Semiconductor measurement device

Abstract

An example semiconductor measurement apparatus includes a light source, a pattern generator, a stage, an image sensor, and a controller. The light source is configured to output light in a predetermined wavelength band. The pattern generator is configured to generate light including a speckle pattern by scattering light output from the light source. A stage is disposed on a moving path of the light including the speckle pattern, and a sample reflecting the light including the speckle pattern is disposed on the stage. The image sensor is configured to receive the light reflected from the sample and generate a raw image representing a diffraction pattern of the light reflected from the sample. The controller is configured to generate a predicted image for estimating diffraction characteristics of light incident on the image sensor.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0078222 filed in the Korean Intellectual Property Office on June 19, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to a semiconductor measuring device. Background Art

[0004] A semiconductor measurement apparatus may be an apparatus configured to measure a critical dimension of a pattern in a sample subjected to a semiconductor process, and recently, a measurement apparatus capable of not only measuring the critical dimension but also capturing an image of an actual shape of a pattern formed in the sample has been proposed.

[0005] In this way, a measuring device configured to capture an image of the actual shape of a pattern can inspect the structure and shape of the pattern in a non-destructive manner, but there may be problems in that the viewing angle and resolution may be limited, and in a trade-off relationship, it may be difficult to improve the efficiency and accuracy of the inspection operation. Summary of the invention

[0006] The present disclosure relates to a semiconductor measuring device including a semiconductor measuring device that improves both viewing angle and resolution using an image obtained by irradiating a sample with light including a speckle pattern to restore an image representing a measurement area irradiated with light from the sample.

[0007] In general, according to some aspects, the disclosed subject matter relates to a semiconductor measurement device, including: a light source configured to output light in a predetermined wavelength band; a pattern generator configured to generate light including a speckle pattern by scattering the light output from the light source; a stage disposed on a moving path of the light including the speckle pattern, and a sample reflecting the light including the speckle pattern is placed in the stage; an image sensor configured to receive light reflected from the sample and generate an original image representing a diffraction pattern of the light reflected from the sample; and a controller configured to generate a predicted image for estimating diffraction characteristics of light incident on the image sensor using a first optical model representing optical characteristics of the light including the speckle pattern and a second optical model representing optical characteristics of a measurement area for the sample reflecting the light including the speckle pattern, wherein the controller compares the predicted image with the original image and generates a result image representing the measurement area.

[0008] In general, according to some other aspects, the subject matter of the present disclosure relates to a semiconductor measurement device, including: a light source configured to output coherent light; a pattern generator configured to emit light including a plurality of plane waves moving in different directions to a sample by scattering the coherent light; a stage configured to adjust a position of the sample so that the light is reflected in a selected area that is a partial area of ​​the sample; and an image sensor configured to generate a raw image in response to the light reflected from the selected area.

[0009] In general, according to some other aspects, the subject matter of the present disclosure relates to a semiconductor measurement device, including: a speckle illumination configured to output light including a plurality of plane waves moving in different directions; a stage in which a sample for reflecting the light output from the speckle illumination is disposed; an image sensor configured to generate an original image in response to light reflected from a partial area of ​​the sample; and a controller configured to generate a predicted image for estimating a diffraction pattern of light incident on the image sensor by performing a forward propagation operation using a first optical model and a second optical model, the first optical model representing optical properties of light output by the speckle illumination and the second optical model representing optical properties of light reflected from the sample, wherein the controller is configured to perform a backward propagation operation for adjusting the first optical model and the second optical model based on a difference between the predicted image and the original image, and obtain a result image representing the partial area of ​​the sample by repeatedly performing the forward propagation operation and the backward propagation operation.

[0010] In some embodiments, coherent light is irradiated to a pattern generator to generate light including a speckle pattern, and the light including the speckle pattern is irradiated to a sample and then incident on an image sensor. Since light reflected and scattered from the pattern generator is irradiated to the sample and then incident on the image sensor, the area of ​​a region irradiated by light is increased in a single capture operation to improve the efficiency of the inspection operation. In addition, an original image generated by the image sensor is compared with a predicted image for estimating a diffraction pattern of light incident on the image sensor to generate a result image for displaying the region irradiated by light, thereby improving the accuracy of the inspection operation by improving the resolution of the result image.

[0011] The advantages and effects of the present application are not limited to the foregoing and may be more easily understood in the process of describing some embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The above and other aspects, features and advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.

[0013] Figure 1 is a diagram schematically illustrating a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0014] Figure 2 is a flowchart illustrating an inspection method using a semiconductor measurement apparatus according to an example embodiment of the present disclosure.

[0015] Figure 3 is a diagram illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0016] Figure 4 and Figure 5 is a diagram illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0017] Figure 6 is a diagram illustrating optical characteristics of a pattern generator included in a semiconductor measurement apparatus according to an example embodiment of the present disclosure.

[0018] Figure 7 is a diagram illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0019] Figure 8 is a flowchart illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0020] Fig. 9 is a diagram illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0021] Fig.10 and Fig.11 is a diagram illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0022] Fig.12 and Fig.13 is a diagram illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0023] Figures 14 to 16 is a diagram illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0024] Fig.17 and Fig.18 is a diagram illustrating a semiconductor device to which an inspection operation using a semiconductor measurement apparatus may be applied according to an example embodiment of the present disclosure. DETAILED DESCRIPTION

[0025] Hereinafter, example embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0026] Figure 1 is a diagram schematically illustrating a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0027] Reference Figure 1 , a semiconductor measurement device 10 according to an example embodiment of the present disclosure includes a light source 12, a pattern generator 13, a stage 14, an image sensor 16, and a controller 18. The light source 12 outputs light in a predetermined wavelength band, and may output light such as an extreme ultraviolet wavelength band, an ultraviolet wavelength band, and a visible wavelength band. According to an example embodiment, the light source 12 includes a plurality of light sources emitting light having different wavelength bands.

[0028] For example, when the light source 12 outputs light in the extreme ultraviolet band, the light source 12 may output extreme ultraviolet light with high energy density in the band of 13.5 nm. In this case, the light source 12 may include a plasma-based light source or a synchrotron radiation light source. A plasma-based light source refers to a light source that generates plasma and uses light emitted by the plasma, and may include a laser-generated plasma (LP) light source or a discharge-generated plasma (DPP) light source. For example, when the light source 12 includes a plasma-based light source, the light source 12 may include a condenser such as an elliptical mirror or a spherical mirror to increase the energy density of the extreme ultraviolet light.

[0029] The light output from the light source 12 may be coherent light. Figure 1 , the light source 12 may output light having high spatial coherence by aligning the wavefront. The light output by the light source 12 may be reflected and / or scattered by the pattern generator 13, and for example, the light reflected by the pattern generator 13 may include a speckle pattern. The pattern generator 13 may include at least one of a diffractive optical element, an optical lattice structure, a scattering element, and a wavefront modulator.

[0030] The light reflected by the pattern generator 13 may be incident on a sample 15 disposed on a stage 14. For example, the sample 15 may be a wafer or a mask in which a predetermined pattern is formed, and the optical characteristics of the light reflected from the sample 15 may be changed according to the shape and size of the pattern formed in the sample 15. The light reflected from the sample 15 may be incident on an image sensor 16, and Figure 1 In the example embodiment shown in , a mirror 17 may also be provided between the stage 14 in which the sample 15 is provided and the image sensor 16 .

[0031] The image sensor 16 may generate a raw image in response to light reflected from the sample 15. For example, the raw image may be an image representing a diffraction pattern of light reflected from the sample 15 and incident on the image sensor 16.

[0032] The controller 18 may control the operation of the light source 12, the stage 14, and the image sensor 16. For example, the controller 18 may control the light source 12 to output coherent light and move the stage 14 so that the light reflected and scattered by the pattern generator 13 is reflected in a specific area of ​​the sample 15. In an example embodiment, the controller 18 may specify a measurement area in the sample 15 to generate an image representing the shape of the pattern, and divide the measurement area into a plurality of unit areas. At least some of the plurality of unit areas may be defined to overlap each other, and the controller 18 may move the stage 14 so that light is irradiated to the plurality of unit areas at least once. The image sensor 16 may generate at least one original image for each of the plurality of unit areas.

[0033] The controller 18 may generate a first optical model representing optical characteristics of light emitted by the pattern generator 13 and a second optical model representing optical characteristics of a measurement area of ​​reflected light from the sample 15. The controller 18 may generate a predicted image for estimating diffraction characteristics of light incident on the image sensor by performing arithmetic operations using the first optical model and the second optical model.

[0034] When the image sensor 16 generates an original image of the measurement area irradiated with light in the sample 15, the controller 18 can adjust the first optical model and the second optical model by comparing the predicted image with the original image. For example, the initial value of each of the first optical model and the second optical model can be arbitrarily determined. The controller 18 can update the predicted image using the first optical model and the second optical model adjusted based on the comparison result of the predicted image with the original image, compare the updated predicted image with the original image, and repeat the operation of adjusting the first optical model and the second optical model.

[0035] When the adjustment operation is completed to optimize the first optical model and the second optical model, the controller 18 may use the optimized first optical model and the optimized second optical model to generate a result image representing a measurement area where light is reflected from the sample 15. The result image may be an image representing a pattern of the measurement area, and the shape and critical dimension of the pattern may be determined using the result image.

[0036] Reference Figure 1, the pattern generator 13, the stage 14, and the image sensor 16 may be disposed in the housing 11, and thus, the light output from the light source 12 may move in the housing 11. According to an example embodiment, the light source 12 may also be disposed in the housing 11. For example, the internal space of the housing 11 may be decompressed to a vacuum state by a pump 19. The pump 19 may be operated by the controller 18, and the internal space of the housing 11 may be decompressed by the pump 19 to minimize scattering by air, thereby improving the accuracy of the measurement operation. However, the operation of the pump 19 may not completely set the internal space of the housing 11 to a vacuum state without air, and, for example, the pump 19 may be operated to reduce the pressure inside the housing 11 to a predetermined reference air pressure or less.

[0037] Meanwhile, according to example embodiments, the semiconductor measuring apparatus 10 may be used in conjunction with Figure 1 The reflective type shown in FIG. 1 may be implemented in a different transmissive type. In this case, light emitted from the light source may pass through the pattern generator and may be incident on the sample, and may pass through the sample and may be incident on the image sensor.

[0038] Figure 2 is a flowchart illustrating an inspection method using a semiconductor measurement apparatus according to an example embodiment of the present disclosure.

[0039] Reference Figure 2 The inspection method according to the exemplary embodiment of the present disclosure begins with arranging a pattern generator and a sample (S10). Figure 1 In the present invention, a sample is placed on a stage, and a pattern generator is placed between the sample and a light source, thereby reflecting or transmitting light output from the light source and moving the light to the sample. A controller of the semiconductor measuring apparatus adjusts the position of the stage so that the light reflected and / or scattered from the pattern generator is irradiated to a measuring area in which a pattern to be inspected is placed.

[0040] When the sample arrangement and position adjustment of the stage are completed, the controller may control the light source so that light is output to the pattern generator (S20). The light source may output coherent light, and the pattern generator may reflect and / or scatter the coherent light to emit light including a speckle pattern. For example, the light reflected by the pattern generator includes a plurality of plane waves moving in different directions, and the plurality of plane waves may have different phases. Therefore, the light source and the pattern generator may be defined as speckle illumination.

[0041] The light reflected and / or scattered from the pattern generator may be incident on the image sensor, and the controller may obtain a raw image from the image sensor (S30). The raw image may be an image representing diffraction characteristics of the light incident on the image sensor.

[0042] For example, when the area of ​​the measurement area is too large and it is difficult to capture an image at one time with light reflected and / or scattered from the pattern generator, the controller may divide the measurement area into a plurality of unit areas, may irradiate light to each of the plurality of unit areas, and may continue to capture using the image sensor. During the capture process, the controller may determine whether scanning for the plurality of unit areas is completed (S40). When the capture operation is performed at least once for each of the plurality of unit areas, the controller may determine that the scanning is completed.

[0043] When it is determined in operation S40 that the scanning is not completed, the controller may move the stage (S50), may irradiate the sample with light again, and may obtain an original image from the image sensor (S30). Meanwhile, when it is determined in operation S40 that the scanning is completed, the controller may generate a result image (S60). As described above, the result image may be generated by comparing the original image obtained by the controller from the image sensor with the predicted image generated by the controller through an arithmetic operation.

[0044] Figure 3 is a diagram illustrating the operation of a semiconductor measuring device according to an exemplary embodiment of the present disclosure. Figure 4 and Figure 5 is a diagram illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0045] First, refer to Figure 3 , a plurality of unit areas 105 are defined in the sample 100. Each of the plurality of unit areas 105 may have an area that may irradiate light output from the speckle illumination 110 once. As described above, the speckle illumination 110 may include a light source for outputting coherent light and a pattern generator for reflecting and scattering the coherent light. Therefore, the light output by the speckle illumination 110 includes a speckle pattern and may include a plurality of plane waves moving in different directions. The plurality of unit areas 105 may be arranged in parallel with the surface of the sample 100 in the first direction D1 and the second direction D2.

[0046] like Figure 3 As shown in , each of the plurality of unit regions 105 is defined to overlap with at least one other unit region 105 in at least one of the first direction D1 and the second direction D2. Figure 4 As shown in FIG. 1 , when the speckle illumination 110 irradiates light so that at least some of the plurality of unit regions 105 overlap each other, the controller obtains a plurality of original images 200 ( 201 to 204 ) from the image sensor. For example, the number of the plurality of original images 200 may be equal to the number of the plurality of unit regions 105 .

[0047] Each of the plurality of original images 200 may be compared with each of the plurality of predicted images 210 (211 to 214). Each of the plurality of predicted images 210 may be an image predicting a diffraction pattern of light output from the speckle illumination 110 and reflected from the sample 100 to be incident on the image sensor. For example, the plurality of predicted images 210 may be generated using a first optical model representing optical characteristics of light output by the speckle illumination 110 and a second optical model representing optical characteristics of each of the unit regions 105 for reflecting light from the sample 100. Therefore, since the first optical model and the second optical model are more accurate, the difference between the plurality of predicted images 210 and the plurality of original images 200 may be reduced.

[0048] A plurality of predicted images 210 may be generated for a plurality of unit regions 105 defined in the sample 100. For example, a first predicted image 211 generated for a first unit region among the plurality of unit regions 105 may be compared with a first original image 201 generated by an image sensor when light reflected from the first unit region is incident on the image sensor. Similarly, a second predicted image 212 corresponding to a second unit region may be compared with a second original image 202 representing a diffraction pattern of light reflected from the second unit region.

[0049] The controller of the semiconductor measurement device may adjust the first optical model and the second optical model until the difference between the plurality of original images 200 and the plurality of predicted images 210 is equal to or less than a predetermined reference difference. For example, the difference between the plurality of original images 200 and the plurality of predicted images 210 may be defined by fidelity. Fidelity is a parameter indicating how similar each of the plurality of predicted images 210 is to the plurality of original images 200, and as fidelity decreases, the predicted image 210 may be similar to the original image 200.

[0050] The controller may optimize the first optical model and the second optical model by adjusting the first optical model and the second optical model until the fidelity of the original image 200 and the predicted image 210 in each of the plurality of unit regions 105 is equal to or less than a predetermined threshold. When the optimization of the first optical model and the second optical model is completed, the optimized first optical model and the optimized second optical model may be used to generate a result image representing the unit region 105 of the sample 100, and based on the result image, a pattern formed in the sample 100 may be checked.

[0051] Figure 6 is a diagram showing optical characteristics of a pattern generator included in a semiconductor measurement device according to an example embodiment of the present disclosure. Figure 7 is a diagram illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0052] Figure 6 is a diagram illustrating a phase aberration in a region where the pattern generator 300 transmits or reflects light received from a light source according to an exemplary embodiment of the present disclosure. Figure 6 , a phase difference between light incident on the pattern generator 300 and light emitted from the pattern generator 300 occurs differently depending on the position of the pattern generator 300. Therefore, light reflected from or transmitted through the pattern generator 300 includes a plurality of plane waves moving in different directions.

[0053] Figure 7 is a diagram simply showing a semiconductor measuring device 400 according to an example embodiment of the present disclosure. Figure 7 , the semiconductor measurement device 400 includes a light source 410, a pattern generator 420, a lens 430, a sample 440, and an image sensor 450. Figure 7 In the example embodiment shown in FIG. 4 , the semiconductor measuring apparatus 400 is implemented in a transmission type.

[0054] The light source 410 may output light having correlation. The light output by the light source 410 may pass through the pattern generator 420, and the light passing through the pattern generator 420 may include a plurality of plane waves moving in different directions, such as Figure 7 For example, at least some of the plurality of plane waves included in the light passing through the pattern generator 420 may have different phases.

[0055] The lens 430 may be disposed between the pattern generator 420 and the sample 440. The lens 430 may re-collect the light diffused by passing through the pattern generator 420 and move the light to the sample 440. However, according to example embodiments, the lens 430 may be omitted.

[0056] The light passing through the lens 430 may be incident on the sample 440. Figure 7 , the light passing through the lens 430 may include a first plane wave q1, a second plane wave q2, and a third plane wave q3. However, this is an example embodiment, and a greater number of plane waves may be included in the light incident on the sample 440. The light incident on the sample 440 may be defined as any combination of a plurality of plane waves (q1, q2, ..., qN) as in the following equation 1. In equation 1, α 1 , α 2 ,……,α N It can be the intensity of each plane wave.

[0057] <Equation 1>

[0058] s=α 1 q1+α 2 q2+…+αN QUR

[0059] In other words, when the light output from the light source 410 passes through the pattern generator 420, the first to third plane waves q1 to q3 moving in different directions may be incident on the sample 440. The first to third plane waves q1 to q3 moving in different directions may move in different directions even after passing through the sample 440, as shown in FIG. Figure 7 Therefore, in a single capturing operation, the image sensor 450 can receive light reflecting the optical characteristics of the sample 440 in a wider area, thereby increasing the viewing angle of the semiconductor measurement apparatus 400.

[0060] In the example embodiment, as the size of the grains included in the pattern generator 420 decreases, the difference in the moving directions of the first to third plane waves q1 to q3 increases, thereby allowing the light passing through the sample 440 to be diffused more widely. Therefore, according to the selection of the pattern generator 420, the viewing angle of the semiconductor measurement apparatus 400 can be adjusted, and the efficiency of the inspection operation using the semiconductor measurement apparatus 400 can be improved.

[0061] Reference Figure 7 , the first plane wave q1, the second plane wave q2, and the third plane wave q3 may all be incident on some of the pixels of the image sensor 450. The effective viewing angle may be determined by the region in which the pixels on which all the first plane waves q1 to the third plane waves q3 are incident are arranged. The image sensor may generate a raw image representing a diffraction pattern of light passing through the measurement region of the sample 440 based on pixel signals generated by pixels arranged in the region corresponding to the effective viewing angle, and provide the raw image to the controller of the semiconductor measurement device 400.

[0062] Figure 8 is a flowchart illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0063] Reference Figure 8 The operation of the semiconductor measuring device according to the exemplary embodiment of the present disclosure begins by allowing the controller of the semiconductor measuring device to update position information (S100). The position information updated in operation S100 is position information of the area where light is incident in the sample. As described above, the measurement area in the sample in which the pattern to be measured is formed may have a larger area that may be difficult to cover with one capture operation.

[0064] The controller may divide the measurement area into a plurality of unit areas, and may irradiate light to each of the plurality of unit areas at least once, and adjust the position of the stage on which the sample is disposed so that the image sensor may obtain an original image for each of the plurality of unit areas. In operation S100, the position information may be updated by selecting one of the plurality of unit areas.

[0065] The light incident on each of the plurality of unit areas may be light output from the light source, reflected from the pattern generator, and then incident on the sample. The light source may output coherent light, and the pattern generator may reflect and scatter the coherent light, and the coherent light may be decomposed into a plurality of plane waves having different directions and different phases. Therefore, the light incident on the sample includes a plurality of plane waves, and may be light where a speckle pattern occurs.

[0066] When updating the position information, the controller of the semiconductor measurement device may adjust the first optical model and the second optical model (S110). The first optical model may be an optical model representing the optical characteristics of the light reflected from the pattern generator, and the second optical model may be an optical model representing the optical characteristics of the unit area selected in operation S100 to update the position information. When there are no previously applied first optical models and second optical models (i.e., when the operation of the semiconductor measurement device starts), the controller may generate the first optical model and the second optical model as any model.

[0067] The controller may generate a predicted image using the first optical model and the second optical model adjusted in operation S110 (S120). The predicted image may be an image obtained by estimating a diffraction pattern of light reflected from the pattern generator and the sample and then incident on the image sensor. For example, the controller may generate the predicted image by applying a convolution operation to the first optical model and the second optical model adjusted in operation S110.

[0068] When generating the predicted image, the controller may compare the predicted image with the original image received from the image sensor (S130). Based on the position information updated in operation S100, the original image compared with the predicted image may be an image generated by the image sensor when light is irradiated to a unit area selected from a plurality of unit areas included in the sample.

[0069] The controller may compare the predicted image with the original image and determine whether the difference between the predicted image and the original image is minimized (S140). In an example embodiment, the controller may calculate the difference between the predicted image and the original image using a cost function, for example, the cost function may be defined as shown in the following equation 2.

[0070] <Equation 2>

[0071]

[0072] In the above equation 2, I is the original image, and Ψ is a function representing the optical properties of the light reflected from the pattern generator and may correspond to the first optical model. On the other hand, O may correspond to the second optical model as a function of the optical properties of a unit area actually irradiated and reflected by light among a plurality of unit areas included in the sample. The controller may adjust the first optical model and the second optical model until the difference between the predicted image as a result of the convolution operation of the first optical model and the second optical model and the original image is minimized (S110), may generate a predicted image (S120), and may repeatedly perform an operation of comparing the predicted image with the original image using the cost function (S130).

[0073] When the difference between the predicted image and the original image has not been minimized, operations S110 to S130 may be repeated. When the difference between the predicted image and the original image is minimized, the controller may determine whether the operation has been completed for all of the plurality of unit areas into which the measurement area to be inspected in the sample is divided (S150). When it is determined in operation S150 that there is a unit area that has not been calculated, the position information (S100) may be updated to adjust the position of the stage on which the sample is placed, and operations S110 to S140 may be repeated.

[0074] When it is determined in operation S150 that the operations for all unit areas have been completed, the controller may determine whether consistency is recognized (S160). Figure 3 As described, the plurality of unit areas into which the measurement area is divided considering the viewing angle of the image sensor may be defined so that at least some of them overlap with each other. The controller may determine whether the predicted images corresponding to the unit areas having the overlapping areas are consistent with each other. In an example embodiment, the consistency may be defined as fidelity.

[0075] For example, when the first unit area and the second unit area overlap each other, the controller may determine consistency between a first predicted image generated by applying the arithmetic operations of operations S110 to S140 to the first unit area and a second predicted image generated by applying the arithmetic operations of operations S110 to S140 to the second unit area. Since the first unit area and the second unit area have an overlapping area, the first predicted image and the second predicted image may represent the same image in at least some areas.

[0076] When the consistency between the predicted images is not identified in operation S160, the controller may determine that the optimization of the first optical model and the second optical model is not completed, and may repeat the arithmetic operations of operations S100 to S150. On the other hand, when the consistency between the predicted images is identified in operation S160, it may be determined that the optimization of the first optical model and the second optical model has been completed.

[0077] The controller may use the optimized second optical model to generate a result image (S170). The optimized second optical model may be generated for each of the plurality of unit areas into which the measurement area is divided, and the controller may use the optimized second optical model to restore an image of each of the plurality of unit areas, and merge the images to generate a result image of the measurement area.

[0078] Therefore, the pattern included in the measurement region of the sample may be displayed on the result image. The controller may measure the shape and critical dimension of the pattern included in the measurement region using the result image.

[0079] Fig. 9 is a diagram illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0080] Reference Fig. 9 , the controller of the semiconductor measurement apparatus 500 performs a first operation 501 for updating position information, a second operation 503 for generating a predicted image 530 using the optical models 510 and 520, and a third operation 505 for comparing the predicted image 530 with the original image 540. When the operation of the semiconductor measurement apparatus 500 starts, the controller updates the position information by performing the first operation 501.

[0081] Based on the updated position information, the controller may move the stage on which the sample is placed, thereby irradiating light to one of the plurality of unit areas included in the measurement area. For the convenience of the following explanation, it is assumed that light is irradiated to the first unit area, and therefore, the image sensor may generate an original image 540 of the first unit area.

[0082] The controller may select one from a plurality of optical models for a plurality of unit areas based on the position information updated in the first operation 501. Fig. 9 , the controller for the plurality of unit areas may include a plurality of second optical models 520 to 523. Since the image sensor generates an original image 540 of the first unit area by selecting the first unit area in the first operation 501, the controller may select the second optical model 520 corresponding to the first unit area.

[0083] The controller may generate a predicted image 530 for predicting a diffraction pattern of light reflected from the first unit area by performing a predetermined operation using the first optical model 510 and the second optical model 520. The predicted image 530 may be an image for estimating a diffraction pattern of light emitted from a light source and reflected and / or transmitted from a pattern generator and a sample and then incident on an image sensor. The controller may perform a third operation 505 for comparing the predicted image 530 with an original image 540, and, for example, in the third operation 505, the predicted image 530 and the original image 540 may be compared using a cost function.

[0084] The controller may adjust the first optical model 510 and the second optical model 520 until the value of the cost function applied to the third operation 505 is minimized. In an exemplary embodiment of the present disclosure, the controller may generate a predicted image 530 by performing a forward propagation operation using the first optical model 510 and the second optical model 520. As described above, in the first forward propagation operation, the first optical model 510 and the second optical model 520 may be arbitrarily set, and for example, in the first optical model 510, the amplitude modulation and the phase aberration at each of a plurality of positions defined in the wavefront may be set to any value.

[0085] The predicted image 530 initially generated by the forward propagation operation may have a large difference from the original image 540 actually generated by the image sensor. In an example embodiment of the present disclosure, a back propagation operation may be performed using the difference between the original image and the predicted image. At least one of the first optical model 510 and the second optical model 520 may be adjusted by the back propagation operation.

[0086] When the backpropagation operation is completed, a new predicted image 530 may be generated by performing the forward propagation operation again using the adjusted optical models 510 and 520. The new predicted image 530 may be compared with the original image 540 again, and the difference-based backward propagation operation may be performed again. In this manner, the forward propagation operation and the backward propagation operation may be repeatedly performed. In an example embodiment, the forward propagation operation and the backward propagation operation may be repeated until the value of the cost function calculated from the predicted image 530 generated by the forward propagation operation and the original image 540 generated by the image sensor is minimized.

[0087] When the cost function has a minimum value and the predicted image 530 and the original image 540 match each other, the result image can be generated using the first optical model 510 and the second optical model 520 applied to the forward propagation operation that has generated the predicted image 530. For example, a wavefront image representing the optical characteristics of light incident on the sample can be generated using the first optical model 510. At the same time, the controller can use the second optical model 520 to generate an image representing a pattern included in a unit area where light is reflected from the sample.

[0088] When the predicted image 530 and the original image 540 match each other, the controller may re-operate the first operation 501 to update the position information, and thus may move the stage on which the sample is placed, thereby controlling the light irradiation to other unit areas of the sample. For example, when the stage moves to allow light to be incident on a second unit area different from the first unit area, the image sensor may generate an original image 540 representing a diffraction pattern of light reflected from the second unit area.

[0089] The controller may select a second optical model 521 corresponding to the second unit area from the plurality of second optical models 520 to 523, and may generate a predicted image 530 for the second unit area using the second optical model 521 and the first optical model 510. For the second unit area, the controller may adjust the first optical model 510 and the second optical model 520 by repeating the back propagation operation and the forward propagation operation as described above until the predicted image 530 and the original image 540 match each other.

[0090] When the aforementioned operations are completed for all unit areas, the controller may obtain result images representing the unit areas using the optimized second optical models 520 to 523 , and may combine the images to generate one result image representing the measurement area.

[0091] Fig.10 and Fig.11 is a diagram illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0092] Fig.10 and Fig.11 Each of them can represent a fidelity curve according to the number of iterations of the arithmetic operation and according to the reference Fig. 9 The number of iterations of the forward propagation operation and the backpropagation operation described above generates a result image from each of the first optical model and the second optical model. Fig.10 and Fig.11 In the described example implementation, the fidelity may be defined as in Equation 3 below, and the forward propagation operation and the backward propagation operation may be repeatedly performed until the fidelity is equal to or less than a predetermined threshold.

[0093] <Equation 3>

[0094]

[0095] Fig.10 Result images 600 and 610 and a fidelity curve graph 620 are shown in a state where the forward propagation operation and the backward propagation operation are performed only once. For example, the first result image 600 is a wavefront image of light reflected from the pattern generator after being output from the light source, and the second result image 610 is an image representing some areas of the sample on which the light reflected from the pattern generator is incident. The first result image 600 is generated from a first optical model adjusted by performing the forward propagation operation and the backward propagation operation, and the second result image 610 is generated from a second optical model.

[0096] Since the forward propagation operation and the back propagation operation are not sufficiently repeated, the fidelity may have a very high value as shown in the fidelity graph 620. In addition, a pattern formed in the sample may not be clearly displayed in the second result image 610.

[0097] Fig.11 Result images 600A and 610A and a fidelity graph 620A are shown in a state where the forward propagation operation and the backward propagation operation are repeatedly performed a sufficient number of times. By repeatedly performing the forward propagation operation and the backward propagation operation, as shown in the fidelity graph 620A, the fidelity is reduced by a threshold value or less. In addition, the first optical model and the second optical model are adjusted while repeating the forward propagation operation and the backward propagation operation, and therefore, the first result image 600A and the second result image 610A look the same. Fig.10 are different from those shown in .

[0098] like Fig.11 As shown in , in the first result image 600A generated using the first optical model, the speckle pattern included in the light reflected from the pattern generator can be displayed. At the same time, in the second result image 610A generated using the second optical model, the pattern formed on the sample can be displayed. In this way, by using the semiconductor measurement device according to the example embodiment of the present disclosure, a result image representing the actual shape of the pattern formed on the sample can be obtained, and based on the obtained result image, the shape and critical dimension of the pattern can be accurately measured.

[0099] Fig.12 and Fig.13 is a diagram illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0100] Fig.12 and Fig.13The image shown on the left side of each of may be an image of the sample restored in the first measurement method of irradiating the sample with coherent light output from the light source without the pattern generator. Fig.12 and Fig.13 The image shown on the right side of each of may be an image of the sample restored in the second measurement method of reflecting or transmitting coherent light to the pattern generator and irradiating the sample with coherent light. The semiconductor measurement apparatus according to some embodiments of the present disclosure may use the second measurement method.

[0101] First, refer to Fig.12 , the first image 700 generated by the first measurement method has a relatively narrower viewing angle than the second image 710 generated by the second measurement method. Therefore, in the example embodiment of the present disclosure using the second measurement method instead of the first measurement method, an image of the measurement area of ​​the same area is obtained by capturing fewer images.

[0102] Next, Fig.13 is an enlarged view of an area disposed close to a central portion of each of the first image 700 and the second image 710. Fig.13 , the fourth image 730 that enlarges the area in the second image 710 has a higher resolution than the third image 720 that enlarges the area in the first image 700. Therefore, in the example embodiment of the present disclosure using the second measurement method instead of the first measurement method, the shape and critical dimension of the pattern formed in the sample are more accurately inspected by obtaining a result image with a relatively high resolution.

[0103] Figures 14 to 16 is a diagram illustrating the operation of a semiconductor measuring apparatus according to an example embodiment of the present disclosure.

[0104] Fig.14 and Fig.15 8 is a diagram showing phase images 800 and 810 generated in a semiconductor measurement device according to an example embodiment of the present disclosure. For example, the first optical model and the second optical model are optimized by repeatedly performing a forward propagation operation and a backward propagation operation, and at least one of the optimized first optical model and the optimized second optical model is used to generate a phase image representing a phase difference of light reflected from a sample.

[0105] Reference Fig.14 and Fig.15, the phase difference in the area where light is reflected from the sample is displayed on the phase images 800 and 810. Referring to the first phase image 800 and the second phase image 810, the phase difference changes according to the height of the pattern formed in the sample and the physical properties of the material constituting the pattern formed in the sample. For example, since the refractive index changes according to the type of material constituting the pattern formed in the sample, the phase difference is generated. Therefore, using the first phase image 800 and the second phase image 810, the height of the pattern formed in the sample and the physical properties of the material included in the sample can be known.

[0106] Fig.16 is a diagram showing the result of measuring the depth of a groove present in a sample using a semiconductor measurement device according to an example embodiment of the present disclosure. Fig.16 , a groove is formed by generating scratches in a partial region by applying a polishing process to the sample 900. In order to measure the depth of the groove formed in the sample 900, the semiconductor measurement apparatus according to the example embodiment of the present disclosure irradiates light including a speckle pattern in a partial region of the sample 900, and uses an image sensor to generate a raw image corresponding to the light reflected from the sample 900.

[0107] As described above, the semiconductor measurement apparatus may generate a first optical model and a second optical model, the first optical model representing the optical characteristics of light including the speckle pattern, and the second optical model representing the optical characteristics of the sample 900. The semiconductor measurement apparatus may generate a predicted image using the first optical model and the second optical model, and may optimize the first optical model and the second optical model by repeatedly performing a forward propagation operation and a backward propagation operation, thereby restoring the predicted image. Fig.16 The resulting image 910 is shown in .

[0108] Next, the controller of the semiconductor measurement device can separately obtain a phase image 920 of a partial area selected from the result image 910. Fig.14 and Fig.15 As described, the value of each pixel in the phase image 920 can be determined by the height of the patterns and structures included in the sample 900, and in Fig.16 In the example embodiment shown in FIG. 9 , the value of each pixel included in the phase image 920 may vary according to the depth of the grooves generated during the polishing process.

[0109] Therefore, in an example embodiment of the present disclosure, first to third graphs 930 to 950 respectively indicating the depths of grooves present in first to third positions 921 to 923 specified in the phase image 920 may be obtained. The first to third graphs 930 to 950 may respectively display first measurement lines 931, 941, and 951 indicating the depths of the grooves determined according to the first measurement method, second measurement lines 932, 942, and 952 indicating the depths of the grooves determined according to the second measurement method, and reference lines 933, 943, and 953 indicating the depths of the grooves actually measured. The first measurement method may be a measurement method of directly irradiating coherent light to the sample, and the second measurement method may be a measurement method of irradiating light including a speckle pattern to the sample.

[0110] For example, referring to the first graph 930, the second measurement line 932 may be displayed as being more similar to the reference line 933 than the first measurement line 931. In this manner, in the example embodiment of the present disclosure, light including a speckle pattern may be irradiated to the sample, thereby accurately determining the depth of the grooves included in the sample 900, the height of the pattern, and the material constituting the pattern.

[0111] Fig.17 and Fig.18 is a diagram simply illustrating a semiconductor device to which an inspection operation using a semiconductor measurement apparatus may be applied according to an example embodiment of the present disclosure.

[0112] First, refer to Fig.17 , an inspection operation using a semiconductor measurement device according to an example embodiment of the present disclosure is applied to a semiconductor device 1000, and the semiconductor device 1000 is a vertical memory device. The semiconductor device 1000 includes a plurality of gate electrode layers 1010 and a plurality of insulating layers 1020 stacked in a first direction (Z-axis direction) perpendicular to an upper surface of a substrate 1001, and a channel structure 1030 extending in the first direction and penetrating the gate electrode layers 1010 and the insulating layers 1020. An interlayer insulating layer 1050 is disposed on the plurality of gate electrode layers 1010, and the plurality of gate electrode layers 1010 are divided into a plurality of regions by separation layers 1060 and 1070. At the same time, some of the plurality of gate electrode layers 1010 are divided by an upper separation layer 1080.

[0113] Each of the channel structures 1030 may include a channel layer 1032 connected to the substrate 1001, a gate dielectric layer 1031 disposed between the channel layer 1032 and the gate electrode layer 1010, a buried insulating layer 1033 within the channel layer 1032, and a drain region 1034 on an upper portion of the channel layer 1032. The drain region 1034 may be connected to at least one of the bit lines through a bit line contact, and the bit line may be connected to a page buffer formed in a peripheral circuit region.

[0114] In the process of manufacturing the semiconductor device 1000, a stack structure corresponding to the plurality of gate electrode layers 1010 and the plurality of insulating layers 1020 may be first formed, and a channel structure 1030 extending to the substrate 1001 by penetrating the stack structure may be formed. Therefore, it is necessary to accurately control the depth of the plurality of holes formed in the stack structure in the process of forming the channel structure 1030. In addition, it is necessary to accurately control the depth of the separation layers 1060 and 1070 for dividing the plurality of gate electrode layers 1010 and the plurality of insulating layers 1020 in the process of forming the separation layers 1060 and 1070.

[0115] In order to control such a process, a semiconductor measurement device according to an example embodiment of the present disclosure may be used. As described above, in the semiconductor measurement device according to an example embodiment of the present disclosure, by irradiating the sample with light including a speckle pattern, a pattern formed in the sample may be restored as a result image having high resolution. In addition, by generating a phase image separately from the result image, the height or depth of the pattern included in the sample may be accurately measured. The semiconductor measurement device according to an example embodiment of the present disclosure may be used to measure the depth of a groove formed by an etching process for forming the channel structure 1030 or the separation layers 1060 and 1070, thereby improving the yield of the manufacturing process of the semiconductor device 1000.

[0116] Next, refer to Fig.18 , an inspection operation using a semiconductor measurement apparatus according to an example embodiment of the present disclosure is applied to a semiconductor device 1100, and the semiconductor device 1100 is a dynamic random access memory (DRAM) device. Fig.18 , the semiconductor device 1100 includes a substrate 1101 including a semiconductor material, a gate structure 1110, a bit line structure 1120, an interlayer insulating layer 1130, and a cell capacitor 1140. In the substrate 1101, a separation region 1102 for defining an active region is formed of an insulating material, and the gate structure 1110 is formed in the separation region 1102 embedded in the substrate 1101.

[0117] The gate structure 1110 may include a gate electrode layer 1111, a capping layer 1112, and a gate insulating layer 1113. According to some embodiments, the gate electrode layer 1111 may have a multilayer structure formed of a plurality of different conductive materials such as a metal material, or a word line may be provided. The capping layer 1112 may be formed of polysilicon, silicon nitride, silicon oxide, silicon oxynitride, silicon carbonitride, or silicon carbonitride oxide. The gate insulating layer 1113 may be formed of a high dielectric constant material having a dielectric constant higher than that of silicon oxide and silicon nitride. The channel region may be formed in a region of the substrate 1101 adjacent to the gate electrode layer 1111.

[0118] The interlayer insulating layer 1130 may be disposed on an upper portion of the substrate 1101. The interlayer insulating layer 1130 may include a lower interlayer insulating layer 1131 and an upper interlayer insulating layer 1132. An active region adjacent to the gate structure 1110 may be connected to a buried contact BC penetrating the lower interlayer insulating layer 1131, and the buried contact BC may be connected to a landing pad LP penetrating the upper interlayer insulating layer 1132. The buried contact BC connected to the active region between the gate structures 1110 adjacent to each other may be connected to a bit line structure 1120. The bit line structure 1120 may include a conductive layer 1121, a capping layer 1122, and a spacer 1123.

[0119] The unit capacitor 1140 extending in the first direction (Z-axis direction) may be connected to the upper portion of the landing pad LP. The unit capacitor 1140 may include a lower electrode 1141, a capacitor dielectric layer 1142, and an upper electrode 1143, and the shape of the lower electrode 1141 may have a shape other than Fig.18 The lower electrode 1141 may be formed of a metal and a metal compound, and the upper electrode 1143 may be formed of a doped semiconductor material such as silicon germanium (SiGe).

[0120] In the process of manufacturing the semiconductor device 1100, for example, the buried contact BC may be formed by forming a groove through an etching process that removes a partial region of the first interlayer insulating layer 1131 and filling the groove with a conductive material. As the integration of the semiconductor device 1100 increases and the gap between the gate structures 1110 decreases, the position of the buried contact BC needs to be accurately specified, and the width or depth of the groove forming the buried contact BC needs to be accurately controlled to prevent defects.

[0121] In order to control such an etching process, a semiconductor measurement device according to an example embodiment of the present disclosure may be used. As described above, in the semiconductor measurement device according to an example embodiment of the present disclosure, a high-resolution result image may be generated using light including a speckle pattern, and a phase image may be used to accurately measure the depth and width of a pattern included in a sample. The semiconductor measurement device according to an example embodiment of the present disclosure may be used to measure the position, width, and depth of a groove for forming a buried contact BC, thereby improving the yield of the manufacturing process of the semiconductor device 1100.

[0122] Although this specification contains many specific implementation details, these should not be interpreted as limitations on the scope that can be claimed, but rather as descriptions of features that can be dedicated to a particular implementation of a particular invention. Certain features described in the context of a separate implementation in this specification may also be implemented in combination in a single implementation. On the contrary, the various features described in the context of a single implementation may also be implemented in multiple implementations individually or in any suitable sub-combination. In addition, although features may be described above as working in certain combinations and even initially claimed as such, one or more features from the claimed combination may be removed from the combination in some cases, and the claimed combination may be directed to a sub-combination or a variation of the sub-combination.

[0123] The present disclosure is not limited to the above-mentioned embodiments and drawings, but is limited by the appended claims. Therefore, those skilled in the art may make various substitutions, modifications or changes without departing from the scope of the present disclosure defined by the appended claims, and these substitutions, modifications or changes should be interpreted as being included within the scope of the present disclosure.

Claims

1. A semiconductor measuring device, include: a light source configured to output light in a predetermined wavelength band; a pattern generator configured to scatter light output from the light source to produce a speckle light pattern; a stage arranged to receive the speckle light pattern from the pattern generator, wherein the stage is configured to support a sample in a position to reflect the speckle light pattern; an image sensor positioned to receive the speckle light pattern reflected from the sample and to generate a raw image representing a diffraction pattern of the speckle light pattern reflected from the sample; and A controller configured to: generating a predicted image of light incident on the image sensor using a first optical model representing optical properties of the speckle light pattern and a second optical model representing optical properties of a measurement area of ​​the sample reflecting the speckle light pattern, comparing the predicted image to the original image, and A result image representing the measurement area is generated.

2. The semiconductor measuring device according to claim 1, further comprising: include: A mirror is configured to reflect the speckle light pattern from the sample to the image sensor.

3. The semiconductor measuring device according to claim 1, in, The wavelength band includes at least one of an ultraviolet wavelength band, an extreme ultraviolet wavelength band, and a visible wavelength band.

4. The semiconductor measuring device according to claim 1, in, The speckle light pattern includes a plurality of plane waves oriented in different directions.

5. The semiconductor measuring device according to claim 1, in, The controller is configured to optimize each of the first optical model and the second optical model by performing a back-propagation operation using a difference between the predicted image and the original image.

6. The semiconductor measuring device according to claim 1, in, The controller is configured to optimize each of the first optical model and the second optical model to minimize a difference between the predicted image and the original image, and The result image is generated using the optimized first optical model and the optimized second optical model.

7. The semiconductor measuring device according to claim 6, in, The controller is configured to: obtaining a phase image of light incident on the image sensor using the optimized first optical model, the optimized second optical model, or both the optimized first optical model and the optimized second optical model, and The phase image is used to determine a physical property of a layer included in a measurement region of the sample, a height of a pattern formed in the measurement region of the sample, or both the physical property and the height of the pattern.

8. The semiconductor measuring device according to claim 1, in, The result image is an image representing the shape of a pattern formed in the measurement region of the sample.

9. The semiconductor measuring device according to claim 1, in, The controller is configured to move the stage so that the speckle light pattern is reflected from a plurality of unit areas in a measurement area of ​​the sample, and The image sensor is configured to generate a plurality of original images corresponding to the plurality of unit areas, and the controller is configured to generate a plurality of predicted images of light reflected from the plurality of unit areas and incident on the image sensor.

10. The semiconductor measuring device according to claim 9, in, At least two unit areas among the plurality of unit areas overlap.

11. The semiconductor measuring device according to claim 10, in, The controller is configured to: optimizing the first optical model and the second optical model so that differences between the plurality of predicted images and the plurality of original images are minimized and consistency between the plurality of predicted images is identified, and A plurality of result images of the plurality of unit areas are generated using the optimized first optical model and the optimized second optical model.

12. The semiconductor measuring device according to claim 9, in, The controller is configured to apply different second optical models to at least two unit areas among the plurality of unit areas.

13. The semiconductor measuring device according to claim 1, further comprising: include: a housing having a space in which the light source, the pattern generator, the stage, and the image sensor are disposed; as well as A pump is configured to maintain the space in a vacuum state.

14. A semiconductor measuring device, include: a light source configured to output coherent light; a pattern generator configured to emit light including a plurality of plane waves oriented in different directions to a sample by scattering the coherent light; a stage configured to adjust the position of the sample so that light is reflected in a selected area, wherein the selected area is a partial area of ​​the sample; as well as An image sensor is configured to generate a raw image in response to light reflected from the selected area.

15. The semiconductor measuring device according to claim 14, in, The pattern generator includes at least one of a diffractive optical element, an optical lattice structure, a scattering element, and a wavefront modulator.

16. The semiconductor measuring device according to claim 14, in, The original image is an image representing a diffraction pattern of light.

17. The semiconductor measuring device according to claim 16, further comprising: include: A controller configured to: generating a predicted image for estimating diffraction characteristics of light incident on the image sensor using a first optical model representing optical characteristics of light emitted by the pattern generator and a second optical model representing optical characteristics of the selected area, using a difference between the predicted image and the original image to optimize the first optical model and the second optical model, and A result image representing the shape of the structure included in the selected area is generated using the first optical model, the second optical model, or both the first optical model and the second optical model.

18. The semiconductor measuring device according to claim 17, in, The controller is configured to determine an initial value of each of the first optical model and the second optical model.

19. A semiconductor measuring device, include: speckle illumination configured to output light comprising a plurality of plane waves oriented in different directions; a stage in which a sample for reflecting light output from the speckle illumination is disposed; an image sensor configured to generate a raw image in response to light reflected from a partial area of ​​the sample; as well as A controller configured to: generating a predicted image for estimating a diffraction pattern of light incident on the image sensor by performing a forward propagation operation using a first optical model and a second optical model, the first optical model representing optical characteristics of light output by the speckle illumination, the second optical model represents the optical properties of light reflected from the sample, performing a back-propagation operation for adjusting the first optical model and the second optical model based on a difference between the predicted image and the original image, and A result image representing a partial area of ​​the sample is obtained by repeatedly performing the forward propagation operation and the backward propagation operation.

20. The semiconductor measuring device according to claim 19, in, The controller is configured to: determining the fidelity of the predicted image by applying the predicted image and the original image to a cost function, and The forward propagation operation and the backward propagation operation are repeatedly performed until the fidelity is equal to or less than a predetermined threshold.

Images