Information processing method and information processing device

Abstract

To provide an information processor capable of specifying a position of a specific point with high accuracy.SOLUTION: An information processor is provided, comprising: an acquisition unit that acquires the coordinates of alignment marks of multiple sections of a calibration sample having a region divided by four alignment marks; and a recording unit that calculates, for each section, coefficients for coordinate transformation of the region included in the section into a coordinate system based on the coordinates of the section's alignment marks, and records the coefficients associated with each section. The information processor further comprises a determination unit that determines which section, among multiple sections of the calibration sample, a specific point in the inspection sample belongs to; a reading unit that reads the coefficients associated with the section determined to be applicable; and a conversion unit that converts the coordinates of the specific point based on the coefficients.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an information processing method and an information processing device. [Background technology]

[0002] Patent Document 1 describes a technique for detecting defects present in a sample. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-085839 Summary of the Invention [Problem to be solved by the invention]

[0004] It is necessary to accurately control the position of a specific point on the sample.

[0005] The object of the present disclosure has been made to solve such problems, and is to provide an information processing method and an information processing device that can manage the position of a specific point with high accuracy. [Means for solving the problem]

[0006] The information processing method of the present disclosure includes: an acquiring step of acquiring the coordinates of alignment marks of a plurality of sections of a calibration sample having an area defined by four alignment marks; a recording step of calculating, for each of the sections, a coefficient for converting a region included in the section into a coordinate system based on the coordinates of the alignment mark of the section, and recording the coefficient in association with the section; The information processing method includes the steps of:

[0007] The information processing method of the present disclosure includes: determining which of the plurality of compartments in the calibration sample a particular point in the test sample belongs to; a reading step of reading the coefficients associated with the partition determined to belong to the partition; a transformation step of transforming the coordinates of the specific point based on the coefficients; may further comprise:

[0008] The information processing method of the present disclosure includes: Furthermore, in the obtaining step, the coordinates of the alignment marks of the sections may be obtained by correcting them with a function based on elapsed time.

[0009] The information processing method of the present disclosure includes: Furthermore, in the obtaining step, the coordinates of adjacent rows of alignment marks in the section may be measured by scanning in the same direction.

[0010] The information processing method of the present disclosure includes: a second transformation step of further transforming the transformed coordinates obtained in the transformation step based on a global alignment mark of the inspection sample; may also be provided.

[0011] The information processing method of the present disclosure includes: The coordinate transformation may be a Helmert transformation, an affine transformation, or a homography transformation.

[0012] The information processing device of the present disclosure includes: an acquisition unit that acquires coordinates of alignment marks of a plurality of sections of a calibration sample having an area defined by four alignment marks; a recording unit that calculates, for each of the sections, a coefficient for converting a region included in the section into a coordinate system based on the coordinates of the alignment mark of the section, and records the coefficient in association with the section; The information processing device is provided with:

[0013] The information processing device of the present disclosure includes: a determination unit that determines to which of a plurality of sections in the calibration sample a particular point in the test sample belongs; a reading unit that reads out the coefficients associated with the partitions that are determined to belong to the image; a conversion unit that converts the coordinates of the specific point based on the coefficient; may further comprise:

[0014] The information processing device of the present disclosure includes: Furthermore, the acquisition unit may acquire the coordinates of the alignment marks of the sections by correcting them with a function based on elapsed time.

[0015] The information processing device of the present disclosure includes: Furthermore, the acquisition unit may measure the coordinates of adjacent rows of alignment marks in the section by scanning in the same direction.

[0016] The information processing device of the present disclosure includes: a second conversion unit that further converts the converted coordinates obtained by the conversion unit based on a global alignment mark of the test sample; may also be provided.

[0017] In the information processing device of the present disclosure, The coordinate transformation may be a Helmert transformation, an affine transformation, or a homography transformation. [Effects of the Invention]

[0018] The present disclosure can provide an information processing method and an information processing device that can manage the position of a specific point with high accuracy. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a block diagram showing a configuration of an information processing device according to an embodiment; [Figure 2] 1 is a flowchart of an information processing method according to an embodiment. [Figure 3] FIG. 2 is a schematic diagram showing alignment mark coordinates according to the embodiment. [Figure 4] 10A and 10B are schematic diagrams showing deviations of alignment mark coordinates according to an embodiment; [Figure 5] 4 is a schematic diagram showing the position of a specific point relative to alignment mark coordinates according to the first embodiment; FIG. [Figure 6] 3A and 3B are schematic diagrams of alignment mark coordinates and specific points before and after calibration according to the first embodiment, and a schematic diagram of global alignment mark coordinates. [Figure 7] 5A and 5B are schematic diagrams illustrating measurements of alignment mark coordinates over time according to the first embodiment. [Figure 8] 5A and 5B are diagrams illustrating examples of one-way measurement and meandering measurement of alignment mark coordinates according to the first embodiment. [Figure 9] 1 is a block diagram illustrating a physical configuration of an information processing apparatus according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] Embodiment Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the invention according to the claims is not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential means for solving the problems. For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. In each drawing, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary.

[0021] (Description of Information Processing Device and Information Processing Method According to the Embodiment) FIG. 1 is a block diagram showing a configuration of an information processing device according to an embodiment. FIG. 2 is a flowchart of an information processing method according to an embodiment. FIG. 3 is a schematic diagram showing alignment mark coordinates according to an embodiment. FIG. 4 is a schematic diagram showing deviations of alignment mark coordinates according to an embodiment. FIG. 9 is a block diagram showing a physical configuration of an information processing device according to an embodiment. The information processing device and the information processing method according to the embodiment will be described with reference to FIGS. 1 to 4 and 9. The information processing device according to the embodiment is used to identify defects in a mask, for example.

[0022] In EUV lithography, a method is used in which an absorber is placed directly above a transferable phase defect. In this method, the defect coordinates are determined using marks at the four corners of the mask as references, and the phase defect coordinates are then determined, and the phase defect coordinates and the absorber are aligned to the nanometer order.

[0023] For example, there is a need to accurately manage defect positions for the following reasons: It is conceivable that, due to differences between inspection systems, the coordinate positions recorded as the positions where defects were detected may differ slightly, even on the same sample. Or, when a defect is detected by a first system and then repaired or invalidated by a second system, it is conceivable that, due to differences between the systems, the second system may record a position on the sample where the defect was detected by the first system that is slightly different from the position where the defect was detected.

[0024] Therefore, in order to mitigate the influence of differences between inspection devices that detect defects and differences between defect inspection devices and devices in subsequent processes, an apparatus and method for identifying and managing the position of defects are proposed.

[0025] As shown in Figure 3, coordinates called alignment marks are arranged on the mask in a grid pattern, arranged in multiple columns and rows. Here, the alignment marks are cross marks numbered, for example, from 1 to 225. Alignment marks are also called fiducial marks (FMs). As shown in the lower right of Figure 3, even if correction is made using only the FM coordinates at the four outermost corners of the mask, there are still various measurement errors distributed across the mask surface.

[0026] As shown in Figure 4, the in-plane extension direction differs depending on the grid of each alignment mark. For example, the top left grid extends in the upper left direction. As shown in the right image of Figure 4, if we enlarge this top left grid, we can see that a specific feature such as a defect located at the position of a black triangle in the black grid before calibration will be detected at the position of a white triangle when aligned with the white grid after calibration. By performing a conversion based on the four alignment marks in the grid area to which the specific feature belongs, the position of the specific feature can be detected regardless of machine differences.

[0027] As shown in Fig. 1, the information processing device 100 includes an acquisition unit 101 and a recording unit 102. As shown in Fig. 9, the physical configuration of the information processing device 100 includes a memory 902 that stores programs and a processor 901 that executes processing based on the stored programs. The information processing device 100 may be configured as a single device or multiple devices. The information processing device 100 may also be configured as a cloud server that distributes and processes some or all of its functions.

[0028] The acquisition unit 101 acquires the coordinates of the alignment marks of a plurality of sections of a calibration sample having an area divided by four alignment marks. The recording unit 102 calculates a coefficient for converting the area included in each section into a coordinate system based on the coordinates of the alignment marks of the section, and records the coefficient in association with the section. The recording unit 102 calculates and records a coefficient for converting each section into a corrected grid.

[0029] The coordinate transformation may be a Helmert transformation using two grid points, an affine transformation using three grid points, or a homography transformation called a projective transformation using four grid points. Since four grid points are measured, a homography transformation is preferred because it results in less error.

[0030] Homography transformation is as follows: x' is the point after transformation and x is the point before transformation.

number

number

number

[0031] The above configuration provides an information processing device that can manage the position of a specific point with high accuracy.

[0032] 2, the information processing method according to the embodiment first acquires coordinates (step S201). The acquisition unit 101 of the information processing device 100 executes an acquisition step of acquiring the coordinates of alignment marks of a plurality of sections of a calibration sample having an area divided by four alignment marks.

[0033] Next, a coefficient for coordinate conversion is calculated and recorded in association with the partition (step S202). The recording unit 102 of the information processing device 100 executes a recording step of calculating a coefficient for converting the coordinates of the area included in each partition into a coordinate system based on the coordinates of the alignment mark of the partition, and recording the coefficient in association with the partition.

[0034] The above configuration provides an information processing method that can manage the position of a specific point with high accuracy.

[0035] (Description of Information Processing Device and Information Processing Method According to First Embodiment) FIG. 5 is a schematic diagram showing the position of a specific point relative to alignment mark coordinates according to the first embodiment. FIG. 6 is a schematic diagram of alignment mark coordinates and specific points before and after calibration according to the first embodiment, and a schematic diagram of global alignment mark coordinates. FIG. 7 is a schematic diagram of measurements of alignment mark coordinates over time according to the first embodiment. FIG. 8 is a diagram showing examples of unidirectional measurement and meandering measurement of alignment mark coordinates according to the first embodiment. The information processing device and method according to the first embodiment will be described with reference to FIGS. 5 to 8.

[0036] The inspection sample includes a specific point. The specific point may be, for example, a point representing the position of a defect detected on the sample, a point representing the position of a foreign substance attached to the sample, or a point representing the center position within the sample, and may be any point of interest depending on the application of the information processing device or the application of the sample. The specific point may also be read as a specific position. The inspection sample may be a sample different from the calibration sample. In that case, the calibration sample is used for information processing and inspection calibration of the inspection sample. The inspection sample does not need to have a grid-like alignment mark arranged in multiple vertical and horizontal rows.

[0037] As mentioned at the beginning, it is desirable to accurately acquire and manage the position information of a specific point on the test sample, i.e., the coordinates of the specific point (hereinafter sometimes referred to as "specific point coordinate values"). Therefore, as shown in FIG. 5, the acquired specific point coordinate values ​​are determined to belong to which area of ​​the test sample corresponding to the section of the calibration sample. In other words, the area of ​​the test sample corresponding to which area surrounded by four alignment marks on the calibration sample the specific point is included in is determined. This determination may be made based on a comparison of the acquired specific point coordinate values ​​with the coordinates of the alignment marks on the calibration sample. Furthermore, if the test sample has a grid-like alignment mark formed on it, arranged in multiple rows and columns, similar to the calibration sample, this determination may also be made based on the coordinate values ​​of the alignment marks on the test sample. In this manner, the determination step determines which section of the calibration sample the specific point is included in. Then, coefficients for homography transformation of the specific point coordinate values ​​to calibration reference coordinates (coordinates based on the alignment marks of the section) are calculated, and these coefficients are applied to the specific point coordinates to perform coordinate transformation.

[0038] In this way, the coordinates of a specific point can be obtained, identified, or managed with high accuracy by a reading step that reads out the coefficients associated with the partition to which the specific point is determined to belong, and a conversion step that converts the coordinates of the specific point based on the coefficients.

[0039] The information processing device according to the first embodiment includes a determination unit, a readout unit, and a conversion unit. The determination unit determines to which of a plurality of sections in a calibration sample a specific point in a test sample belongs. The readout unit reads out a coefficient associated with the section to which the specific point belongs. The conversion unit converts the coordinates of the specific point based on the coefficient.

[0040] The above configuration provides an information processing device and an information processing method that can identify the position of a specific point with high accuracy.

[0041] As described above, the information processing device according to the first embodiment transforms the coordinates of the specific point based on the coefficients associated with the section of the calibration sample to which the specific point is determined to belong. In the upper diagram of FIG. 6, the position of the specific point before the coordinate transformation is indicated by a black triangle, and the position of the specific point after the coordinate transformation is indicated by a white triangle. The information processing device according to the first embodiment then further transforms the position of the specific point after the coordinate transformation based on a global alignment mark, as shown in the lower diagram of FIG. 6. The global alignment mark is an alignment mark provided on the outermost part of the sample, and represents, for example, the four corner vertices. That is, the transformed coordinates obtained in the transformation step are further transformed based on the global alignment mark of the test sample. In this way, the second transformation unit performs a second transformation step in which the coordinates obtained by transforming the specific point coordinate values ​​using the calibration reference coordinates are further transformed into coordinates based on the global alignment marks, thereby enabling the position of the specific point to be acquired, identified, or managed with higher accuracy.

[0042] As shown in FIG. 7, alignment mark measurement is time-dependent. This is due to environmental changes such as temperature, humidity, and pressure within the device. Therefore, when measurements are taken from the upper left to the lower right grid in FIG. 7, the closer to the bottom right, the greater the deviation of the measurement point. Therefore, it is preferable for the acquisition unit 101 to acquire the coordinates of the alignment marks of the sections by correcting them with a function based on the elapsed time.

[0043] Furthermore, as shown in FIG. 8, when alignment marks are arranged in a grid pattern, it is preferable to measure adjacent columns of alignment marks in the same direction. For example, suppose that the coordinates of the alignment marks are measured with a time-dependent shift toward the lower right during a series of measurements. In this case, if the grid columns are scanned in a zigzag fashion, such as scanning the first column in a first direction, the second column in a second direction opposite to the first direction, and the third column in the first direction, the column in the grid (the second column in the figure) will be measured closer to the center. However, by scanning adjacent columns in the same direction (i.e., scanning the first, second, and third columns in the first direction), the center column is measured with a uniform shift, resulting in less distortion. This results in a uniform shift in the alignment mark coordinates of the four points in a section, which results in more accurate coordinates of the specific point after coordinate transformation based on the alignment mark coordinates of the section.

[0044] The acquisition unit 101 can reduce measurement errors by scanning and measuring the coordinates of adjacent rows of alignment marks in the section in the same direction. Note that the acquisition unit 101 may measure the coordinates of multiple adjacent rows of multiple alignment marks in the same direction, and in this case, it may scan and measure all rows in the same direction.

[0045] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the grid is represented by a square, but it may be a circle, a triangle, or other shape. Furthermore, the outermost alignment marks are represented by four points, but they may be more than four. [Explanation of symbols]

[0046] 100 information processing device, 101 acquisition unit, 102 recording unit, 901 processor, 902 memory

Claims

1. an acquiring step of acquiring the coordinates of alignment marks of a plurality of sections of a calibration sample having an area defined by four alignment marks; a recording step of calculating, for each of the sections, a coefficient for converting a region included in the section into a coordinate system based on the coordinates of the alignment mark of the section, and recording the coefficient in association with the section; determining which of the plurality of compartments in the calibration sample a particular point in the test sample belongs to; a reading step of reading the coefficients associated with the partition determined to belong to the partition; a transformation step of transforming the coordinates of the specific point based on the coefficients; An information processing method comprising:

2. The information processing method according to claim 1 , further comprising the step of acquiring the coordinates of the alignment marks of the sections by correcting them with a function based on elapsed time.

3. 2. The information processing method according to claim 1, further comprising the step of measuring the coordinates of adjacent rows of alignment marks in the section by scanning in the same direction.

4. a second transformation step of further transforming the transformed coordinates obtained in the transformation step based on a global alignment mark of the inspection sample; The information processing method according to claim 1 , comprising:

5. The coordinate transformation is a Helmert transformation, an affine transformation, or a homography transformation. The information processing method according to any one of claims 1 to 4.

6. an acquisition unit that acquires coordinates of alignment marks of a plurality of sections of a calibration sample having an area defined by four alignment marks; a recording unit that calculates, for each of the sections, a coefficient for converting a region included in the section into a coordinate system based on the coordinates of the alignment mark of the section, and records the coefficient in association with the section; a determination unit that determines to which of a plurality of sections in the calibration sample a particular point in the test sample belongs; a reading unit that reads out the coefficients associated with the partitions that are determined to belong to the image; a conversion unit that converts the coordinates of the specific point based on the coefficient; An information processing device comprising:

7. The information processing apparatus according to claim 6 , further comprising: the acquiring unit acquiring the coordinates of the alignment marks of the sections by correcting them with a function based on elapsed time.

8. The information processing apparatus according to claim 6 , further comprising: the acquisition unit measuring the coordinates of adjacent rows of alignment marks in the section by scanning in the same direction.

9. a second conversion unit that further converts the converted coordinates obtained by the conversion unit based on a global alignment mark of the inspection sample; The information processing device according to claim 6 , comprising:

10. The coordinate transformation is a Helmert transformation, an affine transformation, or a homography transformation. The information processing device according to claim 6 .

Images