The present disclosure relates to a profile detection method and an information processing apparatus.
JP2014-139537A discloses a technique of imaging, by a scanning electron microscope (SEM), a circuit pattern present at a desired position on a semiconductor device in order to measure or inspect a semiconductor.
Patent Document 1: JP2014-139537A
A profile detection method according to an aspect of the present disclosure includes a region detection step, a boundary detection step, and a contour detection step. In the region detection step, data of an image in which a plurality of recesses recessed in one direction are arranged in an intersecting direction with respect to the one direction is analyzed to detect each recess region in the image. In the boundary detection step, the data is analyzed to detect a boundary of a film included in the image. In the contour detection step, the data is analyzed to detect a contour of the recess for the each recess region in the image.
Hereinafter, embodiments of a profile detection method, a profile detection program, and an information processing apparatus disclosed in the present application will be described in detail with reference to the drawings. The disclosed profile detection method, profile detection program, and information processing apparatus are not limited by the present embodiment.
In the related art, a process engineer supports optimization of a recipe in a semiconductor manufacturing process. For example, whether the recipe is appropriate is determined by imaging, by a scanning electron microscope, a cross section of a semiconductor device in which a recess such as a trench or a hole is formed, and measuring a dimension such as a critical dimension (CD) of the recess in the captured image. The process engineer manually specifies a range of the recess in the captured image and manually specifies a position of a contour in which the dimension is to be measured, and a dimension measurement operation is person-dependent. As a result, it takes time to perform dimension measurement. In addition, since the measurement operation such as specifying of the position of the contour in which the dimension is to be measured is person-dependent, a person-dependent error may occur in the measured dimension. In addition, when it is attempted to measure dimensions of a large number of recesses, it takes time and effort.
Therefore, a technique for improving efficiency of the dimension measurement is expected.
Embodiments will be described. Hereinafter, a case in which a dimension of a recess in a captured image is measured by an information processing apparatus 10 will be described as an example.
The information processing apparatus 10 includes a communication I/F (interface) unit 20, a display 21, an input unit 22, a storage 23, and a controller 24. The information processing apparatus 10 may include another device included in a computer in addition to the above devices.
The communication I/F unit 20 is an interface that performs communication control with other apparatuses. The communication I/F unit 20 is connected to a network (not shown), and transmits and receives various kinds of information to and from other apparatuses via the network. For example, the communication I/F unit 20 receives data of a digital image captured by a scanning electron microscope.
The display 21 is a display device that displays various kinds of information. Examples of the display 21 include display devices such as a liquid crystal display (LCD) and a cathode ray tube (CRT). The display 21 displays various kinds of information.
The input unit 22 is an input device that inputs various kinds of information. Examples of the input unit 22 include input devices such as a mouse and a keyboard. The input unit 22 receives an operation input from a user, such as a process engineer, and inputs operation information indicating the received operation content to the controller 24.
The storage 23 is a storage device such as a hard disk, a solid state drive (SSD), or an optical disk. The storage 23 may be a semiconductor memory capable of rewriting data, such as a random access memory (RAM), a flash memory, and a non volatile static random access memory (NVSRAM).
The storage 23 stores an operating system (OS) or various programs including a profile detection program to be executed by the controller 24, which will be described later. Further, the storage 23 stores various types of data used in the program executed by the controller 24. For example, the storage 23 stores image data 23a.
The image data 23a is data of an image obtained by imaging a cross section of a semiconductor device by the scanning electron microscope. The semiconductor device is formed on, for example, a substrate such as a semiconductor wafer. The image data 23a is acquired by imaging, by the scanning electron microscope, a cross section of the substrate on which the semiconductor device is formed.
The controller 24 is a device that controls the information processing apparatus 10. As the controller 24, an electronic circuit such as a central processing unit (CPU), a micro processing unit (MPU) and a graphics processing unit (GPU), or an integrated circuit such as an application specific integrated circuit (ASIC) and a field programmable gate array (FPGA) can be adopted. The controller 24 has an internal memory for storing programs defining various process procedures or control data, and executes various processes by the programs and the control data.
The controller 24 functions as various processors by the various programs operating. For example, the controller 24 includes an operation receiver 24a, a region detector 24b, a boundary detector 24c, a contour detector 24d, and a measurement unit 24e.
The operation receiver 24a receives various operations. For example, the operation receiver 24a displays an operation screen on the display 21, and receives, from the input unit 22, various operations on the operation screen. For example, the operation receiver 24a receives, from the operation screen, specifying of the image data 23a to be a profile detection target. The operation receiver 24a reads the specified image data 23a from the storage 23, and causes the display 21 to display an image of the read image data 23a. The operation receiver 24a receives, from the operation screen, an instruction for starting profile detection.
For example, when determining whether the recipe is appropriate, the process engineer specifies, from the operation screen, the image data 23a of a cross section of a semiconductor device which has been subjected to substrate processing in a recipe whose appropriacy is to be determined. Then, the process engineer instructs the start of the profile detection from the operation screen.
When instructed to start the profile detection, the region detector 24b analyzes the specified image data 23a to detect a region in each recess 50 in the image.
For example, the region detector 24b performs a frequency analysis on the image in the x direction to specify a range of the image including the recesses 50 with respect to the y direction. For example, the region detector 24b performs the frequency analysis on the image in the x direction at each position in the y direction in the image, and specifies a range in which frequencies corresponding to the recesses 50 are obtained as the range of the image including the recesses 50 with respect to the y direction.
The region detector 24b detects a maximum value of the integrated value profile IS. The region detector 24b specifies a range of a skirt of a peak including the detected maximum value as the range of the image including the recesses 50 with respect to the y direction. For example, the region detector 24b obtains a baseline of the integrated value profile IS, and specifies a range in which the peak is the baseline as the range of the image including the recesses 50 with respect to the y direction. Alternatively, the region detector 24b specifies a range in which a change in the integrated values from the peak including the maximum value is equal to or greater than a predetermined value as the range of the image including the recesses 50 with respect to the y direction. In
The region detector 24b detects the region in the recess 50 from the specified range of the image. For example, the region detector 24b calculates, from the specified range of the image, an average value of luminances of pixels in the y direction for each position in the x direction in the image. The region detector 24b detects the region in the recess 50 from the specified range of the image based on the calculated average value at each position in the x direction.
The region detector 24b binarizes values in the average value profile AP in the x direction. For example, the region detector 24b obtains an average value of the average value profile in the x direction, and binarizes the values in the average value profile using the obtained average value as a threshold value. For example, the region detector 24b sets, as a first value, a value in the average value profile which is equal to or greater than the threshold value, sets, as a second value, a value in the average value profile which is smaller than the threshold value, and binarizes the values in the average value profile.
The boundary detector 24c analyzes the specified image data 23a to detect a boundary of a film included in the image.
For example, for the region in the recess 50 detected by the region detector 24b, the boundary detector 24c detects the boundary of the film based on a change in luminance of a side wall constituting the recess 50 in the y direction. For example, the boundary detector 24c obtains, for the region in the recess 50 detected by the region detector 24b, the change in luminance of the side wall constituting the recess 50 in the y direction. The boundary detector 24c detects a portion in which the change in luminance is large as the boundary of the film.
The contour detector 24d analyzes the specified image data 23a to detect a contour of the recess 50 for the region in the recess 50 in the image. For example, the contour detector 24d detects, for the region in the recess 50 detected by the region detector 24b, the contour of the recess 50 based on a change in luminance in the x direction.
Since the information processing apparatus 10 according to the embodiment can automatically detect the range of the recess 50 or the contour of the recess 50 in the image in this manner, the efficiency of the dimension measurement can be improved.
The measurement unit 24e measures the dimension. For example, the operation receiver 24a causes the display 21 to display the image in which the contour of the recess 50 is detected by the contour detector 24d, and receives, from the input unit 22, specifying of a position of the contour of the recess 50 at which the dimension is to be measured. The measurement unit 24e measures a CD of the recess 50 at the specified position of the contour.
The measurement unit 24e may measure the dimension of the recess 50 such as a CD at a predetermined position of the contour without receiving the specifying of the position. The position at which the dimension is to be measured may be set in advance or may be set based on detection results of the boundary detector 24c or the contour detector 24d. For example, the measurement unit 24e may measure, at a position of a height of the boundary of the film detected by the boundary detector 24c, the dimension such as a CD at the boundary of the film from the contour of each recess 50 detected by the contour detector 24d. The measurement unit 24e may measure the dimension such as a CD at each position in the y direction from the edge profile of the contour of each recess 50 detected by the contour detector 24d.
The measurement unit 24e may cause the display 21 to display the measured dimension together with the measurement position, may store, in the storage 23, data of the measured dimension together with the measurement position, or may transmit the data to another apparatus via the communication I/F unit 20.
Since the information processing apparatus 10 according to the embodiment can measure the dimension of the recess 50 in the image in this manner, the efficiency of the dimension measurement can be improved. As a result, the time taken to measure the dimensions can be shortened. Since the information processing apparatus 10 can detect the contour that is the position at which the dimension is to be measured, it is possible to reduce the person-dependent error that occurs in the measured dimension. The information processing apparatus 10 can efficiently measure the dimensions of a large number of recesses 50. For example, by automatically measuring the dimension of each recess 50 included in the image, a large number of length measurement values used for data analysis can be collected. An abnormal recess 50 can be detected by automatically measuring the dimension of each recess 50 included in the image and analyzing the measured dimension of each recess 50.
Next, a flow of a profile detection method according to the embodiment will be described. The information processing apparatus 10 according to the embodiment performs the profile detection method by executing the profile detection program.
The operation receiver 24a receives, from the operation screen, specifying of the image data 23a as a profile detection target (step S10). The operation receiver 24a receives, from the operation screen, the instruction for starting the profile detection (step S11).
The region detector 24b analyzes the specified image data 23a to detect the region in the recess 50 in the image (step S12). For example, the region detector 24b performs a frequency analysis on the image in the x direction to specify a range of the image including the recesses 50 with respect to the y direction. Then, the region detector 24b detects the region in the recess 50 from the specified range of the image.
The boundary detector 24c analyzes the specified image data 23a to detect the boundary of the film included in the image (step S13). For example, for the region in the recess 50 detected by the region detector 24b, the boundary detector 24c detects the boundary of the film based on a change in luminance of a side wall constituting the recess 50 in the y direction.
The contour detector 24d analyzes the specified image data 23a to detect the contour of the recess 50 for the region in the recess 50 in the image (step S14). For example, the contour detector 24d detects, for the region in the recess 50 detected by the region detector 24b, the contour of the recess 50 based on a change in luminance in the x direction.
The measurement unit 24e measures the dimension (step S15) and ends the processing. For example, the operation receiver 24a causes the display 21 to display the image in which the contour of the recess 50 is detected by the contour detector 24d, and receives, from the input unit 22, specifying of a position of the contour of the recess 50 at which the dimension is to be measured. The measurement unit 24e measures a CD of the recess 50 at the specified position of the contour.
As described above, the profile detection method according to the embodiment includes a region detection step (step S12), a boundary detection step (step S13), and a contour detection step (step S14). In the region detection step, data (image data 23a) of an image in which the recesses 50 recessed in one direction (y direction) are arranged in an intersecting direction (x direction) with respect to the one direction is analyzed to detect the region in the recess 50 in the image. In the boundary detection step, the data is analyzed to detect a boundary of a film included in the image. In the contour detection step, the data is analyzed to detect a contour of the recess 50 for the region in the recess 50 in the image. Accordingly, the profile detection method according to the embodiment can improve efficiency of dimension measurement. For example, the profile detection method according to the embodiment can shorten the time taken to measure a dimension. Further, the profile detection method according to the embodiment can reduce a person-dependent error that occurs in the measured dimension. In addition, the profile detection method according to the embodiment can efficiently measure dimensions of a large number of recesses 50.
In the region detection step, a frequency analysis is performed on the image in the intersecting direction to specify a range of the image including the recesses 50 with respect to the one direction, and the region in the recess 50 is detected from the specified range of the image. In the region detection step, the frequency analysis on the image is performed in the intersecting direction at each position in the one direction of the image, and a range in which frequencies corresponding to the recesses 50 are obtained is specified as the range of the image including the recesses 50 with respect to the one direction. Accordingly, the profile detection method according to the embodiment can accurately specify the range of the image including the recesses 50 with respect to the one direction, and can detect the region in the recess 50 from the specified range of the image.
In the region detection step, an average value of luminances of pixels in the one direction is calculated from the specified range of the image for each position in the intersecting direction of the image, and the region in the recess 50 is detected from the specified range of the image based on the calculated average value at each position in the intersecting direction. Accordingly, the profile detection method according to the embodiment can accurately detect the region in the recess 50 from the specified range of the image.
In the boundary detection step, for the region in the recess 50 detected in the region detection step, the boundary of the film is detected based on a change in luminance of a side wall constituting the recess 50 in the one direction. In the boundary detection step, the change in luminance of the side wall in the one direction is obtained, and a portion in which the change is large is detected as the boundary of the film. Accordingly, the profile detection method according to the embodiment can accurately detect the boundary of the film.
In the contour detection step, for the region in the recess 50 of the image, the contour of the recess 50 is detected based on a change in luminance in the intersecting direction. In the contour detection step, for the region in the recess 50 of the image, the change in luminance in the intersecting direction is obtained at each position in the one direction, and a portion in which the change is large is detected as the contour of the recess 50. Accordingly, the profile detection method according to the embodiment can accurately detect the contour of the recess 50.
Hitherto, the embodiment has been described above. The embodiment disclosed herein is illustrative and should not be construed as limiting in all aspects. The embodiment described above may be embodied in various forms. The embodiment described above may be omitted, replaced, or modified in various forms without departing from the scope and spirit of the claims.
For example, in the above embodiment, the case in which the region detection (step S12), the boundary detection (step S13), and the contour detection (step S14) are sequentially performed has been described as an example. However, the present disclosure is not limited thereto. The order of the region detection, the boundary detection, and the contour detection may be different. For example, the method may be performed in the order of the contour detection, the region detection, and the boundary detection. For example, the method may be performed in the following order. The contour detector 24d performs a binarization process on an entire image of the specified image data 23a to acquire a binary image, and specifies, from the binary image, an outer contour of the recess that is the boundary. For example, the contour detector 24d specifies, as the contour, a pixel that is a binary boundary of the binary image. Similar to the region detection according to the above embodiment, the region detector 24b analyzes the specified image data 23a to detect the region in the recess 50 of the image. Similar to the region detection according to the above embodiment, the boundary detector 24c analyzes the image data 23a to detect the boundary of the film included in the image.
The region detection, the boundary detection, and the contour detection may be performed in parallel with each other regardless of the order, or may be performed by combining two or more processes. Detection results may be used mutually. For example, when the region detection is performed, the region detection may be performed using the binary image obtained by the contour detection.
In the above embodiment, the case in which the dimensions of the recesses of the semiconductor device formed on the substrate such as a semiconductor wafer are measured has been described as an example. However, the present disclosure is not limited thereto. The substrate may be any substrate such as a glass substrate. The profile detection method according to the embodiment may be applied to dimension measurement for a recess in any substrate. For example, the profile detection method according to the embodiment may be applied to dimension measurement for a recess formed in a substrate for an FPD.
It shall be understood that the embodiments disclosed herein are illustrative and are not restrictive in all aspects. Indeed, the above-described embodiments can be implemented in various forms. The embodiments described above may be omitted, replaced, or modified in various forms without departing from the scope and spirit of the appended claims.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosures. Indeed, the embodiments described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosures. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosures.
According to the present disclosure, it is possible to improve efficiency of dimension measurement.
This application is a bypass continuation application of international application No. PCT/JP2021/042891 having an international filing date of Nov. 24, 2021, and designating the United States, the international application being based upon and claiming the benefit of priority from U.S. Provisional Application No. 63/139,948, filed on Jan. 21, 2021, the entire contents of each are incorporated herein by reference.
Number | Date | Country | |
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63139948 | Jan 2021 | US |
Number | Date | Country | |
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Parent | PCT/JP2021/042891 | Nov 2021 | WO |
Child | 18224077 | US |