Linear cutting damage depth measuring method and system

Abstract

The invention provides a method and system for measuring the damage depth of linear cutting, and the method and system are used for measuring the damage depth of a silicon wafer after linear cutting, and the method comprises the steps: determining a transition region between the outer surface of the silicon wafer and a damage region; an upper boundary line and a lower boundary line of the transition area are parallel to each other, and the upper boundary line and the lower boundary line are determined according to the line mark direction and the position information of the damage point; constructing a boundary which is parallel to the upper boundary and equally divides the transition area; constructing a damage termination line parallel to the boundary line through the Nth damage point in the damage area; and measuring the distance between the boundary and the damage termination line as the damage depth of the silicon wafer. According to the method, by defining the transition area and defining the standards of the boundary and the damage termination line, the problems of boundary fuzziness and data errors existing in damage depth measurement are solved, the measurement accuracy and repeatability are improved, the measurement instability caused by accidental errors is reduced, and the application type is wide.

Description

Technical Field

[0001] The present application relates to the technical field of silicon wafer surface detection, and in particular to a method and system for measuring wire cutting damage depth. Background Art

[0002] In the field of semiconductor manufacturing, the quality of silicon wafers directly affects the subsequent chip manufacturing process and the performance of the final product. In the wire cutting process, for example, diamond wire, mortar wire, etc. are used to cut silicon wafers. Although these wire cutting technologies have the advantages of high efficiency and high processing precision, they will damage the surface of the silicon wafer during the cutting process. These damages will affect the performance of the silicon wafer, and then affect the reliability and service life of the entire semiconductor device. Therefore, it is necessary to quantitatively measure the damage depth of wire cutting. Most of the related wire cutting evaluation methods focus on their morphology. Although the damage depth is also involved, the data deviation is often large due to its unclear evaluation specifications. The main reasons are: the boundary between the outer surface and the damaged area is difficult to judge; there is no unified standard for judging the damage termination line; researchers ignore the importance of the direction of the wire mark.

[0003] Based on this, the present application provides a method and system for measuring wire cutting damage depth to improve related technologies. Summary of the invention

[0004] The purpose of the present application is to provide a method and system for measuring the damage depth of wire cutting, so as to accurately measure the damage depth of silicon wafers after wire cutting.

[0005] The purpose of this application is achieved by the following technical solutions:

[0006] In a first aspect, the present application provides a method for measuring the damage depth of wire cutting, which is used to measure the damage depth of a silicon wafer after wire cutting, the method comprising: determining a transition zone between the outer surface of the silicon wafer and the damage zone; the upper boundary line and the lower boundary line of the transition zone are parallel to each other, and the upper boundary line and the lower boundary line are determined according to the line mark direction and the position information of the damage point; constructing a dividing line parallel to the upper boundary line and bisecting the transition zone; constructing a damage stop line parallel to the dividing line through the Nth to last damage point in the damage zone; N is a positive integer; measuring the distance between the dividing line and the damage stop line as the damage depth of the silicon wafer.

[0007] In some embodiments, the wire cutting is diamond wire cutting; the upper boundary of the transition zone passes through the first line mark termination point in the transition zone and forms a first target angle with the line mark direction; the lower boundary of the transition zone passes through the target line mark termination point in the transition zone and is parallel to the upper boundary; the target line mark termination point is determined according to the position distribution range of the line mark termination point.

[0008] In some embodiments, the first target angle ranges from 35 degrees to 55 degrees.

[0009] In some embodiments, the ratio of the number of line mark termination points in the transition zone to the total number of line mark termination points is a first target ratio; the first target ratio ranges from 70% to 90%.

[0010] In some embodiments, the line cutting is mortar line cutting or structural line cutting; the upper boundary of the transition zone passes through the first damage point in the transition zone and forms a second target angle with the line mark direction; the lower boundary of the transition zone passes through the target damage point in the transition zone and is parallel to the upper boundary; the target damage point is determined according to the position distribution range of the damage point.

[0011] In some embodiments, the second target angle ranges from 80 degrees to 90 degrees.

[0012] In some embodiments, the ratio of the number of damage points in the transition zone to the total number of damage points is a second target ratio; the second target ratio ranges from 70% to 90%.

[0013] In a second aspect, the present application provides a wire cutting damage depth measurement system for measuring the damage depth of a silicon wafer after wire cutting. The system includes a control module, and the control module is used to execute any of the above methods.

[0014] The present application provides a method and system for measuring the damage depth of wire cutting, establishes a transition zone between the outer surface of the silicon wafer and the damaged area, and constructs a dividing line and a damage termination line in the transition zone to accurately measure the damage depth. Specifically, the method first determines the upper and lower boundaries of the transition zone according to the direction of the line mark and the position information of the damage point. Then, a dividing line parallel to the upper boundary and bisecting the transition zone is constructed to accurately divide the outer surface of the silicon wafer and the damaged area. By observing the position of the Nth last damage point in the damage area, a damage termination line parallel to the dividing line is constructed to ensure the stability of the measurement of the damage depth. Next, by measuring the distance between the dividing line and the damage termination line, the damage depth of the silicon wafer is obtained, thereby realizing the quantitative analysis of the damage depth of the silicon wafer wire cutting. The present application improves the boundary fuzziness and data error problems existing in the measurement of the damage depth by defining the transition zone and clarifying the standards of the dividing line and the damage termination line. Secondly, by making full use of the information of the line mark direction, the damage distribution in the transition zone is more uniform, and the data deviation is significantly reduced, thereby improving the accuracy and repeatability of the measurement. In addition, according to the needs of practical applications, the Nth last damage point is flexibly selected as the termination point, which effectively reduces the measurement instability caused by accidental errors and is suitable for damage depth measurement in different types of wire cutting processes. This application provides an efficient and stable damage depth measurement solution, which is convenient for reasonably evaluating the damage depth of silicon wafer wire cutting and helps the quality control of silicon wafer processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present application is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0016] Figure 1 It is a flow chart of a method for measuring wire cutting damage depth provided in an embodiment of the present application.

[0017] Figure 2 This is a damage depth map of diamond wire cutting provided in an embodiment of the present application.

[0018] Figure 3a This is a damage depth map of diamond wire cutting provided in an embodiment of the present application (the direction of the wire mark is 0 degrees to the dividing line).

[0019] Figure 3b This is a damage depth map of diamond wire cutting provided in an embodiment of the present application (the direction of the wire mark is 30 degrees to the dividing line).

[0020] Figure 3c This is a damage depth map of diamond wire cutting provided in an embodiment of the present application (the direction of the wire mark is 45 degrees to the dividing line).

[0021] Figure 3d This is a damage depth map of diamond wire cutting provided in an embodiment of the present application (the direction of the wire mark is 60 degrees to the dividing line).

[0022] Figure 3e This is a damage depth map of diamond wire cutting provided in an embodiment of the present application (the direction of the wire mark is 90 degrees to the dividing line).

[0023] Figure 4 This is a damage depth map of mortar wire cutting provided in an embodiment of the present application.

[0024] Figure 5a This is a damage depth map of a mortar line cutting provided in an embodiment of the present application (the line mark direction is 0 degrees to the dividing line).

[0025] Figure 5b This is a damage depth map of a mortar line cutting provided in an embodiment of the present application (the line mark direction is 30 degrees to the dividing line).

[0026] Figure 5c This is a damage depth map of a mortar line cutting provided in an embodiment of the present application (the line mark direction is 45 degrees to the dividing line).

[0027] Figure 5d This is a damage depth map of a mortar line cutting provided in an embodiment of the present application (the line mark direction is 60 degrees to the dividing line).

[0028] Figure 5e It is a damage depth map of a mortar line cutting provided in an embodiment of the present application (the line mark direction is 90 degrees to the dividing line).

[0029] Figure 6 It is a damage depth box plot of diamond wire cutting provided in an embodiment of the present application.

[0030] Figure 7 It is a damage depth box plot of mortar wire cutting provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in this application to clearly and completely describe the technical solutions in the implementation mode of this application. Obviously, the described implementation mode is only a part of the implementation mode of this application, not all the implementation modes. Based on the implementation mode in this application, all other implementation modes obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0032] In the description of the embodiments of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0033] The shape and nano-morphology of silicon wafers depend on the process conditions of wire cutting. More and more advanced wire cutting processes such as mortar wire, structural wire, and diamond wire have become the main processing methods in the silicon wafer forming process, and have significant advantages due to their fast and efficient characteristics. Most of the related wire cutting evaluation methods focus on their morphology. Although the damage depth is also involved, the data deviation is often large due to unclear evaluation standards. The main reasons are: the boundary between the outer surface and the damaged area is difficult to judge; there is no unified standard for judging the damage termination line; and researchers ignore the importance of the wire mark direction.

[0034] The implementation methods of the present application will be described in detail below.

[0035] See also Figure 1 , Figure 1 It is a flow chart of a method for measuring wire cutting damage depth provided in an embodiment of the present application.

[0036] An embodiment of the present application provides a method for measuring the damage depth of wire cutting, which is used to measure the damage depth of a silicon wafer after wire cutting. The method includes steps S101 to S104.

[0037] Step S101: determining a transition zone between the outer surface of the silicon wafer and the damaged zone; the upper boundary and the lower boundary of the transition zone are parallel to each other, and the upper boundary and the lower boundary are determined according to the line mark direction and the position information of the damage point.

[0038] Step S102: constructing a boundary line parallel to the upper boundary line and bisecting the transition area.

[0039] Step S103: construct a damage termination line parallel to the boundary line through the Nth last damage point in the damage area; N is a positive integer.

[0040] Step S104: measuring the distance between the boundary line and the damage stop line as the damage depth of the silicon wafer.

[0041] In the above embodiment, the transition zone between the outer surface and the damaged area is first determined. For example, the transition zone can be defined as an area where both the line marks and the damage exist. The dividing line is the dividing line between the outer surface and the damaged area, which is parallel to the upper boundary line and divides the transition zone equally. The dividing line is located at 1 / 2 of the transition zone, and the distance between the dividing line and the upper boundary line is equal to the distance between the dividing line and the lower boundary line. The above embodiment uses the upper boundary line and the lower boundary line to define the transition zone between the outer surface and the damaged area, and the upper boundary line and the lower boundary line can be determined according to the line mark direction and the position information of the damage point.

[0042] After the silicon wafer is cut online, multiple damage points will be formed. Some of these damage points are line mark termination points, and some are ordinary damage points other than line mark termination points. In other words, the line mark termination points can be regarded as a subset of damage points. Select the last damage point (i.e., the damage point farthest from the outer surface), the N-1th damage point observed in the damage area, that is, the Nth damage point from the end, and construct a straight line passing through the damage point and parallel to the dividing line as the damage termination line. The above embodiment does not limit N, and N is, for example, 2, 3, 4, 5, 10, etc.

[0043] The above embodiment fixes the standard of the boundary line between the outer surface and the damaged area, fixes the standard of the damage termination line, and fixes the line mark direction, so that the high and low efficiency grinding surfaces are evenly distributed, which is convenient for accurately identifying the damage depth.

[0044] See also Figure 2 , Figures 3a to 3e , Figure 2 is a damage depth map of diamond wire cutting provided by an embodiment of the present application, Figure 3a This is a damage depth map of a diamond wire cutting provided in an embodiment of the present application (the direction of the wire mark is 0 degrees to the dividing line). Figure 3b This is a damage depth map of a diamond wire cutting provided in an embodiment of the present application (the direction of the wire mark is 30 degrees to the dividing line). Figure 3c This is a damage depth map of a diamond wire cutting provided in an embodiment of the present application (the direction of the wire mark is 45 degrees to the dividing line). Figure 3d This is a damage depth map of a diamond wire cutting provided in an embodiment of the present application (the direction of the wire mark is 60 degrees to the dividing line). Figure 3e This is a damage depth map of diamond wire cutting provided in an embodiment of the present application (the direction of the wire mark is 90 degrees to the dividing line).

[0045] In some embodiments, the wire cutting can be diamond wire cutting; the upper boundary of the transition zone passes through the first line mark termination point in the transition zone and forms a first target angle with the line mark direction; the lower boundary of the transition zone passes through the target line mark termination point in the transition zone and is parallel to the upper boundary; the target line mark termination point is determined according to the position distribution range of the line mark termination point.

[0046] In the above embodiment, the upper boundary line is defined by the passing point and direction, and the point is the first line mark termination point in the transition zone, that is, the line mark termination point closest to the outer surface. The upper boundary line passes through the first line mark termination point in the transition zone, and the direction of the upper boundary line forms a first target angle with the line mark direction. The lower boundary line can also be defined by the passing point and direction, and the point is the target line mark termination point in the transition zone, for example, a line mark termination point determined according to the position distribution range of the line mark termination point. The lower boundary line passes through the target line mark termination point and is parallel to the upper boundary line.

[0047] The above embodiment does not limit the first target angle between the upper boundary and the line mark direction. In some embodiments, the first target angle may be in the range of 35 to 55 degrees. As an example, the first target angle may be 35, 40, 45, 50, 55, etc.

[0048] Diamond wire has its unique properties, that is, wire marks are the main form of damage, and different wire mark depths are the main cause of its damage. Therefore, it is necessary to adjust the termination lines of wire marks of different depths to be evenly distributed on the test surface. In order to adjust the uniform distribution of wire marks, it is very important to choose a suitable test angle (that is, the first target angle between the upper boundary and the wire mark direction). When the first target angle is around 45°, its transition zone is narrow, and the standard deviation of the reading is the smallest at this time. When the value range of the first target angle is expanded to 35 degrees to 55 degrees, the standard deviation within this value range is small, and it can reflect the actual situation.

[0049] In some embodiments, the ratio of the number of line mark termination points in the transition zone to the total number of line mark termination points may be a first target ratio. The above embodiments do not limit the first target ratio. In some embodiments, the value range of the first target ratio may be 70% to 90%. As an example, the first target ratio may be 70%, 80%, 85%, 90%, etc. From the experience of practical applications, it can be concluded that when the first target ratio is less than 70%, the damage transition zone will be too narrow and the damage depth will be too large; when the second target ratio is greater than 90%, the damage transition zone will be too wide and the damage depth will be too small. Therefore, the value range of the second target ratio is set to 70% to 90%. Within this value range, a suitable transition zone width can be achieved, thereby accurately evaluating the damage depth.

[0050] The total number of line mark termination points refers to the sum of the number of line mark termination points in the transition zone and the number of line mark termination points outside the transition zone. As an example, the number of line mark termination points in the transition zone is 80, and the number of line mark termination points outside the transition zone is 20, then the total number of line mark termination points is 100, and the ratio of the number of line mark termination points in the transition zone to the total number of line mark termination points is 80%.

[0051] like Figure 2 As shown, taking diamond wire cutting as an example, first, the standard of the boundary line between the outer surface and the damaged area is fixed. Specifically, the upper boundary of the transition zone can be determined by the position of the line mark termination point that has just appeared (that is, the position of the first line mark termination point) and the line mark direction; the lower boundary of the transition zone is parallel to the upper boundary, and can be determined by 80% of the line mark termination points (the corresponding transition zone contains 80% of the line mark termination points). Then, select 1 / 2 of the transition zone as the boundary line between the outer surface and the damaged area. Secondly, fix the damage termination line standard. Specifically, select the last damage point, observe the damage point in the damage area, and construct a straight line passing through the third to last damage point and parallel to the dividing line as the damage termination line. Since the angle between the line mark direction and the dividing line (which can be called the line mark angle) is a fixed value, that is, the first target angle, the high and low efficiency grinding surfaces can be evenly distributed.

[0052] like Figures 3a to 3e As shown, after a large number of tests, the applicant found that the line direction of diamond wire cutting has a significant effect on the width of the transition zone. Reasonable selection of the angle between the line direction and the dividing line (i.e., the first target angle) can minimize the width of the transition zone. In a specific application scenario of diamond wire cutting, when the angle between the line direction and the dividing line is 45° (° is a degree, an angle unit), the transition zone is the shortest, the high-efficiency grinding surface and the low-efficiency grinding surface are most evenly distributed, and the observation result stability is the best.

[0053] The above embodiment considers the following aspects in selecting the corresponding dividing line for diamond wire cutting. Figure 2 As can be seen in the figure, for the boundary line between the outer surface and the damaged area, since the depth of the line marks is uneven and the surface morphology change is difficult to determine, a transition zone can be delineated. For example, the end point of the line marks just appearing and the end point of 80% of the line marks are defined as the upper and lower boundaries of the transition zone. The two are parallel to each other and both form the first target angle with the line mark direction. It is difficult to distinguish the outer surface from the damaged area in this transition zone, so 1 / 2 of the transition zone can be selected as the boundary line between the outer surface and the damaged area. For the end line of the damage depth (i.e., the damage end line), in order to reduce accidental errors, the third to last damage point in the silicon wafer can be selected as the damage end point, and the damage end line can be further defined. The selection of the angle between the line mark direction and the boundary line (i.e., the first target angle) can be summarized from a large amount of data. Its purpose is to make the distribution of different line marks more uniform so that the most obvious interface can be observed. This is extremely important for the identification of damage depth and ensures the accuracy of the data.

[0054] See also Figure 4 , Figure 5a to Figure 5e , Figure 4 is a damage depth map of a mortar wire cutting provided in an embodiment of the present application, Figure 5a This is a damage depth map of a mortar wire cutting provided in an embodiment of the present application (the line mark direction is 0 degrees to the dividing line). Figure 5b This is a damage depth map of a mortar wire cutting provided in an embodiment of the present application (the direction of the wire mark is 30 degrees to the dividing line). Figure 5c This is a damage depth map of a mortar wire cutting provided in an embodiment of the present application (the direction of the wire mark is 45 degrees to the dividing line). Figure 5d This is a damage depth map of a mortar wire cutting provided in an embodiment of the present application (the direction of the wire mark is 60 degrees to the dividing line). Figure 5e It is a damage depth map of a mortar line cutting provided in an embodiment of the present application (the line mark direction is 90 degrees to the dividing line).

[0055] In some embodiments, the line cutting can be mortar line cutting or structural line cutting; the upper boundary of the transition zone passes through the first damage point in the transition zone and forms a second target angle with the line mark direction; the lower boundary of the transition zone passes through the target damage point in the transition zone and is parallel to the upper boundary; the target damage point is determined according to the position distribution range of the damage point.

[0056] In the above embodiment, the upper boundary line is defined by the passing point and direction, and the point is the first damage point in the transition zone, that is, the damage point closest to the outer surface. The upper boundary line passes through the first damage point in the transition zone, and the direction of the upper boundary line forms a second target angle with the line mark direction. The lower boundary line can also be defined by the passing point and direction, and the point is a target damage point in the transition zone, for example, a damage point determined according to the position distribution range of the damage point. The lower boundary line passes through the target damage point and is parallel to the upper boundary line.

[0057] The above embodiment does not limit the second target angle between the upper boundary and the line mark direction. In some embodiments, the second target angle may be in the range of 80 to 90 degrees. As an example, the second target angle may be 80, 85, 90, etc.

[0058] The applicant has found in practice that when the second target angle between the upper boundary and the line mark direction is 90°, the edge of the transition zone between the outer surface and the damaged area is more obvious, and the central trend of the damage depth evaluation is most significant. At the same time, when the second target angle between the upper boundary and the line mark direction is 90°, the interface has the most line marks as the evaluation interface, which can truly reflect the damage situation. In other words, when the second target angle between the upper boundary and the line mark direction is 90°, its advantage is that the number of observable line marks is large enough to reduce the accidental errors in readings caused by small angles and single line marks. When it drops to 80°, the number of line marks can still be guaranteed to be sufficient, there is no small angle, and the accidental error is still small. Therefore, the value range of the second target angle can be expanded to 80 degrees to 90 degrees, and accidental errors can be reduced within this value range.

[0059] In some embodiments, the ratio of the number of damage points in the transition zone to the total number of damage points may be a second target ratio. The above embodiments do not limit the second target ratio. In some embodiments, the value range of the second target ratio may be 70% to 90%. As an example, the second target ratio may be 70%, 80%, 85%, 90%, etc. From the experience of practical applications, it can be concluded that when the second target ratio is less than 70%, the damage transition zone will be too narrow and the damage depth will be too large; when the second target ratio is greater than 90%, the damage transition zone will be too wide and the damage depth will be too small. Therefore, the value range of the second target ratio is set to 70% to 90%. Within this value range, a suitable transition zone width can be achieved, thereby accurately evaluating the damage depth.

[0060] like Figure 4 As shown, taking mortar line cutting as an example, first fix the standard of the boundary line between the outer surface and the damaged area. Specifically, the upper boundary of the transition zone can be determined by the position of the damage point that just appeared (that is, the position of the first damage point) and the direction of the line mark; the lower boundary of the transition zone is parallel to the upper boundary, and can be determined by 80% of the damage points (the corresponding transition zone contains 80% of the damage points). Then, select 1 / 2 of the transition zone as the boundary line between the outer surface and the damaged area. Secondly, fix the damage termination line standard. Specifically, select the last damage point, observe the damage point in the damage area, and construct a straight line passing through the third to last damage point and parallel to the dividing line as the damage termination line. Since the angle between the line mark direction and the dividing line is a fixed value, that is, the first target angle, the high and low efficiency grinding surfaces can be evenly distributed.

[0061] like Figure 5a to Figure 5eAs shown, after a large number of tests, the applicant found that the line direction of the mortar line cutting has a significant effect on the distribution of the grinding surface. Reasonable selection of the angle between the line direction and the dividing line (i.e., the second target angle) can minimize the alternation between the high-efficiency grinding surface and the low-efficiency grinding surface. In a specific application scenario of mortar line cutting, when the angle between the line direction and the dividing line is 90°, there is only a high-efficiency grinding surface or a low-efficiency grinding surface, and the observation result stability is the best.

[0062] The above embodiment considers the following aspects in selecting the corresponding dividing line for mortar line cutting. Figure 4 It can be seen that the line width of the mortar wire is wider than that of the diamond wire, so the selection rules are different from those of the diamond wire cutting. Figure 4 Obviously, point-shaped damage areas can be seen in the image, so they can be used as a basis for judgment. Specific selection rules can be selected according to actual needs. Similarly, the selection of the angle between the line mark direction and the dividing line (i.e., the second target angle) can be obtained by summarizing a large amount of data. The purpose is to make the distribution of different damages more uniform so as to observe the most obvious interface. This is extremely important for the identification of damage depth and ensures the accuracy of the data.

[0063] See also Figure 6 and Figure 7 , Figure 6 is a damage depth box plot of diamond wire cutting provided in an embodiment of the present application, Figure 7 It is a damage depth box plot of mortar wire cutting provided in an embodiment of the present application.

[0064] Based on the above technical means and rules, the applicant tested and obtained the following damage depths of diamond wire cutting and mortar wire cutting.

[0065] Table 1 Comparison of damage depth of diamond wire at different line mark angles

[0066] Line mark angle / ° 0 30 35 45 55 60 90 Damage mean / 0.1μm 25.17 30.80 30.93 31.40 35.62 67.39 39.70 Damage standard deviation 4.25 5.33 4.20 3.46 4.38 14.99 12.17 Number of samples / ea 10 10 10 10 10 10 10

[0067] Table 2 Comparison of damage depth of mortar lines at different line mark angles

[0068] Line mark angle / ° 0 30 45 60 80 90 Damage mean / 0.1μm 106.48 116.72 118.23 120.21 111.35 108.49 Damage standard deviation 9.52 24.93 16.99 11.67 4.98 3.10 Number of samples / ea 10 10 10 10 10 10

[0069] In the table, ea stands for each, a unit of quantity.

[0070] Please combine Figures 3a to 3e , Figure 6As shown in Table 1, for diamond wire cutting, when the angle between the line mark direction and the dividing line is 0° or 45°, the edge of the transition zone between the outer surface and the damaged area is the most obvious, and the evaluation of the damage depth also has a significant central trend. Considering that when the angle between the line mark direction and the dividing line is 0°, there are only a few or even one line mark as the evaluation interface, which reflects the actual situation of the damage poorly, so 45° can be selected as the angle between the line mark direction and the dividing line. It can be seen from Table 1 that when the angle is 0°, 30°, 45°, 60°, and 90°, the damage standard deviation has a trend of first decreasing and then increasing, and reaches a minimum value at 45°. It can be foreseen that a smaller standard deviation can also be obtained in a small interval of about 45°.

[0071] Please combine Figure 5a to Figure 5e , Figure 7 As shown in Table 2, for mortar line cutting, when the angle between the line mark direction and the dividing line is 90°, the edge of the transition zone between the outer surface and the damaged area is more obvious (slightly worse than 0°), and the central trend of the damage depth evaluation is the most significant. Considering that when the angle between the line mark direction and the dividing line is 90°, there are the most line marks as the evaluation interface, which can truly reflect the damage situation, so 90° can be selected as the angle between the line mark direction and the dividing line. It can be seen from Table 2 that when the angle is 60°, 45°, and 30°, the standard deviation of the damage increases monotonically. It can be foreseen that when the angle is selected as 80-90°, the standard deviation of the damage is very likely to be much smaller than 11.67 at 60°. Therefore, the selection of this angle range is reasonable. In summary, when the evaluation angle of the mortar wire cutting damage depth (i.e., the angle between the line mark direction and the dividing line) is selected as 80-90°, the data standard deviation (i.e., the damage standard deviation) is small, the edge of the transition zone is obvious, and there are enough line marks at the interface as the evaluation interface, which can truly reflect the damage situation.

[0072] In summary, for mortar wire cutting, when the angle between the line mark direction and the dividing line is 90°, the observation result stability is the best. For diamond wire cutting, when the angle between the line mark direction and the dividing line is 45°, the observation result stability is the best. For diamond wire cutting and mortar wire cutting, the corresponding angles (i.e. 45° and 90°) are used to observe the longitudinal damage depth, and the selection requirements of the boundary line between the outer surface and the damaged area and the damage termination line are specified. Compared with other angles, the damage distribution under the high and low efficiency grinding surfaces is uniform, the overall data deviation is small, and there is a significant central trend.

[0073] The above embodiment can accurately measure the damage depth of silicon wafer wire cutting by specifying the angle between the line mark direction and the dividing line. For wire cutting types such as mortar line, structural line, diamond wire, etc., the corresponding line mark angle can be used for measurement to achieve accurate measurement of the damage depth. In addition, different upper boundaries, lower boundaries, and dividing lines can be configured for different wire cutting types, that is, the upper boundary, lower boundary, and dividing line of the diamond wire transition zone are determined according to the position information of the line mark termination point; the upper boundary, lower boundary, and dividing line of the mortar line transition zone are determined according to the position information of the damage point.

[0074] An embodiment of the present application further provides a wire cutting damage depth measurement system for measuring the damage depth of a silicon wafer after wire cutting. The system includes a control module, and the control module is used to execute any of the above methods.

[0075] It should be noted that each embodiment in the present application is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the product embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0076] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0077] It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” or “under” another element, it can be “directly on” or “under” the other element or intervening elements may be present.

[0078] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0079] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A method for measuring the damage depth of wire cutting, characterized in that: For measuring the damage depth of silicon wafers after online cutting, the method comprises: Determine a transition zone between the outer surface of the silicon wafer and the damaged zone; the upper boundary and the lower boundary of the transition zone are parallel to each other, and the upper boundary and the lower boundary are determined according to the line mark direction and the position information of the damage point; Constructing a dividing line parallel to the upper boundary line and bisecting the transition zone; A damage termination line parallel to the boundary line is constructed through the Nth last damage point in the damage area; N is a positive integer; The distance between the boundary line and the damage stop line is measured as the damage depth of the silicon wafer.

2. The method for measuring the wire cutting damage depth according to claim 1, characterized in that: The wire cutting is diamond wire cutting; The upper boundary of the transition zone passes through the first line mark termination point in the transition zone and forms a first target angle with the line mark direction; The lower boundary of the transition zone passes through the target line mark termination point in the transition zone and is parallel to the upper boundary; the target line mark termination point is determined according to the position distribution range of the line mark termination point.

3. The method for measuring the wire cutting damage depth according to claim 2, characterized in that: The first target angle has a value range of 35 degrees to 55 degrees.

4. The method for measuring the wire cutting damage depth according to claim 2, characterized in that: The ratio of the number of line mark termination points in the transition zone to the total number of line mark termination points is a first target ratio; The first target ratio has a value range of 70% to 90%.

5. The method for measuring the wire cutting damage depth according to claim 1, characterized in that: The wire cutting is mortar wire cutting or structural wire cutting; The upper boundary of the transition zone passes through the first damage point in the transition zone and forms a second target angle with the line mark direction; The lower boundary of the transition zone passes through the target damage point in the transition zone and is parallel to the upper boundary; the target damage point is determined according to the position distribution range of the damage point.

6. The method for measuring the wire cutting damage depth according to claim 5, characterized in that: The second target angle has a value range of 80 degrees to 90 degrees.

7. The method for measuring the wire cutting damage depth according to claim 5, characterized in that: The ratio of the number of damage points in the transition zone to the total number of damage points is a second target ratio; The second target ratio ranges from 70% to 90%.

8. A system for measuring the damage depth of wire cutting, characterized in that: Used to measure the damage depth of silicon wafers after online cutting, the system includes a control module, and the control module is used to execute any one of claims 1 to 7.

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