size of the difference from the comparison line profile differs depending on the size of the notch. That is, the larger the notch, the larger the extreme values of the shaded portion (area ABE) and the dotted portion (area ECD), and the larger the shaded portion and the dotted portion.

  Therefore, the control module 131 calculates the area of the shaded area or the distance between the CDs as an index. The above is the description of the index indicating the degree of abnormality.

  In step S304, the control module 131 generates an analysis result (step S304). Then, the control module 131 ends the analysis process.

  For example, the control module 131 generates information including the presence or absence of the notch and the index as the analysis result. The analysis result may include a line profile and an image. The analysis result including the graphs shown in FIGS. 11A and 11B may be output by executing the analysis process on a plurality of portions of the sample 116.

  FIG. 11A is a graph output when the shaded area is calculated as an index. Note that the sidewall abnormality degree is set based on the relative value of the size of the area and the like.

  By referring to the graph shown in FIG. 11A, the abnormality of the sidewall of the trench of the sample 116 can be grasped efficiently and with high accuracy. Further, it is possible to grasp the size of the abnormality on the side wall of the trench.

  FIG. 11B is a graph output when the distance between CDs is calculated as an index. The size of the side wall can be estimated by referring to the graph shown in FIG. 11B. This makes it possible to reduce the cost and time of process development.

  According to the second embodiment, by comparing the line profile obtained by irradiating the primary electron beam 112 inclined with respect to the perpendicular of the surface of the sample 116 with the comparative line profile, the sidewall of the trench of the sample 116 is abnormal. Can be determined.

  It should be noted that the present invention is not limited to the above-described embodiments, but includes various modifications. In addition, for example, the above-described embodiment is a detailed description of the configuration in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of each embodiment can be added, deleted, or replaced with another configuration.

  Further, the above-described respective configurations, functions, processing units, processing means, etc. may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. The present invention can also be realized by a program code of software that realizes the functions of the embodiments. In this case, the storage medium recording the program code is provided to the computer, and the processor included in the computer reads the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code itself and the storage medium storing the program code constitute the present invention. As a storage medium for supplying such a program code, for example, a flexible disk, a CD-ROM, a DVD-ROM, a hard disk, an SSD (Solid State Drive), an optical disk, a magneto-optical disk, a CD-R, a magnetic tape, A non-volatile memory card, ROM or the like is used.

  The program code that implements the functions described in this embodiment can be implemented in a wide range of programs or script languages such as assembler, C / C ++, perl, Shell, PHP, Python, and Java (registered trademark).

  Furthermore, by distributing the program code of the software that realizes the functions of the embodiments via a network, the program code is stored in a storage means such as a hard disk or a memory of a computer or a storage medium such as a CD-RW or a CD-R. Alternatively, the processor included in the computer may read and execute the program code stored in the storage unit or the storage medium.

  In the above-described embodiments, the control lines and information lines are shown to be necessary for explanation, and not all the control lines and information lines on the product are necessarily shown. All configurations may be connected to each other.

10 Scanning electron microscope 101 Electron optical system lens barrel 102 Control unit 111 Electron gun 112 Primary electron beam 113 Deflector 115 Objective lens 116 Sample 117 Sample holder 119 Detector 121 Computing device 122 Storage device 123 Scanning signal control device 124 Input device 125 Output Device 131 Control module 132 Line profile information 133 Line profile information for comparison

Claims (12)

A measuring device for irradiating a charged particle beam to measure the shape of a sample having an uneven portion,
A particle source for outputting the charged particle beam,
A lens for focusing the charged particle beam,
A detector for detecting a signal of emitted electrons emitted from the sample irradiated with the charged particle beam,
A control device for controlling the output of the charged particle beam and the detection of the signal of the emitted electron,
The control device is
By irradiating the sample with the charged particle beam at an arbitrary angle, a profile showing the relationship between the irradiation position and the intensity of the emitted electrons is generated,
Using the two profiles, perform an analysis process for analyzing the shape of the sample,
A measuring device which outputs the result of the analysis process. The measuring device according to claim 1, wherein
The control device is
Irradiating the sample with the charged particle beam at a first angle to generate a first profile,
Irradiating the sample with the charged particle beam at a second angle to generate a second profile,
In the first profile, the range from the point where the increase rate of the signal strength is larger than the first threshold value to the point where the signal strength reaches the minimum value via the maximum value of the signal strength is defined as the first taper width. Calculate,
In the second profile, the range from the point where the rate of increase of the signal strength is larger than the first threshold value to the point where the signal strength reaches the minimum value via the maximum value of the signal strength is the second taper width. Calculated as
Based on the first taper width and the second taper width, a feature amount related to the taper width and depth of the uneven portion is calculated,
Based on the feature amount, calculate the taper width and depth of the uneven portion,
A measuring device which outputs the result of the analysis process including the taper width and the depth of the uneven portion. The measuring device according to claim 2,
The control device is
Based on the feature amount, specify the type of taper of the uneven portion,
A measuring apparatus, which outputs a result of the analysis process including a taper type of the uneven portion. The measuring device according to claim 1, wherein
The control device is
Manages comparison profile information that stores comparison profiles that are associated with angles,
Irradiating the sample with the charged particle beam at a third angle to generate a third profile,
By comparing the third profile and the comparison profile associated with the third angle, it is determined whether or not there is an abnormality in the sidewall of the uneven portion,
A measuring apparatus, which outputs a result of the analysis processing including information regarding whether or not there is an abnormality on a sidewall of the uneven portion. The measuring device according to claim 4, wherein
The control device determines that there is an abnormality in the side wall of the uneven portion when the shape of the third profile is different from the shape of the comparison profile associated with the third angle. Measuring device. The measuring device according to claim 5,
The control device is
When it is determined that the side wall of the uneven portion has an abnormality, a value indicating a difference between the shape of the third profile and the shape of the comparison profile associated with the third angle is set to be a sidewall of the uneven portion. Calculated as an index showing the size of the abnormality of
A measuring device which outputs a result of the analysis process including the index. A method for measuring a sample, which is executed by a measuring device for irradiating a charged particle beam to measure the shape of a sample having an uneven portion,
A particle source for outputting the charged particle beam,
A lens for focusing the charged particle beam,
A detector for detecting a signal of emitted electrons emitted from the sample irradiated with the charged particle beam,
A controller for controlling the output of the charged particle beam and the detection of the signal of the emitted electron,
The measuring method of the sample is
A first step in which the control device irradiates the sample with the charged particle beam at an arbitrary angle to generate a profile indicating a relationship between an irradiation position and the intensity of the emitted electron;
A second step in which the control device executes an analysis process for analyzing the shape of the sample using the two profiles;
The control device includes a third step of outputting a result of the analysis processing, and a method of measuring a sample. The method of measuring a sample according to claim 7,
The first step is
The controller irradiating the sample with the charged particle beam at a first angle to generate a first profile;
Generating a second profile by irradiating the sample with the charged particle beam at a second angle.
The second step is
In the first profile, the control device determines a range from a point where the rate of increase of the signal strength is larger than a first threshold value to a point where the signal strength reaches the minimum value via the maximum value of the signal strength. Calculating as a taper width of 1;
In the second profile, the control device sets a range from a point where the rate of increase of the signal strength is larger than the first threshold value to a point where the signal strength reaches the minimum value via the maximum value of the signal strength. Calculating a second taper width,
A step in which the control device calculates a characteristic amount related to a taper width and a depth of the uneven portion based on the first taper width and the second taper width;
The controller includes a step of calculating a taper width and a depth of the uneven portion based on the characteristic amount,
The said 3rd step includes the step which the said control apparatus outputs the result of the said analysis process containing the taper width and depth of the said uneven | corrugated | grooved part, The measuring method of the sample characterized by the above-mentioned. The method of measuring a sample according to claim 8, wherein
The second step includes a step in which the control device specifies a taper type of the uneven portion based on the characteristic amount,
The said 3rd step includes the step which the said control apparatus outputs the result of the said analysis process containing the taper type of the said uneven | corrugated part, The measuring method of the sample characterized by the above-mentioned. The method of measuring a sample according to claim 7,
The control device manages comparison profile information that stores a comparison profile that is associated with an angle,
The first step includes a step of causing the control device to generate a third profile by irradiating the sample with the charged particle beam at a third angle,
In the second step, the control device determines whether or not there is an abnormality in a sidewall of the uneven portion by comparing the comparison profile and the third profile that are associated with the third angle. Including,
The said 3rd step includes the step which the said control apparatus outputs the result of the said analysis process containing the information regarding the presence or absence of abnormality of the side wall of the said uneven | corrugated part, The measuring method of the sample characterized by the above-mentioned. The method for measuring a sample according to claim 10, wherein
In the second step, when the shape of the third profile is different from the shape of the comparison profile associated with the third angle, the control device determines that the sidewall of the uneven portion has an abnormality. A method for measuring a sample, characterized by making a determination. The method for measuring a sample according to claim 11,
In the second step, when the control device determines that the sidewall of the uneven portion is abnormal, the shape of the third profile and the shape of the comparison profile associated with the third angle. Including a step of calculating a value indicating the difference as an index indicating the magnitude of abnormality of the side wall of the uneven portion,
The said 3rd step includes the step which the said control apparatus outputs the result of the said analysis process containing the said index, The measuring method of the sample characterized by the above-mentioned.

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