Pre-alignment method, system, wafer edge trimmer, data processing device and medium

Abstract

Embodiments of the present specification provide a pre-alignment method, system, wafer edge trimming machine, data processing device and medium, wherein the pre-alignment method comprises: obtaining edge data of each measurement point of a wafer, and a plurality of height data of each measurement point relative to a preset reference, wherein the height data is used to represent the warping degree of the wafer surface; correcting the edge data of each measurement point according to the plurality of height data of each measurement point relative to the preset reference, to determine the corrected edge data of each measurement point; and generating a position adjustment signal according to the corrected edge data of each measurement point and a pre-alignment position, wherein the position adjustment signal is used to control the adjustment of the position of the wafer. By using the above technical solution, the alignment accuracy of the wafer can be improved.

Description

Technical Field

[0001] The embodiments in this specification relate to the field of wafer manufacturing technology, and in particular to a pre-alignment method, system, wafer edge-checking machine, data processing equipment, and medium. Background Technology

[0002] In the semiconductor manufacturing process, the position and orientation of the wafer are uncertain when it is placed in the wafer transfer box. Therefore, the wafer needs to be pre-aligned before it is transferred to the corresponding processing machine through the wafer transfer box.

[0003] Against this backdrop, how to improve the accuracy of wafer pre-alignment has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, embodiments of this specification provide a pre-alignment method, system, wafer edge-checking machine, data processing equipment, and medium that can improve wafer alignment accuracy.

[0005] First, this specification provides a pre-alignment method, including:

[0006] The edge data of each measurement point on the wafer and multiple height data of each measurement point relative to a preset reference are acquired. The height data is used to characterize the degree of warpage of the wafer surface.

[0007] Based on multiple height data of each measurement point relative to a preset benchmark, the edge data of each measurement point is corrected, and the corrected edge data of each measurement point is determined.

[0008] Based on the corrected edge data and pre-alignment position of each measurement point, a position adjustment signal is generated, which is used to control and adjust the position of the wafer.

[0009] Optionally, the height data is the height of the connection point of each straight line segment relative to the preset reference, and the straight line segments are used to fit the warpage of the wafer surface.

[0010] Optionally, the step of correcting the edge data of each measurement point based on multiple height data of each measurement point relative to a preset reference, and determining the corrected edge data of each measurement point, includes:

[0011] Based on multiple height data at each measurement point and the theoretical diameter of the wafer, the correction value corresponding to the edge data at each measurement point is determined;

[0012] Based on the correction value corresponding to the edge data of each measurement point, the edge data of the corresponding measurement point is corrected to obtain the corrected edge data of each measurement point.

[0013] Optionally, there are multiple straight line segments, which are distributed on both sides of the plane where the preset rotation center is located, and the connection points of the straight line segments on the same side are connected in sequence.

[0014] The step of determining the correction value corresponding to the edge data of each measurement point based on multiple height data of each measurement point and the theoretical diameter of the wafer includes:

[0015] Based on multiple height data points, determine the length of any one of the multiple line segments;

[0016] The compensation value of the measurement point is determined based on the length of each straight segment at the measurement point and the theoretical diameter of the wafer.

[0017] Based on the compensation value corresponding to the measurement point, the length of the straight line segment on one side of the measurement point, and the maximum distance from the rotation center along the wafer radial direction among multiple connection points on the same side of the measurement point, the correction value corresponding to the edge data of the measurement point is determined.

[0018] Optionally, determining the length value of any one of the multiple line segments based on multiple height data of the measurement points includes:

[0019] For any straight line segment on any side, along the radial direction of the wafer, the length of the straight line segment is determined based on the distance between the first connection point and the second connection point of the straight line segment, and the height difference between the second connection point and the first connection point relative to the preset reference. The first connection point of the straight line segment closest to the rotation center coincides with the rotation center.

[0020] Optionally, along the radial direction of the wafer, the distance between the first connection point and the second connection point of each straight line segment is the same, and the maximum distance between the multiple connection points and the rotation center is less than the theoretical diameter of the wafer.

[0021] Optionally, determining the compensation value of the measurement point based on the length of each straight segment of the measurement point and the theoretical diameter of the wafer includes:

[0022] Determine the sum of the lengths of all line segments;

[0023] The difference between the theoretical diameter of the wafer and the sum of the lengths of each straight line segment is determined, and half of the difference is used as the compensation value for the corresponding measurement point.

[0024] Optionally, determining the correction value corresponding to the edge data of the measurement point based on the compensation value corresponding to the measurement point, the length of the straight line segment on one side of the measurement point, and the maximum distance from the rotation center along the wafer radial direction among multiple connection points on the same side of the measurement point includes:

[0025] Determine the sum of the lengths of all straight line segments on the same side of the measurement point, and use this sum as the first total length value;

[0026] The sum of the compensation value corresponding to the measurement point and the first total length value is determined as the second total length value;

[0027] The difference between the second total length value and the maximum distance value from the rotation center among multiple connection points on the same side is determined as the correction value corresponding to the edge data of the measurement point.

[0028] Optionally, the step of correcting the edge data of the corresponding measurement points based on the correction values ​​corresponding to the edge data of each measurement point to obtain the corrected edge data of each measurement point includes:

[0029] The sum of the correction value corresponding to the edge data of the measurement point and the edge data is used as the correction edge data of the corresponding measurement point.

[0030] Optionally, before accumulating the correction value corresponding to the edge data of the measurement point with the edge data, the method further includes:

[0031] Based on the number of measurement points, the preset included angle value, and the rotation angle value of the wafer, the edge data of the measurement points are aligned with their corresponding correction values.

[0032] Optionally, the step of generating a position adjustment signal based on the corrected edge data and pre-alignment position of each measurement point, wherein the position adjustment signal is used to control the adjustment of the wafer's position, includes:

[0033] Convert the corrected edge data of each measurement point into the corresponding coordinate values;

[0034] Based on the coordinate values ​​of each measurement point, determine the center coordinate value of the wafer and the alignment angle of the wafer relative to the pre-alignment position;

[0035] The position adjustment signal is generated based on the center coordinates of the wafer, the alignment angle, and the pre-alignment position to adjust the position of the wafer.

[0036] Optionally, determining the center coordinates of the wafer based on the coordinates of each measurement point includes:

[0037] A preset fitting algorithm is used to fit the coordinate values ​​of each measurement point to obtain the fitting circle corresponding to the wafer, and the center coordinate value of the fitting circle is determined as the center coordinate value of the wafer.

[0038] Optionally, before the step of using a preset fitting algorithm to fit the coordinate values ​​of each measurement point to obtain the fitted circle corresponding to the wafer, the method further includes:

[0039] Remove the coordinate values ​​of feature points from the measurement points.

[0040] Optionally, the feature point is located at the tangent edge of the wafer;

[0041] Determining the alignment angle of the wafer relative to the pre-alignment position based on the coordinate values ​​of each measurement point includes:

[0042] Based on the coordinate values ​​of the feature points, the slope of the straight line corresponding to the cut edge is determined, and the angle value corresponding to the slope is used as the alignment angle of the wafer.

[0043] Optionally, the feature point is located at a notch in the wafer;

[0044] Determining the alignment angle of the wafer relative to the pre-alignment position based on the coordinate values ​​of each measurement point includes:

[0045] Based on the coordinates of the feature point at the lowest point in the notch and the coordinates of the center of the wafer, the slope of the straight line formed by the feature point at the lowest point and the center of the wafer is determined, and the angle value corresponding to the slope is used as the alignment angle of the wafer.

[0046] Optionally, generating the position adjustment signal based on the wafer's center coordinates, the alignment angle, and the pre-alignment position includes:

[0047] The center offset value of the wafer is determined based on the center coordinates of the wafer and the pre-alignment position.

[0048] The position adjustment signal is generated based on the alignment angle and the center offset value of the wafer.

[0049] Accordingly, embodiments of this specification also provide a pre-alignment system, characterized in that it includes:

[0050] The control module is adapted to generate motion control signals; and is adapted to correct the edge data of each measurement point of the wafer based on multiple height data of each measurement point of the wafer relative to a preset reference, determine the corrected edge data of each measurement point, and generate a position adjustment signal based on the corrected edge data of each measurement point and a pre-alignment position, wherein the position adjustment signal is used to control and adjust the position of the wafer; wherein the height data is used to characterize the degree of warpage of the wafer surface.

[0051] The carrier module is adapted to carry and drive the wafer to move in response to the motion control signal;

[0052] The data acquisition module is suitable for acquiring edge data of each measurement point on the wafer, as well as acquiring multiple height data of each measurement point relative to a preset reference.

[0053] Optionally, the data acquisition module includes:

[0054] The first data acquisition unit is located on opposite sides of the wafer and is suitable for acquiring edge data of each measurement point on the wafer.

[0055] The second data acquisition unit is located above the wafer and is suitable for acquiring multiple height data of each measurement point on the wafer relative to a preset reference.

[0056] Optionally, the second data acquisition unit includes multiple sub-data acquisition units, each sub-data acquisition unit is arranged radially along the wafer and distributed on both sides of the plane where the rotation center of the carrier module is located. For the sub-data acquisition units distributed on one side of the measurement point, the distance between the sub-data acquisition unit closest to the plane where the rotation center is located and the rotation center is a first distance, and the distance between each sub-data acquisition unit is a second distance, and the first distance and the second distance are the same.

[0057] This specification also provides a wafer edge-tracing machine, including the pre-alignment system described in any of the foregoing embodiments.

[0058] This specification also provides a data processing device, including a memory and a processor, wherein the memory is adapted to store one or more computer instructions, and the processor, when executing the computer instructions, performs the pre-alignment method described in any of the foregoing embodiments.

[0059] This specification also provides a computer-readable storage medium storing computer instructions, which, when executed, perform the pre-alignment method described in any of the foregoing embodiments.

[0060] The pre-alignment method described in this specification corrects the edge data of each measurement point based on multiple height data points relative to a preset reference. Since the height data can characterize the degree of warpage of the wafer surface, the influence of wafer surface warpage on the edge data of each measurement point can be eliminated, improving the accuracy of the obtained corrected edge data. Furthermore, based on the corrected edge data of each measurement point and the pre-alignment position, the accuracy of the generated position adjustment signal can be improved. Since the position adjustment signal can be used to control and adjust the position of the wafer, the alignment accuracy of the wafer can be improved.

[0061] Furthermore, the wafer surface exhibits a curved warp. By fitting the wafer surface warp with straight line segments, the computational complexity can be reduced, and by using the height of the connection points of each straight line segment relative to the preset reference as height data, the accuracy of the height data can be improved.

[0062] Furthermore, since the theoretical diameter of the wafer is a fixed value, the correction values ​​corresponding to the edge data of each measurement point obtained based on multiple height data of each measurement point and the theoretical diameter of the wafer can more accurately reflect the degree of influence of wafer surface warping on the theoretical diameter of the wafer. In addition, by correcting the edge data of the corresponding measurement point based on the correction values ​​corresponding to the edge data of each measurement point, the accuracy of obtaining the corrected edge data of each measurement point can be improved.

[0063] Furthermore, by making the distance between the first connection point and the second connection point of each straight line segment the same along the radial direction of the wafer, the computational complexity can be reduced and the computational efficiency improved. Moreover, by making the maximum distance between the multiple connection points and the rotation center less than the theoretical diameter of the wafer, the height data of each measurement point on the circumference of the wafer relative to a preset reference can be obtained.

[0064] Furthermore, before accumulating the correction value corresponding to the edge data of the measurement point with the edge data, the edge data of the measurement point can be aligned with its corresponding correction value based on the number of measurement points, the preset included angle value, and the rotation angle value of the wafer, thereby improving the correspondence between the edge data of the measurement point and its corresponding correction value, and thus improving the accuracy of the corrected edge data.

[0065] Furthermore, by converting the correction data of each measurement point into corresponding coordinate values, the center coordinates of the wafer and the alignment angle of the wafer relative to the pre-alignment position can be determined based on the coordinates of each measurement point. Then, based on the center coordinates of the wafer, the alignment angle, and the pre-alignment position, the position of the wafer can be adjusted to align the wafer center with the pre-alignment position. The implementation method is simple.

[0066] Furthermore, by employing a preset fitting algorithm, the coordinate values ​​of each measurement point are fitted to obtain a fitted circle that reflects the wafer's morphology. Consequently, the determined center coordinates of the wafer can more accurately reflect the actual coordinates of the wafer's center, further improving alignment accuracy.

[0067] Furthermore, since the coordinate values ​​of the feature points vary significantly relative to the coordinate values ​​of other measurement points, by eliminating the coordinate values ​​of the feature points among the measurement points, a more accurate fitted circle can be obtained, further improving the alignment accuracy. Attached Figure Description

[0068] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this specification. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0069] Figure 1 A schematic diagram of a pre-alignment system is shown.

[0070] Figure 2 A flowchart of a pre-alignment method according to an embodiment of this specification is shown;

[0071] Figure 3 A flowchart of a method for determining corrected edge data for each measurement point is shown in an embodiment of this specification;

[0072] Figure 4 A flowchart of a method for adjusting wafer position is shown in an embodiment of this specification;

[0073] Figure 5 This diagram illustrates the change in edge data of a measurement point in an embodiment of this specification.

[0074] Figure 6a A schematic diagram of a wafer with a truncated edge is shown;

[0075] Figure 6b A schematic diagram of a wafer with a notch is shown;

[0076] Figure 7 A flowchart of a pre-alignment method in a specific application scenario of an embodiment of this specification is shown;

[0077] Figure 8 A schematic diagram illustrating a method for determining the length of a straight line segment is shown in an embodiment of this specification.

[0078] Figure 9 A schematic diagram of a pre-alignment system according to an embodiment of this specification is shown;

[0079] Figure 10 This diagram shows a top view illustrating the distribution of modules in a pre-alignment system according to an embodiment of this specification.

[0080] Figure 11 A schematic diagram showing the relative distribution positions of a multi-sub-data acquisition unit in an embodiment of this specification is shown;

[0081] Figure 12 A structural block diagram of a data processing device according to an embodiment of this specification is shown. Detailed Implementation

[0082] To enable those skilled in the art to better understand the shortcomings of existing wafer pre-alignment schemes, the following detailed explanation is provided through specific examples.

[0083] Reference Figure 1 The diagram shown is a structural schematic of a pre-alignment system, as follows: Figure 1 As shown, the pre-alignment system includes: displacement sensor 1, controller ( Figure 1 (Not marked), stepper driver ( Figure 1 (Not shown), stepper motor 2 and turntable 3, wherein the stepper driver receives the control signal from the controller and can drive the stepper motor 2 to move, and drive the turntable 3 to move. Since the wafer 4 is placed on the turntable 3, the wafer 4 can rotate together with the turntable 3.

[0084] The controller can acquire displacement data obtained by the displacement sensor 1 sampling the circumference of the wafer 4. Based on the displacement data, it can determine the wafer's center offset and the deflection angle of the center relative to the pre-aligned position. Based on the deflection angle and the center offset, it can adjust the position of the wafer.

[0085] In actual manufacturing, the wafer surface is subjected to asymmetrical stress, which causes asymmetrical warping of the wafer surface, resulting in a shift in the wafer's center and making it impossible to achieve wafer pre-alignment.

[0086] For warped wafers, to reduce the impact of wafer warping on pre-alignment accuracy, in embodiments of this specification, edge data at each measurement point can be corrected based on multiple height data points relative to a preset reference. Since height data can characterize the degree of wafer surface warping, the influence of wafer surface warping on the edge data at each measurement point can be eliminated, improving the accuracy of the obtained corrected edge data. Furthermore, based on the corrected edge data at each measurement point and the pre-alignment position, the accuracy of the generated position adjustment signal can be improved. Since the position adjustment signal can be used to control and adjust the wafer's position, the wafer alignment accuracy can be improved.

[0087] To enable those skilled in the art to better understand the inventive concept, working principle and advantages of the embodiments of this specification, the pre-alignment scheme in the embodiments of this specification is described in detail below.

[0088] Reference Figure 1 The flowchart shown in this specification illustrates a pre-alignment method in an embodiment of this specification. In some embodiments of this specification, the wafer can be pre-aligned according to the following steps:

[0089] S11, acquire edge data of each measurement point on the wafer.

[0090] Specifically, edge data of each measurement point on the wafer can be acquired during the wafer's rotation.

[0091] In some embodiments of this specification, the measurement points can be distributed on the circumference of the wafer, and the obtained edge data can be the distance between the circumference of the wafer and the rotation center point.

[0092] In a specific embodiment, the wafer can be placed on a stage, and the stage drives the wafer to rotate. In this case, the center of rotation can be the center of the stage plane.

[0093] S12, acquire multiple height data of each measurement point on the wafer relative to a preset reference.

[0094] Among them, height data is used to characterize the degree of warpage on the wafer surface.

[0095] Specifically, when there is warping on the wafer surface, the height data of each measurement point on the wafer surface relative to the preset reference are not exactly the same. The greater the degree of warping on the wafer surface, the greater the difference in the height data of each measurement point relative to the preset reference. Therefore, multiple height data of each measurement point on the wafer relative to the preset reference can be obtained to assess the degree of warping on the wafer surface.

[0096] In some embodiments, the preset reference may be a stage plane. In other embodiments, the preset reference may also be the bottom surface of the wafer (the side corresponding to the wafer surface).

[0097] S13, Based on multiple height data of each measurement point relative to the preset benchmark, correct the edge data of each measurement point and determine the corrected edge data of each measurement point.

[0098] Specifically, since height data can be used to characterize the degree of warping on the wafer surface, the influence of wafer surface warping on the edge data of each measurement point can be eliminated by correcting the edge data of each measurement point, thereby improving the accuracy of the corrected edge data.

[0099] S14, Based on the corrected edge data and pre-alignment position of each measurement point, a position adjustment signal is generated, which is used to control and adjust the position of the wafer.

[0100] Specifically, based on the corrected edge data of each measurement point, the current position of the wafer can be determined, and then, in conjunction with the pre-alignment position, a position adjustment signal can be generated. In response to the position adjustment signal, the position of the wafer can be adjusted so that the position of the wafer is aligned with the pre-alignment position.

[0101] Therefore, by using the pre-alignment method in the embodiments of this specification, the accuracy of the final generated position adjustment signal can be improved by correcting the edge data of each measurement point. Since the position adjustment signal can be used to control and adjust the position of the wafer, the alignment accuracy of the wafer can be improved.

[0102] It should be noted that there is no necessary order between some steps in the above embodiments. They can be executed simultaneously or sequentially as long as no contradictions are caused. For example, steps S11 and S12 can be executed before step S13.

[0103] In practice, due to factors such as temperature, when the coefficient of thermal expansion of the wafer and the thin film material are different, the wafer surface will exhibit different forms of warping. For example, when the coefficient of thermal expansion of the wafer is less than that of the thin film material, the wafer surface will exhibit concave warping; conversely, when the coefficient of thermal expansion of the wafer is greater than that of the thin film material, the wafer surface will exhibit convex warping.

[0104] Whether the warping is concave or convex, the wafer surface exists as a curve, and the parameters of the curve (e.g., length, slope, etc.) are difficult to determine. Therefore, in some embodiments of this specification, the warping of the wafer surface can be segmented and fitted with straight line segments.

[0105] In this case, the obtained height data can be the height of the connection point of each straight line segment relative to the preset reference, and the straight line segment can be used to fit the warping of the wafer surface.

[0106] Therefore, by using straight line segments to fit the warping of the wafer surface, the computational complexity can be reduced, and the height of the connection point of each straight line segment relative to the preset reference can be used as the height data, thereby improving the accuracy of the height data.

[0107] In practical implementation, various methods can be used to convert a warped curve into a straight line segment. For example, the least squares method can be used to convert the warped curve into a straight line segment. It should be noted that how to convert a warped curve into a straight line segment is not the focus of this invention and will not be described in detail here.

[0108] In the actual pre-alignment process, the warp curve of the wafer surface can be obtained in advance, and then the warp curve can be converted into multiple straight line segments and the information of each straight line segment can be stored.

[0109] In practice, once the height of each straight line segment and the connection point of each straight line segment relative to the preset benchmark is determined, the correction value corresponding to the edge data of each measurement point can be obtained, thereby correcting the edge data of each measurement point.

[0110] See Figure 3 The flowchart shown in this specification illustrates a method for determining corrected edge data for each measurement point in an embodiment of this specification. In some embodiments of this specification, such as... Figure 3 As shown, the corrected edge data for each measurement point can be determined in the following manner:

[0111] S131, based on multiple height data of each measurement point and the theoretical diameter of the wafer, determine the correction value corresponding to the edge data of each measurement point.

[0112] Specifically, the height data is generated by the warping of the wafer surface and varies with the degree of warping. The theoretical diameter of the wafer is a fixed value (for example, the diameter of an 8-inch wafer is 200mm). Therefore, based on the multiple height data of each measurement point and the theoretical diameter of the wafer, the correction value corresponding to the edge data of each measurement point can more accurately reflect the degree of influence of wafer surface warping on the theoretical diameter of the wafer.

[0113] In practice, the theoretical diameter of the wafer is measured along the wafer's radial direction, while the height data is measured perpendicular to the wafer's radial direction. That is, the two are data in different dimensions. Therefore, the height data can be converted to obtain data in the same dimension as the theoretical diameter of the wafer.

[0114] In specific implementation, in order to fit the warp curve more accurately, the warp curve can be divided into multiple segments, and multiple straight line segments can be used to fit the warp curve. Therefore, there can be multiple straight line segments in the embodiments of this specification, and the wafer is randomly placed on the stage. When using straight line segments to fit the warp of the wafer surface, the multiple straight line segments can be distributed on both sides of the plane where the preset rotation center is located.

[0115] In some embodiments of this specification, the connection points of the line segments located on the same side of the plane where the center of rotation is located can be connected sequentially.

[0116] Accordingly, as a specific example, the correction value corresponding to the edge data of each measurement point can be determined in the following way:

[0117] 1) Based on the height data of multiple measurement points, determine the length of any one of the multiple straight line segments.

[0118] Specifically, since the height data is the height of the connection point of each straight line segment relative to the preset benchmark, the length value of any one of the multiple straight line segments can be determined based on the multiple height data of the measurement points and the location of each connection point.

[0119] For example, for any straight line segment on any side, along the radial direction of the wafer, the length of the straight line segment can be determined based on the distance between the first connection point and the second connection point of the straight line segment, and the height difference between the second connection point and the first connection point relative to the preset reference, wherein the first connection point of the straight line segment closest to the rotation center coincides with the rotation center.

[0120] That is, based on the distance between the first and second connection points of the straight line segment, the length of the straight line segment in the radial direction of the wafer can be determined. Then, based on the height difference of the straight line segment in the direction perpendicular to the radial direction of the wafer, the length of the straight line segment can be determined by using the Pythagorean theorem.

[0121] In practice, for line segments located on the same side of the plane where the center of rotation is located, the second connection point of one of the adjacent line segments is connected to the first connection point of the other line segment.

[0122] In some embodiments of this specification, in order to reduce computational complexity and improve computational efficiency, the distance between the first connection point and the second connection point of each straight line segment along the radial direction of the wafer can be the same, and the maximum distance between the multiple connection points and the rotation center is less than the theoretical diameter of the wafer, so as to obtain the height data of each measurement point on the circumference of the wafer relative to the preset reference.

[0123] It is understood that the distance between the first connection point and the second connection point of each straight line segment may also be different. This specification does not impose any restrictions on this, as long as the distance between the first connection point and the second connection point along the wafer radial direction can be determined.

[0124] 2) Determine the compensation value of the measurement point based on the length of each straight segment of the measurement point and the theoretical diameter of the wafer.

[0125] Specifically, the length of each straight line segment can represent the length of each warp curve on the wafer surface, which can characterize the actual diameter of the wafer. Since the theoretical diameter of the wafer is fixed, the influence of warping on the theoretical diameter of the wafer can be determined based on the length of each straight line segment and the theoretical diameter of the wafer.

[0126] As an alternative example, the sum of the length values ​​of each straight line segment can be determined first, then the difference between the theoretical diameter of the wafer and the sum of the length values ​​of each straight line segment can be determined, and then half of the difference can be used as the compensation value for the corresponding measurement point.

[0127] 3) Based on the compensation value corresponding to the measurement point, the length of the straight line segment on one side of the measurement point, and the maximum distance from the rotation center along the wafer radial direction among the multiple connection points on the same side of the measurement point, determine the correction value corresponding to the edge data of the measurement point.

[0128] As mentioned earlier, the multiple straight line segments used to fit the warping of the wafer surface are distributed on both sides of the plane where the rotation center is located. Therefore, the length value of the straight line segment on any one side can be used to determine the correction value corresponding to the edge data of the measurement point.

[0129] As a specific example, first determine the sum of the length values ​​of all straight line segments on the same side of the measurement point as the first total length value. Then, determine the sum of the compensation value corresponding to the measurement point and the first total length value as the second total length value. Finally, determine the difference between the second total length value and the maximum distance value between the second total length value and the rotation center among multiple connection points on the same side, and use the difference as the correction value corresponding to the edge data of the measurement point.

[0130] S132, Based on the correction value corresponding to the edge data of each measurement point, the edge data of the corresponding measurement point is corrected to obtain the corrected edge data of each measurement point.

[0131] In practice, the corrected edge data of each measurement point can be obtained by using a preset calculation method based on the correction value corresponding to the edge data of each measurement point and the edge data of each measurement point.

[0132] As a specific example, the correction value corresponding to the edge data of the measurement point can be summed with the edge data to form the corrected edge data of the corresponding measurement point.

[0133] In practical implementation, the device for acquiring edge data of each measurement point (e.g., the first data acquisition unit shown below) and the device for acquiring multiple height data of each measurement point relative to a preset reference (e.g., the second data acquisition unit shown below) may be arranged along different radial directions of the wafer, that is, the first data acquisition unit and the second data acquisition unit may not be on a straight line. Using the pre-alignment scheme in the embodiments of this specification, edge data of each measurement point and multiple height data of each measurement point relative to a preset reference can be acquired simultaneously. However, the edge data of each measurement point and the multiple height data of each measurement point relative to the preset reference may be stored in different storage units of the control module shown below. Therefore, before correcting the edge data of the measurement point according to the correction value determined by the height data, it is necessary to align the edge data of the measurement point with its corresponding correction value.

[0134] As a specific example, the edge data of the measurement points can be aligned with their corresponding correction values ​​based on the number of measurement points, a preset angle value (which could refer to the angle between the straight lines along different radial directions of the first and second data acquisition units on the wafer and the rotation center), and the rotation angle value of the wafer. This improves the correspondence between the edge data of the measurement points and their corresponding correction values, thereby enhancing the accuracy of the corrected edge data.

[0135] By adopting the above correction scheme, based on multiple height data of each measurement point and the theoretical diameter of the wafer, the correction value corresponding to the edge data of each measurement point can more accurately reflect the degree of influence of wafer surface warping on the theoretical diameter of the wafer. Furthermore, by correcting the edge data of the corresponding measurement point based on the correction value corresponding to the edge data of each measurement point, the accuracy of obtaining the corrected edge data of each measurement point can be improved.

[0136] By correcting the edge data of each measurement point based on multiple height data of each measurement point relative to a preset reference, the influence of wafer surface warping on the edge data of each measurement point can be eliminated. Then, based on the corrected edge data, the center coordinates of the wafer and the alignment angle of the wafer relative to the pre-aligned position can be determined.

[0137] Reference Figure 4 The flowchart shown in this specification illustrates a method for adjusting wafer position in some embodiments of this specification, such as... Figure 4 As shown, the following steps can be taken to perform the procedure:

[0138] S141 converts the corrected edge data of each measurement point into the corresponding coordinate values.

[0139] Specifically, the correction data of the measurement point can be regarded as the value in the polar coordinate system, while the pre-alignment position can be regarded as the value in the rectangular coordinate system. That is, the correction data and the pre-alignment position are parameter values ​​in different coordinate systems. The position of the wafer cannot be directly adjusted based on the correction data of the measurement point. Therefore, the correction data of the measurement point can be converted into coordinate values ​​in the rectangular coordinate system.

[0140] In some embodiments of this specification, the coordinate values ​​in a rectangular coordinate system corresponding to the measurement point correction data can be determined in the following manner.

[0141] As an example, if during a pre-alignment process, when the wafer rotates 360°, A (where A is an integer greater than or equal to 1) measurement points can be obtained evenly distributed on the circumference, and the edge data corresponding to these A measurement points are B1, B2, ..., B... i B A Then the angle corresponding to the first edge data can be β1 = 360° / A; the angle corresponding to the second edge data can be β2 = 360°*2 / A; and the angle corresponding to the i-th edge data can be β i =360°*i / A, where i is an integer greater than 0 and less than or equal to A.

[0142] Correspondingly, the coordinates of the first edge data after transformation are (B1cosβ1, B1sinβ1), the coordinates of the second edge data after transformation are (B2cosβ2, B2sinβ2), ..., the coordinates of the i-th edge data after transformation are (B1cosβ1, B1sinβ1 ...1, B1sinβ1), ..., the coordinates of the i-th edge data after transformation are (B i cosβ i B i sinβ i ).

[0143] S142, Determine the center coordinates of the wafer based on the coordinates of each measurement point.

[0144] Specifically, based on the coordinate values ​​of each measurement point, the fitted circle corresponding to the wafer can be obtained, and thus the center coordinate value of the wafer can be determined.

[0145] For example, a preset fitting algorithm is used to fit the coordinate values ​​of each measurement point to obtain the fitting circle corresponding to the wafer, and the center coordinate value of the fitting circle is determined as the center coordinate value of the wafer.

[0146] As a concrete example, using the least squares method, we can obtain the coordinates of the wafer's center and its radius:

[0147]

[0148] Where x0 represents the distance of the wafer's center along the x-axis in the rectangular coordinate system, and y0 represents the distance of the wafer's center along the y-axis in the rectangular coordinate system. i The distance along the x-axis in a Cartesian coordinate system represents the coordinate value of any edge data after transformation. i The distance along the y-axis in a Cartesian coordinate system represents the coordinate value of any edge data after transformation, and r represents the actual radius of the wafer. The current position of the wafer can be determined based on x0 and y0.

[0149] Because a preset fitting algorithm is used, a fitted circle that reflects the wafer's morphology can be obtained. The resulting wafer center coordinates can more accurately reflect the actual coordinates of the wafer's center, further improving alignment accuracy.

[0150] In specific implementation, such as Figure 5 As shown, a schematic diagram of the changes in edge data at each measurement point is presented, where the horizontal axis represents the rotation angle θ, and the vertical axis represents the edge data Φ, with the unit being μm.

[0151] like Figure 5 As shown, the edge data of the wafer measurement points generally shows a trend of first increasing and then decreasing. However, when the wafer is rotated to a certain angle (e.g., the rotation angle shown by the dashed line), the edge data of the measurement points decreases sharply and differs significantly from the edge data of other measurement points.

[0152] The inventors further discovered that... Figure 5 The reason for this situation is that the wafer surface has a marking structure (which can be a cut edge or notch on the wafer) to characterize the current position of the wafer. When a measurement point (called a feature point) located on the marking structure is detected, the corresponding edge data will decrease sharply. Therefore, before using a preset fitting algorithm to fit the coordinate values ​​of each measurement point to obtain the fitted circle corresponding to the wafer, the following steps are also included:

[0153] The coordinate values ​​of feature points among the measurement points are removed, that is, the coordinate values ​​of other measurement points are used to determine the fitted circle.

[0154] Since the coordinate values ​​of feature points vary significantly relative to the coordinate values ​​of other measurement points, removing the coordinate values ​​of feature points from the measurement points can yield a more accurate fitted circle, further improving alignment accuracy.

[0155] S143, determine the alignment angle of the wafer relative to the pre-alignment position based on the coordinate values ​​of each measurement point.

[0156] Specifically, the alignment angle can be determined based on the coordinate values ​​of the feature points in the measurement point.

[0157] In practice, different methods can be used to determine the alignment angle based on the location of the feature point.

[0158] As a specific example, the feature point may be located on the tangent edge of the wafer. The slope of the straight line corresponding to the tangent edge can be determined based on the coordinate value of the feature point, and the angle value corresponding to the slope can be used as the alignment angle of the wafer.

[0159] For example, such as Figure 6a As shown, the slope of the straight line corresponding to the tangent edge can be determined based on the coordinate values ​​of the feature points P1 and P3 that are in contact with the circumference of the wafer. For example, the slope of the straight line corresponding to the tangent edge can be determined based on the feature point P2 located at the center of the tangent edge and at least one of the feature points P1 and P3, and the angle value corresponding to the slope can be used as the alignment angle.

[0160] In practice, feature points located on the tangent edge can form multiple straight lines, and at least two of these lines have different slopes. In this case, the slope of any two feature points can be calculated, and then the average slope value of each slope value can be determined. The angle value corresponding to the average slope value can then be used as the alignment angle.

[0161] As another specific example, the feature point can be located in the notch of the wafer. Based on the coordinate value of the feature point located at the lowest point in the notch and the coordinate value of the center of the wafer, the slope of the straight line formed by the feature point located at the lowest point and the center of the wafer is determined, and the angle value corresponding to the slope is used as the alignment angle of the wafer.

[0162] For example, such as Figure 6b As shown, the alignment angle can be determined by the coordinates of the feature point P4 at the lowest point in the notch and the coordinates of the wafer center O, the slope of the straight line formed by the feature point P4 and the wafer center O, and the angle value corresponding to the slope.

[0163] S144, Based on the center coordinates of the wafer, the alignment angle, and the pre-alignment position, generate the position adjustment signal to adjust the position of the wafer.

[0164] Specifically, based on the center coordinates of the wafer and the pre-alignment position, the center offset value of the wafer is determined. The center offset value represents the distance the wafer needs to be displaced. Since the alignment angle represents the angle required for the wafer to rotate to the pre-alignment position, a position adjustment signal can be generated to control the wafer to move according to the alignment angle and the center offset value based on the alignment angle and the center offset value.

[0165] As a specific example, the alignment position in the embodiments of this specification can be the location of the rotation center. That is, by using the pre-alignment method in the embodiments of this specification, the alignment of the wafer center with the rotation center can be achieved.

[0166] To facilitate understanding, the pre-alignment method in the embodiments of this specification will be described in detail below through specific examples and in conjunction with specific application scenarios.

[0167] Reference Figure 7 The flowchart shown in this specification illustrates a pre-alignment method in a specific application scenario, as illustrated in the embodiments. Figure 7 As shown, the wafer can be pre-aligned by following these steps:

[0168] S21, acquire edge data of each measurement point on the wafer.

[0169] As a specific example, the edge data can be the distance from the circumference of the wafer to the center of rotation.

[0170] S22, obtain the height of the connection point of each straight line segment relative to the preset reference.

[0171] S23, for any straight line segment on any side, along the wafer radial direction, determine the length of the straight line segment based on the distance between the first connection point and the second connection point of the straight line segment, and the height difference between the second connection point and the first connection point relative to the preset reference.

[0172] For example, such as Figure 8 As shown, L1 represents the plane where the rotation center is located, and L2 represents the plane where the wafer circumference is located. The warp curve located on one side of L1 can be divided into 4 straight line segments.

[0173] During wafer movement, the first connection point e of the first straight line segment can be obtained. 11 With the second connection point e 12 The distance along the wafer radial direction is d, and the first connection point e of the first straight line segment is... 11 With the second connection point e 12 If the height difference relative to the preset reference is h1, then the length d1 of the first straight segment is:

[0174]

[0175] Correspondingly, the length d2 of the second straight segment is:

[0176]

[0177] Where d represents the first connection point e of the second straight line segment. 21 With the second connection point e 22 The distance along the wafer's radial direction, h2, represents the first connection point e of the second straight line segment. 21 With the second connection point e 22 The height difference relative to the preset reference.

[0178] The length d3 of the third straight segment is:

[0179]

[0180] Where d represents the first connection point e of the third straight line segment. 31 With the second connection point e 32 The distance along the wafer's radial direction, h3, represents the first connection point e of the three straight line segments. 31 With the second connection point e 32 The height difference relative to the preset reference.

[0181] Unlike the other three straight line segments, the fourth straight line segment is flush with the preset reference, and the length of the fourth straight line segment can be d4.

[0182] See also Figure 8 In some embodiments of this specification, the first connection point e of the first straight line segment11 It can coincide with the center of rotation, the second connection point e of the first straight line segment 11 It can connect to the first point e of the second straight line segment. 21 Connected.

[0183] S24, determine the sum of the lengths of all straight line segments distributed on both sides of the plane containing the preset rotation center.

[0184] Specifically, Figure 8 The diagram only shows the straight line segment corresponding to the warp curve on one side of L1. When calculating the compensation value of the measurement point, it is necessary to determine all the straight line segments corresponding to the warp curve of the wafer in the entire diameter direction.

[0185] Similarly, if it is determined that there are 4 straight line segments corresponding to the warped curve on the other side of L1 (it can be understood that there can also be 2 or 3 straight line segments corresponding to the warped curve on the other side of L1, and this specification does not impose any restrictions on this), then the lengths of these 4 straight line segments can be d1', d2', d3', and d4' respectively. The specific calculation process of d1', d2', d3', and d4' can be found in the aforementioned example, and will not be elaborated here.

[0186] Then the sum of the lengths of all line segments on both sides of L1, d s :

[0187] d s = d1+ d2+ d2+ d4+ d1'+ d2'+ d3'+ d4' (5)

[0188] S25, determine the difference between the theoretical diameter of the wafer and the sum of the lengths of each straight segment, and use half of the difference as the compensation value for the corresponding measurement point.

[0189] Specifically, since the theoretical diameter of the wafer remains constant, the compensation value of the measurement point can be determined based on the sum of the lengths of each straight line segment.

[0190] As a specific example, assuming the theoretical diameter of the wafer is D, the compensation value δ at the measurement point is:

[0191] δ=(D- d s ) / 2 (6)

[0192] S26, determine the sum of the lengths of all straight line segments on the same side of the plane where the measurement point is located, and use it as the first total length value.

[0193] S27, determine the sum of the compensation value corresponding to the measurement point and the first total length value, and use it as the second total length value.

[0194] S28, determine the difference between the second total length value and the maximum distance value from the rotation center among multiple connection points on the same side, and use it as the correction value corresponding to the edge data of the measurement point.

[0195] As a specific example, the correction value Δ corresponding to the edge data of the measurement point can be determined according to formula (7):

[0196] Δ=(d1+ d2+ d2+ d4+ δ)-(3d+ d4) (7)

[0197] S29, based on the number of measurement points, the preset included angle value, and the rotation angle value of the wafer, align the edge data of the measurement points with their corresponding correction values.

[0198] As a specific example, assuming the preset included angle is 18 degrees, the wafer rotates once, and the number of measurement points collected is 2000. Then, the correction value Δ needs to be offset to the corresponding edge data by the deflection value 18 / (360 / 2000) = 100, so that each correction value can be aligned with each edge data.

[0199] S30, the sum of the correction value corresponding to the edge data of the measurement point and the edge data is used as the correction edge data of the corresponding measurement point.

[0200] Specifically, by using steps S22 to S29, the correction value corresponding to any measurement point can be obtained, and then it can be added to the edge data of the obtained measurement point. The sum of the two is the correction edge data of the measurement point.

[0201] S31 converts the corrected data of each measurement point into the corresponding coordinate values.

[0202] For specific conversion methods, please refer to the examples mentioned above.

[0203] S32, Remove the coordinate values ​​of feature points from the measurement points.

[0204] S33, using a preset fitting algorithm, the coordinate values ​​of each measurement point are fitted to obtain the fitting circle corresponding to the wafer, and the center coordinate value of the fitting circle is determined as the center coordinate value of the wafer.

[0205] S34, determine the center offset value of the wafer based on the center coordinates of the wafer and the pre-alignment position.

[0206] In practice, different methods can be used to determine the alignment angle based on the location of the feature points.

[0207] As a specific example, the feature point may be located on the tangent edge of the wafer.

[0208] S35, based on the coordinate values ​​of the feature points, determine the slope of the straight line corresponding to the cut edge, and use the angle value corresponding to the slope as the alignment angle of the wafer.

[0209] As a specific example, the feature point may be located at a notch in the wafer.

[0210] S36. Based on the coordinates of the feature point at the lowest point in the notch and the coordinates of the center of the wafer, determine the slope of the straight line formed by the feature point at the lowest point and the center of the wafer, and use the angle value corresponding to the slope as the alignment angle of the wafer.

[0211] S37, Adjust the position of the wafer based on the alignment angle and the wafer center offset value.

[0212] It should be noted that, Figure 8 The example described uses four straight line segments on each side of the plane containing the rotation center. In practice, the number of straight line segments used to fit the warp curve can be determined based on the wafer size and the degree of warping on the wafer surface. This specification does not limit the number of straight line segments on each side of the plane containing the rotation center, as long as the correction values ​​corresponding to the edge data of the measurement points can be determined based on the straight line segments.

[0213] This specification also provides a pre-alignment system corresponding to the above-described pre-alignment method, which will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0214] It should be noted that the pre-alignment system described below can be considered as a functional module required to implement the pre-alignment method provided in this specification; the content of the pre-alignment system described below can be referred to in correspondence with the content of the pre-alignment method described above.

[0215] Reference Figure 9 The diagram shown is a structural schematic of a pre-alignment system in one embodiment of this specification. In some embodiments of this specification, the pre-alignment system may include:

[0216] The control module MC is adapted to generate motion control signals; and is adapted to correct the edge data of each measurement point of wafer W based on multiple height data of each measurement point of wafer W relative to a preset reference, determine the corrected edge data of each measurement point, and generate a position adjustment signal based on the corrected edge data of each measurement point and the pre-alignment position, wherein the position adjustment signal is used to control and adjust the position of wafer W; wherein the height data is used to characterize the degree of warpage of the surface of wafer W.

[0217] The carrier module MP is adapted to carry and drive the wafer W to move in response to the motion control signal;

[0218] The data acquisition module MD is suitable for acquiring edge data of each measurement point on wafer W, as well as acquiring multiple height data of each measurement point relative to a preset reference.

[0219] Specifically, the carrier module MP can respond to the motion control signal output by the control module MC, carry and drive the wafer W to move. During the movement of the wafer W, the data acquisition module MD can acquire the edge data of each measurement point on the surface of the wafer W in motion, as well as the multiple height data of each measurement point relative to the preset reference, and output the edge data of each measurement point and the multiple height data of each measurement point relative to the preset reference to the control module MC.

[0220] The control module MC can correct the edge data of each measurement point based on multiple height data points relative to a preset reference. Since the height data can be used to characterize the degree of warpage of the wafer surface, the influence of wafer surface warpage on the edge data of each measurement point can be eliminated, improving the accuracy of the obtained corrected edge data. Furthermore, the control module MC can improve the accuracy of the generated position adjustment signal based on the corrected edge data and pre-alignment position of each measurement point. Since the position adjustment signal can be used to control and adjust the position of the wafer, the alignment accuracy of the warped wafer can be improved.

[0221] The specific process of the control module determining the correction edge data of each measurement point based on multiple height data of each measurement point relative to the preset reference, and adjusting the wafer position based on the correction edge data and pre-alignment position of each measurement point, can be found in the aforementioned example and will not be described in detail here.

[0222] In some embodiments of this specification, in order to facilitate the acquisition of multiple height data of each measurement point relative to a preset reference, the plane of the carrier module can be used as the preset reference, that is, the height data can be the distance between the wafer surface and the plane where the carrier module is located.

[0223] In some other embodiments, the bottom surface of the wafer can be used as a preset reference.

[0224] In practice, height data is measured along the radial direction perpendicular to the wafer, while edge data is measured along the radial direction of the wafer. That is, height data and edge data are data located in different dimensions, so height data and edge data can be collected separately.

[0225] As a specific example, combined with Figure 9 and Figure 10 The data acquisition module (MD) may include:

[0226] The first data acquisition unit MD1 is located on opposite sides of the wafer W and is suitable for acquiring edge data of each measurement point on the wafer W.

[0227] The second data acquisition unit MD2 is located above the wafer W and is suitable for acquiring multiple height data of each measurement point of the wafer W relative to a preset reference.

[0228] Specifically, when wafer W is in motion, the first data acquisition unit MD1 acquires edge data of each measurement point of wafer W, while the second data acquisition unit MD2 acquires multiple height data of each measurement point of wafer W relative to a preset reference.

[0229] In some embodiments of this specification, such as Figure 10 As shown, the first data acquisition unit MD1 and the second data acquisition unit MD2 are located on the same side of the plane where the rotation center O1 of the carrier module MP is located. In some other embodiments, the first data acquisition unit MD1 and the second data acquisition unit MD2 are located on different sides of the plane where the rotation center O1 of the carrier module MP is located. This specification does not impose any restrictions on the placement of the first data acquisition unit MD1 and the second data acquisition unit MD2, as long as the edge data of the measurement point and the height of the measurement point relative to the carrier module can be acquired.

[0230] It should be noted that, Figure 10 Taking a wafer with diced edges as an example, the relative distribution positions of the first and second data acquisition units are illustrated. For other types of wafers with identification structures, the relative distribution positions of the first and second data acquisition units can be determined according to... Figure 10 The method shown can also be set in other ways. This specification does not impose any restrictions on this method, as long as the edge data of the same measurement point and multiple height data of the same measurement point relative to the preset reference can be obtained.

[0231] In a specific implementation, the first data acquisition unit can be a through-beam laser width sensor, which can include a laser emitter and a laser receiver. The laser emitter and the laser receiver can be located on opposite upper and lower sides of the wafer. The edge data can be determined by the time between the emission pulse and the reception pulse.

[0232] In a specific implementation, the second data acquisition unit can be a displacement sensor, which can acquire the height of the connection point of the straight line segment corresponding to the warp curve of the wafer surface relative to the plane of the carrier module.

[0233] As mentioned earlier, wafer surface warpage exists in the form of curves, and the parameters of these curves (e.g., length, slope, etc.) are difficult to determine. Therefore, in some embodiments of this specification, the wafer surface warpage can be segmented and fitted with straight line segments.

[0234] In this case, the height data obtained can be the height of the connection point of each straight line segment relative to the preset reference. Therefore, it is necessary to obtain the height of the connection point of each straight line segment relative to the preset reference.

[0235] As a specific example, the second data acquisition unit may include multiple sub-data acquisition units. Each sub-data acquisition unit may be arranged along the same radial direction of the wafer and distributed on both sides of the plane where the rotation center of the carrier module is located. For the sub-data acquisition units distributed on one side of the measurement point, the distance between the sub-data acquisition unit closest to the plane where the rotation center is located and the rotation center is a first distance, and the distance between each sub-data acquisition unit is a second distance, and the first distance and the second distance are the same.

[0236] As a specific example, continue to refer to Figure 10 The second data acquisition unit MD2 may include a first sub-data acquisition unit MD21, a second sub-data acquisition unit MD22, and a third sub-data acquisition unit MD23 located on one side of the plane where the rotation center O1 of the carrier module MP is located. These three sub-data acquisition units may be arranged along the same radial direction of the wafer W (e.g., along the radial direction shown by line l2), wherein the first sub-data acquisition unit MD21 is closest to the rotation center O1, and as shown... Figure 11 As shown, the distance between the first sub-data acquisition unit MD21 and the rotation center O1 is the first distance D1, the distance between the first sub-data acquisition unit MD21 and the second sub-data acquisition unit MD22 is the second distance D2, and the distance between the second sub-data acquisition unit MD22 and the third sub-data acquisition unit MD23 is the second distance D3, wherein D1, D2 and D3 are all the same.

[0237] Continue to refer to Figure 11 This allows the distance between the third sub-data acquisition unit MD23 and the rotation center O1 to be smaller than the theoretical diameter D of the wafer, so that the height data of all measurement points on the circumference of the wafer relative to the preset reference can be obtained.

[0238] It should be noted that, firstly, Figure 11This example illustrates the use of three sub-data acquisition units on one side of the plane containing the rotation center. In practice, the number of sub-data acquisition units for acquiring height data can be determined based on the wafer size and the degree of warpage on the wafer surface. This specification does not limit the number of sub-data acquisition units on either side of the plane containing the rotation center, as long as multiple height data points relative to a preset reference can be acquired using these sub-data acquisition units. Secondly, the distances between the nearest sub-data acquisition unit to the plane containing the rotation center and the rotation center, as well as the distances between the sub-data acquisition units, can all be different. Furthermore, the distance between the farthest sub-data acquisition unit to the plane containing the rotation center and the rotation center can be equal to the theoretical diameter of the wafer. Finally, Figure 11 The illustrated sub-data acquisition unit and the first data acquisition unit are simplified descriptions used to illustrate that the pre-alignment system has devices capable of acquiring edge data and height data, and therefore should not be construed as limiting the invention.

[0239] In some embodiments of this specification, the number of straight line segments used to simulate wafer surface warping can be determined based on the number of sub-data acquisition units. For example, in combination with Figure 8 and Figure 10 If the pre-alignment system includes 3 sub-data acquisition units, then 4 straight line segments corresponding to a measurement point can be determined.

[0240] It is understood that the relative quantitative relationship between the number of sub-data acquisition units and the number of line segments mentioned above is only for illustrative purposes, and the embodiments in this specification do not impose any restrictions on the relative quantitative relationship between the two.

[0241] In practice, if the first data acquisition unit and the second data acquisition unit are set along the same radial direction of the wafer, there may be a situation where the first data acquisition unit and the second data acquisition unit block each other, thus making it impossible to acquire edge data or height data. Therefore, the first data acquisition unit and the second data acquisition unit can be set along different radial directions of the wafer.

[0242] For example, continue to refer to Figure 10 The first data acquisition unit MD1 is set radially along line A, while the second data acquisition unit MD2 is set radially along line B, and there is an angle between the line connecting line A and the rotation center O1 and the line connecting line B and the rotation center O1.

[0243] In specific implementation, when adopting... Figure 10When using a pre-alignment system with the distribution positions shown, the pre-alignment system can simultaneously acquire edge data of each measurement point and multiple height data of each measurement point relative to a preset reference. However, since the first data acquisition unit and the second data acquisition unit are arranged along different radial directions of the wafer, the edge data of each measurement point and multiple height data of each measurement point relative to the preset reference may be stored in different storage units in the control module. Therefore, before correcting the edge data of the measurement point according to the correction value determined by the height data, it is necessary to align the edge data of the measurement point with its corresponding correction value.

[0244] As a specific example, if the angle between the first data acquisition unit and the second data acquisition unit along the straight lines of different radial directions of the wafer and the rotation center is α, and the rotation angle of the wafer is φ, and the number of measurement points acquired by the first data acquisition unit is N, then the deflection value that the correction value needs to be offset to the corresponding edge data is α / (φ / N) to compensate for the corresponding edge data.

[0245] It is understood that the above description provides multiple embodiment solutions, and the optional methods described in each embodiment solution can be combined and cross-referenced with each other without conflict, thereby extending to a variety of possible embodiment solutions, all of which can be considered as the embodiment solutions disclosed and made public in this specification.

[0246] In practical implementation, the aforementioned pre-alignment system can be applied to a wafer edge-tracking machine, which then performs wafer positioning and alignment operations. The structure and working principle of the pre-alignment system can be found in the previous example and will not be elaborated upon here.

[0247] In specific implementation, such as Figure 12 The diagram shown is a structural block diagram of a data processing device provided in an embodiment of this specification. Figure 12 In the process, the data processing device 120 may include a memory 121 and a processor 122, which can communicate with each other via a communication bus 123. The memory 121 stores computer instructions that can be executed on the processor 122. When the processor 122 executes the computer instructions, it can perform the pre-alignment method described in any of the above embodiments. For details, please refer to the above-mentioned related content, which will not be repeated here.

[0248] In specific implementations, the processor may include a central processing unit (CPU), a field-programmable gate array (FPGA), etc.

[0249] The memory may include random access memory (RAM), read-only memory (ROM), non-volatile memory (NVM), etc.

[0250] In practice, computer instructions may include any suitable type of code implemented using any appropriate high-level, low-level, object-oriented, visual, compiled, and / or interpreted programming language, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, encrypted code, etc.

[0251] In specific implementation, such as Figure 12 As shown, the data processing device 120 may further include a display interface 124 and a display 125 connected via the display interface 124. The display interface 124 can communicate with the memory 121 and the processor 122 via a communication bus 123. The display 125 can display the results obtained by the processor 122 executing the pre-alignment method provided in the embodiments of this specification. In specific implementations, such as... Figure 12 As shown, the data processing device 120 may further include a data output interface 126. The data output interface 126 can communicate with the memory 121 and the processor 122 via the communication bus 123 to output various data in the pre-alignment process.

[0252] The present invention also provides a computer-readable storage medium storing computer instructions thereon, which, when executed, can perform the pre-alignment method described in any of the above embodiments of the present invention. For details, please refer to the above-mentioned related content, which will not be repeated here.

[0253] The computer-readable storage medium may include any suitable type of memory cell, memory device, memory article, memory medium, storage device, storage article, storage medium and / or storage cell. Examples include memory, removable or non-removable media, erasable or non-erasable media, writable or rewritable media, digital or analog media, hard disk, floppy disk, optical disc read-only memory (CDROM), recordable optical disc (CD-R), rewritable optical disc (CD-RW), optical disc, magnetic media, magneto-optical media, removable memory cards or disks, various types of digital universal optical discs (DVDs), magnetic tape, cassette tape, etc.

[0254] Furthermore, computer instructions may include any suitable type of code implemented using any appropriate high-level, low-level, object-oriented, visual, compiled, and / or interpreted programming language, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, encrypted code, etc.

[0255] While the embodiments disclosed in this specification are as described above, the present invention is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A pre-alignment method characterized by, include: The edge data of each measurement point on the wafer and multiple height data of each measurement point relative to a preset reference are obtained. The height data is used to characterize the degree of warpage of the wafer surface. The height data is the height of the connection point of each straight line segment relative to the preset reference. The straight line segment is used to fit the warpage of the wafer surface. Based on multiple height data of each measurement point relative to a preset reference, the edge data of each measurement point is corrected to determine the corrected edge data of each measurement point. This includes: determining the correction value corresponding to the edge data of each measurement point based on the multiple height data of each measurement point and the theoretical diameter of the wafer; correcting the edge data of the corresponding measurement point based on the correction value corresponding to the edge data of each measurement point to obtain the corrected edge data of each measurement point; wherein, there are multiple straight line segments, which are distributed on both sides of the plane where the preset rotation center is located, and the connection points of the straight line segments on the same side are connected sequentially; determining the correction value corresponding to the edge data of each measurement point based on the multiple height data of each measurement point and the theoretical diameter of the wafer includes: determining the length value of any one of the multiple straight line segments based on the multiple height data of the measurement point; determining the compensation value of the measurement point based on the length value of each straight line segment of the measurement point and the theoretical diameter of the wafer; determining the correction value corresponding to the edge data of the measurement point based on the compensation value corresponding to the measurement point, the length value of the straight line segment on one side of the measurement point, and the maximum distance value from the rotation center along the radial direction of the wafer among the multiple connection points on the same side of the measurement point. Based on the corrected edge data and pre-alignment position of each measurement point, a position adjustment signal is generated, which is used to control and adjust the position of the wafer.

2. The pre-alignment method according to claim 1, characterized in that, The step of determining the length value of any one of multiple straight line segments based on multiple height data of measurement points includes: For any straight line segment on any side, along the radial direction of the wafer, the length of the straight line segment is determined based on the distance between the first connection point and the second connection point of the straight line segment, and the height difference between the second connection point and the first connection point relative to the preset reference. The first connection point of the straight line segment closest to the rotation center coincides with the rotation center.

3. The pre-alignment method according to claim 2, characterized in that, Along the radial direction of the wafer, the distance between the first connection point and the second connection point of each straight line segment is the same, and the maximum distance between the connection point and the rotation center is less than the theoretical diameter of the wafer.

4. The pre-alignment method according to claim 1, characterized in that, The step of determining the compensation value for the measurement point based on the length of each straight segment of the measurement point and the theoretical diameter of the wafer includes: Determine the sum of the lengths of all line segments; The difference between the theoretical diameter of the wafer and the sum of the lengths of each straight line segment is determined, and half of the difference is used as the compensation value for the corresponding measurement point.

5. The pre-alignment method according to claim 1, characterized in that, The step of determining the correction value corresponding to the edge data of the measurement point based on the compensation value corresponding to the measurement point, the length value of the straight line segment on one side of the measurement point, and the maximum distance value from the rotation center along the radial direction of the wafer among multiple connection points on the same side of the measurement point includes: Determine the sum of the lengths of all straight line segments on the same side of the measurement point, and use this sum as the first total length value; The sum of the compensation value corresponding to the measurement point and the first total length value is determined as the second total length value; The difference between the second total length value and the maximum distance value from the rotation center among multiple connection points on the same side is determined as the correction value corresponding to the edge data of the measurement point.

6. The pre-alignment method according to claim 1, characterized in that, The step of correcting the edge data of each measurement point based on the correction value corresponding to the edge data of each measurement point to obtain the corrected edge data of each measurement point includes: The sum of the correction value corresponding to the edge data of the measurement point and the edge data is used as the correction edge data of the corresponding measurement point.

7. The pre-alignment method according to claim 6, characterized in that, Before accumulating the correction value corresponding to the edge data of the measurement point with the edge data, the method further includes: Based on the number of measurement points, the preset included angle value, and the rotation angle value of the wafer, the edge data of the measurement points are aligned with their corresponding correction values.

8. The pre-alignment method according to claim 1, characterized in that, The step of generating a position adjustment signal based on the corrected edge data and pre-alignment position of each measurement point, wherein the position adjustment signal is used to control and adjust the position of the wafer, includes: Convert the corrected edge data of each measurement point into the corresponding coordinate values; Based on the coordinate values ​​of each measurement point, determine the center coordinate value of the wafer and the alignment angle of the wafer relative to the pre-alignment position; The position adjustment signal is generated based on the center coordinates of the wafer, the alignment angle, and the pre-alignment position to adjust the position of the wafer.

9. The pre-alignment method according to claim 8, characterized in that, Determining the center coordinates of the wafer based on the coordinates of each measurement point includes: A preset fitting algorithm is used to fit the coordinate values ​​of each measurement point to obtain the fitting circle corresponding to the wafer, and the center coordinate value of the fitting circle is determined as the center coordinate value of the wafer.

10. The pre-alignment method according to claim 9, characterized in that, Before the step of using a preset fitting algorithm to fit the coordinate values ​​of each measurement point to obtain the fitted circle corresponding to the wafer, the method further includes: Remove the coordinate values ​​of feature points from the measurement points.

11. The pre-alignment method according to claim 10, characterized in that, The feature points are located on the tangent edge of the wafer; Determining the alignment angle of the wafer relative to the pre-alignment position based on the coordinate values ​​of each measurement point includes: Based on the coordinate values ​​of the feature points, the slope of the straight line corresponding to the cut edge is determined, and the angle value corresponding to the slope is used as the alignment angle of the wafer.

12. The pre-alignment method according to claim 10, characterized in that, The feature point is located at the notch of the wafer; Determining the alignment angle of the wafer relative to the pre-alignment position based on the coordinate values ​​of each measurement point includes: Based on the coordinates of the feature point at the lowest point in the notch and the coordinates of the center of the wafer, the slope of the straight line formed by the feature point at the lowest point and the center of the wafer is determined, and the angle value corresponding to the slope is used as the alignment angle of the wafer.

13. The pre-alignment method according to claim 8, characterized in that, The step of generating the position adjustment signal based on the center coordinates of the wafer, the alignment angle, and the pre-alignment position includes: The center offset value of the wafer is determined based on the center coordinates of the wafer and the pre-alignment position. The position adjustment signal is generated based on the alignment angle and the center offset value of the wafer.

14. A pre-alignment system, characterized in that, include: The control module is suitable for generating motion control signals; And adapted to correct the edge data of each measurement point on the wafer based on multiple height data of each measurement point relative to a preset reference, determine the corrected edge data of each measurement point, and generate a position adjustment signal based on the corrected edge data of each measurement point and a pre-alignment position, wherein the position adjustment signal is used to control and adjust the position of the wafer; wherein, the height data is used to characterize the degree of warpage of the wafer surface, the height data is the height of the connection point of each straight line segment relative to the preset reference, and the straight line segment is used to fit the warpage of the wafer surface; the step of correcting the edge data of each measurement point based on multiple height data of each measurement point relative to the preset reference and determining the corrected edge data of each measurement point includes: determining the correction value corresponding to the edge data of each measurement point based on multiple height data of each measurement point and the theoretical diameter of the wafer; and adjusting the edge data of each measurement point based on the edge data of each measurement point. The corresponding correction value is used to correct the edge data of the corresponding measurement point to obtain the corrected edge data of each measurement point; wherein, there are multiple straight line segments, which are distributed on both sides of the plane where the preset rotation center is located, and the connection points of the straight line segments on the same side are connected sequentially; the step of determining the correction value corresponding to the edge data of each measurement point based on the multiple height data of each measurement point and the theoretical diameter of the wafer includes: determining the length value of any one of the multiple straight line segments based on the multiple height data of the measurement point; determining the compensation value of the measurement point based on the length value of each straight line segment of the measurement point and the theoretical diameter of the wafer; determining the correction value corresponding to the edge data of the measurement point based on the compensation value corresponding to the measurement point, the length value of the straight line segment on one side of the measurement point, and the maximum distance value from the rotation center along the radial direction of the wafer among the multiple connection points on the same side of the measurement point. The carrier module is adapted to carry and drive the wafer to move in response to the motion control signal; The data acquisition module is suitable for acquiring edge data of each measurement point on the wafer, as well as acquiring multiple height data of each measurement point relative to a preset reference.

15. The pre-alignment system according to claim 14, characterized in that, The data acquisition module includes: The first data acquisition unit is located on opposite sides of the wafer and is suitable for acquiring edge data of each measurement point on the wafer. The second data acquisition unit is located above the wafer and is suitable for acquiring multiple height data of each measurement point on the wafer relative to a preset reference.

16. The pre-alignment system according to claim 15, characterized in that, The second data acquisition unit includes multiple sub-data acquisition units, each of which is arranged radially along the wafer and distributed on both sides of the plane where the rotation center of the carrier module is located. For the sub-data acquisition units distributed on one side of the measurement point, the distance between the sub-data acquisition unit closest to the plane where the rotation center is located and the rotation center is a first distance, and the distance between each sub-data acquisition unit is a second distance, and the first distance and the second distance are the same.

17. A wafer edge-tracing machine, characterized in that, include: The pre-alignment system as described in any one of claims 14 to 16.

18. A data processing device, characterized in that, The device includes a memory and a processor, wherein the memory is adapted to store one or more computer instructions, and the processor, when executing the computer instructions, performs the pre-alignment method according to any one of claims 1 to 13.

19. A computer-readable storage medium, characterized in that, The device stores computer instructions that, when executed, perform the pre-alignment method according to any one of claims 1 to 13.

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