Apparatus and method for measuring pattern uniformity and method for manufacturing masks

Abstract

An apparatus and method for measuring pattern uniformity are provided, as well as a method for fabricating a mask using the measurement method. The measuring apparatus includes a light source configured to generate and output light, a platform configured to support a measurement target, an optical system configured to transmit light output from the light source to the measurement target supported on the platform, and a first detector configured to detect light reflected and diffracted by the measurement target or light diffracted through the measurement target, wherein the first detector is configured to detect a pupil image of a pupil plane and measure the pattern uniformity of an array region of the measurement target based on the intensity of at least one of zero-order and first-order light in the pupil image.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2020-0083673, filed on July 7, 2020, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention relates to measuring devices and methods, and more specifically, to measuring devices and methods based on pupil images. Background Technology

[0004] Recently, in semiconductor manufacturing processes, design rules have been continuously shrinking, resulting in a gradual reduction in pattern size. Furthermore, for measurement devices used to measure patterns on wafers or masks, resolution issues may arise due to the reduced pattern size, potentially leading to decreased measurement accuracy. To address these issues, methods to improve optical resolution are continuously being researched and developed. Methods to enhance optical resolution include achieving shorter wavelengths and achieving high numerical aperture (NA). Achieving shorter wavelengths may have limitations due to potential light insufficiency. Additionally, achieving high NA may be physically limited in terms of increasing objective lens size. Summary of the Invention

[0005] The present invention provides an apparatus and method for measuring pattern uniformity (which can accurately measure the uniformity of a pattern in an array region of a measurement target) and a method for manufacturing a mask using the measurement method.

[0006] According to an aspect of the present invention, an apparatus for measuring pattern uniformity based on a pupil image is provided. The apparatus includes a light source configured to generate and output light, a platform configured to support a measurement target, an optical system configured to transfer light output from the light source to the measurement target supported on the platform, and a first detector configured to detect light reflected and diffracted by the measurement target or light diffracted through the measurement target, wherein the first detector is configured to detect a pupil image of a pupil plane, and based on the zero-order light and first-order light of the pupil image... st -order) The intensity of at least one of the light sources is used to measure the pattern uniformity of the array region of the target.

[0007] According to another aspect of the present invention, an apparatus for measuring pattern uniformity based on a pupil image is provided. The apparatus includes a light source configured to generate and output light, a platform configured to support a mask, an optical system including a beam splitter configured to split the light into a first light and a second light, a first detector configured to detect the first light after it has been reflected and diffracted by the mask, or to detect the first light after it has been diffracted by passing through the mask, and a second detector configured to detect the second light. The optical system is configured to transmit the first light to the mask. Each of the first and second detectors is configured to detect a pupil image on a pupil plane, and the first detector is configured to measure the pattern uniformity of an array region of the mask based on the intensity of at least one of the zero-order and first-order light in the pupil image.

[0008] According to another aspect of the present invention, a method for measuring pattern uniformity based on a pupil image is provided. The method includes: generating and outputting light using a light source; transmitting the light from the light source to a measurement target disposed on a platform using an optical system; detecting light reflected and diffracted by the measurement target or light diffracted by passing through the measurement target using a first detector; and measuring the pattern uniformity of an array region of the measurement target based on the light detected by the first detector. The detection of light includes detecting a pupil image of a pupil plane using the first detector, and the measurement of pattern uniformity includes measuring the pattern uniformity based on the intensity of at least one of zero-order light and first-order light in the pupil image.

[0009] According to another aspect of the present invention, a method for manufacturing a mask is provided, the method comprising preparing a mask having an array region, generating and outputting light using a light source, transmitting the light from the light source to the mask disposed on a platform using an optical system, detecting light reflected and diffracted by the mask or light diffracted through the mask using a first detector, and measuring the pattern uniformity of the array region based on the light detected by the first detector, wherein the detection of light comprises detecting a pupil image of a pupil plane using the first detector, and performing the measurement of pattern uniformity based on the intensity of at least one of zero-order light and first-order light in the pupil image. Attached Figure Description

[0010] Embodiments of the present invention will become clearer from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0011] Figure 1 This is a block diagram of a measuring apparatus for measuring pattern uniformity based on pupil images, according to an embodiment.

[0012] Figure 2 To show in more detail Figure 1A block diagram of the illumination formation system (IFS) in the measuring device;

[0013] Figure 3A and Figure 3B It is a conceptual diagram used to describe the relationship between the spacing of patterns and the diffraction angle of diffracted light in the patterns;

[0014] Figure 4A and Figure 4B This is a conceptual diagram showing the shape of the array region included in a single shot of the first detector;

[0015] Figure 5A It is shown that... Figure 4A A photograph of an image (i.e., a pupil image) corresponding to the shape of the array region and the pupil plane. Figure 5B It is shown that... Figure 4B A photograph of the image (i.e., the pupil image) corresponding to the shape of the array region of the pupil plane;

[0016] Figure 6A and Figure 6B They are shown separately. Figure 5A and 5B A graph showing the intensity of the pupil image;

[0017] Figure 7 It is used to describe the use of Figure 1 A diagram illustrating a method for determining pattern uniformity using a measuring device;

[0018] Figure 8A and Figure 8B It is used to describe the use of Figure 1 A photograph of a method for correcting / compensating light fluctuations using a second detector of a measuring device;

[0019] Figure 9 and Figure 10 This is a block diagram of a measuring apparatus for measuring pattern uniformity based on pupil images, according to an embodiment.

[0020] Figures 11A to 11D This is a flowchart illustrating a measurement method for measuring pattern uniformity based on pupil images according to an embodiment; and

[0021] Figure 12 This is a simple illustration of the use of embodiments. Figure 11A The flowchart shows the measurement method used to manufacture the mask. Detailed Implementation

[0022] In the following description, embodiments will be described in detail with reference to the accompanying drawings. The same reference numerals refer to the same elements, and repeated descriptions of them are omitted.

[0023] Figure 1 This is a block diagram of an apparatus 1000 for measuring pattern uniformity based on pupil images, according to an embodiment.

[0024] refer to Figure 1 The apparatus 1000 (hereinafter referred to as the measuring apparatus) for measuring pattern uniformity based on a pupil image according to an embodiment can be an apparatus for measuring the uniformity of a pattern in an array region of a measurement target 2000. The measuring apparatus 1000 according to an embodiment may include a light source 100, an optical system 200, a platform 300, a detection unit 400, and an advanced illumination unit (AIU) 500. The pupil image in this disclosure can be an image representing diffracted light, which includes information about the zero-order and first-order diffracted light. The pupil image can refer to an image formed based on light that passes through an aperture and then does not pass through a condenser lens (e.g., a focusing lens or collimator).

[0025] Light source 100 may be a device that generates and outputs light L. The light L from light source 100 may include or may be a laser. The laser output from light source 100 may include or may be a pulsed laser, and for example may include or may be a laser with a pulse width of approximately 500 Hz to approximately 1 kHz. The light L from light source 100 is not limited to a pulsed laser. Furthermore, the pulse width of the pulsed laser is not limited to this value. For example, according to an embodiment, the light L from light source 100 may include or may be a continuous-wave laser.

[0026] Terms such as “approximately” or “about” can reflect quantities, sizes, orientations, or layouts that vary only in a relatively small way and / or in a way that does not significantly alter the operation, function, or structure of a particular element. For example, a range from “approximately 0.1 to approximately 1” could include ranges such as 0% to 5% deviations near 0.1 and 0% to 5% deviations near 1, especially if such deviations maintain the same effect as the listed ranges.

[0027] Light source 100 can generate and output light with various wavelengths. For example, light source 100 can generate and output light with wavelengths of approximately 200 nm (such as 248 nm (KrF), 193 nm (ArF), or 157 nm (F2)). For example, a laser beam can have wavelengths between 150 nm and 250 nm. The wavelength of the light L from light source 100 is not limited to these wavelengths. For example, light source 100 can generate and output extreme ultraviolet (EUV) light corresponding to tens of nanometers.

[0028] Optical system 200 can transmit light L output from light source 100 to measurement target 2000. Optical system 200 may include illumination forming system (IFS) 210, beam splitter (BS) 220, polarization control module (PCM) 230 and high numerical aperture (NA) (high NA, HNA) condenser 240.

[0029] IFS 210 may include various elements, and IFS 210 can shape the light L output from light source 100 into a suitable shape and can transmit the shaped light L to beam splitter 220. For example, based on the size or shape of the pattern in the array region of measurement target 2000, IFS 210 can shape the light into a shape that optimally measures the pattern uniformity and can transmit the shaped light to beam splitter 220. (Refer to...) Figure 2 The components of IFS 210 are described in more detail.

[0030] Beam splitter 220 can split the light L output from IFS 210 into two beams. For example, beam splitter 220 can split the light L output from IFS 210 into a first beam L1 and a second beam L2. Figure 1 As shown, beam splitter 220 can reflect a portion of the light L from IFS 210 to allow the first light L1 to illuminate the measurement target 2000, and can transmit another portion of the light L to allow the second light L2 to illuminate the second detector 400-2.

[0031] PCM 230 can control the polarization state of the first light L1 by using a polarization filter. For example, by using a polarization filter, PCM 230 can polarize the first light L1 by performing polarization (such as linear polarization, circular polarization, or elliptical polarization). For example, PCM 230 can polarize the first light L1 to have a polarization direction. In some embodiments, PCM 230 may be positioned between IFS 210 and beam splitter 220. In certain embodiments, PCM 230 may be omitted.

[0032] HNA condenser 240 may include an objective lens for focusing light and may have a high NA of 1 or higher. For example, HNA condenser 240 may converge a first light L1 and illuminate the measured target 2000 with the converged first light L1. According to embodiments, a medium NA (MNA) condenser with an NA of less than 1 may be provided. For example, in some embodiments, the measuring device 1000 may include an MNA instead of... Figure 1 The HNA. In a particular embodiment, the HNA concentrator 240 and the MNA concentrator may be provided together (e.g., arranged in series along the optical path of the first light L1).

[0033] The measurement target 2000 can be mounted on the platform 300. The platform 300 can support and fix the measurement target 2000. The measurement device 1000 according to the embodiment may include, for example, a transmission measurement device, which measures light diffracted through the measurement target 2000. Therefore, the platform 300 can support and fix the side surfaces and / or edge portions of the measurement target 2000. The platform 300 may include, or be, a three-dimensional (3D) moving platform capable of three-dimensional movement. As the platform 300 moves, the measurement target 2000 can move with it. For example, based on the movement of the platform 300, focusing relative to the Z-axis or scanning relative to the XY plane can be performed on the measurement target 2000. For example, the measurement target 2000 can be detected by a full scan of the entire surface of the measurement target 2000. Here, the Z-axis may correspond to the optical axis of the first light L1, and the XY plane may correspond to a plane perpendicular to the optical axis of the first light L1.

[0034] The measurement target 2000 may include a device, such as a mask or wafer, in which an array region includes multiple repeating patterns. For example, the array region may include an array of repeating patterns. For example, in the measurement apparatus 1000 according to an embodiment, the measurement target 2000 may include a mask in which an array region includes multiple repeating patterns, or may be a mask in which an array region includes multiple repeating patterns. Therefore, the measurement apparatus 1000 according to an embodiment may include means for measuring the uniformity of patterns in an array region of a mask, or may be means for measuring the uniformity of patterns in an array region of a mask.

[0035] The detection unit 400 may include a first detector (DT1) 400-1 and a second detector (DT2) 400-2. According to an embodiment, the detection unit 400 may include only the first detector 400-1.

[0036] The first detector 400-1 can detect the light generated when the first light L1 is diffracted as it passes through the measurement target 2000. For example, the first light L1 may be diffracted after passing through the measurement target 2000, and the detector 400-1 can detect the diffracted light. In the measurement apparatus 1000 according to the embodiment, the first detector 400-1 can detect the image (i.e., the pupil image) at the pupil plane PP1 corresponding to the diffracted light. Figure 1 In the diagram, the pupil plane PP1 corresponding to the diffracted light is shown by a dashed line. In the measuring apparatus 1000 according to the embodiment, the first detector 400-1 can directly detect the pupil image, thus eliminating the need for a separate condenser lens for converging the diffracted light. The first detector 400-1 may include, for example, a charge-coupled device (CCD) or a photomultiplier tube (PMT), or may be, for example, a charge-coupled device (CCD) or a photomultiplier tube (PMT). The first detector 400-1 is not limited to the above-described devices. The pupil plane in this disclosure may be corresponding to, for example, Figure 9 and Figure 10 The plane shown is the incident surface of the photodetector on which the light intensity is detected. The pupil plane can refer to the plane on which the pupil image is received. For example, a pupil image can be created after light passes through the HNA condenser 240, where the light can be diffracted by passing through the measurement target 2000. The image received at the pupil plane (e.g., at a detector arranged on this plane) (such as PP1) can be described as a pupil image.

[0037] like Figure 1As shown, light passing through the measurement target 2000 can be diffracted based on the pattern of the measurement target 2000. The diffracted light passing through the measurement target 2000 (i.e., the diffracted light DL) can include multiple high-order lights on the periphery and a zero-order light at the center. Figure 1 For convenience, only zero-order and first-order light are shown in the diagram. In multiple higher-order light (e.g., first-order light), the diffraction angle (i.e., the diffraction angle) can vary based on the size or spacing of the pattern of the measurement target 2000 (see [reference]). Figure 3A (θd1). The following will refer to... Figure 3A and Figure 3B To describe an example in more detail, the diffraction angle of first-order light varies based on the size or spacing of the pattern.

[0038] In the measuring apparatus 1000 according to the embodiment, the first detector 400-1 can be moved on a horizontal plane perpendicular to the optical axis of the diffracted light DL. The first detector 400-1 can be moved so that when the diffraction angle of each of the first-order or higher-order lights is large, the first detector 400-1 can be moved to sufficiently detect the pupil image of the array region of the measuring target 2000.

[0039] In the measuring apparatus 1000 according to the embodiment, the first detector 400-1 can have a relatively small size per image. For example, the first detector 400-1 can have a size of approximately 40 μm * 40 μm per image. However, the size of the first detector 400-1 per image is not limited to 40 μm * 40 μm. For example, the size of the first detector 400-1 per image can be 1000 μm. 2 and 2000μm 2 Between. As described above, in the measuring device 1000 according to the embodiment, the size of a single shot of the first detector 400-1 can be reduced to a small size, thereby improving the accuracy of measuring pattern uniformity.

[0040] To provide a description of reducing the size of a single image captured by the first detector 400-1, when measuring pattern uniformity, before measuring pattern uniformity based on analysis of the captured image, it must be determined whether the image contains only the array region or both array and non-array regions. Here, the array region can represent a region containing the same repeating pattern, and the non-array region can represent a region that does not contain a pattern or a region containing a pattern different from the pattern in the array region, and can be the opposite concept to the array region. For example, the array region can be a region containing an array of repeating patterns, and the non-array region can be a blank region containing irregular patterns and / or no patterns at all.

[0041] Methods primarily used to determine whether signals from non-array regions are included in an image can be implemented after the corresponding image is captured, for example, by filtering by location to identify portions with large intensity variations (e.g., greater than a predetermined value / difference). For instance, when only signals from array regions are included in a single image, the intensity variation in the image corresponding to that single image is small (e.g., it only varies less than a predetermined value / difference). However, when signals from non-array regions are included in a single image, portions with large intensity variations (e.g., it varies greater than a predetermined value / difference) may exist in the image corresponding to that single image. However, recently, with the gradual miniaturization of pattern sizes, patterns may exhibit subtle variations between array and non-array regions, and therefore, the intensity differences may not be large enough to be distinguishable in the image. As a result, signals from non-array regions may not be removed when measuring pattern uniformity and may act as noise. For example, measurement accuracy may decrease due to the reduced pattern size.

[0042] In measurement devices in related fields, the size of a single image is approximately 180 μm x 90 μm, which may be too large to measure pattern uniformity. Therefore, the likelihood of noise inclusion when measuring pattern uniformity is high. For example, because of the large size of the single image, there is a high probability that signals from non-array regions will be included in the single image. Furthermore, as mentioned above, as patterns become smaller, images including non-array regions may not be removed and may be used to measure pattern uniformity. Consequently, signals from non-array regions may act as noise, leading to erroneous results in the measurement of the uniformity of the array pattern. As a result, in measurement devices in related fields, the accuracy of measuring pattern uniformity may be low due to the relatively large size of the single image.

[0043] On the other hand, in the measuring apparatus 1000 according to this embodiment, the size of a single image captured by the first detector 400-1 can be approximately 40 μm * 40 μm, and can be 1 / 10 or less of the size of a single image captured by measuring apparatuses in the related art. Therefore, the possibility of noise being included when measuring pattern uniformity can be relatively reduced. As a result, in the measuring apparatus 1000 according to this embodiment, the accuracy of measuring pattern uniformity can be relatively high due to the small size of a single image captured.

[0044] However, as the size of a single image captured by the first detector 400-1 decreases, the time required to detect pupil images of all regions of the array area of ​​the measurement target 2000 using the first detector 400-1 may increase. Therefore, the following methods for reducing time can be applied to the measurement apparatus 1000 according to this embodiment. The first method can be a method of constructing a focus map. For example, a focus map can be constructed, and the pupil image can be detected by automatically adjusting the focus based on the focus map, thereby significantly reducing the time required to detect the pupil image. For example, the focus map can be a graph including information about the focusing distance from the first detector 400-1 at a corresponding position on the measurement target 2000. Reference will be made below. Figure 11D The process of constructing the focus map is described in more detail. A second method could be to detect pupil images only at predetermined locations corresponding to the array region of the measurement target 2000, rather than detecting pupil images corresponding to all regions of the array region of the measurement target 2000, through sampling. Considering that tens of thousands to hundreds of thousands of images need to be taken to obtain pupil images corresponding to all regions of the array region of the measurement target 2000, the location used to obtain the pupil images can be limited to the location set only by sampling; therefore, the time used to detect the pupil images can be significantly reduced.

[0045] The measuring apparatus 1000 according to this embodiment can detect the pupil image using the first detector 400-1, select a pupil image that includes only the array region using an on-off selection method, and use the selected pupil image when measuring pattern uniformity, thereby further improving the accuracy of measuring pattern uniformity. For example, the on-off selection method can be a method that sets a reference boundary for a category, with one side of the boundary inside the category (on) and the other side outside the category (off). Reference will be made below. Figures 4A to 6B The operation and on / off selection method for detecting the pupil image are described in more detail.

[0046] The second detector 400-2 can detect the second light L2 from the beam splitter 220. The second detector 400-2 can also detect the image (i.e., the pupil image) corresponding to the pupil plane PP2 of the second light L2. Figure 1In the diagram, the pupil plane PP2 corresponding to the second light L2 is shown by a dashed line. For example, the second detector 400-2 may include a CCD or a PMT. However, the second detector 400-2 is not limited to a CCD or a PMT. The second detector 400-2 can directly detect the second light L2 from the beam splitter 220 to sense fluctuations in the second light L2 in real time. For example, the second detector 400-2 can sense changes in laser power in real time. The fluctuation information about the light (e.g., emitted from the light source 100) obtained by the second detector 400-2 can be used to correct / compensate pattern uniformity and / or the pupil image obtained by the first detector 400-1. Reference will be made below. Figure 8A and Figure 8B The operation of detecting light fluctuations using the second detector 400-2 and the operation of correcting / compensating pattern uniformity and / or pupil image using information about light fluctuations are described in more detail. According to some embodiments, the second detector 400-2 may be omitted when the light emitted from the light source 100 is uniform and therefore has almost no fluctuations.

[0047] AIU 500 can be positioned between light source 100 and IFS 210. AIU 500 can delay the pulsed laser to increase the energy of the light incident on IFS 210. As a result, AIU 500 can increase the energy of the light illuminating the measurement target 2000, thereby achieving high magnification measurement. According to a particular embodiment, AIU 500 can be omitted.

[0048] According to this embodiment, the measuring device 1000 can detect the pupil image of the pattern of the array region of the measuring device 2000 using a first detector 400-1, which has a small size (e.g., has the size described above) in a single capture, and can determine the pattern uniformity based on the intensity of the pupil image, thereby measuring the pattern uniformity of the array region of the measurement target 2000 with high accuracy. Furthermore, based on the switch selection method, the measuring device 1000 according to this embodiment can select a pupil image that includes only the array region, and can use the selected pupil image when measuring pattern uniformity or extracting data, thereby improving the accuracy of measuring pattern uniformity. Furthermore, the measuring device 1000 according to this embodiment can obtain information about light fluctuations using a second detector 400-2, and can correct / compensate for pattern uniformity and / or the pupil image obtained by the first detector 400-1, thereby improving the accuracy of measuring pattern uniformity. For example, the switch selection method can be executed by hardware / software (e.g., by a computer including a processor, etc.).

[0049] Figure 2 To show in more detail Figure 1 A block diagram of IFS 210 in the measuring device 1000. Referring below... Figure 1 and Figure 2 Describe IFS 210, and briefly give or omit the above references. Figure 1 The given description.

[0050] refer to Figure 2 The IFS 210 may include a beam steering module (BSM) 211, an attenuation wheel (AW) 212, a speckle reduction module (SRM) 213, a beam homogenizer module (BHM) 214, an NA & σ wheel 215, and a zoom adapter (ZA) 216. The BSM 211 performs the function of adjusting the focus of the light. The AW 212 performs the function of adjusting the attenuation of the light. The SRM 213 performs the function of removing speckle (such as interference points) from the light (e.g., laser). The BHM 214 performs a filtering function to retain only light with the same wavelength. The NA & σ wheel 215 performs the function of adjusting the shape and size of the aperture. The ZA 216 adjusts the focus of the light.

[0051] In the measuring device 1000 according to this embodiment, the IFS 210 may include all of the above-described components. However, according to some embodiments, the IFS 210 may not include some of the above-described components. According to a particular embodiment, the IFS 210 may also include components other than those described above.

[0052] Figure 3A and Figure 3B It is a conceptual diagram used to describe the relationship between the spacing of the pattern and the diffraction angle of the diffracted light diffracted by the pattern, and each shows the pattern of the measurement target, the incident light, and the shape of the diffracted light after transmission.

[0053] refer to Figure 3A and Figure 3B The incident light Li can be incident on the measurement target 2000 and can be diffracted by passing through the measurement target 2000. The diffracted light passing through the measurement target 2000 (i.e., the diffracted light) can include zero-order light at the center and first-order light (-1, +1) on both sides relative to the zero-order light. The diffracted light can include second-order light or higher-order light. However, in the measurement device 1000 according to this embodiment, second-order light and higher-order light may not be used to measure pattern uniformity, therefore... Figure 3A and Figure 3B The term is omitted and not shown. In the following text, for example, the operation of measuring pattern uniformity using zero-order light and first-order light (-1, +1) will be described.

[0054] Figure 3A The pattern of the measurement target 2000 can have a first spacing P1, and Figure 3B The pattern of the measurement target 2000a can have a second spacing P2. The first spacing P1 can be greater than the second spacing P2. Figure 3A In the equation, the diffraction angle of a first-order light beam (-1, +1) can have a first diffraction angle θd1, and... Figure 3B In this context, the diffraction angle of a first-order light (-1, +1) can have a second diffraction angle θd2. Here, the diffraction angle (-1, +1) of a first-order light can be defined as the angle between the direction of propagation of the first-order light (-1, +1) and the optical axis.

[0055] Typically, in light diffracted by a pattern with a specific shape (e.g., a pattern with both linear and spatial shapes, such as a stripe pattern), the diffraction angle of the first-order light (-1, +1) increases as the pattern spacing decreases. Therefore, as... Figure 3A and Figure 3B As shown, the first diffraction angle θd1 of the first-order light (-1, +1) in the measurement target 2000, which includes the pattern of the first spacing P1, can be smaller than the second diffraction angle θd2 of the first-order light (-1, +1) in the measurement target 2000a, because the second spacing P2 is smaller than the first spacing P1.

[0056] Therefore, it is possible to determine whether a single image contains only the array region or includes both the array region and the region outside the array region (i.e., the non-array region) based on the variation of the diffraction angle of the diffracted light (e.g., first-order light) according to the size or spacing of the pattern. For example, in an array region where a single image includes a uniform pattern, the diffracted light (e.g., first-order light) may only include a specific diffraction angle. On the other hand, when a single image includes both array and non-array regions, first-order light outside a specific diffraction angle range can be generated.

[0057] Reference Figures 4A to 6B The switch selection method is described in more detail, which selects an array-only pupil image by determining whether a single shot includes only the array region or includes both the array region and a non-array region.

[0058] Figure 4A and Figure 4B This is a conceptual diagram showing the shape of the array region included in a single shot of the first detector. Figure 4A An example is shown in which only the array region is included in a single shot, and Figure 4B An example is shown that includes both array and non-array areas in a single shot.

[0059] refer to Figure 4A and Figure 4B ,exist Figure 4AIn a single shot, only the array region Aarr may be included, and for example, a uniform pattern with linear and spatial shapes may be included in the array region Aarr. Figure 4B In this process, the array region Aarr and non-array regions (e.g., the outer region Aout) can be included in a single shot. Like... Figure 4A Similar to the array region Aarr, uniform patterns with linear and spatial shapes can be included within the array region Aarr. However, as... Figure 4B As shown, the outer region Aout does not include the pattern.

[0060] Figure 5A It shows the corresponding Figure 4A A photograph of the shape of the array region's pupil plane (i.e., the pupil image), and Figure 5B It shows the corresponding Figure 4B A photograph of the shape of the pupil plane of the array region (i.e., a pupil image). Figure 5A and 5B In this diagram, the X and Y axes represent position, and the units of the X and Y axes are arbitrary units (au).

[0061] refer to Figure 5A , Figure 5A It corresponds to Figure 4A The image shows the shape of the pupil in the array region, and clearly shows that the zero-order light (the circle in the center) and the two first-order lights (both circles on the outside) are distinct circles. This is likely because they correspond to... Figure 4A A single shot only includes the array region Aarr, therefore, the diffracted light (i.e., first-order light) only has a specific diffraction angle.

[0062] refer to Figure 5B , Figure 5B It corresponds to Figure 4B The image shows the shape of the pupil in the array region, and reveals that the zero-order light (its central circle) and two first-order lights (two outer circles) are in a blurred shape extending in the X-axis direction. This may be because it corresponds to... Figure 4B A single shot includes an array region Aarr and an outer region Aout; therefore, the diffracted light (i.e., first-order light) also has diffraction angles in addition to specific diffraction angles. For example, when the shot includes an irregular pattern, the first-order diffracted light can have multiple diffraction angles and / or can have blurred boundaries.

[0063] Figure 6A and Figure 6B They are shown separately. Figure 5A and Figure 5B A graph showing the intensity of the pupil image. Figure 6A and Figure 6B In the diagram, the X-axis represents position, the Y-axis represents intensity, and the units of the X-axis and Y-axis are arbitrary.

[0064] refer to Figure 6A The intensity of the zeroth-order light at the center is likely to be the highest, while the intensity of the first-order light on both sides may be lower than that of the zeroth-order light. Furthermore, the intensities of the first-order light on both sides can be approximately the same. For example... Figure 6A As shown, zero-order light can be clearly distinguished from several first-order light. For example, the boundary between the zero-order and first-order light in diffraction can be clear.

[0065] When referring to orientation, layout, location, shape, size, composition, quantity, or other measures herein, the terms used herein (such as “identical,” “equal,” “planar,” or “coplanar”) do not necessarily mean exactly the same orientation, layout, location, shape, size, composition, quantity, or other measures, but are intended to include substantially identical orientations, layouts, locations, shapes, sizes, compositions, quantities, or other measures, within acceptable variations that may occur, for example, due to manufacturing processes. Unless the context or other statement otherwise indicates, the term “substantially” may be used herein to emphasize that meaning. For example, items described as “substantially identical,” “substantially equal,” or “substantially flat” may be exactly the same, equal, or flat, or may be identical, equal, or flat within acceptable variations that may occur, for example, due to manufacturing processes.

[0066] refer to Figure 6B Similar to Figure 6A The intensity of the zeroth-order light at the center may be the highest, while the intensity of the first-order light on both sides may be lower than that of the zeroth-order light. For example... Figure 6B As shown, it can be seen that the zeroth-order light and the first-order light are not clearly distinguished. Furthermore, there is a small-intensity segment between the zeroth-order and first-order light. This small-intensity segment can correspond to... Figure 5B Several portions of first-order light diffusion. For example, portions with small intensity amplitudes can be based on first-order light with different diffraction angles.

[0067] The measuring device 1000 according to this embodiment can use a switch selection method, which selects a pupil image that includes only the array region, uses the selected pupil image when measuring pattern uniformity, and removes, for example, pupil images that include non-array regions in addition to the array region. For example, the measuring device 1000 according to this embodiment can select such... Figure 5A The pupil image shown clearly distinguishes between zero-order and first-order light, and can remove features such as... Figure 5B The pupil image shown does not clearly distinguish between zero-order and first-order light. As described above, the measuring device 1000 according to this embodiment can significantly improve the accuracy of pattern uniformity measurement by using a pupil image that includes only the array region to measure pattern uniformity.

[0068] The switching selection method is not limited to clearly distinguishing between zero-order and first-order light. For example, the pupil image can be selected based solely on either zero-order or first-order light. For instance, in a pupil image that only includes the array region, each of the zero-order and first-order light can be shown in a clear circular shape, and in a pupil image that includes both the array and non-array regions, each of the zero-order and first-order light can be shown in a shape oriented to either side (e.g., as shown in the image). Figure 5B and 6B The blurred shape of the diffusion (in the X direction) is shown. Therefore, the pupil image can be selected based on the clarity of either the zero-order light or the first-order light.

[0069] Furthermore, a pupil image switching method based on the distance between the zeroth-order and first-order beams can be used. For example, in a pupil image that only includes the array region, the distance between the zeroth-order and first-order beams can be clearly defined and can be constant. On the other hand, in a pupil image that includes both the array and non-array regions, the distance between the zeroth-order and first-order beams may not be clearly defined or may not be constant, for example, due to the blurred boundary between the zeroth-order and first-order beams. This can be achieved through... Figure 6A and 6B As seen in the diagram. For example, in Figure 6A In the diagram, zeroth-order and first-order lights can be clearly distinguished from each other; therefore, the distance between them can be defined and can be constant regardless of their intensity. On the other hand, in Figure 6B As can be seen in the diagram, zero-order light and first-order light are not clearly distinguishable from each other and are shown in a combined shape. Therefore, the distance between them is difficult to define and varies based on the magnitude of the intensity.

[0070] Figure 7 It is used to describe the use of Figure 1 A diagram illustrating a method for determining pattern uniformity using a measuring device. Figure 7 The X-axis represents position, and the unit of the X-axis can be any unit. Figure 7 The Y-axis represents the grayscale.

[0071] refer to Figure 7 The intensity of the pupil image can be represented by grayscale. For example, Figure 6A The intensity of zero-order light in the intensity diagram can be converted into, for example, Figure 7 The grayscale values ​​shown indicate that the intensity map of zero-order light can be represented by specific grayscale values. Here, the grayscale values ​​can be in the range of 0 to 255.

[0072] It is possible to obtain pupil images corresponding to various spacings and patterns that are determined to be normal (e.g., within an acceptable range), to perform intensity calculations and grayscale conversions on each pupil image, and to store the calculated intensity as a reference grayscale value Rg in, for example, the memory (not shown) of the measuring device 1000. Figure 7 In the diagram, an example of the reference grayscale value Rg is shown by a solid line. For example, the reference grayscale value Rg can be used as a reference to determine the pattern uniformity in an array region.

[0073] Therefore, the measuring device 1000 according to this embodiment can measure the uniformity of a pattern in an array region of a measurement target 2000 through the following process. First, a pupil image corresponding to the array region of the measurement target 2000 can be obtained. By determining whether the pupil image is open or closed, only pupil images with the same pattern (excluding noise—e.g., noise in non-array regions) can be extracted. The intensity of each pupil image can be calculated, and the calculated intensity can be converted into a measured grayscale value. Subsequently, uniformity can be calculated by comparing the measured grayscale value with a corresponding reference grayscale value Rg. Here, the reference grayscale value Rg can be the average value of the measured grayscale values, and a deviation (σ) value can be calculated based on the reference grayscale value Rg. For example, the deviation value can be calculated by dividing the measured grayscale value by the reference grayscale value Rg. The deviation value can be represented by a % value, and this % value can be called pattern uniformity. It can be determined whether the calculated uniformity is within an acceptable range. Pattern uniformity can be determined as normal / acceptable when the calculated uniformity is within the allowable range, and as abnormal / unacceptable when the calculated uniformity is outside the allowable range. Here, the allowable range can represent a specific range with respect to a reference uniformity, and the reference uniformity can correspond to, for example, 100%. For example, these processes can be performed by hardware / software (e.g., by a computer including a processor, etc.).

[0074] As is customary in the disclosed art, features and embodiments are described and illustrated in the specification and drawings according to functional blocks, units, and / or modules. Those skilled in the art will understand that these blocks, units, and / or modules are physically implemented by electronic (or optical) circuitry (such as logic circuits, discrete components, microprocessors, hardwired circuits, memory elements, wiring connections, etc.), which can be formed using semiconductor-based manufacturing techniques or other manufacturing techniques. Where each block, unit, and / or module is implemented by a microprocessor or the like, they can be programmed using software (e.g., microcode) to perform the various functions discussed herein, and may optionally be driven by firmware and / or software. Alternatively, each block, unit, and / or module can be implemented by dedicated hardware, or as a combination of dedicated hardware performing some functions and processors performing other functions (e.g., one or more programmed microprocessors and associated circuitry). Furthermore, each block, unit, and / or module of an embodiment can be physically separated into two or more interacting and discrete blocks, units, and / or modules without departing from the scope of the inventive concept. Furthermore, the blocks, units, and / or modules of the embodiments can be physically combined into more complex blocks, units, and / or modules without departing from the scope of the inventive concept.

[0075] According to a particular embodiment, the separate process of converting intensity to grayscale can be omitted, and pattern uniformity can be measured based on a method of comparing intensity with a pre-stored reference intensity.

[0076] Figure 8A and 8B It is used to describe the use of Figure 1 A photograph of a method for correcting / compensating light fluctuations using a second detector of a measuring device. Figure 8A It is a photograph of a bare intensity map obtained through a second detector, and Figure 8B It is a photograph of a pattern intensity map obtained through a first detector. For example, a bare intensity map could be a map of the light source intensity. For example, a bare intensity map could be an intensity map of the light distribution without obstructions between the light source and the sensing area of ​​light intensity. For example, a pattern intensity map could be a map of the diffracted light of the target being measured. Figure 8A In the images / photos, the X-axis represents the number of shots, and the Y-axis represents the number of photos taken. For example, the shots are arranged in a matrix pattern. Figure 8B In the figures / photographs, the X-axis represents position (e.g., in the X direction), the Y-axis represents position (e.g., in the Y direction), and the units of the X and Y axes are arbitrary units. References will be made below. Figure 1 describe Figure 8A and Figure 8B The diagram will be provided, and the above references will be briefly given or omitted. Figure 1 The given description.

[0077] refer to Figure 8A The second detector 400-2 can directly detect light L2 from beam splitter 220, regardless of the measurement target 2000. Therefore, the raw intensity map (e.g., the intensity map of light from the light source) can be represented by intensity based on the number of shots, regardless of the measurement target 2000. Figure 8A As shown, fluctuations in light based on a photograph (e.g., by shooting) can be checked / detected. For example, the quadrilateral portion shown by the dashed line can correspond to the part where light fluctuations occur primarily. When measuring pattern uniformity without compensating for light source fluctuations, distorted / inaccurate uniformity values ​​may be obtained.

[0078] refer to Figure 8B The first detector 400-1 can detect the light generated when the first light L1 from the beam splitter 220 is diffracted through the measurement target 2000. For example, the first detector 400-1 can detect the diffracted light diffracted by the measurement target 2000. The pattern intensity map can be associated with the pattern of the measurement target 2000 and can therefore be represented by the intensity based on the position of the measurement target 2000. For reference, the first light L1 and the second light L2 can be multiple light beams separated from the light L output from the same light source 100, and therefore can have substantially the same light fluctuations. Therefore, the light fluctuations in the bare intensity map can be substantially the same as the light fluctuations in the pattern intensity map. The bare intensity map can be unaffected by the pattern of the measurement target 2000, and therefore, the light fluctuations can be easily / immediately extracted. However, in the pattern intensity map, the pattern of the measurement target 2000 may affect the pattern intensity map, and therefore, it may not be possible to clearly determine and extract the light fluctuations. Therefore, the pattern intensity map can be corrected / compensated by reflecting the light fluctuation information obtained from the bare intensity map, and thus, a more accurate pattern intensity map can be obtained by removing the light fluctuations from it.

[0079] According to this embodiment, the measuring device 1000 can directly detect the second light L2 that has not passed through the measurement target 2000 (i.e., has not been diffracted) by using the second detector 400-2, thus obtaining information about light fluctuations in real time. Here, real time can mean the same time as the time for detecting the pupil image of the measurement target 2000 using the first detector 400-1. As a result, the measuring device 1000 according to this embodiment can obtain information about light fluctuations in real time by using the second detector 400-2, and can correct / compensate the uniformity of the pattern and / or the pupil image obtained by the first detector 400-1 based on the information about the light source fluctuations, thereby significantly improving the accuracy of measuring pattern uniformity.

[0080] Figure 9 and Figure 10 This is a block diagram of a measuring apparatus for measuring pattern uniformity based on pupil images, according to an example embodiment. In the following, it will be combined with... Figure 1 refer to Figure 9 and Figure 10 The measuring apparatus according to exemplary embodiments is described, and the foregoing references are briefly given or omitted. Figures 2 to 8B The given description.

[0081] refer to Figure 9 The function and configuration of the beam splitter 220a of the optical system 200a of the measuring device 1000a according to this embodiment may differ from those of the beam splitter 220a. Figure 1 The measuring device 1000's function and configuration. More specifically, the measuring device 1000a according to this embodiment may include a light source 100, an optical system 200a, a platform 300, a detection unit 400, and an AIU 500. The light source 100, platform 300, detection unit 400, and AIU 500 can be configured with respect to... Figure 1 The measuring device 1000 is the same as those described.

[0082] The IFS 210, PCM 230, and HNA 240 of the optical system 200a can be used with [unclear - possibly related to specific technologies or applications]. Figure 1 The optical system 200 of the measuring device 1000 shown is the same as those described. The beam splitter 220a can split the light L output from the IFS 210 into two beams (e.g., a first beam L1 and a second beam L2). Figure 9 As shown, beam splitter 220a can transmit a portion of the light L from IFS 210 to allow the first light L1 to travel to the measurement target 2000, and can reflect another portion of the light L to allow the second light L2 to travel to the second detector 400-2.

[0083] In the measuring apparatus 1000a according to this embodiment, the beam splitter 220a may have modified functions (e.g., functions different from those of the previous beam splitter). For example, the arrangement of optical elements and detectors may differ from the aforementioned embodiment of the beam splitter 220a. For example, the second detector 400-2 may be positioned in the direction and / or location where light from the light source 100 is reflected by the beam splitter 220a, and the PCM 230, HNA condenser 240, platform 300, and first detector 400-1 may be positioned in the direction and / or location where light from the light source 100 passes through the beam splitter 220a.

[0084] According to an embodiment, an additional beamsplitter may also be disposed between beamsplitter 220a and PCM 230, a third detector may detect light passing through the additional beamsplitter, and a first detector 400-1 may detect light reflected by the additional beamsplitter. Similarly, in Figure 1In the measuring device 1000, an additional beam splitter can also be disposed between the IFS 210 and the beam splitter 220. A third detector can detect the light reflected by the additional beam splitter, and the light passing through the additional beam splitter can be incident on the beam splitter 220.

[0085] refer to Figure 10 The measuring device 1000b according to this embodiment can be a reflection measuring device, and therefore can be different from... Figure 1 The measuring device 1000. More specifically, the measuring device 1000b according to this embodiment may include a light source 100, an optical system 200b, a platform 300a, a detection unit 400, and an AIU 500. The light source 100, the detection unit 400, and the AIU 500 can be configured with respect to... Figure 1 The measuring device 1000 is the same as those described.

[0086] The optical system 200b may include two beam splitters (e.g., a first beam splitter and a second beam splitter) 220-1 and 220-2, and therefore may differ from... Figure 1 The optical system 200 of the measuring device 1000. IFS 210, PCM 230, and HNA 240 may also be included in the optical system 200b and can be used with [other devices]. Figure 1 The components described in the optical system 200 of the measuring device 1000 shown are the same. The first beam splitter 200-1, one of the two beam splitters (first beam splitter 220-1 and second beam splitter 220-2), can be... Figure 1 The beam splitter 220 of the measuring device 1000 is basically the same. Therefore, the first beam splitter 220-1 can split the light L output from the light source 100 into two beams. For example, the first beam splitter 220-1 can split the light L output from the light source 100 into a first beam L1 and a second beam L2. The first beam L1 can illuminate the measuring target 2000, while the second beam L2 can illuminate the second detector 400-2.

[0087] The second beam splitter 220-2, one of the two beam splitters (first beam splitter 220-1 and second beam splitter 220-2), can be positioned between the PCM 230 and the HNA concentrator 240. The second beam splitter 220-2 can transmit the first light L1 to allow the first light L1 to illuminate the measurement target 2000, and can reflect the light reflected from the measurement target 2000 to allow the reflected light to illuminate the first detector 400-1. According to an embodiment, the second beam splitter 220-2 can reflect the first light L1 to allow the reflected first light L1 to illuminate the measurement target 2000, and can transmit the light reflected from the measurement target 2000 to allow the reflected light to illuminate the first detector 400-1, for example, unlike... Figure 10 The illustration.

[0088] The measurement target 2000 can be placed on the platform 300a, and the platform 300a can support and fix the measurement target 2000. Because the measuring device 1000b according to this embodiment is a reflective measuring device, the platform 300a can support and fix the bottom surface of the measurement target 2000. The platform 300a can be a 3D movable platform, and the measurement target 2000 can move with the platform 300a as it moves.

[0089] The first light L1 can be focused by an HNA concentrator and illuminated onto the measurement target 2000, where it is reflected. The light reflected by the measurement target 2000 can be diffracted based on a pattern included in the measurement target 2000. For example, the first light L1 can be reflected and diffracted by the measurement target 2000, and thus converted into diffracted light DL. The diffracted light DL based on reflection can include second-order or higher-order light. However, for convenience, in Figure 10 In the case of diffraction (DL), light is shown as including both zero-order and first-order light. For example, to illustrate this more simply, Figure 10 Second-order and higher-order light diffraction are omitted. Furthermore, the diffracted light DL can be incident on the first detector 400-1 via the HNA condenser 240 and the second beam splitter 220-2, but for convenience, in the elements next to the HNA condenser 240, the diffracted light DL is not shown as being split into zero-order and first-order light, and is shown as only one light (e.g., shown as a beamline).

[0090] In the measuring apparatus 1000b according to this embodiment, the first detector 400-1 can detect the pupil image of the pupil plane PP1 for the diffracted light DL by reflection. Furthermore, the second detector 400-2 can detect the pupil image of the pupil plane PP2 for the second light L2 from the first beam splitter 220-1.

[0091] Figures 11A to 11D This is a flowchart illustrating a simple measurement method for measuring pattern uniformity based on pupil images according to an embodiment. In the following, it will be combined with... Figure 1 refer to Figures 11A to 11D The measurement method according to the embodiments is described, and the above references are briefly given or omitted. Figures 1 to 10 The given description.

[0092] refer to Figure 11AIn the method for measuring pattern uniformity based on pupil images according to this embodiment (hereinafter referred to as the measurement method), firstly, in operation S110, the light source 100 can generate and output light. The light from the light source 100 may include, for example, a pulsed laser, and may have a pulse frequency of approximately 500 Hz to approximately 1 kHz, and a wavelength of approximately 200 nm. For example, the pulsed laser may have a duty cycle of 50%. The light from the light source 100 is not limited to a pulsed laser. Furthermore, the pulse width or wavelength of the pulsed laser is not limited to the values ​​described above.

[0093] Subsequently, in operation S130, light can be transmitted to the measurement target 2000 using the optical system 200. For example, light from the light source 100 can be shaped by the IFS 210 and can be reflected or transmitted by the beam splitter 220, the PCM 230 can control the polarization state, and the HNA concentrator 240 can focus the light and illuminate the measurement target 2000. For example, in the case where the light is reflected by the beam splitter 220 and illuminates the measurement target 2000, light can be transmitted to the measurement target 2000 using the optical system 200. Figure 1 The measuring device 1000, and in which light passes through the beam splitter 220 and is irradiated onto the measuring target 2000, can be used Figure 9 The measuring device 1000a.

[0094] Subsequently, in operation S150, the light diffracted by the measurement target 2000 can be detected from the pupil plane using a first detector 400-1. The first detector 400-1 may include a CCD or a PMT and can detect an image of the pupil plane corresponding to the diffracted light (i.e., a pupil image). The diffracted light may be light that has passed through and been diffracted by the measurement target 2000, or it may be light reflected and diffracted by the measurement target 2000. In the case where the diffracted light is light that has passed through and been diffracted by the measurement target 2000, the following method can be used: Figure 1 Measuring device 1000 or Figure 9 The measuring device 1000a, and in which the diffracted light is reflected and diffracted by the measuring target 2000, can be used Figure 10 The measuring device 1000b.

[0095] After detecting the pupil image, in operation S170, the pattern uniformity of the array region of the measurement target 200 can be measured. When measuring the pattern uniformity of the array region, as described above, the intensity of the pupil image can be calculated and converted into a measured grayscale value, and the measured grayscale value can be compared with a reference grayscale value Rg. By measuring the pattern uniformity as described above, the measurement method according to this embodiment can accurately measure the pattern uniformity of the array region of the measurement target 2000, and therefore can accurately determine whether the pattern uniformity of the array region of the measurement target 2000 is normal / acceptable.

[0096] refer to Figure 11B The measurement method according to this embodiment may further include the operation S160 of selecting a pupil image, and therefore may differ from... Figure 11A The measurement method. For example, the measurement method according to this embodiment can sequentially execute the operation S110 of generating and outputting light, the operation S130 of transmitting light to the measurement target 2000, and the operation S150 of detecting light from the pupil plane, and the operation can be combined with the above-mentioned measurement method. Figure 11A The operation described in the measurement method is the same.

[0097] Subsequently, in operation S160, a pupil image containing only the array region of the measurement target 2000 can be selected from multiple pupil images. For example, as referenced above... Figures 4A to 6B The method described above allows for the selection of pupil images that include only the array region, while removing pupil images that include both non-array and array regions. For example, multiple pupil images captured can be examined to select which pupil images are used to determine the pattern uniformity of the mask.

[0098] After selecting the pupil image, operation S170 for measuring pattern uniformity can be performed. Operation S170 for measuring pattern uniformity can be used in conjunction with... Figure 11A The operation S170 described in the measurement method is the same. However, in the operation S170 for measuring pattern uniformity, pattern uniformity can be measured using a pupil image that includes only the array region selected by the switch selection method.

[0099] refer to Figure 11C The measurement method according to this embodiment can correct / compensate for pattern uniformity (e.g., pattern uniformity measured by the first detector 400-1) by using the second detector 400-2, and therefore can be different from... Figure 11BThe measurement method is as follows. For example, according to the measurement method of this embodiment, operation S110 of generating and outputting light can be performed. Then, in operation S120, the light can be split into a first light L1 and a second light L2 by using a beam splitter 220. Subsequently, in operation S130a, the first light L1 can be transmitted to the measurement target 200 by using an optical system 200, and the second light L2 can be transmitted to the second detector 400-2.

[0100] Subsequently, in operation S150a, based on the first light L1, the light diffracted by the measurement target 2000 can be detected from the pupil plane by the first detector 400-1, and in operation S160, the pupil image can be selected by using a switch selection method. Operation S150a, which detects light from the pupil plane, and operation S160, which selects the pupil image, can be referenced above. Figure 11A and Figure 11B The corresponding operations described are the same.

[0101] In operation S155, based on the second light L2, the second light L2 can be detected from the pupil plane by using the second detector 400-2, and the fluctuation of the second light L2 can be sensed. In operation S157, information about the fluctuation of the second light L2 can be obtained.

[0102] Subsequently, in operation S170a, the pattern uniformity of the array region of the measurement target 2000 can be measured and corrected / compensated. The operation of measuring pattern uniformity can be combined with... Figure 11A The operation described in the measurement method is the same. The correction of pattern uniformity can be performed based on two methods. The first method can be a method that corrects / compensates the pupil image based on fluctuation information about the second light L2 and measures the pattern uniformity of the array region of the measurement target 2000 using the corrected / compensated pupil image. The second method can be a method that measures the pattern uniformity of the array region of the measurement target 2000 using the pupil image pre-stored in a database, for example, including the correlation between light fluctuations and pattern uniformity, and corrects / compensates the pattern uniformity based on the stored data using information about light fluctuations.

[0103] refer to Figure 11D In operation S101, the measurement method according to this embodiment can construct a focal map corresponding to the measurement target 2000, and therefore can be different from... Figure 11CThe measurement method according to this embodiment can construct a focus map corresponding to the measurement target 2000 before generating and outputting light in operation S101. Typically, after focusing on each of the corresponding regions, an operation to capture an image using a detector can be performed. However, in cases where tens of thousands to hundreds of thousands of images are captured due to the width of the measurement area (i.e., array area) of the measurement target 2000, each individual focus adjustment operation may take a long time to complete the capture of the entire wide measurement area of ​​the measurement target 2000. Therefore, in the measurement method according to this embodiment, a focus map corresponding to the measurement target 2000 can be constructed in advance, and then, in cases where the pupil image is detected using the first detector 400-1, focusing can be automatically performed based on the focus map, thereby omitting the individual focus adjustment process. Therefore, the time for detecting the pupil image using the first detector 400-1 can be significantly reduced. According to the embodiment, the focus map can be reflected / used in operation S170a for measuring and correcting pattern uniformity.

[0104] To reduce the time required to detect the pupil image using the first detector 400-1, in the operation S150a of detecting light from the pupil plane, the first detector 400-1 can detect the pupil image only at the location of the measurement target 2000 set by the sampling operation. For example, before the operation S101 of constructing the focus map, a sampling operation can be performed to select the location in the measurement target 2000 from which the pupil image is to be detected / obtained. Subsequently, in the operation S101 of constructing the focus map, the focus map can be constructed only at the location selected by the sampling operation.

[0105] After the operation S101 of constructing the focus map, the operations from the operation S110 of generating and outputting light to the operation S170a of measuring and correcting pattern uniformity can be combined with those for... Figure 11C The operation described in the measurement method is the same.

[0106] Figure 12 This is a simple illustration of the use of embodiments. Figure 11A The flowchart describes the method for manufacturing a mask using measurement techniques. In the following text, it will be combined with... Figure 1 refer to Figure 12 A method for manufacturing a mask according to an embodiment is described, and the foregoing references are briefly given or omitted. Figures 11A to 11D The given description.

[0107] refer to Figure 12First, in the method for manufacturing a mask according to this embodiment, a mask can be prepared in operation S201. The mask may be a measurement target 2000 and may include an array region, and multiple repeating patterns may be set in the array region. Operation S201 of preparing the mask may include a process of forming a pattern in the array region of the mask. For example, in operation S201 of preparing the mask, a pattern may be formed in the array region of the mask by processes such as a pattern design process, an optical proximity correction (OPC) process, a mask data preparation process, and an exposure process.

[0108] Subsequently, operations from generating and outputting light S210 to measuring pattern uniformity S270 can be executed sequentially. The operations from generating and outputting light S210 to measuring pattern uniformity S270 can be performed in conjunction with operations targeting… Figure 11A The operations described in the measurement method are the same. For example, the operations from generating and outputting light S210 to measuring pattern uniformity S270 can be applied to a mask.

[0109] Following operation S270, which measures the pattern uniformity, operation S280 determines whether the pattern uniformity of the array region of the mask is normal / acceptable. As described above, when the calculated uniformity is within the allowable range, the pattern uniformity can be determined as normal / acceptable, while when the calculated uniformity is outside the allowable range, the pattern uniformity can be determined as abnormal / unacceptable.

[0110] When the pattern uniformity is normal / passes (yes), subsequent processes can be performed on the mask in operation S290. Subsequent processes performed on the mask may include processes for coating a thin film on the mask and finishing processes performed on the mask. Finishing processes performed on the mask may include, for example, processes for loading and holding the mask or document processing processes for recording the completion date. The mask can be completed through subsequent processes performed on the mask.

[0111] When the pattern consistency is abnormal / failure (no), the cause can be analyzed and the process conditions can be changed in operation S285. Here, the process conditions can refer to the process conditions of the process of forming the pattern in the array region of the mask. After changing the process conditions, the mask preparation operation S201 can be performed. In the mask preparation operation S201, the changed process conditions can be applied to the process of forming the pattern in the array region of the mask.

[0112] The above has already described the basis Figure 11A The measurement method is a method for manufacturing masks, but it is not limited to this, and it can be based on... Figures 11B to 11DOne of the measurement methods is used to perform this. Furthermore, the mask manufacturing method according to this embodiment can be applied to... Figures 11A to 11D All kinds of devices for measurement methods. For example, Figures 11A to 11D The measurement method can be applied to methods for measuring the pattern uniformity of an array region of a wafer. Therefore, the mask manufacturing method according to this embodiment can be applied to semiconductor devices included in a wafer.

[0113] While the inventive concept has been specifically shown and described with reference to embodiments thereof, it should be understood that various changes in form and detail may be made without departing from the spirit and scope of the appended claims.

Claims

1. A device for measuring pattern uniformity based on a pupil image, the device comprising: a light source configured to generate and output light; a stage configured to support a measurement target; an optical system configured to deliver the light output from the light source to the measurement target supported on the stage; and a first detector configured to detect light reflected and diffracted by the measurement target or diffracted by passing through the measurement target, wherein the first detector is configured to detect a pupil image of a pupil plane and measure pattern uniformity of an array region of the measurement target based on intensity of at least one of zeroth order light and first order light of the pupil image, wherein the measurement target comprises a mask, and wherein a size of a single shot of the first detector varies for each mask based on a pattern of the array region. 2.The device of claim 1, wherein the first detector is configured to detect a pupil image corresponding to light diffracted by passing through the mask, and a size of a single shot of the first detector is 40 μm*40 μm. 3.The device of claim 2, wherein based on that a diffraction angle of diffracted light in the array region is different from a diffraction angle of diffracted light in a region other than the array region, and intensity of a first pupil image including only the array region is different from intensity of a second pupil image including at least a part of a region other than the array region, the first detector is configured to measure the pattern uniformity based on a switch selection method of selecting only the first pupil image and removing the second pupil image. 4.The device of claim 2, wherein the first detector comprises a charge-coupled device (CCD) or a photomultiplier tube (PMT), the first detector is configured to sense one of intensity of the zeroth order light, intensity of the first order light, and intensity of both the zeroth order light and the first order light, convert the sensed intensity into a gray scale, and measure the pattern uniformity of the array region based on the gray scale. 5.The device of claim 1, further comprising a second detector, wherein the optical system comprises a beam splitter configured to split the light output from the light source into first light and second light, the first light from the beam splitter is incident to the measurement target and the second light is incident to the second detector, and the second detector is configured to detect a pupil image corresponding to the second light to sense fluctuation of the second light in real time. based on information about fluctuation of the second light, the device is configured to compensate for a pupil image corresponding to the first light or compensate for the pattern uniformity.

6. The apparatus of claim 5, wherein, 7.The device of claim 1, wherein the device is configured such that: a pupil image corresponding to an entire surface of the measurement target is detected by full scanning, or a pupil image corresponding to each of set positions of the measurement target is detected by sampling. 8.The device of claim 1, wherein the device is configured such that: ​ constructing a focus map corresponding to an entire surface of the measurement target before the first detector detects light, and automatically performing focusing based on the focus map while detecting light using the first detector. 9.An apparatus for measuring pattern uniformity based on a pupil image, the apparatus comprising: a light source configured to generate and output light; a stage configured to support a mask; an optical system including a beam splitter configured to split the light into first light and second light, the optical system configured to transmit the first light to the mask; and a first detector configured to detect the first light after the first light is reflected and diffracted by the mask or to detect the first light after the first light is diffracted by passing through the mask; and a second detector configured to detect the second light, wherein each of the first detector and the second detector is configured to detect a pupil image of a pupil plane, and the first detector is configured to measure pattern uniformity of an array region of the mask based on intensity of at least one of zeroth order light and first order light of the pupil image, wherein the first detector is configured such that a size of a single shot of the first detector is based on a pattern of the array region according to mask variation. 10.The apparatus of claim 9, wherein the first detector is configured to detect a pupil image of the first light diffracted by passing through the mask, and a size of a single shot of the first detector is 40 μm*40 μm, based on that a diffraction angle of diffracted light in the array region is different from a diffraction angle of diffracted light in a region other than the array region, the apparatus is configured to determine whether the pupil image includes only the array region or includes at least a portion of the region other than the array region, and the first detector is configured to select the pupil image including only the array region, and to measure the pattern uniformity using the selected pupil image. 11.The apparatus of claim 9, wherein the second detector is configured to detect a pupil image of the second light based on information about fluctuation of the second light to sense fluctuation of the second light in real time, and the apparatus is configured to compensate for a pupil image of the first light or to compensate for the pattern uniformity. 12.The apparatus of claim 9, wherein the first detector is configured to detect a pupil image of an entire surface of the mask by full scan, or the first detector is configured to detect a pupil image of each of set positions of the mask by sampling. 13.A method for measuring pattern uniformity based on a pupil image, the method comprising: generating and outputting light by using a light source; transmitting the light from the light source to a measurement target disposed on a stage by using an optical system; detecting light reflected and diffracted by the measurement target or light diffracted by passing through the measurement target by using a first detector; and measuring pattern uniformity of an array region of the measurement target based on the light detected by the first detector, wherein ​ the detecting of the light includes detecting a pupil image of a pupil plane by using the first detector, and the measuring of the pattern uniformity includes measuring the pattern uniformity based on intensity of at least one of zeroth order light and first order light of the pupil image, wherein a size of a single shot of the first detector varies for each measurement target based on a pattern of the array region. 14.The method of claim 13, wherein the measurement target includes a mask, the first detector detects a pupil image of light diffracted by passing through the mask, and a size of a single shot of the first detector is 40 μm*40 μm, the method further includes, before the measuring of the pattern uniformity, selecting the pupil image, the selecting of the pupil image includes determining whether the pupil image includes only the array region or at least a portion of a region other than the array region based on a diffraction angle of diffracted light in the array region being different from a diffraction angle of diffracted light in a region other than the array region, and selecting the pupil image including only the array region, and the measuring of the pattern uniformity includes using the selected pupil image including only the array region in measuring the pattern uniformity. 15.The method of claim 13, wherein the transmitting of the light to the measurement target includes splitting the light into first light and second light by using a beam splitter, irradiating the first light to the measurement target, and irradiating the second light to a second detector, the detecting of the light includes detecting a pupil image of the second light by using the second detector to sense fluctuation of the second light in real time, and the measuring of the pattern uniformity includes compensating for a pupil image of the first light or compensating for the pattern uniformity based on information about fluctuation of the second light. 16.The method of claim 13, wherein the detecting of the light includes detecting a pupil image corresponding to an entire surface of the measurement target by full scanning by using the first detector, or detecting a pupil image corresponding to each of set positions of the measurement target by sampling by using the first detector. 17.The method of claim 13, further comprising, before the transmitting of the light to the measurement target, constructing a focus map corresponding to an entire surface of the measurement target, wherein the detecting of the light includes automatically performing focusing based on the focus map, or the measuring of the pattern uniformity includes reflecting the focus map in a measurement result of the pattern uniformity. 18.A method of manufacturing a mask, the method comprising: preparing a mask having an array region; generating and outputting light by using a light source; transmitting the light from the light source to the mask disposed on a stage by using an optical system; detecting light reflected and diffracted by the mask or light diffracted by passing through the mask by using a first detector; and measuring pattern uniformity of the array region based on the light detected by the first detector; wherein the detection of the light comprises detecting a pupil image of a pupil plane by using the first detector, wherein the measurement of the pattern uniformity is performed based on an intensity of at least one of zeroth order light and first order light of the pupil image, and wherein a size of a single shot of the first detector varies for each mask based on a pattern of the array region.

19. The method of claim 18, further comprising, when the pattern uniformity is abnormal, analyzing a cause thereof, changing a process condition of a process of forming the array region, and manufacturing the mask.

Images