Method and system for measuring wire saw damage depth

Abstract

The application provides a method and system for measuring the damage depth of a silicon wafer after wire sawing, which comprises: determining the 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 wire mark direction and the position information of the damage point; constructing a boundary line parallel to the upper boundary line and bisecting the transition zone; constructing a damage termination line parallel to the boundary line through the Nth damage point in the damage zone; and measuring the distance between the boundary line and the damage termination line as the damage depth of the silicon wafer. By defining the transition zone and the standards of the boundary line and the damage termination line, the application improves the boundary ambiguity and data error problems in the damage depth measurement, improves the measurement accuracy and repeatability, reduces the measurement instability caused by accidental errors, and is suitable for a wide range of types.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicon wafer surface detection, and particularly relates to a wire saw damage depth measurement method and system. BACKGROUND

[0002] In the field of semiconductor manufacturing, the quality of a silicon wafer directly affects subsequent chip manufacturing processes and the performance of the final product. In a wire saw process, such as using a diamond wire, a slurry wire, or the like to cut a silicon wafer. Although these wire saw technologies have the advantages of high efficiency and high processing precision, damage to the surface of the silicon wafer occurs during the cutting process. These damages affect the performance of the silicon wafer, and thus affect the reliability and service life of the entire semiconductor device. Therefore, it is necessary to quantitatively measure the damage depth of the wire saw. Related wire saw evaluation methods mostly focus on the morphology, although the damage depth is also involved, but the data deviation is large due to the unclear evaluation specification, the main reasons are as follows: it is difficult to determine the intersection line between the outer surface and the damage area; there is no uniform standard for determining the damage termination line; researchers ignore the importance of the wire mark direction.

[0003] Based on this, the present application provides a wire saw damage depth measurement method and system to improve related technologies. SUMMARY

[0004] The purpose of the present application is to provide a wire saw damage depth measurement method and system to accurately measure the damage depth of a silicon wafer after wire sawing.

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

[0006] In a first aspect, the present application provides a wire saw damage depth measurement method for measuring the damage depth of a silicon wafer after wire sawing, the method comprising: determining a transition zone between the outer surface of the silicon wafer and a damage area; 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 wire mark direction and the position information of the damage point; constructing a boundary line parallel to the upper boundary line and bisecting the transition zone; constructing a damage termination line parallel to the boundary line through the Nth damage point in the damage area; N is a positive integer; measuring the distance between the boundary line and the damage termination line as the damage depth of the silicon wafer.

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

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

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

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

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

[0012] In some embodiments, a ratio of the number of the damage points in the transition zone to the total number of the 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 system for measuring the damage depth of a wire-cutting, which is used for measuring the damage depth of a silicon wafer after wire cutting, and the system comprises a control module, which is used for executing any of the above methods.

[0014] The application provides a method and system for measuring wire saw damage depth, which establishes a transition zone between the outer surface of a silicon wafer and the damage zone, and constructs a boundary line and a damage termination line in the transition zone to accurately measure the damage depth. Specifically, the method first determines the upper boundary line and the lower boundary line of the transition zone according to the wire mark direction and the position information of the damage point. Then, the boundary line parallel to the upper boundary line and bisecting the transition zone is constructed to accurately divide the outer surface of the silicon wafer and the damage zone. By observing the position of the Nth damage point in the damage zone, the damage termination line parallel to the boundary line is constructed to ensure the stability of the measurement of the damage depth. Next, by measuring the distance between the boundary line and the damage termination line, the damage depth of the silicon wafer is obtained, thereby realizing the quantitative analysis of the wire saw damage depth of the silicon wafer. The application defines the transition zone, the boundary line and the damage termination line, and improves the boundary ambiguity and data error problems in the damage depth measurement. Secondly, the wire mark direction information is fully utilized, so that the damage distribution in the transition zone is more uniform, the data deviation is significantly reduced, and the measurement accuracy and repeatability are improved. In addition, according to the needs of practical application, the Nth damage point is selected as the termination point, which effectively reduces the measurement instability caused by accidental error, and is suitable for damage depth measurement in different types of wire saw process. The application provides an efficient and stable damage depth measurement scheme, which is convenient for reasonably evaluating the wire saw damage depth of the silicon wafer, and is helpful for quality control of silicon wafer processing. BRIEF DESCRIPTION OF DRAWINGS

[0015] The application will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0016] Figure 1 FIG. 1 is a flowchart of a method for measuring wire saw damage depth according to an embodiment of the application.

[0017] Figure 2 FIG. 2 is a damage depth diagram of diamond wire sawing according to an embodiment of the application.

[0018] Figure 3a FIG. 3 is a damage depth diagram of diamond wire sawing according to an embodiment of the application (the wire mark direction is 0 degrees to the boundary line).

[0019] Figure 3b FIG. 4 is a damage depth diagram of diamond wire sawing according to an embodiment of the application (the wire mark direction is 30 degrees to the boundary line).

[0020] Figure 3c FIG. 5 is a damage depth diagram of diamond wire sawing according to an embodiment of the application (the wire mark direction is 45 degrees to the boundary line).

[0021] Figure 3d FIG. 6 is a damage depth diagram of diamond wire sawing according to an embodiment of the application (the wire mark direction is 60 degrees to the boundary line).

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

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

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

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

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

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

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

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

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

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0032] In the description of the embodiments of the present application, it should be understood that the terms "first", "second" are used only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can 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 specifically limited.

[0033] The shape, nanotopography and other parameters of the silicon wafer depend on the process conditions of the wire cutting. The increasingly advanced wire cutting processes such as mortar wire, structural wire and diamond wire have become the main processing methods in the silicon wafer forming section, and have significant advantages due to their fast and efficient characteristics. Related wire cutting evaluation methods are mostly focused on the morphology, although the damage depth is also involved, but often the evaluation specification is not clear, resulting in large data deviation, the main reasons are: it is difficult to judge the junction line between the outer surface and the damage area; there is no uniform standard for judging the damage termination line; researchers ignore the importance of the direction of the wire mark.

[0034] The embodiments of the present application will be described below.

[0035] Referring to Figure 1 , Figure 1 is a flowchart of a wire cutting damage depth measurement method provided by an embodiment of the present application.

[0036] The embodiment of the present application provides a wire cutting damage depth measurement method, which is used for measuring the damage depth of a silicon wafer after wire cutting, and the method comprises steps S101-S104.

[0037] Step S101: determining a transition zone of an outer surface of the silicon wafer and a damage area; 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 position information of the wire mark direction and the damage point.

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

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

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

[0041] In the above embodiment, the transition zone between the outer surface and the damage zone is first determined. For example, the transition zone can be defined as the region where the scratch and the damage coexist. The boundary line is the boundary line between the outer surface and the damage zone, which is parallel to the upper boundary line and bisects the transition zone. The boundary line is located at 1 / 2 of the transition zone, and the distance between the boundary line and the upper boundary line is equal to the distance between the boundary 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 damage zone, and the upper boundary line and the lower boundary line can be determined according to the scratch direction and the position information of the damage point.

[0042] After the silicon wafer is cut by the wire, a plurality of damage points will be formed. Some of the damage points are scratch termination points, and some of the damage points are ordinary damage points which are not scratch termination points. That is, the scratch termination points can be regarded as a subset of the damage points. The last damage point (i.e., the damage point farthest from the outer surface) is selected, and the N-1th damage point observed in the damage zone (i.e., the Nth last damage point) is used to construct a straight line passing through the damage point and parallel to the boundary line as a damage termination line. The above embodiment does not limit N, and N can be 2, 3, 4, 5, 10, etc.

[0043] The above embodiment fixes the standard of the boundary line between the outer surface and the damage zone, fixes the standard of the damage termination line, and fixes the scratch direction, so that the high-efficiency and low-efficiency grinding surfaces are uniformly distributed, and the damage depth can be accurately identified.

[0044] Referring to Figure 2 , Figures 3a to 3e , Figure 2 is a damage depth diagram of a diamond wire saw provided by an embodiment of the present application, Figure 3a is a damage depth diagram of a diamond wire saw provided by an embodiment of the present application (the scratch direction is 0 degrees to the boundary line), Figure 3b is a damage depth diagram of a diamond wire saw provided by an embodiment of the present application (the scratch direction is 30 degrees to the boundary line), Figure 3c is a damage depth diagram of a diamond wire saw provided by an embodiment of the present application (the scratch direction is 45 degrees to the boundary line), Figure 3d is a damage depth diagram of a diamond wire saw provided by an embodiment of the present application (the scratch direction is 60 degrees to the boundary line), Figure 3e is a damage depth diagram of a diamond wire saw provided by an embodiment of the present application (the scratch direction is 90 degrees to the boundary line).

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

[0046] In the above embodiments, the upper boundary line is defined by a passing point and a direction, the point being the first line mark end point in the transition zone, i.e. the line mark end point closest to the outer surface. The upper boundary line passes through the first line mark end point in the transition zone, and the direction of the upper boundary line is at the first target angle with the line mark direction. The lower boundary line can also be defined by a passing point and a direction, the point being a target line mark end point in the transition zone, e.g. a line mark end point determined according to the position distribution range of the line mark end points. The lower boundary line passes through the target line mark end point, and is parallel to the upper boundary line.

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

[0048] Diamond wire has its unique properties, i.e. line mark is the main form of damage, and different line mark depths are the main causes of damage. Therefore, it is necessary to regulate the uniform distribution of line mark end points of different depths on the test surface. In order to regulate the uniform distribution of line marks, it is very important to select a suitable test angle (i.e. the first target angle between the upper boundary line and the line mark direction). When the first target angle is about 45°, the transition zone is relatively narrow, and the standard deviation of the readings is the smallest. When the value range of the first target angle is expanded to 35 degrees to 55 degrees, the standard deviations in this value range are all small, and can reflect the true situation.

[0049] In some embodiments, the ratio of the number of line mark end points in the transition zone to the total number of line mark end points can be a first target ratio. The above embodiments do not limit the first target ratio, in some embodiments, the first target ratio can be in the range of 70% to 90%. As an example, the first target ratio can be 70%, 80%, 85%, 90%, etc. From the experience of practical application, 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%, and a suitable transition zone width can be achieved in this value range, so as to accurately evaluate the damage depth.

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

[0051] As Figure 2 shown, taking diamond wire sawing as an example, first, the standard of the demarcation line between the outer surface and the damage area is fixed, specifically, the upper boundary of the transition zone can be determined by 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 the 80% line mark termination point (corresponding to the transition zone containing 80% line mark termination points). Then, the 1 / 2 of the transition zone is selected as the demarcation line between the outer surface and the damage area. Second, the standard of the damage termination line is fixed, specifically, the last damage point is selected, and a straight line passing through the third last damage point and parallel to the demarcation line is constructed as the damage termination line. Since the angle between the line mark direction and the demarcation line (which can be referred to as the line mark angle) is a fixed value, i.e., the first target angle, the high and low efficiency grinding surfaces can be uniformly distributed.

[0052] As Figures 3a to 3e shown, through a large number of tests, the applicant found that the line mark direction of diamond wire sawing has a significant impact on the width of the transition zone. Reasonably selecting the angle between the line mark direction and the demarcation line (i.e., the first target angle) can minimize the width of the transition zone. In a specific application scenario of diamond wire sawing, when the angle between the line mark direction and the demarcation line is 45° (°, degree unit), the transition zone is the shortest, the high and low efficiency grinding surfaces are the most evenly distributed, and the observation results have the best stability.

[0053] The above embodiments consider the following aspects for selecting the corresponding demarcation line of diamond wire sawing. From Figure 2 it can be seen that for the demarcation line between the outer surface and the damage area, since the line mark is not uniform in depth and the surface topography is difficult to determine, a transition zone can be defined, for example, the position of the first line mark termination point and the 80% line mark termination point are specified as the upper boundary and the lower boundary of the transition zone, respectively, both of which are parallel to each other and form a first target angle with the line mark direction. Within this transition zone, it is difficult to distinguish between the outer surface and the damage area, so the 1 / 2 of the transition zone can be selected as the demarcation line between the outer surface and the damage area. For the damage depth termination line (i.e., the damage termination line), in order to reduce accidental errors, the third last damage point in the silicon wafer can be selected as the damage termination point, and a damage termination line can be further defined. For the selection of the angle between the line mark direction and the demarcation line (i.e., the first target angle), a large amount of data can be summarized, and the purpose is to make the distribution of different line marks more uniform, so as to observe the most obvious interface, which is extremely important for damage depth identification, and ensures the accuracy of the data.

[0054] Referring to Figure 4 , Figures 5a to 5e , Figure 4 is a damage depth diagram of mortar wire sawing provided by the embodiments of the present application,Figure 5a is a damage depth map of a mortar line wire cutting (the line mark direction is 0 degrees to the boundary line) provided by an embodiment of the present application, Figure 5b is a damage depth map of a mortar line wire cutting (the line mark direction is 30 degrees to the boundary line) provided by an embodiment of the present application, Figure 5c is a damage depth map of a mortar line wire cutting (the line mark direction is 45 degrees to the boundary line) provided by an embodiment of the present application, Figure 5d is a damage depth map of a mortar line wire cutting (the line mark direction is 60 degrees to the boundary line) provided by an embodiment of the present application, Figure 5e is a damage depth map of a mortar line wire cutting (the line mark direction is 90 degrees to the boundary line) provided by an embodiment of the present application.

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

[0056] In the above embodiments, the upper boundary line is defined by a passing point and a direction, the point being a first damage point in the transition region, i.e., the damage point closest to the outer surface. The upper boundary line passes through the first damage point in the transition region, and the direction of the upper boundary line is at a second target angle to the line mark direction. The lower boundary line can also be defined by a passing point and a direction, the point being a target damage point in the transition region, e.g., a damage point determined according to a position distribution range of damage points. The lower boundary line passes through the target damage point, and is parallel to the upper boundary line.

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

[0058] In practice, the applicant found that when the second target angle between the upper boundary line and the direction of the line mark is 90°, the transition zone edge between the outer surface and the damaged area is more obvious, and the central trend in damage depth evaluation is most significant. Simultaneously, when the second target angle between the upper boundary line and the direction of the line mark is 90°, the interface has the most line marks as an evaluation interface, accurately reflecting the damage situation. In other words, the advantage of a 90° second target angle is that the number of observable line marks is sufficient, reducing random errors in readings caused by small angles and single line marks. Even when the angle is lowered to 80°, the number of line marks remains relatively sufficient, with no small angles, and random errors remain small. Therefore, the range of the second target angle can be extended to 80°–90°, within which random errors can be reduced.

[0059] In some embodiments, the ratio of the number of damage points in the transition zone to the total number of damage points can be a second target ratio. The above embodiments do not limit the second target ratio; in some embodiments, the value of the second target ratio can be between 70% and 90%. For example, the second target ratio can be 70%, 80%, 85%, 90%, etc. Practical experience shows that when the second target ratio is less than 70%, the damage transition zone is too narrow, and the damage depth is too large; when the second target ratio is greater than 90%, the damage transition zone is too wide, and the damage depth is too small. Therefore, setting the value range of the second target ratio to 70% to 90% allows for a suitable transition zone width within this range, thereby accurately evaluating the damage depth.

[0060] like Figure 4 As shown, taking mortar line cutting as an example, firstly, the standard for 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 where the damage point just appears (i.e., 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 the 80% damage point (corresponding to the transition zone containing 80% of the damage points). Then, the halfway point of the transition zone is selected as the boundary line between the outer surface and the damaged area. Secondly, the standard for the damage termination line is fixed. Specifically, the last damage point is selected, and damage points are observed into the damaged area. A straight line passing through the third-to-last damage point and parallel to the boundary line is constructed as the damage termination line. Since the angle between the line mark direction and the boundary line is a fixed value, i.e., the first target angle, the high and low efficiency grinding surfaces can be evenly distributed.

[0061] like Figures 5a to 5eAs shown, the applicant found that the line mark direction of the mortar line wire cutting has a significant impact on the distribution of the grinding surface through a large number of tests. Reasonable selection of the angle between the line mark direction and the boundary line (i.e., the second target angle) can make the alternation of the high-efficiency grinding surface and the low-efficiency grinding surface as small as possible. In a specific application scenario of the mortar line wire cutting, when the angle between the line mark direction and the boundary 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 for the selection of the corresponding boundary line of the mortar line wire cutting. Figure 4 As can be seen from the above, the line mark width of the mortar line is wider than that of the diamond wire, so the selection rule is different from that of the diamond wire cutting. Figure 4 As can be seen from the above, the line mark width of the mortar line is wider than that of the diamond wire, so the selection rule is different from that of the diamond wire cutting.

[0063] Referring to Figure 6 and Figure 7 , Figure 6 is a damage depth box plot of the diamond wire cutting provided by the embodiment of the present application, Figure 7 is a damage depth box plot of the mortar line wire cutting provided by the embodiment of the present application.

[0064] According to the above technical means and rules, the applicant tests the damage depth of the diamond wire cutting and the mortar line wire cutting as follows.

[0065] Table 1 Damage depth comparison table of different line mark angles of diamond wire

[0066] Scratch angle / ° 0 30 35 45 55 60 90 Damage average / 0.1 μm 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 Damage depth comparison table of different line mark angles of mortar line

[0068] Scratch angle / ° 0 30 45 60 80 90 Damage average / 0.1 μm 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 is each, a quantity unit.

[0070] Please refer to Figures 3a to 3e , Figure 6and Table 1, for the diamond wire line cutting, when the included angle between the wire mark direction and the boundary line is 0° or 45°, the transition zone edge of the outer surface and the damage area is most obvious, and the evaluation of the damage depth also has a significant central tendency. Considering that when the included angle between the wire mark direction and the boundary line is 0°, only a few or even one wire mark is used as the evaluation interface, which is poor in reflecting the actual damage, therefore, 45° can be selected as the included angle between the wire mark direction and the boundary line. As can be seen from Table 1, when the included angle is 0°, 30°, 45°, 60°, 90°, the damage standard deviation has a change trend of first decreasing and then increasing, and the minimum value is obtained at 45°. It can be predicted that a smaller standard deviation can also be obtained within a small interval of about 45°.

[0071] Please refer to Figures 5a to 5e , Figure 7 and Table 2, for the mortar wire line cutting, when the included angle between the wire mark direction and the boundary line is 90°, the transition zone edge of the outer surface and the damage area is relatively obvious (slightly worse than 0°), and the central tendency of the damage depth evaluation is most significant. Considering that when the included angle between the wire mark direction and the boundary line is 90°, the most wire marks are used as the evaluation interface, which can truly reflect the damage condition, therefore, 90° can be selected as the included angle between the wire mark direction and the boundary line. As can be seen from Table 2, when the included angle is 60°, 45°, 30°, the damage standard deviation is monotonously increasing, and it can be predicted that when the included angle is selected as 80-90°, the damage standard deviation is extremely likely to be much smaller than 11.67 at 60°. Therefore, the selection of the angle range is reasonable. In summary, when the evaluation angle (i.e., the included angle between the wire mark direction and the boundary line) of the damage depth of the mortar wire line cutting is selected as 80-90°, the data standard deviation (i.e., the damage standard deviation) is smaller, the transition zone edge is obvious, and the interface has enough wire marks as the evaluation interface, which can truly reflect the damage condition.

[0072] In summary, for the mortar wire line cutting, when the included angle between the wire mark direction and the boundary line is 90°, the stability of the observation result is the best. For the diamond wire line cutting, when the included angle between the wire mark direction and the boundary line is 45°, the stability of the observation result is the best. For the diamond wire line cutting and the mortar wire line cutting, the longitudinal damage depth is observed by using the above-mentioned corresponding angles (i.e., 45° and 90°) respectively, and the selection requirements of the intersection line of the outer surface and the damage area and the termination line of the damage are specified. Compared with other angles, the damage distribution of the high and low efficient grinding surfaces at this time is uniform, the overall data deviation is small, and there is a significant central tendency.

[0073] The above embodiment can accurately measure the damage depth of the wire sawing of the silicon wafer by defining the included angle between the wire mark direction and the boundary line. For the wire sawing types such as mortar wire, structure wire, and diamond wire, the corresponding wire mark angle can be used for measurement to realize accurate measurement of the damage depth. In addition, different upper limit lines, lower limit lines, and boundary lines can be configured for different wire sawing types, that is, the upper limit line, the lower limit line, and the boundary line of the diamond wire transition zone are determined according to the position information of the wire mark end point; the upper limit line, the lower limit line, and the boundary line of the mortar wire transition zone are determined according to the position information of the damage point.

[0074] The embodiments of the present application also provide a wire sawing damage depth measurement system for measuring the damage depth of a silicon wafer after wire sawing, the system comprising a control module configured to execute any of the above methods.

[0075] It should be noted that each of the embodiments 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. Each embodiment focuses on the difference from other embodiments. In particular, for the product embodiments, since they are basically similar to the method embodiments, they are described more simply, and the relevant parts can be referred to the part of the method embodiments.

[0076] Unless otherwise defined, technical terms or scientific terms used in the present disclosure shall have the ordinary meaning understood by a person of ordinary skill in the art to which the present disclosure pertains. The terms "first", "second", and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are used to distinguish different components. The terms "include" or "contain" and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", and the like are used to represent relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships may also change accordingly.

[0077] It can be understood that when an element such as a layer, a film, a region, or a substrate is referred to as being "on" or "under" another element, the element can be "directly" on or under the other element, or there can be an intermediate element.

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

[0079] The above merely provides the specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present disclosure, which should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A method of measuring wire cut lesion depth, characterized by, A method for measuring damage depth of a silicon wafer after in-line cutting, the method comprising: determining a transition zone between an outer surface of the silicon wafer and a damage zone; an upper boundary line and a 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 a line mark direction and position information of damage points; constructing a boundary line parallel to the upper boundary line and bisecting the transition zone; constructing a damage termination line parallel to the boundary line through an Nth damage point in the damage zone; N is a positive integer; measuring a distance between the boundary line and the damage termination line as the damage depth of the silicon wafer; wherein the in-line cutting is a diamond wire in-line cutting; the upper boundary line of the transition zone passes through a first line mark termination point in the transition zone and forms a first target angle with the line mark direction; the lower boundary line of the transition zone passes through a target line mark termination point in the transition zone and is parallel to the upper boundary line; the target line mark termination point is determined according to a position distribution range of line mark termination points.

2. The wire cutting damage depth measurement method according to claim 1, wherein, the first target angle is in a range of 35 degrees to 55 degrees.

3. The wire cutting damage depth measurement method according to claim 1, wherein, a ratio of a number of line mark termination points in the transition zone to a total number of line mark termination points is a first target ratio; the first target ratio is in a range of 70% to 90%.

4. A method of measuring the depth of a wire saw damage, characterized by, A method for measuring damage depth of a silicon wafer after in-line cutting, the method comprising: determining a transition zone between an outer surface of the silicon wafer and a damage zone; an upper boundary line and a 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 a line mark direction and position information of damage points; constructing a boundary line parallel to the upper boundary line and bisecting the transition zone; constructing a damage termination line parallel to the boundary line through an Nth damage point in the damage zone; N is a positive integer; measuring a distance between the boundary line and the damage termination line as the damage depth of the silicon wafer; wherein the in-line cutting is a mortar wire in-line cutting or a structure wire in-line cutting; the upper boundary line of the transition zone passes through a first damage point in the transition zone and forms a second target angle with the line mark direction; the lower boundary line of the transition zone passes through a target damage point in the transition zone and is parallel to the upper boundary line; the target damage point is determined according to a position distribution range of damage points.

5. The wire cutting lesion depth measurement method according to claim 4, wherein, the second target angle is in a range of 80 degrees to 90 degrees.

6. The wire cutting lesion depth measurement method according to claim 4, wherein, a ratio of a number of damage points in the transition zone to a total number of damage points is a second target ratio; the second target ratio is in a range of 70% to 90%.

7. A wire cutting lesion depth measurement system characterized by, A system for measuring damage depth of a silicon wafer after in-line cutting, the system comprising a control module configured to perform the method of any one of claims 1 to 6.

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