Analyzing device, system, method, and program

Abstract

Provided are an analyzing device, system, method, and program for analyzing the inclination of a specimen surface. The analyzing device comprises: a two-dimensional profile acquiring unit that acquires a two-dimensional profile obtained by detecting laser light reflected or diffracted by a specimen surface; a line profile generating unit that, with respect to a first straight line in the two-dimensional profile along which a plurality of peaks are linearly arranged and a second straight line in the two-dimensional profile which is orthogonal to the first straight line and along which a plurality of peaks are linearly arranged, generates a first line profile obtained by integrating, in a direction perpendicular to the first straight line, a predetermined region including at least a part of each of the first straight line and the second straight line, and a second line profile obtained by integrating the predetermined region in a direction perpendicular to the second straight line; a reflection position determining unit that determines a reflection position of the two-dimensional profile on the basis of the first line profile and the second line profile; and an inclination calculating unit that calculates the inclination of the specimen surface on the basis of the reflection position.

Description

Analysis Device, System, Method, and Program

[0001] The present invention relates to an analysis device, system, method, and program for analyzing the inclination of a sample surface.

[0002] In an X-ray analyzer, adjusting the angle between the sample surface and the optical axis of the X-ray during sample analysis or processing is an important step. For example, in T-SAXS (transmission small-angle X-ray scattering), it is required to accurately measure the tilt angle of a deep hole / deep groove pattern with respect to the wafer surface. To achieve this, it is first necessary to determine a reference position where the wafer surface and the optical axis of the X-ray are perfectly orthogonal. Currently, in T-SAXS, an autocollimator is used to adjust the inclination of the wafer surface with respect to the optical axis of the X-ray. Specifically, a laser with a wavelength of several hundred nanometers is used, and the direction of specular reflection is measured based on the position of the detected reflected light.

[0003] Patent Document 1 describes a method and apparatus for cutting a single crystal that can be accurately cut and increase the wafer yield during cutting. The technique disclosed in Patent Document 1 includes a step of measuring the angle between the crystal plane and the outer surface of the single crystal using a device outside the cutting machine, a step of measuring the orientation of the outer surface using an autocollimation telescope after measuring the angle, a step of positioning the single crystal based on the orientation of the outer surface such that a predetermined crystal plane forms a predetermined angle with the feed direction, and a step of performing cutting. The step of measuring the angle between the crystal plane and the outer surface includes a step of measuring the angle formed by the outer surface with respect to the reference axis using an autocollimation telescope, a step of measuring the angle of the crystal plane with respect to the reference axis using an X-ray goniometer, and a step of subtracting the measured angles from each other to obtain a correction value. The step of positioning the single crystal includes a step of positioning based on the measured orientation of the outer surface and the obtained correction value using an alignment device.

[0004] Japanese Unexamined Patent Application Publication No. 2011-003929

[0005] The surface of semiconductor device wafers may contain periodic structures ranging from several hundred nanometers to several hundred micrometers, in addition to the device pattern. When wafers contain these periodic structures, strong diffracted light other than specular reflection may be observed in the autocollimator image (two-dimensional profile). This diffracted light can sometimes be observed more strongly than specular reflection, and recently, there has been an increase in cases where incorrect wafer surface tilt adjustments are made.

[0006] For samples where surface diffraction does not need to be considered, the inclination of the sample surface can be measured by using an autocollimation telescope (autocollimator) as is done in Patent Document 1. Conventional methods using an autocollimator include, for example, searching for pixels with high intensity in the autocollimator image, creating a line profile in a very narrow range near those pixels, and determining the peak position. However, conventional methods using an autocollimator do not take into account the periodic structure of the wafer surface, and therefore could not handle cases where strong diffracted light other than specular reflection was observed in the autocollimator image. Therefore, it was necessary to establish a method for determining the specular reflection position that is not affected by surface diffraction.

[0007] As a result of diligent research, the inventors have discovered a method for determining the location of specular reflection even when strong diffracted light other than specular reflection is observed on the autocollimator, and have completed the present invention.

[0008] This invention has been made in view of these circumstances, and aims to provide an analytical apparatus, system, method, and program for analyzing the inclination of a sample surface.

[0009] (1) In order to achieve the above objective, the analytical apparatus of the present invention employs the following means. That is, an analytical apparatus according to one aspect of the present invention is an analytical apparatus for analyzing the inclination of a sample surface, comprising: a two-dimensional profile acquisition unit that acquires a two-dimensional profile obtained by detecting laser light reflected or diffracted by the sample surface; a line profile generation unit that generates a first line profile and a second line profile obtained by integrating a predetermined region in a direction perpendicular to the first line and a predetermined region in which a first line in which a plurality of peaks are arranged linearly and a second line perpendicular to the first line in which a plurality of peaks are arranged linearly, with respect to a first line in which a plurality of peaks are arranged linearly and a second line perpendicular to the first line, with respect to a predetermined region that includes at least a part of each of the first line and the second line, respectively; a reflection position determination unit that determines the reflection position of the two-dimensional profile based on the first line profile and the second line profile; and a slope calculation unit that calculates the inclination of the sample surface based on the reflection position of the two-dimensional profile.

[0010] (2) In addition, in an analytical apparatus according to one aspect of the present invention, the lengths of the first linear direction and the second linear direction of the predetermined region are 10 times or more the full width at half maximum of the peak having the maximum peak intensity among the plurality of peaks.

[0011] (3) In addition, in an analysis apparatus according to one embodiment of the present invention, the predetermined region is the largest rectangle included in the two-dimensional profile.

[0012] (4) In addition, in an analysis apparatus according to one aspect of the present invention, the line profile generation unit generates the first line profile or the second line profile by subtracting a background that is set in advance or determined based on the two-dimensional profile from the integral value when generating the first line profile or the second line profile.

[0013] (5) In addition, in an analysis apparatus according to one aspect of the present invention, the two-dimensional profile generated by the line profile generation unit is a two-dimensional profile rotated such that the direction of the first straight line and the direction of the second straight line are in predetermined directions, and the reflection position determination unit determines the reflection position of the two-dimensional profile before rotation based on the center and angle of rotation.

[0014] (6) Furthermore, a system according to one aspect of the present invention includes an X-ray analyzer comprising an X-ray generating unit for generating X-rays, a detector for detecting X-rays, and a sample stage for controlling the rotation of a sample; an autocollimator for generating the two-dimensional profile by irradiating the surface of a sample placed on the sample stage with laser light; and the analysis apparatus according to any one of (1) to (5) above.

[0015] (7) Another method according to one aspect of the present invention is a method for analyzing the inclination of a sample surface, comprising: obtaining a two-dimensional profile by detecting laser light reflected or diffracted by the sample surface; generating a first line profile and a second line profile by integrating the predetermined region in a direction perpendicular to the first line and perpendicular to the second line, with respect to a first line in which a plurality of peaks are arranged linearly and a second line perpendicular to the first line, with respect to a predetermined region that includes at least a part of the first line and the second line, respectively; determining the reflection position of the two-dimensional profile based on the first line profile and the second line profile; and calculating the inclination of the sample surface based on the reflection position of the two-dimensional profile.

[0016] (8) Another aspect of the present invention is a program for analyzing the inclination of a sample surface, which causes a computer to perform the following steps: a process of acquiring a two-dimensional profile by detecting laser light reflected or diffracted by the sample surface; a process of generating a first line profile by integrating a predetermined region in a direction perpendicular to the first line and a second line profile by integrating a predetermined region in a direction perpendicular to the first line and a second line profile in a direction perpendicular to the second line, with respect to a first line in which a plurality of peaks are arranged linearly and a second line perpendicular to the first line, with respect to a predetermined region that includes at least a part of the first line and the second line, respectively; a process of determining the reflection position of the two-dimensional profile based on the first line profile and the second line profile; and a process of calculating the inclination of the sample surface based on the reflection position of the two-dimensional profile.

[0017] This is a schematic diagram showing a two-dimensional profile in which strong diffracted light other than specular reflection was observed. This is a schematic diagram showing that a first line AA and a second line BB have been set on the two-dimensional profile of Figure 1. This is a line profile showing the relative pixel intensity of pixels on the first line AA. This is a line profile showing the relative pixel intensity of pixels on the second line BB. This is the first line profile obtained by integrating the entire two-dimensional profile in a direction perpendicular to the first line AA. This is the second line profile obtained by integrating the entire two-dimensional profile in a direction perpendicular to the second line BB. This is a conceptual diagram showing an example of the configuration of the system of the present invention. This is a block diagram showing an example of the configuration of the control device. This is a block diagram showing a modified example of the configuration of the control device. This is a block diagram showing an example of the configuration of the analysis device according to Embodiment 1. This is a schematic diagram showing an example of setting a predetermined region on the two-dimensional profile of Figure 2. This is a schematic diagram showing the two-dimensional profile before background processing of the same two-dimensional profile as in Figure 1. This is the first line profile created based on the two-dimensional profile of Figure 12. This is the second line profile created based on the two-dimensional profile of Figure 12. This is a flowchart showing an example of the operation of the analysis device according to Embodiment 1. This flowchart shows a modified operation of the analysis device according to Embodiment 1. This flowchart shows an example of the operation of the entire system. This flowchart shows an example of the operation of the analysis device according to Embodiment 2. This flowchart shows a modified operation of the analysis device according to Embodiment 2.

[0018] Next, embodiments of the present invention will be described with reference to the drawings. To facilitate understanding of the description, the same reference numerals are used for identical components in each drawing, and redundant descriptions are omitted.

[0019] [Principle] Figure 1 is a schematic diagram showing a two-dimensional profile in which strong diffracted light other than specular reflection is observed. Figure 1 shows the logarithm of the pixel intensity of the autocollimator's two-dimensional detector as grayscale. As shown in Figure 1, in a two-dimensional profile in which strong diffracted light other than specular reflection is observed, there are multiple pixels (peaks) with high intensity. Therefore, even if a pixel with high intensity is searched for, it cannot be said that the specular reflection position is near that pixel. Note that Figure 1 is a schematic diagram of a two-dimensional profile after background processing, which will be described later.

[0020] Figure 2 is a schematic diagram showing the setting of a first line AA and a second line BB on the two-dimensional profile of Figure 1. Both the first line AA and the second line BB have multiple peaks aligned. The second line BB is also orthogonal to the first line AA. Figure 3 is a line profile showing the relative pixel intensity of pixels on the first line AA. Figure 4 is a line profile showing the relative pixel intensity of pixels on the second line BB. From Figures 3 and 4, it can be seen that in two-dimensional profiles where strong diffracted light other than specular reflection is observed, it is difficult to search for pixels with high intensity, and it cannot be said that the specular reflection position is near the pixel with the highest intensity.

[0021] Figure 5 shows the first line profile obtained by integrating the entire two-dimensional profile in a direction perpendicular to the first line AA. Figure 6 shows the second line profile obtained by integrating the entire two-dimensional profile in a direction perpendicular to the second line BB. In this sample, it was confirmed that the actual specular reflection location is near the pixel with the strongest intensity in Figures 5 and 6. That is, by creating a line profile using a wide range as shown in Figures 5 and 6, the location of specular reflection can be determined even in a two-dimensional profile where strong diffracted light other than specular reflection is observed. The detailed method of the present invention will be described in detail in the embodiments.

[0022] [Embodiments] (Embodiment 1) [System] Figure 7 is a conceptual diagram showing an example of the configuration of the system 10 of the present invention. The system 10 includes an X-ray analyzer 100, an autocollimator 200, a control device 300, and an analysis device 400. By using such a system 10, the inclination of the surface of a sample placed on the X-ray analyzer 100 can be analyzed. Note that the configuration shown in Figure 7 is just one example, and various other configurations can be adopted.

[0023] Note that in Figure 7, the control device 300 and the analysis device 400 are shown as the same PC. However, as shown in Figure 8, the analysis device 400 may be configured as a separate device from the control device 300. Figure 8 is a block diagram showing an example of the configuration of the control device 300. Also, as shown in Figure 9, the analysis device 400 may be configured as a part of the functions included in the control device 300. Figure 9 is a block diagram showing a modified configuration of the control device 300. Furthermore, the analysis device 400 and the control device 300 may be configured as an integrated device. Below, we will describe the case where the control device 300 and the analysis device 400 are configured as separate devices.

[0024] [X-ray analyzer] The X-ray analyzer 100 comprises an optical system that incidents X-rays onto a sample and detects reflected X-rays, scattered X-rays, diffracted X-rays, etc., generated from the sample. The X-ray analyzer 100 includes an X-ray generating unit 110 that generates X-rays from an X-ray focal point, i.e., an X-ray source, a sample stage 140 on which the sample is placed, and a detector 160 that detects X-rays. The X-ray analyzer 100 has a mechanism to adjust the tilt of the sample stage 140 based on the analysis of the analysis device 400. The mechanism for adjusting the tilt of the sample stage 140 can be, for example, the Rx axis and Ry axis of the sample stage 140, but is not limited to these. The X-ray analyzer 100 may also include an incident optical unit 120, a goniometer 130 that controls the rotation of the sample, or an exit optical unit 150. The X-ray analyzer 100 consists of an X-ray generator 110, an incident optical unit 120, a goniometer 130, a sample stage 140, an exit optical unit 150, and a detector 160. Since these components can be standard types, their descriptions are omitted.

[0025] The X-ray analyzer 100 repeatedly moves its rotation axis and projects X-rays under predetermined conditions. This irradiates the sample with X-rays and acquires measurement data such as X-ray reflectance data and small-angle X-ray scattering data. The X-ray analyzer 100 transmits device information and the acquired measurement data to the control device 300.

[0026] [Autocollimator] The autocollimator 200 comprises a light source that emits laser light of a predetermined wavelength, an optical unit that adjusts the optical path of the laser light, and a two-dimensional detector that detects the laser light reflected or diffracted from the sample surface. Specific examples of the optical unit include lenses and mirrors. The light source, optical unit, and two-dimensional detector that constitute the autocollimator 200 can be general-purpose components, so their explanation is omitted.

[0027] The autocollimator 200 emits laser light from a light source and detects the laser light reflected or diffracted from the sample surface with a two-dimensional detector. The autocollimator 200 generates a two-dimensional profile based on the intensity of the laser light detected by the two-dimensional detector. By determining the position of the reflected light in the two-dimensional profile (also called the reflection position or specular reflection position), the inclination of the sample surface can be determined. The autocollimator 200 transmits the generated two-dimensional profile to the control device 300. The autocollimator 200 may also transmit device information of the autocollimator 200, etc., to the control device 300 along with the two-dimensional profile.

[0028] [Control Device] The control device 300 is connected to the X-ray analyzer 100 and the autocollimator 200, and controls the X-ray analyzer 100 and the autocollimator 200, processes the acquired data, and stores it. The control device 300 is a device equipped with a CPU and memory, and may be a PC terminal or a server on the cloud. In addition, not only the entire device, but also some of the devices or some of the functions within the device may be located on the cloud.

[0029] The control device 300 is composed of a computer with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and memory connected to a bus. The control device 300 is connected to the X-ray analyzer 100 and the autocollimator 200 to receive information.

[0030] The control device 300 comprises a control unit 310, a device information storage unit 320, a measurement data storage unit 330, and a display unit 340. Each unit can send and receive information via a control bus L. The input device 510 and the display device 520 are connected to the CPU via appropriate interfaces. The input device 510 is, for example, a keyboard or mouse, and provides input to the control device 300. The display device 520 is, for example, a display, and displays two-dimensional profiles, measurement data, etc.

[0031] The control unit 310 controls the operation of the X-ray analyzer 100 and the autocollimator 200. The control unit 310 also controls a mechanism that adjusts the tilt of the sample stage 140 of the X-ray analyzer 100 based on the tilt of the sample calculated by the analysis device 400. This allows adjustment of the angle between the sample surface and the X-ray optical axis. For example, in T-SAXS, the reference position where the sample surface and the X-ray optical axis are perpendicular can be precisely determined, enabling accurate measurement of the tilt angle of deep holes and deep grooves relative to the sample surface.

[0032] The device information storage unit 320 stores device information of the X-ray analyzer 100 obtained from the X-ray analyzer 100. The device information of the X-ray analyzer may include information about the X-ray analyzer 100, such as the device name, type of radiation source, wavelength, and background. The device information storage unit 320 may also store device information of the autocollimator 200 obtained from the autocollimator 200. The device information of the autocollimator 200 may include information about the autocollimator 200, such as the device name, type of light source, wavelength, and background.

[0033] The measurement data storage unit 330 stores measurement data acquired from the X-ray analyzer 100. Along with the measurement data, it may also store information about the X-ray analyzer 100, such as the type of radiation source, wavelength, and background. The measurement data storage unit 330 may also store a two-dimensional profile acquired from the autocollimator 200. Along with the two-dimensional profile, it may also store information about the autocollimator 200, such as the type of light source, wavelength, and background. The display unit 340 displays the measurement data or two-dimensional profile on the display device 520. This allows the user to confirm the measurement data or two-dimensional profile. Furthermore, the user can instruct or specify the control device 300, analysis device 400, etc., based on the measurement data or two-dimensional profile.

[0034] [Analysis Device] The analysis device 400 analyzes the inclination of the sample surface. The analysis device 400 is a device equipped with a CPU and memory, and may be a PC terminal or a server on the cloud. Furthermore, not only the entire device, but also some of the devices or some of the functions within the device may be provided on the cloud.

[0035] Figure 10 is a block diagram showing an example of the configuration of the analysis device 400 according to Embodiment 1. Embodiment 1 describes the analysis device 400 when a line profile is created directly from a two-dimensional profile. The analysis device 400 is composed of a computer with a CPU, ROM, RAM, and memory connected to a bus. The analysis device 400 may be connected directly to the X-ray analyzer 100 or autocollimator 200 or via the control device 300 to receive information. The analysis device 400 may also control the operation of the X-ray analyzer 100 or autocollimator 200.

[0036] The analysis device 400 includes a two-dimensional profile acquisition unit 410, a line profile generation unit 420, a reflection position determination unit 430, and a tilt calculation unit 440. Each unit can send and receive information via a control bus L. If the analysis device 400 and the control device 300 are configured separately, the input device 510 and the display device 520 are also connected to the CPU of the analysis device 400 via an appropriate interface. In this case, the input device 510 and the display device 520 may be different from those connected to the control device 300. The input device 510 is, for example, a keyboard or mouse, and provides input to the control device 300 and the analysis device 400. The display device 520 is, for example, a display, which displays the two-dimensional profile, the determined reflection position, the calculated tilt of the sample, etc.

[0037] The two-dimensional profile acquisition unit 410 acquires a two-dimensional profile by detecting the laser light reflected or diffracted at the sample surface. The two-dimensional profile acquisition unit 410 acquires the two-dimensional profile directly from the autocollimator 200 or via the control device 300.

[0038] The line profile generation unit 420 generates a first line profile and a second line profile by integrating in a direction perpendicular to the first line and in a direction perpendicular to the second line, respectively, with respect to a first line in which multiple peaks are aligned linearly and a second line perpendicular to the first line in a two-dimensional profile, and a region that contains at least a part of the first line and the second line, respectively, as a predetermined region. The predetermined region may be a rectangular region with four sides parallel to the first line and the second line as its boundaries.

[0039] Figure 11 is a schematic diagram showing an example of setting a predetermined region in the two-dimensional profile of Figure 2. As shown in Figure 11, the predetermined region does not have to be the entire two-dimensional profile. The first line, the second line, or the predetermined region may be automatically set by the line profile generation unit 420 by analyzing the distribution of peak intensity of the two-dimensional profile. The first line, the second line, or the predetermined region may also be set by user instruction. These may also be combined. The shape of the two-dimensional profile may change depending on the shape of the two-dimensional detector, but the shape of the two-dimensional profile can be anything.

[0040] In a two-dimensional profile, the predetermined region is preferably the largest rectangle included in the two-dimensional profile. This allows for high accuracy in determining the reflection position in the two-dimensional profile, even when diffracted light is observed to be stronger than specular reflection.

[0041] In typical autocollimator usage, a line profile including the peak is sometimes created to obtain the peak shape. When creating a line profile including the peak, a region slightly larger than the peak's full width at half maximum (FWHM) is sometimes specified for integration. In this case, almost no diffraction intensity is obtained at positions 3 to 5 times the FWHM from the peak top. Therefore, the integration region is not set to a wide range of 10 times or more the peak's FWHM.

[0042] On the other hand, in this invention, instead of specifying a region containing a single peak, a region containing multiple peaks is designated as the predetermined region. Therefore, it is preferable that the predetermined region occupies a large area of ​​the two-dimensional profile, and more preferably that it covers the entire area of ​​the acquired two-dimensional profile. Here, the predetermined region occupies a large area of ​​the two-dimensional profile if the lengths of the first linear direction and the second linear direction of the predetermined region are 10 times or more the full width at half maximum of the peak showing the maximum peak intensity. This makes it possible to increase the accuracy of determining the reflection position of the two-dimensional profile even when the diffracted light is observed to be stronger than the specular reflection. The length of the first linear direction or the second linear direction may be 50 times or more the full width at half maximum of the peak showing the maximum peak intensity among the multiple peaks. As described above, it is preferable that the lengths of the first linear direction and the second linear direction of the predetermined region are long, so there is no need to set an upper limit.

[0043] When the line profile generation unit 420 generates a first line profile or a second line profile, it is preferable to generate the first line profile or the second line profile by subtracting a background that has been set in advance or determined based on the two-dimensional profile from the integral value. This reduces the influence of natural noise present in each pixel of the two-dimensional detector and allows for appropriate integration of the intensity due to reflected and diffracted light. As a result, the accuracy of determining the reflection position of the two-dimensional profile can be improved. Subtracting a background that has been set in advance or determined based on the two-dimensional profile from the integral value can also be referred to as background processing.

[0044] Examples of the method for determining the background to be subtracted include, for example, the following methods. (i) Using a Si wafer or the like where surface diffraction is not observed, measure the background of each pixel in advance. The measured background is used for subtraction as the background of each pixel. In this method, it is necessary to perform two or more measurements with the orientation of the Si wafer changed. (ii) Among the values of each pixel in the two-dimensional profile obtained by measuring the test sample, regard a predetermined value (for example, the minimum value) as the common background for each pixel. (iii) Sort the values of each pixel in the two-dimensional profile obtained by measuring the test sample in ascending order of magnitude, and regard the value including a predetermined number of pixels (for example, half of the pixels) among all the detected surfaces as the common background for each pixel. Note that the method for determining the background of the present invention is not limited to the above methods.

[0045] In the present invention, various methods can be applied to the background processing. For example, a two-dimensional profile obtained by subtracting the background preset or determined based on the two-dimensional profile from the two-dimensional profile may be created, and a line profile may be generated based on the subtracted two-dimensional profile and a predetermined region. Also, for example, the total of the backgrounds of the pixels on each straight line in the integration direction within a predetermined region may be obtained and subtracted from the integrated value of the line profile.

[0046] FIG. 12 is a schematic diagram showing the two-dimensional profile before background processing of the same two-dimensional profile as in FIG. 1. Note that the background of the two-dimensional profile in FIG. 1 was determined using the method (ii) described above. FIG. 13 is the first line profile created based on the two-dimensional profile in FIG. 12. FIG. 14 is the second line profile created based on the two-dimensional profile in FIG. 12. The line profiles in FIGS. 13 and 14 were generated by setting the first straight line AA and the second straight line BB at the same positions as in FIG. 2.

[0047] As can be seen from FIG. 13 or FIG. 14, the reflection position of the two-dimensional profile can be determined even when no background processing is performed. However, as shown in FIG. 3 or FIG. 4, by performing background processing to create a line profile, the accuracy of determining the reflection position of the two-dimensional profile can be improved.

[0048] The reflection position determination unit 430 determines the reflection position of the two-dimensional profile based on the first line profile and the second line profile. In the present invention, various methods can be applied to the method of determining the reflection position of the two-dimensional profile. The reflection position of the two-dimensional profile can be determined by, for example, existing peak search algorithms such as the peak top method, the centroid connection method, and the centroid method. Further, the reflection position of the two-dimensional profile can also be determined by fitting using, for example, a Gaussian function or a Lorentz function.

[0049] The inclination calculation unit 440 calculates the inclination of the sample surface based on the reflection position of the two-dimensional profile determined by the reflection position determination unit 430. The inclination of the sample surface can be calculated from the direction and magnitude of the deviation of the reflection position from the reference position of the two-dimensional profile. The correspondence between the direction and magnitude of the deviation of the reflection position from the reference position and the inclination of the sample surface varies depending on the configuration of the autocollimator 200 and the like.

[0050] (Explanation of the flow when calculating the inclination of the sample without rotating the two-dimensional profile) FIG. 15 is a flowchart showing an example of the operation of the analysis apparatus 400 according to Embodiment 1. FIG. 15 shows an example of the operation when calculating the inclination of the sample without rotating the two-dimensional profile. First, the analysis apparatus 400 acquires a two-dimensional profile by the two-dimensional profile acquisition unit 410 (step S1). Next, the first line profile and the second line profile are generated by the line profile generation unit 420 (step S2). Next, the reflection position is determined by the reflection position determination unit 430 (step S3). Then, the inclination is calculated by the inclination calculation unit 440 (step S4). If necessary, the reflection position and the inclination may be displayed.

[0051] In this way, by determining the reflection position based on the first and second line profiles, the accuracy of determining the reflection position of the two-dimensional profile can be increased even when the diffracted light is observed to be stronger than the specular reflection. Furthermore, if the line profile generation unit 420 can integrate along all directions of the two-dimensional profile, the tilt of the sample can be calculated without rotating the two-dimensional profile.

[0052] (Explanation of the flow when background processing is performed) Figure 16 is a flowchart showing a modified operation of the analysis device 400 according to Embodiment 1. Figure 16 shows an example of operation when background processing is performed. First, the analysis device 400 acquires a two-dimensional profile using the two-dimensional profile acquisition unit 410 (step T1). Next, the line profile generation unit 420 performs background processing on the two-dimensional profile (step T2). Next, the line profile generation unit 420 generates a first line profile and a second line profile (step T3). Next, the reflection position determination unit 430 determines the reflection position (step T4). Then, the inclination calculation unit 440 calculates the inclination (step T5). The reflection position and inclination may be displayed as needed. Background processing may also be performed on each line profile after the line profiles have been generated.

[0053] In this way, background processing of the two-dimensional profile can reduce the influence of natural noise on each pixel of the two-dimensional detector, and allow for proper integration of the intensity due to reflected and diffracted light.

[0054] (Explanation of the system flow) Figure 17 is a flowchart showing an example of the operation of the entire system 10. As a preparation step, the sample is placed on the sample stage 140 of the X-ray analyzer 100. Next, the autocollimator 200 generates a two-dimensional profile (step U1). The two-dimensional profile can be generated by irradiating a predetermined position on the surface of the sample with laser light and detecting the reflected or diffracted light with the two-dimensional detector of the autocollimator. Next, the analysis device 400 acquires the two-dimensional profile and calculates the tilt (step U2). Step U2 can be either the flow of the analysis device 400 according to Embodiment 1 described above, or the flow of the analysis device 400 according to the second embodiment described later, or a flow including both. Then, the system 10 adjusts the tilt of the sample (step U3). The tilt of the sample can be set to a desired direction or angle depending on the purpose of the X-ray analyzer 100.

[0055] By using such a system to determine the reflection position based on the first and second line profiles, the accuracy of determining the reflection position of the two-dimensional profile can be increased, even when diffracted light is observed to be stronger than specular reflection.

[0056] (Embodiment 2) [Analysis Apparatus] Embodiment 2 describes an analysis apparatus 400 used when a line profile is created after rotating a two-dimensional profile. The configuration of the system 10, X-ray analyzer 100, autocollimator 200, control device 300, and analysis apparatus 400 is the same as in Embodiment 1, so a description will be omitted. Note that some or all of the apparatus or operations described in Embodiment 1 can also be applied to Embodiment 2. The following describes the parts of the analysis apparatus 400 according to Embodiment 2 that differ from those in Embodiment 1.

[0057] The two-dimensional profile generated by the line profile generation unit 420 is a two-dimensional profile (rotated two-dimensional profile) obtained by rotating the two-dimensional profile (the two-dimensional profile generated by the autocollimator 200) so that the direction of the first straight line and the direction of the second straight line are predetermined integration directions of the line profile generation unit 420. The predetermined integration direction is the direction in which the line profile generation unit 420 can integrate. This makes it possible to create a line profile even if the line profile generation unit 420 can only integrate in a predetermined direction.

[0058] The rotation of the two-dimensional profile may be performed by the two-dimensional profile acquisition unit 410 of the analysis device 400 or another functional unit that performs image conversion such as rotation, or by an external device. When the rotation of the two-dimensional profile is performed by an external device, the two-dimensional profile acquisition unit 410 acquires information on the center of rotation and the rotation angle along with the rotated two-dimensional profile. When the analysis device 400 performs the rotation of the two-dimensional profile, the center of rotation and the rotation angle can be set based on a first line or a second line and a predetermined integration direction. Alternatively, the user may set them. When an external device performs the rotation of the two-dimensional profile, the external device shall be able to acquire the information necessary to set the center of rotation and the rotation angle. The center of rotation may be set anywhere in the two-dimensional profile, but it is preferable that it be close to the center of the two-dimensional profile. The center of rotation may be preset according to the two-dimensional profile.

[0059] Even if the analysis device 400 has a function to rotate the two-dimensional profile, if the direction of the first straight line and the direction of the second straight line of the two-dimensional profile acquired by the two-dimensional profile acquisition unit 410 coincide with the predetermined integration direction of the line profile generation unit 420, the analysis device 400 does not need to generate a rotated two-dimensional profile. Furthermore, if the line profile generation unit 420 of the analysis device 400 can only integrate in a predetermined direction and does not have a function to perform image conversion, the system 10 may determine the angle between the first or second straight line and the predetermined direction, rotate the sample stage 140 in the reverse direction by that angle, and then generate the two-dimensional profile again. In this case, the analysis device 400 can acquire information on the center of rotation and the rotation angle of the rotated two-dimensional profile. However, the center of rotation of the sample stage 140 must coincide with the point where the laser beam of the autocollimator 200 is irradiated.

[0060] When the analysis device 400 generates a two-dimensional profile after rotation, or when the two-dimensional profile acquisition unit 410 acquires a two-dimensional profile after rotation, the line profile generation unit 420 generates a first line profile and a second line profile based on the two-dimensional profile after rotation. The reflection position determination unit 430 determines the reflection position of the two-dimensional profile before rotation based on the rotation center and angle of the two-dimensional profile after rotation. The reflection position of the two-dimensional profile before rotation can be determined, for example, by determining the reflection position of the two-dimensional profile after rotation and rotating it in the opposite direction by the amount of the rotation angle around the rotation center of the two-dimensional profile after rotation.

[0061] (Explanation of the flow when the analysis device generates a two-dimensional profile after rotation and calculates the tilt of the sample) Figure 18 is a flowchart showing an example of the operation of the analysis device 400 according to Embodiment 2. Figure 18 shows an example of the operation when the analysis device generates a two-dimensional profile after rotation and calculates the tilt of the sample. First, the analysis device 400 acquires a two-dimensional profile using the two-dimensional profile acquisition unit 410 (step V1). Next, it generates a two-dimensional profile after rotation (step V2). Next, it generates a first line profile and a second line profile using the line profile generation unit 420 (step V3). Next, it determines the reflection position using the reflection position determination unit 430 (step V4). The reflection position to be determined is the reflection position of the two-dimensional profile before rotation. Then, it calculates the tilt using the tilt calculation unit 440 (step V5). If necessary, the reflection position, tilt, center of rotation, or rotation angle may be displayed. In addition, background processing may be performed in the above flow.

[0062] (Explanation of the flow when the analysis device acquires a two-dimensional profile after rotation and calculates the tilt of the sample) Figure 19 is a flowchart showing a modified operation of the analysis device 400 according to Embodiment 2. Figure 19 shows an example of the operation when the analysis device acquires a two-dimensional profile after rotation and calculates the tilt of the sample. First, the analysis device 400 acquires a two-dimensional profile after rotation using the two-dimensional profile acquisition unit 410 (step W1). At this time, the two-dimensional profile acquisition unit 410 acquires information on the center of rotation and the rotation angle of the two-dimensional profile after rotation, along with the two-dimensional profile after rotation. Next, the line profile generation unit 420 generates a first line profile and a second line profile (step W2). Next, the reflection position determination unit 430 determines the reflection position (step W3). The reflection position to be determined is the reflection position of the two-dimensional profile before rotation. Then, the tilt calculation unit 440 calculates the tilt (step W4). The reflection position, tilt, center of rotation, or rotation angle may be displayed as needed. In addition, background processing may be performed in the above flow.

[0063] [Examples] (Example 1) Using the system 10 configured as described above, the reflection position was determined for a Si wafer in which surface diffraction was significantly observed, using both the method of the present invention and a conventional method. Specifically, 35 points were set in a grid pattern at 1 mm intervals on the surface of the Si wafer, and 100 measurements were taken with an autocollimator for each of the 35 points to generate a two-dimensional profile. Next, the reflection position was determined using the method of the present invention based on each generated two-dimensional profile, and the inclination of the wafer surface was calculated. The average value of the angles in each coordinate direction (x coordinate, y coordinate) of the 100 inclinations calculated for each point, and the reproducibility 3σ were calculated. Furthermore, the reflection position was determined using a conventional method based on the same two-dimensional profile, and the inclination of the wafer surface was calculated. For points in which the reflection position could be determined for all two-dimensional profiles, the average value of the angles in each coordinate direction of the 100 reflection positions, and the reproducibility 3σ were calculated. Note that the two-dimensional profiles used were those that had undergone background processing.

[0064] In the method of the present invention, the reflection position could be determined for all two-dimensional profiles of all points, and there were no results that appeared to be false detections. Furthermore, the reproducibility 3σ for each point fell within the range of 0.00017° to 0.00062° in the x-coordinate direction and 0.00045° to 0.00103° in the y-coordinate direction. On the other hand, in the conventional method, reading errors occurred at 16 out of 35 points, and 6 points included results that appeared to be false detections in either the x-coordinate or y-coordinate direction. For the 13 points where the reflection position could be determined without including results that appeared to be false detections, the reproducibility 3σ for each point fell within the range of 0.00013° to 0.00084° in the x-coordinate direction and 0.00054° to 0.00138° in the y-coordinate direction.

[0065] As a result of the above, it was confirmed that the method of the present invention can determine the reflection position even in samples where surface diffraction is significantly observed, which may cause reading errors or false detections with conventional methods, and that the accuracy is sufficiently high.

[0066] (Example 2) Using the same system 10 as in Example 1, the tilt of a Si wafer in which no surface diffraction was observed was calculated using the method of the present invention and the conventional method. Specifically, one point was set on the surface of the Si wafer, and 100 measurements were taken with an autocollimator to generate a two-dimensional profile. Based on each of the generated two-dimensional profiles, the reflection position was determined using the method of the present invention, and the tilt of the wafer surface was calculated. The average value of the angles in each coordinate direction (x coordinate, y coordinate) of the calculated tilt and the reproducibility 3σ were then calculated. Furthermore, based on the same two-dimensional profile, the reflection position was determined using the conventional method, and the tilt of the wafer surface was calculated. The average value of the angles in each coordinate direction of the calculated tilt and the reproducibility 3σ were then calculated. Note that the two-dimensional profiles used were those that had undergone background processing.

[0067] In the method of the present invention, the reproducibility 3σ of the angle of the calculated wafer tilt in each coordinate direction was 0.00063° in the x-coordinate direction and 0.00093° in the y-coordinate direction. On the other hand, in the conventional method, the reproducibility 3σ of the angle of the calculated wafer tilt in each coordinate direction was 0.00070° in the x-coordinate direction and 0.00100° in the y-coordinate direction.

[0068] As a result of the above findings, it was confirmed that the method of the present invention can calculate the slope even for samples in which surface diffraction is not observed, and that its accuracy is as high as that of conventional methods.

[0069] Based on the above results, it has been confirmed that the analytical apparatus, system, method, and program for analyzing the inclination of a sample surface according to the present invention can calculate the inclination even for samples in which surface diffraction is observed, and that the accuracy is sufficiently high. Furthermore, it has been confirmed that the inclination can be calculated even for samples in which surface diffraction is not observed, and that it can be used while ensuring the same level of accuracy as conventional methods.

[0070] It goes without saying that the present invention is not limited to the embodiments described above. The scope of the present invention extends to various variations and equivalents included in the technical concept of the present invention. Furthermore, the names, structures, shapes, numbers, positions, sizes, etc., of the components shown in each drawing are for illustrative purposes only and may be changed as appropriate.

[0071] The functions of the elements disclosed herein may be implemented using circuits or processing circuitry that include general-purpose processors, special-purpose processors, integrated circuits, ASICs (Application Specific Integrated Circuits), FPGAs (Field Programmable Gate Arrays), conventional circuits, and / or combinations thereof that are programmed using one or more programs stored in one or more memories, or otherwise configured to perform the disclosed functions. A processor is considered a circuit or processing circuitry because it includes transistors and other circuits. A processor may be a programmed processor that executes programs stored in memory. In this disclosure, a circuit, unit, or means is hardware that performs the enumerated functions, or hardware programmed to perform the enumerated functions. Hardware may be any hardware disclosed herein that is programmed or configured to perform the enumerated functions.

[0072] 10 System 100 X-ray analyzer 110 X-ray generator 120 Incident optical unit 130 Goniometer 140 Sample stage 150 Exit optical unit 160 Detector 200 Autocollimator 300 Control device 310 Control unit 320 Device information storage unit 330 Measurement data storage unit 340 Display unit 400 Analysis device 410 Two-dimensional profile acquisition unit 420 Line profile generation unit 430 Reflection position determination unit 440 Tilt calculation unit 510 Input device 520 Display device

Claims

1. An analytical apparatus for analyzing the inclination of a sample surface, comprising: a two-dimensional profile acquisition unit that acquires a two-dimensional profile by detecting laser light reflected or diffracted from the sample surface; a line profile generation unit that generates a first line profile and a second line profile obtained by integrating a predetermined region in a direction perpendicular to the first line and a predetermined region in a direction perpendicular to the second line, with respect to a first line in which a plurality of peaks are arranged linearly and a second line perpendicular to the first line and also arranged linearly, with respect to a predetermined region that includes at least a part of the first line and the second line, respectively; a reflection position determination unit that determines the reflection position of the two-dimensional profile based on the first line profile and the second line profile; and a slope calculation unit that calculates the inclination of the sample surface based on the reflection position of the two-dimensional profile.

2. The analytical apparatus according to claim 1, characterized in that the lengths of the first linear direction and the second linear direction of the predetermined region are 10 times or more the full width at half maximum of the peak having the maximum peak intensity among the plurality of peaks.

3. The analysis apparatus according to claim 1, characterized in that the predetermined region is the largest rectangle included in the two-dimensional profile.

4. The analysis apparatus according to claim 1, characterized in that the line profile generation unit generates the first line profile or the second line profile by subtracting a background value that is set in advance or determined based on the two-dimensional profile from the integral value when generating the first line profile or the second line profile.

5. The analysis apparatus according to claim 1, wherein the two-dimensional profile generated by the line profile generation unit is a two-dimensional profile rotated such that the direction of the first straight line and the direction of the second straight line are in predetermined directions, and the reflection position determination unit determines the reflection position of the two-dimensional profile before rotation based on the center and angle of rotation.

6. A system comprising: an X-ray analyzer comprising an X-ray generating unit for generating X-rays, a detector for detecting X-rays, and a sample stage for controlling the rotation of a sample; an autocollimator for generating the two-dimensional profile by irradiating the surface of a sample placed on the sample stage with laser light; and the analysis apparatus according to any one of claims 1 to 5.

7. A method for analyzing the inclination of a sample surface, comprising: the steps of: obtaining a two-dimensional profile by detecting laser light reflected or diffracted by the sample surface; generating a first line profile and a second line profile by integrating a predetermined region in a direction perpendicular to the first line and a predetermined region in a direction perpendicular to the second line, with respect to a first line in which a plurality of peaks are arranged linearly and a second line perpendicular to the first line and a plurality of peaks are arranged linearly, with respect to a predetermined region that includes at least a part of the first line and the second line, respectively; determining the reflection position of the two-dimensional profile based on the first line profile and the second line profile; and calculating the inclination of the sample surface based on the reflection position of the two-dimensional profile.

8. A program for analyzing the inclination of a sample surface, characterized in that it causes a computer to perform the following steps: a process of acquiring a two-dimensional profile by detecting laser light reflected or diffracted from the sample surface; a process of generating a first line profile and a second line profile by integrating in a direction perpendicular to the first line and in a direction perpendicular to the second line, with respect to a first line in which a plurality of peaks are arranged linearly and a second line perpendicular to the first line, with respect to a region that includes at least a part of each of the first and second lines as a predetermined region; a process of determining the reflection position of the two-dimensional profile based on the first line profile and the second line profile; and a process of calculating the inclination of the sample surface based on the reflection position of the two-dimensional profile.

Images