A method for determining the value of a standard sample with a high aspect ratio groove

Abstract

The present invention provides a method for determining the value of a standard template for a high aspect ratio groove. The method comprises: dividing a wafer having high aspect ratio grooves prepared thereon into multiple standard grids; dividing each standard grid into n×n standard templates; cutting the central template of each standard grid, performing transverse slicing perpendicular to the groove direction, and measuring the groove dimensions of each slice; if the groove dimension uniformity of each slice of the central template is lower than a preset value, the standard templates divided by the standard grid containing the central template are deemed qualified, the groove dimensions of non-central templates of the standard grid are measured, and the values ​​of each standard template of the standard grid are obtained based on the measurement results. By measuring the uniformity of the central templates of each standard grid, the present invention can slice and determine the value of only the portion of the wafer with good uniformity, thereby improving the reliability of the standard template determination, avoiding slicing and measuring portions with poor uniformity, and improving the efficiency of the standard template determination.

Description

Technical Field

[0001] The present invention relates to the field of nano-metrology technology, and in particular to a method for determining the value of a high aspect ratio groove standard template. Background Art

[0002] Silicon-based MEMS (Microelectro Mechanical Systems) devices contain a large number of high aspect ratio structures. The aspect ratio of MEMS high aspect ratio structures is generally between 10:1 and 100:1, and the groove width is a few microns to tens of microns, which makes measurement difficult. As MEMS devices continue to develop towards high integration and low power consumption, the use of high aspect ratio structures is becoming more and more widespread, and there is an urgent need for fast non-destructive measurement technology and equipment for high aspect ratio structures. At present, the non-destructive measurement technology of silicon-based MEMS high aspect ratio structures mainly includes white light microscopy interferometry, laser confocal microscopy, low coherence interferometry spectroscopy and near-infrared wide-spectrum interferometry microscopy measurement technology.

[0003] A nondestructive measurement system based on near-infrared broadband interferometry microscopy (NIRBIMS) can measure aspect ratios up to 30:1. The NIRBIMS system is calibrated using a standard sample with a high-aspect-ratio groove structure. The groove widths of the standard sample range from 2μm to 30μm, and the depths range from 60μm to 300μm. The groove aspect ratio is greater than 10:1, with a maximum of 30:1. Before use, the standard sample must be calibrated to determine its groove width and depth. Existing techniques use silicon wafers to fabricate high-aspect-ratio groove structures. These samples are then cut into individual standard samples, sliced, and the groove width and depth are measured using a scanning electron microscope (SEM) to complete the calibration. If the calibration results for each standard sample vary significantly, the reliability of the calibration results cannot be determined, and the sample with such a large deviation is discarded, reducing the efficiency of the calibration process. Summary of the Invention

[0004] An embodiment of the present invention provides a method for determining the value of a high aspect ratio groove standard template to solve the problems of low reliability and low efficiency of the determination results of the high aspect ratio groove standard template in the prior art.

[0005] In a first aspect, an embodiment of the present invention provides a high aspect ratio trench standard template, comprising:

[0006] Dividing the wafer on which high aspect ratio trenches have been prepared into multiple standard grids;

[0007] Each standard grid is divided into n×n standard templates, where n is an odd number greater than 2, and the template located in the center of the n×n standard templates is the center template;

[0008] Cut the central template of each standard grid, make transverse slices perpendicular to the groove direction, and measure the groove size of each slice;

[0009] Calculate the uniformity of the groove size of each slice of the central sample;

[0010] If the groove size uniformity of each slice of the central template is lower than the preset value, then the standard templates divided by the standard grid where the central template is located are deemed qualified, and the groove size of the non-central templates of the standard grid is measured, and the fixed values ​​of each standard template of the standard grid are obtained based on the measurement results.

[0011] In a possible implementation, if the groove size uniformity of each slice of the central template is not less than a preset value, then each standard template divided by the standard grid where the central template is located is deemed unqualified.

[0012] In a possible implementation, cutting the central template of each standard grid, performing transverse slicing perpendicular to the groove direction, and measuring the groove size of each slice includes:

[0013] The center template of each standard grid is cut, and transverse slices are made perpendicular to the groove direction at the same interval, and the groove size of each slice is measured.

[0014] In a possible implementation, calculating the uniformity of the groove size of each slice of the central template includes:

[0015] The standard deviation of the groove size of each slice of the central sample was calculated using the Bessel formula to obtain the groove size uniformity.

[0016] In a possible implementation, calculating the uniformity of the groove size of each slice of the central template includes:

[0017] The groove size uniformity is obtained by calculating the difference between the maximum values ​​of the groove sizes of each slice of the central template and dividing it by the sum of the maximum values, wherein the difference between the maximum values ​​is the maximum value minus the minimum value of the groove size, and the sum of the maximum values ​​is the maximum value plus the minimum value of the groove size.

[0018] In a possible implementation, measuring the groove dimensions of the non-center template of the standard grid and obtaining the fixed values ​​of each standard template of the standard grid according to the measurement results includes:

[0019] Obtaining groove cross-sectional images of non-central sample slices;

[0020] Gaussian filtering is used to denoise the groove cross-section image;

[0021] Identify line edges in the groove cross-section image using a rectangular edge detection algorithm to obtain a feature map;

[0022] According to the line edges of the feature map, the measurement results of the groove size are obtained;

[0023] The fixed value of the non-center sample is obtained according to the measurement results.

[0024] In a possible implementation, identifying line edges in the groove cross-sectional image using a rectangular edge detection algorithm to obtain a feature map includes:

[0025] Obtaining line edges by performing gradient calculation on the grayscale values ​​of pixels in the groove cross-section image;

[0026] By performing high and low threshold determination on the grayscale values ​​of the pixels at the edge of the line, false edges at the edge of the line are reduced to obtain a feature map.

[0027] In a possible implementation, obtaining a groove cross-sectional image of a non-central sample slice includes:

[0028] The non-center sample is sliced, and a groove cross-sectional image of the non-center sample slice is obtained by scanning electron microscopy or atomic force microscopy.

[0029] In a possible implementation, the high aspect ratio trench dimensions include a trench width dimension and a trench depth dimension.

[0030] In a possible implementation, n is 5; the number of slices is 4.

[0031] An embodiment of the present invention provides a method for determining the value of a standard template for a high aspect ratio groove, comprising: dividing a wafer on which high aspect ratio grooves have been prepared into multiple standard grids; dividing each standard grid into n×n standard templates, wherein n is an odd number greater than 2, and the template located at the center of the n×n standard templates is a center template; cutting the center template of each standard grid, performing transverse slicing perpendicular to the groove direction, and measuring the groove size of each slice; calculating the uniformity of the groove size of each slice of the center template; if the groove size uniformity of each slice of the center template is lower than a preset value, determining that each standard template divided by the standard grid where the center template is located is qualified, measuring the groove size of non-center templates of the standard grid, and obtaining the determined value of each standard template of the standard grid based on the measurement results. By measuring the uniformity of the center templates of each standard grid, only the parts with good uniformity in the wafer are sliced ​​and calibrated. On the one hand, the parts with poor uniformity are eliminated, which improves the reliability of the standard template calibration. On the other hand, slicing and measuring the parts with poor uniformity are avoided, which improves the work efficiency of the standard template calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 This is a flow chart of a method for determining a value of a high aspect ratio trench standard template provided by an embodiment of the present invention;

[0034] Figure 2 is a schematic diagram of dividing a wafer into a standard grid according to an embodiment of the present invention;

[0035] Figure 3 is a schematic diagram of dividing a standard grid into standard templates provided by an embodiment of the present invention;

[0036] Figure 4 is a schematic top view of the groove structure provided by an embodiment of the present invention;

[0037] Figure 5 3 is a schematic diagram of the cross-sectional structure of the groove structure provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0038] To help those skilled in the art better understand this solution, the following will clearly describe the technical solutions in the embodiments of this solution in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of this solution, not all of it. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of this solution.

[0039] Throughout the specification, claims, and accompanying figures of this solution, the term "including" and any variations thereof mean "including, but not limited to," and are intended to cover non-exclusive inclusions and are not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish between different objects, not to describe a specific order.

[0040] The following is a detailed description of the implementation of the present invention with reference to the accompanying drawings:

[0041] This nondestructive measurement system, based on near-infrared broadband interferometry microscopy, boasts an aspect ratio range of up to 30:1. Calibration of the near-infrared broadband interferometry microscopy system utilizes a standard sample with a high-aspect-ratio groove structure. The groove widths of the standard sample range from 2μm to 30μm, and the depths from 60μm to 300μm. The aspect ratio is greater than 10:1, with a maximum range of 30:1. Before use, the standard sample must be calibrated to determine the groove width and depth.

[0042] Existing technology uses silicon wafers to fabricate high-aspect-ratio trench structures. After the high-aspect-ratio trench structures are fabricated, the wafers are cut into individual units, known as standard templates. The standard templates are sliced, and the width and depth of the trench structures in the slices are measured using a scanning electron microscope (SEM). These measured widths and depths are used as the fixed values ​​for the standard templates. If the fixed value results for each standard template vary significantly, the reliability of the standard template fixed value cannot be determined, and the standard template with large deviations is discarded, reducing the efficiency of the fixed value work.

[0043] Figure 1 A flow chart of a method for determining the value of a high aspect ratio trench standard template provided by an embodiment of the present invention. Figure 1 , the method comprising:

[0044] In step S1 , a wafer 1 on which high aspect ratio trenches have been fabricated is divided into a plurality of standard grids 2 .

[0045] Figure 2 Schematic diagram of a standard grid-divided wafer according to an embodiment of the present invention; Figure 2 :

[0046] Multiple standard grids 2 are arranged in a two-dimensional matrix on the same plane. The standard grids 2 are rectangular grids of equal size. The edges of the rectangular grids are parallel or perpendicular to the direction of the grooves. For example, the edges of the rectangular grids are parallel or perpendicular to the positioning edges of the wafer 1.

[0047] In step S2 , each standard grid 2 is divided into n×n standard templates 3 , wherein n is an odd number greater than 2, and the template located at the center of the n×n standard templates 3 is the central template 31 .

[0048] Figure 3 Schematic diagram of a standard grid 2 divided into a standard template 3 according to an embodiment of the present invention; Figure 4 is a schematic top view of the groove structure provided by an embodiment of the present invention; Figure 5 is a schematic diagram of the cross-sectional structure of the groove structure provided by an embodiment of the present invention; Figures 3 to 5 :

[0049] Each standard grid 2 is divided into n×n standard templates 3, that is, one standard grid 2 contains n×n standard templates 3. The width of the standard grid 2 is the width of the standard template 3 multiplied by n. The length of the standard grid 2 is the length of the standard template 3 multiplied by n.

[0050] For example, each standard grid 2 is divided into 5×5 standard templates 3. The template located at the exact center of the 5×5 standard templates 3 is the center template 31. That is, in the standard grid 2, the standard template 3 located at the intersection of the third horizontal row and the third vertical column is the center template 31.

[0051] In step S3 , the central template 31 of each standard grid 2 is cut and transversely sliced ​​perpendicular to the groove direction, and the groove size of each slice is measured.

[0052] The central template 31 of each standard grid 2 is cut, that is, the central template 31 of each grid is cut out from the wafer 1 .

[0053] In an optional embodiment, the cutting method is laser cutting.

[0054] The groove direction is parallel to the surface of the wafer 1 and parallel to the groove direction. Perpendicular to the groove direction means that the slice section is perpendicular to the surface of the wafer 1 and the groove direction is perpendicular to the slice section.

[0055] In an optional embodiment, n is 5. The number of slices is 4. That is, each standard grid 2 is divided into 5×5 standard templates 3. The central template 31 is transversely sliced ​​perpendicular to the groove direction to obtain 4 slices.

[0056] In an optional embodiment, the high aspect ratio trench dimensions include a trench width dimension and a trench depth dimension.

[0057] In an optional embodiment, the central template 31 of each standard grid 2 is cut, and transverse slices are performed perpendicular to the groove direction, and the groove size of each slice is measured, including: cutting the central template 31 of each standard grid 2, and transverse slices are performed perpendicular to the groove direction at the same interval, and the groove size of each slice is measured.

[0058] Exemplarily, the spacing is less than 0.5 mm. When the spacing is less than 0.5 mm, the thickness after slicing is less than 0.5 mm, which facilitates the measurement of the groove size of each slice using CD-SEM.

[0059] In step S4 , the uniformity of the size of each slicing groove of the central template 31 is calculated.

[0060] In an optional embodiment, calculating the uniformity of the groove size of each slice of the central template 31 includes: calculating the standard deviation of the groove size of each slice of the central template 31 by using the Bessel formula to obtain the groove size uniformity.

[0061] In an optional embodiment, calculating the uniformity of the groove size of each slice of the central template 31 includes: calculating the difference between the maximum values ​​of the groove size of each slice of the central template 31 and dividing it by the sum of the maximum values ​​to obtain the groove size uniformity, wherein the difference between the maximum values ​​is the maximum value minus the minimum value of the groove size, and the sum of the maximum values ​​is the maximum value plus the minimum value of the groove size.

[0062] The embodiment provided by the present invention divides the wafer into standard grids, measures and calculates the groove size uniformity of each central template 31, and can comprehensively evaluate the groove size uniformity of the entire wafer.

[0063] In step S5, if the groove size uniformity of each slice of the central template 31 is lower than the preset value, the standard templates 3 divided by the standard grid 2 where the central template 31 is located are deemed qualified, and the groove size of the non-central template 32 of the standard grid 2 is measured, and the fixed value of each standard template 3 of the standard grid 2 is obtained based on the measurement results.

[0064] If the size uniformity of each slicing groove of the central template 31 is lower than a preset value, a non-central template 32 is cut out from the wafer 1 .

[0065] In an optional embodiment, if the groove size uniformity of each slice of the central template 31 is not lower than a preset value, then the standard templates 3 divided by the standard grid 2 where the central template 31 is located are deemed unqualified.

[0066] High-aspect-ratio groove standard template 3 has high precision requirements. For example, the maximum allowable measurement error for a 2μm line width is ±0.03μm. For example, the maximum allowable measurement error for a 60μm depth is ±0.3μm. Using a scanning electron microscope, the groove dimensions were directly measured using measuring lines. The width of the measuring lines generally reached 1μm, far exceeding the maximum allowable measurement error requirements for standard template 3. Furthermore, the line edges in the image were blurred and difficult to distinguish, resulting in large direct measurement errors, affecting the accuracy of the measurement results.

[0067] In an optional embodiment, the groove size of the non-center template 32 of the standard grid 2 is measured, and the fixed value of each standard template 3 of the standard grid 2 is obtained according to the measurement result, including:

[0068] A groove cross-sectional image of 32 slices of the non-center template is obtained.

[0069] Gaussian filtering is used to denoise the groove cross-section image. M(x,y) represents the Gaussian function, which is expressed as follows:

[0070]

[0071] g(x,y) represents the groove cross-section image as input data. (x,y) represents the pixel point of the groove cross-section image at the coordinates x,y in the two-dimensional coordinates. g s (x,y) represents the groove cross-section image after denoising.

[0072] g s (x,y)=g(x,y)*M(x,y)

[0073] The rectangular edge detection algorithm is used to identify the line edges in the groove cross-section image and obtain the feature map. The core of rectangular edge detection is to detect line edges. The change of grayscale value in the groove cross-section image has a significant impact on the measurement results.

[0074] The trench dimensions are measured based on the line edges of the feature map. The trench dimensions are measured by measuring the distance between the lines representing the edges of the trench structure in the feature map. Exemplarily, the trench dimensions include trench width and trench depth.

[0075] The fixed value of the non-center template 32 is obtained based on the measurement result. The groove size measurement result is used as the fixed value result of the non-center template 32.

[0076] In an optional embodiment, identifying line edges in the groove cross-section image using a rectangular edge detection algorithm to obtain a feature map includes:

[0077] Line edges are obtained by performing gradient calculations on the grayscale values ​​of pixels in the groove cross-section image. A single pixel has pixels diagonally opposite it. The gradient calculation process involves convolving the operator with the pixels of the groove cross-section image, and then calculating the horizontal and vertical line edges of the image, and the gradient M and direction θ of that pixel.

[0078]

[0079] θ=arctan(M x / M y )

[0080] Where M represents the gradient magnitude; θ represents the gradient direction; arctan(M x / M y ) represents the inverse tangent function.

[0081] By performing high and low threshold judgments on the grayscale values ​​of the pixels on the edge of the line, the false edges on the edge of the line are reduced and a feature map is obtained. False edges are reduced in the form of high and low thresholds, that is, when the pixel is higher than the high threshold Y1, it will be retained as a strong edge of the image, when the pixel is lower than the low threshold Y2, it will be removed, and when the pixel is between the high threshold and the low threshold, it will be regarded as a weak edge of the image. If there is a strong edge pixel in the upper, lower, left, and right diagonal range of the pixel on the weak edge, then the pixel is retained as a strong edge pixel. If not, the pixel is removed. The relationship between Y1 and Y2 is as follows:

[0082] Y1=2Y2

[0083] The embodiment provided by the present invention processes the groove cross-section image through the above-mentioned standard template 3 fixed value algorithm, avoiding the influence of the measurement line width in direct measurement and the influence of the blurred image line edge, obtaining accurate line edges, and making the measurement result more accurate.

[0084] In an optional embodiment, obtaining a groove cross-sectional image of a slice of the non-center template 32 includes slicing the non-center template 32 and obtaining a groove cross-sectional image of the slice of the non-center template 32 using a scanning electron microscope or an atomic force microscope.

[0085] In an optional embodiment, the central template 31 of each standard grid 2 is cut and transversely sliced ​​perpendicular to the groove direction, and the groove size of each slice is measured, including:

[0086] The central template 31 of each standard grid 2 is cut and transversely sliced ​​perpendicular to the groove direction.

[0087] A groove cross-sectional image of a slice of the central template 31 is acquired.

[0088] Gaussian filtering is used to denoise the groove cross-section image.

[0089] The line edges in the groove cross-section image are identified by a rectangular edge detection algorithm to obtain a feature map.

[0090] According to the line edges of the feature map, the measurement results of the groove size of each slice are obtained.

[0091] In an optional embodiment, the standard template 3 includes a high aspect ratio groove structure, a groove auxiliary setting structure, an orthogonal scanning calibration structure, a measurement positioning structure, and a positioning angle structure. Exemplarily, the overall dimensions of the standard template 3 are 10 mm × 10 mm. Exemplarily, the depth dimension of the high aspect ratio groove structure is 300 μm, the width dimension is 30 μm, and the aspect ratio is 10:1. Exemplarily, the depth dimension of the high aspect ratio groove structure is 300 μm, the width dimension is 10 μm, and the aspect ratio is 30:1. Exemplarily, the depth dimension of the high aspect ratio groove structure is 150 μm, the width dimension is 5 μm, and the aspect ratio is 30:1. Exemplarily, the depth dimension of the high aspect ratio groove structure is 60 μm, the width dimension is 2 μm, and the aspect ratio is 30:1.

[0092] The embodiment provided by the present invention measures the uniformity of the central template 31 of each standard grid 2 and only slices and values ​​the part with good uniformity in the wafer 1. On the one hand, the part with poor uniformity is eliminated, thereby improving the reliability of the value setting of the standard template 3. On the other hand, slicing and measuring the part with poor uniformity is avoided, thereby improving the working efficiency of the value setting of the standard template 3.

[0093] In an optional embodiment, a wafer 1 on which high aspect ratio grooves have been prepared is divided into a plurality of standard grids 2, wherein the target width of the groove structure is 30 microns and the target depth is 300 microns. Each standard grid 2 is divided into 5×5 standard templates 3. The center template 31 of each standard grid 2 is cut, and each center template 31 is cut out from the wafer 1. Each center template 31 is sliced ​​transversely perpendicular to the groove direction to obtain three slices: upper, middle, and lower. The groove width and groove depth dimensions of each slice are measured. The same dimension of the same slice is measured multiple times, and the repeatability of the measurement is evaluated by the standard deviation. The measurement results of the groove dimensions of each slice of some center templates 31 are as follows:

[0094] Table 1: 1# center sample groove size measurement data

[0095]

[0096] Table 2: 2# center sample groove size measurement data

[0097]

[0098] Table 3: 3# center sample groove size measurement data

[0099]

[0100] Table 4: 4# center sample groove size measurement data

[0101]

[0102] Table 5: 5# center sample groove size measurement data

[0103]

[0104] Calculate the uniformity of the groove size of each slice of the central template 31. Exemplarily, for the 1# to 5# central templates 31, the uniformity of the groove depth size of each central template is 0.08%, 0.18%, 0.12%, 0.03% and 0.12%. If the groove size uniformity of each slice of the central template 31 is lower than the preset value, then the standard templates 3 divided by the standard grid 2 where the central template 31 is located are deemed qualified. Exemplarily, the above preset value is 0.12%, then the standard templates 3 divided by the standard grid 2 where the 1#, 2# and 4# central templates 31 are located are deemed qualified. Measure the groove size of the non-central template 32 of the standard grid 2, and obtain the fixed value of each standard template 3 of the standard grid 2 based on the measurement results.

[0105] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for determining the value of a standard sample of a high aspect ratio groove, characterized in that: include: Dividing the wafer on which high aspect ratio trenches have been prepared into multiple standard grids; Each standard grid is divided into n×n standard templates, where n is an odd number greater than 2, and the template located in the center of the n×n standard templates is the center template; Cut the central template of each standard grid, make transverse slices perpendicular to the groove direction, and measure the groove size of each slice; Calculate the uniformity of the groove size of each slice of the central sample; If the groove size uniformity of each slice of the central template is lower than the preset value, the standard templates divided by the standard grid where the central template is located are deemed qualified, the groove size of the non-central templates of the standard grid is measured, and the fixed values ​​of each standard template of the standard grid are obtained based on the measurement results, wherein the fixed values ​​include groove width and groove depth.

2. The method for determining the value of a high aspect ratio trench standard template according to claim 1, wherein: Also includes: If the groove size uniformity of each slice of the central template is not lower than the preset value, then the standard templates divided by the standard grid where the central template is located are deemed unqualified.

3. The method for determining the value of a high aspect ratio trench standard template according to claim 1, wherein: The central template of each standard grid is cut, and horizontal slices are made perpendicular to the groove direction, and the groove size of each slice is measured, including: The center template of each standard grid is cut, and transverse slices are made perpendicular to the groove direction at the same interval, and the groove size of each slice is measured.

4. The method for determining the value of a high aspect ratio trench standard template according to claim 1, wherein: The calculation of the uniformity of the groove size of each slice of the central template includes: The standard deviation of the groove size of each slice of the central sample was calculated using the Bessel formula to obtain the groove size uniformity.

5. The method for determining the value of a high aspect ratio trench standard template according to claim 1, wherein: The calculation of the uniformity of the groove size of each slice of the central template includes: The groove size uniformity is obtained by calculating the difference between the maximum values ​​of the groove sizes of each slice of the central template and dividing it by the sum of the maximum values, wherein the difference between the maximum values ​​is the maximum value minus the minimum value of the groove size, and the sum of the maximum values ​​is the maximum value plus the minimum value of the groove size.

6. The method for determining the value of a high aspect ratio trench standard template according to claim 1, wherein: The method of measuring the groove size of the non-center template of the standard grid and obtaining the fixed value of each standard template of the standard grid according to the measurement result includes: Obtaining groove cross-sectional images of non-central sample slices; Gaussian filtering is used to denoise the groove cross-section image; Identify line edges in the groove cross-section image using a rectangular edge detection algorithm to obtain a feature map; According to the line edges of the feature map, the measurement results of the groove size are obtained; The fixed value of the non-center sample is obtained according to the measurement results.

7. The method for determining the value of a high aspect ratio trench standard template according to claim 6, wherein: The identifying line edges in the groove cross-section image by using a rectangular edge detection algorithm to obtain a feature map includes: Obtaining line edges by performing gradient calculation on the grayscale values ​​of pixels in the groove cross-section image; By performing high and low threshold determination on the grayscale values ​​of the pixels at the edge of the line, false edges at the edge of the line are reduced to obtain a feature map.

8. The method for determining the value of a high aspect ratio trench standard template according to claim 7, wherein: The step of obtaining a groove cross-sectional image of a non-central sample slice comprises: The non-center sample is sliced, and a groove cross-sectional image of the non-center sample slice is obtained by scanning electron microscopy or atomic force microscopy.

9. The method for determining the value of a high aspect ratio trench standard template according to claim 1, wherein: The n is 5; the number of slices is 4.

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