WO2015182224A1

WO2015182224A1 - Method and system for pattern dimension measurement using charged particle beam

Info

Publication number: WO2015182224A1
Application number: PCT/JP2015/058235
Authority: WO
Inventors: 慎弥村上; 宍戸　千絵; 田中　麻紀; 二大笹嶋; 仁生井
Original assignee: 株式会社日立ハイテクノロジーズ
Priority date: 2014-05-27
Filing date: 2015-03-19
Publication date: 2015-12-03
Also published as: TW201544791A

Abstract

In semiconductor-device production-process management using a CD-SEM, when a measurement position has been at the bottom of a hole pattern or groove pattern, the signal level from the bottom of the pattern has been relatively diminished as a result of pattern refinement and structural complexity, the pattern edge contrast of an obtained image has been insufficient, and visual confirmation and measurement of the measurement position has been difficult. In the present invention, the dimensions of a pattern including a hole or groove is measured through the setting of an area of the pattern including the hole or groove in an acquired charged particle beam image that is to have the dimensions thereof measured, the correction of the contrast of the charged particle beam image of the set area of the pattern including the hole or groove that is to have the dimensions thereof measured, and the processing of the image that has had the contrast thereof corrected.

Description

Pattern dimension measuring method and system using charged particle beam

The present invention relates to a pattern dimension measuring method using a charged particle beam that irradiates a pattern formed on a semiconductor wafer with a charged particle beam to acquire an image and measure the dimension, and a system thereof.

In the semiconductor manufacturing process, process control using a length measuring SEM, which is a scanning electron microscope (SEM) for dimension measurement, is performed on the dimensions of a pattern formed on a semiconductor wafer in recent years. The difficulty of dimensional measurement is increasing due to the miniaturization and complexity of devices. In particular, a deep hole (hereinafter referred to as Via) formed in a trench in a dual damascene process can be said to be a representative example. Via is small in size (diameter) and deeply formed, and has a high aspect ratio. When the inside of such a via hole is observed with a length measurement SEM, the amount of signal from the bottom of the via becomes small. . For this reason, the contrast of the Via bottom in the SEM image is insufficient, and there is a problem that it is difficult to visually confirm the measurement location of the Via on the SEM image, to set the measurement conditions, and to measure itself.

In contrast to a pattern image with insufficient contrast in a local region in an image obtained by SEM, Patent Document 1 uses a BSE (BackScattered Electron) image for region division to improve the contrast in the divided region. A process for improving the local contrast of a pattern image to be inspected is disclosed. Patent Document 2 discloses a pattern imaging method for setting a gain value which is an imaging condition for increasing the contrast in the ROI by setting an ROI (Region of Interest) on the pattern image.

Japanese Patent No. 5313939 JP 2002-319366 A

The present invention envisions a low-contrast measurement target that is difficult to visually check and measure edges, which occurs in a circuit pattern having a height difference formed on a semiconductor wafer.

Patent Document 1 is an invention intended to improve the contrast of a local region of a secondary electron image by performing contrast correction based on the result of region classification using a reflected electron image. However, in order to enhance the contrast of the bottom edge to be measured, it is necessary to extract a local area inside the pattern, and it is not sufficient to classify the area only by the reflected electron image.
In Patent Document 2, gain adjustment or gamma conversion is performed based on luminance information in a local area, but there is a detailed description of a local area extraction method inside a pattern and a contrast correction method by image processing. In other words, it is insufficient to enhance the contrast of the bottom edge of the measurement target.

In order to solve the above problems, in the present invention, a system for measuring the dimension of a pattern including a hole or groove formed on a sample using a charged particle beam is used as a pattern including a hole or groove formed on the sample. A charged particle beam image acquisition unit for acquiring a charged particle beam image of a pattern including holes or grooves by irradiating with charged particles and scanning the charged particle beam image acquired by the charged particle beam image acquisition unit A signal processing unit for measuring a dimension of a pattern including a hole or a groove, and a display unit having a screen for displaying a result processed by the signal processing unit. The signal processing unit is a charged particle beam image acquisition unit. Set in the measurement area setting unit that sets the pattern area including the holes or grooves whose dimensions are to be measured in the charged particle beam image acquired in step 1, and the measurement area setting unit And a contrast correction unit for correcting the contrast of the charged particle beam image in the pattern area including the hole or groove for measuring the measured dimension, and the signal processing unit processes the image whose contrast has been corrected by the signal processing unit. The dimensions of patterns including holes or grooves were measured.

In order to solve the above problems, in the present invention, a method for measuring the dimension of a pattern including a hole or groove formed on a sample using a charged particle beam is used. Irradiate and scan the pattern containing the charged particles to obtain a charged particle beam image of the pattern including the hole or groove, process the acquired charged particle beam image to measure the size of the pattern including the hole or groove, This includes displaying the processed results on the screen, and measuring the dimensions of the pattern including the holes or grooves, and setting the pattern area including the holes or grooves to measure the dimensions in the acquired charged particle beam image. , By correcting the contrast of the charged particle beam image in the pattern area including the hole or groove to measure the set dimension, and processing the image with the corrected contrast The dimensions of the pattern including the so measured.

Furthermore, in order to solve the above problems, in the present invention, a method for measuring a dimension of a pattern including a hole or a groove formed on a sample using a charged particle beam, a hole or a groove formed on the sample is measured. Irradiate and scan the pattern containing the charged particles to obtain a charged particle beam image of the pattern including the hole or groove, process the acquired charged particle beam image to measure the size of the pattern including the hole or groove, This includes displaying the processed result on the screen, and measuring the size of the pattern including the hole or groove, and displaying the acquired charged particle beam image and the contrast corrected image on the screen. Correct the contrast correction conditions of the image on the displayed screen, and measure the dimensions of the pattern including holes or grooves by processing the image with the corrected contrast under the corrected correction conditions. Was to so that.

The present invention improves the contrast of images of low-contrast measurement objects that are difficult to visually check for edges that occur in circuit patterns with different heights, especially hole bottoms and deep groove patterns, and has high reproducibility and high reliability. Enables setting of conditions and measurement.

1 is a block diagram showing a schematic configuration of a pattern dimension measuring system according to Embodiment 1 of the present invention. It is a figure which shows the SEM image of the pattern of the measuring object which concerns on Example 1 of this invention. It is sectional drawing (upper side) of the pattern of the measurement object which concerns on Example 1 of this invention, and the graph (lower side) which shows the luminance signal of the SEM image which the cross section can go. It is a flowchart which shows the flow of the process which performs the contrast correction | amendment inside the measurement pattern which concerns on Example 1 of this invention. It is a figure of the GUI screen for performing the measurement cursor setting which concerns on Example 1 of this invention. It is an enlarged view of the SEM image which shows the calculation method of the internal area | region of the measurement pattern which concerns on Example 1 of this invention. It is a graph which shows the change of the average brightness | luminance for every internal area | region of the measurement pattern which concerns on Example 1 of this invention. It is a graph which shows the tone curve used for the contrast correction which concerns on Example 1 of this invention. It is a graph which shows the change of the luminance value distribution of the SEM image by the difference in the inclination of the tone curve in the contrast correction which concerns on Example 1 of this invention. It is a figure of the GUI screen which displays the contrast correction result which concerns on Example 1 of this invention. It is a figure of the GUI screen which has the function of the parameter adjustment for contrast correction which concerns on Example 1 of this invention. It is a figure explaining the measurement process which concerns on Example 1 of this invention, and is the figure which displayed the measurement cursor and the dimension measurement point on the SEM image. It is a figure explaining the measurement process which concerns on Example 1 of this invention, and is a graph which shows the profile of the SEM image signal in the AB cross section of FIG. 9A. It is a figure explaining the measurement process which concerns on Example 1 of this invention, and is a figure of the SEM image which shows the state which set the bottom edge point of Via with the some horizontal straight line. It is a figure explaining the measurement process which concerns on Example 1 of this invention, and is a figure of the SEM image which shows the state which set the bottom edge point of Via by the some straight line which goes through the center of a pattern. It is a graph which shows the profile of the SEM image signal explaining the method of calculating a bottom edge by the threshold value method which concerns on Example 1 of this invention. It is a graph which shows the profile of the SEM image signal explaining the method of calculating a bottom edge by the linear method which concerns on Example 1 of this invention. It is a figure of the GUI screen for confirming the contrast correction image and measurement result which concern on Example 1 of this invention. It is a flowchart which shows the flow of the process which performs the contrast correction | amendment inside the measurement pattern using the design data which concerns on the modification 1 of Example 1 of this invention. It is a figure explaining the schematic area | region setting by the design data which concerns on the modification 1 of Example 1 of this invention, and is a figure which shows the image imaged by SEM. It is a figure explaining the schematic area | region setting by the design data which concerns on the modification 1 of Example 1 of this invention, and is a figure which shows the state which set the measurement cursor on design data. It is a figure explaining the schematic area | region setting by the design data which concerns on the modification 1 of Example 1 of this invention, and is a figure which shows the state which match | combined the position of the measurement cursor set on design data with the captured image. It is a flowchart which shows the flow of the process which performs contrast correction | amendment inside the measurement pattern using the point data which concern on the modification 2 of Example 1 of this invention. It is an enlarged view of the SEM image explaining the calculation method of the measurement pattern internal area | region using the bottom edge which concerns on the modification 3 of Example 1 of this invention. It is a figure explaining the calculation method of the measurement pattern internal area | region using the top edge which concerns on the modification 4 of Example 1 of this invention, and is a SEM image of a pattern. It is a figure explaining the calculation method of the measurement pattern internal area | region using the top edge which concerns on the modification 4 of Example 1 of this invention, It is a top edge image extracted by performing an edge extraction process from the SEM image of a pattern. It is a figure of the GUI screen which provides the function for switching the internal area | region calculation method which concerns on the modification 5 of Example 1 of this invention. It is a flowchart which shows the flow of a process of the measurement recipe installation which concerns on the modification 6 of Example 1 of this invention. It is the graph (lower side) which shows the SEM image (upper side) of the trench pattern which concerns on the modification 7 of Example 1 of this invention, and the profile of the SEM image signal in this cross section. It is a graph (lower side) which shows the SEM image (upper side) of the groove pattern which concerns on the modification 8 of Example 1 of this invention, and the profile of the SEM image signal in this groove pattern. SEM (upper side) in a state where brightness contrast correction is performed on the SEM image of the groove pattern according to the modified example 8 of Example 1 of the present invention, and a graph showing the profile of the SEM image signal in this groove pattern (lower side) It is. It is a block diagram which shows the schematic structure of the pattern dimension measurement system which concerns on Example 2 of this invention. It is a flowchart which shows the flow of the process which performs contrast correction | amendment inside the measurement pattern which concerns on Example 2 of this invention. It is sectional drawing of the sample in which the hole pattern which shows the emission direction of the electron generated in the bottom of the Via-in Trench pattern (deep hole pattern) based on Example 2 of this invention was formed. It is a histogram which shows distribution of the luminance value of the upper detection image by the electron which generate | occur | produced at the bottom of the Via-in Trench pattern (deep hole pattern) which concerns on Example 2 of this invention. It is a histogram which shows distribution of the luminance value of the oblique detection image by the electron which generate | occur | produced in the bottom of the Via-in Trench pattern (deep hole pattern) which concerns on Example 2 of this invention. It is a block diagram which shows the schematic structure of another example of the pattern dimension measuring system which concerns on Example 2 of this invention. It is a figure of the GUI screen for performing the contrast correction parameter setting by the preset which concerns on the modification of Example 2 of this invention.

The present invention can extract an inner region of a hole or groove pattern in a charged particle beam image acquired by a scanning electron microscope (SEM), and can visually recognize the edge of the hole or groove pattern based on the luminance information of the extracted inner region. In this way, the contrast of the charged particle beam image is corrected and displayed, and the dimension of the hole or groove pattern can be accurately measured using the image with the corrected contrast.
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In this example, a circuit pattern with a height difference formed on a semiconductor wafer, in particular, a trench (deep groove) or via (deep hole), or a pattern called Via-in-Trench in which Via exists in the trench is obtained by SEM. The present invention relates to a system for improving visibility inside a pattern in an image obtained by imaging.

Hereinafter, an embodiment when applied to a pattern dimension measuring apparatus (length measuring SEM) using an SEM will be described with reference to the drawings.

FIG. 1 shows an overall configuration diagram of an apparatus for realizing a pattern dimension measurement system according to the present embodiment. The length measuring SEM 100 according to the present embodiment is configured to include a SEM main body 120 and a signal processing system 130.

The SEM main body 120 includes an XY stage 107 on which a silicon wafer (sample) 106 on which a circuit pattern to be measured is formed, an irradiation optical system 140 for controlling the electron beam 101 emitted from the electron gun 102, and emitted from above the sample. The detector 108 for detecting the electrons to be detected is provided. The irradiation optical system 140 includes an electron gun 102, a condenser lens 103, a deflector 104, and an objective lens 105 on the path of the electron beam 101.

The signal processing system 130 for the detection signal includes an A / D converter 109 that converts an analog signal output from the detector 108 that has detected secondary electrons generated from the sample 106 irradiated with the electron beam 101 into a digital signal, and A Controls the CPU 113, the LSI 114, the arithmetic unit 110 having the image memory 115, and the arithmetic unit 110, which input and processes the signal converted by the / D converter 109, and the SEM main body 120 via the arithmetic unit 110. A terminal 111 and a storage terminal 112 for storing data are provided.

The electron beam 101 emitted from the electron gun 102 is irradiated onto the silicon wafer 106 under the control of the condenser lens 103, the deflector 104, and the objective lens 105 of the irradiation optical system 140. Secondary electrons are emitted from the region irradiated with the electron beam 101 on the silicon wafer 106, and a part thereof is incident on the detector 108 and detected. An analog signal output from the detector 108 that has detected secondary electrons is converted into a digital signal by the A / D converter 109 and input to the arithmetic unit 110.

The calculation unit 110 receives the signal data from the detector 108 converted into a digital signal by the A / D converter 109 and stores the signal data in the image memory 115. In addition, it also has a function as an observation image acquisition unit that generates a detection electronic image based on the result detected by the detector 108.

A CPU (Central Processing Unit) 113, an LSI 114 storing image processing software, etc. execute image processing according to the purpose of dimension measurement, and measure the dimension of the pattern. The data stored in the image memory 115 may be stored again in the external storage device 112.

The control terminal 111 controls the coordinates of the XY stage 107 and the measurement sequence via the calculation unit 110.
The control terminal 111 has a GUI (Graphical User Interface) that displays an observation image, a dimensional measurement result, and the like on the screen 116 for the user. The user can change the coordinates of the pattern on the silicon wafer and the pattern required for the dimensional measurement. Imaging recipe data including a pattern matching template used for positioning, imaging conditions, and the like can be created.

FIG. 2A is a pattern image 201 showing an example of a so-called Via-in-Trench structure in which a Via pattern that is a deep hole pattern is formed on the bottom surface of a trench pattern on a silicon wafer 106 to be measured as an example of a measurement target. It is. Reference numeral 204 denotes a mask region on the

silicon wafer

106, 205 denotes a trench formed by removing a part of the

mask region

204, and 206 denotes a hole (Via) processed in the trench 205.

2B shows a cross-sectional structure 202 corresponding to the straight line 207 between point A and point B in the pattern image 201 in FIG. 2A and the luminance profile 203 acquired from the pattern image 201 in the region on the straight line 207. In the cross-sectional structure 202, the mask 208, the trench bottom 209, and the Via bottom 210 are arranged in this order from the top, and the side wall 211 is tapered. The measurement target includes the top edge interval 212 and the bottom edge interval 213.

In the luminance profile 203, the horizontal axis represents the position on the sample, and the vertical axis represents the luminance of the detection signal. The measurement of the top edge interval 212 of the via 206 formed on the bottom surface 209 of the trench 205 from the luminance profile 203 can be performed relatively easily because the luminance of the top edge 215 is sufficiently obtained. However, in the measurement of the bottom edge interval 213 of the bottom surface 210 of the Via 206, the luminance range 214 corresponding to the side wall 211 is very small and dark, so that the user cannot determine whether the measurement is properly performed from the measurement result. Occurs.

FIG. 3 is an operation flow of the pattern dimension measurement system according to the first embodiment of the present invention. Hereinafter, a specific processing method for the steps in FIG. 3 will be described.

First, in step S301, an image of a pattern on a silicon wafer is taken by the length measuring SEM 100 in FIG. An image obtained at this time is 201 in FIG.
In step S 302, the calculation unit 110 displays the captured image 201 in FIG. 2A on the GUI of the control terminal 111.
In step S303, the user sets a measurement cursor on the measurement target pattern by operating the mouse on the image 201 in FIG. 2A of the GUI displayed on the display screen 116 in the control terminal 111. This is a pattern outline. This is an area. (Details of this step will be described in FIG. 4)
In step S304, the calculation unit 110 reduces the cursor, which is a schematic area set on the GUI, and calculates an internal area of the pattern. (Details of this step are explained in FIG. 5)
In step S305, the calculation unit 110 calculates a luminance range within the reduced cursor area.
In step S306, the calculation unit 110 performs contrast correction by contrast correction processing that increases the luminance range obtained in step S305. (Details of this step are explained in FIG. 6)
In step S 307, the calculation unit 110 displays the images before and after contrast correction and the intermediate processed image on the GUI in the control terminal 111. (Details of the GUI in this step will be described in FIG. 7)
In step S308, if the user wants to correct the correction result, the user proceeds to contrast correction parameter adjustment in step S309, and adjusts the contrast correction parameter. If there is no problem, the process proceeds to step S310.
In step S309, the user adjusts the contrast correction parameter on the GUI. After parameter adjustment, the process returns to step S306 (details of parameter adjustment will be described with reference to FIG. 20).
In subsequent step S310, measurement is performed using the image after contrast correction and the measurement cursor input in step S303.

FIG. 4 is a diagram showing a GUI for performing measurement cursor setting in step S303 of FIG. A captured image 402 is displayed on the GUI screen 401. The user operates the mouse cursor 403 and drags the mouse cursor 403 from, for example, a point 404 to a point 405 to set a rectangular area 406 including the via 206 to be measured inside the trench 205 as a measurement cursor. This measurement cursor can be registered by moving and clicking. The registered measurement cursor can also be corrected by moving the mouse cursor 403 to the reset button 408 and clicking.

FIG. 5A is a diagram showing a method for calculating the internal area of the pattern in step S304 of FIG. The image 501 is an enlarged view of the vicinity of the measurement cursor 506 (corresponding to the measurement cursor 406 described in FIG. 4) set in step S303 in the pattern image 201 shown in FIG. 2A. The

measurement cursors

507, 508, and 509 are areas obtained by reducing the area surrounding the measurement cursor 506 in order at the same ratio.

5B is a graph 510 in which the average luminance in each region from the measurement cursors 506 to 509 is plotted as the vertical axis, and the number of times the cursor is reduced as the points 506p to 509p along the horizontal axis. When the change in the average brightness becomes small, the cursor in front of which the change becomes small is set as the internal area 502 of the Via 206. As the surrounding area of the measurement cursors 506 to 508 is reduced, the bright area of the mask 503, the trench 504, and the top edge 505 of the Via 206 included in the measurement cursor is decreased, and the ratio of the dark area that is the internal area 502 of the Via 206 is occupied. Therefore, the average luminance greatly decreases as indicated by plot points 506p to 508p.

The measurement cursor 508 and the cursor 509 both include the entire measurement cursor in the internal area 502 of the Via 206. Since the contrast of the internal region 502 of the Via 206 is low, the change in average luminance in the measurement cursor is small as indicated by

plot points

508p and 509p. Thereby, the measurement cursor 508 is applied as the internal region 502 of the Via 206.

6A and 6B are diagrams showing the contrast correction method in step S306 of FIG. The contrast correction is processed using the tone curve 601 shown in FIG. 6A. The x-axis of the tone curve 601 is an input luminance value, and the y-axis is an output luminance value after conversion, both of which are expressed in 256 gradations. The tone curve 601 includes a minimum brightness value x _min and a maximum brightness value x _max of the inner area 502 of the via 206 acquired using the measurement cursor 508 in step S305, and a contrast enhancement level slider value r input in step S309 described later. The offset slider value b is used to obtain the output values y _min and y _max of x _min and x _max after contrast correction.

The output luminance values y _min and y _max can be calculated by the following (Equation 1) and (Equation 2).

R is expressed by the following (Equation 3).

r is a parameter for adjusting the ratio of the size of the input luminance range (x _max -x _min ) to the size of the output luminance range (y _max -y _min ) (the slopes of the

line segments

606, 607, and 608 in FIG. 6A). It becomes. b is a parameter for adjusting the offset of the output luminance of the internal region 502 (y intercept of the

line segments

607 and 608 in FIG. 6A). At the brightness near the upper and lower limits of the dynamic range of the image, the sensitivity of human vision to the difference in brightness may be small, and even if there is a sufficient brightness difference on the image, it may be difficult to view. Therefore, by adjusting the offset parameter, the pixel value inside the pattern can be output to a luminance value that is easy for humans to visually recognize.

Was determined by the above, the point (x _{_min,} y _min), a point (x _{_max,} y _max) constitutes a tone curve 601 at

segment

606, 607 and 608 connecting the. Further, the tone curve may be composed of a smooth curve such as a Bezier curve in addition to the line segment.

FIG. 6B shows a profile 602 around the region of Via 206 in the image 201 which is the original image. The horizontal axis indicates the position, and the vertical axis indicates the luminance value. 609 is a trench, 610 is a top edge of the

Via

206, 611 is a side wall of the

Via

206, and 612 is a luminance value of a secondary electron detection signal from a portion corresponding to the bottom surface of the Via 206. The input luminance range 613 is a range including the bottom surface of the via 206 and the side wall of the via 206.

By correcting the profile 602 with the tone curve 601 in FIG. 6A, a profile 603 as shown on the lower side of FIG. 6B is obtained. As a result, the input luminance range 613 extends to the output luminance range 614, and the contrast between the bottom surface 210 of the via 206 and the image on the side wall 211 can be enhanced.

FIG. 7 is a diagram showing a GUI for displaying the image after the contrast correction in step S307 in FIG. On the GUI screen 701, a captured original image 702 including the images of the trench 205 and Via 206 (corresponding to the pattern image 201 in FIG. 2A), a mask region 7031 with corrected contrast, and a contrast corrected image 703 including images of the trench 7032 and Via 7033 are displayed. Is displayed.

Also, a measurement area information image 704 indicating the setting area of the measurement cursor 406 set in step S303 and an internal area information image 705 indicating the setting area of the pattern internal area measurement cursor 508 calculated in step S304 are displayed as intermediate results.

The user confirms the contrast correction image 703, and if the correction of the contrast correction parameter is necessary, the user clicks the correction button 711 and proceeds to step S309. If it is not necessary to correct the contrast correction parameter, the user clicks the OK button 712 and proceeds to step S310.

FIG. 8 is a diagram showing a GUI for performing the contrast correction parameter adjustment in step S309 of FIG. In the GUI 801, the user operates a contrast enhancement level slider 802 that adjusts the degree of strength of contrast correction and an offset slider 803 that adjusts the luminance offset of a region in which contrast is enhanced on the GUI 801, and presses a setting button 804. You can input parameters with. The input parameters are used in step S306 as a contrast enhancement level slider value r and an offset slider value b. However, in the first step S306, the contrast enhancement level slider value r and the offset slider value b use preset initial values.

Although an example in which the screen for displaying the image after contrast correction in FIG. 7 and the screen for adjusting the contrast correction parameter in FIG. 8 are separately displayed has been shown, these screens should be displayed simultaneously on the same screen. May be. By displaying these screens simultaneously on the same screen, the contrast can be adjusted more efficiently.

FIG. 9A is a diagram showing a measurement method in the measurement process of step S310 of FIG. The pattern image 901 is an image obtained by enlarging the area displayed on the contrast-corrected image 703 corresponding to the area surrounded by the measurement cursor 406 displayed on the measurement area information display unit 704 in FIG.

A case will be described in which a bottom edge that is a measurement target is detected for the pattern image 901. A line segment 904 is set in the measurement cursor 903 (corresponding to the measurement cursor 406 in FIG. 4 and the measurement cursor 506 in FIG. 5) set in step S303, and the image signal on the line segment 904 is displayed as shown in FIG. 9B. The profile 902 is acquired.

Since the contrast corresponding to the side wall of the profile 902 is sufficiently enhanced by the contrast correction processing, the point 905 in FIG. 9A and the linear method described in FIG. The bottom edge points 905p and 906p corresponding to the point 906 can be easily calculated.

These bottom edge points are converted into a plurality of horizontal straight lines 9071 to 9075 as indicated by dotted lines in the image 907 in FIG. 9C, or straight lines 9081 to 9081 in each direction passing through the center of the pattern as indicated by dotted lines in the image 908 in FIG. 9D. A plurality of 9084 profiles are obtained, and an average value of distances between edge points on each straight line (for example, a distance between points 905p and 906p in FIG. 9B) is used as a measurement value.

The user can confirm whether or not the measurement is correctly performed by confirming the calculated plurality of bottom edge points on the pattern image 901 after the contrast correction.

FIG. 10A is a diagram showing a threshold method for calculating the edge position from the luminance profile, and FIG. 10B is a diagram showing a linear method for calculating the edge position from the luminance profile.

The edge calculation method by the threshold method in FIG. 10A is based on a profile defined by a threshold 1005 by percentage when the maximum peak 1003 of the profile is 100% and the minimum peak 1004 is 0% with respect to the luminance profile 1001. The point 1006 is the edge.

On the other hand, in the edge calculation method by the linear method of FIG. 10B, the position of the intersection 1009 of the straight line 1007 that touches the luminance profile 1002 at the point where the profile slope is maximum and the straight line 1008 that touches the minimum peak of the profile is the edge.

FIG. 11 is a diagram showing a GUI for displaying measurement results and image quality improvement results used when setting measurement parameters in step S310. On the GUI screen 1101, measurement points that are measurement results are displayed on the contrast-corrected image 1102. 1103 is displayed in an overlapping manner. Thereby, the user can compare the image quality improvement result and the measurement result, and can easily confirm whether the measurement is performed correctly. Check

boxes

1104 and 1105 can be used to switch between an image measurement result before contrast correction and an image measurement result after contrast correction processing.

According to the present embodiment, in the SEM image of the Via-in-Trench pattern, the contrast inside the Via that is a deep hole can be improved to the extent that it can be easily visually confirmed, so that the measurement is correctly performed. And measurement conditions can be set easily and accurately, and measurement can be performed more accurately.

[Modification 1]
As a first modification of the first embodiment, a method of extracting a region inside the pattern by using the design data of the semiconductor pattern for the measurement cursor setting in S303 of the processing flow diagram of FIG. 3 described in the first embodiment will be described. .

FIG. 12 is an operation flow of the pattern dimension measurement system according to the first modification. Hereinafter, a specific processing method for the steps in FIG. 12 will be described.

First, in step S1201, an image of a pattern on a silicon wafer is taken by the length measuring SEM 100.
In step S 1202, the calculation unit 110 displays the captured image on the GUI of the control terminal 111.
In step S1203, the calculation unit 110 reads design data having the same coordinates as the captured image from the storage device 112.
In step S1204, the arithmetic unit 110 aligns the captured image and the design data, and calculates a schematic region (measurement cursor setting region) of the measurement target pattern from the design data after the alignment. (Details of this step will be described in FIG. 14)
Thereafter, the steps after step S304 in FIG. 3 are processed.

FIGS. 13A to 13C are diagrams showing the alignment of the design data in step S1204 of FIG. FIG. 13A is a captured image 1301 obtained by imaging the Via-in-Trench formed on the semiconductor wafer 106 as a sample with the SEM 120.

FIG. 13B shows a measurement cursor area 1302 set from design data in the Via pattern layer stored in the storage device 112. Since a positional deviation occurs between the captured image 1301 and the design data 1302, a measurement cursor area 1303 on the design data is set as shown in FIG. 13C in which the positional deviation is corrected by pattern matching. A measurement cursor area 1303 on the design data in which the positional deviation is corrected is used as the approximate area of Via.

According to the present embodiment, since the schematic area setting of the pattern can be automatically performed by using the design data, the burden of the user's setting operation can be reduced as compared with the case of the first embodiment.

[Modification 2]
In this modification, the measurement cursor setting in step S303 of the processing flow diagram of FIG. 3 described in the first embodiment is not performed using a rectangular cursor, but using the point data input by the user as the center point of the pattern. A case where region extraction is performed will be described.

FIG. 14 is an operation flow of the pattern dimension measurement system according to the second modification. Hereinafter, a specific processing method for the steps in FIG. 14 will be described.

First, in step S1401, an image of a pattern on a silicon wafer is taken by the length measuring SEM 100.
In step S 1402, the calculation unit 110 displays the captured image on the GUI of the control terminal 111.
In step S1403, the user sets the center position of the measurement pattern as point data by operating the mouse in the captured image displayed on the GUI in the control terminal 111.
In step S1404, the calculation unit 110 arranges an elliptical approximate area centered on the point data, obtains the average average brightness while enlarging the elliptical area according to the same principle as in FIG. 5, and when the change in average brightness becomes small Is calculated as an inner region.
Thereafter, the steps after step S305 in FIG. 3 are processed.

In the calculation of the pattern inner area in step S1404, the inside of the ellipse centered on the coordinates of the point data is calculated as the inner area of the pattern using fixed parameters set in advance for the major axis and minor axis.

In this embodiment, the input operation on the GUI is reduced by using the point data, so that the burden of the user's setting operation can be reduced as compared with the first embodiment.

[Modification 3]
As another method of calculating the pattern internal area in step S304 of the first embodiment, the bottom edge vicinity area shown in FIG. 15 is used in this modification. For the pattern image 1501, bottom edge detection similar to the method shown in the image 908 of FIG. 9 described in the first embodiment is performed, and a bottom edge point 1502 in the approximate region is calculated. A circular area 1503 centered on the bottom edge point is obtained, and this area is set as an internal area of the pattern.

According to the present embodiment, since the luminance range in the region near the bottom edge to be measured can be obtained, contrast correction near the bottom edge can be effectively performed.

[Modification 4]
In the present modification, the pattern inner area calculation in step S304 of the first embodiment and the pattern inner area calculation in step S1404 in the second modification are secondarily performed at a position where the pattern cross section as shown by 215 in FIG. The calculation is made by using the top edge that becomes bright because many electrons are emitted.

FIG. 16 is a diagram showing a method for calculating the pattern internal region using the top edge. A top edge image 1602 in the approximate area 1605 is calculated for the pattern image 1601 using edge detection processing. A closed region 1604 surrounded by the top edge 1603 is set as an internal region of the pattern.

This embodiment can extract an internal region along the pattern shape, and is effective in calculating a sufficiently large internal region for obtaining luminance information when the pattern to be measured is small.

[Modification 5]
In this modification, the pattern approximate area setting method in the first embodiment and the first and second modification examples and the pattern internal area calculation method in the first and third modification examples are used in any combination. In the present modification, the calculation unit 110 in FIG. 1 holds all the internal area calculation methods in the first embodiment and the third and fourth modifications as functions, and the internal area calculation is performed by the internal area setting method selection GUI 1700 shown in FIG. The user can select the method.

This modification allows the user to select an effective internal area setting method according to the measurement pattern.

[Modification 6]
In this modification, a measurement recipe including contrast correction processing is set, and automatic measurement is performed using the saved recipe data.

FIG. 18 is a diagram illustrating a measurement recipe setting flow used when automatic measurement is performed. Hereinafter, the processing method of the step of FIG. 18 will be described.
In step S1801, the wafer to be measured is loaded into the apparatus.
In step S1802, measurement target wafer information such as chip size and chip arrangement is input.
In step S1803, a wafer alignment point used for matching for correcting a shift during movement of the XY stage is registered.
In step S1804, registration of measurement points, setting of FOV (Field of View), and registration of addressing points used for matching for correcting displacement due to beam shift are performed.
In step S1805, an image of the measurement point after the contrast correction at the measurement point is acquired by performing the processing of steps S302 to S310 in FIG.

In step S1806, a measurement method and measurement parameters are set using the contrast-corrected image.
In step S1807, the parameters set in steps S1802, S1803, S1804, and S1806 and the contrast correction parameters set in the flow of FIG. 3 are stored as recipe data.
Using the stored recipe, automatic measurement is performed on another chip on the same wafer or a patterned wafer having the same design.

According to the present embodiment, by including the contrast correction parameter in the recipe data, it is possible to perform the measurement by performing the contrast correction even in the automatic measurement.

[Modification 7]
This modification is applied when the difference between the brightness of the image of the trench portion and the brightness of the image of the bottom portion of the Via is small. FIG. 2219 shows an example of a pattern acquired with the same brightness of the trench and the Via in the Via-in-Trench structure of the first embodiment.

When the trench depth 1903 is sufficiently larger than the portion 1904 between the trench bottom 1905 and the Via bottom 1906 in the pattern cross section 1901 in the upper diagram, the brightness 1907 of the trench portion as shown in the luminance profile 1902 of the lower graph. And the brightness 1908 at the bottom of the Via are very small relative to the overall brightness range.

In such a pattern, in order to improve the contrast of both the trench and via regions, the region inside both the trench and via regions may be extracted to perform local contrast correction.

This makes it possible to obtain an output image with improved contrast both inside the via and inside the trench.

[Modification 8]
This modification is an example that can be applied to the case where the bottom edge of the groove pattern is a measurement target. FIG. 20A is a diagram illustrating an example in which the bottom edge of the groove pattern is a measurement target. In the brightness profile 2003 of the groove pattern image 2001, the contrast of the side wall profile 2006 is very low, so that it is difficult to visually recognize 2005 between the bottom edges.

On the other hand, an image 2002 shown in FIG. 20B is an image according to this modification, and is an image obtained by extracting the inner region of the groove by the flow of FIG. 3 and performing local contrast correction.

In the brightness profile 2004 of the image 2002 after contrast correction, the brightness range of the side wall profile 2007 is widened, so that the 2008 between the bottom edges can be easily visually recognized.

In the first embodiment, the method of extracting the region inside the pattern using the sample image acquired by the length measuring SEM 100 has been described. In the second embodiment, the image is picked up by a detector different from the pattern image to be measured. A case will be described in which an area inside a pattern is extracted using the pattern image thus obtained.

FIG. 21 shows an overall configuration diagram of an apparatus for realizing a pattern dimension measurement system according to the second embodiment. A length measurement SEM 2100 according to the present embodiment includes a SEM body 2120 and a signal processing system 2130. In addition, the same number is attached | subjected to the thing of the same structure as length measurement SEM100 demonstrated in FIG.

The SEM main body 2120 includes an XY stage 107 on which a silicon wafer (sample) 106 on which a circuit pattern to be measured is formed, an irradiation optical system 2140 for controlling the electron beam 101 emitted from the electron gun 102, and an angle with respect to the sample. Reflector 2102 that receives electrons emitted in the direction, oblique detector 2103 that detects secondary electrons emitted from the reflector 2102, reflector 2101 that receives electrons emitted in a direction substantially perpendicular to the sample, reflector An upper detector 2104 for detecting secondary electrons emitted from 2101 is provided. The irradiation optical system 2140 includes an electron gun 102, a condenser lens 103, a deflector 104, and an objective lens 105 on the path of the electron beam 101.

A signal processing system 2130 for detection signals converts an analog signal output from the oblique detector 2103 into a digital signal, an A / D converter 2105, and converts an analog signal output from the upper detector 2104 into a digital signal A. The CPU 2113, the LSI 2114, and the image memory 2115, each of which receives and processes the signals converted by the A / D converter 2106, A /

D converters

2105 and 2106, respectively, and controls the arithmetic unit 2110 and the arithmetic unit 2110 A control terminal 2111 for controlling the SEM 2120 and a storage terminal 2112 for storing data.

In such a configuration, the electron beam 101 emitted from the electron gun 102 is controlled by the condenser lens 103, the deflector 104, and the objective lens 105 of the illumination optical system 2140, and irradiated onto the silicon wafer 106. Electrons are emitted from the region irradiated with the electron beam 101 on the silicon wafer 106. At this time, electrons emitted in an oblique direction with respect to the silicon wafer 106 collide with the reflection plate 2102, emit secondary electrons, and are detected by the oblique detector 2103.

Further, the electrons emitted in the substantially vertical direction with respect to the silicon wafer 106 collide with the reflection plate 2101, emit secondary electrons, and are detected by the upper detector 2104. The electrons detected by the oblique detector 2103 are converted into digital signals by the A / D converter 2105, and the electrons detected by the upper detector 2104 are converted into digital signals by the A / D converter 2106, respectively. Entered.

The calculation unit 2110 receives the detection results of the

detectors

2103 and 2104 converted into digital signals, and stores the detection results in the image memory 2115. In addition, it also has a function as an observation image acquisition unit that generates a detection electronic image based on the detection results of the

detectors

2103 and 2104.

A CPU (Central Processing Unit) 2113, an LSI 2114 storing image processing software, etc. execute image processing according to the purpose of dimension measurement, and measure the dimension of the pattern. The data stored in the image memory 2115 may be stored again in the external storage device 2112.

The control terminal 2111 controls the coordinates of the XY stage 107 and the measurement sequence via the calculation unit 2110.

The control terminal 2111 has a GUI (Graphical User Interface) for displaying an observation image, a dimension measurement result, and the like on the screen 2116 for the user. The user can coordinate the pattern on the silicon wafer and the pattern required for the dimension measurement. Imaging recipe data including a pattern matching template used for positioning, imaging conditions, and the like can be created.

Also, the control terminal 2111 creates imaging recipe data including pattern coordinates on the silicon wafer 106 required for dimension measurement, a pattern matching template used for pattern positioning, imaging conditions, and the like.

FIG. 22 is an operation flow of the pattern dimension measurement system according to the second embodiment. Hereinafter, a specific processing method for the steps of FIG. 22 will be described.
First, in step S2201, an upper detection image by the upper detector on the silicon wafer and an oblique detection image by the oblique detector are acquired by the length measurement SEM 2100.
In step S2202, the calculation unit 2110 displays the upper detection image and the oblique detection image on the GUI of the control terminal 2111.
In step S2203, the calculation unit 2110 extracts a dark area from the oblique detection image, and sets this as a schematic area of the pattern. (Details of this step will be described with reference to FIG. 1123)
In step S2204, the calculation unit 2110 calculates the inner area while changing the size of the approximate area of the upper detection image (the details of this step are the processing in step S304 of the flowchart of FIG. 3 described in the first embodiment). That is, it is the same as the processing described with reference to FIG.
In step S2205, the calculation unit 2110 calculates a luminance range in the inner region of the upper detection image.
In step S2206, the calculation unit 2110 corrects the contrast of the upper detection image by contrast correction processing that increases the luminance range obtained in step S2205. (This step is the same as FIG. 6)
In step S 2207, the calculation unit 2110 displays the upper detection image after contrast correction on the GUI in the control terminal 2111.
In step S2208, the user confirms the contrast correction image displayed on the GUI of the control terminal 2111. If the user wants to correct the correction result, the process proceeds to contrast correction parameter setting in step S2209. If there is no problem, the process proceeds to step S2210.
In step S2209, the user sets the contrast correction parameters in the method described with reference to FIG. 8 in the first embodiment, that is, in the GUI 801, the contrast enhancement level slider 802 for adjusting the degree of contrast correction strength, and the contrast. The user can input parameters by operating the offset slider 803 on the GUI 801 for adjusting the luminance offset of the region where the emphasis is emphasized and pressing the setting button 804.

The input parameters are used in step S2206 as a contrast enhancement level slider value r and an offset slider value b. However, in the first step S2206, the contrast enhancement level slider value r and the offset slider value b use preset initial values.
After setting the parameters, the process returns to step S2206 and re-executes up to S2208.
In step S2210, measurement is performed on the image after contrast correction.

FIG. 23A to FIG. 23C are diagrams showing the extraction of the dark area by the oblique detection image in step S2203 of FIG. Of the electrons 2305 to 2309 emitted from the hole bottom 2311 when the electron beam 101 emitted from the electron gun 102 is irradiated to the pattern 2301 formed on the

silicon wafer

106, 2305 and 2309 collide with the side wall 2312 of the pattern 2301, and are not detected.

Electrons

2306 and 2308 are obliquely emitted from the holes and collide with the reflector 2102 in FIG. 21, and secondary electrons incident on the oblique detector 2103 among the secondary electrons generated from the reflector 2102 due to the collision are detected. The The electrons 2307 are emitted almost vertically from the hole and collide with the reflector 2101 in FIG. Of the secondary electrons generated from the reflector 2101 due to this collision, the secondary electrons incident on the upper detector 2104 are detected by the upper detector 2104.

Since the number of electrons coming from an angle is highly correlated with the aspect ratio of the hole shape (ratio of hole depth to hole size), the oblique detection image clearly shows the brightness and darkness according to the area of each pattern. Become an image. On the other hand, since the number of electrons that appear vertically is small, the upper detection image is noisy, but a signal is returned from the deep hole bottom, so it is used to measure and inspect the hole bottom pattern.

The histogram 2302 of the upper detection image and the histogram 2303 of the oblique detection image obtained from the Via-in-Trench pattern are shown. In each histogram, 2310u and 2310t are distributions of Via regions, 2311u and 2311t are distributions of trench regions, and 2312u and 2312t are distributions of mask regions. Since the histogram 2302 of the upper detection image has a lot of noise, the distributions of the respective regions are overlapped, and the region division is difficult. On the other hand, since the diagonal detection image histogram 2303 has a high S / N, the distribution of the histogram of each region can be easily divided into regions by performing threshold processing on the oblique detection image.

According to the present embodiment, since the outline area setting of the pattern can be automatically performed by using the oblique detection image, the burden of the user's setting operation can be reduced as compared with the first embodiment.

Further, instead of the length measurement SEM 2100 of FIG. 21, an SEM 2400 shown in FIG. 24 may be used. A major difference from the length measurement SEM 2100 shown in FIG. 21 is that the irradiation optical system 2440 includes a secondary electron detector 2404 and two backscattered

electron detectors

2402 and 2403 as detectors.

Secondary electrons emitted from the silicon wafer 106 irradiated with the electron beam 101 are bent by the ExB deflector 2401 and detected by the secondary electron detector 2404. The backscattered electrons simultaneously emitted are detected by the two backscattered

electron detectors

2402 and 2403. The detected signals are converted into digital signals by the A /

D converters

2405, 2406, and 2407 of the signal processing system 2430, respectively, and are configured into three images by the arithmetic unit 2410.

A signal processing system 2430 for detection signals includes A /

D converters

2405, 2406, and 2407 for converting analog signals output from the secondary electron detector 2404 and the two backscattered

electron detectors

2402 and 2403 into digital signals. The CPU 2413 for processing the signals converted by the A /

D converters

2405, 2406, and 2407, the LSI 2414, and the arithmetic unit 2410 having the image memory 2415 are controlled, and the SEM 2420 is controlled via the arithmetic unit 2410. A control terminal 2411 for controlling and a storage terminal 2412 for storing data are provided.

The backscattered electron image (BSE image) is effective when the wiring of each layer is divided into regions because the wiring regions of each layer are clearly separated in a multilayer wiring pattern. With the apparatus configuration of the present embodiment, the contrast correction of the multilayer wiring pattern can be easily performed.
Note that the modifications 1 to 8 described in the first embodiment can also be applied to this embodiment.

[Modification]
A modification of the second embodiment will be described. In the present modification, the parameter adjustment in step S2209 in FIG. 22 of the second embodiment is set using a preset which is a parameter set prepared in advance.

In FIG. 25, a GUI for setting contrast correction parameters using presets will be described. On the GUI screen 2501, an original image 2502 in which a measurement target pattern part is cut out from the upper detection image based on the approximate area calculated in step S2203 shown in FIG. 22 is displayed. Images 2503 to 2508 are images obtained by sequentially performing contrast correction on the original image 2502 with a plurality of preset contrast correction parameters.

Contrast correction images 2503 to 2508 are displayed side by side on the GUI 2501, and the user selects an appropriate correction result image and clicks the selection button 2510, whereby the preset used for the selected image 2509 is used as a parameter for contrast correction. Can be set. The user can easily adjust the parameters by adjusting the parameters for the contrast correction by the preset.

100, 2100, 2400 ...

Length measuring SEM

110, 2110, 2410 ...

Arithmetic unit

111, 2111, 2411 ...

Control terminal

112, 2112, 2412 ...

Storage device

115, 2115, 2415 ...

Image memory

120, 2120, 2420 ... SEM body 130 2130, 2430 ...

Signal processing system

140, 2140, 2440 ... Irradiation optical system.

Claims

A system for measuring a dimension of a pattern including a hole or groove formed on a sample using a charged particle beam,
A charged particle beam image acquisition unit that irradiates and scans a pattern including a hole or groove formed on a sample and scans the particle to acquire a charged particle beam image of the pattern including the hole or groove;
A signal processing unit that processes an image of the charged particle beam acquired by the charged particle beam image acquisition unit and measures a dimension of the pattern including the hole or groove;
A display unit having a screen for displaying a result processed by the signal processing unit, the signal processing unit,
A measurement region setting unit for setting a region of a pattern including the hole or groove for measuring a dimension in an image of the charged particle beam acquired by the charged particle beam image acquisition unit;
A contrast correction unit for correcting the contrast of the image of the charged particle beam in the pattern region including the hole or groove for measuring the dimension set in the measurement region setting unit,
The pattern processing system using a charged particle beam, wherein the signal processing unit processes an image whose contrast is corrected by the signal processing unit and measures a dimension of a pattern including the hole or groove.
2. The pattern dimension measurement system using a charged particle beam according to claim 1, wherein the contrast correction unit is a charged particle beam in a pattern region including a hole or a groove for measuring the dimension set by the measurement region setting unit. Correcting the contrast of the image, extracting the internal region of the hole or groove pattern in the image of the charged particle beam of the pattern region including the hole or groove for measuring the dimension set in the measurement region setting unit, Luminance information in the region is calculated from the inner region of the extracted hole or groove pattern, and the edge of the extracted hole or groove pattern image in the image of the charged particle beam based on the calculated luminance information is the display unit. A pattern dimension measurement system using a charged particle beam, wherein the contrast is corrected so as to be visible on the top.
2. The pattern dimension measurement system using a charged particle beam according to claim 1, wherein the measurement region setting unit is an image of a charged particle beam acquired by the charged particle beam image acquisition unit displayed on a screen of the display unit. A pattern dimension measuring system using a charged particle beam, characterized in that the area specified above is set as a pattern area including the hole or groove for measuring a dimension.
The pattern dimension measurement system using a charged particle beam according to claim 1, wherein the measurement region setting unit measures the dimension using design information of a pattern including a hole or a groove formed on the sample. A pattern dimension measurement system using a charged particle beam, wherein a pattern region including a hole or a groove is set.
2. The pattern dimension measurement system using a charged particle beam according to claim 1, wherein the contrast correction unit displays an image of the charged particle beam with adjusted contrast on a screen of the display unit, and the charged particle beam. A pattern size measurement system using a charged particle beam, wherein the contrast of the image of the charged particle beam is readjusted based on a contrast adjustment amount set on a screen on which the image is displayed.
The pattern dimension measurement system using a charged particle beam according to claim 1, wherein the signal processing unit corrects the contrast of the image of the charged particle beam under a plurality of conditions set in advance by a contrast correction unit, An image of the charged particle beam whose contrast is corrected under a plurality of conditions is displayed on the screen of the display unit, and a contrast correction condition corresponding to the image of the charged particle beam selected on the screen is set as a contrast correction condition from the next time onward. Pattern dimension measurement system using charged particle beam, characterized by setting as
A method of measuring a dimension of a pattern including a hole or groove formed on a sample using a charged particle beam,
A pattern containing holes or grooves formed on a sample is irradiated with charged particles and scanned to obtain a charged particle beam image of the pattern containing holes or grooves,
Processing the acquired image of the charged particle beam to measure the dimension of the pattern including the hole or groove;
Displaying the processed result on a screen, and measuring the dimension of the pattern including the hole or groove,
Set a region of the pattern including the hole or groove for measuring the dimension in the acquired image of the charged particle beam,
Correct the contrast of the image of the charged particle beam in the pattern area including the hole or groove for measuring the set dimension,
A pattern dimension measuring method using a charged particle beam, wherein the dimension of a pattern including the hole or groove is measured by processing an image with the contrast corrected.
8. A pattern dimension measuring method using a charged particle beam according to claim 7, wherein correcting the contrast of an image of the charged particle beam in the set pattern region is a hole or groove for measuring the set dimension. The inside area of the hole or groove pattern in the image of the charged particle beam in the pattern area including the pattern is extracted, luminance information in the area is calculated from the extracted inner area of the hole or groove pattern, and the calculated luminance information is included in the calculated luminance information. A pattern size measuring method using a charged particle beam, wherein the contrast is corrected so that an edge of the extracted hole or groove pattern image in the charged particle beam image can be visually recognized on the display unit.
8. A pattern dimension measuring method using a charged particle beam according to claim 7, wherein a region of the pattern is set on an image of the charged particle beam displayed on the screen. The pattern dimension measurement method used.
The pattern dimension measuring method using a charged particle beam according to claim 7, wherein the pattern area is set using design information of a pattern including a hole or a groove formed on the sample. Pattern dimension measurement method using charged particle beam.
8. The pattern dimension measuring method using a charged particle beam according to claim 7, wherein the correction of the contrast displays an image of the charged particle beam with the contrast adjusted on the screen, and the charged particle beam A charged particle comprising: setting a contrast adjustment amount on a screen on which an image of the image is displayed; and re-adjusting the contrast of the charged particle beam image based on the set contrast adjustment amount Pattern dimension measurement method using lines.
8. A pattern dimension measuring method using a charged particle beam according to claim 7, wherein a correction is made in advance for correcting a contrast of an image of the charged particle beam in a pattern region including a hole or a groove for measuring the set dimension. The contrast of the image of the charged particle beam is corrected under the plurality of conditions, and the plurality of images of the charged particle beam with the contrast corrected under the plurality of conditions are displayed on the screen of the display unit and displayed on the screen. A pattern dimension measurement method using a charged particle beam, characterized in that a contrast correction condition corresponding to an image selected from a plurality of images is set as a contrast correction condition for the next and subsequent times.
A method of measuring a dimension of a pattern including a hole or groove formed on a sample using a charged particle beam,
A pattern containing holes or grooves formed on a sample is irradiated with charged particles and scanned to obtain a charged particle beam image of the pattern containing holes or grooves,
Processing the acquired image of the charged particle beam to measure the dimension of the pattern including the hole or groove;
Displaying the processed result on a screen, and measuring the dimension of the pattern including the hole or groove,
Displaying an image of the acquired charged particle beam and an image obtained by correcting the contrast of the image on a screen;
Correct the contrast correction condition of the image on the displayed screen,
A pattern dimension measurement method using a charged particle beam, wherein the dimension of a pattern including the hole or groove is measured by processing an image whose contrast is corrected under the corrected correction condition.
The pattern dimension measurement method using a charged particle beam according to claim 13, wherein the acquired image of the charged particle beam displayed on the screen and the image in which the contrast of the image is corrected include the acquired hole or A pattern dimension measurement method using a charged particle beam, wherein the pattern is an image of a specified region of a charged particle beam image including a groove.
14. The pattern dimension measurement method using a charged particle beam according to claim 13, wherein correcting a contrast correction condition of the image on the displayed screen is performed in the image of the pattern including the hole or groove. A pattern dimension measuring method using a charged particle beam, wherein a contrast correction condition is corrected so that a contrast between an edge of a hole or groove pattern and a periphery of the hole or groove pattern is increased.